Patent ID: 7189646
Filing Date: 2007-03-13
Classification: H01L

Abstract:
1. A bumping process, comprising: providing a wafer having a plurality of bonding pads and a passivation layer that exposes the bonding pads; forming a metallic layer over the bonding pad wherein a portion of the passivation layer is exposed by the metallic layer; forming a first photoresist layer over the wafer; forming a second photoresist layer over the first photoresist layer; wherein the first photoresist layer has a viscosity smaller than the second photoresist layer; performing an exposure and development process to form a plurality of openings in the first and the second photoresist layer, wherein the openings expose the metallic layer; filling a solder material into the openings to form a plurality of solder posts; and removing the first photoresist layer and the second photoresist layer.