Position detection apparatus, machine tool apparatus, and exposure apparatus

A machine tool apparatus comprising:

• a machine tool including at least one of a robot arm and a conveyer configured to convey an object to be assembled, and
• a position detection apparatus configured to detect at least one of a position and an attitude of the machine tool,
• wherein the position detection apparatus comprises:
• a scale including a reference position grating configured to change a pattern period along a first direction;
• a detector including a light source configured to emit a divergent light beam, a detection grating configured to change a pattern period in the first direction, and a light receiver including a plurality of light receiving elements arrayed along the first direction;
• and
• a signal processor configured to process a signal output from the detector, wherein:
• the scale and the detector are relatively movable in the first direction,
• the signal processor acquires a relative reference position between the scale and the detector by using a light intensity distribution of the divergent light beam obtained via the reference position grating and the detection grating,
• the detection grating has a first spatial frequency that is offset by a predetermined frequency offset amount with respect to a local spatial frequency of an interference image from the reference position grating,
• the detection grating is provided in an optical path between the scale and the light receiver, and
• the light receiver detects a component of a second spatial frequency that is lower than the first spatial frequency in the light intensity distribution transmitting through the detection grating.

An exposure apparatus comprising:

• a stage configured to mount a semiconductor wafer to be movable in a two-dimensional direction;
• and
• a position detection apparatus configured to detect a position of the stage,
• wherein the position detection apparatus comprises:
• a scale including a reference position grating configured to change a pattern period along a first direction;
• a detector including a light source configured to emit a divergent light beam, a detection grating configured to change a pattern period in the first direction, and a light receiver including a plurality of light receiving elements arrayed along the first direction;
• and
• a signal processor configured to process a signal output from the detector, wherein:
• the scale and the detector are relatively movable in the first direction,
• the signal processor acquires a relative reference position between the scale and the detector by using a light intensity distribution of the divergent light beam obtained via the reference position grating and the detection grating,
• the detection grating has a first spatial frequency that is offset by a predetermined frequency offset amount with respect to a local spatial frequency of an interference image from the reference position grating,
• the detection grating is provided in an optical path between the scale and the light receiver, and
• the light receiver detects a component of a second spatial frequency that is lower than the first spatial frequency in the light intensity distribution transmitting through the detection grating.