碲锌镉晶体化学机械抛光液的研究

Research on Chemical-mechanical Polishing Slurry for CdZnTe Crystal

本文以硅溶胶为磨料颗粒、次氯酸钠(NaClO)为氧化剂制备适用于CZT晶片的化学机械抛光液。采用XPS能谱分析CZT表面元素化学态,研究CZT化学机械抛光过程中抛光液的化学作用机理,使用激光干涉仪、原子力显微镜研究抛光液中NaClO含量对晶片抛光速率、晶片表面PV值及表面粗糙度Ra的影响。结果表明,硅溶胶-次氯酸钠抛光液通过与CZT晶体中Te单质或CdTe发生化学反应,生成TeO_2。随后在一定压力下,抛光盘与CZT晶片发生相对运动,并在硅溶胶磨料颗粒的辅助作用下去除反应物。当NaClO含量在2%~10%时,随着NaClO含量的增加,晶片表面PV值和粗糙度Ra值先降低后升高,去除速率则随着NaClO含量的增加而增加。NaClO含量为6%时,PV值和Ra值最低,得到的晶片表面质量最好。

In this paper, silica solution and NaClO were chosen as raw materials to prepare chemical-mechanical polishing slurry for CdZnTe crystal. The mechanism of chemical-mechanical polishing slurry to CZT was researched by analyzing the elemental state of the CZT surface with X-ray Photoelectron Spectrometer （XPS）. Laser Interferometer and Atomic Force Microscope （AFM） were used to investigate the effect of NaClO content on polishing rate, surface flatness and roughness. The results show that the chemical-mechanical polishing slurry mainly reacts with Te or CdTe, and TeO2 is obtained. Then at a certain pressure, there is relative motion between polishing discs and CZT wafer, and the reaction film is removed under a supporting role of SiO2 particles, which make the surface become smooth. When the NaClO content ranges from 2% to 10%, with the increase of NaClO, the PV value and roughness of CZT surface decrease at first and then increase, while the polishing rate increases all the time. When the NaClO content is 6%, the PV value and roughness reach the minimum, and the polishing surface of CdZnTe with high quality is obtained.