Multi-step bake apparatus and method for directed self-assembly lithography control

Abstract

A method of forming a patterned substrate includes casting a layer of a block copolymer having an intrinsic glass transition temperature Tg, on a substrate to form a layered substrate. The method also includes heating the layered substrate at an annealing temperature, which is greater than about 50° C. above the intrinsic glass transition temperature Tg of the block copolymer, in a first atmosphere. The method further includes thermally quenching the layered substrate to a quenching temperature lower than the intrinsic glass transition temperature Tg, at a rate of greater than about 50° C./minute in a second atmosphere. The method further includes controlling an oxygen content in the first and second atmospheres to a level equal to or less than about 8 ppm to maintain the annealing and quenching temperatures below a thermal degradation temperature Td of the block copolymer.

Dependencies are inferred from the claim text.