Patent ID: 6949412

Claim:
A method for manufacturing an interposer-forming clad layer for use in a semiconductor device manufactured by press-bonding an oxygen-free copper foil material and a nickel foil material at a rolling reduction of 0.1 to 3%, wherein the interposer-forming clad plate for use in the semiconductor device is formed by previously applying an activating treatment to the bonded surfaces of an oxygen free copper foil and the nickel foil or nickel plating in a vacuum vessel and then laminating an oxygen free copper foil and the nickel foil material or nickel plating and cold press-binding them at a rolling reduction of 0.1 to 3% in which the activating treatment is applied in an inert gas atmosphere at an extremely low pressure of 1×10 1 to 1×10 −2 Pa, using the nickel plated oxygen free copper foil material and an oxygen free copper foil material as one electrode A having a bonding surface grounded to the earth, respectively, and conducting glow discharge by applying an AC current at 1 to 50 MHz between the electrode A and another electrode B supported insulatively and applying sputter etching, with the area of the electrode exposed in plasma caused by the glow discharge being ⅓ or less of electrode B.