Mechanism and Experimental Investigation on Silicon Wafer Hybrid Polishing by Ultrasonic-Elliptic-Vibration Chemical-Mechanical

Abstract:

Considering the technical status and existing problems of traditional silicon wafer chemical mechanical polishing (CMP), especially for the diameter of silicon wafer increasing, constantly, the surface quality and efficiency of silicon wafer polishing are becoming an urgent problem to be solved, so the research subject of ultrasonic vibration hybrid polishing new technique was proposed. By means of mechanism theoretical analysis research, firstly, the processing mechanism of hybrid polishing was studied systematically. An investigation of polishing mechanisms based on the micro-contact model between the polishing pad and the polishing surface of silicon wafer was developed. Polishing mechanism theoretical analysis shows that when ultrasonic vibrations combined with mechanical and chemical, the performance of polishing slurry is improved in the process of CMP, therefore to create favorable conditions. To verify the established theory, then, a series of experiments to investigate the traditional CMP are conducted, as well as the polishing tool with the forms of ultrasonic vibration, the polishing pad, the polishing surface quality, velocity at polishing point v, and slurry supplying Q on silicon wafer polishing. Experiment findings showed that, in the same polishing conditions, especially, hybrid polishing by ultrasonic-elliptic-vibration has gained more advantage over the effect of silicon wafer polishing. When ultrasonic-elliptic-vibration is put in polishing tool, the silicon wafer polished surface roughness Ra from the traditional method of polishing 0.077μm going down to the 0.042μm, the no-smooth rate KR which describes the polished surface morphology is significantly improved, and the material removal rate increases by 18%. Experimental research findings of the surface quality and the material removal mechanism are shown to be consistent with the theoretical analysis.

• Periodical: Advanced Materials Research (Volumes 314-316)
• Pages: 829-836
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.314-316.829
• Online since: August 2011
• Authors: Wei Ping Yang, Yong Bo Wu, Hong Fei Yang
• Keywords: CMP, Contact Mode, CZ Silicon Wafer, Hybrid, Mechanism, Ultrasonic-Elliptic-Vibration

References

[1] Imai M, Mayusumi M, Inoue K, et al: Issues for the larger diameter epitaxial wafer. Microelectronic Engineering, Vol. 56(1-2) (2001), pp.109-115

DOI: 10.1016/s0167-9317(00)00511-6

[2] Jianxiu Su, Renke Kang, Dongming Guo: Technology analysis of wafer chemical mechanical polishing in the manufacture of ULSI. Semiconductor Technology, Vol. 28(10), pp.50-51 (In Chinese)

[3] Weiping Yang, Yongbo Wu and Masana Kato: A new approach to silicon wafer edge treatment by ultrasonically assisted polishing (UAP). International Journal of Materials and Product Technology, Vol. 31(2-4) (2008), pp.159-175

DOI: 10.1504/ijmpt.2008.018017

[4] Huidong Xie, Xiaoqing Wang and Guangqiu Shen: Superpolishing of Crystals. Journal of Synthetic Crystals, Vol. 33(6) (2004), pp.1035-1040 (In Chinese)

[5] Weiping Yang, Jiawen Xu: Measurement of material micro remove rate with roughness measuring instrument. Tool Engineering, (10) (2007), pp.50-51 (In Chinese)