Process to minimize a seam in tungsten filled contact holes

摘要

A process has been developed in which high aspect ratio contact holes, are filled with chemically vapor deposited tungsten plugs, exhibiting little or no seam at the center of the tungsten plug. The process features protection of the tungsten plug from the final removal and overetch steps, needed to remove residual tungsten from areas outside the contact hole. This is accomplished by delaying the residual removal procedure, until the tungsten plug is protected by an overlying interconnect metallization structure.