阅读说明：本技术 高频声波谐振器及其制备方法 (high-frequency acoustic wave resonator and preparation method thereof ) 是由 欧欣 周鸿燕 张师斌 李忠旭 黄凯 赵晓蒙 于 2019-09-17 设计创作，主要内容包括：本发明提供一种基于极低声阻部件的高频声波谐振器及其制备方法,高频声波谐振器的制备方法包括如下步骤：1)制备极低声阻部件；2)于所述极低声阻部件的上表面上形成压电膜；3)于所述压电膜的上表面形成图案化上电极。本发明的高频声波谐振器及其制备方法,通过在压电膜下设置极低声阻部件,增大压电膜与其下方的极低声阻部件的阻抗差,可有效激发高声速弹性波(如S0波),在加强对其界面反射的同时并将其机械能有效约束在压电膜中,从而在提高声表面波谐振器频率的同时,使其保持较高的Q值；避免了高频声表面波谐振器所激发的高声速弹性波大量向衬底泄露而导致的器件性能严重退化的问题的发生。(The invention provides a high-frequency acoustic wave resonator based on an extremely low acoustic resistance component and a preparation method thereof, wherein the preparation method of the high-frequency acoustic wave resonator comprises the following steps: 1) preparing an extremely low acoustic resistance part; 2) forming a piezoelectric film on an upper surface of the extremely low acoustic resistance member; 3) and forming a patterned upper electrode on the upper surface of the piezoelectric film. According to the high-frequency acoustic wave resonator and the preparation method thereof, the extremely low acoustic resistance component is arranged under the piezoelectric film, so that the impedance difference between the piezoelectric film and the extremely low acoustic resistance component below the piezoelectric film is increased, high-sound-velocity elastic waves (such as S0 waves) can be effectively excited, the reflection on the interface of the piezoelectric film is enhanced, and the mechanical energy of the piezoelectric film is effectively restrained in the piezoelectric film, so that the frequency of the surface acoustic wave resonator is improved, and meanwhile, the Q value of the surface acoustic wave resonator is kept high; the problem of serious degradation of device performance caused by the leakage of a large amount of high-sound-speed elastic waves excited by the high-frequency surface acoustic wave resonator to the substrate is solved.)

1. A method for manufacturing a high-frequency acoustic wave resonator is characterized by comprising the following steps:

1) preparing an extremely low acoustic resistance part;

2) forming a piezoelectric film on an upper surface of the extremely low acoustic resistance member;

3) And forming a patterned upper electrode on the upper surface of the piezoelectric film.

2. The method for producing a high-frequency acoustic wave resonator according to claim 1, wherein the production of the extremely low acoustic resistance member in the step 1) includes the steps of:

1-1) providing a single-layer extremely-low acoustic resistance material layer, wherein the single-layer extremely-low acoustic resistance material layer is the extremely-low acoustic resistance part.

3. The method for producing a high-frequency acoustic wave resonator according to claim 1, wherein the production of the extremely low acoustic resistance member in the step 1) includes the steps of:

1-1) providing a substrate;

1-2) forming a single-layer extremely-low acoustic resistance material layer with a preset thickness on the upper surface of the substrate, wherein the single-layer extremely-low acoustic resistance material layer and the substrate jointly form the extremely-low acoustic resistance part.

4. the method for producing a high-frequency acoustic wave resonator according to claim 2 or 3, wherein the material of the single extremely low acoustic resistance material layer includes: at least one of benzocyclobutene, polyimide, polydimethylsiloxane and polystyrene.

5. The method of manufacturing a high-frequency acoustic wave resonator according to claim 1, wherein a material of the piezoelectric film includes at least one of lithium niobate, potassium niobate, lithium tantalate, and aluminum nitride, quartz, or zinc oxide.

6. the method of manufacturing a high-frequency surface acoustic wave resonator according to claim 1 or 2, wherein the piezoelectric film and the extremely low acoustic resistance material have an interface reflection coefficient R of more than 90% with respect to an elastic wave excited in the piezoelectric film; wherein the content of the first and second substances,Z1 is the acoustic impedance of the piezoelectric film to the elastic wave excited by the piezoelectric film, and Z2 is the acoustic impedance of the very low acoustic resistance material to the elastic wave excited by the piezoelectric film.

7. the method for producing a high frequency acoustic wave resonator according to claim 1, wherein the method for producing the extremely low acoustic resistance member in step 1) includes an ion beam peeling method, a bonding method, a deposition method, an epitaxial method or a spin coating method; the method for forming the piezoelectric film in the step 2) includes an ion beam stripping method, a bonding method, a deposition method or an epitaxial method.

8. The method according to claim 1, wherein the patterned upper electrode in step 3) includes a first fixed portion, a first interdigital, a second fixed portion, and a second interdigital, and the first fixed portion and the second fixed portion are arranged in parallel at intervals; the first interdigital is vertically fixed on the first fixing part; the second interdigital is vertically fixed on the second fixing part; the first interdigital and the second interdigital are alternately arranged between the first fixing part and the second fixing part at equal intervals in parallel.

9. The method for manufacturing a high-frequency acoustic wave resonator according to claim 8, wherein a ratio of a distance from the first interdigital to the second fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1, and a ratio of a distance from the second interdigital to the first fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1.

10. the method for manufacturing a high-frequency surface acoustic wave resonator according to claim 1, further comprising a step of forming a bottom electrode on an upper surface of the extremely low acoustic resistance member between the step 1) and the step 2); the piezoelectric film formed in step 2) is located on the upper surface of the bottom electrode.

11. A high-frequency acoustic wave resonator, characterized in that the high-frequency acoustic wave resonator comprises:

An extremely low acoustic resistance component;

a piezoelectric film on an upper surface of the extremely low acoustic resistance member;

And the patterned upper electrode is positioned on the upper surface of the piezoelectric film.

12. The high frequency acoustic wave resonator according to claim 11, wherein the extremely low acoustic resistance member comprises a single layer of an extremely low acoustic resistance material layer; or the extremely low acoustic resistance part comprises a substrate and a single-layer extremely low acoustic resistance material layer, and the single-layer extremely low acoustic resistance material layer is positioned on the upper surface of the substrate.

13. The high frequency acoustic wave resonator according to claim 12, wherein the material of the single layer of extremely low acoustic resistance material layer includes at least one of benzocyclobutene, polyimide, polydimethylsiloxane, and polystyrene.

14. the high-frequency acoustic wave resonator according to claim 11, characterized in that the material of the piezoelectric film comprises at least one of lithium niobate, potassium niobate, lithium tantalate, aluminum nitride, quartz, or zinc oxide.

15. The high frequency surface acoustic wave resonator of claim 11The preparation method is characterized in that the interface reflection coefficients R of the piezoelectric film and the extremely low acoustic resistance material to the elastic waves excited in the piezoelectric film are both larger than 90%; wherein the content of the first and second substances,Z1 is the acoustic impedance of the piezoelectric film to the elastic wave excited by the piezoelectric film, and Z2 is the acoustic impedance of the very low acoustic resistance material to the elastic wave excited by the piezoelectric film.

16. The high frequency acoustic resonator according to claim 11, wherein the patterned upper electrode includes a first fixed portion, a first interdigital, a second fixed portion, and a second interdigital, and the first fixed portion and the second fixed portion are arranged in parallel and spaced apart; the first interdigital is vertically fixed on the first fixing part; the second interdigital is vertically fixed on the second fixing part; the first interdigital and the second interdigital are alternately arranged between the first fixing part and the second fixing part at equal intervals in parallel.

17. the high-frequency acoustic wave resonator according to claim 16, wherein a ratio of a distance from the first interdigital to the second fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1, and a ratio of a distance from the second interdigital to the first fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1.

18. The high-frequency surface acoustic wave resonator according to claim 11, further comprising a bottom electrode between said extremely low acoustic resistance member and said piezoelectric film.

Technical Field

the invention belongs to the technical field of semiconductor preparation, and particularly relates to a high-frequency acoustic wave resonator and a preparation method thereof.

Background

With the advent of the 5G era, the demand for front-end filters, particularly high-frequency surface acoustic wave filters, for radio frequency communications has increased. When the elastic wave excited in the piezoelectric layer propagates between dielectric layers with different acoustic impedances, the acoustic impedance difference is smaller, and the interface reflection coefficient of the acoustic wave is smaller, so that the acoustic wave energy is easy to leak to the substrate layer, the working performance is poor, and even the excited high-sound-velocity mode disappears due to complete leakage. Therefore, the surface acoustic wave resonator integrated on the traditional substrate has low available working frequency due to small impedance difference between the piezoelectric layer and the substrate, and the working performance of the surface acoustic wave resonator is influenced by poor elastic wave energy constraint and leakage to the substrate.

disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a high frequency acoustic wave resonator and a method for manufacturing the same, which are used to solve the problems in the prior art that the operating frequency of the acoustic wave resonator is low, the restriction of the elastic wave energy is not good, and the elastic wave energy leaks to the substrate, thereby affecting the operating performance of the acoustic wave resonator.

in order to achieve the above and other related objects, the present invention provides a method for manufacturing a high frequency acoustic wave resonator, the method comprising the steps of:

1) Preparing an extremely low acoustic resistance part;

2) Forming a piezoelectric film on an upper surface of the extremely low acoustic resistance member;

3) And forming a patterned upper electrode on the upper surface of the piezoelectric film.

Optionally, the step 1) of preparing the extremely low acoustic resistance member includes the steps of:

1-1) providing a single-layer extremely-low acoustic resistance material layer, wherein the single-layer extremely-low acoustic resistance material layer is the extremely-low acoustic resistance part.

Optionally, the step 1) of preparing the extremely low acoustic resistance member includes the steps of:

1-1) providing a substrate;

1-2) forming a single-layer extremely-low acoustic resistance material layer on the upper surface of the substrate, wherein the single-layer extremely-low acoustic resistance material layer and the substrate jointly form the extremely-low acoustic resistance part.

Optionally, the material of the single-layer extremely low acoustic resistance material layer includes at least one of benzocyclobutene, polyimide, polydimethylsiloxane and polystyrene.

Optionally, the material of the piezoelectric film includes at least one of lithium niobate, potassium niobate, lithium tantalate, aluminum nitride, quartz, or zinc oxide.

Optionally, the interface reflection coefficients R of the piezoelectric film and the extremely low acoustic resistance material for the elastic waves excited in the piezoelectric film are both greater than 90%; wherein the content of the first and second substances,Z1 is the acoustic impedance of the piezoelectric film to the elastic wave excited by the piezoelectric film, and Z2 is the acoustic impedance of the very low acoustic resistance material to the elastic wave excited by the piezoelectric film.

Optionally, the high-frequency surface acoustic wave resonator further includes: a bottom electrode positioned between the high-velocity support substrate and the piezoelectric film.

Optionally, the preparation method of the extremely low acoustic resistance component in the step 1) includes an ion beam stripping method, a bonding method, a deposition method, an epitaxial method or a spin coating method; the method for forming the piezoelectric film in the step 2) includes an ion beam stripping method, a bonding method, a deposition method or an epitaxial method.

Optionally, the patterned upper electrode in step 3) includes a first fixed portion, a first finger, a second fixed portion, and a second finger, and the first fixed portion and the second fixed portion are arranged in parallel at intervals; the first interdigital is vertically fixed on the first fixing part; the second interdigital is vertically fixed on the second fixing part; the first interdigital and the second interdigital are alternately arranged between the first fixing part and the second fixing part at equal intervals in parallel.

Optionally, a ratio of a distance between the first interdigital and the second fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1, and a ratio of a distance between the second interdigital and the first fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1.

Optionally, a step of forming a bottom electrode on the upper surface of the extremely low acoustic resistance member is further included between step 1) and step 2); the piezoelectric film formed in step 2) is located on the upper surface of the bottom electrode.

The present invention also provides a high frequency acoustic wave resonator, including: an extremely low acoustic resistance component; a piezoelectric film on an upper surface of the extremely low acoustic resistance member; and the patterned upper electrode is positioned on the upper surface of the piezoelectric film.

Optionally, the very low acoustic resistance component comprises a single layer of very low acoustic resistance material layer; or the extremely low acoustic resistance part comprises a substrate and a single-layer extremely low acoustic resistance material layer, and the single-layer extremely low acoustic resistance material layer is positioned on the upper surface of the substrate.

Optionally, the material of the single-layer extremely low acoustic resistance material layer includes at least one of benzocyclobutene, polyimide, polydimethylsiloxane and polystyrene.

Optionally, the material of the piezoelectric film includes, but is not limited to, at least one of lithium niobate, potassium niobate, lithium tantalate, aluminum nitride, quartz, or zinc oxide.

Optionally, the interface reflection coefficients R of the piezoelectric film and the extremely low acoustic resistance material for the elastic waves excited in the piezoelectric film are both greater than 90%; wherein the content of the first and second substances,z1 is the acoustic impedance of the piezoelectric film to the elastic wave excited by the piezoelectric film, and Z2 is the acoustic impedance of the very low acoustic resistance material to the elastic wave excited by the piezoelectric film.

Optionally, the patterned upper electrode includes a first fixed portion, a first finger, a second fixed portion, and a second finger, and the first fixed portion and the second fixed portion are arranged in parallel at intervals; the first interdigital is vertically fixed on the first fixing part; the second interdigital is vertically fixed on the second fixing part; the first interdigital and the second interdigital are alternately arranged between the first fixing part and the second fixing part at equal intervals in parallel.

optionally, a ratio of a distance between the first interdigital and the second fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1, and a ratio of a distance between the second interdigital and the first fixed portion to a wavelength excited by the high-frequency acoustic wave resonator is 0.05 to 1.

optionally, the high-frequency surface acoustic wave resonator further includes a bottom electrode located between the extremely low acoustic resistance member and the piezoelectric film.

As described above, the high frequency acoustic wave resonator and the method for manufacturing the same according to the present invention have the following advantageous effects: according to the high-frequency acoustic wave resonator and the preparation method thereof, the extremely low acoustic resistance part is arranged under the piezoelectric film, so that the impedance difference between the piezoelectric film and the extremely low acoustic resistance part below the piezoelectric film is increased, high-sound-velocity elastic waves (such as S waves) can be effectively excited, and the mechanical energy of the high-sound-velocity elastic waves is effectively constrained in the piezoelectric film, so that the frequency of the surface acoustic wave resonator is improved, and meanwhile, the high Q value of the surface acoustic wave resonator is kept; the problem of serious degradation of device performance caused by the leakage of a large amount of high-sound-speed elastic waves excited by the high-frequency surface acoustic wave resonator to the substrate is solved.

drawings

Fig. 1 is a flow chart illustrating a method for manufacturing a high frequency acoustic wave resonator according to an embodiment of the present invention.

Fig. 2 to 5 are schematic perspective views illustrating structures obtained by steps of a method for manufacturing a high-frequency acoustic wave resonator according to a first embodiment of the present invention.

Fig. 6 is a schematic top view of the patterned upper electrode formed in step 3) of the method for manufacturing a high frequency acoustic wave resonator according to an embodiment of the present invention.

FIG. 7 shows different SiO₂IHP-SAW (LiNbO) at layer thickness₃/SiO₂/Si) admittance-frequency response curve of the structure; wherein (a) is SiO₂The admittance-frequency response curve of IHP-SAW structure with the layer thickness of 550nm, and (b) SiO₂Admittance-frequency response curve of IHP-SAW structure with layer thickness of 1.1 μm: (c) Is SiO₂the admittance-frequency response curve of the IHP-SAW structure with a layer thickness of 2.2 μm, and (d) SiO₂Admittance-frequency response curve for IHP-SAW structure with layer thickness of 4.4 μm.

Fig. 8 shows admittance versus frequency response curves for a high frequency acoustic resonator provided in accordance with the present invention with a very low acoustic resistance component thickness of 4 μm.

FIG. 9 shows displacement amounts of mass points at a frequency point of 3100MHz in a depth direction of IHP-SAW and a high frequency acoustic resonator provided by the present invention; wherein, (a) is the displacement of each mass point of the IHP-SAW in the depth direction at a frequency point of 3100MHz, and (b) is the displacement of each mass point of the high-frequency acoustic wave resonator provided by the invention in the depth direction at a frequency point of 3100 MHz.

Description of the element reference numerals

1 extremely low acoustic resistance part

10 substrate

11 single-layer extremely low sound resistance material layer

2 piezoelectric film

3 patterned upper electrode

31 first fixing part

32 first finger

33 second fixed part

34 second finger

D, the distance between the first interdigital and the second fixed part

S1-S3

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1 to 8. It should be noted that the drawings provided in the present embodiment are only schematic and illustrate the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.