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Indexed by:会议论文

Date of Publication:2012-01-01

Included Journals:CPCI-S

Page Number:1403-1406

Abstract:The relationships between the morphology of Ag3Sn phases and the cooling rate, solder volume and 0.7 wt.% Cu addition into Sn-3.5Ag solder were investigated in this study. The morphology of Ag3Sn phases in the solder joints was greatly affected by the cooling rate. In Sn-3.5Ag/ENEPIG (electroless nickel electroless podium immersion gold) solder joints, large plate-like Ag3Sn phases formed on the interfacial intermetallic compounds (lMCs) under furnace cooling, normal cooling and air cooling conditions, while no plate-like Ag3Sn phases formed under water cooling condition. The volume of solder ball also had a significant effect on the morphology of Ag3Sn phases in the solder joints. Large plate-like Ag3Sn phases formed at the Sn-3.5Ag (50 mu m)/ENEPIG (40 mu m) and Sn-3.5Ag (100 mu m)/ENEPIG (150 mu m) interfaces under furnace cooling condition. However, no plate-like Ag3Sn phases were detected at the Sn-3.5Ag (200 mu m)/PIG (150 mu m) interface under the same cooling condition. The degree of undercooling increased with downsizing solder joints, which would extend the growth time of Ag3Sn phases in the solidification process. The addition of 0.7 wt.% Cu into Sn-3.5Ag solder had little effect on the morphology of Ag3Sn phases in the solder joints.