Patent ID: 6476904
Filing Date: 2002-11-05
Classification: G03B,G03F

Abstract:
A projection exposure apparatus, comprising:a projection optical system for projecting a pattern formed on a base onto a photosensitive substrate, the photosensitive substrate having a plurality of exposure shot areas; a stage, movable in a direction of an optical axis of said projection optical system and in a direction perpendicular thereto, for holding the photosensitive substrate; a stage driver for driving said stage in the direction perpendicular to the optical axis of said projection optical system between exposure shot areas of the substrate; location detection means for determining a location of said stage in the direction perpendicular to the optical axis of the projection optical system and for producing a corresponding output; adjusting means for adjusting a location of said stage in the optical axis direction during movement of said stage between the exposure shot areas of the substrate in order to align each of the plurality of exposure shot areas with an optical image forming plane; a sensor for measuring a movement displacement representing a displacement in a focusing location of the photosensitive substrate during movement of said stage between exposure shot areas of the substrate and producing a corresponding movement displacement value, and for measuring an exposure displacement representing a displacement in a focusing location of the photosensitive substrate during exposure of one of the plurality of exposure shot areas of the substrate and producing a corresponding exposure displacement value; and processing means for establishing and storing a correlation between the location of said stage in the direction perpendicular to the optical axis and an offset value, for receiving the movement displacement value for each location of said stage and subtracting the offset value corresponding to the location of said stage therefrom, and for outputting the difference to the adjusting means in order to adjust the location of said stage in accordance with the outputted difference, said processing means comprising offset means for receiving the exposure displacement value and establishing the offset value as the exposure displacement value at each of the plurality of exposure shot areas, wherein said adjusting means moves said stage a distance in the optical axis direction of said projection optical system in accordance with a determined amount of displacement corrected by the offset value while said stage moves between exposure shot areas.