| 主权项 |
1. An exposure apparatus that exposes a substrate with illumination light via a projection optical system, the apparatus comprising:
a first stage that is disposed above the projection optical system and holds a mask illuminated with the illumination light; a first drive system that has a motor to drive the first stage; a first encoder system that measures positional information of the first stage; a base member disposed below the projection optical system; a second stage that is disposed on the base member and has a holder to hold the substrate; a second drive system that has a planar motor of a magnetic levitation type and drives the second stage, the planar motor supporting the second stage by levitation on the base member; a second encoder system that has four heads provided at the second stage and measures positional information of the second stage, each of the four heads irradiating a scale member from below with a measurement beam, the scale member having four sections and an opening surrounded by the four sections, and each of the four sections having a reflection-type grating formed; and a controller that is coupled to the first and the second drive systems, and controls the first drive system based on measurement information of the first encoder system and also controls the second drive system based on measurement information of the second encoder system in order to move the mask and the substrate relative to the illumination light, respectively, in scanning exposure of the substrate, wherein the scale member is disposed on a lower end side of the projection optical system so that the projection optical system is located in the opening, the four heads are provided at the second stage so that a distance between two heads of the four heads is larger than a width of the opening, the controller
controls the second drive system so that the second stage is moved in a movement area that includes a first area and four second areas, in the first area the four heads respectively facing the four sections, and each of the four second areas having a part different from the first area,controls the second drive system so that the second stage is moved from one second area of the four second areas to another second area, different from the one second area, of the four second areas, via the first area,
in the one second area, three heads of the four heads respectively facing three sections of the four sections, andin the another second area, three heads consisting of another head and two heads respectively facing three sections consisting of another section and two sections, the another head being of the four heads and being different from the three heads used in the one second area, the two heads being of the three heads used in the one second area, the another section being of the four sections and being different from the three sections used in the one second area, and the two sections being of the three sections used in the one second area, andcontrols the second drive system based on correction information for compensating for a measurement error of the second encoder system and positional information measured with the three heads used in the another second area, in order to move the second stage in the another second area, the measurement error of the second encoder system occurring due to performing drive control of the second stage by the three heads used in the another second area, instead of drive control of the second stage by the three heads used in the one second area, and the correction information is acquired from positional information obtained from the four heads while the second stage is in the first area. |
