Patent ID: 7655568

Claim:
A method for manufacturing a semiconductor device, the method comprising: (a) sequentially forming an underlying layer, a hard mask layer, an anti-reflection film, and an Si-containing first photoresist film over a semiconductor substrate; (b) forming a first photoresist pattern by exposing and developing the first photoresist film using a first exposure mask; (c) performing O 2 plasma treatment over the first photoresist pattern; (d) forming a second photoresist film over the O 2 plasma-treated first photoresist pattern, and forming a second photoresist pattern by exposing and developing an alternate region, relative to the first photoresist pattern, using a second exposure mask; (e) etching the anti-reflection film with the first and second photoresist patterns as a mask, thereby forming an anti-reflection pattern; and (f) forming a hard mask pattern by etching the hard mask layer with the anti-reflection pattern as a mask, and etching the underlying layer with the hard mask pattern as a mask, thereby forming an underlying pattern.