Patent ID: 8828868

Claim:
A method for forming a hard mask in semiconductor device fabrication, comprising: forming first and second patterned material layers on a third material layer, the second patterned material layer only covering the top of predetermined regions of the first patterned material layer; changing a property of the exposed top and side portions of the first patterned material layer using the second patterned material layer as a mask, so as to form property-changed roofs at the exposed top portions of the first patterned material layer and form property-changed sidewalls with a predetermined width at the exposed side portions of the first patterned material layer; removing the second patterned material layer; and removing portions of the first patterned material layer which have exposed tops and an unchanged property and are located between the property-changed sidewalls, so as to form the hard mask, wherein patterns in the first and second patterned material layers are linear patterns, and at least some patterns in the predetermined regions of the first patterned material layer have linewidths larger than twice the predetermined width.