RF characterization and modeling of various wire bond transitions

This paper presents radio-frequency (RF) characterization and modeling of various wire bond transitions between chips and packages. Test modules composed of Si chips and alumina packages are fabricated in conductor-backed (CB) structures, and they are characterized at frequencies up to 20 GHz. It is shown that the parallel plate resonance of the CB coplanar waveguide (CPW) persists in wire bonding transitions, and narrower-ground CPW-CPW transitions show better characteristics than wider-ground CPW-CPW transitions. The results of three-dimensional full-wave electromagnetic simulation on the test modules reproduce the measured results with a reasonable accuracy. Simple equivalent circuit modeling can reproduce the measured results of the narrower ground CPW transition with no resonance structures. Finally, the effects of bond wire length and impedance mismatch on RF performance are investigated.