Patent ID: 9423703
Filing Date: 2016-08-23
CPC Classification: G01B,G01D,G03F,Y10T

Claim Text:
1. A scanning exposure apparatus having an illumination optical system that illuminates a mask with illumination light and a projection optical system that projects a pattern image of the illuminated mask onto a substrate, the apparatus comprising: a body having a frame member that supports the projection optical system; a mask stage system that has a first movable body and a first motor, the first movable body being placed above the projection optical system and holding the mask, and the first motor driving the first movable body; a first encoder system that has a plurality of first heads each irradiating a first measurement beam to a first grating section having a reflection type grating, and measures positional information of the first movable body moved by the first motor, the reflection type grating being placed substantially parallel to a predetermined plane orthogonal to an optical axis of the projection optical system; a substrate stage system having a second movable body and a second motor, the second movable body being placed below the projection optical system and holding the substrate, and the second motor driving the second movable body; a second encoder system that has four second heads each irradiating a second measurement beam to a second grating section having four scales, and measures positional information of the second movable body moved by the second motor, the four scales each having a reflection type grating placed substantially parallel to the predetermined plane; and a controller coupled to the mask stage system and the substrate stage system, that controls a drive of the first movable body by the first motor based on measurement information of the first encoder system and also controls a drive of the second movable body by the second motor based on measurement information of the second encoder system so that the mask and the substrate are each moved relative to the illumination light in a scanning exposure of the substrate, wherein the plurality of first heads include two first heads that are different in position in a first direction which is orthogonal to the optical axis of the projection optical system and in which the mask is moved in the scanning exposure, and one first head that is different in position from the two first heads in a second direction orthogonal to the optical axis and orthogonal to the first direction, at least in an exposure operation of the substrate, a relationship between the second grating section and the four second heads changes between a first state and a second state by a movement of the second movable body, wherein at least during the scanning exposure, three scales of the four scales are always faced by three of the four second heads.