ArF-laser-induced photochemical super mirror-finishing of Si wafer (Abstract Only)

摘要

Si wafer was polished accurately with ArF laser irradiation in the presence of the hydrofluoric acid water solution. The highest surface accuracy of Si wafer is needed for the Si substrate for using extremely ultra violet (EUV) lithography. Then we tried to polish the SiO2 with hydrofluoric acid water solution, which was photo-oxidized Si wafer surface with active oxygen. The active oxygen was photo-dissociated from water (H2O). The Si wafer surface was pressurized at 50g/cm2 on the fluorocarbon-polishing mat. Next the hydrofluoric acid water solution is infiltrated into the thin gap between the sample and the fluorocarbon. And ArF laser is irradiated through the fluorocarbon turntable. By this irradiation, the Si wafer surface was oxidized and produced SiO2. The moment it is dissolved by HF solution. After the etching, the polishing progresses by the friction with the fluorocarbon. The surface roughness was obtained 3 nm with 30 minute polishing with the ArF laser irradiation (20 mJ/cm2, 100 pps) in 15% HF/H2O ambience.