Torsion spring for electro-mechanical switches and a cantilever-type RF micro-electromechanical switch incorporating the torsion spring

• US 6,842,097 B2
• Filed: 05/11/2004
• Issued: 01/11/2005
• Est. Priority Date: 03/12/2001
• Status: Expired due to Fees

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Schmitz, Adele, Hsu, Tsung-Yuan, Loo, Robert
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Rojas, Bernard
• Application Number:
  US10/844,273
• Publication Number:
  US 20040207499A1
• Time in Patent Office: 245 Days
• Field of Search: 335/78, 335/80, 200/181
• US Class Current: 335/78
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01G 5/40 Structural combinations of variable capacitors with other electric elements not covered by this subclass, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01H 1/06 characterised by the shape or structure of the contact-making surface, e.g. grooved
• CPC Class Codes: H01H 1/20 Bridging contacts for circuit breakers H01H73/045
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01P 1/127 Strip line switches

Abstract

A torsion spring for an electro-mechanical switch is presented. The torsion spring comprises a set of tines including at least one tine extending from the free end of the armature of a switch. A terminus portion is rotatably suspended between the tines, and includes a conducting transmission line, at least a portion of which is exposed for electrical contact. The conducting transmission line has a length selected such that the exposed portion of the transmission line forms a circuit between the input and output of the micro-electro-mechanical switch when the micro-electro-mechanical switch is urged into a closed position, with the terminus portion rotating via the tines to form a conformal connection between the exposed portion of the conducting transmission line and the input and output of the switch, thus optimizing the electrical flow therebetween. The switch is also applied to MEMS devices.

Claims

1. A micro-electro-mechanical switch comprising:

a substrate;

an input line on top of the substrate;

an output line on top of the substrate and separated from the input line;

a substrate electrode on top of the substrate, located near but separated from the input line and the output line; and

an armature comprising;

a first beam structural layer having a first end mechanically connected with the substrate and a second end including a set of tines including at least one tine with a terminus portion rotatably suspended therefrom, with the terminus portion including a conducting transmission line positioned over the input and output lines, with the at least a portion of the conducting transmission line exposed for conformal contact with the input and output lines; and

an armature electrode positioned directly above the substrate electrode and suspended on the armature;

an insulating layer positioned between the armature electrode and the substrate electrode to prevent short-circuiting therebetween;

whereby when the switch is actuated into a “

closed”

position, the terminus portion is free to rotate to ensure a conformal contact between the exposed portion of the conducting transmission line and the input and output lines in order to form a circuit therebetween to permit the flow of electricity.

2. A micro-electro-mechanical switch as set forth in claim 1, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

3. A micro-electro-mechanical switch as set forth in claim 2, wherein the tines are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

4. A micro-electro-mechanical switch as set forth in claim 3, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

5. A micro-electro-mechanical switch as set forth in claim 1, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

6. A micro-electro-mechanical switch as set forth in claim 5, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

7. A micro-electro-mechanical switch as set forth in claim 1, wherein the tines are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

8. A micro-electro-mechanical switch as set forth in claim 7, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

9. A micro-electro-mechanical switch as set forth in claim 1, wherein the first beam structural layer is positioned above the armature electrode.

10. A micro-electro-mechanical switch as set forth in claim 9, wherein the insulating layer is formed as a second beam structural layer under the armature electrode, with the first and the second beam structural layers formed of materials selected such that their mechanical and thermal properties provide a desired amount of bowing when the switch is activated.

11. A micro-electro-mechanical switch as set forth in claim 10, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

12. A micro-electro-mechanical switch as set forth in claim 11, wherein the tines are formed of the same material as either the first or the second beam structural layer and the beam structural layers are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

13. A micro-electro-mechanical switch as set forth in claim 12, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

14. A micro-electro-mechanical switch as set forth in claim 13, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

15. A micro-electro-mechanical switch as set forth in claim 14, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

16. A micro-electro-mechanical switch as set forth in claim 15, wherein the tines are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

17. A micro-electro-mechanical switch as set forth in claim 16, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

18. A micro-electro-mechanical switch as set forth in claim 9, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

19. A micro-electro-mechanical switch as set forth in claim 18, wherein the tines are formed of the same material as the first beam structural layer and the beam structural layers are each constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

20. A micro-electro-mechanical switch as set forth in claim 19, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

21. A micro-electro-mechanical switch as set forth in claim 9, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

22. A micro-electro-mechanical switch as set forth in claim 21, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

23. A micro-electro-mechanical switch as set forth in claim 9, wherein the tines are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

24. A micro-electro-mechanical switch as set forth in claim 23, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

25. A micro-electro-mechanical switch as set forth in claim 9, wherein the insulating layer is formed as a layer on the substrate electrode.

26. A micro-electro-mechanical switch as set forth in claim 25, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

27. A micro-electro-mechanical switch as set forth in claim 26, wherein the tines are formed of the same material as the first beam structural layer and the beam structural layers are each constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

28. A micro-electro-mechanical switch as set forth in claim 27, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

29. A micro-electro-mechanical switch as set forth in claim 25, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

30. A micro-electro-mechanical switch as set forth in claim 29, wherein the portion of the conducting transmission line exposed for electrical contact is in the form of a plurality of dimples, with a dimple corresponding to the contact to be made between the input and the output, respectively;

whereby the dimples combined with the rotatable nature of the terminus portion provide a conformal contact between the conducting transmission line and the input and the output to form a circuit therebetween.

31. A micro-electro-mechanical switch as set forth in claim 25, wherein the tines are constructed of a material selected from a group consisting of silicon nitride, Type III-V semiconductor materials, and silicon dioxide.

32. A micro-electro-mechanical switch as set forth in claim 31, wherein the conducting transmission line is formed from a titanium adhesive layer and a gold conductor layer and an anti-diffusion layer therebetween.

33. A torsion spring for a micro-electro-mechanical switch as set forth in claim 1, wherein the set of tines includes a plurality of tines.

34. A torsion spring for a micro-electro-mechanical switch as set forth in claim 1, wherein the set includes two tines.