Patent ID: 8603919

Claim:
A method for fabricating a semiconductor device, comprising: forming an etch target layer over a substrate; forming a first hard mask layer over the etch target layer; forming a second hard mask pattern having lines that extend in a first direction over the first hard mask layer; forming a third hard mask layer over the second hard mask pattern; forming a sacrificial pattern having lines that extend in a second direction crossing the first direction in an oblique direction over the third hard mask layer; forming a cell spacer on sidewalls of the sacrificial pattern; removing the sacrificial pattern; etching the third hard mask layer using the cell spacer as an etch barrier to form a third hard mask pattern; etching the first hard mask layer using the third hard mask pattern and the second hard mask pattern as etch barriers to form a first hard mask pattern; forming an elliptical opening having an axis extending in the second direction by etching the etch target layer using the first hard mask pattern as an etch barrier; and forming a silicon layer that fills the elliptical opening.