Abstract: Double-sided lapping is an important process in manufacturing the sapphire substrate.The main purpose is to remove the cutting marks on the wafer surface and make surface roughness homogeneous,at the same time,improve the wafer surface shape accuracy,make its meet certain specifications.The changing process of sapphire substrate surface shape (Warp, Bow and TTV) and surface roughness in double-sided lapping was studied by carrying out lapping experiments.In the initial stage of double-sided lapping,Warp decreases rapidly,Bow decreases slow,while TTV and the surface roughness Ra increase rapidly,but then,Warp,TTV and the surface roughness Ra have a little decrease with an increase of material removal.Bow decreases gradually to a stable value as the material removal increases.The research results have an important significance to optimize processing,improve machining precision and machining efficiency for double-sided lapping sapphire wafer.

Key words: sapphire, double-sided lapping, accuracy of surface shape, roughness, removal