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US 10,854,463 B2Granted
Etching method and method for manufacturing DRAM capacitor
AssigneeTokyo Electron Limited
InventorNobuhiro Takahashi
Life of this patent
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Abstract
There is provided an etching method which includes: preparing a target substrate having a silicon portion, a silicon nitride film and a silicon oxide film; and selectively etching the silicon portion with respect to the silicon nitride film and the silicon oxide film by supplying a fluorine-containing gas and an inert gas which stay in an excited state to the target substrate.
Claims15
An etching method, comprising:
- preparing a target substrate including a silicon portion, a Ti-based film, a silicon nitride film formed on a surface of the silicon portion to support the Ti-based film, and a silicon oxide film;
- and
- selectively etching the silicon portion with respect to the Ti-based film, the silicon nitride film, and the silicon oxide film by supplying a fluorine-containing gas and an inert gas maintained in an excited state to the target substrate so that the Ti-based film is allowed to remain while being supported by the silicon nitride film,
- wherein the inert gas is a gas selected from a group consisting of an N2 gas and noble gases.
1 more element
A method for manufacturing a DRAM capacitor, comprising:
- preparing a semiconductor wafer having a structure in which an underlying silicon oxide film is formed on a semiconductor substrate, a sacrificial polysilicon film is formed on the silicon oxide film, a plurality of columnar recesses is formed in the sacrificial polysilicon film, a plurality of cylindrical TiN films serving as lower electrodes are formed in the respective columnar recesses and a silicon nitride film for supporting the cylindrical TiN films is formed on the sacrificial polysilicon film;
- and
- selectively etching the sacrificial polysilicon film by supplying a hydrogen fluoride gas and an inert gas which are maintained in an excited state to the semiconductor wafer so that the plurality of cylindrical TiN films are allowed to remain as the lower electrodes for DRAM capacitors supported by the silicon nitride film,
- wherein the inert gas is a gas selected from a group consisting of an N2 gas and noble gases.
1 more element
Dependencies are inferred from the claim text.