Etching method
AssigneeTokyo Electron Limited
InventorsMasahiro Tabata, Takayuki Katsunuma, Masanobu Honda
Life of this patent
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Abstract
A method for selectively etching a first region of silicon oxide with respect to a second region of silicon nitride, includes: preparing a target object including the first region and the second region in a processing chamber of a plasma processing apparatus; and generating a plasma of a processing gas containing a fluorocarbon gas and a rare gas in the processing chamber. In the generating the plasma of the processing gas, a self-bias potential of a lower electrode on which the target object is mounted is greater than or equal to 4V and smaller than or equal to 350V and a flow rate of the rare gas in the processing gas is 250 to 5000 times of a flow rate of the fluorocarbon gas in the processing gas.
Claims11
A method for selectively etching a first region of silicon oxide with respect to a second region of silicon nitride, the method comprising:
- preparing a target object including the first region, the second region, and an organic film in a processing chamber of a plasma processing apparatus, wherein the first region covers the second region, and the organic film covers the first region and includes amorphous carbon;
- etching the organic film by generating a first plasma of a first processing gas including hydrogen gas and nitrogen gas;
- and
- etching the first region by generating a second plasma of a second processing gas containing a fluorocarbon gas and a rare gas in the processing chamber,
- wherein in said generating the plasma of the second processing gas, a self-bias potential of a lower electrode on which the target object is mounted is greater than or equal to 4V and smaller than or equal to 350V and a volumetric flow rate of the rare gas in the second processing gas is 250 to 5000 times of a volumetric flow rate of the fluorocarbon gas in the second processing gas,
- wherein the second region forms a recess and the first region fills the recess and covers the second region,
- the method further comprising:
- after the step of etching the first region by generating the second plasma, executing a sequence one or more times to further etch the first region in a period including a time when the second region is exposed,
- wherein the sequence includes:
- generating a third plasma of a third processing gas including a fluorocarbon gas in the processing chamber and forming a deposit containing fluorocarbon on the first region and the second region;
- and
- generating a fourth plasma of an inert gas in the processing chamber.
A method for selectively etching a first region of silicon oxide with respect to a second region of silicon nitride, the method comprising:
- preparing a target object including the first region, the second region, and an organic film in a processing chamber of a plasma processing apparatus, wherein the first region covers the second region, and the organic film covers the first region and includes amorphous carbon;
- etching the organic film by generating a first plasma of a first processing gas including hydrogen gas and nitrogen gas;
- and
- etching the first region by generating a second plasma of a second processing gas containing a fluorocarbon gas and a rare gas in the processing chamber,
- wherein in said generating the plasma of the second processing gas, a self-bias potential of a lower electrode on which the target object is mounted is greater than or equal to 4V and smaller than or equal to 350V and a volumetric flow rate of the rare gas in the second processing gas is 250 to 5000 times of a volumetric flow rate of the fluorocarbon gas in the second processing gas,
- wherein in said generating the plasma of the second processing gas, in order to supply the second processing gas into the processing chamber, a gaseous mixture of a fluorocarbon gas and a rare gas is supplied from a single gas source into the processing chamber.
A method for selectively etching a first region of silicon oxide with respect to a second region of silicon nitride, the method comprising:
- preparing a target object including the first region and the second region in a processing chamber of a plasma processing apparatus, the first region covering the second region;
- etching the first region until immediately before the second region is exposed by generating a first plasma of a first processing gas including a first fluorocarbon gas;
- after the step of etching the first region, executing a sequence one or more times to further etch the first region in a period including a time when the second region is exposed,
- wherein the sequence includes:
- generating a second plasma of a second processing gas including a second fluorocarbon gas in the processing chamber and forming a deposit containing fluorocarbon on the first region and the second region;
- generating a third plasma of a third processing gas including an inert gas in the processing chamber;
- and
- generating a fourth plasma of a fourth processing gas including the second fluorocarbon gas and a rare gas to further etch the first region,
- wherein in said generating the fourth plasma of the fourth processing gas including the third fluorocarbon gas and the rare gas, a self-bias potential of a lower electrode on which the target object is mounted is greater than or equal to 4V and smaller than or equal to 350V and a volumetric flow rate of the rare gas in the processing gas is 250 to 5000 times of a volumetric flow rate of the third fluorocarbon gas in the processing gas, and
- wherein the first fluorocarbon gas includes C4F8 gas, and the second fluorocarbon gas includes C4F6 gas.
Dependencies are inferred from the claim text.