Fluorocarbon film-assisted fabrication of a CoNi mold with high aspect ratio for nanoimprint lithography

Abstract

The availability of durable molds with nanometer-scale features is a bottleneck for nanoimprint lithography and nano-injection molding. Silicon (Si) nanomolds are typically fabricated by electron beam lithography, which is a very expensive technology, and furthermore, the lifetime of the Si mold is also short. This paper presents a very cost effective method for the fabrication of wafer level CoNi nanomolds with an improved residual stress profile without the consumption of a silicon mother mold. For this purpose, a 20nm fluorocarbon antistiction film was applied to the silicon mold prior to seed layer deposition and electroplating to ease the separation of the metal mold without sacrificing a costly mother mold. Step coverage of the fluorocarbon film was found to be dependent on the aspect ratio of nanoscale features. The degree and nature of the stress, as well as the cobalt content in the electroformed mold, were controlled by changing the anode-to-cathode gap. A 6-inch CoNi nanomold was successfully duplicated without consuming the mother mold with this method.