Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference (한국전기전자재료학회:학술대회논문집)

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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A Study on Bumping of Micoro-Solder for Optical Packaging and Reaction at Solder/UBM interface

광패키징용 마이크로 솔더범프의 형성과 Contact Pad용 UBM간의 계면 반응 특성에 관한 연구

  • 박종환 (홍익대학교 신소재공학과) ;
  • 이종현 (한국전자통신연구원 광모듈패키징팀) ;
  • 김용석 (홍익대학교 신소재공학과)
  • Published : 2001.11.08
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Abstract

In this study, the reaction at UBM(Under Bump Metallurgy) and solder interface was investigated. The UBM employed in conventional optical packages, Au/Pt/Ti layer, were found to dissolve into molten Au-Sn eutectic solder during reflow soldering. Therefore, the reaction with different diffusion barrier layer such as Fe, Co, Ni were investigated to replace the conventional Pt layer. The reaction behavior was investigated by reflowing the solder on the pad of the metals defined by Cr layer for 1, 2, 3, 4, and 5 minutes at $330^{\circ}C$. Among the metals, Co was found to be most suitable for the diffusion barrier layer as the wettability with the solder was reasonable and the reaction rate of intermetallic formation at the interface is relatively slow.

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