ETCHING METHOD FOR FILM TO BE ETCHED, AND MANUFACTURING METHOD FOR SEMICONDUCTOR DEVICE TO WHICH THE SAME IS APPLIED

摘要

PROBLEM TO BE SOLVED: To provide an etching method with high flexibility in which a taper angle of a side surface can easily and stably be controlled when a film to be etched is subjected to wet etching. Ž

SOLUTION: In the etching method, before an oxide film 2 is wet-etched using a photoresist film 3, formed on a silicon oxide film (a film to be etched) 2 as a thermal oxide film formed on a silicon substrate 1, as a mask, the resist film 3 and oxide film 2 are irradiated with a suitable quantity of ultraviolet rays UV to reinforce adhesiveness of an inter-film interface, and an etchant prepared by mixing an undiluted solution (50 wt.% HF) and an undiluted solution (40 wt.% NH4F) in 1:20 proportion is used for the wet etching to determine a taper angle θ of a side face of the oxide film 2. The taper angle θ is varied depending upon the adhesiveness of the inter-film interface varying with the irradiation time of the ultraviolet rays UV, so the irradiation time of the ultraviolet rays UV is suitably determined according to requested product specifications to control the taper angle θ of the oxide film 2. Ž

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