METHOD OF ETCHING THIN FILM OF MATERIAL CONTAINING POROUS SILICA ACCUMULATED ON SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide an etching method for a dielectric thin film of material containing porous silica being made on a semiconductor substrate capable of preventing or reducing the formation of a microtrench at etching on condition that it keeps high etching speed and seiectivity, and besides capable of controlling the taper angle accurately. SOLUTION: In the method of forming discharge plasma by microwaves or high frequency by introducing gas into a vacuum chamber, and etching the thin film of the material containing porous silica accumulated on the substrate by applying negative bias voltage to the substrate, the etching is performed using the fluoric gas not having double coupling as etching gas.