An Invariant Interconnect Delay Monitoring Circuit for 3D System Scaling

In this study, we analyze the limitations of current ring-oscillator (RO) circuits in detecting AC resistance of interconnects. We propose an RC-delay-time amplifier (RCTA) and a delta-measurement method to separately measure resistance and capacitance while maintaining noise invariance. Additionally, we introduce a test circuit utilizing a Time-to-Digital Converter (TDC) for frequency-independent AC resistance detection. Simulation results demonstrate that our approach enhances resistance and capacitance separation, improving performance by 2.4 and 2.6 times, respectively, based on SNR analysis. This circuit is crucial for applications where interconnect RC delay is critical in system scaling transitions.