Wafer out-of-pocket detection method

• US 6,274,878 B1
• Filed: 06/06/2000
• Issued: 08/14/2001
• Est. Priority Date: 07/23/1997
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Li, Shih-Hung, Vass, Curtis
• Primary Examiner(s): Lee, John R.
• Application Number:
  US09/588,974
• Time in Patent Office: 434 Days
• Field of Search: 250/221, 250/222.1, 250/559.29, 250/559.3, 250/559.31, 250/559.33, 250/559.38, 250/559.4, 250/548
• US Class Current: 250/548
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection
• CPC Class Codes: H01L 21/681 using optical controlling means

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.

25. The method of claim 10 further comprising providing infrared radiant heat to said 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.

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.