Support post architecture for micromechanical devices

• US 5,631,782 A
• Filed: 06/07/1995
• Issued: 05/20/1997
• Est. Priority Date: 11/02/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Smith, Gregory C., Boysel, Robert M.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US08/474,867
• Time in Patent Office: 713 Days
• Field of Search: 359/871, 359/872, 359/883, 359/884, 359/214, 359/224, 359/295, 359/291, 359/292, 359/293, 348/771
• US Class Current: 359/871
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G06K 15/1252 using an array of light modulators, e.g. a linear array
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

Support pillar 426 for use with a micromechanical device, particularly a digital micromirror device, comprising a pillar material 422 supported by a substrate 400 and covered with a metal layer 406. The support pillar 426 is fabricated by depositing a layer of pillar material on a substrate 400, patterning the pillar layer to define a support pillar 426, and depositing a metal layer 406 over the support pillar 426 enclosing the support pillar. A planar surface even with the top of the pillar may be created by applying a spacer layer 432 over the pillars 426. After applying the spacer layer 432, the spacer layer 432 is etched to expose the tops of the pillars.

Claims

1. A micromirror device comprising:

a substrate;

at least one hinge support pillar supported by said substrate, said hinge support pillar comprised of a first pillar material enclosed by a first metal sheath and said substrate;

at least one hinge connected to said hinge support pillar;

at least one mirror support pillar connected to said hinge, said mirror support pillar comprised of a second pillar material enclosed by a second metal sheath and a layer forming said hinge; and

at least one mirror element supported by said mirror support pillar.

2. The micromirror device of claim 1 wherein said first pillar material and said second pillar material are selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride.

3. The micromirror device of claim 1 wherein said first metal sheath is an aluminum alloy.

4. The micromirror device of claim 1 wherein said second metal sheath is an aluminum alloy.

5. The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy.

6. The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing titanium.

7. The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing silicon.

8. The micromirror device of claim 1 wherein said at least one hinge is an aluminum alloy containing 1% silicon and 0.2% titanium.

9. The micromirror device of claim 1 wherein said first pillar material is 1.0 μ

m thick.

10. The micromirror device of claim 1 wherein said second pillar material is 2.2 μ

m thick.

11. A micromirror device comprising:

a substrate;

at least one hinge support pillar supported by said substrate, said hinge support pillar comprising a pillar material enclosed by a metal sheath and said substrate;

at least one hinge connected to said hinge support pillar; and

at least one mirror element supported by said at least one hinge.

12. The micromirror device of claim 11 wherein said metal sheath is an aluminum alloy.

13. The micromirror device of claim 11 wherein said pillar material is selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride.

14. The micromirror device of claim 11 wherein said at least one hinge is an aluminum alloy.

15. The micromirror device of claim 11 wherein said at least one hinge is an aluminum alloy containing titanium.

16. The micromirror device of claim 11 wherein said at least one hinge is an aluminum alloy containing silicon.

17. The micromirror device of claim 11 wherein said at least one hinge is an aluminum alloy containing 1% silicon and 0.2% titanium.

18. A support pillar for a micromechanical device comprising:

a substrate;

a pillar material supported by said substrate, said pillar material formed in the shape of the desired support pillar; and

a metal layer at least partially supported by said substrate, wherein said metal layer is formed over said pillar material enclosing said pillar material.

19. The support pillar of claim 18 wherein said pillar material is selected from the group consisting of a photoresist, polysilicon, an oxide, a nitride, and an oxynitride.

20. The support pillar of claim 18 wherein said metal layer is an aluminum alloy.