Method of manufacturing a micro-electromechanical system (MEMS) device

• US 8,429,809 B2
• Filed: 01/10/2012
• Issued: 04/30/2013
• Est. Priority Date: 05/13/2008
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Orcutt, John W.
• Primary Examiner(s): Kim, Paul D
• Application Number:
  US13/347,264
• Publication Number:
  US 20120102730A1
• Time in Patent Office: 476 Days
• Field of Search: 295/921, 296/11, 296/22, 298/25, 298/30, 298/43, 298/46, 298/74, 216/33, 216/38, 216/80, 257/E21.218, 257/415, 257/419, 257/619, 257/684, 361/277, 361/278, 361/280, 361/281, 438/52, 438/53, 438/71, 438/121
• US Class Current: 29/595
• CPC Class Codes: B29D 11/00596 Mirrors
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49131 by utilizing optical sighting device
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49204 Contact or terminal manufacturing

Abstract

A method for manufacturing a mirror device is presented. The method includes forming a mirror from a first substrate and forming a hinge/support structure from a second substrate. The hinge/support structure is formed with a recessed region and a torsional hinge region. The mirror is attached to the hinge/support structure at the recessed region. Further, a driver system is employed to cause the mirror to pivot about the torsional hinge region.

Claims

1. A method of manufacturing a micro-electromechanical systems (MEMS) device, the method comprising:

forming a mirror from a first substrate;

forming a hinge/support structure from a second substrate, including forming a recessed region using a recess etch and forming torsional hinge regions using a through-substrate etch; and

attaching the mirror within the recessed region to the hinge/support structure.

2. The method of claim 1, wherein forming the mirror from the first substrate employs a sawing process.

3. The method of claim 1, further comprising adjusting a thickness of the recessed region to substantially balance the mirror and the hinge/support region about a single axis of rotation.

4. The method of claim 1, further comprising forming a mirror subassembly by coupling a plurality of magnets to a plurality of hinge landings using adhesive bonding.

5. The method of claim 4, further comprising changing a volume of a magnet to substantially balance the mirror subassembly about a single axis of rotation.

6. The method of claim 4 further comprising locating electromagnet coils within a MEMS device casing;

and mounting the mirror subassembly into the MEMS device casing.

20. The method of claim 1, wherein the first and second substrates each comprises single crystalline silicon.

21. The method of claim 20, wherein using the recess etch comprises removing a portion of a backside of the second substrate, and using the through-substrate etch comprises etching using patterning accomplished on a front side of the second substrate.

22. The method of claim 21, wherein forming the mirror includes polishing an upper surface of the first substrate to provide a mirror surface.

23. The method of claim 22, wherein the mirror is formed with a flatness and shape having a length of about 16 times a thickness and having a width of about 8 times the thickness.

24. The method of claim 22, wherein the mirror is formed with a length of about 16 millimeters or less, and a width of between about 1-8 millimeters.

25. The method of claim 22, wherein the mirror is formed with a rectangular shape having a long axis dimension of about 8 millimeters, a short axis dimension of about 4 millimeters, and a thickness of about 0.5 millimeters.

7. A method of manufacturing a micro-electromechanical systems (MEMS) device, the method comprising:

providing a first substrate;

forming a mirror from the first substrate;

providing a second substrate;

patterning a front side of the second substrate;

performing a through-substrate etch on the second substrate, thereby forming a hinge/support structure that includes torsional hinge regions; and

coupling the mirror to the hinge/support structure, wherein the torsional hinge regions remain exposed;

wherein removing the portion of the second substrate comprises etching a backside of the second substrate to remove a portion of the backside of the second substrate prior to performing the through-substrate etch on the second substrate.

8. A method of making a MEMS device, comprising:

forming a flat rectangular mirror of a first width and a first length from a first substrate of a first thickness;

forming a hinge/support structure from a second substrate of a second thickness, including;

patterning and etching the second substrate to form a recessed region of a second width greater than the first width, and a second length less than the first length;

the second substrate having a third thickness, reduced from the second thickness, at the recessed region; and

patterning and etching the second substrate in a through-substrate etch to form a torsional hinge; and

mounting the mirror to the hinge/support structure, with the mirror positioned within the recessed region for rotation of the mirror length about a hinge axis defined by the torsional hinge.

9. The method of claim 8, wherein the through-substrate etch defines hinges coupling hinge anchors and mirror landings beyond respective width ends of the recessed region.

10. The method of claim 9, further comprising coupling magnets at respective mirror landings.

11. The method of claim 10, wherein the magnets are mounted to both of the opposite sides of the second substrate, with magnetic vectors of magnets mounted at the same mirror landing facing in same directions and with magnetic vectors of magnets mounted at different mirror landings facing in opposite directions.

12. The method of claim 11, wherein the first thickness is less than the second thickness.

13. The method of claim 12, wherein the third thickness is equal to one-half a difference between the second thickness and the first thickness.

14. The method of claim 13, further comprising:

mounting the combined mirror and hinge/support structure within a bracket of an assembly including a coil and core tips positioned to drive the magnets to oscillate the mirror and including mirror stops positioned to limit pivoting travel of the mirror about the torsional hinges.

15. The method of claim 14, wherein the second substrate is a single crystalline silicon substrate.

16. The method of claim 8, wherein the etching to form the recessed region and the through-substrate etch are conducted from opposite sides of the second substrate.

17. The method of claim 8, wherein the second substrate is a single crystalline silicon substrate.

18. The method of claim 8, wherein the first thickness is less than the second thickness.

19. The method of claim 18, wherein the third thickness is equal to one-half a difference between the second thickness and the first thickness.