Structure and method for low resistance interconnections

摘要

A method of forming an interconnection in a semiconductor device includes forming a first liner in a dielectric layer therein; depositing a tungsten filler on top of the first liner; performing chemical mechanical planarization (CMP) to smooth out and remove the first liner and tungsten filler from the semiconductor's exposed surface; selectively removing the first liner and tungsten filler in the via; wherein the selective removing results in the first liner and the tungsten filler being removed in an upper region of the via; forming a second liner in the upper region of the via and tungsten filler; selectively removing the second liner from the tungsten filler; forming a copper seed layer on top of the tungsten filler; depositing a copper filler on top of the copper seed layer; and performing chemical CMP to smooth out and remove the second liner and copper filler from the semiconductor's exposed surface.