High-throughput, high-resolution, projection patterning system for large, flexible, roll-fed, electronic-module substrates

• US 5,652,645 A
• Filed: 07/24/1995
• Issued: 07/29/1997
• Est. Priority Date: 07/24/1995
• Status: Expired due to Term

• Current Assignee: Anvik Corporation
• Original Assignee: Anvik Corporation
• Inventors: Jain, Kanti
• Primary Examiner(s): Grimley, Arthur T.
• Assistant Examiner(s): KERNER, HERBERT
• Application Number:
  US08/506,232
• Time in Patent Office: 736 Days
• Field of Search: 355/53, 355/54, 355/64, 355/72, 355/73
• US Class Current: 355/53
• CPC Class Codes: G03F 7/2002 with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• 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
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/09972 Partitioned, e.g. portions of a PCB dedicated to different functions; Boundary lines therefore; Portions of a PCB being processed separately or differently
• CPC Class Codes: H05K 2203/1545 Continuous processing, i.e. involving rolls moving a band-like or solid carrier along a continuous production path
• CPC Class Codes: H05K 3/0082 characterised by the exposure method of radiation-sensitive masks
• CPC Class Codes: H05K 3/0097 Processing two or more printed circuits simultaneously, e.g. made from a common substrate, or temporarily stacked circuit boards H05K3/0052 takes precedence

Abstract

A projection imaging system is described for patterning large, flexible substrates at high exposure speeds and desired resolution, the substrates being in the form of a continuous band fed from a roller for cost-effective electronic module manufacturing. From the continuous band, segments of one panel size are sequentially exposed one at a time. The segment being exposed is held rigidly on a scanning stage, on which is also mounted a mask containing the pattern to be formed on the substrate. The imaging subsystem is stationary and situated above the scanning stage. The mask is illuminated with a hexagonal illumination beam and a region of similar shape is imaged on the substrate. The stage is programmed to scan the mask and substrate simultaneously across the hexagonal regions so as to pattern one whole panel. Provision is made for suitable overlap between the complementary intensity profiles produced by the hexagonal illumination, which ensures seamless joining of the scans and uniform patterning of an entire panel without image stitching errors. For handling the roll substrate so that the substrate segment being exposed remains held rigidly to the scanning stage while the stage moves it in two dimensions without damaging the integrity of the substrate band, mechanisms are provided in the projection system which include provision of managed slack lengths in the substrate band, controlled rotary motions of the supply and take-up substrate rollers, and synchronized, laterally sliding assemblies for the rollers.

Claims

1. A large-area, high-throughput, high-resolution, scan-and-repeat projection imaging system for replicating patterns present on a mask onto each of a sequence of segments (16) of a substrate band (10) characterized by

(a) a stage subsystem (18) comprising locking means for the mask (20) and locking means for a segment (16) of the substrate band (10) providing fixed juxtaposition of the mask (20) relative to the substrate band segment (16), said stage subsystem (18) being capable of scanning in one dimension, and when not scanning in that dimension, capable of moving laterally in a direction perpendicular to the scan direction so as to position itself for another scan;

said stage subsystem (18) thus being capable of exposing a full segment (16) of the substrate band (10) by breaking up the substrate band segment (16) area 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) an illumination subsystem (28-34) having the wavelength and intensity distribution characteristics suited for exposure of said substrate band (10), having an effective source plane of a predetermined shape, and capable of illuminating on said mask (20) a region of said predetermined shape;

(c) a projection subsystem (22-26) for imaging said illuminated region of said predetermined shape through the mask onto the substrate, having an object-to-image magnification ratio of substantially unity, having the desired imaging resolution, having means (26) to render the image in the same orientation as the object, and having an image field of said predetermined shape and of an area smaller than the substrate band (10) segment (16) area;

(d) means for sequentially presenting and affixing segments (16) of such substrate band (10) to said stage subsystem (18); and

(e) control means to operatively interrelate said stage subsystem (18), said substrate segment presenting means, said illumination subsystem (28-34) and said projection subsystem (22-26) to provide additive illumination in certain overlap regions of areas exposed by adjacent scans such that the effect of the exposure dose delivered in said overlap regions is seamless and the effect of the exposure dose delivered across the entire substrate band segment (16) is uniform.

2. A projection imaging system according to claim 1, further characterized in that

(a) said illumination subsystem (28-34) has an effective source plane in the shape of a regular hexagon, and illuminates a regular-hexagon-shaped region on said mask (20), and said regular-hexagon-shaped region on the mask is so oriented that two of its six sides are perpendicular to the scan direction;

and

(b) said projection subsystem (22-26) has an image field in the shape of a regular hexagon, and said regular-hexagon-shaped image field is so oriented that two of its six sides are perpendicular to the scan direction.

3. A projection imaging system according to claim 2, further characterized in that

the effective width, w, of each scan, as defined by the lateral separation between the center lines of two adjacent scans, is given by

4. A projection imaging system according to claim 1, further characterized in that

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

5. A projection imaging system according to claim 1, further characterized in that

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

6. A projection imaging system according to claim 1, further characterized in that

said stage subsystem (18) comprises a planar stage with a first position for said mask (20) and a second position for said substrate band segment (16), the two positions being aligned in the same plane for imaging by said projection subsystem (22-26).

7. A projection imaging system according to claim 1, further characterized in that

said stage subsystem (18) comprises a dual-platform stage with a first position on a first platform for said mask (20) and a second position on a second platform for said substrate band segment (16), the two positions being aligned in parallel planes for imaging by said projection subsystem (22-26).

8. A projection imaging system according to claim 1, further characterized in that

said stage subsystem substrate segment locking means comprises vacuum means (19) for holding a substrate segment (16) locked in place during exposure by multiple scans.

9. A projection imaging system according to claim 1, further characterized in that

said stage subsystem substrate segment locking means comprises a set of stage subsystem entry and stage subsystem exit platens (48,49) for holding a segment (16) of said substrate band (10) locked in place during exposure by multiple scans.

10. A projection imaging system according to claim 9, further characterized in that

said stage subsystem (18) entry and exit platens (48,49) have respective motors (60,61) to advance said substrate band (10), and the bottom surface of said substrate band (10) is against the surface of said stage subsystem (18).

11. A projection imaging system according to claim 1, further characterized in that

said stage subsystem substrate segment locking means comprises both a vacuum means (19) and a set of stage subsystem entry and stage subsystem exit platens (48,49) for holding a segment (16) of said substrate band (10) locked in place during exposure by multiple scans.

12. A projection imaging system according to claim 1, further characterized in that

said stage subsystem substrate locking means comprises a stage subsystem entry set and a stage subsystem exit set of pinch platens (48-49, 62-63) for holding a segment (16) of said substrate band (10) locked in place during exposure by multiple scans.

13. A projection imaging system according to claim 12, further characterized in that

said stage subsystem (18) entry and exit pinch platen sets (48,62/49,63) have respective entry and exit platen motors (60,61) to advance said substrate band (10).

14. A projection imaging system according to claim 1, further characterized in that

said stage subsystem substrate locking means comprises both a vacuum means (19) and a stage subsystem entry set and a stage subsystem exit set of pinch platens (48,49;

62,63) for holding a segment (16) of said substrate band (10) locked in place during exposure by multiple scans.

15. A projection imaging system according to claim 1, further characterized in that

said substrate presenting means and said control means provide stress relievers operating on said substrate band (10) on entry and exit sides of said stage subsystem (18) so that a substrate band (10) segment (16) remains locked in place on said stage subsystem (18) while being scanned along the longitudinal direction of the substrate band (10), whereby said substrate band (10) remains undamaged.

16. A projection imaging system according to claim 15, further characterized in that

said substrate presenting means comprises supply roller means (12) and take-up roller means (14) and said stress relievers are slack lengths (13,15/64,65) sufficient to permit scanning along the longitudinal direction of the substrate band (10) without disturbing the lock of substrate band (10) segment (16) to said stage subsystem (18) and without damage to said substrate band (10).

17. A projection imaging system according to claim 16, further characterized in that

said stress relieving slack lengths (13,15/64,65) are sufficient to permit scanning along the longitudinal direction of the substrate band (10) and stepping along the lateral direction without disturbing the lock of the substrate band segment (16) to said stage subsystem (18) and without damage to said substrate band (10).

18. A projection imaging system according to claim 17, further characterized in that

(a) said supply roller (12) and said take-up roller (14) have their axes along the same direction;

(b) said substrate band (10) makes two 90 degree turns in its path from said supply roller (12) to said stage subsystem (18) to said take-up roller (14);

(c) said control means controls delivery of said substrate band (10) to provide slack lengths in said two 90 degree turns, to accommodate both longitudinal motion and lateral motion of said stage subsystem (18); and

(d) said control means causes said rollers to rotate to release new substrate length from said supply roller (12) and take up exposed substrate length on said take-up roller (14).

19. A projection imaging system according to claim 18, further characterized in that

said control means causes said supply roller (12) and said take-up roller (14) to rotate oppositely.

20. A projection imaging system according to claim 18, wherein said stress-relieving slack length between said supply roller (12) and said stage subsystem (18) causes inversion of the plane of said substrate band (10) and said stress-relieving slack length between said stage subsystem (18) and said take-up roller (14) causes re-inversion of the plane of said substrate band (10).

21. A projection imaging system according to claim 18, further characterized in that

said substrate band (10) is wound from above on one of said supply roller (12) and said take-up roller (14) and from below on the other, and said control means causes said supply roller and said take-up roller to rotate in the same direction.

22. A projection imaging system according to claim 21, further characterized in that

said supply roller (12) and said take-up roller (14) are mounted on a common axle.

23. A projection imaging system according to claim 17, further characterized in that

said stress relievers comprise movable auxiliary rollers (70,72) to manage and guide the movement of said slack lengths (13,15/64,65) of said substrate band (10).

24. A projection imaging system according to claim 16, further characterized in that

said stress relievers include supply and take-up roller slides (40-45) and said control means controls said roller slides to match the lateral motion of said stage subsystem (18).

25. A projection imaging system according to claim 24, further characterized in that

said stress relievers include slack lengths (46,47) which are insufficient to permit scanning along the longitudinal direction of the substrate band (10) without damage to said substrate band (10) or stress to the locking of said substrate band (10) segment (16) to said stage subsystem (18), but include provision for rotary motions of said supply roller (12) and said take-up roller (14) stages (40-45) which are controlled to match within broad tolerances the motion of said stage subsystem (18) to provide the functions of preventing said damage and relieving said stress.

26. A projection imaging system according to claim 24, further characterized in that

said roller slides (40,41;

43,44) are air bearing stages with drive from linear motors (42,45).

27. A projection imaging system according to claim 24, further characterized in that

said roller slides (40,41:

43,44) are crossed roller-bearing stages.

28. A projection imaging system according to claim 24, further characterized in that

a) said supply and take-up rollers are controlled to turn simultaneously to accommodate longitudinal scanning of said stage subsystem (18);

b) said roller slides (40-45) are controlled to slide to accommodate lateral stepping of said stage subsystem (18); and

c) said stress relievers include small slack lengths (46,47) in the substrate band (10) to eliminate precision requirements for the roller turning movements.

29. A projection imaging system according to claim 1, further characterized in that

said stage subsystem (18) is fixed, and relative scanning motion of said illumination region of said predetermined shape on said mask (20) is carried out by movement of said illumination subsystem (28-34) and said projection subsystem (22-26).

30. The method of providing a high-throughput, high-resolution, projection patterning system for a large, flexible substrate, in the of a long band, for exposure of a series of panel-segments of such substrate, comprising the following steps:

(a) Providing a stage for holding in fixed juxtaposition both a panel-size segment of the substrate band and a mask, and capable of scanning longitudinally in one direction, and also capable of moving laterally in a direction perpendicular to the scan direction;

(b) Providing an illumination system having the wavelength and intensity distribution characteristics suited for exposure of said substrate, having an effective source plane of a predetermined shape, and capable of uniformly illuminating on said mask a region of said predetermined shape;

(c) Providing a projection assembly having an image field of said predetermined shape on said mask, which image field may be substantially smaller than the size of said panel-segment of the substrate band, and capable of producing a 1;

1 magnification image of said illuminated region of said predetermined shape of the mask onto the substrate segment with the required resolution;

(d) Providing an optical reversing unit which, in conjunction with the projection assembly of step (c), helps produce an image on the substrate segment that is in the same orientation as the object pattern on the mask;

(e) Providing rollers to supply and take up the flexible substrate band material and providing mechanisms to affix a panel-segment of the substrate on the stage so as to enable the stage to move both longitudinally and laterally without damaging any portion of the substrate band;

(f) Scanning the stage (a) so that the length of the mask traverses across the illumination region described in step (b);

(g) Stopping the stage momentarily after completion of a scan across the length of the mask, moving the stage by a certain distance in a direction perpendicular to the scan direction, and resuming the scanning of the stage in a direction opposite to the scan direction in step (f);

(h) Providing additive, complementary illumination in certain overlap regions of areas exposed by adjacent scans such that the effect of the exposure dose delivered in said overlap regions is seamless and the effect of the exposure dose delivered across the entire substrate is uniform;

(i) Repeating steps (f-h) until exposure of one entire panel-segment of the substrate is completed;

(j) Releasing the exposed panel-segment of the substrate from the stage, releasing an equal length of substrate from the supply roller, affixing another panel-segment of the substrate on the stage, winding up an equal length of substrate on the take-up roller, and repeating steps (f-i) above until exposure of the entire new panel-segment of the substrate is completed; and

(k) Repeating steps (f-j) above until exposure of the entire roll of substrate band material is completed.

31. The method of providing a projection imaging system according to claim 30, further characterized in that said illumination system has an effective source plane in the shape of a regular hexagon, and is capable of uniformly illuminating a regular-hexagon-shaped region on said mask.

32. A high-throughput, projection patterning system for a roller-to-roller transported substrate band (10) of semi-flexible substrate material for imaging of a longitudinally arranged sequence of substrate band segments (16), comprising:

(a) substrate segment imaging means comprising an x-y stage subsystem (18) and locking means to hold such a segment (16) of said semi-flexible substrate band (10) in a fixed imaging position with respect to a mask (20) and in a precisely and controllably variable position with respect to stationary imaging means;

(b) substrate supply means (12/40) for presenting such semi-flexible substrate band (10) to said imaging means;

(c) substrate take-up means (14/43) for accepting such semi-flexible substrate band (10) from said imaging means; and

(d) supply stress-relieving means intermediate said substrate supply means and said imaging means; and

(e) take-up stress-relieving means intermediate said imaging means and said substrate take-up means.

33. A high-throughput, projection patterning system according to claim 32, wherein said supply stress-relieving means is a slack length of said substrate band (10) that causes inversion of the plane of the substrate band (10) and said take-up stress relieving means is a slack length that causes re-inversion of the plane of the substrate band (10).

34. A high-throughput, projection patterning system according to claim 32, wherein said supply and take-up stress relieving means are controlled-motion mechanisms for moving the respectively related substrate supply means and substrate take-up means synchronously with movement of said stage subsystem (18).

35. A high-throughput, projection patterning system according to claim 32, wherein said supply and take-up stress relieving means comprise substrate slack length control mechanisms for keeping the related substrate supply means and substrate take-up means isolated from longitudinal and lateral movements of said imaging means.

36. A high-throughput, projection patterning system according to claim 35 wherein said supply stress relieving means and take-up stress relieving means include means for managing the isolation of the related substrate supply means and substrate take-up means from longitudinal and lateral movements of said imaging means.

37. A high-throughput, projection patterning system comprising

(a) means for feeding a substrate band (10) to present a substrate band segment (16) for imaging at a imaging station;

(b) locking means to affix said substrate band segment (16) and a mask (20) to said imaging station in a fixed mutual spatial relationship;

(c) an illumination subsystem for illuminating a polygonal region on said mask;

(d) a projection subsystem for imaging said illuminated polygonal mask region onto said substrate band segment;

(e) means for providing a sequence of scanning motions of said illumination subsystem and said projection subsystem, relative to said fixed mask (20) and said fixed substrate band segment (16);

whereby said substrate band segment (16) is exposed seamlessly and uniformly by a sequence of overlapping polygonal scans.