Manufacturing method of temperature compensation type film bulk acoustic resonator

Abstract

The invention discloses a manufacturing method of a temperature compensation type film bulk acoustic resonator. The manufacturing method comprises the following steps: preparing a supporting structure; wherein the supporting structure comprises a substrate and an insulating layer which are arranged in a laminated manner, and a cavity penetrating through the insulating layer and at least part of the substrate; preparing a first temperature compensation unit and a first electrode of the transducer on the substrate; wherein the substrate comprises a substrate and a piezoelectric layer of the transducer which are arranged in a laminated manner, the piezoelectric layer, the first electrode and the first temperature compensation unit are arranged in a laminated manner, and the absolute value of the temperature-elastic coefficient of the first temperature compensation unit is smaller than that of the temperature-elastic coefficient of the piezoelectric layer; bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer; removing the substrate; and preparing a second electrode of the transducer on one side, far away from the first electrode, of the piezoelectric layer. According to the invention, the temperature drift coefficient of the film bulk acoustic resonator is reduced, the manufacturing difficulty is reduced, and the qualified rate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of resonators, and in particular to a method for manufacturing a temperature-compensated thin-film bulk acoustic wave resonator. Background Art

[0002] Using single crystal materials such as single crystal lithium niobate or single crystal aluminum nitride to prepare the piezoelectric layer is beneficial to improving the performance of the thin film bulk acoustic wave resonator.

[0003] However, there are the following problems: 1. It is difficult to produce piezoelectric layers made of single crystal materials such as single crystal lithium niobate or single crystal aluminum nitride with high quality using the existing metal organic chemical vapor deposition method. The production is difficult and the pass rate is low; 2. The temperature-elastic characteristics of the piezoelectric layer material will cause the temperature to have a negative impact on the performance of the thin film bulk acoustic wave resonator and the filter, that is, deteriorate the temperature drift coefficient (TCF) of the thin film bulk acoustic wave resonator and the filter. Summary of the invention

[0004] The present invention provides a method for manufacturing a temperature compensated thin film bulk acoustic wave resonator to solve the problems of high manufacturing difficulty, low qualified rate and high temperature drift coefficient of the manufactured thin film bulk acoustic wave resonator in the existing method for manufacturing the temperature compensated thin film bulk acoustic wave resonator.

[0005] An embodiment of the present invention provides a method for manufacturing a temperature-compensated thin film bulk acoustic resonator, the method comprising:

[0006] Preparing a support structure; wherein the support structure comprises a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate;

[0007] A first temperature compensation unit and a first electrode of a transducer are prepared on a substrate; wherein the substrate comprises a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and an absolute value of a temperature-elastic coefficient of the first temperature compensation unit is smaller than an absolute value of a temperature-elastic coefficient of the piezoelectric layer;

[0008] bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer;

[0009] removing the substrate;

[0010] A second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode.

[0011] Optionally, preparing a first temperature compensation unit and a first electrode of the transducer on a substrate includes:

[0012] Prepare the first electrode on a side of the piezoelectric layer away from the substrate;

[0013] Preparing a first temperature compensation layer of the first temperature compensation unit on a side of the first electrode away from the piezoelectric layer and a side of the piezoelectric layer away from the substrate;

[0014] Bonding the first temperature compensation unit and the insulating layer, comprising:

[0015] The first temperature compensation layer and the insulating layer are bonded.

[0016] Optionally, preparing a first temperature compensation unit and a first electrode of the transducer on a substrate includes:

[0017] Prepare a second temperature compensation layer of the first temperature compensation unit on a side of the piezoelectric layer away from the substrate;

[0018] preparing the first electrode on a side of the second temperature compensation layer away from the piezoelectric layer;

[0019] Bonding the first temperature compensation unit and the insulating layer, comprising:

[0020] The second temperature compensation layer and the insulating layer are bonded.

[0021] Optionally, after preparing the second temperature compensation layer of the first temperature compensation unit on a side of the piezoelectric layer away from the substrate, the manufacturing method further includes:

[0022] The second temperature compensation layer is patterned to obtain a bonding temperature compensation subsection and an electrode temperature compensation subsection that are isolated from each other; wherein the electrode temperature compensation subsection, the active area of ​​the transducer and the cavity overlap in a first direction, and the area of ​​the electrode temperature compensation subsection is larger than the area of ​​the active area and smaller than the area of ​​the cavity; the first direction is the thickness direction of the temperature-compensated thin film bulk acoustic resonator; the active area is the area where the first electrode overlaps with the second electrode along the first direction;

[0023] The first electrode is prepared on a side of the second temperature compensation layer away from the piezoelectric layer, comprising:

[0024] Prepare the first electrode on a side of the electrode temperature compensation section away from the piezoelectric layer;

[0025] Bonding the second temperature compensation layer and the insulating layer, comprising:

[0026] The bonding temperature compensation section and the insulating layer are bonded.

[0027] Optionally, after removing the substrate, the manufacturing method further comprises:

[0028] Prepare a third temperature compensation layer of a second temperature compensation unit on a side of the piezoelectric layer away from the first electrode;

[0029] The second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode, comprising:

[0030] The second electrode is prepared on a side of the third temperature compensation layer away from the piezoelectric layer.

[0031] Optionally, the manufacturing method further includes:

[0032] A passivation layer is prepared on a side of the transducer away from the support structure.

[0033] Optionally, the manufacturing method further includes:

[0034] A heat dissipation structure is prepared on a side of the passivation layer away from the transducer; wherein the heat dissipation structure and the active area of ​​the transducer do not overlap in a first direction; the first direction is the thickness direction of the temperature-compensated thin film bulk acoustic resonator; and the active area is the area where the first electrode and the second electrode overlap along the first direction.

[0035] Optionally, a heat dissipation structure is prepared on a side of the passivation layer away from the transducer, comprising:

[0036] Preparing a heat dissipation layer on a side of the passivation layer away from the transducer;

[0037] The heat dissipation layer is etched to form protrusions and grooves alternately arranged along the second direction and / or the third direction; wherein the first direction, the second direction and the third direction intersect each other.

[0038] Optionally, preparing a first temperature compensation unit and a first electrode of the transducer on a substrate includes:

[0039] Preparing a first temperature compensation unit and a first interdigital electrode of an interdigital transducer on the substrate;

[0040] The second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode, comprising:

[0041] A second interdigital electrode of the interdigital transducer is prepared on a side of the piezoelectric layer away from the first electrode.

[0042] Optionally, the material of the temperature compensation unit is the same as that of the insulation layer.

[0043] The technical solution of the embodiment of the present invention can reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator by setting a first temperature compensation unit and setting the absolute value of the temperature-elastic coefficient of the first temperature compensation unit to be smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer, which is beneficial to reducing the temperature drift coefficient (TCF) of the thin film bulk acoustic wave resonator and improving the stability of the thin film bulk acoustic wave resonator; by preparing the first temperature compensation unit and the first electrode of the transducer on a substrate including the transducer piezoelectric layer, and bonding the first temperature compensation unit and the insulating layer to realize the production of the temperature compensated thin film bulk acoustic wave resonator, it is beneficial to reduce the production difficulty and improve the qualified rate.

[0044] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of a preparation process of a support structure provided by an embodiment of the present invention;

[0048] Figure 3 A schematic diagram of a manufacturing process of a first temperature compensation unit and a first electrode of a transducer provided in an embodiment of the present invention;

[0049] Figure 4 A schematic diagram of a bonding process between a first temperature compensation unit and an insulating layer provided in an embodiment of the present invention;

[0050] Figure 5 A schematic diagram of a preparation process for removing a substrate provided in an embodiment of the present invention;

[0051] Figure 6 A schematic diagram of a manufacturing process of a second electrode of a transducer provided in an embodiment of the present invention;

[0052] Figure 7 A flow chart of another method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0053] Figure 8 A schematic diagram of another manufacturing process of a first temperature compensation unit and a first electrode of a transducer provided in an embodiment of the present invention;

[0054] Fig. 9 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0055] Fig.10 A schematic diagram of a manufacturing process of another first temperature compensation unit and a first electrode of a transducer provided in an embodiment of the present invention;

[0056] Fig.11 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0057] Fig.12 A schematic diagram of a manufacturing process of another first temperature compensation unit and a first electrode of a transducer provided in an embodiment of the present invention;

[0058] Fig.13 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0059] Fig.14 A schematic diagram of a preparation process of a third temperature compensation layer of a second temperature compensation unit provided in an embodiment of the present invention;

[0060] Fig.15 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0061] Fig.16 A schematic diagram of a process for preparing a passivation layer provided in an embodiment of the present invention;

[0062] Fig.17 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0063] Fig.18 A schematic diagram of a preparation process of a heat dissipation structure provided by an embodiment of the present invention;

[0064] Fig.19 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention;

[0065] Fig. 20 A schematic structural diagram of a temperature compensated Lamb wave resonator provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0067] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only used to illustrate the relative positional relationship between the components or components, and does not particularly limit the specific installation orientation of the components or components.

[0068] Figure 1 A flowchart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, referring to Figure 1 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0069] S110, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0070] For example, Figure 2 A schematic diagram of a preparation process of a support structure provided in an embodiment of the present invention, referring to Figure 2 Step S110 is specifically as follows: first, a wafer is provided, the wafer comprising a substrate 11 and an insulating layer 12 stacked along a first direction Z; then, a cavity 13 penetrating the insulating layer 12 and a portion of the substrate 11 is etched in the wafer, the area of ​​the cavity 13 is smaller than the area of ​​the insulating layer 12 and the substrate 11, and the cavity 13 is defined by the insulating layer 12 and the substrate 11.

[0071] It should be noted that the material of the substrate 11 may be silicon or glass, etc. The material of the insulating layer 12 may be insulating materials such as silicon dioxide, N-type doped silicon or P-type doped silicon.

[0072] S120. Prepare a first temperature compensation unit and a first electrode of the transducer on a substrate, wherein the substrate includes a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and the absolute value of the temperature-elastic coefficient of the first temperature compensation unit is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer.

[0073] For example, Figure 3 A schematic diagram of a manufacturing process of a first temperature compensation unit and a first electrode of a transducer provided in an embodiment of the present invention, with reference to Figure 3 Step S120 is specifically as follows: first, a substrate 20 is provided, wherein the substrate 20 includes a base 21 and a piezoelectric layer 22 stacked along a first direction Z, wherein the piezoelectric layer 22 of the substrate 20 can be used as the piezoelectric layer 31 of the transducer 30; and then, a first temperature compensation unit 40 and a first electrode 32 of the transducer 30 are prepared on the piezoelectric layer 31 of the transducer 30.

[0074] Furthermore, the first temperature compensation unit 40 can be prepared by deposition, evaporation or sputtering. The entire first electrode layer can be prepared by deposition, evaporation or sputtering, and then the entire first electrode layer can be patterned to obtain the following: Figure 3 The first electrode 32 is shown.

[0075] It should be noted that the substrate 20 may be a POI substrate or a piezoelectric material with a damaged layer. Figure 3 When the substrate 20 is a POI substrate, the substrate 21 includes a high-resistance silicon substrate 211 and a silicon dioxide layer 212 stacked along a first direction Z, and the piezoelectric layer 22 includes single-crystal lithium tantalate or single-crystal lithium niobate. When the substrate 20 is a piezoelectric material with a damaged layer (not shown in the figure), the substrate 21 may include a damaged layer and a piezoelectric material located away from the piezoelectric layer 22 in the damaged layer, and the piezoelectric layer 22 may include a piezoelectric material located close to the piezoelectric layer 22 in the damaged layer, and the damaged layer refers to a damaged piezoelectric material, and the piezoelectric material may be single-crystal lithium tantalate or single-crystal lithium niobate. The embodiments of the present invention are described by taking the substrate 20 as an example of a POI substrate. A thin film bulk acoustic wave resonator prepared using single-crystal aluminum nitride or single-crystal lithium niobate can provide better power capacity, a larger mechanical quality factor, and a larger electromechanical coupling coefficient, thereby preparing a thin film bulk acoustic wave filter with better performance.

[0076] It is understandable that the resonant frequency of the thin film bulk acoustic wave resonator will drift due to changes in the external ambient temperature. This frequency drift is mainly attributed to the difference in the temperature-elastic coefficient between the material of the piezoelectric layer 31 and the materials of other layers, as well as the influence of temperature on the piezoelectric effect of the piezoelectric layer 31. It should be noted that the temperature-elastic coefficient refers to the amplitude of the change of the elastic stiffness coefficient (or mechanical parameters such as Young's modulus) of the material with temperature, and the change of this parameter can be positively correlated or negatively correlated with the temperature change. In the embodiment of the present invention, by setting the absolute value of the temperature-elastic coefficient of the first temperature compensation unit 40 to be smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer, that is, the elasticity of the first temperature compensation unit 40 is less affected by temperature, and the elasticity of the piezoelectric layer 31 is more affected by temperature, the first temperature compensation unit 40 can compensate for the temperature-elastic coefficient of the piezoelectric layer 31 in the thin film bulk acoustic wave resonator through its own elastic changes, which is conducive to reducing the influence of temperature on the performance of the thin film bulk acoustic wave resonator. For example, by combining a material with a negative temperature coefficient with a small absolute value (such as N-type doped single crystal silicon) or a material with a positive temperature coefficient (such as silicon dioxide) with a piezoelectric material with a negative temperature coefficient with a large absolute value (such as single crystal aluminum nitride or single crystal lithium niobate), the frequency-temperature coefficient of the thin film bulk acoustic wave resonator can be close to zero by precisely designing the thickness and order of each layer.

[0077] S130 , bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer.

[0078] For example, Figure 4 A schematic diagram of a bonding process between a first temperature compensation unit and an insulating layer provided in an embodiment of the present invention, referring to Figure 4 Step S130 specifically includes: firstly flipping the substrate 20 by 180° so that the first temperature compensation unit 40 faces the insulating layer 12 ; and then bonding the first temperature compensation unit 40 and the insulating layer 12 .

[0079] Further, as a feasible implementation, a polymer adhesive may be used to bond the first temperature compensation unit 40 and the insulating layer 12 together to achieve bonding between the first temperature compensation unit 40 and the insulating layer 12. It should be noted that in the embodiment of the present invention, the material of the first temperature compensation unit 40 and the material of the insulating layer 12 may be the same or different.

[0080] As another feasible implementation, the material of the temperature compensation unit 40 can be set to be the same as the material of the insulating layer 12. Both materials can be made of silicon dioxide, and the bonding method of direct bonding (i.e., forming a covalent bond) of silicon dioxide and silicon dioxide can be used to achieve the bonding of the first temperature compensation unit 40 and the insulating layer 12. Compared with the technical solution of setting the material of the temperature compensation unit 40 to be different from the material of the insulating layer 12, the embodiment of the present invention is conducive to improving the stability and strength of the bonding between the first temperature compensation unit 40 and the insulating layer 12 by setting the material of the temperature compensation unit 40 to be the same as the material of the insulating layer 12, and there is no need to set an adhesive between the two.

[0081] S140, removing the substrate.

[0082] For example, Figure 5 A schematic diagram of a preparation process for removing a substrate provided in an embodiment of the present invention, referring to Figure 5 , step S140 is specifically as follows: the substrate 21 may be removed by debonding, mechanical removal or chemical etching. Further, if the substrate 20 is a piezoelectric material with a damaged layer, the substrate 21 may be peeled off along the damaged layer, and then the surface of the peeled piezoelectric material may be subjected to chemical mechanical polishing (CMP) to remove the remaining damaged layer and planarize the piezoelectric material, thereby retaining only the undamaged piezoelectric material (the piezoelectric layer 22 of the substrate 20) as the piezoelectric layer 31 of the transducer 30.

[0083] S150, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0084] For example, Figure 6 A schematic diagram of a manufacturing process of a second electrode of a transducer provided in an embodiment of the present invention, referring to Figure 6 Step S150 is specifically: preparing the second electrode 33 of the transducer 30 on the side of the piezoelectric layer 31 away from the first electrode 32. Specifically, the entire second electrode layer can be prepared by deposition, evaporation or sputtering, and then the entire second electrode layer is patterned to obtain Figure 6 The second electrode 33 is shown.

[0085] refer to Figure 6 It should be noted that, along the first direction Z, the first electrode 32 , the second electrode 33 and the cavity 13 overlap, and the area of ​​the first electrode 32 and the area of ​​the second electrode 33 are both smaller than the area of ​​the cavity 13 .

[0086] In the embodiment of the present invention, a first temperature compensation unit 40 is provided which is stacked with the piezoelectric layer 31. The first temperature compensation unit 40 can adjust the internal stress of the thin film bulk acoustic wave resonator, reduce the influence of temperature on the piezoelectric layer 31, and further reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator, which is beneficial to reducing the temperature drift coefficient (TCF) of the thin film bulk acoustic wave resonator and improving the stability of the thin film bulk acoustic wave resonator. The first temperature compensation unit 40 and the first electrode 32 of the transducer 30 are prepared on the substrate 20 including the piezoelectric layer 31 of the transducer 30, and the first temperature compensation unit 40 and the insulating layer 12 are bonded to realize the production of the temperature compensated thin film bulk acoustic wave resonator, which is beneficial to reducing the production difficulty and improving the qualified rate.

[0087] Figure 7 A flowchart of another method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Figure 7 The illustrated embodiment describes in detail how to prepare the first temperature compensation unit and the first electrode of the transducer on the substrate, and how to bond the first temperature compensation unit and the insulating layer, based on the above embodiments. Figure 8 A schematic diagram of another manufacturing process of a first temperature compensation unit and a first electrode of a transducer provided by an embodiment of the present invention. Figure 7 and Figure 8 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0088] S210, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0089] S220, preparing a first electrode on a side of the piezoelectric layer away from the substrate.

[0090] Exemplary, reference Figure 8 , step S220 is specifically: preparing a first electrode 32 on the side of the piezoelectric layer 31 away from the substrate 21. Specifically, a first electrode layer of the entire layer can be prepared on the side of the piezoelectric layer 31 away from the substrate 21 by a deposition, evaporation or sputtering process, and then the entire first electrode layer is patterned to obtain a first electrode layer of the piezoelectric layer 31. Figure 8 The first electrode 32 is shown.

[0091] S230 , preparing a first temperature compensation layer of a first temperature compensation unit on a side of the first electrode away from the piezoelectric layer and a side of the piezoelectric layer away from the substrate.

[0092] Exemplarily, the first temperature compensation unit 40 only includes the first temperature compensation layer 41. Figure 8, step S230 specifically includes: preparing a first temperature compensation layer 41 on the side of the first electrode 32 away from the piezoelectric layer 31 and the side of the piezoelectric layer 31 away from the substrate 21. Specifically, the first temperature compensation layer 41 can be prepared on the side of the first electrode 32 away from the piezoelectric layer 31 and the side of the piezoelectric layer 31 away from the substrate 21 by using a deposition, evaporation or sputtering process, and then the first temperature compensation layer 41 can be flattened. Figure 8 The first temperature compensation layer 41 is shown. It should be noted that the planarization process is optional, and the first temperature compensation layer 41 may not be planarized.

[0093] S240 , bonding the first temperature compensation layer and the insulating layer.

[0094] Exemplary, reference Figure 4 , step S240 specifically includes: firstly turning the substrate 20 by 180° so that the first temperature compensation layer 41 faces the insulating layer 12; and then bonding the first temperature compensation layer 41 and the insulating layer 12. The specific bonding method of the first temperature compensation layer 41 and the insulating layer 12 can refer to the above description, which will not be repeated here.

[0095] S250, removing the substrate.

[0096] S260, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0097] It can be understood that the absolute value of the temperature-elastic coefficient of the temperature compensation layer is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer 31. The temperature compensation layer can compensate for the temperature-elastic coefficient of the piezoelectric layer 31 in the thin film bulk acoustic wave resonator through its own elastic change, which can reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator, but at the same time it will also suppress the electromechanical coupling coefficient of the thin film bulk acoustic wave resonator, wherein the larger the contact area between the temperature compensation layer and the piezoelectric layer 31, the greater the suppression of the electromechanical coupling coefficient by the temperature compensation layer. The first temperature compensation unit 40 (i.e., the first temperature compensation layer 41) in the temperature-compensated thin film bulk acoustic wave resonator prepared by steps S210-S260 is located on the side of the first electrode 32 away from the piezoelectric layer 31 and the side of the piezoelectric layer 31 away from the substrate 21, which can not only reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator, but also will not cause too much suppression of the electromechanical coupling coefficient of the thin film bulk acoustic wave resonator due to the large contact area with the piezoelectric layer 31.

[0098] Fig. 9 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig. 9The illustrated embodiment describes in detail how to prepare the first temperature compensation unit and the first electrode of the transducer on the substrate, and how to bond the first temperature compensation unit and the insulating layer, based on the above embodiments. Fig.10 A schematic diagram of a manufacturing process of another first temperature compensation unit and a first electrode of a transducer provided by an embodiment of the present invention. Fig. 9 and Fig.10 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0099] S310, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0100] S320 , preparing a second temperature compensation layer of the first temperature compensation unit on a side of the piezoelectric layer away from the substrate.

[0101] Exemplarily, the first temperature compensation unit 40 only includes the second temperature compensation layer 42, referring to Fig.10 Step S320 is specifically: preparing a second temperature compensation layer 42 on the side of the piezoelectric layer 31 away from the substrate 21. Specifically, a deposition, evaporation or sputtering process can be used to prepare a second temperature compensation layer 42 on the side of the piezoelectric layer away from the substrate. Fig.10 A second temperature compensation layer 42 is shown.

[0102] S330, preparing a first electrode on a side of the second temperature compensation layer away from the piezoelectric layer.

[0103] Exemplary, reference Fig.10 , step S330 is specifically: preparing the first electrode 32 on the side of the second temperature compensation layer 42 away from the piezoelectric layer 31. Specifically, a first electrode layer of the entire layer can be prepared on the side of the second temperature compensation layer 42 away from the piezoelectric layer 31 by using a deposition, evaporation or sputtering process, and then the entire first electrode layer is patterned to obtain the following: Fig.10 The first electrode 32 is shown.

[0104] S340 , bonding the second temperature compensation layer and the insulation layer.

[0105] Exemplarily, step S340 is specifically as follows: firstly, the substrate 20 is flipped 180 degrees so that the second temperature compensation layer 42 faces the insulating layer 12; and then, the second temperature compensation layer 42 and the insulating layer 12 are bonded. The specific bonding method of the second temperature compensation layer 42 and the insulating layer 12 can be referred to the above description, which is not repeated here.

[0106] S350, removing the substrate.

[0107] S360, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0108] It can be understood that the absolute value of the temperature-elastic coefficient of the temperature compensation layer is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer 31. The temperature compensation layer can compensate for the temperature-elastic coefficient of the piezoelectric layer 31 in the thin film bulk acoustic wave resonator through its own elastic change, which can reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator. The larger the contact area between the temperature compensation layer and the piezoelectric layer 31, the better the temperature compensation effect of the temperature compensation layer. The first temperature compensation unit 40 (i.e., the second temperature compensation layer 42) in the temperature-compensated thin film bulk acoustic wave resonator prepared by steps S310-S360 is located between the piezoelectric layer 31 and the first electrode 32 and between the piezoelectric layer 31 and the insulating layer 12. Compared with the technical solution of setting the first temperature compensation layer 41 (the first temperature compensation unit 40) to be located on the side of the first electrode 32 away from the piezoelectric layer 31 and between the piezoelectric layer 31 and the insulating layer 12, the contact area between the temperature compensation layer and the piezoelectric layer 31 in the embodiment of the present invention is larger, which is more conducive to reducing the influence of temperature on the performance of the thin film bulk acoustic wave resonator.

[0109] It should be noted that, in other feasible embodiments, the first temperature compensation unit 40 may include a first temperature compensation layer 41 and a second temperature compensation layer 42, the second temperature compensation layer 42 is located between the piezoelectric layer 31 and the first electrode 32 and between the piezoelectric layer 31 and the first temperature compensation layer 41, the first temperature compensation layer 41 is located on the side of the first electrode 32 away from the piezoelectric layer 31 and between the second temperature compensation layer 42 and the insulating layer 12, in which case the bonding of the first temperature compensation unit 40 and the insulating layer 12 is achieved by bonding the second temperature compensation layer 42 and the insulating layer 12. The specific preparation method of the first temperature compensation layer 41 and the second temperature compensation layer 42 can refer to the above.

[0110] Fig.11 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig.11 The illustrated embodiment enriches the process of the method for manufacturing a temperature-compensated thin-film bulk acoustic wave resonator based on the above-mentioned embodiment, and provides a detailed description of how to prepare the first electrode on the side of the second temperature compensation layer away from the piezoelectric layer, and how to bond the second temperature compensation layer and the insulating layer. Fig.12 A schematic diagram of a manufacturing process of another first temperature compensation unit and a first electrode of a transducer provided by an embodiment of the present invention. Fig.11 and Fig.12 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0111] S410, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0112] S420 , preparing a second temperature compensation layer of the first temperature compensation unit on a side of the piezoelectric layer away from the substrate.

[0113] S430, patterning the second temperature compensation layer to obtain a bonding temperature compensation section and an electrode temperature compensation section that are isolated from each other, wherein the electrode temperature compensation section, the active area of ​​the transducer and the cavity overlap in a first direction, and the area of ​​the electrode temperature compensation section is larger than the area of ​​the active area and smaller than the area of ​​the cavity.

[0114] It should be noted that the first direction Z is the thickness direction of the temperature-compensated thin film bulk acoustic wave resonator. The active region is the region along the first direction Z where the first electrode 32 and the second electrode 33 overlap.

[0115] Exemplary, reference Fig.12 Step S430 specifically includes: patterning the second temperature compensation layer 42 to obtain a bonding temperature compensation sub-portion 421 and an electrode temperature compensation sub-portion 422 that are isolated from each other.

[0116] S440, preparing a first electrode on a side of the electrode temperature compensation portion away from the piezoelectric layer.

[0117] Exemplary, reference Fig.12 , step S430 is specifically: preparing the first electrode 32 on the side of the electrode temperature compensation sub-part 422 away from the piezoelectric layer 31. Specifically, a deposition, evaporation or sputtering process can be used to prepare a whole first electrode layer on the side of the electrode temperature compensation sub-part 422 away from the piezoelectric layer 31, and then the whole first electrode layer is patterned to obtain the following: Fig.12 The first electrode 32 is shown.

[0118] S450, bonding the temperature compensation section and the insulating layer.

[0119] Exemplarily, step S450 is specifically as follows: first, the substrate 20 is flipped 180° so that the bonding temperature compensation section 421 faces the insulating layer 12; and then the bonding temperature compensation section 421 and the insulating layer 12 are bonded. The specific bonding method of the bonding temperature compensation section 421 and the insulating layer 12 can be referred to the above description, which will not be repeated here. It should be noted that the bonding temperature compensation section 421 and the insulating layer 12 overlap in the first direction Z, and the area of ​​the bonding temperature compensation section 421 is substantially the same as the area of ​​the insulating layer 12.

[0120] S460, removing the base.

[0121] S470, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0122] The embodiment of the present invention patterns the prepared second temperature compensation layer 42 to divide it into a mutually isolated bonding temperature compensation section and an electrode temperature compensation section, thereby preventing the bonding between the bonding temperature compensation section and the insulating layer from affecting the properties of the electrode temperature compensation section, thereby affecting the temperature compensation effect of the electrode temperature compensation section.

[0123] Fig.13 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig.13 The illustrated embodiment enriches the process of the method for manufacturing a temperature-compensated thin film bulk acoustic resonator on the basis of the above-mentioned embodiment, and describes in detail how to prepare the second electrode of the transducer on the side of the piezoelectric layer away from the first electrode. Fig.14 A schematic diagram of a manufacturing process of a third temperature compensation layer of a second temperature compensation unit provided by an embodiment of the present invention. Fig.13 and Fig.14 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0124] S510, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0125] S520. Prepare a first temperature compensation unit and a first electrode of the transducer on a substrate, wherein the substrate includes a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and the absolute value of the temperature-elastic coefficient of the first temperature compensation unit is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer.

[0126] S530 , bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer.

[0127] S540, removing the substrate.

[0128] S550 , preparing a third temperature compensation layer of a second temperature compensation unit on a side of the piezoelectric layer away from the first electrode.

[0129] Exemplarily, the second temperature compensation unit 50 includes a third temperature compensation layer 51, referring to Fig.14 Step S550 specifically includes: preparing a third temperature compensation layer 51 on a side of the piezoelectric layer 31 away from the first electrode 32. Specifically, the third temperature compensation layer 51 may be prepared by a deposition, evaporation or sputtering process.

[0130] S560, preparing a second electrode on a side of the third temperature compensation layer away from the piezoelectric layer.

[0131] Exemplary, reference Fig.14Step S560 is specifically: preparing the second electrode 33 of the transducer 30 on the side of the third temperature compensation layer 51 away from the piezoelectric layer 31. Specifically, the entire second electrode layer can be prepared by deposition, evaporation or sputtering, and then the entire second electrode layer is patterned to obtain Fig.14 The second electrode 33 .

[0132] The embodiment of the present invention can further increase the contact area between the temperature compensation layer and the piezoelectric layer 31 by setting a third temperature compensation layer 51 between the piezoelectric layer 31 and the second electrode 33, further reduce the influence of temperature on the performance of the thin film bulk acoustic wave resonator, and help to further reduce the temperature drift coefficient (TCF) of the thin film bulk acoustic wave resonator, and further improve the stability of the thin film bulk acoustic wave resonator.

[0133] Fig.15 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig.15 The illustrated embodiment enriches the process of the method for manufacturing a temperature-compensated thin film bulk acoustic resonator on the basis of the above-mentioned embodiment. Fig.16 A schematic diagram of a process for preparing a passivation layer provided in an embodiment of the present invention, referring to Fig.15 and Fig.16 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0134] S610, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0135] S620. Prepare a first temperature compensation unit and a first electrode of the transducer on a substrate, wherein the substrate includes a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and the absolute value of the temperature-elastic coefficient of the first temperature compensation unit is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer.

[0136] S630 , bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer.

[0137] S640, removing the substrate.

[0138] S650, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0139] S660, preparing a passivation layer on a side of the transducer away from the support structure.

[0140] Exemplary, reference Fig.16, step S660 is specifically as follows: a passivation layer 60 is prepared on the side of the transducer 30 away from the support structure 10. Specifically, a passivation layer 60 is deposited, evaporated or sputtered on the exposed surface of the second electrode 33 and the surface of the upper surface of the piezoelectric layer 31 where the second electrode 33 is not provided. The passivation layer 60 can protect the temperature-compensated thin film bulk acoustic wave resonator from corrosion and contamination, which is beneficial to improving the stability and reliability of the temperature-compensated thin film bulk acoustic wave resonator.

[0141] It should be noted that the passivation layer 60 may be made of materials such as aluminum nitride, aluminum oxide or silicon dioxide.

[0142] Fig.17 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig.17 The illustrated embodiment enriches the process of the method for manufacturing a temperature-compensated thin film bulk acoustic resonator on the basis of the above-mentioned embodiment, and describes in detail how to prepare the second electrode of the transducer on the side of the piezoelectric layer away from the first electrode. Fig.18 A schematic diagram of a manufacturing process of a heat dissipation structure provided by an embodiment of the present invention. Fig.17 and Fig.18 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0143] S710, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0144] S720. Prepare a first temperature compensation unit and a first electrode of the transducer on a substrate, wherein the substrate includes a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and the absolute value of the temperature-elastic coefficient of the first temperature compensation unit is smaller than the absolute value of the temperature-elastic coefficient of the piezoelectric layer.

[0145] S730 , bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer.

[0146] S740, removing the substrate.

[0147] S750, preparing a second electrode of the transducer on a side of the piezoelectric layer away from the first electrode.

[0148] S760, preparing a passivation layer on a side of the transducer away from the support structure.

[0149] S770, preparing a heat dissipation structure on a side of the passivation layer away from the transducer, wherein the heat dissipation structure does not overlap with an active area of ​​the transducer in a first direction.

[0150] It should be noted that the first direction Z is the thickness direction of the temperature-compensated thin film bulk acoustic wave resonator. The active region is the region along the first direction Z where the first electrode 32 and the second electrode 33 overlap.

[0151] As a feasible implementation method, refer to Fig.18 , preparing a heat dissipation structure 70 on the side of the passivation layer 60 away from the transducer 30, including: preparing a heat dissipation layer 71 on the side of the passivation layer 60 away from the transducer 70; etching the heat dissipation layer 71 to form protrusions 72 and grooves 73 alternately arranged along the second direction X and / or the third direction Y. The first direction, the second direction and the third direction intersect each other.

[0152] Exemplarily, the heat dissipation material used to make the heat dissipation structure 70 may be a metal or non-metal with high thermal conductivity, such as gold, copper, SiC, diamond, etc.

[0153] The embodiment of the present invention can dissipate the heat generated by the temperature-compensated thin film bulk acoustic wave resonator by providing a heat dissipation structure 70, which is beneficial to improving the heat dissipation performance of the temperature-compensated thin film bulk acoustic wave resonator and increasing the power capacity. By providing the heat dissipation structure 70 including the protrusions 72 and the grooves 73 arranged alternately, the heat dissipation area of ​​the heat dissipation structure 70 can be increased, the heat dissipation performance of the temperature-compensated thin film bulk acoustic wave resonator can be further improved, and the power capacity can be further increased.

[0154] Fig.19 A flow chart of a method for manufacturing a temperature-compensated thin film bulk acoustic resonator provided by an embodiment of the present invention, Fig.19 The embodiment shown in the figure describes in detail how to prepare the first temperature compensation unit and the first electrode of the transducer on the substrate based on the above embodiment, and how to prepare the second electrode of the transducer on the side of the piezoelectric layer away from the first electrode. Fig.19 The method for manufacturing a temperature-compensated thin film bulk acoustic resonator in an embodiment of the present invention includes:

[0155] S810, preparing a support structure, wherein the support structure includes a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate.

[0156] S820, preparing a first temperature compensation unit and a first interdigital electrode of an interdigital transducer on a substrate.

[0157] Exemplarily, the first interdigitated electrode is the first electrode 32 mentioned in the above embodiment, and only differs in structure. Specifically, the first electrode 32 in the embodiment of the present invention is an interdigitated type including a plurality of alternately arranged electrode fingers, while the first electrode 32 in the above embodiment is a whole electrolyte sheet. Therefore, the specific implementation of step S820 can be referred to above, and will not be described in detail here.

[0158] S830 , bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer.

[0159] S840, removing the substrate.

[0160] S850, preparing a second interdigital electrode of the interdigital transducer on a side of the piezoelectric layer away from the first electrode.

[0161] Exemplarily, the second interdigitated electrode is the second electrode 33 mentioned in the above embodiment, and only differs in structure. Specifically, the second electrode 33 in the embodiment of the present invention is an interdigitated type including a plurality of alternately arranged electrode fingers, while the second electrode 33 in the above embodiment is a whole electrolyte sheet. Therefore, the specific implementation of step S850 can be referred to above, and will not be described in detail here.

[0162] Fig. 20 FIG. 1 is a schematic diagram of a temperature-compensated Lamb wave resonator provided in an embodiment of the present invention. The temperature-compensated thin film bulk acoustic wave resonator obtained after executing steps S180-S850 is as follows: Fig. 20 The temperature compensated Lamb wave resonator shown. It should be noted that, along the first direction Z, the electrode fingers located in the same vertical plane can have the same or opposite electrical properties, and can excite antisymmetric Lamb waves when they have the same electrical properties, and can excite symmetric Lamb waves when they have opposite electrical properties.

[0163] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a temperature-compensated thin film bulk acoustic resonator, characterized in that: The production method comprises: Preparing a support structure; wherein the support structure comprises a stacked substrate and an insulating layer, and a cavity penetrating the insulating layer and at least a portion of the substrate; A first temperature compensation unit and a first electrode of a transducer are prepared on a substrate; wherein the substrate comprises a laminated base and a piezoelectric layer of the transducer, the piezoelectric layer, the first electrode and the first temperature compensation unit are laminated, and an absolute value of a temperature-elastic coefficient of the first temperature compensation unit is smaller than an absolute value of a temperature-elastic coefficient of the piezoelectric layer; bonding the first temperature compensation unit and the insulating layer in a manner that the first temperature compensation unit faces one side of the insulating layer; removing the substrate; A second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode.

2. The method according to claim 1, characterized in that: A first temperature compensation unit and a first electrode of a transducer are prepared on a substrate, comprising: Prepare the first electrode on a side of the piezoelectric layer away from the substrate; Preparing a first temperature compensation layer of the first temperature compensation unit on a side of the first electrode away from the piezoelectric layer and a side of the piezoelectric layer away from the substrate; Bonding the first temperature compensation unit and the insulating layer, comprising: The first temperature compensation layer and the insulating layer are bonded.

3. The method according to claim 1, characterized in that: A first temperature compensation unit and a first electrode of a transducer are prepared on a substrate, comprising: Prepare a second temperature compensation layer of the first temperature compensation unit on a side of the piezoelectric layer away from the substrate; preparing the first electrode on a side of the second temperature compensation layer away from the piezoelectric layer; Bonding the first temperature compensation unit and the insulating layer, comprising: The second temperature compensation layer and the insulating layer are bonded.

4. The method according to claim 3, characterized in that: After preparing the second temperature compensation layer of the first temperature compensation unit on the side of the piezoelectric layer away from the substrate, the manufacturing method further includes: The second temperature compensation layer is patterned to obtain a bonding temperature compensation subsection and an electrode temperature compensation subsection that are isolated from each other; wherein the electrode temperature compensation subsection, the active area of ​​the transducer and the cavity overlap in a first direction, and the area of ​​the electrode temperature compensation subsection is larger than the area of ​​the active area and smaller than the area of ​​the cavity; the first direction is the thickness direction of the temperature-compensated thin film bulk acoustic resonator; the active area is the area where the first electrode overlaps with the second electrode along the first direction; The first electrode is prepared on a side of the second temperature compensation layer away from the piezoelectric layer, comprising: Prepare the first electrode on a side of the electrode temperature compensation section away from the piezoelectric layer; Bonding the second temperature compensation layer and the insulating layer, comprising: The bonding temperature compensation section and the insulating layer are bonded.

5. The method according to claim 1, characterized in that: After removing the substrate, the manufacturing method further comprises: Prepare a third temperature compensation layer of a second temperature compensation unit on a side of the piezoelectric layer away from the first electrode; The second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode, comprising: The second electrode is prepared on a side of the third temperature compensation layer away from the piezoelectric layer.

6. The method according to claim 1, characterized in that: The production method further comprises: A passivation layer is prepared on a side of the transducer away from the support structure.

7. The manufacturing method according to claim 6, characterized in that: The production method further comprises: A heat dissipation structure is prepared on a side of the passivation layer away from the transducer; wherein the heat dissipation structure and the active area of ​​the transducer do not overlap in a first direction; the first direction is the thickness direction of the temperature-compensated thin film bulk acoustic resonator; and the active area is the area where the first electrode and the second electrode overlap along the first direction.

8. The method according to claim 7, characterized in that: A heat dissipation structure is prepared on a side of the passivation layer away from the transducer, comprising: Preparing a heat dissipation layer on a side of the passivation layer away from the transducer; The heat dissipation layer is etched to form protrusions and grooves alternately arranged along the second direction and / or the third direction; wherein the first direction, the second direction and the third direction intersect each other.

9. The manufacturing method according to claim 1, characterized in that: A first temperature compensation unit and a first electrode of a transducer are prepared on a substrate, comprising: Preparing a first temperature compensation unit and a first interdigital electrode of an interdigital transducer on the substrate; The second electrode of the transducer is prepared on a side of the piezoelectric layer away from the first electrode, comprising: A second interdigital electrode of the interdigital transducer is prepared on a side of the piezoelectric layer away from the first electrode.

10. The manufacturing method according to claim 1, characterized in that: The material of the temperature compensation unit is the same as that of the insulation layer.

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