Patent ID: 8394577

Claim:
A process for forming a pattern, consisting essentially of the steps of coating a chemically amplified resist composition on a processable substrate, prebaking the coating to remove any excess solvent therein to form a resist film, exposing patternwise the resist film to high-energy radiation, optionally post-exposure baking, developing the exposed resist film with a developer, and heat treating to form a resist pattern that has a reduced LER compared with a resist pattern that is not subjected to post-development heat treatment, wherein the post-development heat treating step is at a temperature which is equal to or higher than the temperatures of the prebaking and post-exposure baking steps and a change of pattern line width by the heat treatment is less than 10%, said chemically amplified resist composition comprising a base resin, an acid generator, and a solvent, wherein the resist film of the composition changes its solubility in the developer under the action of an acid generated by the acid generator upon exposure to high-energy radiation, the solvent is present in a total amount of 1,400 to 5,000 parts by weight per 100 parts by weight of the base resin, the solvent comprises propylene glycol monomethyl ether acetate (PGMEA) and ethyl lactate which are present in a total amount of at least 60% by weight of the total solvent weight, the solvent further comprises at least one solvent selected from the group consisting of γ-butyrolactone, alkyl acetoacetate, dipropylene glycol methyl ether acetate, dipropylene glycol butyl ether, tripropylene glycol butyl ether, ethylene carbonate, and propylene carbonate, in a proportion of 0.2% to 20% by weight of the total solvent weight.