Methods for etch of sin films

摘要

A method of selectively etching silicon nitride from a substrate comprising a silicon nitride layer and a silicon oxide layer includes flowing a fluorine-containing gas into a plasma generation region of a substrate processing chamber and applying energy to the fluorine-containing gas to generate a plasma in the plasma generation region. The plasma comprises fluorine radicals and fluorine ions. The method also includes filtering the plasma to provide a reactive gas having a higher concentration of fluorine radicals than fluorine ions and flowing the reactive gas into a gas reaction region of the substrate processing chamber. The method also includes exposing the substrate to the reactive gas in the gas reaction region of the substrate processing chamber. The reactive gas etches the silicon nitride layer at a higher etch rate than the reactive gas etches the silicon oxide layer.

主权项

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.