CN113659953A

CN113659953A - Bulk acoustic wave resonator assembly, preparation method and communication device

Info

Publication number: CN113659953A
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: 2021-11-16
Anticipated expiration: 2041-08-12
Also published as: CN113659953B

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 acoustic reflection structure comprises a substrate, wherein at least one acoustic reflection structure is arranged on the surface or in the substrate; at least one resonance unit located on a surface of the substrate, a dimension of the resonance unit in a direction perpendicular to a thickness of the substrate being smaller than a dimension of the resonance unit in a direction parallel to the thickness of the substrate; the projection of the resonant unit on the substrate and the projection of the acoustic reflection structure on the substrate at least partially overlap, and the acoustic reflection structure is used for preventing the transverse wave of the resonant unit 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 sizes of the bulk acoustic wave resonator assembly and the communication device in the direction vertical to the thickness direction of the substrate are reduced, and the transverse waves of the resonance unit are prevented from leaking to the substrate through the acoustic reflection structure.

Description

Bulk acoustic wave resonator assembly, preparation 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 more and more widely applied.

A Film Bulk Acoustic Resonator (Film Bulk Acoustic Resonator), also called Bulk Acoustic Resonator (Bulk Acoustic wave), has the characteristics of small size, high working frequency, low power consumption, high quality factor, compatibility with CMOS process, etc., and has become an important device in the field of radio frequency communication and is widely applied at present.

The existing bulk acoustic wave resonator assembly comprises a substrate and at least one resonant unit, wherein the resonant 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 resonant unit. When the surface of the substrate is provided with at least one resonance unit, 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 of the substrate is too large, which is not favorable for forming the bulk acoustic wave resonator assembly and the communication device which are miniaturized and have high integration level, and the size of the acoustic reflection structure arranged on the surface of the substrate in the direction perpendicular to the thickness of the substrate is large, which reduces the firmness of the bulk acoustic wave resonator assembly.

Disclosure of Invention

In view of this, 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 size of the bulk acoustic wave resonator assembly and the size of the communication device in the direction perpendicular to the thickness direction of the substrate on the basis of improving the robustness of the device.

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

the acoustic reflection structure comprises a substrate, wherein at least one acoustic reflection structure is arranged on the surface or in the substrate;

at least one resonance unit located on a surface of the substrate, a dimension of the resonance unit in a thickness direction perpendicular to the substrate being smaller than a dimension of the resonance unit in a thickness direction parallel to the substrate, a vibration direction of a bulk acoustic wave of the resonance unit being perpendicular to a 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 acoustic reflection structure on the substrate, and the acoustic reflection structure is used for preventing the transverse wave 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 back via.

Optionally, in a direction perpendicular to the thickness of the substrate, the size of the acoustic reflection structure is greater than or equal to 0.2 micrometers and less than or equal to 3 micrometers.

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

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

the first surface and/or the second surface opposite to the first surface of the substrate of the r-th is provided with Q_rA resonance unit, wherein the value of r includes an integer greater than or equal to 1 and less than or equal to p, and Q_rValues of (a) 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 located on the first surface side of the p-th substrate, the conductive interconnection structure is used for leading out the electric signals of the resonance units to the surface of the carrier plate, which faces away from the p-th substrate, and/or the conductive interconnection structure is used for leading out the electric signals of the resonance units to the second surface side of the 1 st substrate.

Optionally, the height of the resonant unit is smaller than the distance between the adjacent substrates, or the height of the resonant unit is smaller than the distance between the pth substrate and the carrier.

Optionally, in the resonance unit on the same surface of the r-th substrate, the k1 th resonance unit and the k2 th resonance unit are adjacently arranged, and the value of k1 includes that k is greater than or equal to 1 and is less than Q_rThe value of k2 includes being greater than or equal to 1,and is less than Q_rAn integer of (d);

the k1 th resonance unit is arranged adjacent to the same-name electrode of the k2 th resonance unit; and/or the k1 th resonance unit is arranged adjacent to the synonym electrode of the k2 th resonance 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, when the kth 1 th resonance unit and the kth 2 th resonance unit in the resonance unit on the same surface of the substrate are adjacently arranged, the kth 1 th resonance unit and the kth 2 th resonance unit are connected to form a U-shaped electrode, or the kth 1 th resonance unit and the kth 2 th resonance unit are electrically connected to each other through the conductive interconnection structure.

Optionally, in the resonance unit on the same surface of the r-th substrate, at least one resonance unit is arranged between the k3 th resonance unit and the k4 th resonance unit, and the value of k3 includes that k is greater than or equal to 1 and is less than or equal to Q_rThe value of k4 includes being greater than or equal to 1 and less than or equal to Q_rAn integer of (d);

the electrodes of the resonance units of the k3 th resonance unit and the electrodes of the resonance units of the k4 th resonance unit are electrically connected through the conductive interconnection structure;

alternatively, the synonym electrodes of the k3 th resonance unit and the k4 th resonance unit are electrically connected through the conductive interconnection structure.

Optionally, in the resonance unit on the same surface of the substrate of the nth, the suspended electrode of the resonance unit of the mth is connected to the conductive interconnection structure;

the suspended 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 synonym electrode of the nth resonance unit;

or, the suspended 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 synonym 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_rN includes a value greater than or equal to 1 and less than or equal to Q_rAnd m and n have different values.

Optionally, the connection relationship of the resonance units on the same surface of the substrate of the r-th includes series connection and/or parallel connection.

Optionally, the resonant units on the second surface of the tth substrate and the resonant units on the first surface of the tth substrate are distributed in an interdigital manner, where a value of t includes an integer greater than or equal to 2 and less than or equal to p.

Optionally, in a direction perpendicular to the thickness direction of the substrate, the different resonant units are spaced by a first preset 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 in the substrate;

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

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

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

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

In the technical solution provided by this embodiment, the size of at least one resonance unit in the direction perpendicular to the thickness of the substrate is smaller than the size of the resonance unit in the direction parallel to the thickness of the substrate, so that the size of the bulk acoustic wave resonator assembly in the direction perpendicular to the thickness of the substrate is reduced, which is beneficial to forming a miniaturized bulk acoustic wave resonator assembly with high integration and a communication device formed by the bulk acoustic wave resonator assembly. The gap between the resonance unit and the resonance unit can reflect the longitudinal wave back to the resonance unit, and the effect of preventing the longitudinal wave from leaking is achieved. The projection of the acoustic reflection structure on the substrate is at least partially overlapped with the projection of the resonance unit on the substrate, and the acoustic reflection structure is used for preventing transverse waves in the resonance unit from leaking to the substrate, so that the loss of acoustic 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 direction vertical to the thickness of the substrate, the size of the acoustic reflection structure in the direction vertical to the thickness of 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 structural diagram of a bulk acoustic wave resonator assembly in 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 another bulk acoustic wave resonator assembly according to an embodiment of the present invention;

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

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 a bulk acoustic wave resonator assembly according to another embodiment of the present invention;

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

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

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

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

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

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

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

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

fig. 16-20 are schematic cross-sectional views illustrating 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 of FIG. 15;

fig. 22-24 are schematic cross-sectional views of the manufacturing method in step 120.

Detailed Description

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

As described in the above technical solution, 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 of the substrate is too large, which is not favorable for forming the bulk acoustic wave resonator assembly and the communication device with miniaturization and high integration, and the size of the acoustic reflection structure disposed on the surface of the substrate in the direction perpendicular to the thickness of the substrate is large, which reduces the firmness of the bulk acoustic wave resonator assembly. For this reason, fig. 1 is a schematic structural diagram of a bulk acoustic wave resonator assembly in the prior art. It should be noted that fig. 1 shows a cavity type bulk acoustic wave resonator assembly. The direction perpendicular to the thickness of the substrate 10 is defined as the X direction, and the direction parallel to the thickness of the substrate 10 is defined as the Y direction. 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 size of the resonance unit 20 perpendicular to the thickness direction of the substrate 10 is larger than the size parallel to the thickness direction of the substrate 10, which results in that the size of the bulk acoustic wave resonator assembly and the communication device constituted by the bulk acoustic wave resonator assembly in the direction 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 for forming a miniaturized and highly integrated bulk acoustic wave resonator assembly and communication device. It should be noted that the most basic structure of the bulk acoustic wave resonator is a sandwich structure formed by two electrodes sandwiching the piezoelectric layer 22, and under the action of the alternating electric field of the first electrode 21 and the second electrode 23, the piezoelectric layer 22 will deform, and microscopically represents the vibration of phonon, and macroscopically forms the acoustic wave vibrating in the piezoelectric layer 22. 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 transverse waves will still be present. In the longitudinal wave, the moving direction of the particles and the propagation direction of the sound wave are parallel, but each particle does not move along the direction of the sound wave, but vibrates back and forth in its respective equilibrium state. In transverse waves, the direction of motion of the particles and the direction of propagation of the sound wave are perpendicular to each other. The particles do not move in the propagation direction of the acoustic wave, but vibrate up and down in their respective equilibrium states. The longitudinal wave among the acoustic waves of the related art resonance unit 20 propagates mainly in a direction parallel to the thickness direction of the substrate 10, and thus the related art acoustic reflection structure is to prevent the longitudinal wave from leaking to the substrate 10. Illustratively, the acoustically reflective structure in FIG. 1 is a cavity structure 101. And the size of the bulk acoustic wave resonator component and the communication device formed by the bulk acoustic wave resonator component in the direction vertical to the thickness of the substrate 10 is larger, and the cavity structure 101 is used as an acoustic reflection structure, and the size of the cavity structure 101 needs to be matched with the resonance unit 20, so that the size of the cavity structure 101 in the direction vertical to the thickness of the substrate 10 is also larger, and further the built-in cavity structure 101 arranged on the surface of the substrate 10 reduces the firmness of the bulk acoustic wave resonator component.

In view of the above technical problems, an embodiment of the present invention provides the following technical solutions:

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 to 4, the bulk acoustic wave resonator assembly includes: a substrate 10, at least one sound reflection structure 102 is arranged on the surface or inside of the substrate 10; 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 at least partially coincides 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 resonance unit 20 from leaking to the substrate 10.

For example, fig. 2 to 4 show a technical solution that the projection of the resonant unit 20 on the substrate 10 completely coincides with the projection of the acoustic reflection structure 102 on the substrate 10. The embodiment of the present invention further includes a technical solution that the projection of the resonant unit 20 on the substrate 10 coincides with the projection 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 defined as the X direction, and the direction parallel to the thickness direction of the substrate 10 is defined as the Y direction. A dimension of the resonance unit 20 in the thickness direction perpendicular to the substrate 10 is smaller than a dimension of the resonance unit 20 in the thickness direction parallel to the substrate 10, and a longitudinal wave among the acoustic waves of the resonance unit 20 propagates mainly in the thickness direction perpendicular to the substrate 10. The transverse wave of the acoustic waves of the resonance unit 20 propagates mainly in the direction parallel to the thickness of the substrate 10. The gap between the resonant unit 20 and the resonant unit 20 in the embodiment of the invention can reflect the longitudinal wave back to the resonant unit 20, thereby preventing the leakage of the longitudinal wave. In the conventional bulk acoustic wave resonator assembly shown in fig. 1, the cavity structure 101 can reflect the longitudinal wave back to the resonant unit 20, thereby preventing the leakage of the longitudinal wave. It is known that the leakage of the transverse wave of the resonant unit 20 to the substrate 10 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 of the substrate 10, the projection of the resonant unit 20 on the substrate 10 at least partially coincides with the projection of the acoustic reflection structure 102 on the substrate 10, and the acoustic reflection structure 102 is used to prevent the transverse wave in the resonant unit 20 from leaking to the substrate 10.

Optionally, the acoustic reflection structure 102 includes any one of a cavity structure 102a, a bragg reflection layer 102b, and a backside via hole 102 c. The back 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 the acoustic reflection structure 102 for preventing the acoustic wave, particularly the transverse wave, in the resonance unit 20 from leaking to the substrate 10. Shown in fig. 4 is a back surface through hole 102c as a means for preventing the acoustic wave, particularly the transverse wave, in the resonance unit 20 from leaking to the substrate 10. Since the acoustic impedance of air is close to 0 and the acoustic impedance of the resonant cell 20 is large, such an interface impedance mismatch causes almost all of the acoustic wave, particularly the transverse wave, transmitted to the cavity structure 102a or the back surface via hole 102c to be reflected back to the resonant cell 20, so that the energy of the acoustic wave, particularly the transverse wave, leaking out of the resonant cell 20 is extremely small, thereby achieving an effect of preventing the acoustic wave, particularly the transverse wave, of the resonant cell 20 from leaking to the substrate 10.

Shown in fig. 3 is a bragg reflection layer 102b as the acoustic reflection structure 102 for preventing the acoustic wave, particularly the transverse wave, in the resonance unit 20 from leaking to the substrate 10. The bragg reflector 102b uses bragg reflectors formed by alternately stacking high and low acoustic impedance layers to prevent the transverse wave of the resonant unit 20 from leaking to the substrate 10, the thickness of each acoustic impedance layer is greater than 1/4 wavelengths, and the larger the acoustic impedance ratio of the high and low acoustic impedance layers, the better the effect of the bragg reflector 102b in preventing the acoustic wave of the resonant unit 20, especially the transverse wave, from leaking to the substrate 10 is.

Specifically, compared with the technical scheme that the bragg reflector layer 102b and the back through hole 102c are used as the acoustic reflection structure 102, the bulk acoustic wave resonator component with the cavity structure 102a as the acoustic reflection structure 102 has the characteristics of higher quality factor, smaller loss and higher electromechanical coupling coefficient.

In the solution provided in this embodiment, the size of at least one 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, so that the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10 is reduced, which is beneficial to forming a miniaturized bulk acoustic wave resonator assembly with high integration level and a communication device formed by the bulk acoustic wave resonator assembly. The gap between the resonance unit 20 and the resonance unit 20 can achieve the effect of reflecting the longitudinal wave back to the resonance unit 20 and preventing the leakage of the longitudinal wave. The projection of the acoustic reflection structure 102 on the substrate 10 at least partially overlaps the projection of the resonant unit 20 on the substrate 10, and the acoustic reflection structure 102 is used for preventing the transverse wave in the resonant unit 20 from leaking to the substrate 10, thereby reducing the loss of the acoustic wave. And the size of the acoustic reflection structure 102 needs to match with the resonance unit 20, and as the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10 decreases, the size of the acoustic reflection structure 102 in the thickness direction perpendicular to the substrate 10 is in a smaller range, thereby improving the firmness of the bulk acoustic wave resonator assembly.

Optionally, the size of the acoustic reflection structure 102 in the direction perpendicular to the thickness direction of the substrate 10 is greater than or equal to 0.2 micrometers and less than or equal to 3 micrometers.

Specifically, the size of the acoustic reflection structure 102 is less than 0.2 μm in the thickness direction perpendicular to the substrate 10, and is less effective in preventing the acoustic wave, particularly the transverse wave, of the resonant unit 20 from leaking to the substrate 10. The dimensions of the cavity structures 102a and the back through holes 102c in the direction perpendicular to the thickness direction of the substrate 10 are greater than 3 micrometers, which results in excessive material removal from the substrate 10, and thus insufficient support strength of the substrate 10, and reduced firmness of the bulk acoustic wave resonator assembly. The size of the bragg reflector 102b in the thickness direction perpendicular to the substrate 10 is greater than 3 microns, and the pressure of the bragg reflector 102b on the substrate 10 is too large, 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 the preset requirement. Preferably, the size of the acoustic reflection structure 102 may be any one of 1.1 micrometers, 1.2 micrometers, 1.3 micrometers, or 1.6 micrometers in a direction perpendicular to the thickness direction of the substrate 10.

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

The following describes the arrangement of the resonant units 20 on the surface of the substrate 10. 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 the thickness direction perpendicular to the substrate 10, the resonance unit 20 includes a laminated structure of the first electrode 21, the piezoelectric layer 22, and the second electrode 23.

The working principle of the resonance unit 20 in this embodiment is as follows: under the action of the alternating electric field of the first electrode 21 and the second electrode 23, the piezoelectric layer 22 is deformed, microscopically showing the vibration of phonon, macroscopically forming the acoustic wave vibrating in the piezoelectric layer 22. The gap between the resonant unit 20 and the resonant unit 20 can reflect the longitudinal wave in the sound wave back to the resonant unit 20, thereby preventing the leakage of the longitudinal wave. The acoustic reflection structure 102 serves to prevent the acoustic wave, particularly the transverse wave, in the resonance unit 20 from leaking to the substrate 10. Since the resonant units 20 are vertically arranged on the surface of the substrate 10, the area of the resonant unit 20 can be increased by increasing the height H of the resonant unit 20 and/or the size of the resonant unit 20 in the plane perpendicular to the X axis and the Y axis, so as to enhance the intensity of the acoustic wave signal generated by the resonant unit 20.

In order to further improve the integration level of the bulk acoustic wave resonator component, the embodiment of the invention also 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 sectional structure view in the a1-a2 direction of the bulk acoustic wave resonator assembly shown in fig. 7. Fig. 9 is a topological view of the bulk acoustic wave resonator assembly shown in fig. 7. Fig. 10 is a schematic top view of a structure of a bulk acoustic wave resonator assembly according to another embodiment of the present invention. Fig. 11 is a schematic sectional structure view of the bulk acoustic wave resonator assembly shown in fig. 10 in the direction B1-B2. Fig. 12 is a topological view of the bulk acoustic wave resonator assembly shown in fig. 10. Fig. 13 is a schematic structural diagram of another bulk acoustic wave resonator assembly according to an embodiment of the present invention. Fig. 14 is a topological view of the bulk acoustic wave resonator assembly shown in fig. 13. Taking fig. 6, 8, 11 and 13 as an example, in the bulk acoustic wave resonator assembly, the number of the substrates 10 is p, wherein, in the thickness direction parallel to the substrates 10, the p substrates 10 are arranged in parallel and at intervals, and 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 are provided with Q_rThe value of each resonant unit 20, r includes an integer greater than or equal to 1 and less than or equal to p, Q_rValues of (a) include integers greater than or equal to 1; the bulk acoustic wave resonator assembly further comprises a conductive interconnection structure 30 and a carrier plate 40, the carrier plate 40 is located on the first surface 10A side of the p-th substrate 10, the conductive interconnection structure 30 is used for leading out the electric signals of the resonant unit 20 to the surface of the carrier plate 40 facing away from the p-th substrate 10, and/or the conductive interconnection structure 30 is used for leading out the electric signals of the resonant unit 20 to the second surface 10B side of the 1 st 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, conductive vias 31 in the substrate 10 are used to transmit electrical signals from the first surface 10A of the substrate 10 to the second surface 10B. Referring to fig. 6, 8, 11 and 13, conductive vias 31 within carrier plate 40 are used to convey electrical signals adjacent to the surface of substrate 10 to the surface facing away from substrate 10. The conductive bonding layer 32 is located between 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 resonant unit 20 is located in a closed space enclosed by the conductive bonding layer 32, two adjacent substrates 10, and the substrate 10 and the carrier 40. A PAD (PAD)33 is positioned on the first surface 10A and/or the second surface 10B of the r-th substrate 10, and the projection of the PAD (PAD)33 on the substrate 10 covers part or all of the conductive through hole 31; the redistribution layer 34 is located on the surface of the carrier plate 40 facing away from the substrate 10, and the projection of the redistribution layer 34 on the p-th substrate 10 covers a part or all of the conductive through holes 31 arranged in the p-th substrate. The above-mentioned conductive interconnection structure 30 is used to lead out the electrical signal of the resonant unit 20 to the surface of the carrier plate 40 facing away from the p-th substrate 10. It should be noted that, although the drawings in this embodiment are not shown, this embodiment also includes the following technical solutions: the conductive via 31 may be provided inside the 1 st substrate 10, and the redistribution layer 34 may be provided on the second surface of the 1 st substrate 10, so that the conductive interconnection structure 30 is used to lead out the electrical signal of the resonant unit 20 to the second surface 10B side of the 1 st substrate 10. Specifically, the conductive interconnection structure 30 is configured to lead the electrical signal of the resonant unit 20 to a surface of the carrier plate 40 away from the p-th substrate 10, and/or the conductive interconnection structure 30 is configured to lead the electrical signal of the resonant unit 20 to a side of the second surface 10B of the 1 st substrate 10, so as to electrically connect the electrical signal of the bulk acoustic wave resonator assembly and the compensation circuit formed by at least one of the capacitor, the inductor, the resistor and the functional chip. Optionally, the conductive bonding layer 32 is used for bonding different substrates 10 and the substrate 10 and the carrier 40, and the edges of the substrate 10 and the carrier 40 are provided with the closed conductive bonding layer 32, which is used for forming a closed space enclosed by the conductive bonding layer 32, two adjacent substrates 10, and the substrate 10 and the carrier 40. Optionally, the enclosed space is a vacuum enclosed space. The vacuum enclosure is used to reflect the sound waves back to the resonant unit 20, thereby reducing the loss of the sound waves.

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

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

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

For example, 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 the 2 nd substrate 10 and spaced apart from the substrate. 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 interconnect structure 30 is located on the surface and/or inside of the substrate 10 and the carrier plate 40, and the conductive interconnect structure 30 is used for leading out the electrical signal of the resonant unit 20 to the surface of the carrier plate 40 facing away from the 2 nd substrate 10.

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

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 board 40, the resonant units 20 may be connected in series and then electrically connected to the conductive interconnection structure 30, and the conductive interconnection structure 30 is used for leading out the electrical signals of the resonant units 20 to the surface of the carrier board 40 facing away from the p-th substrate 10. In this embodiment, the connection mode between the resonant units 20 can be specifically set according to actual situations.

Specifically, the bulk acoustic wave resonator assembly provided in this embodiment includes a carrier plate 40, a conductive interconnection structure 30, and p substrates 10 arranged in parallel and at an interval, where a 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 are provided with Q_rAnd the conductive interconnection structure 30 is used for leading out the electric signals of the resonant unit 20 to the surface of the carrier plate 40, which faces away from the p-th substrate 10. According to the technical scheme, on the basis that the size of the bulk acoustic wave resonator assembly in the thickness direction perpendicular to the substrate 10 is reduced, 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 favorably formed, the number of the vertically arranged resonance units 20 which can be stacked in the thickness direction parallel to the substrate 10 is increased, and the integration level of the bulk acoustic wave resonator assembly and the communication device is further improved. The conductive interconnection structure 30 is used for leading out the electrical signal of the resonant unit 20 to the surface of the carrier plate 40 away from the p-th substrate 10, and/or the conductive interconnection structure 30 is used for leading out the electrical signal of the resonant unit 20 to the second surface 10B side of the 1 st substrate 10, so that the electrical signal of the bulk acoustic wave resonator assembly and the compensation circuit formed by at least one of the capacitor, the inductor, the resistor and the functional chip are electrically connected.

In order to further avoid the loss of the substrate 10 and/or the carrier plate 40 to the acoustic wave signal emitted by the resonant 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 distance between the adjacent substrates 10, or the height of the resonant unit 20 is smaller than the distance between the p-th substrate 10 and the carrier 40.

Specifically, referring to fig. 6, the height of the resonant cells 20 is smaller than the interval between the adjacent substrates 10. Referring to fig. 13, in the bulk acoustic wave resonator assembly, the height of the resonant unit 20 is less than the distance between the pth substrate 10 and the carrier plate 40. Taking fig. 6 as an example, the above technical solution can 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 direction parallel to the thickness direction of the substrate 10, a dimension H1 of the first cavity structure 20a between the resonant unit 20 and the substrate 10 is a difference between a distance between adjacent substrates 10 and a height of the resonant unit 20, and a dimension H1 of the first cavity structure 20a between the resonant unit 20 and the carrier 40 is a difference between a distance between a pth substrate 10 and the carrier 40 and a height of the resonant unit 20. The first cavity structure 20a not only has a small loss to the acoustic wave, especially the transverse wave, but also can reflect the acoustic wave, especially the transverse wave, back to the resonance unit 20, thereby improving the performance of the resonance unit 20. Illustratively, the dimension H1 of the first cavity structure 20a is greater than or equal to 10 microns. It should be noted 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 distance between the pth substrate 10 and the carrier plate 40 is shown. Fig. 13 shows a bulk acoustic wave resonator assembly in which p is 2, and the height of the resonant unit 20 is smaller than the distance between the adjacent substrates 10, and the height of the resonant unit 20 is smaller than the distance between the pth substrate 10 and the carrier 40.

Optionally, on the basis of the above technical solution, in the bulk acoustic wave resonator assembly, in the resonant units 20 on the same surface of the r-th substrate 10, the k 1-th resonant unit 20 and the k 2-th resonant unit 20 are adjacently disposed, and a value of k1 includes a value greater than or equal to 1 and less than Q_rK2 includes values greater than or equal to 1 and less than Q_rAn integer of (d); the k1 th resonance unit 20 is disposed adjacent to the same-name electrode of the k2 th resonance unit 20; and/or the k1 th resonant unit 20 andthe synonym electrodes of the k2 th resonant cell 20 are adjacently disposed.

Specifically, the k1 th resonant cell 20 is disposed adjacent to the same-name electrode of the k2 th resonant cell 20, that is, the k1 th resonant cell 20 is disposed adjacent to the first electrode 21 of the k2 th resonant cell 20 or the k1 th resonant cell 20 is disposed adjacent to the second electrode 23 of the k2 th resonant cell 20. The k1 th resonant cell 20 is disposed adjacent to the synonym electrode of the k2 th resonant cell 20, that is, the first electrode 21 of the k1 th resonant cell 20 is disposed adjacent to the second electrode 23 of the k2 th resonant cell 20, or the second electrode 23 of the k1 th resonant cell 20 is disposed adjacent to the first electrode 21 of the k2 th resonant cell 20.

It should be noted that, in the structural schematic diagram of the bulk acoustic wave resonator assembly in the present embodiment, a case where the k1 th resonant cell 20 and the k2 th resonant cell 20 which are adjacently arranged, but in the present embodiment, it is not limited whether the two adjacent resonant cells 20 are adjacently arranged with the same-name electrodes or the different-name electrodes, and flexibility of the arrangement sequence of the film layers of the first electrode 21, the piezoelectric layer 22, and the second electrode 23 in the resonant cells 20 is increased. No matter whether the two adjacent resonance units 20 are arranged with the same-name electrodes or the different-name electrodes, the conductive interconnection structure 30 can be reasonably arranged, so that the conductive interconnection structure 30 can lead the electric signals of the resonance units 20 to the surface of the carrier plate 40 deviating from the p-th substrate 10 and/or to the second surface 10B side of the 1 st substrate 10.

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

optionally, on the basis of the above technical solution, 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 23 a; the first horizontal connecting portion 21a is connected to the first electrode 21 and forms an L-shape with the first electrode 21; the second horizontal connecting portion 23a is connected with the second electrode 23 and forms an L shape with the second electrode 23; in the same resonator element 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 resonance cell 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 cell 20, or the first horizontal connection portion 21a and the second horizontal connection portion 23a are in direct contact with and electrically connected to the conductive interconnection structure 30. Taking fig. 6 as an example, the first horizontal connecting portion 21a and the second horizontal connecting portion 23a are disposed such that the resonant unit 20 has the second cavity structure 20b in the thickness direction perpendicular to the substrate 10, and the second cavity structure 20b not only has a small loss for the sound wave, especially the longitudinal wave, but also can reflect the sound wave, especially the longitudinal wave, back to the resonant unit 20, thereby improving the performance of the resonant unit 20.

In the bulk acoustic wave resonator assembly, the resonant units 20 arranged vertically in the resonant unit 20 on the same surface of the r-th substrate 10 are electrically connected.

Alternatively, on the basis of the above technical solution, referring to fig. 6, 8, 11 and 13, when the k1 th resonant unit 20 and the k2 th resonant unit 20 in the resonant unit 20 on the same surface of the r-th substrate 10 are adjacently disposed, the same-name electrodes of the k1 th resonant unit 20 and the k2 th resonant unit 20 are connected to form a U-shaped electrode, or the same-name electrodes of the k1 th resonant unit 20 and the k2 th resonant unit 20 are electrically connected through the conductive interconnection structure 30.

Specifically, referring to fig. 8, 11 and 13, the homonymous electrodes of the k1 th resonance unit 20 and the k2 th resonance unit 20 which are adjacently arranged 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 series connection of the two adjacent resonance units 20, and there is no need to arrange the conductive interconnection structure 30 between the two adjacent resonance units 20, thereby further reducing the size of the bulk acoustic wave resonator assembly in the direction perpendicular to the thickness direction of the substrate 10, and facilitating the formation of a miniaturized and highly integrated bulk acoustic wave resonator assembly and a communication device. Alternatively, U-shaped electrodes connecting the electrodes of the k1 th resonant cell 20 and the electrodes of the k2 th resonant cell 20, which are adjacently disposed, may be formed by patterning the same metal layer.

Referring to fig. 6 and 8, the electrodes of the resonance units 20 at the k1 th and the resonance units 20 at the k2 th 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 the same metal layer by the patterning process, the complexity of the patterns on the mask is reduced, and the efficiency of preparing different resonance units 20 is improved.

In the above technical solution, a technical solution of electrically connecting two adjacent resonance units 20 in time is specifically described. The following describes a technical solution for electrically connecting two resonant units 20 spaced apart from each other by a resonant unit 20.

Optionally, on the basis of the above technical solution, in the resonant units 20 on the same surface of the r-th substrate 10, at least one resonant unit 20 is spaced between the k 3-th resonant unit 20 and the k 4-th resonant unit 20, and the value of k3 includes that the value is greater than or equal to 1 and less than or equal to Q_rK4 includes values greater than or equal to 1 and less than or equal to Q_rAn integer of (d); the electrodes of the k3 th resonance unit 20 and the k4 th resonance unit 20 are electrically connected through the conductive interconnection structure 30; alternatively, the synonym electrodes of the k3 th resonance unit and the k4 th resonance unit are electrically connected through the conductive interconnection structure 30.

Specifically, in the resonant units 20 on the same surface of the r-th substrate 10, at least one resonant unit 20 is spaced between the k 3-th resonant unit 20 and the k 4-th resonant unit 20, and the same-name electrodes or different-name electrodes of the k 3-th resonant unit 20 and the k 4-th resonant unit 20 are electrically connected through the conductive interconnection structure 30, so that the two non-adjacent resonant units 20 are electrically connected. It should be noted that, in this embodiment, a corresponding structural schematic diagram is not shown.

Optionally, on the basis of the above technical solution, referring to fig. 7 and 8, fig. 10 and 11, and fig. 13, in the resonant unit 20 on the same surface of the r-th substrate 10, the floating electrode 20C of the m-th resonant unit 20 is connected to the conductive interconnection structure 30; the floating 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 synonym electrode of the nth resonance unit 20; or, the m-th harmonicThe floating electrode 20C of the resonant unit 20 includes a second electrode 23, the first electrode 21 of the mth resonant unit 20 is electrically connected to the homonymous electrode or the synonym electrode of the nth resonant unit 20, wherein the value of m includes being greater than or equal to 1 and being less than or equal to Q_rN includes a value greater than or equal to 1 and less than or equal to Q_rAnd m and n have different values.

Specifically, in the resonant units 20 on the same surface of the r-th substrate 10, the floating electrodes 20C of the m-th resonant unit 20 are connected to the conductive interconnection structure 30, so as to electrically connect the resonant units 20 provided with the floating electrodes 20C between different substrates 10, and to electrically connect at least one of an input signal terminal and an output signal terminal, a capacitor, a resistor, and an inductor in an equivalent circuit formed by a plurality of resonant units 20 in the bulk acoustic wave resonator assembly.

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

Referring to fig. 7 to 9, 10 to 12, and 13 to 14, the resonant cells 20 of the same surface of the r-th substrate 10 are connected in series. Specifically, the resonant units 20 on the same surface of the same substrate 10 are connected in series, which simplifies the connection relationship between the resonant units 20 on the same surface of the same substrate 10, and further reduces the difficulty in the layout of the conductive interconnection structure 30 and the resonant units 20 on the same surface of the same substrate 10, and further reduces the manufacturing cost of the bulk acoustic wave resonator assembly.

Illustratively, in the bulk acoustic wave resonator assembly shown in fig. 10 and 11, the resonant cells 20 on the same surface of the r-th substrate 10 are connected in series. In this embodiment, the resonant units 20 including both series connection and parallel connection may also be disposed on the same surface of the same substrate 10 by means of the conductive interconnection structure 30, and the number of substrates 10 used may be reduced to reduce the size of the bulk acoustic wave resonator assembly in the direction parallel to the thickness direction of the substrate 10. It should be noted 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 the connection relationship includes a schematic configuration diagram of series connection and parallel connection. In the embodiment of the present invention, it is also possible to realize that the resonant units 20 on the same surface of the same substrate 10 are only connected in parallel by means of the conductive interconnection structure 30.

In order to further reduce the size of the bulk acoustic wave resonator component in the direction parallel to the thickness of the substrate 10, the embodiment of the invention further provides the following technical scheme:

optionally, on the basis of the above technical solution, referring to fig. 13, the resonant cells 20 on the second surface 10B of the tth substrate 10 and the resonant cells 20 on the first surface of the tth-1 substrate 10 are distributed in an interdigital manner, where a 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 interdigital arrangement between the resonant cells 20 on the second surface 10B of the tth substrate 10 and the resonant cells 20 on the first surface of the t-1 th substrate 10 can reduce the size of the bulk acoustic wave resonator assembly in the direction parallel to the thickness of the substrate 10, which contributes to the formation of a miniaturized and highly integrated bulk acoustic wave resonator assembly and a communication device formed by the bulk acoustic wave resonator assembly.

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

Specifically, in the thickness direction perpendicular to the substrate 10, the space between different resonant units 20 has a small loss to the sound wave, especially the longitudinal wave, and can reflect the sound wave, especially the longitudinal wave, back to the resonant units 20, thereby improving the performance of the resonant units 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 resonant 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 the structure adjacent to the resonant unit 20 in the direction parallel to the thickness of the substrate 10 may be any one of the conductive interconnection structure 30 or the connection electrode between the substrate 10, the carrier plate 40 and the resonant unit 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 a small loss to the sound wave, especially the transverse wave, and can reflect the sound wave, especially the transverse wave, 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 particularly 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 also 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. Figure 15 shows a flow diagram of a method of making a bulk acoustic wave resonator assembly. Fig. 16-20 are schematic cross-sectional structures of the bulk acoustic wave resonator assembly according to the steps of the method for manufacturing the bulk acoustic wave resonator assembly according to the embodiment of the present invention. Referring to fig. 15, the method for 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.

By way of example, and as illustrated in fig. 2-4, a substrate 10 is provided. For example, the substrate 10 may be selected from monocrystalline silicon, gallium arsenide, sapphire, quartz, and the like. Alternatively, referring to fig. 2 to 4, the acoustic reflection structure 102 includes any one of a cavity structure 102a, a bragg reflection layer 102b, and a backside via hole 102 c. Specifically, compared with the technical scheme that the bragg reflector layer 102b and the back through hole 102c are used as the acoustic reflection structure 102, the bulk acoustic wave resonator component with the cavity structure 102a as the acoustic reflection structure 102 has the characteristics of higher quality factor, smaller loss and higher electromechanical coupling coefficient.

And 120, forming at least one resonant unit on the surface of the substrate, wherein the size of the resonant unit in the direction perpendicular to the thickness of the substrate is smaller than that of the resonant unit in the direction parallel to the thickness of the substrate, the projection of the resonant 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 the transverse wave of the resonant unit from leaking to the substrate.

Referring to fig. 2 to 4, at least one resonant unit 20 is formed on the surface of the substrate 10, the dimension of the 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, and the gap between the resonant unit 20 and the resonant unit 20 can reflect the longitudinal wave back to the resonant unit 20, thereby preventing the leakage of the longitudinal wave. The surface or the inside of the substrate 10 is provided with at least one acoustic reflection structure 102, the projection of the resonant unit 20 on the substrate 10 and the projection of the acoustic reflection structure 102 on the substrate 10 at least partially coincide, and the acoustic reflection structure 102 is used for preventing the transverse wave in the resonant unit 20 from leaking to the substrate 10.

Alternatively, 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 via is formed on the surface of the substrate.

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

And 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 resonant unit on the surface of the substrate.

Referring to fig. 20, at least one resonant unit 20 is formed on a surface of a substrate 10.

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

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

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

Optionally, when the bragg reflector 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, step 110 includes:

a groove is formed on the surface of the substrate, and Bragg reflection layers formed by alternately stacking high and low acoustic impedance layers are formed in the groove to form at least one Bragg reflection layer.

Referring to fig. 3, a groove is formed on a surface of a substrate 10, and bragg reflection layers 102b formed by alternately stacking high and low acoustic impedance layers are sequentially formed in the groove 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 backside via is formed on a surface of the substrate.

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

Fig. 21 is a schematic flow chart included in step 120 in fig. 15. Fig. 22-24 are schematic cross-sectional views of the manufacturing method in step 120. Optionally, on the basis of the above technical solution, taking the bulk acoustic wave resonator assembly shown in fig. 5 as an example, the step 120 of forming at least one resonant 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. For example, the piezoelectric layer 22 may be at least one of a single crystal piezoelectric thin film material and a polycrystalline piezoelectric thin film material, such as aluminum nitride, zinc oxide, lead zirconate titanate piezoelectric ceramic, lithium niobate, lithium tantalate, and potassium niobate. The piezoelectric layer 22 may also be doped with a proportion of a rare earth element to improve the performance of the piezoelectric material layer.

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

Referring to fig. 23, at least one first electrode 21 may be formed on the surface of the substrate 10 by a metal lift-off method. For example, the first electrode 21 may be made of 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 in a direction perpendicular to the thickness direction of the substrate, the resonance unit includes a laminated structure of the first electrode, the piezoelectric layer and the second electrode.

Referring to fig. 24, at least one second electrode 23 may be formed on the surface of the substrate 10 by a metal lift-off 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 direction perpendicular to the thickness direction of the substrate 10. For example, the second electrode 23 may be made of 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, the sacrificial layer 104 is removed to form a cavity structure 102 a.

The above-mentioned preparation method forms at least one resonant unit 20 vertically arranged on the surface of the substrate 10, specifically, in the thickness direction perpendicular to the substrate 10, the resonant unit 20 includes a laminated structure of a first electrode 21, a piezoelectric layer 22 and a second electrode 23. Specifically, the resonance units 20 are vertically arranged on the surface of the substrate 10, and the size of the resonance units 20 perpendicular to the thickness direction of the substrate 10 is smaller than the size of the resonance units 20 parallel to the thickness direction of the substrate 10, so that the size 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 which are small in size and high in integration level are favorably formed. The gap between the resonant unit 20 and the resonant unit 20 can reflect the longitudinal wave in the sound wave back to the resonant unit 20, thereby preventing the leakage of the longitudinal wave. The acoustic reflection structure 102 serves to prevent the acoustic wave, particularly the transverse wave, in the resonance unit 20 from leaking to the substrate 10. Since the resonant units 20 are vertically arranged on the surface of the substrate 10, the area of the resonant unit 20 can be increased by increasing the height H of the resonant unit 20 and/or the size of the resonant unit 20 in the plane perpendicular to the X axis and the Y axis, so as to enhance the intensity of the acoustic wave signal generated by the resonant unit 20.

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

Specifically, at least two bulk acoustic wave resonator components are connected in series and in parallel to realize a filter for passing signals in a certain frequency band. A duplexer can be simply understood as the operation of two filters, one receive filter to receive signals and one transmit filter to transmit signals. A multiplexer can be simply understood as a communication device formed by at least two duplexers.

The communication device provided by the embodiment of the present invention includes the bulk acoustic wave resonator component described in any of the above technical solutions, and therefore, the communication device has the beneficial effects of the bulk acoustic wave resonator component described above, and details are not repeated herein.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. 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, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A bulk acoustic wave resonator assembly, comprising:

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

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

3. The bulk acoustic wave resonator assembly of claim 1, wherein the size of the acoustic reflection structure in a direction perpendicular to the thickness of 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 according to claim 1, wherein the resonance unit includes a stacked structure of a first electrode, a piezoelectric layer, and a second electrode in a direction perpendicular to a thickness direction of the substrate.

5. The bulk acoustic wave resonator assembly according to claim 4, wherein the number of the substrates is p, wherein in the thickness direction parallel to the substrates, the p substrates are arranged in parallel and at intervals, and the value of p includes an integer greater than or equal to 1;

6. The bulk acoustic wave resonator assembly according to claim 5, wherein the height of the resonant unit is smaller than the spacing between adjacent substrates, or the height of the resonant unit is smaller than the spacing between the pth substrate and the carrier plate.

7. The bulk acoustic wave resonator assembly according to claim 5, wherein, of the resonance units on the same surface of the substrate, the k1 th resonance unit and the k2 th resonance unit are adjacently arranged, and the value of k1 includes 1 or more and less than Q_rK2 includes a value greater than or equal to 1 and less than Q_rAn integer of (d);

8. The bulk acoustic wave resonator assembly of claim 7, 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;

9. The bulk acoustic wave resonator assembly according to claim 8, wherein when the kth 1 resonant cells are disposed adjacent to the electrodes of the k2 resonant cells on the same surface of the substrate, the electrodes of the k1 resonant cells and the k2 resonant cells are connected to form U-shaped electrodes, or the electrodes of the k1 resonant cells and the k2 resonant cells are electrically connected through the conductive interconnection structure.

10. The bulk acoustic wave resonator assembly according to claim 8, wherein at least one resonant element is spaced between the kth 3 resonant element and the kth 4 resonant element in the r-th resonant element on the same surface of the substrate, and the value of k3 includes 1 or more and Q or less_rThe value of k4 includes being greater than or equal to 1 and less than or equal to Q_rAn integer of (d);

11. The bulk acoustic wave resonator assembly of any of claims 8-10, wherein in the resonant cells on the same surface of the substrate of the r-th, the floating electrodes of the m-th resonant cell are connected to the conductive interconnect structure;

12. The bulk acoustic wave resonator assembly according to claim 5, wherein the connection relationship of the resonance units on the same surface of the substrate of the r-th includes series connection and/or parallel connection.

13. The bulk acoustic wave resonator assembly according to claim 5, wherein the resonant elements on the second surface of the substrate t are distributed interdigital with the resonant elements on the first surface of the substrate t-1, and wherein t is an integer greater than or equal to 2 and less than or equal to p.

14. The bulk acoustic wave resonator assembly according to claim 13, wherein the different resonant units are spaced apart by a first predetermined distance in a direction perpendicular to a thickness direction of the substrate.

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

16. The method of manufacturing a bulk acoustic wave resonator assembly according to claim 15, wherein forming at least one resonant cell on the surface of the substrate comprises:

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

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

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

17. A communication device comprising the bulk acoustic wave resonator assembly of any one of claims 1-14;