A design-oriented methodology for accurate modeling of on-chip interconnects

An accurate modeling methodology for typical on-chip interconnects used in the design of high frequency digital, analog, and mixed signal systems is presented. The methodology includes the parameter extraction procedure, the equivalent circuit model selection, and mainly the determination of the minimum number of sections required in the equivalent circuit for accurate representing interconnects of certain lengths within specific frequency ranges while considering the frequency-dependent nature of the associated parameters. The modeling procedure is applied to interconnection lines up to 35 GHz obtaining good simulation-experiment correlations. In order to verify the accuracy of the obtained models in the design of integrated circuits (IC), several ring oscillators using interconnection lines with different lengths are designed and fabricated in Austriamicrosystems 0.35 μm CMOS process. The average error between the experimental and simulated operating frequency of the ring oscillators is reduced up to 2% when the interconnections are represented by the equivalent circuit model obtained by applying the proposed methodology.