Directed assembly of lamellae-forming block copolymers by using chemically and topographically patterned substrates

The graphoepitaxy technique for the registration and alignment of lamellae-forming block copolymers was investigated. The polymer films were spin-coated from 1.5 wt % toluene solutions and then annealed. The film thickness was measured by ellipsometry on flat regions of the wafers and thicker films within the confining grooves were observed. A cross-sectional SEM inspection of the thicker films showed that the block copolymers materials has uniformly covered both the gold features and the gold confining grooves. The target block copolymers morphology was achieved by chemically patterning confining grooves with bottom surface having neutral wetting properties and groove sidewalls wetted by one of the copolymer blocks. It was observed that the thickness of the deposited polymer film also affects the quality with which the modified graphoepitaxy technique aligns lamellar domains.