Patent GB-1171655-A (GB)
Title: Method of Making Electrical Wiring and Wiring Circuit Connections between Conductors and the Electrodes of an Electrical Component
Inventor: IWATA SABURO
IPC: H01L23/057
Filed: 1967-02-23
Abstract: 1,171,655. Soldering. SONY K.K. 23 Feb., 1967 [26 Feb., 1966 (2)], No. 8725/67. Heading B3R. [Also in Divisions H1 and H2] In a method of making an electrical connection to a component, the component is provided with an electrode, and a conductive circuit pattern is formed on an insulating layer which is placed on the component so that the electrode is in register with a part of the pattern, solder being interposed between them, after which the assembly is heated to a temperature higher than the melting point of the solder to form a soldered connection between electrode and pattern. As shown, Fig. 4, a plurality of components 17, e.g. resistors, capacitors, inductors, having planar electrodes 18 are mounted on a base-plate 16 of glass, ceramic &c., and placed in a recess 26 in a positioning plate 25 of ceramic or heat-resistant resin, into which external leads 27 protrude. A conductive circuit pattern is formed on a thermoplastic board 19 of, e.g. low m.p. glass, fluorine resin, epoxy resin, polyethylene &c., as by vapour deposition or plating, either through a mask or with subsequent etching. For example, successive layers of Cr, Cu and Au may be deposited, or Ag on Ni, or Pt, Au or Ag on " Kovar " (Registered Trade Mark). Alternatively, a conductive paint such as Ag paste may be employed. The conductive pattern comprises enlarged terminal areas joined by strips, which may be covered with a protective layer; moreover, a strip 23 may be located within the board 19, or on the opposite face thereof from the rest of the pattern. Solder 24 is applied to the terminal areas of the pattern by vapour deposition or dip-soldering; alternatively, the solder is applied to the electrodes 18. Board 19 is now placed in the cavity 26 in plate 25, the terminal areas being in register with and facing electrodes 18 and the ends of leads 27, and the assembly is heated to soften the board 19 so that it sags down, as shown in Fig. 5, until the terminal areas contact the electrodes 17 and leads 27 and are soldered thereto. The positioning plate 25 may be removed, or retained to form part of a sealed casing for the components 17. Soft solder having an m.p. of c. 150 C. may be used, or a Ag-Sn alloy (m.p. = c. 220 C.) or a Bi-Sn alloy (m.p.=c. 139 C.). In an alternative embodiment (Figs. 9, 10, not shown), the circuit pattern is formed on a flexible membrane (40), e.g. of paper or synthetic resin film which, after the deposition of the solder, is coated with a rosin flux and pressed down on to the components by means of a heatproof, resilient member (43) of silicone rubber, fluorinated resin &c., while the assembly is heated to effect soldering. On cooling, the membrane (40) may be removed, the components and circuit pattern being sealed with resin, glass &c. To form connections to a multielectrode integrated circuit device, insulating spacers are provided in the positioning plate around the device, standing proud thereof, to prevent short-circuiting.