The structure is converted into a unique triaxial via by etching a hole within what was the center post FIG. This results in a three conductor via with 50 a as the inner or signal conductor, 52 as the middle or inner shield conductor and 60 a as the outer shield conductor, all of which are electrically independent of each other. As previously illustrated, the process flow is exactly the same as for the aforementioned coaxial structure.
The main difference resides in a pattern being etched at the beginning of the process. Patterning the structure at the first lithography step with a third recess enables forming a third conductor in the substrate. It is worth noting that additive concentric rings may be added to a fourth and a fifth conductor.