Calibration of interconnect corners using on-chip ring oscillators

Interconnect corners should accurately reflect actual interconnect in silicon to ensure proper design signoff. On-chip ring oscillator (ROSC) based calibration of interconnect corners is proposed. It comprises extraction of ROSC delay as a function of interconnect resistance and capacitance, projection of measured delay on that function, and identifying how existing corners should be adjusted. Simulation using a new calibrated corner demonstrates an excellent match with measurement in 14-nm test chips.