Exposure apparatus and article manufacturing method
An exposure apparatus comprises a projection optical system for projecting a pattern of a mask, a substrate stage for holding a substrate, and a measurement device installed on the substrate stage, including a plate on which a substrate-side mark is formed, and a sensor for detecting light transmitted through a mask-side mark, the projection optical system, and the substrate-side mark, and configured to measure an amount of the light detected by the sensor. The substrate-side mark includes a central mark arranged in a center of a sensitive region of the sensor, and a peripheral mark arranged in a periphery of the central mark. The central mark is used in measurement of the light amount, including driving the substrate stage in a direction parallel to an optical axis of the projection optical system.
1. An exposure apparatus comprising:
a projection optical system configured to project a pattern of a mask held on a mask stage;
a substrate stage movable while holding a substrate; and
a measurement device installed on the substrate stage, including a plate on which a substrate-side mark is formed, and a sensor for detecting light transmitted through a mask-side mark formed on the mask or the mask stage, the projection optical system, and the substrate-side mark, and configured to measure an amount of the light detected by the sensor,
wherein the substrate-side mark includes a plurality of measurement marks including a central mark arranged in a center of a sensitive region of the sensor, and a peripheral mark arranged in a periphery of the central mark, and the central mark is a mark to be used in measurement of the light amount, which includes driving the substrate stage in a first direction parallel to an optical axis of the projection optical system, and the peripheral mark is a mark to be used in an alignment in a direction perpendicular to the first direction.
2. The apparatus according to claim 1 , wherein the central mark is a mark to be used in a process of measuring telecentricity indicating an inclination of principal light of the projection optical system.
3. The apparatus according to claim 2 , wherein the process of measuring the telecentricity includes a process of obtaining an amount of positional deviation from the central mark in a second direction perpendicular to the first direction, which occurs when the substrate stage is driven in the first direction, of an image of the mask-side mark projected by the projection optical system.
4. The apparatus according to claim 1 , wherein the central mark is a mark to be used in a process of determining a best focus position in the first direction by measuring the light amount while driving the substrate stage in the first direction.
5. The apparatus according to claim 1 , wherein the central mark is a mark used in a process of measuring the light amount while performing driving in a second direction perpendicular to the first direction at each position of the first direction, thereby determining an amount of positional deviation from the central mark in the second direction, of an image of the mask-side mark projected by the projection optical system.
6. The apparatus according to claim 5 , wherein the central mark includes a first central mark having a single opening having a shape extending in a third direction parallel to a surface of the sensitive region and perpendicular to the second direction, and the first central mark is arranged in a central position of the sensitive region in the second direction.
7. The apparatus according to claim 6 , wherein the central mark further includes a second central mark having a single opening having a shape extending in the second direction, and the second central mark is arranged in a central position of the sensitive region in the third direction.
8. The apparatus according to claim 6 , wherein the central mark further includes a pair of third central marks, each having a single opening, arranged in positions on a central line of the sensitive region, which is parallel to the second direction or the third direction, and symmetrical with respect to a center of the sensitive region.
9. The apparatus according to claim 1 , wherein the peripheral mark includes an alignment mark for aligning the plate and the sensitive region.
10. The apparatus according to claim 9 , wherein the alignment mark includes an opening and a scale,
an end face of the sensitive region is measured, in a state in which a surface of the sensitive region is focused through the opening, and
a positional deviation between the plate and the sensitive region is measured using the scale, in a state in which a surface of the plate is focused.
11. The apparatus according to claim 1 , wherein letting S be a size of the sensitive region, L be a distance between a reverse surface of the plate and the sensitive region, L′ be a thickness of the plate, n be a refractive index of the plate, and NA be a numerical aperture of an illumination mode to be measured, the central mark is arranged in a region within a radius R represented by:
S/ 2−3·( L ·tan( a sin( NA ))+ L ′·tan( a sin( NA/n )))
from a center of the sensitive region.
12. An article manufacturing method comprising:
exposing a substrate by using an exposure apparatus according to claim 1 ; and
developing the substrate exposed in the exposing,
wherein an article is manufactured from the substrate developed in the developing.
13. The apparatus according to claim 1 , wherein the peripheral mark includes a mark formed as a repetitive pattern of openings and light shielding portions.
14. The apparatus according to claim 1 , wherein different measurement results are obtained in measurement using the central mark and measurement using the peripheral mark.
15. The apparatus according to claim 1 , wherein the central mark is arrange at a position closer to the center of the sensitive region than a position of the peripheral mark.