Method and device for making connections in transistors

摘要

842,957. Transistors. SYLVANIA ELECTRIC PRODUCTS Inc. Sept. 8, 1958 [Sept. 13, 1957], No. 28776/58. Class 37. A clip, Fig. 1, for use in a method of bonding a power transistor to a relatively massive heatdissipating block and to leads insulatedly sealed therethrough, is made of copper or brass, which may be gold plated, and comprises a support portion 12 with down-turned legs 13, 14, and two arms 15, 16 at the ends of which are formed connector members 19 and 22, the centre part of 19 being raised. A transistor, Fig. 7, comprising a wafer 31 of semi-conductor material, e.g. silicon or germanium, having an indium dot (not shown) alloyed centrally to each surface to form emitter and collector electrodes, and an annular base electrode 32 of "Kovar" (Registered Trade Mark), preferably solder-covered, is placed in the clip so that a contact member 21 at the end of connector member 19 bears upon the emitter electrode and an arcuate contact member 23 on connector member 22 is held in close contact with the base electrode by bent over tabs 24-26. The assembly is placed on a block 41, preferably of copper, the collector electrode being placed on an upstanding pedestal located centrally on the block, and leads 43, 44, which enter the block via glass-to-metal seals 47, abutting arcuate surfaces 17, 18 of connector members 19, 22 respectively. Solder discs (not shown) are placed over leads 43, 44, and the assembly is heated in a reducing atmosphere to solder the leads to the connector members and to bond the electrodes to the contact members and the pedestal. The arms 15, 16 are then severed and removed with support 12. Finally, a domed cap is welded to the block. In another embodiment the clip is small enough to remain inside the finished device, the legs 13, 14 being turned up out of contact with the block and the support member 12 being cut across.