Dilute H2SO4 solution for copper seed cleaning in electroplating

The effects of surface cleaning to eliminate the surface oxides formed on Cu seed layer with dilute H2SO4 solution were investigated. Cu seed layer formed on Ti/Si(100) wafer by sputter deposition was exposed to air to grow native Cu oxide. Dilute H2SO4 solutions and/or TS-40A alkaline soak cleaner were used to remove the native Cu-oxide. After mainly carbon groups (such as C═O) on surface of Cu seed layer were removed by pretreatment of TS-40A alkaline solution, subsequently, dilute H2SO4 acid solution removed Cu-oxides (Cu2O and CuO) as well as a lot of O═C and Cu(OH)2.