METHODS FOR MASTERING MICROSTRUCTURES THROUGH A SUBSTRATE USING NEGATIVE PHOTORESIST

• US 20110070547A1
• Filed: 12/01/2010
• Published: 03/24/2011
• Est. Priority Date: 09/11/2003
• Status: Active Grant

• Current Assignee: Bright View Technologies Corporation (Tredegar Corporation)
• Original Assignee: Bright View Technologies Corporation (Tredegar Corporation)
• Inventors: Wood, Robert L., Freese, Robert P., Rinehart, Thomas A.
• Granted Patent: US 8,263,318 B2
• Time in Patent Office: Days
• US Class Current: 430/325
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G02B 3/0025 Machining, e.g. grinding, polishing, diamond turning, manufacturing of mould parts
• 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 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• 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 7/0007 Filters, e.g. additive colour filters; Components for display devices
• CPC Class Codes: G03F 7/0015 Production of aperture devices, microporous systems or stamps
• CPC Class Codes: G03F 7/2053 using a laser ablative removal B41C
• CPC Class Codes: G03F 7/24 Curved surfaces G03F7/70 takes precedence

Abstract

Microstructures are fabricated by impinging a radiation beam, such as a laser beam, through a substrate that is transparent to the laser beam, into a negative photoresist layer on the substrate. The negative photoresist layer may be subsequently developed to provide a master for optical and/or mechanical microstructures. Related systems, microstructure products and microstructure masters also are disclosed.

Claims

1. A method of fabricating an array of microstructures comprising:

scanning a radiation beam at varying amplitude through a substrate that is transparent thereto into a negative photoresist layer on the substrate to image the array of microstructures in the negative photoresist layer.

3. A method according to claim 1 wherein the negative photoresist layer is thicker than the array of microstructures and wherein scanning comprises scanning a radiation beam at varying amplitude through a substrate that is transparent thereto into a negative photoresist layer on the substrate to image a buried array of microstructures in the negative photoresist layer, adjacent the substrate.

4. A method according to claim 1 wherein at least some of the microstructures include a base and a top that is narrower than the base and wherein scanning comprises scanning a radiation beam at varying amplitude through a substrate that is transparent thereto into a negative photoresist layer on the substrate to image the array of microstructures in the negative photoresist layer with the bases adjacent the substrate and the tops remote from the substrate.

5. A method according to claim 1 wherein the negative photoresist layer is of variable thickness thereacross, wherein a minimum thickness of the negative photoresist layer is thicker than the microstructures and wherein scanning comprises scanning a radiation beam at varying amplitude through a substrate that is transparent thereto into a negative photoresist layer on the substrate to image buried microstructures beneath the negative photoresist layer, adjacent the substrate, that are independent of the variable thickness of the negative photoresist layer.

6. A method according to claim 1 wherein the negative photoresist layer includes impurities thereon, remote from the substrate, wherein the negative photoresist layer is thicker than the microstructures and wherein scanning comprises scanning a radiation beam at varying amplitude through a substrate that is transparent thereto into a negative photoresist layer on the substrate to image buried microstructures in the negative photoresist layer, adjacent the substrate, that are not distorted by the impurities.

7. A method according to claim 1 wherein the substrate is a flexible substrate.

8. A method according to claim 1 wherein the negative photoresist layer is on a cylindrical platform such that the substrate is on the negative photoresist layer remote from the cylindrical platform, and wherein scanning comprises:

rotating the cylindrical platform about an axis thereof while simultaneously axially rastering the radiation beam at varying amplitude through the substrate that is on the cylindrical platform across at least a portion of the negative photoresist layer to image the array of microstructures in the negative photoresist layer.

9. A method according to claim 8 further comprising simultaneously translating the cylindrical platform and/or radiation beam axially relative to one another.

10. A method according to claim 9 further comprising simultaneously continuously varying the amplitude of the radiation beam.

11. A method according to claim 1 wherein the substrate is at least about one square foot in area.

12. A method according to claim 1 wherein scanning is performed continuously on the substrate for at least about 1 hour.

13. A method according to claim 1 wherein scanning is performed continuously on the substrate for at least about 1 hour to fabricate at least about one million microstructures.

15. A method according to claim 1 further comprising:

developing the microstructures that are imaged in the negative photoresist layer to provide a microstructure array master.

16. A method according to claim 1 wherein the substrate is cylindrical, ellipsoidal or polygonal in shape.

17. A method according to claim 1 further comprising translating the substrate and/or radiation beam relative to one another while scanning the radiation beam.

18. A method according to claim 15 further comprising:

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

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

19. A method according to claim 1 wherein the microstructures comprise optical microstructures.