Method and apparatus for determining a root cause of a statistical process control failure

1. A method, comprising:

detecting at least one fault associated with at least one first wafer processed according to a first processing context, the first processing context comprising a first plurality of processing tools;

processing at least one second wafer according to at least one second processing context, said at least one second processing context comprising at least one second plurality of processing tools, said at least one second plurality of processing tools being different than said at least one first plurality of processing tools; and

determining a root cause associated with said at least one fault based on said at least one first processed wafer and said at least one second processed wafer, the root cause being associated with one of the first plurality of processing tools.

2. The method of claim 1 , wherein detecting said at least one fault associated with said at least one first wafer comprises performing at least one measurement on said at least one first wafer.

3. The method of claim 2 , wherein detecting said at least one fault comprises comparing said at least one measurement to at least one control limit.

4. The method of claim 1 , wherein processing said at least one second wafer according to said at least one second processing context comprises selecting said at least one second wafer for processing according to said at least one second processing context based upon said at least one first processing context such that at least one of the second plurality of processing tools is different than at least one of the first plurality of processing tools.

5. The method of claim 1 , wherein processing said at least one second wafer according to said at least one second processing context comprises selecting said at least one second wafer for processing according to at least one second processing context, the number of processing tools in said at least one second processing context being different from the number of processing tools in said at least one first processing context.

6. The method of claim 1 , wherein processing said at least one second wafer according to said at least one second processing context comprises selecting said at least one second wafer such that at least one of a product design, a thread, a processing tool, and an operating recipe associated with said at least one second processing context differs from at least one corresponding product design, thread, processing tool, and operating recipe associated with said at least one first processing context.

7. The method of claim 1 , wherein processing said at least one second wafer comprises dispatching said at least one second wafer for processing according to said at least one second processing context.

8. The method of claim 7 , wherein dispatching said at least one second wafer comprises dispatching said at least one second wafer according to a determined priority.

9. The method of claim 1 , wherein determining the root cause associated with said at least one fault comprises determining whether a fault is associated with said at least one second processed wafer.

10. The method of claim 9 , wherein determining the root cause comprises performing a commonality analysis based on the at least one fault associated with said at least one first processed wafer and on whether a fault is associated with said at least one second processed wafer.

11. The method of claim 1 , wherein determining the root cause associated with said at least one fault comprises modifying at least one sampling plan.

12. An apparatus, comprising:

at least one processing tool for processing wafers according to a processing context; and

a controller configured to:

detect at least one fault associated with at least one first wafer processed according to a first processing context, the first processing context comprising a first plurality of processing tools;

dispatch at least one second wafer to said at least one processing tool for processing according to at least one second processing context, said at least one second processing context comprising at least one second plurality of processing tools, said at least one second plurality of processing tools being different than said at least one first plurality of processing tools; and

determine a root cause associated with said at least one fault based on said at least one first processed wafer and said at least one second processed wafer, the root cause being associated with one of the first plurality of processing tools.

13. The apparatus of claim 12 , comprising at least one measurement tool for performing at least one measurement on processed wafers, wherein said at least one measurement tool is configured to perform at least one measurement on said at least one first wafer.

14. The apparatus of claim 13 , wherein the controller is configured to detect said at least one fault associated with said at least one first wafer based on said at least one measurement performed on said at least one first wafer.

15. The apparatus of claim 14 , wherein the controller is configured to compare said at least one measurement to at least one control limit.

16. The apparatus of claim 12 , wherein the controller is configured to select said at least one second wafer for processing according to said at least one second processing context based upon said at least one first processing context such that at least one of the second plurality of processing tools is different than at least one of the first plurality of processing tools.

17. The apparatus of claim 12 , wherein the controller is configured to select said at least one second wafer for processing according to at least one second processing context, the number of processing tools in said at least one second processing context being different from the number of processing tools in said at least one first processing context.

18. The apparatus of claim 12 , wherein the controller is configured to select said at least one second wafer such that at least one of a product design, a thread, a processing tool, and an operating recipe associated with said at least one second processing context differs from at least one corresponding product design, thread, processing tool, and operating recipe associated with said at least one first processing context.

19. The apparatus of claim 12 , wherein the controller is configured to dispatch said at least one second wafer according to a determined priority.

20. The apparatus of claim 12 , wherein the controller is configured to determine whether a fault is associated with said at least one second processed wafer.

21. The apparatus of claim 20 , wherein the controller is configured to perform a commonality analysis based on the at least one fault associated with said at least one first processed wafer and on whether a fault is associated with said at least one second processed wafer.

22. The apparatus of claim 12 , wherein the controller is configured to modify at least one sampling plan.

23. An apparatus, comprising:

means for detecting at least one fault associated with at least one first wafer processed according to a first processing context, the first processing context comprising a first plurality of processing tools;

means for processing at least one second wafer according to at least one second processing context, said at least one second processing context comprising at least one second plurality of processing tools said at least one second plurality of processing tools being different than said at least one first plurality of processing tools; and

means for determining a root cause associated with said at least one fault based on said at least one first processed wafer and said at least one second processed wafer, the root cause being associated with one of the first plurality of processing tools.