Plasma etching method, plasma etching apparatus, control program, computer recording medium and recording medium having processing recipe recorded thereon
AssigneeTokyo Electron Limited
InventorMasahiro Ogasawara
Life of this patent
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Abstract
In a first step and a thirst step, etching gases are used which contain fluorocarbon gases having C/F atom number ratios higher than that in a second step. A hole is formed to a midpoint in a silicon oxide film in the first step, the hole is formed until a base SiN film begins to be exposed or immediately before it is exposed in the second step, and overetching is performed in the third step. This enables even a hole having a fine diameter and a high aspect ratio to be formed in an excellent shape.
Claims19
A plasma etching method of forming a hole by an etching process in a silicon oxide film through a mask,
- wherein an etching gas containing a fluorocarbon gas is used, and C/F (the number of carbon atoms/the number of fluorine atoms) ratios of a fluorocarbon gas used in an initial period of the etching process and a fluorocarbon gas used in a final period of the etching process are higher than a C/F ratio of a fluorocarbon gas used in an intermediate period of the etching process.
A plasma etching method of forming a hole with a hole diameter of 0.13 μm or smaller in a silicon oxide film formed on a silicon nitride film, comprising:
- a first step of etching the silicon oxide film to a midpoint using an etching gas containing C4F6 or C5F8;
- after said first step, a second step of etching the silicon oxide film using an etching gas containing C4F8;
- and
- after said second step, a third step of performing overetching using an etching gas containing C4F6 or C5F8.
A recording medium having a processing recipe recorded thereon, for controlling a plasma etching apparatus which forms a hole by an etching process in a silicon oxide film through a predetermined mask, the processing recipe, comprising:
- a first etching process of performing etching using an etching gas containing a fluorocarbon gas;
- after said first etching process, a second etching process of performing etching using an etching gas containing a fluorocarbon gas;
- and
- after said second etching process, a third etching process of performing etching using an etching gas containing a fluorocarbon gas, wherein C/F (the number of carbon atoms/the number of fluorine atoms) ratios of the fluorocarbon gases used in said first and third etching processes are higher than a C/F ratio of the fluorocarbon gas used in said second etching process.
A recording medium having a processing recipe recorded thereon, for controlling a plasma etching apparatus which forms a hole by an etching process in a silicon oxide film formed on a silicon nitride film through a predetermined mask, the processing recipe comprising:
- a first step of etching the silicon oxide film to a midpoint using an etching gas containing C4F6 or C5F8;
- after said first step, a second step of etching the silicon oxide film using an etching gas containing C4F8;
- and
- after said second step, a third step of performing overetching using an etching gas containing C4F6 or C5F8.
Dependencies are inferred from the claim text.