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1
Li, Yi Nan, Z. L. Peng, and J. C. Yan. "GTA Welding of Copper Thick Plates by Using ERCuTi Welding Materials." Materials Science Forum 697-698 (September 2011): 409–13. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.409.
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The new welding material – ERCuTi alloys filler metals were developed specially for gas tungsten arc welding (GTAW) of copper. The hot cracking in welding copper is inhibited completely as the addition of de-oxidant element Ti in copper welding material. The degree of addition of Ti (2-4wt%) is critical when the susceptibility of cracking is to be suppressed. If the level is allowed to exceed 4wt%, more low-melting point eutectics (β-TiCu4and TiCu2) will be formed in the welds, and cracking susceptibility will be increased again. Results of mechanical properties tests show that although adding Ti increases the hardness and strength of the weld compared to the base metal, the impact ductility and the plastic properties are not decreased significantly.
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Hosseini, Vahid A., Kristina Lindgren, Mattias Thuvander, Daniel Gonzalez, James Oliver, and Leif Karlsson. "Nanoscale phase separations in as-fabricated thick super duplex stainless steels." Journal of Materials Science 56, no. 21 (April 19, 2021): 12475–85. http://dx.doi.org/10.1007/s10853-021-06056-0.
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AbstractNanoscale phase separations, and effects of these, were studied for thick super duplex stainless steel products by atom probe tomography and mechanical testing. Although nanoscale phase separations typically occur during long-time service at intermediate temperatures (300–500° C, our results show that slowly cooled products start to develop Fe and Cr separation and/or precipitation of Cu-rich particles already during fabrication. Copper significantly slowed down the kinetics at the expense of Cu-rich particle precipitation, where the high-copper material subjected to hot isostatic pressing (HIP), with Δt500–400 of 160 s and the low-copper hot-rolled plate with Δt500–400 of 2 s had the same level of Fe and Cr separation. The phase separations resulted in lower toughness and higher hardness of the HIP material than for hot-rolled plate. Therefore, both local cooling rate dependent and alloy composition governed variations of phase separations can be expected in as-fabricated condition.
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Loquet, Yannick, Cedric Perrot, Pierre Bouillon, and Blaise Iteprat. "Chemical-Mechanical Planarization Compatible for Both Copper/Low k Level in a 90 nm Technology and Thick Copper Level in an RF Technology." ECS Transactions 3, no. 41 (December 21, 2019): 1–8. http://dx.doi.org/10.1149/1.2819476.
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Richard, Claire Therese, M. M. Frank, Pascal Besson, E. Serret, N. Hotellier, Alessio Beverina, L. Dumas, Lucile Broussous, F. Kovacs, and Thierry Billon. "Barrier and Copper Seedlayer Wet Etching." Solid State Phenomena 103-104 (April 2005): 361–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.103-104.361.
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This paper summarizes the process development of TiN barrier etching in presence of copper, for a thick copper level in BICMOS technology. In an industrial context, we have chosen to use a SC1 chemistry in a spin etch single wafer tool. The SC1 composition and therefore the pH level allows - the barrier to be etched with no metallic residues, ( if not clear this can be a source for shorts) - control of the selectivity between copper and TiN - control of lateral etching under copper lines, the possible source of open chains by W attack during TiN etch. The electrical results show a robust process according to current specifications, in terms of leakage and via resistance with a fresh chemistry approach. In fact, the recirculation of SC1 is not possible due to substantial concentration changes during processing, high evaporation rate of Ammonia and high decomposition rate of Peroxide in the presence of copper on surface wafer.
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Lee, Suhyun, Chien Wern, and Sung Yi. "Novel Fabrication of Silver-Coated Copper Nanowires with Organic Compound Solution." Materials 15, no. 3 (February 1, 2022): 1135. http://dx.doi.org/10.3390/ma15031135.
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Copper nanowires and Cu-Ag nanowires have various potential applications, such as transparent conductive film, flexible electronics, and conductive filler. In this study, we developed a new green fabrication method for silver-coated copper nanowires using methylsulfonylmethane (DMSO2), which is an environmentally friendly chemical at the food-grade level, to replace toxic chemicals, including ammonia, in the silver coating process. Copper nanowires were synthesized under various reaction temperatures and concentrations of hydrazine (N2H4), ethylenediamine (EDA), sodium hydroxide (NaOH), and copper precursor. The reaction temperature higher than 70 °C caused the oxidation of copper products and evaporation of the sample solution. The optimal conditions to synthesize copper nanowires more than 18 µm in length and 25–45 nm in diameter were determined: 9 M of NaOH, 50 µL of EDA, 17 mM of CuCl2, 5.7 mM of N2H4, and 70 °C reaction temperature. Cu-Ag nanowires, which have about a 12 nm thick silver shell, were successfully fabricated at room temperature under 1 mM of silver nitrate (AgNO3) and 1 wt % of DMSO2. Synthesis conditions for copper and silver-coated copper nanowires have been optimized.
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Aoh, Jong Ning, Chih Wei Huang, and Wei Ju Cheng. "Fabrication of Al6061-AMC by Adding Copper-Coated SiC Reinforcement by Friction Stir Processing (FSP)." Materials Science Forum 783-786 (May 2014): 1721–28. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1721.
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Friction stir processing (FSP) has successfully evolved as a technique in fabricating surface composite. An alternative technique on fabrication of a SiC-reinforced Al6061 aluminum matrix composite (AMC) by stirring copper-coated SiC particles into matrix to form a reinforced zone was developed. Copper film was deposited onto the SiC particles by electroless plating and by photodeposition processes. The copper coating serves as an adhesion and diffusion layer to enhance the cohesion between the particles and the matrix. It is to expect that the strength of the AMC could be improved. The uniformity of particle distribution in the stir zone (SZ) was improved by adjusting the location of particle insert and by a double-pass stir. T5 post weld heat treatment (PWHT) was conducted to retrieve the hardness and the strength of the SZ to the strength level of the matrix. While the submicron-thick Cu-coating was partially separated from SiC particles after FSP, photodeposition Cu-coating less than 100 nm thick exhibited a better adhesion to the SiC particles. The EPMA analysis across the interface shows evidence of interdiffusion between copper and aluminum which implies an enhanced cohesion between the particles and matrix. After PWHT, while the SZ containing photodeposition Cu-coated SiC exhibited the highest hardness among different SZs, the SZ containing electroless Cu-coated SiC exhibited the highest strength. The possible mechanisms for the improvement of the hardness and strength were discussed. In summary, the purpose of fabricating a locally particulate-reinforced Al6061 AMC by stirring Cu-coated SiC particles into Al6061 matrix was achieved. Keywords:Friction stir processing (FSP), particulate reinforced AMC, electroless plating, photodeposition, copper-coated SiC particles
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Gorbatyuk, S. M., A. A. Gerasimova, and N. N. Belkina. "Applying Thermal Coatings to Narrow Walls of the Continuous-Casting Molds." Materials Science Forum 870 (September 2016): 564–67. http://dx.doi.org/10.4028/www.scientific.net/msf.870.564.
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Studies on enhancing the service life of continuous casting moulds at their narrow walls of copper M1 before the last repair by means of a heat spraying wear-resistant layer of the chrome-nickel coating have been carried out. Preliminary, the coating`s structure, phase composition, skin hardness and microhardness of chromium-nickel coating were studied. It is established that to obtain the required cleanliness level of the wall surface by making use of their mechanical operation, it is necessary to conduct thickness of the chromium-nickel coating operations. 0.5 – 0.6 mm chrome-nickel thermal coating was applied to the surface of the wall of a thick-walled narrow pair crystallizer. The results indicate the high-quality coating acceptable for application to the working surface of narrow walls of thick-walled moulds.
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Mantatova, N. V., Chuluunbatyn Oyuuntsetseg, and S. Ye Sanzhiyeva. "TRACE ELEMENT CONTENT IN BLOOD OF CATTLE WITH ALIMENTARY ANEMIA AND HYPOCUPROSIS, AND IN SOIL SAMPLES OF THE TÖV AIMAG OF MONGOLIAAND THE KYAKHTINSKY DISTRICT OF THE REPUBLIC OF BURYATIA." Vestnik Altajskogo gosudarstvennogo agrarnogo universiteta, no. 8 (2021): 61–66. http://dx.doi.org/10.53083/1996-4277-2021-202-08-61-66.
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This paper discusses the results of laboratory tests of biochemical indices of blood serum (copper, iron, protein, albumin, urea, glucose, and alkaline reserve) of cattle of Mongolian and Kalmyk breeds with alimentary anemia and hypocuprosis; the paper also discusses the findings of the comparative study of trace element composition (copper, zinc, cobalt, nickel, molybdenum, strontium, iron, and man-ganese) of the soils of the Töv Aimag of Mongolia and the Kyakhtinsky District of the Republic of Buryatia. The disor-ders of mineral metabolism in animals of Mongolian and Kalmyk breeds with clinical signs of alimentary anemia and hypocuprosis was accompanied by the signs of hypocu-premia and hyposideremia, i.e., insufficient content of cop-per and iron in the blood. When studying the causes of trace element deficiency in cattle, the natural geographic features of the deficiency concern areas were considered. It has been found that the endemic foci are common in light-chestnut soils and thin chestnut soils around lakes and stock watering sites in Mongolia and the Kyakhtinsky District of the Republic of Buryatia. As compared to medi-um-thick chestnut soil, light chestnut soil of the Töv Aimag of Mongolia is poor in copper by 21.9%; cobalt -by 32.4%; strontium -by 11.7%; iron –by 19.7%; manganese -by 9.9%; richer in zinc by 32.9%; molybdenum -by 7.7%. The content level differences in the medium-thick chestnut soil as compared to light chestnut soil of the Kyakhtinsky Dis-trict of the Republic of Buryatia are as following: copper -more by 25.0%; cobalt -by 40.3%; nickel -by 11.8%; mo-lybdenum -by 38.7%; strontium -by 16.3%; iron -by 53.8%.
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Prem Kumar, T., V. Muthupriya, A. Antony Christian Rajaa, R. Sasirekab, and R. Sumanc. "World Best Level Efficiency from An Engineered Novel SLG/Mo/p-Cu2ZnSn(Al)Se4/n-CdS/i-ZnO/Al:ZnO/Al Compound Semiconductor Hetero-Junction Thin Film Solar Cells." Shanlax International Journal of Arts, Science and Humanities 9, S1-May (May 14, 2022): 41–46. http://dx.doi.org/10.34293/sijash.v9is1-may.5942.
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Molybdenum (Mo) metal seed layer deposited on soda lime glass (SLG) substrate and then Mo thick metal layer deposited on Mo seed layer. Then the Copper zinc tin aluminum selenide p-Cu2ZnSn(Al)Se4 (CZTAS) thin film was fabricated on molybdenum (Mo) thin film layer. For making p-n junction a n-CdS thin films fabricated on p-CZTAS layer using chemical bath deposition method. The surface morphology of total device structure was investigated by Scanning electron microscopy (SEM). The observed world best level efficiency and its note worthy results are presented and discussed in this research work.
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Schmidt, Ralf, Jens Palm, and Jan M. Knaup. "The Pivotal Role of Uniformity of Electrolytic Deposition Processes to Improve the Reliability of Advanced Packaging." International Symposium on Microelectronics 2021, no. 1 (October 1, 2021): 000142–48. http://dx.doi.org/10.4071/1085-8024-2021.1.000142.
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Abstract Heterogeneous integration is considered as the key technology to create large, complex System in Package (SiP) assemblies of separately manufactured, smaller components. Proper control of the uniformity of each process step constitutes one of the main challenges during integration of the different components into a higher-level assembly. In this context, processes that create thick layers by electrochemical deposition are especially susceptible to variations across the substrate. Such processes include copper pillar and bump as well as tin-silver applications. Insufficient coplanarity of electrolytic copper would result in significant reliability issues or evolution of stress in the package. Upcoming hybrid bump designs with features of different dimensions pose additional challenges to the electrolytic copper and tin-silver processes. Purposeful adjustment of differences between the heights of pillars of different diameters may be required after the copper process step in order to obtain the best uniformity for the complete stack with tin-silver on top. In addition to coplanarity, the electrolytic process should allow modification shape of the individual pillar or bump. In this context, a versatile copper electrodeposition process will be discussed that allows adjustment to a broad variety of uniformity parameters and combinations thereof. In combination with suitable tin-silver deposition processes, this process is expected to significantly improve the reliability of copper pillars and bumps for advanced packaging applications.
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Vityaz, S. N. "Phytoremediation Potential of Flowering Plants in Relation to Copper." Bioscience Biotechnology Research Communications 14, no. 4 (December 25, 2021): 1786–92. http://dx.doi.org/10.21786/bbrc/14.4.60.
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Heavy metals such as cadmium, chromium, nickel, mercury, lead, copper, zinc and others are among the priority environmental pollutants. Determination of their content in its main subsystems is an obligatory component in environmental monitoring and certification of agricultural products. On the other hand, all metals are natural components of soil-forming rocks, and some metals are classified as biogenic microelements, and their absence provokes functional disorders in living organisms. This article describes the results of studying the phytoremediation potential of flowering plants in relation to copper ions under laboratory conditions. The following flowering plants were selected as test crops: tansy phacelia, white mustard, small-flowered marigolds and a mixture of cereal grasses consisting of red fescue, perennial ryegrass and bluegrass in a ratio of 40%, 50%, 10%, respectively. Within the experiment, copper ions in concentrations of 2 and 10 maximum permissible concentration (MPC) were introduced into the soil sampled from the territory of agricultural lands (leached medium-thick heavy loamy chernozem with a high level of humus, mobile phosphorus and exchangeable potassium and a low level of nitrate nitrogen, copper in gross and mobile forms). It was found that all plants selected as test crops are capable of accumulating copper ions from the soil to varying degrees, which makes it possible to use them in phytoremediation of agricultural lands planned for organic farming. The ability to accumulate copper ions increases in the following order: white mustard < small-flowered marigolds < tansy phacelia < mixture of cereal grasses. The maximum effect of soil phytoremediation was revealed in the variant with a mixture of cereal grasses. When they are grown, the content of copper ions in the soil with the introduction of 2 MPC decreases by 38.8%, with the introduction of 10 MPC the concentration decreases by 47.8%.
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Rydosz, Artur, Katarzyna Dyndał, Wojciech Andrysiewicz, Dominik Grochala, and Konstanty Marszałek. "GLAD Magnetron Sputtered Ultra-Thin Copper Oxide Films for Gas-Sensing Application." Coatings 10, no. 4 (April 11, 2020): 378. http://dx.doi.org/10.3390/coatings10040378.
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Copper oxide (CuO) ultra-thin films were obtained using magnetron sputtering technology with glancing angle deposition technique (GLAD) in a reactive mode by sputtering copper target in pure argon. The substrate tilt angle varied from 45 to 85° and 0°, and the sample rotation at a speed of 20 rpm was stabilized by the GLAD manipulator. After deposition, the films were annealed at 400 °C/4 h in air. The CuO ultra-thin film structure, morphology, and optical properties were assessed by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), X-ray reflectivity (XRR), and optical spectroscopy. The thickness of the films was measured post-process using a profilometer. The obtained copper oxide structures were also investigated as gas-sensitive materials after exposure to acetone in the sub-ppm range. After deposition, gas-sensing measurements were performed at 300, 350, and 400 °C and 50% relative humidity (RH) level. We found that the sensitivity of the device is related to the thickness of CuO thin films, whereas the best results are obtained with an 8 nm thick sample.
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Mironovs, Viktors, Alexey Tatarinov, Ervins Blumbergs, and Irina Boiko. "Investigation of Properties of Coated Hollow Mini-Spheres." Key Engineering Materials 799 (April 2019): 26–30. http://dx.doi.org/10.4028/www.scientific.net/kem.799.26.
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Metal hollow mini-spheres (MHMS) present a basis for the creation of new structured materials due to their low weight and energy adsorption capacity. Typically, MHMS are made of steel with a high level porosity in the sphere’s wall 80-110 microns thick. Modification of the outer surface by copper coating of 20-30 microns imposed by vacuum sputtering provides several times higher electrical conductivity, lower porosity of the outer layer and smoother surface, preserving light weight and flotation properties. This modification will provide better possibilities for spheres’ consolidation by means of sintering and electric brazing and creation of new cellular structures.
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Lee, Seong Hee, Seung Zeon Han, and Cha Yong Lim. "Nano-Structured High Purity Copper Processed by Accumulative Roll-Bonding." Key Engineering Materials 317-318 (August 2006): 239–42. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.239.
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Accumulative roll-bonding (ARB) process was applied to an oxygen free copper for improvement of the mechanical properties via ultra grain refinement to nanometer order level. Two copper sheets 1mm thick, 30mm wide and 300mm long are degreased and wire-brushed for sound bonding. The sheets are then stacked to each other, and cold-roll-bonded by 50% reduction rolling. The sheet is then cut to the two pieces of same length and the same procedure was repeated to the sheets. The ARB process up to eight cycles (an equivalent thickness strain of 6.4) is successfully performed at ambient temperature. TEM observation reveals that ultrafine grains, hardly containing the dislocation interior, begin to develop at the third cycle, and after the sixth cycle they cover most of regions of samples. The morphology of ultrafine grains formed is different from that of aluminum alloys. Tensile strength of the ARB-processed copper increases with the equivalent strain up to a strain of ~3.2, in which it reached 390 MPa, ~2.1 times higher than the initial value. However, the strength hardly changed at the strain above ~3.2.
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Vanstreels, K., S. H. Brongersma, Zs Tokei, L. Carbonell, W. De Ceuninck, J. D’Haen, and M. D’Olieslaeger. "Increasing the mean grain size in copper films and features." Journal of Materials Research 23, no. 3 (March 2008): 642–62. http://dx.doi.org/10.1557/jmr.2008.0080.
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A new grain-growth mode is observed in thick sputtered copper films. This new grain-growth mode, also referred to in this work as super secondary grain growth (SSGG) leads to highly concentric grain growth with grain diameters of many tens of micrometers, and drives the system toward a {100} texture. The appearance, growth dynamics, final grain size, and self-annealing time of this new grain-growth mode strongly depends on the applied bias voltage during deposition of these sputtered films, the film thickness, the post-deposition annealing temperature, and the properties of the copper diffusion barrier layers used in this work. Moreover, a clear rivalry between this new growth mode and the regularly observed secondary grain-growth mode in sputtered copper films was found. The microstructure and texture evolution in these films is explained in terms of surface/interface energy and strain-energy density minimizing driving forces, where the latter seems to be an important driving force for the observed new growth mode. By combining these sputtered copper films with electrochemically deposited (ECD) copper films of different thickness, the SSGG growth mode could also be introduced in ECD copper, but this led to a reduced final SSGG grain size for thicker ECD films. The knowledge about the thin-film level is used to also implement this new growth mode in small copper features by slightly modifying the standard deposition process. It is shown that the SSGG growth mode can be introduced in narrow structures, but optimizations are still necessary to further increase the mean grain size in features.
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Tivol, W. F., and J. R. Fryer. "Electron diffraction of copper perfluorophthalocyanine on the HVEM." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 158–59. http://dx.doi.org/10.1017/s0424820100137161.
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The use of high-energy (1200 kV) electrons has been shown to be advantageous in the ab initio structure analysis from electron diffraction of organic compounds. Previous studies showed that ab initio analysis of copper perchlorophthalocyanine could be accomplished at accelerating voltages at or above 1000 kV, but not at 400 kV for crystals which are about 10 nm thick. Copper perbromophthalocyanine could also be analyzed ab initio at 1200 kV, but the presence of severe dynamical scattering precluded such analysis at lower voltages.Copper perfluorophthalocyanine (Cu FPC) was grown epitaxially from the vapor phase onto a clean KC1 crystal face. Electron diffraction patterns were obtained from crystals tilted at 20° and oriented so that the electron beam was parallel to the c-axis.Electron doses were kept to a minimum by the use of a 100 μm condenser aperture and a highly excited first condenser lens. A video system allows scanning the specimen to find a crystal suitable for the correct orientation of the grid by rotating it within its own plane and focusing the objective lens, all at an illumination level below that necessary to distinguish anything by eye on the HVEM's phosphor screen.
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Song, Jian, Songsong Yao, Quan Li, Jiamiao Ni, Zhuoxin Yan, Kunming Yang, Guisen Liu, Yue Liu, and Jian Wang. "Reorientation Mechanisms of Graphene Coated Copper {001} Surfaces." Metals 13, no. 5 (May 8, 2023): 910. http://dx.doi.org/10.3390/met13050910.
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Engineering the surface orientation of face-centered cubic (fcc) metals to the close-packed {111} plane can significantly enhance their oxidation resistance. However, owing to the synergetic effect of surface energy density (γ˙) and strain energy density (ω), such close-packed surface orientation can currently only be achieved by atomic-level thin film epitaxy or monocrystallization of polycrystalline metals. In this study, we characterized the microstructures of pure copper (Cu) foil and two types of graphene-coated Cu (Gr/Cu) foils and observed a 12~14 nm thick reconstructed surface layer with the {111} orientation in the high-temperature deposited Gr/{001} Cu surface. Combining the statistical results with thermodynamic analysis, we proposed a surface melting-solidification mechanism for the reconstruction of the Cu surface from {001} orientation to {111} orientation. This process is dominated by Gr/Cu interfacial energy and is particularly promoted by high-temperature surface melting. We also validated such a mechanism by examining Cu surfaces coated by h-BN (hexagonal boron nitride) and amorphous carbon. Our findings suggest a possible strategy to enhance the surface properties of fcc metals via engineering surface crystallography.
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Skrynnikov, Alexander A., Anastasia I. Fedoseeva, Natalia B. Morozova, Alexey I. Dontsov, Aleksander V. Vvedenskii, and Oleg A. Kozaderov. "Pd–Pb nanoscale films as surface modifiers of Pd,Cu alloy membranes used for hydrogen ultrapurification." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 23, no. 4 (November 24, 2021): 561–69. http://dx.doi.org/10.17308/kcmf.2021.23/3675.
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The purpose of the article is to reveal the role of the thickness of the layer of the lead-palladium alloy deposited on a copper-palladium membrane in the processes of cathodic injection and the anodic extraction of atomic hydrogen.The objects of the study were ~ 4 μm thick copper-palladium film electrodes obtained by magnetron sputtering of a target with a composition of 56 at. % Cu and 44 at. % Pd. The studies were carried out by cyclic voltammetry and double step anodic-cathodic chronoamperometry in a deaerated 0.1 М H2SO4 aqueous solution. The calculation of the parameters of hydrogen permeability for samples of finite thickness was carried out by mathematical modelling.Cathodic injection and anodic extraction of atomic hydrogen were used to study the effect of the surface modification of the foil membrane of a Pd-Cu solid solution on the diffusion and kinetic parameters of hydrogen permeability. It was found that even a small addition of Pd-Pb (a 2 nm thick film) leads to a decrease in the concentration of atomic hydrogen and the diffusion coefficient in the foil. With an increase in the thickness of the coating there is an increase in the diffusion parameters of the hydrogen injection and extraction processes. However, the hydrogen permeability does not reach the level of the unmodified alloy. The main kinetic parameter, the hydrogen extraction rate constant, changes nonlinearly with an increase in the thickness of the coating.
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Anderson, Ron, John Benedict, and Stanley J. Klepeis. "TEM microstructure of laser-trimmed Si-Cr devices." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 470–71. http://dx.doi.org/10.1017/s0424820100154329.
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Laser ablation adjustment of resistance values of resistors Incorporated within integrated circuits is common practice. We analyzed cross-section and plan-view Si-Cr laser ablated resistors in actual devices. Resistors were prepared as follows: nominally 500Å Si-Cr films were deposited on 2nd level quartz, patterned and then covered with 3rd level quartz. Oxygen was bled into the sputtering chamber during the Si-Cr deposition. No special heat-treatment was given to the Si-Cr resistors, but they did see 5-hours at 450C during the 3rd level quartz sputter. The resistors were contacted by 2-micron thick 2nd level Al-Cu metal stripes. The resistors were trimmed by focussed laser light impinging on the Si-Cr layer buried in SiO2. Trimming was accomplished, step-wise, using a YAG laser operating at different power settings. Plan-view samples were made by mechanically polishing to just above the resistor, inverting the sample, and mechanically polishing from the substrate side to just below the resistor. A copper microscope grid was epoxied on the thin specimen. After the two mechanical polishing operations, the sample was about one micron thick. Final thinning of the sample to about 0.5 μm was accomplished via a short ion-milling operation. Cross-sectioned samples are prepared the same way, taking care to have the final mechanical polishing operation terminate in the laser ablated area. No acids are used in either case. The samples see only acetone and water.
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Lakhera, Nishant, Emmanuel Labroye, Catherine Pronga, Florence Molinie, and Samuel Lesnakowski. "Reliability of Heavy Gage Aluminum Wire-bonds under High Temperature Aging." International Symposium on Microelectronics 2016, no. 1 (October 1, 2016): 000234–39. http://dx.doi.org/10.4071/isom-2016-wa54.
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Abstract Thick aluminum (Al) wedge bonds have been widely used in analog microelectronic packages due their lower cost, ease of use and excellent thermal and electrical performance. Reliability of thick Al wedge bonds on bare copper (Cu) leadframes under high temperature aging conditions has not been studied at a fundamental level in the past. This study investigates the reliability performance of Al wedge bonds on bare Cu surfaces under isothermal aging conditions specified by the automotive grade product qualification requirements. Results obtained show that Al/Cu intermetallic formed at the interface is detrimental to the mechanical and electrical package reliability. Plating on the leadframe has been evaluated as a potential mitigation to prevent intermetallic growth and hence improve the overall wedge bond and package reliability under high temperature reliability testing conditions. Significant improvement in the wedge bond and package reliability was achieved by using nickel plating under the wedge bonds. The results presented in this study can be used to design a more robust package capable of meeting stringent automotive grade requirements.
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Gernhardt, Robert, Friedrich Müller, Markus Woehrmann, Habib Hichri, Karin Hauck, Michael Toepper, Markus Arendt, and Klaus-Dieter Lang. "Ultra-fine Line Multi-Redistribution Layers with 10 μm Pitch Micro-Vias for Wafer Level and Panel Level Packaging realized by an innovative Excimer Laser Dual Damascene Process." International Symposium on Microelectronics 2017, no. 1 (October 1, 2017): 000120–25. http://dx.doi.org/10.4071/isom-2017-tp45_130.
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Abstract Multi-chip integrated Fan-Out packages and high I/O CSPs demands for higher routing density on wafer level. Due to that, the classical mask aligner lithography and photosensitive thin-film polymers used for BEOL reach its limits and new technologies and materials are necessary to generate lines and space down to two μm. These multi-metal layers set also higher demands on the mechanical properties of the materials. This paper presents a new excimer laser dual damascene process for ultra-fine routing for BEOL. Various materials like low cure temperature polyimide, BCB and 15-μm thick dry-film ABF material are structured by using an excimer laser stepper with a reticle mask to realize feature size below four μm with a high throughput. Micro-vias with a diameter below five μm are realized with high aspect ratio, which overcome the photolithographic limitations of the common used photosensitive thin-film polymers. The laser structuring allows to use innovative dielectric materials for WLP with optimized mechanical and electrical parameters for example inorganic filled polymers like dry-film ABF materials, which do not have to be photosensitive. The ablations depth per laser pulse and the cross-section of the ablated structures in dependence of the ablation parameters was investigated. The depth of embedded lines was set by number of pulses aside of integrated micro-vias. The lines and micro-vias were metallized with copper by galvanic process and the following CMP step removes the copper outside the ablated structures. The CMP removes only the copper and the metal of the seed-layer, which has the functions of an adhesion and barrier layer, stays intact. The under-etching of the conventional wet etch seed layer removal is a major problem for the fine line structures realized by the Laser Dual Damascene process. Due to that, the removal of the seed layer (usually titan) was investigated and it could be shown, that this layer can be removed by the excimer laser system. The stepper like system allows a sub-micron alignment accuracy with no need of a capture pad of the embedded lines. Test structures have been designed and fabricated with lines and spaces below 10 μm to demonstrate the dense multi-layer routing capability where the excellent reliability can be proven by air to air thermal cycling (from −55°C up to 125°C), current leakage and electro migration test.
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Fukunaka, Yasuhiro. "(Invited) Gravitational Level Effects on Electrochemical Interfacial Phenomena." ECS Meeting Abstracts MA2023-02, no. 66 (December 22, 2023): 3196. http://dx.doi.org/10.1149/ma2023-02663196mtgabs.
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Electrochemical copper refining technology invented in Niagara area made a great progress over more than 100 years through better understanding of natural convection phenomena. Ionic mass-transfer rate enhanced by natural convection developing along 1m high vertical electrode surfaces has been unconsciously utilized by trial-and-error method. As the local electrolyte composition is partly stratified in an electrolytic cell (roughly 5m long x 1.3m wide x 1.3m depth). The industrial electrolytic tank house is composed of about 1000 cells through which the electrolyte is continuously supplied. Thus, the electrolyte circulation is a key technology in industrial copper refining processes as well as appropriate selection of effective additive and stable sedimentation of anode slime containing precious metals on the electrolytic tank bottom. On the other hand, Cu nanowire arrays were electrodeposited potentiostatically with PC filter template in two kinds of electrolytic cell configurations: cathode over anode (C/A) and anode over cathode (A/C). The effect of gravitational level on the coupling phenomena between the morphological variation and the ionic mass transfer rate in nanosized pores(a mesoscopic scale of a fewμm high and 30nm in diameter) was also found. Hitherto, the coupling phenomena accompanied with the electrochemical interfacial reactions confined in such a mesoscopic space has not been studies in spite of the great technological interest for the production of micro- or meso-scale fabrication techniques encountered in microelectronics and energy conversion & storage technology field. The initial stage including nucleation and growth process during electrochemical phase transformation reactions must be at first focused to profoundly comprehend the present subject in order to reasonably design such an advanced device technology. Fundamental aspects in electrochemical processes in microgravity environments have not been frequently reported. However, Artemis projects may provide the large opportunities on the energy storage and power generation, as well as materials processing. The effects of gravitational level and magnetic field gradient on the electrochemical interfacial phenomena should be understood. The drop tower facility surely offers the appropriate & “unique” experimental opportunities to propose such research program in the future space engineering fields. Electrocrystallization of metals is selected as a good subject for starting direction of research. Its reaction mechanism is relatively simple, the deposition rate can be easily varied by changing the current density or potential, and a smooth copper film is deposited so long as it is not too thick. By the way, the damascene process has been introduced to copper wiring process in ULSI field by IBM almost 25 years ago. It is important to control the nucleation and crystal growth in the initial stages of electrodeposition process. For this purpose, many effects of additive have been intensively examined. However, few quantitative examinations have been reported on the coupling phenomena of ionic mass transfer and nucleation and crystal growth. In the present work, we introduce various gravitational levels as new parameters into the nonequilibrium electrochemical processing in order to create or tailor the unique physical properties in nano space field. It is fruitful in terms of physicochemical hydrodynamics that the experiments are done under various gravitational levels. In fact, it has been confirmed that the gravitational levels as well as the magnetic field introduce the intensified effects from that under 1 G normal environment. Here is a report to analyze the effect of gravitational level on the initial stages of Cu electrodeposition on TaN or TiN substrate.
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Boettcher, Lars, D. Manessis, S. Karaszkiewicz, A. Ostmann, and H. Reichl. "Next Generation System in a Package Manufacturing by Embedded Chip Technologies." Journal of Microelectronics and Electronic Packaging 7, no. 3 (July 1, 2010): 131–37. http://dx.doi.org/10.4071/imaps.261.
Full textAbstract:
The embedding of active and passive components offers a wide range of benefits and potentials. With the use of laminate based technology concepts, components can be moved from surface mount into the build-up layers of substrates by embedding and thereby the third dimension will be available for further layers or assemblies. This paper will briefly discuss the necessary process steps of the embedded chip technology and more importantly it will focus on new efforts to actually use chip embedding concepts for the realization of standard-type industrial quad flat packages with embedded chips (embedded chip QFN). Chips of 50 μm thickness, a pad pitch of 100 μm, and pad size of 85 μm are die bonded to a copper substrate and subsequently embedded in RCC (resin coated copper) layers by using vacuum lamination. The resulting QFN packages are only 160 μm thick and provide standard pads at 400 μm pitch and a total number of 84 I/Os with dimensions of 10 × 10 mm2. All embedded chip QFN packages at the prototype level are manufactured in 250 × 300 mm2 panels.
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Levson, Victor M. "Quaternary geology of the Babine porphyry copper district: implications for geochemical exploration." Canadian Journal of Earth Sciences 38, no. 4 (April 1, 2001): 733–49. http://dx.doi.org/10.1139/e00-102.
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The Quaternary stratigraphy of the Babine Lake region is characterized by a Late Wisconsinan succession of advance-phase glaciolacustrine sediments, glaciofluvial deposits, and till. Pollen data from a rare new interglacial site suggest a colder than present Middle Wisconsinan climate. Ice flow during the last glaciation was dominantly southeasterly, but in the Babine Range a regional, westerly ice-flow event occurred. Evidence for westerly flow diminishes eastward of Babine Lake, suggesting that the valley was near the eastward limit of an interior ice divide. Deglacial sediments include ice-marginal debris-flow, glaciofluvial, and glaciolacustrine sediments. Raised-delta elevations indicate that Glacial Lake Babine extended nearly 150 m above present lake level to 850 m asl, and higher, earlier phases may have existed locally. A variety of Holocene deposits cap the Quaternary succession. Glaciation has important implications for exploration in this copper-producing area. Southeasterly glacial dispersal patterns dominate, despite a regionally complex ice-flow history. Highly anomalous concentrations of copper occur in tills down-ice of most known bedrock copper occurrences, and a number of similarly anomalous till sites with no known copper sources have been identified in drift-covered areas. Exploration problems due to the thick and complex surficial cover can be overcome by selective sampling of basal tills, the composition of which clearly reflects the presence of buried mineral deposits. The effectiveness of till geochemistry as a method for locating buried mineralization in the region will be enhanced by careful selection of sample media and by a clear understanding of the glacial history.
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Lee, Chang-Chun, and Jing-Yan He. "Interactive Field Effect of Atomic Bonding Forces on the Equivalent Elastic Modulus Estimation of Micro-Level Single-Crystal Copper by Utilizing Atomistic-Continuum Finite Element Simulation." Molecules 25, no. 21 (November 3, 2020): 5107. http://dx.doi.org/10.3390/molecules25215107.
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This study uses the finite element analysis (FEA)-based atomistic-continuum method (ACM) combined with the Morse potential of metals to determine the effects of the elastic modulus (E) of a given example on atomic-level single-crystal copper (Cu). This work aims to overcome the estimated drawback of a molecular dynamic calculation applied to the mechanical response of macro in-plane-sized and atomic-level-thick metal-based surface coatings. The interactive energy of two Cu atoms within a face-centered metal lattice was described by a mechanical response of spring stiffness. Compared with the theoretical value, the parameters of the Morse potential dominated the predicted accuracy through the FEA-based ACM. Moreover, the analytic results indicated that the effective E of a single-crystal Cu was significantly sensitive to the given range of the interactive force field among atoms. The reliable elastic moduli of 86.8, 152.6, and 205.2 GPa along the Cu(100), Cu(110), and Cu(111) orientations of the Cu metal were separately acquired using the presented FEA-based ACM methodology.
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Boettcher, Lars, S. Karaszkiewicz, D. Manessis, and A. Ostmann. "Development of Embedded High Power Electronics Modules for Automotive Applications." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, DPC (January 1, 2013): 001717–43. http://dx.doi.org/10.4071/2013dpc-wp35.
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The automotive industry has a strong demand for highly reliable and cost-efficient electronics. Especially the upcoming generations of hybrid cars and fully electrical vehicles need compact and efficient 400 V power modules. Within the engine compartment installation space is of major concern. Therefore small size and high integration level of the modules are needed. Conventionally IGBTs and diodes are soldered to DCB (Direct Copper Bond) ceramics substrates and their top contacts are connected by heavy Al wire bonds. These ceramic modules are vacuum soldered to water-cooled base plates. Embedding of power switches, and controller into compact modules using PCB (Printed Circuit Board) technologies offers the potential to further improve the thermal management by double-sided cooling and to reduce the thickness of the module. In the recently started “HI-LEVEL” (Integration of Power Electronics in in High Current PCBs for Electric Vehicle Application) project, partners from automotive, automotive supplier, material supplier, PCB manufacturer and research teamed up to develop the technology, components and materials to realize high power modules. The following topics of the development will be addressed in detail in this paper:Assemble of power dies (IGBT and diode) using new sinter die attach materials:The deployment of new no pressure, low temperature sinter paste for the assembly of the power dies is a mayor development goal. Here the development of a reliable process to realize a defect free bonding of large IGBT dies (up to 10x14mm2) is essentially. These pastes are applied by stencil printing or dispensing and the sintering will take place after die placement at temperatures of around 200 °C.Thick copper substrate technology:To handle the high switching current, suitable copper tracks in the PCB are required. The realization of such thick copper lines (up to 1mm thickness) requires advanced processing, compared to conventional multilayer PCB production. In this paper the essential development steps towards a 10 kW inverter module with embedded components will be described. The process steps and reliability investigations of the different interconnect levels will be described in detail.
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Sergeev, N. N., A. N. Sergeev, S. N. Kutepov, A. E. Gvozdev, E. V. Ageev, and D. S. Klement'yev. "APPLICATION OF TECHNOLOGY IN THE PRODUCTION OF «CORTICAL» METHOD OF FORMING INSERTS FOR DIE CASTING COPPER ALLOYS." Proceedings of the Southwest State University 22, no. 3 (June 28, 2018): 67–83. http://dx.doi.org/10.21869/2223-1560-2018-22-3-67-83.
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In the present work for the creation of manufacturing technology forming statok higher heat resistance used the "cortical" method with the use of thermal spraying (TS). The essence of the method is as follows: on the model, which is a mirror copy of the forming surface of the insert, a working layer up to 3 mm thick of wear-resistant powder materials is applied by plasma spraying, and then a structural layer 10...20 mm thick of more plastic and cheap materials. The dusty "crust" process from which it will be established in a form holder, and separate from model. Working surface FV after separation from the model in size, shape and roughness fully complies with the requirements of the drawing, ie it is not subjected to additional processing. For reasons of availability and relatively low cost for the working layers forming inserts made of "cortical" method with the use of GTN, the most often used powders camofluage chromium-Nickel alloy ПН77Х15С3Р2 or metalloids brands ПН70Ю30 and ПН85Ю15. Research into the optimal composition of the mixture of powders ПН70Ю30 and ПН77Х15С3Р2 conducted on special samples of steel 45, which is a plate with dimensions 5050 mm around the perimeter with ribs protruding above the work surface to a height of 1 mm. working surface is chrome-plated and termoobrabotki to earn a guaranteed layer of Cr2O3, which provides the adhesive connection of the coating and the substrate at the level of 5 MPa. During the experiments, the composition of the mixture of powders ranged from 95% PN70YU30 + 5% PN77H15S3R2 to 70% PN70YU30 + 30% PN77H15S3R2 in steps of 5%. The coating produced according to the following mode: the current is 500 A, voltage - 60 V; the total consumption of powder - 1.5 kg/h; the sample temperature is 650 ℃; coating thickness - 0.5 mm. Deposited samples were placed in a muffle furnace and heated to a temperature of 1300 C, where they were kept for 1 hour. After cooling to room temperature, together with the furnace, the coatings were carefully separated from the samples and subjected to permeability tests for which they were placed in special containers smearing around the perimeter with special mastic. Then the coatings on the outside were covered with a layer of thick chalk, and kerosene was poured into the vessels. It is established that dusty coatings from a mixture of powders with a content of 20% or more of pn77h15s3r2 alloy practically do not have pores (kerosene within 24 hours did not penetrate the chalk-coated surface).
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Boettcher, Lars, A. Ostmann, D. Manessis, S. Karaszkiewicz, and H. Reichl. "Next Generation System in a Package Manufacturing by Embedded Chip Technologies." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, DPC (January 1, 2010): 002075–103. http://dx.doi.org/10.4071/2010dpc-tha13.
Full textAbstract:
The embedding of active and passive components offers a wide range of benefits and potentials. With the use of laminate based technology concepts, components can be moved from surface mount into the build-up layers of substrates by embedding and by that, the third dimension will be available for further layers or assemblies. This paper will briefly discuss the necessary process steps of the embedded chip technology and more importantly it will focus on new efforts to actually use chip embedding concepts for the realization of standard-type industrial Quad Flat Packages with embedded chips (embedded chip QFN). Chips of 50 μm thickness, a pad pitch of 100 μm and pad size of 85 μm are die bonded to a copper substrate and subsequently embedded in RCC (Resin-Coated-Copper) layers by using vacuum lamination. The resulting QFN packages are only 160 μm thick and provide standard pads at 400 μm pitch and a total number of 84 I/Os with dimensions of 10x10 mm2. All embedded chip QFN packages at prototype level are manufactured in 250x300 mm2 panels. The present work will include QFN package reliability results after extensive testing of thermal cycling, temperature humidity, high temperature storage and pressure cooker test. The investigation of new embedding material combinations is one task to provide a reliable package. The main focus here is on new materials that offer improved package stability and also the ability to embed dies of different thickness. Together with material suppliers improved resin formulations as well as the introduction of filler and glass fibers into the resin layers is currently realized and tested. In order to realize a further miniaturization ultra fine pitch (UFP) and fine line (UFL) approaches will be presented. For a UFP approach the goal is to develop the laser via technology further towards their limits as well as the investigation of new concepts. UFP requires the use of a semi additive patterning process. Here LDI processing is being used for all new generation chip embedded packages due to its potential for very fine copper patterning. Results on very fine L/S of 15–20μm will be shown based on the semi-additive processes on an ultra thin initial 1–2μm copper foil. Finally different applications will be presented. In an industrial cooperation different power package developments are ongoing. Here single and multi chips modules are realized as well as multiple routing layers. The combination of power and logic is one of the main challenges here, due to the need of thick copper layers for the power part and the more fine pitch demands for the controller chips. Process developments and results will be discussed in detail.
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Zhai, Yu, Ding Xu, and Yan Zhang. "Ka-Band Lightweight High-Efficiency Wideband 3D Printed Reflector Antenna." International Journal of Antennas and Propagation 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/7360329.
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This paper presents a lightweight, cost-efficient, wideband, and high-gain 3D printed parabolic reflector antenna in the Ka-band. A 10 λ reflector is printed with polylactic acid- (PLA-) based material that is a biodegradable type of plastic, preferred in 3D printing. The reflecting surface is made up of multiple stacked layers of copper tape, thick enough to function as a reflecting surface (which is found 4 mm). A conical horn is used for the incident field. A center-fed method has been used to converge the energy in the broadside direction. The proposed antenna results measured a gain of 27.8 dBi, a side lobe level (SLL) of −22 dB, and a maximum of 61.2% aperture efficiency (at 30 GHz). A near-field analysis in terms of amplitude and phase has also been presented which authenticates the accurate spherical to planar wavefront transformation in the scattered field.
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Kotliarenko, Alisa, Oscar Azzolini, Giorgio Keppel, Cristian Pira, and Juan Esposito. "Investigation of a Possible Material-Saving Approach of Sputtering Techniques for Radiopharmaceutical Target Production." Applied Sciences 11, no. 19 (October 3, 2021): 9219. http://dx.doi.org/10.3390/app11199219.
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Magnetron sputtering (MS) is a relatively new deposition technique, which is being considered among the cyclotron solid target (CST) manufacturing options now available, aiming at the medical radioisotopes yield for radiopharmaceutical production. However, the intrinsic high material losses during the deposition process do not permit its use with extremely expensive target materials, such as isotopically enriched metals/oxides. In this study, R&D technology for a new recovering shield is instead proposed to assess the dissipation of target material during the sputtering processes and, thus, an estimate of the material recovery that may be feasible and the related amount. The weight-loss analysis method is used to assess the material losses level inside the chamber during processing. In all tests carried out, a high-purity copper (99.99%) was used as a target material. As a result of this study, the material distribution for both magnetron and diode sputtering depositions can be calculated. The feasibility of the ultra-thick coatings growing, devoted to CST production, is demonstrated.
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Emon, Sharmin Zaman, Anowara Begum, Md Latiful Bari, and K. Siddique e. Rabbani. "In-vitro inactivation of Escherichia coli of surface water using metals." Bangladesh Journal of Microbiology 39, no. 2 (May 17, 2023): 54–59. http://dx.doi.org/10.3329/bjm.v39i2.66265.
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Technology for providing clean drinking water to remote areas of low-resource nations remains a significant challenge for human life The study aimed to develop a simple technology for rural households that might be adopted to utilize the bactericidal properties of metals. Three thick metal sheets made of copper, zinc, and brass (an alloy of copper and zinc) were used in this study work. These metallic sheets were placed in three plastic (polythene) containers with base areas 11cm x 7cm each so that the metallic sheets covered the entire base areas of the respective containers. Fifty ml, one hundred ml, and four hundred ml of contaminated water from a public pond were added to each container, covered with lids, and shaken/left undisturbed at room temperature. The microbial analysis of Total Aerobic Bacteria (TAB), Total Coliform Bacteria (TCC), and E. coli was done every 24 hours up to twenty-eight days of storage at room temperature. E. coli is considered an indicator of diarrhoeal pathogens. The initial bacterial counts were TAB: 4.22 log CFU/ml, TCC: 3.15 log CFU/ml, and E.coli: 3.13 log CFU/ml, respectively. TAB count did not reduce significantly for any of the metals used in this study. Total coliform counts decreased to almost half the original for all three metals in the first 24 hours but remained almost the same afterward. However, E.coli was inactivated entirely after treatment with copper within 24h and remained constant afterward. On the other hand, brass and zinc reduced E. coli by almost half in the first 24 hours but remained almost constant throughout the rest of the measured period. The findings mentioned above, a simple copper sheet might help inactivate diarrheal bacteria and provide safe drinking water within 24 hours. As a result, this may lead to the development of an easy technique to provide clean drinking water in remote areas of low-resource nations like Bangladesh. It is crucial to determine whether the level of copper in the water is within the safe range, as regular usage of higher doses might result in copper poisoning. A future study will attempt to optimize the relationship between the water volume to the copper sheet’s exposed surface area and the treatment time.
Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 54-59
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Welker, T., S. Günschmann, N. Gutzeit, and J. Müller. "Integration of Silver Heat Spreaders in LTCC utilizing Thick Silver Tape in the Co-fire Process." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, CICMT (September 1, 2015): 000062–66. http://dx.doi.org/10.4071/cicmt-tp13.
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The integration density in semiconductor devices is significantly increased in the last years. This trend is already described by Moore's law what forecasts a doubling of the integration density every two years. This evolution makes greater demands on the substrate technology which is used for the first level interconnect between the semiconductor and the device package. Higher pattern resolution is required to connect more functions on a smaller chip. Also the thermal performance of the substrate is a crucial issue. The increased integration density leads to an increased power density, what means that more heat has to dissipate on a smaller area. Thus, substrates with a high thermal conductivity (e. g. direct bonded copper (DBC)) are utilized which spread the heat over a large area. However, the reduced pattern resolution caused by thick metal layers is disadvantageous for this substrate technology. Alternatively, low temperature co-fired ceramic (LTCC) can be used. This multilayer technology provides a high pattern resolution in combination with a high integration grade. The poor thermal conductivity of LTCC (3 … 5 W*m−1*K−1) requires thermal vias made of silver paste which are placed between the power chip and the heat sink and reduce the thermal resistance of the substrate. The via-pitch and diameter is limited by the LTCC technology, what allows a maximum filling grade of approx. 20 to 25 %. Alternatively, an opening in the ceramic is created, to bond the chip directly to the heat sink. This leads to technological challenges like the CTE mismatch between the chip and the heat sink material. Expensive materials like copper molybdenum composites with matched CTE have to be used. In the presented investigation, a thick silver tape is used to form a thick silver heat spreader through the LTCC substrate. An opening is structured by laser cutting in the LTCC tape and filled with a laser cut silver tape. After lamination, the substrate is fired using a constraint sintering process. The bond strength of the silver to LTCC interface is approx. 5.6 MPa. The thermal resistance of the silver structure is measured by a thermal test chip (Delphi PST1, 2.5 mm × 2.5 mm) glued with a high thermal conducting epoxy to the silver structure. The chip contains a resistor and diodes to generate heat and to determine the junction temperature respectively. The backside of the test structure is temperature stabilized by a temperature controlled heat sink. The resulting thermal resistance is in the range of 1.1 K/W to 1.5 K/W depending on the length of silver structure (5 mm to 7 mm). Advantages of the presented heat spreader are the low thermal resistance and the good embedding capability in the co-fire LTCC process.
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MOURIER, Thierry, Stephane Minoret, Sabrina Fadloun, Larissa Djomeni, Sylvain Maitrejean, Steve Burgess, Andy Price, Chris Jones, Anne Roule, and Laurent Vandroux. "Low temperature MOCVD TiN barrier deposition for high aspect ratio TSVs : A solution for 3D integration." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, DPC (January 1, 2013): 001322–42. http://dx.doi.org/10.4071/2013dpc-wp12.
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In recent years, 3D integration has become an alternative solution to the “More Moore” concept for providing circuits with higher performance or increased functionality. Via-Middle TSV is considered a reference integration scheme and requires void-free copper fill of very high aspect ratio TSVs. Metallization of such structures, in particular barrier and seed layer deposition, becomes a critical process step as barrier material to copper diffusion must provide good efficiency to copper diffusion for further integration and especially on TSV sidewalls, requiring sufficient step coverage. Ionized PVD is today widely extended from BEOL to TSV metallization. This technique has, however , several limitations for 3D integration coming from its poor step coverage in 10:1 aspect ratio features thus requiring thick material deposition to cover sidewalls which will lead to expensive process both for deposition and further CMP steps and high stress leading to adhesion issues. Considering the maturity level of the alternative processes, MOCVD metallization appears to be a very promising Solution. MOCVD TiN layers have been widely reported to provide excellent step coverage and diffusion barrier efficiency in BEOL processes. The presented study describes a process based on an MOCVD TiN deposition that can be performed from 175 to 400 °C. This polyvalent process can be performed for anytype of 3D integration from Mid process TSVs where performance is the key factor to Via last integration for which low temperature and low cost processes are required. The paper will first discuss the process development and characterization of this material with particular focus on key parameters for 3D integration. In addition, film integration in Via-Middle TSVs will be described, comparing step coverage performance in high aspect ratio TSVs with the I-PVD reference process. Then, electrical measurements of daisy chains and interconnect lines from a 300 mm 3D demonstrator will be presented.
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Hofmann, Christian, Maulik Satwara, Martin Kroll, Sushant Panhale, Patrick Rochala, Maik Wiemer, Karla Hiller, and Harald Kuhn. "Localized Induction Heating of Cu-Sn Layers for Rapid Solid-Liquid Interdiffusion Bonding Based on Miniaturized Coils." Micromachines 13, no. 8 (August 12, 2022): 1307. http://dx.doi.org/10.3390/mi13081307.
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Considering the demand for low temperature bonding in 3D integration and packaging of microelectronic or micromechanical components, this paper presents the development and application of an innovative inductive heating system using micro coils for rapid Cu-Sn solid-liquid interdiffusion (SLID) bonding at chip-level. The design and optimization of the micro coil as well as the analysis of the heating process were carried out by means of finite element method (FEM). The micro coil is a composite material of an aluminum nitride (AlN) carrier substrate and embedded metallic coil conductors. The conductive coil geometry is generated by electroplating of 500 µm thick copper into the AlN carrier. By using the aforementioned micro coil for inductive Cu-Sn SLID bonding, a complete transformation into the thermodynamic stable ε-phase Cu3Sn with an average shear strength of 45.1 N/mm2 could be achieved in 130 s by applying a bond pressure of 3 MPa. In comparison to conventional bonding methods using conduction-based global heating, the presented inductive bonding approach is characterized by combining very high heating rates of about 180 K/s as well as localized heating and efficient cooling of the bond structures. In future, the technology will open new opportunities in the field of wafer-level bonding.
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Birsan, D. C., and G. Simion. "Numerical Modelling of Thermo-Mechanical Effects Developed in Resistance Spot Welding of E304 Steel with Copper Interlayer." Annals of Dunarea de Jos University of Galati. Fascicle XII, Welding Equipment and Technology 33 (December 15, 2022): 89–94. http://dx.doi.org/10.35219/awet.2022.07.
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Resistance spot welding is a technique applied to join two or more similar or dissimilar metals, by applying pressure and electric current to the spot-weld area. Based on the electrical resistance property of metals, a great amount of heat is generated and used to carry out materials joints, by creating a molten metal nucleus between the components to be welded. The influence of an interlayer material, positioned between the parent materials, on the strength of similar or dissimilar welded joints was studied by researchers worldwide. In most cases, by optimising the process parameters, an increase in the welded joint strength was achieved. In this paper, the resistance spot welding of 1mm thick E304 stainless steel sheets, both with and without a copper foil interlayer, was investigated, by applying, in all cases, the same process parameters. The tensile test of the joints showed a decrease in the strength of joints performed with interlayer metal. A method to control the deterioration level of the joint’ mechanical properties is the Finite Element Analysis which allows to optimise the process parameters so that the negative effects of the process on the joint quality to be limited. It was found that an increase in amperage is needed to compensate for the addition of the interlayer metal and to obtain an adequate melting in the spot-weld area. This modification causes an increase of the molten core diameter that will lead to improvement of the welded joint strength, while no significant influence on the internal stress level was noticed in the processing and numerical analysis of the output data.
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Wentlent, Luke A., James Wilcox, and Mohammed Genanu. "Applicability of Selective Laser Reflow for Thin Die Stacking." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000741–47. http://dx.doi.org/10.4071/2380-4505-2018.1.000741.
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Abstract A 3-D packaging approach such as die stacking is an attractive way to package greater functionality and performance into a smaller footprint, often at a reduced overall product cost. Achieving such 3-D integration can however place significant demands on the manufacturing process, often requiring substantial production expense to bond multiple die in a sequential manner. One alternative, potentially offering significant throughput, is the use of selective laser reflow to bond stacked die. This process produces a localized heating of the stacked die sufficient to produce soldered interconnects at the bonding interface but with very short exposure times that minimize the heating of other parts of the assembly and decrease the overall duration of the bonding process. The use of a commercial infrared (IR) laser reflow instrument for the sequential attachment of thin die into a 3-D stack was considered. The bonding technology under study consists of an infrared laser coupled with a custom optics system that allows the laser beam to be shaped into a range of rectangular shapes and sizes. This allows for a single device or target area to be selectively heated and reflowed while other regions in the near vicinity are not. The target reflow area is exposed to a shaped laser beam for a combination of laser powers and exposure times according to the desired thermal profile. The top most materials absorb the IR energy of the incident laser and conduct that thermal energy down to the solder joints and into rest of the assembly. The rates of heat transfer realized depend significantly upon the sample geometry and material composition. Since this produces a highly accelerated reflow, typically 2–8 seconds, the entire process is highly transient in nature. This paper reports on the investigation into the utility of a selective area laser reflow process to sequentially bond thin die into a multi-chip stack. Thin silicon die (~60μm thick) were bonded to a 150μm thick laminate substrate using a selected area laser reflow process. The die interconnects were formed through the soldering of SnAg capped copper pedestals under the local laser heat. First level die were placed onto copper pads on the laminate and then bonded using the laser process. Subsequent die (2nd level) were placed on and bonded to gold plated nickel pad sites on the top of the first level die. At each step of the process the quality of the solder interconnects was examined using optical and electron microscopy. A range of laser profiles were utilized with several different thermal parameters: peak temperatures ranging from 235–255°C, time above liquidus between 1–3 seconds, and a fixed cooling rate of 40°C/s. Control samples of stacked die were assembled using conventional manufacturing techniques to enable direct comparisons of the interconnects and die bonding characteristics.
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Chen, Scott, Simon Wang, Coltrane Lee, and John Hunt. "Low Cost Chip Last Fanout Package using Coreless Substrate." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, DPC (January 1, 2015): 000272–300. http://dx.doi.org/10.4071/2015dpc-ta24.
Full textAbstract:
Smart phones & other portable devices have dominated Semiconductor growth, and drive IC packages smaller, lighter & thinner, but at the same time they continue to integrate more functions in that smaller volume. Besides SOC solutions driven by design houses or system companies, we have seen more packages of Quad Flat Non-lead (QFN), wafer level CSP (WLCSP), fan out WLCSP (FOWLP) and system in package (SIP) being widely used in these smart phones & mobile devices. Two factors have driven a new package technology within the last 10 years. One is the advancing technology nodes which allow the shrinkage of die, allowing more die per wafer. However this comes at the cost of reduced package area for I/Os such as solderball interconnects. The second factor also relates to the advancing technology nodes. Not all silicon functionality benefits from there advanced nodes, and merely adds to the cost of the die. This has driven the partitioning of device functionality into multiple die, which in turn requires effective interconnection of these partitioned die. The packaging technology that has evolved to solve these two situations has been Fan Out Wafer Level Packaging (FOWLP). The typical FOWLP uses chip first processing, in which the bare die is molded into a wafer shaped carrier with die pads exposed. Typically sputtering is used to provide interconnects to the die pad followed by patterned electroplating of redistribution lines (RDL) to “Fan Out” the next level interconnect pads to regions that can extend on to the molded material beyond the die perimeter. These processes require the use of relatively expensive semiconductor front end classes of equipment and are tailored to handle the reconstituted molded plastic wafers. We will describe a relatively low cost alternative to FOWLP, which meets the needs of a large percentage of the applications requiring a packaging technology such as FOWLP. This new package uses a “Chip Last” approach to the problem of increasing useable interconnect pad area. Die which have been bumped with Copper(Cu) Pillars are mass reflowed onto a low cost coreless substrate, followed by over molding which also serves as the die underfill. The Cu pillars allow direct connection to die pads at 50 μm pitch or below, negating the requirement for RDL formation on the die. The use of embedded traces allows for fine lines and spaces down to 15μm or less, and bonding directly on to the bare Copper. The Cu Pillars are bonded to one side of the Copper trace, and the solderballs or LGA pads are directly on the opposite side of the Copper. This makes the substrate to be effectively only as thick as the Copper used in the traces, and allows the final package to be as thin as 400μm. All previous FOWLP designs at ASE were able to be routed in a single layer using this new packaging technology . Since this uses existing high volume packaging infrastructures, more complex assemblies including multiple die, inclusion of passive components, and 3D structures can be easily implemented.
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Chang, Y. J., and D. Kuhlmann-Wilsdorf. "Effects of Ambient Gases on Friction and Interfacial Resistance." Journal of Tribology 110, no. 3 (July 1, 1988): 508–15. http://dx.doi.org/10.1115/1.3261660.
Full textAbstract:
As is well known, ambient atmospheres can greatly affect the friction and wear behavior of metals sliding on each other, as well as the electric contact resistance between the metals. In order to better understand the mechanisms of those effects of ambient atmospheres, the coefficient of friction and the electric contact resistance have been studied for bundles of 50 micrometer thick copper wires, sliding on a polished copper surface in a specialized apparatus, called the hoop apparatus. The ambient gas was cycled between laboratory air and carbon dioxide, and between laboratory air and argon, respectively. The results indicate a reversible build-up and removal of surface films whose nature as well as speed of formation and removal depends on the gas present. Fiber bundles are used in order to eliminate the constriction resistance, so that the contact resistance is directly proportional to the specific film resistivity. The following properties were found to be affected by the ambient gases. (i) The average level of the contact resistance. (ii) The amplitude of the electric “noise.” (iii) The coefficient of friction. (iv) The difference between the static and the dynamic coefficients of friction in stick-slip motion. The results were found to be consistent with previous measurements in which the mechanism of forming wear particles was deduced from a wear chip analysis. Correspondingly they were interpreted in terms of the same wear model. This led to a further advance in the understanding of the interfacial processes accompanying sliding in this sample/substrate combination.
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Pollard, Kimberly D., Nichelle Gilbert, Don Pfettscher, and Spencer Hochstetler. "Proven Cleaning Technology Solutions for Lead-Free Micro-Bumping Processes." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, DPC (January 1, 2012): 002399–427. http://dx.doi.org/10.4071/2012dpc-tha24.
Full textAbstract:
Opportunities for developing new and enabling packaging schemes are being pursued as part of device improvement strategies for electronic products. Processes such as embedded technologies in wafer level packaging and 3-D chip architecture schemes open up opportunities for realization of a variety of package configurations. As a result, there are many opportunities to impact both device performance and the processes used to create them. In the area of electroplated solder application, one area of growing interest is cleaning technology. There is a need for an integrated process to fabricate defect-free copper pillars with lead-free caps and lead-free solder plated bumps compatible with advanced packaging schemes and with improved yields and reliability. Photoresist removal and surface preparation have been identified as critical to the success. In familiar and widespread technology using 150 micropitch solder bumping, the introduction of RoHS rules for lead-free solder bump compositions, (SnAg, SnAgCu), proceeded in the absence of an integrated and tailored process capable of defect-free surface preparation. It was relatively simple for solder bump compositions in many devices to be converted to lead-free alloys. However, new challenges continue to arise in higher volume fabrication of SnAg micro-pillars (micro-pillars) or copper micro-pillars with lead-free solder caps as the bump pitch approaches 25 microm with aspect ratios of 1:1 or 1.5:1. Individual processes that are involved in the total integration, including (1) dielectric cleaning steps, (2) PVD seed Ti and Cu deposition, (3) electroplating, (4) thick photoresist application and patterning, (5) photoresist removal, (6) associated descum processes, and (7) copper seed metal etch steps, have been challenged to meet the demands. New geometries, higher aspect ratios and very dense solder bump arrays have created further challenges for these processes, stretching the older 150 microm technology beyond its capability. The focus of this paper is to identify a reliable route to defect-free copper micro-pillars with lead-free caps and lead-free solder plated micro-bumps after photoresist removal in applications compatible with advanced packaging schemes and with improved yields and reliability.
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Popov, Petko, Tudor Berza, Alexander Grubic, and Dumitru Ioane. "Late Cretaceous Apuseni-Banat-Timok-Srednogorie (ABTS) magmatic and metallogenic belt in the Carpathian-Balkan orogen." Geologica Balcanica 32, no. 2-4 (December 30, 2002): 145–63. http://dx.doi.org/10.52321/geolbalc.32.2-4.145.
Full textAbstract:
The Apuseni-Banat-Timok-Srednogorie (ABTS) Magmatic and Metallogenic Belt can be traced from the Apuseni Mountains in the north, through the western part of the South Carpathians (Banat) in Romania, the Timok region in East Serbia, the Srednogorie zone (Bulgaria) and continues in Turkey through the Black Sea. The basement belongs to the southern margin of the European continent. The ABTS Belt is unconformly superimposed on older structures, including the Early Cretaceous ones. Furthermore, it crosses the Vardar ophiolite suture in the Mures and Voevodina regions. These facts indicate a new stage in the alpine evolution which followed the subduction of the Vardar Ocean and subsequent collision. This new stage was characterized by an extensional geodynamic regime. The ABTS arcuate rift was formed as a result of postcollisional orogenic collapse. The Late Cretaceous magmatic activity with submarine volcanic rocks and comagmatic intrusions began during the Cenomanian and ended during the Maastrichtian. Volcanic and associated predominantly flysch-type sedimentary deposits form a 2-3 to 7-8 km thick pile. The magma generation in ABTS extensional belt was realized in different depth level, which determines differences of melt compositions. Rock association of calc-alkaline, tholeitic, subalkaline and alkaline series are established. The petrologic features of the alkaline and subalkaline rocks and several Sr isotope analyses show the mantle origin of the parent magma. The calc-alkaline magma was generated predominantly around the boundary between mantle and lower crust. Porphyry copper and copper massive sulphide deposits are the most important. Some of them have an economical content of gold and/or molybdenum. There are skarn and vein type copper deposits, too. Other important deposits are iron, tungsten-molybdenum and lead-zinc skarn deposits. Besides, small hydrothermal base metal-gold, barite, porphyry gold, silver and volcano-sedimentary iron-manganese deposits are known. The plutonic, subvolcano-plutonic, volcano-plutonic, volcano-subvolcanic and volcanic ore-bearing structures are distinguished. The geochemical associations show the predominance of mantle sources of the ore-forming fluids.
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Wojcik, Mariusz, Dariusz Witek, Tomasz Klej, and Edward Ramotowski. "Embedding components in voltage converter PCB for size reduction and heat management." Circuit World 42, no. 1 (February 1, 2016): 17–22. http://dx.doi.org/10.1108/cw-10-2015-0048.
Full textAbstract:
Purpose – The purpose of this paper was to show physical limitation of embedding standard packaging components into printed circuit board (PCB) which is more reasonable technology for small series productions which is popular in industrial products. Embedding electronic components inside a PCB FR-4 substrate leads to significant size reduction and better heat management. Embedded chip technology is already known in many consumer electronics applications, but it is focused on high volumes and required to order components ready to be embedded. Design/methodology/approach – Highly integrated DC/DC converter with standard-package electronic parts (passive and active) was embedded inside a PCB structure. The design and the manufacturing process was based on standard PCB FR-4 technology. Sandwich solution was used to integrate all layers together; one of the main investigations was to focus on how to fill space around components to keep internal stresses on very low level. Findings – There were few considerations during choosing the right concept. The first, which occurred during the first producing round, was the distance between thick copper and inner layer. The second one was the way how to fill space between mounted components on inner layer and isolation laminate. A few trials took place and it is decided that it is impossible to fill this space with resin from prepregs; therefore, a casting compound was used. Originality/value – Design and manufacturing process which brings 37 per cent of size reduction of complete DC/DC voltage converter PCB with 28.5 W output power comparing to a reference design with standard surface mounted devices (SMD) and copper layout implementation has been achieved during research project.
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Mathew, Varughese, Sheila Chopin, Oliver Chyan, Nick Ross, Alex Lambert, and Muthappan Asokan. "Aluminum bond pad corrosion of wirebond packages." International Symposium on Microelectronics 2016, no. 1 (October 1, 2016): 000227–33. http://dx.doi.org/10.4071/isom-2016-wa53.
Full textAbstract:
Abstract Corrosion of aluminum bond pads in wirebonded packages can lead to device reliability issues under the harsh conditions in automotive applications. Corroded Al (aluminum) surface forms a mud-crack type appearance with a relatively very thick aluminum oxide/hydroxide (> 0.1μm) compared to thin protective native aluminum oxide (< 7nm). Various factors contributing to the formation of mud-crack type corrosion are identified. In all cases of mud-crack corrosion observed for packaged devices, Cl (chlorine) was detected on the corroded Al pad. The corrosive impact of high levels of Cl on the Al pad resulting in thick aluminum oxide growth will be discussed. The concentration levels of Cl to form mud-crack corrosion is far beyond the level of ionizable Cl typically present in packaging materials (such as mold compound or organic die attach) so the source of high levels of Cl is due to foreign contamination. The effect of Cl on mud-crack corrosion depends on other factors including pH and applied bias voltage. Corrosion susceptibility is found to be significantly reduced, even in the presence of high levels of Cl, when the pH > 6 and close to the neutral value of a pH of 7. It was also found that Cl is not essential to form mud-crack corrosion. Conditions leading to the corrosion in the absence of Cl are presented. F (fluorine) is a known contaminant in semiconductor processing and its influence on Al pad corrosion is examined. The differences on the impact of F vs. Cl on mud-crack corrosion will be discussed. Corrosion was observed irrespective of the wirebonds in the package (gold (Au) or copper (Cu)). However, the type of bi-metallic contact influences the extent of corrosion. The impact of bi-metallic contact on the mud-crack corrosion will be presented.
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Willan, Robert C. R. "Structural setting and timing of hydrothermal veins and breccias on Hurd Peninsula, South Shetland Islands: a possible volcanic-related epithermal system in deformed turbidites." Geological Magazine 131, no. 4 (July 1994): 465–83. http://dx.doi.org/10.1017/s0016756800012103.
Full textAbstract:
AbstractQuartz veins and vein-breccias in a greywacke-shale sequence of ?Carboniferous-Triassic age were previously regarded as mesothermal silicified fault breccias, and related to an adjacent Eocene granodiorite pluton. New mapping of vein assemblages and textures, and their structural and cross-cutting relationships, demonstrates that the steeply dipping, sheeted, epithermal-textured vein array was hydraulic in origin and possibly Cretaceous in age. The main vein and breccia swarm trends for 14 km NNE along-strike and 2 km across-strike, cutting large irregular areas of silicified and brecciated sandstone, and patchy areas of pyritic, propylitic and K-feldspar alteration. Angular vein fabrics and hydraulic disruption textures indicate wedging by hydrothermal solutions, hydraulic rupture, brecciation and fragment transport, followed by open-space precipitation, in veins generally < 15 cm thick and breccias up to a few metres thick. Hydrothermal quartz, chlorite, calcite and chalcedony predominate, with variable amounts of chalcopyrite, galena, sphalerite and pyrite. Epidote, arsenopyrite, K-feldspar and andradite garnet are conspicuous in places. Breccias were pre-and syn-mineralization, whereas mineral precipitation was pre-, syn- and post-breccia formation. Hydrothermal activity was simultaneous with extensional faulting, striking NNE, and accompanied by intrusion of dacitic dykes. There followed conjugate shearing on east- and ESE-striking faults, intrusion of high-level tonalite stocks, and several phases of basaltic andesite dyke intrusion. These hypabyssal rocks were probably coeval with the Antarctic Peninsula Volcanic Group dominating Livingston Island, dated between 130 and 75 Ma. Minor copper and iron sulphide-bearing veins occur in adjacent volcanic and hypabyssal intrusive rocks. The Hurd Peninsula veins may, therefore, form part of a volcanic-epithermal hydrothermal system (adularia-sericite-quartz type), of Cretaceous age, rather than a porphyry-related system of Eocene age.
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Langer, Gregor, Markus Leitgeb, Johann Nicolics, Michael Unger, Hans Hoschopf, and Franz P. Wenzl. "Advanced Thermal Management Solutions on PCBs for High Power Applications." Journal of Microelectronics and Electronic Packaging 11, no. 3 (July 1, 2014): 104–14. http://dx.doi.org/10.4071/imaps.422.
Full textAbstract:
With increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to rapid advances in semiconductor technology, particularly in the field of high-power components, the temperature distribution inside of a component is a critical parameter of long-term reliability and must be carefully considered during the design phase. Two main drivers in the electronics industry are miniaturization and reliability. Whereas there is a continuous improvement concerning miniaturization of conductor tracks (i.e., lines and spaces have been reduced continuously over the past years), miniaturization of the circuit carrier itself, however, has mostly been limited to decreased layer counts and base material thickness. This can lead to significant component temperature increase and thence to accelerated system degradation. Enhancement of the system reliability is directly connected to an efficient thermal management on the PCB level. There are several approaches that can be used to address this issue: optimization of the board design, use of base materials with advanced thermal performance, and use of innovative buildup concepts. The paper provides a short overview about standard thermal solutions such as thick copper, thermal vias, plugged vias, or metal core based PCBs. Furthermore, attention will be focused on the development of copper filled thermal vias in thin board construction. In another approach, advanced thermal management solutions are presented at the board level, exploring different buildup concepts (e.g., cavities). Advantages of cavity solutions in the board are shown that not only decrease the thermal path leading from the high power component through the board to the heat sink, but also have an impact concerning the mechanical miniaturization of the entire system (reduction of z axis). Such buildups serve as a favorable packaging solution with promising thermal performance. Moreover, using thermal simulations different setups are compared and a deeper insight into the thermally relevant geometry and material parameters is provided, allowing production efforts to be reduced and to offering optimized designs and board buildups.
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Chen, Scott, Simon Wang, Coltrane Lee, Adren Hsieh, John Hunt, and William Chen. "Chip Last Fan Out as an Alternative to Chip First." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000245–50. http://dx.doi.org/10.4071/isom-2015-wa33.
Full textAbstract:
Smart phones & other portable devices have dominated Semiconductor growth, and drive IC packages smaller, lighter & thinner, and they continue to integrate more functions in that smaller volume. Besides SOC solutions driven by design houses or system companies, we have seen more packages of Quad Flat Non-lead (QFN), wafer level CSP (WLCSP), and system in package (SIP) being widely used in these smart phones & mobile devices.. Fan out WLCSP (FOWLP) has great potential to be the next new package for the smart phone mobility application. Two factors have driven fan out WLCSP (FOWLP) package technology in the last few years. The first is the advancing technology nodes which allow the shrinkage of die, allowing more die per wafer. However this comes at the cost of reduced package area for I/Os such as solder ball interconnects. The second and potentially more important factor relates to the demand of the market for more functions. Not all silicon functionality benefits from these advanced nodes, and merely adds to the cost of the die. This has driven the designers to partitioning of desired functionality into multiple die, which in turn requires effective interconnection of these separate die. The packaging technology that has evolved to solve these two situations has been Fan Out Wafer Level Packaging (FOWLP). Up to date FOWLP used chip first processing, in which the bare die was molded into a wafer shaped carrier with die pads exposed. Typically sputtering is used to provide interconnects to the die pad followed by patterned electroplating of redistribution lines (RDL) to “Fan Out” the next level interconnect pads to regions that can extend on to the molded material beyond the die perimeter. These processes require the use of relatively expensive semiconductor front end classes of equipment and are tailored to handle the reconstituted molded plastic wafers. We will describe a new alternative to chip first FOWLP, an alternative which meets the needs of a large percentage of the applications requiring a packaging technology such as FOWLP. This new package has been in production in ASE for over a year, and uses a “Chip Last” approach to the problem of increasing useable interconnect pad area. Die which have been bumped with Copper(Cu) Pillars are mass reflowed onto a low cost coreless substrate, followed by over molding which also serves as the die underfill. The Cu pillars allow direct connection to die pads at 50 μm pitch or below, negating the requirement for RDL formation on the die. The use of embedded traces allows for fine lines and spaces down to 15μm or less, and bonding directly on to the bare Copper. The Cu Pillars are bonded to one side of the Copper trace, and the solderballs or LGA pads are directly on the opposite side of the Copper. This makes the substrate to be effectively only as thick as the Copper used in the traces, and allows the final package to be as thin as 400μm. Since this uses existing high volume packaging infrastructures, more complex assemblies including multiple die, inclusion of passive components, and 3D structures can be easily implemented. We have designated this package structure “Fan Out Chip Last Package (FOCLP)” For higher end applications we will show the ability to use a high density substrate process for use in more demanding chip last fan out packages
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Panaskar, Nitin, and Ravi Prakash Terkar. "Optimization of friction stir welding process parameters for AA6063-ETP copper using central composite design." World Journal of Engineering 17, no. 4 (May 11, 2020): 491–507. http://dx.doi.org/10.1108/wje-11-2019-0322.
Full textAbstract:
Purpose Recently, several studies have been performed on lap welding of aluminum and copper using friction stir welding (FSW). The formation of intermetallic compounds at the weld interface hampers the weld quality. The use of an intermediate layer of a compatible material during welding reduces the formation of intermetallic compounds. The purpose of this paper is to optimize the FSW process parameters for AA6063-ETP copper weld, using a compatible zinc intermediate filler metal. Design/methodology/approach In the present study, a three-level, three-factor central composite design (CCD) has been used to determine the effect of various process parameters, namely, tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil on ultimate tensile strength of the weld. A total of 60 experimental data were fitted in the CCD. The experiments were performed with tool rotational speeds of 1,000, 1,200 and 1,400 rpm each of them with tool traverse speeds of 5, 10 and 15 mm/min. A zinc inter-filler foil of 0.2 and 0.4 mm was also used. The macrograph of the weld surface under different process parameters and the tensile strength of the weld have been investigated. Findings The feasibility of joining 3 mm thick AA6063-ETP copper using zinc inter-filler is established. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9759 and model F-value of 240.33. A good agreement between the prediction model and experimental findings validates the reliability of the developed model. The tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil significantly affected the tensile strength of the weld. The optimal conditions found for the weld were, rotational speed of 1,212.83 rpm and traverse speed of 9.63 mm/min and zinc foil thickness is 0.157 mm; by using optimized values, ultimate tensile strength of 122.87 MPa was achieved, from the desirability function. Originality/value Aluminium and copper sheets could be joined feasibly using a zinc inter-filler. The maximum tensile strength of joints formed by inter-filler (122.87 MPa) was significantly better as compared to those without using inter-filler (83.78 MPa). The optimum process parameters to achieve maximum tensile strength were found by CCD.
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Mathew, Varughese, and Sheila Chopin. "Corrosion reliability of copper wirebond (CuWB) packages-Impact of voltage and corrosive ions from packaging materials." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000286–91. http://dx.doi.org/10.4071/isom-2015-wa51.
Full textAbstract:
Reliability of electronic devices used in extreme and harsh conditions such as in automotive applications is often associated with prevention of corrosion at the interfaces of dissimilar interconnect metals and of metal (Al or Cu) bonding pads. Packaging materials, especially molding compounds, contain several ionic components and can uptake certain level of moisture to provide electrolytic conditions to initiate corrosion processes. Probability of occurrence of corrosion in devices with high voltage applications is of special interest as many analog devices operates at higher voltages and with new CuWB packages there is a higher susceptibility of corrosive failures. This paper examines the impact of voltage on the mold compound compatibility with CuWB packages up to 65 V. Bias HAST reliability evaluation of various mold compounds at different voltages will be described. Corrosion of bonding pad (Al) and at the Al-Cu intermetallic compound interface was observed in the presence of certain ions present in mold compounds. Even though current mold compounds are “green”, the allowable amounts of halide ions can far exceed the ppm limit to prevent CuWB corrosive failures. Bromide ions are known to be very corrosive to metals. Br ions are still present in some mold compounds. The impact of the Br ion on CuWB reliability will be described. Additive impact of Br ions in presence of Cl will be examined. Another corrosive component present in many mold compounds, sulfur compounds, also can be corrosive under certain reliability stress conditions. Difference in corrosion behavior of Cu and Pd –Cu wirebonded packages due to sulfur compounds will be presented. Corrosive impact of high levels of Cl on the Al pad corrosion leading thick aluminum oxide growth and reliability failures will be discussed.
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Burrows, David R., Michael Rennison, David Burt, and Rod Davies. "The Onto Cu-Au Discovery, Eastern Sumbawa, Indonesia: A Large, Middle Pleistocene Lithocap-Hosted High-Sulfidation Covellite-Pyrite Porphyry Deposit." Economic Geology 115, no. 7 (November 1, 2020): 1385–412. http://dx.doi.org/10.5382/econgeo.4766.
Full textAbstract:
Abstract In 2013, a diamond drill program tested an extensive advanced argillic alteration lithocap within the Hu’u project on eastern Sumbawa Island, Indonesia. A very large and blind copper-gold deposit (Onto) was discovered, in which copper occurs largely as disseminated covellite with pyrite, and as pyrite-covellite veinlets in a tabular block measuring at least 1.5 × 1 km, with a vertical thickness of ≥1 km. Copper and gold are spatially related with a series of coalesced porphyry stocks that intrude a polymictic diatreme breccia capped by a sequence of intramaar laminated siltstones, volcaniclastic and pyroclastic rocks, and overlain by andesite flows and domes. The porphyry intrusions were emplaced at shallow depth (≤1.3 km), with A-B–type quartz veinlet stockworks developed over a vertical interval of 300 to 400 m between ~100 and 500 m below sea level (bsl), 600 to 1,000 m below the present surface, which is at 400 to 600 m above sea level. In the area drilled at Onto, the diatreme breccia, all porphyry intrusions and, to a lesser extent, the surrounding older andesite sequence have all been overprinted by intense subhorizontal advanced argillic alteration, zoned downward from illite-smectite, quartz-dickite to quartz-alunite and quartz-pyrophyllite ± diaspore alteration. The alteration package includes two particularly well-developed zones of residual quartz with vuggy texture in subhorizontal zones at shallow depth, the upper one is still porous but the lower horizon, ~100 m thick, is largely silicified and is located at or near the top of the quartz-alunite alteration. Mineralization starts below the lowermost silicic horizon with more than 90% of the current resource in quartz-pyrophyllite-alunite and quartz-alunite alteration. Mineralization is dominated by a high-sulfidation assemblage of covellite-pyrite ± native sulfur largely in open-space fillings and replacements, but also as discrete pyrite-covellite and covellite only veins down to at least 1 km. Although the greatest amount of copper occurs as paragenetically late covellite deposited during formation of the advanced argillic alteration, approximately 60% of resource at 0.3% Cu cutoff still occurs within the porphyry stocks, indicating the porphyry stocks are a fundamental control on mineralization. There is considerable remobilization and dispersion of copper and, to a lesser extent, gold into the surrounding pre-mineral breccia and the late intermineral intrusions from the two earliest porphyry phases, resulting in quite consistent copper and gold grades throughout the currently delineated mineral resource. The very high sulfidation state of the mineralization is thought to be a consequence of the metal-bearing ore fluids cooling in the advanced argillic-altered host rocks in the absence of a rock buffer. Early chalcopyrite-bornite ± pyrite mineralization with potassic ± chloritic and sericitic alteration is only preserved on the margins of the system and more rarely at depth in a few holes 600 m bsl (~1,100 m below surface) but makes up only a small proportion (~8%) of the current resource. The Onto system is exceptionally young and formed rapidly in the middle Pleistocene and is not significantly eroded. A U-Pb zircon age for the andesite that caps the volcanosedimentary host rocks provides a maximum age of 0.838 ± 0.039 Ma, with a slightly younger porphyry zircon crystallization age of 0.688 ± 0.053 Ma. Re-Os dating of molybdenite that is associated with both the quartz vein stockwork and high-sulfidation assemblage copper mineralization shows overlap between 0.44 ± 0.02 and 0.35 ± 0.0011 Ma. 40Ar/39Ar ages for alunite within the advanced argillic alteration block ranges from 0.98 ± 0.22 to 0.284 ± 0.080 Ma, and alunite closely associated with covellite spans a period from 0.537 ± 0.064 to 0.038 ± 0.018 Ma.
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Gupta, Atul, Eric Snyder, Christiane Gottschalke, Kevin Wenzel, James Gunn, Hao Lu, Yuya Suzuki, Venky Sundaram, and Rao Tummala. "First Demonstration of Fine Line RDL Yield Enhancement using an Innovative Ozone Treatment Process for Panel Fan-out and Interposers." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2017, DPC (January 1, 2017): 1–19. http://dx.doi.org/10.4071/2017dpc-tp1_presentation2.
Full textAbstract:
As front end transistor scaling by Moore's law faces economic and technical challenges, interconnect scaling by advanced packaging technologies has started to add value at system level for a variety of electronics applications including consumer, high performance computing and automotive. The focus on yield improvement at every node that has enabled transistor scaling is now becoming a very critical need for high volume manufacturing of advanced packaging technologies such as 2.5D interposers and high density fanout [1]. This paper describes the first demonstration of a novel atmospheric approach based on ozone as an alternative to vacuum-based plasma treatment for photoresist cleaning to enhance the re-distribution layer (RDL) yields in advanced semi-additive process (SAP) processes. The ozone process is applicable to wafers as well as large panels, and is suited for small feature sizes down to 1um that are required for interposers and future fan-out packages. Ozone process provides an environmentally friendly solution eliminating the need for hazardous chemicals used in wet cleaning processes and has the potential to significantly increase throughput and reduce process cost compared to plasma processing by eliminating the need for vacuum chambers. The goal of this research is to demonstrate the effectiveness and benefits of the atmospheric dry ozone process developed using an MKS Instruments ozone delivery system for electrolytic copper plating yield improvement and dry film resist (DFR) residue cleaning, for 1-10um RDL critical dimensions (CD). The paper will describe the process fundamentals and the manufacturing tools, and discuss the characterization by contact angle measurements to confirm wettability of the plating surfaces, as well as demonstrate improvement of fine line RDL plating quality. The ever-increasing requirement for higher computing power in both high power applications and low power hand held or wearable devices is driving the need for higher signal bandwidth connections between logic and memory chips enabled through advances in the packaging world. The wiring density and I/O pitch are scaled down to achieve high bandwidth interconnections on a package with limited routing space. Photolithography, electrolytic copper plating, and copper seed layer etch are three crucial defining the yield and minimum feature size of RDL in the SAP flow. With the feature size scaling down to 3 μm, the quality of the metallized copper structure is crucial for high performance applications. Traditionally, wet chemical cleans are used for improving copper plating yields. The wet chemical process uses hazardous chemicals such as trichloroethylene (TCE) that are not environmentally friendly. These processes may be substituted with an oxygen plasma treatment that can clean organic residues in DFR trenches and improve wettability of the seed layers prior to plating as well as DFR residues after copper plating and DFR stripping. However, such plasma treatment approach requires a vacuum chamber which limits its throughput and cost effectiveness for high volume manufacturing. This paper proposes a higher throughput alternative solution to the plasma treatment process for electrolytic copper plating. Since the ozone gas is generated from oxygen, and reduced to oxygen upon process completion, no hazardous gas is required, or discharged into the atmosphere. To demonstrate the applicability of the ozone treatment to wafer-scale and panel-scale processing, two different types of copper seed layers, physical vapor deposition (PVD) Ti-Cu, and electroless plated copper, were evaluated. The effectiveness of both ozone and oxygen plasma treatments were qualified against a control sample with no treatment. The 7 μm thick DFR was laminated on the copper seed layers, then patterned with a projection lithography tool, and a minimum feature size of 3 μm was resolved. After photolithography, the substrates were subjected to ozone or plasma treatments. The water contact angle measurements show significant wettability improvement on the surfaces of substrates with copper seed layer, DFR, and DFR mesh patterned on a copper seed layer. Copper plating quality was then compared between samples. Both the ozone and plasma treatments resulted in excellent copper metallization quality due to the creation of a hydrophilic surface. The effectiveness of the ozone treatment at 50 deg C was confirmed, thus minimizing any impact on DFR stripping. The ozone treatment was also applied to clean the DFR residues after resist stripping and our results confirmed that the ozone process removed any remaining photoresist residues from the copper surface. In conclusion, this paper proposed and demonstrated high throughput, atmospheric pressure ozone treatment as an innovative alternative to plasma treatment for cleaning the surfaces prior to electrolytic copper plating, as well as for photoresist residue removal after resist strip. The results show yield improvement of plated RDL and DFR residue cleaning. The ozone process does not use any hazardous chemicals or gases and also does not require any vacuum steps, which makes it environmental friendly and high throughput, and offers a promising approach for fine line RDL for interposers and fan-out packages in meeting the semiconductor industry roadmap needs.
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Makkonen, Hannu V., and Pekka Tuisku. "Geology and crystallization conditions of the Särkiniemiintrusion and related nickel-copper ore, central Finland – implications for depth of emplacement of 1.88 Ga nickel-bearing intrusions." Bulletin of the Geological Society of Finland 92, no. 2 (December 15, 2020): 111–30. http://dx.doi.org/10.17741/bgsf/92.2.003.
Full textAbstract:
Several Ni-Cu deposits occur within the Kotalahti area, central Finland, in proximity to an Archaean gneiss dome surrounded by a Palaeoproterozoic craton-margin supracrustal sequence comprising quartzites, limestones, calc-silicate rocks, black schists and banded diopside amphibolites. The geology of the area and age of the Ni-bearing intrusions (1.88 Ga) are similar to the Thompson Ni belt in the Canadian Trans-Hudson Orogen. The small mafic-ultramafic and Ni-Cu -bearing Särkiniemi intrusion, closely associated with the Archaean basement core of the Kotalahti Dome, is composed of a western peridotite and eastern gabbro body, both of which are mineralized. The eastern gabbro has a contact aureole several meters thick, consisting of orthopyroxene +/- cordierite bearing hornfels between the intrusion and the migmatites. Geochemically, the Särkiniemi intrusion shares many features in common with other Svecofennian mafic-ultramafic intrusions, including crustal contamination and nickel depletion. The related Ni-Cu deposit has a low Ni/Co value (15) and low nickel content in the sulphide fraction (2.8 wt.%), together with a low estimated magma/sulphide ratio of around 170. Svecofennian 1.88 Ga mafic-ultramafic intrusions occur in terrains of variable metamorphic grade (from low-amphibolite to granulite facies) and are likely to represent emplacement at different crustal depths. Multi-equilibrium thermobarometry indicates that the contact aureole at Särkiniemi reached equilibrium at pressures of 4.5–6 kbar (15–20 km depth) and temperatures of 600–670 °C. Combined with the results of earlier research on the Svecofennian intrusions, this study indicates that a depth of 15–20 km crustal level was favourable, along with other critical factors, for nickel sulfide deposition at 1.88 Ga.