Method and system employing optical emission spectroscopy for monitoring and controlling semiconductor fabrication
First Claim
1. An automated method for operating a semiconductor manufacturing apparatus within predefined or derived limits, said apparatus having a fabrication chamber with at least one of a flow rate controllable gaseous species inlet, an adjustable radio frequency powering means and a pressure adjustment mechanism, said automated method comprising the steps of:
- (a) producing a plasma process within said fabrication chamber of said semiconductor manufacturing apparatus;
(b) simultaneous with said step (a), collecting from within said chamber wavelength and relative intensity data on a plurality of different electromagnetic wavelengths simultaneously occurring therein;
(c) determining the location of at least some intensity peaks for the simultaneously occurring plurality of different electromagnetic wavelengths from said wavelength and relative intensity data;
(d) utilizing said wavelength data collected in step (b) and said intensity peak location information determined in step (c) to identify using a Markov random field model at least one gaseous species contained within said chamber during said plasma processing; and
(e) regulating in an automated manner said plasma process of step (a) to ensure operation of semiconductor manufacturing apparatus within said predefined or derived limits, said regulating being based on information determined in said steps (b)-(d), said regulating step including automatically regulating said plasma process of step (a) through control of one of said at least one flow rate controllable gaseous species inlet, said adjustable radio frequency powering means and said pressure adjustment mechanism associated with said fabrication chamber.
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Abstract
Automated, closed loop method and system for monitor and control of semiconductor fabrication processing are described. Optical emissions spectrometer (OES) data readings from a fabrication plasma chamber are statistically analyzed and a novel pattern model (based on Markov random fields) is used in combination with a selective stochastic relaxation technique to identify gaseous species within the chamber from the OES readings. Wavelength and intensity information is also employed to accurately estimate relative concentration levels of identified gases within the chamber. The unique statistical analysis approach described allows real-time monitor and control of physical processing within the fabrication chamber. Several practical algorithms are set forth, including techniques for OES peak identification, peak sharpening, gas identification, and physical processing control.
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Citations
40 Claims
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1. An automated method for operating a semiconductor manufacturing apparatus within predefined or derived limits, said apparatus having a fabrication chamber with at least one of a flow rate controllable gaseous species inlet, an adjustable radio frequency powering means and a pressure adjustment mechanism, said automated method comprising the steps of:
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(a) producing a plasma process within said fabrication chamber of said semiconductor manufacturing apparatus; (b) simultaneous with said step (a), collecting from within said chamber wavelength and relative intensity data on a plurality of different electromagnetic wavelengths simultaneously occurring therein; (c) determining the location of at least some intensity peaks for the simultaneously occurring plurality of different electromagnetic wavelengths from said wavelength and relative intensity data; (d) utilizing said wavelength data collected in step (b) and said intensity peak location information determined in step (c) to identify using a Markov random field model at least one gaseous species contained within said chamber during said plasma processing; and (e) regulating in an automated manner said plasma process of step (a) to ensure operation of semiconductor manufacturing apparatus within said predefined or derived limits, said regulating being based on information determined in said steps (b)-(d), said regulating step including automatically regulating said plasma process of step (a) through control of one of said at least one flow rate controllable gaseous species inlet, said adjustable radio frequency powering means and said pressure adjustment mechanism associated with said fabrication chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A closed loop method for monitoring and controlling a plasma process, said method comprising the steps of:
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(a) providing a plasma processing system having a fabrication chamber with at least one electronically adjustable control for regulating plasma processing within said chamber; (b) establishing a plasma process within said fabrication chamber; (c) simultaneous with said step (b), collecting an electromagnetic wavelength spectra from said plasma process occurring within said fabrication chamber, said collected spectra comprising wavelength and relative intensity data; (d) determining an intensity peak location for each of at least some of said different electromagnetic wavelengths in said wavelength data; (e) utilizing said wavelength and relative intensity data of step (c) and said peak location information of step (d) to identify using a Markov random field model at least one vaporized species contained within said chamber; and (f) regulating in an automated manner said plasma processing of step (b) based on said wavelength and relative intensity data, peak location information and vaporized species information of said steps (c)-(e), respectively, said plasma process regulating including producing an electronic signal to automatically regulate said at least one adjustable control associated with said fabrication chamber, and thereby regulate said plasma processing occurring therein. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A closed loop method for operating a semiconductor fabrication chamber within predefined or derived constraints, said fabrication chamber having at least one electronically adjustable mechanism for controlling processing therein, said operating method comprising the steps of:
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(a) establishing a plasma process within said fabrication chamber; (b) simultaneous with said step (a), collecting multivariate data indicative of gaseous species occurring in said plasma process established in step (a) within said chamber, said multivariate data being collected through at least one sensor associated with said fabrication chamber; (c) using said collected multivariate data of step (b) to identify in real-time using a Markov random field model a gaseous species contained within said chamber, and its relative concentration level; and (d) automatically regulating said plasma process within said fabrication chamber in real-time based on said identified gaseous species and its determined relative concentration level of said step (c), said regulating step including producing an electronic signal to adjust said at least one adjustable mechanism based upon the multivariate data collected and the relative concentration information determined in said steps (b) and (c), respectively, whenever plasma processing exceeds said predefined or derived constraints, said adjusting being such as to bring said plasma process within said predefined or derived constraints. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. An automated method for operating and controlling within predefined or derived limits a plasma processing system having a fabrication chamber with at least one electronically adjustable, primary plasma process control point, said automated method comprising the steps of:
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(a) producing a plasma process within said fabrication chamber; (b) collecting optical emission spectra data on said plasma process occurring within said fabrication chamber; (c) locating intensity peaks in said optical emission spectra data; (d) electronically identifying using a Markov random field model gaseous species contained within said chamber during said plasma processing based on said optical emission spectra data of step (b); (e) determining whether any incorrect gaseous species is identified in said step (d) for said plasma process of step (a); and (f) whenever said step (e) identifies an incorrect gaseous species, regulating in an automated manner said plasma processing by producing an electronic control signal to adjust said primary process control point to move said plasma processing of step (a) within said predefined or derived limits. - View Dependent Claims (29, 30)
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31. A closed loop system for manufacturing a semiconductor, said closed loop system comprising:
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semiconductor manufacturing apparatus including a fabrication chamber and apparatus for generating a plasma process therein; at least one electronically adjustable mechanism for controlling plasma processing within said fabrication chamber; means, associated with said fabrication chamber, for collecting an electromagnetic wavelength spectra from within said fabrication chamber while plasma processing is occurring therein, said collected spectra comprising wavelength and relative intensity data; means for determining an intensity peak location for at least some of the different electromagnetic wavelengths represented by said wavelength data; processor means coupled to said collecting means and said determining means for automatically identifying using a Markov random field model at least one vaporized species contained within said chamber during plasma processing using said wavelength and relative intensity data and said intensity peak location information; and real-time feedback control means responsive to said processor means for regulating within predetermined limits said plasma processing occurring within said fabrication chamber based on said wavelength and relative intensity data, located peak information and identified vaporized species, said feedback control means being coupled to said at least one electronically adjustable mechanism and including means for electronically adjusting said at least one adjustable mechanism to maintain said plasma processing occurring within said fabrication chamber within said predetermined limits. - View Dependent Claims (32, 33)
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34. An automated method for operating within predefined or derived limits a plasma processing system having a fabrication chamber with at least one electronically adjustable, primary plasma process control point, comprising the steps of:
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(a) producing a plasma process within the fabrication chamber; (b) simultaneous with said step (a), collecting optical emission spectra data on said plasma process produced within the fabrication chamber; (c) locating intensity peaks in said optical emission spectra data collected in said step (b); (d) sharpening at least some of said located intensity peaks of said step (c); and (e) electronically identifying at least one gaseous species contained within the fabrication chamber during said plasma processing using said intensity peaks sharpened in said step (d). - View Dependent Claims (35, 36, 37, 38, 39)
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40. A method for identifying at least one gaseous species present in a process, said method comprising the steps of:
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(a) generating wavelength and relative intensity data from the process using an optical emissions spectrometer; (b) providing a Markov random field model correlating wavelength and relative intensity data with particular gaseous species; and (c) electronically identifying at least one gaseous species contained within the process by employing the Markov random field model of step (b) and the generated wavelength and relative intensity data of step (a).
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Specification