Support post architecture for micromechanical devices

• US 6,447,126 B1
• Filed: 06/07/1995
• Issued: 09/10/2002
• Est. Priority Date: 11/02/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Hornbeck, Larry J.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US08/482,098
• Time in Patent Office: 2,652 Days
• Field of Search: 359/871, 359/872, 359/883, 359/884, 359/224, 359/295, 359/291
• US Class Current: 359/871
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0361 Tips, pillars
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• 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

A 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, holes 434 are patterned into the spacer layer to remove any spacer material that is covering the pillars. The spacer layer is then reflowed to fill the holes and lower the surface of the spacer layer such that the surface is coplanar with the tops of the support pillars 426.

Claims

1. A micromirror device comprising:

a substrate;

at least one hinge support pillar supported by said substrate, said hinge support pillar comprising a first metal sheath fabricated by conformably coating a first pillar-shaped material with metal and removing said first pillar-shaped material;

at least one hinge connected to said hinge support pillar;

at least one mirror support pillar connected to said hinge, said mirror support pillar comprising a second metal sheath fabricated by conformably coating a second pillar-shaped material with metal and removing said second pillar-shaped material; and

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

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

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

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

11. The micromirror device of claim 1 wherein said at least one mirror element is an aluminum alloy.

12. The micromirror device of claim 1 further comprising:

a thin metal layer between said substrate and said at least one hinge support pillar.

13. The micromirror device of claim 1 wherein each of said at least one mirror support pillars is supported by two of said hinges.

2. A micromirror device comprising:

a substrate;

at least one hinge support pillar supported by said substrate, said hinge support pillar comprising a metal sheath fabricated by conformably coating a pillar-shaped material with metal and removing said pillar-shaped material;

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

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

3. The micromirror device of claim 2 wherein said metal sheath is an aluminum alloy.

14. The micromirror device of claim 2 wherein said at least one hinge is an aluminum alloy.

15. The micromirror device of claim 2 wherein said at least one mirror element is an aluminum alloy.

16. The micromirror device of claim 2 further comprising:

a thin metal layer between said substrate and said at least one hinge support pillar.

17. The micromirror device of claim 2 wherein each of said at least one mirror elements is supported by two of said hinges.

4. A support pillar for a micromechanical device comprising:

a substrate;

a metal sheath supported by said substrate, said metal sheath fabricated by conformably coating a pillar-shaped material and removing said pillar-shaped material.

5. The support pillar of claim 4 wherein said metal sheath is an aluminum alloy.

6. The support pillar of claim 4 further comprising:

a thin metal layer between said substrate and said metal sheath.

7. The support pillar of claim 6 wherein said thin metal layer is an aluminum alloy.