EXPOSURE APPARATUS AND AN EXPOSURE METHOD

• US 20040032575A1
• Filed: 12/21/2001
• Published: 02/19/2004
• Est. Priority Date: 11/28/1996
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nishi, Kenji, Ota, Kazuya
• Granted Patent: US 6,798,491 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70216 Mask projection systems
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70733 Handling masks and workpieces, e.g. exchange of workpiece or mask, transport of workpiece or mask
• CPC Class Codes: G03F 9/70 for microlithography measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775
• CPC Class Codes: G03F 9/7003 Alignment type or strategy, e.g. leveling, global alignment
• CPC Class Codes: G03F 9/7015 Reference, i.e. alignment of original or workpiece with respect to a reference not on the original or workpiece
• CPC Class Codes: G03F 9/7026 Focusing
• CPC Class Codes: G03F 9/7088 Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection

Abstract

Two stages WS1, WS2 holding wafers can independently move between a positional information measuring section PIS under an alignment system 24a and an exposing section EPS under a projection optical system PL. The wafer exchange and alignment are performed on the stage WS1, during which wafer W2 is exposed on the stage WS2. A position of each shot area of wafer WS1 is obtained as a relative position with respect to a reference mark formed on the stage WS1 in the section PIS. Relative positional information can be used for the alignment with respect to an exposure pattern when the wafer WS1 is moved to the section EPS to be exposed. Therefore, it is not necessary that a stage position is observed continuously in moving the stage. Exposure operations are performed in parallel by the two wafer stages WS1 and WS2 so as to improve the throughput.

Claims

1. A lithographic device comprising:

a base surface extending parallel to an X-direction and parallel to a Y-direction;

first and second object holders each of which is moved over said base surface and is displaceable parallel to the X-direction and parallel to the Y-direction from a first position into a third position, the first position being included in an exposure section; and

a displacement system that displaces the first object holder and the second object holder over the base surface, wherein the displacement system includes a first displacement unit and a second displacement unit to which the first object holder and the second object holder can be coupled alternately, the first displacement unit displacing the object holders between the third position and a second position which is located between the first position and the third position, and displacing the object holders from the second position to the third position, and the second displacement unit displacing the object holders between the second position and the first position, and displacing the object holders from the first position to the second position.

2. A lithographic device according to claim 1, wherein each of the first and second displacement units includes a robot arm system.

3. A lithographic device according to claim 1, further comprising:

a first interferometer system which monitors the first object holder in the exposure section.

4. A lithographic device according to claim 3, wherein said first interferometer system monitors a position of the first object holder in the X-direction and in the Y-direction.

5. A lithographic device according to claim 4, wherein said first interferometer system monitors a yaw of the first object holder.

6. A lithographic device according to claim 4, wherein said first interferometer system monitors a pitch of the first object holder.

7. A lithographic device according to claim 3, further comprising:

a second interferometer system which monitors the second object holder outside the exposure section.

8. A lithographic device according to claim 7, wherein said second interferometer monitors the second object holder during a measuring operation for an object held by the second object holder.

9. A lithographic device according to claim 8, wherein in said measuring operation, alignment marks of the object on the second object holder are detected.

10. A lithographic device according to claim 4, wherein each of the object holders has a reflecting surface for the interferometer system.

11. A lithographic device according to claim 10, further comprising:

a reference mark provided on each of the object holders; and

a detecting system which detects the reference mark on the first object holder displaced in the exposure section, a plurality of shot areas on an object held by the first object holder being respectively positioned in place to be exposed, on the basis of information obtained by detecting the reference mark.

12. An exposure method comprising:

displacing a first object holder from a third area to a second area by using a first displacement unit, the first object holder being displaceable parallel to an X-direction and parallel to a Y-direction;

displacing a second object holder from a first area to the second area by using a second displacement unit, the second object holder being displaceable parallel to the X-direction and parallel to the Y-direction, and the second area being between the first area and the third area;

displacing the first object holder from the second area to the first area by using the second displacement unit, the first object holder and the second object holder being alternately coupled to the second displacement unit;

displacing the second object holder from the second area to the third area by using the first displacement unit, the first object holder and the second object holder being alternately coupled to the first displacement unit; and

wherein after completion of an exposure operation for a second object on the second object holder in the first area, the second object is moved from the first area to the third area via the second area, and then a first object to be exposed on the first object holder is transferred from the third area to the first area via the second area.

13. An exposure method according to claim 12, further comprising:

during said exposure operation, performing a measuring operation for the first object on the first object holder.

14. An exposure method according to claim 13, wherein in the measuring operation, alignment marks formed on the first object are detected.

15. An exposure method according to claim 12, further comprising, during said exposure operation, performing an object exchange operation in the third area in which the first object is exchanged on the first object holder with a third object.

16. An exposure method according to claim 12, further comprising, during said exposure operation, monitoring the second object holder by using an interferometer system.

17. An exposure method according to claim 16, wherein said interferometer system can monitor a yaw, a pitch and positions in the X-direction and the Y-direction of the second object holder.

18. An exposure method according to claim 16, further comprising, before an exposure operation for the first object on the first object holder, beginning to monitor the first object holder which has been displaced into the first area by using said interferometer system.

19. An exposure method according to claim 18, further comprising:

detecting a reference mark provided on the first object holder displaced into the first area; and

after the detection of the reference mark, performing the exposure operation for the first object on the first object holder, wherein a plurality of shot areas of the first object on the first object holder are respectively positioned in place to be exposed, on the basis of information obtained by the detection of the reference mark.

20. A microdevice manufacturing method using the exposure method as defined in claim 12.