JPS502232B1 - - Google Patents

Abstract

1,186,890. Semi-conductor devices. MOTOROLA Inc. 12 June, 1967 [13 July, 1966], No. 27058/67. Heading H1K. A semi-conductor device is mounted on a plate and is encapsulated with plastics material so that the plate forms one face of the encapsulation, the plate and the encapsulation having an aperture extending therethrough, the arrangement having lead members, one of which is integral with the plate, extending from the encapsulation in a plane parallel to, but offset from, that of the plate. As shown, Fig. 6, the leads 18, 23 and 24 and the plate 12 are formed integrally together with supporting strips 53 and 55 from a sheet of copper plated with nickel. The plate 12 is formed as an extension of the centre lead 18, and the ends of the two outer leads 23, 24 are flattened to form bonding areas 27, 28. As shown, Fig. 2, a silicon transistor die 26 is mounted with its collector region in contact with plate 12, the emitter and collector electrodes are connected by fine wires (34, 35) to bonding areas 27, 28, and epoxy resin is transfer moulded over the top of the plate to encapsulate the ends of the leads 23, 24 and the die 26. The leads are then separated from supporting strip 53 and the parts of strip 55 between the leads are also removed. Plate 12 has side members 21 which extend into the encapsulation 14 to improve the adhesion, and has an aperture 31 which is aligned with an aperture 33 in the encapsulation 14 so that the device can be bolted to a heat sink. The leads lie in a plane offset from that of plate 12 so that they do not contact the heat sink. A plurality of devices can be sequentially mounted and connected and then simultaneously encapsulated by forming a plurality of sets of leads structures connected together by the supporting strips (53, 55), Figs. 3, 4 and 5 (not shown). Strip 53 is provided with groups of apertures 54 by means of which the strip can be moved through assembly machinery.