Multilayer board having insulating isolation rings

摘要

A structure includes a support layer formed of a conductive material, such as a sheet of copper. The support layer has a number of conductive islands isolated from other portions of the support layer by isolation gaps. The support layer is sandwiched between two compound layers each of which is formed of a dielectric layer having a number of via holes and conductive elements located in the via holes. The conductive elements are formed at predetermined locations such that a conductive element in each compound layer contacts a conductive island in the support layer. The structure also includes two conductive layers formed on the two respective compound layers such that a trace in a first conductive layer is coupled to a trace in a second conductive layer through two conductive elements in the respective two compound layers and an island in the support layer. Such a structure can be formed by a number of processes. For example, the support layer can be formed by etching a sheet of conductive material, the compound layers can be formed by placing a conductive paste in via holes in a dielectric layer, and the conductive layers can be formed by lamination followed by etching to form traces.