Interface-controlled complex one-dimensional nanopatterning in a combined photo- and soft-lithography

Abstract

The fabrication of micro/nano-structure is one of the most popular and intensive research topics recently. Among many kinds of methodologies, soft lithography has powerful merits due to their inexpensive, fast and easy process for large area nano patterning. In this study, we especially concentrate on patterning of one-dimensional nanostructure through modified soft lithography. Firstly, we focus on the dewetting phenomena of polystyrene occurred in the interface between PDMS mold. When we heat PS thin film above glass transition temperature, PS fluid forms line pattern following the concave of PDMS mold. We increase the line pattern density through the phenomena, with control of annealing time, PS film thickness and molecular weight of PS. Dewetting induced line pattern appears when sufficient annealing time is given. Film thickness of PS does not affect on the line width or annealing time much. Molecular weight of PS have an critical effect on annealing time, large molecular weight of PS requires longer annealing time to get regular dewetting line pattern. Second, we fabricate multisegment line pattern through soft lithography combined with photolithography. From the photolithography process, we made bimetallic substrate. In this step we also apply various metals for line pattern. Then we control the dimension of line width with variation of the line width of PDMS mold and PS film thickness. Through these studies, we explore detail aspect of soft lithography in the way of interface control, also extend the use of soft lithography grafting on photolithography. We hope that these results help us to extend the consideration of soft lithography, also enlarge the field of application for actual use such as electronic and optical devices.