Etching method and method for producing semiconductor element
Provided is an etching method capable of selectively etching an etching object containing silicon nitride as compared with a non-etching object while the generation of particles and a variation in etching rate are suppressed. The etching method includes an etching step of bringing an etching gas containing more than 20% by volume of nitrosyl fluoride into contact with a member to be etched ( 12 ) having an etching object that is to be etched by the etching gas and having a non-etching object that is not to be etched by the etching gas, to selectively etch the etching object as compared with the non-etching object without plasma. The etching object contains silicon nitride.
1 . An etching method comprising:
an etching step of bringing an etching gas containing 30% or more by volume of nitrosyl fluoride into contact with a member to be etched having an etching object that is to be etched by the etching gas and having a non-etching object that is not to be etched by the etching gas, to selectively etch the etching object as compared with the non-etching object without plasma, wherein,
the etching object contains silicon nitride,
and the etching gas is a gas exclusively containing nitrosyl fluoride or a mixed gas containing nitrosyl fluoride and a dilution gas.
2 . The etching method according to claim 1 , wherein the non-etching object is at least one of silicon oxide and amorphous carbon.
3 . The etching method according to claim 2 , wherein in the etching step, a temperature condition is 50° C. or more and 250° C. or less.
4 . The etching method according to claim 1 , wherein an etching selectivity that is a ratio of an etching rate of the etching object to an etching rate of the non-etching object is 10 or more.
5 . A method for producing a semiconductor element, the method using the etching method according to claim 1 to produce a semiconductor element, wherein,
the member to be etched is a semiconductor substrate having the etching object and the non-etching object, and
the method comprises a processing step of removing at least a part of the etching object from the semiconductor substrate by the etching.
6 . The etching method according to claim 2 , wherein an etching selectivity that is a ratio of an etching rate of the etching object to an etching rate of the non-etching object is 10 or more.
7 . The etching method according to claim 3 , wherein an etching selectivity that is a ratio of an etching rate of the etching object to an etching rate of the non-etching object is 10 or more.
8 . A method for producing a semiconductor element, the method using the etching method according to claim 2 to produce a semiconductor element, wherein,
the member to be etched is a semiconductor substrate having the etching object and the non-etching object, and
the method comprises a processing step of removing at least a part of the etching object from the semiconductor substrate by the etching.
9 . A method for producing a semiconductor element, the method using the etching method according to claim 3 to produce a semiconductor element, wherein,
the member to be etched is a semiconductor substrate having the etching object and the non-etching object, and
the method comprises a processing step of removing at least a part of the etching object from the semiconductor substrate by the etching.
10 . A method for producing a semiconductor element, the method using the etching method according to claim 4 to produce a semiconductor element, wherein,
the member to be etched is a semiconductor substrate having the etching object and the non-etching object, and
the method comprises a processing step of removing at least a part of the etching object from the semiconductor substrate by the etching.
11 . The etching method according to claim 1 , wherein the etching gas contains nitrosyl fluoride at 33.3% by volume or more.