Application of process simulation for comparison of contactless and conventional electrodeposition methods for 3D packaging

The objective of this study is to simulate the through silicon via copper filling process in conventional and recently developed contactless methods of electrodeposition for 3D packaging applications. Electrochemical measurements were employed and integrated in the development of a comprehensive process simulator. The experimental data not only provided the necessary parameters for the model but also validated the simulation accuracy. From the simulation results, the "pinch-off" effect was observed for the conventional deposition process; this effect causes partial filling and void formation. By contrast, a void-free filling with higher deposition rates was achieved by the use of the contactless technique. Further, experimental results of contactless electrodeposition on patterned wafers showed bottom-up filling in vias of 4 μm diameter and 50 μm depth without void formation and no copper overburden in the regions outside the vias.