Dynamic mask projection stereo micro lithography

• US 7,088,432 B2
• Filed: 09/27/2001
• Issued: 08/08/2006
• Est. Priority Date: 09/27/2000
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Zhang, Xiang
• Primary Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US10/380,229
• Publication Number:
  US 20050259785A1
• Time in Patent Office: 1,776 Days
• Field of Search: 427/510, 427/512, 427/553, 427/555, 264/401, 355/32, 355/53, 355/77
• US Class Current: 355/77
• CPC Class Codes: B29C 64/124 using layers of liquid which are selectively solidified
• CPC Class Codes: B29C 64/129 characterised by the energy source therefor, e.g. by global irradiation combined with a mask
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• 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 7/70416 2.5D lithography

Abstract

Three-dimensional structures are fabricated by a process in which a 3D solid model is designed by software at a PC and sliced into a series of 2D layers. Each 2D layer is displayed at a dynamic mask via micro-mirror deflections projected onto a photoresist to form a layer, which is lowered and the process is repeated to build the object layer by layer.

Claims

1. A method for forming a three-dimensional structure from a computer-stored image, comprising the steps of:

(a) providing a photo-curable composition;

(b) providing a source of actinic light for curing said composition;

(c) arranging a digital micro-mirror display to reflect said actinic light to said composition;

(d) providing a computer stored image;

(e) computer-generating a plurality of sequential two-dimensional slices from said image;

(f) using said plurality of sequential two-dimensional slices to sequentially control said digital micro-mirror display to reflect said actinic light to said composition as sequential images of said selected slice;

(g) passing said reflected light images through a reduction projection system to enhance resolution; and

(h) sequentially focusing said reflected light images to a plurality of successive locations in said composition to at least partially cure successive two-dimensional layers therein corresponding to said sequential two-dimensional slices until the three-dimensional structure is formed;

wherein a portion of said reflected light is used to view the composition as said three-dimensional structure is being formed.

2. The method of claim 1 in which said computer-stored image is a solid 3D model.

3. The method of claim 2 in which said model is a CAD image.

4. The method of claim 1 in which said sequential locations are vertical locations.

5. The method of claim 4 in which actinic light reflected from said digital micro-mirror display is focused by optics to a predetermined vertical location, and wherein sequential locations in said composition are obtained by relative vertical movement of said composition and said optics.

6. The method of claim 5 in which sequential locations in said composition are obtained by sequential downward vertical movement of said composition.

7. The method of claim 1 in which a light absorbing chemical dopant is dispersed in the photo-curable composition, for precisely controlling the curing depth.

8. An apparatus for forming a three-dimensional structure in a photo-curable composition from a computer-stored image, comprising:

a source of actinic light for curing said composition;

a digital micro-mirror display arranged to reflect said actinic light to said composition;

a computer for providing a computer stored image and generating a plurality of sequential two-dimensional slices from said image;

means for using said sequential two-dimensional slices to control said digital micro-mirror display to sequentially reflect said actinic light to said composition as a sequence of images of said slices;

means for focusing and enhancing resolution of said reflected light images sequentially to a plurality of locations in said composition to at least partially cure successive two-dimensional layers therein corresponding to said sequential two-dimensional slices whereby to enable the three-dimensional structure to be formed; and

means for viewing a portion of said reflected light whereby to enable viewing of the composition as said three-dimensional structure is being formed.

9. The apparatus of claim 8 in which said computer-stored image is a solid 3D model.

10. The apparatus of claim 9 in which said model is a CAD image.

11. The apparatus of claim 8 in which said sequential locations are vertical locations.

12. The apparatus of claim 11 in which the means for focusing and enhancing resolution of said reflected light images comprises optics focusing said actinic light reflected from said digital micro-mirror display to a predetermined vertical location, and means for relative vertical movement of said composition and said optics.

13. The apparatus of claim 12 in which said means for relative vertical movement of said composition and said optics comprises means for sequential downward vertical movement of said composition.

14. The apparatus of claim 13 in which said means for sequential downward vertical movement of said composition comprises a computer controlled z elevator stage carrying the composition.