Maskless photolithography for etching and deposition

• US 6,998,219 B2
• Filed: 06/25/2002
• Issued: 02/14/2006
• Est. Priority Date: 06/27/2001
• Status: Active Grant

• 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): Kim, Peter B.
• Application Number:
  US10/179,565
• Publication Number:
  US 20030190536A1
• Time in Patent Office: 1,330 Days
• Field of Search: 430/311, 430/30, 355/53, 355/73, 355/71, 428/457, 396/506, 347/239, 349/43, 427/581
• US Class Current: 430/311
• CPC Class Codes: G03F 7/0041 providing an etching agent upon exposure G03F7/075 takes precedence; photolytic halogen compounds G03F7/0295
• 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 7/2043 with the production of a chemical active agent from a fluid, e.g. an etching agent; with meterial deposition from the fluid phase, e.g. contamination resists
• CPC Class Codes: G03F 7/2051 Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source G03F7/70 takes precedence
• 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 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

The present invention relates to maskless photolithography using a patterned light generator for creating 2-D and 3-D patterns on objects using etching and deposition techniques. In an embodiment, the patterned light generator uses a micromirror array to direct pattern light on a target object. In an alternate embodiment, the patterned light generator uses a plasma display device to generate and direct patterned light onto a target object. Specifically, the invention provides a maskless photolithography system and method for photo stimulated etching of objects in a liquid solution, patterning glass, and photoselective metal deposition. For photo stimulated etching of objects in a liquid solution, the invention provides a system and method for immersing a substrate in an etchant solution, exposing the immersed substrate to patterned light, and etching the substrate according to the pattern of incident light. For patterning photoreactive glass, the invention provides a system and method for exposing photosensitive or photochromic glass, and washing the target glass with rinse and acid etchant solutions. For photoselective metal deposition, the invention provides a system and method for coating and rinsing a substrate prior to exposure exposing the substrate to a patterned light generator to activate areas corresponding to the incident light pattern, and plating the substrate in the area activated by the light after exposure. By providing a maskless pattern generator, the invention advantageously eliminates the problems associated with using masks for photo stimulated etching, patterning glass, and photoselective metal deposition.

Claims

1. A maskless photolithography system for photoselective metal deposition on a substrate comprising:

a. a computer system for generating mask patterns and alignment instructions;

b. a maskless patterned light generator, radiating a patterned light beam, operably connected to and controllable by said computer system;

c. a light activated catalytic coating bath to coat said substrate; and

d. a deposition bath for depositing metal on said substrate corresponding to regions activated by said patterned light beam;

wherein said substrate, coated with said light activated catalyst, receives radiation from said patterned light beam, wherein said patterned light beam impinging on the substrate creates activated regions on the substrate corresponding to said patterned light beam, wherein metal in solution is deposited on said activated regions of the substrate.

2. The system of claim 1, wherein said light activated catalytic coating bath comprises a solution of tin oxide.

3. The system of claim 1, further comprising a rinse bath to rinse the substrate after the substrate is coated with said light activated catalytic coating and before the substrate is exposed to said patterned light beam.

4. The system of claim 1, further comprising a surface coating bath to apply a coating to the substrate after the substrate receives said patterned light and before said metal is deposited on the substrate.

5. The system of claim 4, wherein said surface coating bath comprises palladium chloride.

6. The system of claim 1, wherein said deposition bath comprises an electro-less metal plating solution.

7. The system of claim 1, wherein said deposition bath comprises an electrolytic metal plating solution, an anode, electrically attached to said substrate, and a cathode, immersed in said metal plating solution and positioned so as not to make electrical contact with said substrate, wherein said anode is connected to the positive terminal of a voltage source, and said cathode is connected to a negative terminal of said voltage source, wherein said substrate is electrically biased to receive said metal plating.

8. The system of claim 1, wherein said maskless patterned light generator comprises:

a. an array of positionable micromirrors, wherein said micromirrors reflect light according to said mask patterns provided by said computer system;

b. an optical system for generating, collimating, and directing the light beam to said micromirror array; and

c. an optical system for further collimating the light beam reflected from said micromirrors and directing said patterned light beam onto said substrate and to create patterns on the substrate corresponding to said mask patterns.

9. The system of claim 8, further comprising a computer controlled pattern modulation system, for varying the angular position of said micromirrors and duration of the exposure of the substrate, wherein said modulation system alters the positioning of said micromirrors in response to instructions provided by said computer, whereby pixelation and stiction are reduced.

10. The system of claim 1, wherein said maskless patterned light generator comprises a plasma display, having individually addressable pixels, operably connected to and controllable by said computer system, wherein said display generates said patterned light beam corresponding to said mask patterns provided by said computer system to expose the substrate to said patterned light beam and to create patterns on the substrate corresponding to said mask patterns.

11. The system of claim 1, further comprising a manually controlled alignment fixture for detachably mounting the substrate, 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 substrate beneath the light beam, wherein said alignment fixture is moved in three dimensions in response to mechanical alignments directly provided by a user.

12. The system of claim 1, further comprising a computer controlled pattern alignment system, for providing electrical alignment of said mask 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 in response to instructions provided by said computer according to said alignment information, so that said mask pattern is shifted in at least one coplanar direction.

13. The system of claim 11, further comprising an optical viewer to allow optical monitoring of positioning of the substrate mounted in said alignment fixture by visually verifying that an image projected on the substrate is properly aligned.

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

15. A maskless photolithography system for photoselective metal deposition on a substrate comprising:

a means for generating mask patterns and alignment instructions;

a means for radiating a patterned light beam in accordance with the generated mask patterns, wherein the means for radiating a patterned light beam shifts the patterned light beam in accordance with the alignment instructions;

a means for coating a substrate with a light activated catalyst;

a means for exposing the coated substrate to the patterned light beam, wherein the light activated catalyst is made receptive for deposition of metal where light impinges on the coated substrate; and

a means for subjecting the coated substrate to a chemical bath, wherein a metal in the chemical bath is deposited on the exposed regions of the coated substrate.

16. The system according to claim 15, further comprising a means for coating a substrate with additional coatings after exposing the coated substrate to a patterned light beam.