It is significantly important to develop novel suppressor to achieve cobalt superconformal filling. Linear sweeping voltammetry (LSV) and impedance spectra (EIS) were coupled together to study the effect of novel dye suppressor nitrotetrazolium blue chloride (NBT) on cobalt electrodeposition. The adsorption behavior of NBT on cobalt substrate was investigated by applying density functional theory (DFT) calculation, molecular dynamics (MD) simulation and in situ Raman spectra , while the interaction between NBT and cobalt ions (Co 2+ ) is analyzed based on topology analysis and interaction region indicator (IRI) analysis. Synergistic suppressing mechanism, namely adsorption effect and coordination effect, was proposed to explain the suppressing effect of NBT during cobalt electrodeposition. The cobalt surface morphology analysis under the influence of NBT demonstrates that NBT is of grain refinement, while XRD analysis indicates that the formation of Co hcp (100) is formed preferentially. The superconformal filling of cobalt is achieved in microvias with different diameters. The cobalt layer is of excellent quality due to low surface deposit thickness (SDT). The SDT values are 15.9 μm, 8.8 μm and 4.9 μm for 150 μm, 100 μm and 50 μm.
Yaqiang Li,Xiaochuan Ma,Ruopeng Li,Jinqiu Zhang,Peixia Yang,Anmin Liu,Bo Wang,Peter Broekmann,Maozhong An
Achieving cobalt superconformal (bottom-up) growth is significantly important. Electrochemical methods, including cyclic voltammetry, electrochemical impedance spectra and EQCM-derived Coulomb-voltage curves, were used to confirm the suppressing influence of new suppressor Nitrotetrazolium Blue chloride (NBT). In situ Raman spectroscopy was used confirm that NBT can effectively adsorb on cobalt surface. Besides, EQCM-derived Coulomb-voltage illustrates that it is more beneficial for cobalt electrodeposition at high pH. The NBT effect on hydrogen evolution reaction (HER) was studied by LSV and chronoamperometry. Finite element simulation is used to investigate the accelerating effect of NBT on HER and convection. Suppressing-accelerating effect is proposed to illustrate effect of NBT. NBT can not only suppress the cobalt deposition but also can accelerate local convection by intensifying HER, which can in turn strengthen NBT adsorption. SEM analysis demonstrates that convection and NBT can refine grain. High-quality cobalt is achieved with low SDT values ranging from 24 μm to 45 μm and high FP values (75.4 % for 150 μm, 88.9 % for 100 μm and 87.2 % for 50 μm).
危险品化学品经营许可证（带存储）