阅读说明：本技术 提高fbar滤波器制备良率的方法以及fbar滤波器 (Method for improving preparation yield of FBAR (film bulk acoustic resonator) filter and FBAR filter ) 是由 李国强 于 2019-08-27 设计创作，主要内容包括：本发明提供一种提高FBAR滤波器制备良率的方法以及FBAR滤波器,该方法包括：在第一基板上生成压电薄膜,并形成至少一个第一电极；形成支撑层,对支撑层进行刻蚀形成第一支撑层空腔,在支撑层一侧形成第一键合层；在键合衬底的一侧第二键合层,另一侧形成至少一个标记点,在键合衬底上形成贯穿键合衬底的第一通孔；将第一键合层与第二键合层键合连接,去除第一基板,在压电薄膜远离第一电极一侧形成顶电极以及与第一电极连接的电极上引结构,以形成FBAR滤波器。本在制备过程中无需使用牺牲层,保留了压电薄膜的完整性,并且这种在键合衬底上开孔的结构设计,结构稳定,不易塌陷,可以很好的改善压电薄膜的品质。(The invention provides a method for improving the preparation yield of an FBAR filter and the FBAR filter, wherein the method comprises the following steps: generating a piezoelectric film on a first substrate and forming at least one first electrode; forming a supporting layer, etching the supporting layer to form a first supporting layer cavity, and forming a first bonding layer on one side of the supporting layer; forming at least one mark point on the second bonding layer on one side of the bonding substrate and on the other side of the bonding substrate, and forming a first through hole penetrating through the bonding substrate on the bonding substrate; and bonding and connecting the first bonding layer and the second bonding layer, removing the first substrate, and forming a top electrode and an electrode up-lead structure connected with the first electrode on one side of the piezoelectric film, which is far away from the first electrode, so as to form the FBAR filter. The integrity of the piezoelectric film is kept without using a sacrificial layer in the preparation process, and the structural design of opening the holes on the bonding substrate has stable structure and is not easy to collapse, so that the quality of the piezoelectric film can be well improved.)

1. A method for improving the production yield of an FBAR filter, the method comprising:

s1: generating a piezoelectric film on a first substrate, and forming at least one first electrode on one side of the piezoelectric film, which is far away from the first substrate;

s2: forming a supporting layer covering the first electrode, etching the supporting layer to form a first supporting layer cavity, and forming a first bonding layer on one side of the supporting layer, which is far away from the piezoelectric film;

s3: forming a second bonding layer used for being in bonding connection with the first bonding layer on one side of a bonding substrate, forming at least one mark point on the other side of the bonding substrate, and forming a first through hole penetrating through the bonding substrate on the bonding substrate, wherein the positions of the first bonding layer and the first through hole on the bonding substrate respectively correspond to the positions of the first bonding layer and the first supporting layer cavity on the first base plate;

s4: and bonding and connecting the first bonding layer and the second bonding layer, removing the first substrate, and forming a top electrode and an electrode up-leading structure connected with the first electrode on one side of the piezoelectric film, which is far away from the first electrode, so as to form the FBAR filter.

2. The method of claim 1, wherein the step of forming a support layer covering the first electrode comprises:

forming a first insulating layer with the same thickness as the first electrode on one side of the piezoelectric film, which is far away from the first substrate, and removing the first insulating layer on the first electrode;

and forming a second insulating layer on the first insulating layer and the first electrode layer, and performing polishing treatment on the second insulating layer to form a supporting layer.

3. The method of claim 1, wherein the step of forming a support layer covering the first electrode comprises:

and forming a third insulating layer covering the first electrode on one side of the piezoelectric film, which is far away from the first substrate, and forming a supporting layer through the third insulating layer.

4. The method of claim 1, wherein the step of etching the support layer to form the first support layer cavity comprises:

and carrying out patterned etching on the supporting layer to form two first supporting layer cavities which are arranged at intervals and contact the first electrode.

5. The method of claim 1, wherein the step of forming the first bonding layer on the side of the supporting layer away from the piezoelectric film comprises;

and forming a first bonding layer on one side of the support layer, which is far away from the piezoelectric film, by one of sputtering, electron beam evaporation and a reaction vapor deposition method.

6. The method for improving the manufacturing yield of the FBAR filter as claimed in claim 1, wherein the two markers are spaced apart from the bonding substrate on a side away from the second bonding layer opposite to the second bonding layer.

7. The method of improving FBAR filter manufacturing yield of claim 1, wherein said forming a first via through said bond substrate on said bond substrate further comprises:

and forming a second supporting layer cavity on one side of the bonding substrate, which is provided with the second bonding layer, wherein the position of the second supporting layer cavity on the bonding substrate corresponds to the position of the first supporting layer cavity on the first base plate.

8. The method of claim 1, wherein the step of forming a top electrode and an electrode lead-up structure connected to the first electrode interconnection hole on the side of the piezoelectric film away from the first electrode comprises:

forming an electrode upper lead hole penetrating through the piezoelectric film on the piezoelectric film, and forming a top electrode in a region, which is far away from one side of the first electrode and is not penetrated through by the electrode upper lead hole, of the piezoelectric film;

and forming an electrode upper lead structure for filling the electrode upper lead hole, wherein the electrode upper lead structure is connected with the first electrode through the electrode upper lead hole and partially extends to one side of the piezoelectric film, which is far away from the first electrode.

9. The method of claim 8, wherein the number of the top electrode and the electrode lead-up structure is two, and one top electrode is connected to one electrode lead-up structure.

10. An FBAR filter obtained by the method of any one of claims 1 to 9 for improving production yield of the FBAR filter.

Technical Field

The invention relates to the technical field of electronic communication devices, in particular to a method for improving the preparation yield of an FBAR filter and the FBAR filter.

Background

The multifunctional development of the wireless communication terminal puts high technical requirements on miniaturization, high frequency, high performance, low power consumption, low cost and the like on a radio frequency device. The traditional surface acoustic wave filter (SAW) has large insertion loss in a high frequency band above 2.4GHz, and the dielectric filter has good performance but large volume. The Film Bulk Acoustic Resonator (FBAR) technology is a new radio frequency device technology which has appeared in recent years along with the improvement of the technological level of processing and the rapid development of modern wireless communication technology, especially personal wireless communication technology. The surface acoustic wave resonator has the advantages of extremely high quality factor Q value (more than 1000) and being capable of being integrated on an IC chip, and is compatible with a Complementary Metal Oxide Semiconductor (CMOS) process, and meanwhile, the defect that the surface acoustic wave resonator and the dielectric resonator cannot be compatible with the CMOS process is effectively avoided.

The basic principle of FBAR is based on the mechanical and electrical energy conversion of piezoelectric materials, so the quality factor of the piezoelectric composite membrane affects the loss and roll-off characteristics of FBAR filters. Generally FBAR filters are shown in figure 1. The device comprises a substrate, an air cavity on the substrate, and a bottom electrode, a piezoelectric layer and a top electrode which are sequentially manufactured on the substrate across the air cavity. The general process method is as follows: a pit is first anisotropically etched on a substrate, and then the pit is filled with a sacrificial layer material, which may be Al, Mg, Ge or silicon dioxide. And sputtering to grow a metal film on the surface of the sacrificial layer after CMP polishing, and etching a bottom electrode pattern at a position above the sacrificial layer correspondingly. Then a layer of piezoelectric film is deposited above the bottom electrode, after etching, the piezoelectric film covers the boundary of the pit on the substrate and exposes the leading-out end of the bottom electrode, and then a layer of metal film is deposited on the piezoelectric film, and the top electrode pattern is etched. A release window is then etched in the piezoelectric layer by dry etching to expose portions of the sacrificial layer. And finally, releasing the sacrificial layer from the etched release window, and manufacturing the FBAR on the substrate across the air cavity, wherein the sacrificial layer releasing method leaves a plurality of release channel holes on the piezoelectric layer, so that the piezoelectric film is greatly damaged, the cavity structure is easy to collapse, the Q value and the electromechanical coupling coefficient are low, the insertion loss is large, and the performance of the device is influenced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for improving the preparation yield of an FBAR filter and the FBAR filter, in the preparation process, a sacrificial layer is not needed, and the integrity of a piezoelectric film is kept, so that the problem of adverse effect on the structure of the filter in the process of removing the sacrificial layer is solved.

In order to solve the above problems, the present invention adopts a technical solution as follows: a method of improving FBAR filter fabrication yield, the method comprising: s1: generating a piezoelectric film on a first substrate, and forming at least one first electrode on one side of the piezoelectric film, which is far away from the first substrate; s2: forming a supporting layer covering the first electrode, etching the supporting layer to form a first supporting layer cavity, and forming a first bonding layer on one side of the supporting layer, which is far away from the piezoelectric film; s3: forming a second bonding layer used for being in bonding connection with the first bonding layer on one side of a bonding substrate, forming at least one mark point on the other side of the bonding substrate, and forming a first through hole penetrating through the bonding substrate on the bonding substrate, wherein the positions of the first bonding layer and the first through hole on the bonding substrate respectively correspond to the positions of the first bonding layer and the first supporting layer cavity on the first base plate; s4: and bonding and connecting the first bonding layer and the second bonding layer, removing the first substrate, and forming a top electrode and an electrode up-leading structure connected with the first electrode on one side of the piezoelectric film, which is far away from the first electrode, so as to form the FBAR filter.

Further, the step of forming a support layer covering the first electrode specifically includes: forming a first insulating layer with the same thickness as the first electrode on one side of the piezoelectric film, which is far away from the first substrate, and removing the first insulating layer on the first electrode; and forming a second insulating layer on the first insulating layer and the first electrode layer, and performing polishing treatment on the second insulating layer to form a supporting layer.

Further, the step of forming a support layer covering the first electrode specifically includes: and forming a third insulating layer covering the first electrode on one side of the piezoelectric film, which is far away from the first substrate, and forming a supporting layer through the third insulating layer.

Further, the step of etching the support layer to form a first support layer cavity specifically includes: and carrying out patterned etching on the supporting layer to form two first supporting layer cavities which are arranged at intervals and contact the first electrode.

Further, the step of forming a first bonding layer on the side of the support layer away from the piezoelectric film specifically includes; and forming a first bonding layer on one side of the support layer, which is far away from the piezoelectric film, by one of sputtering, electron beam evaporation and a reaction vapor deposition method.

Furthermore, the number of the mark points is two, the mark points are opposite to the second bonding layer and are arranged on one side of the bonding substrate away from the second bonding layer at intervals.

Further, after the forming the first through hole penetrating through the bonding substrate on the bonding substrate, the method further includes: and forming a second supporting layer cavity on one side of the bonding substrate, which is provided with the second bonding layer, wherein the position of the second supporting layer cavity on the bonding substrate corresponds to the position of the first supporting layer cavity on the first base plate.

Further, the step of forming a top electrode and an electrode up-lead structure connected to the first electrode interconnection hole on the side of the piezoelectric film away from the first electrode specifically includes: forming an electrode upper lead hole penetrating through the piezoelectric film on the piezoelectric film, and forming a top electrode in a region, which is far away from one side of the first electrode and is not penetrated through by the electrode upper lead hole, of the piezoelectric film; and forming an electrode upper lead structure for filling the electrode upper lead hole, wherein the electrode upper lead structure is connected with the first electrode through the electrode upper lead hole and partially extends to one side of the piezoelectric film, which is far away from the first electrode.

Furthermore, the number of the top electrode and the number of the electrode upper lead structures are two, and one top electrode is connected with one electrode upper lead structure.

Based on the same inventive concept, the invention also provides a monolithically integrated radio frequency device, wherein the FBAR filter is obtained by the method for improving the preparation yield of the FBAR filter.

Compared with the prior art, the invention has the beneficial effects that: the first bonding layer and the second bonding layer are bonded and connected, so that the cavity of the first supporting layer is opposite to the cavity of the second supporting layer to form a closed cavity, and the first through hole penetrating through the closed cavity is formed in the bonding substrate.

Drawings

FIG. 1 is a diagram of an embodiment of a conventional FBAR filter;

FIG. 2 is a flowchart illustrating an embodiment of a method for improving the yield of FBAR filter manufacturing according to the present invention;

FIG. 3 is a schematic diagram illustrating an embodiment of forming a piezoelectric film on a first substrate in the method for improving the yield of FBAR filters according to the present invention;

FIG. 4 is a schematic diagram illustrating an embodiment of forming a first electrode on a piezoelectric film in the method for improving the yield of FBAR filters according to the present invention;

FIG. 5 is a schematic diagram illustrating an embodiment of forming a first insulating layer in the method for improving the yield of FBAR filter manufacturing according to the present invention;

FIG. 6 is a schematic diagram illustrating an embodiment of forming a second insulating layer in the method for improving the yield of the FBAR filter;

FIG. 7 is a schematic diagram illustrating an embodiment of forming a support layer in the method for improving the yield of FBAR filter fabrication according to the present invention;

FIG. 8 is a schematic diagram illustrating the formation of supporting layer cavities according to an embodiment of the present invention in a method for improving the yield of FBAR filter fabrication;

FIG. 9 is a diagram illustrating an embodiment of forming a first bonding layer in the method for improving the yield of FBAR filter fabrication according to the present invention;

FIG. 10 is a diagram illustrating an embodiment of forming a second bonding layer on a bonding substrate in the method for improving the manufacturing yield of FBAR filters according to the present invention;

FIG. 11 is a diagram illustrating an embodiment of forming first vias in a method for improving the yield of FBAR filter fabrication according to the present invention;

FIG. 12 is a schematic diagram illustrating the formation of a cavity of a second support layer according to an embodiment of the present invention;

FIG. 13 is a schematic diagram illustrating an embodiment of bonding and connecting a first bonding layer and a second bonding layer in the method for improving the yield of FBAR filter fabrication according to the present invention;

fig. 14 is a structural diagram of an embodiment of bonding and connecting a first bonding layer and a second bonding layer in the method for improving the manufacturing yield of the FBAR filter according to the present invention;

FIG. 15 is a schematic view illustrating an embodiment of removing the first substrate in the method for improving the yield of FBAR filter manufacturing according to the present invention;

FIG. 16 is a diagram illustrating an embodiment of forming via holes on electrodes in the method for improving the yield of FBAR filters according to the present invention;

FIG. 17 is a diagram illustrating an embodiment of forming a top electrode and an electrode pull-up structure in the method for improving the yield of FBAR filter fabrication according to the present invention;

fig. 18 is a structural diagram of an FBAR filter formed in the method for improving the manufacturing yield of the FBAR filter according to an embodiment of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

Referring to fig. 2-18, fig. 2 is a flow chart illustrating a method for increasing the yield of FBAR filter manufacturing according to an embodiment of the present invention; FIG. 3 is a schematic diagram illustrating an embodiment of forming a piezoelectric film on a first substrate in the method for improving the yield of FBAR filters according to the present invention; FIG. 4 is a schematic diagram illustrating an embodiment of forming a first electrode on a piezoelectric film in the method for improving the yield of FBAR filters according to the present invention; FIG. 5 is a schematic diagram illustrating an embodiment of forming a first insulating layer in the method for improving the yield of FBAR filter manufacturing according to the present invention; FIG. 6 is a schematic diagram illustrating an embodiment of forming a second insulating layer in the method for improving the yield of the FBAR filter; FIG. 7 is a schematic diagram illustrating an embodiment of forming a support layer in the method for improving the yield of FBAR filter fabrication according to the present invention; FIG. 8 is a schematic diagram illustrating the formation of supporting layer cavities according to an embodiment of the present invention in a method for improving the yield of FBAR filter fabrication; FIG. 9 is a diagram illustrating an embodiment of forming a first bonding layer in the method for improving the yield of FBAR filter fabrication according to the present invention; FIG. 10 is a diagram illustrating an embodiment of forming a second bonding layer on a bonding substrate in the method for improving the manufacturing yield of FBAR filters according to the present invention; FIG. 11 is a diagram illustrating an embodiment of forming first vias in a method for improving the yield of FBAR filter fabrication according to the present invention; FIG. 12 is a schematic diagram illustrating the formation of a cavity of a second support layer according to an embodiment of the present invention; FIG. 13 is a schematic diagram illustrating an embodiment of bonding and connecting a first bonding layer and a second bonding layer in the method for improving the yield of FBAR filter fabrication according to the present invention; fig. 14 is a structural diagram of an embodiment of bonding and connecting a first bonding layer and a second bonding layer in the method for improving the manufacturing yield of the FBAR filter according to the present invention; FIG. 15 is a schematic view illustrating an embodiment of removing the first substrate in the method for improving the yield of FBAR filter manufacturing according to the present invention; FIG. 16 is a diagram illustrating an embodiment of forming via holes on electrodes in the method for improving the yield of FBAR filters according to the present invention; FIG. 17 is a diagram illustrating an embodiment of forming a top electrode and an electrode pull-up structure in the method for improving the yield of FBAR filter fabrication according to the present invention; fig. 18 is a structural diagram of an FBAR filter formed in the method for improving the manufacturing yield of the FBAR filter according to an embodiment of the present invention. The method for improving the manufacturing yield of the FBAR filter according to the present invention will be described in detail with reference to fig. 2 to 18.

In this embodiment, the FBAR filter formed by the method for improving the production yield of the FBAR filter includes a bonding substrate and a second bonding layer bonded to the first bonding layer, the supporting layer is disposed on a side of the first bonding layer away from the second bonding layer, the at least one first electrode is disposed on a side of the supporting layer away from the first bonding layer, a supporting layer cavity is formed between the first electrode and the bonding substrate, the piezoelectric film is disposed on a side of the first electrode away from the bonding substrate, the electrode lead-up structure penetrates through the piezoelectric film and is connected to the first electrode, and the top electrode is disposed on a side of the piezoelectric film away from the first electrode and is connected to the electrode lead-up structure.

In this embodiment, the method for improving the yield of the FBAR filter includes the following steps:

s1: a piezoelectric film is formed on a first substrate, and at least one first electrode is formed on the piezoelectric film on a side away from the first substrate.

In this embodiment, the first substrate 102 is used as a growth substrate of the piezoelectric thin film 101, and the first substrate 102 may be at least one of a silicon substrate, a sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, an aluminum nitride substrate, an AlxGa1-xN buffer layer substrate, a LiGaO2, glass, and a metal substrate, and in other embodiments, may be another substrate that can be used as a growth substrate of the piezoelectric thin film 101, and is not limited herein.

The structure 100 in fig. 3 includes a piezoelectric thin film 101 and a first substrate 102, where the piezoelectric thin film 101 covers the first substrate 102, and may be a high-quality single crystal piezoelectric thin film grown by epitaxy, a high C-axis oriented polycrystalline piezoelectric thin film grown by sputtering, or a thin film with piezoelectric properties such as AlN, ZnO, PZT, or the like.

In the present embodiment, the thickness of the piezoelectric thin film 101 is 0.02 to 10 micrometers.

Fig. 4 shows a schematic view of a structure 200 in which a first electrode 103 is formed on a piezoelectric thin film 101, the first electrode 103 is formed on a side of the piezoelectric thin film 101 away from a first substrate 102 by an electron beam lift-off method or a magnetron sputtering method, and partially covers the first substrate 102, wherein a thickness of the first electrode 103 is between 0.1 nm and 500 nm, and a material forming the first electrode 103 may be one or more of Al, Mo, W, Pt, Cu, Ag, Au, and ZrN, or may be other materials with good conductivity, such as non-metallic materials like graphene.

In a specific embodiment, the number of the first electrodes 103 is 4, and the first electrodes are spaced apart from each other on the side of the piezoelectric film 101 away from the first substrate 102.

S2: and forming a supporting layer covering the first electrode, etching the supporting layer to form a first supporting layer cavity, and forming a first bonding layer on one side of the supporting layer, which is far away from the piezoelectric film.

In this embodiment, the support layer 106 covering the first electrode 103 may be formed of the first insulating layer 104 and the second insulating layer 105 formed on the piezoelectric thin film 101, or may be formed of a third insulating layer covering the first electrode 103. Wherein structure 300 in fig. 5 is a schematic diagram of forming first insulating layer 104, structure 301 in fig. 6 is a schematic diagram of forming second insulating layer 105, structure 302 in fig. 7 is a schematic diagram of forming support layer 106, fig. 8 is a schematic diagram of etching support layer 106 to form first support layer cavity 107, and fig. 9 is a schematic diagram of forming first bonding layer 108 on support layer 106.

In a preferred embodiment, a first insulating layer 104 with the same thickness as the first electrode 103 is formed on the side of the piezoelectric thin film 101 away from the first substrate 102, and the first insulating layer 104 on the first electrode 103 is removed; a second insulating layer 105 is formed on the first insulating layer 104 and the first electrode 103 layer, and the second insulating layer 105 is subjected to a planarization process to form a support layer 106.

Wherein, the first insulating layer 104 separates the first electrode 103, the first insulating layer 104 on the first electrode 103 is removed by means of wet or dry etching, and the second insulating layer 105 covers the first electrode 103 and the first insulating layer 104.

In another preferred embodiment, a third insulating layer is formed on the piezoelectric film 101 on the side away from the first substrate 102 to cover the first electrode 103, and the support layer 106 is formed through the third insulating layer. Wherein the support layer 106 is formed by mechanical polishing and planarization through the third insulating layer.

In the present embodiment, the first insulating layer 104, the second insulating layer 105, and the third insulating layer are made of a dielectric material such as SiO2 or Si3N4, but the first insulating layer 104, the second insulating layer 105, and the third insulating layer may be made of another dielectric material that can insulate the first electrode 103, and are not limited thereto.

In a specific embodiment, the first support layer cavities 107 are formed by patterned etching of the support layer 106, and are two in number, spaced apart and in contact with different first electrodes 103.

In this embodiment, the first bonding layer 108 is formed on the side of the supporting layer 106 away from the piezoelectric film 101 by forming the first bonding layer 108 on the side of the supporting layer 106 away from the piezoelectric film 101 by one of sputtering, electron beam evaporation, and reactive vapor deposition. The first bonding layer 108 may be a metal or a non-metal material, and any bonding method and material commonly used in the industry may be used for the first bonding layer 108.

In a specific embodiment, a first bonding layer 108 covers a portion of handle layer 106 on a side away from first electrode 103 where a cavity of handle layer 106 is disposed, and other structures of the FBAR filter are connected through first bonding layer 108.

S3: and forming a second bonding layer used for being in bonding connection with the first bonding layer on one side of the bonding substrate, forming at least one mark point on the other side of the bonding substrate, and forming a first through hole penetrating through the bonding substrate on the bonding substrate, wherein the positions of the first bonding layer and the first through hole on the bonding substrate respectively correspond to the positions of the first bonding layer and the first supporting layer cavity on the first base plate.

In the present embodiment, the bond substrate 109 may be made of at least one of a silicon substrate, a sapphire substrate, a silicon carbide substrate, a gallium nitride substrate, an aluminum nitride substrate, and an AlxGa1-xN buffer layer substrate, as in the case of the material of the first substrate 102.

The structure 500 in fig. 10 is a schematic diagram of forming the second bonding layer 112 on the bonding substrate 109, and in this embodiment, the manner and the material used for forming the second bonding layer 112 may be the same as or different from those of the first bonding layer 108, and only the first bonding layer 108 and the second bonding layer are required to be connected, which is not limited herein.

In the present embodiment, the thickness of the second bonding layer 112 is 0.3 to 3 micrometers, and the thickness of the cavity of the second support layer is 0.5 to 3 micrometers.

In this embodiment, the mark points 110 are two grooves on the bonding substrate 109, which are opposite to the second bonding layer 112, located on two sides of the cavity of the second support layer, and spaced apart from one side of the bonding substrate 109 away from the second bonding layer 112. In other embodiments, the number of the mark points 110 may also be one, three or another, and only the mark points 110 are required to achieve the aligned bonding of the first base plate 102 and the bonding substrate 109 and to form the first through holes 111 penetrating through the bonding substrate 109.

Fig. 11 is a schematic diagram of forming first through holes 111 on a bonding substrate 109, in this embodiment, the number of the first through holes 111 is 2, and the first through holes 111 are disposed in a region of a second bonding layer 112 at a position of the bonding substrate 109, in other embodiments, the number of the first through holes 111 may be 1, 3, or other numbers, and only the position of the first through hole 111 corresponds to the position of the first support layer cavity 107, and after the first bonding layer 108 and the second bonding layer 112 are bonded and connected, air in the first support layer cavity 107 can be exhausted through the first through hole 111, which is not limited herein.

In this embodiment, the first through hole 111 may be circular, and the aperture is 2 micrometers to 30 micrometers, in other embodiments, the first through hole 111 may also be in other shapes, and only the first through hole 111 penetrates through the bonding substrate 109, which is not limited herein.

The structure 601 in fig. 12 is a schematic diagram of forming a second support layer cavity on the bonding substrate 109, after forming the first through hole 111 penetrating through the bonding substrate 109 on the bonding substrate 109, forming a second support layer cavity on the side of the bonding substrate 109 where the second bonding layer 112 is disposed, where the position of the second support layer cavity on the bonding substrate 109 corresponds to the position of the first support layer cavity 107 on the first base plate 102.

In this embodiment, the second support layer cavity is formed by etching the bonding substrate 109, is disposed on the side of the bonding substrate 109 where the second bonding layer 112 is disposed, is located on the region of the bonding substrate 109 where the second bonding layer 112 is not formed, and is connected to the first through hole 111.

In the present embodiment, the number of the cavities of the second support layer is 2, and the cavities are respectively connected to different first through holes 111.

S4: and bonding and connecting the first bonding layer and the second bonding layer, removing the first substrate, and forming a top electrode and an electrode up-lead structure connected with the first electrode on one side of the piezoelectric film, which is far away from the first electrode, so as to form the FBAR filter.

Fig. 13 is a schematic diagram of a structure 700 in fig. 13 illustrating bonding connection between a first bonding layer 108 and a second bonding layer 112, and fig. 14 is a structural diagram of a device formed by bonding connection between the first bonding layer 108 and the second bonding layer 112, in this embodiment, the bonding connection between the first bonding layer 108 and the second bonding layer 112 may be different bonding connection manners according to the environment of the wafer and the materials of the first bonding layer 108 and the second bonding layer 112, where the bonding connection manner may be a metal diffusion or a metal eutectic bonding manner, if a metal diffusion or a metal eutectic bonding is adopted, a high vacuum and a high temperature condition may be encountered during the bonding process, if there is no first through hole 111, the bonding is completed under a vacuum condition, and after the bonding is completed, a closed cavity formed by a cavity 107 of the first support layer and a cavity of the second support layer is a closed space, after the first substrate 102 is subsequently removed, the piezoelectric film 101 is crushed by atmospheric pressure without the constraint of the first substrate 102, so that the piezoelectric film 101 is broken, the device fails, if the strength of the piezoelectric film 101 is enough and the piezoelectric film 101 is not broken, the piezoelectric film 101 has large stress, the performance of the device is greatly affected, and the closed cavity is also cracked due to thermal expansion in the subsequent process under the condition of hundreds of degrees centigrade.

Fig. 15 is a schematic diagram of removing the first substrate 102, and in this embodiment, the first substrate 102 is removed by laser lift-off or mechanical thinning combined with wet etching or dry etching.

The step of forming the top electrode and the electrode up-drawing structure 115 connected with the interconnection hole of the first electrode 103 on the side of the piezoelectric film 101 away from the first electrode 103 includes: forming an electrode upper lead hole 114 penetrating through the piezoelectric thin film 101 on the piezoelectric thin film 101, and forming a top electrode in a region of the piezoelectric thin film 101, which is far away from the first electrode 103 and is not penetrated through by the electrode upper lead hole 114; an electrode lead-up structure 115 filling the electrode lead-up hole 114 is formed, wherein the electrode lead-up structure 115 is connected to the first electrode 103 through the electrode lead-up hole 114 and partially extends to the side of the piezoelectric film 101 away from the first electrode 103.

Fig. 16 is a schematic diagram of forming an electrode upper lead hole 114 on the piezoelectric film 101, and fig. 17 is a schematic diagram of forming an electrode upper lead structure 115 and a top electrode, in this embodiment, the electrode upper lead hole 114 is formed by dry etching or wet etching, and the top electrode and the electrode upper lead structure 115 are formed by sputtering or electron beam evaporation.

Fig. 18 is a structural diagram of the FBAR filter, in this embodiment, the number of the electrode lead-up structures 115 and the number of the top electrodes are 2, the electrode lead-up structures 115 and the top electrodes are sequentially arranged, and one of the top electrodes located in the middle of the piezoelectric film 101 is connected to one of the electrode lead-up structures 115. In other embodiments, the number of the electrode lead-up structures 115 and the top electrode may also be 1 or other numbers, which are not limited herein.

In the present embodiment, the material forming the top electrode is one or a combination of two of Al, Mo, W, Pt, Cu, Ag, Au, ZrN, and has a thickness of 20 nm to 500 nm.

In the present embodiment, the FBAR filter formed is an FBAR filter of any frequency, including an FBAR filter in a frequency range from 10MHZ to 100 GHZ.

Has the advantages that: the first bonding layer and the second bonding layer are bonded and connected, so that the cavity of the first supporting layer is opposite to the cavity of the second supporting layer to form a closed cavity, and the first through hole penetrating through the closed cavity is formed in the bonding substrate.

Based on the same inventive concept, the present invention further provides an FBAR filter, wherein the FBAR filter is obtained by the method for improving the preparation yield of the FBAR filter according to the above embodiment, which is not described herein again.

In the embodiments provided in the present invention, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the modules or partitions may be merely logical partitions, and may be implemented in other ways, e.g., multiple modules or components may be combined or integrated into another system, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, devices or indirect coupling or communication connection, and may be in an electrical, mechanical or other form.

The components described as separate parts may or may not be physically separate, and the components shown may or may not be physical, that is, may be located in one place, or may be distributed on a plurality of networks. Some or all of them can be selected according to actual needs to achieve the purpose of the embodiment.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.