A method and system of selectively identifying at risk die based on
location within the reticle. Reticle and stepping information is stored
in a database. All reticle shots in a wafer and in a lot are overlaid on
top of each other. The reticle and stepping information is used to
calculate pass/fail or specific bin yield of reticle fields. It is
determined if the yield of some reticle locations is below a statistical
measure by a pre-determined threshold, and if so, all the die in that
location are downgraded. The statistical value to compare against does
not have to be based on the reticle alone. It can be a wafer of lot level
statistic. The process can be applied at a lot or wafer level, or both.