Method of fabricating seamless tungsten plug employing tungsten redeposition and etch back

摘要

A process has been developed in which seamless tungsten plugs are used to fill deep, narrow contact holes. The process features initially forming a tungsten plug in a contact hole, via tungsten LPCVD processing, followed by an RIE etch back, and recessing process. A second tungsten LPCVD procedure is then used to fill seams or defects in the underlying tungsten plug. Another RIE etch back procedure is then employed to create a seamless, composite tungsten plug structure, in the deep, narrow contact hole.