Overcoming material challenges for replication of “motheye lenses” using step and flash imprint lithography for optoelectronic applications

Abstract

In this article, the fabrication and characterization of two-dimensional (2D) and three-dimensional (3D) structures using focused ion beam milling onto templates for step and flash imprint lithography (S-FIL) is discussed. It has been discovered that the 2D linewidth and height are closely related to the ion dose. At low doses (∼1pC∕μm2), the surface of the quartz template swells, thus, affecting the shape of the subsequent imprint. Furthermore, it has been shown that during UV curing of the S-FIL resist, the polymeric resist layer contracts as it solidifies, resulting in a dimensionally reduced replication of the original structure. The authors introduce a method to overcome the problem for 3D patterns, using a “multilayer” imprinting technique and apply this technique to the fabrication of “motheye” lenses. With respect to the imprinted replica, they show that the feature profile using this approach has a high fidelity in comparison to the template structure, and thus motheye lenses can be consistently replicated employing the S-FIL technology.