PURPOSE: To detect the end point of etching by depositing a first resist including an impurity element on silicon oxide film and then a normal second resist and etching the second resist until the first resist is exposed by dry-etching the silicon oxide film by a formed resist pattern.

CONSTITUTION: A first resist 3 including an impurity element such as silicon is deposited on silicon oxide film 2 and then a second resist 4 is deposited on it. After that. patterning is performed collectively to the first and second resists 3 and 4, dry etching is performed also to the second resist 4 while performing dry etching to the silicon oxide film 2 by the formed resist pattern, thus detecting the exposure of the first resist 3 according to the change in the amount of emission of an emission spectrum 6 inside plasma 5 and hence detecting the end point of etching easily and positively.