Substrate optimization based on semi-analytical techniques

Several methods are presented for highly efficient calculation of substrate noise transport in integrated circuits. A three-dimensional Green’s function-based boundary element method, accelerated through use of the fast Fourier transform, allows the computation of sensitivities with respect to all substrate parameters at a considerably higher speed than any methods reported in the literature. Substrate sensitivities are used in a number of physical optimization tools, such as placement and trend analysis. The aim is a fast and accurate estimation of the impact of technology migration and/or layout redesign on substrate noise and, ultimately, on the circuit’s overall performance. The suitability of the approach is shown through industrial-strength mixed-mode integrated circuits fabricated on a standard CMOS process.