Method for forming an integrated circuit

摘要

A method for forming void free tungsten plug contacts (56a-56c) begins by etching a contact opening (55a-55c) using a C2F6 and CHF3 chemistry. The etch chemistry is then changed to an O2 and CH3F chemistry in order to insitu remove the contact photoresist while tapering an upper portion of the contact opening. A tungsten deposition process is then performed whereby the tapered portion of the contact reduces the effects of nonconformal and step-coverage-inconsistent tungsten deposition wherein voids in the contact are either substantially reduced or totally avoided within the contact structure. The reduction of or total elimination of voids (22) within the tungsten contact will increase yield, increase reliability, and reduce electromigration failures within integrated circuit devices.