On-Chip Detection of Process Shift and Process Spread for Silicon Debugging and Model-Hardware Correlation

This paper proposes the use of ROs (Ring Oscillators) for process shift and process spread detection for silicon debugging and model-hardware correlation. ROs are designed to be sensitive to either nMOSFET orpMOSFET variation, thus the location of the chip in the process spacecan be detected directly from the RO measurements. Test chip measurements in a 65-nm process shows the validity of the proposed ROs. Amounts of process shift and process spread for key process parameters as threshold voltages and gate length are extracted from test chip measurements.