An Exploration into Damage Repair and Manufacturing Technology of Photomask Glass Substrates

There are strict requirements on the surface-shape accuracy, cracks, scratches, and subsurface damage of photomask glass substrates with the advancement of photo-etching technology. In this study, photomask quartz glass substrates were etched with the hydrofluoric (HF) acid etching method after chemical mechanical polishing (CMP), so that the polishing hydrolysis layer could be completely removed. In addition, the surface scratches caused by CMP were observed with a surface quality detection device and a white light interferometer. Second, the high-efficiency array-type magnetorheological polishing technology was employed to eliminate the surface-shape error on the surface of quartz photomask glass substrates. Finally, the removal function rotation angle based magnetorheological polishing technology was utilized to evenly remove the mid-frequency ripples and scratches caused in the preceding technological process. The experimental results demonstrated that these technologies can be used to realize rapid damage removal and high-quality processing of photomask glass substrates.