Patent ID: 8372756

Claim:
A process for selectively etching a material comprising SiO 2 preferentially to silicon, the method comprising the steps of: placing a silicon substrate having a layer of a material comprising SiO 2 within a reactor chamber equipped with an energy source; creating a vacuum within the chamber; introducing into the reactor chamber a reactive gas mixture comprising a fluorine compound, a polymerizable fluorocarbon, and an inert gas, wherein no oxygen is added to the reactive gas mixture, wherein the fluorine compound is selected from the group consisting of: NF 3 , F 2 , F 2 created in situ, and a mixture of F 2 in an inert gas, and wherein the polymerizable fluorocarbon comprises a compound having the formula C h F i wherein h is a number ranging from 4 to 6 and i is a number ranging from h to 2h+2; activating the energy source to form a plasma activated reactive etching gas mixture within the chamber; and selectively etching the material comprising SiO 2 preferentially to the silicon substrate.