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.