Patent GB-1194894-A (GB)
Title: Improvements in and relating to methods of manufacturing carriers for electrical circuit elements
IPC: H01R12/55
Filed: 1967-06-20
Abstract: 1,194,894. Printed circuit assemblies; semiconductor devices. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 20 June, 1967 [23 June, 1966], No. 28323/67. Headings H1K and H1R. In the manufacture of a carrier for semiconductor devices and passive elements printed supply conductors are firmly adhered to one part of the carrier and not so firmly adhered to a contiguous part of the carrier, which contiguous part is then removed so that the less adhering parts of the conductors disengage from the carrier as projecting supply conductors. In a first embodiment a glass or ceramic plate is first coated by vapour deposition through a mask with aluminium chromium over an area corresponding to connections to the electrodes of a semi-conductor device which coating rigidly adheres to the plate. A copper layer, is then deposited over the whole of the carrier and photoetched to provide the arrangement of Fig. 2 in which cross hatching indicates the superposed layers and hatching the single copper layer. The hatched supply conductors between lines C, D are now electrolytically reinforced by copper, connecting conductor 5 acting as an electrode. After this step the carrier and conductors are detached below the line D. A microtransistor 6, Fig. 4 is then soldered to the conductors 2, 3, 4 by electrodes 7 and after scratching of the carrier along line F the transistors and connectors are encapsulated. The carrier plate below line F is then broken away leaving the supply conductors projecting from the encapsulated part, Fig. 5 (not shown), and finally the individual transistors are separated by breaking along the vertical lines A, G &c. In the embodiment of Fig. 6 part of ths carrier which is to be removed from the part to be retained forms the part to be retained for the two adjacent carriers. The aluminium chromium layer is first deposited as in the first embodiment and a copper layer deposited thereover. A mask is then positioned over the copper and the carrier immersed in an electrolytic bath electrical connection being made to the copper layer. Only the unmasked portions of the copper are electroplated after which the copper layer not covered by the electrolytically deposited copper is removed in an etching bath. The supply leads may be obtained from a copper sheet applied to the aluminium chromium layer. Alternatively the electrolytically deposited copper may be deposited over the whole area and superfluous parts removed by etching. The carrier is then broken along the chain lines to separate the transistors and also supply conductors from adjacent carriers. In a third embodiment Fig. 7b and Fig. 7a (not shown), a nickel chromium alloy is vapour deposited over the whole of the common carrier which well adheres to the glass carrier and then a nickel layer is deposited thereover. After masking the nickel the uncovered parts of the nickel and alloy are removed by etching to leave the strips. A resistor 12 is then formed by etching through a second mask to remove the uncovered nickel. The resulting pattern corresponds to the alu-. minium layer of the previous embodiments and the supply conductors are formed as before by applying a coating of copper over the substrate and reinforcing and defining the conductors as described with reference to Fig. 6.