Press-Fit Whisker and its Growth Contributing Factors-Part I

In this paper, a specially designed method for inspecting and categorizing whiskers in press-fit systems was established. Effect of PTH final hole diameter and pin coating thickness on whisker growth was evaluated. It was found that PTH final hole diameter showed more significant effect on whisker growth than pin coating thickness. The smaller the hole was, the more and longer whiskers grow in the press-fit system. However, thicker coating on pins introduced more scratched residue on annular rings and also could increase the chance of short circuit failure. The tin coating thickness on pins for telecom/datacom applications is recommended to between 0.5 μm and 2.5 μm.