Fabrication of high-aspect-ratio polymer nanochannels using a novel Si nanoimprint mold and solvent-assisted sealing

Abstract

We present a low cost nanofabrication method to fabricate high-aspect-ratio (HAR) polymer nanochannels using a novel silicon nanoimprint mold fabrication technique and a solvent-assisted sealing method. These nanofluidic channels are being developed for single biomolecule detection. The silicon nanoimprint mold fabrication process is based on the combination of anisotropic etching of silicon by potassium hydroxide (KOH) solution and the local oxidation of silicon (LOCOS) process. The resulting high-aspect-ratio silicon mold has smooth sidewalls owing to the anisotropic KOH etching process along the silicon crystalline geometry as well as the LOCOS process. The nanostructures in the nanoimprint molds that form the nanochannels can be easily controlled by the initial micropattern sizes defined using conventional UV lithography and the oxidation time, making this technique a practical solution for low cost and high-throughput HAR silicon nanoimprint mold fabrication. Nanoimprint molds having aspect ratios of more than 1:5.5 (width: 200 nm, height: 1.1 μm, length: 1 cm) were successfully fabricated. Nanoimprinting technique was used to create poly(methyl methacrylate) (PMMA) nanotrenches out of this nanoimprint mold. A novel solvent-assisted sealing technique was developed in order to seal the HAR PMMA nanotrenches. This technique enables the generation of nanochannels with various nanoscale dimensions without the need for complicated and expensive nanolithography tools.