Patent ID: 7678537

Claim:
A method of forming an image in a photoresist layer, comprising: (a) forming said photoresist layer over a substrate; (b) forming a topcoat layer on a top surface of said photoresist layer, said topcoat layer comprising a first polymer and a second polymer, said second polymer different from said first polymer, said second polymer miscible with said first polymer, said first and second polymers of said topcoat layer dispersing non-homogenously in a vertical direction perpendicular to said top surface of said photoresist layer; (c) forming a layer of immersion fluid between said topcoat layer and a final lens element or window of an immersion lithography system; (d) exposing said photoresist to radiation through a photomask having opaque and clear regions, said opaque regions blocking said radiation and said clear regions being transparent to said radiation, said radiation changing the chemical composition of regions of said photoresist layer exposed to said radiation, forming exposed and unexposed regions in said photoresist layer; and (e) removing either said exposed regions of said photoresist layer or said unexposed regions of said photoresist layer.