Process flow to optimize profile of ultra small size photo resist free contact

摘要

A new processing sequence is provided for the creation of openings in layers of dielectric. Over a semiconductor surface are successively deposited an etch stop layer, a layer of dielectric and a hard mask layer. An opening is etched in the hard mask layer, the main opening is etched through the layer of dielectric and the etch stop layer. The surface is wet cleaned, after which a thin layer of silicon oxide is CVD deposited over the inside surfaces of the created opening. This thin layer of CVD oxide is subjected to argon sputter, providing of the critical dimensions of the upper region of the opening. Then the process continues with the deposition of the barrier metal, the filling of the opening with a conducting material to create the metal plug and the polishing of the surface of the deposited conducting material.