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

• US 20040085159A1
• Filed: 11/01/2002
• Published: 05/06/2004
• 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.
• Granted Patent: US 6,922,118 B2
• Time in Patent Office: Days
• US Class Current: 333/188
• CPC Class Codes: H03H 3/0077 by tuning of resonance frequency

Abstract

A method for tuning an electromechanical 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 electromechanical 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 electromechanical device in the specimen chamber;

depressurizing the specimen chamber;

operating the electromechanical device;

directing the focused ion beam at the operating electromechanical device to ablate a portion of the electromechanical device; and

measuring an output frequency of the electromechanical 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 electromechanical 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 1, wherein the electromechanical device is a resonator having an adjustable resonant frequency.

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

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

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

10. The method of claim 6, 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 6, wherein the resonator is comprised of a member selected from the group consisting of silicon, aluminum-nitride, silicon-carbide, gallium-nitride, and quartz.

12. The method of claim 9, wherein the focused ion beam has energy in the range of 30 keV-50 keV.

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

14. The method of claim 1, wherein the electromechanical device is a MEMS device.

15. A method for tuning electromechanical devices using focused ion beam (FIB) micromachining, comprising the steps of:

providing a plurality of electromechanical devices each electro-mechanical device having an adjustable resonant frequency;

providing a focused ion beam;

depositing an active layer on each electromechanical device of the plurality of electro-mechanical devices, the active layer allowing detection of chemical and biological agents; and

tuning electromechanical devices of the plurality of electromechanical devices with the focused ion beam.

16. The method of claim 15, wherein the step of tuning is performed by removing portions of the electromechanical device with the focused ion beam.

17. The method of claim 15, wherein the step of tuning is performed by removing portions of the active layer with the focused ion beam.

18. The method of claim 15, wherein each electromechanical device of the plurality of electromechanical devices has a resonant frequency greater than 1 MHz.

19. The method of claim 15, wherein the active layer is comprised of member selected from the group consisting of amphiphiles, dimyristylphosphatidylchlorine, dimyristylphosphatidylserine, polymers, metal hydrides, antibodies, and oligonucleotides.

20. The method of claim 15, wherein the step of depositing an active layer is performed with a printhead.

21. The method of claim 15, wherein the electromechanical device is a resonator.

22. The method of claim 21, wherein the resonator is comprised of a member selected from the group consisting of silicon, aluminum-nitride, silicon-carbide, gallium-nitride, and quartz.

23. The method of claim 15, wherein the electromechanical device is a MEMS device.

24. An apparatus for tuning a electromechanical 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 electromechanical device; and

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

25. The apparatus of claim 24, wherein the power means comprises a circuit card.

26. The apparatus of claim 24, wherein the power means comprises a piezoelectric element.

27. The apparatus of claim 24, wherein the power means comprises a wafer probe card.

28. The apparatus of claim 24, further comprising a shuttle and wafer bonder for packaging the electromechanical device in situ.

29. The apparatus of claim 24, wherein the electromechanical device is a resonator.

30. The apparatus of claim 29, further comprising an active layer deposited on the resonator for detecting chemical and biological agents.

31. The apparatus of claim 29, wherein the resonator is comprised of a member selected from the group of silicon, aluminum-nitride, silicon-carbide, gallium-nitride, quartz.

32. The apparatus of claim 24, wherein the electromechanical device is a MEMS device.