Maskless photolithography using plasma displays

• US 6,764,796 B2
• Filed: 06/25/2002
• Issued: 07/20/2004
• Est. Priority Date: 06/27/2001
• Status: Expired due to Fees

• Current Assignee: University of South Florida (State University System of Florida)
• Original Assignee: University of South Florida (State University System of Florida)
• Inventors: Fries, David P.
• Primary Examiner(s): Young, Christopher G.
• Application Number:
  US10/179,540
• Publication Number:
  US 20030190535A1
• Time in Patent Office: 756 Days
• Field of Search: 430/5, 430/22, 430/313, 430/396, 250/492.1, 250/492.22, 250/492.2, 355/67, 355/77, 378/34, 716/19, 716/21
• US Class Current: 430/22
• 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 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G03F 9/00 Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically G03F7/22 takes precedence; preparation of photographic masks G03F1/00; within photographic printing apparatus for making copies G03B27/00

Abstract

The present invention is a maskless photolithography system and method using a plasma display for creating two-dimensional and three-dimensional structures. Advantageously, the invention does not require masks, templates or stencils to create each of the planes or layers on a multi layer two-dimensional or three-dimensional structure. The invention employs a plasma display having individually addressable pixels to generate and direct light onto an object that has photoreactive or photoresist compounds applied to the exposed surface. Unlike conventional plasma displays that generate visible light, the plasma display of the current invention lacks the phosphor coating conventionally used to convert ultraviolet (UV) light to visible light. Therefore, the instant plasma display generates UV light appropriate for reactive processes typically used in photolithography. The desired pattern is designed and stored using conventional computer aided drawing techniques and is used to control the pixels of the plasma display to generate the corresponding desired pattern. Patterned light is directed onto the object to create light and dark spots according to the pattern. In an alternative embodiment, a fixture three dimensions, for mounting of the substrate and allows the substrate to be moved three dimensions, providing alignment in two, coplanar dimensions and the capability to produce three dimensional structures by aligning the substrate in a third dimension perpendicular to the two coplanar dimensions. The system and method is easily reconfigurable and allows rapid prototyping of microscopic and macroscopic devices.

Claims

1. A system for maskless photolithography comprising:

a. a computer system for generating mask patterns; and

b. a plasma display, having individually addressable pixels, operably connected to and controllable by said computer system, wherein said display generates a patterned light beam corresponding to said mask patterns provided by said computer system to expose an object to said patterned light beam and to create patterns on the object corresponding to said mask patterns.

2. The system of claim 1, wherein said plasma display radiates ultraviolet light (UV) and does not have phosphor coatings for converting ultraviolet light (UV) to visible light.

3. The system of claim 1, further comprising an optical system for collimating said patterned light beam emitted from said plasma display and directing said patterned light beam onto an object.

4. The system of claim 1, further comprising a manually controlled alignment fixture for mounting the object, wherein said alignment fixture is movable in coplanar first and second dimensions, and in a third dimension direction substantially perpendicular to said first and second coplanar dimensions and substantially parallel to said patterned light beam;

said fixture providing three dimensional alignment of the object beneath said patterned light beam, wherein said alignment fixture is moved in three dimensions in response to mechanical alignments directly provided by a user.

5. The system of claim 1, further comprising a computer controlled pattern alignment system, for receiving alignment information and for providing electrical alignment of said patterns in coplanar first and second dimensions, wherein said pattern alignment system adjusts the alignment of said mask patterns in coplanar first and second dimensions by shifting addressed plasma pixels in response to instructions provided by said computer according to said alignment information, so that said pattern is translated in at least one coplanar direction on said plasma display.

6. The system of claim 1, further comprising an optical viewer to allow optical monitoring of positioning of the object mounted in said alignment fixture by visually verifying that a pattern projected on the object is properly aligned.

7. The system of claim 1, further comprising an optical filter, removably mounted in said patterned light beam to selectively filter light impinging on the object to prevent exposure of the object during an alignment procedure.

8. The system of claim 7 wherein said optical filter is an ultraviolet (UV) filter.

9. The system of claim 1 wherein the object is a photoresist coated substrate.

10. The system of claim 1 wherein the object is a photoreactive coated substrate.

11. A method for maskless photolithography comprising:

a. receiving mask pattern information corresponding to a desired pattern to be created on an object;

b. generating mask patterns based on received mask pattern information;

c. providing said mask patterns to a plasma display having individually addressable pixels, operably connected to and controllable by a computer system;

d. generating a patterned light beam corresponding to said mask pattern;

e. allowing exposure of an object to said patterned light beam; and

f. repeating steps (a-e) to allow creation of a desired pattern on the object.

12. The method of claim 11, wherein said plasma display radiates ultraviolet light (UV) and does not have phosphor coatings for converting ultraviolet light (UV) to visible light.

13. The method of claim 11, further comprising collimating said patterned light beam generated by said plasma display and directing said patterned light beam onto the object.

14. The method of claim 11, further comprising providing selective filtering of said patterned light beam impinging on the object to prevent reactive exposure of the object during an alignment procedure.

15. The method of claim 14 wherein said optical filter is an UV filter.

16. The method of claim 14, wherein said providing selective filtering of said patterned light beam further comprises placing an optical filter in and removing an optical filter from said patterned light beam path.

17. The method of claim 11, further comprising:

a. allowing manual alignment of the object under said patterned light beam by moving the object in three dimensions, wherein the object is moved in coplanar first and second dimensions, and moved in a third dimension direction substantially perpendicular to said first and second coplanar dimensions, and substantially parallel to said patterned light beam radiated from said plasma display; and

b. allowing optical monitoring of alignment of the object under said patterned light beam to visually verify that an image projected on the object is properly aligned.

18. The method of claim 17, wherein said allowing manual alignment of the object further comprises manually aligning a object under said patterned light beam by moving the object in three dimensions in response to mechanical alignments provided by a user.

19. The method of claim 17, wherein said allowing optical monitoring further comprises optically monitoring positioning of the object under said patterned light beam to visually verify that an image projected on the object is properly aligned.

20. The method of claim 11, further comprising electronically aligning the mask patterns by:

a. receiving alignment information corresponding to alignment of the desired mask pattern projected onto a object;

b. generating alignment instructions based on received alignment information;

c. providing alignment instructions, based on said alignment information, to said plasma display to further align said mask patterns in the coplanar first and second dimensions; and

d. adjusting addressing of said pixels of said plasma display according to said alignment instructions by shifting the mask pattern in at least one of the coplanar first and second dimensions.

21. The method of claim 11, wherein said receiving mask pattern information further comprises providing mask pattern information corresponding to a desired pattern to be created on a object.

22. The method of claim 11 wherein the object is a photoresist coated object and successive layers are etched away from the substrate according to the projected mask pattern.

23. The method of claim 11 wherein the substrate is a photoreactive coated substrate and successive layers are added to the substrate according to the projected mask pattern.

24. A method for maskless photolithography comprising:

a. providing a computer system for generating mask patterns; and

b. providing a plasma display, having individually addressable pixels, operably connected to and controllable by said computer system, wherein said display generates a patterned light beam according to said mask patterns provided by said computer system, wherein said display generates a patterned light beam corresponding to said mask patterns provided by said computer system to expose an object to said patterned light beam and to create patterns on the object corresponding to said mask patterns.

25. The method of claim 24, wherein said plasma display radiates ultraviolet light (UV) and does not have phosphor coatings for converting ultraviolet light (UV) to visible light.

26. The method of claim 24, further comprising providing a computer system for generating alignment instructions, wherein said system provides instructions to align patterns in coplanar first and second dimensions, by shifting addressed plasma pixels in response to instructions provided by said computer according to said alignment information so that the pattern is translated in at least one coplanar direction.

27. The method of claim 24, further comprising providing an optical system for collimating and directing said patterned light beam onto the object.

28. The method of claim 24, further comprising providing a manually controlled alignment fixture for mounting the object, wherein said alignment fixture is movable in coplanar first and second dimensions, and in a third dimension direction substantially perpendicular to said first and second coplanar dimensions and substantially parallel to said patterned light beam radiated from said plasma display;

said fixture providing three dimensional alignment of the object beneath said patterned light beam, wherein said alignment fixture is moved in three dimensions in response to mechanical alignments directly provided by a user.

29. The method of claim 24, further comprising providing an optical viewer to allow optical monitoring of positioning of the object mounted in said alignment fixture by visually verifying that an image projected on the object is properly aligned.

30. A computer system for maskless photolithography comprising:

a. a computing device comprising a display, a central processing unit (CPU), operating system software, memory for storing data, a user interface, and input/output capability for reading and writing data;

said computing device operably connected to and operating in conjunction with a maskless photolithography system;

b. computer program code for;

1) receiving mask pattern information corresponding to a desired pattern to be created on an object;

2) generating mask patterns based on received mask pattern information;

3) providing said mask patterns to a plasma display having individually addressable pixels, operably connected to and controllable by a computer system;

4) generating a patterned light beam corresponding to said mask pattern;

5) allowing exposure of an object to said patterned light beam; and

6) repeating steps (1-5) to allow creation of a desired pattern on the object;

wherein said computing device operates in conjunction with said maskless photolithography system and executes said computer code to control said plasma display according to said received pattern information.

31. The computer system of claim 30 further comprising a dedicated interface for receiving alignment information.

32. The computer system of claim 30 further comprising a dedicated interface for providing pattern information and alignment commands to a plasma display.

33. A computer program product recorded on computer readable medium for a maskless photolithography system comprising:

a. computer readable medium for receiving mask pattern information corresponding to a desired pattern to be created on an object;

b. computer readable medium for generating mask patterns based on received mask pattern information;

c. computer readable medium for providing said mask patterns to a plasma display having individually addressable pixels, operably connected to and controllable by a computer system;

d. computer readable medium for generating a patterned light beam corresponding to said mask pattern;

e. computer readable medium for allowing exposure of an object to said patterned light beam; and

f. computer readable medium for repeating steps (a-e) to allow creation of a desired pattern on the object;

wherein said computer program product provides instructions for a computer system operating in conjunction with said maskless photolithography system to control said plasma display according to said received pattern information.