| 摘要 |
PURPOSE:To firmly bond a solder bump, a Cu wiring and an Ni wiring to one another by coating a thin film composed of Au, Ag, Pt, Pd, Pb, Sn, In, Pb-Sn and Pb-In on a portion on which a bump is expected to be formed on the Cu wiring or the Ni wiring in advance. CONSTITUTION:A protecting film 5 composed of such as insulating material as polyimide is coated on a Cu wiring 2 formed on a printed circuit board 1 as a portion on which a semiconductor chip 4 is mounted is left. A thin film 6 is coated on a portion on which a solder bump 3 is expected to be formed, namely, a portion for mounting the semiconductor chip 4 thereon by, for example, an electroless Sn plating. Then, the solder bump 3 composed of, for example, Pb-Sn is formed on the thin film 6, the end portion of the solder bump 3 cut from a solder wire is spheroidized in a reflow furnace or the like and the semiconductor chip 4 is mounted. Therefor, the thin film 6 intervening between the solder bump 3 and the Cu wiring 2 reinforces a bonding strength between the solder bump 3 and the Cu wiring 2. Thus, the solder bump 3 and the Cu wiring 2 can firmly be bonded to each other. |
