Organic additives are typically used in the pulse electrodeposition of copper (Cu) to prevent void formation during the filling of high aspect ratio features. In this work, the role of bath chemistry as modified by organic additives was investigated for its effects on Cu trench microstructure. Polyethylene glycol (PEG), bis(3-sulfopropyl) disulfide (SPS), and Janus green b (JGB) concentrations were varied in the Cu electrodeposition bath. Results indicated a correlation between the JGB/SPS ratio and the surface roughness and residual stresses in the Cu. Electron backscattering diffraction (EBSD) and transmission Kikuchi diffraction (TKD) were used to study the cross-sectional microstructure in the trenches. Finer grain morphologies appeared in trenches filled with organic additives as compared to additive-free structures. Cu trench (111) texture also decreased with increasing organic additive concentrations due to more pronounced influence of sidewall seed layers on trench features. Twin density in the microstructure closely tracked calculated stresses in the Cu trenches. A comprehensive microstructural analysis was conducted in this study, on an area of focus that has garnered little attention from the literature, yet can have a major impact on microelectronic reliability.

中文翻译：

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有机添加剂对铜沟槽显微结构的影响

有机添加剂通常用于铜 (Cu) 的脉冲电沉积，以防止在填充高纵横比特征期间形成空隙。在这项工作中，研究了有机添加剂改性的镀液化学作用对 Cu 沟槽微观结构的影响。聚乙二醇 (PEG)、双 (3-磺丙基) 二硫化物 (SPS) 和 Janus green b (JGB) 浓度在 Cu 电沉积浴中发生变化。结果表明 JGB/SPS 比率与 Cu 的表面粗糙度和残余应力之间存在相关性。电子背散射衍射 (EBSD) 和透射菊池衍射 (TKD) 用于研究沟槽中的横截面微观结构。与无添加剂结构相比，在填充有机添加剂的沟槽中出现了更细的晶粒形态。由于侧壁种子层对沟槽特征的影响更显着，Cu 沟槽 (111) 纹理也随着有机添加剂浓度的增加而减少。微观结构中的孪生密度密切跟踪铜沟槽中的计算应力。在这项研究中进行了全面的微观结构分析，重点关注的领域很少受到文献的关注，但可能对微电子可靠性产生重大影响。