Position detecting method, position detecting apparatus, exposure method, exposure apparatus, making method thereof, and device and device manufacturing method
In order to find the positional relation between the reference coordinate system XY which defines the movement of a substrate W and the arrangement coordinate system αβ which corresponds to a plurality of divided areas on the substrate W divided by street lines Sα and Sβ, the substrate W and an observation field are moved relatively. By allowing position detecting method marks Mk on the substrate W to visit the observation field, the street lines Sα and Sβ are detected in the observation field during the observation field. According to the results of the detection, an approximate arrangement coordinate system is corrected. The positional relation between the reference coordinate system XY and the arrangement coordinate system αβ is caught with high accuracy enough to allow the observation field to visit the position detection mark (Mk). Thus, by obtaining the arrangement coordinate system of the divided area in high speed with high accuracy, the highly precise exposure might be performed with improved throughput.
1. A position detecting method for detecting positions of a plurality of divided areas divided by street lines on the substrate, by using an observation optical system, said position detecting method comprising:
performing image pickup of a boundary between at least one said street lines and at least one of said divided areas on said substrate, while relatively moving said substrate and an observation field of said observation optical system in a direction perpendicular to an optical axis direction of the observation optical system;
detecting a positional change of said boundary in a different direction from a direction of said relative movement, based on image information obtained in said image pickup during the relative movement; and
detecting a positional relation between a reference coordinate system that defines a movement of said substrate, and an arrangement coordinate system that corresponds to an arrangement of said plurality of divided areas on the substrate, based on the detected positional change of said boundary.
2. The position detecting method according to claim 1 , wherein
in said performing image pickup, said image pickup of said boundary is performed at regular intervals during said relative movement.
3. The position detecting method according to claim 1 , wherein
said positional change of said boundary is detected in a direction substantially perpendicular to a direction of said relative movement in a two-dimensional plane including the direction of the relative movement.
4. The position detecting method according to claim 3 , wherein
the detection of said positional change of said boundary is performed during said relative movement.
5. The position detecting method according to claim 3 , wherein
said positional relation is detected, based on a positional change of said at least one of said street lines in a direction perpendicular to the direction of said relative movement while the relative movement is performed.
6. The position detecting method according to claim 5 , wherein
prior to the detection of said at least one of said street lines, an outer edge of said substrate is measured, and
based on the measurement result, said positional relation between said reference coordinate system and said arrangement coordinate system is detected with predetermined accuracy lower than accuracy with which the positional relation is detected while the relative movement is performed.
7. The position detecting method according to claim 6 , wherein
said substrate is rotated so that an axis direction of said reference coordinate system is parallel to an axis direction of said arrangement coordinate system, based on said positional relation detected with said predetermined accuracy.
8. The position detecting method according to claim 5 , wherein
said observation field is relatively moved with respect to said substrate along said at least one of said street lines.
9. The position detecting method according to claim 8 , wherein
in the detection of said at least one of said street lines, a positional change of a border between said at least one of said divided areas and said at least one of said street lines within said observation field is measured by observing a moving picture within said observation field while relatively moving said substrate and the observation field, and
said positional relation is detected based on the measurement result of the positional change of said border.
10. The position detecting method according to claim 9 , wherein
when it is presumed that said border is out of range of said observation field, the relative movement of said substrate and said observation field is corrected so that the border is continuously caught within the observation field.
11. The position detecting method according to claim 9 , wherein
in the detection of said at least one of said street lines, an image formed by a total quantity of light that reaches each point within said observation field is picked up during a predetermined pickup time, and
said positional change of said border within the observation field is measured based on the pickup result.
12. The position detecting method according to claim 1 , wherein
said positional change of said boundary is detected by obtaining image information through picking up an image of said boundary.
13. The position detecting method according to claim 1 , wherein
said relative movement of said substrate and said observation field is performed so that a predetermined number of position detection marks, which are chosen from a plurality of position detection marks formed on said at least one of said street lines, are caught within the observation field in predetermined order,
a position of the chosen predetermined number of position detection mark is detected, and
based on the detection result, said positional relation is detected with higher accuracy than accuracy with which the positional relation is detected while the relative movement is performed.
14. A position detecting apparatus that detects positions of a plurality of divided areas divided by street lines on a substrate, said position detecting apparatus comprising:
a substrate stage that holds said substrate;
an observation system that performs image pickup of said substrate by using an observation optical system;
a driving unit that drives said substrate stage in a direction perpendicular to an optical axis direction of said observation optical system; and
a processing unit that is electrically connected to the observation system, and obtains a positional relation between a reference coordinate system that defines a movement of the substrate stage, and an arrangement coordinate system that corresponds to an arrangement of said plurality of divided areas on the substrate, based on image information regarding a boundary between at least one of said street lines and at least one of said divided areas obtained by the observation system while the substrate stage is moved by said driving unit.
15. The position detecting apparatus according to claim 14 , wherein
said observation system observes a positional change of said boundary in a direction substantially perpendicular to a moving direction of said substrate stage during the movement of said substrate stage.
16. The position detecting apparatus according to claim 15 , further comprising:
a control system that is electrically connected to said driving unit, and controls the driving unit so that said at least one of said street lines is detected by said observation system while moving said substrate stage, when detecting a mark on said substrate.
17. The position detecting apparatus according to claim 16 , wherein
said control system controls said driving unit so that said observation field of said observation system follows a route to a predetermined position detection mark that is chosen from the position detection marks formed on said at least one of said street lines, and
the control system further detects a position of the chosen predetermined position detection mark and detects a position of each divided area based on the detection result of the chosen predetermined position detection mark.
18. The position detecting apparatus according to claim 17 , wherein
said route is along a street line.
19. The position detecting apparatus according to claim 14 , wherein
said observation system comprises an image pickup apparatus that obtains image information by performing image pickup of a substrate surface.
20. An exposure method in which a predetermined pattern is transferred to a divided area on a substrate by emitting an energy beam, said exposure method comprising:
detecting a position of said divided area formed on said substrate by using the position detecting method according to claim 1 , prior to said transfer.
21. An exposure apparatus that transfers a predetermined pattern to a divided area on a substrate by emitting an energy beam, said exposure apparatus comprising:
an illumination system that emits said energy beam; and
the position detecting apparatus according to claim 14 that detects a position of said at least one of said divided areas.
22. A making method of a position detecting apparatus that detects a plurality of divided areas divided by street lines on a substrate, said method comprising:
providing a substrate stage that holds said substrate;
providing an observation system that performs image pickup of said substrate by using an observation optical system;
providing a driving unit that drives said substrate stage in a direction perpendicular to an optical axis direction of said observation optical system; and
providing a processing unit that is electrically connected to the observation system, and obtains a positional relation between a reference coordinate system that defines a movement of the substrate stage, and an arrangement coordinate system that corresponds to an arrangement of said plurality of divided areas on the substrate, based on image information regarding a boundary between at least one of said street lines and at least one of said divided areas obtained by said observation system while the substrate stage is moved by said driving unit.
23. A device manufacturing method comprising a lithographic process, wherein
a predetermined pattern is transferred onto a divided area divided by street lines on said substrate, by using the exposure method according to claim 20 .
24. A device manufactured by using the device manufacturing method according to claim 23 .
25. The position detecting method according to claim 1 , wherein:
based on said detected positional relation between said reference coordinate system and said arrangement coordinate system, a direction of the relative movement is changed while relatively moving said substrate and said observation field.