Copper-clad laminated board, and circuit board for printed wiring board and method for producing the same

A method for producing a circuit board for a printed wiring board, comprising an insulative substrate having a conductive circuit formed on one side thereof and viaholes formed in through-holes extending from the other side of the insulative substrate to the conductive circuit and in which there is formed between the one side of the insulative substrate and the conductive circuit a metal layer whose melting point is lower than that of zinc, the method comprising at least the following:

• (a) roughening one side of a copper foil and then forming, on the roughened surface, a metal layer whose melting point is lower than that of the roughened surface of the copper foil;
• (b) laminating the copper foil at the side thereof on which the metal layer is formed to one side of the insulative substrate;
• (c) etching the copper foil attached to the insulative substrate to form the conductive circuit;
• (d) forming through-holes extending from the other side of the insulative substrate to the conductive circuit by lasing and then forming filled-viaholes in the through-hole.

A method for producing a circuit board for a printed wiring board, including insulative substrate having a conductive circuit formed on one side thereof and viaholes formed in through-holes extending from the other side of the insulative substrate to the conductive circuit and in which there is formed between the one side of the insulative substrate and the conductive circuit a metal layer whole melting point is lower than that of zinc, the method comprising at least the following:

• (a) forming a low melting point metal layer on one side of the insulative substrate by the PVD or CVD method or electroless plating;
• (b) making an electrolytic copper plating to the insulative substrate having the low melting point metal layer formed thereon to provide a conductive circuit having a copper plated layer formed the low melting point metal layer;
• (c) etching the conductive layer to the conductive circuit on one side of the insulative substrate;
• and
• (d) forming through-holes extending from the other side of the insulative substrate to the conductive circuit by lasing and then forming filled-viaholes in the through-hole.