Apparatus for projection patterning of large substrates using limited-travel precision x-y stage

• US 6,201,597 B1
• Filed: 02/05/1999
• Issued: 03/13/2001
• Est. Priority Date: 05/28/1997
• Status: Expired due to Term

• Current Assignee: Anvik Corporation
• Original Assignee: Anvik Corporation
• Inventors: Dunn, Thomas J., Jain, Kanti, Farmiga, Nestor O.
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): LEROUX, ETIENNE PIERRE
• Application Number:
  US09/245,700
• Time in Patent Office: 767 Days
• Field of Search: 355/53, 355/55
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70475 Stitching, i.e. connecting image fields to produce a device field, the field occupied by a device such as a memory chip, processor chip, CCD, flat panel display
• CPC Class Codes: G03F 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70791 Large workpieces, e.g. glass substrates for flat panel displays or solar panels

Abstract

A large-format substrate patterning system, for microelectronics manufacturing, utilizes a substrate docking fixture to enable relative motion between the substrate stage and the substrate. This enables exposure of a large-format substrate which has been partitioned into different modules where each module contains an entire pattern transferred from a mask. This projection system enables patterning of a large multi-module substrate using a stage whose range of travel is smaller than the size of the substrate and using a mask whose area is smaller than the size of the substrate. This is accomplished by repositioning the substrate to expose each module sequentially In order to reposition the substrate, its location is maintained fixed in space by a substrate docking fixture while the movable stage of the lithography system is repositioned to position a different module of the substrate in the image field of the lithography tool. This allows the use of a mask whose size is determined by the size of each substrate module, and the use of a scanning stage whose required range of travel is determined by the size of the substrate module, and not by the size of the entire substrate. This eliminates the size limitation of the substrate from dependence on the range of travel of the stage, and permits the repetitive use of a small mask or series of small masks to produce a composite multi-module pattern on the substrate.

Claims

1. A large-area, high-throughput, high-resolution, scan-and-repeat, projection imaging system for replicating patterns present on a mask onto a substrate, which substrate includes a set of substrate modules each corresponding to the mask, including a currently selected substrate module and subsequently selected substrate modules,

characterized by:

(a) a scanning stage subsystem (12,16/12) capable of scanning the mask and the substrate in one dimension, and also being capable of moving laterally in a direction perpendicular to the scan direction so as to position itself for another scan;

said stage subsystem thus being capable of exposing each full substrate module by configuring each substrate module into a certain number of parallel strips, and exposing each of said strips by scanning the length of the strip across a fixed illumination region;

(b) a substrate holding platform (9), mounted on said stage subsystem (12), for affixing in predetermined relationship to said stage subsystem (12) a substrate (10/6) having a currently selected substrate module and subsequently selected substrate modules;

(c) mask holding means (13), mounted on said stage subsystem (12,16/12), for affixing a mask (20) in predetermined relationship to said stage subsystem (12,16/12);

(d) an illumination subsystem (18) having spectral and intensity characteristics suited for exposure of said substrate (10/6), having an effective source plane of a predetermined shape, and for uniformly illuminating on said mask (14) a region of said predetermined polygonal shape;

(e) a projection subsystem (26/25-27) capable of imaging said illuminated region on the mask onto said currently selected substrate module, and having an image field area smaller than the substrate module area;

(f) a substrate docking fixture (1) capable of temporarily gripping and immobilizing said substrate (10/6) while permitting relative movements between said substrate holding platform (9) and the substrate (10/6) so as to shift the location of the mask image from a currently selected module on said substrate to a subsequently selected substrate module; and

(g) control means (30) to operatively interrelate said scanning stage subsystem (12,16/12), said illumination subsystem (18), said substrate holding platform (9) and said substrate docking fixture (1) to provide additive illumination in certain overlap regions of areas exposed by adjacent strip scans of each substrate module such that the effect of the exposure dose delivered in said overlap regions is seamless and the effect of the exposure dose delivered across each entire substrate module is uniform.

2. A projection imaging system according to claim 1,

further characterized in that

said illumination subsystem (18) has an effective source plane in the shape of a regular hexagon.

3. A projection imaging system according to claim 1,

further characterized in that

said illumination subsystem (18) provides radiation from a mercury lamp.

4. A projection imaging system according to claim 1,

further characterized in that

said illumination subsystem (18) provides radiation from an excimer laser.

5. A projection imaging system according to claim 1,

further characterized in that:

said scanning stage subsystem capable of scanning the mask and the substrate is a single planar stage (12) on which is mounted a holding platform (9) on which are affixed the substrate (10/6) and the mask (14); and

said projection subsystem (26/25-27) has an imaging ratio which is substantially one-to-one.

6. A projection imaging system according to claim 1,

further characterized in that:

said substrate holding platform (9) is capable of holding one panel-section of a substrate that is flexible and continuous.

7. A projection imaging system according to claim 1,

further characterized in that:

said substrate docking fixture (1) serves also as an automated substrate handling system.

8. A projection imaging system according to claim 1,

further characterized in that:

said substrate docking fixture (1) is movable in the three dimensions x, y and z.

9. A projection imaging system according to claim 1,

further characterized in that:

said substrate docking fixture (1) is movable in the three dimensions x, y and z and serves as an automated substrate handling system.

10. A projection imaging system according to claim 1,

further characterized in that:

said substrate docking fixture (1) is capable of gripping and immobilizing the substrate (10/6) in a single, fixed positional relationship with respect to the substrate docking fixture (1).

11. A projection imaging system according to claim 1,

further characterized in that:

said substrate docking fixture (1) is capable of gripping and immobilizing the substrate (10/6) in multiple, selectable positional relationships with respect to the substrate docking fixture (1).

12. A projection imaging system according to claim 1,

further characterized in that:

said scanning stage subsystem capable of scanning the mask and the substrate comprises two separate stages, a mask scanning stage (16) on which is mounted the mask (14) affixed in its holder (13), and a substrate scanning stage (12) on which is mounted the substrate (10) affixed in its holder (9).

13. A projection imaging system according to claim 12,

further characterized in that:

said projection subsystem (26) has an imaging ratio which is substantially one-to-one; and

said control means (30) causes said mask scanning stage (16) and said substrate scanning stage (12) to move with substantially equal velocities.

14. A projection imaging system according to claim 12,

further characterized in that:

said projection subsystem (26) has an imaging ratio which is substantially N-to-one, N being a number other than 1; and

said control means (30) causes said mask scanning stage (16) and said substrate scanning stage (12) to move with velocities with ratio N-to-one.

25. A precision imaging system according to claim 1,

further characterized in that:

said scanning stage subsystem capable of scanning the mask and the substrate comprises two separate stages, a mask scanning stage (16) on which is mounted the mask (14) to its holder (9), said holder (9) being significantly larger than the supporting means of said stage subsystem (12).

15. A high-throughput, high-resolution, projection imaging system for replicating patterns present on a mask onto a substrate which includes a set of substrate modules each corresponding to the mask, which are to be subjected to a patterning image at an image field in which the projection optics project an effectively focused mask image onto at least a portion of a currently selected substrate module;

characterized by;

(a) a substrate holding platform (9) on a precision stage (12) which provides x and y motion to the substrate (10/6), with respect to the projection optics which ha s an imaging position, for scanning the mask image on the substrate, during an operational period of time in which the substrate is locked to said substrate holding platform (9) with a currently selected module of said substrate at said imaging position of said projection optics; and

(b) a substrate docking fixture (1) for temporarily immobilizing said substrate to permit relative movements between said substrate holding platform (9) and the substrate (10/6), during a relocation period of time in which the substrate is temporarily unlocked from said substrate holding platform (9), so as to shift the relative location of the substrate (10/6) from a currently selected module at the imaging position of said projection optics of said substrate to a subsequently selected substrate module at the imaging position of said projection optics.

16. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate docking fixture (1) comprises a vacuum chuck (2).

17. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate docking fixture (1) comprises a set (2) of vacuum fingers.

18. A high-throughput, high-resolution, projection imaging system according to claim 17,

further characterized in that:

said substrate docking fixture (1) comprises a set (2) of vacuum fingers with linear translational capability so as to be movable with respect to said substrate (10/6) in such fashion a that it always grips said substrate at selected contact points.

19. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate is in the form of a continuous web feeding from a supply position to a take-up position via the imaging position; and

said substrate docking fixture comprises a set (2) of substrate grippers at opposite sides of the imaging position, to immobilize said substrate temporarily while said substrate holding platform (9) is moved with respect to said substrate, in such fashion that the substrate is repositioned from the currently selected substrate module at the imaging position to the subsequently selected module at the imaging position.

20. A high-throughput, high-resolution, projection imaging system according to claim 19,

further characterized in that:

said substrate docking fixture comprises a set (2) of substrate grippers, at opposite sides of the imaging position, in the vicinities respectively of supply position and take-up position, to immobilize said substrate temporarily while said substrate holding platform (9) is moved with respect to said substrate, in such fashion that the substrate holding platform (9) on said substrate stage (12) serves both as a substrate feed device and as a substrate scanning motion device.

21. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate docking fixture (1) comprises means to reposition the substrate temporarily out of the way of said substrate holding platform (9) and the projection optics.

22. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate docking fixture (1) comprises selectively positionable substrate edge stop pins to stop substrate motion at a predetermined position to allow the substrate holding platform (9) to move to a predetermined relative position while the substrate is docked.

23. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized in that:

said substrate holding platform (9) is equipped with selectively activatable vacuum means and with selectively activatable air bearing pressure means for selectively locking said substrate and unlocking said substrate.

24. A high-throughput, high-resolution, projection imaging system according to claim 15,

further characterized by:

control means (30) to establish time durations and operational controls for said substrate docking fixture (1) for each of the following three operating modes;

Loading Mode, in which said substrate docking fixture (1) supplies substrate to said substrate holding platform (9) with a first currently selected substrate module in position at the imaging position;

Processing Mode, in which said substrate docking fixture (1) is non-operational while said substrate holding platform (9), with a first currently selected substrate module in position at the imaging position, locks onto the substrate for processing; and

Repositioning Mode, in which said substrate docking fixture (1) is operational to immobilize the substrate while said substrate holding platform (9) unlocks from the substrate and supplies a repositioning motion of said holding platform (9) with respect to the substrate;

whereby a stage with a relatively small travel range may be used to process a substrate area larger than the travel range of the stage, one module at a time, using the motion capability of the scanning stage itself to accomplish repositioning from a currently selected substrate module to a subsequently selected substrate module with the assistance of the substrate docking fixture.