2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)最新文献
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463326
P. Altieri-Weimar, W. Yuan, E. S. Annibale, S. Schoemaker, D. Amberger, M. Goken, H. W. Hoppel
In this study the mechanical properties and fatigue behavior of ultra-fine gold wires are investigated by experimental tension fatigue tests and finite element (FE) simulation. Hardening behavior, yield criterion and yield surface of gold wire are determined by tensile tests and force controlled tension fatigue tests. The relationship between plastic strain and loading stress amplitude is determined and the cyclic strain hardening coefficient is calculated. The fatigue data are used to develop a predictive crack model for gold wires bonded in LED packages, based on finite element (FE) stress simulation at temperature cycles (TC). The computer model of the gold wire in the LED package used in the simulation is reconstructed from computer tomography (CT) analysis. The predictive crack model is calibrated using on-line monitoring of LED wire cracks during TC tests. Finally, using the reliability model, the impact of LED package design and material on the wire lifetime is investigated.
{"title":"Reliability model of LED package regarding the fatigue behavior of gold wires","authors":"P. Altieri-Weimar, W. Yuan, E. S. Annibale, S. Schoemaker, D. Amberger, M. Goken, H. W. Hoppel","doi":"10.1109/EUROSIME.2016.7463326","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463326","url":null,"abstract":"In this study the mechanical properties and fatigue behavior of ultra-fine gold wires are investigated by experimental tension fatigue tests and finite element (FE) simulation. Hardening behavior, yield criterion and yield surface of gold wire are determined by tensile tests and force controlled tension fatigue tests. The relationship between plastic strain and loading stress amplitude is determined and the cyclic strain hardening coefficient is calculated. The fatigue data are used to develop a predictive crack model for gold wires bonded in LED packages, based on finite element (FE) stress simulation at temperature cycles (TC). The computer model of the gold wire in the LED package used in the simulation is reconstructed from computer tomography (CT) analysis. The predictive crack model is calibrated using on-line monitoring of LED wire cracks during TC tests. Finally, using the reliability model, the impact of LED package design and material on the wire lifetime is investigated.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132572772","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463296
E. Monier-Vinard, B. Rogié, V. Bissuel, N. Laraqi, O. Daniel, Marie-Cécile Kotelon
Latest Computational Fluid Dynamic tools allow modelling more finely the conjugate thermo-fluidic behaviour of a single electronic component mounted on a Printed Wiring Board. A realistic three-dimensional representation of a large set of electric copper traces of its composite structure is henceforth achievable. So it is possible to confront the predictions of the fully detailed numerical model of an electronic board to a set of experiment results in order to assess their relevance. The present work shows that the numerical model error is lower than 2% for various boundary conditions. Moreover the practical modelling assumptions, such as effective thermal conductivity calculation, used since decades, for characterizing the thermal performances of an electronic component were checked and appeared to be very tricky. New approaches must be developed. Further the establishment of a realistic numerical model of electronic components permits to properly apprehend multi-physics design issues.
{"title":"State of the art of numerical thermal characterization of electronic component","authors":"E. Monier-Vinard, B. Rogié, V. Bissuel, N. Laraqi, O. Daniel, Marie-Cécile Kotelon","doi":"10.1109/EUROSIME.2016.7463296","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463296","url":null,"abstract":"Latest Computational Fluid Dynamic tools allow modelling more finely the conjugate thermo-fluidic behaviour of a single electronic component mounted on a Printed Wiring Board. A realistic three-dimensional representation of a large set of electric copper traces of its composite structure is henceforth achievable. So it is possible to confront the predictions of the fully detailed numerical model of an electronic board to a set of experiment results in order to assess their relevance. The present work shows that the numerical model error is lower than 2% for various boundary conditions. Moreover the practical modelling assumptions, such as effective thermal conductivity calculation, used since decades, for characterizing the thermal performances of an electronic component were checked and appeared to be very tricky. New approaches must be developed. Further the establishment of a realistic numerical model of electronic components permits to properly apprehend multi-physics design issues.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114057059","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463375
N. Barth, S. Ahzi, Zaid S. Al Otaibi
An uncoupled thermal and thermo-mechanical modeling of a solar panel is presented. The thermal modeling itself has been previously developed to assess the nominal performance of photovoltaic panels under various service conditions. Within this computational tool, assessing temperatures makes it also possible to analyze the thermal stresses. To study and predict the long-term reliability of the solar panel materials, the thermal cycling due to varying atmospheric conditions is then of particular interest. We undertake such multi-physics approach by taking into account the thermal cycling at the front side of the photovoltaic device packaging, including the solar cells, their antireflective coating, a glass layer and an eventual encapsulating polymer. Even within a simplified modeled design and an elastic constitutive behavior, we can evaluate the threshold to fatigue for most of these materials.
{"title":"Towards thermal fatigue modeling of photovoltaic panels under the gulf region harsh atmospheric conditions","authors":"N. Barth, S. Ahzi, Zaid S. Al Otaibi","doi":"10.1109/EUROSIME.2016.7463375","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463375","url":null,"abstract":"An uncoupled thermal and thermo-mechanical modeling of a solar panel is presented. The thermal modeling itself has been previously developed to assess the nominal performance of photovoltaic panels under various service conditions. Within this computational tool, assessing temperatures makes it also possible to analyze the thermal stresses. To study and predict the long-term reliability of the solar panel materials, the thermal cycling due to varying atmospheric conditions is then of particular interest. We undertake such multi-physics approach by taking into account the thermal cycling at the front side of the photovoltaic device packaging, including the solar cells, their antireflective coating, a glass layer and an eventual encapsulating polymer. Even within a simplified modeled design and an elastic constitutive behavior, we can evaluate the threshold to fatigue for most of these materials.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114784097","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463363
A. Mazloum-Nejadari, G. Khatibi, B. Czerny, M. Lederer, J. Nicolics, L. Weiss
In this study the thermo-mechanical response of 25 μm Cu wire bonds in an LQFP-EPad package was investigated by numerical and experimental means. The aim was to develop a methodology for fast evaluation of the packages, with focus on wire bond fatigue, by combining FEA and mechanical fatigue testing. The investigations included the following steps: (i) simulation of the warpage induced displacements in the encapsulated LQFP-176-Epad package due to temperature changes, (ii) reproducing the thermally induced stresses in the wire bond loops in an unmolded (non-encapsulated) LQFP package using an accelerated multiaxial mechanical fatigue testing set-up under the displacement amplitudes determined in case (i) and determination of the loading cycles to failure (Nf), (iii) FEA of the experiments performed in (ii) based on the boundary conditions determined in (i) to calculate the states of stress and strain in the wire bonds subjected to multiaxial mechanical cyclic loading. Our investigations confirm that thermal and mechanical cyclic loading results in occurrence of high plastic strains at the heat affected zone (HAZ) above the nail-head, which may lead to fatigue failure of the wire bonds in the packages. The lifetime of wire bonds show a proportional relation between the location and angle of the wire bond to the direction of loading. The calculated accumulated plastic strain in the HAZ was correlated to the experimentally determined Nf values based on the volume weighted averaging (VWA) approach and presented in a lifetime diagram (Δd - Nf) for reliability assessment of Cu wire bonds. The described accelerated test method could be used as a rapid qualification test for the determination of the lifetimes of wire bonds at different positions on the chip as well as for related improvements of package design.
{"title":"Reliability analysis of Cu wire bonds in microelectronic packages","authors":"A. Mazloum-Nejadari, G. Khatibi, B. Czerny, M. Lederer, J. Nicolics, L. Weiss","doi":"10.1109/EUROSIME.2016.7463363","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463363","url":null,"abstract":"In this study the thermo-mechanical response of 25 μm Cu wire bonds in an LQFP-EPad package was investigated by numerical and experimental means. The aim was to develop a methodology for fast evaluation of the packages, with focus on wire bond fatigue, by combining FEA and mechanical fatigue testing. The investigations included the following steps: (i) simulation of the warpage induced displacements in the encapsulated LQFP-176-Epad package due to temperature changes, (ii) reproducing the thermally induced stresses in the wire bond loops in an unmolded (non-encapsulated) LQFP package using an accelerated multiaxial mechanical fatigue testing set-up under the displacement amplitudes determined in case (i) and determination of the loading cycles to failure (Nf), (iii) FEA of the experiments performed in (ii) based on the boundary conditions determined in (i) to calculate the states of stress and strain in the wire bonds subjected to multiaxial mechanical cyclic loading. Our investigations confirm that thermal and mechanical cyclic loading results in occurrence of high plastic strains at the heat affected zone (HAZ) above the nail-head, which may lead to fatigue failure of the wire bonds in the packages. The lifetime of wire bonds show a proportional relation between the location and angle of the wire bond to the direction of loading. The calculated accumulated plastic strain in the HAZ was correlated to the experimentally determined Nf values based on the volume weighted averaging (VWA) approach and presented in a lifetime diagram (Δd - Nf) for reliability assessment of Cu wire bonds. The described accelerated test method could be used as a rapid qualification test for the determination of the lifetimes of wire bonds at different positions on the chip as well as for related improvements of package design.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116268059","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463313
R. Chassagne, Fabian Dorfler, M. Guyenot
The requirements for next-generation power electronic modules and devices imply enhanced energy densities, i.e., interconnection packaging technologies have to guarantee enhanced ampacity and robustness with respect to thermo-mechanical loads. Particularly, the interconnection layers of semi-conductor devices (e.g. MOSFET, IGBT, diodes) play a predominant role in the robustness of power electronic modules. Diffusion soldering (aka "HotPowCon", HPC) is a promising alternative with respect to the above mentioned requirements. HPC consists in the infiltration of a solder alloy melt into a porous copper matrix. The resulting intermetallic phases between copper and the soldering alloy have a melting point high above the standard processing and operating temperatures, and hence, a thermo-mechanically stable interconnection layer is formed. A simulation of this infiltration process requires the modeling of wetting dynamics in complex porous structures for which classical computational fluid dynamics (CFD) is limited with respect to computational efficiency. In contrast, the so-called lattice Boltzmann method (LBM), which is an indirect solver of the Navier-Stokes equations based on statistical physics, is numerically far more efficient. In this article, we present a simulation approach based on the LBM in order to model the response of infiltration rates on crucial HPC process parameters like viscosity and wettability of the liquid solder alloy, as well as porosity and geometrical properties of the copper matrix. The simulation results show consistency with the analytic Lucas-Washburn law for capillarity-driven flows in porous media. This can be seen as a proof of concept for the application of the LBM on the HPC infiltration process, and thus, the LBM might be the key-component of a future tool-chain for infiltration process optimization with respect to large-scale production demands.
{"title":"Modeling of the HPC infiltration process by means of the lattice Boltzmann method","authors":"R. Chassagne, Fabian Dorfler, M. Guyenot","doi":"10.1109/EUROSIME.2016.7463313","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463313","url":null,"abstract":"The requirements for next-generation power electronic modules and devices imply enhanced energy densities, i.e., interconnection packaging technologies have to guarantee enhanced ampacity and robustness with respect to thermo-mechanical loads. Particularly, the interconnection layers of semi-conductor devices (e.g. MOSFET, IGBT, diodes) play a predominant role in the robustness of power electronic modules. Diffusion soldering (aka \"HotPowCon\", HPC) is a promising alternative with respect to the above mentioned requirements. HPC consists in the infiltration of a solder alloy melt into a porous copper matrix. The resulting intermetallic phases between copper and the soldering alloy have a melting point high above the standard processing and operating temperatures, and hence, a thermo-mechanically stable interconnection layer is formed. A simulation of this infiltration process requires the modeling of wetting dynamics in complex porous structures for which classical computational fluid dynamics (CFD) is limited with respect to computational efficiency. In contrast, the so-called lattice Boltzmann method (LBM), which is an indirect solver of the Navier-Stokes equations based on statistical physics, is numerically far more efficient. In this article, we present a simulation approach based on the LBM in order to model the response of infiltration rates on crucial HPC process parameters like viscosity and wettability of the liquid solder alloy, as well as porosity and geometrical properties of the copper matrix. The simulation results show consistency with the analytic Lucas-Washburn law for capillarity-driven flows in porous media. This can be seen as a proof of concept for the application of the LBM on the HPC infiltration process, and thus, the LBM might be the key-component of a future tool-chain for infiltration process optimization with respect to large-scale production demands.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114950132","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463335
Zakriya Mohammed, G. Dushaq, A. Chatterjee, M. Rasras
This paper demonstrates the design and simulation of a 2-axis capacitive accelerometer. The design utilizes a simple comb structure to detect capacitance change with a minimum gap spacing of 0.9 μm. By optimizing the design and anti-gap spacing, the device is designed to yield high capacitance change with the proof mass displacement. Initial simulation results show a displacement sensitivity of 0.02μm/g (g=9.8 m/s2) and a differential capacitance sensitivity (scale factor) of 68 fF/g. The sensitivity achieved is best among the devices of its range (± 5g) and dimensions (2×2mm2). This device is being fabricated by GlobalFoundries-Singapore.
{"title":"Bi-axial highly sensitive ±5g polysilicon based differential capacitive accelerometer","authors":"Zakriya Mohammed, G. Dushaq, A. Chatterjee, M. Rasras","doi":"10.1109/EUROSIME.2016.7463335","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463335","url":null,"abstract":"This paper demonstrates the design and simulation of a 2-axis capacitive accelerometer. The design utilizes a simple comb structure to detect capacitance change with a minimum gap spacing of 0.9 μm. By optimizing the design and anti-gap spacing, the device is designed to yield high capacitance change with the proof mass displacement. Initial simulation results show a displacement sensitivity of 0.02μm/g (g=9.8 m/s2) and a differential capacitance sensitivity (scale factor) of 68 fF/g. The sensitivity achieved is best among the devices of its range (± 5g) and dimensions (2×2mm2). This device is being fabricated by GlobalFoundries-Singapore.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121075391","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463321
Nikhil Govindaiah, M. Dressler, Martin Bittlingmaier, Uwe Zundel, A. Yadur
The new generation active safety control units has enhanced features like pedestrian detection, tunnel detection, night vision etc. These driver assistance functions support the driver by triggering warnings in critical driving situations. These devices mounted on the vehicles has to sustain these additional loads and harsh environmental conditions. Reliability of such devices are very critical to human safety, hence needs to be designed with a very critical development process. Various design iterations are to be evaluated and optimized with the help of advanced design practices and finite element analysis followed by rigorous measurement and testing. One of the most common and critical environment load comes from thermal loading which accounts for maximum number of failures of electronic devices in automotive application. With this objective a coupled thermal and thermo-mechanical simulation was carried out considering active temperature cycle loads on the device at system-level. As the thermomechanical fatigue of solder joints on the system level is more complex to predict than on the board level. We used a two-step submodel approach. In the first step the electronic device with BGA package was included in the global device, though the creep behavior of solder joints was omitted, by considering the populated PCB with all relevant components (i.e. capacitors, inductors, connector etc.) which influence the strain on the PCB during thermal loading conditions, it is observed that the tendency of strain over temperature is in very good agreement, leading to more realistic PCB strains to co-relate with the measurement data. In the second step the simulation of the solder joints fatigue was carried out with the help of the submodel. The submodel technique allowed to reduce the simulation model of a system to the electronic device model with a piece of the PCB underneath and at the same time maintain realistic PCB deformations and the realistic temperature field in the entire submodel during the temperature cycle. The warpage of the component in not soldered state was used to obtain the proper material properties as well as to account also for the form change (cry, smile) during thermal cycling. This shape change leads to additional loading on the solder balls. Additional, the warpage in the soldered state on free PCB and in the housing was measured and compared with simulation results. By combining FE simulation and measurements at the early stage of product development, it is possible to estimate the risk factor to meet the design specifications.
{"title":"To predict component reliability for active safety devices under automotive application","authors":"Nikhil Govindaiah, M. Dressler, Martin Bittlingmaier, Uwe Zundel, A. Yadur","doi":"10.1109/EUROSIME.2016.7463321","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463321","url":null,"abstract":"The new generation active safety control units has enhanced features like pedestrian detection, tunnel detection, night vision etc. These driver assistance functions support the driver by triggering warnings in critical driving situations. These devices mounted on the vehicles has to sustain these additional loads and harsh environmental conditions. Reliability of such devices are very critical to human safety, hence needs to be designed with a very critical development process. Various design iterations are to be evaluated and optimized with the help of advanced design practices and finite element analysis followed by rigorous measurement and testing. One of the most common and critical environment load comes from thermal loading which accounts for maximum number of failures of electronic devices in automotive application. With this objective a coupled thermal and thermo-mechanical simulation was carried out considering active temperature cycle loads on the device at system-level. As the thermomechanical fatigue of solder joints on the system level is more complex to predict than on the board level. We used a two-step submodel approach. In the first step the electronic device with BGA package was included in the global device, though the creep behavior of solder joints was omitted, by considering the populated PCB with all relevant components (i.e. capacitors, inductors, connector etc.) which influence the strain on the PCB during thermal loading conditions, it is observed that the tendency of strain over temperature is in very good agreement, leading to more realistic PCB strains to co-relate with the measurement data. In the second step the simulation of the solder joints fatigue was carried out with the help of the submodel. The submodel technique allowed to reduce the simulation model of a system to the electronic device model with a piece of the PCB underneath and at the same time maintain realistic PCB deformations and the realistic temperature field in the entire submodel during the temperature cycle. The warpage of the component in not soldered state was used to obtain the proper material properties as well as to account also for the form change (cry, smile) during thermal cycling. This shape change leads to additional loading on the solder balls. Additional, the warpage in the soldered state on free PCB and in the housing was measured and compared with simulation results. By combining FE simulation and measurements at the early stage of product development, it is possible to estimate the risk factor to meet the design specifications.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126465685","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463394
Bingbing Zhang, M. Johlitz, A. Lion, L. Ernst, K. Jansen, D. Vu, L. Weiss
It is well known that epoxy moulding compound (EMC) plays an important role in the reliability of electronic packages. In order to predict the mechanical behaviour of electronic packages that are encapsulated with moulding compound, the material properties of EMCs should be carefully characterized and modelled. Currently, more and more components are exposed to severe environments. Among these, high temperature conditions can lead to irreversible changes in EMCs. These changes can be attributed to chemical processes such as oxidation and can lead to degradation of the applied resins, which we refer to here as aging. As a result, the thermo-mechanical properties of the EMCs change severely with time. Due to ongoing changes in the aging EMC of a package, the stress and strain distributions in the package change with time, while embrittlement affects the fracture strength. As a consequence, the long-term reliability of a package is severely affected. Since an appropriate constitutive representation of the material properties of the slowly growing oxidation layers is not available, it is cumbersome to predict the reliability of real packages for long term applications. Being motivated by this limitation, in the present work, we focus on the experimental characterization as well as on the numerical modelling of aging of EMCs at high temperature storage (HTS). As a result the long term stress-strain distribution of a package can be simulated.
{"title":"Aging of epoxy moulding compound — Thermomechanical properties during high temperature storage","authors":"Bingbing Zhang, M. Johlitz, A. Lion, L. Ernst, K. Jansen, D. Vu, L. Weiss","doi":"10.1109/EUROSIME.2016.7463394","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463394","url":null,"abstract":"It is well known that epoxy moulding compound (EMC) plays an important role in the reliability of electronic packages. In order to predict the mechanical behaviour of electronic packages that are encapsulated with moulding compound, the material properties of EMCs should be carefully characterized and modelled. Currently, more and more components are exposed to severe environments. Among these, high temperature conditions can lead to irreversible changes in EMCs. These changes can be attributed to chemical processes such as oxidation and can lead to degradation of the applied resins, which we refer to here as aging. As a result, the thermo-mechanical properties of the EMCs change severely with time. Due to ongoing changes in the aging EMC of a package, the stress and strain distributions in the package change with time, while embrittlement affects the fracture strength. As a consequence, the long-term reliability of a package is severely affected. Since an appropriate constitutive representation of the material properties of the slowly growing oxidation layers is not available, it is cumbersome to predict the reliability of real packages for long term applications. Being motivated by this limitation, in the present work, we focus on the experimental characterization as well as on the numerical modelling of aging of EMCs at high temperature storage (HTS). As a result the long term stress-strain distribution of a package can be simulated.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125781570","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463294
J. Libot, L. Arnaud, O. Dalverny, J. Alexis, P. Milesi, F. Dulondel
Vibration-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free mechanical behavior under vibration conditions. This study reports the durability of Sn3.0Ag0.5Cu (SAC305) solder joints subjected to harmonic solicitations at three specific temperatures (-55°C, 20°C and 105°C) and random vibrations at ambient temperature (20°C). A test assembly was designed and consisted in a single daisy-chained 1152 I/O ball grid array (FBGA1152) package assembled on a flame retardant (FR-4) printed circuit board (PCB). The vibration levels were imposed by a controlled deflection at the center of the board at its natural frequency. The electric continuity was monitored to determine the number of cycles to failure of each sample. Mode shape measurements with a scanning vibrometer were also conducted and correlated with finite element analysis (FEA) to ensure accurate calculation of strain within the critical solder balls at the corners of the component. The failed specimens were then cross-sectioned in order to determine failure modes. A comparison of SAC305 durability with SnPb36Ag2 solder is given, along with a set of lifetime measurements for two complementary assemblies: 68 I/O Leadless Chip Carrier (LCC68) and 324 I/O Plastic Ball Grid Array (PBGA324). For the tested harmonic vibration levels, SAC305 outperforms SnPb36Ag2. Furthermore, the effect of temperature on the mechanical durability of SAC305 appears to be minor. Failure analysis pointed out different failure modes on PCB and component side, along with pad cratering and copper trace failures. FEA calculations allows the determination of the SAC305 fatigue curve to estimate the high cycle fatigue (HCF) behavior of SAC305 solder under harmonic vibrations. The random vibrations durability of SAC305 solder was assessed using the same test assembly (FBGA1152) which was subjected to three different levels of Power Spectral Density (PSD) at 20°C. The random vibrations tests were conducted within a frequency band ranging from 500 Hz to 900 Hz around the natural frequency. The chosen PSD levels applied were 0.04, 0.10 and 0.20 g2/Hz. Using power-law fitting, the results give a first estimation of the durability of SAC305 solder joints subjected to random vibrations.
{"title":"Mechanical fatigue assessment of SAC305 solder joints under harmonic and random vibrations","authors":"J. Libot, L. Arnaud, O. Dalverny, J. Alexis, P. Milesi, F. Dulondel","doi":"10.1109/EUROSIME.2016.7463294","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463294","url":null,"abstract":"Vibration-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free mechanical behavior under vibration conditions. This study reports the durability of Sn3.0Ag0.5Cu (SAC305) solder joints subjected to harmonic solicitations at three specific temperatures (-55°C, 20°C and 105°C) and random vibrations at ambient temperature (20°C). A test assembly was designed and consisted in a single daisy-chained 1152 I/O ball grid array (FBGA1152) package assembled on a flame retardant (FR-4) printed circuit board (PCB). The vibration levels were imposed by a controlled deflection at the center of the board at its natural frequency. The electric continuity was monitored to determine the number of cycles to failure of each sample. Mode shape measurements with a scanning vibrometer were also conducted and correlated with finite element analysis (FEA) to ensure accurate calculation of strain within the critical solder balls at the corners of the component. The failed specimens were then cross-sectioned in order to determine failure modes. A comparison of SAC305 durability with SnPb36Ag2 solder is given, along with a set of lifetime measurements for two complementary assemblies: 68 I/O Leadless Chip Carrier (LCC68) and 324 I/O Plastic Ball Grid Array (PBGA324). For the tested harmonic vibration levels, SAC305 outperforms SnPb36Ag2. Furthermore, the effect of temperature on the mechanical durability of SAC305 appears to be minor. Failure analysis pointed out different failure modes on PCB and component side, along with pad cratering and copper trace failures. FEA calculations allows the determination of the SAC305 fatigue curve to estimate the high cycle fatigue (HCF) behavior of SAC305 solder under harmonic vibrations. The random vibrations durability of SAC305 solder was assessed using the same test assembly (FBGA1152) which was subjected to three different levels of Power Spectral Density (PSD) at 20°C. The random vibrations tests were conducted within a frequency band ranging from 500 Hz to 900 Hz around the natural frequency. The chosen PSD levels applied were 0.04, 0.10 and 0.20 g2/Hz. Using power-law fitting, the results give a first estimation of the durability of SAC305 solder joints subjected to random vibrations.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129496914","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}
Pub Date : 2016-04-18DOI: 10.1109/EUROSIME.2016.7463340
P. Meszmer, K. Hiller, R. D. Rodriguez, E. Sheremet, D. Zahn, M. Hietschold, B. Wunderle
For the development of lifetime models in a physics-of-failure approach for microelectronic devices and functional elements on the submicron or even nanoscopic scale, the exact knowledge of the materials in use and their failure behavior is imperative. A piezoresistive MEMS force sensor, which can be integrated in MEMS sized tensile and fatigue test stages, was developed and is characterized using micro-Raman spectroscopy. This paper describes the experimental approach, the implementation and results of micro-Raman stress measurements in comparison to numerical simulations based on the finite element method.
{"title":"Raman based stress analysis of the active areas of a piezoresistive MEMS force sensor — Experimental setup, data processing, and comparison to numerically obtained results","authors":"P. Meszmer, K. Hiller, R. D. Rodriguez, E. Sheremet, D. Zahn, M. Hietschold, B. Wunderle","doi":"10.1109/EUROSIME.2016.7463340","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463340","url":null,"abstract":"For the development of lifetime models in a physics-of-failure approach for microelectronic devices and functional elements on the submicron or even nanoscopic scale, the exact knowledge of the materials in use and their failure behavior is imperative. A piezoresistive MEMS force sensor, which can be integrated in MEMS sized tensile and fatigue test stages, was developed and is characterized using micro-Raman spectroscopy. This paper describes the experimental approach, the implementation and results of micro-Raman stress measurements in comparison to numerical simulations based on the finite element method.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125054564","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}
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