Dry etching method and method of manufacturing semiconductor apparatus
AssigneeSony Corporation
InventorSeiichi Fukuda
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Abstract
A dry etching method and a method of manufacturing a semiconductor apparatus are disclosed with which satisfactory shape controllability can be obtained and a gate electrode formed by laminating tungsten can be formed without any breakage of a gate insulating film. A polysilicon film, a reaction barrier film made of tungsten nitride, a tungsten film and an offset film made of silicon nitride are sequentially formed on a gate insulating film. Then, a photoresist is used as a mask to etch the tungsten film. The etching process is performed by mixed gas of fluorine gas, chlorine, oxygen and nitrogen.
Claims4
A dry etching method comprising the step of:
- dry-etching a formed film of tungsten through its entire thickness as originally formed using only a single mixed gas including a fluorine-containing gas that includes a compound having fluorine and carbon in a molecule, chlorine or hydrogen bromide, oxygen, and nitrogen,
- wherein said fluorine-containing gas has a structure that a ratio of fluorine atoms with respect to elements of the gas molecule except for fluorine is four or less when the composition of the fluorine molecule is MXFY, Y/X≦4 where M is an element except for fluorine atom and F is fluorine, and the total number of fluorine atoms in elements constituting said gas molecule is four or less.
A method of manufacturing a semiconductor apparatus comprising the steps of:
- laminating upwards a polycrystal silicon film or an amorphous silicon film, a tungsten nitride film or a titanium nitride film, and a tungsten film on a silicon substrate;
- and
- performing a dry-etching of said tungsten nitride film through its entire thickness as originally formed, or said titanium nitride film and said tungsten film through its entire thickness as originally formed, with only a single mixed gas containing fluorine-containing gas that includes a compound having fluorine and carbon in a molecule, chlorine or hydrogen bromide, oxygen and nitrogen so that a gate electrode is formed,
- wherein said fluorine-containing gas has a structure that a ratio of fluorine atoms with respect to elements of the gas molecule except for fluorine is four or less when the composition of the fluorine molecule is MXFY, Y/X≦4 where M is an element except for fluorine atom and F is fluorine, and the total number of fluorine atoms in elements constituting said gas molecule is four or less.
Dependencies are inferred from the claim text.