GB1313871A - Semiconductor devices - Google Patents

Abstract

1313871 Semi-conductor devices MULLARD Ltd 1 July 1970 [16 March 1970] 12507/70 Heading H1K A supply conductor 12 is connected to an electrode 17 on a semi-conductor body 10 via an open-sided, electrically conductive interconnection member 13 of generally annular configuration which includes spaced, discrete contact portions 14 at one level secured to the electrode 17 and further spaced, discrete contact portions 19 at a second level secured to the end of the supply conductor 12 either directly or through a platform member 15. The interconnection member 13 preferably comprises an annulus, e.g. of Cu or Au-plated Ag, mechanically deformed into a stepped configuration. In the Si thyristor shown an Au-plated Ag gate lead 21 passes down through central apertures in the Cu platform member 15, the interconnection member 13 and the Au-plated Mo electrode plate 17 to contact the gate region centrally. The electrode plate 17 is soldered to Au-plated Ni metallization on the Si surface. The Si body 10 is soldered to a Mo disc 24 on a Cu header 25. Au-Ge and Au-Sn solders are used to assemble the structure. The thyristor body 10 includes multiple cathode-emitter shunts and has its edge doubly bevelled at angles of 4¢ and 20 degrees. The open-sided structure of the interconnection member 13 prevents the accumulation of pockets of etchant when the body 10 is etched and rinsed after assembly. Silicone rubber 27 protects the edge of the body 10.