Silicon dioxide (SiO2) solid blocking layer on through-glass via surface for efficient highly selective copper filling

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Cu electrodeposition is utilized for filling through-glass via (TGV) to achieve the purpose of interconnection. However, Cu deposition is not only within the through-hole of TGV but also on the top and bottom surfaces of the through-hole. Therefore, additional chemical-mechanical-planarization (CMP) processes are required to remove the Cu overburden. To reduce the burden of CMP, this study proposes a method of making a SiO2 blocking layer (SBL) on the seed layers at the top and bottom of TGV before the filling process to inhibit excess Cu overburden deposition on the TGV surfaces during the filling process. We validated the effectiveness of the SBL through optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical measures. The Cu overburden typically requires removal through CMP processes after the Cu wiring. This study helps reduce the additional costs incurred during the TGV production process. The experimental results indicate that the proposed method is feasible, offering a new perspective for research on the selective filling of TGV.