关键词: 抑制剂, 电镀铜, 微观组织, 杂质, 电学性能

Abstract: This study investigated three nonionic inhibitors with the same molecular weight but different molecular structures: linear polyethylene glycol (PEG), an aromatic sterically hindered inhibitor (NP-40), and an ethylene oxide-propylene oxide block copolymer (EO-PO). Electrochemical analysis showed that although the polarization behavior of each component was similar without the addition of SPS, significant differences in polarization behavior occurred under the condition of co-addition of SPS. The CV curves showed that the polarization ability was: NP-40 > EO-PO > PEG. Further microstructure characterization, impurity testing, and electrical performance testing were performed on the copper coatings prepared under the coexistence of inhibitors and SPS. EO-PO sample exhibited a relatively small grain size (1.7 μm) and a high resistivity and elevated impurity content. After annealing at 150°C, a remarkable grain growth was observed in this system, which can be attributed to the high grain growth driving force inherent in the fine-grained microstructure. The intensity of this driving force far exceeded the grain boundary pinning effect of impurity elements, thus masking the pinning effect of impurities.Notably, however, impurity elements remained a significant and non-negligible controlling factor in resistivity evolution. In contrast, NP-40 sample not only demonstrated the optimal inhibition capacity but also maintained a relatively low electrical resistivity and minimal impurity residue. These findings provide a theoretical basis for the rational design of inhibitors for advanced copper interconnect electrodeposition, thereby improving the electrical properties of copper plating.

Key words: inhibitors, copper plating, microstructure, impurities, electrical properties