Nanofluidic channels fabricated by e-beam lithography and polymer reflow sealing

The authors developed a facile approach for creating nanofluidic channels by electron beam lithography that used a bilayer e-beam resist consisting of poly(methyl methacrylate) (PMMA) on top of poly(dimethyl glutarimide) (PMGI). In the process, the more sensitive PMGI was fully exposed with channel patterns, and the less sensitive PMMA was only fully exposed with a chain of dot patterns right above the channel patterns. PMMA was then developed to form a chain of holes through which PMGI channels were developed. After closing the holes by thermal reflowing PMMA, channels in PMGI were sealed with PMMA. The current method is capable of fabricating simultaneously channels with different channel widths.