PLASMA ETCHING METHOD

摘要

Provided is a plasma etching method comprising: supplying an etching gas including an oxygen gas and a sulfur fluoride gas is supplied at a prescribed flow rate into a process container in which a substrate to be processed is placed, the substrate being comprised of a silicon layer and a resist layer formed on the silicon layer, the resist layer having a prescribed pattern; and etching said silicon layer through said resist layer as a mask by means of the plasma generated from said supplied etching gas. The plasma etching method includes a first step of etching said silicon layer in a state where the flow ratio of the oxygen gas to the sulfur fluoride gas is defined as a first flow ratio, a second step of etching said silicon layer while reducing the flow rate of the oxygen gas such that said flow ratio changes from said first flow ratio to a second flow ratio smaller than said first flow ratio, and a third step of etching said silicon layer in a state where said flow ratio is said second flow ratio.