Electro copper plating bath and electro copper plating method

SOLUTION: A water-soluble copper salt, sulfuric acid, chloride ion, brightener, carrier and leveler, wherein the leveler is represented by the following formula (1) or a quaternized compound represented by the following formula (2): Copolymer An electrolytic copper plating bath which is one or both of the above and an electrolytic copper plating method for via-fill plating a via hole formed on the substrate using the same. [Effect] A via hole having a small diameter and a high aspect ratio can be filled without generating a void, and is suitable for plating a via hole / through hole mixed substrate. [Selection figure] None