Method for etching aluminum metal films

摘要

A mixed etching gas consisting of boron trichloride, a rare gas, and chlorine is used for etching of an aluminum metal film by dry-etching. In the first step, high frequency power is used to etch and remove alloy grains which tend to form residues and to etch an aluminum metal film in an anisotropic mode. Just before the under-layered silicon film is exposed, the frequency power is lowered but is kept higher than the minimum power required for anisotropic etching to enable etching selectivity with respect to the silicon dioxide film to be achieved.