Crosstalk-based capacitance measurements: theory and applications

Geometry scaling increases the relative effect of coupling capacitances on performance, power, and noise so that they need to be carefully taken into account during process development, characterization, and monitoring. In the last decade, charge-based capacitance measurements (CBCMs) have been widely used to estimate on-chip wiring and coupling capacitances because of their accuracy and simplicity. We provide a thorough theoretical and experimental study of CBCMs applied to the selective extraction of cross-coupling capacitances. We take a historical perspective starting from the original CBCM approach proposed by Chen in 1996, and we present a new technique for crosstalk-based capacitance measurements (CTCMs). CTCMs improve the accuracy and usability of CBCMs while reducing the complexity of the test structures. We present the theory of CTCM, we provide experimental results demonstrating its improved accuracy, and we discuss its application to a wide range of process monitoring and testing tasks. Experimental results are used throughout the paper to support the discussion.