Adjusting the frequency of film bulk acoustic resonators

• US 20040239450A1
• Filed: 05/30/2003
• Published: 12/02/2004
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Wang, Li-Peng, Ma, Qing, Rao, Valluri, Fortuna, Seth, Dibattista, Michael
• Granted Patent: US 6,975,184 B2
• Time in Patent Office: Days
• US Class Current: 333/188
• CPC Class Codes: H03H 2003/0428 of an electrode
• CPC Class Codes: H03H 2003/0435 of a piezoelectric layer
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient

Abstract

A material may be removed from the top electrode of a film bulk acoustic resonator to alter the mass loading effect and to adjust the frequency of one film bulk acoustic resonator on a wafer relative to other resonators on the same wafer. Similarly, the piezoelectric layer or the bottom electrode may be selectively milled with a focused ion beam to trim the resonator.

Claims

1. A method comprising:

forming a film bulk acoustic resonator on a wafer; and

selectively removing material from said resonator using a focused ion beam to adjust the frequency of the resonator.

2. The method of claim 1 including forming at least two film bulk acoustic resonators on the same wafer and applying a different level of beam power to each of said resonators.

3. The method of claim 1 including selectively removing material from a top electrode of said resonator to adjust the frequency of said resonator.

4. The method of claim 1 including selectively removing material from a piezoelectric layer of said resonator to adjust the frequency of said resonator.

5. The method of claim 1 including selectively removing material from a bottom electrode of said resonator to adjust the frequency of said resonator.

6. The method of claim 1 including selectively removing material from at least two of said top electrode, said bottom electrode, and said piezoelectric layer to adjust the frequency of said resonator.

7. The method of claim 1 including selectively removing material from a top and a bottom electrode of a resonator to adjust the frequency of said resonator.

8. The method of claim 1 including testing the resonator while selectively removing the material from said resonator using a focused ion beam.

9. The method of claim 1 including measuring the thickness of at least one of said bottom electrode, said top electrode, or said piezoelectric layer when forming a film bulk acoustic resonator.

10. The method of claim 9 including using the measured thickness to control the use of the focused ion beam to adjust the frequency of the resonator.

11. A method comprising:

forming a film bulk acoustic resonator having a top and bottom electrode and a piezoelectric layer between said electrodes; and

selectively removing material from at least one of said top electrode, bottom electrode, or piezoelectric film using a focused ion beam to adjust the frequency of said resonator.

12. The method of claim 11 including forming at least two film bulk acoustic resonators on the same wafer and applying a different level of beam power to each of said resonators.

13. The method of claim 11 including selectively removing material from the top electrode of said resonator to adjust the frequency of said resonator.

14. The method of claim 11 including selectively removing material from the piezoelectric layer of said resonator to adjust the frequency of said resonator.

15. The method of claim 11 including selectively removing material from the bottom electrode of said resonator to adjust the frequency of said resonator.

16. The method of claim 11 including selectively removing material from at least two of said top electrode, said bottom electrode, and said piezoelectric layer to adjust the frequency of said resonator.

17. The method of claim 11 including selectively removing material from the top and the bottom electrode of a resonator to adjust the frequency of said resonator.

18. The method of claim 11 including testing the resonator while selectively removing the material from said resonator using a focused ion beam.

19. The method of claim 11 including measuring the thickness of at least one of said bottom electrode, said top electrode, or said piezoelectric layer when forming a film bulk acoustic resonator.

20. The method of claim 19 including using the measured thickness to control the use of the focused ion beam to adjust the frequency of the resonator.

21. A method comprising:

forming a film bulk acoustic resonator having a top and bottom electrode layer and a piezoelectric layer between said electrodes; and

selectively removing material from at least two of said layers to adjust the frequency of said resonator.

22. The method of claim 21 including forming at least two film bulk acoustic resonators on the same wafer and applying a different level of beam power to each of said resonators.

23. The method of claim 21 including selectively removing material from the top electrode layer of said resonator to adjust the frequency of said resonator.

24. The method of claim 21 including selectively removing material from the piezoelectric layer of said resonator to adjust the frequency of said resonator.

25. The method of claim 21 including selectively removing material from the bottom electrode layer of said resonator to adjust the frequency of said resonator.

26. The method of claim 21 including selectively removing material from the top and the bottom electrode layers of a resonator to adjust the frequency of said resonator.

27. The method of claim 21 including testing the resonator while selectively removing the material from said resonator using a focused ion beam.

28. The method of claim 21 including measuring the thickness of at least one layer when forming a film bulk acoustic resonator.

29. The method of claim 28 including using the measured thickness to control the use of the focused ion beam to adjust the frequency of the resonator.