• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.203-205
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• 2003

레이저 다이오드를 p-side-down 방식으로 본딩하기 위하여 AuSn 솔더합금을 증착한 후 온도와 압력, 시간을 변화시켜 본딩상태를 조사하였다. CuW위에 adhsion layer와 확산방지층을 각각 $500{\AA}$과 $2000{\AA}$을 증착하였으며 솔더층으로 AuSn을 $2.6{\mu}m$ 증착 하였다. 열처리는 질소 분위기에서 행하였으며, 표면의 거칠기는 AFM으로 측정하였다.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.82-85
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• 2012

The effect of the alloy systems Al-Mg alloy and Al-Si alloy in this study on the characteristics of die-casting were investigated using solidification simulation software (MAGMAsoft). Generally, it is well known that the casting characteristics of Al-Mg based alloys, such as the fluidity, feedability and die soldering behaviors, are inferior to those of Al-Si based alloys. However, the simulation results of this study showed that the filling pattern behaviors of both the Al-Mg and Al-Si alloys were found to be very similar, whereas the Al-Mg alloy had higher residual stress and greater distortion as generated due to solidification with a larger amount of volumetric shrinkage compared to the Al-Si alloy. The Al-Mg alloy exhibited very high relative numbers of stress-concentrated regions, especially near the rib areas. Owing to the residual stress and distortion, defects were evident in the Al-Mg alloy in the areas predicted by the simulation. However, there were no visible defects observed in the Al-Si alloy. This suggests that an adequate die temperature and casting process optimization are necessary to control and minimize defects when die casting the Al-Mg alloy. A Tatur test was conducted to observe the shrinkage characteristics of the aluminum alloys. The result showed that hot tearing or hot cracking occurred during the solidification of the Al-Mg alloy due to the large amount of shrinkage.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.131-137
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• 1999

Package crack caused by the soldering process in the surface mounting plastic package is evaluated by applying the energy release rate criterion. The package crack formation depend on various parameters such as chip set, chip size, package thickness, package width, material properties and the moisture content etc. The effects of chip set and the other parameters were estimated during the analysis of package cracks which were located in the edge of the upper interface of the chip and the lower interlace of the die pad. From the results, it could be obtained that the more significant parameters to effect the chip set are chip width.

• Korean Journal of Metals and Materials
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• v.50 no.10
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• pp.775-783
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• 2012

The effect of thermal annealing on the in-situ growth characteristics of intermetallics (IMCs) and the mechanical strength of Cu pillar/Sn-3.5Ag microbumps are systematically investigated. The $Cu_6Sn_5$ phase formed at the Cu/solder interface right after bonding and grew with increased annealing time, while the $Cu_3Sn$ phase formed at the $Cu/Cu_6Sn_5$ interface and grew with increased annealing time. IMC growth followed a linear relationship with the square root of the annealing time due to a diffusion-controlled mechanism. The shear strength measured by the die shear test monotonically increased with annealing time. It then changed the slope with further annealing, which correlated with the change in fracture modes from ductile to brittle at a critical transition time. This is ascribed not only to the increasing thickness of brittle IMCs but also to the decreasing thickness of the solder, as there exists a critical annealing time for a fracture mode transition in our thin solder-capped Cu pillar microbump structures.