Patent ID: 7235347

Claim:
A method for carrying out positive tone lithography with a carbon dioxide development system, comprising the steps of: (a) providing a substrate, the substrate having a polymer resist layer formed thereon, (b) exposing at least one portion of the polymer resist layer to radiant energy causing a chemical shift to take place in the exposed portion and thereby form at least one light field region in the polymer resist layer while concurrently maintaining at least one portion of the polymer layer unexposed to the radiant energy to thereby form at least one dark field region in said polymer resist layer; (c) optionally baking the polymer resist layer; (d) contacting the polymer resist layer to a carbon dioxide solvent system, said solvent system comprising a polar group, under conditions in which said at least one light field region is preferentially removed from said substrate by said carbon dioxide solvent system as compared to said at least one dark field region; wherein said carbon dioxide solvent system comprises a first phase and a second phase, said first phase comprising carbon dioxide and said second phase comprising a polar fluid, with said at least one light field region being preferentially soluble in said polar fluid as compared to said at least one dark field region; and wherein said solvent system further comprises a polyol.