Characterization of bump arrays at RF/microwave frequencies

A systematic procedure for the characterization of complex bump configurations at RF and microwave frequencies, is presented. Beginning with simple arrangements-single- and two-coupled bumps-full-wave electromagnetic (EM) field analysis, circuit simulations and RF measurements were used for the development and validation of their respective equivalent circuit models. These models were then extended to characterize three-coupled bumps, both in linear and triangular configurations. Finally, a combination of all the electrical parameters obtained from these simple bump configurations was used to characterize a complete bump array, taking into consideration that for pitches used in most high-speed packages, EM coupling between a bump and its “next but one” neighbor can be neglected.