| 摘要 |
1,164,591. Printed circuits. PHOTOCIRCUITS CORP. 3 Jan., 1968, No. 409/68. Heading H1R. [Also in Divisions C1, C3 and C7] Printed circuits are obtained from blanks plated by electroless deposition of metal on a substrate wherein the substrates have been rendered catalytic to such deposition by incorporating a filler comprising inert, solid finely divided particles coated with a cationic wetting agent and a Group IB or VIII metal, e.g. Pd, Au or Ag. The filler may be incorporated by mixing with the other components of the substrate, e.g.resin, prior to formation thereof, or by impregnating after formation or by coating with an ink or an adhesive including the filler, on one or both sides of the substrate. The catalytic filler may not be uniformly dispersed in or on the substrate; thus the external or internal surfaces or the sides of holes drilled through the substrate may or may not be catalytic. The substrates may be separately coated by vapour deposition or electroless deposition with a metal film or foil prior to electroless deposition according to the invention. A further electrolytic deposition may be carried out after the electroless deposition. The production of single and multi-layer printed circuit wiring boards is described including the use of resin masks and subsequent etching by spraying with or immersing in the etchant, e.g. FeCl 3 or NH 4 persulphate. A series of drawings are provided illustrating these techniques, a typical example comprising (a) initially metal coating, (b) covering with a resin mask, (c) drilling a hole through the substrate, (d) further coating those areas not covered by the mask and the sides of the hole, (e) dissolving the resin mask, and (f) etching away the initial layer of metal covered by the mask.
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