Atmospheric pressure plasma jet pattern transfer using photolithographic masks

The transfer of photolithographically generated structures using ion beams/plasmas is a widely used technology with a wide range of applications. However, these techniques generally require expensive and high-maintenance vacuum systems, which is why a new atmospheric approach of pattern transfer is being pursued using atmospheric pressure plasma jet (APPJ) etching. In the present study, pattern transfer by plasma jet with a photopolymer masking into fused silica as a substrate is investigated. Etching was carried out with varying mask line widths and then subsequently analyzed using white light interferometry (WLI) and atomic force microscopy (AFM). It was shown that structures can be transferred into fused silica using a standard photoresist (AZ 4562). The faster etching of the resist significantly widens the valleys of the structure. Smaller line widths lead to a smaller etching depth, whereby the depth is reduced from 110 nm at 200 µm gap width of the mask to 30 nm at 1 µm for identical etching conditions.