Dewetting of the residual layer of annealed nanoimprinted polystyrene films

Abstract

International audienceThe presence of a residual layer at the end of a classical NanoImprint Lithography (NIL) process is at the root of many issues when NIL is used to manufacture resist patterns used later as an etching mask. In this paper, we investigate how the spontaneous break-up of annealed polystyrene films, a phenomenon called dewetting, can produce residual-layer-free polymer patterns. Although the dewetting of flat polymer films has been characterized for decades, little interest has been focused on patterned films. We present exploratory experiments conducted on polystyrene 30 kg/mol ultra-thin films. The samples are embossed using thermal NIL with a specific spatially modulated space/line patterned mold, and then annealed at 50 degrees C above the glass transition temperature. The resulting patterns are then interpreted as a competition between surface tension and van der Waals forces. Finally, a quantitative analysis is made in the framework of lubrication theory, with the help of a finite volume simulation tool

Viscoelastic effects and anomalous transient levelling exponents in thin films

“…New ways to probe the dynamics of viscoelastic materials have been explored [37]. Thin viscoelastic films have been studied experimentally by dewetting [38,39], and relaxation of nanoimprinted patterns [40,41], in particular. From the theoretical point of view, viscoelastic thin-film equations have been derived, using the linear Jeffreys model [3,[42][43][44][45].…”