Patent ID: 6867849

Claim:
An exposure apparatus comprising: as a reticle stage and/or a wafer stage, a stage apparatus having a stage movable at least on a long stroke along a first direction and a short stroke along a second direction, a first optical unit which is arranged outside the stage and splits a first laser beam for measuring a position of the stage in the first direction into first reference and measurement beams, a second optical unit which splits a second laser beam for measuring a position of the stage in the second direction into second reference and measurement beams, a third optical unit which is arranged on the stage and irradiates a third laser beam along a third direction for measuring a position of the stage in the third direction perpendicular to each of the first and second directions, a first reflection unit which is arranged on the stage and reflects the first measurement beam, a second reflection unit which is arranged outside the stage and reflects the second measurement beam, a first detector which is arranged outside the stage and detects an interference beam of the first measurement and reference beams, and a second detector which is arranged outside the stage and detects an interference beam of the second measurement and reference beams.