Polymer Engineering Faculty Research


Fabrication Of High Density Silicon Nano-dots by Excimer Laser Irradiation on Block Copolymer Masks

Document Type

Conference Proceeding

Publication Date

Fall 9-2007


We report easy and fast fabrication methods to prepare densely packed polystyrene (PS) and silicon nano-dots using one-step excimer laser irradiation on cylindrically nanopatterned block copolymer materials, without any additional selective etching steps before a non-selective etching. Preferential etching in more ultraviolet (UV)-sensitive block component, and non-selective removal of all block components allowed transferring nanopatterns in block copolymer masks to inorganic silicon substrates, when an appropriate laser intensity was used. Surface melt flows of block components, which severely undermine the initial orders of nanopatterns in a block copolymer mask, were observed at the laser intensity near the ablation threshold of the less UV-sensitive component. Thus, in order to obtain mask-image-like topographic nanopatterns on the target material surfaces, the intensity of excimer laser radiation should be sufficiently lower than the ablation threshold of the less UV-sensitive component as long as the intensity is higher than that of the more UV-sensitive component. Numerical analyses on the photothermal excimer laser ablation in binary mixture systems predicted the presence of a matrix-assisted excimer laser ablation in the less UV-sensitive component at the laser intensity lower than its ablation threshold, owing to the heat conduction from the more UV-sensitive component during the nanoscopic level of time duration.

Publication Title

ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference

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