光学石英玻璃CMP抛光液的研究

Research on the CMP Slurry for the Optical Quartz Glass

针对光学石英玻璃在表面化学机械抛光(CMP)过程中易出现表面及亚表面损伤和蚀坑等缺陷问题,提出了采用低抛光压力和低磨料体积分数的CMP方法。机械作用是引起表面及亚表面损伤的关键因素,低抛光压力可以有效降低抛光过程中施于晶体表面的机械作用,抛光液中低磨料体积分数既可降低一定的机械作用又可降低由于高磨料体积分数引起的表面沾污。在降低机械作用的基础上,为获得较高的去除速率和较佳的表面质量,选用大分子胺碱作为pH调节剂,以增加质量传递作用。通过大量实验证实,粒径60 nm的硅溶胶磨料体积分数为8%、活性剂体积分数为5%、螯合剂体积分数为1%、pH值为9和抛光压力为1 psi(1 psi=6 895 Pa)的条件下,可获得较高的去除速率和较佳的表面质量,此时的去除速率为52.8 nm/min、表面粗糙度为0.126 nm。此结果可对业内此类材料的超精密加工提供一定的参考。

The chemical mechanical polishing（CMP）method of low pressure and low abrasive volume fraction was proposed to solve the defect issues of the surface or sub-surface damages and etch pits which easily occur in the optical quartz glass during the CMP process.The mechanical action is the key factor causing the surface or sub-surface damages.The lower polishing pressure can reduce the mechanical action forced on the crystal surface effectively during the polishing process,and the slurry with lower abrasive volume fraction can reduce the mechanical action and surface contamination caused by high abrasive volume fraction.In order to obtain higher removal rate and lower surface roughness on the basis of reducing the mechanical action,the macromolecule amine alkali was used as the pH conditioning agent to strengthen the mass transfer function.A large number of experiments results show that the higher removal rate and lower surface roughness can be obtained under the conditions of 8% silica solution abrasive volume fraction with the particle size of 60 nm,5% surfactant volume fraction,1% chelating agent volume fraction,the pH value of 9 and 1 psi（1 psi=6 895 Pa）polishing pressure.Finally,the obtained removal rate is 52.8 nm/min and the surface roughness is 0.126 nm,which can provide a reference for the ultraprecise machining of this type of the material in the industry.