Electroless plating process

An electroless plating process for sequentially forming a nickel film and a gold film on a surface of a copper material by an electroless plating method, comprising:

• forming the nickel film directly on the surface of the copper material by an electroless strike plating method;
• and
• forming the gold film by a reduction-type electroless plating method;
• wherein the electroless strike plating method does not include use of a treatment with a palladium catalyst, and is performed by
• immersing the copper material in an electroless nickel strike plating solution that
• contains nickel sulfate hexahydrate in a concentration of 0.002 to 1 g/L in terms of nickel, one or more complexing agents selected from the group consisting of malic acid, glycine, acetic acid, and malonic acid, and one or more reducing agents selected from the group of dimethylamine borane, trimethylamine borane, and hydrazine, but does not contain boric acid, wherein the complexing agent is in a concentration of 0.5 to 5 g/L and the reducing agent is in a concentration of 2 to 10 g/L, and
• has a pH adjusted to 6 to 10 and a bath temperature adjusted to 20 to 55° C.;
• wherein the nickel film has a uniform film thickness of 0.005 to 0.3 μm.