Abstract A method of manufacturing a semiconductor device, in which a layer of silicon nitride (3) overlying a silicon oxide layer (4) present on a substrate (2) is etched by bringing it into contact with substantially only uncharged constituents of a plasma formed in a reactor to which a substantially oxygen-free gas or gas mixture is supplied. According to the invention, 0.1 to 25% by volume of a halogen different from fluorine or of a compound containing a halogen different from fluorine are added to this gas or gas mixture which contains fluorine or a fluorine compound. Thus, a high etching selectivity of silicon nitride with respect to silicon oxide is obtained, which moreover, does not vary during etching.
A method of manufacturing a semiconductor device, in which a layer of silicon nitride present on a substrate is etched by bringing the layer into contact with substantially only uncharged constituents of a plasma formed in a reactor to which a substantially oxygen-free gas or gas mixture is supplied which comprises fluorine or a fluorine compound, characterised in that 0.1 to 25% by volume of a halogen different from fluorine or of a gaseous compound containing a halogen different from fluorine are added to the gas or gas mixture supplied to the reactor.
Claim 2
Independent Claim
93 words
A method of manufacturing a semiconductor device, in which a layer of silicon nitride present on a substrate is etched by bringing the layer into contact with substantially only uncharged constituents of a plasma formed in a reactor to which a substantially oxygen-free gas or gas mixture is supplied which comprises fluorine or a fluorine compound, characterised in that 0.1 to 25% by volume of a halogen different from fluorine or of a gaseous compound containing a halogen different from fluorine are added to the gas or gas mixture supplied to the reactor.
Claim 3
Dependent Claim
27 words
A method as claimed in Claim 1, characterised in that bromine or a bromine compound is added to the gas or gas mixture supplied to the reactor.
Claim 4
Dependent Claim
17 words
A method as claimed in Claim 2, characterised in that the bromine compound is CF 3 Br.
Claim 5
Dependent Claim
41 words
A method as claimed in Claim 3, characterised in that the gas mixture supplied to the reactor consists of helium and 2 to 10% by volume of fluorine, to which 0.5 to 2% by volume of CF 3 Br are added.
Claim 6
Independent Claim
29 words
A method as claimed in any of Claims 1, 2 or 3, characterised in that the gas or gas mixture supplied to the reactor comprises N F 3 .