Abstract: The present invention discloses a fabrication method and structure of spiral RF inductor on porous glass substrate. Thick porous silicon layer is natively formed on a silicon wafer by anodic etching the silicon material to a high degree of porosity. The porous silicon is than thermally oxidized at high temperature converting it into porous glass texture. The oxidation rate can be rapid due to open pore character of the etched structure, which allows oxidizing agents to penetrate deeply into the wafer. If the porosity is large enough, the pores will not be sealed by the expansion of oxide during the oxidation, which results a porous structure of glass-and-air mixture of low relative dielectric constant slightly over a value of 2. The final holes appear on the wafer surface can be sealed by CVD coating step, if necessary. This ultra-flat, low-k, silicon-based substrate allows RF spiral inductor to be made on its surface with excellently low loss, or high Q value.