Method of etching silicon nitride film and method of producing semiconductor device

摘要

Provided is a method of etching a silicon nitride film, which comprises subjecting the silicon nitride film located on copper to dry etching using a mixture of fluorocarbon gas and an inert gas as the reaction gas, the fluorocarbon gas containing CF4 and CHF3 supplied at flow rates in a ratio of 3:7 to 0:1 or contains CF4 and CH2F2 supplied at flow rates in a ratio of 2.5:1 to 0:1, thereby suppressing the formation of copper fluoride.