| 摘要 |
1,225,361. Soldering. ROBERT BOSCH G.m.b.H. 23 Feb., 1968 [24 Feb., 1967; 2 Sept., 1967], No. 8788/68. Heading B3R. [Also in Divisions C7 and F2] In soldering a metal terminal to a semiconductor molten solder is applied in a reducing protective atmosphere to at least one of the bodies and the bodies are subsequently soldered together. The molten solder may be applied to a terminal in the form of a headed copper wire coated with nickel or to a metallized semiconductor body and the parts are subsequently heated together in a reducing atmosphere without the use of flux to effect their soldering. The metallizing on the semi-conductor body may be produced by applying a masking lacquer (picene or bituminous varnish) which divides the body into separate areas and electroless nickel is coated on the unmasked areas. The mask is removed and the body is coated with molten solder which adheres only to the metallized areas. In making a transistor a terminal provided with applied solder is soldered to the collector surface on one side of the semi-conductor body whilst the other side of the body having emitter and base structures is provided with applied molten solder. An apparatus for applying molten solder to headed terminal wires II comprises a vessel 14 containing 92% lead, 8% tin alloy kept molten by heating coils 15 and a centrifugal pump 18 which draws solder through a bore 19 and pumps it through a tube 20 to emerge from a nozzle 21 as a jet 10 which falls back to the solder in the vessel. A guide passage 22 through which terminal wires are fed at right-angles to the direction of the jet is mounted above the vessel 14 to extend across the vessel and is adjustable for height above the vessel by a screw-threaded ring 25. Hydrogen or hydrogen and nitrogen is fed through heating passages and then fed into the passage 22 above the vessel to flow in both directions along the passage. The terminal wires are arranged in magazines and these are fed through the passage across the jet of solder by an intermittently driven feed pawl, the wires being heated to 560‹ C. before reaching the jet to remove oxide and being cooled after leaving the jet. A liquid solder seal 33 is provided between the passage 22 and lid 24 of vessel 14, an overflow channel 35 and pipe 36 for protective gas being included and means for topping up the seal by deflecting solder from the jet. |
