Abstract: A method for forming a circuit pattern includes at least a step (a) of subjecting a non-conductor to electroless copper plating to form a copper film and a step (b) of etching the copper film so as to form a circuit pattern. As a catalyst for the electroless copper plating, a silver colloidal solution is used containing as essential components at least the following: (I) silver colloidal particles; (II) one or more of ions of metal having an electric potential which can reduce silver ions to metal silver in the solution and/or ions which result from oxidation of the ion at the time of reduction of the silver ions; and (III) one or more of hydroxycarboxylate, condensed phosphate and/or amine carboxylate ions. The silver colloidal particles (I) are produced by the ion (II) of the metal having an electric potential which can reduce silver ions to metal silver. The circuit pattern may be formed on a printed wiring board.

Abstract: A method for forming a circuit pattern includes at least a step (a) of subjecting a non-conductor to electroless copper plating to form a copper film and a step (b) of etching the copper film so as to form a circuit pattern. As a catalyst for the electroless copper plating, a silver colloidal solution is used containing as essential components at least the following: (I) silver colloidal particles; (II) one or more of ions of metal having an electric potential which can reduce silver ions to metal silver in the solution and/or ions which result from oxidation of the ion at the time of reduction of the silver ions; and (III) one or more of hydroxycarboxylate, condensed phosphate and/or amine carboxylate ions. The silver colloidal particles (I) are produced by the ion (II) of the metal having an electric potential which can reduce silver ions to metal silver. The circuit pattern may be formed on a printed wiring board.