METHOD OF ETCHING SILICON SUBSTRATE AND ETCHING APPARATUS THEREFOR

摘要

A method of etching a silicon substrate, which ensures high etching rate and can provide an etching structure excelling in wall surface smoothness and perpendicularity. The etching is accomplished by sequentially repeating the step of while applying bias potential to a silicon substrate through application of firm power thereto, progressing a dry etching mainly on etching ground with the use of a mixture of SF6 gas and fluorocarbon gas and the step of forming a protective film mainly on a structure surface perpendicular to etching ground with the use of the above-mentioned mixed gas. The mixed gas for use in the step of dry etching progress is one consisting of 100 vol. of SF6 gas and 5 to 12 vol. of fluorocarbon gas. The mixed gas for use in the step of protective film formation is one consisting of 2 to 5 vol. of SF6 gas and 100 vol. of fluorocarbon gas.