Nano-depth grooves formed through O2 plasma etching in the presence of PTFE

Abstract

In this paper, we describe a simple method for fabricating nano-depth grooves in glass. In our method, the depth of the grooves can be easily controlled at the several tens of nanometers scale for the vertical features by simply applying O2 plasma in the presence of polytetrafluoroethylene (PTFE). Using atomic force microscopy, we found that (1) the etching rate varies in different types of glasses; (2) the etched glass surface is flat (root-mean-square roughness ≈1 nm); (3) the etched depth of the glass almost linearly depends on the output power of the plasma equipment; and (4) the etching is influenced by the surface area of PTFE that is exposed to O2 plasma in the etching chamber. Furthermore, using these nano-depth groove structures, we made nano-depth (≈60 nm) fluidic channels as a demonstration of micro/nanofabrication. The channels are composed of a silicon substrate and etched glass anodically bonded together. This simple method is a useful technique for the production of nano-depth fluidic channels.