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Indexed by:会议论文

Date of Publication:2010-01-01

Included Journals:EI、CPCI-S、Scopus

Page Number:299-304

Abstract:This study focused on the effect of solder volume on the interfacial reaction between Sn3.5Ag0.75Cu solder balls and Cu pads on PCB after various reflow soldering times. The diameters of the solder balls were 200, 300, 400 and 500 mu m, respectively, and the opening diameter of the Cu pads was 250 mu m. The solder volume ratio for the 200, 300, 400 and 500 mu m balls was approximately 1:4:8:16. The interfacial intermetallic compound (IMC) was common scallop-type Cu6Sn5. The thickness of the interfacial Cu6Sn5 IMC layer was obviously thicker for the smaller solder ball after the same reflowing times from 1 to 5. After the first reflow, the thickness of the interfacial Cu6Sn5 IMC layer for the 200 mu m solder ball was 4.39 mu m compared to that of 3.15 mu m for the 500 mu m solder ball. The average diameter of the interfacial Cu6Sn5 grains for the smaller solder ball was significantly larger than that for the bigger one after the same reflowing times from 1 to 5. After the first reflow, the average diameter of the interfacial Cu6Sn5 grains for the 200 mu m solder ball was 5.23 mu m compared to that of 4.22 mu m for the 500 mu m solder ball. Both the thickness of the Cu6Sn5 IMC layer and the average diameter of the interfacial Cu6Sn5 grains increased with the increasing reflow time. The ratios of the average diameter of Cu6Sn5 grains to the thickness of the interfacial Cu6Sn5 IMC layer for all the four kinds of solder balls varied from 1 to 1.5, which showed a vivid growth of the interfacial Cu6Sn5 grains from the perspective of 3 dimensions. Based on the data from the experiment, the dissolution kinetics of the Cu pad can be simulated.