Method and apparatus for monitoring plasma processing operations

• US 6,269,278 B1
• Filed: 04/23/1998
• Issued: 07/31/2001
• 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): Grant, William
• Assistant Examiner(s): Bahta, Kidest
• Application Number:
  US09/064,970
• Time in Patent Office: 1,195 Days
• Field of Search: 700/121, 700/3, 700/4, 700/17, 700/2, 700/95, 700/96, 414/393, 414/217, 156/345, 156/345.P, 702/84, 702/188, 204/298.32, 210/59, 210/60, 438/9
• US Class Current: 700/121
• 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 first plasma process being run on a first product in a processing chamber, said method comprising the steps of:

loading said first product into said processing chamber;

sealing said processing chamber;

running a first said plasma process on said first product after said sealing step;

obtaining data on plasma used by said running step; and

determining if said processing chamber is in a first condition during said running step, said first condition being that an interior of said processing chamber has been adversely affected by previous said plasma processes run in said processing chamber to the point where it is impacting a performance of said processing chamber to an undesired degree, said determining step using said obtaining data step.

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

said loading step comprises loading at least one wafer into said processing chamber.

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

said running a first said plasma process step comprises running a first plasma recipe, said first plasma recipe comprising a plurality of separate plasma steps, wherein at least two of said plasma steps are different from each other.

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

said obtaining step comprises obtaining optical emissions of plasma in said processing chamber from said running step.

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

monitoring a condition of said plasma in said processing chamber during said running step, wherein said condition is a cumulative result of all parameters having an effect on said plasma in said processing chamber.

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

said obtaining step uses a plasma monitoring assembly which comprises a computer-readable storage medium, said computer-readable storage medium comprising at least one data entry, wherein a first said data entry comprises at least one first data segment.

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

said determining step comprises comparing an output of said obtaining step with said at least one first data segment.

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

said determining step comprises determining when an output of said obtaining step is within a predetermined tolerance of said first data segment and identifying this as said first condition.

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

said determining step comprises determining when a pattern of an output of said obtaining step is at least substantially a match with a pattern of said first data segment and identifying this as said first condition.

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

said obtaining step comprises obtaining current optical emissions of plasma in said processing chamber during said running step, wherein said first data segment comprises stored optical emissions of plasma in said processing chamber during a said plasma process previously run on product in said processing chamber and which was determined, before initiation of said running step, to be representative of said processing chamber when in said first condition, wherein both said current and stored optical emissions include at least wavelengths from about 250 nanometers to about 1,000 nanometers at least at every 1 nanometer, and wherein said determining step comprises determining when a pattern of said current optical emissions at least substantially matches a pattern of said stored optical emissions and identifying this as said first condition.

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

said determining step comprises monitoring a length of time spent on said running step, wherein said determining step comprises determining when said running step takes longer than a first time and equating this with said first condition.

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

said monitoring a length of time step uses an output of said obtaining step.

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

said first said plasma process comprises a plurality of separate plasma steps, wherein said length of time comprises a total amount of time required to complete each said plasma step of said first said plasma process.

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

said first said plasma process comprises first and second plasma steps which are different from each other, said method further comprising the step of monitoring a length of time spent on said first plasma step, wherein said determining step comprises determining when said length of time spent on said first plasma step takes longer than a first time and equating this with said first condition.

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

said monitoring a length of time step uses an output of said obtaining step.

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

said monitoring a length of time step comprises identifying a first endpoint of said first plasma step, wherein said first endpoint is when said first plasma step has produced a first predetermined result on said first product.

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

said first said plasma process comprises a plurality of separate plasma steps, wherein said method further comprises the step of monitoring a length of time spent on each of said plurality of plasma steps, and wherein said determining step comprises determining when any of said plasma steps takes longer than a predetermined time limit associated with said plasma step and equating this with said first condition.

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

said monitoring a length of time step comprises identifying an endpoint of each of said plurality of plasma steps, wherein said endpoint associated with said plasma step is when said plasma step has produced a predetermined result on said first product.

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

notifying personnel of an existence of said first condition when identified by said determining step.

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

initiating a first action if said first condition is identified by said determining step, said first action being selected from the group consisting of terminating said running step, issuing an alert relating to an existence of said first condition, suspending execution of any additional loading steps, and any combination of the foregoing.

21. A plasma monitoring system for a plasma process being run on product in a processing chamber, said system comprising:

a computer readable data storage medium comprising;

means for storing data on a first said plasma process previously run on product in said processing chamber;

means for comparing data on a second said plasma process currently being run on product in said processing chamber with said data in said means for storing; and

first means for determining if said processing chamber is in a first condition, said first condition being that an interior of said processing chamber has been adversely affected by previous said plasma processes run on product in said processing chamber to the point where it is impacting a performance of said processing chamber to an undesired degree, said first means for determining comprising said means for comparing.

22. A system, as claimed in claim 21, wherein:

said means for storing comprises means for storing data representative of optical emissions of plasma in said processing chamber during said first said plasma process.

23. A system, as claimed in claim 21, wherein:

said means for comparing comprises means for evaluating a condition of plasma used by said second said plasma process, wherein said condition of said plasma is a cumulative result of all parameters having an effect on said plasma in said processing chamber during said second said plasma process.

24. A system, as claimed in claim 23, wherein:

said first means for determining comprises said means for evaluating a condition.

25. A system, as claimed in claim 21, wherein:

said first means for determining comprises means for determining when said data provided to said means for comparing from said second said plasma process is within a predetermined tolerance of at least a portion of said data within said means for storing which said first means for determining equates with said first condition.

26. A system, as claimed in claim 21, wherein:

said first means for determining comprises means for determining when a pattern of said data provided to said means for comparing from said second said plasma process is at least substantially a match with a pattern of at least a portion of said data within said means for storing which said first means for determining equates with said first condition.

27. A system, as claimed in claim 21, wherein:

said means for comparing comprises means for comparing data representative of current optical emissions of plasma in said processing chamber during said second said plasma process with at least a portion of said data in said means for storing which comprises stored optical emissions of plasma in said processing chamber from said first said plasma process which was determined, before initiation of said second said plasma process, to be representative of said processing chamber when in said first condition, wherein both said current and stored optical emissions each include at least wavelengths from about 250 nanometers to about 1,000 nanometers at least at every 1 nanometer, and wherein said first means for determining comprises means for determining when a pattern of said current optical emissions at least substantially matches a pattern of said stored optical emissions which said first means for determining equates with said first condition.

28. A system, as claimed in claim 21, further comprising:

means for monitoring a length of time spent on said second said plasma process, said means for monitoring being operatively interfaced with said first means for determining, wherein said first means for determining comprises means for determining when said time spent on said second said plasma process, through said means for monitoring, exceeds a first time which said first means for determining equates with said first condition.

29. A system, as claimed in claim 28, wherein:

said means for monitoring comprises said means for comparing.

30. A system, as claimed in claim 28, wherein:

said second said plasma process comprises a plurality of separate plasma steps, wherein said means for monitoring comprises means for monitoring an amount of time required to complete all of said plasma steps of said second said plasma process.

31. A system, as claimed in claim 21, wherein:

said second said plasma process comprises first and second plasma steps which are different from each other, wherein said system further comprises means for monitoring a length of time spent on said first plasma step, said means for monitoring being operatively interfaced with said first means for determining, wherein said first means for determining comprises means for determining when said time spent on said first plasma step, through said means for monitoring, takes longer than a first time which said first means for determining equates with said first condition.

32. A system, as claimed in claim 31, wherein said means for monitoring comprises said means for comparing.

33. A system, as claimed in claim 31, wherein:

said means for monitoring comprises means for identifying a first endpoint of said first plasma step, wherein said first endpoint is when said first plasma step has produced a first result on said first product.

34. A system, as claimed in claim 21, wherein:

said second said plasma process comprises a plurality of separate plasma steps, wherein said system further comprises means for monitoring a length of time spent on each of said plurality of plasma steps, said means for monitoring being operatively interfaced with said first means for determining, wherein said first means for determining step comprises means for determining when any of said plasma steps takes longer than a predetermined time limit associated with said plasma step which said first means for determining equates with said first condition.

35. A system, as claimed in claim 34, wherein:

said means for monitoring comprises means for identifying an endpoint of each of said plurality of plasma steps, wherein said endpoint associated with said plasma step is when said plasma step has produced a predetermined result on said first product.

36. A system for running a plasma process on product, said system comprising:

a processing chamber comprising a product access and a window, wherein product may be transferred between an interior and exterior of said processing chamber through said product access;

a first gas inlet and a first gas outlet fluidly interconnected with said processing chamber;

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

a plasma monitoring assembly comprising a computer-readable medium, said computer readable medium comprising;

means for storing data on a first said plasma process run on product in said processing chamber previous to said current said plasma process;

means for comparing data on said current said plasma process currently being run on product in said processing chamber with said data on said first said plasma process in said means for storing; and

first means for determining when said processing chamber is in a first condition, said first condition being that an interior of said processing chamber has been adversely affected by previous said plasma processes run on product in said processing chamber to the point where it is impacting a performance of said processing chamber to an undesired degree, said first means for determining comprising said means for comparing.