| 摘要 |
PURPOSE:To improve the reliability of a projecting electrode by forming the electrode of a solder material of Pb-Sn series having higher Sn density at the center than that of the surface, thereby enhancing the bonding strength between a semiconductor element and a mounting substrate. CONSTITUTION:A primary film 5 made of 2-layer film of Cr-Cu is formed by a depositing method on a substrate 20 in which a wiring layer 2 and an electrode hole 4 are formed, with a photosensitive resin 8 as a mask Cu-plating is achieved to form an intermediate layer 6. A high melting point solder (Pb-90wt.% and Sn)-plating of Pb-Sn series is performed to form a projection 10, and a low melting point solder (Pb-10wt.%, Sn) of Pb-Sn series is plated to form a protective film 11. The unnecessary film 5 of the resin 8 is removed, the projection 10 and the film 11 are reflowed to form the projecting electrode 12 near a spherical shape. |
