Development of deformation-based nanoimprint technique for advanced functional applications

Abstract

Holograms are one of the anti-counterfeiting solutions which have been used in the manufacturing and finance sector to secure the authenticity of their products in recent years. Everyday examples are on banknotes, credit cards, or on package of pharmaceutical products. Holograms are formed on materials surface through a matrix of micro-features. Not only offering optical enhancement such as holograms, microfeatures on material surface can also be used for various advanced functional application in biology, electronics, etc. Hence, a method to replicate these microfeatures on different materials surface are necessary. Various different solutions have been explored in past studies for both non-crystalline and crystalline materials.

In this project, we developed a deformation-based technique to successfully emboss COC and PMMA substrates with sub-2μm features. This technique includes: (i) a comprehensive fabrication route for micro to nano-size metal shim, (ii) a replication system that completely compensate for parallelism issue of the instruments, and (iii) a brief study on how holding time during embossing affect the feature height replicated on polymeric substrates. This success allowed more non-crystalline materials testing using this new technique.

Furthermore, we also explored a similar system for metallic materials. The experimental system was able to fully emboss a small Aluminium 2024 substrate of 10mm diameter. However, the experimental die fabrication process for a low-cost superhard Diamond-like-carbon (DLC) die failed to deliver. New fabrication process for this proposed DLC die is needed so that total micro-feature replication can be achieved.