Method and apparatus for detecting endpoint
First Claim
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1. A method for detecting an endpoint of a process in a plasma processing system comprising:
- starting said process in a process chamber;
measuring at least two endpoint signals;
generating at least two filtered endpoint signals by applying a Savitsky Golay filter to said at least two endpoint signals; and
determining an endpoint of said process from said at least two filtered endpoint signals,wherein said at least two filtered endpoint signals comprise a first filtered endpoint signal corresponding to a first chemical constituent found in the process chamber and a second filtered endpoint signal corresponding to a second chemical constituent found in the process chamber,wherein said endpoint is determined from a ratio signal, said ratio signal generated by a ratio of said first filtered endpoint signal and said second filtered endpoint signal,wherein the first filtered signal corresponds to a first chemical constituent whose concentration decays during endpoint, andwherein the second filtered signal corresponds to a second chemical constituent whose concentration rises during endpoint.
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Abstract
The present invention presents a method for detecting an endpoint of an etch process for etching a substrate in plasma processing system (1) comprising: etching the substrate; measuring at least one endpoint signal; generating at least one filtered endpoint signal by filtering the at least one endpoint signal, wherein the filtering comprises applying a Savitsky Golay filter (12) to the at least one endpoint signal; and determining (14) an endpoint of the etch process from the at least one filtered endpoint signal.
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Citations
32 Claims
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1. A method for detecting an endpoint of a process in a plasma processing system comprising:
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starting said process in a process chamber; measuring at least two endpoint signals; generating at least two filtered endpoint signals by applying a Savitsky Golay filter to said at least two endpoint signals; and determining an endpoint of said process from said at least two filtered endpoint signals, wherein said at least two filtered endpoint signals comprise a first filtered endpoint signal corresponding to a first chemical constituent found in the process chamber and a second filtered endpoint signal corresponding to a second chemical constituent found in the process chamber, wherein said endpoint is determined from a ratio signal, said ratio signal generated by a ratio of said first filtered endpoint signal and said second filtered endpoint signal, wherein the first filtered signal corresponds to a first chemical constituent whose concentration decays during endpoint, and wherein the second filtered signal corresponds to a second chemical constituent whose concentration rises during endpoint. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for detecting an endpoint of a process comprising:
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starting said process in a process chamber; measuring a first endpoint signal corresponding to a first chemical constituent found in the process chamber; measuring a second endpoint signal corresponding to a second chemical constituent found in the process chamber; determining a ratio signal from a ratio of said first endpoint signal and said second endpoint signal, said ratio signal comprises an endpoint transition; determining a differential signal from said ratio signal by applying a differential filter to said ratio signal, wherein said differential filter comprises a Savitsky Golay filter; and determining an endpoint of said process from said differential signal, wherein the first filtered signal corresponds to a first chemical constituent whose concentration decays during endpoint, and wherein the second filtered signal corresponds to a second chemical constituent whose concentration rises during endpoint. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A plasma processing system comprising:
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a process chamber; a diagnostic system coupled to said process chamber and configured to measure at least two filtered endpoint signals; and a controller coupled to said diagnostic system, configured to filter said at least two filtered endpoint signals using a Savitsky Golay filter, and configured to determine an endpoint from the filtered endpoint signals, wherein said at least two filtered endpoint signals comprise a first filtered endpoint signal corresponding to a first chemical constituent found in the process chamber and a second filtered endpoint signal corresponding to a second chemical constituent found in the process chamber, wherein said controller is configured to determine said endpoint from a ratio signal, said ratio signal generated by a ratio of said first filtered endpoint signal and said second filtered endpoint signal, wherein the first filtered signal corresponds to a first chemical constituent whose concentration decays during endpoint, and wherein the second filtered signal corresponds to a second chemical constituent whose concentration rises during endpoint. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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Specification