Journal of the Microelectronics and Packaging Society

In this study, the effect of iron ions on the decomposition of organic additives during copper electrodeposition was examined. When either ferrous (Fe²⁺) or ferric ion (Fe³⁺) was added to the plating bath, the decompositions of co-added additives (bis-(3-sulfopropyl)-disulfide and polyethylene glycol) were clearly retarded under both electrolytic and open-circuit conditions. The retardation of additive decomposition could be attributed to the removal of reactive species (Cu⁺ and Cl₂) by redox reaction of Fe²⁺ and Fe³⁺. These results show that the Fe²⁺/Fe³⁺ redox couple could increase bath lifetime by inhibiting additive decomposition, even though it is Fenton’s reagent.

Keywords Copper, Electrodeposition, Organic additive, Decomposition, Ferric ion, Ferrous ion