Patent ID: 7250362
Filing Date: 2007-07-31
Classification: H01L

Abstract:
1. A method for forming a solder bump structure, comprising: providing a wafer having at least one metal bonding pad and a passivation layer thereon, wherein the passivation layer leaves the bonding pad exposed; forming an under ball metallurgy layer on the metal bonding pad; successively forming a dielectric layer and a resist layer on the passivation layer, wherein the dielectric layer has a first opening to expose the under ball metallurgy layer and the resist layer a second opening over the first opening; filling the first and second openings with a conductive layer by a printing process; forming a solder bump on the under ball metallurgy layer in the first and second openings by performing a reflow process on the conductive layer, during which the dielectric layer and the resist layer support the conductive layer and prevent from collapse; and removing the resist layer after the reflow process, such that the solder bump is substantially surrounded by the dielectric layer.