Method and apparatus for detecting plasma unconfinement
First Claim
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1. A method for detecting plasma unconfinement in a reaction chamber during a bevel edge cleaning operation, comprising:
- selecting wavelengths associated with expected byproducts of a bevel edge clean process;
cleaning the bevel edge area of a substrate through a plasma confined to a region proximate to the bevel edge area;
monitoring the selected wavelengths originating within the chamber during the cleaning for deviation from a wavelength intensity value stored in an external controller, the deviation based on an averaged difference between a maximum wavelength and a minimum wavelength measured over a time period; and
terminating the cleaning if the deviation from the wavelength intensity value exceeds a target deviation, wherein the deviation from the wavelength intensity value exceeding the target deviation indicates an unconfined condition where the plasma extends outside the region proximate to the bevel edge area.
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Abstract
A method for detecting plasma unconfinement in a reaction chamber during a bevel edge cleaning operation is provided. The method initiates with selecting a wavelength associated with expected by products of a bevel edge clean process. The method includes cleaning the bevel edge area of a substrate and monitoring the intensity of the selected wavelengths during the cleaning for deviation from a threshold wavelength intensity. The cleaning is terminated if the deviation from the threshold wavelength intensity exceeds a target deviation.
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Citations
18 Claims
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1. A method for detecting plasma unconfinement in a reaction chamber during a bevel edge cleaning operation, comprising:
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selecting wavelengths associated with expected byproducts of a bevel edge clean process; cleaning the bevel edge area of a substrate through a plasma confined to a region proximate to the bevel edge area; monitoring the selected wavelengths originating within the chamber during the cleaning for deviation from a wavelength intensity value stored in an external controller, the deviation based on an averaged difference between a maximum wavelength and a minimum wavelength measured over a time period; and terminating the cleaning if the deviation from the wavelength intensity value exceeds a target deviation, wherein the deviation from the wavelength intensity value exceeding the target deviation indicates an unconfined condition where the plasma extends outside the region proximate to the bevel edge area. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for preventing plasma unconfinement from an edge region of a substrate in a reaction chamber during an edge cleaning process, comprising:
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processing a semiconductor substrate in a processing chamber, the processing depositing byproducts on a peripheral edge of the substrate; performing an edge cleaning process to remove the deposited byproducts, the edge cleaning process including, striking a plasma confined to a peripheral edge region of the substrate; monitoring confinement of the plasma to the peripheral edge region, the monitoring performed through a single window embedded into a sidewall of the reaction chamber proximate to the peripheral edge region, the monitoring including, tracking a wavelength signal originated within the chamber during the edge cleaning process; and determining whether the plasma remains confined to the peripheral edge region based on fluctuation of an averaged difference between a maximum wavelength and a minimum wavelength measured over a time period of the tracked wavelength signal relative to a wavelength intensity value stored in an external controller. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for detecting plasma unconfinement in a reaction chamber during a bevel edge cleaning operation, comprising:
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selecting wavelengths associated with expected byproducts of a bevel edge clean process; cleaning the bevel edge area of a substrate through a plasma confined to a region proximate to the bevel edge area; monitoring the selected wavelengths originating within the chamber during the cleaning for deviation from a wavelength intensity value stored in an external controller, the deviation based on a ratio of a difference and an average wavelength, the difference between a maximum wavelength and a minimum wavelength, the maximum wavelength, the minimum wavelength, and the average wavelength measured over a time period; and terminating the cleaning if the deviation from the wavelength intensity value exceeds a target deviation, wherein the deviation from the wavelength intensity value exceeding the target deviation indicates an unconfined condition where the plasma extends outside the region proximate to the bevel edge area.
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Specification