CN220273653U

CN220273653U - Resonator

Info

Publication number: CN220273653U
Application number: CN202322068015.9U
Authority: CN
Inventors: 蔡洵; 赖志国; 杨清华
Original assignee: Suzhou Huntersun Electronics Co Ltd
Current assignee: Suzhou Huntersun Electronics Co Ltd
Priority date: 2023-08-03
Filing date: 2023-08-03
Publication date: 2023-12-29
Anticipated expiration: 2033-08-03

Abstract

The utility model relates to a resonator, which comprises a substrate, a second electrode, a piezoelectric layer and a first electrode which are stacked; wherein, the substrate is provided with an acoustic wave reflecting area; the parts of the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode, which are overlapped on the projection of the upper surface of the substrate, form a resonance area; the projection of the layer with the smallest area among the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode forming the resonance area is polygonal, and at least one inner angle of the polygon is chamfered by an arc; the radius of the circular arc is smaller than half of the length of the largest side of the two adjacent sides.

Description

Resonator

Technical Field

The present utility model relates to the field of electronics, and more particularly to a resonator.

Background

In the prior art, the resonator is often applied to the communication field, along with the rapid development of the mobile communication technology, the performance requirement on the resonator is higher and higher, particularly, the performance of the thin film bulk acoustic resonator needs to be improved as a typical device of the resonator, but the problem of stress concentration exists in the resonance area of the conventional thin film bulk acoustic resonator (thin film BAW), particularly, when the resonator is applied to a high-power situation, the resonator often has serious transverse energy leakage and even failure due to the fact that the stress is too concentrated at the corner of a polygon, and the device performance is seriously affected.

Disclosure of Invention

The utility model aims at the technical problems, and designs a resonator and an electronic device, which can overcome the technical problems in the prior art, so that the transverse energy leakage of the resonator is reduced, the occurrence of failure is reduced, and the device performance of the resonator is improved.

The following presents a simplified summary of the utility model in order to provide a basic understanding of some aspects of the utility model. It should be understood that this summary is not an exhaustive overview of the utility model. It is not intended to identify key or critical elements of the utility model or to delineate the scope of the utility model. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

According to the utility model, a resonator is provided, which comprises a substrate, a second electrode, a piezoelectric layer and a first electrode which are stacked; wherein, the substrate is provided with an acoustic wave reflecting area; the parts of the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode, which are overlapped on the projection of the upper surface of the substrate, form a resonance area; the projection of the layer with the smallest area among the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode forming the resonance area is polygonal, and at least one inner angle of the polygon is chamfered by an arc; the radius of the circular arc is smaller than half of the length of the largest side of the two adjacent sides.

Further, the acoustic wave reflecting region includes one of a cavity, a Bragg reflection layer, or a back cavity.

Further, the polygon is a regular or irregular polygon.

Further, all inner corners of the polygon are chamfered by circular arcs.

Further, the layer with the smallest area is the sound wave reflection area, the piezoelectric layer, the first electrode or the second electrode.

Further, the projections of the acoustic wave reflecting area, the second electrode, the piezoelectric layer and the first electrode on the upper surface of the substrate are polygonal.

Further, at least one inner angle of each polygon projected on the upper surface of the substrate of the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode is chamfered by an arc.

Further, the radius of the arc is less than half the length of the largest of the two adjacent sides.

Further, all the inner corners except the edges connected with the external signal leads in the inner corners of the first electrode and/or the second electrode are chamfered by circular arcs.

Further, the arc is one section of arc or a plurality of sections of arc, and the plurality of sections of arc form an S shape or a wave shape.

The solution of the present disclosure can at least help to achieve one of the following effects: the manufacturing process is simple, the transverse energy leakage is reduced, the occurrence of failure is reduced, and the device performance of the resonator is improved.

Drawings

The above and other objects, features and advantages of the present utility model will be more readily appreciated by reference to the following detailed description of the utility model taken in conjunction with the accompanying drawings. The drawings are only for the purpose of illustrating the principles of the utility model. The dimensions and relative positioning of the elements in the figures are not necessarily drawn to scale.

Fig. 1 shows a schematic structural diagram of a resonator according to the utility model;

FIG. 2 shows another schematic structural diagram of the resonator of the present utility model;

FIG. 3 shows a schematic diagram of the shape of the resonance region of the prior art resonator and the resonator of the present utility model, (a) is a schematic diagram of the top electrode of the prior art, and (b) is a schematic diagram of the top electrode of the present utility model;

FIG. 4 is another top view of the upper electrode of the present utility model;

fig. 5 is a schematic top view of the upper electrode of the present utility model.

Detailed Description

An exemplary disclosure of the present utility model will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an implementation of the utility model are described in the specification. It will be appreciated, however, that in the development of any such actual implementation, numerous implementation-specific decisions may be made to achieve the developers' specific goals, and that these decisions may vary from one implementation to another.

In this case, in order to avoid obscuring the present utility model by unnecessary details, only the device structures closely related to the scheme according to the present utility model are shown in the drawings, and other details not greatly related to the present utility model are omitted.

In general, it should be understood that the drawings and the various elements depicted therein are not drawn to scale. Moreover, the use of relative terms (e.g., "above," "below," "top," "bottom," "upper," and "lower") to describe various elements' relationships to one another should be understood to encompass different orientations of the device and/or elements in addition to the orientation depicted in the figures.

It is to be understood that the utility model is not limited to the described embodiments, as a result of the following description with reference to the drawings. Herein, features between different embodiments may be replaced or borrowed, where possible, and one or more features may be omitted in one embodiment, where like reference numerals refer to like parts. It should be understood that the manufacturing steps of the present utility model are exemplary in embodiments, and that the order of the steps may be varied.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a thin film bulk acoustic resonator. As shown in fig. 1, the thin film bulk acoustic resonator includes at least a substrate 100, a cavity 101, a lower electrode 102, a piezoelectric layer 103, and an upper electrode 104. The cavity 101 serves as an acoustic wave reflection region, wherein the lower electrode 102, the upper electrode 104 and the piezoelectric layer 103 form a "sandwich" structure, which is first covered in the cavity 101 filled with the sacrificial material in the process of manufacturing the thin film bulk acoustic resonator, and the sacrificial material is removed after the subsequent manufacturing process is completed, so as to release the cavity 101. In filling the sacrificial material, the sacrificial material is typically conformally deposited on the upper surface of the substrate 100, and thus a planarization process, such as chemical mechanical polishing, is required on the upper surface of the substrate 100 to remove the sacrificial material outside of the cavity 101.

It is to be understood that the present utility model may also be configured to form the acoustic wave reflecting region using a bragg reflection layer without using the cavity 101, that is, to form a plurality of layers of films of different acoustic resistances stacked in the thickness direction of the first substrate 100 on the first substrate 100.

The substrate 100 may be, for example, high resistance silicon, gallium arsenide, indium phosphide, glass, sapphire, aluminum oxide _、 SiC, and the like, is formed of materials compatible with semiconductor processes. It should be noted in particular that when the substrate 100 is made of a glass material, its dielectric constant is low, and its resistance efficiency is high, which is more advantageous in high-frequency performance.

Further, referring to fig. 2, fig. 2 is another schematic structural diagram of a thin film bulk acoustic resonator formed by bulk silicon etching of the structure, i.e., by first performing a planarization process such as chemical mechanical polishing on the back surface of the substrate 100, and then etching a back cavity through the substrate from the back surface of the substrate 100 to serve as an acoustic wave reflection region of the thin film bulk acoustic resonator. Alternatively, instead of using a back cavity through the substrate 100, the thin film bulk acoustic resonator may be formed by first thinning the substrate 100, then etching the substrate 100 to form the back cavity, and then bonding a support substrate (not shown).

In an embodiment, the lower electrode 102 may be a single layer or a plurality of layers, and the lower electrode 102 is formed on the region of the acoustic reflection layer. The lower electrode 102 may be formed of one or more conductive materials, such as various metals compatible with semiconductor processes including tungsten, molybdenum, iridium, aluminum, platinum, ruthenium, niobium, or hafnium. The projected contour of the lower electrode 102 on the surface of the substrate 100 may be an irregular polygon or a regular polygon, such as a triangle, a rectangle, a pentagon, a hexagon, a heptagon, an octagon, etc., as examples.

The piezoelectric layer 103 is formed on the lower electrode 102, and the piezoelectric layer 103 may be formed of any piezoelectric material compatible with semiconductor processes, such as aluminum nitride, doped aluminum nitride, or titanate zirconate (PZT). The projected contour of the piezoelectric layer 103 on the surface of the substrate 100 may likewise be an irregular polygon or a regular polygon, such as, for example, a triangle, rectangle, pentagon, hexagon, heptagon, octagon, etc.

The upper electrode 104 is formed on the piezoelectric layer 103, and the upper electrode 104 may be formed of one or more conductive materials, for example, various metals compatible with semiconductor processes including tungsten, molybdenum, iridium, aluminum, platinum, ruthenium, niobium, or hafnium. The materials of the upper electrode 104 and the lower electrode 102 may be the same or different. The projected contour of the upper electrode 104 on the surface of the substrate 100 may be an irregular polygon or a regular polygon, such as a triangle, a rectangle, a pentagon, a hexagon, a heptagon, an octagon, etc., as examples.

Referring again to fig. 1, the portions of the acoustic wave reflecting region 101, the lower electrode 102, the piezoelectric layer 103, and the upper electrode 104 that overlap on the projection of the substrate constitute a resonance region. Illustratively, among the acoustic wave reflecting region, the lower electrode, the piezoelectric layer, and the upper electrode constituting the resonance region in fig. 1, one layer having the smallest area is the upper electrode 104.

It will be appreciated by those skilled in the art that when the acoustic wave reflecting region is a cavity or back cavity, the layer with the smallest area may also be the piezoelectric layer 103 or the acoustic wave reflecting region 101; when the acoustic wave reflecting region is a bragg reflecting layer, the layer having the smallest area may be the piezoelectric layer 103, the acoustic wave reflecting region 101, or the layer having the smallest area below the lower electrode layer 102, for example, the upper electrode 104.

Referring to fig. 3, fig. 3 (a) is a schematic top view of the upper electrode 104 in the prior art, and fig. 3 (b) is a schematic top view of the upper electrode 104 in the present utility model. The upper electrode 104 may be a polygon, and illustratively, the polygon may be a regular or irregular polygon. In fig. 3 (a), the interior corners 230 of the adjacent sides 220 of the pentagon are formed by the direct intersection of the line segments of the two sides. In this shape, the stress is concentrated near the vertex of the internal corner 230, and in the case of high power, the stress is too concentrated at the corner of the polygon, so that the thin film bulk acoustic resonator has serious lateral energy leakage, and even failure occurs, which seriously affects the device performance.

To solve this problem, referring to fig. 3 (b), the upper electrode 104 of the present utility model has a pentagon shape, at least one inner corner 210 formed by two adjacent sides 200 of which is chamfered with an arc tangent to at least one of the two adjacent sides 200. Preferably, the radius of the arc is less than half the length of the largest of the two adjacent sides 200, which minimizes stress concentrations. The circular arc chamfer can be realized by etching or rounding process (rounding process) in the semiconductor process.

In a variant embodiment of the utility model, all the internal corners 210 formed by the two adjacent sides 200 of the pentagon are chamfered with a circular arc tangent to the two adjacent sides 200. Preferably, the radius of the arc is less than half the length of the largest of the two adjacent sides 200.

Referring to fig. 4, fig. 4 is another schematic top view of the upper electrode 104 according to the present utility model. In another variant of the present utility model, when the upper electrode 104 is pentagonal, the edges 240 thereof are used for connection to external signal leads, and the inner corners formed by the edges 240 and the adjacent edges thereof may not be rounded, but all the inner corners are rounded with arcs.

It should be understood that, in the present utility model, although the schematic plan view of the upper electrode 104 is illustrated by an irregular pentagon, the plan view of the upper electrode 104 may be a regular pentagon, an irregular heptagon, or the like, which is not limited in the present utility model.

It will be appreciated that if the layer of smallest area is the piezoelectric layer 103 or the acoustic reflection region 101, at least one inner corner 210 of its adjacent sides 200 is rounded with a circular arc tangent to at least one of the two adjacent sides 200 if the piezoelectric layer 103 or the acoustic reflection region 101 is seen in top view as shown in fig. 3 (b). Preferably, all internal corners 210 formed by adjacent sides 200 of the pentagon are rounded with an arc, and more preferably, the radius of the arc of each rounded corner is less than half the length of the largest of the adjacent sides 200.

Further, when the top views of the resonant area components are polygonal, at least one inner angle formed by two adjacent sides of each component in the resonant area can be chamfered by an arc. Preferably, all the inner corners formed by the adjacent two sides of each assembly are rounded with circular arcs. More preferably, the radius of the arc of each chamfer is less than half the length of the largest of the two adjacent sides 200.

Referring to fig. 5, fig. 5 is a schematic top view of the upper electrode of the present utility model. It should be understood that the arc claimed in the present utility model may be one arc as shown in fig. 3b, or may be a plurality of arcs, which may be formed in an S-shape as shown in fig. 5. Further, the plurality of segments of circular arcs may be formed in a wave shape.

According to the utility model, the inner angles of the polygons forming the structure with the smallest area in the resonance region are chamfered by the circular arcs, so that the manufacturing process is simple, the transverse energy leakage of the resonator can be reduced, the stress is relieved, the failure condition of the resonator is reduced, and the device performance of the resonator is improved.

Another embodiment of the present utility model also provides an electronic device including the resonator of the present utility model.

The utility model has been described in connection with specific embodiments, but it will be apparent to those skilled in the art that these descriptions are intended to be illustrative and not limiting of the scope of the utility model. Various modifications and alterations of this utility model will occur to those skilled in the art in light of the spirit and principles of this utility model, and such modifications and alterations are also within the scope of this utility model.

Claims

1. A resonator, characterized by: the device comprises a substrate, a second electrode, a piezoelectric layer and a first electrode which are stacked;

an acoustic wave reflecting region is formed in the substrate;

the parts of the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode, which are overlapped on the projection of the upper surface of the substrate, form a resonance area;

the projection of the layer with the smallest area among the acoustic wave reflection area, the second electrode, the piezoelectric layer and the first electrode forming the resonance area is polygonal, and at least one inner angle of the polygon is chamfered by an arc;

the radius of the circular arc is smaller than half of the length of the largest side of the two adjacent sides.

2. A resonator as claimed in claim 1, characterized in that: the acoustic wave reflecting region includes one of a cavity, a Bragg reflecting layer, or a back cavity.

3. A resonator as claimed in claim 1, characterized in that: the polygon is a regular or irregular polygon.

4. A resonator as claimed in claim 3, characterized in that: all inner corners of the polygon are chamfered by circular arcs.

5. A resonator as claimed in claim 3, characterized in that: the layer with the smallest area is the sound wave reflection area, the piezoelectric layer, the first electrode or the second electrode.

6. A resonator as claimed in claim 3, characterized in that: the projections of the sound wave reflection area, the second electrode, the piezoelectric layer and the first electrode on the upper surface of the substrate are polygonal.

7. The resonator of claim 6, wherein: and at least one inner angle of each polygon projected on the upper surface of the substrate of the sound wave reflection area, the second electrode, the piezoelectric layer and the first electrode is chamfered by an arc.

8. The resonator of claim 7, wherein: the radius of the arc is less than half the length of the largest of the two adjacent sides.

9. The resonator of claim 7, wherein: all the inner corners except the edges connected with the external signal leads in the inner corners of the first electrode and/or the second electrode are chamfered by circular arcs.

10. A resonator as claimed in any one of claims 1 to 9, characterized in that: the arc is one section or multiple sections of arc, and the multiple sections of arc form an S shape or wave shape.