| 主权项 |
1. An exposure apparatus that exposes a substrate with an illumination light via a projection optical system, the apparatus comprising:
a first stage placed above the projection optical system, that holds a mask illuminated with the illumination light; a first drive system having a motor to drive the first stage; a first encoder system that measures positional information of the first stage; a base placed below the projection optical system; a second stage placed on the base and having 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 so that the substrate is moved in directions of six degrees of freedom, the planar motor levitating the second stage on the base, a part of the planar motor being provided at the second stage, and the directions of six degrees of freedom including a first direction and a second direction orthogonal to each other in a predetermined plane perpendicular to an optical axis of the projection optical system; a second encoder system that has four heads provided at the second stage and measures positional information of the second stage in the directions of six degrees of freedom, the four heads each irradiating a measurement beam to a scale member from below, the scale member having four sections and an opening, and each of the four section having a reflection-type grating formed; and a controller that controls the first drive system and the second drive system based on measurement information of the first encoder system and measurement information of the second encoder system, respectively, wherein the scale member is provided on a lower end side of the projection optical system so that the projection optical system is located in the opening, the controller controls the first and the second drive systems so that the mask and the substrate are moved relative to the illumination light, respectively, in scanning exposure of the substrate, 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 one head and two heads respectively facing three sections consisting of one section and two sections, the one 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 one 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, and controls the second drive system based on correction information for compensating for a measurement error of the second encoder system and positional information measured by the three heads used in the another second area, in order to move the second stage in the another second area, the measurement error 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. |
