Investigation of a Single-Component Additive for Bottom-Up Superfilling of the High-Aspect-Ratio TSV by Theoretical and Experimental Studies

Tetronic 701 (TE 701) as a high-performance single-component additive is used for obtaining bottom-up Cu superfilling of the through-silicon via (TSV). However, the filling mechanism and the relationship between its molecular structure and performance remain unclear. In this work, the characteristics of TE 701, distinguished from the traditional suppressor PEG 4000, are systematically investigated through electrochemical measurements, theoretical calculations, and electroplating filling experiments. Electrochemical analysis reveals TE 701's superior suppression performance, with convective-dependent adsorption behavior in methanesulfonic acid–based electrolytes, a notable difference from PEG 4000. Quantum chemical calculations show that TE 701 has a smaller energy gap (5.618 eV) compared to PEG 4000 (6.239 eV), implying a stronger inhibition of Cu deposition. The central ethylenediamine core and the methyl groups on the side chains of TE 701 are key structural elements that contribute to its superior electroplating performance. Filling experiments have demonstrated a perfect bottom-up superfilling in 5 μm × 50 μm TSV using TE 701 under galvanostatic plating. This process is characterized by an ultrafast filling speed, completing in just 10 min at a current density of 0.1 ASD. This work highlights the potential of TE 701 as a single-component suppressor for small-sized, high-aspect-ratio TSV and offers crucial molecular insights for developing new single-component suppressors to enable bottom-up superfilling in TSV.