Polymer shrinkage of hot embossed microstructures for higher aspect ratio and smaller size

In this paper, a facile polymer fabrication approach by combination of hot embossing and polymer shrinking is presented to reduce the feature size and dramatically increase the aspect ratio of imprinted microstructures. Pre-pattern is hot embossed on a heat shrinkable polymer at low temperature to reserve a good shrinkage and recovery. The projected structures are removed by a polishing process. Finally, new microstructures derive from the pre-pattern at the absence of removed materials after baking process. Through this way, both two- and three-dimensional hot embossed structures were successfully shrunk into a smaller scale. The width along two lateral directions reduced to two-fifths, and the height along vertical direction increased by 6 times. Detailed features at different layers exhibit clearly three-dimensional shrunk microstructures. This polymer-shrinking process brings a new way to extend the fabrication capability of hot embossing process.