CN117318663A - A surface acoustic wave resonator and MEMS device that can improve insertion loss - Google Patents

Abstract

This application relates to the technical field of resonators, and discloses a surface acoustic wave resonator that can improve insertion loss, including: a piezoelectric substrate, used for acoustic and electrical energy conversion; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; The interdigital electrode structure excites acoustic and electrical transduction by applying voltage; the first temperature compensation layer wraps the interdigital electrode structure; a plurality of metal strips are arranged on the first temperature compensation layer; each metal strip is arranged on the interdigital electrode The electrodes of the structure refer to end regions, and at least some of the metal strips are of inconsistent length. In this way, by arranging metal strips with inconsistent lengths in the end areas of the electrode fingers of the interdigital electrode structure, different harmonics can be suppressed, thereby improving the insertion loss function of the surface acoustic wave resonator. This application also discloses a MEMS device.

Description

A surface acoustic wave resonator and MEMS device that can improve insertion loss

Technical field

This application relates to the field of resonator technology, for example, to a surface acoustic wave resonator and MEMS device that can improve insertion loss.

Background technique

Surface acoustic wave resonators are widely used due to their superior temperature stability. However, due to the influence of various harmonics, the insertion loss in the passband of the surface acoustic wave resonator will fluctuate a lot, and in severe cases, the insertion loss may even worsen. Therefore, how to improve the insertion loss function of surface acoustic wave resonators needs to be solved urgently.

Contents of the invention

In order to provide a basic understanding of some aspects of the disclosed embodiments, a simplified summary is provided below. This summary is not intended to be a general review, nor is it intended to identify key/important elements or delineate the scope of the embodiments, but is intended to serve as a prelude to the detailed description that follows.

Embodiments of the present invention provide a surface acoustic wave resonator and a MEMS device that can improve insertion loss, so as to improve the insertion loss function of the surface acoustic wave resonator.

In some embodiments, the surface acoustic wave resonator includes: a piezoelectric substrate for acoustic and electrical transduction; an interdigital electrode structure provided on the outer surface of the piezoelectric substrate; and the interdigital electrode structure is excited by applying a voltage. Acoustic and electrical transduction; a first temperature compensation layer, wrapping the interdigital electrode structure; a plurality of metal strips, arranged on the first temperature compensation layer; each metal strip is arranged in the electrode finger end area of the interdigitated electrode structure, and at least part of The lengths of the metal bars are inconsistent.

In some embodiments, the surface acoustic wave resonator further includes: a first passivation layer disposed on the metal strip and the first temperature compensation layer not covered by the metal strip.

In some embodiments, the surface acoustic wave resonator further includes: a second temperature compensation layer disposed on a side of the first passivation layer away from the metal strip.

In some embodiments, the first temperature compensation layer is provided with a first through hole; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole The hole is connected to the third through hole, exposing the bus bar of the interdigital electrode structure; the surface acoustic wave resonator also includes: a metal layer, and the metal layer is connected to the interdigital electrode through the first through hole, the second through hole and the third through hole. Structural bus bars.

In some embodiments, the surface acoustic wave resonator further includes: a second passivation layer disposed on the second temperature compensation layer and the metal layer.

In some embodiments, the length of the metal strip is obtained by calculating (n+1/2)×L to obtain the length of the metal strip; n is a positive integer; L is the sound wavelength corresponding to the harmonic frequency.

In some embodiments, the piezoelectric substrate is made of lithium niobate crystals, lithium tantalate crystals, aluminum nitride, zinc oxide, or piezoelectric ceramics.

In some embodiments, the metal strip is composed of one or more of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum.

In some embodiments, when the surface acoustic wave resonator has multiple harmonic frequencies, multiple second metal strip lengths are obtained by bringing the acoustic wavelength corresponding to each harmonic frequency into the formula n×L, as Put the sound wavelength corresponding to each harmonic frequency into the formula p×L to obtain the width of the metal strip. p is the set parameter, L is the sound wavelength corresponding to the harmonic frequency, and n is a positive integer.

In some embodiments, a MEMS device includes a surface acoustic wave resonator as described above.

In some embodiments, MEMS devices include liquid level sensors, oscillators, microphones, radio frequency switches, or filters.

Embodiments of the present invention provide a surface acoustic wave resonator and MEMS device that can improve insertion loss. The following technical effects can be achieved: by arranging a piezoelectric substrate for acoustic electric transduction, and arranging an interdigital electrode structure on the outer surface of the piezoelectric substrate that excites acoustic electric transduction by applying voltage. A first temperature compensation layer is provided to wrap the interdigital electrode structure. A plurality of metal strips are provided on the first temperature compensation layer, each metal strip is located in the electrode finger end area of the interdigital electrode structure, and the lengths of at least some of the metal strips are inconsistent. In this way, by arranging metal strips with inconsistent lengths in the end areas of the electrode fingers of the interdigital electrode structure, different harmonics can be suppressed, thereby improving the insertion loss function of the surface acoustic wave resonator.

The above general description and the following description are exemplary and explanatory only and are not intended to limit the application.

Description of drawings

One or more embodiments are exemplified by corresponding drawings. These exemplary descriptions and drawings do not constitute limitations to the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings are not limited to scale and in which:

Fig. 1 is a cross-sectional view of an existing surface acoustic wave filter along the α-α' cross-section line shown in Fig. 2 according to an embodiment of the present invention;

Figure 2 is a schematic diagram of the interdigital electrode structure and the distribution of multiple metal strips of an existing surface acoustic wave resonator provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the distribution of the interdigital electrode structure and multiple metal strips of a surface acoustic wave resonator provided by an embodiment of the present invention;

Figure 4 is a cross-sectional view of a surface acoustic wave filter provided by an embodiment of the present invention along the α-α' cross-section line shown in Figure 3;

FIG. 5 is a schematic diagram of the frequency response curve of a surface acoustic wave resonator provided by an embodiment of the present invention.

Reference signs:

1: Piezoelectric substrate; 2: Interdigital electrode; 3: Third passivation layer; 4: First temperature compensation layer; 5: First passivation layer; 6: Second temperature compensation layer; 7: Second passivation layer layer; 8: metal layer; 9: metal strip; 10: first bus bar; 11: second bus bar; 12: third bus bar; 13: first electrode finger; 14: second electrode finger; 15: The third electrode finger; 16: the fourth electrode finger.

Detailed ways

In order to understand the characteristics and technical content of the embodiments of the present invention in more detail, the implementation of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The attached drawings are for reference only and are not intended to limit the embodiments of the present invention. In the following technical description, for convenience of explanation, multiple details are provided to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may be practiced without these details. In other instances, well-known structures and devices may be shown simplified to simplify the drawings.

The terms "first", "second", etc. in the description and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data so used are interchangeable under appropriate circumstances for the purposes of the embodiments of the invention described herein. Furthermore, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

In the embodiment of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "back", etc. is based on the orientation or position shown in the drawings. Positional relationship. These terms are mainly used to better describe the embodiments of the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. Moreover, some of the above terms may also be used to express other meanings in addition to indicating orientation or positional relationships. For example, the term "upper" may also be used to express a certain dependence relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present invention can be understood according to specific circumstances.

In addition, the terms "setting", "connection" and "fixing" should be understood broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediary, or two devices, components or Internal connections between components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

Unless otherwise stated, the term "plurality" means two or more.

In the embodiment of the present invention, the character "/" indicates that the preceding and following objects are in an "or" relationship. For example, A/B means: A or B.

The term "and/or" is an association relationship describing objects, indicating that three relationships can exist. For example, A and/or B means: A or B, or A and B.

It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

In some embodiments, as shown in FIG. 1 and FIG. 2 , the following structure is usually used in the related art to improve the insertion loss function of the surface acoustic resonator. The outer surface of the piezoelectric substrate 1 is provided with an interdigital electrode structure. The interdigital electrode structure includes an interdigital electrode 2 and a third passivation layer 3 disposed on the interdigital electrode. A first temperature compensation layer 4 is provided on the interdigital electrode structure. The first temperature compensation layer 4 partially wraps the interdigital electrode structure. The first temperature compensation layer 4 is provided with a first through hole, and the first through hole exposes the interdigital electrode. Structural bus bars. Metal strips 9 are disposed on the first temperature compensation layer 4 . Each metal strip 9 is disposed in the electrode finger end region of the interdigital electrode structure, and the length of each metal strip 9 is equal to the width of the piezoelectric substrate 1 . A first passivation layer 5 is provided on the metal strip 9 and the first temperature compensation layer 4 not covered by the metal strip 9 . The first passivation layer 5 is provided with a third through hole, and the third through hole is connected with the first through hole to expose the bus bar of the interdigital electrode structure. A second temperature compensation layer 6 is provided on the side of the first passivation layer 5 away from the metal strip 9 . The second temperature compensation layer 6 is provided with a second through hole, and the first through hole, the second through hole and the third through hole are connected to expose the bus bar of the interdigital electrode structure. The metal layer 8 connects the bus bars of the interdigital electrode structure through the first through hole, the second through hole and the third through hole. A second passivation layer 7 is provided on the second temperature compensation layer 6 and the metal layer 8 .

The interdigital electrode structure includes a first bus bar 10 , a second bus bar 11 , a third bus bar 12 , a first electrode finger 13 , a second electrode finger 14 , a third electrode finger 15 and a fourth electrode finger 16 . The first bus bar 10, the second bus bar 11 and the third bus bar 12 are parallel to each other. The first electrode fingers 13 and the second electrode fingers 14 are alternately arranged in an interdigitated shape. The third electrode fingers 15 and the fourth electrode fingers 16 are alternately arranged in an interdigitated shape. Among them, the first electrode finger 13 is an electrode finger vertically connected to the first bus bar 10 . The fourth electrode finger 16 is an electrode finger vertically connected to the third bus bar 12 . The second electrode fingers 14 are electrode fingers arranged vertically on the side of the second bus bar 11 close to the first bus bar 10 . The third electrode finger 15 is an electrode finger arranged vertically on the side of the second bus bar 11 close to the third bus bar 12 . At this time, the electrode finger end regions are the first electrode finger end region, the second electrode finger end region, the third electrode finger end region and the fourth electrode finger end region. A metal strip of equal length is respectively provided in the first electrode finger end area, the second electrode finger end area, the third electrode finger end area and the fourth electrode finger end area. However, only by arranging a metal strip of equal length in the end area of the first electrode finger, the end area of the second electrode finger, the end area of the third electrode finger and the end area of the fourth electrode finger, the insertion loss function of the surface acoustic wave resonator is reduced. Still worse.

Embodiments of the present invention provide a surface acoustic wave resonator, including: a piezoelectric substrate, an interdigital electrode structure, a first temperature compensation layer and a plurality of metal strips. The piezoelectric substrate is used for acoustic and electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; the interdigital electrode structure is used to stimulate acoustic and electric transduction by applying voltage; the first temperature compensation layer wraps the interdigital electrodes. Electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged in the electrode finger end area of the interdigital electrode structure, and the lengths of at least some of the metal strips are inconsistent.

Using the surface acoustic wave resonator provided by the embodiment of the present disclosure, a piezoelectric substrate is provided for acoustic electric transduction, and an interdigital electrode structure is provided on the outer surface of the piezoelectric substrate to excite acoustic electric transduction by applying a voltage. . A first temperature compensation layer is provided to wrap the interdigital electrode structure. A plurality of metal strips are provided on the first temperature compensation layer, each metal strip is located in the end region of the electrode finger of the interdigital electrode structure, and the lengths of at least some of the metal strips are inconsistent. In this way, by arranging metal strips with inconsistent lengths in the end areas of the electrode fingers of the interdigital electrode structure, different harmonics can be suppressed, thereby improving the insertion loss function of the surface acoustic wave resonator.

In some embodiments, an interdigitated electrode structure includes a plurality of bus bars and electrode fingers vertically connected to the bus bars. The end area of the electrode finger is the area where the end of the electrode finger is located and the area in the electrode finger that is flush with the area where the end of the electrode is located. The area on the electrode finger between the end edge of the electrode finger and the preset edge of the electrode finger is regarded as the area where the end of the electrode finger is located. The preset edge of the electrode finger is a position where the vertical distance on the electrode finger and the end edge of the electrode finger maintain a preset length.

Optionally, the interdigital electrode structure includes: interdigital electrodes.

Optionally, the interdigital electrode structure includes: an interdigital electrode and a third passivation layer disposed on the interdigital electrode.

Optionally, the interdigital electrodes include: a first bus bar, a second bus bar, a third bus bar, a first electrode finger, a second electrode finger, a third electrode finger, and a fourth electrode finger. The first bus bar, the second bus bar and the third bus bar are parallel to each other. The first electrode fingers and the second electrode fingers are alternately arranged in an interdigital shape. The third electrode fingers and the fourth electrode fingers are alternately arranged in an interdigitated shape. Wherein, the first electrode finger is an electrode finger vertically connected to the first bus bar. The fourth electrode finger is an electrode finger vertically connected to the third bus bar. The second electrode fingers are electrode fingers arranged vertically on a side of the second bus bar close to the first bus bar. The third electrode finger is an electrode finger arranged vertically on a side of the second bus bar close to the third bus bar.

In some embodiments, as shown in FIG. 3 , FIG. 3 is a schematic diagram of the interdigital electrode structure of the surface acoustic wave resonator and the distribution of multiple metal strips. The interdigital electrode structure includes a first bus bar 10 , a second bus bar 11 , a third bus bar 12 , a first electrode finger 13 , a second electrode finger 14 , a third electrode finger 15 and a fourth electrode finger 16 . The first bus bar 10, the second bus bar 11 and the third bus bar 12 are parallel to each other. The first electrode fingers 13 and the second electrode fingers 14 are alternately arranged in an interdigitated shape. The third electrode fingers 15 and the fourth electrode fingers 16 are alternately arranged in an interdigitated shape. Among them, the first electrode finger 13 is an electrode finger vertically connected to the first bus bar 10 . The fourth electrode finger 16 is an electrode finger vertically connected to the third bus bar 12 . The second electrode fingers 14 are electrode fingers arranged vertically on the side of the second bus bar 11 close to the first bus bar 10 . The third electrode finger 15 is an electrode finger arranged vertically on the side of the second bus bar 11 close to the third bus bar 12 . At this time, the electrode finger end regions are the first electrode finger end region, the second electrode finger end region, the first electrode finger end region and the second electrode finger end region. The area of the first electrode finger 13 that is flush with the end of the second electrode finger 14 and the area of the end of the second electrode finger 14 are called the first electrode finger end area. The area of the second electrode finger 14 that is flush with the end of the first electrode finger 13 and the area of the end of the first electrode finger 13 are called the second electrode finger end area. The area of the third electrode finger 15 that is flush with the end of the fourth electrode finger 16 and the area of the end of the fourth electrode finger 16 are called the third electrode finger end area. The area of the fourth electrode finger 16 that is flush with the end of the third electrode finger 15 and the area of the end of the third electrode finger 15 are called the fourth electrode finger end area. Two metal strips 9 are provided in the end area of the first electrode finger, and the lengths of the two metal strips 9 are equal. Two metal strips 9 are provided in the end area of the second electrode finger, and the lengths of the two metal strips 9 are different. Two metal strips 9 are provided in the end area of the third electrode finger, and the lengths of the two metal strips 9 are equal. Two metal strips 9 are provided in the end area of the fourth electrode finger, and the lengths of the two metal strips 9 are different.

In some embodiments, the electrode finger end region includes a first electrode finger end region, a second electrode finger end region, a third electrode finger end region, and a fourth electrode finger end region. At least two metal strips are provided in the end area of the first electrode finger. At least two metal strips are provided in the end area of the second electrode finger. At least two metal strips are provided in the end area of the third electrode finger. At least two metal strips are provided in the end area of the fourth electrode finger.

Optionally, the interdigital electrode includes: a fourth bus bar, a fifth bus bar and a plurality of electrode fingers. The fourth bus bar and the fifth bus bar are parallel to each other. The vertically connected electrode fingers on the fourth bus bar are fifth electrode fingers; the vertically connected electrode fingers on the fifth bus bar are sixth electrode fingers. The fifth electrode fingers of the fourth bus bar and the sixth electrode fingers of the fifth bus bar are alternately arranged in an interdigitated shape.

Optionally, the surface acoustic wave resonator further includes: a first passivation layer disposed on the metal strip and the first temperature compensation layer not covered by the metal strip. In this way, providing the first passivation layer can better protect the metal strip.

Optionally, the surface acoustic wave resonator further includes: a second temperature compensation layer disposed on a side of the first passivation layer away from the metal strip.

Optionally, the first temperature compensation layer is provided with a first through hole; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole and The third through hole is connected, exposing the bus bar of the interdigital electrode structure; the surface acoustic wave resonator also includes: a metal layer, the metal layer is connected to the interdigital electrode structure through the first through hole, the second through hole and the third through hole. Bus bars.

Optionally, the surface acoustic wave resonator further includes: a second passivation layer disposed on the second temperature compensation layer and the metal layer.

In some embodiments, as shown in FIG. 4 , FIG. 4 is a cross-sectional view of the surface acoustic wave filter along the α-α’ cross-section line shown in FIG. 3 . As shown in Figure 4, the outer surface of the piezoelectric substrate 1 is provided with an interdigital electrode structure. The interdigital electrode structure includes an interdigital electrode 2 and a third passivation layer 3 provided on the interdigital electrode 2. The third passivation layer is provided with a fourth through hole, and the fourth through hole exposes the bus bar of the interdigital electrode. A first temperature compensation layer 4 is provided on the interdigital electrode structure. The first temperature compensation layer 4 wraps the interdigital electrode structure. The first temperature compensation layer 4 is provided with a first through hole, and the first through hole is connected to the fourth through hole. , exposing the bus bars of the interdigitated electrode structure. A plurality of metal strips 9 are disposed on the first temperature compensation layer 4 . Each metal strip 9 is disposed at the end region of the electrode finger of the interdigital electrode structure, and at least some of the metal strips 9 have different lengths. A first passivation layer 5 is provided on the metal strip 9 and the first temperature compensation layer 4 not covered by the metal strip 9 . The first passivation layer 5 is provided with a third through hole, and the third through hole is connected with the first through hole to expose the bus bar of the interdigital electrode structure. A second temperature compensation layer 6 is provided on the side of the first passivation layer 5 away from the metal strip 9 . The second temperature compensation layer 6 is provided with a second through hole, and the first through hole, the second through hole and the third through hole are connected to expose the bus bar of the interdigital electrode structure. The metal layer 8 connects the bus bars of the interdigital electrode structure through the first through hole, the second through hole and the third through hole. A second passivation layer 7 is provided on the second temperature compensation layer 6 and the metal layer 8 .

Optionally, the length of the metal strip is obtained in the following way: calculate (n+1/2)×L to obtain the length of the metal strip; n is a positive integer; L is the sound wavelength corresponding to the harmonic frequency.

In some embodiments, the length of the metal strip disposed at the end region of the electrode finger of the surface acoustic wave resonator belongs to the first length set. In the case where the surface acoustic wave resonator has multiple harmonic frequencies, multiple first metal strip lengths are obtained by bringing the acoustic wavelength corresponding to each harmonic frequency into the formula (n+1/2)×L. A set of multiple first metal strip lengths is used as a first length set.

In some embodiments, the length of the metal strip disposed in the end region of the electrode finger of the surface acoustic wave resonator belongs to the second length set, and the width of the metal strip disposed in the end region of the electrode finger of the surface acoustic wave resonator belongs to the width set. . In the case where the surface acoustic wave resonator has multiple harmonic frequencies, multiple second metal strip lengths are obtained by bringing the acoustic wavelength corresponding to each harmonic frequency into the formula n×L. A set of multiple second metal strip lengths is used as a second length set. By bringing the acoustic wavelength corresponding to each harmonic frequency into the formula p×L, multiple metal strip widths are obtained. The set of multiple metal strip widths is used as a width set, p is the set parameter, and p can range from 0.4 to 0.6.

Alternatively, the piezoelectric substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide or piezoelectric ceramics.

Optionally, the metal strip is composed of one or more of titanium, chromium, silver, copper, molybdenum, platinum, tungsten and aluminum.

Optionally, the metal layer is composed of one or more metals selected from titanium, chromium, silver, copper, molybdenum, platinum, tungsten and aluminum.

Optionally, the interdigital electrodes are composed of one or more metals selected from titanium, chromium, silver, copper, molybdenum, platinum, tungsten and aluminum.

Optionally, in the case where the surface acoustic wave resonator has multiple harmonic frequencies, multiple second metal strip lengths are obtained by bringing the acoustic wavelength corresponding to each harmonic frequency into the formula n×L. The sound wavelength corresponding to the harmonic frequency is brought into the formula p×L to obtain the width of the metal strip. p is the set parameter, L is the sound wavelength corresponding to the harmonic frequency, and n is a positive integer.

Optionally, the first temperature compensation layer is made of silicon dioxide.

Optionally, the second temperature compensation layer is made of silicon dioxide.

Optionally, the first passivation layer is made of silicon nitride.

Optionally, the second passivation layer is made of silicon nitride.

Optionally, the third passivation layer is made of silicon nitride.

In some embodiments, as shown in FIG. 5 , FIG. 5 is a schematic diagram of the frequency response curve of a surface acoustic wave resonator. As shown in Figure 5, curve A is the frequency response curve of the surface acoustic wave resonator of the present application, and its S parameter is S (5, 4). Curve B is the frequency response curve of a surface acoustic wave resonator other than that of this application, and its S parameter is S(2,1). When the frequency (Frequency) is 925MHz, the insertion loss (Insertion Loss) of curve A is equal to -1.7060dB, and the insertion loss of curve B is equal to -4.0993dB. At a frequency of 960MHz, the insertion loss of curve A is equal to -1.8121dB, and the insertion loss of curve B is equal to -1.8475dB. It can be seen from Figure 5 that the frequency response curve of the surface acoustic wave resonator of the present application is flatter than the frequency response curve of the surface acoustic wave resonator of the non-application. It can be seen that the insertion loss function of the surface acoustic wave resonator of the present application is better.

An embodiment of the present invention provides a MEMS device, including the above-mentioned surface acoustic wave resonator. A surface acoustic wave resonator includes: a piezoelectric substrate, an interdigital electrode structure, a first temperature compensation layer and a plurality of metal strips. The piezoelectric substrate is used for acoustic and electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure; the interdigital electrode structure is used to stimulate acoustic and electric transduction by applying voltage; the first temperature compensation layer wraps the interdigital electrodes. Electrode structure; a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged in the electrode finger end area of the interdigital electrode structure, and the lengths of at least some of the metal strips are inconsistent.

Using the MEMS device provided by the embodiment of the present disclosure, the MEMS device includes the above-mentioned surface acoustic wave resonator. And the surface acoustic wave resonator is provided with a piezoelectric substrate for acoustic electric transduction, and an interdigital electrode structure for exciting acoustic electric transduction by applying voltage is provided on the outer surface of the piezoelectric substrate; a first temperature compensation layer is provided to wrap an interdigital electrode structure; and a plurality of metal strips are provided on the first temperature compensation layer, each metal strip is located in the end area of the electrode finger of the interdigital electrode structure, and the lengths of at least some of the metal strips are inconsistent. In this way, by arranging metal strips with inconsistent lengths in the end areas of the electrode fingers of the interdigital electrode structure, different harmonics can be suppressed, thereby improving the insertion loss function of the surface acoustic wave resonator. thereby improving the acoustic performance of MEMS devices.

Optionally, MEMS (Micro-Electro-Mechanical System) devices include liquid level sensors, oscillators, microphones, radio frequency switches or filters, etc.

The foregoing description and drawings illustrate embodiments of the invention sufficiently to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples represent only possible variations. Unless explicitly required, individual components and features are optional and the order of operations may vary. Portions and features of some embodiments may be included in or substituted for those of other embodiments. Furthermore, the words used in this application are used only to describe the embodiments and not to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. . Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed items. In addition, when used in this application, the term "comprise" and its variations "comprises" and/or "comprising" etc. refer to stated features, integers, steps, operations, elements, and/or The presence of a component does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groupings of these. Without further limitation, an element defined by the statement "comprises a..." does not exclude the presence of additional identical elements in a process, method or apparatus including the stated element. In this article, each embodiment may focus on its differences from other embodiments, and the same and similar parts among various embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiment, then the relevant parts can be referred to the description of the method part.

Claims (10)

1. A surface acoustic wave resonator capable of enhancing insertion loss, comprising:

a piezoelectric substrate for acoustic-electric transduction; the outer surface of the piezoelectric substrate is provided with an interdigital electrode structure;

an interdigital electrode structure for exciting acoustic-electric transduction by applying a voltage;

a first temperature compensation layer wrapping the interdigital electrode structure;

a plurality of metal strips arranged on the first temperature compensation layer; each metal strip is arranged at the end area of the electrode finger of the interdigital electrode structure, and at least part of the metal strips are inconsistent in length.

2. The surface acoustic wave resonator according to claim 1, characterized in that the surface acoustic wave resonator further comprises:

and a first passivation layer disposed on the metal strip and the first temperature compensation layer uncovered by the metal strip.

3. The surface acoustic wave resonator according to claim 2, characterized in that the surface acoustic wave resonator further comprises:

the second temperature compensation layer is arranged on one side of the first passivation layer far away from the metal strip.

4. A surface acoustic wave resonator according to claim 3, characterized in that the first temperature compensation layer is provided with a first through hole; the second temperature compensation layer is provided with a second through hole; the first passivation layer is provided with a third through hole; the first through hole, the second through hole and the third through hole are communicated, and the bus bar of the interdigital electrode structure is exposed; the surface acoustic wave resonator further includes:

and the metal layer is connected with the bus bar of the interdigital electrode structure through the first through hole, the second through hole and the third through hole.

5. The surface acoustic wave resonator according to claim 4, characterized in that the surface acoustic wave resonator further comprises:

and the second passivation layer is arranged on the second temperature compensation layer and the metal layer.

6. The surface acoustic wave resonator according to any of claims 1 to 5, characterized in that the length of the metal strip is obtained by: calculating (n+1/2) x L to obtain the length of the metal strip; n is a positive integer; l is the acoustic wavelength corresponding to the harmonic frequency.

7. The surface acoustic wave resonator according to any one of claims 1 to 5, characterized in that the piezoelectric substrate is made of lithium niobate crystal, lithium tantalate crystal, aluminum nitride, zinc oxide, or piezoelectric ceramic, and the metal bar is made of one or more metals of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum.

8. The surface acoustic wave resonator according to any one of claims 1 to 5, wherein in the case where the surface acoustic wave resonator has a plurality of harmonic frequencies, a plurality of second metal bar lengths are obtained by bringing the acoustic wave lengths corresponding to the respective harmonic frequencies into a formula n×l, a metal bar width is obtained by bringing the acoustic wave lengths corresponding to the respective harmonic frequencies into a formula p×l, p is a set parameter, L is the acoustic wave length corresponding to the harmonic frequencies, and n is a positive integer.

9. A MEMS device comprising a surface acoustic wave resonator as claimed in any one of claims 1 to 8.

10. The MEMS device, as recited in claim 9, wherein the MEMS device comprises a liquid level sensor, an oscillator, a microphone, a radio frequency switch, or a filter.