Abstract: A method of fabricating a metallic hermetic sealing cover for a container comprises plating a strip of base metal with a material comprising preponderantly a precious metal such as gold to a thickness of 40% to 90% of the ultimate required minimum surface thickness, which may be 25 to 100 microinches, preferably about 40 microinches, dividing the strip into cover elements of predetermined size, and barrel-plating such cover elements with the plating material to provide a resultant minimum thickness of surface plating substantially equal to the required miniumum thickness.

Abstract: A prefabricated composite metallic plate unit for transmitting heat from a heat source to a heat-absorbing medium and having a relatively high heat-transfer coefficient comprises a pair of high-tensile-strength plate members of a cobalt-nickel-iron or similar type alloy having a temperature coefficient of expansion of about 6.2.times.10.sup.-6 /.degree.C. over a temperature range of about 30.degree. C. to 550.degree. C. and a tensile strength of at least 35 kg/mm.sup.2. A plurality of holes extend through each of the plate members and have an aggregate area of about 70% of the surface areas thereof, such holes numbering about 2000 per square inch. A layer of relatively malleable metallic material is interposed between the plate members and fills the holes. Such metallic material is a metal of the group consisting of copper, aluminum, gold, silver, and an alloy of any of such metals. The resulting composite metallic plate unit has a heat-transfer coefficient of at least about 0.3 cal./cm.sup.2 /cm/sec./.

Abstract: A method of fabricating a metallic hermetic sealing cover for a container comprises plating a strip of base metal with a material comprising preponderantly a precious metal such as gold to a thickness of 40% to 90% of the ultimate required minimum surface thickness, which may be 25 to 100 microinches, preferably about 40 microinches, dividing the strip into cover elements of predetermined size, and barrel-plating such cover elements with the plating material to provide a resultant minimum thickness of surface plating substantially equal to the required minimum thickness.

Abstract: A cover unit for hermetically sealing a container for a semiconductor device comprises a rectangular metallic cover element such as a cobalt-nickel-iron alloy and a plurality of contiguous turns of wire of a heat-fusible material such as a gold-tin eutectic alloy formed and disposed on the cover element with the outermost turn substantially in registry with the periphery thereof, said turns being spot-welded thereto substantially at the corners of the cover element. The preferred method of fabricating the foregoing hermetic sealing cover unit comprises disposing it in a shallow cavity of a rotatable nonconductive supporting member, such cavity having dimensions to retain the cover element in desired position and forming a flat single-layer multiturn wire winding of heat-fusible material by winding it on a mandrel in contact with the cover element and rotatable therewith and spot-welding the winding to the cover element at a plurality of spaced points.

Abstract: A cover unit for hermetically sealing a container for a semiconductor device comprises a metallic cover element, a preformed ring of substantially chemically unreacted thermosetting plastic and a preformed ring of an alloy consisting of about 63% tin and 37% lead having the characteristic that it solidifies from the fluid state as a homogeneous mixture and a relatively thin oxidation-resistant coating clad on the ring and consisting of about 96.5% tin and 3.5% silver. One of the rings is disposed substantially in registry with the periphery of the cover element and the other of the rings is nested closely inside the one ring. Each of the rings may be either rectangular or circular in cross-section. Upon heating the cover units, the two rings are fused to each other, to the cover element, and to the container being sealed.

Abstract: A cover unit for hermetically sealing a container for a semiconductor device comprises a rectangular metallic cover element such as a cobalt-nickel-iron alloy and a plurality of contiguous turns of wire of a heat-fusible material such as a gold-tin eutectic alloy formed and disposed on the cover element with the outermost turn substantially in registry with the periphery thereof, said turns being spot-welded thereto substantially at the corners of the cover element. The preferred method of fabricating the foregoing hermetic sealing cover unit comprises disposing it in a shallow cavity of a rotatable nonconductive supporting member, such cavity having dimensions to retain the cover element in desired position and forming a flat single-layer multiturn wire winding of heat-fusible material by winding it on a mandrel in contact with the cover element and rotatable therewith and spot-welding the winding to the cover element at a plurality of spaced points.

Abstract: A hermetic sealing-cover unit for a container for semiconductor devices is fabricated by applying to the cover a solution of a thermosetting plastic material in a drying solvent to form a thin plastic coating on the cover. The solution preferably is a 10% concentration by weight of epoxy resin in a solvent comprising a mixture of methanol, ethylene dichloride, and dioxane in the ratio of 50:35:15. The cover element is of a material impervious to moisture and air, preferably a material of the group which includes metal, glass, quartz, and ceramic. A sealing ring is formed of substantially chemically unreacted thermosetting plastic material, preferably the same as the plastic material of the cover coating, and is of a size substantially to register with the periphery of the cover. The ring is then pressed into engagement with the plastic coating on the cover at ambient temperature, while the coating is still tacky, and the drying of the coating on the cover is completed to adhere the ring to the cover.

Abstract: An hermetically sealed container for electronic devices comprises a supporting pad for an electronic device, a conductive lead frame surrounding the pad and forming therewith a unitary construction, and a sheet of homogeneous epoxy resin extending over and fused to each face of the frame and its conductive leads, at least one of the sheets having an aperture dimensioned and disposed to surround the supporting pad and a portion of the adjacent leads of the lead frame. The container further comprises upper and lower cover plates of a material of the group comprising metal, ceramic, glass, and rigid plastic fused to the plastic sheets, one of such plates having an opening in registry with the aperture in the adjacent one of the plastic sheets for receiving an electronic device to be supported on the pad. The container further comprises means for hermetically sealing the opening in such one of the cover plates, for example an upset cavity in the plate forming an integral portion thereof.

Abstract: A solder preform for hermetically sealing a cover to a container for a semiconductor package comprises a relatively thick flat ring of an alloy consisting of substantially 95% lead, 2.5% tin, and 2.5% silver, which alloy has the characteristic that it solidifies from the fluid state as a homogeneous mixture without substantial separation of the minority element crystals. The solder preform further comprises a relatively thin coating clad on each surface of the flat ring of an oxidation-resistant alloy, preferably an alloy consisting of substantially 96.5% tin and 3.5% silver.

Abstract: A conductive hermetic sealing cover for a container is fabricated by disposing the cover with a superimposed preformed heat-fusible conductive ring having outer dimensions similar to those of the cover in a shallow cavity of a nonconductive supporting member, the cavity having dimensions only slightly larger than those of the cover to secure registration between the ring and the periphery of the cover. A plurality of pairs of spaced electrodes are resiliently engaged with the ring with substantially equal contact pressures and a separate pulse of current is passed between the electrodes of each pair and through the ring and the cover, thereby producing an effective spot weld between the ring and the cover adjacent each of the electrodes. The term "ring" is used herein and in the appended claims in its generic sense to include a closed loop of conductive material of any configuration corresponding to the periphery of the cover, usually round or rectangular.

Abstract: A solder preform for hermetically sealing a cover to a container for a semiconductor package comprises a relatively thick flat ring of an alloy consisting of substantially 95% lead, 2.5% tin, and 2.5% silver, which alloy has the characteristic that it solidifies from the fluid state as a homogeneous mixture without substantial separation of the minority element crystals. The solder preform further comprises a relatively thin coating clad on each surface of the flat ring of an oxidation-resistant alloy, preferably an alloy consisting of substantially 96.5% tin and 3.5% silver.