Patent ID: 8999856
Filing Date: 2015-04-07
Classification: C09K,H01J,H01L

Abstract:
1. A method of selectively etching silicon nitride from a substrate comprising a silicon nitride layer and a silicon oxide layer, the method comprising: flowing a fluorine-containing gas into a plasma generation region of a substrate processing chamber; applying energy to the fluorine-containing gas to generate a plasma in the plasma generation region, the plasma comprising fluorine radicals and fluorine ions; filtering the plasma to provide a reactive gas having a higher concentration of fluorine radicals than fluorine ions, wherein the fluorine ions are eliminated traveling through an ion suppression plate from the plasma generation region to the substrate; flowing the reactive gas into a gas reaction region of the substrate processing chamber, wherein flowing the reactive gas comprises passing the fluorine radicals through a showerhead into a gas reaction region, wherein the showerhead is disposed between the plasma generation region and the gas reaction region, and wherein the showerhead is electrically insulated from the ion suppression element; and exposing the substrate to the reactive gas in the gas reaction region of the substrate processing chamber, wherein the reactive gas etches the silicon nitride layer at a higher etch rate than the reactive gas etches the silicon oxide layer.