Concentration of electric current due to an additive (particularly,
a brightener) remaining or precipitated in a high concentration at grain boundary
triple points and wiring groove portions in the surface layer of a copper plating
film is obviated, whereby precedent dissolution and/or abnormal dissolution due
to concentration of electric current is restrained, and an electropolished surface
of the copper plating film with excellent surface smoothness is obtained.
A method of producing a metallic film includes the steps of: forming a metallic
plating film (copper plating film (15)) by use of a plating solution prepared
by adding a plating additive for restraining void generation, bottom-up fill and
overfill; and electropolishing the metallic plating film by use of an electropolishing
solution prepared by adding a polishing additive capable of reacting or coupling
with the plating additive component contained or precipitated in the surface layer
of the metallic plating film.
