Abstract
We demonstrated a multilayered, residual-free nanostructure by stacking a one-dimensional grating in an orthogonal arrangement via reverse thermal nanoimprinting and reactive ion etching technique using a single material (PMMA). We found that a good pattern transfer with minimal residual layers was mainly determined by four important factors: the concentration of PMMA in toluene solution, the type of fluorosilane used on the mold surface, and the temperature and pressure used in reverse nanoimprinting. The first layer was reverse-nanoimprinted at the temperature of 150 degrees C, while the subsequent layers were achieved at the onset temperature of the glass transition of PMMA. Experimental results showed that the compression of the bottom layer was inevitable due to a change in mechanical property of the PMMA after repeated reverse nanoimprinting process. (C) 2011 Elsevier B.V. All rights reserved.