Method of fabricating a multilayer circuit board assembly

A method of fabricating a multilayer microwave circuit board assembly comprising the steps of:

• A. providing a plurality of individual circuit boards wherein each board is prepared by:
• (1) applying a first conductive layer on a facing surface of a suitable non-conductive substrate material;
• (2) applying a second conductive layer on an opposite facing surface of the substrate material;
• (3) forming at least one hole through the substrate material and said first and second conductive layers;
• (4) depositing a conductive layer over said first and second conductive layers sufficient to also be deposited onto the sidewall surfaces of each said formed hole to establish an electrical interconnection between said first and second conductive layers;
• and
• (5) depositing a conductive bonding material onto said previously deposited conductive material;
• B. stacking said plurality of prepared circuit boards in a pre-determined order and orientation to form an assembly, adjacent circuit boards of the assembly being separated by a dielectric bonding layer material having apertures therethrough to insure an electrical interconnection between adjacently oriented boards at the aperture positions;
• and
• C. applying heat and pressure to the thusly stacked circuit boards to effect an integrally bonded and interconnected circuit board assembly.