Concurrent process model and specification cause-effect monitoring using alternate diagnostic signatures

With technology scaling, the impact of intra and inter-die process variations on the performance of mixed-signal/RF circuits has increased, making process monitoring a critical task in the overall silicon manufacturing flow. We propose a novel process-specification cause-effect monitoring scheme that allows the effects of process variations and shifts on device specifications to be monitored on a per-IC basis as opposed to existing techniques that rely only on electrical test data gathered across lots of wafers. The method relies on the use of alternate diagnostic tests under which the DUT response (alternate diagnostic signature) exhibits strong simultaneous correlation with its specifications as well as the critical process or circuit parameters with virtually zero extra test-time or test-hardware cost. Simulation results indicate that critical process parameters can be diagnosed accurately from the applied tests.