Abstract: Pre-fired ceramic substrates are elected according to the desired electrical performance of the filter. If necessary for enhanced performance, the surfaces of the substrate may be lapped to assure that their top and bottom surfaces are parallel and their surface finish is smooth. The top surface of a lower layer is coated with a conductive film using thick film techniques then patterned to define the filter trace pattern. For precise dimensional control, photolithographic techniques may be used. The bottom and the sides of the lower layer are coated with the same conductive film. A seal glass which has a coefficient of thermal expansion which is matched as closely as possible to that of the ceramic substrate is screen printed onto the top surface of the lower layer. The top of the upper layer is screen printed with the conductive film and the bottom of the upper layer is coated with the seal glass. The upper and lower layers are bonded together by clamping them together and firing the seal glass.

Abstract: The invention is directed to a process for refurbishing of prior used laminated ceramic packages with the example shown as a pin grid array ceramic package which includes a ceramic substrate with a central opening or cavity, a plurality of conductors are embedded therein in one or more layers which have electrical condtinuity from the outer edge thereof to the central opening (this continuity path may extend through one or more layers) and to an equal plurality of conductive pads on the surface of the substrate.

Abstract: Pre-fired ceramic substrates are elected according to the desired electrical performance of the filter. If necessary for enhanced performance, the surfaces of the substrate may be lapped to assure that their top and bottom surfaces are parallel and their surface finish is smooth. The top surface of a lower layer is coated with a conductive film using thick film techniques then patterned to define the filter trace pattern. For precise dimensional control, photolithographic techniques may be used. The bottom and the sides of the lower layer are coated with the same conductive film. A seal glass which has a coefficient of thermal expansion which is matched as closely as possible to that of the ceramic substrate is screen printed onto the top surface of the lower layer. The top of the upper layer is screen printed with the conductive film and the bottom of the upper layer is coated with the seal glass. The upper and lower layers are bonded together by clamping them together and firing the seal glass.