First Look at Across-chip Performance and Process Noise Using Non-Contact, Performance-Based Metrology

We report on the first non-contact, non-destructive performance measurements of embedded Ring Oscillators. Measurements are made inside the die active area as early as Metal 1. 90-nm logic CMOS technology was used for this work. We have measured residual across-field performance process noise, and variation separate from and of opposite sense to wafer uniformity. This effect cannot be extrapolated from scribe measurements.