Method and apparatus for monitoring plasma processing operations

• US 6,261,470 B1
• Filed: 04/23/1998
• Issued: 07/17/2001
• 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): Warden, Sr., Robert J.
• Assistant Examiner(s): Olsen, Kaj K.
• Application Number:
  US09/065,307
• Time in Patent Office: 1,181 Days
• Field of Search: 156/345, 156/345.P, 204/298.32, 702/84, 702/188, 118/723.R, 216/59, 216/60, 364/468.28, 438/9
• US Class Current: 216/60
• 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 currently being run in a processing chamber using a plasma monitoring assembly 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 is on a plasma process previously run in said processing chamber, wherein a first said data entry is on a first said plasma process previously run in said processing chamber and is associated with a first category and wherein a second said data entry is on a second said plasma process previously run in said processing chamber and is associated with a second category, wherein each said data entry associated with said first category contains a plurality of first data segments from a plurality of different times from one said plasma process previously run in said processing chamber, wherein each said data entry associated with said first category defines a standard, wherein each said data entry associated with said second category comprises at least one second data segment from at least one time from one said plasma process previously run in said processing chamber at a time when an error occurred, said at least one second data segment being indicative of said error and identified within said data entry storing said at least one second data segment, and wherein each of said first and second data segments comprise stored optical emissions data, wherein said first data structure further comprises a third category, wherein each said data entry which is associated with said third category comprises at least one third data segment from one said plasma process previously run in said processing chamber which failed to correspond with any said data entry which was at that time associated with said first category and further which failed to correspond with any said data entry which was at that time associated with said second category, said method comprising the steps of:

running a current said plasma process within said processing chamber;

obtaining optical emissions data of said current plasma process during said running step;

performing a first determining step comprising determining if said current said plasma process corresponds with any said plasma process previously run in said processing chamber and stored as a said data entry in association with said first category in said first data structure of said computer-readable storage medium, wherein said performing a first determining step comprises comparing said optical emissions from said obtaining step with at least one said first data segment of at least one said data entry which is associated with said first category;

performing a second determining step comprising determining if said current said plasma process corresponds with any said plasma process previously run in said processing chamber and stored as a said data entry in association with said second category in said first data structure of said computer-readable storage medium, said performing a second determining step being executed only upon occurrence of a first condition, said first condition being if said current said plasma process fails to correspond with any said plasma process previously run in said processing chamber and stored as a said data entry in association with said first category during execution of said performing a first determining step, wherein said performing a second determining step comprises comparing said optical emissions from said obtaining step with at least one said second data segment of at least one said data entry which is associated with said second category; and

recording said optical emissions data from said obtaining step of said running a current said plasma process step if said current said plasma process fails to correspond with at least one said data entry which is associated with said first category and further fails to correspond with at least one said data entry which is associated with said second category, said recording step being to said first data structure and defining one said data entry, said method further comprising the step of associating data entry from said recording step with said third category.

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

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

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

said first data structure comprises a plurality of said data entries which are associated with said first category, wherein a first said data entry which is associated with said first category is from a first said plasma recipe and wherein a second said data entry which is associated with said first category is from a second said plasma recipe, wherein said first said plasma recipe and said second said plasma recipe are different.

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

said first data structure comprises a plurality of said data entries which are associated with said first category, wherein a first said data entry which is associated with said first category is from a first said plasma recipe and wherein a second said data entry which is associated with said first category is also from the same said first plasma recipe.

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

said performing a first determining step comprises determining if said optical emissions data from said obtaining step is within a predetermined tolerance of at least one of said first data segments from at least one of said data entries which is associated with said first category.

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

said performing a first determining step comprises determining if a pattern of said optical emissions data from said obtaining step is at least substantially a match with a pattern of at least one of said first data segments from at least one of said data entries which is associated with said first category.

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

said performing a first determining step comprises determining if said optical emissions data from said obtaining step at a certain point in time in said current said plasma process is within a predetermined tolerance of at least one of said first data segments from at least one of said data entries which is associated with said first category and further which is associated with the same said certain point in time of its corresponding said plasma process previously run in said processing chamber.

8. A method, as claimed in claim 1, wherein in relation to each said data entry which is associated with said first category, said performing a first determining step comprises:

performing a third determining step comprising determining if said optical emissions data from said obtaining step at a current time satisfy a second condition, said second condition being that said optical emissions data from said obtaining step at said current time are within a predetermined tolerance of said stored optical emissions data of at least one of said first data segments from a current said data entry;

designating an earliest-in-time of said at least one of said first data segments of said current said data entry as a current said first data segment if said performing a third determining step identifies said second condition;

terminating said performing a first determining step in relation to said current said data entry if said performing a third determining step fails to identify said second condition;

repeating a loop for said current said data entry if said performing a third determining step identifies said second condition and until execution of an exiting step associated with said loop, said loop comprising the steps of;

increasing said current time by a first increment;

performing a fourth determining step comprising determining if said optical emissions data from said obtaining step at said current time satisfy a third condition, said third condition being that said optical emissions data from said obtaining step at said current time are within a predetermined tolerance of said stored optical emissions data of a next-in-time said first data segment of said current said data entry following said current said first data segment of said current said data entry;

performing a fifth determining step only if said performing a fourth determining step fails to identify said third condition, said performing a fifth determining step comprising determining if said optical emissions data from said obtaining step at said current time satisfy a fourth condition, said fourth condition being that said optical emissions data from said obtaining step at said current time are within a predetermined tolerance of said stored optical emissions data of said current said first data segment of said current said data entry;

exiting said loop when at least one of fifth and sixth conditions exist, said fifth condition being if said performing a fifth determining step was executed and failed to identify said fourth condition, said sixth condition being if all of said optical emissions data from said obtaining step have been evaluated by said performing a first determining step;

setting said next-in-time said first data segment of said current said data entry equal to said current said first data segment only if said performing a fourth determining step identified said third condition.

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

said performing a second determining step comprises determining if a second condition exists, said second condition being that said optical emissions data from said obtaining step is within a predetermined tolerance of at least one of said second data segments from at least one of said data entries which is associated with said second category.

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

initiating a first action if said second condition exists, said first action being selected from the group consisting of terminating said running a current said plasma process step, issuing an alert relating to an existence of said second condition, suspending execution of any additional running of any said plasma processes in said processing chamber for at least a certain amount of time, initiating adjustment of at least one process control parameter having an effect on plasma within said processing chamber from said running a current said plasma process step based upon an existence of said second condition, and any combination of the foregoing.

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

said performing a second determining step comprises determining if a pattern of said optical emissions data from said obtaining step is at least substantially a match with a pattern of at least one of said second data segments from at least one of said data entries which is associated with said second category.

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

said performing a second determining step comprises determining if said optical emissions data from said obtaining step at a certain point in time in said current said plasma process is within a predetermined tolerance of at least one of said second data segments from at least one of said data entries which is associated with said second category and further which is also associated with the same said certain point in time of its corresponding said plasma process previously run in said processing chamber.

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

analyzing said optical emissions data from said recording step after a completion of said running a current said plasma process step; and

transferring at least a portion of said optical emissions data from said recording step from said third category to said second category, said transferring step being executed after a completion of said analyzing step.

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

said analyzing step comprises identifying a first error which occurred during said running a current said plasma process step, and wherein said at least a portion of said optical emissions data associated with said transferring step is indicative of said first error.

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

said at least a portion of said optical emissions data from said transferring step is from less than an entirety of said running a current said plasma process step.

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

said at least a portion of said optical emissions data from said transferring step is from a single point in time of said running a current said plasma process step.

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

analyzing said optical emissions data from said recording step after a completion of said running a current said plasma process step; and

transferring at least a portion of said optical emissions data from said recording step from said third category to said first category, said transferring step being executed after a completion of said analyzing step.

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

said at least a portion of said optical emissions data associated with said transferring step is from a plurality of times during said running a current said plasma process step and is representative of an entirety of said running a current said plasma process step after said plasma in said processing chamber has stabilized.