Single- and Multi-Directional Slanted Plasma Etching of Silicon under Practical Plasma Processing Conditions

A novel plasma etching technique was developed to obtain single- and multi-directional slanted etch profiles of silicon using a Faraday cage system. Etching was performed by a cyclic process consisting of alternating etching and deposition steps using SF6 and C4F8 plasmas, respectively, under practical plasma processing conditions. The single-directional slanted plasma etching was achieved using a Faraday cage with a single horizontal grid plane. Mask erosion characteristics played an important role in the prediction and control of the etch profiles during the single-directional slanted plasma etching. Multi-directional, such as double and quadruple, slanted plasma etchings were also performed with Faraday cages with two and four slanted-grid planes, respectively. This work offers a novel method for performing single- and multi-directional slanted plasma etchings of silicon under practical plasma processing conditions.