CPC G03F 7/70133 (2013.01) [G01B 11/00 (2013.01); G01B 11/26 (2013.01); G03F 7/70058 (2013.01); G03F 7/70775 (2013.01); H01J 37/3045 (2013.01); H01J 37/3174 (2013.01); H01J 2237/202 (2013.01); H01J 2237/3175 (2013.01)] | 15 Claims |
1. An exposure apparatus that exposes a substrate with an illumination light via a projection optical system, the apparatus comprising:
a stage having a table that holds the substrate and a main body section that supports the table in a non-contact manner;
a drive system having a planar motor that moves the main body section, the system driving the table in directions of six degrees of freedom, the directions of six degrees of freedom including a first direction and a second direction orthogonal within a predetermined plane, which is orthogonal to an optical axis of the projection optical system, and a third direction orthogonal to the first and second directions;
a focus sensor disposed apart from the projection optical system in a direction parallel to the predetermined plane, the focus sensor detecting position information of the substrate in the third direction;
a scale member having four sections disposed to substantially surround a lower end part of the projection optical system, in each of which a reflective grating is formed;
an encoder system having four head groups, with each of the groups having a plurality of heads, provided at the table to measure position information of the table in the directions of six degrees of freedom by three or four of the four head groups that face three or four of the four sections, respectively, each of the plurality of heads irradiating the reflective grating from below with a measurement beam; and
a controller coupled to the drive system and the encoder system, the controller controlling the drive system so that with a detection operation of the substrate being performed by the focus sensor prior to an exposure operation of the substrate, focus-leveling control of the substrate is also performed, based on detection information of the focus sensor and measurement information of the encoder system during the exposure operation;
wherein each of the four head groups facing the four sections measures the measurement information so that difference data of the position information is acquired by the plurality of heads in at least one of two directions orthogonal to each other within the predetermined plane, and
the controller compensates a grid error due to grid variation caused by the reflective grating in each of the four sections in a direction parallel to the predetermined plane, based on the difference data.
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