Anhydride copolymer top coats for orientation control of thin film block copolymers

Abstract

The use of self-assembled block copolymer structures to produce advanced lithographic patterns relies on control of the orientation of these structures in thin films. In particular, orientation of cylinders and lamellae perpendicular to the plane of the block copolymer film is required for most applications. The preferred method to achieve orientation is by heating. The present invention involves the use of polarity-switching top coats to control block copolymer thin film orientation by heating. The top coats can be spin coated onto block copolymer thin films from polar casting solvents and they change composition upon thermal annealing to become “neutral”. Top coats allow for the facile orientation control of block copolymers which would otherwise not be possible by heating alone.