MEMS device members having portions that contact a substrate and associated methods of operating

• US 6,496,351 B2
• Filed: 03/30/2001
• Issued: 12/17/2002
• Est. Priority Date: 12/15/1999
• Status: Expired due to Term

• Current Assignee: Computer Circuit Operations LLC
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Hill, Edward A., Mahadevan, Ramaswamy
• Primary Examiner(s): Dinkins, Anthony
• Application Number:
  US09/822,128
• Publication Number:
  US 20020018334A1
• Time in Patent Office: 627 Days
• Field of Search: 361/277, 361/278, 361/281-282, 361/299.5, 361/298.2, 361/298.4, 361/298.5, 361/290, 29/254.1, 29/254.2
• US Class Current: 361/278
• CPC Class Codes: B81B 2201/032 Bimorph and unimorph actuators, e.g. piezo and thermo
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: F03G 7/06 using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like using thermal expansion of non-vaporising liquids F01K
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2059/0063 with stepped actuation, e.g. actuation voltages applied to different sets of electrodes at different times or different spring constants during actuation
• CPC Class Codes: H01H 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 2059/0081 with a tapered air-gap between fixed and movable electrodes
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 61/02 wherein the thermally-sensitive member is heated indirectly, e.g. resistively, inductively

Abstract

MEMS devices include a substrate, an anchor attached to the substrate, and a multilayer member attached to the anchor and spaced apart from the substrate. The multilayer member can have a first portion that is remote from the anchor and that curls away from the substrate and a second portion that is adjacent the anchor that contacts the substrate. Related methods are also disclosed.

Claims

1. A microelectromechanical system (MEMS) device comprising:

a substrate;

an anchor attached to the substrate; and

a multilayer member attached to the anchor and spaced apart from the substrate, the multilayer member having a first portion that is remote from the anchor and that curls away from the substrate and a second portion that is adjacent to the anchor and that contacts the substrate.

2. A MEMS device according to claim 1, wherein the multilayer member extends in a direction, the MEMS device further comprising:

a connecting member having a portion that extends in the direction and that attaches the anchor to the multilayer member.

3. A MEMS device according to claim 2, wherein the connecting member comprises a serpentine shaped connecting member.

4. A MEMS device according to claim 2, wherein the connecting member is attached to a third portion of the multilayer member that is closer to the first portion than the second portion.

5. A MEMS device according to claim 2, wherein the connecting member is attached to a third portion of the multilayer member that is closer to the second portion than the first portion.

6. A MEMS device according to claim 1, wherein the anchor comprises a first anchor, the MEMS device further comprising:

a second anchor attached to the substrate and the multilayer member that defines an anchor axis that passes through the first and second anchors, wherein the second portion contacts the substrate at a point between the anchor axis and the first portion.

7. A MEMS device according to claim 1, wherein the anchor comprises a first anchor, the MEMS device further comprising:

a second anchor attached to the substrate and the multilayer member that defines an anchor axis that passes through the first and second anchors, wherein the second portion contacts the substrate inline with the anchor axis.

8. A MEMS device according to claim 1, wherein the multilayer member comprises:

a first layer adjacent to the substrate having a first coefficient of thermal expansion; and

a second layer on the first layer opposite the substrate having a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion, wherein the multilayer member contacts the substrate in response to heating the first and second layers.

9. A MEMS device according to claim 8 further comprising:

a heater that heats the first and second layers of the multilayer member.

10. A MEMS device according to claim 1, wherein the multilayer member comprises:

a first layer adjacent to the substrate having a first coefficient of thermal expansion; and

a second layer on the first layer opposite the substrate having a second coefficient of thermal expansion that is greater than the first coefficient of thermal expansion, wherein the multilayer member contacts the substrate in response to cooling at least one of the first and second layers.

11. A MEMS device according to claim 9 further comprising:

a thermo-electric cooling device that cools the first and second layers of the multilayer member.

12. A MEMS device according to claim 1, wherein the multilayer member comprises:

a first layer adjacent to the substrate having a first tensile stress; and

a second layer on the first layer opposite the substrate having a second tensile stress that is greater than the first tensile stress, wherein the multilayer member contacts the substrate in response to a difference between the first tensile stress and the second tensile stress.

13. A MEMS device according to claim 1 further comprising:

a first plate on the substrate; and

a second plate on the multilayer member, wherein the first portion moves relative to the substrate in response to a voltage applied between the first and second plates.

14. A MEMS device according to claim 1 further comprising:

an insulator on the substrate where the second portion contacts the substrate.

15. A MEMS device according to claim 1, wherein the first portion is separated from the substrate by a first distance when the multilayer member is in a first position;

and

wherein the first portion is separated from the substrate by a second distance that is less than the first distance when the multilayer member is in a second position.

16. A MEMS device according to claim 1 further comprising:

a second anchor attached to the substrate and the first portion of the multilayer member at a point that is closer to the first portion than the second portion.

17. A MEMS device according to claim 16 further comprising:

a via opposite the second portion of the multilayer member, wherein the second portion of the multilayer member contacts the via when in the first position.

18. A MEMS device according to claim 16 further comprising:

a receptacle on the substrate opposite the second portion of the multilayer member; and

a protrusion from the second portion, wherein the protrusion is coupled to the receptacle when the multilayer member is in the first position.

19. A MEMS device according to claim 18, wherein the protrusion is separated from the receptacle when the multilayer member is in the second position.

20. A MEMS device according to claim 19, wherein the second portion moves away from the substrate in response to a thermal effect.

21. A method of actuating a microelectromechanical system (MEMS) device comprising:

changing the temperature associated with the multilayer member to reduce a distance between the multilayer member and the substrate;

allowing a portion of the multilayer member to contact the substrate; and

then applying a voltage between the multilayer member and the substrate to adjust the distance therebetween.

22. A method according to claim 21, wherein the act of changing comprises one of heating and cooling the multilayer member.

23. A method according to claim 21, wherein the act of applying is followed by:

changing a temperature associated with the multilayer member to increase the distance between the multilayer member and the substrate.

24. A microelectromechanical system (MEMS) device comprising:

a substrate;

an anchor attached to the substrate; and

a multilayer member attached to the anchor and spaced apart from the substrate, the multilayer member is configured so as to contact the substrate at an intermediate point thereof.

25. A MEMS device according to claim 24, wherein the multilayer member extends in a direction, the MEMS device further comprising:

a connecting member having a portion that extends in the direction and that attaches the anchor to the multilayer member.

26. A MEMS device according to claim 25, wherein the connecting member comprises a serpentine shaped connecting member.

27. A MEMS device according to claim 25, wherein the connecting member is attached to a portion of the multilayer member remote from the anchor and that is adjacent to the intermediate point that contacts substrate.

28. A method of positioning a multilayer member on a substrate that is attached thereto via an anchor, the method comprising:

curling a first portion of the multilayer member that is remote from the anchor away from the substrate to a first position that is spaced-apart from the substrate by a first distance and moving a second portion of the multilayer member that is adjacent to the anchor to contact the substrate; and

then

moving the first portion to a second position that is spaced apart from the substrate by a second distance that is less than the first distance.

29. A method according to claim 28, wherein the first portion is moved to the first position via a tensile force between at least two layers of the multilayer member.

30. A method according to claim 28, wherein the first portion is moved to the second position via a thermal effect between at least two layers of the multilayer member.

31. A method according to claim 28 further comprising:

maintaining the second distance without contacting the substrate.