Functional underlayers for dose reduction and collapse mitigation in EUV lithography: a factorial analysis

Abstract

It is renowned that underlayers can enhance photoresist performance in extreme ultraviolet lithography via chemical/physical interactions, but these effects are elusive to identify. Using factorial analysis, we pinpoint which underlayer parameters have or have not an effect on the lithography patterning quality of chemically amplified and metal oxide resists in three proposed experiments. Experimental factors were underlayer thickness, density, surface roughness, surface energy and composition; the outputs were: dose, exposure latitude, line roughness and its correlation length.