LAMINATE OF METALLIC BASE

PURPOSE:To increase the adhesion strength of the plating of a through hole by incorporating a base material in the adhesive resin layer between metallic sheets. CONSTITUTION:While each metallic sheet 2 is laminated in the state where through holes 1 coincide up and down through an adhesive resin sheet 10 in which a base member 7 is incorporated, metallic foils 12 are lapped on the other periphery of the metallic sheet 2 on the outer periphery through an adhesive resin sheet 11, and laminating adhesion is carried out by compression forming under heating. Then, the resin 4 contained in the sheets 10, 11 flows out, and the through holes 1 are filled therewith. Next, a through hole 5 is bored in the part of the resin 4, and the base material 7 is exposed to the inner peripheral surface of the through hole 5. Then, while the plating 6 of the through hole is applied onto the inner peripheral surface of the hole 5, a circuit 14 is formed by etching the metallic foil 12. Then a part of the solution for plating soaks into an adhesive resin layer 3 a little along the base material 7 from the inner periphery of the hole 5. The part 6a of the plating 6 intrudes into the adhesive resin layer 3, and the adhesion strength of the through hole- plating to the inner surface of the hole 5 is increased.