Micro electrical mechanical system (MEMS) tuning using focused ion beams

• US 6,922,118 B2
• Filed: 11/01/2002
• Issued: 07/26/2005
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Kubena, Randall L., Joyce, Richard J.
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US10/286,375
• Publication Number:
  US 20040085159A1
• Time in Patent Office: 998 Days
• Field of Search: 333186-188, 333/200, 310/312, 438/712, 204/192.34, 204/298.36
• US Class Current: 333/188
• CPC Class Codes: H03H 3/0077 by tuning of resonance frequency

Abstract

A method for tuning an electro-mechanical device such as a MEMS device is disclosed. The method comprises operating a MEMS device in a depressurized system and using FIB micromachining to remove a portion of the MEMS device. Additionally, a method for tuning a plurality of MEMS devices by depositing an active layer and then removing a portion of the active layer using FIB micromachining. Also, a method for tuning a MEMS device and vacuum packaging the MEMS device in situ are provided.

Claims

1. A method for tuning an electro-mechanical device having a resonant frequency greater than 1 MHz, comprising the steps of:

providing a specimen chamber;

providing a source in the specimen chamber which emits a focused ion beam;

placing the electro-mechanical device in the specimen chamber;

depressurizing the specimen chamber;

operating the electro-mechanical device;

directing the focused ion beam at the operating electro-mechanical device to ablate a portion of the electro-mechanical device; and

measuring an output frequency of the electro-mechanical device during said directing step.

2. The method of claim 1, wherein the step of depressurizing the specimen chamber provides depressurizing the specimen chamber to a pressure no greater than 10-4 Torr.

3. The method of claim 1, wherein the focused ion beam has a beam current in the range of 1 picoamp to 1 microamp.

4. The method of claim 1, wherein the portion of the focused ion beam contacting the electro-mechanical device has a beam diameter of 5 nanometers to 1000 nanometers.

5. The method of claim 1, wherein the focused ion beam is comprised of a member selected from the group consisting of gallium, silicon, aluminum, copper, boron, and germanium.

6. The method of claim 5, wherein the focused ion beam is comprised of gallium.

7. The method of claim 6, wherein the focused ion beam has energy in the range of 30 keV-50 keV.

8. The method of claim 1, wherein the step of operating the electro-mechanical device provides acoustically operating the electro-mechanical device.

9. The method of claim 1, wherein the electro-mechanical device is a resonator having an adjustable resonant frequency.

10. The method of claim 9, wherein the resonator further comprises tuning pads, the step of directing the focused ion beam comprising a step of ablating the pads.

11. The method of claim 10, wherein the step of ablating the tuning pads tunes the resonant frequency of the resonator.

12. The method of claim 9, wherein the resonator is comprised of a member selected from the group consisting of silicon, aluminum-nitride, silicon-carbide, gallium-nitride, and quartz.

13. The method of claim 1, wherein the step of operating the electro-mechanical device provides electrically operating the electro-mechanical device.

14. The method of claim 1, wherein the electro-mechanical device is a MEMS device.

15. An apparatus for tuning a electro-mechanical device having a resonant frequency greater than 1 MHz, the apparatus comprising:

a specimen chamber;

a focused ion beam located in the specimen chamber and directed at the electro-mechanical device;

power means for providing power to the electro-mechanical device; and

measuring means to measure the output frequency of the electro-mechanical device while the electro-mechanical device is powered by the power means.

16. The apparatus of claim 15, wherein the power means comprises a circuit card.

17. The apparatus of claim 15, wherein the power means comprises a piezoelectric element.

18. The apparatus of claim 15, wherein the power means comprises a wafer probe card.

19. The apparatus of claim 15, further comprising a shuttle and wafer bonder for packaging the electro-mechanical device in situ.

20. The apparatus of claim 15, wherein the electro-mechanical device is a resonator.

21. The apparatus of claim 20, further comprising an active layer deposited on the resonator for detecting chemical and biological agents.

22. The apparatus of claim 20, wherein the resonator is comprised of a member selected from the group of silicon, aluminum-nitride, silicon-carbide, gallium-nitride, quartz.

23. The apparatus of claim 15, wherein the electro-mechanical device is a MEMS device.