化学机械抛光工艺参数对氧化锆陶瓷抛光速率的影响

Effects of Chemical-mechanical Polishing Parameters on Material Removal Rate of Zirconia Ceramic

目的探究SiO_2磨料固含量、抛光垫和下压力等工艺参数对氧化锆陶瓷化学机械抛光速率的影响和作用机理。方法采用粒径为80 nm的钠型稳定型硅溶胶,氢氧化钠溶液作为pH调节剂,将硅溶胶pH调至为10。通过CP-4抛光设备进行氧化锆陶瓷抛光实验及摩擦系数采集,采用黏度测试仪测试不同固含量硅溶胶的黏度,采用扫描电子显微镜分析了SUBA系列两种抛光垫的微观结构。结果硅溶胶固含量为37%时,抛光速率最快,达到54.3 nm/min,此时摩擦系数最小,为0.1501。随着固含量的增加,摩擦系数小幅增加,并稳定在0.1540附近。硅溶胶固含量高于37%的抛光机制是流体力学作用的结果,固含量低于37%的抛光机制是流体力学和机械力共同作用的结果。扫描电镜下观察发现,SUBA800抛光垫的孔隙尺寸比SUBA600抛光垫的孔隙尺寸小,使用前者的抛光速率快于后者,抛光速率相差10 nm/min。因为孔隙多改变了硅溶胶和抛光垫的接触机制,增大了切应力和摩擦系数,机械作用力加强,从而加快了抛光速率。摩擦系数与下压力没有关系,下压力小于3.5 psi时,抛光速率符合Preston方程。结论对氧化锆陶瓷进行化学机械抛光处理,固含量在37%时,抛光速率最快。SUBA800抛光垫相比SUBA600抛光垫,更适合氧化锆陶瓷抛光。下压力小于3.5 psi时,抛光速率符合Preston方程行为,且摩擦系数和下压力没有关系。

The work aims to investigate mechanisms of influence and action of different process parameters including Si02 abrasive solid content,polishing pad and down pressure on chemico-mechanical polishing(CMP)rate of zirconia ceramic.pH of silica sol was regulated to 10 by using sodium-type steady silica sol with particle size of 80 nm and sodium hydroxide solution(as pH regulator).CP-4 polisher was used to performzirconia ceramics polishing experiment and collect coefficient of friction,and viscosity tester was used to test viscosity of silica sol of different solid content,and scanning electron microscope(SEM)was used to analyze microstructure of two SUBA series polishing pads.When the solid content of silica sol was 37%,the material removal rate(MRR)was the quickest(54.3 nm/min),and COF was the minimum(0.1501).Continuous increase of solid content was accompanied by slight increase of COF which remained at around 0.1540.The polishing mechanism in which solid content of silica sol was over 37%was the result of hydromechanics,while the polishing mechanism in which solid content of silica sol was below 37%was the result of hydromechanics and mechanics.Compared with microstructure of SUBA600 polishing pad,that of SUBA800 polishing pad exhibited more and smaller pores.The MRR of SUBA800 was 10 nm/min higher than that of SUBA600,since abundant pores have changed the contact mechanism of silica sol and polishing pads,increased shear force and COF,and intensified mechanical effect,which further accelerated polishing rate.The COF had no connection with down pressure.The MRR conformed to Prestx>n equation when the down pressure was lower than 3.5 psi.For the CMP of zirconia ceramics,MRR is the quickest at the solid content of 37%.SUBA800 is more suitable for zirconia ceramics polishing than SUBA600.If the down pressure is below 3.5 psi,the MRR conforms to Preston equation and COF has no connection with down pressure.