3차원 칩 적층을 위한 Cu pillar/Sn-3.5Ag 미세범프 접합부의 금속간화합물 성장거동에 따른 전단강도 평가 (Effect of Intermetallic Compounds Growth Characteristics on the Shear Strength of Cu pillar/Sn-3.5Ag Microbump for a 3-D Stacked IC Package)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 50권 / 10호 / 775 ~ 783페이지
· 저자명 : 곽병현, 정명혁, 박영배

초록

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 Cu6Sn5phase formed at the Cu/solder interface right after bonding and grew with increased annealing time, while the Cu3Sn phase formed at the Cu/Cu6Sn5 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.

영어초록

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 Cu6Sn5phase formed at the Cu/solder interface right after bonding and grew with increased annealing time, while the Cu3Sn phase formed at the Cu/Cu6Sn5 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.

참고자료

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