In-situ etch rate determination for chamber clean endpoint
First Claim
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1. A method of endpoint detection, comprising:
- performing a first plasma cleaning process in a clean chamber environment;
determining first etch rates at two or more time intervals during the first plasma cleaning process;
determining a first slope defined by the two or more time intervals, wherein the first slope defines the first etch rates as a function of time;
performing a second plasma cleaning process in an unclean chamber environment;
determining second etch rates at two or more time intervals during the second plasma cleaning process;
determining a second slope defined by the two or more time intervals, wherein the second slope defines the second etch rates as a function of time; and
comparing the first slope and the second slope to determine a clean endpoint time.
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Abstract
Embodiments described herein relate to methods for determining a cleaning endpoint. A first plasma cleaning process may be performed in a clean chamber environment to determine a clean time function defined by a first slope. A second plasma cleaning process may be performed in an unclean chamber environment to determine a clean time function defined by a second slope. The first and second slope may be compared to determine a clean endpoint time.
8 Citations
20 Claims
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1. A method of endpoint detection, comprising:
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performing a first plasma cleaning process in a clean chamber environment; determining first etch rates at two or more time intervals during the first plasma cleaning process; determining a first slope defined by the two or more time intervals, wherein the first slope defines the first etch rates as a function of time; performing a second plasma cleaning process in an unclean chamber environment; determining second etch rates at two or more time intervals during the second plasma cleaning process; determining a second slope defined by the two or more time intervals, wherein the second slope defines the second etch rates as a function of time; and comparing the first slope and the second slope to determine a clean endpoint time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of endpoint detection, comprising:
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performing a first plasma cleaning process in a clean chamber environment; determining first etch rates at two or more time intervals during the first plasma cleaning process; determining a first slope defined by the two or more time intervals, wherein the first slope defined the first etch rates as a function of time; performing a second plasma cleaning process in an unclean chamber environment; determining second etch rates at two or more time intervals during the second plasma cleaning process; determining a second slope defined by the two or more time intervals, wherein the second slope defines the second etch rates as a function of time; determining an endpoint time range defined by the two or more time intervals; and comparing the first slope and the second slope within the endpoint time range to determine a clean endpoint time at a point where the first slope and the second slope are substantially equal. - View Dependent Claims (12, 13, 14)
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15. A method of endpoint detection, comprising:
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performing a first cleaning process in a clean chamber environment; determining a first etch rate for the first cleaning process; performing a second cleaning process in the clean chamber environment; determining a second etch rate for the second cleaning process, wherein the first etch rate and the second etch rate define a first slope; performing a third cleaning process in an unclean chamber environment; determining a third etch rate of the third cleaning process; performing a fourth cleaning process in the unclean chamber environment; determining a fourth etch rate of the fourth cleaning process, wherein the third etch rate and the fourth etch rate define a second slope within about 2% of the first slope; and determining a clean endpoint time where the first slope and the second slope are substantially equal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification