Fabrication of Polymer Micropyramid/Nanolens Combined Structures Using Microstructured Nanodimpled Aluminum Stamp

Abstract

In this study, we present an efficient and low-cost fabrication technique of polymer micropyramid/nanolens combined structures (MPNL-CS). The present fabrication technique is based on hot embossing of polymer substrates using a microstructured nanodimpled aluminum (MNA) stamp. The MNA stamp for the replication of polymer MPNL-CS was realized by combining three fabrication steps. (1) A nickel stamp with micropyramid array was manufactured by electroforming onto an anisotropically wet-etched silicon substrate. (2) A reverse micropyramid cavity array was transcribed on an electropolished aluminum substrate by microindentation with the nickel stamp. (3) The MNA stamp was finally realized by forming nanodimple arrays onto the reverse micropyramid array on the aluminum substrate through an electrochemical oxidation (anodization) process. In the final step, we have optimized the electrochemical oxidation process to realize nanodimple arrays at the sharp edge reverse micropyramid without defects. The MPNL-CS were successfully replicated on polymer substrates via a hot embossing process with the fabricated MNA stamp through investigating the effect of embossing pressure on the transcription quality of MPNL-CS. The present fabrication technique can be widely applied to the realization of various types of three-dimensional micro/nano combined structures. (C) 2011 The Japan Society of Applied Physics