Добірка наукової літератури з теми "Bonding ratio"

In this study, through an analysis of vibration response characteristics of joint surface stiffness on dangerous rock mass, the relationship formula between amplitude ratio of the dangerous rock mass to the bedrock and the length of the bonding section of the joint surface is determined. The stability of the rock mass can be evaluated by combining the formula with the existing rock-mass limit equilibrium theory. This study proposes the existence of a resonance bonding length for the dangerous rock mass. When the length of the bonding section reaches the resonance bonding length, the dangerous rock mass has the largest response to the bedrock vibration. The study found that when the length of the bonding section of the dangerous rock mass is longer than the resonance bonding length, the amplitude ratio increases with the decrease of the bonding section and increases with the increase of the vibration frequency of the bedrock. When the length of the bonding section of the dangerous rock body is shorter than the resonance bonding length, the amplitude ratio decreases with the decrease of the bonding section and decreases with the increase of the vibration frequency of the bedrock. Indoor experiments were conducted by collecting the vibration time-history curves of rock blocks and stone piers and performing analysis and calculation, which proved the accuracy of the analytical results. Through the amplitude ratio of the dangerous rock mass and the bedrock, the bonding length can be calculated. This method can improve the calculation accuracy of the stability coefficient K of the dangerous rock mass.

Ultra-pure copper sputtering target is a key material widely used in large-scale integrated circuits with 90-28 nm feature size. The copper target for 300 mm integrated circuit requires a reliable diffusion bonding between the ultra-pure copper target and the copper alloy backplate. The bonding ratio and bonding strength of diffusion bonding should reach over 99% and 80 MPa respectively. In this paper, the ascendant structure of electron beam welding united diffusion bonding with high quality was designed. The ultra-pure copper target and the C18000 copper alloy backplate were machined to coordinating size, meanwhile the backplate underwent surface treatment of toothed/smooth, ion cleaning, magnetron sputtering coating, then the combination of target and the backplate was proceeded electron beam welding and diffusion bonding. Metallographic microscope, scanning electron microscope (SEM), mechanical tensile machine, C-scan flaw detector were used to analyze the bonding properties including interface microstructure, bonding strength and bonding ratio. The results show that the bonding ratio of copper target was above 99%, and the bonding strength was up to 80-160 MPa.

Due to the acceptable high-temperature deformation resistance of Inconel 718, its welding parameters such as bonding temperature and pressure are inevitably higher than those of general metals. As a result of the existing punitive processing environment, it is essential to control the deformation of parts while ensuring the bonding performance. In this research, diffusion bonding experiments based on the Taguchi method (TM) are conducted, and the uniaxial tensile strength and deformation ratio of the experimental joints are measured. According to experimental data, a deep neural network (DNN) was trained to characterize the nonlinear relationship between the diffusion bonding process parameters and the diffusion bonding strength and deformation ratio, where the overall correlation coefficient came out to be 0.99913. The double-factors analysis of bonding temperature–bonding pressure based on the prediction results of the DNN shows that the temperature increment of the diffusion bonding of Inconel 718 significantly increases the deformation ratio of the diffusion bonding joints. Therefore, during the multi-objective optimization of the bonding performance and deformation of components, priority should be given to optimizing the bonding pressure and duration only.

In this study, conditions of metallurgical bonding between steel and aluminum in cold forging process is investigated. Two-layered cylindrical cup of the materials is produced in cold backward extrusion in five processing velocity conditions. Small tensile test specimens are cut off at the bonding boundary in the product using a wire-cutting machine and the bonding strength on the boundary is measured in tensile test using the specimens. Fractured contact surfaces are observed with an electron microscope for investigation of bonding. Finite element analyses for the backward extrusion are conducted and surface expansion ratio and interface pressure on the boundary are calculated. The influence of process conditions, extrusion velocity and surface expansion ratio and boundary pressure, on the bonding are investigated.

Bonding wires made of aluminum are the most used materials for the transmission of electrical signals in power electronic devices. During operation, different cyclic mechanical and thermal stresses can lead to fatigue loads and a failure of the bonding wires. A prediction or prevention of the wire failure is not yet possible by design for all cases. The following work presents meaningful fatigue tests in small wire dimensions and investigates the influence of the R-ratio on the lifetime of two different aluminum wires with a diameter of 300 µm each. The experiments show very reproducible fatigue results with ductile failure behavior. The endurable stress amplitude decreases linearly with an increasing stress ratio, which can be displayed by a Smith diagram, even though the applied maximum stresses exceed the initial yield stresses determined by tensile tests. A scaling of the fatigue results by the tensile strength indicates that the fatigue level is significantly influenced by the strength of the material. Due to the very consistent findings, the development of a generalized fatigue model for predicting the lifetime of bonding wires with an arbitrary loading situation seems to be possible and will be further investigated.

In order to solve the problem of the instability of the layered hollow spherical structure caused by the epoxy bonding layer cracking, peeling and destruction, an exact analytical solution of the multi-layered hollow sphere with epoxy bonding layer under point load is obtained. The influence of the epoxy bonding layer change on the stress of the layered hollow sphere is studied by using the methods of analytical solution and numerical calculation. Numerical calculation results show that the stress of the bonded layered structure is affected by the Young’s modulus, Poisson’s ratio and the thickness of the bonding material without changing the overall size of the bonded layered hollow spheres. The use of the bonding materials can cause stress concentration at the bonding material interface. And the increase of Young’s modulus and the thinning of thickness of the bonding material can reduce the stress at the interface between the epoxy bonding layer and the outer layer. Moreover, the change of Poisson’s ratio of the bonding material cannot substantially reduce the interface stress. The research results provide theoretical guidance for the material selection and thickness setting of the bonding layer for layered hollow sphere.

In the present study, the hot roll bonding process of 7000 series aluminum alloy laminated materials was numerically simulated and investigated using the finite element method, and the process parameters were experimentally verified by properties testing and microstructure analysis after hot roll bonding. In the roll bonding process of aluminum alloy laminated materials, the effects of the intermediate layer, pass reduction ratio, rolling speed and thickness ratio of component layers were studied. The results of finite element simulations showed that the addition of a 701 intermediate layer in the hot roll bonding process could effectively coordinate the deformation of the 705 layer and 706 layer and prevented the warping of the laminated material during hot rolling. It is recommended to use a multi-pass rolling process with small deformation and high speed, and the recommended rolling reduction ratio is 20%~30%, the hot rolling speed is 1.5~2.5 m/s and the thickness ratio of the 705 layer and 706 layer is about 1:5. Based on the above numerical results, five-layer and seven-layer 7000 series aluminum alloy laminated materials were prepared by the hot roll bonding process. The results showed that metallurgical bonding was realized between each component layer, and no delamination was observed from the tensile fracture between the interfaces of component layers. The tensile strength of the prepared laminated materials decreased with the increase in the thickness ratio of the 705 layer, and the bonding strengths of the laminated materials were in the range of 88–99 MPa. The experimental results verified the rationality of the process parameters recommended by the numerical simulations in terms of warping and delamination prevention.

For mobile electronics such as Smartphones, Smartcards or wearable devices there is a trend towards an increasing functionality as well as miniaturisation. In this development Micro Electro- Mechanical Systems (MEMS) are an important key element for the realisation of functions such as motion detection. The specifications given by such devices together with the limited available space demand advanced packaging technologies. The 3D-Wafer Level Packaging (3D-WLP) enables one solution for a miniaturised MEMS package by using techniques such as Wafer Level Bonding (WLB) and Through Silicon Vias (TSV). This technology increases the effective area of the MEMS device by elimination dead space, which is typically required for other approaches based on wire bond assembly. Within this thesis, different TSV technology concepts with respect to a 3D-WLP for MEMS have been developed. Thereby, the focus was on a copper based technology as well as on two major TSV implementation methods. This comprises a Via Middle approach based on the separated TSV fabrication in the cap wafer as well as a Via Last approach with a TSV implementation in either the MEMS or cap wafer, respectively. For each option with its particular challenges, corresponding process modules have been developed. In the Via Middle approach, the wafer-related etch rate homogeneity determines the TSV reveal from the wafer backside Here, a reduction of the TSV depth down to 80 μm is favourable as long as the desired Cu-thermo-compression bonding (Cu-TCB) is performed before the thinning. For the TSV metallisation, a Cu electrochemical deposition method was developed, which allows the deposition of one redistribution layer as well as the bonding patterns for Cu-TCB at the same time. In the Via Last approach, the TSV isolation represents one challenge. Chemical Vapour Deposition processes have been investigated, for which a combination of PE-TEOS and SA-TEOS as well as a Parylene deposition yield the most promising results. Moreover, a method for the realisation of a suitable bonding surface for the Silicon Direct Bonding method has been developed, which does not require any wet pre treatment of the fabricated MEMS patterns. A functional MEMS acceleration sensor as well as Dummy devices serve as demonstrators for the overall integration technology as well as for the characterisation of electrical parameters
Im Bereich mobiler Elektronik, wie z.B. bei Smartphones, Smartcards oder in Kleidung integrierten Geräten ist ein Trend zu erkennen hinsichtlich steigender Funktionalität und Miniaturisierung. Bei dieser Entwicklung spielen Mikroelektromechanische Systeme (MEMS) eine entscheidende Rolle zur Realisierung neuer Funktionen, wie z.B. der Bewegungsdetektion. Die Anforderungen derartiger Bauteile zusammen mit dem begrenzten zur Verfügung stehenden Platz erfordern neuartige Technologien für die Aufbau- und Verbindungstechnick (engl. Packaging) der Bauteile. Das 3D-Wafer Level Packaging (3D-WLP) ermöglicht eine Lösung für eine miniaturisierte MEMS-Bauform unter Nutzung von Techniken wie dem Waferlevelbonden (WLB) und den Siliziumdurchkontaktierungen (TSV von engl. Through Silicon Via). Diese Technologie erhöht die effektive aktive Fläche des MEMS Bauteils durch die Reduzierung von Toträumen, welche für andere Ansätze wie der Drahtbond-Montage üblich sind. In der vorliegenden Arbeit wurden verschiedene Technologiekonzepte für den Aufbau von 3D-WLP für MEMS erarbeitet. Dabei lag der Fokus auf einer Kupfer-basierten Technologie sowie auf zwei prinzipiellen Varianten für die TSV-Implementierung. Dies umfasst den Via Middle Ansatz, welcher auf der TSV Herstellung auf einem separaten Kappenwafer beruht, sowie den Via Last Ansatz mit einer TSV Herstellung entweder im MEMS-Wafer oder im Kappenwafer. Für beide Varianten mit individuellen Herausforderungen wurden entsprechende Prozessmodule entwickelt. Beim Via Middle Ansatz ist die Wafer-bezogene Ätzratenhomogenität des Siliziumtiefenätzen entscheidend für das spätere Freilegen der TSVs von der Rückseite. Hier hat sich eine Reduzierung der TSV-Tiefe auf bis zu 80 μm vorteilhaft erwiesen insofern, das Kupfer-Thermokompressionsbonden (Cu-TKB) vor dem Abdünnen erfolgt. Zur Metallisierung der TSVs wurde ein Cu Galvanikprozess erarbeitet, welcher es ermöglicht gleichzeitig eine Umverdrahtungsebene sowie die Bondstrukturen für das Cu-TKB zu erzeugen. Beim Via Last Ansatz ist die TSV Isolation eine Herausforderung. Es wurden CVD (Chemische Dampfphasenabscheidung) Prozesse untersucht, wobei eine Kombination aus PE-TEOS und SA-TEOS sowie eine Parylene Beschichtung erfolgversprechende Ergebnisse liefern. Des Weiteren wurde eine Methode zur Erzeugung bondfähiger Oberflächen für das Siliziumdirektbonden erarbeitet, welche eine Nass-Vorbehandlung des MEMS umgeht. Ein realer MEMS-Beschleunigungssensor sowie Testaufbauten dienen zur Demonstration der Gesamtintegrationstechnologie sowie zur Charakterisierung elektrischer Parameter

Le traitement des sols, notamment par des liants hydrauliques ou de la chaux, est une technique très répandue pour améliorer les caractéristiques mécaniques d'un sol de qualité insuffisante. Après leur construction, les ouvrages en sols traités sont soumis à des sollicitations environnementales qui peuvent potentiellement altérer les effets du traitement, et donc conduire à la dégradation de la performance du sol traité. Dans ce contexte, l'objectif de la thèse est d'étudier l'impact de l'accumulation de cycles hydriques sur le comportement mécanique d'un sable traité au ciment. Une méthodologie multi-échelles et multi-physiques a été mise en place pour comprendre et quantifier la dégradation du comportement mécanique macroscopique des sables traités au ciment au cours de cycles de séchage/humidification. La caractérisation mécanique à court terme du sable a été réalisée en menant une campagne d'essais triaxiaux. Le taux de liaison défini à partir de la dilatance du sol traité, a été introduit pour apprécier la mobilisation puis la dégradation des liaisons cimentaires au cours des essais triaxiaux. Afin de caractériser la durabilité du sable traité, l'impact de deux types de cycles hydriques d'intensité variable a été considéré. À la suite des cycles, des essais triaxiaux ont été réalisés constituant une base de données de 130 résultats d'essais. Le suivi du taux de liaison a permis de quantifier explicitement la dégradation des éprouvettes cimentées en fonction du type et du nombre de cycles. Les cycles hydriques ont pour effet principal d'altérer les liaisons cimentaires et donc de diminuer les performances mécaniques. Cette altération dépend du dosage en ciment mais aussi de l'intensité des cycles. Les cycles de type I conduisent à une dégradation plus importante que les cycles de type II. La cinétique de l'altération ainsi que son ampleur dépendent du dosage de ciment. L'investigation des processus intervenant à l'échelle microscopique après 24 cycles des 2 types de cycles via des observations microscopiques (MEB et MET) et des analyses physico-chimiques (DRX et ATG) a mis en évidence des transformations minéralogiques intenses dont la carbonatation des phases cimentaires à divers degrés selon l'intensité du cycle ainsi que la formation d'aiguilles d'ettringite dans la porosité. Pourtant, au niveau du comportement macromécanique, une stabilisation des performances mécaniques après une diminution modérée (-20 à -30% du déviateur) a été observée après 12 cycles hydriques. Cette approche a permis de montrer que décrire les transformations minéralogiques pour décrire la durabilité n'est pas suffisant. Il est nécessaire d'évaluer la contribution de chaque phase dans la résistance puisque des transformations minéralogiques intenses ne sont pas synonymes de fortes dégradations des sols traités. Une loi de comportement pour modéliser le comportement déviatorique observé du sable traité a été proposée en combinant le Hardening Soil Model pour la partie pré-pic et une fonction sigmoïde inverse pour la partie post-pic. Cette approche a montré une bonne précision pour simuler le comportement et notamment le radoucissement des sols traités à des pressions de confinement supérieures à 50 kPa car dans ce cas une fonction exponentielle est probablement plus adaptée pour décrire le comportement post-pic. De plus, l'optimisation a permis de déterminer les valeurs les plus adéquates pour 5 paramètres du modèle (ψ, Rf, m, λ et ecrit) en fonction du dosage en ciment. La modélisation a permis de compléter l'étude expérimentale et apporter une réflexion sur la manière de simuler le comportement post-pic. Cette étude a permis une quantification mécanique à partir d'observations macroscopiques couplée à une quantification physico-chimique des différents processus se produisant lors de cycles hydriques. Un cadre conceptuel permettant de prendre en compte l'effet de la cimentation dans le comportement des sols traités a été proposé
Soil treatment, especially with hydraulic binders or lime, is a widespread technique to improve the mechanical characteristics of poor-quality soils. After their construction, engineering structures are subjected to environmental solicitations that can potentially alter the effects of the treatment, and thus lead to the degradation of the performance of the treated soil. In this context, the objective of this thesis was to study the impact of the accumulation of hydric cycles on the mechanical behaviour of a cement-treated sand. A multi-scale and multi-physics methodology was set up to understand and quantify the degradation of the macroscopic mechanical behavior of cement-treated sands during drying/wetting cycles.Short-term mechanical characterization of the sand was performed by conducting a triaxial testing campaign. The bonding ratio, η_bondmax, defined according to the stress-dilatancy theory, was introduced to assess the mobilization and the degradation of cementitious bonds during the triaxial tests. In order to characterize the durability of the treated sand, the impact of two types of hydric cycles of different intensity was evaluated. Following the cycles, triaxial tests were performed constituting a database of 130 test results. The bonding ratio monitoring allowed to explicitly quantify the degradation of the cemented specimens as a function of the type and number of cycles. The main effect of the hydric cycles is to alter the cementitious bonds and subsequently to decrease the mechanical performances. This alteration depends on the cement content but also on the intensity of the cycles. Type I cycles lead to a more important degradation than type II cycles. The kinetics of the alteration as well as its extent depend on the cement content.The investigation of the processes occurring at the microscopic scale after 24 cycles of the two types via microscopic observations (SEM and TEM) and physicochemical analyses (XRD and GTA) has highlighted intense mineralogical transformations including carbonation of the cementitious phases to various degrees depending on the intensity of the cycle as well as the formation of ettringite needles in the pore-space. However, in terms of macromechanical behaviour, a stabilization of mechanical performance after a moderate decrease (-20 to -30% of the deviatoric stress) was observed after 12 hydric cycles. This approach has shown that relating mineralogical transformations to durability is not sufficient. It is necessary to evaluate the contribution of each phase to the strength since intense mineralogical transformations are not necessarily associated with strong degradation of the treated soils.A constitutive law to model the observed deviatoric behaviour of treated sand was proposed by combining the Hardening Soil Model for the pre-peak hardening and an inverse sigmoid function for the post-peak softening. This approach showed a satisfactory accuracy to simulate the behaviour and in particular the softening of treated soils under relatively high confining pressures. Under low confining pressures an exponentially decreasing function was however more suitable. In addition, parameters optimization determined the most appropriate values for 5 model parameters (ψ, Rf, m, λ, and ecrit) as a function of cement content. The modeling permitted to complete the experimental study and broughtsome reflexions on the way to simulate the post-peak behaviour.This study allowed a mechanical quantification from macroscopic observations coupled with a physicochemical quantification of the various processes occurring during hydric cycles. A conceptual framework allowing to take into account the effect of cementing in the behaviour of treated soils was proposed

The purpose of this diploma theses is to demonstrate the comprehensive view on the "financial health" of T-Mobile Czech Republic a.s. through the financial analysis process between year 2003 and 2007 from the position of the external user. The theoretic part of this theses is focused on the brief history, definition and principle of the financial analysis, then on users of the financial analysis and information sources for its realization including the pointing out the limitation of predicative abilities of the accounting data. Understanding of the traditional but also new methods, which are applied within the financial analysis (including the methods of intercompany comparison), is another part of the theoretic definition of the financial analysis. The practical part of the theses deals with the characteristics of T-Mobile company and with processing of the strategic analysis, which put us closer to the outside and inside surroundings of the analysed firm. It is followed by processing of the financial analysis of T-Mobile company (including comparison with its competitors), comments and evaluation of findings and results (including their comparison, where it is possible, with standard (recommended) values or with the "branch average values") and by pointing out strenghts and weaknesses of operations of the analysed company.

For mobile electronics such as Smartphones, Smartcards or wearable devices there is a trend towards an increasing functionality as well as miniaturisation. In this development Micro Electro- Mechanical Systems (MEMS) are an important key element for the realisation of functions such as motion detection. The specifications given by such devices together with the limited available space demand advanced packaging technologies. The 3D-Wafer Level Packaging (3D-WLP) enables one solution for a miniaturised MEMS package by using techniques such as Wafer Level Bonding (WLB) and Through Silicon Vias (TSV). This technology increases the effective area of the MEMS device by elimination dead space, which is typically required for other approaches based on wire bond assembly. Within this thesis, different TSV technology concepts with respect to a 3D-WLP for MEMS have been developed. Thereby, the focus was on a copper based technology as well as on two major TSV implementation methods. This comprises a Via Middle approach based on the separated TSV fabrication in the cap wafer as well as a Via Last approach with a TSV implementation in either the MEMS or cap wafer, respectively. For each option with its particular challenges, corresponding process modules have been developed. In the Via Middle approach, the wafer-related etch rate homogeneity determines the TSV reveal from the wafer backside Here, a reduction of the TSV depth down to 80 μm is favourable as long as the desired Cu-thermo-compression bonding (Cu-TCB) is performed before the thinning. For the TSV metallisation, a Cu electrochemical deposition method was developed, which allows the deposition of one redistribution layer as well as the bonding patterns for Cu-TCB at the same time. In the Via Last approach, the TSV isolation represents one challenge. Chemical Vapour Deposition processes have been investigated, for which a combination of PE-TEOS and SA-TEOS as well as a Parylene deposition yield the most promising results. Moreover, a method for the realisation of a suitable bonding surface for the Silicon Direct Bonding method has been developed, which does not require any wet pre treatment of the fabricated MEMS patterns. A functional MEMS acceleration sensor as well as Dummy devices serve as demonstrators for the overall integration technology as well as for the characterisation of electrical parameters.:Bibliographische Beschreibung 3 Vorwort 13 List of symbols and abbreviations 15 1 Introduction 23 2 Fundamentals on MEMS and TSV based 3D integration 25 2.1 Micro Electro-Mechanical systems 25 2.1.1 Basic Definition 25 2.1.2 Silicon technologies for MEMS 26 2.1.3 MEMS packaging 29 2.2 3D integration based on TSVs 33 2.2.1 Overview 33 2.2.2 Basic processes for TSVs 34 2.2.3 Stacking and Bonding 47 2.2.4 Wafer thinning 48 2.3 TSV based MEMS packaging 50 2.3.1 MEMS-TSVs 50 2.3.2 3D-WLP for MEMS 52 3 Technology development for a 3D-WLP based MEMS 57 3.1 Target integration approach for 3D-WLP based MEMS 57 3.1.1 MEMS modules using 3D-WLP based MEMS 57 3.1.2 Integration concepts 58 3.2 Objective and requirements for the proposed 3D-WLP of MEMS 60 3.2.1 Boundary conditions 60 3.2.2 Technology concepts 63 3.3 Selected approaches for TSV implementation in MEMS 64 3.3.1 Via Last Technology 64 3.3.2 Via Middle technology 69 4 Development of process modules 75 4.1 Characterisation 75 4.2 TSV related etch processes 77 4.2.1 Equipment 77 4.2.2 Deep silicon etching 78 4.2.3 Etching of the buried dielectric layer 84 4.2.4 Patterning of TSV isolation liner – spacer etching 90 4.2.5 Summary 92 4.3 TSV isolation 93 4.3.1 Principle considerations 93 4.3.2 Experiment 95 4.3.3 Results 97 4.3.4 Summary 102 4.4 Metallisation of TSV and RDL 103 4.4.1 Plating base and experimental setup 103 4.4.2 Investigations related to the ECD process 106 4.4.3 Pattern plating 117 4.4.4 Summary 123 4.5 Wafer Level Bonding 124 4.5.1 Silicon direct bonding 124 4.5.2 Thermo-compression bonding by using ECD copper 128 4.5.3 Summary 134 4.6 Wafer thinning and TSV back side reveal 134 4.6.1 Thinning processes 134 4.6.2 TSV reveal processes 136 4.6.3 Summary 145 4.7 Under bump metallisation and solder bumps 146 5 Demonstrator design, fabrication and characterisation 149 5.1 Single wafer demonstrator for electrical test 149 5.1.1 Demonstrator design and test structure layout 149 5.1.2 Demonstrator fabrication 150 5.1.3 Electrical measurement 151 5.1.4 Summary 153 5.2 Via Last based TSV fabrication in the MEMS device wafer 153 5.2.1 Layout of the MEMS device with TSVs 153 5.2.2 Fabrication of TSVs and wafer thinning 154 5.2.3 Characterisation of the fabricated device 155 5.2.4 Summary 156 5.3 Via Last based cap-TSV for very thin MEMS devices 157 5.3.1 Design 157 5.3.2 Fabrication 158 5.3.3 Characterisation 161 5.3.4 Summary 162 5.4 Via Middle approach based on thinning after bonding 163 5.4.1 Design 163 5.4.2 Results and characterisation 164 5.4.3 Summary 166 6 Conclusion and outlook 167 Appendix A: Typical requirements on a MEMS package and its functions 171 Appendix B: Classification of packaging and system integration techniques 173 B.1 Packaging of electronic devices in general 173 B.2 Single Chip Packages 174 B.3 System integration 175 B.4 3D integration based on TSVs 180 Bibliography 183 List of figures 193 List of tables 199 Versicherung 201 Theses 203 Curriculum vitae 205 Own publications 207
Im Bereich mobiler Elektronik, wie z.B. bei Smartphones, Smartcards oder in Kleidung integrierten Geräten ist ein Trend zu erkennen hinsichtlich steigender Funktionalität und Miniaturisierung. Bei dieser Entwicklung spielen Mikroelektromechanische Systeme (MEMS) eine entscheidende Rolle zur Realisierung neuer Funktionen, wie z.B. der Bewegungsdetektion. Die Anforderungen derartiger Bauteile zusammen mit dem begrenzten zur Verfügung stehenden Platz erfordern neuartige Technologien für die Aufbau- und Verbindungstechnick (engl. Packaging) der Bauteile. Das 3D-Wafer Level Packaging (3D-WLP) ermöglicht eine Lösung für eine miniaturisierte MEMS-Bauform unter Nutzung von Techniken wie dem Waferlevelbonden (WLB) und den Siliziumdurchkontaktierungen (TSV von engl. Through Silicon Via). Diese Technologie erhöht die effektive aktive Fläche des MEMS Bauteils durch die Reduzierung von Toträumen, welche für andere Ansätze wie der Drahtbond-Montage üblich sind. In der vorliegenden Arbeit wurden verschiedene Technologiekonzepte für den Aufbau von 3D-WLP für MEMS erarbeitet. Dabei lag der Fokus auf einer Kupfer-basierten Technologie sowie auf zwei prinzipiellen Varianten für die TSV-Implementierung. Dies umfasst den Via Middle Ansatz, welcher auf der TSV Herstellung auf einem separaten Kappenwafer beruht, sowie den Via Last Ansatz mit einer TSV Herstellung entweder im MEMS-Wafer oder im Kappenwafer. Für beide Varianten mit individuellen Herausforderungen wurden entsprechende Prozessmodule entwickelt. Beim Via Middle Ansatz ist die Wafer-bezogene Ätzratenhomogenität des Siliziumtiefenätzen entscheidend für das spätere Freilegen der TSVs von der Rückseite. Hier hat sich eine Reduzierung der TSV-Tiefe auf bis zu 80 μm vorteilhaft erwiesen insofern, das Kupfer-Thermokompressionsbonden (Cu-TKB) vor dem Abdünnen erfolgt. Zur Metallisierung der TSVs wurde ein Cu Galvanikprozess erarbeitet, welcher es ermöglicht gleichzeitig eine Umverdrahtungsebene sowie die Bondstrukturen für das Cu-TKB zu erzeugen. Beim Via Last Ansatz ist die TSV Isolation eine Herausforderung. Es wurden CVD (Chemische Dampfphasenabscheidung) Prozesse untersucht, wobei eine Kombination aus PE-TEOS und SA-TEOS sowie eine Parylene Beschichtung erfolgversprechende Ergebnisse liefern. Des Weiteren wurde eine Methode zur Erzeugung bondfähiger Oberflächen für das Siliziumdirektbonden erarbeitet, welche eine Nass-Vorbehandlung des MEMS umgeht. Ein realer MEMS-Beschleunigungssensor sowie Testaufbauten dienen zur Demonstration der Gesamtintegrationstechnologie sowie zur Charakterisierung elektrischer Parameter.:Bibliographische Beschreibung 3 Vorwort 13 List of symbols and abbreviations 15 1 Introduction 23 2 Fundamentals on MEMS and TSV based 3D integration 25 2.1 Micro Electro-Mechanical systems 25 2.1.1 Basic Definition 25 2.1.2 Silicon technologies for MEMS 26 2.1.3 MEMS packaging 29 2.2 3D integration based on TSVs 33 2.2.1 Overview 33 2.2.2 Basic processes for TSVs 34 2.2.3 Stacking and Bonding 47 2.2.4 Wafer thinning 48 2.3 TSV based MEMS packaging 50 2.3.1 MEMS-TSVs 50 2.3.2 3D-WLP for MEMS 52 3 Technology development for a 3D-WLP based MEMS 57 3.1 Target integration approach for 3D-WLP based MEMS 57 3.1.1 MEMS modules using 3D-WLP based MEMS 57 3.1.2 Integration concepts 58 3.2 Objective and requirements for the proposed 3D-WLP of MEMS 60 3.2.1 Boundary conditions 60 3.2.2 Technology concepts 63 3.3 Selected approaches for TSV implementation in MEMS 64 3.3.1 Via Last Technology 64 3.3.2 Via Middle technology 69 4 Development of process modules 75 4.1 Characterisation 75 4.2 TSV related etch processes 77 4.2.1 Equipment 77 4.2.2 Deep silicon etching 78 4.2.3 Etching of the buried dielectric layer 84 4.2.4 Patterning of TSV isolation liner – spacer etching 90 4.2.5 Summary 92 4.3 TSV isolation 93 4.3.1 Principle considerations 93 4.3.2 Experiment 95 4.3.3 Results 97 4.3.4 Summary 102 4.4 Metallisation of TSV and RDL 103 4.4.1 Plating base and experimental setup 103 4.4.2 Investigations related to the ECD process 106 4.4.3 Pattern plating 117 4.4.4 Summary 123 4.5 Wafer Level Bonding 124 4.5.1 Silicon direct bonding 124 4.5.2 Thermo-compression bonding by using ECD copper 128 4.5.3 Summary 134 4.6 Wafer thinning and TSV back side reveal 134 4.6.1 Thinning processes 134 4.6.2 TSV reveal processes 136 4.6.3 Summary 145 4.7 Under bump metallisation and solder bumps 146 5 Demonstrator design, fabrication and characterisation 149 5.1 Single wafer demonstrator for electrical test 149 5.1.1 Demonstrator design and test structure layout 149 5.1.2 Demonstrator fabrication 150 5.1.3 Electrical measurement 151 5.1.4 Summary 153 5.2 Via Last based TSV fabrication in the MEMS device wafer 153 5.2.1 Layout of the MEMS device with TSVs 153 5.2.2 Fabrication of TSVs and wafer thinning 154 5.2.3 Characterisation of the fabricated device 155 5.2.4 Summary 156 5.3 Via Last based cap-TSV for very thin MEMS devices 157 5.3.1 Design 157 5.3.2 Fabrication 158 5.3.3 Characterisation 161 5.3.4 Summary 162 5.4 Via Middle approach based on thinning after bonding 163 5.4.1 Design 163 5.4.2 Results and characterisation 164 5.4.3 Summary 166 6 Conclusion and outlook 167 Appendix A: Typical requirements on a MEMS package and its functions 171 Appendix B: Classification of packaging and system integration techniques 173 B.1 Packaging of electronic devices in general 173 B.2 Single Chip Packages 174 B.3 System integration 175 B.4 3D integration based on TSVs 180 Bibliography 183 List of figures 193 List of tables 199 Versicherung 201 Theses 203 Curriculum vitae 205 Own publications 207

The main objective of the project was to establish a fracture-mechanics energy-based approach for the design of structural adhesive joints under cyclic loading. This required understanding how an adhesive system behaved near its fatigue threshold, and how the key factors affected this behavior in a fresh undegraded joint. The investigated factors were mode ratio (phase angle), substrate material, surface treatment and surface roughness (both affecting the bond strength), bondline thickness and load ratio. It was first required to understand how the adhesive system behaved under quasi-static loading by examining a fracture mechanics-based design approach for adhesive systems with different substrate materials and geometries. Experiments were initially performed to characterize the strength of aluminum and steel adhesive systems based on the fracture envelope, critical strain energy release rate as a function of the mode ratio. Ultimate failure loads of aluminum and steel adhesive joints, having different overlap end conditions and different geometries were then experimentally measured. These values were compared with the failure loads extracted from the fracture envelope. Considering the toughening behavior of the adhesive in the fracture mechanics analyses, a very good agreement (average of 6%) was achieved between the predictions and experiments for all types of overlap end conditions and geometries. Different fatigue threshold testing approaches, which are commonly used in the literature or suggested by the ASTM standard, were evaluated for the cracked and intact fillet joints. Based on the experimental and analytical studies, the most appropriate technique for fatigue testing and characterization of adhesive systems was suggested. Comparing the mixed-mode near-threshold behavior of different adhesive systems with the fracture behavior and fatigue mode-I and mixed-mode high crack growth rates showed the high sensitivity of the mixed-mode near-threshold fatigue to the subtle changes in the interfacial bond strength. In order to make a baseline for the design of adhesive joints under cyclic loading, similar to the previous fracture tests and following the energy-based approach, fatigue behavior was characterized as a function of the loading mode ratio for aluminum and steel adhesive joints. The effect of substrate material, surface treatment, bondline thickness, surface roughness and fatigue testing load ratio on the near-threshold fatigue behavior of adhesives joints was evaluated experimentally. The experimental observations were then explained using finite element modeling. To generalize the conclusions, the majority of experiments and studies covered a broad range of crack growth rates, as low as fatigue threshold and as high as 10-2 mm/cycle. Having understood the significant testing and design parameters, an adhesive system can be designed based on a safe cyclic load that produces an insignificant (for automotive industry) or reasonably low but known crack growth rate (for aerospace industry).

碩士
國立彰化師範大學
機電工程學系
92
The study aims at the anodic bonding of P-type silicon and Pyrex 7740 glass with intermedium metal film by RF magnetron sputtering. The experimental parameters included the intermedium metal materials, film thickness, bonding temperature and bonding voltage, respectively. The Taguchi method was used to find the optimum bonding condition. The target functions included the increased maximum bonding current, charge bonding quantity, bonding area ratio and bonding strength, respectively. The maximum bonding current is measured using an amperemeter. The bonding area observation is estimated using an optical microscope. The measurement of bonding strength is according to the microcircuits test standard of department of defense in USA (Mil-STD-883E, Method 2027.2). The element dispersal inside the glass is analyzed using an energy dispersive spectrometer. Based on the Taguchi analysis of the experimental results showed that the bonding voltage is a dominant factor to effect on the maximum bonding current; the bonding voltage is a dominant factor to effect on the charge bonding quantity; the film thickness is a dominant factor to effect on the bonding area ratio; the intermedium metal materials is a dominant factor to effect on the bonding strength. The optimum condition occurs at intermedium film of aluminum with 0.1μm film thickness, bonding temperature of 350℃, and bonding voltage of 500V, respectively. The optimum bonding condition was verified experimentally resulting in the bonding area ratio error of 3.6% and the bonding strength error of 5.7%.

Contents Metallic solids 343 Close packing 343 Example 38.1: Calculating a packing fraction 344 Electronic structure of metals 345 Brief illustration 38.1: Energy levels in a band 346 Ionic solids 347 Structure 347 Brief illustration 38.2: The radius ratio 348...

This chapter describes what happens when different elements combine. The sizes of the orbitals involved and the number of valence electrons is important when considering the bonding in the elements, but when different elements combine there is the added complication that their orbital energies will be different. This leads to the possibilities of polar bonds and compounds in which electrons have essentially been transferred from one element to another, i.e. ionic compounds. Depending on the energy separation of the orbitals involved, the bonding can vary on a spectrum from purely covalent to ionic. Trying to predict the structure that a particular compound will adopt is very difficult. However, there are a few general concepts which can be applied to at least give some indication as to the likely structure. The concept of the radius ratio can help one to understand the different structures adopted by ionic solids.

This chapter looks closely at covalent, metallic, and ionic bonding in solid state structures, which is important as the properties of solid state materials depend on their structures and bonding. Some of the characteristic/properties of molecular solids, covalent network structures, metals, and ionic solids are summarized. The chapter describes the differences between cubic close packing (ccp) and hexagonal close packing (hcp). It demonstrates how to predict the limiting radius ratio for different geometries and how to use the radius ratio rule to predict the structures of ionic compounds. It also outlines how to calculate packing efficiencies and densities, lattice enthalpies using Born–Haber cycle compounds, and lattice energies using the Born–Landé equation and the Kapustinskii equation.

Aluminum metal matrix composites are materials frequently used in the automotive and aerospace industries due to their high strength-to-weight ratio, formability, corrosion resistance, and long-term durability. However, despite the unique properties of these materials, the lack of a reliable joining method has restricted their full potential in engineering applications. This article explores the effect of bonding time on transient liquid phase diffusion bonding of Al6061 containing 15 vol.% alumina particles using a 5 μm electrodeposited Ni-coating containing nano-sized alumina particles as the interlayer. Joint formation was attributed to the solid-state diffusion of Ni into the Al6061 alloy followed by eutectic formation and isothermal solidification at the joint interface. Examination of the joint region using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction showed the formation of eutectic phases such as Al3Ni, Al9FeNi, and Ni3Si within the joint zone. The results indicate that the addition of nano-size reinforcements into the interlayer can be used to improve joint strength. The joint strength recorded was 136 MPa at a bonding time of 10 min with a marginal increase in the shear strength when the bonding time is increased to 30 min.

This paper presents the analysis of the Pineapple Leaf Fiber (PALF) reinforced composite used as a material for car bumpers. Impact analysis is performed on the modeled front car bumper at different fiber content, i.e., at the difference in the value of the fiber volume fraction, and the results are discussed. The objective is to model a car's rear bumper with considered dimensions, and analyze it by simulating in the circumstances of a crash, i.e., the impact is simulated against a rigid body at speed as per the standards of the vehicle. The natural fiber reinforced composite, which has good specific weight compared to synthetic fiber, results in a reduction in the weight of the whole body, resulting in less weight-to-volume ratio, when compared to the use of synthetic fibers and, therefore, can be considered as a material for car front bumper. There may certainly be a difference in performance, but depending on the required applications, the fiber-matrix bonding, and the aspect ratio can be varied. For PALF, the compensation for the low value of modulus can be done by having a very high aspect ratio, as the composite modulus is influenced by both young’s modulus and aspect ratio. In PALF reinforced Composites, the variation of fiber content affects the performance of the composites with less increase in overall weight compared to that of synthetic fibers.

The manufacturing of cost-efficient construction materials is at the center of attention these days. The development of engineeringly design products has occurred mostly over the past few decades. However, the term of mineral bonded wood composite is relatively new, covers many of the products, and is used to describe a material that is produced by bonding woody material with mineral-based substrates. At present, millions of tons of bio-based composite materials are now manufactured annually from many wood species. Woods are sustainable and engineeringly have enough performance properties in composite matrix systems for many end-use areas. Thus, their utilization processes and intended uses vary accordingly. But at manufacturing, many variables affect binder hydration in composite structure and the networking/bonding between wood and binder. The mineral bonded wood products are high in density and the appropriate strength in the construction industry, an important advantage to engineering applications appears to lie in their ability to absorb and dissipate mechanical energy. Despite their higher weight-to-strength ratio, especially cement and gypsum bonded wood composites have become popular, for use in many internal and external applications to meet increasingly stringent building design regulations for insulation, and failure in service due to deterioration.

Polymeric nanocomposites are generally lighter and stronger that hold key features for many industrial applications, such as aerospace, automotive, defense, packing, electrical and electronics, biomaterials, sensors, energy, and consumer products. Their exceptional mechanical, electrical, chemical, and thermal properties help bring these materials as one of the prime focus areas in the world. Extensive research studies involving thermoplastics with nanofillers (TiO2, graphene, carbon black, and carbon nanotubes) have been conducted to produce various nanocomposites. The prime objective of this study is to develop polymeric nanocomposites by incorporating nanoparticles of graphene into polyacrylonitrile (PAN) thermoplastic where fiber reinforcement bonding is used to enhance the mechanical properties leading to very high strength-to-weight ratio polymeric nanocomposites. A mixing ratio of 20:80 for PAN and dimethylformamide (DMF) solvent was used to dissolve the PAN power using magnetic stirring. Graphene nanoparticles were then added to the solution at 0-4 wt.% ratio after which the nanocomposite coupons were prepared by casting the PANbased resin in aluminum grooves where carbon fibers and SiC fibers were placed as reinforcement materials to make them robust. After curing at room temperature, the coupons were oxidized at 200°C for 2 hours in air and then carbonized at 650°C for additional 2 hours in Ar gas. The subsequent testing and characterization studies, such as tensile, Fourier-transform infrared spectroscopy (FTIR), and water contact angle have been conducted on the prepared nanocomposites. The obtained test results indicated that the mechanical and thermal properties have been significantly enhanced after the addition of a small percentage of nanoparticles into the PAN solution. This enhancement can be attributed to the fact that the surface-to-volume ratio is high for nanoparticles, thereby making them more resilient compared to traditional composites.

This chapter surveys the chemical factors that influence the chemical shift and the magnitude of coupling constants. Shielding is influenced by the fields generated by circulation of ground state electrons around the nucleus (diamagnetic term) and by electrons mixed in from excited states (the paramagnetic term). The diamagnetic contribution is usually small and dominates for light elements, resulting in (usually) small chemical shift ranges for these elements. The paramagnetic term dominates for heavier elements and is often large, resulting in large chemical shift ranges for these elements. The chemical shift is influenced by many, often competing factors, including oxidation state, electronegativity, coordination number, and bonding to other atoms. Meanwhile, scalar coupling constants are influenced by similar factors and by geometric factors, particularly interbond and dihedral angles. If all other factors are kept constant, scalar couplings between different isotopes of the same elements scale with gyromagnetic ratio.

Abstract The frictional properties of a hybrid lubricant film composited from perfluoropolyether (PFPE) lubricant (Moresco DDOH) with single end group and PFPE film deposited from HT170 (Solvay) via photoelectron-assisted chemical vapor deposition (PACVD) were evaluated using a pin-on-disk tester and compared with that of a Z-tetraol dip-coated film. The frictional coefficient of only the HT170 film deposited via PACVD was considerably high; however, the hybrid lubricant film without the mobile fraction showed a friction coefficient equivalent to that of the Z-tetraol film with a mobile fraction of 40%.

Hybrid microfluidic and nanofluidic devices have a variety of applications including water desalination, molecular gates and DNA sieving among several other lab-on-chip uses. Most microfluidic and nanofluidic devices currently are fabricated in glass, silicon, polydimethylsiloxane (PDMS), or with a combination of these materials. In order to impart functionality, metals, polymers or auxiliary components are often integrated with these devices. Ultra-low aspect ratio channels have several advantages including critical dimensions on the nanoscale but increased throughput compared to higher aspect ratio channels with the same critical dimension, which is important for applications where a higher volumetric flow rate is desired. Additionally, theoretical analysis is significantly easier as ultra-low aspect ratio channels can be modeled as 1-D systems. The fabrication methods for achieving low aspect ratios (< 0.005) usually require extensive facilities with several innovative fabrication and bonding schemes being previously reported. In this paper, we report on fabrication and bonding of ultra-low aspect ratio microfluidic and nanofluidic devices with aspect ratios at 0.0005 in glass/PDMS devices in contrast to the previous best reported result of 0.005 achieved in a silica device using stamp and stick PDMS bonding. The simplicity of our approach presents a new pathway to achieving the lowest aspect ratio nanochannels ever reported for channels fabricated using an interfacial layer for bonding. Centimeter long nanochannels on a borosilicate substrate were fabricated by standard UV photolithography followed by wet etching. Surface roughness of the fabricated channels is on the same order as the roughness of the initial substrate (2–3 nm) and therefore can enable fabrication of channels with critical dimensions approaching 15 nm or less. Devices were then bonded using a second borosilicate substrate with a thin PDMS adhesion layer (∼ 2 μm). The PDMS adhesion layer allows rapid, facile, and alignment-free bonding compared to traditional fusion or anodic bonds. Successful verification of device operation and functionality was determined by verifying flow in operational devices and with scanning electron microscopy to confirm bonding for the formation of nanochannels.

Abstract Thermally sprayed coatings exhibit a lamellar structure with a bonding ratio less than 32% when a coating is deposited at ambient temperature. The lamellar bonding is one of the most important factors controlling the mechanical, thermal and electrical properties of the coatings. However, it is not clear why only limited lamellar bonding exists in a thermal spray coating even though many studies have been focused on the formation of bonding. In our previous study, it was found that there exists a critical deposition temperature for depositing ceramic splats to form the bonding with the underlying identical substrate, i.e., critical bonding temperature. Moreover, the critical bonding temperature is related to the interface temperature prior splat solidification which is determined by the glass transition temperature of splat material. In the present study, the critical bonding temperature and its relationship with interface temperature are used to understand the limited lamellar bonding ratio in a coating. A numerical simulation model involving heat transfer among depositing splat was proposed to establish the sufficient condition for liquid splat to form the bonding with the underlaying splats. The non-uniform splat thickness model was established to calculate theoretically the interface bonding formation. The calculation based on the model yielded a bonding ratio of 38.5% which agrees reasonably with the observed maximum interface bonding ratio.

Abstract Thermally sprayed coatings are formed through the successive impact of molten droplets and/or semi-molten particles followed by flattening, rapid cooling, and solidification. Individual droplets flatten to form splats of several micrometers in thickness upon impact and result in the formation of a coating that has a lamellar structure with limited interface bonding. The inclusion of semi-molten particles in the coating modifies its microstructure. The bonding between particles dominates coating properties and performance. This review paper examines the bonding formation at the interface between thin lamellae in the coating. The effect of spray parameters on the bonding ratio is presented to reveal the main droplet parameters controlling bonding formation. It is shown that spray particle temperature dominates the bonding formation more than particle velocity. Significant increases in ceramic particle temperature are not possible due to the inherent characteristics of thermal spray processing; therefore, the bonding ratio is limited to a maximum of about 32%. On the other hand, it was found that through controlling the surface temperature of coating prior to molten droplet impact, the bonding at the lamellar interface can be significantly increased. Consequently, with the proper selection of deposition conditions and control of surface temperature, the bonding ratio of ceramic deposits can be altered from a maximum of 32% for a conventional deposit to the maximum of 100%. Such wide adjustability of lamellar bonding extends the applicability of plasma spray coatings to applications requiring different microstructures and properties. Moreover, this bonding control makes it possible to fabricate porous surfaces and structures through the deposit of surface-molten particles, to deposit high temperature abradable ceramic coatings, and to form super-hydrophobic surfaces. Furthermore, the ability to deposit coatings with complete interface bonding allows crystalline structure control of individual splats through epitaxial grain growth.

Abstract The corrosion resistance of thermal barrier coatings against CMAS deposit at high temperature is significantly affected by the microstructure of the coatings. Enhancing the bonding ratio between splats can reduce the inter-connected pores and then obstructs the penetration of the molten CMAS into the coatings. In this study, atmospheric plasma sprayed ZrO2 contains 8 wt. % Y2O3 (8YSZ) coating with improved lamellar bonding ratios was deposited with full-molten droplets at an enhanced deposition temperature. The microstructure of the dense 8YSZ coating and conventional 8YSZ coating before and after thermal exposure with CMAS were characterized. It was clearly revealed that by adjusting the microstructure and designing a ceramic layer with high bonding ratio, the corrosion resistance of the thermal barrier coating could be enhanced. Moreover, by designing double-ceramic-layer (DCL) TBCs composed of a porous ceramic layer and well-bonded ceramic layer, the TBCs with high CMAS corrosion resistance and low thermal conductivity can be achieved.

Abstract In this study, yttria-stabilized zirconia (YSZ) coatings were plasma sprayed on heated substrates at temperatures ranging from room temperature to 1100 °C. Lamellar mean bonding ratio was estimated from the ionic conductivity of the coatings and mechanical properties were measured by indentation testing. The bonding ratio, elastic modulus, and fracture toughness of the YSZ coatings were found to increase with substrate surface temperature. The results show that the mechanical properties of plasma sprayed ceramic coatings are determined by interlamellar bonding and that significant improvements can be achieved by controlling coating surface temperature.

The morphology and bonding characteristics of nanocrystalline diamond films prepared with different Ar:H ratios have been studied and are correlated to tribological performance. A coating made with high Ar:H ratio displayed low friction of 0.05 and very minimal wear, while the low Ar:H film showed high friction (&gt; 0.2), rapid wear, and complete failure after 50 cycles. As both films had the same rms roughness, their different tribology appears to stem from a change in morphology.