CN117013979B

CN117013979B - Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment

Info

Publication number: CN117013979B
Application number: CN202211609960.9A
Authority: CN
Inventors: 万晨庚
Original assignee: Beijing Xinxi Semiconductor Technology Co ltd
Current assignee: Beijing Xinxi Semiconductor Technology Co ltd
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2024-06-04
Anticipated expiration: 2042-12-14
Also published as: CN117013979A

Abstract

The embodiment of the disclosure provides a bulk acoustic wave resonator, a preparation method thereof, a filter and electronic equipment. The bulk acoustic wave resonator includes: a substrate; an acoustic mirror; a bottom electrode; a piezoelectric layer formed over the bottom electrode and covering the bottom electrode; and a top electrode formed over the piezoelectric layer; wherein the bulk acoustic wave resonator further comprises a frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure comprises a first frame structure formed inside the piezoelectric layer and a second frame structure formed above the piezoelectric layer, the first and second frame structures communicating with each other.

Description

Bulk acoustic wave resonator, preparation method thereof, filter and electronic equipment

Technical Field

The present invention relates to the field of electronic communications technologies, and in particular, to a bulk acoustic wave resonator, a method for manufacturing the bulk acoustic wave resonator, a filter, and an electronic device.

Background

The film bulk acoustic resonator filter (filmbulkacousticresonator, FBAR) is receiving increasing attention as one of the core devices of Radio Frequency (RF) front-end, mainly because of the high power, high bandwidth and excellent roll-off performance of the FBAR filter, and can well meet the current demands for Radio Frequency performance. Particularly, compared with a SAW (surfaceacousticwave ) filter, the FABR filter has great advantages in the aspect of high power, because the FBAR belongs to a longitudinal wave propagation mode of bulk acoustic waves, the excellent e33 performance of an AlN material can be utilized, and the energy of the acoustic waves is better converted.

However, for FBARs, the piezoelectric layer material and electrode material are not perfect single crystals with perfect Z-axis crystal orientation, and therefore there is some defect that causes the longitudinal wave propagation process to couple out the transverse wave. If this energy is not limited, it leaks out laterally, which in turn reduces the quality factor (Q) of the resonator.

In order to limit the lateral leakage of energy, the prior art generally sets a boundary structure near the top electrode, that is, an air ring structure and a frame structure, so as to limit the vibration of the edge of the resonator and increase the reflection of the lateral sound wave, thereby improving the Q value. Existing air ring structures and frame structures are typically disposed between the piezoelectric layer (i.e., the PZ layer) and the top electrode or in the PZ. However, these arrangements, while also reducing the leakage of lateral energy, can only limit the leakage of energy within one film layer. Further, whether the air ring structure and the frame structure are provided between the PZ layer and the top electrode or inside the PZ layer, only the transverse energy wave at the top electrode or only the transverse energy in the PZ layer can be limited, however, according to the above analysis, leakage of the transverse energy exists in each structure of the FBAR.

Accordingly, it is desirable to have a XXBDT2022011A-TD2206 that is more efficient at leaking lateral energy in various structures of an FBAR

Limited resonator, filter and electronic device.

Disclosure of Invention

In view of the above, embodiments of the present disclosure provide a bulk acoustic wave resonator and a method for manufacturing the same, which at least partially solve the problems in the prior art.

In a first aspect, embodiments of the present disclosure provide a bulk acoustic wave resonator, including:

A substrate 10, wherein an acoustic mirror 19 is formed on one side of the substrate 10;

A bottom electrode 12 formed above the acoustic mirror 19 and covering the acoustic mirror 19, wherein a face of the bottom electrode 12 facing the acoustic mirror 19 is horizontal, and a seed layer is formed below the bottom electrode 12;

a piezoelectric layer 13 formed above the bottom electrode 12 and covering the bottom electrode 12; and

A top electrode 16 formed above the piezoelectric layer 13; wherein the method comprises the steps of

The bulk acoustic wave resonator further includes a frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside the piezoelectric layer 13 and a second frame structure formed above the piezoelectric layer 13, the first frame structure and the second frame structure being in communication with each other.

According to an implementation form of the first aspect of the disclosure, the bulk acoustic wave resonator further comprises: the air ring structure 14 is formed at the edge of the bulk acoustic wave resonator, the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure.

According to an implementation form of the first aspect of the present disclosure, the outer boundary of the first frame structure is inside the inner boundary of the air ring structure 14; and the inner boundary of the first frame structure is flush with, outside of, or inside of the inner boundary of the second frame structure.

According to an implementation of the first aspect of the present disclosure, the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14; and the inner boundary of the first frame structure is flush with, outside of, or inside of the inner boundary of the second frame structure.

According to an implementation form of the first aspect of the present disclosure, the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14; and the inner boundary of the first frame structure and the second frame XXBDT2022011a-TD2206

The inner boundary of the structure is flush, outside the inner boundary of the second frame structure, or inside the inner boundary of the second frame structure.

According to one implementation of the first aspect of the present disclosure, the air ring structure 14 comprises a first air ring structure and a second air ring structure, wherein the first air ring structure is configured to be inside the piezoelectric layer 13 and in contact with the first frame structure, and the second air ring structure is configured to be above the piezoelectric layer 13 and in contact with the second frame structure, and the first air ring structure and the second air ring structure are in communication with each other.

According to an implementation form of the first aspect of the present disclosure, the outer boundary of the first air ring structure is outside the boundary of the acoustic mirror 19.

According to some implementations of the first aspect of the present disclosure, the top electrode 16 includes an associated raised structure 18.

According to some implementations of the first aspect of the present disclosure, the bulk acoustic wave resonator further includes a protective layer 17 formed at a topmost portion of the bulk acoustic wave resonator.

In a second aspect, embodiments of the present disclosure provide a method of manufacturing a bulk acoustic wave resonator, comprising:

An acoustic mirror 19 is formed on one side of the substrate 10;

Forming a bottom electrode 12 covering the acoustic mirror 19 above the acoustic mirror 19, wherein a face of the bottom electrode 12 facing the acoustic mirror 19 is set horizontal, and forming a seed layer below the bottom electrode 12;

forming a piezoelectric layer 13 covering the bottom electrode 12 above the bottom electrode 12; and

A top electrode 16 is formed over the piezoelectric layer 13, wherein

The method further includes forming a frame structure at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside the piezoelectric layer 13 and a second frame structure formed above the piezoelectric layer 13, the first and second frame structures being in communication with each other.

According to an implementation manner of the second aspect of the present disclosure, the method further includes: an air ring structure 14 is formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched with each other at the non-connecting side of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched with each other at the connecting side of the bulk acoustic wave resonator to form a bridge structure.

According to an implementation manner of the second aspect of the present disclosure, the outer boundary of the first frame structure is disposed inside the inner boundary of the air ring structure 14; and setting the inner boundary of the first frame structure to be substantially equal to XXBDT2022011A-TD2206

The inner boundary of the second frame structure is flush, is arranged outside the inner boundary of the second frame structure or is arranged inside the inner boundary of the second frame structure.

According to an implementation of the second aspect of the present disclosure, the outer boundary of the first frame structure is arranged flush with the inner boundary of the air ring structure 14; and disposing the inner boundary of the first frame structure flush with, outside of, or within the inner boundary of the second frame structure.

According to an implementation manner of the second aspect of the present disclosure, the outer boundary of the first frame structure is disposed outside the inner boundary of the air ring structure 14; and disposing the inner boundary of the first frame structure flush with, outside of, or within the inner boundary of the second frame structure.

According to one implementation of the second aspect of the present disclosure, the air ring structure 14 comprises a first air ring structure and a second air ring structure, wherein the first air ring structure is configured to be inside the piezoelectric layer 13 and in contact with the first frame structure, and the second air ring structure is configured to be above the piezoelectric layer 13 and in contact with the second frame structure, and the first air ring structure and the second air ring structure are in communication with each other.

According to an implementation manner of the second aspect of the present disclosure, the outer boundary of the first air ring structure is disposed outside the boundary of the acoustic mirror 19.

According to some implementations of the second aspect of the present disclosure, the method further comprises: an associated raised structure 18 is formed on the top electrode 16.

According to some implementations of the second aspect of the present disclosure, the method further comprises: a protective layer 17 is formed on top of the bulk acoustic wave resonator.

In a third aspect, embodiments of the present disclosure provide a filter comprising a bulk acoustic wave resonator according to the first aspect of embodiments of the present disclosure or any specific implementation thereof.

In a fourth aspect, embodiments of the present disclosure provide an electronic device comprising a bulk acoustic wave resonator according to the first aspect of the embodiments of the present disclosure or any specific implementation thereof, or comprising a filter according to the third aspect of the embodiments of the present disclosure.

According to the bulk acoustic wave resonator, the filter and the electronic equipment, the quality factors (Q values) of the resonator, the filter and the electronic equipment are effectively improved by arranging the frame structure which is communicated across the piezoelectric layer in the piezoelectric layer and above the piezoelectric layer and further arranging the double-layer air ring structure which is communicated across the piezoelectric layer in the piezoelectric layer and on the piezoelectric layer.

XXBDT2022011A-TD2206

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1-1 is a structural overhead view of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure;

FIGS. 1-2 are block diagrams of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure;

FIGS. 1-3 are graphs comparing the performance of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure with the prior art;

FIGS. 1-4 are graphs comparing the performance of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure with the prior art;

FIGS. 1-5 are graphs comparing the performance of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure with the prior art;

FIG. 2 is a block diagram of a second embodiment of a bulk acoustic wave resonator provided by the present disclosure;

FIG. 3 is a block diagram of a third embodiment of a bulk acoustic wave resonator provided by the present disclosure;

FIG. 4 is a block diagram of a fourth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

Fig. 5 is a block diagram of a fifth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 6 is a block diagram of a sixth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 7 is a block diagram of a seventh embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 8 is a block diagram of an eighth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 9 is a block diagram of a ninth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

Fig. 10 is a block diagram of a tenth embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 11 is a block diagram of an eleventh embodiment of a bulk acoustic wave resonator provided by the present disclosure;

fig. 12 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 13 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 14 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 15 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 16 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

Fig. 17 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 18 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure; XXBDT2022011A-TD2206

Fig. 19 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

Fig. 20 is a schematic diagram of a method of making a bulk acoustic wave resonator according to a first embodiment of the present disclosure;

fig. 21 is a schematic diagram of a method of manufacturing a bulk acoustic wave resonator according to a first embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

Other advantages and effects of the present disclosure will become readily apparent to those skilled in the art from the following disclosure, which describes embodiments of the present disclosure by way of specific examples. It will be apparent that the described embodiments are merely some, but not all embodiments of the present disclosure. The disclosure may be embodied or practiced in other different specific embodiments, and details within the subject specification may be modified or changed from various points of view and applications without departing from the spirit of the disclosure. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, based on the embodiments in this disclosure are intended to be within the scope of this disclosure.

It is noted that various aspects of the embodiments are described below within the scope of the following claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present disclosure, one skilled in the art will appreciate that one aspect described herein may be implemented independently of any other aspect, and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, such apparatus may be implemented and/or such methods practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should also be noted that the illustrations provided in the following embodiments merely illustrate the basic concepts of the disclosure by way of illustration, and only the components related to the disclosure are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided in order to provide a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

XXBDT2022011A-TD2206

Next, the structure of the bulk acoustic wave resonator of the embodiment of the present disclosure will be specifically described with reference to the drawings.

First, reference numerals in the embodiments of the present disclosure are described.

10: The substrate is made of monocrystalline silicon, gallium arsenide, sapphire, quartz, silicon carbide, SOI, etc.

12: The bottom electrode is made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

13: The piezoelectric layer is made of monocrystalline piezoelectric material, polycrystalline piezoelectric material or rare earth element doped material with a certain atomic ratio.

Specifically, the single crystal piezoelectric material is selected from single crystal aluminum nitride, single crystal gallium nitride, single crystal lithium niobate, single crystal lead zirconate titanate (PZT), single crystal potassium niobate, single crystal quartz thin film, or single crystal lithium tantalate; polycrystalline piezoelectric material (corresponding to single crystal, non-single crystal material), optionally polycrystalline aluminum nitride, zinc oxide, PZT, etc.; the rare earth element doped material containing the above-mentioned material in a certain atomic ratio may be, for example, doped aluminum nitride containing at least one rare earth element such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), or the like.

14: An air ring structure is an annular structure formed of air or other low acoustic resistance dielectric material (e.g., siO). Specifically, in the embodiments of the present disclosure, at the non-connecting side of the resonator, the air ring structure 14 and the frame structure cooperate to form a structure that is a cantilever structure, i.e., a wing structure; at the connecting edges, the air ring structure 14 and the frame structure are matched to form a bridge structure, namely a bridge structure. In certain embodiments according to the present disclosure, the air ring structure 14 includes a first air ring structure 14-1 and a second air ring structure 14-2.

15: And a non-connecting side frame structure at a portion of the non-connecting side of the bulk acoustic wave resonator. The material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals or an alloy thereof, etc. The wing structure is part of a non-connecting side frame structure.

16: The top electrode may be made of the same material as the bottom electrode 12, and may be made of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite of the above metals, or an alloy thereof. It should be understood that the top electrode 16 and bottom electrode 12 materials may also be different.

17: The material of the protective layer is not limited, and is preferably selected from aluminum nitride, silicon oxide, and the like, for trimming and protecting the top electrode 16.

18: The material of the upward protruding structure can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or the alloy thereof, and the like, so that the parasitic mode of the resonator can be limited, and the performance is improved.

19: An acoustic mirror, abbreviated as acoustic mirror, a reflecting structure composed of air. The lower surface of the acoustic mirror 19 as a resonator and the piezoelectric layers and electrodes constituting the resonator have large acoustic impedance differences, and can be XXBDT2022011A-TD2206

The acoustic wave inside the resonator is reflected, confining the acoustic wave energy in the acoustic mirror, forming a resonance. It should be understood that Bragg reflection layers and other equivalent forms may also be employed. Further, the acoustic mirror may be formed on the upper surface side of the substrate, or may be formed on the support layer side above the substrate, and is composed of the substrate, the support layer, and the bottom electrode. In the embodiments of the present disclosure, a cavity is used to form an acoustic mirror structure on the upper surface side of the substrate or on the support layer side above the substrate.

11. 20: The sacrificial material may be silicon oxide and its dopants.

21: And (3) connecting a side frame structure: the frame structure is at the portion of the connecting edge of the bulk acoustic wave resonator. The bridge structure 21 is part of a connecting side frame structure.

First embodiment

Next, with reference to fig. 1-1 to 1-5, the structure of a first embodiment of a bulk acoustic wave resonator provided by the present disclosure is described. It should be understood that fig. 1-2 show longitudinal cross-sectional views of the bulk acoustic wave resonator cut along the line AOA' in fig. 1-1.

As shown in fig. 1-2, the structure of the first embodiment of the bulk acoustic wave resonator provided in the present disclosure includes a substrate 10, a bottom electrode 12, a piezoelectric layer 13, an air ring structure 14, a non-connection side frame structure 15, a top electrode 16, a protective layer 17, an upward protruding structure 18, an acoustic mirror 19, and a connection side frame structure 21.

The substrate 10 may be a single layer or a composite film of any of single crystal silicon, gallium arsenide, sapphire, quartz, silicon carbide, SOI, etc.

On one side of the substrate 10, i.e. the upper side as shown in the figure, an acoustic mirror 19 is etched, the acoustic mirror 19 being capable of reflecting acoustic waves inside the resonator, confining the acoustic wave energy in the resonator, forming a resonance. Specifically, the lower surface of the acoustic mirror 19, which is a resonator, and the piezoelectric layers and electrodes constituting the resonator have large acoustic impedance differences, and can reflect sound waves inside the resonator, confine the sound wave energy in the resonator, and form resonance.

Furthermore, it is noted that although not shown, the support layer may be deposited over the substrate 10 first, and the acoustic mirror 19 may be formed by etching one side of the support layer. The material of the supporting layer can be selected from silicon nitride, silicon oxide, polysilicon and its adulterants, and organic matters.

A bottom electrode 12 covering the acoustic mirror 19 is deposited over the acoustic mirror 19. The lower surface of the bottom electrode 12, i.e. the surface facing the electrode ring 11 and the acoustic mirror 19, is horizontal. Furthermore, although not shown in the drawings, a seed layer may be deposited above the acoustic mirror 19 and below the bottom electrode 12.

A piezoelectric layer 13 is deposited over the bottom electrode 12, i.e. on the face of the bottom electrode 12 remote from said acoustic mirror 19. Piezoelectric layer 13 may be selected from single crystal piezoelectric material, polycrystalline piezoelectric material, or XXBDT2022011A-TD2206 containing the same

Rare earth element doped material with a certain atomic ratio.

A frame structure is deposited to span the piezoelectric layer 13 at the edge of the bulk acoustic wave resonator, inside the piezoelectric layer 13 and above the piezoelectric layer 13, the frame structure being a non-connecting side frame structure 15 at the non-connecting side of the bulk acoustic wave resonator and a connecting side frame structure 21 at the connecting side of the bulk acoustic wave resonator. The frame structure material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite or alloy of the above metals. The frame structure includes a first frame structure deposited within the piezoelectric layer 13 and a second frame structure deposited over the piezoelectric layer 13. The first frame structure is buried in the piezoelectric layer 13 to a depth h greater than 0 and communicates with the second frame structure. In addition, the first frame structure and the second frame structure may have the same thickness as the layers, or may have different thicknesses as the layers.

The frame structure is formed such that the thickness of one or more sides of the bulk acoustic wave resonator is greater than the thickness of the central region of the resonator, that is, the edge of the bulk acoustic wave resonator has one or more raised structures when viewed in cross-section.

Further, it is understood that the non-connection side frame structure 15 of the non-connection side of the bulk acoustic wave resonator includes a first frame structure and a second frame structure, and the connection side frame structure 21 of the connection side of the bulk acoustic wave resonator includes a first frame structure and a second frame structure.

Further, an air ring structure 14 is formed above the piezoelectric layer at the edge of the bulk acoustic wave resonator. As described above, it is a ring-like structure formed of air or other low acoustic resistance dielectric material (e.g., siO). More specifically, the air ring structure 14 and the frame structure (specifically, the non-connecting side frame structure 15) are fitted at the non-connecting side to form a wing structure, and the frame structure (specifically, the connecting side frame structure 21) and the frame structure form a bridge frame structure at the connecting side. That is, in the present embodiment, the structure arrangement of the non-connection side and the connection side is different, both the left and right sides of the connection side of the air ring structure 14 are surrounded by the connection side frame structure 21 to form a bridge structure, and only one side of the non-connection side of the air ring structure 14 is surrounded, in the present embodiment, one side of the non-connection side of the air ring structure 14 near the center of the bulk acoustic wave resonator is surrounded by the non-connection side frame structure 15 to form a wing structure. In other words, the air ring structure 14 is partially surrounded by the non-connecting side frame structure 15 and is entirely surrounded by the connecting side frame structure 21.

The width of the frame structure inwardly of the inner boundary of the air ring structure 14 is the effective width of the frame structure. As shown in fig. 1-2, d1 and d3 are the effective widths of the second frame structure of the non-connecting side and the second frame structure of the connecting side, respectively, and d2 and d4 are the effective widths of the first frame structure of the non-connecting side and the first frame structure of the connecting side. The values of d1, d2, d3 and d4 may be the same or different, and the width ranges from 0.1um to 10um. d1+d2 constitutes the effective width of the frame structure at the non-connecting side, i.e. the effective width of the non-connecting side frame structure 15, while d3+d4 constitutes the effective width of the frame structure at the connecting side, i.e. the effective XXBDT2022011A-TD2206 of the connecting side frame structure 21

Width of the material.

In the presently disclosed embodiments, the term "connecting side" refers to the side of the resonator that is connected to the other resonator or test electrode, typically by the bottom electrode 12 or top electrode 16, so that the top electrode of this side is not etched (as shown on the right side of FIGS. 1-2, its top electrode 16 is not etched); the term "non-connecting side" means that the top electrode 16 of the resonator on this side is etched away without being connected to other resonators or pads (as shown on the left side of fig. 1-2, the top electrode 16 is etched). That is, in fig. 1-2, the left side is the non-connecting side and the right side is the connecting side. In the upper and lower Wen Zhong of the present disclosure, "in" refers to a direction toward the center of the bulk acoustic wave resonator in the horizontal direction. "outside" refers to a direction toward the edge of the bulk acoustic wave resonator in the horizontal direction.

Further, as shown in fig. 1-2, a top electrode 16 and an associated raised structure 18 are also provided, the top electrode 16 may be the same material as the bottom electrode 12 or different, and the raised structure 18 is a raised structure on the top electrode 16 and may be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite of the above metals, or alloys thereof, and the like.

It is to be understood that the raised structures 18 are not required and that the omission of the raised structures 18 does not affect the implementation of the embodiments provided herein.

In addition, in order to protect the bulk acoustic wave resonator, a protective layer 17 is also formed on the topmost portion of the bulk acoustic wave resonator, and the structure of the protective layer 17 is not limited.

It is to be understood that the protective layer 17 is not required and that the omission of the protective layer 17 does not affect the implementation of the embodiments provided by the present invention.

In other words, in the first embodiment of the present disclosure, a bulk acoustic wave resonator includes:

A piezoelectric layer 13 formed above the bottom electrode 12 and covering the bottom electrode 12; and a top electrode 16 formed above the piezoelectric layer 13; wherein the bulk acoustic wave resonator further comprises

A frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside the piezoelectric layer 13 and a second frame structure formed above the piezoelectric layer 13, the first and second frame structures communicating with each other;

XXBDT2022011A-TD2206

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is within the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is level with the inner boundary of the second frame structure;

a top electrode 16 formed over the piezoelectric layer 13 and the air ring structure 14, wherein the top electrode 16 includes an upwardly convex structure 18; and

And a protective layer 17 formed over the top electrode 16 and covering the top electrode 16.

The bulk acoustic wave resonator according to the first embodiment of the present disclosure effectively improves the quality factors (Q values) of the resonator, the filter, and the electronic device by providing a frame structure in and above the piezoelectric layer that communicates across the piezoelectric layer, and further providing an air ring structure above the piezoelectric layer.

Specifically, as shown in fig. 1 to 3, in the case where the effective lengths of the frame structures are all 6um, and the conditions are the same except for the arrangement positions of the frame structures, the maximum value of the impedance Rp of the parallel resonance point is raised from 5059 Ω to 5489 Ω by arranging the frame structures communicating across the piezoelectric layer in and above the piezoelectric layer, which is improved by about 6%, compared with the conventional structure in which the frame structures are arranged on the piezoelectric layer.

In addition to improving the performance of Rp, the provision of a frame structure in and over the piezoelectric layer that communicates across the piezoelectric layer also has an impact on the Q value. Figures 1-4 show a graph of Q performance versus a conventionally disposed frame structure and a frame structure disposed in and above a piezoelectric layer in communication across the piezoelectric layer. Fs for both structures was 2.452GHz. As can be seen from fig. 1 to 4, although the maximum Q values of the two structures are substantially the same, under the frame structure of the same width, the frame structure which is communicated across the piezoelectric layer is provided in and above the piezoelectric layer under the frame structure of the same width, and under the premise of not affecting the maximum Q value, the Q value of the frame structure of the same width is effectively improved. While Q values below Fs frequencies have a greater effect on the left side of the passband of the resonator, higher values are more advantageous for the performance of the resonator. That is, the arrangement of the frame structure communicating across the piezoelectric layer within and above the piezoelectric layer can effectively enhance the performance of the resonator. Further, fig. 1-5 illustrate a smith chart comparison between a conventionally disposed frame structure and a frame structure disposed within and above a piezoelectric layer in communication across the piezoelectric layer. As shown in fig. 1-5, the closer the curve in the graph is to the outside of the circle, the larger the Q value is, and as can be seen from the curves in the two structural boxes, the smaller the curve fluctuation below Fs and the closer to the circle when the frame structure is arranged in and above the piezoelectric layer and is communicated across the piezoelectric layer, which further illustrates that the Q value below Fs can be raised by arranging the frame structure in and above the piezoelectric layer and is communicated across the piezoelectric layer.

XXBDT2022011A-TD2206

Second embodiment

Next, a second embodiment of the present disclosure will be described with reference to fig. 2. As shown in fig. 2, the difference compared to the first embodiment shown in fig. 1-2 is that the inner boundary of the first frame structure is outside the inner boundary of the second frame structure.

In other words, in the second embodiment of the present disclosure, a bulk acoustic wave resonator includes:

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is inside the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is outside the inner boundary of the second frame structure;

Further, as shown in fig. 2, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 and d5 are the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 and d6 are the effective width of the second frame structure connecting the side frame structures 21.

It is to be noted that, although the inner boundary of the first frame structure is outside the inner boundary of the second frame structure in the bulk acoustic wave resonator according to the second embodiment of the present disclosure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

XXBDT2022011A-TD2206

In addition, in order to avoid obscuring the present invention, only the differences between the second embodiment and the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Third embodiment

Next, a third embodiment of the present disclosure will be described with reference to fig. 3. As shown in fig. 3, the difference compared to the first embodiment shown in fig. 1-2 is that the inner boundary of the first frame structure is inside the inner boundary of the second frame structure.

In other words, in the third embodiment of the present disclosure, a bulk acoustic wave resonator includes:

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is within the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is within the inner boundary of the second frame structure;

In addition, as shown in fig. 3, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 is the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 is the effective width of the second frame structure connecting the side frame structures 21.

Note that although in the bulk acoustic wave resonator according to the third embodiment of the present disclosure, the first frame XXBDT2022011a-TD2206

The inner boundary of the structure is within the inner boundary of the second frame structure, but the quality factors (Q values) of the resonator, the filter and the electronic device can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the third embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Fourth embodiment

Next, a fourth embodiment of the present disclosure will be described with reference to fig. 4. As shown in fig. 4, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14, which is flush with the inner boundary of the second frame structure.

A top electrode 16 formed above the piezoelectric layer 13; wherein the bulk acoustic wave resonator further comprises

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, the outer boundary of the first frame structure is level with the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is level with the inner boundary of the second frame structure;

Further, as shown in fig. 4, the effective width of the first frame structure and the effective width of the second frame structure of the non-connecting side frame structure 15 overlap, denoted by d 2; the effective width of the first frame structure XXBDT2022011a-TD2206 and the effective width of the second frame structure of the connecting side frame structure 21 overlap, denoted by d 4.

It is to be noted that, although the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14 in the bulk acoustic wave resonator according to the fourth embodiment of the present disclosure, the inner boundary of the first frame structure is flush with the inner boundary of the second frame structure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the fourth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Fifth embodiment

Next, a fifth embodiment of the present disclosure will be described with reference to fig. 5. As shown in fig. 5, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14, which is outside the inner boundary of the second frame structure.

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, the outer boundary of the first frame structure is level with the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is outside the inner boundary of the second frame structure;

XXBDT2022011A-TD2206

Further, as shown in fig. 5, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 is the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 is the effective width of the second frame structure connecting the side frame structures 21.

It is to be noted that, although the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14 in the bulk acoustic wave resonator according to the fifth embodiment of the present disclosure, the inner boundary of the first frame structure is outside the inner boundary of the second frame structure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the fifth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Sixth embodiment

Next, a sixth embodiment of the present disclosure will be described with reference to fig. 6. As shown in fig. 6, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14, which is inside the inner boundary of the second frame structure.

The air ring structure 14 is formed at the edge of the bulk acoustic wave resonator, the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure XXBDT2022011A-TD2206

Wherein the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14, the inner boundary of the first frame structure being inside the inner boundary of the second frame structure;

Further, as shown in fig. 6, the effective width of the first frame structure and the effective width of the second frame structure of the non-connecting side frame structure 15 overlap, denoted by d 2; the effective width of the first frame structure and the effective width of the second frame structure of the connecting side frame structure 21 overlap, denoted by d 4.

It is to be noted that, although the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14 in the bulk acoustic wave resonator according to the sixth embodiment of the present disclosure, the inner boundary of the first frame structure is within the inner boundary of the second frame structure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the sixth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Seventh embodiment

Next, a seventh embodiment of the present disclosure will be described with reference to fig. 7. As shown in fig. 7, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14, which is flush with the inner boundary of the second frame structure.

XXBDT2022011A-TD2206

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is beyond the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is level with the inner boundary of the second frame structure;

Further, as shown in fig. 7, the effective width of the first frame structure and the effective width of the second frame structure of the non-connecting side frame structure 15 overlap, denoted by d 2; the effective width of the first frame structure and the effective width of the second frame structure of the connecting side frame structure 21 overlap, denoted by d 4.

It is to be noted that, although the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14 in the bulk acoustic wave resonator according to the seventh embodiment of the present disclosure, the inner boundary of the first frame structure is flush with the inner boundary of the second frame structure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the seventh embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Eighth embodiment

Next, an eighth embodiment of the present disclosure will be described with reference to fig. 8. As shown in fig. 8, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is outside the inner boundary of the second frame structure.

A frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure comprises XXBDT2022011a-TD2206

Includes a first frame structure formed inside the piezoelectric layer 13 and a second frame structure formed above the piezoelectric layer 13, the first frame structure and the second frame structure communicating with each other;

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is outside the inner boundary of the second frame structure;

Further, as shown in fig. 8, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 is the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 is the effective width of the second frame structure connecting the side frame structures 21.

It is to be noted that, although the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14 and the inner boundary of the first frame structure is outside the inner boundary of the second frame structure in the bulk acoustic wave resonator according to the eighth embodiment of the present disclosure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the eighth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Ninth embodiment

Next, a ninth embodiment of the present disclosure will be described with reference to fig. 9. As shown in fig. 9, the difference compared to the first embodiment shown in fig. 1-2 is that the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is inside the inner boundary of the second frame structure.

XXBDT2022011A-TD2206

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure, and the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14, and the inner boundary of the first frame structure is inside the inner boundary of the second frame structure;

Further, as shown in fig. 9, the effective width of the first frame structure and the effective width of the second frame structure of the non-connecting side frame structure 15 overlap, denoted by d 2; the effective width of the first frame structure and the effective width of the second frame structure of the connecting side frame structure 21 overlap, denoted by d 4.

It is to be noted that, although the outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14 and the inner boundary of the first frame structure is inside the inner boundary of the second frame structure in the bulk acoustic wave resonator according to the ninth embodiment of the present disclosure, the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be effectively improved as well.

In addition, in order to avoid obscuring the present invention, only the differences of the ninth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

Tenth embodiment

Next, a tenth embodiment of the present disclosure will be described with reference to fig. 10. As shown in fig. 10, the difference compared to the first embodiment shown in fig. 1-2 is that the bulk acoustic wave resonator according to the tenth embodiment of the present disclosure does not include the air ring structure 14.

A bottom electrode 12 formed above the acoustic mirror 19 and covering the acoustic mirror 19, wherein XXBDT2022011A-TD2206

The face of the bottom electrode 12 facing the acoustic mirror 19 is horizontal, and a seed layer is formed below the bottom electrode 12;

A frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside the piezoelectric layer 13 and a second frame structure formed above the piezoelectric layer 13, the first and second frame structures communicating with each other, an inner boundary of the first frame structure being flush with an inner boundary of the second frame structure;

Further, as shown in fig. 10, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 is the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 is the effective width of the second frame structure connecting the side frame structures 21.

Note that, although the air ring structure 14 is not included in the bulk acoustic wave resonator according to the tenth embodiment of the present disclosure, it is also effective in improving the quality factor (Q value) of the resonator, the filter, and the electronic apparatus.

In addition, in order to avoid obscuring the present invention, only the differences of the tenth embodiment from the first embodiment will be described herein, and the description of the remaining identical structures will be omitted.

It is to be noted that, although not shown, the air ring structure 14 in the second to ninth embodiments of the present disclosure may be omitted as well to obtain new modifications without departing from the spirit of the inventive concept of the present disclosure. In order to avoid causing unnecessary ambiguity, detailed descriptions of these modifications are omitted here.

Eleventh embodiment

Next, an eleventh embodiment of the present disclosure will be described with reference to fig. 11. As shown in fig. 11, compared with the first embodiment shown in fig. 1-2, the difference is that the air ring structure 14 of the bulk acoustic wave resonator according to the eleventh embodiment of the present disclosure is constituted by two air ring structures of a first air ring structure 14-1 and a second air ring structure 14-2.

XXBDT2022011A-TD2206

An air ring structure 14 formed at the edge of the bulk acoustic wave resonator, the air ring structure 14 and the frame structure being fitted at the non-connection side of the bulk acoustic wave resonator to form a wing structure, the air ring structure 14 and the frame structure being fitted at the connection side of the bulk acoustic wave resonator to form a bridge structure, the air ring structure 14 comprising a first air ring structure and a second air ring structure, wherein the first air ring structure is formed inside the piezoelectric layer 13 and in contact with the first frame structure, the second air ring structure is formed above the piezoelectric layer 13 and in contact with the second frame structure, the first air ring structure and the second air ring structure are in communication with each other, and an outer boundary of the first air ring structure is outside a boundary of the acoustic mirror 19;

Further, as shown in fig. 11, d2 is the effective width of the first frame structure of the non-connecting side frame structure 15, and d1 is the effective width of the second frame structure of the non-connecting side frame structure 15; d4 is the effective width of the first frame structure connecting the side frame structures 21, and d3 is the effective width of the second frame structure connecting the side frame structures 21.

Note that in the bulk acoustic wave resonator according to the eleventh embodiment of the present disclosure, there is not only a frame structure across the piezoelectric layer but also an air ring structure across the piezoelectric layer, so that the quality factors (Q values) of the resonator, the filter, and the electronic apparatus can be more effectively improved.

In addition, in order to avoid obscuring the present invention, only the eleventh embodiment and the first XXBDT2022011A-TD2206 are described herein

The differences between the embodiments will be omitted.

It should be noted that, although not shown, the air ring structure 14 in the second to ninth embodiments of the present disclosure may be prepared to include two air ring structures of the air ring structure 14-1 embedded in the piezoelectric layer and the air ring structure 14-2 formed above the piezoelectric layer 13 as well to obtain new modifications without departing from the spirit of the inventive concept of the present disclosure. In order to avoid causing unnecessary ambiguity, detailed descriptions of these modifications are omitted here.

Further, it is noted that the above-described first to eleventh embodiments are merely illustrative of the improved portions of the present invention compared to the prior art, and this is not limiting of the present invention, and the resonator structures shown in the present invention may also be presented in conjunction with other resonator structures, for example, may be combined with different acoustic mirror structures, different bottom electrode structures, or the like.

Method embodiments of preparing a bulk acoustic wave resonator according to embodiments of the present disclosure

In view of the first embodiment being an exemplary embodiment of the inventive concept of the present disclosure, next, a process of fabricating a bulk acoustic wave resonator according to the first embodiment of the present disclosure will be described in detail with reference to fig. 12 to 21.

Step 1. As shown in FIG. 12, the structure of the acoustic mirror 19 is etched on the substrate 10, and the etching process may be dry etching or wet etching, and the dry etching may be sputtering and ion beam milling, plasma etching (PLASMAETCHING), high-pressure plasma etching, high-density plasma (HDP) etching, or Reactive Ion Etching (RIE). As mentioned above, although not shown, it is equally possible to now deposit a support layer on the substrate 10 and then etch on one side of the support layer to obtain the structure of the acoustic mirror 19.

Step 2: as shown in fig. 13, a layer of phosphosilicate glass PSG is deposited as a sacrificial material layer 20 on the above-described etched substrate 10, and the thickness of the sacrificial material layer 20 is greater than the depth of the structure of the acoustic mirror 19 (the reference numerals for the acoustic mirror 19 are omitted in fig. 13-20 for unnecessary blurring). The deposition may be, for example, chemical vapor deposition CVD.

Step 3: as shown in fig. 14, the structure shown in fig. 13 is subjected to Chemical Mechanical Polishing (CMP) to expose the upper surface of the substrate 10 covered by the sacrificial material layer 20 and to make the upper surface of the sacrificial material layer 20 flush with the upper surface of the substrate 10, at which time the acoustic mirror 19 is filled with the sacrificial material 20, so that the labeling of the acoustic mirror 19 is omitted.

Step 4: as shown in fig. 15, a seed layer (not shown) and bottom electrode 12 material are deposited and etched over the structure shown in fig. 14 to provide bottom electrode 12. Specifically, a metal layer may be deposited on the surfaces of the substrate 10 and the sacrificial material by a sputtering or evaporation process or the like, and the metal layer may be patterned by photolithography and etching processes to form the bottom electrode 12.

Step 5: as shown in FIG. 16, piezoelectric layer 13 is deposited over the structure shown in FIG. 15 and over piezoelectric layer XXBDT2022011A-TD2206

13, An air ring sacrificial layer 11 is deposited and patterned.

Step 6: as shown in fig. 17, grooves are etched in the upper surface of the piezoelectric layer 13.

Step 7: as shown in fig. 18, the frame structure is prepared by depositing a metal layer on the piezoelectric layer 13 and the air ring sacrificial layer 11 and patterning them. As shown in fig. 18, the frame structure is prepared as two parts of the non-connecting side frame structure 15 and the connecting side frame structure 21 by patterning. In this example of the step, the first frame structure in the piezoelectric layer and the second frame structure above the piezoelectric layer are prepared in the same layer and have the same thickness, but it is understood that the first frame structure and the second frame structure may be prepared in layers as well and the materials may be the same or different.

Step 9: as shown in fig. 19, a metal layer is deposited on the upper surface of the structure shown in fig. 18 and patterned and etched to form the top electrode 16 and the raised structure 18.

Step 10: as shown in fig. 20, a passivation layer material is disposed and patterned on the upper surface of the structure shown in fig. 19 to form a protective layer 17.

Step 11: as shown in fig. 21, the materials of the sacrificial layer 20 and the air ring sacrificial layer 11 are released, resulting in the air ring structure 14, the acoustic mirror 19 and the final bulk acoustic resonator.

A method of manufacturing a bulk acoustic wave resonator according to a first embodiment of the present disclosure is described above with reference to fig. 12 to 21. Although not described in detail, it is noted that the respective structural features, materials, and the like of the bulk acoustic wave resonator described above with reference to fig. 1-2 are also applicable to the manufacturing method.

Although the process of manufacturing the bulk acoustic wave resonator according to the first embodiment of the present disclosure is described above by way of illustration, it should be understood that the bulk acoustic wave resonators of the second to eleventh embodiments may be similarly manufactured.

For example, the method of manufacturing the bulk acoustic wave resonator in the second to ninth embodiments is similar to that in the first embodiment, except for patterning of the air ring, grooves in the piezoelectric layer, and patterning of the frame structure. The difference in these steps can be clearly understood from the structural differences in the second embodiment to the ninth embodiment, and thus a detailed description thereof is omitted herein to avoid unnecessarily obscuring the present invention.

For example, the method of manufacturing the bulk acoustic wave resonator in the tenth embodiment is similar to that in the first embodiment, except that the process of depositing the air ring sacrificial layer 11 and patterning in step 5 is omitted.

For example, the method of manufacturing the bulk acoustic wave resonator in the eleventh embodiment is similar to that in the first embodiment, except for steps 5 and 6. In the preparation of the bulk acoustic wave resonator in the eleventh embodiment, a groove is etched in the upper surface of the piezoelectric layer 13, and an air ring sacrificial layer 11 is deposited in the groove and over the piezoelectric layer and patterned. The differences in these steps can be clearly seen in the structural differences of the eleventh embodiment XXBDT2022011A-TD2206

As a solution, a detailed description thereof is omitted herein to avoid unnecessarily obscuring the present invention.

Furthermore, bulk acoustic wave resonators according to the present disclosure may be used to form filters or electronic devices, as will be appreciated by those skilled in the art. The electronic device includes, but is not limited to, intermediate products such as a radio frequency front end, a filtering and amplifying module, and terminal products such as a mobile phone, a WIFI, an unmanned aerial vehicle, and the like.

Further, the present disclosure may also have the following configuration:

(1) A bulk acoustic wave resonator, comprising:

A piezoelectric layer 13 formed above the bottom electrode 12 and covering the bottom electrode 12; and a top electrode 16 formed above the piezoelectric layer 13; wherein the method comprises the steps of

(2) The bulk acoustic wave resonator according to (1), characterized in that it further comprises: the air ring structure 14 is formed at the edge of the bulk acoustic wave resonator, the air ring structure 14 and the frame structure are matched at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched at the connecting edge of the bulk acoustic wave resonator to form a bridge structure.

(3) The bulk acoustic wave resonator according to (2), characterized in that,

The outer boundary of the first frame structure is inside the inner boundary of the air ring structure 14; and

The inner boundary of the first frame structure is flush with, outside of, or inside of the inner boundary of the second frame structure.

(4) The bulk acoustic wave resonator according to (2), characterized in that,

The outer boundary of the first frame structure is flush with the inner boundary of the air ring structure 14; and

The inner boundary of the first frame structure is flush with the inner boundary of the second frame structure at XXBDT2022011A-TD2206

Outside the inner boundary of the two frame structures or inside the inner boundary of the second frame structure.

(5) The bulk acoustic wave resonator according to (2), characterized in that,

The outer boundary of the first frame structure is outside the inner boundary of the air ring structure 14; and

(6) The bulk acoustic wave resonator according to any one of (2) to (5), characterized in that the air ring structure 14 comprises a first air ring structure and a second air ring structure, wherein the first air ring structure is formed inside the piezoelectric layer 13 and in contact with the first frame structure, and the second air ring structure is formed above the piezoelectric layer 13 and in contact with the second frame structure, the first air ring structure and the second air ring structure being in communication with each other.

(7) The bulk acoustic resonator according to (6), characterized in that the outer boundary of the first air ring structure is outside the boundary of the acoustic mirror 19.

(8) A method of making a bulk acoustic wave resonator comprising:

An acoustic mirror 19 is formed on one side of the substrate 10;

A top electrode 16 is formed over the piezoelectric layer 13, wherein

(9) The method of manufacturing a bulk acoustic wave resonator according to (8), characterized in that the method further comprises: an air ring structure 14 is formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure 14 and the frame structure are matched with each other at the non-connecting side of the bulk acoustic wave resonator to form a wing structure, and the air ring structure 14 and the frame structure are matched with each other at the connecting side of the bulk acoustic wave resonator to form a bridge structure. XXBDT2022011A-TD2206

(10) The method for producing a bulk acoustic wave resonator according to (9), characterized in that,

Disposing the outer boundary of the first frame structure inwardly of the inner boundary of the air ring structure 14; and

The inner boundary of the first frame structure is arranged to be flush with, outside or inside the inner boundary of the second frame structure.

(11) The method for producing a bulk acoustic wave resonator according to (9), characterized in that,

Setting the outer boundary of the first frame structure flush with the inner boundary of the air ring structure 14; and

(12) The method for producing a bulk acoustic wave resonator according to (9), characterized in that,

Disposing the outer boundary of the first frame structure outside the inner boundary of the air ring structure 14; and

(13) The method for producing a bulk acoustic wave resonator according to any one of (9) to (12), characterized in that,

The air ring structure 14 includes a first air ring structure formed inside the piezoelectric layer 13 and in contact with the first frame structure, and a second air ring structure formed above the piezoelectric layer 13 and in contact with the second frame structure, the first air ring structure and the second air ring structure being in communication with each other.

(14) The method of manufacturing a bulk acoustic wave resonator according to (13), characterized in that the outer boundary of the first air ring structure is arranged outside the boundary of the acoustic mirror 19.

(15) A filter comprising the bulk acoustic wave resonator according to any one of (1) to (7).

XXBDT2022011A-TD2206

(16) An electronic device comprising the bulk acoustic wave resonator according to any one of (1) to (7) or comprising the filter according to (15).

The foregoing is merely specific embodiments of the disclosure, but the protection scope of the disclosure is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the disclosure are intended to be covered by the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A bulk acoustic wave resonator, comprising:

a substrate (10), wherein an acoustic mirror (19) is formed on one side of the substrate (10);

a bottom electrode (12) formed above the acoustic mirror (19) and covering the acoustic mirror (19), wherein a face of the bottom electrode (12) facing the acoustic mirror (19) is horizontal, and a seed layer is formed below the bottom electrode (12);

A piezoelectric layer (13) formed above the bottom electrode (12) and covering the bottom electrode (12); and

A top electrode (16) formed above the piezoelectric layer (13); wherein the method comprises the steps of

The bulk acoustic wave resonator further includes a frame structure formed at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside an upper surface of the piezoelectric layer (13) and a second frame structure formed above the piezoelectric layer (13), the first and second frame structures communicating with each other;

The bulk acoustic wave resonator further includes: the air ring structure (14) is formed at the edge of the bulk acoustic wave resonator, the air ring structure (14) and the frame structure are matched with the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure (14) and the frame structure are matched with the connecting edge of the bulk acoustic wave resonator to form a bridge structure;

the outer boundary of the first frame structure is flush with the inner boundary of the air ring structure (14); and

2. The bulk acoustic wave resonator according to claim 1, characterized in that,

The outer boundary of the first frame structure is inside the inner boundary of the air ring structure (14); and

3. The bulk acoustic wave resonator according to claim 2, characterized in that,

The outer boundary of the first frame structure is outside the inner boundary of the air ring structure (14); and

4. A bulk acoustic wave resonator according to any of claims 2-3, characterized in that the air ring structure (14) comprises a first air ring structure and a second air ring structure, wherein the first air ring structure is formed inside the piezoelectric layer (13) and in contact with the first frame structure, and the second air ring structure is formed above the piezoelectric layer (13) and in contact with the second frame structure, the first air ring structure and the second air ring structure being in communication with each other.

5. Bulk acoustic resonator according to claim 4, characterized in that the outer boundary of the first air ring structure is outside the boundary of the acoustic mirror (19).

6. A method of making a bulk acoustic wave resonator comprising:

Forming an acoustic mirror (19) on one side of the substrate (10);

Forming a bottom electrode (12) covering the acoustic mirror (19) above the acoustic mirror (19), wherein a face of the bottom electrode (12) facing the acoustic mirror (19) is set horizontal, and forming a seed layer below the bottom electrode (12);

Forming a piezoelectric layer (13) covering the bottom electrode (12) above the bottom electrode (12); and

Forming a top electrode (16) over the piezoelectric layer (13), wherein

The method further includes forming a frame structure at an edge of the bulk acoustic wave resonator such that a thickness of the edge of the bulk acoustic wave resonator is greater than a thickness of a central region of the bulk acoustic wave resonator, wherein the frame structure includes a first frame structure formed inside an upper surface of the piezoelectric layer (13) and a second frame structure formed above the piezoelectric layer (13), the first and second frame structures communicating with each other;

the method further comprises the steps of: an air ring structure (14) is formed at the edge of the bulk acoustic wave resonator, wherein the air ring structure (14) and the frame structure are matched with each other at the non-connecting edge of the bulk acoustic wave resonator to form a wing structure, and the air ring structure (14) and the frame structure are matched with each other at the connecting edge of the bulk acoustic wave resonator to form a bridge structure;

-locating the outer boundary of the first frame structure inside the inner boundary of the air ring structure (14); and

7. The method of manufacturing a bulk acoustic wave resonator according to claim 6, characterized in that,

-Setting the outer boundary of the first frame structure flush with the inner boundary of the air ring structure (14); and

8. The method of manufacturing a bulk acoustic wave resonator according to claim 6, characterized in that,

-Arranging the outer boundary of the first frame structure outside the inner boundary of the air ring structure (14); and

9. A method for producing a bulk acoustic wave resonator according to any of claims 6 to 8,

The air ring structure (14) comprises a first air ring structure and a second air ring structure, wherein the first air ring structure is formed inside the piezoelectric layer (13) and is in contact with the first frame structure, the second air ring structure is formed above the piezoelectric layer (13) and is in contact with the second frame structure, and the first air ring structure and the second air ring structure are communicated with each other.

10. A method of manufacturing a bulk acoustic wave resonator according to claim 9, characterized in that the outer boundary of the first air ring structure is arranged outside the boundary of the acoustic mirror (19).

11. A filter comprising a bulk acoustic wave resonator according to any of claims 1-5.

12. An electronic device comprising a bulk acoustic wave resonator according to any of claims 1-5 or comprising a filter according to claim 11.