Micromechanical devices with spring tips

• US 5,867,202 A
• Filed: 12/13/1996
• Issued: 02/02/1999
• Est. Priority Date: 12/15/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mignardi, Michael A., Knipe, Richard L., Strumpell, Mark H.
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): NGUYEN, THINH H
• Application Number:
  US08/768,007
• Time in Patent Office: 781 Days
• Field of Search: 347/239, 348/571, 359/224, 359/214, 359/221, 359/223, 359/226, 359/198, 359/295
• US Class Current: 347/239
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micromechanical device (50) with spring tips (60) and its method of manufacture. A micromechanical device (50) is formed such that there is a deflectable element (36) suspended by at least one hinge (24a) over an air gap, at the bottom of which are landing stops (34a). The element (36) deflects on said hinge and comes into contact with the landing stops (34a) via at least one small metal protrusion (60), or spring tip. The spring tip flexes upon contact allowing more even distribution of forces and less wear and adhesion. The spring tips are formed in standard semiconductor processing steps with the addition of patterning the metal layer (64) from which the hinges are formed to create separated metal elements. When the deflectable element is formed, the metal forming that element bonds to the separated metal elements at the tips, thereby forming the spring tips.

Claims

1. A micromechanical device comprising:

a substrate;

addressing circuitry formed upon said substrate operable to activate said micromechanical device;

at least one hinge;

a deflectable element having a landing tip suspended above said addressing circuitry by at least one hinge;

at least one landing stop formed on said substrate proximate said addressing circuitry; and

a flexible tip extending from said landing tip such that when said deflectable element is activated and deflects towards said addressing circuitry, said flexible tip comes in contact with said landing stop.

2. The micromechanical device of claim 1 wherein said micromechanical device is a digital micromirror device.

3. The micromechanical device of claim 1 wherein said micromechanical device is an actuated mirror array.

4. The micromechanical device of claim 1 wherein said deflectable element a cantilever hinge spatial light modulator element.

5. The micromechanical device of claim 1 wherein said deflectable element a torsion hinge spatial light modulator element.

6. The micromechanical device of claim 1 wherein said deflectable element of is a double-level spatial light modulator element.

7. A method of manufacturing a micromechanical device with spring hinges, comprising the steps of:

forming addressing circuitry upon a substrate;

forming landing stops upon said substrate proximate to said addressing circuitry;

spinning a first spacer layer material over said landing stops and said addressing circuitry;

forming vias in said spacer material;

depositing a first metal layer such that said first metal layer fills said vias;

patterning and etching said first metal layer to form support posts, at least one hinge, and at least one metal element separate from said posts and said hinge;

depositing a second metal layer;

patterning and etching said second metal layer to form deflectable elements with landing tips, such that said metal elements are attached to said landing tips at the points at which said landing tips will contact said landing stops; and

removing said spacer material to allow said deflectable element to move freely when activated by said addressing circuitry.

8. The method of claim 7, further comprising the steps of:

spinning a second spacer layer after the step of patterning and etching said second metal layer but before the step of removing said spacer;

forming vias in said second spacer layer;

depositing a third metal layer such that said third metal layer fills the vias; and

patterning and etching said third metal layer to form reflective elements.

9. The method of claim 7, wherein said patterning said first metal layer to form at least one hinge step forms one hinge.

10. The method of claim 7, wherein said patterning said first metal layer to form at least one hinge step forms two hinges.