Impact of trench width roughness on the graphoepitaxial assembly of block copolymers

In this paper, the authors investigated constraints on the quality of topographic features needed for graphoepitaxial assembly of cylinder forming poly(styrene-b-methyl methacrylate) (PS-b-PMMA) thin films, showing the impact of trench width roughness (TWR) on feature size uniformity and defect formation. Topographically patterned substrates were prepared using chemically amplified photoresist and reactive ion etching in conjunction with commercially available lithographic tools and masks. A dose/focus array was utilized to systematically produce trenches with widths between 40 and 400nm with roughness of 5–35nm on top of which block copolymers were assembled. Scanning electron microscopy images were taken and analyzed using IMAGEJ software for the metrology of the trenches and ordered block copolymer domains after the removal of the PMMA cylinders. Analysis showed little or no change in domain size variation of the block copolymer with respect to the TWR of lithographically defined features. The impact o...