SEMICONDUCTOR DEVICES AND METHODS FOR THEIR FABRICATION

摘要

1292636 Semi-conductor device GENERAL ELECTRIC CO 8 Dec 1969 [9 Dec 1968] 59854/69 Heading H1K An encapsulation for a semi-conductor device comprises an electrically conductive heat sink 104 on to which a semi-conductor wafer 112 is bonded, and a header assembly 136 which retains connecting leads 140, 142, 144 in their respective positions to contact flanges 124, 126 and 132 respectively, forming the contacts to the wafer 112, the whole then being encapsulated and enclosed in an insulating casing. The semi-conductor device, which may be a diode, thyristor or triac protected peripherally by a glass layer, is provided on opposite major faces with a composite metal layer comprising two metal sublayers separated by a sublayer of soft solder as a shock absorber, and is bonded by one major face to the heat sink, and has bonded to its other major face electrodes 108, 122, with upstanding portions 124, 126. The heat sink, which may be fixed to a cooling fin assembly, has an upstanding grooved flange 132 over which the header assembly 136 is fitted so that the flange projects through aperture 138 in the header and the central lead 142 fits in the groove 134 in the flange 132. Leads 140, 144 then contact flanges 124, 126 and are soldered thereto, lead 142 being soldered simultaneously to flange 132. The device is then encapsulated with a fluid impervious material such as a synthetic resin, rubber, or particulate dielectric, and the whole is enclosed in a moulded casing, Fig. 2, not shown. In an alternative embodiment, the lead 142 fits in a hole in flange 132, Fig. 14 (not shown). In further embodiments the leads are supported by a solid block header assembly which fits on to the heat sink by a tab and slot arrangement, Fig. 15 (not shown), or are supported rigidly by parallel strips which are removed after encapsulation thus dispensing with the need for a header assembly, Fig. 13 (not shown).