Partial resist free approach in contact etch to improve W-filling

摘要

A method is provided for improving the tungsten, W-filling of hole openings in semiconductor substrates. This is accomplished by forming an opening-which can be used either as a contact or via hole-with a faceted entrance along with tapered side-walls. This combination of faceted entrance and tapered side-walls improves substantially the tungsten W-filling of contact/via holes in substrates without the formation of key-holes, thereby resulting in metal plugs of high electrical integrity and high reliability.