Roughening solution for rolled copper foil and method for producing roughened copper foil

An aqueous composition for roughening a surface of a rolled copper foil, the aqueous composition comprising:

• hydrogen peroxide (A);
• sulfuric acid (B);
• and
• an azole compound (C) and/or a salt thereof, wherein
• a content of hydrogen peroxide (A) in the aqueous composition is 0.1 to 5% by mass based on a total mass of the aqueous composition,
• a content of sulfuric acid (B) in the aqueous composition is 0.5 to 15% by mass based on the total mass of the aqueous composition,
• a content of the azole compound (C) and/or the salt thereof in the aqueous composition is 0.01 to 0.3% by mass based on the total mass of the aqueous composition,
• a molar ratio between hydrogen peroxide (A) and sulfuric acid (B) in the aqueous composition is in a range of 0.1 to 1.0 expressed by a ratio of hydrogen peroxide/sulfuric acid, and
• the azole compound (C) is at least one selected from the group consisting of a benzotriazole compound and a tetrazole compound,
• wherein said aqueous composition is free of chloride ion.