Patent ID: 7624502

Claim:
A method of manufacturing a circuit-forming board, comprising: providing a metal foil having a first surface and a second surface opposite to the first surface, the metal foil including a pressure absorption portion and a hard portion adjacent to the pressure absorption portion, the pressure absorption portion being provided at the first surface, the pressure absorption portion having a thickness that changes according to a pressure applied thereto; providing a material sheet having a surface, the surface having a hole formed therein; forming a conductive portion in the hole of the material sheet such that the conductive portion protrudes from the material sheet; providing a laminated sheet by placing the metal foil on the surface of the material sheet such that the second surface of the metal foil faces the material sheet, such that the conductive portion contacts a first portion of the second surface of the metal foil opposite to the pressure absorption portion, and such that the material sheet contacts a second portion of the second surface of the metal foil opposite to the pressure absorption portion; heating and pressing the laminated sheet to harden the material sheet; and crushing first and second portions of the pressure absorption portion of the metal foil, the first and second portions of the pressure absorption portion being opposite to the first and second portion of the second surface of the metal foil, respectively, during said heating and pressing of the laminated sheet such that a thickness of the first portion of the pressure absorption portion is smaller than a thickness of the second portion of the pressure absorption portion.