Abstract: In wiring circuit board having fine and isolated conductor circuit pattern, a metal deposit coat is formed at desired position on the isolated conductor circuit pattern without damaging conductor circuit of the pattern, as an object of the invention. An electrically conducting layer consisting of a material electrically conducting and peelable with one of heat, solvent and alkali is formed on the wiring circuit board so as to be at least in contact with the isolated conductor circuit pattern on which the deposit coat is to be formed, a peelable protect layer is formed to be superposed on the electrically conducting layer at least at other portions than the portion where the deposit coat is to be formed, a metal deposition is performed on the portion not coated with the protect layer by means of an electroplating with the electrically conducting layer used as a power supply layer, and the electrically conducting and protect layers left on the wiring circuit board are peeled off.

Abstract: An undercoat containing copper and bismuth and/or vanadium is formed on a ceramic substrate such as Al.sub.2 O.sub.3. When the undercoat contains copper and bismuth, the ceramic substrate having the undercoat is heated at a temperature between 600.degree. C. and 1100.degree. C. in an oxidative atmosphere to obtain a fired undercoat on the ceramic substrate. The fired undercoat is formed with copper oxide particles and a binder phase containing bismuth and copper for bonding between adjacent copper oxide particles. A bismuth content in the fired undercoat is determined within a range of 10 to 90 wt %. When the undercoat contains copper and vanadium, the ceramic substrate having the undercoat is heated at a temperature between 450.degree. C. and 1100.degree. C. in the oxidative atmosphere to obtain a fired undercoat which is formed with copper oxide particles and a binder phase containing vanadium and copper. A vanadium content in the fired undercoat is determined within a range of 3 to 63 wt %.

Abstract: A method for roughening a ceramic substrate surface includes a step of sequentially taking out part of roughening a treatment bath of phosphoric acid into which the ceramic substrate is dipped prior to a formation on the substrate of conductor a layer, and subjecting the part of the bath taken out sequentially to regeneration treatment. Any increase in the viscosity due to dehydrating condensation of the roughening bath can be thereby effectively restrained to prolong effective life of the bath. Further, the surface roughened ceramic substrate can be provided thereon with conductor layers smoothly formed by means of a plating and eventually with a circuit pattern as well as a resistor formed on the pattern within an inert gas atmosphere.