Coupled resonator filter comprising a bridge

• US 9,154,112 B2
• Filed: 02/28/2011
• Issued: 10/06/2015
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Burak, Dariusz
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US13/036,489
• Publication Number:
  US 20120218056A1
• Time in Patent Office: 1,681 Days
• Field of Search: 333187-189, 310322-324, 310/334, 310/335
• US Class Current: 1/1
• CPC Class Codes: H03H 9/02086 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/02118 of lateral leakage between adjacent resonators
• CPC Class Codes: H03H 9/132 characterized by a particular shape
• CPC Class Codes: H03H 9/58 Multiple crystal filters
• CPC Class Codes: H03H 9/584 Coupled Resonator Filters [CFR]

Abstract

In accordance with a representative embodiment, a bulk acoustic wave (BAW) resonator structure, comprises: a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode; a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode; an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator; and a bridge disposed between the first lower electrode of the first BAW resonator and the second upper electrode of the second BAW resonator.

Claims

1. A bulk acoustic wave (BAW) resonator structure, comprising:

a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode;

a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode;

an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator; and

a first bridge disposed between the first lower electrode of the first BAW resonator and the second upper electrode of the second BAW resonator, wherein the BAW resonator structure has a first perimeter, and the first bridge is disposed completely along the first perimeter; and

a second bridge disposed between the first upper electrode of the first BAW resonator and the second lower electrode of the second BAW resonator.

2. A BAW resonator structure as claimed in claim 1, wherein the first bridge has a trapezoidal cross-sectional shape.

3. A BAW resonator structure as claimed in claim 1, further comprising a fill material having acoustic impedance disposed beneath the first bridge.

4. A BAW resonator structure as claimed in claim 3, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

5. A BAW resonator structure as claimed in claim 1, further comprising a fill material having acoustic impedance disposed beneath the second bridge.

6. A BAW resonator structure as claimed in claim 5, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

7. A BAW resonator structure as claimed in claim 1, wherein the second bridge has a trapezoidal cross-sectional shape.

8. A BAW resonator structure as claimed in claim 1, wherein neither the first bridge nor the second bridge is disposed in the first lower electrode of the BAW resonator structure.

9. A BAW resonator structure as claimed in claim 1, wherein the first BAW resonator comprises a first bulk acoustic wave resonator (FBAR) and the second BAW resonator comprises a second FBAR.

10. A BAW resonator structure as claimed in claim 1, wherein the first BAW resonator comprises a first solidly mounted resonator (SMR) and the second BAW resonator comprises a second SMR.

11. A coupled resonator filter (CRF) comprising the BAW resonator structure of claim 1.

12. A bulk acoustic wave (BAW) resonator structure, comprising:

a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode;

a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode;

an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator;

a first bridge disposed in the first upper electrode of the first BAW resonator; and

a second bridge disposed in the second upper electrode, wherein the first bridge is disposed about a first perimeter of the BAW resonator structure.

13. A BAW resonator structure as claimed in claim 12, wherein the second bridge is disposed about a second perimeter of the BAW resonator structure.

14. A BAW resonator structure as claimed in claim 12, wherein the first bridge has a trapezoidal cross-sectional shape.

15. A BAW resonator structure as claimed in claim 12, wherein the second bridge has a trapezoidal cross-sectional shape.

16. A BAW resonator structure as claimed in claim 12, further comprising a fill material having acoustic impedance disposed beneath the first bridge.

17. A BAW resonator structure as claimed in claim 16, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

18. A BAW resonator structure as claimed in claim 12, further comprising a fill material having acoustic impedance disposed beneath the second bridge.

19. A BAW resonator structure as claimed in claim 18, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

20. A BAW resonator structure as claimed in claim 12, wherein neither the first bridge nor the second bridge is disposed in the first lower electrode of the BAW resonator structure.

21. A RAW resonator structure as claimed in claim 12, wherein the first RAW resonator comprises a first bulk acoustic wave resonator (FBAR) and the second BAW resonator comprises a second FBAR.

22. A BAW resonator structure as claimed in claim 21, further comprising a cavity disposed beneath the first and second FBARs, wherein the first bridge and the second bridge extend past an edge of the cavity.

23. A BAW resonator structure as claimed in claim 12, wherein the first BAW resonator comprises a first solidly mounted resonator (SMR) and the second BAW resonator comprises a second SMR.

24. A BAW resonator structure as claimed in claim 23, further comprising a Bragg reflector disposed beneath the first and second FBARs, wherein the first bridge and the second bridge extend past an edge of the Bragg reflector.

25. A coupled resonator filter (CRF) comprising the BAW resonator structure of claim 12.

26. A bulk acoustic wave (BAW) resonator structure, comprising:

a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode;

a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode;

an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator;

a first bridge disposed in the first piezoelectric layer; and

a second bridge disposed in the second piezoelectric layer, wherein the first bridge is disposed about a first perimeter of the BAW resonator structure.

27. A BAW resonator structure as claimed in claim 26, wherein the second bridge is disposed about a second perimeter of the BAW resonator structure.

28. A BAW resonator structure as claimed in claim 26, wherein the first bridge has a trapezoidal cross-sectional shape.

29. A BAW resonator structure as claimed in claim 26, wherein the second bridge has a trapezoidal cross-sectional shape.

30. A BAW resonator structure as claimed in claim 26, further comprising a fill material having acoustic impedance disposed beneath the first bridge.

31. A BAW resonator structure as claimed in claim 30, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

32. A BAW resonator structure as claimed in claim 26, further comprising a fill material having acoustic impedance disposed beneath the second bridge.

33. A BAW resonator structure as claimed in claim 32, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

34. A BAW resonator structure as claimed in claim 26, wherein neither the first bridge nor the second bridge is disposed in the first lower electrode of the BAW resonator structure.

35. A BAW resonator structure as claimed in claim 26, wherein the first BAW resonator comprises a first bulk acoustic wave resonator (FBAR) and the second BAW resonator comprises a second FBAR.

36. A BAW resonator structure as claimed in claim 35, further comprising a cavity disposed beneath the first and second FBARs, wherein the first bridge and the second bridge extend past an edge of the cavity.

37. A BAW resonator structure as claimed in claim 26, wherein the first BAW resonator comprises a first solidly mounted resonator (SMR) and the second BAW resonator comprises a second SMR.

38. A BAW resonator structure as claimed in claim 37, further comprising a Bragg reflector disposed beneath the first and second FBARs, wherein the first bridge and the second bridge extend past an edge of the Bragg reflector.

39. A coupled resonator filter (CRF) comprising the BAW resonator structure of claim 26.

40. A bulk acoustic wave (BAW) resonator structure, comprising:

a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode;

an acoustic reflector or a cavity disposed beneath the first BAW resonator

a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode;

an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator; and

a bridge disposed in the first piezoelectric layer, wherein the bridge is disposed about a perimeter of the BAW resonator structure, the bridge extending past an edge of the acoustic reflector or the cavity.

41. A BAW resonator structure as claimed in claim 40, wherein the bridge has a trapezoidal cross-sectional shape.

42. A BAW resonator structure as claimed in claim 40, further comprising a fill material having acoustic impedance disposed beneath the bridge.

43. A BAW resonator structure as claimed in claim 42, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

44. A BAW resonator structure as claimed in claim 40, wherein the first BAW resonator comprises a first bulk acoustic wave resonator (FBAR) and the second BAW resonator comprises a second FBAR.

45. A BAW resonator structure as claimed in claim 40, wherein the first BAW resonator comprises a first solidly mounted resonator (SMR) and the second BAW resonator comprises a second SMR.

46. A coupled resonator filter (CRF) comprising the BAW resonator structure of claim 40.