MEMS ANCHORS

• US 20120200906A1
• Filed: 04/18/2012
• Published: 08/09/2012
• Est. Priority Date: 10/27/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Wu, Joyce H., Andersson, Mark B., Steyn, Jasper Lodewyk
• Granted Patent: US 8,599,463 B2
• Time in Patent Office: Days
• US Class Current: 359/230
• CPC Class Codes: B81B 1/00 Devices without movable or flexible elements, e.g. microcapillary devices
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

The invention relates to an improved apparatus and method for the design and manufacture of MEMS anchoring structures for light modulators in order to address the stresses of beams mounted on them.

Claims

1. A MEMS device comprising:

a substrate having a primary, horizontal face, upon which the MEMS device is formed; and

a first beam suspended over the substrate by an anchor, the anchor including;

a first elevating portion coupled to the primary face of the substrate;

a first substantially horizontal shelf portion elevated over the substrate by the first elevating portion; and

a first non-horizontal anchor stiffening portion, from which the first beam extends, extending from the shelf portion.

2. The MEMS device of claim 1, comprising a shutter connected to the first beam.

3. The device of claim 2, comprising a second anchor and a second beam, the second beam being connected to the second anchor and the shutter.

4. The MEMS device of claim 3, wherein the second anchor includes:

a second elevating portion coupled to the primary face of the substrate;

a second substantially horizontal shelf portion elevated over the substrate by the second elevating portion; and

a second non-horizontal anchor stiffening portion, from which the second beam extends, extending from the second substantially horizontal shelf portion.

5. The MEMS device of claim 1, wherein the first non-horizontal anchor stiffening portion comprises at least two unit normal vectors that are substantially different.

6. The MEMS device of claim 5, wherein at least two non-horizontal anchor stiffening portions including the first non-horizontal anchor stiffening portion are coupled to each other as well as to the first substantially horizontal shelf portion;

and wherein the normal vectors of the at least two non-horizontal anchor stiffening portions are substantially different.

7. The MEMS device of claim 1, wherein one or more substantially horizontal shelf portions including the first substantially horizontal shelf portion are further coupled to one or more non-horizontal anchor stiffening portions including the first non-horizontal anchor stiffening portion.

8. The MEMS device of claim 1, wherein the first elevating portion forms a closed space or a well.

9. The MEMS device of claim 1, wherein the suspended first beam has a height that is at least 1.4 times its width.

10. The MEMS device of claim 1, wherein the first non-horizontal anchor stiffening portion is made from the same material as the first substantially horizontal shelf portion.

11. The MEMS device of claim 1, wherein the first beam is made from a different material than the first substantially horizontal shelf portion.

12. The MEMS device of claim 1, wherein the first beam is coupled to the first substantially horizontal shelf portion.

13. The MEMS device of claim 1, wherein two or more beams including the first beam extend from the anchor.

14. The MEMS device of claim 1, wherein the first non-horizontal anchor stiffening portion extends above the first substantially horizontal shelf portion.

15. The MEMS device of claim 1, wherein the first non-horizontal anchor stiffening portion extends below the first substantially horizontal shelf portion.

16. The MEMS device of claim 1, wherein the beam is situated on the side of the first substantially horizontal shelf portion opposite to the substrate.

17. The MEMS device of claim 1, wherein the first non-horizontal anchor stiffening portion is substantially perpendicular to the first substantially horizontal shelf portion.

18. A method of manufacturing a MEMS device using a structure made by a sidewall process, comprising:

forming a mold on a substrate, wherein the mold includes a lower horizontal surface, an upper horizontal surface and a wall;

depositing a beam material on the lower horizontal surface and the wall of the mold;

removing at least a portion of the beam material deposited on the lower horizontal surface of the mold while leaving the majority of the beam material deposited on the wall of the mold in place to form a first compliant beam; and

removing the mold.

19. The method of claim 18, further comprising forming a shutter coupled to the first compliant beam and releasing the shutter when removing the mold.

20. The method of claim 19, further comprising forming a first anchor structure including a first elevating portion, a first horizontal shelf portion, and a first non-horizontal anchor stiffening portion, the first anchor structure being coupled to the first compliant beam.

21. The method of claim 20, wherein the first elevating portion is manufactured from a first mold material.

22. The method of claim 20, wherein the first non-horizontal anchor stiffening portion is manufactured from a second mold material.

23. The method of claim 20, wherein the first anchor structure and the first compliant beam are manufactured from the same material, at least two different materials, or a composite material.

24. The method of claim 20, further comprising forming a second compliant beam coupled to the shutter.

26. A MEMS device comprising:

a substrate including a surface;

a shutter suspended over the surface, the shutter including a first side and second side, the second side being substantially opposite to the first side along an axis of movement of the shutter;

a first actuator coupled to the first side of the shutter via a single first compliant beam; and

a second actuator coupled to the second side of the shutter via a single second compliant beam.

25. The method of claim 26, further comprising forming a second anchor structure including a second elevating portion, a second horizontal shelf portion, and second non-horizontal anchor stiffening portion, the second anchor structure being coupled to the second compliant beam.

27. The MEMS device of claim 26, wherein the first compliant beam includes an attachment point to the shutter that is substantially along the axis of movement of the shutter.

28. The MEMS device of claim 27, wherein the second compliant beam includes an attachment point to the shutter that is substantially along the axis of movement of the shutter.

29. The MEMS device of claim 26, wherein the shutter is in a first position along the axis of movement in response to the first actuator being in a relaxed state and the second actuator being in an actuated state.

30. The MEMS device of claim 26, wherein the shutter is in a second position along the axis of movement in response to the first actuator being in an actuated state and the second actuator being in a relaxed state.

31. The MEMS device of claim 26, wherein the shutter includes one or more shutter apertures.

32. The MEMS device of claim 26, wherein the first compliant beam includes a first electrode.

33. The MEMS device of claim 32, wherein the second compliant beam includes a second electrode.

34. The MEMS device of claim 26, wherein the surface includes an aperture for allowing the passage of light over which the shutter is at least partially suspended.

35. A MEMS device comprising:

a substrate including a surface;

a shutter suspended over the surface, the shutter including a first side and second side, the second side being substantially opposite to the first side along an axis of movement of the shutter;

a first means for moving the shutter coupled to the first side of the shutter via a single first compliant beam; and

a second means for moving the shutter coupled to the second side of the shutter via a single second compliant beam.

36. The MEMS device of claim 35, wherein the first compliant beam includes an attachment point to the shutter that is substantially along the axis of movement of the shutter.

37. The MEMS device of claim 36, wherein the second compliant beam includes an attachment point to the shutter that is substantially along the axis of movement of the shutter.

38. The MEMS device of claim 35, wherein the shutter is in a first position along the axis of movement in response to the first means for moving the shutter being in a relaxed state and the second means for moving the shutter being in an actuated state.

39. The MEMS device of claim 35, wherein the shutter is in a second position along the axis of movement in response to the first means for moving the shutter being in an actuated state and the second means for moving the shutter being in a relaxed state.

40. The MEMS device of claim 35, wherein the shutter includes one or more shutter apertures.

41. The MEMS device of claim 35, wherein the first compliant beam includes a first electrode.

42. The MEMS device of claim 41, wherein the second compliant beam includes a second electrode.

43. The MEMS device of claim 35, wherein the surface includes an aperture for allowing the passage of light over which the shutter is at least partially suspended.