A package analysis tool based on a method of moments/surfaceformulation

摘要

A package analysis tool is described which is based on a method ofmoments analysis and surface formulation. The surface formulationreplaces ideal conductors by electric currents on their surfaces;electric and magnetic currents are used for lossy conductors. Thesecurrents are then discretized using triangular linear currentapproximations, with the primary advantage of being able to representarbitrary shapes. Frequency dependent inductance and resistance arecomputed using a novel approach. The capacitance is also computed usingpiecewise constant charge distributions on each triangle. The currentand charge distributions are compatible, and therefore transmission linemodelling can be done accurately. The algorithm enables use of the toolfor both transmission line and discontinuity modelling, as well asinductance evaluation for analysis of simultaneous switching noise. Thetool has a graphical pre- and post-processor, which allows analysis ofhighly irregular structures, as are found in most practical packagingconfigurations. In this paper, the algorithms for the tool aredescribed. Comparisons are shown between results obtained using theapproach of the paper and analytical and approximate calculations.Comparison is also shown with measured capacitance for irregular shapes.The analysis of simultaneous switching noise for a 304 lead, six layersingle chip module is described