Patent ID: 8642481
Filing Date: 2014-02-04
Classification: H01L

Abstract:
1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon-and-nitrogen-containing region, the method comprising: flowing each of a fluorine-containing precursor and an oxygen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the plasma region to produce plasma effluents, wherein an atomic flow ratio of oxygen to fluorine provided by the fluorine-containing and oxygen-containing precursors is greater than about 20:3; and etching the exposed silicon-and-nitrogen-containing region by flowing the plasma effluents into the substrate processing region through an ion suppressor configured to provide a higher concentration of radicals than ions, and wherein the oxygen oxidizes exposed silicon rendering silicon domains essentially unetchable by the fluorine-containing plasma effluents.