Copper post structure for wafer level chip scale package

摘要

In a method for forming a packaging structure, a metal pad is formed on a semiconductor substrate, and a first polymer insulating layer is formed over the semiconductor substrate. An opening passing through the first polymer insulating layer is formed to expose a portion of the metal pad. A copper-containing material is deposited in the opening and over the first polymer insulating layer, thereby forming a copper-containing layer having a first thickness and a first width over the first polymer insulating layer. A conductive bump having a second width is formed over the copper-containing layer, in which the second width is smaller than the first width. An exposed portion of the copper-containing layer is etched using the conductive bump as a mask until the exposed portion is reduced to a second thickness, thereby forming a monolithic copper-containing structure.

主权项

1. A method, comprising:
depositing a copper-containing material over the semiconductor substrate, thereby forming a copper-containing layer having a first thickness and a first width over the semiconductor substrate; forming a conductive bump having a second width over the copper-containing layer, wherein the second width is smaller than the first width; and etching an exposed portion of the copper-containing layer using the conductive bump as a mask until the exposed portion is reduced to a second thickness, thereby forming a monolithic copper-containing structure comprising a top portion and a bottom portion adjoining the top portion, the top portion having a third thickness which is equal to the first thickness minus the second thickness, the bottom portion having the second thickness.