Dynamic metrology schemes and sampling schemes for advanced process control in semiconductor processing

• US 7,698,012 B2
• Filed: 05/01/2002
• Issued: 04/13/2010
• Est. Priority Date: 06/19/2001
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Schwarm, Alexander T., Shanmugasundram, Arulkumar P.
• Primary Examiner(s): Jarrett; Ryan A
• Application Number:
  US10/135,451
• Publication Number:
  US 20020193899A1
• Time in Patent Office: 2,904 Days
• Field of Search: 702/83, 700/108, 700/121, 700/109, 700/110
• US Class Current: 700/110
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/03 according to the final size of the previously ground workpiece
• CPC Class Codes: B24B 49/18 taking regard of the presence of dressing tools
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: G05B 19/00 Programme-control systems
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32053 Adjust work parameter as function of other cell
• CPC Class Codes: G05B 2219/32065 Synchronise set points of processes
• CPC Class Codes: G05B 2219/45031 Manufacturing semiconductor wafers
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/67276 Production flow monitoring, e.g. for increasing throughput program-control systems per se G05B19/00, e.g. total factory control G05B19/418
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

Systems, methods and mediums are provided for dynamic adjustment of sampling plans in connection with a wafer (or other device) to be measured. A sampling plan provides information on specific measure points within a die, a die being the section on the wafer that will eventually become a single chip after processing. There are specified points within the die that are candidates for measuring. The stored die map information may be retrieved and translated to determine the available points for measurement on the wafer.

The invention adjusts the frequency and/or spatial resolution of measurements when one or more events occur that are likely to indicate an internal or external change affecting the manufacturing process or results. The increase in measurements and possible corresponding decrease in processing occur on an as-needed basis. The dynamic metrology plan adjusts the spatial resolution of sampling within-wafer by adding, subtracting or replacing candidate points from the sampling plan, in response to certain events which suggest that additional or different measurements of the wafer may be desirable. Where there are provided a number of candidate points in the die map in the area to which points are to be added, subtracted, or replaced, the system can select among the points. Further, the invention may be used in connection with adjusting the frequency of wafer-to-wafer measurements.

Claims

1. A computer-implemented method of measuring at least one manufacturing characteristic for at least one wafer from a lot of wafers processed by a process control system, comprising:

providing information representative of a set of candidate points to be measured by the process control system on the at least one wafer from the lot of wafers;

executing, by the process control system, a plan for the lot of wafers for performing measurements on the at least one wafer to measure the at least one manufacturing characteristic, the plan defining the measurements to be made responsive to the set of candidate points;

detecting, by the process control system, that one of a plurality of events indicating a change in a manufacturing process occurs while processing the lot of wafers, or that a lack of one of the plurality of events occurs while processing the lot of wafers, the plurality of events comprising an occurrence of a fault in a processing device used to process the lot of wafers, and an occurrence of a variation in a measurement of a previously measured wafer from the lot of wafers;

determining, by the process control system while processing the lot of wafers, whether to measure the at least one wafer from the lot of wafers based on the detected event or lack of the event; and

adjusting the plan, by the process control system while processing the lot of wafers, to measure the at least one wafer from the lot of wafers and to refrain from measuring the at least one wafer from the lot of wafers based on the detected event or lack of the event.

2. The method of claim 1, wherein the manufacturing process is an automated semi-conductor manufacturing process.

3. The method of claim 1, wherein the plan further includes information representative of a metrology recipe.

4. The method of claim 1, wherein the candidate points are included in a map corresponding to the at least one wafer.

5. The method of claim 1, wherein the plan is a pre-determined sampling plan.

6. The method of claim 5, wherein at least one of:

the sampling plan comprises a plurality of splines radiating from a center of the at least one wafer, and wherein the candidate points are distributed along the splines.

7. The method of claim 6, wherein a distribution of the candidate points along the splines is weighted according to a surface area of the at least one wafer.

8. The method of claim 5, wherein the sampling plan includes a plurality of radially distributed candidate points.

9. The method of claim 1, wherein the plan defines at least one region on the wafer, each of the candidate points corresponding to the at least one region.

10. The method of claim 1, wherein adjusting the plan comprises:

selecting at least one measurement responsive to the candidate points for the at least one wafer;

assigning the selected at least one measurement as an additional measurement to be performed or as a measurement to be removed under the plan; and

revising at least one of the measurements, the selected measurement, and the plan.

11. The method of claim 1, wherein adjusting the plan comprises:

determining whether the detected event or the lack of the event may affect a series of wafers from the lot of wafers; and

determining whether to measure at least one of the wafers in the series of wafers based on the determination of whether the series of wafers may be affected.

12. The method of claim 11, wherein there is provided a plurality of wafers in a group, including the at least one wafer, and wherein the plan further comprises:

first information representative of the wafers in the group that are available to be measured; and

second information representative of the wafers in the group that are to be measured under the plan.

13. The method of claim 1, further comprising discarding information representative of measurement results on the at least one wafer when at least one of:

the measurement results indicate a variation in measurement of the at least one wafer, and a fault is detected in the processing device used to process the lot of wafers.

14. The method of claim 1, wherein the plan comprises:

a plurality of splines radiating from a center of the at least one wafer, the candidate points being distributed along the splines; and

a distribution of the candidate points along the splines weighted according to a surface area of the at least one wafer.

15. A computer-implemented system of measuring at least one manufacturing characteristic for at least one wafer from a lot of wafers processed by a process control system, comprising:

a memory to store information representative of a set of candidate points to be measured by the process control system on the at least one wafer from the lot of wafers, and information representative of a plan for the lot of wafers for performing measurements on the at least one wafer to measure the at least one manufacturing characteristic, the plan defining the measurements to be made responsive to the set of candidate points; and

a processor, coupled to the memory, to

detect that one of a plurality of events indicating a change in a manufacturing process occurs while processing the lot of wafers, or that a lack of one of the plurality of events occurs while processing the lot of wafers, the plurality of events comprising an occurrence of a fault in a processing device used to process the lot of wafers, and an occurrence of a variation in a measurement of a previously measured wafer from the lot of wafers;

determine, while processing the lot of wafers, whether to measure the at least one wafer from the lot of wafers based on the detected event or lack of the event; and

adjust the plan, while processing the lot of wafers, to measure the at least one wafer from the lot of wafers and to refrain from measuring the at least one wafer from the lot of wafers based on the detected event or lack of the event.

16. The system of claim 15, wherein the manufacturing process is an automated semi-conductor manufacturing process, further comprising at least one metrology tool for performing measurements on the wafer, operatively connected to the processor.

17. The system of claim 15, wherein the plan further includes information representative of a metrology recipe.

18. The system of claim 15, wherein the candidate points are included in a map corresponding to the at least one wafer.

19. The system of claim 15, wherein the plan is a pre-determined sampling plan.

20. The system of claim 19, wherein at least one of:

the sampling plan includes a plurality of splines radiating from a center of the at least one wafer, and wherein the candidate points are distributed along the splines.

21. The system of claim 20, wherein a distribution of the candidate points along the splines is weighted according to a surface area of the at least one wafer.

22. The system of claim 15, wherein the sampling plan includes a plurality of radially distributed candidate points.

23. The system of claim 15, wherein the plan defines at least one region on the wafer, each of the candidate points corresponding to the at least one region.

24. The system of claim 15, wherein to adjust the plan comprises:

selecting at least one measurement responsive to the candidate points for the at least one wafer;

assigning the selected at least one measurement as an additional measurement to be performed or as a measurement to be removed under the plan; and

revising at least one of the measurements, the selected measurement, and the plan.

25. The system of claim 15, wherein to adjust the plan comprises:

determining whether the detected event or the lack of the event may affect a series of wafers from the lot of wafers; and

determining whether to measure at least one of the wafers in the series of wafers based on the determination of whether the series of wafers may be affected.

26. The system of claim 25, wherein there is provided a plurality of wafers in a group, including the at least one wafer, and wherein the plan further comprises:

first information representative of the wafers in the group that are available to be measured; and

second information representative of the wafers in the group that are to be measured under the plan.

27. The system of claim 15, wherein the memory is further to store information representative of measurement results on the at least one wafer, except when at least one of:

the measurement results indicate a variation in measurement of the at least one wafer, and when a fault is detected in the processing device used to process the lot of wafers.

28. The system of claim 15, wherein the plan comprises:

a plurality of splines radiating from a center of the at least one wafer, the candidate points being distributed along the splines; and

a distribution of the candidate points along the splines weighted according to a surface area of the at least one wafer.

29. A computer readable medium for measuring at least one manufacturing characteristic for at least one wafer from a lot of wafers processed by a process control system, comprising executable instructions which when executed on a processing system cause the processing system to perform a method comprising:

providing information representative of a set of candidate points to be measured by the process control system on the at least one wafer from the lot of wafers;

executing, by the process control system, a plan for the lot of wafers for performing measurements on the at least one wafer to measure the at least one manufacturing characteristic, the plan defining the measurements to be made responsive to the set of candidate points;

detecting, by the process control system, that one of a plurality of events indicating a change in a manufacturing process occurs while processing the lot of wafers, or that a lack of one of the plurality of events occurs while processing the lot of wafers, the plurality of events comprising an occurrence of a fault in a processing device used to process the lot of wafers, and an occurrence of a variation in a measurement of a previously measured wafer from the lot of wafers

determining, by the process control system while processing the lot of wafers, whether to measure the at least one wafer from the lot of wafers based on the detected event or lack of the event; and

adjusting the plan, by the process control system while processing the lot of wafers, to measure the at least one wafer from the lot of wafers and to refrain from measuring the at least one wafer from the lot of wafers based on the detected event or lack of the event.

30. The computer readable medium of claim 29, wherein the manufacturing process is an automated semi-conductor manufacturing process.

31. The computer readable medium of claim 29, wherein the plan further includes information representative of a metrology recipe.

32. The computer readable medium of claim 29, wherein the candidate points are included in a map corresponding to the at least one wafer.

33. The computer readable medium of claim 29, wherein the plan is a pre-determined sampling plan.

34. The computer readable medium of claim 33, wherein at least one of:

the sampling plan includes a plurality of splines radiating from a center of the at least one wafer, and wherein the candidate points are distributed along the splines.

35. The computer readable medium of claim 34, wherein a distribution of the candidate points along the splines is weighted according to a surface area of the at least one wafer.

36. The computer readable medium of claim 33, wherein the sampling plan includes a plurality of radially distributed candidate points.

37. The computer readable medium of claim 29, wherein the plan defines at least one region on the wafer, each of the candidate points corresponding to the at least one region.

38. The computer readable medium of claim 29, wherein adjusting the plan comprises:

selecting at least one measurement responsive to the candidate points for the at least one wafer;

assigning the selected at least one measurement as an additional measurement to be performed or as a measurement to be removed under the plan; and

revising at least one of the measurements, the selected measurement, and the plan.

39. The computer readable medium of claim 29, wherein adjusting the plan comprises:

determining whether the detected event or the lack of the event may affect a series of wafers; and

determining whether to measure at least one of the wafers in the series of wafers based on the determination of whether the series of wafers may be affected.

40. The computer readable medium of claim 39 wherein there is provided a plurality of wafers in a group, including the at least one wafer, and wherein the plan further comprises:

first information representative of the wafers in the group that are available to be measured; and

second information representative of the wafers in the group that are to be measured under the plan.

41. The computer readable medium of claim 29, further comprising instructions for discarding information representative of measurement results on the at least one wafer when at least one of:

the measurement results indicate a variation in measurement of the at least one wafer, and when a fault is detected in the processing device used to process the lot of wafers.

42. The computer readable medium of claim 29, wherein the plan comprises:

a plurality of splines radiating from a center of the at least one wafer, the candidate points being distributed along the splines; and

a distribution of the candidate points along the splines weighted according to a surface area of the at least one wafer.

43. A computer-implemented system of measuring at least one manufacturing characteristic for at least one wafer from a lot of wafers processed by a process control system, comprising:

means for representing a set of candidate points to be measured by the process control system on the at least one wafer from the lot of wafers;

means for providing a plan for the lot of wafers for performing measurements on the at least one wafer to measure the at least one manufacturing characteristic, the plan defining the measurements to be made responsive to the set of candidate points;

means for detecting that one of a plurality of events indicating a change in a manufacturing process occurs while processing the lot of wafers, or that a lack of one of the plurality of events occurs while processing the lot of wafers, the plurality of events comprising an occurrence of a fault a processing device used to process the lot of wafers, and an occurrence of a variation in a measurement of a previously measured wafer from the lot of wafers;

means for determining, while processing the lot of wafers, whether to measure the at least one wafer from the lot of wafers based on the detected event or lack of the event; and

means for adjusting the plan, while processing the lot of wafers, to measure the at least one wafer from the lot of wafers and to refrain from measuring the at least one wafer from the lot of wafers based on the detected event or lack of the event.

44. The system of claim 43, wherein the manufacturing process is an automated semi-conductor manufacturing process, further comprising at least means for performing measurements on the wafer.

45. The system of claim 43, wherein the plan further includes information representative of a metrology recipe.

46. The system of claim 43, wherein the candidate points are included in a map corresponding to the at least one wafer.

47. The system of claim 43, wherein the plan is a pre-determined sampling plan.

48. The system of claim 47, wherein at least one of:

the sampling plan includes a plurality of splines radiating from a center of the at least one wafer, and wherein the candidate points are distributed along the splines.

49. The system of claim 48, wherein a distribution of the candidate points along the splines is weighted according to a surface area of the at least one wafer.

50. The system of claim 43, wherein the sampling plan includes a plurality of radially distributed candidate points.

51. The system of claim 43, wherein the plan defines at least one region on the wafer, each of the candidate points corresponding to the at least one region.

52. The system of claim 43, wherein the means for adjusting the plan comprises:

selecting at least one measurement responsive to the candidate points for the at least one wafer;

assigning the selected at least one measurement as an additional measurement to be performed or as a measurement to be removed under the plan; and

revising at least one of the measurements, the selected measurement, and the plan.

53. The system of claim 43, wherein the means for adjusting the plan comprises:

determining whether the detected event or the lack of the event may affect a series of wafers; and

determining whether to measure at least one of the wafers in the series of wafers based on the determination of whether the series of wafers may be affected.

54. The system of claim 53, wherein there is provided a plurality of wafers in a group, including the at least one wafer, and wherein the plan further comprises:

first information representative of the wafers in the group that are available to be measured; and

second information representative of the wafers in the group that are to be measured under the plan.

55. The system of claim 43, further comprising means for representing measurement results on the at least one wafer, except when at least one of:

the measurements results indicate a variation in measurement of the at least one wafer, and when a fault is detected in the processing device used to process the lot of wafers.

56. The system of claim 43, wherein the plan comprises:

a plurality of splines radiating from a center of the at least one wafer, the candidate points being distributed along the splines; and

a distribution of the candidate points along the splines weighted according to a surface area of the at least one wafer.