Analytical modeling and characterization of deep-submicrometer interconnect

Abstract

This work addresses two fundamental concepts regarding deep-submicrometer interconnect. First, characterization of on-chip interconnect is considered with particular attention to ultrasmall capacitance measurement and in-situ noise evaluation techniques. An approach to measuring femto-Farad level wiring capacitances is presented that is based on the concept of supplying and removing charge with active devices. The method, called the charge-based capacitance measurement (CBCM) technique, has the advantages of being compact, having high-resolution, and being very simple. We also present a novel time-domain measurement scheme for on-chip crosstalk noise that is based on the use of cascaded high-speed differential pairs to compare a user-defined reference voltage to the unknown noise peak value. The noise measurement technique complements a delay measurement to directly evaluate the impact of capacitive coupling on delay for various victim and aggressor driver sizes as well as arbitrary waveform timing and phase alignments. The second area of emphasis in this work is analytical interconnect modeling. Several important effects are modeled, including a rigorous crosstalk noise model that also includes a timing-level model. Results from this noise model show it to provide accuracy within 10% of SPICE for a wide range of input parameters. The noise model can also be calibrated and verified with comparison to the noise measurement scheme described in this work. A fast Monte Carlo approach to modeling the circuit impact of back-end process variation is presented providing a better depiction of real 3-/spl sigma/ performance spreads compared to the traditional skew-corner approach. Finally. A comprehensive system-level performance model called Berkeley Advanced Chip Performance Calculator (BACPAC) is developed that accounts for a number of relevant deep-submicrometer system design issues. BACPAC has been implemented online and is useful in exploring the capabilities of future very large scale integration systems as well as determining trends and tradeoffs inherent in the design process.