Using Anodic Aluminum Oxide Film and Nanoimprint to Produce Polymer Anti-counterfeit Labels

Abstract

An anodic aluminum oxide (AAO) film fabrication process and photolithography were combined to produce a patterned array of nano-hemispheres. This barrier was then used as the substrate on which conductive metals were vapor-deposited to produce electrodes. Nano electroforming was then utilized to deposit nickel on the surface of the array of nano-hemispheres. The oxidized aluminum was etched with phosphoric acid to form a complementary array of nano-pits. Finally, the technique of nanoimprinting was used to transfer the unique structure of the barrier to a polymer. Scanning electron microscopy (SEM) was used to explore the effects of different voltages on the fabrication process and of phosphoric acid etching time on the shape of the barrier. An atomic force microscope (AFM) was used to verify that the nano-array structure of the aluminum oxide film had been completely replicated on the polymer. The regular arrangement of nano-hemispheres refract light and also cause interference, such an array is referred to as a photonic crystal. This type of special structure can be used in counterfeit protection and in many other optical applications.