Methods of fabrication of coaxial vias and magnetic devices

Abstract

Methods are described for fabricating devices having vias containing more than one electrical conductor, in particular coaxial electrical conductors. A plurality of wires are bonded to a first substrate, such as a copper wire to a copper substrate. A second substrate having through-holes with side walls covered with an electrical conductor is disposed over the first substrate so that the wires are within the through-holes and spaced apart from the side walls. The first substrate is spaced apart from the second substrate by dielectric spacers. A polymer is injected into the space between the first and second substrates to provide electrical isolation therebetween. A polymer is injected into the space in the via between the elongated conductors and the conductive sidewall to provide dielectric isolation therebetween. The second substrate has electrically conductive pattern on both sides which are electrically interconnected by the electrically conductive sidewall to form an inner coil of electrical conductors. The first substrate is patterned to form an electrical conductive pattern. A pattern of electrical conductors is formed on the dielectric material on the side of the second substrate opposite the patterned first substrate and is electrically connected therewith through the elongated conductors on the through-hole to form an outer coil of electrical conductors around the inner coil of electrical conductors to from a transformer or an inductor.