Stacked acoustic resonator comprising a bridge

• US 9,136,818 B2
• Filed: 03/29/2011
• Issued: 09/15/2015
• 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, Shirakawa, Alexandre, Bader, Stefan
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US13/074,262
• Publication Number:
  US 20120218055A1
• Time in Patent Office: 1,631 Days
• Field of Search: 333187-189, 310/312, 310321-324, 310334-335, 310/366
• US Class Current: 1/1
• CPC Class Codes: H03H 9/02 Details
• CPC Class Codes: H03H 9/02086 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/132 characterized by a particular shape
• CPC Class Codes: H03H 9/585 Stacked Crystal Filters [SCF]

Abstract

In accordance with a representative embodiment, a bulk acoustic wave (BAW) resonator structure, comprises: a first electrode disposed over a substrate; a first piezoelectric layer disposed over the first electrode; a second electrode disposed over the first piezoelectric layer; a second piezoelectric layer disposed over the second electrode; a third electrode disposed over the second piezoelectric layer; and a bridge disposed between the first electrode and the third electrode.

Claims

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

a substrate comprising a cavity;

a first electrode disposed over the substrate;

a planarization layer disposed over the substrate and adjacent to the first electrode, the planarization layer not overlapping the cavity;

a first piezoelectric layer disposed over the first electrode;

a second electrode disposed over the first piezoelectric layer;

a second piezoelectric layer disposed over the second electrode;

a third electrode disposed over the second piezoelectric layer; and

a bridge disposed between the first electrode and the third electrode, the bridge extending past an edge of the cavity or acoustic reflector.

2. A BAW resonator structure as claimed in claim 1, wherein the bridge is a first bridge, and the BAW resonator structure further comprises a second bridge disposed between the first electrode and the third electrode.

3. A BAW resonator structure as claimed in claim 2, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, and the first bridge is disposed along the first perimeter.

4. A BAW resonator structure as claimed in claim 3, the BAW resonator structure having a second perimeter bounding the active region of the BAW resonator structure, and a second bridge is disposed along the second perimeter.

5. A BAW resonator structure as claimed in claim 2, wherein the first bridge comprises a fill material having an acoustic impedance.

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 2, wherein the second bridge comprises a fill material having an acoustic impedance.

8. A BAW resonator structure as claimed in claim 7, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

9. A BAW resonator structure as claimed in claim 2, wherein neither the first bridge nor the second bridge is disposed in the first electrode.

10. A BAW resonator structure as claimed in claim 1, wherein the bridge comprises a fill material having an acoustic impedance.

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

12. A BAW resonator structure as claimed in claim 1, wherein the bridge comprises a first bridge disposed in the second electrode, and the BAW resonator structure further comprises a second bridge disposed in the third electrode.

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

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

15. A BAW resonator structure as claimed in claim 1, wherein the bridge comprises a first bridge disposed in the first piezoelectric layer, and the BAW resonator structure further comprises a second bridge disposed in the second piezoelectric layer.

16. A BAW resonator structure as claimed in claim 15, wherein the first bridge is disposed along a first perimeter of the BAW resonator structure.

17. A BAW resonator structure as claimed in claim 16, wherein the second bridge is disposed along a second perimeter of the BAW resonator structure.

18. A BAW resonator structure as claimed in claim 1, the planarization layer being a first planarization layer, and the BAW resonator structure further comprises a second planarization layer disposed over the first piezoelectric layer and adjacent to the second electrode, wherein the second planarization layer does not overlap the acoustic reflector.

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

a substrate comprising a cavity;

a first electrode disposed over the substrate;

a planarization layer disposed over the substrate and adjacent to the first electrode, the planarization layer not overlapping the cavity;

a first piezoelectric layer disposed over the first electrode;

a second electrode disposed over the first piezoelectric layer;

a second piezoelectric layer disposed over the second electrode;

a third electrode disposed over the second piezoelectric layer;

a bridge disposed between the first electrode and the third electrode, the bridge extending past an edge of the cavity or acoustic reflector; and

an inner raised region disposed over the third electrode.

20. A BAW resonator structure as claimed in claim 19, further comprising an outer raised region disposed over the third electrode.

21. A BAW resonator structure as claimed in claim 19, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, the bridge is disposed along the first perimeter, and the inner raised region is in the active region.

22. A BAW resonator structure as claimed in claim 19, the planarization layer being a first planarization layer, and the BAW resonator structure further comprises a second planarization layer disposed over the first piezoelectric layer and adjacent to the second electrode, wherein the second planarization layer does not overlap the acoustic reflector.

23. A BAW resonator structure as claimed in claim 19, wherein the bridge is a first bridge, and the BAW resonator structure further comprises a second bridge disposed between the first electrode and the third electrode.

24. A BAW resonator structure as claimed in claim 23, wherein the first bridge comprises a fill material having an acoustic impedance.

25. A BAW resonator structure as claimed in claim 23, wherein the second bridge comprises a fill material having an acoustic impedance.

26. A BAW resonator structure as claimed in claim 19, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, and the bridge is disposed along the first perimeter.

27. A BAW resonator structure as claimed in claim 26, wherein the BAW resonator structure has a second perimeter bounding the active region of the BAW resonator structure, and a second bridge is disposed along the second perimeter.

28. A BAW resonator structure as claimed in claim 19, wherein the bridge comprises a fill material having an acoustic impedance.

29. A BAW resonator structure as claimed in claim 19, wherein the bridge comprises a first bridge disposed in the second electrode, and the BAW resonator structure further comprises a second bridge disposed in the third electrode.

30. A BAW resonator structure as claimed in claim 29, wherein the first bridge is disposed along a first perimeter of the BAW resonator structure.

31. A BAW resonator structure as claimed in claim 30, wherein the second bridge is disposed along a second perimeter of the BAW resonator structure.

32. A BAW resonator as claimed in claim 19, wherein the bridge comprises a first bridge disposed in the first piezoelectric layer, and the BAW resonator structure further comprises a second bridge disposed in the second piezoelectric layer.

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

a substrate comprising an acoustic reflector;

a first electrode disposed over the substrate;

a planarization layer disposed over the substrate and adjacent to the first electrode, the planarization layer not overlapping the acoustic reflector;

a first piezoelectric layer disposed over the first electrode;

a second electrode disposed over the first piezoelectric layer;

a second piezoelectric layer disposed over the second electrode;

a third electrode disposed over the second piezoelectric layer; and

a bridge disposed between the first electrode and the third electrode, the bridge extending past an edge of the acoustic reflector.

34. A BAW resonator structure as claimed in claim 33, wherein the bridge is a first bridge, and the BAW resonator structure further comprises a second bridge disposed between the first electrode and the third electrode.

35. A BAW resonator structure as claimed in claim 34, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, and the first bridge is disposed along the first perimeter.

36. A BAW resonator structure as claimed in claim 35, the BAW resonator structure having a second perimeter bounding the active region of the BAW resonator structure, and the second bridge is disposed along the second perimeter.

37. A BAW resonator structure as claimed in claim 34, wherein the first bridge comprises a fill material having an acoustic impedance.

38. A BAW resonator structure as claimed in claim 37, wherein the first bridge is disposed along a first perimeter of the BAW resonator structure.

39. A BAW resonator structure as claimed in claim 37, wherein the fill material comprises non-etchable borosilicate glass (NEBSG).

40. A BAW resonator structure as claimed in claim 34, wherein the second bridge comprises a fill material having an acoustic impedance.

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

42. A BAW resonator structure as claimed in claim 33, wherein the bridge comprises a fill material having an acoustic impedance.

43. A BAW resonator structure as claimed in claim 42, wherein a second bridge is disposed along a second perimeter of the BAW resonator structure.

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

45. A BAW resonator structure as claimed in claim 33, wherein the bridge has a trapezoidal cross-sectional shape.

46. A BAW resonator structure as claimed in claim 45, wherein a second bridge is disposed along a second perimeter of the BAW resonator structure.

47. A BAW resonator structure as claimed in claim 33, wherein the bridge is a first bridge disposed in the second electrode, and the BAW resonator structure further comprises a second bridge disposed in the third electrode.

48. A BAW resonator structure as claimed in claim 33, wherein the bridge is a first bridge disposed in the first piezoelectric layer, and the BAW resonator structure further comprises a second bridge disposed in the second piezoelectric layer.

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

a substrate comprising an acoustic reflector;

a first electrode disposed over the substrate;

a planarization layer disposed over the substrate and adjacent to the first electrode, the planarization layer not overlapping the acoustic reflector;

a first piezoelectric layer disposed over the first electrode;

a second electrode disposed over the first piezoelectric layer;

a second piezoelectric layer disposed over the second electrode;

a third electrode disposed over the second piezoelectric layer;

a bridge disposed between the first electrode and the third electrode, the bridge extending past an edge of the acoustic reflector; and

an inner raised region disposed over the third electrode.

50. A BAW resonator structure as claimed in claim 49, further comprising an outer raised region disposed over the third electrode.

51. A BAW resonator structure as claimed in claim 49, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, the bridge is disposed along the first perimeter, and the inner raised region is in the active region.

52. A BAW resonator structure as claimed in claim 49, the planarization layer being a first planarization layer, and the BAW resonator structure further comprises a second planarization layer disposed over the first piezoelectric layer and adjacent to the second electrode, wherein the second planarization layer does not overlap the acoustic reflector.

53. A BAW resonator structure as claimed in claim 49, wherein the bridge is a first bridge, and the BAW resonator structure further comprises a second bridge disposed between the first electrode and the third electrode.

54. A BAW resonator structure as claimed in claim 53, wherein the first bridge comprises a fill material having an acoustic impedance.

55. A BAW resonator structure as claimed in claim 53, wherein the second bridge comprises a fill material having an acoustic impedance.

56. A BAW resonator structure as claimed in claim 49, wherein the BAW resonator structure has a first perimeter bounding an active region of the BAW resonator structure, and the bridge is disposed along the first perimeter.

57. A BAW resonator structure as claimed in claim 56, wherein the BAW resonator structure has a second perimeter bounding the active region of the BAW resonator structure, and a second bridge is disposed along the second perimeter.

58. A BAW resonator structure as claimed in claim 49, wherein the bridge comprises a fill material having an acoustic impedance.

59. A BAW resonator structure as claimed in claim 49, wherein the bridge comprises a first bridge disposed in the second electrode, and the BAW resonator structure further comprises a second bridge disposed in the third electrode.

60. A BAW resonator structure as claimed in claim 59, wherein the first bridge is disposed along a first perimeter of the BAW resonator structure.

61. A BAW resonator structure as claimed in claim 60, wherein the second bridge is disposed along a second perimeter of the BAW resonator structure.

62. A BAW resonator structure as claimed in claim 49, wherein the bridge comprises a first bridge disposed in the first piezoelectric layer, and the BAW resonator structure further comprises a second bridge disposed in the second piezoelectric layer.