Patent ID: 7807336

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