Patent ID: 9547242
Date: 2017-01-17
CPC Classifications: G01B,G03F

Claim:
1. A lithography apparatus that forms a pattern on a substrate, the apparatus comprising: an optical unit including a plurality of optical systems each of which irradiates the substrate with a beam for forming the pattern and is arranged in at least one of a first direction or a second direction orthogonal to an optical axis thereof; and a pair of interferometers configured to measure a rotation angle of the optical unit around an axis parallel to the optical axis, wherein a distance between measurement axes of the pair of interferometers is not smaller than a longer distance, which is a longer one of a first distance between optical axes of two optical systems, among the plurality of optical systems, farthest away from each other in the first direction or a second distance between optical axes of two optical systems, among the plurality of optical systems, farthest away from each other in the second direction.