• Proceedings of the KWS Conference
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• 2007.11a
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• pp.215-217
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• 2007

철계 피삭재 가공 시 적용되는 cBN(cubic Boron-Nitride)의 경우 열적/구조적 안정성으로 인해 융착 시 계면에서 화학적 결합이 어려워, 지립이 단일층으로 형성되어야 하는 융착 공구의 경우 적용되질 못하고 있다. 이러한 문제를 해결하기 위해 세라믹과의 젖음성이 우수한 Ti 성분이 포함된 67Ag+28Cu+5Ti(wt.%) 조성의 합금분말을 이용하여 cBN을 접합을 하였으며, 이때 융착조건은 진공 분위기($6{\times}10^{-6}$Torr), $900^{\circ}C$ 온도에서 5분간 유지하여 융착을 실시하였다. 본 연구의 주목적은 Ti 합금화 된 Ag계 합금분말 및 cBN의 융착 계면에서의 융착 계면거동해석을 통한 건전한 접합공정을 찾는데 있다. 이에 온도 $900^{\circ}C$, 유지시간 5분에서 건전한 융착층을 형성함을 알 수 있었다. 또한 결합력 측정기를 이용하여 결합력을 측정한 결과 diamond와 융착하였을 때가 123N, cBN을 융착하였을 때 107N으로써, cBN 융착이 diamond 융착의 87%정도의 결합력을 보임을 알 수 있었다. 한편 cBN과 Ag-Cu-Ti계 브레이징 필러의 계면에서의 미세조직 및 화학반응의 메커니즘은 SEM, EDS를 이용하여 분석하였다.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.61-66
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• 2010

Cu-Cu thermo-compression bonding process was successfully developed as functions of the deposited Cu thickness and $Ar+H_2$ forming gas annealing conditions before and after bonding step in order to find the low temperature bonding conditions of 3-D integrated technology where the interfacial toughness was measured by 4-point bending test. Pre-annealing with $Ar+H_2$ gas at $300^{\circ}C$ is effective to achieve enough interfacial adhesion energy irrespective of Cu film thickness. Successful Cu-Cu bonding process achieved in this study results in delamination at $Ta/SiO_2$ interface rather than Cu/Cu interface.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.81-88
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• 2019

In this study, the effects of graphene oxide (GO) addition on electromigration (EM) lifetime of Sn-3.0Ag-0.5Cu Pb-free solder joint between a ball grid array (BGA) package and printed circuit board (PCB) were investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of package side finished with electroplated Ni/Au, while $Cu_6Sn_5$ IMC was formed at the interface of OSP-treated PCB side. Mean time to failure of solder joint without GO solder joint under $130^{\circ}C$ with a current density of $1.0{\times}10^3A/cm^2$ was 189.9 hrs and that with GO was 367.1 hrs. EM open failure was occurred at the interface of PCB side with smaller pad diameter than that of package side due to Cu consumption by electrons flow. Meanwhile, we observed that the added GO was distributed at the interface between $Cu_6Sn_5$ IMC and solder. Therefore, we assumed that EM reliability of solder joint with GO was superior to that of without GO by suppressing the Cu diffusion at current crowding regions.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.245.1-245
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• 2001

• Composites Research
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• v.13 no.4
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• pp.67-74
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• 2000

The general solution of the anti-plane shear problem for the curved interfacial crack between viscoelastic foam and composites was investigated with the complex variable displacement function. Kelvin-Maxwell three parameter model is used to present viscoelasticity and the Laplace transform was applied to treat the viscoelastic characteristics of foam in the analysis. The stress intensity factor near the interfacial crack tip was predicted by considering both anisotropic and viscoelastic properties of two different materials. The results showed that the stress intensity factor increased with increasing the curvature of the curved interfacial crack and it also increased and eventually converged to a specific value with increasing time. The stress intensity factor increased with increasing the ratio of stiffness coefficients between foam and composites and the effect of fiber orientation on the stress intensity factor decreased with increasing the ratio of stiffness coefficients between foam and composites.

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.102-105
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• 2000

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.193-196
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• 2000

• Proceedings of the KWS Conference
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• 2000.10a
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• pp.281-283
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• 2000

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.77-79
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• 2003

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.75-78
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• 1994