Patent ID: 8197583

Claim:
An electroless plating solution comprising: a metal salt consisting of a water-soluble copper metal salt; a reducing agent; a chelating agent; and also a leveler composed of at least one of sulfur-based organic compounds represented by the following formulas (I) to (V): R 1 —(S) n —R 2 (I) R 1 —L 1 —(S) n —R 2 (II) R 1 —L 1 —(S) n —L 2 —R 2 (III) R 1 —(S) n —L 3 (IV) R 1 —L 1 —(S) n —L 3 (V) wherein, in the above formulas (I) to (V), n denotes an integer equal to or larger than 1, and R 1 , R 2 each independently denotes an aliphatic cyclic group or an aromatic cyclic group containing optional numbers of carbon, oxygen, phosphorus, sulfur and nitrogen atoms, provided that at least one optional substituent of at least one species may be linked to the aliphatic cyclic or aromatic cyclic group; wherein L 1 , L 2 each independently denotes one of a straight or a branched alkyl, alkyl amino, alkylene or alkoxy chain; wherein L 3 denotes one of an alkyl, alkylene, amino, alkyl amino, alkylene amino, hydroxyl, alkyl hydroxyl, alkylene hydroxyl, carboxyl, alkyl carboxyl, alkylene carboxyl, alkyl amino carboxyl, alkylene amino carboxyl, nitro, alkylnitro, nitrile, alkylnitrile, amide, alkylamide, carbonyl, alkyl carbonyl, sulfonic acid, alkylsulfonic acid, phosphonic acid, alkylphosphonic acid, sulfanyl, sulfinyl and thiocarbonyl groups.