At frequencies beyond 1GHz, every component of the IC package contributes to the RF performance, whether required or not. In this work, we study the effects of packaging materials namely, the substrate and the globtop/underfill material. The EGA and PSGA were area array CSPs chosen for characterisation. We used a measurement scheme with IMEC's MCM-D technology for accurate RF measurements. The different measurements made include the package interconnect, the wirebond and the influence of nine different globtop/underfill materials. We also performed 3D EM simulations on the wirebond with and without encapsulation. The main conclusion is that the losses due to impedance mismatch are higher than the material losses especially at higher frequencies. We also show evidence that the influence of globtop/underfill material is to lower the characteristic impedance of the line and this can be used to our advantage on wirebonds.
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