Patent ID: 7549136

Claim:
A computer implemented method of approximating intrinsic capacitance of an integrated circuit (IC) block, comprising: dividing said IC block into a plurality of leaf cells that are categorized into groups; estimating an N-well capacitance associated with said IC block to obtain an N-well capacitance estimate; estimating a metal grid capacitance associated with said IC block to obtain a metal grid capacitance estimate; estimating a non-switching circuitry capacitance associated with said IC block to obtain a non-switching circuitry capacitance estimate; and estimating a total intrinsic capacitance associated with said IC block based on said estimates of N-well capacitance, metal grid capacitance and non-switching circuitry capacitance, wherein at least one of said estimates is obtained by estimating on a leaf cell basis and extrapolating to an entire group to obtain a respective group estimate, then aggregating said group estimates.