Density variation of nanoscale patterns in thermal nanoimprint lithography

Density variation of nanoscale patterns in thermal nanoimprint lithography was studied both by experiments and molecular dynamics simulations. A simple soft imprinting technique was used to fabricate various nanopatterns (70 nm and 600 nm lines and 150 nm dots) over a large area (2x3 cm(2)). Local density was measured by the relative magnitude of van der Waals interactions between a sharp tip and the patterned surface. In order to investigate the mechanism of density variation, molecular dynamic simulations were performed. Experimental and simulation results demonstrated that the density of the pressed region (valleys) was higher than that of the cavity region (hills) when a simple amorphous polymer is thermally imprinted with a patterned mold.(c) 2007 American Institute of Physics.