Method and apparatus for monitoring plasma processing operations

• US 6,123,983 A
• Filed: 04/23/1998
• Issued: 09/26/2000
• 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 O'Don
• Primary Examiner(s): Till, Terrence R.
• Assistant Examiner(s): ALDAG, ANDREW J
• Application Number:
  US09/065,257
• Time in Patent Office: 887 Days
• Field of Search: 118/723 R, 438/9, 702/84, 702/188, 702/31, 702/23, 216/59, 216/60, 156/345, 204/192.33, 204/298.32, 427/8, 427/10, 700/110, 700/121, 356/316
• US Class Current: 427/10
• 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 system for running a plasma process, said system comprising:

a processing chamber;

a plasma generator in said plasma chamber, wherein a plasma process may be run on product in said processing chamber when said plasma generator is activated;

a plasma monitoring assembly operatively interfaced with said processing chamber and comprising a computer-readable storage medium, said computer-readable storage medium comprising a first data structure comprising a plurality of data entries, wherein each said data entry corresponds with a plasma process previously run in said processing chamber, wherein each said data entry is associated with one of first, second, and third categories, wherein each said data entry which has been associated with said first category means that its corresponding said plasma process which was previously run in said processing chamber was at least assumed to have proceeded without substantially any error, wherein each said data entry which has been associated with said first category comprises optical emissions data of at least a portion of a plasma used in its corresponding said plasma process at least every second during at least a first time period of its corresponding said plasma process, said first time period being after said plasma has stabilized and until at least substantially an end of its corresponding said plasma process wherein each said data entry which has been associated with said second category means that its corresponding said plasma process which was previously run in said processing chamber encountered at least one error and further that said at least one error has since been identified in said first data structure of said computer-readable storage medium, wherein each said data entry which has been associated with said second category comprises optical emissions data of at least a portion of a plasma used in its corresponding said plasma process at least at a time of the occurrence of said at least one error and which is indicative of said at least one error, and wherein each said data entry which has been associated with said third category means that its corresponding said plasma process which was previously run in said processing chamber encountered an unknown condition to said plasma monitoring assembly, wherein being a said unknown condition to said plasma monitoring assembly means that at least a portion of said data entry which has been associated with said third category failed to correspond with any said data entry which has been previously associated with either of said first category or said second category, and wherein each said data entry which has been associated with said third category comprises optical emissions data of a plasma used in the corresponding said plasma process at least from a time in the corresponding said plasma process after which the corresponding said plasma process encountered a said unknown condition to said plasma monitoring assembly.

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

said optical emissions data in each said data entry which has been associated with said first category comprises wavelengths from about 250 nanometers to about 1,000 nanometers at least at every 1 nanometer.

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

a first portion of said plurality of data entries is associated with said first category, wherein at least one said data entry of said first portion is from a first plasma recipe previously run on product in said processing chamber, and wherein at least one said data entry of said first portion is from a second plasma recipe previously run on product in said processing chamber, said first plasma recipe being different from said second plasma recipe.

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

a first portion of said plurality of data entries is associated with said first category, wherein at least two said data entries of said first portion are from two separate executions of the same plasma recipe previously run on product in said processing chamber.

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

each said data entry associated with said first category is available for use by said plasma monitoring assembly as a standard to assess future said plasma processes run in said processing chamber.

6. A system, as claimed in claim 1, wherein:

a first portion of said plurality of data entries is associated with said second category, wherein at least one said data entry of said first portion is from a first plasma recipe previously run on product in said processing chamber, and wherein at least one said data entry of said first portion is from a second plasma recipe previously run on product in said processing chamber, said first plasma recipe being different from said second plasma recipe.

7. A system, as claimed in claim 1, wherein:

a first portion of said plurality of data entries is associated with said second category and comprises first and second said data entries, wherein said first and second said data entries are from two separate executions of the same plasma recipe previously run on product in said processing chamber, wherein said first said data entry is indicative of a first error and said second said data entry is indicative of a second error, said first and second errors being different.

8. A system, as claimed in claim 1, wherein:

a first said data entry which has been associated with said third category is from one said plasma process which has been previously run in said processing chamber, during which a first error occurred, and in which said first error has yet to be identified.

9. A system, as claimed in claim 1, wherein:

a first said data entry which is associated with said third category is from one said plasma process which has been previously run on product in said processing chamber and which proceeded without substantially any error but which was not yet contained in said first data structure of said computer-readable medium in association with said first category.

10. A system, as claimed in claim 1, further comprising:

means for transferring at least a portion of any said data entry which is associated with said third category to any one of said first and second categories.

11. A system, as claimed in claim 1, wherein:

said plasma monitoring assembly further comprises means for comparing a current said plasma process against said first data structure of said computer-readable storage medium.

12. A system, as claimed in claim 1, wherein:

said first data structure is available for said plasma processes selected from the group consisting of plasma recipes which are run on at least one product in said processing chamber, plasma cleaning operations, plasma conditioning operations, and qualification wafer operations.

13. A plasma monitoring system for a plasma process run in a processing chamber, said system comprising:

a computer-readable storage medium comprising;

a first data structure comprising a plurality of data entries on a plurality of plasma processes previously run in said processing chamber, wherein each said data entry is associated with one of first, second, and third categories, respectively, wherein each said data entry which has been associated with said first category means that its corresponding said plasma process which was previously run in said processing chamber was at least assumed to have proceeded without substantially any error, wherein each said data entry which has been associated with said first category comprises optical emissions data of at least a portion of a plasma used in its corresponding said plasma process at least every second during at least a first time period of its corresponding said plasma process, said first time period being after said plasma has stabilized and until at least substantially an end of its corresponding said plasma process, wherein each said data entry which has been associated with said second category means that its corresponding said plasma process which was previously run in said processing chamber encountered at least one error and in which said at least one error has since been identified in said first data structure of said computer-readable storage medium, wherein each said data entry which has been associated with said second category comprises optical omissions data of at least a portion of a plasma used in its corresponding said plasma process at least at a time of the occurrence of said at least one error and which is indicative of said at least one error, and wherein each said data entry which has been associated with said third category means that its corresponding said plasma process which was previously run in said processing chamber encountered an unknown condition to said plasma monitoring system, wherein being a said unknown condition to said plasma monitoring system means that at least a portion of said data entry which has been associated with said third category failed to correspond with any said data entry which has been previously associated with either of said first category or said second category, and wherein each said data entry which has been associated with said third category comprises optical omissions data of a plasma used in the corresponding said plasma process at least from a time in the corresponding said plasma process after which the corresponding said plasma process encountered a said unknown condition to said plasma monitoring system; and

means for comparing a current said plasma process against at least one said data entry in said first data structure.

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

said means for comparing comprises means for comparing said current said plasma process against each said data entry associated with said first category before comparing said current said plasma process against any said data entry associated with said second category.

15. A method for initializing a system for running plasma processes, said system comprising a processing chamber and a plasma monitoring assembly which is operatively interfaced with said processing chamber and which comprises a computer-readable storage medium, said computer-readable storage medium comprising a first data structure comprising a plurality of data entries, wherein each said data entry is associated with one of a first category, a second category, or a third category, wherein each said data entry which has been associated with said first category is from one said plasma process which has been previously run in said processing chamber and which is at least assumed to have proceeded without substantially any error, wherein each said data entry which has been associated with said second category is from one said plasma process which has been previously run in said processing chamber where at least one error occurred and in which said at least one error has since been identified in said first data structure of said computer-readable storage medium, wherein each said data entry which has been associated with said third category is from one said plasma process which has been previously run in said processing chamber and which is an unknown condition to said first data structure, wherein being a said unknown condition to said first data structure means that at least a portion of said data entry which has been associated with said third category failed to correspond with any said data entry which has been previously associated with either said first category or said second category, wherein a conducting a plasma process step comprises the steps of generating a plasma in said processing chamber, obtaining optical emissions data of said plasma within said processing chamber, and terminating said generating step, and wherein said method comprises the steps of:

executing a first said conducting step;

executing a first recording step comprising recording a first said data entry in said first data structure of said computer-readable storage medium, said first said data entry comprising said optical emissions data of at least a portion of said plasma from said executing a first said conducting step at least every second during a least a first time period of said executing a first said conducting step, said first time period being after said plasma has stabilized and until at least substantially an end of said executing a first said conducting step;

executing a first assigning step comprising assigning said first said data entry to said first category;

executing a second said conducting step;

executing a first evaluating step comprising determining if said optical emissions data from said executing a second said conducting step corresponds with optical emissions data from at least one said data entry which is assigned to said first category or said second category;

executing a second recording step comprising recording at least a portion of said optical emissions data from said executing a second said conducting step in a second said data entry in said first data structure of said computer-readable storage medium, said optical emissions data associated with said executing a second recording step being at least from a time when said optical emissions data from said executing a second said conducting step failed to correspond with optical emissions data from said at least said one data entry which is assigned to said first category or said second category and is thereby a first said unknown condition;

analyzing at least a portion of said optical emissions data from said executing a second recording step, said analyzing step being executed after said executing a second recording step;

identifying a first error in said executing a second said conducting step, said identifying step using said analyzing step;

retaining at least a portion of said optical emissions data from said executing a second recording step in said second said data entry from a time of an occurrence of said first error and which is indicative of said first error;

executing a second assigning step comprising assigning said second said data entry to said second category after said identifying step;

executing a third said conducting step;

executing a second evaluating step comprising determining if said optical emissions data from said executing a third said conducting step corresponds with optical emissions data from said at least one data entry which is assigned to said first category or said second category;

executing a third recording step comprising recording at least a portion of said optical emissions data from said executing a third said conducting step in a third said data entry in said first data structure of said computer-readable storage medium, said optical emissions data associated with said executing a third recording step being at least from a time when said optical emissions data from said executing a third said conducting step failed to correspond with optical emissions data from said at least one said data entry which is assigned to said first category or said second category and is thereby a second said unknown condition;

executing a third assigning step comprising assigning said third said data entry to said third category.

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

said conducting a plasma process step comprises conducting a plasma process selected from the group consisting of plasma recipes which are run on at least one product in said processing chamber, plasma cleaning operations, plasma conditioning operations, and qualification wafer operations.

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

said optical emissions data associated with said conducting a plasma process step comprise obtaining wavelengths from about 250 nanometers to about 1,000 nanometers and at least at every 1 nanometer.

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

said obtaining step comprises obtaining optical emissions at least every 1 second during at least a substantial portion of said conducting a plasma process step.

19. A method, as claimed in claim 15, further comprising the step of:

confirming that said executing a first said conducting step proceeded without substantially any error after a completion of said executing a first said conducting step.

20. A method, as claimed in claim 15, further comprising the steps of:

analyzing at least a portion of said optical emissions data from said executing a third said conducting step.

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

identifying a second error in said executing a third said conducting step, said identifying a second error step comprises using said analyzing step which is associated with said executing a third said conducting step; and

retaining at least those said optical emissions data from said executing a third said recording step in said third said data entry from a time of an occurrence of said second error and which is indicative of said second error.

22. A method, as claimed in claim 15, further comprising the steps of:

analyzing at least a portion of said optical emissions data from said executing a third recording step, and

reassigning said third said data entry from said third category to said first category after said analyzing step.