Switches for shorting during MEMS etch release

• US 20080160251A1
• Filed: 12/29/2006
• Published: 07/03/2008
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Cummings, William J.
• Granted Patent: US 7,556,981 B2
• Time in Patent Office: Days
• US Class Current: 428/119
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00579 Avoid charge built-up
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: Y10T 428/24174 including sheet or component perpendicular to plane of web or sheet

Abstract

A MEMS (Microelectromechanical system) device is described. The device includes a first layer on a substrate, and a sacrificial layer on or over the first layer, the first sacrificial layer being configured to be removed in a removal procedure. The device also includes a second layer on or over the first sacrificial layer, where the second layer is spaced apart from the first layer, and a shorting element electrically connecting the first and second layers, where at least a portion of the shorting element is removable in the removal procedure.

Claims

1. A method of manufacturing a MEMS (microelectromechanical system) device, the method comprising:

forming a first layer on a substrate;

forming a sacrificial layer on or over the first layer, the sacrificial layer configured to be removed in a removal procedure;

forming a second layer on or over the first sacrificial layer, wherein the second layer is spaced apart from the first layer; and

forming a shorting element electrically connecting the first and second layers, wherein at least a portion of the shorting element is removable in the removal procedure.

2. The method of claim 1, additionally comprising performing the removal procedure.

3. The method of claim 2, wherein the removal procedure comprises opening the shorting element, wherein the first and second layers become electrically isolated.

4. The method of claim 3, wherein the first sacrificial layer is removed prior to opening the shorting element.

5. The method of claim 2, wherein performing the removal procedure comprises substantially simultaneously subjecting the sacrificial layer and the shorting element to one or more common manufacturing steps.

6. The method of claim 2, wherein performing the removal procedure comprises etching.

7. The method of claim 2, wherein forming the shorting element comprises forming a second sacrificial layer, and wherein the removal procedure comprises etching at least one of the first and second sacrificial layers.

8. The method of claim 7, wherein at least part of the first and second sacrificial layers are formed simultaneously.

9. The method of claim 1, further comprising forming an interferometric light modulation cavity between the first and second layers.

10. The method of claim 1, wherein the substrate comprises glass.

11. The method of claim 1, wherein the shorting element comprises at least one of molybdenum, tungsten, and titanium.

12. The method of claim 1, wherein the sacrificial layer is configured to be removed with an etchant comprising XeF₂.

13. The method of claim 1, further comprising:

forming a first structure comprising the first and second layers, and a first etching agent access passage; and

forming a second structure comprising the shorting element, and a second etching agent access passage, wherein the first etching agent access passage is configured to allow the first sacrificial layer to be removed before the shorting element is opened.

14. The method of claim 1, wherein removing the sacrificial layer induces electrical charge build-up.

15. The method of claim 1, further comprising:

forming an array of MEMS elements, the array comprising a plurality of addressing lines;

forming at least one connection pad; and

forming a plurality of switches configured to selectively connect two or more of the addressing lines to the connection pad.

16. The method of claim 15, further comprising forming one or more of the plurality of switches an area designated for occupation by a driver circuit.

17. A MEMS (Microelectromechanical system) device comprising:

a first layer on a substrate;

a sacrificial layer on or over the first layer, the first sacrificial layer configured to be removed in a removal procedure;

a second layer on or over the first sacrificial layer, wherein the second layer is spaced apart from the first layer; and

a shorting element electrically connecting the first and second layers, wherein at least a portion of the shorting element is removable in the removal procedure.

18. The device of claim 17, wherein the sacrificial layer and the shorting element are configured such that during the removal procedure, the sacrificial layer is removed prior to the shorting element being opened.

19. The device of claim 17, wherein the shorting element comprises sacrificial material.

20. The device of claim 17, further comprising an interferometric light modulation cavity between the first and second layers.

21. The device of claim 17, wherein the substrate comprises glass.

22. The device of claim 17, wherein the shorting element comprises molybdenum.

23. The device of claim 17, wherein the first layer and the second layer are part of a first structure, and the shorting element is part of a second structure, wherein the first structure comprises a first etching agent access passage, the second structure comprises a second etching agent access passage, and the first etching agent access passage is configured to allow the first sacrificial layer to be removed before the portion of the shorting element is disconnected.

24. The device of claim 17, further comprising:

an array of MEMS elements, the array comprising a plurality of addressing lines;

at least one connection pad; and

a plurality of switches configured to selectively connect two or more of the addressing lines to the connection pad.

25. The device of claim 24, further comprising a driver area, the driver circuit located on or over the plurality of switches.

26. A MEMS (Microelectromechanical system) device comprising:

an array of MEMS elements comprising first and second conductive layers; and

means for electrically connecting and disconnecting said first and second layers during an etching process.

27. The device of claim 26, wherein the connecting and disconnecting means comprises at least a portion of a shorting element, wherein the portion electrically connects the first and second layers and is removable in the etching process so as to disconnect the first and second layers.

28. The device of claim 27, wherein the first and second layers are a sacrificial material.