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.2016.7463367
G. Capeans, P. López, E. Ferro, A. Garcia Loureiro, D. Cabello, F. Rivadulla, B. Rivas‐Murias
Coupled simulations of both thermal and electrical processes are employed to perform reliable estimations of the harvesting capabilities of a novel thermoelectric generator concept based on the use of p- and n-type materials films of nanometric thickness separated by a dielectric layer. The doping and geometrical parameters of the device are optimized to maximize the thermoelectrical properties while guaranteeing optimal power transfer efficiency with the use of mixed mode simulations in conventional CAD tools.
{"title":"Design for maximum power transfer efficiency of thermoelectric generators using mixed mode simulations","authors":"G. Capeans, P. López, E. Ferro, A. Garcia Loureiro, D. Cabello, F. Rivadulla, B. Rivas‐Murias","doi":"10.1109/EUROSIME.2016.7463367","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463367","url":null,"abstract":"Coupled simulations of both thermal and electrical processes are employed to perform reliable estimations of the harvesting capabilities of a novel thermoelectric generator concept based on the use of p- and n-type materials films of nanometric thickness separated by a dielectric layer. The doping and geometrical parameters of the device are optimized to maximize the thermoelectrical properties while guaranteeing optimal power transfer efficiency with the use of mixed mode simulations in conventional CAD tools.","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":"128932853","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.2016.7463384
F. Schindler-Saefkow, R. Pantou, G. Schlottig, Sridhar Kumar, T. Brunschwiler, J. Keller, B. Wunderle, S. Rzepka
Finite Element Simulations of highly integrated and large electronics packages with detailed elastic-plastic material modeling of thousands of solder balls are still challenging tasks for today's computation systems. The complex geometry and mesh and the usage of time consuming creep laws for solder materials makes it nearly impossible to calculate different geometries or process parameters. This paper describes a method to reduce the complexity of the mesh in the region of the solder balls and surrounding underfill with one simple block physically described as a viscoelastic material. Therefore a viscoelastic/plastic behavior of a complex unit cell was modeled in a temperature dependent harmonic frequency sweep or relaxation simulation. The reaction of the unit cell was utilized to synthesize the master curve, Prony coefficients and shift function to an effective material model. Finally an error estimation of the unit cell approach was carried out. Therefore a reliability simulation was modeled replacing the solder balls and the surrounding underfill by the effective material. A flip chip on FR4 model with underfill was used to benchmark the effective material model approach against detailed models without any complexity reduction. The results show that the introduced effective material approach can be used to cut down computation time significantly without losing accuracy in life time prediction.
{"title":"Master curve synthesis by effective viscoelastic plastic material modeling","authors":"F. Schindler-Saefkow, R. Pantou, G. Schlottig, Sridhar Kumar, T. Brunschwiler, J. Keller, B. Wunderle, S. Rzepka","doi":"10.1109/EUROSIME.2016.7463384","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463384","url":null,"abstract":"Finite Element Simulations of highly integrated and large electronics packages with detailed elastic-plastic material modeling of thousands of solder balls are still challenging tasks for today's computation systems. The complex geometry and mesh and the usage of time consuming creep laws for solder materials makes it nearly impossible to calculate different geometries or process parameters. This paper describes a method to reduce the complexity of the mesh in the region of the solder balls and surrounding underfill with one simple block physically described as a viscoelastic material. Therefore a viscoelastic/plastic behavior of a complex unit cell was modeled in a temperature dependent harmonic frequency sweep or relaxation simulation. The reaction of the unit cell was utilized to synthesize the master curve, Prony coefficients and shift function to an effective material model. Finally an error estimation of the unit cell approach was carried out. Therefore a reliability simulation was modeled replacing the solder balls and the surrounding underfill by the effective material. A flip chip on FR4 model with underfill was used to benchmark the effective material model approach against detailed models without any complexity reduction. The results show that the introduced effective material approach can be used to cut down computation time significantly without losing accuracy in life time prediction.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"27 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":"128992452","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.2016.7463332
T. Onken, J. Heilmann, T. Bieniek, R. Pufall, B. Wunderle
Aluminium is still one of the most important contact metallisations for power electronic chips like MOSFETs or IGBTs. With a large difference in thermal expansion coefficients (CTEs) between aluminium and silicon and the temperatures generated in hot-spots during high power transients, these layers are prone to failure due to thermo-mechanical fatigue. So far, lifetime modelling was done by subjecting dedicated test specimens to the thermal cycling one would expect during normal operation. This paper will propose a novel method for creating accelerated lifetime models of thin aluminium films within the high-cycle fatigue regime by isothermal mechanical loads. The specially designed test stand is suggested to complement or replace expensive and lengthy thermal cycling and allow in-situ monitoring of failure indicators.
{"title":"High cycle fatigue testing and modelling of sputtered aluminium thin films on vibrating silicon MEMS cantilevers","authors":"T. Onken, J. Heilmann, T. Bieniek, R. Pufall, B. Wunderle","doi":"10.1109/EUROSIME.2016.7463332","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463332","url":null,"abstract":"Aluminium is still one of the most important contact metallisations for power electronic chips like MOSFETs or IGBTs. With a large difference in thermal expansion coefficients (CTEs) between aluminium and silicon and the temperatures generated in hot-spots during high power transients, these layers are prone to failure due to thermo-mechanical fatigue. So far, lifetime modelling was done by subjecting dedicated test specimens to the thermal cycling one would expect during normal operation. This paper will propose a novel method for creating accelerated lifetime models of thin aluminium films within the high-cycle fatigue regime by isothermal mechanical loads. The specially designed test stand is suggested to complement or replace expensive and lengthy thermal cycling and allow in-situ monitoring of failure indicators.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"17 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":"128411953","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.2016.7463373
M. Springer, M. Nelhiebel, H. Pettermann
Power semiconductors may be subjected to short electric overload pulses during operation, which induce very high temperatures and temperature gradients in the multilayer chip structure. This can lead to material degradation in the ductile metallization and repetitive overload conditions can result in overheating and destruction of the device. A unified approach is presented predicting material degradation in terms of fatigue crack nucleation and fatigue crack propagation, to identify a tolerable number of electric overload pules during operation. Fatigue Indicators based on mechanical quantities are utilized to identify locations of material failure in the power metallization and material degradation is modeled. Repetitive loading leads to an evolving damage zone. The proposed approach is implemented within the framework of the Finite Element Method and exemplified at a simplified, generic metallization stack.
{"title":"Fatigue crack growth modeling in the metallization of power semiconductors under cyclic thermo-mechanical loading","authors":"M. Springer, M. Nelhiebel, H. Pettermann","doi":"10.1109/EUROSIME.2016.7463373","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463373","url":null,"abstract":"Power semiconductors may be subjected to short electric overload pulses during operation, which induce very high temperatures and temperature gradients in the multilayer chip structure. This can lead to material degradation in the ductile metallization and repetitive overload conditions can result in overheating and destruction of the device. A unified approach is presented predicting material degradation in terms of fatigue crack nucleation and fatigue crack propagation, to identify a tolerable number of electric overload pules during operation. Fatigue Indicators based on mechanical quantities are utilized to identify locations of material failure in the power metallization and material degradation is modeled. Repetitive loading leads to an evolving damage zone. The proposed approach is implemented within the framework of the Finite Element Method and exemplified at a simplified, generic metallization stack.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"365 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":"116321535","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.2016.7463392
A. Halbach, C. Geuzaine
This paper describes a method to automatically derive multiharmonic finite element formulations for coupled, nonlinear electromechanical problems. It focuses on models of electrically actuated micromembranes using both a staggered and a monolithic Newton iteration scheme. Two- and three-dimensional examples highlight the main properties of the proposed method.
{"title":"Automatic derivation of multiharmonic formulations for nonlinear electromechanical problems with time dependent mesh deformation","authors":"A. Halbach, C. Geuzaine","doi":"10.1109/EUROSIME.2016.7463392","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463392","url":null,"abstract":"This paper describes a method to automatically derive multiharmonic finite element formulations for coupled, nonlinear electromechanical problems. It focuses on models of electrically actuated micromembranes using both a staggered and a monolithic Newton iteration scheme. Two- and three-dimensional examples highlight the main properties of the proposed method.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"21 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":"115423498","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.2016.7463338
A. Salahouelhadj, M. Gonzalez
Thermo-mechanical stresses are often induced during processing of IC-packages. This is mainly due the Coefficient of Thermal Expansion (CTE) mismatch between the materials used to make these packages. Therefore, accurate CTE measurements is of great importance. In this study in-plane CTE measurements were conducted for thin film samples using Digital Image Correlation (DIC). The methodology was validated using copper test samples. Two different package substrates were characterized. DIC technique was compared to Thermal Mechanical Analysis (TMA) technique. The CTE measured by DIC is about 25-33% higher than TMA. Finally, some experimental and numerical tests were conducted to assess errors related to DIC technique. Both numerical and experimental tests, based on rigid-body motion were conducted. They allow to assess the errors related to lighting, the optical lens distortion, the noise due to CCD sensor and heat radiation, the out-of-plane displacement and the correlation algorithm.
{"title":"CTE measurements for 3D package substrates using Digital Image Correlation","authors":"A. Salahouelhadj, M. Gonzalez","doi":"10.1109/EUROSIME.2016.7463338","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463338","url":null,"abstract":"Thermo-mechanical stresses are often induced during processing of IC-packages. This is mainly due the Coefficient of Thermal Expansion (CTE) mismatch between the materials used to make these packages. Therefore, accurate CTE measurements is of great importance. In this study in-plane CTE measurements were conducted for thin film samples using Digital Image Correlation (DIC). The methodology was validated using copper test samples. Two different package substrates were characterized. DIC technique was compared to Thermal Mechanical Analysis (TMA) technique. The CTE measured by DIC is about 25-33% higher than TMA. Finally, some experimental and numerical tests were conducted to assess errors related to DIC technique. Both numerical and experimental tests, based on rigid-body motion were conducted. They allow to assess the errors related to lighting, the optical lens distortion, the noise due to CCD sensor and heat radiation, the out-of-plane displacement and the correlation algorithm.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"19 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":"116249017","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.2016.7463316
S. Gallois-Garreignot, V. Fiori, Gil Provent, R. Gonella
WLCSP (Wafer Level Chip Scale Packaging) is used to enable low-cost manufacturing and a high performance featuring low I/O density. Such a solution provides a solder interconnection directly between the die and motherboard. This paper aims at presenting the specificities of this new assembly by describing the most common thermo-mechanical failures encountered and by proposing some containment solutions and ways of improvement. Despite its advantages, this solution raises particular thermo-mechanical failures. Cracking of passivation or under layers, humidity penetration and/or delamination from the die edge are some of the main issues generally observed. Moreover, we need to pay extra attention to the die edge since this region is particularly sensitive. Indeed, for Fan-In configuration, the die is exposed to the atmosphere (no molding compound surrounding the die), leading to chemical contamination and cracks. Numerous causes are involved: e.g. non-optimized sawing process and weakness of the seal ring structure (i.e. metal pattern surrounding the die and providing mechanical and chemical shields). Furthermore, due to the bump and passivation layer proximities, some interactions may exist with the BEoL stack itself. FEM (Finite Element Method) is carried out, with a particular focus on the Fan-In package. Typical stress fields are provided, giving clues on WLCSP package specificities to mitigate mechanical hazard. Then, following the previously depicted failures, both the die and the passivation edges are comprehensively studied. It is shown that a stress peak is induced by the passivation edge, providing requirements on the deposit strategy (direct or pyramidal) and the edge location. Additionally, it is shown that the residual stress and the thickness of the BEoL passivation layer have also to be reduced and increased respectively.
{"title":"Wafer Level Chip Scale Packaging: Thermo-mechanical failure modes, challenges & guidelines","authors":"S. Gallois-Garreignot, V. Fiori, Gil Provent, R. Gonella","doi":"10.1109/EUROSIME.2016.7463316","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463316","url":null,"abstract":"WLCSP (Wafer Level Chip Scale Packaging) is used to enable low-cost manufacturing and a high performance featuring low I/O density. Such a solution provides a solder interconnection directly between the die and motherboard. This paper aims at presenting the specificities of this new assembly by describing the most common thermo-mechanical failures encountered and by proposing some containment solutions and ways of improvement. Despite its advantages, this solution raises particular thermo-mechanical failures. Cracking of passivation or under layers, humidity penetration and/or delamination from the die edge are some of the main issues generally observed. Moreover, we need to pay extra attention to the die edge since this region is particularly sensitive. Indeed, for Fan-In configuration, the die is exposed to the atmosphere (no molding compound surrounding the die), leading to chemical contamination and cracks. Numerous causes are involved: e.g. non-optimized sawing process and weakness of the seal ring structure (i.e. metal pattern surrounding the die and providing mechanical and chemical shields). Furthermore, due to the bump and passivation layer proximities, some interactions may exist with the BEoL stack itself. FEM (Finite Element Method) is carried out, with a particular focus on the Fan-In package. Typical stress fields are provided, giving clues on WLCSP package specificities to mitigate mechanical hazard. Then, following the previously depicted failures, both the die and the passivation edges are comprehensively studied. It is shown that a stress peak is induced by the passivation edge, providing requirements on the deposit strategy (direct or pyramidal) and the edge location. Additionally, it is shown that the residual stress and the thickness of the BEoL passivation layer have also to be reduced and increased respectively.","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":"130487170","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.2016.7463305
A. Wymyslowski, A. Gorecka-Drzazga, K. Sareło
There are more and more sophisticated sensors in microsystem applications, which seem to rivet the engineers' attention. There is an extraordinary variety of sensors types which includes pressure, temperature, acceleration processing, optical, magnetic, chemical etc. In a number of sensors the critical sensing element most often is made of a silicon. The mechanical properties of silicon are outstanding and techniques for shaping it into complex three-dimensional structures are well known and mastered from the technological point of view. Most often MEMS sensor are integral part of any electronic system. The main attention of the current research was MEMS silicon pressure sensor based on an optical detection of a membrane deflection, which can be used for a pressure detection in harsh environment. The goal of the work was to apply a numerical simulation along with an analytical analysis, which were finally followed up and validated by the experimental results in order to define the sensor RSM (Response Surface Models) model, which can be used directly in complex numerical prototyping of electronic systems using, e.g. SPICE/VERILOG type of simulators.
{"title":"Analytical, numerical and experimental approach to analysis properties of a silicon membrane pressure sensor","authors":"A. Wymyslowski, A. Gorecka-Drzazga, K. Sareło","doi":"10.1109/EUROSIME.2016.7463305","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463305","url":null,"abstract":"There are more and more sophisticated sensors in microsystem applications, which seem to rivet the engineers' attention. There is an extraordinary variety of sensors types which includes pressure, temperature, acceleration processing, optical, magnetic, chemical etc. In a number of sensors the critical sensing element most often is made of a silicon. The mechanical properties of silicon are outstanding and techniques for shaping it into complex three-dimensional structures are well known and mastered from the technological point of view. Most often MEMS sensor are integral part of any electronic system. The main attention of the current research was MEMS silicon pressure sensor based on an optical detection of a membrane deflection, which can be used for a pressure detection in harsh environment. The goal of the work was to apply a numerical simulation along with an analytical analysis, which were finally followed up and validated by the experimental results in order to define the sensor RSM (Response Surface Models) model, which can be used directly in complex numerical prototyping of electronic systems using, e.g. SPICE/VERILOG type of simulators.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"55 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":"116571090","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.2016.7463396
Weihai Zhang, Daoguo Yang, L. Ernst, Bingbing Zhang, Wenbo Yang, M. Cai
For the MMB delamination experiments on CU-EMC interfaces as previously discussed in [1-6], the interface fracture shows the characteristics of a "brittle interface". This is because of the fact that the actual fracture appears between the brittle EMC and the brittle CU-oxides (being present on the CU lead-frame). Low cycle fatigue fracture or sub-critical fracture under cyclic loading conditions is generally considered not to be occurring for "brittle interfaces". Therefore, it was somewhat surprising that in [7] fatigue fracture was reported to occur for CU-EMC interfaces. The reason for this surprising behaviour could possibly be found in the overloading of the CU-substrate above its yield limit or just due to local plastic phenomena in the CU near the crack tip. In such a case the J-Integral value at the crack tip could possibly rise even under non-progressive cyclic loading. In order to research this phenomena for the MMB test of [1-6], a number of cyclic deformation simulations is applied to explore the J-Integral value for the case that the CU-lead-frame is being bend above its yield limit. In this paper following steps will be discussed: As during non-progressive cyclic loading extremely small changes of the J-Integral value are expected to occur and these should be well registered, first a separate comparison of the J-Integral evaluation of the MMB test for 3 different FEM packages is discussed (ANSYS, ABAQUS, MARC). The simulation results for the J-Integral values during non-progressive cyclic loading at room temperature (=Glassy state of the EMC), are evaluated. It occurs that Shake down to Elastic action occurs after the first cycles. As a result, based on the simulation results at room temperature, sub-critical fracture is not likely to occur. It is expected that at high temperatures (=Rubbery state of the EMC) again Shake down to Elastic action will occur after the first few cycles. Consequently, plastic behaviour in the CU is not considered as the root cause of sub-critical fracture. On the other hand, in packages under cyclic loading including high temperature, the exposure at high temperature will be accompanied by continuing aging of the EMC. In parallel research [15] it was found that due to aging of the EMC the deformation and stress state of a package is dramatically changing with time. This dramatically changing state could well be the origin of previously observed sub-critical fracture. Here further research will be required.
{"title":"Interface crack propagation between epoxy moulding compound and copper","authors":"Weihai Zhang, Daoguo Yang, L. Ernst, Bingbing Zhang, Wenbo Yang, M. Cai","doi":"10.1109/EUROSIME.2016.7463396","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463396","url":null,"abstract":"For the MMB delamination experiments on CU-EMC interfaces as previously discussed in [1-6], the interface fracture shows the characteristics of a \"brittle interface\". This is because of the fact that the actual fracture appears between the brittle EMC and the brittle CU-oxides (being present on the CU lead-frame). Low cycle fatigue fracture or sub-critical fracture under cyclic loading conditions is generally considered not to be occurring for \"brittle interfaces\". Therefore, it was somewhat surprising that in [7] fatigue fracture was reported to occur for CU-EMC interfaces. The reason for this surprising behaviour could possibly be found in the overloading of the CU-substrate above its yield limit or just due to local plastic phenomena in the CU near the crack tip. In such a case the J-Integral value at the crack tip could possibly rise even under non-progressive cyclic loading. In order to research this phenomena for the MMB test of [1-6], a number of cyclic deformation simulations is applied to explore the J-Integral value for the case that the CU-lead-frame is being bend above its yield limit. In this paper following steps will be discussed: As during non-progressive cyclic loading extremely small changes of the J-Integral value are expected to occur and these should be well registered, first a separate comparison of the J-Integral evaluation of the MMB test for 3 different FEM packages is discussed (ANSYS, ABAQUS, MARC). The simulation results for the J-Integral values during non-progressive cyclic loading at room temperature (=Glassy state of the EMC), are evaluated. It occurs that Shake down to Elastic action occurs after the first cycles. As a result, based on the simulation results at room temperature, sub-critical fracture is not likely to occur. It is expected that at high temperatures (=Rubbery state of the EMC) again Shake down to Elastic action will occur after the first few cycles. Consequently, plastic behaviour in the CU is not considered as the root cause of sub-critical fracture. On the other hand, in packages under cyclic loading including high temperature, the exposure at high temperature will be accompanied by continuing aging of the EMC. In parallel research [15] it was found that due to aging of the EMC the deformation and stress state of a package is dramatically changing with time. This dramatically changing state could well be the origin of previously observed sub-critical fracture. Here further research will be required.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"9 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":"133354445","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.2016.7463331
C. Byun, Sangki Park, Yonghan Lee, Sun-Kyu Lee
Laser-driven white lighting consists of blue laser diode (LD) and yellow phosphor, and it is attracting attention as a future lighting technology due to its advantages such as high luminous intensity, efficacy and the possibility of miniaturization. The optical efficiency of LD is highly affected by the temperature, cooling system is critical for many practical applications such as automotive headlamp. This study presents a single phase liquid cooling system which was selected for both higher cooling performance and lower consumption power. Also, a thermal dynamic model was proposed for predicting the LD temperature with experiment to validate the model. The system consists of an LD, heat spreader, heat sink and liquid pump. A heat spreader was designed with liquid cooling channels based on the model in consideration of both the thermal resistance and pressure drop. Also, the effect of surrounding ambient conditions was analyzed for considering real vehicle situation.
{"title":"Thermal dynamic modeling of laser diode cooling system considering surrounding ambient condition","authors":"C. Byun, Sangki Park, Yonghan Lee, Sun-Kyu Lee","doi":"10.1109/EUROSIME.2016.7463331","DOIUrl":"https://doi.org/10.1109/EUROSIME.2016.7463331","url":null,"abstract":"Laser-driven white lighting consists of blue laser diode (LD) and yellow phosphor, and it is attracting attention as a future lighting technology due to its advantages such as high luminous intensity, efficacy and the possibility of miniaturization. The optical efficiency of LD is highly affected by the temperature, cooling system is critical for many practical applications such as automotive headlamp. This study presents a single phase liquid cooling system which was selected for both higher cooling performance and lower consumption power. Also, a thermal dynamic model was proposed for predicting the LD temperature with experiment to validate the model. The system consists of an LD, heat spreader, heat sink and liquid pump. A heat spreader was designed with liquid cooling channels based on the model in consideration of both the thermal resistance and pressure drop. Also, the effect of surrounding ambient conditions was analyzed for considering real vehicle situation.","PeriodicalId":438097,"journal":{"name":"2016 17th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)","volume":"65 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":"130062947","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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