A method of manufacturing a semiconductor device has forming a first silicon film over the first insulating film, forming a second silicon film over the first silicon film, a first etching the second silicon film in a depth, which the first silicon film is not exposed, in first condition, a second etching a remaining portion of the second silicon film and the first silicon film in a depth, which the first insulating film is not exposed, in second condition which gives a higher vertical etching component ratio than the first condition; and a third etching a remaining portion of the first silicon film in third condition which an etching rate for the first silicon film is larger than an etching rate for the first insulating film as compared to the second condition, wherein an impurity concentration of a first conductivity type of the first silicon film is higher than an impurity concentration of first conductivity type of the second silicon film.