EFFECTS OF THE COOLING RATE ON THE MECHANICAL AND ELECTRICAL BEHAVIOR OF A 63SN/37PB SOLDER BUMP ON A METALLIZED SI SUBSTRATE

Abstract

Flip-chip bonding technology, with solder bumps deposited on metal terminals on the chip, provides the highest functional densities of all the present bonding techniques. In this study, tin-lead solder bumps were screen printed onto a metallized Si substrate. Various cooling rates were employed after reflowing the solder bumps. The effect of the cooling rate on the microhardness, the adhesion strength and the electrical resistance of solder joints was studied and the mechanism explored. It was found that intermetallic compounds play important roles in both the mechanical and the electrical behaviour of the solder bumps.