Semi-analytical techniques for substrate characterization in the design of mixed-signal ICs

A number of methods are presented for highly efficient calculation of substrate current transport. A three-dimensional Green´s Function based substrate representation, in combination with the use of the Fast Fourier Transform, significantly speeds up the computation of sensitivities with respect to all parameters associated with a given architecture. Substrate sensitivity analysis is used in a number of physical optimization tools, such as placement and trend analysis for the estimation of the impact of technology migration and/or layout re-design.