Patent ID: 6583039
Filing Date: 2003-06-24
Classification: H01L

Abstract:
A method of forming a bump overlying a copper based contact pad to prevent oxidation of the copper based contact pad comprising:depositing a passivation blanket over a semiconductor device having a copper based contact pad, and wherein the passivation blanket includes a first layer overlying a top surface of the semiconductor device and at least a second layer overlying the first layer; removing a portion of the second layer overlying the copper based contact pad leaving the first layer in place to prevent oxidation of the copper based contact pad; immediately prior to depositing an under bump metallurgy over the semiconductor device, removing a portion of the first layer overlying the copper based contact pad so that the copper based contact pad has limited exposure to oxygen, and wherein the removing of the portion of the first layer overlying the copper based contact pad comprises ion milling the portion of the first layer; depositing an under bump metallurgy over the semiconductor device, and wherein the depositing of the under bump metallurgy over the semiconductor device comprises sputtering under bump material over the semiconductor device; removing excess under bump metallurgy from the semiconductor device leaving the under bump metallurgy overlying the copper based contact pad; depositing an electrically conductive material over the under bump metallurgy that overlies the copper based contact pad; and reflowing the electrically conductive material to form a bump overlying the copper based contact pad.