CN113659953B

CN113659953B - Bulk acoustic wave resonator assembly, manufacturing method and communication device

Info

Publication number: CN113659953B
Application number: CN202110926424.0A
Authority: CN
Inventors: 丁焱昆; 杨清华; 唐兆云; 赖志国
Original assignee: Suzhou Huntersun Electronics Co Ltd
Current assignee: Suzhou Huntersun Electronics Co Ltd
Priority date: 2021-08-12
Filing date: 2021-08-12
Publication date: 2023-10-27
Anticipated expiration: 2041-08-12
Also published as: CN113659953A

Abstract

The invention discloses a bulk acoustic wave resonator assembly, a preparation method and a communication device. The bulk acoustic wave resonator assembly includes: the substrate is provided with at least one sound reflecting structure on the surface or inside; at least one resonance unit located on a surface of the substrate, the resonance unit having a smaller dimension in a thickness direction perpendicular to the substrate than the resonance unit in a thickness direction parallel to the substrate; the projection of the resonant cells on the substrate is at least partially coincident with the projection of the acoustic reflection structure on the substrate, the acoustic reflection structure being configured to prevent transverse waves of the resonant cells from leaking to the substrate. According to the technical scheme provided by the embodiment of the invention, on the basis of improving the firmness of the device, the size of the bulk acoustic wave resonator assembly and the communication device in the direction vertical to the thickness direction of the substrate is reduced, and the transverse wave of the resonance unit is prevented from leaking to the substrate through the acoustic reflection structure.

Description

Bulk acoustic wave resonator assembly, manufacturing method and communication device

Technical Field

The embodiment of the invention relates to the technical field of semiconductors, in particular to a bulk acoustic wave resonator assembly, a preparation method and a communication device.

Background

With the continuous development of wireless communication technology, high-performance and small-sized communication devices are increasingly used.

The thin film bulk acoustic resonator (Film Bulk Acoustic Resonator), also called bulk acoustic resonator (Bulk AcousticWave), has the characteristics of small size, high operating frequency, low power consumption, high quality factor, compatibility with CMOS processes, and the like, and has become an important device in the field of radio frequency communication.

The prior bulk acoustic wave resonator assembly comprises a substrate and at least one resonance unit, wherein the resonance unit comprises a first electrode, a piezoelectric layer and a second electrode, and the first electrode, the piezoelectric layer and the second electrode are stacked on the surface of the substrate to form the resonance unit. When at least one resonance unit is arranged on the surface of the substrate, the size of the bulk acoustic wave resonator component and the size of the communication device formed by the bulk acoustic wave resonator component in the direction vertical to the thickness direction of the substrate are too large, which is not beneficial to forming the bulk acoustic wave resonator component and the communication device with miniaturization and high integration level, and the size of the acoustic reflection structure arranged on the surface of the substrate in the direction vertical to the thickness direction of the substrate is large, so that the firmness of the bulk acoustic wave resonator component is reduced.

Disclosure of Invention

In view of the above, embodiments of the present invention provide a bulk acoustic wave resonator assembly, a method for manufacturing the same, and a communication device, which are capable of reducing the dimensions of the bulk acoustic wave resonator assembly and the communication device in a direction perpendicular to the thickness of a substrate on the basis of improving the device firmness.

In a first aspect, an embodiment of the present invention provides a bulk acoustic wave resonator assembly, including:

a substrate, the surface or the inside of which is provided with at least one sound reflection structure;

at least one resonance unit located on the surface of the substrate, the dimension of the resonance unit in the thickness direction perpendicular to the substrate being smaller than the dimension of the resonance unit in the thickness direction parallel to the substrate, the vibration direction of the bulk acoustic wave of the resonance unit being perpendicular to the propagation direction of the bulk acoustic wave of the resonance unit;

the projection of the resonance unit on the substrate is at least partially overlapped with the projection of the sound reflection structure on the substrate, and the sound reflection structure is used for preventing transverse waves of the resonance unit from leaking to the substrate.

Optionally, the acoustic reflection structure includes any one of a cavity structure, a bragg reflection layer, and a backside via.

Optionally, the dimension of the acoustic reflecting structure is greater than or equal to 0.2 microns and less than or equal to 3 microns in a thickness direction perpendicular to the substrate.

Alternatively, the resonance unit includes a stacked structure of a first electrode, a piezoelectric layer, and a second electrode in a thickness direction perpendicular to the substrate.

Optionally, the number of the substrates is p, wherein in the thickness direction parallel to the substrates, the p substrates are parallel and are arranged at intervals, and the value of p comprises an integer greater than or equal to 1;

the first surface of the r-th substrate and/or the second surface opposite to the first surface is provided with Q _r A resonance unit, wherein the value of r comprises an integer greater than or equal to 1 and less than or equal to p, and Q is _r The values of (2) include integers greater than or equal to 1;

the bulk acoustic wave resonator assembly further comprises a conductive interconnection structure and a carrier plate, wherein the carrier plate is positioned on the first surface side of the p-th substrate, the conductive interconnection structure is used for leading out an electric signal of the resonance unit to the surface of the carrier plate, which is away from the p-th substrate, and/or the conductive interconnection structure is used for leading out the electric signal of the resonance unit to the second surface side of the 1-th substrate.

Optionally, the height of the resonance unit is smaller than the interval between the adjacent substrates, or the height of the resonance unit is smaller than the interval between the p-th substrate and the carrier plate.

Optionally, in the resonant units on the same surface of the r-th substrate, the k 1-th resonant unit and the k 2-th resonant unit are adjacently arranged, and the value of k1 is greater than or equal to 1 and less than Q _r The value of k2 is greater than or equal to 1 and less than Q _r Is an integer of (2);

the kth 1 resonance unit is arranged adjacent to the homonymous electrode of the kth 2 resonance unit; and/or the kth 1 resonant unit is arranged adjacent to the synonym electrode of the kth 2 resonant unit.

Optionally, the device further comprises a first horizontal connecting part and a second horizontal connecting part; the first horizontal connecting part is connected with the first electrode and forms an L shape with the first electrode; the second horizontal connecting part is connected with the second electrode and forms an L shape with the second electrode;

in the same resonant cell, the piezoelectric layer is located between the first electrode and the second electrode.

Optionally, in the resonant units on the same surface of the r-th substrate, when the k 1-th resonant unit is arranged adjacent to the electrode with the same name of the k 2-th resonant unit, the electrode with the same name of the k 1-th resonant unit and the electrode with the same name of the k 2-th resonant unit are connected into a U-shaped electrode, or the electrode with the same name of the k 1-th resonant unit and the electrode with the same name of the k 2-th resonant unit are electrically connected through the conductive interconnection structure.

Optionally, in the resonant units on the same surface of the r-th substrate, at least one resonant unit is spaced between the k 3-th resonant unit and the k 4-th resonant unit, where the value of k3 is greater than or equal to 1 and less than or equal to Q _r The value of k4 is greater than or equal to 1 and less than or equal to Q _r Is an integer of (2);

the kth 3 resonance unit and the kth 4 resonance unit homonymous electrode are electrically connected through the conductive interconnection structure;

or the kth 3 resonant unit and the kth 4 resonant unit are electrically connected through the conductive interconnection structure.

Optionally, in the resonant unit on the same surface of the r-th substrate, a suspended electrode of the m-th resonant unit is connected with the conductive interconnection structure;

the suspension electrode of the mth resonance unit comprises a first electrode, and the second electrode of the mth resonance unit is electrically connected with the homonymous electrode or the heteronymous electrode of the nth resonance unit;

or the suspension electrode of the mth resonance unit comprises a second electrode, the first electrode of the mth resonance unit is electrically connected with the homonymous electrode or the heteronymous electrode of the nth resonance unit, wherein the value of m is greater than or equal to 1 and less than or equal to Q _r The value of n is greater than or equal to 1 and less than or equal to Q _r And the values of m and n are different.

Optionally, the connection relation of the resonance units on the same surface of the r-th substrate comprises serial connection and/or parallel connection.

Optionally, the resonance units on the second surface of the t th substrate and the resonance units on the first surface of the t-1 th substrate are distributed in an interdigital mode, wherein the value of t comprises an integer greater than or equal to 2 and less than or equal to p.

Optionally, in a thickness direction perpendicular to the substrate, the resonant cells are spaced apart from each other by a first predetermined distance.

In a second aspect, an embodiment of the present invention provides a method for manufacturing a bulk acoustic wave resonator assembly, including:

providing a substrate, wherein at least one sound reflecting structure is arranged on the surface or inside the substrate;

forming at least one resonance unit on a surface of the substrate, the resonance unit having a smaller dimension in a thickness direction perpendicular to the substrate than the resonance unit in a thickness direction parallel to the substrate;

Optionally, forming at least one resonance unit on the surface of the substrate includes: forming at least one piezoelectric layer on the surface of the substrate; forming at least one first electrode on the surface of the substrate; at least one second electrode is formed on a surface of the substrate, wherein the resonance unit includes a stacked structure of the first electrode, the piezoelectric layer, and the second electrode in a thickness direction perpendicular to the substrate.

In a third aspect, an embodiment of the present invention provides a communication device, including a bulk acoustic wave resonator assembly as described in any of the first aspects;

the communication device includes at least one of a filter, a diplexer, and a multiplexer.

In the technical scheme provided by the embodiment, the dimension of at least one resonance unit in the thickness direction perpendicular to the substrate is smaller than the dimension of the resonance unit in the thickness direction parallel to the substrate, so that the dimension of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate is reduced, and the bulk acoustic wave resonator assembly which is miniaturized and high in integration level and a communication device formed by the bulk acoustic wave resonator assembly are formed. The gap between the resonance unit and the resonance unit can realize the effect of reflecting the longitudinal wave back to the resonance unit and preventing the leakage of the longitudinal wave. The projection of the sound reflection structure on the substrate is at least partially overlapped with the projection of the resonance unit on the substrate, and the sound reflection structure is used for preventing transverse waves in the resonance unit from leaking to the substrate, so that the loss of sound waves is reduced. And the size of the acoustic reflection structure needs to be matched with the resonance unit, and along with the reduction of the size of the bulk acoustic wave resonator component in the thickness direction perpendicular to the substrate, the size of the acoustic reflection structure in the thickness direction perpendicular to the substrate is in a smaller range, so that the firmness of the bulk acoustic wave resonator component is improved.

Drawings

FIG. 1 is a schematic diagram of a bulk acoustic wave resonator assembly of the prior art;

fig. 2 is a schematic structural diagram of a bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of yet another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of yet another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of yet another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 7 is a schematic top view of a bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 8 is a schematic view of a cross-sectional structure in the direction A1-A2 of the bulk acoustic wave resonator assembly shown in FIG. 7;

FIG. 9 is a topology of the bulk acoustic wave resonator assembly shown in FIG. 7;

FIG. 10 is a schematic top view of a bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view of the bulk acoustic wave resonator assembly of FIG. 10 in the B1-B2 direction;

FIG. 12 is a topology of the bulk acoustic wave resonator assembly shown in FIG. 10;

FIG. 13 is a schematic structural diagram of yet another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 14 is a topology of the bulk acoustic wave resonator assembly shown in FIG. 13;

FIG. 15 shows a flow diagram of a method of fabricating a bulk acoustic wave resonator assembly;

fig. 16 to fig. 20 are schematic cross-sectional structures corresponding to steps of a method for manufacturing a bulk acoustic wave resonator assembly according to an embodiment of the present invention;

FIG. 21 is a schematic flow chart included in step 120 in FIG. 15;

fig. 22 to 24 are schematic cross-sectional structures corresponding to the steps of the preparation method included in step 120.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

According to the technical scheme, the size of the bulk acoustic wave resonator component and the size of the communication device formed by the bulk acoustic wave resonator component in the direction perpendicular to the thickness direction of the substrate are too large, so that the bulk acoustic wave resonator component and the communication device which are miniaturized and high in integration level are not easy to form, and the size of the acoustic reflection structure arranged on the surface of the substrate in the direction perpendicular to the thickness direction of the substrate is large, so that the firmness of the bulk acoustic wave resonator component is reduced. For this reason, fig. 1 is a schematic structural diagram of a bulk acoustic wave resonator assembly in the prior art. Fig. 1 shows a cavity type bulk acoustic wave resonator assembly. The X direction is set perpendicular to the thickness direction of the substrate 10, and the Y direction is set parallel to the thickness direction of the substrate 10. Referring to fig. 1, the bulk acoustic wave resonator assembly includes a substrate 10 and at least one resonance unit 20, the surface of the substrate 10 is provided with a built-in cavity structure 101, and the resonance unit 20 includes a first electrode 21, a piezoelectric layer 22, and a second electrode 23. The dimension of the resonance unit 20 perpendicular to the thickness direction of the substrate 10 is larger than the dimension parallel to the thickness direction of the substrate 10, resulting in that the dimension of the bulk acoustic wave resonator assembly and the communication device formed of the bulk acoustic wave resonator assembly perpendicular to the thickness direction of the substrate 10 is too large when at least one resonance unit 20 is provided on the surface of the substrate 10, which is disadvantageous in forming a miniaturized and highly integrated bulk acoustic wave resonator assembly and communication device. The most basic structure of the bulk acoustic wave resonator is a sandwich structure formed by sandwiching the piezoelectric layer 22 between two electrodes, and the piezoelectric layer 22 is deformed under the action of the alternating electric fields of the first electrode 21 and the second electrode 23, and microscopically appears as phonon vibration, so that the acoustic wave vibrating in the piezoelectric layer 22 is macroscopically formed. The acoustic wave vibrates in the piezoelectric layer 22 to form a standing wave, primarily in the form of a longitudinal wave, but a small amount of a transverse wave is still present. In the longitudinal wave, the movement direction of the particles and the propagation direction of the acoustic wave are parallel, but each particle does not move in the direction of the acoustic wave, but vibrates back and forth in the respective equilibrium states. In transverse waves, the direction of movement of particles and the direction of propagation of sound waves are perpendicular to each other. The particles do not move in the propagation direction of the acoustic wave, but vibrate up and down in the respective equilibrium states. The longitudinal wave of the acoustic wave of the prior art resonance unit 20 mainly propagates in the thickness direction parallel to the substrate 10, and thus the acoustic reflection structure of the prior art is to prevent the longitudinal wave from leaking to the substrate 10. Illustratively, the acoustic reflecting structure in fig. 1 is a cavity structure 101. And the size of the bulk acoustic wave resonator assembly and the communication device formed by the bulk acoustic wave resonator assembly in the direction perpendicular to the thickness direction of the substrate 10 is relatively large, the cavity structure 101 is used as an acoustic reflection structure, the size of the cavity structure 101 needs to be matched with the resonance unit 20, the size of the cavity structure 101 in the direction perpendicular to the thickness direction of the substrate 10 is relatively large, and the built-in cavity structure 101 arranged on the surface of the substrate 10 further reduces the firmness of the bulk acoustic wave resonator assembly.

Aiming at the technical problems, the embodiment of the invention provides the following technical scheme:

fig. 2 is a schematic structural diagram of a bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 3 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 4 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Referring to fig. 2-4, the bulk acoustic wave resonator assembly includes: a substrate 10, the surface or inside of the substrate 10 being provided with at least one sound reflecting structure 102; at least one resonance unit 20, the resonance unit 20 is located on the surface of the substrate 10, the dimension of the resonance unit 20 in the thickness direction perpendicular to the substrate 10 is smaller than the dimension of the resonance unit 20 in the thickness direction parallel to the substrate 10, the projection of the resonance unit 20 on the substrate 10 is at least partially overlapped with the projection of the acoustic reflection structure 102 on the substrate 10, and the acoustic reflection structure 102 is used for preventing transverse waves in the resonance unit 20 from leaking to the substrate 10.

Fig. 2-4 illustrate an exemplary solution in which the projection of the resonator element 20 onto the substrate 10 is completely coincident with the projection of the acoustic reflection structure 102 onto the substrate 10. The embodiment of the invention further comprises a technical scheme that the projection of the resonance unit 20 on the substrate 10 is overlapped with the projection part of the acoustic reflection structure 102 on the substrate 10.

In the embodiment of the present invention, the direction perpendicular to the thickness direction of the substrate 10 is set as the X direction, and the direction parallel to the thickness direction of the substrate 10 is set as the Y direction. The dimension of the resonance unit 20 in the thickness direction perpendicular to the substrate 10 is smaller than the dimension of the resonance unit 20 in the thickness direction parallel to the substrate 10, and longitudinal waves in the acoustic wave of the resonance unit 20 mainly propagate in the thickness direction perpendicular to the substrate 10. The transverse wave in the acoustic wave of the resonance unit 20 mainly propagates in the thickness direction parallel to the substrate 10. In the embodiment of the invention, the resonance unit 20 and the gap between the resonance units 20 can realize the effect of reflecting the longitudinal wave back to the resonance unit 20 and preventing the longitudinal wave from leaking. In the conventional bulk acoustic wave resonator assembly shown in fig. 1, the cavity structure 101 can achieve the effect of reflecting the longitudinal wave back to the resonance unit 20 and preventing the leakage of the longitudinal wave. It is known that the transverse wave of the resonant unit 20 leaks to the substrate 10, which also causes the loss of the acoustic wave of the resonant unit 20. In the embodiment of the present invention, at least one acoustic reflection structure 102 is disposed on the surface or inside the substrate 10, the projection of the resonant cells 20 on the substrate 10 is at least partially overlapped with the projection of the acoustic reflection structure 102 on the substrate 10, and the acoustic reflection structure 102 is used for preventing the transverse wave in the resonant cells 20 from leaking to the substrate 10.

Alternatively, the acoustic reflection structure 102 includes any one of a cavity structure 102a, a bragg reflection layer 102b, and a back surface through hole 102 c. The back surface through hole 102c may be a tapered through hole or an equal diameter through hole.

Illustratively, shown in fig. 2 is a cavity structure 102a as an acoustic reflection structure 102 for preventing acoustic waves, in particular transverse waves, in the resonant cells 20 from leaking to the substrate 10. Shown in fig. 4 is a back through hole 102c as a means for preventing leakage of acoustic waves, particularly transverse waves, in the resonance unit 20 to the substrate 10. Since the acoustic impedance of air is close to 0 and the acoustic impedance of the resonance unit 20 is large, the acoustic wave, especially the transverse wave, transmitted to the cavity structure 102a or the back through hole 102c is almost totally reflected back to the resonance unit 20, so that the energy of the acoustic wave, especially the transverse wave, leaking out of the resonance unit 20 is extremely small, thereby having the effect of preventing the acoustic wave, especially the transverse wave, of the resonance unit 20 from leaking to the substrate 10.

Shown in fig. 3 is a bragg reflection layer 102b as an acoustic reflection structure 102 for preventing acoustic waves, in particular transverse waves, in the resonant cells 20 from leaking to the substrate 10. The bragg reflection layer 102b is formed by alternately stacking high and low acoustic impedance layers to prevent transverse waves of the resonance unit 20 from leaking to the substrate 10, each acoustic impedance layer has a thickness greater than 1/4 wavelength, and the greater the acoustic impedance ratio of the high and low acoustic impedance layers, the better the bragg reflection layer 102b is for preventing sound waves of the resonance unit 20, particularly transverse waves, from leaking to the substrate 10.

Specifically, compared to the technical solution in which the bragg reflection layer 102b and the back via 102c are used as the acoustic reflection structure 102, the cavity structure 102a is used as a bulk acoustic wave resonator component of the acoustic reflection structure 102, and has the characteristics of higher quality factor, smaller loss and higher electromechanical coupling coefficient.

In the technical solution provided in this embodiment, the dimension of at least one resonant unit 20 in the thickness direction perpendicular to the substrate 10 is smaller than the dimension of the resonant unit 20 in the thickness direction parallel to the substrate 10, which reduces the dimension of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10, and is beneficial to forming a miniaturized and highly integrated bulk acoustic wave resonator assembly and a communication device formed by the bulk acoustic wave resonator assembly. The resonance unit 20 and the gap between the resonance unit 20 can achieve an effect of reflecting the longitudinal wave back to the resonance unit 20, preventing leakage of the longitudinal wave. The projection of the acoustic reflection structure 102 on the substrate 10 and the projection of the resonance unit 20 on the substrate 10 are at least partially overlapped, and the acoustic reflection structure 102 is used for preventing transverse waves in the resonance unit 20 from leaking to the substrate 10, so that the loss of sound waves is reduced. And the size of the acoustic reflection structure 102 needs to be matched with the resonance unit 20, along with the reduction of the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10, the size of the acoustic reflection structure 102 in the thickness direction perpendicular to the substrate 10 is in a smaller range, so that the firmness of the bulk acoustic wave resonator assembly is improved.

Alternatively, the size of the sound reflecting structure 102 is greater than or equal to 0.2 micrometers and less than or equal to 3 micrometers in a direction perpendicular to the thickness of the substrate 10.

Specifically, the size of the sound reflecting structure 102 is smaller than 0.2 μm in the thickness direction perpendicular to the substrate 10, and the effect of preventing the acoustic wave of the resonance unit 20, particularly the transverse wave, from leaking to the substrate 10 is weak. The dimensions of the cavity structure 102a and the backside via 102c in the direction perpendicular to the thickness direction of the substrate 10 are greater than 3 micrometers, resulting in excessive material removal from the substrate 10 and thus insufficient supporting strength of the substrate 10, and reduced soundness of the bulk acoustic wave resonator assembly. The size of the bragg reflection layer 102b in the direction perpendicular to the thickness direction of the substrate 10 is greater than 3 micrometers, and the bragg reflection layer 102b is too pressurized against the substrate 10, so that the substrate 10 is easily damaged, and the firmness of the bulk acoustic wave resonator assembly is reduced.

In the thickness direction perpendicular to the substrate 10, the size of the acoustic reflection structure 102 is greater than or equal to 0.2 micrometers and less than or equal to 3 micrometers, so that on one hand, the bulk acoustic wave resonator assembly can effectively prevent the transverse wave of the resonance unit 20 from leaking to the substrate 10, and on the other hand, the firmness of the bulk acoustic wave resonator assembly can meet preset requirements. Preferably, the size of the sound reflecting structure 102 may be any one of 1.1 micrometers, 1.2 micrometers, 1.3 micrometers, or 1.6 micrometers in a thickness direction perpendicular to the substrate 10.

By way of example, the bulk acoustic wave resonator assembly shown in fig. 5-14 is described with the cavity structure 102a as an example of the acoustic reflective structure 102.

The arrangement of the resonance unit 20 on the surface of the substrate 10 will be specifically described. Fig. 5 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Alternatively, on the basis of the above technical solution, referring to fig. 5, in a thickness direction perpendicular to the substrate 10, the resonance unit 20 includes a laminated structure of a first electrode 21, a piezoelectric layer 22, and a second electrode 23.

The working principle of the resonance unit 20 in this embodiment is as follows: under the alternating electric field of the first electrode 21 and the second electrode 23, the piezoelectric layer 22 deforms, microscopically exhibits phonon vibration, and macroscopically forms an acoustic wave vibrating in the piezoelectric layer 22. The resonance unit 20 and the gap between the resonance unit 20 can achieve an effect of reflecting the longitudinal wave in the acoustic wave back to the resonance unit 20, preventing the leakage of the longitudinal wave. The acoustic reflection structure 102 serves to prevent acoustic waves, in particular transverse waves, in the resonator element 20 from leaking to the substrate 10. Since the resonance units 20 are vertically arranged on the surface of the substrate 10, the area of the resonance units 20 can be increased by increasing the height H of the resonance units 20 and/or the size of the resonance units 20 in a plane perpendicular to the X-axis and the Y-axis, thereby enhancing the intensity of the acoustic wave signals generated by the resonance units 20.

In order to further improve the integration level of the bulk acoustic wave resonator component, the embodiment of the invention further provides the following technical scheme:

fig. 6 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 7 is a schematic top view of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 8 is a schematic view showing a sectional structure of the bulk acoustic wave resonator assembly shown in fig. 7 in A1-A2 direction. Fig. 9 is a topology of the bulk acoustic wave resonator assembly shown in fig. 7. FIG. 10 is a junction of yet another bulk acoustic wave resonator assembly according to an embodiment of the present inventionSchematic top view of the structure. Fig. 11 is a schematic view showing a sectional structure of the bulk acoustic wave resonator assembly shown in fig. 10 in the direction B1-B2. Fig. 12 is a topology of the bulk acoustic wave resonator assembly shown in fig. 10. Fig. 13 is a schematic structural diagram of yet another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 14 is a topology of the bulk acoustic wave resonator assembly shown in fig. 13. Taking fig. 6, 8, 11 and 13 as an example, the number of the substrates 10 in the bulk acoustic wave resonator assembly is p, wherein in the thickness direction parallel to the substrates 10, the p substrates 10 are parallel and are arranged at intervals, and the value of p comprises an integer greater than or equal to 1; the first surface 10A and/or the second surface 10B of the r-th substrate 10 opposite to the first surface 10A is provided with Q _r The resonance units 20, r have an integer of 1 or more and p or less, Q _r The values of (2) include integers greater than or equal to 1; the bulk acoustic wave resonator assembly further comprises a conductive interconnect structure 30 and a carrier plate 40, the carrier plate 40 being located on the first surface 10A side of the p-th substrate 10, the conductive interconnect structure 30 being adapted to draw electrical signals of the resonator element 20 out to the surface of the carrier plate 40 facing away from the p-th substrate 10, and/or the conductive interconnect structure 30 being adapted to draw electrical signals of the resonator element 20 out to the second surface 10B side of the 1-th substrate 10.

The carrier 40 and the substrate 10 may be made of the same material or different materials.

Alternatively, referring to fig. 6, 8, 11 and 13, the conductive interconnect structure 30 includes: at least one of a conductive via 31, a conductive bonding layer 32, a PAD (PAD) 33, and a rewiring layer 34; referring to fig. 13, the conductive via 31 in the substrate 10 is used to transfer an electrical signal from the first surface 10A of the substrate 10 to the second surface 10B. Referring to fig. 6, 8, 11 and 13, the conductive vias 31 in the carrier plate 40 are used to transfer electrical signals adjacent to the surface of the substrate 10 to the surface facing away from the substrate 10. The conductive bonding layer 32 is located between the two adjacent substrates 10 and between the substrate 10 and the carrier 40, and is used for fixing the two adjacent substrates 10 and the substrate 10 and the carrier 40. And the projection of the conductive bonding layer 32 on the substrate 10 covers part or all of the conductive through holes 31, and the projection of the conductive bonding layer 32 on the carrier 40 covers part or all of the conductive through holes 31. The resonance unit 20 is located in the enclosed space surrounded by the conductive bonding layer 32, the two adjacent substrates 10, and the substrates 10 and the carrier 40. A PAD (PAD) 33 is located on the first surface 10A and/or the second surface 10B of the r-th substrate 10, and a projection of the PAD (PAD) 33 on the substrate 10 covers part or all of the conductive via 31; the redistribution layer 34 is located on a surface of the carrier 40 facing away from the substrate 10, and a projection of the redistribution layer 34 on the p-th substrate 10 covers part or all of the conductive vias 31 disposed in the p-th substrate. The conductive interconnection structure 30 is used for leading out the electrical signal of the resonant unit 20 to the surface of the carrier 40 facing away from the p-th substrate 10. It should be noted that, although the drawings in the present embodiment are not shown, the present embodiment further includes the following technical solutions: a conductive via 31 may be provided in the 1 st substrate 10, and a redistribution layer 34 may be provided on the second surface of the 1 st substrate 10, so that the conductive interconnect structure 30 is used to draw out the electrical signal of the resonant cell 20 to the second surface 10B side of the 1 st substrate 10. Specifically, the conductive interconnection structure 30 is configured to draw out an electrical signal of the resonant unit 20 to a surface of the carrier 40 facing away from the p-th substrate 10, and/or the conductive interconnection structure 30 is configured to draw out an electrical signal of the resonant unit 20 to a second surface 10B side of the 1 st substrate 10, so as to electrically connect the electrical signal of the bulk acoustic wave resonator assembly with a compensation circuit formed by at least one of a capacitance, an inductance, a resistance, and a functional chip. Optionally, the conductive bonding layer 32 is used for bonding different substrates 10 and the carrier 40, and the edges of the substrates 10 and the carrier 40 are provided with the sealed conductive bonding layer 32, so as to form a sealed space surrounded by the conductive bonding layer 32, two adjacent substrates 10 and the carrier 40. Optionally, the enclosed space is a vacuum enclosed space. The vacuum enclosure is used to reflect sound waves back to the resonant unit 20, thereby reducing the loss of sound waves.

Illustratively, in the bulk acoustic wave resonator assembly shown in fig. 6, p has a value of 1. In a thickness direction parallel to the substrate 10, the first surface 10A of the substrate 10 is provided with 2 resonance units 20. The conductive interconnection structure 30 is located on the surface and/or inside of the substrate 10 and the carrier 40, each resonant unit 20 is electrically connected to the conductive interconnection structure 30, and the conductive interconnection structure 30 is used for leading out the electrical signal of the resonant unit 20 to the surface of the carrier 40 facing away from the 1 st substrate 10.

Illustratively, in the bulk acoustic wave resonator assembly shown in fig. 8, p has a value of 1. In a thickness direction parallel to the substrate 10, the first surface 10A of the substrate 10 is provided with 4 resonance units 20. The 4 resonant cells 20 are divided into 2 groups, each group is internally provided with 2 resonant cells 20 connected in series, and the conductive interconnection structure 30 respectively leads out electric signals of the two groups of resonant cells 20 to the surface of the carrier plate 40, which is far away from the 1 st substrate 10.

Illustratively, in the bulk acoustic wave resonator assembly shown in fig. 11, p has a value of 1. In a thickness direction parallel to the substrate 10, the first surface 10A of the substrate 10 is provided with 3 resonance units 20. The 3 resonance units 20 are connected in series. The conductive interconnection structures 30 respectively lead out the electrical signals of the 3 series-connected resonance units 20 to the surface of the carrier plate 40 facing away from the 1 st substrate 10.

Illustratively, in the bulk acoustic wave resonator assembly shown in fig. 13, p has a value of 2. In the thickness direction parallel to the substrates 10, 2 substrates 10 are arranged in parallel and at intervals. The carrier 40 is parallel to and spaced apart from the 2 nd substrate 10. The first surface 10A of the 1 st substrate 10 is provided with 3 resonance units 20. The first surface 10A of the 2 nd substrate 10 is provided with 2 resonance units 20. The second surface 10B of the 2 nd substrate 10 is provided with 2 resonance units 20. The conductive interconnection structure 30 is located on the surface and/or inside of the substrate 10 and the carrier 40, and the conductive interconnection structure 30 is used for leading out the electrical signal of the resonant unit 20 to the surface of the carrier 40 facing away from the 2 nd substrate 10.

Note that, in this embodiment, the value of p is not limited to 1 or 2, and an integer greater than or equal to 1 may be selected.

It should be further noted that, referring to fig. 8, 11 and 13, the conductive interconnection structure 30 is located on the surface and/or inside of the substrate 10 and the carrier 40, and the resonant cells 20 may be connected in series and then electrically connected to the conductive interconnection structure 30, where the conductive interconnection structure 30 is used to draw out an electrical signal of the resonant cell 20 to the surface of the carrier 40 facing away from the p-th substrate 10. In this embodiment, the connection manner between the resonance units 20 may be specifically set according to the actual situation.

Specifically, the present embodimentThe bulk acoustic wave resonator assembly provided in the example includes a carrier 40, a conductive interconnection structure 30, and p parallel and spaced substrates 10, where the value of p includes an integer greater than or equal to 1. The first surface 10A and/or the second surface 10B of the r-th substrate 10 opposite to the first surface 10A is provided with Q _r The conductive interconnection structure 30 is used for leading out the electrical signal of the resonance unit 20 to the surface of the carrier plate 40 facing away from the p-th substrate 10. The above technical solution increases the number of vertically arranged resonant units 20 that can be stacked in the thickness direction parallel to the substrate 10 on the basis of reducing the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10, being favorable for forming a miniaturized and highly integrated bulk acoustic wave resonator assembly and a communication device formed by the bulk acoustic wave resonator assembly, and further improving the integration of the bulk acoustic wave resonator assembly and the communication device. The conductive interconnection structure 30 is used for leading out an electrical signal of the resonant unit 20 to a surface of the carrier 40 facing away from the p-th substrate 10, and/or the conductive interconnection structure 30 is used for leading out an electrical signal of the resonant unit 20 to a second surface 10B side of the 1 st substrate 10, so as to facilitate the electrical connection of the electrical signal of the bulk acoustic wave resonator assembly and a compensation circuit composed of at least one of capacitance, inductance, resistance and a functional chip.

In order to further avoid the loss of the acoustic wave signals emitted by the substrate 10 and/or the carrier 40 to the resonance unit 20, the embodiment of the present invention further provides the following technical solutions:

optionally, on the basis of the above technical solution, the height of the resonant unit 20 is smaller than the spacing between the adjacent substrates 10, or the height of the resonant unit 20 is smaller than the spacing between the p-th substrate 10 and the carrier 40.

In particular, referring to fig. 6, the height of the resonance unit 20 is smaller than the interval between the adjacent substrates 10. Referring to fig. 13, a bulk acoustic wave resonator assembly is shown in which the height of the resonant cells 20 is less than the spacing between the p-th substrate 10 and the carrier plate 40. Taking fig. 6 as an example for illustration, the above technical solution may ensure that the first cavity structure 20a exists between the resonant unit 20 and the substrate 10 or between the resonant unit 20 and the carrier 40, in the thickness direction parallel to the substrate 10, the dimension H1 of the first cavity structure 20a between the resonant unit 20 and the substrate 10 is the difference between the distance between adjacent substrates 10 and the height of the resonant unit 20, and the dimension H1 of the first cavity structure 20a between the resonant unit 20 and the carrier 40 is the difference between the distance between the p-th substrate 10 and the carrier 40 and the height of the resonant unit 20. The first cavity structure 20a has small loss for sound waves, especially transverse waves, and can reflect the sound waves, especially transverse waves, back to the resonance unit 20, so that the performance of the resonance unit 20 is improved. Illustratively, the dimension H1 of the first cavity structure 20a is greater than or equal to 10 microns. Note that, in the bulk acoustic wave resonator assembly shown in fig. 6, the value of p is 1, and only the bulk acoustic wave resonator assembly in which the height of the resonant unit 20 is smaller than the pitch between the p-th substrate 10 and the carrier 40 is shown. In the bulk acoustic wave resonator assembly shown in fig. 13, p has a value of 2, and the height of the resonant unit 20 is smaller than the space between the adjacent substrates 10, and the height of the resonant unit 20 is smaller than the space between the p-th substrate 10 and the carrier 40.

Optionally, based on the above technical solution, in the bulk acoustic wave resonator assembly, in the resonant units 20 on the same surface of the r substrate 10, the k1 resonant unit 20 and the k2 resonant unit 20 are adjacently arranged, and the value of k1 is greater than or equal to 1 and less than Q _r The value of k2 includes an integer greater than or equal to 1 and less than Q _r Is an integer of (2); the kth 1 resonance unit 20 is disposed adjacent to the homonymous electrode of the kth 2 resonance unit 20; and/or the kth 1 resonant unit 20 is disposed adjacent to the synonym electrode of the kth 2 resonant unit 20.

Specifically, the kth 1 resonant cell 20 is disposed adjacent to the electrode of the kth 2 resonant cell 20, that is, the kth 1 resonant cell 20 is disposed adjacent to the first electrode 21 of the kth 2 resonant cell 20 or the kth 1 resonant cell 20 is disposed adjacent to the second electrode 23 of the kth 2 resonant cell 20. The kth 1 resonant cell 20 is disposed adjacent to the synonym electrode of the kth 2 resonant cell 20, i.e., the first electrode 21 of the kth 1 resonant cell 20 is disposed adjacent to the second electrode 23 of the kth 2 resonant cell 20, or the second electrode 23 of the kth 1 resonant cell 20 is disposed adjacent to the first electrode 21 of the kth 2 resonant cell 20.

Note that, in the structural schematic diagram of the bulk acoustic wave resonator assembly in this embodiment, the case where the kth 1 st resonator unit 20 and the kth 2 nd resonator unit 20 are adjacently disposed are shown, but in this embodiment, it is not limited whether the two adjacent resonator units 20 are adjacently disposed with the same name electrode or with different name electrodes, and flexibility of the film layer arrangement sequence of the first electrode 21, the piezoelectric layer 22, and the second electrode 23 in the resonator units 20 is increased. Whether the two adjacent resonance units 20 are arranged adjacently to the same-name electrode or adjacently to the different-name electrode, the conductive interconnection structure 30 can be reasonably arranged, so that the conductive interconnection structure 30 can lead out the electric signals of the resonance units 20 to the surface of the carrier plate 40, which is away from the p-th substrate 10, and/or to the second surface 10B side of the 1 st substrate 10.

In order to facilitate electrical connection between different resonant cells 20, the embodiment of the present invention further provides the following technical solutions:

optionally, on the basis of the above technical solutions, referring to fig. 6, 8, 11 and 13, in the bulk acoustic wave resonator assembly, the bulk acoustic wave resonator assembly further includes a first horizontal connecting portion 21a and a second horizontal connecting portion 23a; the first horizontal connection portion 21a is connected to the first electrode 21, and forms an L-shape with the first electrode 21; the second horizontal connection portion 23a is connected to the second electrode 23, and forms an L-shape with the second electrode 23; in the same resonant cell 20, the piezoelectric layer 22 is located between the first electrode 21 and the second electrode 23.

Specifically, the piezoelectric layer 22 is located between the first electrode 21 and the second electrode 23 in one of the resonance units 20, and the first horizontal connection portion 21a and the second horizontal connection portion 23a are in contact with and electrically connected to the adjacent resonance unit 20, or the first horizontal connection portion 21a and the second horizontal connection portion 23a are directly in contact with and electrically connected to the conductive interconnection structure 30. Taking fig. 6 as an example for introduction, the arrangement of the first horizontal connection portion 21a and the second horizontal connection portion 23a makes the resonance unit 20 have the second cavity structure 20b in the thickness direction perpendicular to the substrate 10, and the second cavity structure 20b has small loss for sound waves, especially longitudinal waves, and can reflect the sound waves, especially longitudinal waves, back to the resonance unit 20, so as to further improve the performance of the resonance unit 20.

In the bulk acoustic wave resonator assembly, the technical scheme of realizing electrical connection of vertically arranged resonant units 20 in the resonant units 20 on the same surface of the r-th substrate 10 is further described below.

Alternatively, on the basis of the above technical solution, referring to fig. 6, 8, 11 and 13, when the kth 1 resonant unit 20 is disposed adjacent to the homonymous electrode of the kth 2 resonant unit 20 in the resonant units 20 on the same surface of the kth substrate 10, the homonymous electrodes of the kth 1 resonant unit 20 and the kth 2 resonant unit 20 are connected to form a U-shaped electrode, or the homonymous electrodes of the kth 1 resonant unit 20 and the kth 2 resonant unit 20 are electrically connected through the conductive interconnection structure 30.

Specifically, referring to fig. 8, 11 and 13, the same-name electrodes of the kth 1 and the kth 2 resonator units 20 that are adjacently disposed are connected to form a U-shaped electrode through the first horizontal connection portion 21a or the second horizontal connection portion 23a, so as to realize the serial connection of the two adjacent resonator units 20, and there is no need to provide a conductive interconnection structure 30 between the two adjacent resonator units 20, which further reduces the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10, and is beneficial to forming a miniaturized and highly integrated bulk acoustic wave resonator assembly and a communication device. Alternatively, the U-shaped electrodes of the kth 1 resonator unit 20 and the kth 2 resonator unit 20, which are adjacently disposed and connected by the same name electrode, may be obtained by patterning the same metal layer.

Referring to fig. 6 and 8, the kth 1 resonant cell 20 and the same-name electrode of the kth 2 resonant cell 20 which are adjacently arranged are electrically connected through the conductive interconnection structure 30, and in the process of forming the first electrode 21 and the second electrode 23 through patterning process through the same metal layer, the complexity of patterns on the mask is reduced, and the efficiency of preparing different resonant cells 20 is improved.

In the above technical solution, a technical solution for realizing electrical connection between two adjacent resonant units 20 is specifically described. The technical solution for electrically connecting two resonant cells 20 with a resonant cell 20 in between is specifically described below.

Optionally, based on the above technical solution, in the resonant units 20 on the same surface of the r substrate 10, at least one resonant unit 20 is spaced between the k3 rd resonant unit 20 and the k4 th resonant unit 20, where the value of k3 is greater than or equal to 1 and less than or equal to Q _r The value of k4 includes an integer greater than or equal to 1 and less than or equal to Q _r Is an integer of (2); the kth 3 resonant cell 20 is electrically connected with the homonymous electrode of the kth 4 resonant cell 20 through the conductive interconnection structure 30; alternatively, the kth 3 resonant cell and the synonym electrode of the kth 4 resonant cell are electrically connected by the conductive interconnect structure 30.

Specifically, in the resonance units 20 on the same surface of the r substrate 10, at least one resonance unit 20 is spaced between the k3 th resonance unit 20 and the k4 th resonance unit 20, and the homonymous electrode or the heteronymous electrode of the k3 rd resonance unit 20 and the k4 th resonance unit 20 are electrically connected through the conductive interconnection structure 30, so that electrical connection between two non-adjacent resonance units 20 is further realized. It should be noted that, in this embodiment, a corresponding schematic structural diagram is not shown.

Optionally, based on the above technical solution, referring to fig. 7 and 8, fig. 10 and 11, and fig. 13, in the resonant cells 20 on the same surface of the nth substrate 10, the suspended electrode 20C of the mth resonant cell 20 is connected with the conductive interconnection structure 30; the suspended electrode 20C of the mth resonance unit 20 includes a first electrode 21, and the second electrode 23 of the mth resonance unit 20 is electrically connected with the homonymous electrode or the heteronymous electrode of the nth resonance unit 20; alternatively, the suspended electrode 20C of the mth resonance unit 20 includes a second electrode 23, and the first electrode 21 of the mth resonance unit 20 is electrically connected with the same-name electrode or different-name electrode of the mth resonance unit 20, where the value of m is greater than or equal to 1 and less than or equal to Q _r The value of n includes an integer greater than or equal to 1 and less than or equal to Q _r And m and n are different in value.

Specifically, in the resonant cells 20 on the same surface of the r-th substrate 10, the suspended electrode 20C of the m-th resonant cell 20 is connected with the conductive interconnection structure 30, so as to realize electrical connection between the resonant cells 20 provided with the suspended electrode 20C between different substrates 10, and at least one of an input signal end and an output signal end, a capacitance, a resistance and an inductance in an equivalent circuit formed by a plurality of resonant cells 20 in the bulk acoustic wave resonator assembly.

Optionally, on the basis of the above technical solution, the connection relationship of the resonant units on the same surface of the r-th substrate 10 includes serial connection and/or parallel connection.

Referring to fig. 7 to 9, 10 to 12, and 13 to 14, the resonance units 20 of the same surface of the r-th substrate 10 are connected in series. Specifically, the resonance units 20 on the same surface of the same substrate 10 are connected in series, so that the connection relation of the resonance units 20 on the same surface of the same substrate 10 is simplified, the difficulty in layout of the conductive interconnection structure 30 and the resonance units 20 on the same surface of the same substrate 10 is further reduced, and the manufacturing cost of the bulk acoustic wave resonator assembly is further reduced.

In the bulk acoustic wave resonator assembly shown in fig. 10 and 11, the resonance units 20 on the same surface of the r-th substrate 10 are connected in series, for example. In the present embodiment, the resonant cells 20 including both series connection and parallel connection can also be provided on the same surface of the same substrate 10 by means of the conductive interconnection structure 30, and the number of the substrates 10 used can be reduced to reduce the size of the bulk acoustic wave resonator assembly in the thickness direction parallel to the substrate 10. Note that, in this embodiment, the connection relationship of the resonance units on the same surface of the r-th substrate 10 is not shown, and includes a schematic structure of series connection and parallel connection. In the embodiment of the invention, the resonant units 20 on the same surface of the same substrate 10 can be realized by means of the conductive interconnection structure 30 only in the technical scheme of parallel connection.

In order to further reduce the size of the bulk acoustic wave resonator assembly in the direction parallel to the thickness of the substrate 10, the following technical solutions are provided in the embodiments of the present invention:

optionally, referring to fig. 13, the resonant units 20 on the second surface 10B of the t-th substrate 10 and the resonant units 20 on the first surface of the t-1 th substrate 10 are distributed in an interdigital manner, where the value of t includes an integer greater than or equal to 2 and less than or equal to p.

Illustratively, p has a value of 2 and t has a value of 2. Specifically, the resonant cells 20 on the second surface 10B of the t-th substrate 10 and the resonant cells 20 on the first surface of the t-1 th substrate 10 are distributed in an interdigital manner, so that the size of the bulk acoustic wave resonator assembly in the direction parallel to the thickness of the substrate 10 can be reduced, and the bulk acoustic wave resonator assembly which is miniaturized and has high integration level and a communication device formed by the bulk acoustic wave resonator assembly can be formed.

Alternatively, on the basis of the above technical solution, referring to fig. 13, in a thickness direction perpendicular to the substrate 10, the different resonance units 20 are spaced apart by a first preset distance H2.

Specifically, in the thickness direction perpendicular to the substrate 10, the space between the different resonant cells 20 has small loss for sound waves, especially longitudinal waves, and can reflect sound waves, especially longitudinal waves, back to the resonant cells 20, thereby improving the performance of the resonant cells 20. Illustratively, the first predetermined distance H2 is greater than or equal to 10 microns.

Alternatively, on the basis of the above technical solution, referring to fig. 13, the resonance unit 20 is spaced from the adjacent structure by a second preset distance H3 in a direction parallel to the thickness of the substrate 10. It should be noted that, in the direction parallel to the thickness of the substrate 10, the structure adjacent to the resonance unit 20 may be any one of the substrate 10, the carrier 40, and the connection electrode or the conductive interconnection structure 30 between the resonance units 20.

Specifically, in the direction parallel to the thickness of the substrate 10, the space between the resonant unit 20 and the adjacent structure has small loss for sound waves, especially transverse waves, and can reflect sound waves, especially transverse waves, back to the resonant unit 20, thereby improving the performance of the resonant unit 20. Illustratively, the second predetermined distance H3 is greater than or equal to 10 microns.

It should be noted that, in the bulk acoustic wave resonator assembly shown in the embodiment of the present invention, the acoustic reflection structure 102 is disposed inside the substrate 10, but the embodiment of the present invention further includes a technical solution that the acoustic reflection structure 102 is disposed on the surface of the substrate 10.

The embodiment of the invention also provides a preparation method of the bulk acoustic wave resonator component. Fig. 15 shows a flow chart of a method of manufacturing a bulk acoustic wave resonator assembly. Fig. 16 to fig. 20 are schematic cross-sectional structures corresponding to steps of a method for manufacturing a bulk acoustic wave resonator assembly according to an embodiment of the present invention. Referring to fig. 15, the method of manufacturing the bulk acoustic wave resonator assembly includes the steps of:

step 110, providing a substrate, wherein at least one sound reflection structure is arranged on the surface or inside the substrate.

Taking fig. 2-4 as an example, a substrate 10 is provided. Illustratively, the substrate 10 may be selected from single crystal silicon, gallium arsenide, sapphire, quartz, and the like. Alternatively, referring to fig. 2-4, the acoustic reflection structure 102 includes any one of a cavity structure 102a, a bragg reflection layer 102b, and a backside via 102 c. Specifically, compared to the technical solution in which the bragg reflection layer 102b and the back via 102c are used as the acoustic reflection structure 102, the cavity structure 102a is used as a bulk acoustic wave resonator component of the acoustic reflection structure 102, and has the characteristics of higher quality factor, smaller loss and higher electromechanical coupling coefficient.

And 120, forming at least one resonance unit on the surface of the substrate, wherein the dimension of the resonance unit in the thickness direction perpendicular to the substrate is smaller than the dimension of the resonance unit in the thickness direction parallel to the substrate, the projection of the resonance unit on the substrate is at least partially overlapped with the projection of the acoustic reflection structure on the substrate, and the acoustic reflection structure is used for preventing transverse waves of the resonance unit from leaking to the substrate.

Referring to fig. 2 to 4, at least one resonance unit 20 is formed on the surface of the substrate 10, the size of the resonance unit 20 in the thickness direction perpendicular to the substrate 10 is smaller than the size of the resonance unit 20 in the thickness direction parallel to the substrate 10, and a gap between the resonance unit 20 and the resonance unit 20 can achieve an effect of reflecting the longitudinal wave back to the resonance unit 20, preventing the leakage of the longitudinal wave. At least one acoustic reflection structure 102 is arranged on the surface or inside the substrate 10, the projection of the resonance unit 20 on the substrate 10 is at least partially overlapped with the projection of the acoustic reflection structure 102 on the substrate 10, and the acoustic reflection structure 102 is used for preventing transverse waves in the resonance unit 20 from leaking to the substrate 10.

Optionally, when the cavity structure 102a is used as the acoustic reflection structure 102 to prevent the transverse wave of the resonant unit 20 from leaking to the substrate 10, the steps 110 and 120 include the following steps:

step 210, providing a substrate.

Referring to fig. 16, a substrate 10 is provided.

Step 220, at least one through hole is formed on the surface of the substrate.

Referring to fig. 17, at least one groove 103 is formed at the surface of the substrate 10.

Step 230, forming a sacrificial layer on the surface of the substrate and in the through hole.

Referring to fig. 18, a sacrificial layer 104 is formed on the surface of the substrate 10 and within the recess 103.

Step 240, removing the sacrificial layer on the surface of the substrate.

Referring to fig. 19, the sacrificial layer 104 of the surface of the substrate 10 is removed.

Step 250, forming at least one resonance unit on the surface of the substrate.

Referring to fig. 20, at least one resonance unit 20 is formed at the surface of the substrate 10.

Step 260, removing the sacrificial layer to form a cavity structure.

Referring to fig. 2, sacrificial layer 104 is removed to form cavity structure 102a.

Since the acoustic impedance of air is close to 0 and the acoustic impedance of the resonant cells 20 is relatively large, the mismatch of the interface impedances causes almost all of the acoustic waves, especially the transverse waves, transmitted to the cavity structure 102a to be reflected back to the resonant cells 20, so that the energy of the acoustic waves, especially the transverse waves, leaking out of the resonant cells 20 is extremely small, thereby playing a role of preventing the acoustic waves, especially the transverse waves, of the resonant cells 20 from leaking to the substrate 10.

Optionally, when the bragg reflection layer 102b is used as the acoustic reflection structure 102 to prevent the transverse wave of the resonant unit 20 from leaking to the substrate 10, the step 110 includes:

and forming grooves on the surface of the substrate, and forming Bragg reflection layers with high and low acoustic impedance layers alternately stacked in the grooves to form at least one Bragg reflection layer.

Referring to fig. 3, grooves are formed on the surface of the substrate 10, and bragg reflection layers 102b formed by alternately stacking high and low acoustic impedance layers are sequentially formed in the grooves to form at least one acoustic reflection preventing structure 102.

Optionally, when the back through hole 102c is used as the acoustic reflection structure 102 to prevent the transverse wave of the resonant unit 20 from leaking to the substrate 10, the step 110 includes:

a back surface through hole is formed on the surface of the substrate.

Referring to fig. 4, a back through hole 102c is formed at the surface of the substrate 10 to form at least one sound reflection structure 102.

Fig. 21 is a schematic flow chart included in step 120 in fig. 15. Fig. 22 to 24 are schematic cross-sectional structures corresponding to the steps of the preparation method included in step 120. Optionally, taking the bulk acoustic wave resonator assembly shown in fig. 5 as an example on the basis of the above technical solution, step 120 of forming at least one resonance unit on the surface of the substrate includes the following steps:

Step 1201, forming at least one piezoelectric layer on a surface of a substrate.

Referring to fig. 22, a thin film of the piezoelectric layer 22 may be grown on the surface of the substrate 10, and then at least one piezoelectric layer 22 may be formed by etching. By way of example, the piezoelectric layer 22 may be selected from at least one of a single crystal piezoelectric thin film material such as aluminum nitride, zinc oxide, lead zirconate titanate piezoelectric ceramic, lithium niobate, lithium tantalate, potassium niobate, and the like, and a polycrystalline piezoelectric thin film material. A proportion of rare earth elements may also be doped into the piezoelectric layer 22 to enhance the performance of the piezoelectric material layer.

Step 1202, at least one first electrode is formed on a surface of a substrate.

Referring to fig. 23, at least one first electrode 21 may be formed on the surface of the substrate 10 by a metal peeling method. The first electrode 21 may be exemplified by at least one of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, and titanium, which have good conductivity.

Step 1203, forming at least one second electrode on the surface of the substrate, wherein the resonance unit comprises a laminated structure of the first electrode, the piezoelectric layer and the second electrode in a thickness direction perpendicular to the substrate.

Referring to fig. 24, at least one second electrode 23 may be formed on the surface of the substrate 10 by a metal peeling method, wherein the resonance unit 20 includes a stacked structure of the first electrode 21, the piezoelectric layer 22, and the second electrode 23 in a thickness direction perpendicular to the substrate 10. The second electrode 23 may be, for example, at least one of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, and titanium, which have good conductivity.

Optionally, step 1203 is followed by removing the sacrificial layer.

Referring to fig. 5, sacrificial layer 104 is removed to form cavity structure 102a.

The above-described manufacturing method forms a laminated structure in which at least one resonance unit 20 is vertically arranged on the surface of the substrate 10, and in particular, the resonance unit 20 includes a first electrode 21, a piezoelectric layer 22, and a second electrode 23 in a thickness direction perpendicular to the substrate 10. Specifically, the resonant units 20 are vertically arranged on the surface of the substrate 10, and the dimension of the resonant units 20 perpendicular to the thickness direction of the substrate 10 is smaller than the dimension parallel to the thickness direction of the substrate 10, so that the dimension of the bulk acoustic wave resonator assembly perpendicular to the thickness direction of the substrate 10 is reduced, and the bulk acoustic wave resonator assembly and the communication device with small size and high integration level are formed. The resonance unit 20 and the gap between the resonance unit 20 can achieve an effect of reflecting the longitudinal wave in the acoustic wave back to the resonance unit 20, preventing the leakage of the longitudinal wave. The acoustic reflection structure 102 serves to prevent acoustic waves, in particular transverse waves, in the resonator element 20 from leaking to the substrate 10. Since the resonance units 20 are vertically arranged on the surface of the substrate 10, the area of the resonance units 20 can be increased by increasing the height H of the resonance units 20 and/or the size of the resonance units 20 in a plane perpendicular to the X-axis and the Y-axis, thereby enhancing the intensity of the acoustic wave signals generated by the resonance units 20.

The embodiment of the invention also provides a communication device, which comprises the bulk acoustic wave resonator component in any of the technical schemes; specifically, the communication device includes at least one of a filter, a duplexer, and a multiplexer.

In particular, at least two bulk acoustic wave resonator assemblies implement filters that pass signals in a certain frequency band by being connected in series and in parallel. A duplexer is simply understood to be the operation of two filters, one receiving filter to receive a signal and one transmitting filter to transmit a signal. A multiplexer can be understood simply as a communication device consisting of at least two diplexers.

The communication device provided by the embodiment of the invention comprises the bulk acoustic wave resonator assembly according to any of the above technical solutions, so that the communication device has the beneficial effects of the bulk acoustic wave resonator assembly, and is not described herein.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

1. A bulk acoustic wave resonator assembly comprising:

at least one resonance unit located on a surface of the substrate, the resonance unit having a smaller dimension in a thickness direction perpendicular to the substrate than the resonance unit in a thickness direction parallel to the substrate;

the projection of the resonance unit on the substrate is at least partially overlapped with the projection of the sound reflection structure on the substrate, and the sound reflection structure is used for preventing transverse waves of the resonance unit from leaking to the substrate;

in a thickness direction perpendicular to the substrate, the resonance unit includes a stacked structure of a first electrode, a piezoelectric layer, and a second electrode;

the number of the substrates is p, wherein in the thickness direction parallel to the substrates, the p substrates are arranged in parallel at intervals, and the value of the p comprises an integer greater than or equal to 1;

2. The bulk acoustic wave resonator assembly of claim 1 wherein the acoustic reflection structure comprises any one of a cavity structure, a bragg reflection layer, and a backside via.

3. The bulk acoustic wave resonator assembly of claim 1 wherein the size of the acoustic reflective structure in a thickness direction perpendicular to the substrate is greater than or equal to 0.2 microns and less than or equal to 3 microns.

4. The bulk acoustic wave resonator assembly of claim 1 wherein the height of the resonating unit is less than the spacing between adjacent substrates or the height of the resonating unit is less than the spacing between the p-th substrate and the carrier plate.

5. The bulk acoustic wave resonator assembly of claim 1, wherein, among the resonance units on the same surface of the r-th substrate, the k 1-th resonance unit and the k 2-th resonance unit are adjacently disposed, and the value of k1 is greater than or equal to 1 and less than Q _r The value of k2 is greater than or equal to 1 and less than Q _r Is an integer of (2);

6. The bulk acoustic wave resonator assembly of claim 5 further comprising a first horizontal connection, a second horizontal connection; the first horizontal connecting part is connected with the first electrode and forms an L shape with the first electrode; the second horizontal connecting part is connected with the second electrode and forms an L shape with the second electrode;

7. The bulk acoustic wave resonator assembly of claim 6 wherein, in the resonant cells on the same surface of the r-th substrate, when the k 1-th resonant cell is disposed adjacent to the k 2-th resonant cell, the k 1-th resonant cell and the k 2-th resonant cell are connected to form a U-shaped electrode, or the k 1-th resonant cell and the k 2-th resonant cell are electrically connected to each other by the conductive interconnection structure.

8. The bulk acoustic wave resonator assembly of claim 6 wherein, among the resonant cells on the same surface of the r-th substrate, at least one resonant cell is spaced between the k 3-th and k 4-th resonant cells, the value of k3 comprises 1 or more and Q or less _r The value of k4 is greater than or equal to 1 and less than or equal to Q _r Is an integer of (2);

9. The bulk acoustic wave resonator assembly according to any of claims 6-8, characterized in that in the resonance unit of the same surface of the r-th substrate, the suspended electrode of the m-th resonance unit is connected with the conductive interconnection structure;

10. The bulk acoustic wave resonator assembly of claim 1 wherein the connection of the resonating units on the same surface of the r-th substrate comprises a series connection and/or a parallel connection.

11. The bulk acoustic wave resonator assembly of claim 1 wherein the resonating elements of the second surface of the t-th substrate are interdigitated with the resonating elements of the first surface of the t-1 th substrate, wherein the value of t comprises an integer greater than or equal to 2 and less than or equal to p.

12. The bulk acoustic wave resonator assembly of claim 11 wherein different ones of the resonant cells are spaced apart by a first predetermined distance in a thickness direction perpendicular to the substrate.

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

forming at least one resonance unit on a surface of the substrate includes:

forming at least one piezoelectric layer on the surface of the substrate;

forming at least one first electrode on the surface of the substrate;

forming at least one second electrode on a surface of the substrate, wherein the resonance unit includes a stacked structure of the first electrode, the piezoelectric layer, and the second electrode in a thickness direction perpendicular to the substrate;

14. A communication device comprising a bulk acoustic wave resonator assembly according to any of claims 1-12;