BGA 무연솔더(Sn-3.0Ag-0.5Cu)와 무전해 Ni-W-P 도금층 계면의 열 안정성에 대한 연구

Study on Thermal Stability of the Interface between Electroless Ni-W-P Deposits and BGA Lead-Free Solder (Sn-3.0Ag-0.5Cu)

  • 신동희 (한국산업기술대학교 신소재공학과) ;
  • 조진기 (한국산업기술대학교 신소재공학과) ;
  • 강성군 (한양대학교 신소재공학부)
  • Shin, Dong-Hee (Department of the Advenced Materials Engineering, Korea Polytechnic University) ;
  • Cho, Jin-Ki (Department of the Advenced Materials Engineering, Korea Polytechnic University) ;
  • Kang, Seung-Goon (Division of Materials Science Engineering, Hanyang University)
  • 투고 : 2009.12.17
  • 심사 : 2010.03.16
  • 발행 : 2010.03.30

초록

본 연구에서는 무연 솔더 중 우수한 특성을 보여 실용화된 Sn-3.0Ag-0.5Cu 조성의 솔더를 사용하여 2주 동안의 시효조건에서 W의 함량이 무전해 Ni-W-P 도금층과 솔더와의 계면에서의 IMC 생성에 미치는 영향에 대해서 조사하였다. 도금층내 인의 함량은 8 wt.%로 고정하였고, 텅스텐의 함량은 각각 0, 3, 6 및 9 wt.%로 변화시켰으며, 모든 시료는 $255^{\circ}C$에서 리플로우한 후, $200^{\circ}C$에서 2주 동안 시효처리하였다. 각각의 시료에서 $(Cu,Ni)_6Sn_5$$(Ni,Cu)_3Sn_4$의 IMC가 관찰되었으며, 시효처리시간의 증가에 따라 UBM과 무연납의 계면에서 생성된 IMC가 증가함을 보였고, W의 함량이 높을수록 열적 안정성이 증가하여 $Ni(W)_3P$의 생성 속도를 늦춰 그에 따른 영향으로 IMC의 두께가 증가함을 보였다.

In this study, we investigated the morphology and thermal stability of interfacial phases in joint between lead free solder(Sn-3.0Ag-0.5Cu) and electroless Ni-W-P under bump metallizations(UBM) with different tungsten contents as a function of thermal aging. Content of phosphorus of each deposits was fixed at 8 wt.%, and content of tungsten was variated each 0, 3, 6 and 9 wt.%. Specimens were prepared by reflowing at $255^{\circ}C$, aging range was $200^{\circ}C$ and up to 2 weeks. After reflow process, in the electroless Ni(W)-P/solder joint, the interfacial intermetallic compound(IMC) was showed both $(Cu,Ni)_6Sn_5$ and $(Ni,Cu)_3Sn_4$. UBM and generated IMC at the interface of lead free solder was proportionally increased with aging time. The thickness of IMC was increased because the generation rate of $Ni(W)_3P$ decreased with increasing contents of W.

키워드

참고문헌

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