Response surface methodology for modelling lead frame of IC packages

The response surface methodology (RSM) for modelling IC packages is presented. The segmentation of the lead frame of an IC package into simpler structures is applied in order to describe the package. The result of the segmentation is the lead frame described by using only two types of simplified lead frame model primitives. These simplified models are used in the 2^q experiment, i.e. a set of electromagnetic (EM) simulations is performed. Each EM simulation is done on the simplified lead frame structure. The per-unit-length (p.u.l.) parameters of the lumped element model are obtained by fitting the p.u.l. parameters to the S-parameters obtained by EM simulations. These extracted lumped element parameters depend on the geometrical data of the package and they are approximated by the first-order models. The final results of the presented methodology are the parameters of the lumped element model described by using closed-form equations that depend on the geometrical data as the input variables. These equations can be used to model the lead frames having different geometries without using time consuming EM simulations and subsequent parameter extraction. The presented methodology is demonstrated on the TQFP100 and SOIC14 lead frames.