Method and apparatus for monitoring plasma processing operations

• US 6,223,755 B1
• Filed: 04/23/1998
• Issued: 05/01/2001
• 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: Stevenson, Joel O'Don, Ward, Pamela Peardon Denise, Smith, Michael Lane Jr.
• Primary Examiner(s): Markoff, Alexander
• Application Number:
  US09/065,195
• Time in Patent Office: 1,104 Days
• Field of Search: 134/1, 134/1.1, 134/1.2, 134/1.3, 134/18, 134/26, 438/7, 438/8, 438/9, 438/16, 438/905, 422/62, 156/345, 250/578.1, 216/59, 216/60
• US Class Current: 134/1.1
• 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
• CPC Class Codes: Y10S 438/905 Cleaning of reaction chamber

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 preparing a processing chamber for running a plasma recipe on product when loaded in said chamber, said method comprising the steps of:

plasma cleaning an interior of said processing chamber with a plasma, wherein said plasma cleaning step is executed when said processing chamber is empty;

obtaining optical emissions of said plasma within said processing chamber at least a plurality of times during said plasma cleaning step, wherein said obtaining step comprises obtaining an optical emissions segment of said plasma in said processing chamber at each of said plurality of times, wherein each said optical emissions segment comprises optical emissions which includes at least wavelengths from about 250 nanometers to about 1,000 nanometers, inclusive, which defines a first wavelength range, and at a first wavelength resolution throughout said first wavelength range, wherein said first wavelength resolution is defined as a wavelength spacing between each adjacent pair of wavelengths throughout said first wavelength range, and wherein said first wavelength resolution is no more than about 1 nanometer;

comparing a pattern of each of a plurality of said optical emissions segments from said obtaining step with a first standard pattern which is stored on a computer-readable storage medium;

monitoring said comparing step for a first condition, wherein said first condition is when said pattern of at least one of said optical emissions segments from said comparing step matches said first standard pattern and which is equated with an endpoint of said plasma cleaning step; and

terminating said plasma cleaning step if said monitoring step identifies said first condition.

2. A method, as claimed in claim 1, wherein:

said plasma cleaning step comprises removing deposits which have adhered to interior surfaces of said processing chamber during the running of plasma recipes on product within said processing chamber before execution of said plasma cleaning step.

3. A method, as claimed in claim 1, wherein:

said plasma cleaning step comprises removing residuals from interior surfaces of said processing chamber, wherein said residuals exist from a wet clean which was conducted within said interior of said processing chamber before execution of said plasma cleaning step.

4. A method, as claimed in claim 1, wherein:

each of said patterns from said comparing step and said first standard pattern are a plot of intensity versus wavelength at a specific point in time.

5. A method, as claimed in claim 1, wherein:

said first standard pattern was obtained from a previous-in-time plasma cleaning operation conducted in the same said processing chamber.

6. A method, as claimed in claim 1, further comprising the steps of:

opening said processing chamber before said plasma cleaning step;

replacing at least one component within said interior of said processing chamber after said opening step and before said plasma cleaning step; and

sealing said processing chamber after said replacing step, wherein said plasma cleaning step is executed only after execution of said sealing step.

7. A method, as claimed in claim 1, further comprising the steps of:

opening said processing chamber before said plasma cleaning step;

applying at least one type of solvent to at least a portion of interior surfaces of said processing chamber before initiating said plasma cleaning step; and

sealing said processing chamber after said applying step, wherein said plasma cleaning step is executed only after execution of said sealing step.

8. A method, as claimed in claim 1, further comprising the step of:

monitoring an amount of time spent on said plasma cleaning step; and

discontinuing said plasma cleaning step if said monitoring an amount of time step identifies a second condition, wherein said second condition is when said amount of time spent on said plasma cleaning step is at least equal to a predetermined maximum time limit.

9. A method, as claimed in claim 8, further comprising the step of:

initiating a wet clean of said interior of said processing chamber after any execution of said discontinuing step.

10. A method, as claimed in claim 1, wherein:

said first standard pattern is defined by optical emissions of wavelengths within said first wavelength range and at said first wavelength resolution throughout said first wavelength range.

11. A method, as claimed in claim 10, wherein:

said monitoring said comparing step comprises determining a differential between said pattern of each of said plurality of said optical emissions segments from said comparing step and said first standard pattern, wherein said first condition exists when any said differential is free from any substantial peaks.

12. A method, as claimed in claim 10, wherein:

said monitoring said comparing step comprises determining a differential between said pattern of each of said plurality of said optical emissions segments from said comparing step and said first standard pattern, wherein said first condition exists when any said differential is within a predetermined amount of a baseline intensity.

13. A method for preparing a processing chamber for running a plasma recipe on product when loaded in said chamber, said method comprising the steps of:

plasma cleaning an interior of said processing chamber with a plasma, wherein said plasma cleaning step is executed when said processing chamber is empty;

obtaining optical emissions of said plasma within said processing chamber at least a plurality the times during said plasma cleaning step, wherein said obtaining step comprises obtaining an optical emissions segment of said plasma in said processing chamber at each of said plurality of times, wherein each said optical emissions segment comprises optical emissions which includes at least wavelengths from about 250 nanometers to about 1,000 nanometers inclusive, which defines a first wavelength range, and at a first wavelength resolution throughout said first wavelength range, wherein said first wavelength resolution is defined as a wavelength spacing between each adjacent pair of wavelengths throughout said first wavelength range, and wherein said first wavelength resolution is no more than about 1 nanometer;

determining at each of a plurality of times a differential between a pattern of two of said optical emissions segments from different times of said obtaining step;

monitoring said determining step for a first condition, wherein said first condition is when said any said differential from said determining step is at least substantially a flat line without any substantial peaks; and

terminating said plasma cleaning step if said monitoring step identifies said first condition.

14. A method, as claimed in claim 13, wherein:

said plasma cleaning step comprises removing deposits which have adhered to interior surfaces of said processing chamber during the running of plasma recipes on product within said processing chamber before execution of said plasma cleaning step.

15. A method, as claimed in claim 13, wherein:

said plasma cleaning step comprises removing residuals from interior surfaces of said processing chamber, wherein said residuals exist from a wet cleaning operation which was conducted within said interior of said processing chamber before execution of said plasma cleaning step.

16. A method, as claimed in claim 13, wherein:

said determining step comprises determining an amount of said differential between said pattern of each of said plurality of said optical emissions segments from said obtaining step with said pattern of said optical emissions segment from an immediately preceding time of said obtaining step.

17. A method, as claimed in claim 13, wherein:

said determining step defines a time rate of change of said optical emissions within said processing chamber during said plasma cleaning step.

18. A method, as claimed in claim 13, further comprising the step of:

monitoring an amount of time spent on said plasma cleaning step; and

discontinuing said plasma cleaning step if said monitoring an amount of time step identifies a second condition, wherein said second condition is when said amount of time spent on said plasma cleaning step is at least equal to a predetermined maximum time limit.

19. A method, as claimed in claim 13, further comprising the steps of:

opening said processing chamber before said plasma cleaning step;

replacing at least one component within said interior of said processing chamber after said opening step and before said plasma cleaning step; and

sealing said processing chamber after said replacing step, wherein said plasma cleaning step is executed only after execution of said sealing step.

20. A method, as claimed in claim 13, further comprising the steps of:

opening said processing chamber before said plasma cleaning step;

applying at least one type of solvent to at least a portion of interior surfaces of said processing chamber before initiating said plasma cleaning step; and

sealing said processing chamber after said applying step, wherein said plasma cleaning step is executed only after execution of said sealing step.

21. A method, as claimed in claim 13, wherein:

said determining step comprises sequentially determining a differential of said pattern of each said optical emissions segment from said obtaining step with said pattern of said optical emissions segment from an immediately preceding time of said obtaining step.

22. A method, as claimed in claim 13, wherein:

each said pattern is a plot of intensity versus wavelength at a specific point in time.