Method of Feature Exaction from Time-series of Spectra to Control Endpoint of Process
First Claim
1. A method for using a time-series of spectra to identify endpoint of an etch process, comprising,accessing a virtual carpet that is generated from a time-series of spectra for the etch process collected during a training operation;
- running a fabrication etch process on a fabrication wafer, such that while the fabrication etch process is performed portions of a carpet defined from a time-series of spectra is generated for the fabrication etch process;
comparing the portions of the carpet of the fabrication etch process to the virtual carpet; and
processing end pointing of the fabrication etch process when said comparing indicates that a desired metric has been reached for the fabrication wafer.
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Accused Products
Abstract
Methods and systems for using a time-series of spectra to identify endpoint of an etch process. One method includes accessing a virtual carpet that is formed from a time-series of spectra for the etch process collected during a training operation. And, running a fabrication etch process on a fabrication wafer, such that while the fabrication etch process is performed portions of a carpet defined from a time-series of spectral is generated for the fabrication etch process. Then, comparing the portions of the carpet of the fabrication etch process to the virtual carpet. End pointing is processed for the fabrication etch process when said comparing indicates that a desired metric has been reached for the fabrication wafer. In one example, said portions of the carpet include a current frame of captured spectra and at least one previous frame of captured spectra. The portions of the carpet of the fabrication etch process are fitted to the virtual carpet to identify a virtual frame number and associated floating parameters that are used in a correlation to predicted a value for the metric. Further, each of the carpets produced during the training operation and the virtual carpet are defined by a polynomial. The coefficients of the carpets produced during the training operation are a subset of the coefficients of the polynomial of the virtual carpet.
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Citations
23 Claims
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1. A method for using a time-series of spectra to identify endpoint of an etch process, comprising,
accessing a virtual carpet that is generated from a time-series of spectra for the etch process collected during a training operation; -
running a fabrication etch process on a fabrication wafer, such that while the fabrication etch process is performed portions of a carpet defined from a time-series of spectra is generated for the fabrication etch process; comparing the portions of the carpet of the fabrication etch process to the virtual carpet; and processing end pointing of the fabrication etch process when said comparing indicates that a desired metric has been reached for the fabrication wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for generating training data from a time-series of spectra generated during an etching process in a chamber, comprising,
etching a plurality of substrates in one or more chambers, wherein while the etching is processed, capturing a plurality of samples of frames of spectra, each captured frame of spectra identifying an intensity of the spectra as a function of wavelength; -
measuring a metric associated with each substrate after said etching is complete by associating the measured metric to a last frame of spectra of the corresponding substrate; generating a plurality of carpets, one for each of the substrates etched, wherein each of the carpets is defined by the plurality of frames of spectra and a polynomial with corresponding coefficients define characteristics of said each; generating a virtual carpet by processing the plurality of carpets using a polynomial fitting algorithm, the virtual carpet is a superset of the plurality of carpets, such that every one of the plurality of carpets can be projected onto the virtual carpet to determine a virtual frame number in the virtual carpet; correlating the virtual frame numbers of the virtual carpet to a predicted value of the metric; wherein the virtual carpet is accessed by a controller during real-time processing of a substrate in order to determine when a current predicted value of the metric obtained from the virtual carpet corresponds to a predefined value for the metric that is indicative of endpoint of the etching process in the real-time processing. - View Dependent Claims (12, 13, 14, 15, 16, 17, 22)
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18. Computer readable media having program instructions for using a time-series of spectra to identify endpoint of an etch process, comprising,
program instructions for accessing a virtual carpet that is generated from a time-series of spectra for the etch process collected during a training operation; -
program instructions for running a fabrication etch process on a fabrication wafer, such that while the fabrication etch process is performed portions of a carpet defined from a time-series of spectral is generated for the fabrication etch process; program instructions for comparing the portions of the carpet of the fabrication etch process to the virtual carpet; and program instructions for processing end pointing of the fabrication etch process when said comparing indicates that a desired metric has been reached for the fabrication wafer. - View Dependent Claims (19, 20, 21, 23)
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Specification