Patent GB-926022-A (GB)
Title: Improvements in and relating to the manufacture of semiconductor devices and the like
IPC: H01L21/00
Filed: 1960-05-04
Abstract: 926,022. Making hermetic closures. PHILCO CORPORATION. May 4, 1960 [May 4, 1959], No.15736/60. Class 39 (2). [Also in Group XXX] Apparatus for the manufacture of hermetic closures, especially transistor stem assemblies, having a metallic housing bonded to a core of glass-like insulating material traversed by at least one lead-in wire comprises an indexing feed mechanism including transfer means carrying a plurality of dies to receive the housings and wires which are brought successively into position for depositing the housings in the dies, feeding a length or lengths of wires to each housing, supplying a charge of vitrifiable glasslike material to each housing and compacting this into a coherent mass, and means for fusing the material to form the whole into a unit. The apparatus comprises an indexing turntable 13, Fig. 1, carrying dies 15, housings being fed to the dies at 17, a lead or leads being inserted at 18, the housing being filled with powdered glass at 19, the filling compressed at 20, and the filled housing transferred at 21 to a set of fusing fixtures on a conveyer 173 whence they are carried through a furnace 23 being finally discharged down a shoot. The operation of the various mechanisms is controlled by the drive of the conveyer 173. The housings are fed from a vibrating hopper 25 down a track 26 at the end of which they are picked up by fingers on a plunger 32, Fig. 3, which pass through lead holes in the base of the housing. The plunger is operated by a double-acting piston 33, downward movement of which is effected by admitting compressed air to the space 35 above the piston under control of a microswitch operated by the ram for compressing the glass powder filling. A microswitch 42 is activated by the plunger when the finger has engaged the housing and operates an air cylinder 43 to bring the plunger over the die 15 and deposit the housing therein, contact with the bottom of the die releasing the fingers and a microswitch operating valve means to admit air to the underside of the piston 33 so that the plunger 32 is retracted. A further microswitch 55 is then closed to effect return of the plunger to its initial position, this action opening a gate to release a further housing into pick-up position. The die is then indexed to position 18 at which wires 82, Fig. 6, are fed to the holes in the housing from continuous lengths and the appropriate lengths cut off. A microswitch operated by the ram closes a single revolution clutch 70 driving a shaft bearing cams 76, 102, 106 and eccentrics 90, 96. Cam 76 actuates a microswitch 77 to operate solenoids to grip the wires in upper jaw 84 which is then moved downward to thread the wires through the holes in the housing. Cam 106 similarly operates a microswitch 105 to operate solenoids to grip the wires in the lower jaw 85 and eccentric 90 moves a shear plate 87 into engagement with the top of the housing. Cam 102 then operates the shear plate 87 to cut off the appropriate length of wire. The die is then indexed to position 19 at which the filling of glass powder is effected. The dies each pass under apertured fill plates 109, Fig. 9, hinged to a central member 110 on a rotating table, the plates 109 being brought down over the dies by rollers 111 engaging a cam track 112, pins 113 serving to locate the plates accurately relative to the dies. The assembly then passes under a roller 114 and below the opening of a hopper 115 containing powdered glass. Intermediate plates 20 are provided between the plates 109 to provide a continuous surface so that glass powder cannot flow between successive fillings. The die is then indexed to position 20 where the filling is subjected to the compression stroke of a ram, the head of which has a central depression to impart a convex form to the glass core and holes for the passage of the wire. Thereafter the die moves to position 21 where the stem is picked up by a transfer arm 149, Fig. 13, driven by a motor 147 through a one-revolution clutch 146 actuated by a microswitch 143. Vertical movement of the arm 149 for picking up and depositing the dies is controlled by a drum cam 150 and follower 151 and swinging movement by a heart-shaped cam 163 and follower 165. Revolution of the cam 150 intermittently engages a microswitch 155 to actuate an electromagnet 156 to retract a gripper plate 158 within a jaw 159 on the arm 149 so as to bring holes in the plate and jaw into register when the arm 149 is lowered over the position 21 to enable the leads on the housing to be picked up and again when the arm is swung round and lowered to deposit the housing on the fusing fixture. The conveyer 173 for the fusing fixtures is driven from a motor 195 through shafts 198, 197. Shaft 198 operates a rotating cam drive 175 producing movement for half a revolution followed by a dwell period for half a revolution whereas shaft 197 drives a worm gear 200 imparting continuous movement to the chain. Idler gears 171, 172 are provided to compensate for the changing tensions of the chain so that the fusing fixtures can be loaded and a locating cap placed over the housings after loading to maintain the leads in place during fusing, in step by step fashion, and the fixtures with the housings carried uniformly through the oven 23. The completed assemblies are finally discharged down a shoot. The shaft 198 also carries a cam 201 periodically operating the microswitch 143 controlling the clutch 146 of the transfer device. Specifications 863,022 and 926,021 are referred to.