Surface roughness of optical quartz substrate by chemical mechanical polishing

In order to achieve a high-quality quartz glass substrate and to improve the performance of TiO2 anti-reflection coating, chemical mechanical polishing (CMP) method was used. During CMP process, some process parameters including pressure, polishing head speed, platen speed, slurry flow rate, polishing time, and slurry temperature were optimized to obtain lower quartz surface roughness. According to the experiment results, when pressure was 0.75 psi, polishing head speed was 65 rpm, platen speed was 60 rpm, slurry flow rate 150 mL/min, slurry temperature 20 °C, and polishing time was 60 s, the material removal rate (MRR) was 56.8 nm/min and the surface roughness (Ra) was 1.93 Å (the scanned area was 10 × 10 μm2). These results were suitable for the industrial production requirements.