通过作者查论文: Jong Woong Kim

文章题目页数

作者: Jong Woong Kim, Sun Kyu Park, Seung Boo Jung
摘要: Ball shear test was investigated in terms of effects of important test parameters, i.e. shear height and shear speed, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. A Pb-free solder composition was examined in this work: Sn-3Ag-6Bi-2In. The substrate was a common SMD (Solder Mask Defined) type with solder bond pad openings of 460㎛ in diameter. It could be observed that increasing shear height, at fixed shear speed, has the effect of decreasing shear force, while the shear force increased with increasing shear speed at fixed shear height. Too high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial failures or the degraded layers in the interfaces.
851
作者: Jong Woong Kim, Hyun Suk Chun, Sang Su Ha, Jong Hyuck Chae, Jin Ho Joo, Young Eui Shin, Seung Boo Jung
摘要: Board-level reliability of conventional Sn-37Pb and Pb-free Sn-3.0Ag-0.5Cu solder joints was evaluated using thermal shock testing. In the microstructural investigation of the solder joints, the formation of Cu6Sn5 intermetallic compound (IMC) layer was observed between both solders and Cu lead frame, but any crack or newly introduced defect cannot be found even after 2000 cycles of thermal shocks. Shear test of the multi layer ceramic capacitor (MLCC) joints were also conducted to investigate the effect of microstructural variations on the bonding strength of the solder joints. Shear forces of the both solder joints decreased with increasing thermal shock cycles. The reason to the decrease in shear force was discussed with fracture surfaces of the shear tested solder joints.
633
作者: Jong Woong Kim, Seung Boo Jung
摘要: The effects of void formation on the joint strength and failure mode of the solder joints were examined. A computational modeling technique, i.e., finite element modeling, was employed to investigate the effects. The effects of location, size and number of void were also investigated and compared with the case that has no void in the solder ball. When there was 1 or more voids in the solder ball, the joint strength decreased regardless of the location, size, and number of voids. Especially, the shear force of the joints decreased about 50% when 3 voids were formed in the solder ball. From the stress analyses, the possibility of preliminary brittle interfacial failure should be lower when voids were formed in the solder ball.
546
作者: Jong Woong Kim, Jeong Won Yoon, Seung Boo Jung
摘要: The experimental investigation and non-linear finite element analysis using elastic-viscoplastic constitutive model were conducted to study the effect of ball shear speed on shear force of BGA solder joints. The Ag3Sn intermetallic compound (IMC) particles were found inside the Sn-3.5Ag solder, while the fine intermixed structure of lead-rich phases and tin-rich phases was investigated inside the eutectic Sn-37Pb solder. The shear force linearly increased with shear speed and reached to the maximum value at the highest shear speed in both experimental and computational results. All of the test specimens were fractured like ductile mode, and the plastic strain energy density distributions were deeply related to the failure mechanism.
897
作者: Dae Gon Kim, Hyung Sun Jang, Jong Woong Kim, Seung Boo Jung
摘要: In the present work, we investigated the interfacial reactions and shear properties between Sn-3.0Ag-0.5Cu flip chip solder bump and Cu UBM after multiple reflows. The quantitative analyses of the intermetallic compound layer thickness as a function of the number of reflows were performed. After six reflows, the reaction product could be distinguished by two intermetallic compounds: Cu3Sn adjacent to the substrate and Cu6Sn5 which was the dominant phase. The thickness of total intermetallic compound layers increased with the number of reflows. The shear strength value did not significantly change as a function of the number of reflows. Nearly all of the test specimens showed ductile failure mode, and this could be well explained with the results of FEM analyses.
863
作者: Jong Woong Kim, Sun Kyu Park, Seung Boo Jung
摘要: Ball shear test was investigated in terms of the effects of important test parameter, i.e., shear height, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. The substrate was a common SMD type with solder bond pad openings of 460 ㎛ in diameter. It was observed that increasing the shear height, at a fixed shear speed, has the effect of decreasing the shear force. The high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial fractures or the degraded layers in the interfaces.
269
作者: Dae Gon Kim, Jong Woong Kim, Sang Su Ha, Ja Myeong Koo, Bo In Noh, Seung Boo Jung
摘要: Thermo-mechanical reliability of the solder bumped flip chip packages having underfill encapsulant was evaluated with thermal shock testing. In the initial reaction, the reaction product between the solder and Cu mini bump of chip side was Cu6Sn5 IMC layer, while the two phases which were (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 were formed between the solder and electroless Ni-P layer of the package side. A crack was formed at the upper edge region of solder bump, and propagated through the solder region. The primary failure mechanism of the solder joints in this type of package was confirmed to be thermally activated solder fatigue failure. After thermal shocks of 2000 cycles, one more crack which was not observed in the case of non-underfill encapsulated flip chip was observed at the left side of interface between solder bump and substrate. The addition of this crack formation should be due to the underfill encapsulation between the Si chip and substrate.
621
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