Patent ID: 7211450

Claim:
A method of identifying systematic yield losses, said method comprising: testing produced products using a test sequence, said testing producing yield data, said yield data related to a wafer; dividing said wafer into multiple zones, each said zone containing a number of individual chips, each individual chip being in multiple zones; calculating and storing for each zone of said wafer a first data series R1, wherein each element of said first series is the yield of a said zone of said wafer for each tested wafer of the same size; calculating and storing for each element of R1 a second data series R2, wherein each element of said second series is a p consecutive element moving average of R1; calculating and storing for each element of R1 a third data series R3, wherein each element of said third data series is a p consecutive element moving standard deviation of data series R1; calculating for each element of R1 a trigger point, wherein said trigger point is calculated as the respective R2 element less an adjusted respective R3 value; and triggering a notification when the trigger point calculated for each element of R1 is greater than the respective element of R1, wherein the yield of a zone is the number of acceptable individual chips divided by the total number of chips in said zone.