• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2018, Vol. 54 ›› Issue (19): 224-231.doi: 10.3901/JME.2018.19.224

• 制造工艺与装备 • 上一篇    下一篇

不同氧化剂对6H-SiC化学机械抛光的影响

倪自丰1, 陈国美1,2, 徐来军1, 白亚雯1, 李庆忠1, 赵永武1   

  1. 1. 江南大学机械工程学院 无锡 214122;
    2. 无锡商业职业技术学院机电技术学院 无锡 214153
  • 收稿日期:2017-10-11 修回日期:2018-05-09 出版日期:2018-10-05 发布日期:2018-10-05
  • 通讯作者: 倪自丰(通信作者),男,1981年出生,博士,副教授。主要研究方向为超硬材料的化学机械抛光工艺及机理。E-mail:nizf@jiangnan.edu.cn
  • 作者简介:陈国美,女,1982年出生,博士。主要研究方向为化学机械抛光。E-mail:cgm0208@163.com
  • 基金资助:
    国家自然科学基金(51305166,51175228)和江苏省自然科学基金(BK20130143)资助项目。

Effect of Different Oxidizers on Chemical Mechanical Polishing of 6H-SiC

NI Zifeng1, CHEN Guomei1,2, XU Laijun1, BAI Yawen1, LI Qingzhong1, ZHAO Yongwu1   

  1. 1. School of Mechanical Engineering, Jiangnan University, Wuxi 214122;
    2. School of Mechanical and Electrical Engineering, Wuxi Vocational Institute of Commerce, Wuxi 214122
  • Received:2017-10-11 Revised:2018-05-09 Online:2018-10-05 Published:2018-10-05

摘要: 选用胶体SiO2纳米颗粒为磨粒,研究不同pH值条件下高锰酸钾和双氧水两种氧化剂对6H-SiC晶片化学机械抛光的影响,并使用原子力显微镜观察抛光后表面质量。采用Zeta电位分析仪分析溶液中胶体SiO2颗粒的Zeta电位,采用X射线光电子能谱分析SiC抛光表面元素及其化学状态。结果表明:SiC晶片的材料去除率随pH值变化而变化,采用高猛酸钾抛光液抛光时,材料去除率在pH 6时达到峰值185 nm/h,Ra为0.25 nm;采用双氧水抛光液抛光时,材料去除率在pH 8时达到峰值110 nm/h,Ra为0.32 nm。pH值低于5时,电负性的SiO2颗粒会通过静电作用吸附在带正电的SiC表面,抑制SiC晶片表面原子的氧化及去除,降低材料去除率;pH值高于5时,SiO2颗粒在双氧水抛光液中的静电排斥力弱于高锰酸钾抛光液中静电排斥力,从而影响了SiO2颗粒的分散性能,降低了抛光效果。采用高锰酸钾抛光液抛光后,SiC晶片表面的Si-C氧化产物含量(Si-C-O、Si4C4-xO2和Si4C4O4)较高,高锰酸钾抛光液的氧化能力较强。

关键词: 二氧化硅颗粒, 高锰酸钾, 化学机械抛光, 双氧水, 碳化硅

Abstract: The chemical mechanical polishing (CMP) performance of Si-face 6H-SiC substrates are compared between two different oxidizers (KMnO4 and H2O2) under different pH values, using colloidal silica nanoparticles as abrasives. The surface morphology of the polished SiC substrate is characterized using atomic force microscope (AFM). The Zeta potentials of silica particles in different solutions are investigated using zeta potential analyzer and the chemical composition of the polished surfaces is studied using X-ray photoelectron spectroscopy (XPS). The results indicate that there is a significant difference in the material removal rates (RRs) of 6H-SiC under different pH values. For the KMnO4 based slurries, the maximum RRs (185 nm/h) with an average roughness Ra of 0.25 nm is achieved at pH 6; for the H2O2 based slurries, the maximum RRs (110 nm/h) with an average roughness Ra of 0.32 nm is achieved at pH 8. Negative charged silica particles are expected to be attracted by positive charged SiC surface below pH 5, which might reduce the oxidation and removal of the SiC substrate; the electrostatic repulsive force of silica particles in the H2O2 based slurries is less than in the KMnO4 based slurries, thus influencing the dispersion properties of silica particles. The concentrations of the oxidized species of Si-C (Si-C-O, Si4C4-xO2 and Si4C4O4) are higher in the SiC surface polished with KMnO4 than in the pre-polished SiC surface and the surface polished with H2O2, which due to the higher oxidizing ability of KMnO4 than H2O2.

Key words: chemical mechanical polishing (CMP), H2O2, KMnO4, silica particles, silicon carbide (SiC)

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