High-resolution fused silica mold fabrication for UV-nanoimprint

This paper describes the fabrication steps developed to pattern nano scale features on thin silica wafers. The optimization of e-beam exposure dose is presented. The use of a chrome layer on top of the silica wafer implies higher doses to crosslink the negative NEB22 resist, but the results show a very large window process. Specific etching processes have been developed. It is demonstrated how the micro-trenching and CD bias are reduced. Thanks to the optimization of both the exposure dose during e-beam lithography and the plasma dry etch steps, features with a resolution as low as 30 nm have been achieved.