Fabrication method of semiconductor integrated circuit device

摘要

A fabrication method of a semiconductor integrated circuit device using a gas mixture comprising SF6, oxygen and nitrogen as a plasma source gas upon dry etching of a W film, a WNx film and a polycrystal silicon film as a gate electrode material by using a silicon nitride film as a mask, the fabrication method capable of ensuring the shape of the gate electrode upon etching fabrication of a gate electrode of a polymetal structure and improving the etching selectivity to the etching stopper film comprising silicon nitride.