JP2009290364A - Baw resonance device, and manufacturing method thereof - Google Patents

Abstract

A BAW resonance device that can be robust without increasing parasitic capacitance and a method for manufacturing the same.
A BAW resonance device according to the present embodiment reinforces peripheral portions of etching holes 5 and 5 in an insulating layer 4 and reinforces 6 and 6 made of a metal material that is electrically insulated from a resonator 3. Are formed two by two. The reinforcing portions 6 are formed on both surfaces in the thickness direction of the insulating layer 4 with respect to the respective etching holes 5. The reinforcing portions 6 formed on the insulating substrate 4 on the support substrate 1 side are the same as the lower electrode 31. The reinforcing portion 6 formed to the same thickness as the lower electrode 31 by the metal material and formed on the opposite side of the support layer 1 in the insulating layer 4 is the same as the upper electrode 33 by the same metal material as the upper electrode 33. It is formed to a thickness.
[Selection] Figure 1

Description

  The present invention relates to a BAW (Bulk Acoustic Wave) resonance device including a resonator using a longitudinal vibration mode in a thickness direction of a piezoelectric layer, and a manufacturing method thereof.

Conventionally, as a BAW resonance device applicable to a high frequency filter used in a high frequency band of 2 GHz or more in the field of mobile communication devices such as mobile phones, for example, as shown in FIG. A resonator 3 ′ formed on one surface side of the substrate 1 ′ and having a laminated structure of a lower electrode 31 ′, a piezoelectric layer 32 ′, and an upper electrode 33 ′, and a support substrate formed on the one surface side of the support substrate 1 ′. And an insulating layer 4 ′ that surrounds the entire circumference of the resonator 3 ′ and holds the resonator 3 ′ in a plan view, and is disposed on the one surface of the support substrate 1 ′ below the resonator 3 ′. A recess 2 'is formed to expose the surface of the support layer 7' and the insulating layer 4 'on the support substrate 1' side so that the piezoelectric layer 32 'can be physically vibrated. In the periphery of the resonator 3 ', an etching hole for forming a recess communicating with the recess 2'. Le 5 ', 5' FBAR that is formed (Film Bulk Acoustic Resonator) type BAW resonator device has been proposed (e.g., see Patent Document 1). Here, the insulating layer 4 ', the first protective layer 41 made of SiO ₂ film' second protective layer of SiO ₂ film formed on the side opposite to the side 'supporting substrate 1' in the first protective layer 41 42 '. Note that the thickness of the first protective layer 41 ′ is set to 0.4 μm, and the thickness of the second protective layer 42 ′ is set to 0.2 μm.

  Note that Patent Document 1 also describes that a filter (BAW filter) is formed by forming a plurality of resonators on the one surface side of the support substrate.

By the way, in the above-mentioned BAW resonance device, AlN or the like is adopted as the piezoelectric material of the piezoelectric layer 32 ', and Si, GaAs, glass or the like is adopted as the material of the support substrate 1', but for UWB (Ultra Wide Band). When applied to a filter, the piezoelectric material of the piezoelectric layer 32 ′ can obtain a bandwidth of about 10% with respect to the center frequency as compared with AlN whose bandwidth is only 4 to 5% with respect to the center frequency. Possible lead-based piezoelectric materials (for example, PZT, PMN-PZT, etc.) are employed, and MgO or SrTiO ₃ may be employed as the material of the support substrate 1 ′ in order to improve the crystallinity of the piezoelectric layer 32 ′. (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 10-126160 (paragraphs [0026]-[0032], [0068], [0079] and FIG. 2) JP-A-10-261934 (paragraphs [0023]-[0027] and FIGS. 1 and 2)

  However, in the BAW resonator having the configuration shown in FIG. 7, since the etching holes 5 and 5 are formed in the insulating layer 4 ′, there is a problem that the peripheral portion of the etching hole in the insulating layer 4 ′ becomes fragile. there were.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a BAW resonance device that can be robust without increasing parasitic capacitance, and a method for manufacturing the same.

  The invention according to claim 1 is a support substrate, a resonator formed on one surface side of the support substrate and having a laminated structure of a lower electrode, a piezoelectric layer, and an upper electrode, and a support substrate formed on the one surface side of the support substrate. And an insulating layer that surrounds the entire circumference of the resonator in a plan view and holds the resonator, and the surface of the lower electrode of the resonator and the surface on the side of the supporting substrate of the insulating layer are formed on the one surface of the supporting substrate. A recess to be exposed is formed, and an etching hole for forming a recess communicating with the recess is formed in a peripheral portion of the resonator in the insulating layer, and the peripheral portion of the etching hole in the insulating layer is reinforced and the resonator A reinforcing portion made of a metal material electrically insulated from each other is formed on an insulating layer.

  According to this invention, since the recess that exposes the lower electrode of the resonator and the surface on the support substrate side in the insulating layer is formed on one surface of the support substrate, energy loss of the bulk acoustic wave can be reduced, The mechanical quality factor of the entire resonator can be improved, and the reinforcing portion made of a metal material that reinforces the periphery of the etching hole in the insulating layer and is electrically insulated from the resonator is formed in the insulating layer. The robustness can be achieved without increasing the parasitic capacitance.

The invention of claim 2 is characterized in that, in the invention of claim 1, the support substrate is made of MgO or SrTiO ₃ , and the piezoelectric layer is made of a lead-based piezoelectric material.

According to this invention, since the piezoelectric layer is formed of a lead-based piezoelectric material, an electromechanical coupling coefficient can be increased as compared with the case where the piezoelectric layer is formed of AlN, and the support substrate is Since it is made of MgO or SrTiO _3, the crystallinity of the piezoelectric layer can be improved compared to the case where the support substrate is made of Si, GaAs, glass, etc. It is possible to improve the quality factor.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the reinforcing portion is made of the same metal material as the lower electrode and is formed on the support substrate side in the insulating layer. And

  According to the present invention, a manufacturing process in which the reinforcing portion is formed simultaneously with the lower electrode can be adopted, and the manufacturing process can be simplified and the cost can be reduced.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the reinforcing portion is made of the same metal material as the upper electrode, and is formed on the opposite side of the insulating layer from the support substrate side. It is characterized by becoming.

  According to this invention, a manufacturing process in which the reinforcing portion is formed simultaneously with the upper electrode can be adopted, and the manufacturing process can be simplified and the cost can be reduced.

  According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the reinforcing portion is formed on both surfaces of the insulating layer in the thickness direction, and the insulating layer is formed on the support substrate side. The reinforcing portion is made of the same metal material as the lower electrode, and the reinforcing portion formed on the opposite side of the insulating layer from the support substrate side is made of the same metal material as the upper electrode. To do.

  According to this invention, since the reinforcing portion is formed on both surfaces in the thickness direction of the insulating layer, it is possible to achieve further robustness compared to the inventions of claims 3 and 4, and in the insulating layer. The reinforcing portion formed on the support substrate side is made of the same metal material as the lower electrode, and the reinforcing portion formed on the opposite side of the insulating layer from the support substrate side is the same as the upper electrode. Therefore, it is possible to employ a manufacturing process in which the reinforcing portion on the support substrate side in the insulating layer is formed simultaneously with the lower electrode, and on the opposite side of the insulating layer from the support substrate side. A manufacturing process in which the reinforcing portion is formed simultaneously with the upper electrode can be employed, and the manufacturing process can be simplified and the cost can be reduced.

  According to a sixth aspect of the invention, in the first to fifth aspects of the invention, the metal material of each of the lower electrode and the upper electrode is at least one selected from the group consisting of Pt, Mo, W, Ir, Cr, and Ru. It is a seed.

  According to this invention, since the metal material of each of the lower electrode and the upper electrode is at least one selected from the group of Pt, Mo, W, Ir, Cr, Ru, the lower electrode and the upper electrode The mechanical quality factor of each of the lower electrode and the upper electrode can be increased compared to the case of Al or Au, which is a representative electrode material of each metal material, and the mechanical quality factor of the entire resonator can be increased. It becomes possible to raise.

  A seventh aspect of the invention is a method for manufacturing a BAW resonance device according to any one of the first to sixth aspects, wherein the reinforcing portion is formed on the one surface side of the support substrate. An etching hole forming step for forming an etching hole in the insulating layer after the reinforcing portion forming step, and a recess forming step for forming a recess in the one surface of the support substrate through the etching hole after the etching hole forming step. It is characterized by providing.

  According to the present invention, it is possible to provide a BAW resonance device that can improve the mechanical quality factor of the entire resonator and can be robust without increasing the parasitic capacitance.

  According to the first aspect of the present invention, the Q value of the entire resonator can be improved, and robustness can be achieved without increasing the parasitic capacitance.

  According to the invention of claim 7, there is an effect that it is possible to provide a BAW resonance device that can improve the Q value of the entire resonator and can be robust without increasing the parasitic capacitance.

(Embodiment 1)
As shown in FIG. 1, the BAW resonator of this embodiment includes a support substrate 1 and a resonator 3 having a laminated structure of a lower electrode 31, a piezoelectric layer 32, and an upper electrode 33 formed on one surface side of the support substrate 1. And an insulating layer 4 formed on the one surface side of the support substrate 1 and supported by the support substrate 1 so as to surround the resonator 3 over the entire circumference in a plan view and hold the resonator 3. A recess 2 exposing the surface of the resonator 3 and the insulating layer 4 on the side of the support substrate 1 is formed on the one surface, and the periphery of the resonator 3 in the insulating layer 4 communicates with the recess 2. A plurality (two in this embodiment) of etching holes 5 and 5 for forming the recesses are formed. In short, the BAW resonator of this embodiment suppresses the propagation of energy of bulk acoustic waves to the support substrate 1 side by increasing the acoustic impedance ratio between the lower electrode 31 and the medium immediately below the lower electrode 31. FBAR is configured.

  In the resonator 3 described above, the lower electrode 31 is formed on the support substrate 1 side, the piezoelectric layer 32 is formed on the opposite side of the lower electrode 31 to the support substrate 1 side, and the piezoelectric layer 32 is opposite to the lower electrode 31 side. An upper electrode 33 is formed on the side.

  Further, in the BAW resonance device of the present embodiment, an opening 4 a that defines the contact area between the upper electrode 33 and the piezoelectric layer 32 is formed in the insulating layer 4 described above, and the lower electrode 31 of the piezoelectric layer 32 is formed. A region in contact with both the upper electrode 33 and the upper electrode 33 constitutes a resonance region.

The BAW resonator of the present embodiment employs PMN-PZT as the piezoelectric material of the piezoelectric layer 32, and supports the piezoelectric layer 32 so as to obtain a piezoelectric thin film composed of a (001) -oriented PMN-PZT thin film. As the substrate 1, a single crystal MgO substrate having a (001) plane as its main surface is used as the substrate 1. However, as the support substrate 1, a single crystal STO (with a (001) plane as its main surface is used as the support substrate 1. : SrTiO ₃ ) substrate may be used. The PMN-PZT thin film may be a single crystal film or a single orientation film, and the orientation is not limited to (001) orientation, and may be, for example, (111) orientation.

  Further, in the BAW resonance device of the present embodiment, Pt is adopted as the metal material of the lower electrode 31 and the upper electrode 33. However, these metal materials are not particularly limited. For example, Al or other metal materials are used. For example, if at least one selected from the group of Pt, Mo, W, Ir, Cr, Ru is employed, the metal material of each of the lower electrode 31 and the upper electrode 33 is a representative electrode material. As compared with the case of Au, the mechanical quality factor of each of the lower electrode 31 and the upper electrode 33 can be increased, and the mechanical quality factor of the entire resonator 3 can be increased. The lower electrode 31 and the upper electrode 33 are not necessarily made of the same metal material, and the metal material of the lower electrode 31 is a lattice with the piezoelectric material of the piezoelectric layer 32 in order to suppress lattice distortion of the piezoelectric layer 32. It is desirable to use a metal material having a small constant difference.

The piezoelectric layer 32 is formed of a piezoelectric thin film made of a (001) -oriented PMN-PZT thin film. Here, the composition of PMN-PZT is represented by the chemical formula x (Pb (Mn _1/3 Nb _2/3 ) O _3- (1-x) (PbZr _y Ti _1-y O ₃ ), and this embodiment In this embodiment, x = 0.10 and y = 0.52, but these values are only examples and are not particularly limited, and in this embodiment, the piezoelectric material of the piezoelectric layer 32 is a lead-based piezoelectric material. Since the material is adopted, the electromechanical coupling coefficient can be increased as compared with the case where the piezoelectric material is AlN or ZnO, and the piezoelectric material of the piezoelectric layer 32 is not limited to the lead-based piezoelectric material, For example, lead-free KNN (K _0.5 Na _0.5 NbO ₃ ), KN (KNbO ₃ ), NN (NaNbO ₃ ), and impurities (for example, Li, Nb, Ta, Sb, Cu, etc.) are added to KNN. It may be added.

As a material of the insulating layer 4, is adopted to SiO _2, is not limited to SiO _2, for example, it may be adopted _Si 3 _{N 4.} The insulating layer 4 is not limited to a single layer structure, and may be a multilayer structure, for example, a laminated film of a first insulating film made of SiO ₂ and a second insulating film made of Si ₃ N ₄ film.

  In the BAW resonator of this embodiment, the resonance frequency of the resonator 3 is set to 4 GHz, the thickness of the lower electrode 31 is set to 100 nm, the thickness of the piezoelectric layer 32 is set to 300 nm, and the thickness of the upper electrode 33 is set to 100 nm. However, these numerical values are examples and are not particularly limited. Moreover, when designing the resonance frequency in the range of 3 GHz to 5 GHz, the thickness of the piezoelectric layer 32 may be set as appropriate in the range of 200 nm to 600 nm.

  By the way, in the BAW resonance device of the present embodiment, the reinforcing portions 6 and 6 made of a metal material that reinforces the peripheral portions of the etching holes 5 and 5 in the insulating layer 4 and is electrically connected to the resonator 3 are two. It is formed one by one. Here, the reinforcing portions 6 are formed on both surfaces in the thickness direction of the insulating layer 4 with respect to the respective etching holes 5, and the reinforcing portions formed on the supporting substrate 1 side in the insulating layer 4 (hereinafter, described) (For convenience, it may be referred to as a first reinforcing portion) 6 is formed of the same metal material as that of the lower electrode 31 to have the same thickness as the lower electrode 31 and is formed on the side of the insulating layer 4 opposite to the support substrate 1 side. The formed reinforcing portion (hereinafter also referred to as a second reinforcing portion for convenience of explanation) 6 is formed of the same metal material as the upper electrode 33 and has the same thickness as the upper electrode 33. Here, the reinforcing portion 6 is formed from a peripheral portion of the etching hole 5 in the insulating layer 4 to a portion overlapping the peripheral portion of the recess 2 of the supporting substrate 1 in the insulating layer 4. The first reinforcing portion 6 is formed simultaneously with the lower electrode 31, the second reinforcing portion 6 is formed simultaneously with the upper electrode 33, and each reinforcing portion 6 includes the lower electrode 31 and the upper portion in the thickness direction. The pattern is designed so as not to overlap any of the electrodes 33.

  Hereinafter, a method for manufacturing the BAW resonator according to the present embodiment will be described with reference to FIGS.

  First, a first metal film (for example, a base of the lower electrode 31 and the first reinforcing portion 6 is formed on the entire surface of the one surface side of the support substrate 1 made of a single crystal MgO substrate having a (001) surface. A structure shown in FIG. 2A is obtained by performing a first metal film forming step of forming a Pt film or the like) 31a by sputtering, EB vapor deposition, CVD, or the like.

  After the first metal film forming step, a piezoelectric material layer 32a made of (001) -oriented PMN-PZT serving as the basis of the piezoelectric layer 32 is formed on the entire surface of the support substrate 1 on the one surface side by sputtering or CVD. The structure shown in FIG. 2B is obtained by performing a piezoelectric material layer forming process formed by the sol-gel method or the like. Note that a seed layer for controlling the orientation of the piezoelectric material layer 32a may be formed before the formation of the piezoelectric material layer 32a.

  After the above-described piezoelectric material layer forming step, a piezoelectric material layer patterning step is performed by patterning the piezoelectric material layer 32a into a desired planar shape using a photolithography technique and an etching technique, thereby forming a part of the piezoelectric material layer 32a. By performing the piezoelectric material layer patterning step for forming the piezoelectric layer 32, the structure shown in FIG. 2C is obtained.

  Subsequently, the first metal film 31a is patterned by using the photolithography technique and the etching technique, thereby forming the lower electrode 31 and the first reinforcing portions 6 and 6 each of which is a part of the first metal film 31a. By performing the first metal film patterning step, the structure shown in FIG. 2D is obtained.

Thereafter, an insulating layer forming step of forming an insulating layer 4 made of, for example, SiO ₂ on the entire surface of the one surface of the support substrate 1 by a sputtering method, a CVD method, or the like is performed, and subsequently, using a photolithography technique and an etching technique. The structure shown in FIG. 3A is obtained by performing an insulating layer patterning step for forming the opening 4a in the insulating layer 4.

  Thereafter, the upper electrode 33 and the second metal film (for example, Pt film) serving as the basis of the second reinforcing portion 6 are formed on the entire surface of the support substrate 1 on the one surface side by sputtering, EB vapor deposition, CVD, or the like. A second metal film forming step formed by the above is performed, and then the second metal film is patterned by using a photolithography technique and an etching technique, so that each upper electrode 33 made of a part of the second metal film is formed. And the structure shown in FIG.3 (b) is obtained by performing the 2nd metal film patterning process which forms the 2nd reinforcement parts 6 and 6. FIG. In the present embodiment, the first metal film forming step, the first metal film patterning step, the second metal film forming step, and the second metal film patterning step are arranged on the one surface side of the support substrate 1. The reinforcement part formation process which forms the 1 reinforcement part 6 and the 2nd reinforcement part 6 is comprised.

  After the above-described reinforcing portion forming step, an etching hole forming step for forming the etching holes 5 and 5 in the insulating layer 4 is performed, thereby obtaining the structure shown in FIG.

  Thereafter, a part of the support substrate 1 is etched through the etching holes 5 and 5 to perform a recess forming step for forming the recess 2 on the one surface of the support substrate 1, whereby the structure shown in FIG. The BAW resonance device is obtained. When the MgO substrate is used as the support substrate 1 as described above, phosphoric acid that can be anisotropically etched may be used as the etchant.

  In manufacturing the above-described BAW resonance device, a large number of BAW resonance devices may be formed at the wafer level using a wafer as the above-described support substrate 1 and then divided into individual BAW resonance devices in a dicing process.

  In the BAW resonator of the present embodiment described above, the recess 2 that exposes the lower electrode 31 of the resonator 3 and the surface of the insulating layer 4 on the support substrate 1 side is formed on the one surface of the support substrate 1. Therefore, as compared with the case where the support layer 7 ′ is formed under the lower electrode 31 ′ as in the conventional configuration shown in FIG. 7, the energy loss of the bulk acoustic wave can be reduced, and the mechanical properties of the entire resonator 3 can be reduced. The quality factor can be improved, and the first reinforcing portions 6, 6 made of a metal material that reinforces the peripheral portions of the etching holes 5, 5 in the insulating layer 4 and is electrically insulated from the resonator 3, Since the reinforcing portions 6 and 6 are formed in the insulating layer 4, it is possible to achieve robustness without increasing the parasitic capacitance.

  In addition, according to the above-described method for manufacturing a BAW resonance device, the reinforcing portion forming step of forming the reinforcing portions 6, 6, 6, 6 on the one surface side of the support substrate 1, and the insulating layer after the reinforcing portion forming step 4 includes an etching hole forming process for forming etching holes 5 and 5, and a recess forming process for forming the recess 2 on the one surface of the support substrate 1 through the etching holes 5 and 5 after the etching hole forming process. Therefore, it is possible to provide a BAW resonance device that can improve the mechanical quality factor of the entire resonator 3 and can be robust without increasing parasitic capacitance.

  In the BAW resonance device of this embodiment, the first reinforcing portion 6 formed on the insulating substrate 4 on the support substrate 1 side is made of the same metal material as the lower electrode 31, and the insulating layer 4 on the support substrate 1 side. Since the second reinforcing portion 6 formed on the opposite side to the upper electrode 33 is made of the same metal material as the upper electrode 33, the first reinforcing portion 6 on the support substrate 1 side in the insulating layer 4 is formed simultaneously with the lower electrode 31. And a manufacturing process in which the second reinforcing portion 6 opposite to the support substrate 1 side in the insulating layer 4 is formed at the same time as the upper electrode 33 can be adopted. Simplification and cost reduction can be achieved.

  Further, in the BAW resonator of the present embodiment, the reinforcing portions 6 and 6 are formed on both surfaces in the thickness direction of the insulating layer 4 as shown in FIG. 1, but the support in the insulating layer 4 is shown in FIG. The reinforcing portion 6 may be formed only on one surface of the substrate 1 side, or the reinforcing portion 6 may be formed only on one surface of the insulating layer 4 opposite to the supporting substrate 1 side as shown in FIG. Good. However, when the reinforcing portions 6 and 6 are formed on both surfaces in the thickness direction of the insulating layer 4 as shown in FIG. 1, further robustness can be achieved as compared with the configurations of FIGS. 4 and 5.

In the BAW resonator of the present embodiment, the piezoelectric layer 32 is formed of a lead-based piezoelectric material as described above. However, since the support substrate 1 is formed of MgO or SrTiO ₃ , the support substrate 1 is made of Si. The crystallinity of the piezoelectric layer 32 can be improved and the mechanical quality factor of the entire resonator 3 can be improved as compared with the case where it is formed of GaAs, glass, or the like.

(Embodiment 2)
The basic configuration of the BAW resonator according to the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 6, the first reinforcing portion 6 and the insulating layer 4 formed on the support substrate 1 side in the insulating layer 4 are used. The only difference is that each of the second reinforcing portions 6 formed on the side opposite to the supporting substrate 1 side is formed only on the peripheral portion of the etching hole 5. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Incidentally, in the present embodiment as well, the reinforcing portions 6 and 6 are formed on both surfaces in the thickness direction of the insulating layer 4 as in the configuration of FIG. 1 of the first embodiment, but one surface of the insulating layer 4 on the support substrate 1 side. The reinforcing part 6 may be formed only on the insulating layer 4, or the reinforcing part 6 may be formed only on one surface of the insulating layer 4 opposite to the support substrate 1 side.

  In the BAW resonance device of each of the embodiments described above, the deformation of the insulating layer 4 due to the stress generated in the peripheral portion of the etching hole 5 in the insulating layer 4 when the recess 2 is formed on the one surface of the support substrate 1. It is desirable to appropriately set the material, pattern, thickness, film forming method, and the like of the reinforcing portion 6 according to the material, thickness, film forming method, and the like of the insulating layer 4.

  In the BAW resonance apparatus described in each of the above embodiments, only one resonator 3 is formed on the one surface side of the support substrate 1, but the resonator 3 is disposed on the one surface side of the support substrate 1. If a plurality of resonators 3 are formed and connected so as to form a ladder filter, for example, a filter having a sharp cutoff characteristic and a wide bandwidth in a high frequency band of 2 GHz or more, for example, for UWB It can be used as a filter.

The BAW resonance apparatus of Embodiment 1 is shown, (a) is a schematic sectional drawing, (b) is a schematic plan view. It is principal process sectional drawing for demonstrating the manufacturing method of a BAW resonance apparatus same as the above. It is principal process sectional drawing for demonstrating the manufacturing method of a BAW resonance apparatus same as the above. It is a schematic sectional drawing which shows the other structural example of a BAW resonance apparatus same as the above. It is a schematic sectional drawing which shows another structural example of a BAW resonance apparatus same as the above. The BAW resonance apparatus of Embodiment 2 is shown, (a) is a schematic sectional drawing, (b) is a schematic plan view. The BAW resonance apparatus of a prior art example is shown, (a) is a schematic sectional drawing, (b) is a principal part schematic plan view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Recess 3 Resonator 4 Insulating layer 4a Opening part 5 Etching hole 6 Reinforcement part 31 Lower electrode 32 Piezoelectric layer 33 Upper electrode

Claims (7)

  A support substrate, a resonator formed on one surface side of the support substrate and having a laminated structure of a lower electrode, a piezoelectric layer, and an upper electrode, and formed on the one surface side of the support substrate and supported by the support substrate and resonating in plan view And a recess that exposes the lower electrode of the resonator and the surface of the insulating layer on the side of the support substrate is formed on the one surface of the support substrate. In addition, an etching hole for forming a recess communicating with the recess is formed in the periphery of the resonator in the insulating layer, and the peripheral portion of the etching hole in the insulating layer is reinforced and electrically insulated from the resonator. A BAW resonance device, wherein a reinforcing portion made of a metal material is formed on an insulating layer. 2. The BAW resonance device according to claim 1, wherein the support substrate is made of MgO or SrTiO ₃ , and the piezoelectric layer is made of a lead-based piezoelectric material.   3. The BAW resonance device according to claim 1, wherein the reinforcing portion is made of the same metal material as that of the lower electrode, and is formed on the support substrate side in the insulating layer.   3. The BAW resonance device according to claim 1, wherein the reinforcing portion is made of the same metal material as the upper electrode, and is formed on a side opposite to the support substrate side in the insulating layer. .   The reinforcing portion is formed on both surfaces of the insulating layer in the thickness direction, and the reinforcing portion formed on the insulating substrate on the support substrate side is made of the same metal material as the lower electrode, and the insulating layer 3. The BAW resonance device according to claim 1, wherein the reinforcing portion formed on the side opposite to the support substrate side is made of the same metal material as the upper electrode.   6. The metal material of each of the lower electrode and the upper electrode is at least one selected from the group consisting of Pt, Mo, W, Ir, Cr, and Ru. 2. The BAW resonance device according to item 1.   7. The method of manufacturing a BAW resonance device according to claim 1, wherein a reinforcing portion forming step of forming a reinforcing portion on the one surface side of the support substrate, and a reinforcing portion forming step are performed. An etching hole forming step for forming an etching hole in the insulating layer, and a recess forming step for forming a recess in the one surface of the support substrate through the etching hole after the etching hole forming step. A method for manufacturing a resonant device.

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