The Destruction Mode and the Life Cycle Times of the Chip Size Package Mounted on the Circuit Board by the Bending Test

Abstract

The requirement of high-density packaging has becoming strongly in the portable electronic products with progressing for miniature, lightweight, high speed, and high function. The use of the miniature semiconductor package, such as Chip Size Package, has been growing very rapidly. The portable products are subjected to mechanical stress as it is pressed keypad and it is dropped. Therefore mechanical reliability is very important in the portable products. Then, we have performed with the repeatedly bending test of the CSP mounted on the circuit board. As a result, the first failures occurred in the CSP's corner pads. And the correlation between the life cycle times and the destruction mode was made clear. It was found out that a exfoliation between solder and PWB's pad, and a broken wire of PWB were occurred earlier than the solder crack in case of comparing Sn-Ag-Cu solder with Sn-Pb eutectic solder. It was found out that the life cycle of the Sn-Ag-Cu solder was better than that of the Sn-Pb eutectic solder.