Patent ID: 8053370

Claim:
A method for forming a semiconductor device, comprising: providing a substrate having a structural layer thereon; forming a hard mask layer on the structural layer; forming a photoresist layer on the hard mask layer; patterning the photoresist layer to form multiple main photoresist patterns respectively separated from each other by a first width and multiple dummy photoresist patterns respectively separated from each other by a second width which is smaller than the first width, wherein a very dummy photoresist pattern is separated from the closest main photoresist pattern by one second width; patterning the hard mask layer using the patterned photoresist layer as a mask to partially expose the hard mask layer to allow the exposed hard mask layer to have a shape corresponding to the main photoresist layer; and patterning the structural layer using the patterned hard mask layer as a mask to partially expose the structural layer to allow the exposed structural layer to have a shape corresponding to the main photoresist layer; wherein the second width is 50%-70% of that of the first width; wherein the hard mask layer comprises a first hard mask layer formed on the structural layer and a second hard mask layer formed on the first hard mask layer; wherein the second hard mask layer is etched to form multiple first openings respectively separated from each other by the first width, whereas the second hard mask layer is free of second openings respectively separated from each other by the second width.