A method of manufacturing a semiconductor device comprises preparing a working film to be processed, forming an adhesion improving region on the working film for increasing an adhesion between the working film and a mask material containing carbon, forming the mask material on the working film, forming a resist pattern on the mask material, the mask material having a higher etching resistance for the working film than the resist pattern, transferring the pattern of the resist pattern onto the mask material, and etching the working film by using the mask material as a mask.