Patent ID: 8514373

Claim:
An exposure apparatus that exposes a substrate with an illumination beam via a projection optical system, the apparatus comprising: a frame structure that supports the projection optical system; a stage system which has a substrate stage placed under the projection optical system that is supported by the frame structure and an electromagnetic motor coupled to the substrate stage, and which moves the substrate by driving the substrate stage by the electromagnetic motor, the substrate stage including a substrate mounting portion, the substrate being mounted on an upper side of the substrate mounting portion, and a grating surface being placed on a lower side of the substrate mounting portion and having a grating area where a grating is formed; and an encoder system which has an optical member supported to be placed lower than the grating surface by the frame structure, and which irradiates the grating surface with a measurement beam from below via the optical member to measure positional information of the substrate stage, the optical member facing the grating surface as the substrate stage is placed facing the projection optical system, wherein the grating surface is moved relative to the optical member in a first direction and a second direction orthogonal to an optical axis of the projection optical system and orthogonal to each other as the substrate stage moves, the measurement beam is irradiated on the grating so that a measurement point irradiated with the measurement beam is not moved off from the grating area which is moved relative to the optical member, with respect to the first and the second directions, during at least an exposure operation of the substrate, and the measurement point is located under an exposure area on which the illumination beam is irradiated via the projection optical system and within the exposure area with respect to the first and the second directions.