Method of reducing voiding in copper interconnects with copper alloys in the seed layer

摘要

A method for forming a copper interconnect with improved via integrity and elimination of via voiding employs a copper seed layer having an alloy element within the seed layer. The alloy element increases the resistance of the copper seed layer to acidic plating chemistry as the vias are filled and as the pulse-reverse wave form is initiated in the electrochemical plating process. The prevention of void formations at the bottom of the via improves the copper filling, with resulting improved electromigration performance, reduced via resistance and improved product speed.