Effect of Pretreatment on Copper Filling of High Aspect Ratio Through-Silicon Via (TSV)

Ultrasound and vacuum pretreatment with pure water as prewetting solution could achieve good wetting effect, not only improving the filling quality but filling rate as well. In this paper, we studied the effects of pretreatment with SPS(Na₂(SO₃(CH₂)₃S)₂)) as prewetting solution on the filling processes in three commercial bath systems. By means of LSV and EIS, we analyzed the functional mechanism of the SPS in the pretreatment. According to the electrochemical test results, electroplating experiments were further carried out under different current densities to analyze the filling process and finally put forward a feasible proposal to optimize the proportion of additives and the electric parameters used in the void-free electro deposition.