Patent ID: 8652869

Claim:
A method for roughening a substrate surface comprising: a first step of forming a protection film on a surface of a semiconductor substrate; a second step of forming an opening in the protection film; a third step of isotropically etching a surface of the semiconductor substrate on which the protection film is formed by using the protection film in which the opening is formed as a mask so as to form an etched first concave under the opening and its vicinity area; a fourth step of etching a surface of the semiconductor substrate on which the protection film is formed by using the protection film in which the opening is formed as a mask so as to remove an oxide film formed on the etched surface of the first concave formed under the opening and its vicinity area; a fifth step of anisotropically etching a surface of the semiconductor substrate on which the protection film is formed by using the protection film in which the opening is formed as a mask so as to form a second concave under the opening and its vicinity area; and a sixth step of removing the protection film.