Patent ID: 7214576

Claim:
A manufacturing method of a semiconductor device, comprising: forming a first protrusion; forming a second protrusion which is higher than the first protrusion; forming a first sidewall on a side surface of the second protrusion; forming a first film so that a surface of the first film is located lower than the second protrusion; forming a mask on a side surface of the first sidewall on a side surface of the second protrusion which protrudes from the surface of the first film; and etching the first film with the mask so as to form a second sidewall on the side surface of the first sidewall on the side surface of the second protrusion but not to form the second sidewall on a side surface of the first protrusion, the second sidewall being formed of the mask and the first film, wherein the forming the mask comprises: forming a second film on the first film and the second protrusion which protrudes from the surface of the first film; and etching back the second film so as to leave the second film on the side surface of the first sidewall on the side surface of the second protrusion, and the left second film as the mask.