Fabrication of sub-40 nm nanofluidic channels using thin glass-glass bonding

This paper presents a method for characterizing the thin glass-glass bonding process for the fabrication of nanofluidic channels with depths down to the nanometer scale without cost-expensive lithography. Nanofluidic channels were fabricated on a substrate of borosilicate glass (coverslip, thickness of 160 μm) using the buffered oxide wet etching process, and preheated in a furnace at 400 °C with another flat coverslip before glass-glass fusion bonding (580 °C). We demonstrate that glass-glass nanofluidic channels as shallow as 40 nm with a low aspect ratio of 0.0002 (depth to width) can be obtained. The main advantages of the technique are the good transparency and thickness of nanofluidic chip, which allows optical fluorescence microscopy to be used at high magnification for applications such as protein and biomolecule detection.