Endpoint detection for high density plasma (HDP) processes
First Claim
1. A method of monitoring a plasma process, comprising:
- providing a spectral emission of a first reaction component at a selected wavelength;
providing a spectral emission of a second reaction component at a wavelength in close proximity to the selected wavelength of the first reaction component, wherein the close proximity is between about 1 nm and about 50 nm;
determining a ratio consisting of an intensity of the first reaction component spectral emission and an intensity of the second reaction component spectral emission; and
monitoring the ratio as a function of time to determine an endpoint of the plasma process.
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Abstract
A method and system are provided for endpoint detection of plasma chamber cleaning or plasma etch processes. Optical emission spectroscopy is utilized to determine a spectral emission ratio of two or more light emitting reaction components at wavelengths in close proximity. When a spectral emission ratio or derivative thereof or mathematical function thereof falls below a selected threshold value, the plasma process may be terminated within a calculated time from the threshold value prior to an endpoint value cutoff. Advantageously, the system and methods of the present invention provide real-time, in-situ monitoring of plasma clean or etch processes to optimize the process and avoid under-cleaning or over-cleaning.
89 Citations
27 Claims
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1. A method of monitoring a plasma process, comprising:
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providing a spectral emission of a first reaction component at a selected wavelength;
providing a spectral emission of a second reaction component at a wavelength in close proximity to the selected wavelength of the first reaction component, wherein the close proximity is between about 1 nm and about 50 nm;
determining a ratio consisting of an intensity of the first reaction component spectral emission and an intensity of the second reaction component spectral emission; and
monitoring the ratio as a function of time to determine an endpoint of the plasma process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of monitoring a plasma process, comprising:
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providing a spectral emission of a first reaction component at a selected wavelength;
providing a spectral emission of a second reaction component at a wavelength in close proximity to the selected wavelength of the first reaction component, wherein the close proximity is between about 1 nm and about 50 nm;
determining a ratio consisting of an intensity of the first reaction component spectral emission and an intensity of the second reaction component spectral emission;
determining a first derivative value of the ratio;
monitoring the first derivative value of the ratio as a function of time; and
ending a plasma process before the first derivative value reaches a value of about zero. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification