کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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544457 | 1450392 | 2012 | 5 صفحه PDF | دانلود رایگان |
An investigation of the effects of thermal annealing on the growth of intermetallic compounds (IMCs) and the shear strength of Cu/Sn/Cu pillar bump structures is presented. The Cu6Sn5 phase formed at the Cu/Sn interface right after bonding and grew as with annealing time, while the Cu3Sn phase formed and grew at the Cu/Cu6Sn5 interface 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 was measured by the lap shear test and was observed to monotonically decrease with annealing until 150 h at 150 °C. It then stayed nearly constant with further annealing, which is correlated with the change in fracture modes from ductile to brittle at around the 150 h mark. This is ascribed not only to the increasing thickness of brittle IMCs but also to the decreasing thickness of Sn, as there exists a critical annealing time for a fracture mode transition in our thinly Sn-capped Cu pillar bump structures.
Journal: Microelectronic Engineering - Volume 89, January 2012, Pages 65–69