Using a same mask for direct print and self-aligned double patterning of nanosheets

Abstract

A method of forming a semiconductor structure includes forming a nanosheet stack including alternating layers of a sacrificial material and a channel material over a substrate, the layers of channel material providing nanosheet channels for one or more nanosheet field-effect transistors. The method also includes forming a hard mask stack over the nanosheet stack, and forming a patterning layer over the hard mask stack. The method further includes patterning a lithographic mask over the patterning layer, the lithographic mask defining (i) one or more first regions for direct printing of one or more fins of a first width in the nanosheet stack and the substrate and (ii) one or more second regions for setting the spacing between two or more fins of a second width in the nanosheet stack and the substrate using self-aligned double patterning. The second width is less than the first width.