US-12627279-B2 - Radio frequency acoustic wave device with imbalanced raised frame

Abstract

A bulk acoustic wave resonator device comprises a piezoelectric material layer, a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer, a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer, and an oxide raised frame disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and surrounding a central active region of the bulk acoustic wave resonator device, the central active region having a first side and a second side, the oxide raised frame having a width on the first side of the central active region that is different from the width of the oxide raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator.

Inventors

• Jiansong LIU
• Kwang Jae Shin
• Jae Hyung Lee
• Jong Duk Han

Assignees

• SKYWORKS GLOBAL PTE. LTD.

Dates

Publication Date

20260512

Application Date

20220701

Claims (19)

1. 1 . A bulk acoustic wave resonator device comprising: a piezoelectric material layer having an upper surface and a lower surface; a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer and an upper surface; a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer and a lower surface; an oxide raised frame surrounding a central active region of the bulk acoustic wave resonator device, the oxide raised frame defined in an oxide raised frame region by a layer of dielectric material disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and a first portion of a third metal layer disposed on the upper surface of the first metal layer; a metal raised frame disposed on the upper surface of the first metal layer and surrounding the central active region, the metal raised frame defined in a metal raised frame region by a second portion of the third metal layer disposed on the upper surface of the first metal layer, no layer of dielectric material being disposed between the lower surface of the first metal layer and the upper surface of the piezoelectric material layer or between the upper surface of the second metal layer and the lower surface of the piezoelectric material layer in the metal raised frame region, the second portion of the third metal layer including a first region proximate the central active region in which an upper surface of the second portion of the third metal layer is upwardly tapered, a second region disposed on an opposite side of the first region from the central active region in which the upper surface of the second portion of the third metal layer is planar and parallel to the upper surface of the piezoelectric material layer, and a third region on an opposite side of the second region from the first region in which the upper surface of the second portion of the third metal layer is upwardly tapered, the central active region having a first side and a second side, the oxide raised frame having a width on the first side of the central active region that is different from the width of the oxide raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator; and a passivation layer disposed on an upper surface of the metal raised frame and on the upper surface of the first metal layer, a recessed frame region being defined by thinned portions of the passivation layer that define an outer boundary of the central active region.
2. 2 . The bulk acoustic wave resonator device of claim 1 further comprising: an interconnect electrically coupled to the first metal layer disposed on the first side of the central active region on an opposite side of the metal raised frame from the central active region; and an interconnect electrically coupled to the second metal layer disposed on the second side of the central active region on an opposite side of the metal raised frame from the central active region.
3. 3 . The bulk acoustic wave resonator device of claim 2 wherein the metal raised frame has a width on the first side of the central active region that is substantially the same as a width of the metal raised frame on the second side of the central active region.
4. 4 . The bulk acoustic wave resonator device of claim 2 wherein the width of the oxide raised frame on the second side of the central active region is greater than the width of the oxide raised frame on the first side of the central active region.
5. 5 . The bulk acoustic wave resonator device of claim 4 wherein the central active region includes at least one additional side, the width of the oxide raised frame on the at least one additional side of the central active region being substantially the same as the width of the oxide raised frame on the second side of the central active region.
6. 6 . The bulk acoustic wave resonator device of claim 2 wherein the width of the metal raised frame on the first side of the central active region is greater than the width of the oxide raised frame on the first side of the central active region.
7. 7 . The bulk acoustic wave resonator device of claim 2 wherein the width of the metal raised frame on the first side of the central active region is different from the width of the metal raised frame on the second side of the central active region.
8. 8 . The bulk acoustic wave resonator device of claim 7 wherein the width of the metal raised frame on the first side of the central active region is greater than the width of the metal raised frame on the second side of the central active region.
9. 9 . A bulk acoustic wave resonator device comprising: a piezoelectric material layer having an upper surface and a lower surface; a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer and an upper surface; a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer and a lower surface; an oxide raised frame surrounding a central active region of the bulk acoustic wave resonator device, the oxide raised frame defined in an oxide raised frame region by a layer of dielectric material disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and a first portion of a third metal layer disposed on the upper surface of the first metal layer; and a metal raised frame disposed on the upper surface of the first metal layer and surrounding the central active region of the bulk acoustic wave resonator device, the metal raised frame defined in a metal raised frame region by a second portion of the third metal layer disposed on the upper surface of the first metal layer, no layer of dielectric material being disposed between the lower surface of the first metal layer and the upper surface of the piezoelectric material layer or between the upper surface of the second metal layer and the lower surface of the piezoelectric material layer in the metal raised frame region, the second portion of the third metal layer including a first region proximate the central active region in which an upper surface of the second portion of the third metal layer is upwardly tapered, a second region disposed on an opposite side of the first region from the central active region in which the upper surface of the second portion of the third metal layer is planar and parallel to the upper surface of the piezoelectric material layer, and a third region on an opposite side of the second region from the first region in which the upper surface of the second portion of the third metal layer is upwardly tapered, the central active region having a first side and a second side, the metal raised frame having a width on the first side of the central active region that is different from a width of the metal raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator.
10. 10 . The bulk acoustic wave resonator device of claim 9 further comprising: an interconnect electrically coupled to the first metal layer disposed on the first side of the central active region on an opposite side of the metal raised frame from the central active region; and an interconnect electrically coupled to the second metal layer disposed on the second side of the central active region on an opposite side of the metal raised frame from the central active region.
11. 11 . The bulk acoustic wave resonator device of claim 9 wherein the width of the oxide raised frame on the first side of the central active region is greater than the width of the metal raised frame on the first side of the central active region.
12. 12 . The bulk acoustic wave resonator device of claim 9 wherein the width of the oxide raised frame on the first side of the central active region is different from the width of the oxide raised frame on the second side of the central active region.
13. 13 . The bulk acoustic wave resonator device of claim 12 wherein the width of the oxide raised frame on the second side of the central active region is greater than the width of the oxide raised frame on the first side of the central active region.
14. 14 . The bulk acoustic wave resonator device of claim 9 wherein the oxide raised frame has a width on the first side of the central active region that is substantially the same as a width of the oxide raised frame on the second side of the central active region.
15. 15 . The bulk acoustic wave resonator device of claim 9 wherein the width of the metal raised frame on the second side of the central active region is greater than the width of the metal raised frame on the first side of the central active region.
16. 16 . The bulk acoustic wave resonator device of claim 9 wherein the central active region includes at least one additional side, the width of the metal raised frame on the at least one additional side of the central active region being substantially the same as the width of the metal raised frame on the second side of the central active region.
17. 17 . A radio frequency filter including the bulk acoustic wave resonator device of claim 9 .
18. 18 . A radio frequency module including the radio frequency filter of claim 17 .
19. 19 . A radio frequency device including the radio frequency module of claim 18 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 63/217,830, titled “RADIO FREQUENCY ACOUSTIC WAVE DEVICE WITH IMBALANCED RAISED FRAME,” filed Jul. 2, 2021, the entire contents of which is incorporated herein by reference for all purposes. BACKGROUND Technical Field The present disclosure generally relates to bulk acoustic wave resonators. Description of the Related Art A bulk acoustic wave resonator is a device having a piezoelectric material disposed between two electrodes. When an electromagnetic signal is applied to one of the electrodes, an acoustic wave is generated in the piezoelectric material and propagates to the other electrode. Depending on the thickness of the piezoelectric material, resonance of such an acoustic wave is established, and on the other electrode, an electromagnetic signal having a frequency corresponding to the frequency of the resonant acoustic wave is generated. Thus, such a bulk acoustic resonator can be utilized to provide filtering functionality for an electromagnetic signal such as a radio-frequency (RF) signal. In many applications, the piezoelectric material between the electrodes is relatively thin and implemented as a film. Thus, a bulk acoustic resonator is sometimes referred to as a thin-film bulk acoustic resonator (TFBAR) or as a film bulk acoustic resonator (FBAR). SUMMARY In accordance with one aspect, there is provided a bulk acoustic wave resonator device. The bulk acoustic wave resonator device comprises a piezoelectric material layer having an upper surface and a lower surface, a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer and an upper surface, a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer and a lower surface, and an oxide raised frame disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and surrounding a central active region of the bulk acoustic wave resonator device, the central active region having a first side and a second side, the oxide raised frame having a width on the first side of the central active region that is different from the width of the oxide raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator. In some embodiments, the bulk acoustic wave resonator device further comprises a metal raised frame disposed on the upper surface of the first metal layer and surrounding the central active region. In some embodiments, the bulk acoustic wave resonator device further comprises an interconnect electrically coupled to the first metal layer disposed on the first side of the central active region on an opposite side of the metal raised frame from the central active region, and an interconnect electrically coupled to the second metal layer disposed on the second side of the central active region on an opposite side of the metal raised frame from the central active region. In some embodiments, the metal raised frame has a width on the first side of the central active region that is substantially the same as a width of the metal raised frame on the second side of the central active region. In some embodiments, the width of the oxide raised frame on the second side of the central active region is greater than the width of the oxide raised frame on the first side of the central active region. In some embodiments, the central active region includes at least one additional side, the width of the oxide raised frame on the at least one additional side of the central active region being substantially the same as the width of the oxide raised frame on the second side of the central active region. In some embodiments, the width of the metal raised frame on the first side of the central active region is greater than the width of the oxide raised frame on the first side of the central active region. In some embodiments, the width of the metal raised frame on the first side of the central active region is different from the width of the metal raised frame on the second side of the central active region. In some embodiments, the width of the metal raised frame on the first side of the central active region is greater than the width of the metal raised frame on the second side of the central active region. In accordance with another aspect, there is provided a bulk acoustic wave resonator device. The bulk acoustic wave resonator device comprises a piezoelectric material layer having an upper surface and a lower surface, a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer and an upper surface, a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer and a lower surface, and a metal raised frame disposed on the u