Patent ID: 9263283
Filing Date: 2016-02-16
CPC Classification: H01J,H01L

Claim Text:
1. An etching method comprising: loading a substrate into a processing chamber, the substrate including a silicon nitride film, polycrystalline silicon patterns formed on the silicon nitride film and a silicon oxide film formed on a surface of the silicon nitride film and top surfaces and side surfaces of the polycrystalline silicon patterns; introducing a processing gas containing (i) a plasma excitation gas, (ii) a carbon and fluorine containing gas consisting of a CHF etching the silicon oxide film formed on the top surfaces of the polycrystalline silicon patterns and the surface of the silicon nitride film in the processing chamber by using a plasma of the processing gas in the processing chamber while depositing a protective film containing carbon and fluorine obtained by dissociation of the carbon and fluorine containing gas on the surface of the silicon nitride film exposed during etching the silicon oxide film, wherein the silicon nitride film is etched by said etching 4 nm or less in depth, wherein the plasma is generated by microwaves supplied by using a radial line slot antenna.