Position correction in Y of mask object shift due to Z offset and non-perpendicular illumination
In a reflective lithographic projection apparatus, shifts in the image of a pattern of a mask in the scanning direction caused by variations in the position of the pattern surface of the mask along the optical axis are corrected by shifting of the relative position of the mask and/or the substrate in the scanning direction. Correction of the image rotation error may also be accomplished by rotation of the relative positions of the mask and/or the substrate about the optical axis. Variations in the position of the pattern surface of the mask along the optical axis may be determined by interferometers upon installation of the mask to the lithographic projection apparatus. The variations may be mapped and stored to provide control of the lithographic projection apparatus.
1. A lithographic projection apparatus, comprising:
a radiation system constructed and arranged to provide a bean of radiation;
a support structure constructed and arranged to support a reflective patterning device, the patterning device including a pattern surface and constructed and arranged to pattern the beam of radiation according to a desired pattern;
a substrate table to hold a substrate; and
a projection system constructed and arranged to project the patterned beam onto a target portion of the substrate, wherein the support structure and the substrate table are movable with respect to each other in a first direction and during movement of the support structure and the substrate table with respect to each other a variation in a position of the pattern surface in a second direction perpendicular to the first direction is corrected by at least one of adjusting a position of the patterning device in the first direction, adjusting a position of the substrate in the first direction, rotating the substrate about an axis parallel to the second direction, and rotating the patterning device about the axis parallel to the second direction.
2. An apparatus according to claim 1 , further comprising an interferometer system constructed and arranged to determine the variation of the position of the pattern surface in the second direction.
3. An apparatus according to claim 2 , wherein the interferometer system includes two interferometers that determine the position of the pattern surface with respect to the projection system.
4. An apparatus according to claim 2 , wherein the interferometer system determines the variation of the position of the pattern surface in the second direction by measuring the position of tracks of the patterning device outside the pattern surface.
5. An apparatus according to claim 1 , wherein the positions of the patterning device and the substrate are adjusted relative to each other during movement of the support structure and the substrate table with respect to each other in the first direction by an amount ΔY=ΔZ·tan α, where ΔZ is the variation of the position of the pattern surface in the second direction and α is an angle of incidence of the projection beam on the patterning device.
6. An apparatus according to claim 5 , wherein adjusting the positions of the patterning device and the substrate relative to each other includes adjusting a velocity of the patterning device and the substrate with respect to each other during movement of the patterning device and the substrate relative to each other.
7. An apparatus according to claim 1 , wherein rotating the substrate about the axis parallel to the second direction includes rotating the substrate by an amount Δθ 2w =+/−tan α·(ΔZ2−ΔZ1)/d, wherein α is the angle of incidence of the projection beam on the patterning device, ΔZ1 is a first measured variation in a position of the pattern surface in the second direction, ΔZ2 is a second measured variation in a position of the pattern surface in the second direction, and d is a distance between two measurement positions of ΔZ1 and ΔZ2 in a third direction perpendicular to the first and second directions.
8. An apparatus according to claim 1 , wherein a velocity of the support structure and a velocity of the substrate table are adjustable with respect to each other during movement of the support structure and the substrate table with respect to each other.
9. A met of transferring a pattern formed on a reflective patterning device including a pattern surface onto a substrate coated with a radiation sensitive material, comprising:
projecting a beam of radiation incident on the patterning device at a predetermined angle through a projection system while synchronously moving the patterning device, the substrate and a mirror of the projection system in a first direction;
determining variations in a position of the pattern surface in a second direction perpendicular to the first direction; and
during synchronous movement the patterning device, the substrate and the mirror, adjusting at least one of a position of the patterning device in the first direction, adjusting a position of the substrate in the first direction, adjusting a position of the mirror in the first direction, and rotating the substrate about an axis parallel to the second direction to connect the variations in the position of the pattern from a focal plane.
10. A method according to claim 9 , wherein determining the variations in the position of the pattern surface includes determining a position of the patterning device with respect to the projection system.
11. A method according to claim 9 , wherein adjusting the positions of the patterning device, the substrate and the mirror relative to each other in the first direction includes adjusting the relative positions by an amount ΔY=ΔZ·tan α, where ΔZ is an amount of the variation of the pattern from the focal plane and α is the angle of incidence of the beam of radiation on the pattering device.
12. A method according to claim 11 , wherein adjusting the positions of the patterning device, the substrate and the mirror relative to each other includes adjusting a velocity of at least one of the patterning device, the wafer and the mirror with respect to each other during movement of the patterning device, the substrate, and the mirror relative to each other.
13. A method according to claim 9 , wherein rotating the substrate about the axis includes rotating the substrate by an amount Δθz=+/−tan α·(ΔZ2−ΔZ1)/d, wherein α is the angle of incidence of the projection beam on the patterning device, ΔZ1 is a first measured variation of the pattern surface in the second direction, ΔZ2 is a second measured variation of the pattern surface in the second direction, and d is a distance between two displacement measuring devices in a third direction perpendicular to the first and second directions.
14. A method according to claim 9 , wherein determining variations in the position of the pattern surface in the second direction includes determining variations of a position of the pattern surface in the second direction by measuring the position of tracks of the patterning device outside the pattern surface.
15. A method according to claim 9 , further comprising adjusting a velocity of the patterning device, a velocity of the substrate, and a velocity of the mirror with respect to each other during synchronous movement of the patterning device, the substrate, and the mirror.
16. A device manufacturing method, comprising:
providing a substrate that is at least partially covered by a layer of radiation sensitive material;
providing a beam of radiation using a radiation system;
using a pattering device to endow the projection beam with a pattern in its cross-section;
projecting the patterned beam of radiation onto a target portion of the layer of radiation sensitive material using a projection system including a mirror;
synchronously moving the substrate, the patterning device and the mirror with respect to each other in a first direction; and
at least one of adjusting a position of the patterning device in the first direction, adjusting a position of the substrate in the first direction, adjusting a position of the mirror in the first direction, and rotating the substrate table about an axis parallel to a second direction perpendicular to the first direction during synchronous movement of the substrate, the patterning device and the mirror with respect to each other.
17. A method according to claim 16 , further comprising adjusting a velocity of the patterning device, a velocity of the substrate, and a velocity of the mirror with respect to each other during synchronous movement of the patterning device the substrate and the mirror with respect to each other.
18. A lithographic projection apparatus, comprising:
a radiation system constructed and arranged to provide a projection beam of radiation;
a support structure constructed and arranged to support a reflective patterning device, the patterning device including a pattern surface and constructed and arranged to pattern the projection beam according to a desired pattern;
a substrate table to hold a substrate; and
a projection system constructed and arranged to project the patterned beam onto a target portion of the substrate, the projection system including a mirror, wherein the support structure the substrate table and the mirror are each movable with respect to each other in a first direction and variations in a position of the pattern surface in a second direction perpendicular to the first direction are corrected by at least one of adjusting a position of the patterning device in the first direction, adjusting a position of the substrate in the first direction, adjusting a position of the mirror in at least one of six degrees of freedom, rotating the substrate about an axis parallel to the second direction, and rotating the patterning device about the axis parallel to the second direction.
19. A apparatus according to claim 18 , wherein the variations in the pattern surface in the second direction are determined by measuring variations of positions of tracks of the patterning device outside the pattern surface.
20. An apparatus according to claim 18 , wherein a velocity of the support structure, a velocity of the substrate table, and a velocity of the mirror adjustable with respect to each other during movement of the support structure, the substrate table, and mirror with respect to each other.