Plated product having copper thin film formed thereon by electroless plating

A plated product comprising a substrate having formed thereon an alloy barrier thin film for preventing copper diffusion comprising metal B, which has barrier properties in relation to copper and enables displacement plating with the copper ions contained in an electroless copper plating solution, and metal A, which tends to have less ionization than metal B in an electroless copper plating solution at a pH of 10 or higher;

• the alloy barrier thin film for preventing copper diffusion has a composition wherein metal A constitutes between 15 and 35 at % of atoms contained in the alloy barrier thin film;
• wherein metal B is tungsten or molybdenum and metal A is at least one metal selected from a group consisting of nickel, cobalt and tin;
• wherein the alloy barrier thin film consists of metal A and metal B;
• and a copper thin film is formed on the alloy barrier thin film by electroless plating using an electroless copper plating solution at a pH of 10 or higher, wherein the copper thin film formed by electroless plating has a thickness of no more than 10 nm and a resistivity of no more than 10 μΩ·cm.