Dynamics of filling process of through silicon via under the ultrasonic agitation on the electroplating solution

Through-silicon-via (TSV) connection is a promising technology to provide more effective and faster data processing in integrated-circuit (IC) devices. In this study, via-filling processes with the direct ultrasonic agitation, the effects of additives (accelerator, suppressor and leveler) and different current densities are investigated. Microvias with a diameter of 20 μ m and a depth of 65 μ m is used in the electrodeposition process. The dynamic evolution of the via-filling process activated by ultrasonic under different current densities is obtained by scanning electron microscopy. It is found that the application of ultrasonic agitation can change the deposition rate of copper ion at the via and improve the filling process to obtain void-free TSVs. Under the action of ultrasonic agitation, the via-filling process under the condition of low, middle and high current density are explored to realize the "V" type filling, "U" type filling, void filling, respectively. In addition, the filling ratio and filling speed of copper in the vias under different conditions are also analyzed in this work.