Patent ID: 8313998

Claim:
A method for manufacturing a semiconductor device, comprising: forming a stacked body by alternately stacking a plurality of insulating layers and a plurality of conductive layers above a substrate; forming a resist film above the stacked body; plasma-etching the insulating layers and the conductive layers by using the resist film as a mask; forming a hardened layer in an upper surface of the resist film by plasma treatment using a gas containing at least one selected from a group consisting of boron, phosphorus, arsenic, antimony, silicon, germanium, aluminum, gallium, and indium, the hardened layer containing at least one selected from the group consisting of the boron, the phosphorus, the arsenic, the antimony, the silicon, the germanium, the aluminum, the gallium, and the indium; and slimming a plane size of the resist film by plasma treatment using an oxygen-containing gas in a state where the hardened layer is formed in the upper surface of the resist film.