Symmetry Plays a Key Role in the Erasing of Patterned Surface Features

TL;DR

This study demonstrates that the initial symmetry of surface patterns on thin films governs their relaxation dynamics, with experimental results confirming theoretical predictions and revealing power-law decay behavior relevant for nanolithography.

Contribution

It shows that initial symmetry controls surface relaxation patterns and validates lubrication theory with experimental data for capillary-driven surface evolution.

Findings

Surface profile shape at late times depends on initial symmetry.

Perturbation amplitude relaxes as a power-law in time.

Experimental results agree with lubrication theory predictions.

Abstract

We report on how the relaxation of patterns prepared on a thin film can be controlled by manipu- lating the symmetry of the initial shape. The validity of a lubrication theory for the capillary-driven relaxation of surface profiles is verified by atomic force microscopy measurements, performed on films that were patterned using focused laser spike annealing. In particular, we observe that the shape of the surface profile at late times is entirely determined by the initial symmetry of the perturba- tion, in agreement with the theory. Moreover, in this regime the perturbation amplitude relaxes as a power-law in time, with an exponent that is also related to the initial symmetry. The results have relevance in the dynamical control of topographic perturbations for nanolithography and high density memory storage.