Methods for fabricating microstructures by imaging a radiation sensitive layer sandwiched between outer layers

• US 7,192,692 B2
• Filed: 09/11/2003
• Issued: 03/20/2007
• Est. Priority Date: 09/11/2003
• Status: Active Grant

• Current Assignee: Bright View Technologies Corporation (Tredegar Corporation)
• Original Assignee: Bright View Technologies, Inc. (Tredegar Corporation)
• Inventors: Wood, Robert L., Freese, Robert P., Rinehart, Thomas A.
• Primary Examiner(s): McPherson; John A.
• Application Number:
  US10/661,974
• Publication Number:
  US 20050058949A1
• Time in Patent Office: 1,286 Days
• Field of Search: None
• US Class Current: 430/320
• CPC Class Codes: G02B 3/0025 Machining, e.g. grinding, polishing, diamond turning, manufacturing of mould parts
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 5/1852 using mechanical means, e.g. ruling with diamond tool, moulding
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G03F 7/0005 Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor
• CPC Class Codes: G03F 7/0015 Production of aperture devices, microporous systems or stamps
• CPC Class Codes: G03F 7/161 using a previously coated surface, e.g. by stamping or by transfer lamination
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

Microstructures are fabricated by imaging a microstructure master blank that includes a radiation sensitive layer sandwiched between a pair of outer layers, on an imaging platform, to define the microstructures in the radiation sensitive layer. At least one of the outer layers is then removed. The microstructures that were defined in the radiation sensitive layer are developed. The radiation sensitive layer sandwiched between the pair of outer layers may be fabricated as webs, to provide microstructure master blanks.

Claims

1. A method of fabricating microstructures comprising:

imaging a microstructure master blank that comprises a radiation sensitive layer sandwiched between a pair of outer layers, on an imaging platform, to define the microstructures in the radiation sensitive layer, the pair of outer layers comprising a first outer layer adjacent the imaging platform and a second outer layer remote from the imaging platform;

removing the second outer layer from the radiation sensitive layer;

developing the microstructures that were defined in the radiation sensitive layer; and

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by contacting the microstructures to a stamper blank.

2. A method according to claim 1 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by pressing the microstructures against a stamper blank.

3. A method according to claim 1 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by rolling the microstructures against a stamper blank.

4. A method according to claim 1 wherein contacting the microstructures to a stamper blank is performed while the radiation sensitive layer and the first outer layer remain on the imaging platform.

5. A method according to claim 1 wherein imaging is preceded by:

placing the radiation sensitive layer sandwiched between a pair of outer layers on the imaging platform.

6. A method according to claim 1 wherein the radiation sensitive layer is at least about one square foot in area.

7. A method according to claim 1 wherein imaging is performed continuously on the radiation sensitive layer for at least about 1 hour.

8. A method according to claim 1 wherein imaging is performed continuously on the radiation sensitive layer for at least about 1 hour to fabricate at least about one million microstructures.

9. A method according to claim 1 wherein the microstructures comprise optical and/or mechanical microstructures.

10. A method according to claim 1 wherein developing comprises developing the microstructures that were defined in the radiation sensitive layer to provide a microstructure master.

11. A method according to claim 1 wherein the pair of outer layers are cylindrical, ellipsoidal or polygonal in shape.

12. A method according to claim 1 wherein the imaging comprises impinging a radiation beam through the second outer layer into the radiation sensitive layer to define microstructures in the radiation sensitive layer.

13. A method according to claim 1 wherein the radiation sensitive layer is a negative photoresist layer such that portions of the negative photoresist layer that are exposed to the radiation beam remain after development.

14. A method according to claim 1 wherein the pair of outer layers are flexible.

15. A method of fabricating microstructures comprising:

imaging a microstructure master blank that comprises a radiation sensitive layer sandwiched between a pair of outer layers, on an imaging platform, to define the microstructures in the radiation sensitive layer, the pair of outer layers comprising a first outer layer adjacent the imaging platform and a second outer layer remote from the imaging platform;

separating the first outer layer from the imaging platform; and

separating the first or second outer layer from the radiation sensitive layer;

developing the microstructures that were defined in the radiation sensitive layer; and

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by contacting the microstructures to a stamper blank.

16. A method according to claim 15 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by pressing the microstructures against a stamper blank.

17. A method according to claim 15 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the radiation sensitive layer by rolling microstructures against a stamper blank.

18. A method according to claim 15 wherein the microstructures comprise optical and/or mechanical microstructures.

19. A method of fabricating microstructures comprising:

imaging a first microstructure master blank that comprises a radiation sensitive layer sandwiched between a pair of outer layers, on an imaging platform, to define the microstructures in the radiation sensitive layer,

removing at least one of the outer layers;

creating a second generation stamper by developing the microstructures in the first microstructure master blank and contacting the microstructures to a stamper blank; and

imaging a second microstructure master blank that comprises a radiation sensitive layer sandwiched between a pair of outer layers, on the imaging platform, to define second microstructures in the radiation sensitive layer;

wherein imaging a second microstructure master blank and creating a second-generation stamper at least partially overlap in time.

20. A method according to claim 19 wherein the microstructures comprise optical and/or mechanical microstructures.

21. A method of fabricating microstructures comprising:

imaging a first microstructure master blank that comprises a radiation sensitive layer sandwiched between a pair of outer layers, on an imaging platform, to define the microstructures in the radiation sensitive layer,

removing at least one of the outer layers;

developing the microstructures that were defined in the radiation sensitive layer to provide a microstructure master;

forming a plurality of second generation stampers directly from the master; and

forming a plurality of third generation microstructure end products directly from a stamper.

22. A method according to claim 21 wherein the microstructures comprise optical and/or mechanical microstructures.

23. A method of fabricating a microstructure master comprising:

placing on a cylindrical platform, a microstructure master blank that comprises a first outer layer, a negative photoresist layer on the first outer layer and a second outer layer on the negative photoresist layer, such that the first outer layer is adjacent the cylindrical platform and the second outer layer is remote from the cylindrical platform;

impinging a laser beam through the second outer layer into the negative photoresist layer while simultaneously rotating the cylindrical platform about an axis thereof and while simultaneously axially rastering the laser beam across at least a portion of the negative photoresist layer to image the microstructures in the negative photoresist layer;

separating the first outer layer from the cylindrical platform;

separating the first outer layer from the negative photoresist layer;

developing the microstructures that were imaged in the negative photoresist layer; and

creating a second-generation stamper from the microstructures that were developed in the negative photoresist layer by contacting the microstructures to a stamper blank.

24. A method according to claim 23 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the negative photoresist layer by pressing the microstructures against a stamper blank.

25. A method according to claim 23 wherein creating comprises:

creating a second-generation stamper from the microstructures that were developed in the negative photoresist layer by rolling the microstructures against a stamper blank.

26. A method according to claim 23 wherein the microstructure master blank is at least about one square foot in area.

27. A method according to claim 26 wherein impinging is performed continuously on the microstructure master blank for at least about 1 hour.

28. A method according to claim 27 wherein impinging is performed continuously on the microstructure master blank for at least about 1 hour to fabricate at least about one million microstructures.

29. A method according to claim 23 wherein the microstructures comprise optical and/or mechanical microstructures.

30. A method according to claim 23 wherein the first and second outer layers are flexible.

31. A method of fabricating a microstructure master comprising:

placing on a cylindrical platform, a first microstructure master blank that comprises a first outer layer, a negative photoresist layer on the first outer layer and a second outer layer on the negative photoresist layer, such that the first outer layer is adjacent the cylindrical platform and the second outer layer is remote from the cylindrical platform;

impinging a laser beam through the second outer layer into the negative photoresist layer while simultaneously rotating the cylindrical platform about an axis thereof and while simultaneously axially rastering the laser beam across at least a portion of the negative photoresist layer to image the microstructures in the negative photoresist layer;

separating the first outer layer from the cylindrical platform;

separating the first outer layer from the negative photoresist layer; and

developing the microstructures that were imaged in the negative photoresist layer;

wherein separating the first outer layer from the cylindrical platform is followed by;

creating a second generation stamper from the microstructures that were developed in the negative photoresist layer of the first microstructure master blank by contacting the microstructures to a stamper blank;

placing on the cylindrical platform, a second microstructure master blank that comprises a first outer layer, a negative photoresist layer on the first outer layer and a second outer layer on the negative photoresist layer, such that the first outer layer is adjacent the cylindrical platform and the second outer layer is remote from the cylindrical platform;

impinging the laser beam through the second outer layer of the second microstructure master blank into the negative photoresist layer of the second microstructure master blank while simultaneously rotating the cylindrical platform about an axis thereof and while simultaneously axially rastering the laser beam across at least a portion of the negative photoresist layer of the second microstructure master blank to image the microstructures in the negative photoresist layer of the second microstructure master blank;

wherein creating a second generation stamper and impinging the laser beam through the second outer layer of the second microstructure master blank at least partially overlap in time.

32. A method according to claim 31 wherein the microstructures comprise optical and/or mechanical microstructures.

33. A method of fabricating a microstructure master comprising:

placing on a cylindrical platform, a microstructure master blank that comprises a first outer layer, a negative photoresist layer on the first outer layer and a second outer layer on the negative photoresist layer, such that the first outer layer is adjacent the cylindrical platform and the second outer layer is remote from the cylindrical platform;

impinging a laser beam through the second outer layer into the negative photoresist layer while simultaneously rotating the cylindrical platform about an axis thereof and while simultaneously axially rastering the laser beam across at least a portion of the negative photoresist layer to image the microstructures in the negative photoresist layer;

separating the first outer layer from the cylindrical platform;

separating the first outer layer from the negative photoresist layer;

developing the microstructures that were imaged in the negative photoresist layer;

creating a second-generation stamper from the microstructures that were developed in the negative photoresist layer by contacting the microstructures to a stamper blank; and

forming a plurality of third generation microstructure end products directly from a stamper.

34. A method according to claim 33 wherein the microstructures comprise optical and/or mechanical microstructures.