Every silicon wafer manufactured which will end up as semiconductor devices will be tested 2 or 3 times (as well as many in-line measurements). In order to understand and therefore control the yield of the manufacturing process it is critical to be able to correlate between these different test stages.
The first step towards correlation is to enhance the test data with data from the MES (manufacturing execution system) such as SAP, Oracle, PROMIS or Camstar. The information from these systems gives links between different Lot IDs allowing automated correlation between the stages.
With the data linked between the stages yieldHUB software can correlate wafer by wafer to prove the root cause of your yield variation. Correlation can be carried out between Foundry WAT data and probe test, WAT and final test or final test and probe.
Only cross stage or genealogy correlation can prove the relation between foundry WAT parameters and parametric performance of your product. Our Fabless customers and IDM customers both utilise this function.