FDTD ANALYSIS OF HIGH-FREQUENCY ELECTRONIC INTERCONNECTION EFFECTS

A full-wave analysis of coupled high-frequency interconnect discontinu ities is presented using the finite-difference time-domain (FDTD) meth od. The electromagnetic effects of two via holes on microstrip lines i n close proximity to one another are examined and equivalent circuits are presented. The effects of two adjacent lines with bond wires, used , for example, to connect a die to the leadframe of an integrated circ uit (IC) package are also analyzed. Frequency domain results are prese nted by using the discrete Fourier transform of the time-domain result s, Guidelines regarding the effective use of the FDTD code including t he use a priori calculated electric field distribution in the excitati on plane, and the use of a weighted epsilon(r,eff) to minimize reflect ions at the absorbing boundaries are described. The obtained FDTD resu lts and the developed equivalent circuit models show the importance of radiation effects at frequencies beyond 20-30 GHz, the possibilities of reducing the inductive effect of bond wires by using two parallel b ond wires instead of one, and the importance of including mutual induc tance elements in the equivalent circuit model to account for the cros stalk between parallel vias across a ground plane.