Projection exposure method and apparatus

A device fabrication method comprising:

• projecting a pattern formed on a base onto a photosensitive substrate, the photosensitive substrate having a plurality of exposure shot areas;
• providing a stage, movable in a direction of an optical axis of the projection optical system and in a direction perpendicular thereto, for holding the photosensitive substrate;
• driving the stage in the direction perpendicular to the optical axis of the projection optical system between exposure shot areas of the substrate;
• determining a location of the stage in the direction perpendicular to the optical axis of the projection optical system, and producing a corresponding output;
• adjusting a location of the stage in the optical axis direction during movement of the 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;
• measuring, with a sensor, (i) a movement displacement representing a displacement in a focusing location of the photosensitive substrate during movement of the stage between exposure shot areas of the substrate and producing a corresponding movement displacement value, and (ii) 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;
• establishing and storing a correlation between the location of the stage in the direction perpendicular to the optical axis and an offset value;
• receiving the movement displacement value for each location of the stage and subtracting the offset value corresponding to the location of the stage therefrom;
• outputting the difference to the adjusting step in order to adjust the location of the stage in accordance with the outputted difference;
• and
• 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 step moves the stage a distance in the optical axis direction of the projection optical system in accordance with a determined amount of displacement corrected by the offset value while the stage moves between exposure shot areas.

A projection exposure apparatus, comprising:

• a projection optical system for projecting a pattern formed on an original onto a photosensitive substrate, the photosensitive substrate having a plurality of exposure shot areas thereon;
• 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 said 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 position representing a position of the photosensitive substrate during movement of said stage between exposure shot areas of the substrate and producing a corresponding movement position value, and for measuring an exposure position representing a position of the photosensitive substrate during exposure of one of the plurality of exposure shot areas of the substrate and producing a corresponding exposure position 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 a shift value, for receiving the movement position value for each location of said stage and subtracting the shift value corresponding to the location of said stage therefrom, and for outputting the difference to said adjusting means in order to adjust the location of said stage in accordance with the outputted difference, said processing means comprising shift means for receiving the exposure position value and establishing the shift value as the distance between the exposure position value and the optical image forming plane 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 shift value while said stage moves between exposure shot areas.

An 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 first measuring member for measuring a displacement in a focusing location of each of the exposure shot areas during a period in which the photosensitive substrate moves between each of the exposure shot areas and for producing a first measurement result;
• a second measuring member for measuring the displacement in the focusing location of each of the exposure shot areas after movement of the photosensitive substrate is completed and for producing a second measurement result;
• a correcting member for correcting the first measurement result from said first measuring member in accordance with the second measurement result from said second measuring member, and for outputting a correction result;
• and
• an adjusting member for adjusting a relative position of the photosensitive substrate to said projection optical system in accordance with the correction result from said correcting member.

A device fabrication method comprising:

• projecting a pattern formed on a base onto a photosensitive substrate by a projection optical system, the photosensitive substrate having a plurality of exposure shot areas;
• measuring a displacement in a focusing location of each of the exposure shot areas during a period in which the photosensitive substrate moves between each of the exposure shot areas and producing a first measurement result;
• measuring the displacement in the focusing location of each of the exposure shot areas after movement of the photosensitive substrate is completed and producing a second measurement result;
• correcting the first measurement result in accordance with the second measurement result, and outputting a correction result;
• and
• adjusting a relative position of the photosensitive substrate to the projection optical system in accordance with the correction result.