Novel model of material removal rate on ultrasonic-assisted chemical mechanical polishing for sapphire  

作　　者：Mufang ZHOU Min ZHONG Wenhu XU 

机构地区：[1]Department of Mechanical Engineering,Key Laboratory of Tribology,Nanchang University,Nanchang 330031,China

出　　处：《Friction》2023年第11期2073-2090,共18页摩擦（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.51865030 and 52165025).

摘　　要：Ultrasonic-assisted chemical mechanical polishing(UA-CMP)can greatly improve the sapphire material removal and surface quality,but its polishing mechanism is still unclear.This paper proposed a novel model of material removal rate(MRR)to explore the mechanism of sapphire UA-CMP.It contains two modes,namely two-body wear and abrasive-impact.Furthermore,the atomic force microscopy(AFM)in-situ study,computational fluid dynamics(CFD)simulation,and polishing experiments were conducted to verify the model and reveal the polishing mechanism.In the AFM in-situ studies,the tip scratched the reaction layer on the sapphire surface.The pit with a 0.22 nm depth is the evidence of two-body wear.The CFD simulation showed that abrasives could be driven by the ultrasonic vibration to impact the sapphire surface at high frequencies.The maximum total velocity and the air volume fraction(AVF)in the central area increased from 0.26 to 0.55 m/s and 20%to 49%,respectively,with the rising amplitudes of 1–3μm.However,the maximum total velocity rose slightly from 0.33 to 0.42 m/s,and the AVF was nearly unchanged under 40–80 r/min.It indicated that the ultrasonic energy has great effects on the abrasive-impact mode.The UA-CMP experimental results exhibited that there was 63.7%improvement in MRR when the polishing velocities rose from 40 to 80 r/min.The roughness of the polished sapphire surface was R_(a)=0.07 nm.It identified that the higher speed achieved greater MRR mainly through the two-body wear mode.This study is beneficial to further understanding the UA-CMP mechanism and promoting the development of UA-CMP technology.

关 键 词：SAPPHIRE ultrasonic-assisted chemical mechanical polishing(UA-CMP) material removal rate(MRR)predictive model atomic force microscopy(AFM)in-situ studies computational fluid dynamics(CFD) 

分 类 号：TB306[一般工业技术—材料科学与工程]