纯铅化学机械抛光中工艺参数对抛光性能的影响

为获得高质量纯铅表面，采用化学机械抛光(CMP)的方法并辅以自制抛光液，研究了胶体二氧化硅抛光颗粒的形状、粒径和浓度、加载压力、抛光头与抛光盘转向和转速、抛光液流量等工艺参数对铅片表面材料去除率和粗糙度的影响. 研究表明：小粒径异形(眉形)胶体二氧化硅抛光颗粒相较于大粒径球形颗粒更有利于铅片抛光，抛光颗粒的粒径和浓度对纯铅抛光性能的影响主要取决于铅片表面与胶体二氧化硅颗粒以及抛光垫表面丝绒的耦合作用关系. 随着加载压力、抛光头与抛光盘转向和转速、抛光液流量的改变，铅片表面和抛光垫之间驻留的层间抛光液的厚度以及状态发生改变，从而直接影响抛光液的流动性、润滑性和分散性，以及影响抛光颗粒和化学试剂与铅片表面的机械化学作用，进而影响抛光质量和材料去除率. 通过对工艺参数影响的研究和对工艺参数的优化，最终获得了表面粗糙度Ra为1.5 nm的较为理想的超光滑纯铅表面，同时材料去除率能够达到适中的380 Å/min.

To obtain high-quality pure lead surfaces, Chemical Mechanical Polishing (CMP) assisted with a self-prepared polishing slurry was adopted. The effects of process parameters including the shape, particle size and concentration of colloidal silica polishing particles, applied pressure, rotational directions and speeds of the polishing head and platen, and polishing slurry flow rate on the material removal rate (MRR) and surface roughness of lead wafers were investigated. The results show that small-sized eyebrow-shaped colloidal silica polishing particles are more conducive to lead wafer polishing compared to large-sized spherical particles. The influence of the particle size and concentration of polishing particles on the polishing performance of pure lead mainly depends on the coupling interaction among the lead wafer surface, colloidal silica particles and the velvet layer of the polishing pad. As the applied pressure, rotational directions and speeds of the polishing head and platen, and polishing slurry flow rate vary, the thickness and state of the inter-slurry layer residing between the lead wafer surface and the polishing pad will change, which directly affects the fluidity, lubricity and dispersibility of the polishing slurry, as well as the mechanochemical interactions between polishing particles, chemical reagents and the lead wafer surface, thereby influencing the polishing quality and material removal rate. Through the investigation of process parameter effects and parameter optimization, an ideal ultra-smooth pure lead surface with a surface roughness Ra of 1.5 nm was finally achieved, while the material removal rate reached a moderate level of 380 Å/min.