Disclosed herein is a composition including copper ions and at least one additive including a polyalkyleneimine backbone including N-hydrogen atoms, where (a) the polyalkyleneimine backbone has a mass average molecular weight MW of from 600 g/mol to 100 000 g/mol, (b) the N-hydrogen atoms are each substituted by a polyoxyalkylene group including an oxyethylene and a C3 to C6 oxyalkylene unit, and (c) the average number of oxyalkylene units in the polyoxyalkylene groups is of from more than 10 to less than 30 per N-hydrogen atom in the polyalkyleneimine.