Method and apparatus for monitoring plasma processing operations

• US 6,246,473 B1
• Filed: 04/23/1998
• Issued: 06/12/2001
• Est. Priority Date: 04/23/1998
• Status: Expired due to Fees

• Current Assignee: Sandia Corporation (Martin Marietta Corporation)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Ward, Pamela Peardon Denise, Smith, Michael Lane Jr., Stevenson, Joel OʼDon
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): SMITH, ZANDRA V
• Application Number:
  US09/064,991
• Time in Patent Office: 1,146 Days
• Field of Search: 356/316, 356/318, 216/60, 250/844, 219/121.6, 219/121
• US Class Current: 356/316
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/443 Emission spectrometry

Abstract

The invention generally relates to various aspects of a plasma process, and more specifically the monitoring of such plasma processes. One aspect relates in at least some manner to calibrating or initializing a plasma monitoring assembly. This type of calibration may be used to address wavelength shifts, intensity shifts, or both associated with optical emissions data obtained on a plasma process. A calibration light may be directed at a window through which optical emissions data is being obtained to determine the effect, if any, that the inner surface of the window is having on the optical emissions data being obtained therethrough, the operation of the optical emissions data gathering device, or both. Another aspect relates in at least some manner to various types of evaluations which may be undertaken of a plasma process which was run, and more typically one which is currently being run, within the processing chamber. Plasma health evaluations and process identification through optical emissions analysis are included in this aspect. Yet another aspect associated with the present invention relates in at least some manner to the endpoint of a plasma process (e.g., plasma recipe, plasma clean, conditioning wafer operation) or discrete/discernible portion thereof (e.g., a plasma step of a multiple step plasma recipe). A final aspect associated with the present invention relates to how one or more of the above-noted aspects may be implemented into a semiconductor fabrication facility, such as the distribution of wafers to a wafer production system.

Claims

1. A method for monitoring a plasma process conducted within a processing chamber, said method comprising the steps of:

loading a quantity of product into said processing chamber;

obtaining optical emissions from within said processing chamber;

evaluating an output of said obtaining optical emissions step through a first computer;

generating a plasma in said processing chamber;

conducting a plasma process on said product in said processing chamber using said generating step;

evaluating said conducting step with a plasma monitoring assembly;

calibrating said plasma monitoring assembly;

identifying an information of said generating step through said evaluating step; and

terminating said calibrating step upon any execution of said generating step based upon a signal from said identifying step.

2. A method, as claimed in claim 1, wherein said processing chamber comprises a window, and wherein:

said obtaining step comprises collecting at least a portion of said optical emissions passing through said window with a fiber optic cable and providing said at least a portion of said optical emissions to a first spectrometer.

3. A method, as claimed in claim 1, wherein said evaluating step comprises evaluating said output from said obtaining step at a plurality of different times, and wherein said identifying step comprises:

comparing said output at each of said plurality of different times with a predetermined output; and

determining when at least one of said outputs from said comparing step is greater than said predetermined output.

4. A method, as claimed in claim 1, wherein said evaluating step comprises evaluating said output from said obtaining step at a plurality of different times, and wherein said identifying step comprises:

comparing said output at each of said plurality of different times with said output at an earlier of said plurality of different times; and

determining when said outputs from said comparing step differ by more than a predetermined amount.

5. A method, as claimed in claim 1, wherein said evaluating step comprises evaluating said output from said obtaining step at a plurality of different times, and wherein said identifying step comprises:

evaluating said output at each of said plurality of different times; and

determining if any of said outputs from said comparing step include at least predetermined number of discrete intensity peaks having an intensity greater than a predetermined amount.

6. A method, as claimed in claim 1, wherein said processing chamber comprises a window, said method further comprising the steps of:

monitoring a condition of said window; and

automatically terminating said monitoring step upon any initiation of said generating step based upon a signal from said identifying step.

7. A method, as claimed in claim 6, further comprising the step of:

making at least one adjustment in relation to said plasma monitoring assembly based upon an output from said monitoring a condition step.

8. A plasma monitoring system, comprising:

a processing chamber;

means for obtaining optical emissions from within said processing chamber;

means for evaluating an output of said means for obtaining, said means for evaluating comprising a first computer, wherein said means for evaluating comprises a plasma monitoring assembly;

means for calibrating at least a portion of said plasma monitoring assembly;

means for generating a plasma in said processing chamber;

means for identifying activation of said means for generating, said means for identifying comprising said means for evaluating; and

means for disabling said means for calibrating automatically upon activation of means for generating based upon a signal from said means for identifying.

9. A system, as claimed in claim 8, wherein said processing chamber comprises a window, and wherein:

said means for obtaining comprises a first spectrometer and a fiber optic cable which operatively interconnects said window and said first spectrometer.

10. A system, as claimed in claim 8, wherein:

said means for evaluating comprises means for evaluating said output from said means for obtaining at a plurality of different times, and wherein said means for identifying comprises;

means for comparing each said output provided to said means for evaluating with a predetermined output; and

means for determining when any said output from said means for comparing is greater than said predetermined output.

11. A system, as claimed in claim 8, wherein:

said means for evaluating comprises means for evaluating said output from said means for obtaining at a plurality of different times, and wherein said means for identifying comprises;

means for comparing said output at each of said plurality of different times with said output at an earlier of said plurality of different times; and

means for determining when said outputs from said means for comparing differ by more than a predetermined amount.

12. A system, as claimed in claim 8, wherein:

said means for evaluating comprises means for evaluating said output from said means for obtaining at a plurality of different times, and wherein said means for identifying comprises;

means for evaluating said output at each of said plurality of different times; and

means for determining if any of said outputs from said means for evaluating said output include at least predetermined number of discrete intensity peaks having an intensity greater than a predetermined amount.

13. A system, as claimed in claim 8, wherein said processing chamber comprises a window, and wherein said system further comprises:

means for monitoring a condition of said window; and

means for disabling said means for monitoring automatically upon activation of means for generating based upon a signal from said means for identifying.

14. A system, as claimed in claim 13, further comprising:

means for making at least one adjustment in relation to said plasma monitoring assembly based upon an output from means for monitoring.

15. A plasma monitoring system for a plasma process performed on a first product in a processing chamber, said system comprising:

a plasma monitoring assembly;

means for generating a plasma within said processing chamber; and

a computer-readable storage medium comprising;

means for receiving data representative of optical emissions within said processing chamber;

means for evaluating said data provided to said means for receiving, said plasma monitoring assembly comprising said means for evaluating;

means for calibrating at least a portion of said plasma monitoring assembly;

means for identifying when plasma first exists in said processing chamber, said means for identifying comprising said means for evaluating; and

means for disabling said means for calibrating automatically upon activation of said means for generating based upon a signal from said means for identifying.

16. A system, as claimed in claim 15, wherein:

said means for receiving comprises means for receiving data representative of optical emissions within said processing chamber at a plurality of different times, wherein said means for evaluating comprises means for evaluating said output at each of said plurality of different times, and wherein said means for identifying comprises;

means for comparing each said output provided to said means for evaluating with a predetermined output; and

means for determining when any said output from said means for comparing is greater than said predetermined output.

17. A system, as claimed in claim 15, wherein:

said means for receiving comprises means for receiving data representative of optical emissions within said processing chamber at a plurality of different times, wherein said means for evaluating comprises means for evaluating said output at each of said plurality of different times, and wherein said means for identifying comprises;

means for comparing said output at each of said plurality of different times with said output at an earlier of said plurality of different times; and

means for determining when said outputs from said means for comparing differ by more than a predetermined amount.

18. A system, as claimed in claim 15, wherein:

said means for evaluating comprises means for evaluating said output from said means for obtaining at a plurality of different times, and wherein said means for identifying comprises;

means for evaluating said output at each of said plurality of different times; and

means for determining if any of said outputs from said means for evaluating said output include at least predetermined number of discrete intensity peaks having an intensity greater than a predetermined amount.

19. A system, as claimed in claim 15, wherein said processing chamber further comprises a window, said computer-readable storage medium further comprising:

means for monitoring a condition of said window; and

means for disabling said means for monitoring automatically upon activation of said means for generating based upon a signal from said means for identifying.

20. A system, as claimed in claim 19, wherein said computer-readable storage medium further comprises:

means for making at least one adjustment in relation to said plasma monitoring assembly based upon an output from said means for monitoring.