Switches and switching arrays that use microelectromechanical devices having one or more beam members that are responsive to temperature

• US 6,407,478 B1
• Filed: 08/21/2001
• Issued: 06/18/2002
• Est. Priority Date: 08/21/2000
• Status: Expired due to Term

• Current Assignee: Memscap Incorporated
• Original Assignee: JDS Uniphase Corporation (Lumentum Holdings Inc.)
• Inventors: Wood, Robert L., Agrawal, Vivek
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/935,003
• Publication Number:
  US 20020021053A1
• Time in Patent Office: 301 Days
• Field of Search: 310/307, 310/309
• US Class Current: 310/307
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• CPC Class Codes: H01H 2001/0047 operable only by mechanical latching
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 2061/008 Micromechanical actuator with a cold and a hot arm, coupled together at one end
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

A microelectromechanical device comprises first and second beam members that have respective first ends connected to anchors, and that are also connected together. The first and second beam members are connected to a dielectric tether by a first tether anchor. The microelectromechanical device further comprises a third beam member that has a first end that is connected to an anchor and that is connected to the dielectric tether by a second tether anchor. At least one of the first and the second beam members are configured to elongate when the first and/or the second beam member is heated to a temperature that is greater than a temperature of the third beam member.

Claims

1. A microelectromechanical device, comprising:

a first beam member that has an end that is connected to a first anchor;

a second beam member that has an end that is connected to a second anchor, the second beam member being configured to elongate when the second beam member is heated to a temperature that is greater than a temperature of the first beam member; and

a contact that comprises a first conductive region that connects the first and the second beam members, a second conductive region, and an isolation region that electrically isolates the first conductive region from the second conductive region.

2. The microelectromechanical device of claim 1, wherein the first and the second conductive regions comprise nickel, and the isolation region comprises silicon nitride.

3. The microelectromechanical device of claim 1, further comprising:

a tab attached to the contact.

4. The microelectromechanical device of claim 1, further comprising:

a substrate, wherein the first and the second anchors are attached to the substrate.

5. A microelectromechanical device, comprising:

a first beam member that has an end that is connected to a first anchor;

a second beam member that has an end that is connected to a second anchor;

a third beam member that is connected to the second beam member and has an end that is connected to a third anchor, a respective one of the second and third beam members being configured to elongate when the respective one of the second and third beam members is heated to a temperature that is greater than a temperature of the first beam member; and

a dielectric tether that has a first tether anchor attached thereto that connects the second and the third beam members to the dielectric tether, and a second tether anchor attached thereto that is connected to the first beam member.

6. The microelectromechanical device of claim 5, further comprising:

a tab attached to the dielectric tether.

7. The microelectromechanical device of claim 5, further comprising:

a substrate, wherein the first, the second, and the third anchors are attached to the substrate.

8. The microelectromechanical device of claim 7, wherein the substrate has a trench etched therein that extends under at least a portion of the second and the third beam members.

9. A method of operating a microelectromechanical device, comprising:

providing first and second beam members that are connected to each other and have respective ends that are connected to first and second anchors;

providing a third beam member that has an end that is connected to a third anchor, the third beam member being connected to a second tether anchor;

providing a dielectric tether having a first tether anchor attached thereto that connects the first and the second beam members to the dielectric tether and a second tether anchor attached thereto that connects the third beam member to the dielectric tether; and

generating a current through the first and the second beam members to deflect the dielectric tether from an initial position towards the third beam member.

10. The method of claim 9, further comprising:

terminating the current generated through the first and the second beam members to cause the dielectric tether to deflect towards the initial position.

11. The method of claim 9, wherein the first, the second, and the third anchors are connected to a substrate.

12. A microelectromechanical switch, comprising:

a substrate;

a pair of switch contacts attached to the substrate;

a first actuator that has a first end that is connected to the substrate and that has a contact connected thereto, the first actuator further comprising a first tab attached to the contact, the first actuator being operable to deflect in response to an electrical current; and

a second actuator that has a first end that is connected to the substrate and that has a second tab connected thereto, the second actuator being operable to deflect in response to an electrical current;

wherein the first and the second actuators are positioned such that the contact electrically connects the pair of switch contacts when the first tab engages the second tab between the pair of switch contacts and the second tab, and the contact does not electrically connect the pair of switch contacts when the second tab engages the first tab between the pair of switch contacts and the first tab.

13. The microelectromechanical switch of claim 12, wherein the first and the second actuators each comprise:

a first beam member that has an end that is connected to a first anchor on the substrate; and

a second beam member that has an end that is connected to a second anchor on the substrate, the second beam member being configured to elongate when the second beam member is heated to a temperature that is greater than a temperature of the first beam member.

14. The microelectromechanical switch of claim 13, wherein the contact comprises a first conductive region that connects the first beam member and the second beam member of the first actuator, a second conductive region, and an isolation region that electrically isolates the first conductive region from the second conductive region.

15. The microelectromechanical switch of claim 14, wherein the first and the second conductive regions comprise nickel, and the isolation region comprises silicon nitride.

16. A microelectromechanical switch, comprising:

a substrate;

a first actuator that has an end that is connected to the substrate and that has a first tab connected thereto; and

a second actuator that has an end that is connected to the substrate and that has a second tab connected thereto, the first and second actuators being operable such that the first tab engages the second tab when the first and the second actuators are in a first position, and the first tab is disengaged from the second tab when the first and the second actuators are in a second position;

wherein the first and the second actuators each comprise;

a first beam member that has an end that is connected to a first anchor on the substrate;

a second beam member that has an end that is connected to a second anchor on the substrate;

a third beam member that is connected to the second beam member and that has an end that is connected to a third anchor on the substrate, a respective one of the second and the third beam members being configured to elongate when the respective one of the second and the third beam members is heated to a temperature that is greater than a temperature of the first beam member; and

a dielectric tether that has a first tether anchor attached thereto that connects the second and the third beam members to the dielectric tether, and a second tether anchor attached thereto that connects the first beam member to the dielectric tether.

17. The microelectromechanical switch of claim 16, wherein the first and the second tabs are attached to the second tether anchors connected to the first beam members of the first and the second actuators, respectively.

18. The microelectromechanical switch of claim 16, wherein the substrate has a trench etched therein that extends under at least a portion of the second and the third beam members of one of the first and the second actuators.

19. A method of operating a microelectromechanical switch, comprising:

providing a substrate;

providing a pair of switch contacts that are attached to the substrate;

providing a first actuator that has an end that is connected to the substrate and that has a contact connected thereto, the first actuator further comprising a first tab attached to the contact, the first actuator being operable to deflect in response to an electrical current;

providing a second actuator that has an end that is connected to the substrate and that has a second tab connected thereto, the second actuator being operable to deflect in response to an electrical current;

generating a current through the second actuator to deflect the second actuator away from the pair of switch contacts; and

generating a current through the first actuator to deflect the first actuator away from the pair of switch contacts.

20. The method of claim 19, further comprising:

terminating the current generated through the first actuator to cause the first actuator to deflect towards the pair of switch contacts such that the contact electrically connects the pair of switch contacts;

then

terminating the current generated through the second actuator to cause the second actuator to deflect towards the pair of switch contacts such that the first tab engages the second tab between the pair of switch contacts and the second tab.

21. The method of claim 19, further comprising:

terminating the current generated through the second actuator to cause the second actuator to deflect towards the pair of switch contacts;

then

terminating the current generated through the first actuator to cause the first actuator to deflect towards the pair of switch contacts such that the second tab engages the first tab between the pair of switch contacts and the first tab thereby maintaining separation between the pair of switch contacts and the contact.

22. The method of claim 19, wherein the first and the second actuators each comprise:

a first beam member that has an end that is connected to a first anchor on the substrate; and

a second beam member that has an end that is connected to a second anchor on the substrate, the second beam member being configured to elongate when the second beam member is heated to a temperature that is greater than a temperature of the first beam member.

23. The method of claim 22, wherein generating the current through the first actuator comprises:

generating the current through the second beam member of the first actuator to heat the second beam member of the first actuator and to cause localized annealing in the second beam member of the first actuator; and

wherein generating the current through the second actuator comprises;

generating the current through the second beam member of the second actuator to heat the second beam member in the second actuator and to cause localized annealing in the second beam member of the second actuator.

24. A method of operating a microelectromechanical switch, comprising:

providing a substrate;

providing a first actuator that has an end that is connected to the substrate and that has a first tab connected thereto, the first actuator being operable to deflect in response to an electrical current;

providing a second actuator that has an end that is connected to the substrate and that has a second tab connected thereto, the second actuator being operable to deflect in response to an electrical current;

wherein the first and the second actuators each comprise;

first and second beam members that are connected to each other and that have respective ends that are connected to first and second anchors on the substrate;

a third beam member that has an end that is connected to a third anchor on the substrate; and

a dielectric tether having a first tether anchor attached thereto that connects the first and the second beam members to the dielectric tether and a second tether anchor attached thereto that connects the third beam member to the dielectric tether;

generating a current through the first and the second beam members of the first actuator to deflect the dielectric tether of the first actuator from an initial position towards the third beam member of the first actuator; and

generating a current through the first and the second beam members of the second actuator to deflect the dielectric tether of the second actuator from an initial position towards the third beam member of the second actuator.

25. The method of claim 24, further comprising:

terminating the current generated through the first and the second beam members of the first actuator to cause the dielectric tether of the first actuator to deflect towards the initial position; and

terminating the current generated through the first and the second beam members of the second actuator to cause the dielectric tether of the second actuator to deflect towards the initial position such that the second tab engages the first tab.

26. The method of claim 25, wherein the first tab and the second tab are attached to the second tether anchors connected to the third beam members of the first and the second actuators, respectively.

27. The method of claim 24, wherein the substrate has a trench etched therein that extends under at least a portion of the first and the second beam members of one of the first and the second actuators.

28. A switching array, comprising:

a substrate;

a row signal path on the substrate that comprises a plurality of first switch contacts;

a column signal path on the substrate that comprises a plurality of second switch contacts;

a plurality of first actuators, a respective one of the plurality of first actuators having an end that is connected to the substrate and having a contact connected thereto, the respective one of the plurality of first actuators further comprising a first tab attached to the contact, the respective one of the plurality of first actuators being operable to deflect in response to an electrical current; and

a plurality of second actuators, a respective one of the plurality of second actuators having an end that is connected to the substrate and having a second tab connected thereto, the respective one of the plurality of second actuators being operable to deflect in response to an electrical current;

wherein the respective one of the plurality of first actuators and the respective one of the plurality of second actuators are positioned such that the contact electrically connects a respective one of the first plurality of switch contacts to a respective one of the second plurality of switch contacts when the first tab engages the second tab between the respective one of the first plurality of switch contacts and the respective one of the second plurality of switch contacts and the second tab, and the contact does not electrically connect the respective one of the first plurality of switch contacts to the respective one of the second plurality of switch contacts when the second tab engages the first tab between the respective one of the first plurality of switch contacts and the respective one of the second plurality of switch contacts and the first tab.

29. The switching array of claim 28, wherein the respective one of the plurality of first actuators and the respective one of the plurality of second actuators each comprise:

a first beam member that has an end that is connected to a first anchor on the substrate; and

a second beam member that has an end that is connected to a second anchor on the substrate, the second beam member being configured to elongate when the second beam member is heated to a temperature that is greater than a temperature of the first beam member.

30. The switching array of claim 29, wherein the contact comprises a first conductive region that connects the first beam member and the second beam member of the respective one of the plurality of first actuators, a second conductive region, and an isolation region that electrically isolates the first conductive region from the second conductive region.

31. The switching array of claim 30, wherein the first and the second conductive regions comprise nickel, and the isolation region comprises silicon nitride.

32. The switching array of claim 28, wherein the respective one of the plurality of first actuators and the respective one of the plurality of second actuators each comprise:

a first beam member that has an end that is connected to a first anchor on the substrate;

a second beam member that has an end that is connected to a second anchor on the substrate;

a third beam member that is connected to the second beam member and that has an end that is connected to a third anchor on the substrate, a respective one of the second and the third beam members being configured to elongate when the respective one of the second and the third beam members is heated to a temperature that is greater than a temperature of the first beam member; and

a dielectric tether that has a first tether anchor attached thereto that connects the second and the third beam members to the dielectric tether, and a second tether anchor attached thereto that connects the first beam member to the dielectric tether.

33. The switching array of claim 32, wherein the contact comprises the second tether anchor connected to the first beam member of the respective one of the plurality of first actuators.

34. The switching array of claim 32, wherein the substrate has a trench etched therein that extends under at least a portion of the second and the third beam members of one of the respective one of the plurality of first actuators and the respective one of the plurality of second actuators.

35. The switching array of claim 28, further comprising:

a plurality of first diodes, a respective one of the plurality of first diodes being connected to the respective one of the plurality of first actuators; and

a plurality of second diodes, a respective one of the plurality of second diodes being connected to the respective one of the plurality of second actuators.

36. The switching array of claim 28, wherein the substrate comprises a first substrate, the switching array further comprising:

a second substrate connected to the first substrate, the second substrate comprising;

a first conductive path that is electrically connected to the row signal path; and

a second conductive path that is electrically connected to the column signal path.

37. The switching array of claim 36, wherein the second substrate is connected to the first substrate via solder bumps.

38. The switching array of claim 36, wherein the second substrate comprises a material selected from the group of materials comprising ceramic, silicon, and FR4.