Multi-dimensional precision micro-actuator

• US 5,179,499 A
• Filed: 04/14/1992
• Issued: 01/12/1993
• Est. Priority Date: 04/14/1992
• Status: Expired due to Term

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Yao, Jun J., MacDonald, Noel C.
• Primary Examiner(s): Griffin, Donald
• Application Number:
  US07/868,102
• Time in Patent Office: 273 Days
• Field of Search: 156/628, 156/630, 361/311-313, 340/870.37
• US Class Current: 361/313
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 10/04 Fine scanning or positioning
• CPC Class Codes: H01H 1/0094 Switches making use of nanoelectromechanical systems [NEMS]
• CPC Class Codes: H01H 2001/0068 with multi dimensional movement, i.e. the movable actuator performing movements in at least two different directions
• CPC Class Codes: H01H 2001/0078 with parallel movement of the movable contact relative to the substrate
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

Mechanically movable microstructure fabricated from a single crystal such as silicon and actuator structures for providing a high degree of controlled, precision motion of nanometer-scale.

Claims

1. A precision microactuator for movable microstructures, comprising:

a beam having a longitudinal axis and having a first fixed end and a second remote end;

at least one pair of opposed capacitor plates in said beam and dividing said beam into relatively movable axially aligned, longitudinal segments; and

means for applying a potential across said plates to cause said relatively movable segments to move with respect to each other to cause said remote end of said beam to move along said longitudinal axis with respect to said fixed end to vary the length of the beam.

2. The actuator of claim 1, wherein said at least one pair of capacitor plates comprises a plurality of spaced pairs of capacitor plates spaced along said beam and dividing said beam into a corresponding plurality of relatively movable longitudinal segments.

3. The actuator of claim 1, further including flexible spring bias means connected to said plates.

4. The actuator of claim 3, wherein said spring bias means comprises end spacer means between said plates.

5. The actuator of claim 3, wherein said spring bias means comprises connector means connected to said beam segments.

6. The actuator of claim 3, wherein said spring bias means comprises electrically insulating end spacer means between said plates.

7. The actuator of claim 3, wherein said spring bias means comprises electrically conductive connector means connected to said beam segments.

8. The actuator of claim 7, wherein said spring bias means further includes electrically insulating flexible end spacer means between said plates.

9. The actuator of claim 1, wherein said beam and capacitor plates form a cantilevered microstructure within a cavity formed in an integrated circuit wafer.

10. The actuator of claim 9, wherein said means for applying a potential across said plates includes electrically conductive connector means connected between selected beam segments and electrical circuit means on said wafer.

11. The actuator of claim 10, wherein said electrically conductive connector means comprises flexible connector arms which mechanically support and spring bias said microstructure.

12. The actuator of claim 9, wherein said at least one pair of capacitor plates comprises a plurality of pairs of capacitor plates spaced along said beam and dividing said beam into a corresponding plurality of relatively movable longitudinal segments.

13. The actuator of claim 12, wherein said means for applying a potential across said plates comprises electrically conductive connector means interconnecting selected beam segments.

14. The actuator of claim 12, wherein said means for applying a potential across said plates comprises electrically conductive connector means connected between selected beam segments and said wafer.

15. The actuator of claim 1 wherein said beam and capacitor plates are fabricated from a single-crystal electrically conductive substrate to form a cantilevered microstructure, the beam and capacitor plates being of the same material as the substrate.

16. The actuator of claim 15, further including a layer of electrically insulating material on selected surface of said capacitor plates.

17. The actuator of claim 16, further including flexible spring bias means fabricated from said electrically insulating material and connected between opposed capacitor plates for maintaining said plates in a predetermined spaced relationship.

18. The actuator of claim 17, further including electrically conductive connector means connected to corresponding segments of said beam, said connector means forming a part of said cantilevered microstructure.

19. The actuator of claim 18, wherein said connector means are fabricated from the same material as the substrate.

20. The actuator of claim 18, wherein said connector means are flexible and provide additional spring bias means for maintaining said plates in said predetermined spaced relationship.

21. The actuator of claim 15, wherein said substrate is single crystal silicon.

25. The actuator of claim 1, further including:

a plurality of beams each having a first fixed end and a second remote end and at least one pair of opposed capacitor plates in each of said beam to divide each beam into relatively movable, axially aligned, longitudinal segments, said second ends of said beams being connected to a common beam area; and

means for applying potentials across selected pairs of opposed capacitor plates to vary the lengths of corresponding beams and to controllably move said common area.

26. The actuator of claim 25, wherein said plurality of beams extend radially outwardly in a common plane from said common area.

27. The actuator of claim 25, further including substrate means, said first fixed ends of said beams being mounted on said substrate and said common beam area being movable with respect to said substrate.

28. The actuator of claim 27, further including opposed upper and lower nanometer-scale tip means incorporated in said common area and on said substrate, respectively, in vertical axial alignment, movement of said common area moving said upper tip means with respect to said lower tip means.

29. The actuator of claim 27, further including switch means mounted on said common area and on said substrate, whereby motion of said common area operates said switch means.

30. The actuator of claim 27, wherein said means applying potentials across selected pairs of opposed capacitor plates includes integrated control circuit means on said substrate.

31. The actuator of claim 27 wherein said means applying potentials across selected pairs of opposed capacitor plates includes flexible electrically conductive connector means extending between said substrate and selected beam segments.

32. The actuator of claim 27, wherein said at least one pair of opposed capacitor plates in each beam comprises plural spaced pairs of capacitor plates spaced along each beam and dividing the beam into a corresponding plurality of relatively movable longitudinal segments.

33. The actuator of claim 32, further including flexible spring bias means urging each pair of capacitor plates toward a predetermined spaced relationship.

34. The actuator of claim 33, wherein said flexible spring bias means includes spacer means connected between opposed plates of each said pair of capacitor plates.

35. The actuator of claim 33, wherein said flexible spring bias means includes electrically conductive connector means connected to selected beam segments.

36. The actuator of claim 1, wherein said capacitor plates are electrically conductive opposed, generally concave plates having facing generally concave surfaces.

37. The actuator of claim 36, further including insulator means covering said facing surfaces, said insulator means extending beyond said plates at opposite ends thereof to form flexible spring-biased spacers for said capacitor plates.

38. The actuator of claim 1, further including first switch means secured on said remote end of said beam for relative motion with respect to a second switch means.

22. The actuator of claim 22, further including a layer of electrically insulating nitride on selected surfaces of said capacitor plates.

23. The actuator of claim 22, further including spring bias means fabricated from said electrically insulating nitride material and connected to bias said capacitor plates toward a predetermined spaced relationship.

24. The actuator of claim 23, further including flexible, electrically conductive connector means fabricated from said single crystal silicon substrate material and providing electrical connections to said capacitor plates.