Abstract: An all-metal microwave chip carrier is provided with subminiature ceramic feedthroughs, each configured to function as a coaxial cable having a predetermined impedance. In one embodiment, the feedthroughs are formed by providing ceramic tubing metallized inside and out in which the ends are cut away to provide half-cylindrical bonding pads. In order to permit bonding directly to the feedthrough, a flat wire lead is soldered to the channel in the ceramic tube, with the ends of the flat wire extending onto the flat portions of the half-cylindrical portions of the feedthrough. In one embodiment, the chip carrier includes a base, ring, and stepped lid, all of Kovar or other suitable material, with the lid being weldable to the ring rather than being brazed or soldered.

Abstract: A brazing technique is described for providing a standard flat pack with a Thermkon base brazed to a Kovar frame through the utilization of an intermediary ring of high thermal conductivity material which prevents flashing onto the Thermkon base. Brazing is accomplished either in a one-step process in which the parts with the intermediary ring are brazed together all at one time with a single heat treatment, or in a two-step process in which the intermediary ring is first brazed to the frame. In a subsequent step, the frame with the intermediary ring brazed thereto, is brazed to the Thermkon base. In either process, the high thermal conductivity of the intermediary ring permits the ring to quickly reach brazing temperature for minimizing flashing.