Support and decoupling structure for an acoustic resonator, acoustic resonator and corresponding integrated circuit

• US 20050023931A1
• Filed: 06/15/2004
• Published: 02/03/2005
• Est. Priority Date: 11/28/2002
• Status: Abandoned Application

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Bouche, Guillaume, Ancey, Pascal, Caruyer, Gregory
• Application Number:
  US10/868,383
• Publication Number:
  US 20050023931A1
• Time in Patent Office: Days
• US Class Current: 310/327
• CPC Class Codes: H03H 9/175 Acoustic mirrors

Abstract

An acoustic resonator assembly includes a layer of high-acoustic-impedance material and a layer of low-acoustic-impedance material made of a low-electrical-permittivity material. This assembly may support the resonator over an interconnect layer or act as a decoupling assembly between two active elements of the resonator. The assembly may alternatively include three low-acoustic impedance layers. Alternatively, the assembly may include three acoustic impedance layers wherein two of the layers are low acoustic impedance layers and the third layer has a higher acoustic impedance than the first two or alternatively is a high-acoustic impedance layer.

Claims

1. A decoupling structure, comprising:

at least one assembly positioned between first and second acoustic resonators, comprising;

a layer of high-acoustic-impedance material; and

a layer of low-acoustic-impedance material made of a low-electrical-permittivity material.

2. The structure according to claim 1, wherein the layer of low-acoustic-impedance material is placed between one of the two acoustic resonators and said layer of high-acoustic-impedance material.

3. The structure according to claim 1, wherein the layer of high-acoustic-impedance material is made of a same material as an electrode of one of the acoustic resonators.

4. The structure according to claim 1, wherein the low-acoustic-impedance material comprises SiOC.

5. The structure according to claim 1, wherein the low-acoustic-impedance material comprises at least 90% SiOC in weight.

6. The structure according to claim 1, wherein the low-acoustic-impedance material comprises porous SiOC.

7. The structure according to claim 1, wherein the layer of low-acoustic-impedance material comprises a plurality of sublayers comprising SiOC.

8. The structure according to claim 1, wherein the high-acoustic-impedance material comprises at least one material selected in the group consisting of:

aluminum, copper, nickel, gold, platinum, molybdenum.

9. An acoustic resonator, comprising:

at least two active elements; and

a decoupling assembly placed between pairs of active elements comprising at least a layer of low-acoustic-impedance material made of a low-electrical-permittivity material.

10. The resonator according to claim 9, wherein an active element comprises at least one piezoelectric layer placed between electrodes.

11. The resonator according to claim 9, wherein the decoupling assembly is placed between an upper electrode of a first active element and a lower electrode of a second active element.

12. The resonator according to claim 9, wherein the low-acoustic-impedance material comprises a SiOC material.

13. The resonator according to claim 9, wherein an electrode comprises at least one material elected in the group consisting of:

aluminum, copper, nickel, gold, platinum, molybdenum.

14. The resonator according to claim 9, wherein the decoupling assembly comprises no more than one layer of low-acoustic-impedance material.

15. The resonator according to claim 9, wherein the decoupling assembly comprises two layers of low-acoustic-impedance material.

16. The resonator according to claim 9, wherein the decoupling assembly comprises three layers of low-acoustic-impedance material.

17. An integrated circuit, comprising:

a substrate;

a set of interconnects; and

an acoustic resonator that is provided with at least two active elements and with a decoupling layer positioned between each pair of active elements.

18. The circuit according to claim 17, wherein the acoustic resonator is placed on the set of interconnects.

19. The circuit according to claim 17, wherein the acoustic resonator is placed near the set of interconnects.

20. The circuit according to claim 17, wherein a first acoustic resonator comprises a support on an interconnect layer, the support including at least one bilayer assembly comprising a layer of high-acoustic-impedance material and a layer of low-acoustic-impedance material made of a low-electrical-permittivity material.

21. The circuit according to claim 17, wherein the decoupling layer comprises at least a layer of low-acoustic-impedance material.

22. The circuit according to claim 17, wherein the low-acoustic-impedance material comprises a SiOC material.

23. The circuit according to claim 20, wherein the high-acoustic-impedance material comprises at least one material selected in the group consisting of:

aluminum nitride, copper, nickel, tungsten, gold, platinum, molybdenum.

24. A decoupling structure, comprising:

at least one assembly positioned between a first and second acoustic resonators, comprising;

a first layer of low-acoustic-impedance material having a first acoustic impedance; and

a second layer of low-acoustic-impedance material having a second acoustic impedance.

25. The structure according to claim 24, wherein the first layer of low-acoustic-impedance material comprises a layer of SiOC.

26. The structure according to claim 25, wherein the first layer of low-acoustic-impedance material comprises a layer at least 90% SiOC in weight.

27. The structure according to claim 25, wherein the second layer of low-acoustic-impedance material comprises a layer of porous SiOC.

28. A decoupling structure, comprising:

at least one assembly positioned between a first and second acoustic resonators, comprising;

a first and second layers of low-acoustic-impedance material having a first acoustic impedance;

a third layer of low-acoustic-impedance material having a second acoustic impedance.

29. The structure according to claim 28, wherein at least one of the layers of low-acoustic-impedance material comprises a layer of SiOC.

30. The structure according to claim 29, wherein the at least one layer of low-acoustic-impedance material comprises a layer at least 90% SiOC in weight.

31. The structure according to claim 29, wherein at least one other layer of low-acoustic-impedance material comprises a layer of porous SiOC.

32. The structure according to claim 28, wherein the third layer is a middle layer between the first and second layers.

33. The structure according to claim 32, wherein the second acoustic impedance is higher than the first acoustic impedance.

34. A decoupling structure, comprising:

at least one assembly positioned between a first and second acoustic resonators, comprising;

a first layer of low-acoustic-impedance material having a first acoustic impedance;

a second layer of low-acoustic-impedance material having a second acoustic impedance;

a layer of high-acoustic-impedance material.

35. The structure according to claim 34, wherein at least one of the first and second layers of low-acoustic-impedance material comprises a layer of SiOC.

36. The structure according to claim 35, wherein the at least one layer of low-acoustic-impedance material comprises a layer at least 90% SiOC in weight.

37. The structure according to claim 35, wherein the other of the first and second layers of low-acoustic-impedance material comprises a layer of porous SiOC.

38. The structure according to claim 34, wherein the third layer is a middle layer between the first and second layers.

39. The structure according to claim 34, wherein the second acoustic impedance is higher than the first acoustic impedance.

40. The structure according to claim 34, wherein the first and second acoustic impedances are the same.

41. An acoustic resonator, comprising:

a first, second and third active elements;

a support positioned under the first active element comprising a first high acoustic impedance layer and a first low acoustic impedance layer;

a first decoupling assembly positioned between the first and second active elements comprising plural layers of acoustic-impedance material; and

a second decoupling assembly positioned between the second and third active elements comprising plural layers of acoustic-impedance material.

42. The resonator of claim 41 wherein at least one of the first and second decoupling assemblies comprises:

a first layer of low-acoustic-impedance material having a first acoustic impedance; and

a second layer of low-acoustic-impedance material having a second acoustic impedance.

43. The resonator of claim 41 wherein at least one of the first and second decoupling assemblies comprises:

a first layer of low-acoustic-impedance material having a first acoustic impedance;

a second layer of low-acoustic-impedance material having a second acoustic impedance; and

a layer of high-acoustic-impedance material.