Patent ID: 6232212
Filing Date: 2001-05-15
Classification: H01L

Abstract:
A process for bonding an IC chip to a support substrate, said IC chip having a a plurality of aluminum bonding sites and a capping layer surrounding the plurality of aluminum bonding sites, comprising the steps of:(a) selectively applying under bump metallization (UBM) to the aluminum bonding sites, leaving portions of the capping layer exposed,(b) forming a buffer layer directly on the said portions of the capping layer,(c) forming a photoresist mask on said buffer layer, said photoresist mask having open portions thereof exposing said UBM,(d) filling said open portions of the photoresist mask with solder paste,(e) heating said solder paste to reflow the solder paste and form solder bumps on said UBM,(f) removing said photoresist mask, and(g) removing said buffer layer.