Patent ID: 6228689
Filing Date: 2001-05-08
Classification: H01L

Abstract:
A method of fabricating a trench style bump, comprising:providing a silicon chip with a metal pad formed thereon, wherein the metal pad covers a part of the silicon chip;forming a passivation layer over an edge of the metal layer and a part of the silicon chip which is not covered by the metal pad, so that a part of the passivation layer swells around the edge of the metal pad;forming an under bump metal over the silicon chip to cover the passivation layer and the metal pad, wherein the under bump material follows a contour of the passivation layer;forming and patterning a first photo-resist layer, so that a first opening aligned with the metal pad is formed, and the under bump material is exposed within the first opening;forming a first bump material layer to fill the first opening;forming and patterning a second photo-resist layer on the first photo-resist layer and the first bump material, so that at least a second opening is formed in the second photo-resist layer to expose a portion of the first bump material;forming a second bump material layer to fill the second opening in the second photo-resist layer;removing the first and the second photo-resist layers, so that the first bump material layer and the second bump material layer are combined as one trench style bump having at least a trench thereon; andremoving a part of the under bump material with the trench style bump as a mask.