Abstract 975,987. Semi-conductor devices. SIEMENSSCHUCKERTWERKE A.G. July 11, 1962 [July 14, 1961], No. 26729/62. Heading H1K. In a process for producing a semi-conductor device a carrier plate is connected to one flat face of a monocrystalline semi-conductor wafer, e.g. of silicon or germanium, and a gold foil is alloyed to the other flat face of the wafer forming an electrode of the gold-semi-conductor eutectic after which a second carrier plate with a silver coating thereon is applied to the electrode and the assembly is subjected to heat and pressure at a temperature below the melting point of the gold semi-conductor eutectic to unite the carrier plates together. In the embodiment the carrier plate 2 which may be of molybdenum, or tungsten is joined to a P-type silicon wafer by a layer of aluminium 4 and a gold antimony foil 5 is then applied to the other flat face of the wafer. The exposed surfaces of the wafer 4 may be etched and then coated with a protective lacquer, e.g. silicon lacquer having an addition of alifarin prior to the uniting of the carrier plates. Further, before uniting the surfaces of silver and gold-semi-conductor eutectic, they may be surface lapped. A silver coating may be applied to the outer surfaces of the carrier plates for soldering to external cooling members. The surface of the silver layer to be united with the eutectic electrode may be formed with protuberances which are lapped so that they all lie in a plane forming a system of channels which become filled with a cast resin 8 once the parts 5 and 7 are united.
THE METHOD OF PRODUCING AN ELECTRICALLY ASYMMETRICAL SEMICONDUCTOR DEVICE OF SUBSTANTIALLY SYMMETRICAL MECHANICAL DESIGN WHICH COMPRISES THE STEPS OF PRODUCING A SEMICONDUCTOR SUBASSEMBLY FROM A MONOCRYSTALLINE SEMICONDUCTOR PLATE WITH AN ALLOY-BONDED CARRIER METAL PLATE HAVING A THERMAL COEFFICIENT OF EXPANSION SUBSTANTIALLY SIMILAR TO THAT OF THE SEMICONDUCTOR PLATE ON ONE SIDE THEREOF AND AN ALLOYED GOLD-SEMICONDUCTOR EUTECTIC ALLOY ELECTRODE ON THE OPPOSITE SIDE; COVERING A SECOND CARRIER METAL PLATE HAVING A THERMAL COEFFICIENT OF EXPANSION SUBSTANTIALLY SIMILAR TO THAT OF THE SEMICONDUCTOR PLATE ON AT LEAST ONE FLAT SIDE WITH A LAYER OF SILVER; PLACING THE SILVER-COVERED SIDE OF THE SECOND CARRIER PLATE INTO FACETO-FACE CONTACT WITH THE GOLD ALLOY ELECTRODE; AND SUBJECTING THE ENTIRE ASSEMBLY FOR SEVERAL HOURS TO A PRESSURE OF BETWEEN ABOUT 200 KG./CM.2 TO ABOUT 400 KG./CM.2 AND SIMULTANEOUS HEATING TO A TEMPERATURE OF ABOUT 200*C. TO 300*C.
Claim 2
Independent Claim
142 words
THE METHOD OF PRODUCING AN ELECTRICALLY ASYMMETRICAL SEMICONDUCTOR DEVICE OF SUBSTANTIALLY SYMMETRICAL MECHANICAL DESIGN WHICH COMPRISES THE STEPS OF PRODUCING A SEMICONDUCTOR SUBASSEMBLY FROM A MONOCRYSTALLINE SEMICONDUCTOR PLATE WITH AN ALLOY-BONDED CARRIER METAL PLATE HAVING A THERMAL COEFFICIENT OF EXPANSION SUBSTANTIALLY SIMILAR TO THAT OF THE SEMICONDUCTOR PLATE ON ONE SIDE THEREOF AND AN ALLOYED GOLD-SEMICONDUCTOR EUTECTIC ALLOY ELECTRODE ON THE OPPOSITE SIDE; COVERING A SECOND CARRIER METAL PLATE HAVING A THERMAL COEFFICIENT OF EXPANSION SUBSTANTIALLY SIMILAR TO THAT OF THE SEMICONDUCTOR PLATE ON AT LEAST ONE FLAT SIDE WITH A LAYER OF SILVER; PLACING THE SILVER-COVERED SIDE OF THE SECOND CARRIER PLATE INTO FACETO-FACE CONTACT WITH THE GOLD ALLOY ELECTRODE; AND SUBJECTING THE ENTIRE ASSEMBLY FOR SEVERAL HOURS TO A PRESSURE OF BETWEEN ABOUT 200 KG./CM.2 TO ABOUT 400 KG./CM.2 AND SIMULTANEOUS HEATING TO A TEMPERATURE OF ABOUT 200*C. TO 300*C.