K. Alzoubi, A. Hensel, Felix Häußler, B. Ottinger, Marcel Sippel, Joerg Franke
Power electronics is concerned with the use of electronic devices to control and transfer electric power from one form to another. Power electronics can be found in laptop chargers, electric grids, and solar inverters. Die-attach interconnections form a critical part of power electronics devices. Silver sintering is traditionally used for die-attach interconnections because of its high melting point and ability to form very thin thicknesses. However, the processing time compared with soldering is very long. Sintered layers might contain large voids that affect the mechanical stability of the structure. Stresses caused by mechanical and environmental conditions might cause degradation and possibly early failures. This work focuses on studying the combined effect of process factors on the shear strength of small-area die-attach interconnections in silver sintering. Design of Experiments (DoE) tools were used to build an experimental matrix with a 95% confidence level. The results have shown that holding time has a considerable effect on the mechanical stability of the die-attach interconnections. Intermetallic compounds formed in the sintered joints at higher holding times resulted in lesser voids. Furthermore, the treatment level of the holding time highly affects the shear strength under the other factors of temperature and pressure.
{"title":"Process-factor Optimization of Small-area Sintered Interconnects for Power Electronics Applications","authors":"K. Alzoubi, A. Hensel, Felix Häußler, B. Ottinger, Marcel Sippel, Joerg Franke","doi":"10.1115/1.4056992","DOIUrl":"https://doi.org/10.1115/1.4056992","url":null,"abstract":"\u0000 Power electronics is concerned with the use of electronic devices to control and transfer electric power from one form to another. Power electronics can be found in laptop chargers, electric grids, and solar inverters. Die-attach interconnections form a critical part of power electronics devices. Silver sintering is traditionally used for die-attach interconnections because of its high melting point and ability to form very thin thicknesses. However, the processing time compared with soldering is very long. Sintered layers might contain large voids that affect the mechanical stability of the structure. Stresses caused by mechanical and environmental conditions might cause degradation and possibly early failures. This work focuses on studying the combined effect of process factors on the shear strength of small-area die-attach interconnections in silver sintering. Design of Experiments (DoE) tools were used to build an experimental matrix with a 95% confidence level. The results have shown that holding time has a considerable effect on the mechanical stability of the die-attach interconnections. Intermetallic compounds formed in the sintered joints at higher holding times resulted in lesser voids. Furthermore, the treatment level of the holding time highly affects the shear strength under the other factors of temperature and pressure.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45102537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xuesong Zhang, Qian Wang, Chenhui Xia, Chaojie Zhou, Gang Wang, Jian Cai
The technology of fan-out wafer level packaging (FOWLP) has been widely adopted for millimeter wave Antenna-in-Package (AiP) system integration with low interconnection parasitic parameters. Present AiP solutions using FOWLP technology generally form antenna pattern on Redistribution Layer, which brings design inconvenience. In our work, a low-cost PCB antenna with relatively large size is integrated, forms three-dimensional stacked structure. The AiP employs right angle transition board embedded in Epoxy molding compound (EMC), which transmits mm-wave signal to the substrate-integrated waveguide (SIW) antenna stacked on the back of EMC. The SIW antenna consists of 4x4 radiation slots with modified magnetoelectric dipole for bandwidth enhancement. Measured gain is 14dBi at 60GHz with bandwidth beyond 55-65GHz. The SIW antenna works also as heat sink, no extra thermal design is needed for 0.5W power consumption. The AiP module is manufactured and measured on circuit board. The proposed approach is a convenient solution for wide band and high gain millimeter wave AiP system integration.
{"title":"High Gain and Wideband Antenna-in-package Solution Using Fan-out Technology","authors":"Xuesong Zhang, Qian Wang, Chenhui Xia, Chaojie Zhou, Gang Wang, Jian Cai","doi":"10.1115/1.4056991","DOIUrl":"https://doi.org/10.1115/1.4056991","url":null,"abstract":"\u0000 The technology of fan-out wafer level packaging (FOWLP) has been widely adopted for millimeter wave Antenna-in-Package (AiP) system integration with low interconnection parasitic parameters. Present AiP solutions using FOWLP technology generally form antenna pattern on Redistribution Layer, which brings design inconvenience. In our work, a low-cost PCB antenna with relatively large size is integrated, forms three-dimensional stacked structure. The AiP employs right angle transition board embedded in Epoxy molding compound (EMC), which transmits mm-wave signal to the substrate-integrated waveguide (SIW) antenna stacked on the back of EMC. The SIW antenna consists of 4x4 radiation slots with modified magnetoelectric dipole for bandwidth enhancement. Measured gain is 14dBi at 60GHz with bandwidth beyond 55-65GHz. The SIW antenna works also as heat sink, no extra thermal design is needed for 0.5W power consumption. The AiP module is manufactured and measured on circuit board. The proposed approach is a convenient solution for wide band and high gain millimeter wave AiP system integration.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44521201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Doranga, Dongji Xie, J. Lee, Andy Zhang, Xue Shi, Valeriy Khaldarov
The fatigue life prediction of the electronic packages under dynamic loading conditions is an increasingly important area of research, with direct application in packaging industries. Current life prediction methodologies are, in general, developed through a finite element (FE) model that is correlated using an experimental data measured through sweep sine testing. The frequency response curve (FRF) generated by using a sweep sine testing may suffer from leakage and windowing of the signal may not work correctly, which results in the shift in the amplitude and the resonance frequencies of the package. In consequence, there will be a significant deviation between the actual and the predicted natural frequencies and the amplitude of vibration response in the given excitation range, resulting in the longer time to fail the package during the laboratory based /virtual durability testing. Thus, it is necessary to develop a suitable validation technique in time/frequency domain to address this issue. In this paper, the step sine testing procedure is utilized to validate the FE model of a test vehicle consisting of a board level BGA chip package and the resonance based fatigue testing is performed in the FE based simulation. The global-local modeling approach is utilized to model the test vehicle and the volume average von Mises stress is used to predict the life of the solder joint. Following the numerical simulations, fatigue test is carried out in the test vehicle at the first resonance frequency obtained from the step sine test. Experimental results show that there are full openings of the corner balls in a very short interval of time. The results of the life prediction from the FE model and from experiments are comparable to each other thus validating the proposed methodology.
{"title":"A Time Frequency Domain Based Approach for Bga Solder Joint Fatigue Analysis Using Global Local Modeling Technique","authors":"S. Doranga, Dongji Xie, J. Lee, Andy Zhang, Xue Shi, Valeriy Khaldarov","doi":"10.1115/1.4056886","DOIUrl":"https://doi.org/10.1115/1.4056886","url":null,"abstract":"\u0000 The fatigue life prediction of the electronic packages under dynamic loading conditions is an increasingly important area of research, with direct application in packaging industries. Current life prediction methodologies are, in general, developed through a finite element (FE) model that is correlated using an experimental data measured through sweep sine testing. The frequency response curve (FRF) generated by using a sweep sine testing may suffer from leakage and windowing of the signal may not work correctly, which results in the shift in the amplitude and the resonance frequencies of the package. In consequence, there will be a significant deviation between the actual and the predicted natural frequencies and the amplitude of vibration response in the given excitation range, resulting in the longer time to fail the package during the laboratory based /virtual durability testing. Thus, it is necessary to develop a suitable validation technique in time/frequency domain to address this issue. In this paper, the step sine testing procedure is utilized to validate the FE model of a test vehicle consisting of a board level BGA chip package and the resonance based fatigue testing is performed in the FE based simulation. The global-local modeling approach is utilized to model the test vehicle and the volume average von Mises stress is used to predict the life of the solder joint. Following the numerical simulations, fatigue test is carried out in the test vehicle at the first resonance frequency obtained from the step sine test. Experimental results show that there are full openings of the corner balls in a very short interval of time. The results of the life prediction from the FE model and from experiments are comparable to each other thus validating the proposed methodology.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49644543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Reviewers of the Year Award is given to reviewers who have made an outstanding contribution to the journal in terms of the quantity, quality, and turnaround time of reviews completed during the past 12 months. The prize includes a Wall Plaque, 50 free downloads from the ASME Digital Collection, and a one year free subscription to the journal.T. AnH. BaiM. BudakliF. CheJ. ChenT. ChenH. ChengT. ChiuM. ChowdhuryO. DalvernyB. DogruozC. GanR. GhaffarianD. Gonzalez CuadradoC. GreenP. GromalaM. GuptaY. HuangD. HuitinkT. IkedaC. KapustaB. KellyC. KhorH. LeeD. LiuA. MianK. MysoreD. NarasimhanJ. NiG. OnushkinD. PahinkarD. PantusoS. ParupalliG. PavlidisD. Ramos AlvaradoD. RaoM. ShihA. SinghJ. TsaiA. UdupaA. UsmanM. Van DijkW. Van DrielM. Van SoestbergenG. WangR. WarzohaJ. XuJ. YangM. Yazdan MehrA. YeoD. YuC. YuanZ. ZhangS. ZhaoQ. Zheng
{"title":"Reviewer's Recognition","authors":"","doi":"10.1115/1.4056725","DOIUrl":"https://doi.org/10.1115/1.4056725","url":null,"abstract":"The Reviewers of the Year Award is given to reviewers who have made an outstanding contribution to the journal in terms of the quantity, quality, and turnaround time of reviews completed during the past 12 months. The prize includes a Wall Plaque, 50 free downloads from the ASME Digital Collection, and a one year free subscription to the journal.T. AnH. BaiM. BudakliF. CheJ. ChenT. ChenH. ChengT. ChiuM. ChowdhuryO. DalvernyB. DogruozC. GanR. GhaffarianD. Gonzalez CuadradoC. GreenP. GromalaM. GuptaY. HuangD. HuitinkT. IkedaC. KapustaB. KellyC. KhorH. LeeD. LiuA. MianK. MysoreD. NarasimhanJ. NiG. OnushkinD. PahinkarD. PantusoS. ParupalliG. PavlidisD. Ramos AlvaradoD. RaoM. ShihA. SinghJ. TsaiA. UdupaA. UsmanM. Van DijkW. Van DrielM. Van SoestbergenG. WangR. WarzohaJ. XuJ. YangM. Yazdan MehrA. YeoD. YuC. YuanZ. ZhangS. ZhaoQ. Zheng","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136252175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims to demonstrate the biaxial bending strength test on thin silicon dies using the classic ball-on-ring (BoR) test, and discuss it in detail by comparing those results with the newly-proposed point load on elastic foundation (PoEF) test. The geometric linear and nonlinear solutions to the BoR test are reviewed and also provided with theoretical and numerical formulations, respectively. Three different thicknesses (t = 42 μm, 57 μm and 82 μm) of the thin silicon dies (with a size of 10 mm × 10 mm) are tested in the BoR test, and their bending strengths, load-displacement curves and failure modes are presented and thoroughly discussed with a comparison of the published data from the PoEF test. It is found that, for the bending strengths of 57 μm and 82 μm-thick dies, the data from both the BoR and PoEF tests are very consistent, but not for 42 μm-thick dies with a relatively lower value in the BoR test. This lower strength value in the BoR test is attributed to the more pronounced local buckling effect than the PoEF test. Based on that, it can concluded that the PoEF test is better and more reliable than the conventional BoR as for testing the ultra-thin silicon dies, even though both tests are identical for the regularly thin dies.
{"title":"A Comparison of Biaxial Bending Strength of Thin Silicon Dies in the BoR and PoEF Tests","authors":"M. Tsai, T. Kuo","doi":"10.1115/1.4056717","DOIUrl":"https://doi.org/10.1115/1.4056717","url":null,"abstract":"\u0000 This paper aims to demonstrate the biaxial bending strength test on thin silicon dies using the classic ball-on-ring (BoR) test, and discuss it in detail by comparing those results with the newly-proposed point load on elastic foundation (PoEF) test. The geometric linear and nonlinear solutions to the BoR test are reviewed and also provided with theoretical and numerical formulations, respectively. Three different thicknesses (t = 42 μm, 57 μm and 82 μm) of the thin silicon dies (with a size of 10 mm × 10 mm) are tested in the BoR test, and their bending strengths, load-displacement curves and failure modes are presented and thoroughly discussed with a comparison of the published data from the PoEF test. It is found that, for the bending strengths of 57 μm and 82 μm-thick dies, the data from both the BoR and PoEF tests are very consistent, but not for 42 μm-thick dies with a relatively lower value in the BoR test. This lower strength value in the BoR test is attributed to the more pronounced local buckling effect than the PoEF test. Based on that, it can concluded that the PoEF test is better and more reliable than the conventional BoR as for testing the ultra-thin silicon dies, even though both tests are identical for the regularly thin dies.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48252437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Flexible devices, which are seen as the future of the electronics industry, require encapsulation for protection while meeting the flexibility requirements of end applications. Flexible electronics have lower production costs and are thinner, lighter, and nonbreakable, resulting in a new form of application for electronic devices. One such use is the employment of electronic gadgets in the daily surroundings to monitor one's vitals. These devices are frequently exposed to dust, perspiration, and moisture. They are frequently subjected to bending and folding action, which causes stresses to accumulate in those devices. These stressors and the hostile environment are frequently minimized by using potting encapsulants to increase durability. In our investigation, we picked six distinct encapsulant formulations and exposed them to varied cure profiles to measure the adhesive bond strength of the encapsulants. The benchmark peel strength was constructed using a Finite element model of the AU-biometric band. The encapsulants peel strength was used to determine which material performed best under experimental conditions. This study presents a sample geometry comprising six different encapsulants and two distinct substrates, polyimide and PET, which were evaluated at four different cure schedules and cleaned using two different cleaning procedures. The encapsulants are ranked against one another to determine their potential future usage in flexible hybrid electronics (FHE) devices.
{"title":"Interaction of Surface Preparation and Cure Parameters on the Interface Reliability of Flexible Encapsulation in Flexible Hybrid Electronics Applications","authors":"Pradeep Lall, Padmanava Choudhury, Scott Miller","doi":"10.1115/1.4056477","DOIUrl":"https://doi.org/10.1115/1.4056477","url":null,"abstract":"Abstract Flexible devices, which are seen as the future of the electronics industry, require encapsulation for protection while meeting the flexibility requirements of end applications. Flexible electronics have lower production costs and are thinner, lighter, and nonbreakable, resulting in a new form of application for electronic devices. One such use is the employment of electronic gadgets in the daily surroundings to monitor one's vitals. These devices are frequently exposed to dust, perspiration, and moisture. They are frequently subjected to bending and folding action, which causes stresses to accumulate in those devices. These stressors and the hostile environment are frequently minimized by using potting encapsulants to increase durability. In our investigation, we picked six distinct encapsulant formulations and exposed them to varied cure profiles to measure the adhesive bond strength of the encapsulants. The benchmark peel strength was constructed using a Finite element model of the AU-biometric band. The encapsulants peel strength was used to determine which material performed best under experimental conditions. This study presents a sample geometry comprising six different encapsulants and two distinct substrates, polyimide and PET, which were evaluated at four different cure schedules and cleaned using two different cleaning procedures. The encapsulants are ranked against one another to determine their potential future usage in flexible hybrid electronics (FHE) devices.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136082367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Garakani, Udara S. Somarathna, Ashraf Umar, G. Khinda, M. Y. Abdelatty, EI Mehdi Abbara, Sari Al Zerey, M. Hopkins, Sai Srinivas, Chuck Kinzel, Christopher Halseth, M. Ronay, M. Poliks
Liquid metal-based gallium conductors exhibit unique physical and electromechanical properties, which make them excellent candidates for the next generation of wearable electronics. In this study, a novel fluid phase-based gallium conductor was stencil printed on thermoplastic polyurethane (TPU) to fabricate a stretchable conductor as well as a stretchable radio frequency (RF) transmission line. The electromechanical reliability of the conductor during high elongation as well as cyclic tension and bend fatigue was evaluated and compared with commercially available stretchable silver-filled polymer paste. The microstructure of the liquid metal conductor and the silver paste was investigated via scanning electron microscopy (SEM) before and after the samples were subjected to high elongation (> 100%). Unlike the silver paste, the liquid metal conductor maintained its microstructural integrity while its resistance showed a linear response to changes in length. A cyclic tension fatigue test confirmed the fatigue-free performance of the liquid metal conductor during 8,000 stretching cycles at a strain amplitude of 30%. The electromagnetic structure of the RF transmission line was simulated and then compared to the measured data. The measurements for insertion loss showed that U-bending, 90o twisting, and 1000 stretching cycles at a strain amplitude of 100% did not have a significant impact on the RF performance. Details of the DC tests and RF measurements, including the microstructural analysis and simulation results, will be discussed in this article.
{"title":"Investigation of Electromechanical Reliability and Radio Frequency Performance of a Highly Stretchable Liquid Metal Conductor for Wearable Electronics","authors":"B. Garakani, Udara S. Somarathna, Ashraf Umar, G. Khinda, M. Y. Abdelatty, EI Mehdi Abbara, Sari Al Zerey, M. Hopkins, Sai Srinivas, Chuck Kinzel, Christopher Halseth, M. Ronay, M. Poliks","doi":"10.1115/1.4056640","DOIUrl":"https://doi.org/10.1115/1.4056640","url":null,"abstract":"\u0000 Liquid metal-based gallium conductors exhibit unique physical and electromechanical properties, which make them excellent candidates for the next generation of wearable electronics. In this study, a novel fluid phase-based gallium conductor was stencil printed on thermoplastic polyurethane (TPU) to fabricate a stretchable conductor as well as a stretchable radio frequency (RF) transmission line. The electromechanical reliability of the conductor during high elongation as well as cyclic tension and bend fatigue was evaluated and compared with commercially available stretchable silver-filled polymer paste. The microstructure of the liquid metal conductor and the silver paste was investigated via scanning electron microscopy (SEM) before and after the samples were subjected to high elongation (> 100%). Unlike the silver paste, the liquid metal conductor maintained its microstructural integrity while its resistance showed a linear response to changes in length. A cyclic tension fatigue test confirmed the fatigue-free performance of the liquid metal conductor during 8,000 stretching cycles at a strain amplitude of 30%. The electromagnetic structure of the RF transmission line was simulated and then compared to the measured data. The measurements for insertion loss showed that U-bending, 90o twisting, and 1000 stretching cycles at a strain amplitude of 100% did not have a significant impact on the RF performance. Details of the DC tests and RF measurements, including the microstructural analysis and simulation results, will be discussed in this article.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43388044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the crucial factors in determining the reliability of an electronic device is fatigue failure of the interconnecting solder joints. In most cases, large bulk samples are used to study the fatigue characteristics of the solder materials. Real solder joints often encountered in ball grid array (BGA) components have only been considered in limited investigations. In this study, a specialized sandwich BGA test vehicle with a 3×3 solder joint was connected to the two substrates. The alloys were tested at room temperature using an Instron micromechanical tester in both the stress-controlled and strain-controlled methods. The tests were performed at a constant strain rate. Four stresses and four strain levels of the solder alloy Sn-3.0Ag-0.5Cu (SAC305) were examined using organic solderability preservative (OSP) and electroless nickel-immersion silver (ENIG) surface finishes. The work per cycle and plastic strain range were computed based on a systematic recording of the stress-strain (hysteresis) loops of each sample. A novel approach based on inelastic work is developed to calculate the fatigue life of a BGA assembled test vehicle. The results of the stress-controlled and strain-controlled tests indicated that the OSP surface finish outperformed the ENIG surface finish. Regardless of the testing process and surface finish, the Coffin-Manson and Morrow energy models were acceptable for SAC305.
{"title":"Assessing the SAC305 Solder Joint Fatigue in BGA Assembly Using Strain-Controlled and Stress-Controlled Approaches","authors":"Xin Wei, S. Hamasha, Ali Alahmer, M. Belhadi","doi":"10.1115/1.4056559","DOIUrl":"https://doi.org/10.1115/1.4056559","url":null,"abstract":"\u0000 One of the crucial factors in determining the reliability of an electronic device is fatigue failure of the interconnecting solder joints. In most cases, large bulk samples are used to study the fatigue characteristics of the solder materials. Real solder joints often encountered in ball grid array (BGA) components have only been considered in limited investigations. In this study, a specialized sandwich BGA test vehicle with a 3×3 solder joint was connected to the two substrates. The alloys were tested at room temperature using an Instron micromechanical tester in both the stress-controlled and strain-controlled methods. The tests were performed at a constant strain rate. Four stresses and four strain levels of the solder alloy Sn-3.0Ag-0.5Cu (SAC305) were examined using organic solderability preservative (OSP) and electroless nickel-immersion silver (ENIG) surface finishes. The work per cycle and plastic strain range were computed based on a systematic recording of the stress-strain (hysteresis) loops of each sample. A novel approach based on inelastic work is developed to calculate the fatigue life of a BGA assembled test vehicle. The results of the stress-controlled and strain-controlled tests indicated that the OSP surface finish outperformed the ENIG surface finish. Regardless of the testing process and surface finish, the Coffin-Manson and Morrow energy models were acceptable for SAC305.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41283521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jin Yang, P. Gromala, Sukwon Choi, D. Agonafer, P. McCluskey
{"title":"Special Section on InterPACK2021","authors":"Jin Yang, P. Gromala, Sukwon Choi, D. Agonafer, P. McCluskey","doi":"10.1115/1.4056558","DOIUrl":"https://doi.org/10.1115/1.4056558","url":null,"abstract":"","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46876833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible electronics are electronic devices and components that can be stretched, bent, twisted, and folded without losing their functionality. Flexible electronics is conformable, lightweight, easily tailorable, and low-cost, and thus, flexible electronics is increasingly being explored in health care, internet of things, automotive, aerospace, communication, safety, security, and food-related applications. Also, flexible electronics can now support increased functionality as well as various fabrication techniques. With an increased adaptation of flexible electronics, research is being conducted to better understand the failure mechanism of flexible electronics and thus improve their reliability and service life. In this paper, a cyclic mandrel bend test has been designed and carried out on printed conductors with PET and PI substrates. With the designed test apparatus, both tensile and compressive bend tests have been performed. Using a 4-wire method, the resistance change of the printed conductors with different widths has been measured in-situ under tensile and compressive loading conditions using mandrels with different radii. The results have been compared among different conductor widths, bending modes, and substrate materials. Besides, in-situ SEM images have been taken to understand the failure mechanisms of the printed conductors. Based on the study, it is seen that there exists a direct correlation between the mandrel diameter, the damage in the printed conductor, and thus, the resistance change with cyclic mandrel testing. Also, it is seen that the damage under compressive bending mode is significantly lower than the damage under tensile bending mode.
{"title":"Mandrel Bend Test of Screen-Printed Silver Conductors","authors":"R. Chen, Justin H. Chow, Yi Zhou, S. Sitaraman","doi":"10.1115/1.4056530","DOIUrl":"https://doi.org/10.1115/1.4056530","url":null,"abstract":"\u0000 Flexible electronics are electronic devices and components that can be stretched, bent, twisted, and folded without losing their functionality. Flexible electronics is conformable, lightweight, easily tailorable, and low-cost, and thus, flexible electronics is increasingly being explored in health care, internet of things, automotive, aerospace, communication, safety, security, and food-related applications. Also, flexible electronics can now support increased functionality as well as various fabrication techniques. With an increased adaptation of flexible electronics, research is being conducted to better understand the failure mechanism of flexible electronics and thus improve their reliability and service life. In this paper, a cyclic mandrel bend test has been designed and carried out on printed conductors with PET and PI substrates. With the designed test apparatus, both tensile and compressive bend tests have been performed. Using a 4-wire method, the resistance change of the printed conductors with different widths has been measured in-situ under tensile and compressive loading conditions using mandrels with different radii. The results have been compared among different conductor widths, bending modes, and substrate materials. Besides, in-situ SEM images have been taken to understand the failure mechanisms of the printed conductors. Based on the study, it is seen that there exists a direct correlation between the mandrel diameter, the damage in the printed conductor, and thus, the resistance change with cyclic mandrel testing. Also, it is seen that the damage under compressive bending mode is significantly lower than the damage under tensile bending mode.","PeriodicalId":15663,"journal":{"name":"Journal of Electronic Packaging","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48899602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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