Abstract: A technique for enclosing microelectronic circuit elements in hermetically sealed packages comprising a planar ceramic substrate with a box-like ceramic cover sealed thereto by a fused glass coating. The glass sealant is applied to the substrate in the form of a paste which thereafter is fired at high temperature and cooled to produce a smooth glass coating. With the cover in place on the substrate, the glass coating is remelted by heat developed by infra-red radiation developed by four line-focussed radiant heaters at the four sides of the package. The radiation of each heater is focussed at the interface line between the cover and the substrate. Because the radiant heat is concentrated along the interface line, unwanted heat transfer into the package is minimized, and the temperature is prevented from rising sufficiently to damage heat-sensitive elements.

Abstract: A miniaturized thick-film isolation transformer comprising two rectangular substrates each carrying successive screen-printed thick-film layers of dielectric with spiral planar windings embedded therein. The spiral windings comprise conductors formed of fused conductive particles embedded within a layer of dielectric insulating means solidified by firing at high temperature to form a rigid structure with the windings hermetically sealed within the dielectric and conductively isolated from each other within the transformer. The substrates are formed at opposite ends thereof with closely adjacent connection pads all located at a single level to accommodate automated connection making. Connections between the pads and the windings are effected by conductors formed of fused conductive particles. The substrates and the dielectric layers are formed with a central opening in which is positioned the central leg of a three-legged solid magnetic core.

Abstract: A technique for enclosing microelectronic circuit elements in hermetically sealed packages comprising a planar ceramic substrate with a box-like ceramic cover sealed thereto by a fused glass coating. The glass sealant is applied to the substrate in the form of a paste which thereafter is fired at high temperature and cooled to produce a smooth glass coating. With the cover in place on the substrate, the glass coating is remelted by heat developed by infra-red radiation impinging on all sides of the package structure from heaters in an infra-red furnace. A reflective shield on top of the cover reduces the inflow of heat through that surface, and a heat sink beneath the substrate removes heat, thereby to reduce the temperature rise experienced by circuit elements in the package interior.