Pub Date : 2014-11-24DOI: 10.1109/ESTC.2014.6962856
Jemin Kim, B. Ma, K. Lee
To estimate influence of silicone encapsulant for ceramic LED package, we prepared silicone samples and ceramic LED packages used encapsulant as the same silicone with neither bonding adhesive nor phosphor. Also, a test jig was designed for high temperature operational life (HTOL) test on ceramic LED packages. The test jig made ceramic LED packages luminous, and was able to guide the light from ceramic LED packages to silicone samples. And then, thermal and optical stress tests on silicone samples were performed with HTOL test on ceramic LED packages in three different temperatures to compare the transmittance of the silicone samples according to the thermal and optical stress from ceramic LED packages. Transmittance of silicone sample and luminous flux of ceramic LED package were measured every 250 hours by UV-VIS spectrophotometer and integrating sphere, respectively. As results, more transmittance variations at 300~400 nm were inspected in silicone samples tested by thermal and optical stresses than by only thermal stress. And, the difference of transmittance characteristics was analyzed to find out how the silicone samples had changed during thermal and optical stress test with Raman analysis. In addition, the luminous flux of ceramic LED package was also changed during HTOL test according to transmittance variations in silicone samples.
{"title":"Study on influence of silicone encapsulant for ceramic LED package after HTOL test","authors":"Jemin Kim, B. Ma, K. Lee","doi":"10.1109/ESTC.2014.6962856","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962856","url":null,"abstract":"To estimate influence of silicone encapsulant for ceramic LED package, we prepared silicone samples and ceramic LED packages used encapsulant as the same silicone with neither bonding adhesive nor phosphor. Also, a test jig was designed for high temperature operational life (HTOL) test on ceramic LED packages. The test jig made ceramic LED packages luminous, and was able to guide the light from ceramic LED packages to silicone samples. And then, thermal and optical stress tests on silicone samples were performed with HTOL test on ceramic LED packages in three different temperatures to compare the transmittance of the silicone samples according to the thermal and optical stress from ceramic LED packages. Transmittance of silicone sample and luminous flux of ceramic LED package were measured every 250 hours by UV-VIS spectrophotometer and integrating sphere, respectively. As results, more transmittance variations at 300~400 nm were inspected in silicone samples tested by thermal and optical stresses than by only thermal stress. And, the difference of transmittance characteristics was analyzed to find out how the silicone samples had changed during thermal and optical stress test with Raman analysis. In addition, the luminous flux of ceramic LED package was also changed during HTOL test according to transmittance variations in silicone samples.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131256529","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962804
M. Detert, B. Schmidt, Franziska Wittig, David Wagner
The electronics packaging in microsystems technology for medical applications includes various tasks. The interdisciplinary approach is the most important basis for the success of a product. For the reliable operation of medical microsystems different factors must be considered. The functionalization of a catheter depends on different influence factors. The form factor takes the most important role. For a miniaturized and functional catheter tip, the diameter depends on the medical application. Other factors like the shape, reliability and also the cost must be considered. The paper shows the whole technology carrier of a medical product in relation to the field of electronics packaging.
{"title":"Electronics packaging technologies for the volume integration in components for medical tools and instruments","authors":"M. Detert, B. Schmidt, Franziska Wittig, David Wagner","doi":"10.1109/ESTC.2014.6962804","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962804","url":null,"abstract":"The electronics packaging in microsystems technology for medical applications includes various tasks. The interdisciplinary approach is the most important basis for the success of a product. For the reliable operation of medical microsystems different factors must be considered. The functionalization of a catheter depends on different influence factors. The form factor takes the most important role. For a miniaturized and functional catheter tip, the diameter depends on the medical application. Other factors like the shape, reliability and also the cost must be considered. The paper shows the whole technology carrier of a medical product in relation to the field of electronics packaging.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134233392","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962772
K. Aasmundtveit, T. Luu, Astrid-Sofie B. Vardøy, T. A. Tollefsen, Kaiying Wang, N. Hoivik
Solid-Liquid Interdiffusion (SLID) bonding is a promising bonding technique, particularly for high-temperature applications. Based on intermetallics as the bonding medium, the bonds are stable at temperatures far above the processing temperature which is in the range of normal solder temperatures. This work confirms experimentally this high-temperature stability through shear strength testing as function of temperature (room temperature to 300 °C) for three different SLID systems: Cu-Sn, Au-Sn and Au-In. All three systems remain solid within the tested temperature range, as expected, but they show remarkably different temperature dependence of mechanical strength: Au-Sn SLID bonds show strongly decreasing shear strength with temperature (but at 300 °C it is still well above the MIL-STD requirement); Cu-Sn SLID bonds show only small changes; whereas Au-In SLID bonds show increased shear strength at 300 °C, accompanied with a change in fracture mode from brittle to ductile. All three behaviours can be explained from the phase diagrams with the actual phases in use.
{"title":"High-temperature shear strength of solid-liquid interdiffusion (SLID) bonding: Cu-Sn, Au-Sn and Au-In","authors":"K. Aasmundtveit, T. Luu, Astrid-Sofie B. Vardøy, T. A. Tollefsen, Kaiying Wang, N. Hoivik","doi":"10.1109/ESTC.2014.6962772","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962772","url":null,"abstract":"Solid-Liquid Interdiffusion (SLID) bonding is a promising bonding technique, particularly for high-temperature applications. Based on intermetallics as the bonding medium, the bonds are stable at temperatures far above the processing temperature which is in the range of normal solder temperatures. This work confirms experimentally this high-temperature stability through shear strength testing as function of temperature (room temperature to 300 °C) for three different SLID systems: Cu-Sn, Au-Sn and Au-In. All three systems remain solid within the tested temperature range, as expected, but they show remarkably different temperature dependence of mechanical strength: Au-Sn SLID bonds show strongly decreasing shear strength with temperature (but at 300 °C it is still well above the MIL-STD requirement); Cu-Sn SLID bonds show only small changes; whereas Au-In SLID bonds show increased shear strength at 300 °C, accompanied with a change in fracture mode from brittle to ductile. All three behaviours can be explained from the phase diagrams with the actual phases in use.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"420 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134440235","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962802
M. Kościelski, J. Sitek
Conductive adhesives are widely used nowadays in electronic packaging eg. as a convenient way to connect chip on flexible substrate [1-3] such as Kapton foil, PEN foil, paper, thin epoxy laminate etc. Conductive adhesive mainly consist of organic polymer matrix and conductive fillers. Silver is widely the first choice as for its properties, electrical and thermal conductance and easy of producing the particles of different sizes and shapes. Silver is also beneficial because it's not prone towards oxidation. The drawback of the printed electronics is its longevity, as during time they degrade, that's why this technique is often used for simple assemblies such as RFID tags.
{"title":"Influence of curing conditions on mechanical properties and reliability of the interconnects made by ICA for printed electronics with micro additives","authors":"M. Kościelski, J. Sitek","doi":"10.1109/ESTC.2014.6962802","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962802","url":null,"abstract":"Conductive adhesives are widely used nowadays in electronic packaging eg. as a convenient way to connect chip on flexible substrate [1-3] such as Kapton foil, PEN foil, paper, thin epoxy laminate etc. Conductive adhesive mainly consist of organic polymer matrix and conductive fillers. Silver is widely the first choice as for its properties, electrical and thermal conductance and easy of producing the particles of different sizes and shapes. Silver is also beneficial because it's not prone towards oxidation. The drawback of the printed electronics is its longevity, as during time they degrade, that's why this technique is often used for simple assemblies such as RFID tags.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133175434","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962721
Wenbo Zhu, Fengshun Wu, Yanjun Xu, Changqing Liu
In this paper, patterned Cu and Si substrates are interconnected via solder alloys through Al/Ni self-propagating nano-film to obtain hermetical packaging for infrared detector. During the joining process, substrates which are coated with different solder layers (e.g. Sn and AuSn) are bonded under various atmospheres. By optimizing joining parameters, reliable metallurgical joints between Si/Cu and Si/Si can be achieved through self-propagating exothermic reaction process of Al/Ni multilayered nano-films. Thin IMC layers are observed at the bonding interfaces with some micro-voids being detected, but the bonding obtained is acceptable and can meet the requirements of the package of infrared sensors. Furthermore, the solder behavior and the formation of defects under different bonding conditions are compared to enable the optimization of the self-propagating joining process. To verify the reliability of self-propagating joints, the formed bonds are also evaluated in terms of IMCs formation and interfacial characteristics. In particular, the voids and potential leakage in joints are estimated through CSAM inspection. And the composition, morphology and defects in solder joints under different bonding conditions are also characterized based on the cross-sections of the joints. Finally, in comparison with traditional reflow process, the feasibility and advantages of self-propagating joining in hermetical package can articulated in the discussion.
{"title":"Hermetical package of infrared sensors by Al/Ni self-propagating joining process","authors":"Wenbo Zhu, Fengshun Wu, Yanjun Xu, Changqing Liu","doi":"10.1109/ESTC.2014.6962721","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962721","url":null,"abstract":"In this paper, patterned Cu and Si substrates are interconnected via solder alloys through Al/Ni self-propagating nano-film to obtain hermetical packaging for infrared detector. During the joining process, substrates which are coated with different solder layers (e.g. Sn and AuSn) are bonded under various atmospheres. By optimizing joining parameters, reliable metallurgical joints between Si/Cu and Si/Si can be achieved through self-propagating exothermic reaction process of Al/Ni multilayered nano-films. Thin IMC layers are observed at the bonding interfaces with some micro-voids being detected, but the bonding obtained is acceptable and can meet the requirements of the package of infrared sensors. Furthermore, the solder behavior and the formation of defects under different bonding conditions are compared to enable the optimization of the self-propagating joining process. To verify the reliability of self-propagating joints, the formed bonds are also evaluated in terms of IMCs formation and interfacial characteristics. In particular, the voids and potential leakage in joints are estimated through CSAM inspection. And the composition, morphology and defects in solder joints under different bonding conditions are also characterized based on the cross-sections of the joints. Finally, in comparison with traditional reflow process, the feasibility and advantages of self-propagating joining in hermetical package can articulated in the discussion.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129631744","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962862
A. Klemm, M. Oppermann, T. Zerna
In power electronics there is currently a development to higher operating temperatures of up to 300 °C. This was made possible by an improved availability of semiconductor materials such as silicon carbide. At these temperatures conventional solders can no longer be used for Die-Attachment. Therefore new technologies are necessary. One possible solution is to use diffusion soldering. Khaja et al. [1] presented an approach for diffusion soldering by printing of a conventional solder paste with a 20 μm thin stencil. In power the void content is typically required to be less than 10 %. Khaja et al. showed that the application of a vacuum vapour phase soldering process can ensure a very low void content of the resulting solder joints. In a previous paper we showed that vacuum soldering processes are in principle better suited for this purpose than overpressure processes [2]. In this work we found the same effects, which we observed in our previous work, also for conventional SAC305 solder paste on DCB substrates. Furthermore we investigated different vacuum soldering processes. We could not observe any apparent difference between vacuum soldering processes with several separate vacuum steps and processes with a single vacuum step. However the strength of the vacuum step influences the final void content significantly. Furthermore we found that void content over time curves of soldering processes without pressure changes exhibit a minimum. When a solder joint is kept at peak temperature for a longer period of time the void content steadily increases again. We showed that this can be suppressed with overpressure. Therefore we conclude that for diffusion soldering with long peak times of several minutes a combined soldering process of vacuum and overpressure steps is required.
{"title":"In-situ-X-ray investigation on vacuum soldering processes for conventional and diffusion soldering","authors":"A. Klemm, M. Oppermann, T. Zerna","doi":"10.1109/ESTC.2014.6962862","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962862","url":null,"abstract":"In power electronics there is currently a development to higher operating temperatures of up to 300 °C. This was made possible by an improved availability of semiconductor materials such as silicon carbide. At these temperatures conventional solders can no longer be used for Die-Attachment. Therefore new technologies are necessary. One possible solution is to use diffusion soldering. Khaja et al. [1] presented an approach for diffusion soldering by printing of a conventional solder paste with a 20 μm thin stencil. In power the void content is typically required to be less than 10 %. Khaja et al. showed that the application of a vacuum vapour phase soldering process can ensure a very low void content of the resulting solder joints. In a previous paper we showed that vacuum soldering processes are in principle better suited for this purpose than overpressure processes [2]. In this work we found the same effects, which we observed in our previous work, also for conventional SAC305 solder paste on DCB substrates. Furthermore we investigated different vacuum soldering processes. We could not observe any apparent difference between vacuum soldering processes with several separate vacuum steps and processes with a single vacuum step. However the strength of the vacuum step influences the final void content significantly. Furthermore we found that void content over time curves of soldering processes without pressure changes exhibit a minimum. When a solder joint is kept at peak temperature for a longer period of time the void content steadily increases again. We showed that this can be suppressed with overpressure. Therefore we conclude that for diffusion soldering with long peak times of several minutes a combined soldering process of vacuum and overpressure steps is required.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130766204","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962847
K. Pun, M. Islam, T. Ng
Recently Electroless Ni/Electroless Pd/Immersion Au (ENEPIG) is being offered as an alternative surface finish to established processing such as Immersion Sn, Immersion Ag, Organic solderability preservatives (OSP), Electrolytic Ni/Au (ENA), and electroless Ni/immersion Au (ENIG) surface finish. With high solder joint quality and wire bondability, it is claimed to be more cost effective as an Au layer of lower thickness can be used. The performance of solder joints upon ENA and ENEPIG surface finishes are evaluated by extended reflow tests at 245°C followed by ball shear testing. Following extended reflow, the ENEPIG/solder system provides lower shear strengths than the ENA/solder system. It is found that columnar Cu-Ni-Sn IMCs with small amount of Pd and P-rich Ni layer have formed at the interface of ENEPIG/solder system, causing brittle fracture with lower shear strength in the ball shear test. In contrast, layer-type Cu-Ni-Sn IMCs formed at the interface of ENA/solder system in the absence of Pd which caused ductile fracture in ball shear test. Therefore, it has been demonstrated that solder joint on ENA surface finish is more reliable and suitable to be used for long-term reliability of electronic products.
{"title":"Comparison between ENA and ENEPIG surface finish for high density TBGA package","authors":"K. Pun, M. Islam, T. Ng","doi":"10.1109/ESTC.2014.6962847","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962847","url":null,"abstract":"Recently Electroless Ni/Electroless Pd/Immersion Au (ENEPIG) is being offered as an alternative surface finish to established processing such as Immersion Sn, Immersion Ag, Organic solderability preservatives (OSP), Electrolytic Ni/Au (ENA), and electroless Ni/immersion Au (ENIG) surface finish. With high solder joint quality and wire bondability, it is claimed to be more cost effective as an Au layer of lower thickness can be used. The performance of solder joints upon ENA and ENEPIG surface finishes are evaluated by extended reflow tests at 245°C followed by ball shear testing. Following extended reflow, the ENEPIG/solder system provides lower shear strengths than the ENA/solder system. It is found that columnar Cu-Ni-Sn IMCs with small amount of Pd and P-rich Ni layer have formed at the interface of ENEPIG/solder system, causing brittle fracture with lower shear strength in the ball shear test. In contrast, layer-type Cu-Ni-Sn IMCs formed at the interface of ENA/solder system in the absence of Pd which caused ductile fracture in ball shear test. Therefore, it has been demonstrated that solder joint on ENA surface finish is more reliable and suitable to be used for long-term reliability of electronic products.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127977378","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962753
Xiaogang Fan, Xiaolei Li, W. Mu, D. Jiang, Shirong Huang, Yifeng Fu, Yan Zhang, Johan Liu
Carbon nanotubes (CNTs) are an ideal candidate material for electronic interconnects due to their extraordinary thermal, electrical and mechanical properties. In this study, densified CNT bumps utilizing the paper-mediated controlled method were applied as the interconnection for chip on glass (COG) applications, and the silicon chip with patterned CNT bumps was then flipped and bonded onto a glass substrate using anisotropic conductive adhesive (ACA) at a bonding pressure of 127.4 Mpa, 170°C for 8 seconds. The electrical properties of the COG were evaluated with the contact resistance of each bump measured using the four-point probe method. Three different structure traces, marked as Trace A, Trace B, and Trace C, were tested, respectively. Thermal cycling (-40 to 85°C, 800 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were also conducted to evaluate the reliability of the CNT-COG structure. The average contact resistance of the samples was recorded during these tests, in which there was no obvious electrical failure observed after both the thermal cycling and damp heat tests. The results of these tests indicated that the COG has good reliability and the CNT bumps have promising potential applications in COG.
{"title":"Reliability of carbon nanotube bumps for chip on glass application","authors":"Xiaogang Fan, Xiaolei Li, W. Mu, D. Jiang, Shirong Huang, Yifeng Fu, Yan Zhang, Johan Liu","doi":"10.1109/ESTC.2014.6962753","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962753","url":null,"abstract":"Carbon nanotubes (CNTs) are an ideal candidate material for electronic interconnects due to their extraordinary thermal, electrical and mechanical properties. In this study, densified CNT bumps utilizing the paper-mediated controlled method were applied as the interconnection for chip on glass (COG) applications, and the silicon chip with patterned CNT bumps was then flipped and bonded onto a glass substrate using anisotropic conductive adhesive (ACA) at a bonding pressure of 127.4 Mpa, 170°C for 8 seconds. The electrical properties of the COG were evaluated with the contact resistance of each bump measured using the four-point probe method. Three different structure traces, marked as Trace A, Trace B, and Trace C, were tested, respectively. Thermal cycling (-40 to 85°C, 800 cycles) and damp heat tests (85°C/85% RH, 1000 hours) were also conducted to evaluate the reliability of the CNT-COG structure. The average contact resistance of the samples was recorded during these tests, in which there was no obvious electrical failure observed after both the thermal cycling and damp heat tests. The results of these tests indicated that the COG has good reliability and the CNT bumps have promising potential applications in COG.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116515482","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962785
K. Pun, Anupam Sharma, Amandeep Singh, M. Islam, T. Ng
In system on flex (SOF) packages with high density I/O's, a number of factors induces concentrated stress field around the bonded areas (bumps & traces) during assembly process. For example, the choice of underfill / encapsulant and the associated processes could affect the package integrity. Poor control of the underfill process could potentially result in delamination on various interfaces. It also increases the chances of moisture absorption thus potentially results in electro-chemical corrosion of the stressed area which affects the package reliability. In this paper, we present the development of processes targeted at ensuring good underfill reliability. It is revealed that delamination is driven by either the adhesion failure within the substrate and underfill or by the stresses induced in the interfacial sites. We developed an extra cleaning process to remove seed-layer Cr+ to avoid adhesion failure due to contamination of flex. Filler type underfill material is found to give more strength than non-filler materials but at a cost of flow rate and capturing voids. Effect of peak temperature during assembly process was studied; this shows that through controlling the reflow temperature, the underfill integrity may be maintained which potentially allows more complex assembly processes. However, at the same time, poor control of the reflow temperature may significantly affect the underfill material causing it to deteriorate at a rapid rate. Further development into assembly processing at lower temperature would be beneficial for high reliability of SOF packages.
{"title":"Development of void free, high reliability underfill encapsulated fine pitch system on flex packages","authors":"K. Pun, Anupam Sharma, Amandeep Singh, M. Islam, T. Ng","doi":"10.1109/ESTC.2014.6962785","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962785","url":null,"abstract":"In system on flex (SOF) packages with high density I/O's, a number of factors induces concentrated stress field around the bonded areas (bumps & traces) during assembly process. For example, the choice of underfill / encapsulant and the associated processes could affect the package integrity. Poor control of the underfill process could potentially result in delamination on various interfaces. It also increases the chances of moisture absorption thus potentially results in electro-chemical corrosion of the stressed area which affects the package reliability. In this paper, we present the development of processes targeted at ensuring good underfill reliability. It is revealed that delamination is driven by either the adhesion failure within the substrate and underfill or by the stresses induced in the interfacial sites. We developed an extra cleaning process to remove seed-layer Cr+ to avoid adhesion failure due to contamination of flex. Filler type underfill material is found to give more strength than non-filler materials but at a cost of flow rate and capturing voids. Effect of peak temperature during assembly process was studied; this shows that through controlling the reflow temperature, the underfill integrity may be maintained which potentially allows more complex assembly processes. However, at the same time, poor control of the reflow temperature may significantly affect the underfill material causing it to deteriorate at a rapid rate. Further development into assembly processing at lower temperature would be beneficial for high reliability of SOF packages.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123529886","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 : 2014-11-24DOI: 10.1109/ESTC.2014.6962723
A. Solomon, A. Castellazzi
The recent research exercises have targeted the transfer of the sandwich package benefits to application bespoke switch design, including flipchip and device stacking topology [1]. This paper will present the work in an alternative integration scheme for a half-bridge switch using 70μm thin Si IGBTs and diodes addressing higher strength, higher toughness and higher thermal conductivity. Using alumina ceramic substrates are prone to failure compared to silicon nitride. The switch is totally wire bond less where bonded wires have large parasitic inductance which deteriorates the electromagnetic performance. In addition to the wire bond, the interconnection pattern plays a great roll of helping the loop current to be entirely vertical.
{"title":"Alternative integration scheme for half-bridge switch using double etched Si3N4 substrate","authors":"A. Solomon, A. Castellazzi","doi":"10.1109/ESTC.2014.6962723","DOIUrl":"https://doi.org/10.1109/ESTC.2014.6962723","url":null,"abstract":"The recent research exercises have targeted the transfer of the sandwich package benefits to application bespoke switch design, including flipchip and device stacking topology [1]. This paper will present the work in an alternative integration scheme for a half-bridge switch using 70μm thin Si IGBTs and diodes addressing higher strength, higher toughness and higher thermal conductivity. Using alumina ceramic substrates are prone to failure compared to silicon nitride. The switch is totally wire bond less where bonded wires have large parasitic inductance which deteriorates the electromagnetic performance. In addition to the wire bond, the interconnection pattern plays a great roll of helping the loop current to be entirely vertical.","PeriodicalId":299981,"journal":{"name":"Proceedings of the 5th Electronics System-integration Technology Conference (ESTC)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129106530","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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