Patent GB-1430666-A (GB)
Title: Connections for semiconductor components
IPC: H01L21/60
Filed: 1973-10-24
Abstract: 1430666 Semi-conductor devices ESEC SALES SA 24 Oct 1973 [26 Oct 1972] 49518/73 Heading H1K In an apparatus (Fig. 1) continuously applying wire connections in succession to semiconductor devices, e.g. a transistor 1, the semiconductor chip 4 is secured to a substrate 2 over a metal electrode, e.g. a collector connection, and the substrate has connecting pins 5, 6 for the base, and emitter electrodes over wires 7<SP>1</SP>, 8<SP>1</SP> attached by thermal compression of a sphere of the end of each wire to the appropriate electrode and pin. Dies 9, 10; 11, 12 movable together to and from the transistor are provided for each connecting wire 7<SP>1</SP>, 8<SP>1</SP>; one of which (9 or 11) being recessed to accommodate the sphere on the wire end and the other of which (10 or 12) is either flat or also recessed to accommodate a sphere. Die 9 or 11 is obliquely faced and grooved to retain part of wire 7<SP>1</SP>, 8<SP>1</SP>; with an aperture leading to a retaining vacuum. The semi-conductor devices are arranged on a horizontally movable conveyer (not shown). Wires 13, 14 (e.g. gold) are paid out over brakes 15, 16 through capillary tubes 17, 18 to a fuse-off device with flame 21, 22 periodically acting on the wire (alternatively a plasma flame or arc may be used). The wire 13, 14 is clamped by vacuum to holders 23, 24, mechanically interconnected with the capillary tubes 17, 18 for axial displacement of the wire, while the holders are independently displaceable perpendicular to the axis; the motions of the holders and dies being obtained by cams (not shown). In operation, at a predetermined instant, dies 9, 10; 11, 12 respectively impress the wire end spheres on the chip 4 in the required positions P3, P4 and also impress the remaining spheres on pins 5, 6; the component 1 being heated to 300-360 C. to achieve mechanical and electrical connection. Simultaneously the pay-out wires with fused end spheres are positioned at P 1 , P 2  at a pre-set distance from the required positions P 3 , P 4  and flamed at 21, 22 to produce a detached sphere ended piece of the required length which is held at 23, 24 while wire supply 13, 14 is held by capillaries 17, 18. Thereafter, dies 9, 10; 11, 12 are raised and separated (Fig. 2) and holders 23, 24 are translated downwards, while the semi-conductor component 1 with wire connections is removed by the conveyer and a further component is presented (Fig. 1). Capillaries 17, 18 are displaced axially towards dies 9, 10; 11, 12 over distances B 1 , B 2  and wire 13, 14 is paid out from the supply until the end sphere is positioned at P 1 , P 2  (Fig. 3) and the wire is held by brake 15, 16. As capillary 17, 18 advances, holders 23, 24 are also displaced over distance B 1 , B 2  to a new position wherein the wire end spheres register with dies 9, 10; 11, 12 perpendicularly to the axis. The holders are then displaced perpendicularly to the axis so that a sphere rests in a recess of dies 9, 11 and the wire rests in the groove thereof by vacuum retention. The holders and capillaries are removed leaving the wires in situ (Fig. 4) and the dies 9, 10; 11, 12 are lowered to attach the sphere ends to the electrodes and pins by thermocompression. Simultaneously further wires are prepared by fusion (Fig. 1) and the process is recommenced for a third semi-conductor device presented by the conveyer. The cam drives for dies 9, 10; 11, 12; capillaries 17, 18 and holders 23, 24 also operate valves for vacuum in dies 9, 11 and holders 23, 24. The conveyer may be controlled mechanically, electrically, pneumatically or hydraulically for complete automation, with light projection manipulation control for setting the semi-conductor devices accurately on the conveyer. The process is also applicable to single wire connections, e.g. for luminous diodes. The wire connections may be angled or of different lengths.