Patent GB-1229935-A (GB)
IPC: G03C1/705
Filed: 1968-09-19
Abstract: 1,229,935. Electroless deposition. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Sept.19, 1968 [Sept.22, 1967], No.44513/68. Heading C7F. [Also in Divisions G2 and H1] A method of manufacturing an electrically conductive metal pattern on an electrically insulating layer which itself serves as a support for the pattern or is adhesively secured to a substrate, comprises (i) exposing a photo-sensitive layer to light in accordance with the desired pattern so as to form a light-reaction product, (ii) treating the photo-sensitive layer prior to or after exposure to light with a solution which contains a salt of copper and/or of mercury, palladium, platinum, silver or gold so as to form an image consisting of metal nuclei, (iii) then intensifying the image optionally using a stabilized physical developer, or after formation of the nuclear metal image has been completed, using an electroless copper-or nickel- or cobalt-plating solution, wherein the photosensitive layer is self-supporting or is provided as a coating on a substrate and consists of a substantially hydropholic electrically insulating synthetic resin in which or on which finely divided solid particles of a photo-sensitive semi-conducting oxide are homogeneously distributed, wherein the photo-sensitive semi-conducting oxides forms a light-reaction product which is capable of depositing copper and/or Hg, Pd, Pt, Ag or Au from the solution containing the salt of copper and/or of Hg, Pd, Pt, Ag or Au, wherein the concentration of the salt in the salt-containing solution is adjusted to a value within a range in which metal nuclei of the relevant metal are deposited, and wherein if necessary the metal salt present in the areas of the layer outside the nuclear image are removed before intensification of the image with the electroless plating solution. The photo-sensitive semi-conducting oxide is preferably TiO 2  or ZnO. The exposed photosensitive layer is preferably directly treated with a stabilized physical silver developer. Prior to exposure to light the photo-sensitive layer may be treated in various ways:- (a) with a solution containing at least 0À001% by weight of a silver salt, wherein the image of silver nuclei formed an exposure to light is intensified with the aid of an electroless copper-plating solution after the silver salt present on the areas outside the image of silver nuclei has been removed. (b) with a solution containing an aurous compound, wherein the image of gold nuclei formed on exposure to light is intensified with the aid of an electroless copper, nickel or cobalt-plating solution after the aurous compound present on the areas outside the image of gold nuclei has been removed, (c) with a solution containing Pd<SP>++</SP> or Pt<SP>++ </SP>ions in a concentration which as a function of the metal compound used is from 0À0005 to 0À1% by weight, wherein the image of Pd or Pt nuclei formed on exposure to light is intensified with an electroless copper, nickel or cobalt-plating solution without any preliminary treatment; or (d) with a solution containing cupric ions in a concentration from 0À005% to 2À5% by weight of a cupric compound, wherein the image of copper nuclei formed on exposure to light is intensified with an electroless copper-plating solution after activation, with an electroless nickel-plating solution.