PLASMA ETCHING METHOD, PLASMA ETCHING APPARATUS, AND COMPUTER-READABLE STORAGE MEDIUM

摘要

A plasma etching method includes the step of performing a plasma etching on a SiCN layer, which is formed on a substrate to be processed having a SiOCH layer and the SiCN layer, by using a plasma of an etching gas. A gaseous mixture including CF₄ and NF₃ is employed as the etching gas, and the SiCN layer is selectively etched against the SiOCH layer. In the plasma etching method, a selectivity of the SiCN layer against the SiOCH layer (an etching rate of the SiCN layer/an etching rate of the SiOCH layer) is equal to or greater than about 1.1 and a flow rate ratio of the NF₃ to the CF₄ is equal to or greater than about 6%.