Fabrication Method for Surface Gratings Using a Faraday Cage in a Conventional Plasma Etching Apparatus

Directional etching in a conventional plasma etcher is achieved by placing the substrate in a Faraday cage fixed on the cathode, whose top plane is gridded and slanted with respect to the substrate surface. The etching direction is determined by an angle that the gridded plane makes with the substrate normal. Surface gratings with either symmetric or asymmetric V‐grooves are obtained using the cage covered with two slanted grid planes. Furthermore, the slopes of the gridded planes determine the cross‐sectional shape of the V‐groove.