Development of binder-free CMG abrasive pellet and finishing performance on mono-crystal sapphire

• Published in: Precision engineering 2020-03, Vol.62, p.40-46
• Main Authors: Wang, Jianbin, Wu, Ke, Maezaki, Tomohiro, Zhou, Libo, Onuki, Teppei, Shimizu, Jun, Zhu, Yongwei
• Format: Article
• Language: English
• Subjects: Binder-free abrasive pellet; Chemo-mechanical-grinding; Cold isostatic pressure; Material removal rate; Surface and subsurface integrity
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/j.precisioneng.2019.11.004

Chemo-mechanical-grinding (CMG) is a fixed abrasive process by integrating chemical reaction and mechanical grinding for sapphire wafer finishing, and shows advantages in surface integrity, geometric controllability and waste disposal. However, the material removal rate (MRR) obtained by the traditional CMG wheel is not high enough to meet the requirement from the mass production of sapphire wafers. As a potential solution, a new CMG wheel with extremely high abrasive concentration has been proposed. This paper targets on developing of binder-free abrasive pellets (BAP) with 100 wt% abrasive as well as investigating the performance of BAP in sapphire wafer finishing. The results of CMG experiment reveal that the MRR and surface roughness (Ra) of sapphire wafer finished by BAP constructed CMG wheel are able to reach 1.311 μm/h and 0.993 nm respectively. The characterization by Raman microscope indicates that the finished sapphire wafer also owns excellent subsurface integrity. •The binder-free abrasive pellet with 100 wt% Cr2O3 abrasives has been successfully developed.•Both MRR and wheel/pellet wear ratio increase as the Cr2O3 abrasives concentration becomes higher.•The developed BAP-CMG wheel provides a finishing capability of sapphire with MRR = 1.311 μm/h and Ra < 1 nm.•The developed BAP-CMG wheel grants high surface/subsurface integrity of sapphire wafer.