蓝宝石化学机械抛光液作用机制研究

Mechanism of Sapphire Chemical Mechanical Polishing by SiO_2 Particles

研究了以硅溶胶为磨料的蓝宝石化学机械抛光液在抛光过程中的作用机制。表征了抛光液在单次抛光及循环抛光前后的pH值、密度、粘度、固质量分数、zeta电位、粒径分布、金属元素浓度、大颗粒数目以及二氧化硅颗粒的形貌变化等。结合抛光前后离心液上清液的金属元素质量分数与沉淀物红外光谱图,发现在抛光过程中蓝宝石与二氧化硅颗粒表面发生固-固相反应,生成硬度较小的硅铝酸盐,促进蓝宝石表面的化学抛光。通过分析重复使用的抛光液对去除速率和表面质量的影响,进一步确认蓝宝石化学机械抛光液中氧化硅与氧化铝的固-固作用机制。

The mechanism of sapphire chemical mechanical polishing （CMP） by SiO2 particles has been investigated. The affecting parameters, including pH, density, viscosity, solids mass fraction, zeta potential, particle size distribution, the concentration of metal element, the number of large particles, and the particle morphology, etc., of the sapphire slurry in single polishing process and in cycle polishing process were discussed. The slurries before and after polishing were centrifuged to separate the solid and liquid components. Inductively coupled plasma atomic emission spectrometer（ICP-AES） was applied to determine the metal element mass fraction of the supernatant. Fourier transform infrared spectroscopy （FT-IR） was used to analyze the precipitate. The result shows that solid - solid phase reaction between sappire and the surface of the silica particles occurred and aluminosilieates with lower hardness have been generated in sapphire polishing process. This process enhances the material removal rate （MRR）. The mechanism of sapphire CMP by SiO2 particles has been further verified by MRR and surface quality in cycle polishing process.