Monolithic implementation of coaxial line on silicon substrate

A coaxial line has been monolithically fabricated on silicon substrate usin g Benzocylobutene (BCB) for dielectric spacers. Because of its closed struc ture, it is an effective interconnection method to reduce parasitic radiati on and coupling effect. The fabricated coaxial line with 2 mm length has hi gh isolation (<-60 dB), low attenuation (<0.08 dB/mm) and low return loss ( <-32 dB) in the range of 1 GHz-20 GHz, It can be easily fabricated using st andard silicon IC technologies, and requires no wafer thinning and backside processing In view of cost performance and integration density, the coaxia l line on low-resistivity silicon is shown to be suitable for RF interconne ct and multichip module (MCM) package applications.