| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed circuit board suitable for lead-free solder bonding processing by improving the characteristics of a metal pad surface of a circuit board, in which a number of metal pads for connecting circuit elements to desired portions of a conductor circuit pattern to configure an electronic circuit are formed, and to provide a method of manufacturing the printed circuit board.SOLUTION: In the printed circuit board for lead-free solder which includes a required number of conductor wiring patterns each stuck to the surface of an insulating substrate and having a desired shape and a plurality of electrode pads formed on desired portions of the conductor wiring patterns, a first nickel-phosphorous plating layer 2 stuck to the surface of the electrode pad and having a middle phosphorous concentration is formed, and then a second nickel-phosphorous plating layer 3 stuck to the surface of the first nickel-phosphorous plating layer 2 and having a low phosphorous concentration is formed to form a two-layer nickel-phosphorous plating layer composed of the first and second nickel-phosphorous plating layers and having middle and low phosphorous concentrations respectively. |
