A method of making a semiconductor device includes forming at least one device layer over a substrate, forming at least two spaced apart features over the at least one device layer, forming sidewall spacers on the at least two features, selectively removing the spaced apart features, filling a space between a first sidewall spacer and a second sidewall spacer with a filler feature, selectively removing the sidewall spacers to leave a plurality of the filler features spaced apart from each other, and etching the at least one device layer using the filler feature as a mask.