Method of etching semiconductor substrate

Abstract

A method of performing anisotropic etching more than once with respect to a semiconductor substrate (1) is provided with the steps of performing first-time anisotropic etching by using a first etching mask (2) so as to form a first anisotropically etched region (4) which is hollow, forming a second etching mask (7) over the first etching mask (2), performing second-time anisotropic etching by using the second etching mask (7), and previously forming the first etching mask (2) from a material which is resistant to an etchant used for patterning the second etching mask (7) before the first-time anisotropic etching is performed. Thus, the edge portion (6) of the first etched region (4) is protected so that its configuration is excellently maintained. By way of example, either of the etching masks is composed of a dielectric material such as a silicon dioxide film, while the other etching mask is composed of a metallic material such as Au and Ti, and the second-time anisotropic etching is performed by using diluted potassium hydroxide.