Anisotropic silicon etching in fluorinated plasma

Abstract From the Canadian patent

A method of high rate anisotropic etching of silicon in a high pressure plasma is described. In one embodiment the, etching ambient is a mixture of either NF3 or SF6 an inert, gas such as nitrogen, and a polymerizing gas such as CHF3 that creates conditions necessary for anisotropy not normally possible with nonpolymerizing fluorinated gases in a high pressure regime. The etch process is characterized by high etch rates and good uniformity utilizing photoresist or similar materials as a mask. The present process may advantageously be used to etch deep trenches in silicon using a photoresist mask.