Solder joints in electronic packaging are being miniaturized year by year. The strength of such a miniaturized solder joint is affected by the presence of Cu/Sn intermetallic compounds (IMCs) generated at the interface between solder and copper wiring. Then, the strength reliability of miniaturized solder joint should be evaluated by the test using a solder joint specimen which contains the IMCs layer. In this study, a joint specimen was prepared by soldering two copper plates with Sn-3.0Ag-0.5Cu (SAC) solder. The IMCs layer was observed between the copper and the SAC solder in the joint part. Using the specimen, we conducted shear tests under four different strain rates. The results showed that the strain rate affected both the stress-strain relation and the cracking tendency of the specimen. Namely, the stress level of the stress-strain relation increased with increase in the strain rate. The cracking in the IMCs layer occurred in smaller deformation stage with increase in the strain rate.
