Automatic maverick wafer screening using die pass pattern

1 . A method for automatically performing maverick screening of a semiconductor wafer, the method comprising:

acquiring an inspection pass status for each of a plurality of die on a subject wafer, the inspection pass status being whether the corresponding die passed or failed inspection;

for each of multiple zones of the subject wafer, comparing a pass/fail percentage of the die within the corresponding zone with an expected pass/fail percentage for the corresponding zone, the expected pass/fail percentage being dependent on a history of pass/fail percentages for previous dies in a same corresponding zone for previously screened wafers, the comparison resulting in a deviation between the measured pass/fail percentage of the corresponding zone and the expected pass/fail percentage of the corresponding zone; and

identifying the subject wafer as a maverick wafer if the deviation for a predetermined number or more of the multiple zones falls outside of a corresponding deviation tolerance for the respective zone.

2 . The method in accordance with claim 1 , the multiple zones being multiple concentric zones.

3 . The method in accordance with claim 2 , the predetermined number being one, such that the subject wafer is identified as a maverick wafer if the deviation for any of the multiple concentric zones falls outside of a corresponding deviation tolerance for the respective concentric zone.

4 . The method in accordance with claim 2 , the previously screened wafers being a predetermined number of most recently screened wafers.

5 . The method in accordance with claim 2 , the expected pass/fail percentage for each concentric zone being a median of the pass/fail percentages at the same corresponding concentric zone for the previously screened wafers.

6 . The method in accordance with claim 2 , the deviation tolerance for each of the multiple concentric zones also being depended on a history of pass/fail percentages for previous dies in a same corresponding concentric zone for the previously screened wafers.

7 . The method in accordance with claim 6 , the deviation tolerance for each of the multiple concentric zones being proportional to a standard deviation of the pass/fail percentages for previous dies in a same corresponding concentric zone for the previously screened wafers.

8 . The method in accordance with claim 2 , the plurality of die on the subject wafer being less than all of the die on the subject wafer.

9 . The method in accordance with claim 2 , the plurality of die on the subject wafer being die that are outside of an exclusion zone at a periphery of the subject wafer.

10 . The method in accordance with claim 9 , the plurality of die on the subject wafer being less than all of the die that are outside of the exclusion zone of the subject wafer.

11 . The method in accordance with claim 2 , the multiple concentric zones comprising three or more concentric zones.

12 . The method in accordance with claim 2 , the multiple concentric zones comprising five or more concentric zones.

13 . The method in accordance with claim 2 , the subject wafer being a first subject wafer, the history being a first history, the method further comprising:

acquiring an inspection pass status for each of a plurality of die on a second subject wafer;

for each of the multiple concentric zones of the second subject wafer, comparing a pass/fail percentage of the die within the corresponding concentric zone with an expected pass/fail percentage for the corresponding concentric zone of the second subject wafer, the expected pass/fail percentage for the corresponding concentric zone of the second subject wafer being dependent on a second history of pass/fail percentages for previous dies in a same corresponding concentric zone for previously screened wafers in the second history, the comparison resulting in a deviation between the measured pass/fail percentage of the corresponding concentric zone of the second subject wafer and the expected pass/fail percentage of the corresponding concentric zone based on the second history; and

identifying the second subject wafer as a maverick wafer if the deviation for the predetermined number or more of the multiple concentric zones of the second subject wafer falls outside of a corresponding deviation tolerance for the respective concentric zone.

14 . The method in accordance with claim 2 , further comprising:

updating the history to thereby update the expected pass/fail percentage and deviation tolerance for each of the multiple concentric zones for the next subject wafer to be screened.

15 . The method in accordance with claim 14 , the subject wafer being a first subject wafer, the method further comprising:

acquiring an inspection pass status for each of a plurality of die on a second subject wafer;

for each of the multiple concentric zones of the second subject wafer, comparing a pass/fail percentage of the die within the corresponding concentric zone with the updated expected pass/fail percentage for the corresponding concentric zone of the second subject wafer, resulting in a deviation between the measured pass/fail percentage of the corresponding concentric zone of the second and the expected pass/fail percentage of the corresponding concentric zone based on the updated pass history; and

identifying the second subject wafer as a maverick wafer if the deviation for the predetermined number or more of the multiple concentric zones of the second subject wafer falls outside of a corresponding updated deviation tolerance for the respective concentric zone.

16 . The method in accordance with claim 15 , the acquiring of the inspection status comprising performing wafer-level testing of the plurality of die on the subject wafer, the wafer-level testing resulting in the inspection pass status for each of the plurality of die on the subject wafer.

17 . A computer program product comprising one or more computer-readable media having thereon computer-executable instructions that, when executed by one or more processors of a computing system, configure the computing system to automatically performing maverick screening of semiconductor wafers by performing operations comprising:

acquiring an inspection pass status for each of a plurality of die on a subject wafer, the inspection pass status being whether the corresponding die passed or failed inspection;

for each of multiple zones of the subject wafer, comparing a pass/fail percentage of the die within the corresponding zone with an expected pass/fail percentage for the corresponding zone, the expected pass/fail percentage being dependent on a history of pass/fail percentages for previous dies in a same corresponding zone for previously screened wafers, the comparison resulting in a deviation between the measured pass/fail percentage of the corresponding zone and the expected pass/fail percentage of the corresponding zone; and

identifying the subject wafer as a maverick wafer if the deviation for a predetermined number or more of the multiple zones falls outside of a corresponding deviation tolerance for the respective zone.

18 . The computer program product in accordance with claim 17 , the multiple zones being multiple concentric zones.

19 . The computer program product in accordance with claim 17 , the acquiring of the inspection status comprising performing wafer-level testing of the plurality of die on the subject wafer, the wafer-level testing resulting in the inspection pass status for each of the plurality of die on the subject wafer.

20 . A computing system comprising:

one or more processors:

one or more computer-readable media having thereon computer-executable instructions that, when executed by one or more processors of a computing system, configure the computing system to automatically performing maverick screening of semiconductor wafers by performing operations comprising:

acquiring an inspection pass status for each of a plurality of die on a subject wafer, the inspection pass status being whether the corresponding die passed or failed inspection;

for each of multiple zones of the subject wafer, comparing a pass/fail percentage of the die within the corresponding zone with an expected pass/fail percentage for the corresponding zone, the expected pass/fail percentage being dependent on a history of pass/fail percentages for previous dies in a same corresponding zone for previously screened wafers, the comparison resulting in a deviation between the measured pass/fail percentage of the corresponding zone and the expected pass/fail percentage of the corresponding zone; and

identifying the subject wafer as a maverick wafer if the deviation for a predetermined number or more of the multiple zones falls outside of a corresponding deviation tolerance for the respective zone.