| 摘要 |
PURPOSE:To enhance the bonding strength of a noble metal foil and a substrate through an adhesive sheet, by thermally diffusing a part of applied Sn in the noble metal foil and exposing the Sn-diffusion layer by etching the residual Sn to obtain a rough surface. CONSTITUTION:In a method for bonding a noble metal foil to a substrate for a printed wiring board under pressure, the surface of the noble metal foil on the press bonding side is coated with Sn and a part of Sn is thermally diffused in the noble metal foil to form a diffusion layer. Next, Sn other than in the diffusion layer is dissolved and removed using HNO3 or H2SO4 and the diffusion layer is exposed to obtain a rough surface. The noble metal foil is bonded to the substrate on the rough surface side through an adhesive layer under pressure. Since the noble metal foil is bonded to the substrate under pressure by utilizing the rough surface, adhesiveness is enhanced and bonding strength is increased. |
