Patent ID: 6784089
Filing Date: 2004-08-31
Classification: H01L

Abstract:
A method of making an electrical contact bump structure on a substrate comprising:providing a substrate having a bond pad, and a passivation layer overlying a portion of the substrate and wherein the passivation layer includes an opening therein exposing a portion of the bond pad, and wherein the passivation layer has a raised portion overlying the bond pad; forming an under bump metallurgy at least over the exposed portion of the bond pad and over at least a portion of the raised portion of the passivation layer overlying the bond pad; forming a sacrificial blanket having an opening therein that in cross-section has an inverted T-shape over the substrate so that the opening in the sacrificial blanket is aligned with the bond pad; depositing an electrically conductive material into the opening in the sacrificial blanket so that the electrically conductive material overlie at least a portion of the under bump metallurgy including the portion of the under bump metallurgy overlying the raised portion of the passivation layer and so that a bump structure is formed having a flat-top engagement surface that is free of any raised portion.