Nano-scale reactive-ion dry-etching with electron-beam-baked resist

We developed a nano-scale electron-beam (EB) lithography procedure using a high-resistance electron-beam resist for fabrication of nano-biodevices. After a conventional EB image-development procedure, we newly added a resist-baking procedure using an EB exposure with a density of over 50 mC/cm₂, and then performed a reactive-ion dry-etching. We found that the EB-baked resists were highly resistant against dry-etchings, resulting in preserving a clear-pattern of the EB-lithographed image up to a sub 50 nm scales. By using this EB baking method, we successfully fabricated nano-fluidics structures, and observed the smooth-translocation of single λ DNA molecules. This nano-scale dry-etching using EB-baked resist would be a general procedure for EB lithography fabrications of DNA nano-fluidics and sensing structures.