PURPOSE: To eliminate such a possibility as a halo phenomenon is generated and to increase the adhesion of a copper circuit with a resin by a method wherein an electrolytic copper plating is applied to the copper circuit provided on a circuit board for internal layer and a node is formed on the surface of the copper circuit and the surface is roughened.

CONSTITUTION: An electrolytic copper plating is set in such a way that an acid copper plating bath, for example, is used to make a current flow using a circuit of a circuit board for internal layer use as a cathode and the height of a node, which protrudes from the surface of the circuit, becomes 2 to 3 microns. If the height of the node is less than 2 microns, the effect of the improvement of adhesion by surface roughening is insufficient and if the height of the node is a size exceeding 3 microns, there is a possibility of generating pinholes and the height is not desirable. The adhesion between the copper circuit and a resin can be increased by the action of a roughened surface which is formed with the node and moreover, as the roughened surface of the copper circuit is formed with the node by the electrolytic copper plating, there is no possibility that a copper oxide is dissolved in an acid in a plating process or the like and a halo phenomenon is generated like the case where an oxidation treatment is performed to roughen the surface of the circuit.