Full spectrum adaptive filtering (FSAF) for low open area endpoint detection
First Claim
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1. A method of detecting a desired etch state while etching a substrate, the method comprising:
- (a) providing first and second reference spectrums;
(b) detecting optical emissions during etching of the substrate to generate a runtime optical emission spectrum (OES);
(c) comparing the runtime OES with the first and second reference spectrums using adaptive filtering to generate a comparator output; and
(d) repeating (b) and (c) until the desired etch state is detected based on the comparator output.
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Abstract
A method for precise endpoint detection during etch processing of a substrate based on adaptive filtering of the optical emission spectrum (OES) data, even in low open area etching, is provided. Endpoint detection performed in this manner offers the benefits of increased signal-to-noise ratio and decreased computation costs and delay when compared to conventional endpoint detection techniques.
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Citations
9 Claims
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1. A method of detecting a desired etch state while etching a substrate, the method comprising:
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(a) providing first and second reference spectrums; (b) detecting optical emissions during etching of the substrate to generate a runtime optical emission spectrum (OES); (c) comparing the runtime OES with the first and second reference spectrums using adaptive filtering to generate a comparator output; and (d) repeating (b) and (c) until the desired etch state is detected based on the comparator output. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computer-readable medium containing a program for detecting a desired etch state while etching a substrate, which, when executed by a processor, performs operations comprising:
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(a) providing first and second reference spectrums; (b) detecting optical emissions during etching of the substrate to generate a runtime optical emission spectrum (OES); (c) comparing the runtime OES with the first and second reference spectrums using adaptive filtering to generate a comparator output; and (d) repeating (b) and (c) until the desired etch state is detected based on the comparator output. - View Dependent Claims (8, 9)
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Specification