| 摘要 |
A moving lattice(30X) is arranged on a side surface of a wafer stage(WST), light is applied to the moving lattice from a light source(22), diffracted light generated at the moving lattice is interfered by fixed scales(24A, 24B) wherein positional relationship with the light source is fixed and an index scale(26), and the interfered light is detected by a detector(28). In such case, since the moving lattice is arranged on the side surface of the wafer stage, size increase of the wafer stage as a whole can be suppressed. Furthermore, since the interference is generated among a plurality of diffracted beams(for instance,± primary diffracted beams) passing extremely close optical paths, there is less influence of fluctuation of the ambient atmosphere compared with the conventional interferometer, highly accurate measurement of position information of the mobile body is made possible. |
