Patent ID: 9633867
Date: 2017-04-25
CPC Classifications: H01J,H01L

Claim:
1. A method of anisotropically etching a tungsten-containing material on a semiconductor substrate in a plasma etching apparatus, the method comprising: (a) providing a semiconductor substrate comprising a tungsten-containing material to a plasma etching process chamber; (b) introducing a first process gas comprising Cl (c) removing the first process gas from the plasma etching process chamber after (b); (d) introducing a second process gas comprising an oxygen radical source to the plasma etching process chamber and forming a plasma comprising oxygen radicals to react the plasma with the new exposed surface of the tungsten-containing material and thereby form a passivation layer, wherein the passivation layer consists essentially of one or more compounds that include tungsten and oxygen; and (e) removing the second process gas from the plasma etching process chamber after (d), wherein the method predominantly etches the tungsten-containing material in a selected direction.