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Lim, Hui Fern Michele. "Low Temperature Co-fired Ceramics Technology for Power Magnetics Integration." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/30156.
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This dissertation focuses on the development of low-temperature co-fired ceramics (LTCC) technology for power converter magnetics integration. Because magnetic samples must be fabricated with thick conductors for power applications, the conventional LTCC process is modified by cutting trenches in the LTCC tapes where conductive paste is filled to produce thick conductors to adapt to this requirement. Characterization of the ceramic magnetic material is performed, and an empirical model based on the Steinmetz equation is developed to help in the estimation of losses at frequencies between 1 MHz to 4 MHz, operating temperature between 25 °C and 70 °C, DC pre-magnetization from 0 A/m to 1780 A/m, and AC magnetic flux densities between 5 mT to 50 mT. Temperature and DC pre-magnetization dependence on Steinmetz exponents are included in the model to describe the loss behavior.
In the development of the LTCC chip inductor, various geometries are evaluated. Rectangular-shaped conductor geometry is selected due to its potential to obtain a much smaller footprint, as well as the likelihood of having lower losses than almond-shaped conductors with the same cross-sectional area, which are typically a result of screen printing. The selected geometry has varying inductance with varying current, which helps improve converter efficiency at light load. The efficiency at a light-load current of 0.5 A can be improved by 30 %. Parametric variation of inductor geometry is performed to observe its effect on inductance with DC current as well as on converter efficiency. An empirical model is developed to describe the change in inductance with DC current from 0 A to 16 A for LTCC planar inductors fabricated using low-permeability tape with conductor widths between 1 mm to 4 mm, conductor thickness 180 μm to 550 μm, and core thickness 170 μm to 520 μm. An inductor design flow diagram is formulated to help in the design of these inductors.
Configuring the inductor as the substrate carrying the semiconductor and the other electronic components is a next step to freeing the surface area of the bulky component and improving the power density. A conductive shield is introduced between the circuitry and the magnetic substrate to avoid adversely affecting circuit operation by having a magnetic substrate in close proximity to the circuitry. The shield helps reduce parasitic inductances when placed in close proximity to the circuitry. A shield thickness in the range of 50 μm to 100 μm is found to be a good compromise between power loss and parasitic inductance reduction. The shield is effective when its conductivity is above 107 S/m. When a shield is introduced between the inductor substrate and the circuitry, the sample exhibits a lower voltage overshoot (47 % lower) and an overall higher efficiency (7 % higher at 16 A), than an inductor without a shield. A shielded active circuitry placed on top of an inductive substrate performs similarly to a shielded active circuitry placed side-by-side with the inductor. Using a floating shield for the active circuitry yields a slightly better performance than using a grounded shield.Ph. D.
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Shafique, Muhammad Farhan. "Laser Prototyping of Low Temperature Co-fired Ceramics for System-In-Package Applications." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521480.
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Bhutani, Akanksha [Verfasser]. "Low Temperature Co-fired Ceramics for System-in-Package Applications at 122 GHz / Akanksha Bhutani." Karlsruhe : KIT Scientific Publishing, 2019. http://d-nb.info/1196294542/34.
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Zhang, Wenli. "HIGH PERFORMANCE PIEZOELECTRIC MATERIALS AND DEVICES FOR MULTILAYER LOW TEMPERATURE CO-FIRED CERAMIC BASED MICROFLUIDIC SYSTEMS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/200.
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The incorporation of active piezoelectric elements and fluidic components into micro-electromechanical systems (MEMS) is of great interest for the development of sensors, actuators, and integrated systems used in microfluidics. Low temperature cofired ceramics (LTCC), widely used as electronic packaging materials, offer the possibility of manufacturing highly integrated microfluidic systems with complex 3-D features and various co-firable functional materials in a multilayer module. It would be desirable to integrate high performance lead zirconate titanate (PZT) based ceramics into LTCC-based MEMS using modern thick film and 3-D packaging technologies. The challenges for fabricating functional LTCC/PZT devices are: 1) formulating piezoelectric compositions which have similar sintering conditions to LTCC materials; 2) reducing elemental inter-diffusion between the LTCC package and PZT materials in co-firing process; and 3) developing active piezoelectric layers with desirable electric properties.
The goal of present work was to develop low temperature fired PZT-based materials and compatible processing methods which enable integration of piezoelectric elements with LTCC materials and production of high performance integrated multilayer devices for microfluidics. First, the low temperature sintering behavior of piezoelectric ceramics in the solid solution of Pb(Zr0.53,Ti0.47)O3-Sr(K0.25, Nb0.75)O3 (PZT-SKN) with sintering aids has been investigated. 1 wt% LiBiO2 + 1 wt% CuO fluxed PZT-SKN ceramics sintered at 900oC for 1 h exhibited desirable piezoelectric and dielectric properties with a reduction of sintering temperature by 350oC. Next, the fluxed PZT-SKN tapes were successfully laminated and co-fired with LTCC materials to build the hybrid multilayer structures. HL2000/PZT-SKN multilayer ceramics co-fired at 900oC for 0.5 h exhibited the optimal properties with high field d33 piezoelectric coefficient of 356 pm/V. A potential application of the developed LTCC/PZT-SKN multilayer ceramics as a microbalance was demonstrated. The final research focus was the fabrication of an HL2000/PZT-SKN multilayer piezoelectric micropump and the characterization of pumping performance. The measured maximum flow rate and backpressure were 450 μl/min and 1.4 kPa respectively. Use of different microchannel geometries has been studied to improve the pumping performance. It is believed that the high performance multilayer piezoelectric devices implemented in this work will enable the development of highly integrated LTCC-based microfluidic systems for many future applications.
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Luo, Jin. "The Development and Biocompatibility of Low Temperature Co-Fired Ceramic (LTCC) for Microfluidic and Biosensor Applications." UKnowledge, 2014. http://uknowledge.uky.edu/cme_etds/30.
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Low temperature co-fired ceramic (LTCC) electronic packaging materials are applied for their electrical and mechanical properties, high reliability, chemical stability and ease of fabrication. Three dimensional features can also be prepared allowing integration of microfluidic channels and cavities inside LTCC modules. Mechanical, optical, electrical, microfluidic functions have been realized in single LTCC modules. For these reasons LTCC is attractive for biomedical microfluidics and Lab-on-a-Chip systems. However, commercial LTCC systems, optimized for microelectrics applications, have unknown cytocompatibility, and are not compatible with common surface functionalization chemistries.
The first goal of this work is to develop biocompatible LTCC materials for biomedical applications. In the current work, two different biocompatible LTCC substrate materials are conceived, formulated and evaluated. Both materials are based from well-known and widely utilized biocompatible materials. The biocompatibilities of the developed LTCC materials for in-vitro applications are studied by cytotoxicity assays, including culturing endothelial cells (EC) both in LTCC leachate and directly on the LTCC substrates. The results demonstrate the developed LTCC materials are biocompatible for in-vitro biological applications involving EC.
The second goal of this work is to develop functional capabilities in LTCC microfluidic systems suitable for in-vitro and biomedical applications. One proposed application is the evaluation of oxygen tension and oxidative stress in perfusion cell culture and bioreactors. A Clark-type oxygen sensor is successfully integrated with LTCC technique in this work. In the current work, a solid state proton conductive electrolyte is used to integrate an oxygen sensor into the LTCC. The measurement of oxygen concentration in Clark-type oxygen sensor is based on the electrochemical reaction between working electrode and counter electrode. Cyclic voltammetry and chronoamperometry are measured to determine the electrochemical properties of oxygen reduction in the LTCC based oxygen sensor. The reduction current showed a linear relationship with oxygen concentration. In addition, LTCC sensor exhibits rapid response and sensitivity in the physiological range 1─9 mg/L. The fabricated devices have the capabilities to regulate oxygen supply and determination of local dissolved oxygen concentration in the proposed applications including perfusion cell culture and biological assays.
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Ahyoune, Saiyd. "Heterogeneous Integration of RF and Microwave Systems Using Multi-layer Low-Temperature Co-fired Ceramics Technology." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/459117.
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The aim of this work is the development of a modelling methodology for the fast analysis of non-radiative multilayer RF passive components without compromising solution accuracy. Instead of following a compact model approach, oftenly used in integrated technologies, the method is based on a specialized quasi-static partial element equivalent circuit (PEEC) numerical solver. Besides speed and accuracy, the solver can be embedded in circuit simulators; thus, models are already available in the schematic entry. Using this framework, model scalability is enhanced in terms of geometry, substrate cross-section, material properties, topology and boundary conditions.
The dissertation starts showing the actual performance of the obtained solver and the motivations beneath its development. Then, the description about solver development is splitted in three parts, but all of them are interrelated. First, the PEEC formulation is adapted according to relevant electromagnetic behaviour of the component. It is worth stressing that a different perspective related to the principle of virtual work is used in this formulation. The second part deals with the evaluation of partial elements, the core of the solver. It is carried out using analytical space-domain close-form solutions of the Green’s function (GF) of the substrate. Partial elements are then assembled into a mesh. Therefore, the importance of the mesh up on solution accuracy is discussed in the last part and a basic layout aware mesh generator is proposed.
Practical application of the methodology includes the implementation of a library of RF passives for multilayer substrate. For validation, the chosen substrate is a low temperature co-fired ceramics (LTCC) technology. Different set of devices have been fabricated, characterized and compared against model prediction. In addition, the obtained results are also verified using state-of-the-art electromagnetic solvers.El objetivo de este trabajo es el desarrollo de una metodología de modelado para el análisis rápido, pero sin comprometer la precisión de la solución, de componentes pasivos no radiativos de RF en substratos multicapa. El método se basa en el algoritmo numérico cuasi-estático de los elementos parciales de circuito equivalente (PEEC). Éste puede ser incorporado en simuladores de circuitos; por tanto, los modelos ya están disponibles en la entrada de esquemático de forma transparente para el diseñador de circuitos. Utilizando este marco, la escalabilidad del modelo se mejora en términos de la geometría, la definición del corte tecnológico, las propiedades del material, la topología del componente y las condiciones de contorno electro-magnéticas. Esta disertación comienza mostrando las motivaciones que han llevado a su desarrollo y la capacidad real del método de resolución obtenido. A partir de aquí, se realiza la descripción de todo el desarrollo del marco numérico que se divide en tres partes que están interrelacionadas. En primer lugar, la formulación PEEC se adapta según el comportamiento electromagnético real del componente. Vale la pena subrayar que en esta formulación se utiliza una perspectiva diferente a la habitual y que está relacionada con el principio de los trabajos virtuales de d’Alembert. La segunda parte trata de cómo se evalúan los elementos parciales y constituye el núcleo principal del algoritmo. Se lleva a cabo utilizando soluciones analíticas de la función de Green (GF) del sustrato en el dominio espacial. Los elementos parciales, que forman la malla numérica del modelo, se ensamblan en la matriz del sistema siguiendo un procedimiento de análisis nodal modificado (MNA). En la última parte, se discute la importancia de la malla sobre la precisión de la solución y se propone un generador de malla basado en la física del componente y no sólo en la descripción de la geometría. Como aplicación práctica de la metodología, se realiza la generación de una biblioteca de componentes pasivos RF para sustratos multicapa.
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Mercke, William L. "Diagnosis of Systemic Inflammation Using Transendothelial Electrical Resistance and Low-Temperature Co-fired Ceramic Materials." UKnowledge, 2013. http://uknowledge.uky.edu/cme_etds/21.
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Systemic inflammation involves a complex array of cytokines that can result in organ dysfunction. Mortality remains high despite the vast amount of research conducted to find an effective biomarker. The cause of systemic inflammation can be broad and non-specific; therefore, this research investigates using transendothelial electrical resistance (TEER) measurements to better define systemic inflammatory response syndrome (SIRS)/sepsis within a patient. Results show a difference in TEER measurements between healthy individuals and SIRS-rated patients. This research also displays correlations between TEER measurements and biomarkers currently studied with systemic inflammation (tumor necrosis factor-α, C- reactive protein, procalcitonin). Furthermore, this research also presents the groundwork for developing a microfluidic cell-based biosensor using low temperature co-fired ceramic materials. An LTCC TEER-based microfluidic device has the potential to aid in a more effective treatment strategy for patients and potentially save lives.
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Bhutani, Akanksha [Verfasser], and T. [Akademischer Betreuer] Zwick. "Low Temperature Co-fired Ceramics for System-in-Package Applications at 122 GHz / Akanksha Bhutani ; Betreuer: T. Zwick." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/119312719X/34.
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Gilham, David Joel. "Packaging of a High Power Density Point of Load Converter." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/19325.
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Due to the power requirements for today\'s microprocessors, point of load converter packaging is becoming an important issue. Traditional thermal management techniques involved in removing heat from a printed circuit board are being tested as today\'s technologies require small footprint and volume from all electrical systems. While heat sinks are traditionally used to spread heat, ceramic substrates are gaining in popularity for their superior thermal qualities which can dissipate heat without the use of a heat sink. 3D integration techniques are needed to realize a solution that incorporates the active and components together. The objective of this research is to explore the packaging of a high current, high power density, high frequency DC/DC converter using ceramic substrates to create a low profile converter to meet the needs of current technologies.One issue with current converters is the large volume of the passive components. Increasing the switching frequency to the megahertz range is one way to reduce to volume of these components. The other way is to fundamentally change the way these inductors are designed. This work will explore the use of low temperature co-fired ceramic (LTCC) tapes in the magnetic design to allow a low profile planar inductor to be used as a substrate. LTCC tapes have excellent properties in the 1-10 MHz range that allow for a high permeability, low loss solution. These tapes are co-fired with a silver paste as the conductor. This paper looks at ways to reduce dc resistance in the inductor design through packaging methods which in turn allow for higher current operation and better heavy load efficiency. Fundamental limits for LTCC technologies are pushed past their limits during this work. This work also explores fabrication of LTCC inductors using two theoretical ideas: vertical flux and lateral flux. Issues are presented and methods are conceived for both types of designs. The lateral flux inductor gives much better inductance density which results in a much thinner design.
It is found that the active devices must be shielded from the magnetic substrate interference so active layer designs are discussed. Alumina and Aluminum Nitride substrates are used to form a complete 3D integration scheme that gives excellent thermal management even in natural convection. This work discusses the use of a stacked power technique which embeds the devices in the substrate to give double sided cooling capabilities. This fabrication goes away from traditional photoresist and solder-masking techniques and simplifies the entire process so that it can be transferred to industry. Time consuming sputtering and electroplating processes are removed and replaced by a direct bonded copper substrate which can have up to 8 mil thick copper layers allowing for even greater thermal capability in the substrate. The result is small footprint and volume with a power density 3X greater than any commercial product with comparable output currents. A two phase coupled inductor version using stacked power is also presented to achieve even higher power density.
As better device technologies come to the marketplace, higher power density designs can be achieved. This paper will introduce a 3D integration design that includes the use of Gallium Nitride devices. Gallium Nitride is rapidly becoming the popular device for high frequency designs due to its high electron mobility properties compared to silicon. This allows for lower switching losses and thus better thermal characteristics at high frequency. The knowledge learned from the stacked power processes gives insight into creating a small footprint, high current ceramic substrate design. A 3D integrated design is presented using GaN devices along with a lateral flux inductor. Shielded and Non-Shielded power loop designs are compared to show the effect on overall converter efficiency. Thermal designs and comparisons to PCB are made using thermal imaging. The result is a footprint reduction of 40% from previous designs and power densities reaching close to 900W/in3.
Master of Science
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Li, Qiang. "Low-Profile Magnetic Integration for High-Frequency Point-of-Load Converter." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/28637.
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Today, every microprocessor is powered with a Voltage Regulator (VR), which is also known as a high current Point-of-Load converter (POL). These circuits are mostly constructed using discrete components, and populated on the motherboard. With this solution, the passive components such as inductors and capacitors are bulky. They occupy a considerable footprint on the motherboard. The problem is exacerbated with the current trend of reducing the size of all forms of portable computing equipment from laptop to netbook, increasing functionalities of PDA and smart phones. In order to solve this problem, a high power density POL needs to be developed. An integration solution was recently proposed to incorporate passive components, especially magnetic components, with active components in order to realize the needed power density for the POL. Todayâ s discrete VR only has around 100W/in3 power density. The 3D integration concept is widely used for low current integrated POL. With this solution, a very low profile planar inductor is built as a substrate for the active components of the POL. By doing so, the POL footprint can be dramatically saved, and the available space is also fully utilized. This 3D integrated POL can achieve 300-1000W/in3 power density, however, with considerably less current. This might address the needs of small hand-held equipment such as PDA and Smart phone type of applications. It does not, however, meet the needs for such applications as netbook, laptop, desk-top and server applications where tens and hundreds of amperes are needed. So, although the high density integrated POL has been demonstrated at low current level, magnetic integration is still one of the toughest barriers for integration, especially for high current POL.
In order to alleviate the intense thirst from the computing and telecom industry for high power density POL, the 3D integration concept needs be extended from low current applications to high current applications. The key technology for 3D integration is the low profile planar inductor design. Before this research, there was no general methodology to analyze and design a low profile planar inductor due to its non-uniform flux distribution, which is totally different as a conventional bulky inductor. A Low Temperature Co-fired Ceramic (LTCC) inductor is one of the most promising candidates for 3D integration for high current applications. For the LTCC inductor, besides the non-uniform flux, it also has non-linear permeability, which makes this problem even more complicated. This research focuses on penetrating modeling and design barriers for planar magnetic to develop high current 3D integrated POL with a power density dramatically higher than todayâ s industry products in the same current level.
In the beginning, a general analysis method is proposed to classify different low profile inductor structures into two types according to their flux path pattern. One is a vertical flux type; another one is a lateral flux type. The vertical flux type means that the magnetic flux path plane is perpendicular with the substrate. The lateral flux type means that the magnetic flux path plane is parallel with the substrate. This analysis method allows us to compare different inductor structures in a more general way to reveal the essential difference between them. After a very thorough study, it shows that a lateral flux structure is superior to a vertical flux structure for low profile high current inductor design from an inductance density point of view, which contradicts conventional thinking. This conclusion is not only valid for the LTCC planar inductor, which has very non-linear permeability, but is also valid for the planar inductor with other core material, which has constant permeability.
Next, some inductance and loss models for a planar lateral flux inductor with a non-uniform flux are also developed. With the help of these models, different LTCC lateral flux inductor structures (single-turn structure and multi-turn structures) are compared systematically. In this comparison, the inductance density, winding loss and core loss are all considered. The proposed modeling methodology is a valuable extension of previous uniform flux inductor modeling, and can be used to solve other modeling problems, such as non-uniform flux transformer modeling.
After that, a design method is proposed for the LTCC lateral flux inductor with non-uniform flux distribution. In this design method, inductor volume, core thickness, winding loss, core loss are all considered, which has not been achieved in previous conventional inductor design methods. With the help of this design method, the LTCC lateral flux inductor can be optimized to achieve small volume, small loss and low profile at the same time. Several LTCC inductor substrates are also designed and fabricated for the 3D integrated POL. Comparing the vertical flux inductor substrate with the lateral flux inductor substrate, we can see a savings of 30% on the footprint, and a much simpler fabrication process. A 1.5MHz, 5V to 1.2V, 15A 3D integrated POL converter with LTCC lateral flux inductor substrate is demonstrated with 300W/in3 power density, which has a factor of 3 improvements when compared to todayâ s industry products.
Furthermore, the LTCC lateral flux coupled inductor is proposed to further increase power density of the 3D integrated POL converter. Due to the DC flux cancelling effect, the size of LTCC planar coupled inductor can be dramatically reduced to only 50% of the LTCC planar non-coupled inductor. Compared to previous vertical flux coupled inductor prototypes, a lateral flux coupled inductor prototype is demonstrated to have a 50% core thickness reduction. A 1.5MHz, 5V to 1.2V, 40A 3D integrated POL converter with LTCC lateral flux coupled inductor substrate is demonstrated with 700W/in3 power density, which has a factor of 7 improvements when compared to today's industry POL products in the same current level.
In conclusion, this research not only overcame some major academia problems about analysis and design for planar magnetic components, but also made significant contributions to the industry by successfully scaling the integrated POL from today's 1W-5W case to a 40W case. This level of integration would significantly save the cost, and valuable motherboard real estate for other critical functions, which may enable the next technological innovation for the whole computing and telecom industry.Ph. D.
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Chen, M. Y. (Mei-Yu). "Ultra-low sintering temperature glass ceramic compositions based on bismuth-zinc borosilicate glass." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526215600.
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Abstract In the first part of the thesis, novel glass-ceramic compositions based on Al2O3 and BaTiO3 and bismuth-zinc borosilicate (BBSZ) glass, sintered at ultra-low temperatures, were researched. With adequate glass concentration, dense microstructures and useful dielectric properties were achieved. The composite of BaTiO3 with 70 wt % BBSZ sintered at 450 °C exhibited the highest relative permittivity, εr, of 132 and 207 at 100 kHz and 100 MHz, respectively. Thus, the dielectric properties of the composites were dominated by the characteristics of glass, BaTiO3, and Bi24Si2O40 phase, especially the contribution of Bi24Si2O40 for the samples with 70-90 wt % glass. Actually, the existence of the secondary phase Bi24Si2O40 may not hinder but enhance the dielectric properties. The Al2O3-BBSZ composition samples showed a similar situation, not only for densification but also for their microstructures and phases (Al2O3, BBSZ, Bi24Si2O40), explaining the achieved dielectric properties. The second part of the thesis mainly discusses the composite of BaTiO3 with 50 wt % BBSZ with different thermal treatments. After sintering at 720 °C, dense microstructures and the existence of Bi4BaTi4O15, BaTiO3, Bi24Si2O40 phases were observed. The results also showed that the size of glass powder particles did not influence the dielectric properties (εr = 263-267, tan δ = 0.013 at 100 kHz) of sintered samples, but the addition of LiF degraded the dielectric properties due to the features and amount of Bi4BaTi4O15. These results demonstrate the feasibility of the BBSZ based composites for higher sintering temperature technologies as well. At the end, a novel binder system, which enables low sintering temperatures close to 300 °C, was developed. A dielectric multilayer module containing BaTiO3-BBSZ and Al2O3-BBSZ composites with silver electrodes was co-fired at 450 °C without observable cracks and diffusions. These results indicate that these glass-ceramic composites provide a new horizon to fabricate environmentally friendly ULTCC materials, as well as multilayers for multimaterial 3D electronics packages and high frequency devicesTiivistelmä Väitöstyön ensimmäisessä osassa tutkittiin ja kehitettiin uudentyyppisiä, ultramatalissa sintrauslämpötiloissa (ULTCC) valmistettuja lasi-keraami komposiitteja käyttäen vismuttisinkkiborosilikaatti -pohjaista lasia (BBSZ). Täyteaineina olivat alumiinioksidi (Al2O3) ja bariumtitanaatti (BaTiO3). Materiaaleille saatiin riittävän suuren lasipitoisuuden avulla tiheät mikrorakenteet ja sovelluskelpoiset dielektriset ominaisuudet. BaTiO3:n komposiitti, joka sisälsi 70 p-% BBSZ lasia, saavutti 450 °C lämpötilassa sintrattuna korkeimman suhteellisen permittiivisyyden: εr=132 (@100 kHz) ja εr=207 (@100 MHz). Komposiittien dielektrisiä ominaisuuksia määrittivät tällöin lasi-, BaTiO3- ja Bi24Si2O40- faasien ominaisuudet ja erityisesti Bi24Si2O40 -faasi näytteissä, joissa on 70-90 p-% lasia. Sekundäärinen faasi Bi24Si2O40 ei välttämättä heikentänyt, vaan jopa paransi dielektrisiä ominaisuuksia. Vastaavilla Al2O3-BBSZ –komposiiteilla saavutettiin samanlaisia tuloksia tihentymisen, mikrorakenteiden ja faasien (Al2O3, BBSZ, Bi24Si2O40) suhteen. Lisäksi tässä tapauksessa saavutetut dielektriset ominaisuudet voidaan selittää näiden kolmen faasin yhdistelmän olemassaololla. Väitöstyön toinen osa käsitteli pääasiassa eritavoin lämpökäsiteltyjä BaTiO3:n komposiitteja, joissa on 50 p-% BBSZ-lasia. Näillä saavutettiin tiheä mikrorakenne sintrattaessa 720 °C lämpötilassa ja havaitiin Bi4BaTi4O15-, Bi24Si2O40-faasien muodostuminen BaTiO3 lähtöfaasin rinnalle. Tulokset osoittivat myös, että lasijauheen partikkelikoko ei vaikuttanut sintrattujen näytteiden dielektrisiin ominaisuuksiin (εr = 263-267, tan δ = 0.013 (@100 kHz)). LiF -lisäys sen sijaan heikensi dielektrisiä ominaisuuksia ja vähensi Bi4BaTi4O15 faasin muodostumista. Tämä aiheutui Bi4BaTi4O15-faasin ominaisuuksista ja oli riippuvainen kyseisen faasin määrästä. Nämä tulokset osoittivat BBSZ -pohjaisten komposiittien käytettävyyden myös korkeampien sintrauslämpötilojen teknologioihin. Viimeisenä kehitettiin uudentyyppinen sideainesysteemi, joka mahdollistaa ultramatalien keraamien yhteissintraamisen jopa noin 300 °C lämpötilassa. Hyödyntäen kehitettyä sideainesysteemiä monikerrosrakenne, jossa käytettiin dielektrisiä BaTiO3-BBSZ- ja Al2O3-BBSZ-komposiitteja ja hopeaelektrodeja, yhteissintrattiin 450 °C lämpötilassa. Valmistetuissa rakenteissa ei havaittu murtumia eikä diffuusioita. Tulokset osoittavat, että kehitetyt lasi-keraami komposiitit mahdollistavat ympäristöystävällisten ULTCC -materiaalien valmistuksen. Lisäksi osoitettiin kehitettyjen materiaalien soveltuvuus monikerroksisten rakenteiden käyttöön monimateriaali-3D-elektroniikan pakkauksissa ja suurtaajuuskomponteissa
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Suarez, Willian Toito. "Desenvolvimento de procedimentos em fluxo envolvendo reatores em fase sólida e microssistema analítico construído com LTCC (Low Temperature Co-fired Ceramics) para a determinação de analitos de interesse farmacêutico." Universidade Federal de São Carlos, 2009. https://repositorio.ufscar.br/handle/ufscar/6111.
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Previous issue date: 2009-03-20Universidade Federal de Sao Carlos
The employment of flow injection systems to determination of N-acetylcysteine, captopril, dipyrone and fluoxetine hydrochloride in pharmaceutical formulations was investigated. The N-acetylcysteine was determinated employing a solid-phase reactor containing Zn3(PO4)2 immobilized in a polyester resin coupled to a flow injection system. The procedure was based on the chelation of Zn(II) ions with N-acetylcysteine in the solid-phase reactor, with consequent releasing of the complex Zn(II)-N-acetylcysteine of the reactor, this complex reacted with alizarin red S (VA) in borate buffer pH 9.0 generating the complex Zn(VA-BO3)3 which absorbance was measured spectrophotometrically at 540 nm. The second developed procedure was the determination of captopril (CAP) in pharmaceutical formulations employing a solid-phase reactor containing silver chrolanilate (Ag2C6Cl2O4) immobilized in a polyester resin. In this system occured the precipitation reaction of captopril with the Ag(I), producing in the reactor an insoluble salt between the CAP and the Ag(I) due to the lower solubility of the formed salt related to Ag2C6Cl2O4. After the formation of the insoluble salt in the reactor occured the releasing of chloranilate anion, C6Cl2O4 2-, that reacted with the Fe(III) producing the complex FeC6Cl2O4 + which was monitored spectrophotometrically at 528 nm. In another procedure, the N-acetylcysteine and captopril were determined separately in a flow injection system through the on-line of the Prussian blue formation. In this procedure, the N-acetylcysteine or the captopril were oxidized by Fe(III), producing Fe(II) that reacted with hexacyanoferrate(III) in a point of flow system, generating the Prussian blue (Fe4[Fe(CN)6]3), that was monitored spectrophotometrically at 700 nm. It was also proposed a flow injection system with merging zones and intermittent flow with turbidimetric detection to determination of fluoxetine hydrochloride in pharmaceuticals. This system was based on the formation of an insoluble salt (AgCl(s)) between the AgNO3 and the chloride of the hydrochloride of the fluoxetine molecule that was turbidimetrically detected at 420 nm. Finally, two procedures were developed employing a flow injection system to determination of dipyrone in pharmaceuticals using Fe(III) as chromogenic reagent. In the first procedure, it was employed an analytical microsystem constructed with LTCC and in the second one, it was used a flow injection system with merging zones without the use of microsystem. In these systems, occured the formation on-line of an blue chromophore between Fe(III) and the dipyrone that was monitored spectrophotometrically at 622 nm.
O emprego de sistemas de análise por injeção em fluxo para a determinação de N-acetilcisteína, captopril, dipirona e cloridrato de fluoxetina em formulações farmacêuticas foi investigado. A N-acetilcisteína foi determinada empregando um reator em fase sólida contendo fosfato de zinco imobilizado em resina poliéster acoplado ao sistema FIA. O procedimento baseou-se na complexação dos íons Zn(II) pela N-acetilcisteína no reator em fase sólida, com consequente remoção do complexo Zn(II)-N-acetilcisteína do reator, esse complexo reagiu com o regente vermelho de alizarina S (VA), em tampão borato pH 9,0, formando o complexo Zn(VA-BO3)3 cuja absorbância foi monitorada espectrofotometricamente em 540 nm. O segundo procedimento desenvolvido foi a determinação de captopril empregando um reator em fase sólida contendo cloranilato de prata (Ag2C6Cl2O4) imobilizado em resina poliéster. Esse sistema baseou-se na reação de precipitação do captopril com Ag(I), gerando no reator um sal insolúvel entre o captopril e Ag(I) devido à menor solubilidade do sal formado em relação ao Ag2C6Cl2O4. Após a formação do sal insolúvel no reator ocorreu o deslocamento do ânion cloranilato, C6Cl2O4 2-, que reagiu com o Fe(III) em um ponto de confluência do sistema em fluxo produzindo o complexo FeC6Cl2O4 + que foi monitorado espectrofotometricamente em 528 nm. Em um outro procedimento, a N-acetilcisteína e o captopril foram determinados separadamente em um sistema de análise por injeção em fluxo através da formação em linha do azul da Prússia. Nesse procedimento, a N-acetilcisteína ou o captopril foram oxidados pelo Fe(III), produzindo Fe(II) que reagiu com hexacianoferrato(III) em um ponto de confluência do sistema FIA, gerando o azul da Prússia (Fe4[Fe(CN)6]3), que foi monitorado espectrofotometricamente em 700 nm. Foi proposto também um sistema de análise por injeção em fluxo com zonas coalescentes e fluxo intermitente com detecção turbidimétrica para a determinação de cloridrato de fluoxetina em produtos farmacêuticos. O sistema baseou-se na reação entre o cloreto do cloridrato de fluoxetina e o nitrato de prata (AgNO3), formando o (AgCl(s)), que foi monitorado turbidimetricamente em 420 nm. Por último, foram desenvolvidos dois procedimentos empregando sistema de análise por injeção em fluxo para a determinação de dipirona em formulações farmacêuticas utilizando Fe(III) como reagente cromogênico. No primeiro procedimento foi empregado um microssistema analítico construído com LTCC e no segundo foi utilizado um sistema FIA com zonas coalescentes sem o acoplamento do microssistema. Nesses sistemas, sucedeu a formação em linha de um cromóforo azul, a partir da reação entre o Fe(III) e a dipirona, que foi monitorado espectrofotometricamente em 622 nm.
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Tlili, Malika. "Modules intégrés en technologie LTCC pour des applications en bande D (110 - 170 GHz)." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0165.
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Cette thèse a pour objectif de réaliser des modules d''émission-réception (front-end TRX) faible coût, en band D (110-170 GHz), utilisant des puces intégrées MMIC reportées sur un substrat LTCC. Les applications visées à ces fréquences sont diverses : l'imagerie (sécurité) par le déploiement de scanners haute résolution, les radars automobiles d'aide à la conduite, la radiométrie ou encore le "back-haul" du réseau de téléphonie 5G. Aux fréquences très élevées, les boîtiers sont généralement réalisés à partir de structures métalliques, ce qui les rend coûteux, volumineux et relativement longs à fabriquer. Des solutions de mise en boîtier basées sur la technologie LTCC ont été proposées et développées au cours de la thèse avec l'objectif de maintenir les performances intrinsèques des puces avant report. Pour intégrer les puces MMIC sur le support LTCC, différents aspects ont été étudiés et validés expérimentalement, avec les difficultés en mesure inhérentes à ces fréquences de fonctionnement très élevées. Il s'agit en particulier des techniques d'interconnexion pour relier les plots d'accès RF de la puce aux plots sur substrat et du contrôle technique pour maîtriser l'échauffement de certaines puces, comme l'amplificateur de puissance, qui peut provoquer un dysfonctionnement voire une défaillance du module. La mise en place des réseaux d'alimentation continue des puces actives est également un point crucial dans la conception du boîtier puisqu'ils ne doivent pas interférer avec les accès RFThis thesis has as objective to realize low cost front-end TRX modules, in D-band (110-170 GHz), using MMIC chips integrated on an LTCC substrate. The applications at these frequencies are various: imaging (security) by deploying high-resolution scanners, automotive assistance radars, radiometry or the backhaul of the 5G telephony network. At very high frequencies, the packaging is generally made of metal structures, which makes it expensive, bulky and relatively long to manufacture. Packaging solutions based on LTCC technology have been proposed and developped during the thesis with the objective of maintaining the intrinsic performance of chips before integration. To integrate the MMIC chips on th LTCC support, various aspects have been studied and validated experimentally, with the difficulties in measurement inherent to these very high operating frequencies. These are in particular interconnection techniques for connecting the RF access pads of the chip to the pads on the subtrate and the thermal solution to limit the heating of certain chips, such as the power amplifier, which can cause a malfunction of even failure of the module. The establishement of th DC blasing networks of active chips is also a crucial point in the design of the packaging since they must not interferer with the RF accesses
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Kosorín, Michal. "Výpočtové modelování porušení keramických částicových kompozitních materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418188.
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Subcritical crack growth in composite materials plays quite an important role in determination of the service life and leads to the defects growth below the fracture toughness. The thesis presents search of the several scientific works dealing with the determination of the crack growth direction in composite materials. The aim of this diploma thesis was to create 2D and 3D finite element models to analyse crack growth in Low Temperature Co-fired Ceramics (LTCC). These models were compared based on the time calculation of the crack propagation under the subcritical growth conditions.
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Svoboda, Josef. "Numerická simulace růstu trhliny v keramických kompozitních materiálech ve 3D." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318715.
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The strength of materials such as glass and ceramics can be influenced by the environment (stress corrosion). Under applied stress defects (cracks) can grow sub-critically below fracture toughness K_Ic. The aim of this work was to develop a three-dimensional finite-element model to analyze the subcritical crack growth behavior of ceramic-based particulate composites. The maximum tangential stress criterion (MTS) was used to predict the direction of the crack propagation in the framework of linear elastic fracture mechanics. The modeled material was a Low Temperature Co-fired Ceramics (LTCC), containing alumina particles embedded in a glass matrix. The main aim of this work was to develop a 3D model describing the crack growth. Conclusions from this work can contribute to a better understanding of subcritical crack propagation in particle composites.
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Sobocinski, M. (Maciej). "Embedding of bulk piezoelectric structures in low temperature co-fired ceramic." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526207049.
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Abstract It has been over a century since the Curie brothers discovered the piezoelectric effect. Since then our knowledge about this phenomena has been constantly growing, accompanied by a vast increase in its applications. Modern piezoelectric devices, especially those meant for use in personal equipment, can often have complicated shapes and electric circuits; therefore, a suitable and cost effective packaging method is needed. The recent introduction of self-constrained Low Temperature Co-fired Ceramic (LTCC) characterized by virtually no planar shrinkage has pushed the limits of this technology a step further. The practical lack of dimension change between “green” state and sintered ceramic has not only improved the design of multilayer smart packages but also allowed the embedding of other bulk materials within the LTCC and their co-firing in one sintering process. This thesis introduces a novel method of seamlessly embedding piezoelectric bulk structures in LTCC by co-firing or bonding with adhesive. Special attention is paid to the multistage lamination and post-firing poling of the piezoelectric ceramics. Examples of several structures from the main areas of piezoelectric applications are presented as proof of successful implementation of the new technique in the existing production environment. The performance of the structures is investigated and compared to structures manufactured using other methods. Integration of bulk piezoelectric structures through co-firing is a new technique with a wide area of applications, suitable for mass production using existing process flowTiivistelmä Curien veljekset havaitsivat pietsosähköisen ilmiön jo yli sata vuotta sitten. Ilmiöön liittyvä tutkimustieto ja erityisesti siihen perustuvien sovellusten määrä on nykyisin valtava. Uusissa pietsosähköisissä komponenteissa ja varsinkin niissä, jotka on tarkoitettu henkilökohtaisissa laitteissa käytettäviksi, muodot samoinkuin elektroniikapiirit voivat olla monimutkaisia. Siksi tarvitaan tarkoituksenmukaista ja hinnaltaan edullista laitteen pakkausmenetelmää. Hiljattain kehitetyt itseohjautuvat matalan lämpötilan yhteissintattavat keraamit (LTCC), joiden planaarinen kutistuma on lähes olematon, ovat lisänneet LTCC-teknologian sovellusmahdollisuuksia. Muotoon valmistetun sintraamattoman ja lopullisen sintratun keraamin dimensioiden yhtäsuuruus ei ole ainoastaan parantanut älykkäiden monikerrospakkausten suunnittelua, vaan mahdollistanut myös erilaisten materiaalien ja komponenttien upottamisen LTCC-rakenteisiin ja niiden yhteissintrauksen. Väitöstyössä esitetään uusi menetelmä pietsosähköisten bulkrakenteiden upottamiseksi saumattomasti LTCC-rakenteisiin yhteissintrauksella tai liimaliitoksella. Erityistä huomiota on kiinnitetty monivaiheiseen laminointiin ja sintrauksen jälkeiseen pietsosähköisten keraamien polarisointiin. Työssä on esitetty esimerkkejä useista rakenteista pietsosähköisten sovellusten pääalueilta osoituksena uuden tekniikan onnistuneesta käyttöönottamisesta nykyisessä valmistusympäristössä. Tutkittujen uusien rakenteiden ja muilla menetelmillä valmistettujen rakenteiden ominaisuuksia on verrattu keskenään. Pietsosähköisten bulkrakenteiden integroiminen yhteissintrauksella on uusi tekniikka, joka mahdollistaa lukuisia sovelluksia ja soveltuu massatuotantoon olemassa olevilla prosseintilaitteistoilla
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Smarra, Devin A. "Low Temperature Co-Fired Ceramic (LTCC) Substrate for High Temperature Microelectronics." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1493386231571894.
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Hu, T. (Tao). "BST-based low temperature co-fired ceramic (LTCC) modules for microwave tunable components." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514272927.
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Abstract
The recent trend in low temperature co-fired ceramic (LTCC) technology is to integrate more elements into multilayer modules. This thesis describes work specifically aimed at developing ferroelectric barium strontium titanate (BST) for integration into such modules. In particular, an objective was the development of a novel, electric field controlled, tunable component to be used at microwave frequencies (2–26 GHz).
For the application envisaged, relative permittivity is required to be low (100–1000) and adjustable by a suitable applied electric field, the dissipation factor at room temperature must be low (~0.001) at 2–26 GHz, and most importantly, the sintering temperature must be suited to the LTCC technology (~900 °C)
Initial work was focused on sol-gel derived Ba0.7Sr0.3TiO3 powders with boron oxide addition, which were sintered at 900 °C, the dissipation factor was 0.006. The dissipation factor was not low enough for the desired microwave application, and attention turned to powders prepared by the mixed-oxide route. The Ba0.7Sr0.3TiO3 powders, fluxed with the optimum amounts of boron oxide and lithium carbonate, could be sintered at 890 °C to the same density as is achieved with un-fluxed Ba0.7Sr0.3TiO3 sintered at 1360 °C. The dissipation factor for this fluxed powder was acceptably low, although permittivity was too high for the particular objective. Subsequently, research was on BST modified by magnesia, 0.4Ba0.55Sr0.45TiO3-0.6MgO (BSTM). With the optimum fluxing additives, the sintering temperature necessary to achieve a dense BSTM-based ceramic was reduced to 950 °C. The developed microstructure was good, and the relative permittivity and dissipation factor values (221, 0.0012 at 1 kHz) at room temperature indicated good microwave properties.
Studies were also undertaken with organic-based tape-casting slurries, laminating procedures and burn-out and sintering schedules. Several kinds of tapes were fabricated and characterized.
A test structure for the measurement of dielectric properties at 26 GHz of the optimized BSTM-based ceramic was constructed. The specimen was 50 μm thick layer of BST on an alumina substrate. The relative permittivity and tunability were 130 and >15 % at 4 V μm-1 at room temperature. A tunable phase-shifter was fabricated from the same BSTM-based tape using a novel gravure printing technique, and measurements at 26 GHz showed phase shift from 10 to 35° when the electric field was increased from 1 V μm-1 to 2.5 V μm-1.
Some exploratory experiments are described to assess the compatibility of the developed BST-based LTCC with commercial LTCC and some electroceramics.
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Ho, Christopher M. (Christopher Mark). "Manufacturing operation modeling for product redesign : resistance analysis of low-temperature co-fired ceramic circuits." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36521.
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Rathnayake-Arachchige, Dilshani. "Metallisation and structuring of low temperature Co-fired ceramic for micro and millimetre wave applications." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19343.
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The recent developments in Low Temperature Co-fired Ceramic (LTCC) as a substrate material enable it to be used in the micro and millimetre wave range providing low dissipation factors at high frequencies, good dielectric properties and a high degree of integration for further miniaturised devices. The most common metallisation method used in LTCC technology is screen printing with high cost noble metals such as silver and gold that are compatible with the high sintering temperatures (850°C). However, these techniques require high capital cost and maintenance cost. As the commercial world requires convenient and low cost process technologies for mass production, alternative metallisation methods should be considered. As a result, electroless copper plating of fired LTCC was mainly investigated in this research. The main goals of this project were to carry out electroless plating of fired LTCC with sufficient adhesion and to extend the process to metallise closed LTCC channel structures to manufacture Substrate Integrated Waveguide (SIW) components. The objectives were focused on electroless copper deposition on fired LTCC with improved adhesion. Electroless deposits on the Sn/Pd activated LTCC surface showed poor adhesion without any surface pre-treatments. Hence, chemical etching of fired LTCC was carried out using concentrated NaOH solution. NaOH pre-treatment of LTCC led to the formation of flake like structures on the LTCC surface. A number of surface and chemical analysis techniques and weight measurements were used to investigate the mechanism of the modification of the LTCC surface. The results showed that the flake like structures were dispersed in the LTCC material and a material model for the LTCC structure was proposed. SEM EDX elemental mapping showed that the flake like structure consisted of aluminium, calcium, boron and oxygen. Further experiments showed that both the concentration of NaOH and the immersion time affect the surface morphology and the roughness of fired LTCC. The measured Ra values were 0.6 μm for untreated LTCC and 1.1 μm for the LTCC sample treated with 4M NaOH for 270 minutes. Adhesion tests including peel test and scratch test were carried out to examine the adhesion strength of the deposited copper and both tests indicated that the NaOH pre-treatment led to an improvement, with the best results achieved for samples treated with 4M NaOH. A second aspect of the research focused on the selective metallisation of fired LTCC. Excimer laser machining was used to pattern a resist film laminated on the LTCC surface. This process also roughened the substrate and created channels that were characterised with respect to the laser operating parameters. After patterning the resist layer, samples were activated using Sn/Pd catalyst solution followed by the electroless copper deposition. Electroless copper was selectively deposited only on the patterned LTCC surface. Laser parameters clearly affected the copper plating rate. Even with a similar number of shots per area, the tracks machined with higher repetition rate showed relatively more machining depth as well as good plating conditions with low resistance values. The process was further implemented to realize a complete working circuit on fired LTCC. Passive components including a capacitor and an inductor were also fabricated on LTCC using the mask projection technique of the excimer laser system. This was successful for many designs, but when the separation between conductor lines dropped below 18 μm, electroless copper started to deposit on the areas between them. Finally, a method to deposit copper films on the internal walls of closed channel structures was developed. The method was first demonstrated by flowing electroless copper solutions through silane treated glass capillaries. A thin layer (approx. 60 nm) of electroless copper was deposited only on the internal walls of the glass capillaries. The flow rate of the electroless copper solution had to be maintained at a low level as the copper deposits tended to wash away with higher flow rates. The structures were tested for transmission losses and showed low (<10dB) transmission losses in the terahertz region of the electromagnetic spectrum. The process was further applied to deposit electroless copper on the internal walls of the LTCC closed channel structures to manufacture a LTCC Substrate Integrated Waveguide (SIW).
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Yucel, Ayse Tugce. "Modeling And Control Of High Temperature Oven For Low Temperature Co-fired Ceramic (ltcc) Device Manufacturing." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614918/index.pdf.
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In the electronics the quality, reliability, operational speed, device density and cost of circuits are fundamentally determined by carriers. If it is necessary to use better material than plastic carrier, it has to be made of ceramics or glass-ceramics. This study dealt with the ceramic based carrier production system. The types of the raw ceramics fired at low temperature (below 1000°C) are called Low Temperature Co-Fired Ceramics (LTCC). In this study, a comprehensive thermal model is described for the high temperature oven which belongs to a Low Temperature Co-fired Ceramic (LTCC) substance production line. The model includes detailed energy balances with conduction, convection and radiation heat transfer mechanisms, view factor derivations for the radiative terms, thermocouple balances, heating filaments and cooling mechanisms for the system. Research was conducted mainly on process development and production conditions along with the system modeling of oven. Temperature control was made in high temperature co-firing oven. Radiation View Factors for substrate and thermocouples are determined. View factors between substrate and top-bottom-sides of the oven are calculated, and then inserted into the energy balances. The same arrangement was made for 3 thermocouples at the bottom of the oven. Combination of both expressions gave the final model. Modeling studies were held with energy balance simulations on MATLAB. Data analysis and DOE study were held with JMP Software.
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Fernandes, Joana Gonçalves. "Development and optimization of a Low Temperature Co-fired Ceramic suspension for Mask-Image-Projection-based Stereolithography." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/667478.
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This dissertation has the main goal of developing ceramic materials for Mask-Image- Projection-based Stereolithography (MIP-SLA) technology, focused on electronic applications. To accomplish this aim, a low temperature co-fired ceramic (LTCC) material was selected, mainly used for radio frequency applications. Moreover, the proof of concept of AM technology hybridization and multi-materials printing is also demonstrated, opening the door to new researchers in the field of 3D-2D printing electronic devices, from both the material and technology perspectives.
To successfully achieve the main goal, the different steps of the whole process were successfully achieved, i.e, formulation of a LTCC photocurable suspension, its printability by MIP-SLA technology, and the post-thermal treatment of debinding and sintering.
The photocurable LTCC suspension consists of ceramic particles dispersed in a suitable photocurable resin, which must polymerize in the visible light range, trapping the ceramic particles. The challenge of the development and optimization of a LTCC photocurable suspension for MIP-SLA with the appropriate rheological and photocurable behavior is accomplished in this work.
The printed piece contains the polymeric part, which must be removed (debinding) and then sintered for the densification of the final ceramic piece. This is the most difficult and time- consuming step of the whole process. The so-called debinding is one of the most challenging steps of the SLA-based technology of ceramic materials. In this sense, a detailed study of the debinding process is carried out for a deeper understanding of the degradation of the resin during the thermal debinding. For this to happen, the optimization of the temperature rate and used atmosphere during the thermal treatment is also presented in this work. In fact, the analysis and understanding of thermal treatment parameters and their repercussion on the final results is the key to successfully achieving the main goal, which is to obtain final ceramic pieces without defects.
The limits of the MIP-SLA printing process are presented, analyzing the resolution, fidelity of pattern transfer, and accuracy of the printing process using the optimized LTCC suspension. The involved phenomena during the photopolymerization such as light scattering, non- uniformities of the light projection along the building platform and shrinkage during the polymerization, are analyzed and optimized for a fruitful printing process.
The greatest achievement of this work is the possibility of printing complex geometry with high resolution with a LTCC material, which has never been demonstrated before in the field of additive manufacturing. This is the beginning of new breakthroughs in multimaterial printing for electronic applications.El objetivo principal de la tesis doctoral es el desarrollo y optimización de una suspensión cerámica fotocurable para la fabricación aditiva mediante la tecnología Mask-Image- Projection-Based Stereolithography (MIP-SLA), y la obtención de piezas cerámicas finales. Durante el proceso de impresión, el fotopolímero reacciona con la luz proyectada atrapando las partículas cerámicas en su matriz, lo cual posibilita la impresión de piezas cerámicas en verde (matriz polimérica y partículas cerámicas). Después del proceso de impresión es necesario eliminar la parte orgánica y realizar la sinterización de la pieza para la obtención de la pieza cerámica final. El material cerámico seleccionado para la formulación de la suspensión fotocurables ha sido un cerámico de baja temperatura de co-sinterización (Low Temperature Co-fired Ceramics, LTCC), para aplicaciones electrónicas. Para el desarrollo de la suspensión fotocurable de LTCC se ha teniendo en cuenta su comportamiento reológico y sus propiedades de fotopolimerización adecuadas a la tecnología de impresión. Una vez optimizada la suspensión cerámica, se han analizado el proceso de impresión y se ha optimizado el ciclo térmico, tanto de la etapa de quemado del polímero (debinding) como del proceso de sinterización para la densificación de la pieza cerámica final. Se ha logrado una formulación adecuada a la tecnología, la cual ha permitido la impresión de piezas en verde y posterior debinding y sinterizado de las piezas con geometrías complejas. Se demuestra también la posibilidad de impresión de piezas cerámicas con circuitos impresos de plata, lo cual abre camino para el desarrollo de la impresión híbrida de multimateriales.
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Bhutani, Akanksha [Verfasser], and T. [Akademischer Betreuer] Zwick. "Low Temperature Co-fired Ceramic for System-in-Package Applications at 122 GHz / Akanksha Bhutani ; Betreuer: T. Zwick." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1192373545/34.
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Keezhanatham, Seshadri Jayashree. "Uniform Field Distribution Using Distributed Magnetic Structure." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24820.
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Energy distribution in a conventional magnetic component is generally not at a designer's disposal. In a conventional toroidal inductor, the energy density is inversely proportional to the square of the radius. Thus, a designer would be unable to prescribe uniform field distribution to fully utilize the inductor volume for storing magnetic energy.
To address this problem a new inductor design, called a "constant-flux" inductor, is introduced in this thesis. This new inductor has the core and windings configured to distribute the magnetic flux and energy relatively uniformly throughout the core volume to achieve power density higher than that of a conventional toroidal inductor. The core of this new inductor design is made of concentric cells of magnetic material, and the windings are wound in the gaps between the cells. This structure is designed to avoid crowding of the flux, thus ensuring lower core energy losses. In addition, the windings are patterned for shorter length and larger area of cross-section to facilitate lower winding energy losses.
Based on this approach, a set of new, constant flux inductor/transformer designs has been developed. This design set is based on specific input parameters are presented in this thesis. These parameters include the required inductance, peak and rms current, frequency of operation, permissible dc resistance, material properties of the core such as relative permeability, maximum permissible magnetic flux density for the allowed core loss, and Steinmetz parameters to compute the core loss. For each constant flux inductor/transformer design, the winding loss and core loss of the magnetic components are computed. In addition, the quality factor is used as the deciding criterion for selection of an optimized inductor/transformer design.
The first design presented in this thesis shows that for the same maximum magnetic field intensity, height, total stored energy, and material, the footprint area of the new five-cell constant-flux inductor is 1.65 times less than that of an equivalent conventional toroidal inductor. The winding loss for the new inductor is at least 10% smaller, and core loss is at least 1% smaller than that in conventional inductors. For higher energy densities and taller inductors, an optimal field ratio of the dimensions of each cell (α = Rimin/Rimax) and a larger number of cells is desired. However, there is a practical difficulty in realizing this structure with a larger number of cells and higher field ratio α. To address this problem, an inductor design is presented that has a footprint area of a three-cell constant-flux inductor (α = 0.6) that is 1.48 times smaller in comparison to an equivalent conventional toroidal inductor. For the same maximum magnetic flux density, height, material, and winding loss, the energy stored in this new three-cell constant-flux inductor (α = 0.6) is four times larger than that of an equivalent conventional toroidal inductor.
Finally, new designs for application-specific toroidal inductors are presented in this thesis. First, a constant-flux inductor is designed for high-current, high-power applications. An equivalent constant-flux inductor to a commercially available inductor (E70340-010) was designed. The height of this equivalent inductor is 20% less than the commercial product with the same inductance and dc resistance. Second, a constant-flux inductor design of inductance 1.2 µH was fabricated using Micrometal-8 for the core and flat wire of 0.97 mm x 0.25 mm for the conductor. The core material of this inductor has relative permeability < 28 and maximum allowed flux density of 3600 Gauss. The dc resistance of this new, constant flux inductor was measured to be 14.4 mΩ.Master of Science
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Jurásek, Matěj. "Studená chemická laminace keramiky s nízkou teplotou výpalu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-221030.
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This paper deals with production of the structures fabricated using low temperature co-fired ceramics. Focus is on the lamination of raw ceramic tapes. There are presented classical thermo-compressive methods and a new method using chemical solutions for tape bonding. Describes new lamination technology and their advantages are the absence of elevated temperatures and high pressures. This method reduces using of higher temperatures and high pressure during lamination. On the other hand, chemical process of tape bonding is not flawless. There are many problems including solvent deposition, extreme sensitivity to dust and other processing parameters. It also describes the fabrication of structures by chemical way. Specifically, analyzes the method Cold Chemical Lamination and provides examples of possible deposition solvents which are needed for etching the surface of the LTCC tape during the lamination.
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Symerský, Tomáš. "Senzor pro měření průtoku." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219280.
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This diploma thesis is divided into two parts - theoretical and practical. In its first, theoretical part, deals with the theory of fluid and gas flow, heat transfer and diversification of sensors for flow measurement working on the electrical principle. It also deals with thermodynamic principle, which can be used for measuring very small flow and low-temperature ceramics that is used to implement microcanals for sensing very low flows. The practical part of the thesis deals with the very simulation of the entire structure in the program “COMSOL Multiphysics” - both in 2D and 3D views. Then there is shown the implementation and measurement of the flow sensor in a low-temperature ceramics, working on a thermodynamic principle.
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曹淳凱. "Low temperature Co-fired ceramics of (MgCa)TiO3 microwave dielectiv materials." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/16921629125197175981.
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YANG, YOU-TING, and 楊侑庭. "Fabrication of LiNi0.5Ti0.5O2 low temperature co-fired ceramics with sintering aids." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/enft28.
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碩士國立高雄應用科技大學
電子工程系
105
This thesis investigated effects of sintering aids on the sintering behavior and microwave properties of LiN0.5Ti0.5O2(LNT) ceramics by the conventional solid-reaction route. LiN0.5Ti0.5O2 ceramic sintered at 1275 oC has good microwave properties. However, the sintering temperature is too high to be compatible with the low-temperature co-fire ceramics (LTCC) process. First, the CuO was added into LNT ceramics to act as the sintering aid. However, after the LNT ceramics with CuO were sintered at 925 oC, the relative density was only 71.5 % and many pores were observed in the LNT ceramic, which indicated that CuO did not form the liquid phase sintering to help the densification process. Hence, the CuO is not suitable to be a sintering aid for LNT ceramics. Then, ZnO was also added into LNT ceramics to be a sintering aid. However, ZnO also can not form the liquid phase sintering and hence the relative density of the LNT ceramic with ZnO sintered at 925 oC was only 67.64 %. Therefore, ZnO is still not suitable to be a sintering aid for the LNT ceramic. Finally, this study adopted V2O5 as the sintering aid. The V2O5 formed the liquid phase sintering with LNT ceramics. The LNT ceramic without a sintering aid sintered at 925 oC has the relative density of 68.45%. The relative density of the LNT ceramics increased with increasing the amount of V2O5. The LNT ceramic with 4 wt% V2O5 had the highest relative density of 97.31%. Then, the relative density decreased with larger V2O5 amount. The value also varied as the trend of relative density. Therefore, the value is influenced by amount of impurity and pores within the ceramics. The V2O5aid formed the liquid phase sintering in the LNT ceramics, which caused the densification process. Fewer pores within the LNT ceramics with V2O5 have higher values. The LNT ceramic with 4 wt% V2O5 sintered at 925 oC has an excellent microwave properties of =17.89, =20742 GHz, and = -29.93 ppm/℃. The LNT ceramic with 4 wt% V2O5 was alsoco-fired with 20 wt% Ag powders. No chemical reaction between the LNT ceramic and Ag powders was found, which indicates thatthe LNT ceramic with 4 wt% V2O5 is suitable for LTCC process.
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Chen-YoKo and 柯承佑. "Fabrication of a low temperature co-fired ceramics electromagnetic valveless micropump." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/31637095204795676279.
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Jhou, Pei-jia, and 周培家. "Thermal stress analysis of low temperature co-fired ceramics manufacturing processes." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/83089970971939912537.
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碩士國立中山大學
機械與機電工程學系研究所
94
In this study, stress problems occurring in low tempera -ture cofired ceramic processes are analyzed by finite element package ANSYS. Sintering stresses of sintering processes and residue stresses in cooling processes are investigated. The thermal shrinkage coefficient are used to deal with the density variation due to the shrinkage mismatch between the green tape and silver paste in the sintering processes. Deleting the elements is used to treat the situation when the element stress exceeds its fracture stress. The residue stresses due to the mismatch of the thermal expansion coefficients in cooling processes are also discussed.
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Che-ChuanKuo and 郭銓哲. "Fabrication of micro-droplet generators in low temperature co-fired ceramics." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/53700669731075282020.
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碩士國立成功大學
機械工程學系
103
When a liquid jet experiences axisymmetric disturbance, the disturbance grows in space, moves downstream, and eventually breaks up the jet into droplets. The phenomenon is called capillary instability, also known as Rayleigh breakup. Based on this instability, the present study develops droplet generators made of low temperature co-fired ceramics (LTCC). Both the monodisperse and multi-size droplet generators are successfully fabricated. The LTCC generator is driven by a piezoelectric disc attached directly on a LTCC diaphragm to provide the necessary disturbance. A backpressure is provided to the chamber of the generator such that a liquid jet can be formed steadily through a nozzle. Nozzles with different diameters are manufactured successfully by CO2 laser drilling. It is shown that the proportion of glass in the LTCC green tape and the parameters of laser drilling are key factors in fabricating the nozzle. Results show that the droplet sizes depend on excitation frequency, nozzle diameter and jet velocity. In the range of working frequency, the sizes of the droplets agree well with theoretical predictions.
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陳幼欣. "Study on Non-shrinkage Low Temperature Co-fired Al2O3 Microwave Dielectric Ceramics." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/47456433617626658863.
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Chen, Hua Pin, and 陳華娉. "Study of Thick-Film Resistors Embedded in Low Temperature Co-fired Ceramics." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/60014911576357783040.
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碩士義守大學
材料科學與工程學系
91
This study investigated the electrical properties of buried resistor in the borosilicate glass-ceramics LTCC substrates. The relationships between the electrical properties and microstructures of the resistors were discussed. Homemade resistors were printed on the Al2O3 substrates and buried in the LTCC substrates. Conductive particles of the resistors agglomerated during heat-treatment. When the conductor-agglomeration of the resistor film reached 52vol%, the agglomerated conductive particles formed a continuous linkage structure, and the resistance of the resistors showed a consistent value. When the volume frictions of the RuO2 conductive agglomeration were at values between 42 to 52vol%, the resistance of the films decreased with increasing the RuO2 agglomeration volume fractions. The RuO2 agglomerate dispersed in the glass matrix of the resistor conductor and the network of the conductive particles disappeared when the volume friction of the RuO2 agglomeration was lower than 42vol%. The results of RuO2 agglomeration volume friction vs. resistivity of the embedded resistor films matched the conduction model developed by Vest. Migration of the glass compositions between the resistor film and LTCC substrates determined the phase separation during sintering. Compositions of B2O3、SiO2 and CaO diffused from substrate to the resistor film, and the Pb2+ ion migrated from the resistor film to substrate layer. In order to made lead(Pb) free resistor paste, a glass without Pb was prepared. A lead borosilicate glass was also prepared in order to compared with lead free paste. For the resistor with leaded glass had higher resistance than that with lead-free glass. Adding TiO2 and Fe2O3 to the lead-free resistor paste, the TCR value of the resistor decreased.
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Wang, Xiaozhou. "Development of dielectric materials for low temperature co-fired ceramics (LTCC) application." Phd thesis, 2020. http://hdl.handle.net/1885/217352.
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Low temperature co-fired ceramics (LTCC) technology allows constructing three-dimensional structure of electronic components and facilitates the assembly of devices made of different types of materials and presented with different functions. The development of high performance LTCC materials is a big challenging in this field due to the limitation of the processing conditions and the selection of potential candidate materials. The controllable stability and repeatability are also critical issues. This thesis is to challenge these difficulties by conducting systematic research on the chemical composition, phase formation, structure, electrical and thermal properties of potential candidate materials to develop a series of LTCC materials with optimal performance.
In this thesis, the novel sol-gel process is introduced to prepare the amorphous phase, rather than using traditional molten glass, for better chemical composition control. Two amorphous materials, Amorphous phase-1 (AP-1) and Amorphous phase-2 (AP-2), are synthesized in the temperature range of 600oC and 700oC. The final chemical composition of AP-1 is 79.51% SiO2-0.81% Na2O-2.41% K2O-2.50% CaO-14.77% B2O3, and that of AP-2 is 80.78% SiO2-0.27% Na2O-0.87% K2O-3.45% CaO-5.25% BaO-9.38% B2O3 (mole ratio). The processing condition is optimized to reduce residual carbon and avoid crystallisation out of the amorphous phase. The controllability of low-melting chemical components in amorphous phases will reduce the sintering temperature of LTCC materials in a manageable manner.
The sol-gel derived amorphous phases are used to develop the LTCC composites with dielectric constant at different values and optimized thermal expansion property. As results, the hexagonal Al2O3 is mixed with 50.19wt% AP-1 and 46.65wt% AP-2, respectively, to form the composites which show dielectric constant of 7-8 and the coefficient of thermal expansion (CTE) of ~6ppm/oC when sintered between 850oC and 900oC for 6h. The composite made up of 60wt% monoclinic ZrO2 and 40wt% AP-1 presents dielectric constant of ~11 and CTE of ~6ppm/oC when sintered at 850oC for 0.5h. The composite with the composition of 42.86wt% AP-1+52.38wt% fused SiO2+4.76wt% Al2O3 exhibits dielectric constant of ~5 and CTE of 3.26ppm/oC when sintered at 850oC for 6h. This series of LTCC materials with adjustable dielectric constant and appropriate thermal expansion property can provide a flexibility in electronic circuit designs.
Besides the sol-gel derived amorphous phases, we also introduced a cubic KBSi2O6 phase with simpler composition as the precursor to develop the LTCC materials for the first time. Different from the amorphous phase forming vacuous liquid to densify the composites, this silicate exhibits good tolerance for ionic substitutions (such as Al substituting B), and thus lead to intimate contact of phases in the sintered sample to achieve well densified microstructure. As the result, the composition of developed sample is Al2O3: KBSi2O6: CaO=1.07: 1: 0.4 (mole ratio). It shows dielectric constant of ~8 and CTE of 11.04~12.46ppm/oC when sintered between 850oC and 900oC.
Overall, utilizing the sol-gel derived amorphous phases and unique crystalline KBSi2O6 phase as the precursors enables controllable design of LTCC materials. As the result, through systematic investigation presented in this thesis, we have developed five LTCC materials with tuneable dielectric constant in the range of 4-12. These materials show dielectric loss below 0.003 and resistivity above 10^12 ohm centimeter. The thermal expansion property is also adjusted to be in the acceptable range to match with the silicon, alumina substrates or printed circuit board. All designed LTCC materials can be co-fired with silver electrode at the temperature range of 850-900oC without any internal diffusion. Also industrial trial has been conducted by industrial collaboration partner which confirmed the validation of these LTCC materials.
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Liu, Bang-kai, and 柳邦凱. "Improvement of microwave dielectric properties of diopside-based glass-ceramics using low temperature co-fired ceramic process." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/62909385079846193909.
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碩士國立臺灣科技大學
機械工程系
101
In this study, diopside glass-ceramics (CaMgSi2O6) materials sintered in reduced atmosphere, which required a low dielectric constant (k), high quality factor (Q×f) and a near zero temperature coefficient of the resonance frequency (τf) as a microwave dielectric ceramic materials, were studied. Experimental results reveal that different size of zirconia nucleating agents added into MgO-CaO-2SiO2 system show not only increase of nucleating agents but also enhancement of crystallization in diopside glass-ceramics. Microstructural features demonstrated that large of ZrO2 nucleating agents precipitate in the matrix due to addition of nano particle size in the diopside system. Moreover, Rietveld refinement results show that specimens with nanometer ZrO2 addition reveal low amorphous content (29.33 wt%) than specimens added with micrometer ZrO2 (33.01 wt%), and activation energy of crystallization also decrease from 548 kJ/mol to 497 kJ/mol, indicating that nano nucleating agents added into diopside glass-ceramic could increase the crystallization. Therefore, quality factors increase from 9,391 GHz to 11,127 GHz due to high crystallization. Furthermore, diopside glass-ceramics added with appropriate ceramics and sintered in reduced atmosphere were also investigated. The appropriate ceramics reveal high Qxf and high positive τf, respectively. Experimental results reveal that diopside glass-ceramics added with appropriate ceramics show that appropriate ceramics addition would induce the high reactive crystallization in CaMgSi2O6 glass-ceramics. Therefore, diopside glass-ceramics added with appropriate ceramics sintered at 960oC in reduced atmosphere reveal k=9.3，Qxf=7,709 GHz and ?輎=-0.05 ppm/oC application in LTCC process.
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Huang, De-Long, and 黃得隆. "Development of Low Temperature Piezoelectric Materials and Application of Multi-layer Co-fired Ceramics." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/32123552952496543844.
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碩士國立臺灣科技大學
機械工程系
105
This paper mainly discusses the piezoelectric properties of lead-zinc-zirconium titanate titanate lead-based ceramic system through low-temperature sintering, the use of low-temperature material system to complete multi-layer piezoelectric ceramic components, and maintain a certain piezoelectric properties, and then used in the life of more Aspects of the components. Low temperature sintering to make use of materials and energy costs significantly reduced, add the appropriate amount of Li2CO3 when the use of combustion agent, and explore the different components of the ferroelectric, piezoelectric and other characteristics, the design of excellent actuating material system. 0.3Pb(Zn1 / 3Nb2 / 3) O3 - 0.7 Pb (Zr0.52Ti0.48) O3 is added as 0.3% to 0.9wt% of Li2CO3 as the sintering agent. It can be seen from the sintering temperature and density measurement. The best content of 0.6wt% and the sintering temperature at 900 ° C for 6 hours, can get the best properties and temperature sintering, etc., will promote the sintering rate and densification, piezoelectricity test in the zinc lead niobate content (72.6%) with the largest grain size (1.82 μm), the color of which was yellowish, and the color was yellowish, And high densification can even light transmission, the relative density of up to 95% or more, of which Li + ion replacement PZNZT system of Zn2 + formed by hardening modified to form the oxygen vacancy and improve the coercive field, in the modified system (14 kV / cm), the average residual value is maintained at (40 μC / cm2) while the strain rate of the material system in the block is also quite excellent Strain (0.35%), the other advantage is high Ritual temperature (average 280 ℃) is 0.3PZNZT + (0.3 ~ 0.9) wt% Li2CO3 advantage, can overcome the yuan The work of the heat generated by the heat or high temperature of the working environment, is expected to use the components on the demand for more consistent. Multi-layer components using modified ceramic powder with the industry common slurry configuration required strip, and screen printing, stacking, cutting, sintering and other processes, the completion of the final multi-layer components, while TGA detection by the relevant sintering parameters and complete multi-layer Ceramic strip and silver electrode at 900 ℃ sintering, EDS analysis can be learned, multi-layer ceramic components in the traditional sintering found that there will be partial silver problems and leakage current situation, the use of laboratory microwave sintering furnace at the same temperature Sintering effective control of silver electrode diffusion, whether microscopic or the performance of the performance, the piezoelectric constant d33 is 440pC / N, compared with the block material decreased, in the application of 45kV / cm (270V) voltage can reach 0.2% Adaptable and successfully overcome the above problems. 0.3Pb(Zn1/ 3Nb2 / 3) O3 - 0.7 Pb (Zr0.52Ti0.48) O3 + 0.6wt% Li2CO3 After the modification, it is found that the Qm quality factor is low (about 60), and the energy and mechanical energy , Resulting in high temperature within the material, or even more than the temperature above the house, the material into a cis phase, so that the characteristics of the material decreased, so the quality factor is also a component of the importance of one of the characteristics, so hardened by Mn added to the raw material system , The material system Qm is effectively raised (to 175).
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Kang, Chun-yueh, and 康鈞岳. "Study of Lead-Free Thick-Film Resistors Embedded in Low Temperature Co-fired Ceramics." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/08124812799120515757.
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碩士義守大學
材料科學與工程學系碩士班
93
In this study, lead-free thick film resistors (TFRs) were prepared by mixing of ruthenium oxide (RuO2) and K2O-CaO-B2O3-SiO2 glass. The resistors were post-fired on alumina and co-fired in LTCC substrates. Five different metal oxides were added into the glass phase, such as Nb2O5, MnO2, MoO3, Fe2O3, TiO2, they were used as temperature coefficient of resistor (TCR) adjustment agents of the resistors. The influences of the microstructures changed and of the interactions at the interface between resistors and substrates were investigated. The volume fractions of conductor-agglomeration (RuO2) in resistor layers were influenced the electrical properties of thick-film resistors. When the volume fraction of conductor-agglomeration increased, the conductive particles became continuity, and the conductivity of TFRs increased. Glass content in the conductor-agglomeration influenced the electrical properties of the resistors after sintering. The content of glass phase in conductor-agglomeration increased with increasing dwelling time, the distances between RuO2 particles increased, and the conductivity of TFRs decreased. Five different metal oxides were added into the glass phase, such as Nb2O5, MnO2, MoO3, Fe2O3, TiO2, were used as temperature coefficient of resistor (TCR) adjustment agents. The additive made glass structure loose and conductivity of resistor decreased, the TCR values of the resistors moved toward negative direction. When adding 4wt% MnO2 into the glass phase, the thick-film resistors embedded in LTCC can get better electrical properties, the conductivity of resistor is 2.46 (Ω-cm)-1, the temperature coefficient of resistor decreased to 12 ppm/℃. During sintering, the interactions between resistors and substrates were more violent in co-fired process than in post-fired. The thick-film resistors embedded in the sintered LTCC substrates, large amount of CaO in the substrate layers diffused to the resistor layers. The diffusion behaviors of SiO2, Al2O3, MgO...etc. were not obvious.
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Yang, Ya-Chun, and 楊雅鈞. "Design and Study of Low Temperature Co-Fired Ceramics High Frequency Multilayer Chip Inductors." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/38159798942537462475.
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碩士義守大學
電機工程學系
91
This thesis studies the design and characteristics analysis of Low Temperature Co-Fired Ceramics (LTCC) high frequency multilayer chip inductors, and establishes the equivalent circuit mode of device itself. The LTCC high frequency multilayer chip inductors consist of dielectric material and coil structure, which are widely applied to mobile communication and wireless transmission application. The parameters such as the number of coil, the thickness of dielectric layer…, etc. which concerned with the electrical characteristics and the application request of electrical characteristics are further analyzed in the study. The optimum design of electrical structure is found out by the analysis of frequency response and parasitic effect between simulation and measurement that the measurement system consists of network analyzer and impedance analyzer. The studies cover present situation and development trend of LTCC material system, design roadmap and process technology. Results obtained in the thesis could be employed to integration device design, manufacturing and measurement of LTCC technology.
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Chen, Yan-ming, and 陳彥明. "Improvement of microwave dielectric properties at diopside-based glass-ceramics doped with ceramics by low temperature co-fired copper electrode process." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/83860300609882908450.
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碩士國立臺灣科技大學
機械工程系
102
In this study, diopside glass-ceramics (CaMgSi2O6) materials sintered at temperature below 1000 oC and co-fired with copper electrodes in a reducing atmosphere, which required a low dielectric constant (k), high quality factor (Q×f) and a near zero temperature coefficient of the resonance frequency (τf) as a microwave dielectric ceramic materials, were studied. First, in order to improve the quality factor of CaMgSi2O6 glass ceramics, configured with different molar proportions of (ZnxMg1-x)2SiO4 (x=0~1) ceramic powders, and explore its basic characteristics. According to the Mg2SiO4-Zn2SiO4 binary phase diagram the eutectic point about near x = 0.7, therefore the experimental results revealed that the densification temperature of (ZnxMg1-x)2SiO4 (x=0.6、0.7、0.8) ceramics can decrease to 1250oC. The quality factor values of (Zn0.6Mg0.4)2SiO4 can achieve nearly 45,000 GHz by sintering in air at temperature 1250 oC and 1300 oC for 2hr. Furthermore, adding different molar ratio of 10 wt% (ZnxMg1-x)2SiO4 (x=0~1) ceramic powders into CaMgSi2O6 glass ceramics to enhance the quality factor. From the experiment results, the quality factor values increased from 11,233 GHz to 13,845 GHz due to the addition of (Zn0.6Mg0.4)2SiO4 ceramics powders sintered in air at temperature 960 oC for 2hr. In order to improve the τf values to near 0ppm/oC and enhance quality factor values , CaTiO3 and (ZnxMg1-x)2SiO4 (x=0、0.6、0.7、0.8) was added to CaMgSi2O6 glass ceramics. Based on the previous studies, CaTiO3 soluted into the CaMgSi2O6 glass ceramics, so can’t improve the τf values. Experimental results showed that doped (ZnxMg1-x)2SiO4 ceramics can induce the crystallization of diopside glass-ceramics and caused CaTiO3 stability in the material system. Therefore, CaMgSi2O6 glass-ceramics added with 8wt% (Zn0.6Mg0.4)2SiO4 and 8wt% CaTiO3 ceramics sintered in reducing atmosphere at 960oC for 2hr shows excellent microwave dielectric properties : k=8.62，Qxf=11,650 GHz and ?輎=-1.2 ppm/oC . At last , CaMgSi2O6 glass-ceramics with copper electrodes were co-fired in reducing atmosphere at 960oC for 2hr and analyzed to detect interactions between the glass-ceramics and electrodes. XRD analysis revealed Cu4MgO5, Ca2CuO3, Ca2MgSi2O7, Mg2SiO4 and SiO2 secondary phases, which appears in the interface after co-firing. Due to high quality factor of Ca2MgSi2O7 and Mg2SiO4 secondary phases, it does not induce degradation in quality factor values. CaMgSi2O6 glass-ceramics doped 10wt% (Zn0.6Mg0.4)2SiO4 and 8wt% CaTiO3 ceramics with copper electrodes were co-fired in reducing atmosphere at 960oC for 2hr shows microwave dielectric properties : k=8.36，Qxf=9,061 GHz.
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Wu, Po-Hsien, and 吳柏賢. "Dielectric properties of diopside-based glass-ceramics and diffusion effect of the co-fired silver electrode." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/77168980067425345912.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
105
Microwave dielectric ceramic materials play an important role in the wireless communications and portable devices, such as global positioning systems (GPS) and mobile phones. This study focuses on a novel microwave dielectric material - diopside (CaMgSi2O6) glass-ceramic. Diopside material has a unique character of low dielectric constant (k), low cost, high quality factor (Q*f value) and lower than 900℃ sintering temperature. Therefore, diopside is a potential candidate material for LTCC (Low Temperature Co-fired Ceramic) process. However, the large temperature coefficient of resonance frequency (τf), -60ppm/℃, is unstable to be applied in microwave dielectric components. In this case, ZnTiO3 was chosen to compensate the large negative temperature coefficient of resonance frequency (τf) of diopside glass-ceramics. Followed by this result, the microstructure analysis and electrode inhibition after co-fired with silver electrode were carried out by SEM-EDS in this work. In the first part of this research, different ratio of ZnTiO3 powder were added into diopside glass-ceramic and the heat treatment were carried out at 825~900℃ for 2 hours. In the beginning, specimens were unable to be densified at 825℃. As increasing heat treatment temperature, the specimens can be densified, from 850℃~ 900℃. Simultaneously, some silicate and titanate secondary phases with excellent microwave dielectric properties were formed, such as (Zn(1-x)Mgx)SiO4 with low dielectric constant and (Zn(1-x)Mgx)TiO3 with positive τf.. Therefore, the microwave dielectric properties of diopside material can be improved by these secondary phases. Finally, the optimal ratio is diopside with 30wt% ZnTiO3 addition, which contains the following key characteristics: k=9.2, Q*f=8232GHz, τf = -17.7ppm/℃ Electrode diffusion usually makes serious damages for components in changing the frequency unexpectedly and overall efficiency of components. Generally, silver ions are oxidized easily then diffuse into diopside glass-ceramics substrate during sintering process. To avoid the phenomena of silver diffusion, a sintering mechanisms without atmosphere control was used. According to references, ceramic phases or amorphous silica are used as both ways can inhibit the electrode diffusion efficiently. As demonstrating in previous chapter, some ceramic phases, silicate or titanate secondary phases, have been formed after adding ZnTiO3 during sintering process, the amorphous silica was chosen to inhibit silver diffusion in this research. Nanoscale amorphous silica forms quartz phase in sintering process around 700℃, and the quartz will become a obstacle for silver diffusion. The efficiency of diffusion effect can be measured by using sem-eds linescan. In conclusion, the optimal solution is to add 4wt% amorphous silica, which diminishes the diffusion effect of silver ions significantly.
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Wu, Syu-Sheng, and 吳旭昇. "Multi-Band Integrated Antennas and Diplexers on Printed Circuit Boards and Low Temperature Co-fired Ceramics (LTCC) Filter." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/38841288599840833854.
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碩士國立交通大學
電信工程系所
93
The integrated RF front-end module of communication systems usually only includes a diplexer and two different bandpass filters. As the RF front-end module becomes highly integrated, the integrated design of a dual-band antenna and a diplexer will be in great trends for research and commercial products in the future. In the paper, Ansoft HFSS full wave simulator is used to be the design tool. The purpose of this paper is to propose a new integration design of a dual-band antenna and a diplexer that can be applied to the Wireless Local Area Network (WLAN) system. The dual-band antenna structure proposed by this paper is constructed by the original quarter wavelength (��/4) monopole antenna plus a sleeve structure. This improvement is expected to help obtain the wide bandwidth and dual-band effect. The diplexer is composed of stepped impedance resonator bandpass filter and ��/4 parallel coupled microstrip line bandpass filter. The proposed dual-band antenna structure possesses 22.49% and 32.58% impedance bandwidth under the WLAN band of 2.4 GHz and 5 GHz. The proposed integrated structures of the dual-band antenna and the diplexer can meet the requirements of the 2.4 GHz and 5.2 GHz WLAN systems. Besides, in order to obtain a WLAN bandpass filter with the specific of 2.4GHz, we apply LTCC to effectively process the selected suitable lumped element circuit model of the bandpass filter. The newly designed WLAN bandpass filter will be of small size, of high selectivity and highly integrated.
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Chou, Yien-Tien, and 周晏田. "Two kinds of innovative magnetic near-field probes fabricated in low temperature co-fired ceramics for electromagnetic interference detection." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/kt2c7s.
Full textAbstract:
博士國立臺灣大學
電子工程學研究所
101
With increasing operation speed, ever-complicated circuit structure, and dense packaging, electromagnetic interference (EMI) problem of electronic products becomes more and more serious. In general, EMI generation can be viewed as three parts: interference source, interfering path, and radiation antenna. To effectively suppress EMI, finding out the interference sources and eliminating them are always the most efficient and low-cost solution. In modern electronic products, most interference sources are caused by the rapid switching current of the integrated circuits (ICs). International Electrotechnical Commission (IEC) defines the IEC 61967 standard series to rapidly and accurately detect this kind of emission sources. The third and sixth parts of this standard series introduce the electromagnetic near-field (NF) measurement method. The detailed electromagnetic field distribution related to the voltage and current flowing paths over the surface of the IC device under test (DUT) can be obtained using this NF scanning method. Electrical engineers can debug the EMI according to the information of the field distribution. NF probe is the key component of the surface field scan method. Therefore, we review the previous papers concerning the NF probes and discuss their characteristics. They are mainly typed as electrical and optical probes, and then we further propose two kinds of innovative electrical probe structures in this dissertation. Firstly, several new types of low-cost and robust single-ended magnetic NF probes fabricated in low temperature co-fired ceramics (LTCC) are presented. Parallel C-shaped strips and its variations are inserted into the loop area in the front end of probes to achieve common-mode high-pass and notch filters for electric-field noise suppression. These probes with this kind of filter have excellent wideband electric field suppression. They are named as high electric field suppression (HEFS) probes type A~D. The size of loop aperture in all probes is 100 μm long and 400 μm wide. The signal received from the loop is routed to a measurement apparatus through a semi-rigid coaxial cable with outer diameter of 0.047 in. The flip-chip junction with low loss and good shielding is used between the probe head in LTCC and the semi-rigid coaxial cable. We take the probes over a 2000-μm-wide microstrip line as DUT to measure the probe characteristics. The isolation between electric and magnetic fields for a reference probe based on an old design using the same LTCC process is better than 30 dB from 0.05 to 12.65 GHz. Proposed type A probe has two parallel C-shaped strips, and it has better isolation of 35 dB from 0.1 to 11.05 GHz. Type C has one end of its strip shorted to ground, its 30 dB isolation frequency range can be extended to 0.05~17.8 GHz. With additional layout variation in type D, isolation can be improved to 40 dB up to 10.9 GHz. The spatial resolution for these probes is 140 μm when the distance between the metal surface of the microstrip line and the nearest edge of the loop is held at 120 μm. The calibration factors (CFs) of the proposed probes are only slightly increased as compared with reference probe. Secondly, to achieve good spatial resolution, small loop size is required in the traditional loop probe. However, the smaller loop size will lead to the lower sensitivity for the probe. In addition, loop size is always limited by the minimum line spacing of the fabrication process. Another problem is that the asymmetric electric field coupling into a probe will not be canceled perfectly even if the structure of this probe is symmetric. To circumvent these problems, the space difference magnetic NF probe with three kinds of spatial resolutions is proposed in this dissertation. The probe head including a single-turn loop and a two-turn loop is also manufactured in LTCC. The single-turn loop is clamped with the two-turn loop. Two loops are covered with two shielding ground plates to form a tri-plate structure. The received signals from these two loops are outputted with two SMA connectors through two striplines. In the same way, the flip-chip junction is used between the probe head and the striplines for assembly. The probe characteristics are measured using a 436-μm-wide microstrip line with impedance of 50 Ω. Two output ports have different spatial resolutions because two different loops are located above the microstrip line at different heights. The space difference probe will have higher spatial resolution when the received signals are outputted in difference. In comparison with one smaller double-loaded probe whose resolution is comparable to that of this difference output of the proposed probe by EM simulation, the proposed spatce difference probe can suppress the side electric field coupling well by the difference operation because two loops receive approximate electric field simultaneously.
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Chen, Tai-How, and 陳泰豪. "Low-Temperature co-fired dielectric-magnetic ceramic composite." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/73213732103183175512.
Full textAbstract:
碩士國立成功大學
資源工程學系碩博士班
95
Recently, composite materials with both superior dielectric and magnetic properties can be used to produce a low cost and high performance L/C EMI filter for high frequency application. Therefore this composite material had attracted much attention. A high dielectric constant material, Bi-added BaO-Nd2O3-4TiO2, was chosen as the raw material for the present work. Moreover, a glass system was selected to be added to Bi-added BaO-Nd2O3-4TiO2 system to decrease the sintering temperature. The effects of various glasses addition on both the sintering behavior and dielectric properties were investigated. The results revealed that BNBT (BaO．(Nd0.8Bi0.2)2O3．4TiO2) with 20wt% BB25SZ (B-Bi-Si-Zn glass) could be densified at 900oC for 2h, which possess excellent dielectric properties. Furthermore, the above dielectric was mixed with different amount of NiCuZn ferrites to form dielectric-magnetic composites. With appropriate glass addition, the composites sintered at 900oC for 2h exhibited both superior dielectric and magnetic properties.
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Yu-YingHsiao and 蕭裕穎. "Low Temperature Co-Fired Ceramic Micropumps with Conical Diffuser Valves." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/39075429913898002421.
Full textAbstract:
碩士國立成功大學
機械工程學系碩博士班
98
In this study, the investigation of the low temperature co-fired ceramic micropumps with conical diffuser valves and with pockets conical diffuser valves were designed and manufactured. The diaphragms of micropumps also used low temperature co-fired ceramic, so that the micropumps could be combined with diaphragms. Therefore, the reliability of micorpumps will be enhanced. Also, by applying the Genetic Algorithms and Computational Fluid Dynamics program FluentTM, the design optimization of the conical diffuser valves with pockets is automated. The obtained results of optimization show that the rectification efficiency will increase when the positions of the pockets approach the throat and the suitable pockets radius. The best rectification efficiency of 26.78% is obtained from the conical diffuser valves with pockets, and 5.51% more than the conical diffuser valves without pockets . Moreover, we used the parameters to design the low temperature co-fired ceramic micropumps with pockets conical diffuser valves. According to the experiment results, low temperature co-fired ceramic micropumps with pockets conical diffuser valves exhibited a better net volumetric flow rate and higher optimal actuation frequency than the low temperature co-fired ceramic micropumps without pockets conical diffuser valves when the back pressure is zero. When the drive voltage is 150 Vpp, the actuation frequency is the optimal frequency of different types of valves. When working fluid is deionized water and alcohol, the maximum net flow rate of the low temperature co-fired ceramic micropumps with pockets conical diffuser valves increased 20.45 % and 12.89 %, respectively. Whether the working fluid is deionized water or alcohol is in a similar Roshko range, a better performance will be displayed.
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Wang, Yu-Ting, and 王俞婷. "Effects of Mg4Nb2O9 Ceramic Dielectric Modify Agent in Low Temperature Co-fired Ceramic Tape." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/67260512866183725268.
Full textAbstract:
碩士國立交通大學
材料科學與工程系所
94
In this study, two commercial glass, ZnO–B2O3–SiO2 (NEG Ltd., GP5210) and B2O3–SiO2 (NEG Ltd., GA50), were used to improve the sintering and dielectric property of Mg4Nb2O9 ceramic. The interaction between GP5210 and Mg4Nb2O9 resulted in the crystallization phase and superlattice structure. Further investigations indicated that the superlattice structure had greatly contributed to the microwave dielectric property. The optimized microwave dielectric properties of Mg4Nb2O9 /80wt % GP5210 were εr = 6.63, Q = 2855.9(9 GHz), τf = -16.72 ppm/℃.Compared to GP5210 / Mg4Nb2O9, there was no interaction between GA50 and Mg4Nb2O9. The optimized microwave dielectric properties of Mg4Nb2O9 / 80wt%GA50 were εr = 4.45，Q = 1788.4(9 GHz) ，τf = -16.89 ppm/℃. The optimized microwave dielectric properties of the LTCC Tape for B2O3–SiO2 glass system were εr = 4.253，Q = 12388.3 (15 GHz), and for ZnO–B2O3–SiO2 glass system were εr = 6.627, Q=19531.5 at 15GHz by Open Reasonator. The low-temperature sintering tape had appreciate dielectric properties, therefore, were suitable for LTCC application.
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AdbulGhaffar, Farhan. "Design of LTCC Based Fractal Antenna." Thesis, 2010. http://hdl.handle.net/10754/133211.
Full textAbstract:
The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications.
The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.
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Huang, Wei Te, and 黃威特. "Study on Low Temperature Co-fired Ceramic Ba2Ti9O20 Microwave Dielectric Materials." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/32368631757701562687.
Full text
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Tu, Tui-ting, and 涂瑞庭. "Study on dielectric materials of the low temperature co-fired ceramic." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/35346761560732185889.
Full textAbstract:
碩士義守大學
材料科學與工程學系碩士班
93
In order to develop the thick film dielectric materials on the low temperature co-fired ceramic substrate, the effects of B2O3 - SiO2- CaO - Al2O3 (BSCA) glass and lithium fluoride (LiF) addition on the sintering behavior and the dielectric properties of BaTiO3 (BT) were investigated. And finding the best composition and sintering condition of the BaTiO3. In the present study, two liquid-phase sintering aids, BSCA glass and LiF were added into barium titanate to reduce its sintering temperature. The densification rate and dielectric properties of barium titanate was significantly enhanced as the sintering temperature was raised above 745℃, the melting point of BSCA glass. The relative density is reduced by the increasing addition of the BSCA glass, but the addition of 30 wt% BSCA glass in the BT ceramic obtained the worst relative density(＜70%). The relative density is enhanced by the addition of the LiF in the BT ceramic. The addition of the BSCA glass could lower the sintering temperature of BaTiO3. However, the BSCA glass reacted with BaTiO3 to form BaTiSiO5, Ba2TiSi2O8, and Ba2Al2B8O17. The dielectric constant of the reaction phases was low so that dielectric property of sintered BaTiO3 was thus degraded. The addition of 10 wt% BSCA glass in the BT ceramic obtained the best dielectric constant is about 401 when sintered at 1000℃. Because of the the addition of LiF can inhibit lower dielectric constant reaction phases and reduse the Curie temperature, the dielectric constant is enhanced by the increasing addition of the LiF. The Q value is enhanced by the increasing addition of the BSCA glass at the temperature below 900℃, the addition of 30 wt% BSCA glass in the BT ceramic obtained the best Q value is about 527. The Q value is enhanced by the addition of the LiF when sintered at 850℃, the addition of 30 wt% BSCA glass and 1 wt% LiF in the BT ceramic obtained the best Q value is about 690.But the Q value is reduced by the increasing addition of the LiF as the sintering temperature was raised above 900℃. The relative density, dielectric constant and Q value is reduced by the increasing addition of the B2O3 , because there was too many voids in the sample so that dielectric properties of sintered BaTiO3 was thus degraded.
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Hung, Jian Luen, and 洪健倫. "Compact Stub-type Bandpass Filters with Low-Temperature Co-Fired Ceramic Process." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05941539976858205345.
Full textAbstract:
碩士長庚大學
電子工程學系
98
The purpose of this thesis is to design miniaturized stub-type microstrip bandpass filters. A novel vertical inter connection in multi-layer structure is proposed that will allow us to fold the filter in half. The fabrication process of Low-Temperature Co-fired Ceramic (LTCC) is exploited for filter realization. The research results can be used in modern communication system applications for size reduction. Stub-type microstrip bandpass filters can provide wide bandwidth, controllable transmission zeros, raised attenuation rate, and good frequency selectivity. Thus, this thesis adopts stub-type microstrips as the basic structures for bandpass filter design. Circuits with light, thin, short, and small features are highly required in modern communication system. In recent years, various approaches in the stub-type microstrip bandpass filters based on the LTCC process are proposed and are highly noticed in international literatures. The LTCC process can have advantages of three-dimensional scheme, high integrity, and a small size. According to the aforementioned, this thesis is divided into three stub-type bandpass filter designs: (1)The development of vertical inter connection structure with good performance, which can be used in folded filter design to reduce its size. A LTCC vertically folded bandpass filter is designed to reduce filter size by 50%. (2)Moreover, the capacitively loaded structure is adopted to further reduce stub length of filters. An experimental bandpass filter is fabricated and operated at 5.8 GHz, which can have a length reduction of 30%. (3)This thesis proposes stepped-impedance-stub structures to synthesize a dual-band filter operated at 2.4/5.8 GHz. The good dual-band performance and compact size are achieved simultaneously. Several experimental bandpass filters are fabricated and measured, which show good performance as expected, and can be used for modern communication system applications.
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Chi-MoHuang and 黃繼模. "Fabrication of Microfluidic Devices using Low Temperature Co-Fired Ceramic Tape Technology." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/74583452961183284311.
Full textAbstract:
博士國立成功大學
機械工程學系
102
Applying low temperature co-fired ceramic (LTCC) tape technology on constructing 3-D microfluidic devices has drawn increasing attention in recent years. In the current research, a valveless micropump and a fully integrated micro-scale fuel reformer over Pt catalyst were fabricated and developed using LTCC tape technology. In addition to the detailed fabrication process, the performance of these two microfluidic devices was simulated in multiple programs and then carefully examined in experiments. These microfluidic devices were further optimized and the improved performance was demonstrated in experiments. In the valveless micropump, individual components of micropump including fluidic channels, diaphragm, chamber and planar diffuser valves were integrated in one LTCC module. Geometries of these components were designed based on numerical analysis that finite element analysis was used to characterize the displacement of a piezoelectric actuator whereas computational fluid dynamics was applied to design the planar diffuser. Performance of the designed micropump was carefully examined in experiments and the experimental data echoed the numerical analysis and revealed that the performance of a micropump was significantly improved by adding a pair of pockets near the neck of diffuser. In the micro-reformer, the microfluidic channels and Pt catalyst was integrated with a LTCC reformer by direct co-firing with no additional process. Current study compared the effect of different thicknesses of Pt catalyst (10 and 40 nm) in LTCC reformers. As a source of hydrocarbon, methanol was used and the production of hydrocarbon fuels including hydrogen, carbon monoxide and methane was measured by gas chromatography. Among different parameters tested, our results revealed that LTCC reformer coated with 10-nm Pt catalyst generated most hydrocarbon fuels at a flow rate of 1 ml/h and at temperature of 300 °C. Overall, the simulated results by finite element analysis and computational fluid dynamics, used in the current study showed good predictability as demonstrated in experimental results, which suggest that these simulations are feasible in designing and characterizing microfluidic devices prior to manufacturing processes. Moreover, LTCC tape technology is a simple and reliable method to fabricate microfluidic devices with heat-resistance, corrosion-resistance, air-tightness, full integration and high reliability.