Wafer out-of-pocket detection method

{
  "publication_number": "US6274878B1",
  "country": "US",
  "kind": "B1",
  "title": "Wafer out-of-pocket detection method",
  "abstract": "An apparatus and method for monitoring the inclination of a wafer residing within a pocket of a semiconductor processing chamber susceptor. The apparatus of the present invention includes a laser beam source that is positioned to direct a laser beam onto the top surface of a wafer that has been positioned within a susceptor pocket. A laser receiver is positioned to detect the laser beam after it has been reflected off the surface of the wafer. The laser receiver emits an output signal to a visual or audible indicator that indicates whether or not the wafer is properly positioned within the pocket of the susceptor.",
  "claims": [
    "1. A method of determining the position of a wafer located within a pocket of a semiconductor processing chamber susceptor, said method comprising: focusing a light beam onto the top surface of said wafer; and detecting said light beam directly after said light beam is reflected from the top surface of said wafer when said wafer is positioned substantially horizontally within said pocket.",
    "2. The method of claim 1 wherein said light beam comprises a laser beam.",
    "3. The method of claim 2 wherein said laser beam has a wavelength of less than 680 nanometers.",
    "4. The method of claim 2 wherein said laser beam has a wavelength shorter than that of infrared radiation.",
    "5. The method of claim 1 further comprising producing a signal representative of said detected light beam.",
    "6. The method of claim 5 wherein said signal is received by a wafer inclination indicator.",
    "7. The method of claim 6 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor.",
    "8. The method of claim 6 further comprising providing a visual alarm when said signal is not received by said wafer inclination indicator.",
    "9. The method of claim 6 further comprising providing an audible alarm when said signal is not received by said wafer inclination indicator.",
    "10. The method of claim 6 further comprising providing a visual alarm when said signal is not received by said wafer inclination indicator.",
    "11. The method of claim 6 further comprising providing an audible alarm when said signal is not received by said wafer inclination indicator.",
    "12. The method of claim 5 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor.",
    "13. The method of claim 1 wherein said light beam has a wavelength within the range of about 500 to about 600 nanometers.",
    "14. The method of claim 1 wherein said susceptor is in a high temperature processing chamber and said detecting is performed during high temperature processing.",
    "15. The method of claim 14 further comprising providing infrared radiant heat to said high temperature processing chamber.",
    "16. A method of determining the position of a wafer located with in a pocket of a susceptor in a semiconductor processing chamber, said method comprising: heating said chamber and said wafer above about 600 degrees Celsius; focusing a light beam onto the top surface of said wafer; and detecting said light beam while said chamber is heated and directly after said light beam is reflected from the top surface of said wafer when said wafer is positioned substantially horizontally within said pocket.",
    "17. The method of claim 16 wherein said light beam comprises a laser beam.",
    "18. The method of claim 17 wherein said laser beam has a wavelength of less than 680 nanometers.",
    "19. The method of claim 17 wherein said laser beam has a wavelength shorter than that of infrared radiation.",
    "20. The method of claim 16 wherein said light beam has a wavelength within the range of about 500 to about 600 nanometers.",
    "21. The method of claim 16 further comprising producing a signal representative of said detected light beam.",
    "22. The method of claim 21 wherein said signal is received by a wafer inclination indicator.",
    "23. The method of claim 22 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor.",
    "24. The method of claim 21 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor.",
    "25. The method of claim 10 further comprising providing infrared radiant heat to said chamber.",
    "26. A method of determining the position of a wafer located within a pocket of a susceptor in a semiconductor processing chamber, the method comprising: providing infrared radiant heat to said chamber; focusing a laser beam onto the top surface of the wafer; and detecting said laser beam directly after said laser beam is reflected from the top surface of the wafer when said wafer is positioned substantially horizontally within said pocket.",
    "27. The method of claim 26 wherein said laser beam has a wavelength of less than 680 nanometers.",
    "28. The method of claim 26 wherein said laser beam has a wavelength within the range of about 500 to about 600 nanometers.",
    "29. The method of claim 26 wherein said laser beam has a wavelength shorter than that of infrared radiation.",
    "30. The method of claim 26 further comprising producing a signal representative of said detected laser beam.",
    "31. The method of claim 30 wherein said signal is received by a wafer position indicator.",
    "32. The method of claim 31 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor.",
    "33. The method of claim 31 further comprising providing a visual alarm when said signal is not received by said wafer position indicator.",
    "34. The method of claim 31 further comprising providing an audible alarm when said signal is not received by said wafer position indicator.",
    "35. The method of claim 30 wherein said signal is received by a controller of an automated wafer handling system, said wafer handling system positioning said wafer within said pocket of said susceptor."
  ],
  "description_excerpt": "This application is a divisional of application No. Ser. 08/899,631, filed Jul. 23, 1997, now U.S. Pat. No. 6,099,596.\n\nThe present invention relates generally to semiconductor processing and particularly to a tool for detecting the position of a wafer in a semiconductor processing chamber.\n\nDeposition of a film on the surface of a semiconductor wafer is a common step in semiconductor processing. The process of depositing layers on a semiconductor wafer (or substrate) usually involves placing the substrate within a processing chamber and holding the wafer within a stream of a reactant gas flowing across the surface of a wafer. Usually, heat is applied to drive the chemical reaction of the gases in the chamber and to heat the surface of the wafer on which the film is deposited. The processing chamber is typically heated by external lamps which pass infra-red radiation into the processing chamber through a quartz window that is transparent to the infra-red radiation.\n\nReferring now to FIG. 1, there is shown a multiple-chamber integrated process system 100 including an enclosed main frame or housing 102 having sidewalls that define an enclosed vacuum transfer chamber 104.\n\nA number of individual processing chambers 106 a-f are mounted one each on an associated sidewall of the transfer chamber 104. Two load lock cassette elevators 108 a and 108 b are adapted for vertically stacking a multiplicity of cassettes which in turn hold wafers 110 horizontally.",
  "cpc": [
    "H10P 72/0606",
    "H10P 72/53",
    "H10P 74/00"
  ],
  "ipc": [
    "H10P 14/24",
    "H10P 72/50",
    "H10P 95/00"
  ],
  "assignees": [
    "Applied Materials Inc"
  ],
  "inventors": [
    "Shih-Hung Li",
    "Curtis Vass"
  ],
  "filing_date": "2000-06-06",
  "publication_date": "2001-08-14",
  "grant_date": "2001-08-14",
  "priority_date": "1997-07-23",
  "application_number": "US-58897400-A",
  "family_id": "25411328",
  "cited_by_count": 593,
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}