Shape change of cured 2D and 3D nanostructures from imprint lithography

Abstract

Nanosculpting, the fabrication of two-and three-dimensional shapes at the nanoscale, enables applications in photonics, metamaterials, multi-bit magnetic memory, and bio-nanoparticles. A promising high resolution and high throughput method for nanosculpting is nanoimprint lithography (NIL). A key requirement to achieving manufacturing viability of nanosculptures in NIL is maintaining image fidelity through each step of the imprinting process. In particular, polymer densification during UV curing can distort the imprinted image. Here we study the shape changes introduced by polymer densification and develop a forward method for predicting changes in nanoscale geometries from UV curing. We show that shape changes by polymer densification are governed by the Poisson's ratio, the shrinkage coefficient of the polymer resist, and the geometric aspect ratios of the nanosculpted shape. We also show that the size of the residual layer does not impact the final profile of the imprinted shape.