Electroless copper plating solution

An electroless copper plating solution, which comprises at least one of the water-soluble copper salts selected from the group consisting of sulfate, nitrate, acetate, formate, carbonate, and hydroxide of copper, at least one of the complexing agents for cupric ions selected from the group consisting of ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminetriacetic acid, diethylenetriaminepentaacetic acid, nitriloacetic acid, iminodiacetic acid, cyclohexylenediaminetetraacetic acid, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene diamine, citric acid and tartartic acid;

• at least one of the reducing agents selected from the group consisting of formaldehyde, paraformaldehyde, glyoxal, and trioxane, and alkali metal hypophosphites;
• at least one of the pH-controlling agents selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and ammonium hydroxide, in an amount necessary to make the pH of the plating solution 11-13.5;
• at least one of stabilizers selected from the group consisting of compounds represented by the following general formulae (1)-(4):
• ##STR32## wherein m and n are integers of 1-100, R an alkyl group having 1 to 3 carbon atoms, and R' an alkylene group of --CH.sub.2 --, --(CH.sub.2).sub.2 --, or --(CH.sub.2).sub.3 --in an amount of 1.times.10.sup.-6 -1.times.10.sup.-4 mole/l, and water in an amount to dissolve the foregoing compounds and make the solution 1 l.

In an electroless copper plating solution containing water, a water-soluble copper salt, a reducing agent, and a pH-controlling agent, the improvement wherein said plating solution also contains at least one of the stabilizers selected from the group consisting of compounds represented by the following general formulae (1)-(4):

• ##STR34## wherein m and n are integers of 1-100, R an alkyl group having 1 to 3 carbon atoms, and R' an alkylene group of --CH.sub.2 --, --(CH.sub.2).sub.2 -- or --(CH.sub.2).sub.3 --;
• at least one of complexing agents for cupric ions selected from compounds represented by the following general formulae (5) and (6):
• ##STR35## wherein a, b, c and d are integers of 1, 2 or 3, n is 2 or 3, and X a hydrogen atom or an alkali metal;
• and at least one of complexing agents for cuprous ions selected from the group consisting of the compounds represented by the following general formulae (7)-(9):
• ##STR36## wherein X is --N--;
• X' is --NH--, --CH.sub.2 --;
• R, R' is --(CH.sub.2).sub.2 --;
• --(CH.sub.2).sub.3 --, --CH.dbd.CH--, --CH.dbd.CH--CH.sub.2 --, --N.dbd.N--, --N.dbd.N--CH.sub.2 -- and ##STR37## and R" is a fatty acid residue.