Pub Date : 2009-10-01DOI: 10.1109/IMPACT.2009.5382243
B. Wessling, J. Kenny
For the first time, a thin layer of only a few nano-meters has been deposited onto copper pads of printed circuit boards which provides effective protection against oxidation and preserves its solderability. The Nano layer has a thickness of nominally only 50 nm, and contains the Organic Metal (conductive polymer) and a small amount of silver. With ≪ 90% (by volume), the Organic Metal is the major component of the deposited layer, Ag is present equivalent to a thickness of 4 nm. This Organic Metal - Ag complex final finish outperforms any established surface finishes.
{"title":"Nanotechnology for lead-free PWB final finishes with the Organic Metal","authors":"B. Wessling, J. Kenny","doi":"10.1109/IMPACT.2009.5382243","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382243","url":null,"abstract":"For the first time, a thin layer of only a few nano-meters has been deposited onto copper pads of printed circuit boards which provides effective protection against oxidation and preserves its solderability. The Nano layer has a thickness of nominally only 50 nm, and contains the Organic Metal (conductive polymer) and a small amount of silver. With ≪ 90% (by volume), the Organic Metal is the major component of the deposited layer, Ag is present equivalent to a thickness of 4 nm. This Organic Metal - Ag complex final finish outperforms any established surface finishes.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"23 1","pages":"554-557"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85191867","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382309
C. Y. Tang, C. Chen, M. Tsai
The purpose of this study is to investigate the optical behaviors and thus maximize luminous efficiency (focusing on light extraction efficiency here) of high-power chip-on-plate (COP) LED packages with the low-cost feature. First of all, to validate the luminous flux and candela distribution measurements and TracePro (one of commercial optical software) simulation, a Lumiled K1 LED package (one of commercially-available packages) is analyzed numerically and experimentally and compared with given data sheet. After the validation, both measurements and TracePro are applied to studying the candela distribution and light extraction efficiency of the COP LED packages. Furthermore, parametric studies of lens cavity height-radius ratio (h/r) and cup angle of COP LED packages using TracePro are implemented to find out the key factors to the light extraction efficiency. The results show that the candela distribution of COP LED packages from TracePro simulation is consistent with that from experiments. In optical parametric study, the effect of lens cavity height-radius ratio (h/r) of the COP LED packages on light extraction is found to be negligible, except for h/r=0. Moreover, with given lens cavity, the effect of air gap between silicone encapsulant and lens on light extraction is apparent by a way that air gap decreases with increasing light extraction. Also, it is found that the cup angle below 60° does not apparently affect light extraction, but beyond 60°, light extraction increases with the cup angle.
{"title":"Optical analysis and measurements of high-power COP LED packages","authors":"C. Y. Tang, C. Chen, M. Tsai","doi":"10.1109/IMPACT.2009.5382309","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382309","url":null,"abstract":"The purpose of this study is to investigate the optical behaviors and thus maximize luminous efficiency (focusing on light extraction efficiency here) of high-power chip-on-plate (COP) LED packages with the low-cost feature. First of all, to validate the luminous flux and candela distribution measurements and TracePro (one of commercial optical software) simulation, a Lumiled K1 LED package (one of commercially-available packages) is analyzed numerically and experimentally and compared with given data sheet. After the validation, both measurements and TracePro are applied to studying the candela distribution and light extraction efficiency of the COP LED packages. Furthermore, parametric studies of lens cavity height-radius ratio (h/r) and cup angle of COP LED packages using TracePro are implemented to find out the key factors to the light extraction efficiency. The results show that the candela distribution of COP LED packages from TracePro simulation is consistent with that from experiments. In optical parametric study, the effect of lens cavity height-radius ratio (h/r) of the COP LED packages on light extraction is found to be negligible, except for h/r=0. Moreover, with given lens cavity, the effect of air gap between silicone encapsulant and lens on light extraction is apparent by a way that air gap decreases with increasing light extraction. Also, it is found that the cup angle below 60° does not apparently affect light extraction, but beyond 60°, light extraction increases with the cup angle.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"17 1","pages":"60-62"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85385352","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382250
B. Chang, C. Hsiao, Ping-Chi Hung, C. T. Wang
There are four topics have been discussed in this paper via numerical simulation which include on board placement, stand-off, redundancy design and outlet condition. The simulation is performed for 1U with 200W and 2U system with 700W, respectively. This paper also provides the some solutions for each topic and reveals the thermal phenomena in these two systems. The proper placement can reduce the loading of thermal design, and it will make the design easier. The effect of stand-off is important in 1U system and will limited to the thermal performance of CPU cooler. For redundancy design, the flow field may be complex due to re-flow. The outlet condition will also affect the thermal performance, the other possible solutions have been mentioned in this paper.
{"title":"Thermal design strategy of server and storage products for 1U and 2U system","authors":"B. Chang, C. Hsiao, Ping-Chi Hung, C. T. Wang","doi":"10.1109/IMPACT.2009.5382250","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382250","url":null,"abstract":"There are four topics have been discussed in this paper via numerical simulation which include on board placement, stand-off, redundancy design and outlet condition. The simulation is performed for 1U with 200W and 2U system with 700W, respectively. This paper also provides the some solutions for each topic and reveals the thermal phenomena in these two systems. The proper placement can reduce the loading of thermal design, and it will make the design easier. The effect of stand-off is important in 1U system and will limited to the thermal performance of CPU cooler. For redundancy design, the flow field may be complex due to re-flow. The outlet condition will also affect the thermal performance, the other possible solutions have been mentioned in this paper.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"26 1","pages":"577-580"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91170655","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382212
M. Tsai, Yen-liang Lin, C. Kao
There are several identified failure mechanisms such as void formation and propagation, the local melting mechanism and the underbump metallization (UBM) dissolution in flip chip solder joints. In our previous studies Ni(V) UBM consumption was also found to cause the failure. The flip chip solder joint used in this study was with Al/Ni(V)/Cu UBM on the chip side and an Au/Ni surface finish on the substrate side. The solder was used by eutectic PbSn. The aging temperature was constant 150°C and a 0.32A current stressing was applied to make a nominal current density of 5 x 103A/cm2. Owing to the combined effects of current crowding and local Joule heating, the microstructure of the Ni(V) UBM near the entrance of the electrons into the joints was transformed to a porous structure after 550 hours. Afterwards the porous structure propagated all over the UBM to make the solder joints fail since the porous structure was non-conductive. The microstructure was firstly observed by field emission scanning electron microscopy (FE-SEM) and subsequently focused ion beam (FIB) was used to fabricate specimens for transmission electron microscopy (TEM) observation. The porous structure was composed of many voids near the interface of Ni(V)/(Cu,Ni)6Sn5 and a void-free area near the interface of Ni(V)/Al. Energy dispersion X-ray (EDX) analysis on TEM was performed for composition analyses. In the porous structure almost no Ni signal was detected except for the region near the interface of Ni(V)/Al. Pb-rich dark patches observed in the porous structure revealed that a severe diffusion behavior was occurred during electromigration. Selected area diffraction patterns (SADPs) were derived to identify phases. The results showed that the matrix of the porous structure was amorphous. Fine grains of Cu6Sn5 and V2Sn3 were randomly distributed in the matrix of the porous structure and a thin layer of Ni3Sn4 was located at the interface of Ni(V)/Al.
{"title":"Transmission electron microscopy characterization of the porous structure induced by high current density in the flip-chip solder joints","authors":"M. Tsai, Yen-liang Lin, C. Kao","doi":"10.1109/IMPACT.2009.5382212","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382212","url":null,"abstract":"There are several identified failure mechanisms such as void formation and propagation, the local melting mechanism and the underbump metallization (UBM) dissolution in flip chip solder joints. In our previous studies Ni(V) UBM consumption was also found to cause the failure. The flip chip solder joint used in this study was with Al/Ni(V)/Cu UBM on the chip side and an Au/Ni surface finish on the substrate side. The solder was used by eutectic PbSn. The aging temperature was constant 150°C and a 0.32A current stressing was applied to make a nominal current density of 5 x 103A/cm2. Owing to the combined effects of current crowding and local Joule heating, the microstructure of the Ni(V) UBM near the entrance of the electrons into the joints was transformed to a porous structure after 550 hours. Afterwards the porous structure propagated all over the UBM to make the solder joints fail since the porous structure was non-conductive. The microstructure was firstly observed by field emission scanning electron microscopy (FE-SEM) and subsequently focused ion beam (FIB) was used to fabricate specimens for transmission electron microscopy (TEM) observation. The porous structure was composed of many voids near the interface of Ni(V)/(Cu,Ni)6Sn5 and a void-free area near the interface of Ni(V)/Al. Energy dispersion X-ray (EDX) analysis on TEM was performed for composition analyses. In the porous structure almost no Ni signal was detected except for the region near the interface of Ni(V)/Al. Pb-rich dark patches observed in the porous structure revealed that a severe diffusion behavior was occurred during electromigration. Selected area diffraction patterns (SADPs) were derived to identify phases. The results showed that the matrix of the porous structure was amorphous. Fine grains of Cu6Sn5 and V2Sn3 were randomly distributed in the matrix of the porous structure and a thin layer of Ni3Sn4 was located at the interface of Ni(V)/Al.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"24 1","pages":"444-447"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91315343","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382170
A. Wu, H. Tseng, C. Wan, Yan-Kuin Su, Chenming Hu, S. Tsau
The InGaAs/GaAs multi-quantum-well as well as the AlGaAs/GaAs and the GaAsP/GaAs super-lattice laser diodes were successfully fabricated by low-pressure MOCVD system, and a number of novel structures were explored in this systematic investigation. The strain-relief effect and the composition of cladding layers were analyzed in detail. Via a series of growth experiments, we concluded that better lasing efficiency and the minimum threshold current could be obtained from the sample made up of the AlGaAs/GaAs structure combined with the 60% Aluminum content of the AlGaAs cladding layer.
{"title":"An in-depth study on the fabrication of 1055–1064 nm multi-quantum-well and super-lattice laser diodes","authors":"A. Wu, H. Tseng, C. Wan, Yan-Kuin Su, Chenming Hu, S. Tsau","doi":"10.1109/IMPACT.2009.5382170","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382170","url":null,"abstract":"The InGaAs/GaAs multi-quantum-well as well as the AlGaAs/GaAs and the GaAsP/GaAs super-lattice laser diodes were successfully fabricated by low-pressure MOCVD system, and a number of novel structures were explored in this systematic investigation. The strain-relief effect and the composition of cladding layers were analyzed in detail. Via a series of growth experiments, we concluded that better lasing efficiency and the minimum threshold current could be obtained from the sample made up of the AlGaAs/GaAs structure combined with the 60% Aluminum content of the AlGaAs cladding layer.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"45 1","pages":"100-103"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82689985","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382249
K. Hsieh, S. Wong
The performance of a novel vapor chamber is tested in this study. In this vapor chamber, parallel grooves are made on the inner surface of the top plate, with inter-groove openings, to replace the conventional porous wick. To the inner surface of the bottom plate is sintered a layer of porous wick as the evaporator. The peaks of the groove walls directly contact with the wick so that the grooves function as vapor path, condenser and structural supporters simultaneously. The corrugated groove walls provide not only an enlarged condensation area, but also a direct shortcut for a portion of the liquid condensed on the groove surface to be absorbed back to the wick. Thus, smaller liquid-flow resistance and hence high anti-dryout capability are achieved. The test module includes a copper plate-fin heat sink in combination with a top fan. In this study, the evaporator wick was made of sintered multi-layer copper screens and the footprint of the vapor chamber was 10 cm × 8.9 cm. With a 2.1 cm × 2.1 cm or a 1.1 cm × 1.1 cm heating area, the vapor chamber resistances were measured for heat load increasing from 80 W to beyond 300 W. Good performances with low vapor chamber resistance and large heat load limit were obtained under different orientations.
本文对一种新型蒸汽室进行了性能测试。在该蒸汽室中，在顶板的内表面上制作平行凹槽，凹槽间有开口，以取代传统的多孔灯芯。在底板的内表面烧结一层多孔灯芯作为蒸发器。槽壁的峰值与芯直接接触，使槽同时起蒸汽通道、冷凝器和结构支撑的作用。波纹槽壁不仅提供了一个扩大的冷凝面积，而且还提供了一个直接的捷径，使在槽表面冷凝的一部分液体被吸收回芯。因此，液体流动阻力较小，因此具有较高的抗干性。测试模块包括一个铜板翅散热器和一个顶部风扇。在本研究中，蒸发器芯芯由烧结多层铜网制成，蒸汽室占地面积为10 cm × 8.9 cm。在2.1 cm × 2.1 cm或1.1 cm × 1.1 cm的加热区域，测量了热负荷从80w增加到300w以上时的蒸汽室阻力。在不同取向下均获得了较低的气室阻力和较大的热负荷极限。
{"title":"Performance tests on a novel vapor chamber","authors":"K. Hsieh, S. Wong","doi":"10.1109/IMPACT.2009.5382249","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382249","url":null,"abstract":"The performance of a novel vapor chamber is tested in this study. In this vapor chamber, parallel grooves are made on the inner surface of the top plate, with inter-groove openings, to replace the conventional porous wick. To the inner surface of the bottom plate is sintered a layer of porous wick as the evaporator. The peaks of the groove walls directly contact with the wick so that the grooves function as vapor path, condenser and structural supporters simultaneously. The corrugated groove walls provide not only an enlarged condensation area, but also a direct shortcut for a portion of the liquid condensed on the groove surface to be absorbed back to the wick. Thus, smaller liquid-flow resistance and hence high anti-dryout capability are achieved. The test module includes a copper plate-fin heat sink in combination with a top fan. In this study, the evaporator wick was made of sintered multi-layer copper screens and the footprint of the vapor chamber was 10 cm × 8.9 cm. With a 2.1 cm × 2.1 cm or a 1.1 cm × 1.1 cm heating area, the vapor chamber resistances were measured for heat load increasing from 80 W to beyond 300 W. Good performances with low vapor chamber resistance and large heat load limit were obtained under different orientations.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"44 1","pages":"573-576"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84534429","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382166
W. Lee, G. Lin, D. Chang, J. Jiang, Carl Chen
Flux used in 25um ultra fine pitch flip chip attachment process has been found to play an important role in the bump joint and performance. It is commonly used in cleaning the surfaces of solder balls and the surfaces to be soldered to ensure a good wetting of the solder bumps on the substrate pads. Here we use Cu pillar bump with solder cap and substrate pad surface finish is plating tin, and furthermore the standard reflow process was used to perform the evaluation. Due to higher bonding temperature requirement, a Pbfree compatible no clean flux is needed. This kind of flux is formulated to work well with small bump diameter and pitch which have low residual after reflow profile and low weight loss during the whole process. Of course they are achieving compatibility with the underfill. For this new generation flip chip products, how to select a suitable flux is the most challenge. This paper gives a detailed description of the challenges encountered during assembly, such as the flux selection process, flux height study. The characteristics of flux can be determined by using TGA, wet-ability test, and thermal resistance. For ultra fine pitch flip chip application, no clean and low residue flux is the basic demand. Besides, jetting type flux will be the best choice because the flux height is hard to control and the flux amount might not be enough to provide the solder joint ability. Finally, we conclude that the most rigid bonding method, and parameter for fine pitch Cu pillar bump flip chip package.
{"title":"Flux study for ultra fine pitch flip chip packages","authors":"W. Lee, G. Lin, D. Chang, J. Jiang, Carl Chen","doi":"10.1109/IMPACT.2009.5382166","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382166","url":null,"abstract":"Flux used in 25um ultra fine pitch flip chip attachment process has been found to play an important role in the bump joint and performance. It is commonly used in cleaning the surfaces of solder balls and the surfaces to be soldered to ensure a good wetting of the solder bumps on the substrate pads. Here we use Cu pillar bump with solder cap and substrate pad surface finish is plating tin, and furthermore the standard reflow process was used to perform the evaluation. Due to higher bonding temperature requirement, a Pbfree compatible no clean flux is needed. This kind of flux is formulated to work well with small bump diameter and pitch which have low residual after reflow profile and low weight loss during the whole process. Of course they are achieving compatibility with the underfill. For this new generation flip chip products, how to select a suitable flux is the most challenge. This paper gives a detailed description of the challenges encountered during assembly, such as the flux selection process, flux height study. The characteristics of flux can be determined by using TGA, wet-ability test, and thermal resistance. For ultra fine pitch flip chip application, no clean and low residue flux is the basic demand. Besides, jetting type flux will be the best choice because the flux height is hard to control and the flux amount might not be enough to provide the solder joint ability. Finally, we conclude that the most rigid bonding method, and parameter for fine pitch Cu pillar bump flip chip package.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"29 1","pages":"117-120"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84433457","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382135
Tao-Chih Chang, H. Chang, C. Zhan, Jing-Yao Chang, Jiali Fan, J. Chou
A complete halogen-free test vehicle was achieved by assembling five ball grid array (BGA) components with daisy-chain on an 8-layer high density interconnection (HDI) printed circuit board with a low-halide Sn1.0Ag0.5Cu (SAC105) Pb-free solder pastes for reducing the formation of Ag3Sn. Afterward a board-level cyclic bending test was enforced on the as-reflowed assemblies according to the JESD22-B113 standard to evaluate the reliability of HF PCBA under a low-level load condition. The Weibull analyses showed that the characteristic lives of the assemblies were 99,098 and 130,290 cycles on Cu pad and electroless Ni pad, respectively, and the failure mode was the fracture of Cu trace within the micro-via induced by the crack of resin coated copper (RCC) layer. At the interfaces of solder joints, the intermetallic compound (IMC) formed on both Cu and electroless Ni was (Cu, Ni)6Sn5 with various Ni contents of 3.9 and 20.1 at%, respectively, and different thicknesses of 5.6 and 1.1 um. The simulation results pointed out that the factors of composition and thickness of IMC significantly influenced the stress distribution and characteristic life of the HF test vehicle. The stiff (Cu, Ni)6Sn5 constrained the deformation of solder joint interconnection, but increased the stress concentrated on soldering pad and RCC layer. Although the (Cu, Ni)6Sn5 on the electroless Ni was stiffer than that on the Cu pad, the thicker (Cu, Ni)6Sn5 instead increased the stress on the Cu pad due to size effect, and results in a lower characteristic life.
{"title":"Influence of intermetallic compound on the stress distribution and fatigue life of halogen-free printed circuit board assembly","authors":"Tao-Chih Chang, H. Chang, C. Zhan, Jing-Yao Chang, Jiali Fan, J. Chou","doi":"10.1109/IMPACT.2009.5382135","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382135","url":null,"abstract":"A complete halogen-free test vehicle was achieved by assembling five ball grid array (BGA) components with daisy-chain on an 8-layer high density interconnection (HDI) printed circuit board with a low-halide Sn1.0Ag0.5Cu (SAC105) Pb-free solder pastes for reducing the formation of Ag3Sn. Afterward a board-level cyclic bending test was enforced on the as-reflowed assemblies according to the JESD22-B113 standard to evaluate the reliability of HF PCBA under a low-level load condition. The Weibull analyses showed that the characteristic lives of the assemblies were 99,098 and 130,290 cycles on Cu pad and electroless Ni pad, respectively, and the failure mode was the fracture of Cu trace within the micro-via induced by the crack of resin coated copper (RCC) layer. At the interfaces of solder joints, the intermetallic compound (IMC) formed on both Cu and electroless Ni was (Cu, Ni)6Sn5 with various Ni contents of 3.9 and 20.1 at%, respectively, and different thicknesses of 5.6 and 1.1 um. The simulation results pointed out that the factors of composition and thickness of IMC significantly influenced the stress distribution and characteristic life of the HF test vehicle. The stiff (Cu, Ni)6Sn5 constrained the deformation of solder joint interconnection, but increased the stress concentrated on soldering pad and RCC layer. Although the (Cu, Ni)6Sn5 on the electroless Ni was stiffer than that on the Cu pad, the thicker (Cu, Ni)6Sn5 instead increased the stress on the Cu pad due to size effect, and results in a lower characteristic life.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"75 1","pages":"220-223"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83795873","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382272
P. Wei, S. Hsiao
The shapes of a growing or decaying bubble entrapped by a solidification front are predicted in this work. The bubble results from supersaturation of a dissolved gas in the liquid ahead of the solidification front. Pore formation and its shape in solid are one of the most serious issues affecting properties, microstructure, and stresses in materials. In this study, the bubble and pore shapes entrapped in solid are realistically predicted by utilizing perturbation solutions of Young-Laplace equation governing the tiny bubble shape in the literature. The growth and entrapment of a microbubble in solid can be predicted and found to agree with experimental data.
{"title":"Mechanism of pore formation in solid","authors":"P. Wei, S. Hsiao","doi":"10.1109/IMPACT.2009.5382272","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382272","url":null,"abstract":"The shapes of a growing or decaying bubble entrapped by a solidification front are predicted in this work. The bubble results from supersaturation of a dissolved gas in the liquid ahead of the solidification front. Pore formation and its shape in solid are one of the most serious issues affecting properties, microstructure, and stresses in materials. In this study, the bubble and pore shapes entrapped in solid are realistically predicted by utilizing perturbation solutions of Young-Laplace equation governing the tiny bubble shape in the literature. The growth and entrapment of a microbubble in solid can be predicted and found to agree with experimental data.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"69 1","pages":"660-661"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89506536","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382247
Yu-Min Lin, Su-Tsai Lu, Tai-Hong Chen
In this study, three kinds of NCF adhesives named as NCF I, NCF II and NCF III, were applied to COF package with compliant-bump. Firstly, to investigate bonding temperature effects, the curing rate of the NCFs and strength of interconnection under different bonding temperatures (150 °C ∼ 230 °C) were evaluated using differential scanning calorimeter (DSC) test and a 90 degree peeling test, respectively. Then, the electrical performances of NCF joints bonded at different bonding temperatures were monitored by measuring daisy chain and insulated resistance. After that, the reliability tests of 85 °C / 85 % RH thermal humidity storage test (THST), and 55 °C ∼ 125 °C thermal cycling test (TCT) were performed. Finally, the cross-section images of failure samples from SEM were observed to find the failure mode.
{"title":"Reliability of 20µm pitch NCF type COF package with compliant-bump","authors":"Yu-Min Lin, Su-Tsai Lu, Tai-Hong Chen","doi":"10.1109/IMPACT.2009.5382247","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382247","url":null,"abstract":"In this study, three kinds of NCF adhesives named as NCF I, NCF II and NCF III, were applied to COF package with compliant-bump. Firstly, to investigate bonding temperature effects, the curing rate of the NCFs and strength of interconnection under different bonding temperatures (150 °C ∼ 230 °C) were evaluated using differential scanning calorimeter (DSC) test and a 90 degree peeling test, respectively. Then, the electrical performances of NCF joints bonded at different bonding temperatures were monitored by measuring daisy chain and insulated resistance. After that, the reliability tests of 85 °C / 85 % RH thermal humidity storage test (THST), and 55 °C ∼ 125 °C thermal cycling test (TCT) were performed. Finally, the cross-section images of failure samples from SEM were observed to find the failure mode.","PeriodicalId":6410,"journal":{"name":"2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference","volume":"47 1","pages":"568-571"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89664071","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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