GB804166A - Improvements in or relating to the manufacture of semiconductor devices - Google Patents

Abstract

804,166. Making semi-conductor devices. GENERAL ELECTRIC CO., Ltd. March 26, 1957 [March 26, 1956], No. 9423/56. Classes 83 (2) and 83 (4). In a method of making a semi-conductor device according to Specification 785,467, [Group XXXVI], wherein prior to the fusion of the electrode material on to the semi-conductor body to form the junction a surface of the electrode material is pressed on to a surface of the semi-conductor body, the electrode material is extruded in a solid state through an orifice 9, Fig. 1, into a die 11, the die is then moved to shear off cleanly the extruded material and the latter is then ejected from the die. For forming a germanium P-N-P junction transistor a pair of vertical extrusion containers 1, 2 are filled with solid indium which is extruded simultaneously through the respective orifices 9, 10 by hydraulic rams 5, 6. The extruded indium passes into horizontally slidable dies 11, 12 which are then each aligned with one of the orifices. Each die, Fig. 4, comprises an outer sleeve 13 having a hemispherical recess 22 which receives the indium. The recess is closed by the end 21 of an inner plunger 14 biased downwardly relatively to the sleeve by a spring 25. The sleeve is slidable in an aperture 26 of a slide block 28 and is biased downwardly by a spring 30; a similar slide block 32, Fig. 1, carries the upper die 12. The two slide blocks are moved horizontally in guides 37, 38 by chains 66, 58 actuated by pivoted levers and cams 62, 73, Fig. 3 (not shown), whereby the dies 11, 12 are moved from a first position alignment with the containers 1, 2 to a second position in alignment with each other as shown in Fig. 1. The slides are biased towards this second position by springs 42, 48. This movement of the dies shears off the extruded material in the recesses 22 to provide the hemispherical indium beads 93, 94, Fig. 4. In this second position a square plate of germanium 35 with newly etched surfaces has been discharged from a magazine 90, Fig. 1, on to a holder 34 and disposed between the dies 11, 12. The die 11 is then raised by a ramactuated lever 74 whereby an annular surface 86 on the sleeve 13 engages a rotating disc 87 which thus rotates the sleeve 13 and its plunger 14 and the latter is then raised further to eject the indium bead from the recess 22 and press it into engagement with the germanium plate 35. Rotation of the plunger 14 is stated to assist in producing the adhesion between the bead and the plate. The upper indium bead 94 is likewise ejected from its recess and pressed against the upper surface of the germanium plate 35 immediately after the lower bead 94. In another embodiment, Fig. 6, the indium is extruded by hydraulic rams from two aligned containers 95, 96 into apertures 107, 108, Fig. 7, in a pair of die fingers 105, 106 carried by slide members 113, 114 and pressed together by springs 121, 126. A plate of germanium 110 has been previously gripped between the fingers and against this the indium is pressed by the extrusion pressure. The fingers are then moved to a second position where the indium beads are located between pins 137, 138, Fig. 7, whilst the fingers 105, 106 are opened by pneumatic pistons 141, 142 to release the beads from the die apertures.