| 主权项 |
1. An exposure apparatus that exposes each of a plurality of divided areas on an object with illumination light via a projection optical system, the apparatus comprising:
a base member having an upper surface arranged substantially parallel to a predetermined plane perpendicular to an optical axis of the projection optical system; a stage arranged on the base member and having a holder that holds the object; a drive system that has a planar motor having a coil unit and a magnet unit, and drives the stage supported by levitation on the base member so that the object is moved in directions of six degrees of freedom including a first direction and a second direction orthogonal to each other within the predetermined plane, one of the coil unit and the magnet unit of the planar motor being provided at one of the base member and the stage and the other of the coil unit and the magnet unit being provided at the other of the base member and the stage; a measurement system that has four heads provided at the stage and each irradiating a measurement beam to a scale member from below, and that measures positional information of the stage in the directions of six degrees of freedom, the scale member having four sections in each of which a reflection-type grating is formed; and a control system coupled to the drive system and the measurement system, that controls a drive of the stage by the drive system based on the positional information measured by the measurement system, and switches one head used for the measurement to another head during the drive of the stage, wherein the scale member has an opening defined by the four sections, and is arranged so that the projection optical system is positioned in the opening in the first and the second directions, the four heads are arranged at the stage so that a distance between two heads of the four heads is larger than a width of the opening in the first direction and also a distance between two heads of the four heads is larger than a width of the opening in the second direction, a movement area where the stage is moved in an exposure operation of the object includes a first area, a second area, a third area, a fourth area and a fifth area,
in the first area three heads of the four heads except for a first head respectively facing three sections of the four sections except for a first section,in the second area three heads of the four heads except for a second head different from the first head respectively facing three sections of the four sections except for a second section different from the first section,in the third area three heads of the four heads except for a third head different from the first and the second heads respectively facing three sections of the four sections except for a third section different from the first and the second sections,in the fourth area three heads of the four heads except for a fourth head different from the first, the second and the third heads respectively facing three sections of the four sections except for a fourth section different from the first, the second and the third sections, andin the fifth area the four heads respectively facing the four sections, in the exposure operation of the object, the drive system moves the stage from one area of the first, the second, the third and the fourth areas to another area of the first, the second, the third and the fourth areas that is different from the one area, via the fifth area, and the control system switches the one head to the another head when the stage is moved from the fifth area to the another area. |
