Abstract: In order to investigate the effect of lapping plate materials on surface roughness and uniformity, experimental research is performed with W14 and W3.5 boron carbide abrasives for lapping sapphire wafer. In rough lapping process, cast iron, synthetic copper and synthetic tin lapping plate are used to machine sapphire wafer with W14 boron carbide abrasive, experimental results show that the best macro-uniformity and flatness are achieved by cast iron lapping plate. Sapphire wafer surface with surface error of peak-valley value less than 5 µm, standard deviation of roughness less than 0.82 µm are achieved. In precision lapping process, synthetic copper lapping plate is used to conduct the experiment with W3.5 boron carbide abrasive, both roughness and uniformity are greatly improved, a better surface quality with average deviation of roughness less than 20 nm, surface error of peak-valley value less than 1.6 µm is gotten by precision lapping process, which meet the demands of ultra-precision lapping process.

Key words: Lapping plate, Sapphire wafer, Surface roughness, Surface uniformity