Interfacial Reaction and Shear Energy of Sn-52In Solder on Ti/Cu/Au UBM with Variation of Au Thickness and Reflow Temperature

Ti/Cu/Au UBM의 Au 두께와 리플로우 온도에 따른 Sn-52In 솔더와의 계면반응 및 전단 에너지

  • Choi Jae-Hoon (Department of Materials Science and Engineering, Hongik University) ;
  • Jun Sung-Woo (Department of Materials Science and Engineering, Hongik University) ;
  • Oh Tae-Sung (Department of Materials Science and Engineering, Hongik University)
  • 최재훈 (홍익대학교 신소재공학과) ;
  • 전성우 (홍익대학교 신소재공학과) ;
  • 오태성 (홍익대학교 신소재공학과)
  • Published : 2005.03.01

Abstract

Interfacial reactions between 48Sn-52In solder and $0.1{\mu}m$ Ti/3 ${\mu}m$ Cu/Au under bump metallurgies(UBM) with various Au thickness of $0.1{\~}0.7{\mu}m$ have been investigated after solder reflow at $150^{\circ}C,\;200^{\circ}C$, and $250^{\circ}C$ for 1 minute. Ball shear strength and shear energy of the Sn-52In solder bump on each UBM was also evaluated. With reflowing at $150^{\circ}C$ and $200^{\circ}C$, $Cu_6(Sn,In)_5$ and $AuIn_2$ intermetallic compounds were formed at UBW solder interface. However, UBM was consumed almost completely with reflowing at $250^{\circ}C$. While ball shear strength was not consistent with UBM/solder reactions, ball shear energy matched well with UBM/solder reactions.

Au 층의 두께를 $0.1{\~}0.7{\mu}m$로 변화시킨 $0.1{\mu}m$ Ti/3 ${\mu}m$ Cu/Au UBM 상에서 48Sn-52In 솔더를 $150-250^{\circ}C$의 온도 범위에서 리플로우시 UBM/솔더 반응에 의한 금속간화합물의 형성거동을 분석하였다. 또한 Ti/Cu/Au UBM의 Au 두께 및 리플로우 온도에 따른 볼 전단강도와 전단에너지를 분석하였다. $150^{\circ}C$$200^{\circ}C$에서 리플로우 시에는 UBM/솔더 계면에 $Cu_6(Sn,In)_5$$AuIn_2$ 금속간 화합물이 형성되어 있으나, $250^{\circ}C$에서 리플로우 시에는 솔더 반응이 크게 증가하여 UBM이 대부분 소모되었다. 볼 전단강도는 UBM/솔더 반응과 일치하지 않는 결과를 나타내었으나, 전단 에너지는 UBM/솔더 반응과 잘 일치하는 변화 거동을 나타내었다.

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