2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)最新文献

{"title":"Thermo-mechanical simulations in double-sided heat transfer power assemblies","authors":"E. Woirgard, Isabelle Favre, J. Delétage, S. Azzopardi, Renan Léon, Guy Convenant, Zoubir Khatir","doi":"10.1109/ESIME.2010.5464614","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464614","url":null,"abstract":"In power assemblies, heat transfer due to the die self-heating is one of the most important point on time life assemblies. Heat has to be evacuated toward the base-plate not to weaken the solder joint under the die. Double-sided assemblies are attractive for heat transfer and many studies were initiated to have better heat transfer. So, we can observe less density energy deformation (DED) in solder joints and more stresses in the die. The purpose of this paper is to quantify the part of DED in the joint compared to the stresses in the die and finally to see the best configuration between single or double face assemblies.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122447804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermomechanical design and modeling of porous alumina-based thin film packages for MEMS","authors":"J. Zekry, B. Vandevelde, S. Bouwstra, R. Puers, C. van Hoof, H. Tilmans","doi":"10.1109/ESIME.2010.5464584","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464584","url":null,"abstract":"Thin film 0-level or wafer-level MEMS packages exhibit relatively low flexural strength and yet they are required to reliably protect the enclosed MEMS devices under extreme processing and operational conditions. In this paper, we present a thermomechanical study of porous alumina-based thin film MEMS packages by making use of finite element modeling (FEM) techniques. We developed a 2D axisymmetric FEM that includes a porosity-dependent orthotropic representation of the porous alumina layer. The results of the FEM for a typical thin film package show around 15% enhancement over an analytical circular plate model in terms of the accuracy of calculating the maximum cap deflection under 105Pa differential pressure. The simulated package performance illustrates the significance of several parameters such as the package geometry, external hydrostatic pressure, residual stresses in the thin film, and the ambient temperature. Simulations further show that a circular package of 180µm diameter, featuring an 8µm thick cap and a central supporting pillar of 20µm diameter can withstand hydrostatic pressures up to 9MPa, which could occur during the process of plastic packaging with an epoxy molding compound. Furthermore, the thermal expansion mismatch between the different materials composing the thin film package poses a challenge to fulfill the reliability characteristics of these packages. It is however possible, based on FEM simulation results, to achieve reliable operation in the temperature range between −55°C and +125°C for a circular package of 6µm cap thickness and 250µm diameter without a supporting pillar.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125119157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale viscoplastic modeling of Pb-free Sn3.0Ag0.5Cu solder interconnects","authors":"G. Cuddalorepatta, A. Dasgupta","doi":"10.1109/ESIME.2010.5464530","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464530","url":null,"abstract":"A mechanistic multiscale modeling framework is proposed, to capture the dominant creep mechanisms and the influence of key microstructural features on the measured secondary creep response of microscale asfabricated Sn3.0Ag0.5Cu (SAC305) solder interconnects. At the smallest length scale, mechanistic dislocation creep models are used to capture the creep strengthening mechanisms in the Sn-Ag eutectic phase. These models account for the strengthening from the microscale Cu6Sn5 intermetallics as well as the nanoscale dimension Ag3Sn intermetallic particles. At the next length scale, these models are combined to capture the load-sharing between Sn dendrites and intermetallic phases. The next higher length scale (Sn grains) is not addressed here since secondary creep response is empirically found to be insensitive to grain microstructure [1]. The model constants of the proposed framework are obtained from secondary creep measurements of SAC305 solder [1], using a modified lap-shear microscale solder specimen and a custom-built Thermo-Mechanical Microscale (TMM) test setup (Figure 1). The calibrated model is used to study the effect of alloy composition and aging loads on SAC solders, by accounting for the changes in the eutectic Sn-Ag region, IMCs and the Sn dendrites. The results show that the multi-scale model predictions provide the right qualitative trends, and, quantitatively match the SAC105 (Figure 2) and prior measurements from SAC387 [2–3] (not shown here) very well. The model also captures the degradation in the creep properties of as-fabricated SAC305 solder subject to isothermal aging (not shown here). The model effectively captures the effect of alloy composition and aging loads on SAC solders, thereby aiding in the effective design and optimization of the viscoplastic behavior of SAC alloys.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126351041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-speed mechanical impact reliability of solder interconnections in high-power LEDs","authors":"J. Hokka, J. Caers, X. Zhao, M. De Jong, W. Peels, B. Sykes, G. Zhang, M. Paulasto-Krockel","doi":"10.1109/ESIME.2010.5464562","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464562","url":null,"abstract":"Light Emitting Diodes (LED) are being implemented more and more into demanding applications like automotive and high-brightness general lighting. From the reliability point of view, the automotive environment is extremely harsh and challenging. Automotive electronics have to withstand exposure to high temperature fluctuations, mechanical shock impacts and vibration. The cyclic thermal load of solder interconnections can be up to 150°C for several thousand cycles. For harsh environments, high-Pb and eutectic AuSn solders are currently being used as the interconnection material. Recent developments of SAC-based solders provide alternative lead-free solutions with lower processing temperature. However, little is known about the reliability and failure mechanism of these solder interconnections, especially under mechanical impact loadings. For a successful reliability test of the solder interconnection under the impact, it is important to find a widely accepted mechanical test method of measuring the degradation of the interconnection. In this study a newly designed high-speed impact tester that is based on the use of a pendulum was used to achieve this target. The purpose was to investigate the mechanical behaviour of lead-free solder interconnections under different loading conditions. The studied carrier had multi dies mounted onto a ceramic sub-mount, which was soldered to a Cu substrate. In total 60 samples were tested with five different test velocities (0.7, 1.0, 1.4, 1.8 and 2.2 m/s). The test results showed that the primary failure mode was the ductile failure in the solder bulk and only some local fractures at the solder interfaces were observed. This indicates that there was no dependency of the test velocity, since all the test velocities induced similar failures in the bulk solder of the solder joints.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114664298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are current turbulence modeling practices addressing industry's needs for electronics thermal design?","authors":"P. Rodgers, V. Eveloy","doi":"10.1109/ESIME.2010.5464509","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464509","url":null,"abstract":"Since the 1990's, computational fluid dynamics (CFD) has been widely adopted in the electronics industry for the thermal design of electronic products. Its advantages in terms of product improvements and enhanced productivity of design analysis, are undisputed. However, the industry has also experienced that incorrect product design decisions can be taken as a result of inaccurate CFD predictions, with consequences ranging from reduced product performance and reliability, to catastrophic field failure. Consequently, understanding and minimizing CFD prediction errors is a major concern to ensure a return on capital, software and human resource investments in the thermal design process. Sources of CFD inaccuracy can be categorized as either (i) errors of a numerical (e.g., round-offs, convergence, discretization), coding-, or user nature, or (ii) uncertainties in model inputs (e.g., limited information or approximations in the representation of geometry, material properties, and boundary conditions such as fan flows and screen losses) and in physical models (e.g., representation of physical processes such as turbulence, simplifying assumptions such as steady-state analysis or adiabatic heat transfer boundary). Assuming that the CFD code is correct and that user errors are negligible, this Talk focuses on two unvoidable sources of CFD prediction errors, and candidate solutions to minimize them: (a) physical model uncertainties associated with current Reynolds-averaged Navier-Stokes (RANS) turbulence modeling, and (b) input uncertainties associated with boundary conditions such as fan flows. In relation to topic (a), an overview of the current state-of-the-art in CFD for electronics cooling applications is presented, as well as published CFD benchmarks relating to air- and liquid cooling applications. The challenges for improved predictive accuracy are outlined in the context of two opposing arguments relating to physical model uncertainties: (i) the development and optimization of turbulence models for limited categories of flows, versus (ii) the search for a comprehensive, general-purpose turbulent flow model. With respect to topic (b), the fact that detailed modeling inputs are generally not available during the design phase, may no longer justify the view that standard turbulence models applied on simple grids are satisfactory, offer efficient analysis and solution stability. This argument may become outdated with increases in computational power, which will facilitate the application of more sophisticated turbulence models to electronic system thermal design. To illustrate the difficulties typically encountered in the industry to predict heat transfer and fluid flow in electronic systems, a benchmark study of an air-cooled mock-up telecommunication unit is presented. The case study highlights substantial CFD prediction discrepandies with experimental measurements of temperature and fluid flow, which are found to be associated with uncertainties ","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114258058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The study of carbon nanotube's length in reference to its thermal conductivity by molecular dynamics approach","authors":"B. Platek, T. Falat, J. Felba, Artur Borzdun","doi":"10.1109/ESIME.2010.5464538","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464538","url":null,"abstract":"Current paper focuses on the influence of carbon nanotube (CNT) length on its thermal conductivity. The powerful technique which is molecular modeling was used. The non-equilibrium molecular dynamics was implemented in commercially available software. The eight single-walled carbon nanotubes from 50 nm to 400 nm was investigated. The obtained results show the trend of increasing thermal conductivity for longer nanotubes.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124096035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the residual shrinkage during lithographic processing on flexible polymer substrates","authors":"M. Barink, D. van den Berg, I. Yakimets, E. Meinders","doi":"10.1109/ESIME.2010.5464564","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464564","url":null,"abstract":"The challenge of lithographic production of electronic circuitry on polymer foil is that deformations approaching the feature sizes of the circuitry can cause considerable overlay problems and thereby malfunctioning of the devices. The substrate foil is susceptible to several types of deformations. Accurate prediction of these deformations is of great importance, as it will help to improve the production process and thereby improve the quality of the electronic devices. One of the deformations is the residual shrinkage, a deformation that occurs after application of a heat step to a polymer foil. This study presents an experimental investigation of residual shrinkage combined with a modeling approach in which the temperature dependent visco-elastic material properties of the foil are used. The model enables us to more accurately predict overlay errors.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"95 14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129137917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring time-dependent mechanics in metallic MEMS","authors":"L. Bergers, N. Delhey, J. Hoefnagels, M. Geers","doi":"10.1109/ESIME.2010.5464590","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464590","url":null,"abstract":"The reliability of metallic microelectromechanical systems (MEMS) depends on time-dependent deformation such as creep. The interaction between microstructural length scales and dimensional length scales, so-called ‘size-effects’, play a prominent role in this. As a first critical step towards studying these size effects in time-dependent deformation, a purely mechanical experimental methodology has been developed, which is discussed here. It is found most suitable for the investigation of creep due to the simplicity of sample handling and preparation and setup design, whilst maximizing long term stability and displacement resolution. The methodology entails the application of a constant deflection to a µm-sized free-standing aluminum cantilever beam for a prolonged period of time. After this load is removed, the deformation evolution is immediately recorded by acquiring surface height profiles through confocal optical profilometry. Image correlation and an algorithm based on elastic beam theory are applied to the full-field beam profiles to yield the tip deflection as function of time. From a discussion on the sources of experimental error, it is concluded that the methodology yields the tip deflection as function of time with ∼3 nm precision.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114717109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electromigration modeling with consideration of hillock formation","authors":"Y. Zhang, L. Liang, Y. Liu","doi":"10.1109/ESIME.2010.5464568","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464568","url":null,"abstract":"This paper investigates the electromigration induced hillock generation in a wafer level interconnect structure through numerical approach. The electronic migration formulation that considers the effects of the electron wind force, stress gradients, temperature gradients, as well as the atomic density gradient has been developed. The parameter study for the Al line geometry with different width and thickness of a SWEAT structure is investigated. The comparison of void/hillock formation and the time to failure (TTF) life through numerical example of the SWEAT structure with the measurement result are studied and discussed. Finally, the TTF life of a hillock is defined and discussed.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133048396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the geometrical dimensions on stress and strain of electrostatically actuated MEMS resonators at pull-in and stiction positions","authors":"M. Pustan, V. Rochus, J. Golinval","doi":"10.1109/ESIME.2010.5464576","DOIUrl":"https://doi.org/10.1109/ESIME.2010.5464576","url":null,"abstract":"The aims of this study are to estimate the effect of geometrical dimensions on stiffness, stress and strain of flexible MEMS structures at pull-in and stiction positions. Microcantilevers and microbridges are often used as flexible mechanical elements in microsystems for sensing and actuation functions. Analytical models for stiffness, stress and strain of flexible microcomponents as microcantilevers are developed and presented in this paper. Experimental investigations are performed on samples fabricated from gold with different geometrical dimensions using Atomic Force Microscope. The distribution of stress in deformable MEMS components is changed as function of the contact areas between the flexible plate and substrate.","PeriodicalId":152004,"journal":{"name":"2010 11th International Thermal, Mechanical & Multi-Physics Simulation, and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133372161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}