IMMERSION TIN OR TIN ALLOY PLATING BATH WITH IMPROVED REMOVAL OF CUPROUS IONS

摘要

The invention concerns an immersion tin plating bath which comprises at least one aromatic sulfonic acid, at least one first precipitation additive and at least one second precipitation additive. The at least one first precipitation additive is an aliphatic poly-alcohol compound, an ether thereof or a polymer derived thereof having an average molecular weight in the range of 62 g/mol and 600 g/mol. The at least one second precipitation additive is a polyalkylene glycol compound having an average molecular weight in the range of 750 to 10,000 g/mol.