On the Modeling of Step-and-Flash Imprint Lithography using Molecular Statics Models

We introduce linear and nonlinear molecular statics models for the prediction of the material response of polymerized networks in cured etch-barrier layers that are formed during the so-called Step-and-Flash Imprint Lithography (SFIL) process. The molecular structure of the polymerized network is obtained via a Monte-Carlo simulation of the chemical reactions that take place during the curing of the etchbarrier layer. The resulting molecular structure consists of a lattice of point mass particles with pairwise, nearest-neighbor, force interactions governed by potentials. We introduce three molecular statics models: (1) A linear model assuming small deformations and inter-molecular bonds governed by quadratic force potential functions. (2) A non-linear model allowing for large deformations, still with quadratic force potential functions. (3) A non-linear model allowing for large deformations and assuming non-linear Lennard-Jones potential functions. We demonstrate the application of these molecular models by showing numerical results on the deformation of a small-size (50×50×50 nm) representative feature in common etch-barrier layers. These molecular statics models simulations are compared to the results obtained by finite element approximations of a linear elasticity model in which the shrinkage of the feature is enforced by the thermal expansion coefficient (CTE).