OXIDE ETCH SELECTIVITY ENHANCEMENT

摘要

A method of etching exposed silicon oxide on patterned heterogeneous structures is described and includes a gas phase etch using plasma effluents formed in a remote plasma. The remote plasma excites a fluorine-containing precursor in combination with an oxygen-containing precursor. Plasma effluents within the remote plasma are flowed into a substrate processing region where the plasma effluents combine with water vapor or an alcohol. The combination react with the patterned heterogeneous structures to remove an exposed silicon oxide portion faster than an exposed silicon nitride portion. The inclusion of the oxygen-containing precursor may suppress the silicon nitride etch rate and result in unprecedented silicon oxide etch selectivity.

主权项

1. A method of etching a patterned substrate, the method comprising:
placing the patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon oxide portion and an exposed silicon nitride portion; flowing a radical-fluorine precursor into the substrate processing region; flowing a radical-oxygen precursor into the substrate processing region; flowing a hydrogen-and-oxygen-containing precursor into the substrate processing region without first passing the hydrogen-and-oxygen-containing precursor through any plasma, wherein the hydrogen-and-oxygen-containing precursor comprises an OH group; etching the exposed silicon oxide portion, wherein the exposed silicon oxide portion etches at a first etch rate and the second exposed silicon oxide portion etches at a second etch rate which is lower than the first etch rate.