Resonator and manufacturing method therefor

Abstract

The present application provides a resonator and a manufacturing method therefor. The resonator comprises a substrate, a first electrode layer, a first piezoelectric layer, a temperature compensation layer, a second piezoelectric layer, and a second electrode layer; the first electrode layer is located on one side of the substrate; the first piezoelectric layer is located on the side of the first electrode layer away from the substrate; the temperature compensation layer comprises a temperature compensation layer body and a second cavity; a first gap is formed between the orthographic projection of the temperature compensation layer body on the substrate and the orthographic projection of the second cavity on the substrate; the second piezoelectric layer is located on the side of the temperature compensation layer away from the first piezoelectric layer; a second gap is formed between the orthographic projection of the second piezoelectric layer on the substrate and the orthographic projection of the first piezoelectric layer on the substrate; the orthographic projection of the second gap on the substrate overlaps the orthographic projection of the second cavity on the substrate; and the second electrode layer is located on the side of the second piezoelectric layer away from the temperature compensation layer. By additionally providing the second cavity, the operation stability of the resonator is improved, and by forming the second gap, the manufacturing of the second cavity can be effectively ensured.

Description

A resonator and its fabrication method

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510371655.8, filed on March 26, 2025, entitled "A resonator and a method for fabricating the same", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of resonators, and more particularly to a resonator and its fabrication method. Background Technology

[0004] The rapid development of wireless communication technology and the increasing multifunctionality of communication terminals have placed higher performance demands on frequency devices operating in the radio frequency band. Compared to traditional dielectric ceramic filters and surface acoustic wave filters, resonators have significant advantages. Resonators possess high frequency, low loss, and low temperature drift characteristics, thus dominating most wireless communication applications. To further improve the operational stability of resonators, adjustments can be made to certain structural components.

[0005] Application content

[0006] This application provides a resonator and its fabrication method. By adding a cavity structure in the temperature compensation layer and reducing the fabrication difficulty of the cavity through structural adjustments, the working stability and reliability of the resonator are improved.

[0007] In a first aspect, this application provides a resonator, including a substrate, a first electrode layer, a first piezoelectric layer, a temperature compensation layer, a second piezoelectric layer, and a second electrode layer; the substrate includes a first cavity that penetrates a portion of the substrate; the first electrode layer is located on one side of the substrate; the first piezoelectric layer is located on the side of the first electrode layer away from the substrate; the temperature compensation layer includes a temperature compensation layer body and a second cavity, the temperature compensation layer being located on the side of the first piezoelectric layer away from the first electrode layer; the orthographic projection of the temperature compensation layer body onto the substrate is located near the center of the orthographic projection of the second cavity onto the substrate, and a first gap exists between the orthographic projection of the temperature compensation layer body onto the substrate and the orthographic projection of the second cavity onto the substrate; the second piezoelectric layer is located on the side of the temperature compensation layer away from the first piezoelectric layer; a second gap exists between the orthographic projection of the second piezoelectric layer onto the substrate and the orthographic projection of the first piezoelectric layer onto the substrate, and the orthographic projection of the second gap onto the substrate overlaps with the orthographic projection of the second cavity onto the substrate; the second electrode layer is located on the side of the second piezoelectric layer away from the temperature compensation layer.

[0008] Optionally, the first electrode layer includes a first electrode portion and a second electrode portion that are interconnected, wherein the orthographic projection of the first electrode portion onto the substrate at least partially overlaps with the orthographic projection of the first cavity, and the orthographic projection of the second electrode portion onto the substrate does not overlap with the orthographic projection of the first cavity.

[0009] Optionally, the second piezoelectric layer includes a first piezoelectric portion, a second piezoelectric portion, and a third piezoelectric portion. The first piezoelectric portion is located on the side of the first piezoelectric layer away from the first electrode layer, and the orthographic projection of the first piezoelectric portion onto the substrate does not overlap with the first cavity. The third piezoelectric portion is located on the side of the first piezoelectric layer away from the substrate, and the orthographic projection of the third piezoelectric portion onto the substrate does not overlap with the orthographic projection of the first electrode layer onto the substrate. The orthographic projection of the second piezoelectric portion onto the substrate overlaps with the first cavity. The second piezoelectric portion includes a first piezoelectric unit, a second piezoelectric unit, and a third piezoelectric unit. The first piezoelectric unit is located on the side of the second cavity away from the first electrode layer, the second piezoelectric unit is located on the side of the first piezoelectric layer away from the first electrode layer, and the third piezoelectric unit is located on the side of the temperature compensation layer body away from the first electrode layer. A second gap exists between the orthographic projection of the first piezoelectric portion onto the substrate and the orthographic projection of the second piezoelectric portion onto the substrate, and the orthographic projection of the second gap onto the substrate at least partially overlaps with the orthographic projection of the second cavity onto the substrate.

[0010] Optionally, the second electrode layer includes a third electrode portion and a fourth electrode portion connected to each other. The third electrode portion is located on the side of the second piezoelectric layer away from the first piezoelectric layer, and the orthographic projection of the third electrode portion onto the substrate overlaps with the orthographic projection of the first cavity onto the substrate. The fourth electrode portion is located on the side of the second piezoelectric layer away from the first piezoelectric layer, and the orthographic projection of the fourth electrode portion onto the substrate does not overlap with the orthographic projection of the first electrode layer onto the substrate, nor does it overlap with the orthographic projection of the first cavity onto the substrate. The orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate.

[0011] Optionally, the resonator further includes a top electrode structure located on the side of the second electrode layer away from the second piezoelectric layer. The orthographic projection of the top electrode structure onto the substrate at least partially overlaps with the orthographic projection of the second electrode layer onto the substrate, and the orthographic projection of the top electrode structure onto the substrate overlaps with the first cavity onto the substrate.

[0012] The top electrode structure includes a first top electrode layer and a second top electrode layer, wherein the first top electrode layer is located on the side of the second top electrode layer that is close to the second piezoelectric layer.

[0013] The first top electrode layer further includes a third cavity, which penetrates the first top electrode layer.

[0014] Optionally, the orthographic projection of the third cavity onto the substrate does not overlap with the orthographic projection of the second cavity onto the substrate.

[0015] Optionally, along the first direction, the length of the temperature compensation layer body is L1, the length of the second cavity is L2, and the length of the first gap is L2; ​​wherein, L3 / (L1+L2+L3)≤1%, L1>0, L2>0, and L3>0; wherein, the first direction is parallel to the plane where the substrate is located.

[0016] Optionally, the scandium doping ratio in the material of the first piezoelectric layer is n1, and the scandium doping ratio in the material of the second piezoelectric layer is n2; wherein, n1>n2, n2≥0.

[0017] Optionally, the second cavity surrounds at least a portion of the temperature compensation layer body.

[0018] Optionally, the temperature compensation layer further includes a fourth cavity, which is located on the side of the second cavity away from the temperature compensation layer body, and the fourth cavity is connected to the second cavity.

[0019] Optionally, the resonator further includes a seed layer located on the side of the first electrode layer near the substrate.

[0020] In a second aspect, this application provides a method for fabricating a resonator, used to fabricate the resonator described in any one of the first aspects, the method comprising:

[0021] A substrate is provided; the substrate is etched to form a first cavity, the first cavity penetrating a portion of the substrate; a first sacrificial unit is filled within the first cavity; a first electrode layer is provided, the first electrode layer being located on one side of the substrate; a first piezoelectric layer is provided, the first piezoelectric layer being located on the side of the first electrode layer away from the substrate; a temperature compensation layer is provided, the temperature compensation layer being located on the side of the first electrode layer away from the first electrode layer; the temperature compensation layer is etched to form a temperature compensation layer body and a second sacrificial unit; the orthographic projection of the temperature compensation layer body onto the substrate is located near the orthographic projection of the second sacrificial unit onto the substrate, close to the center of the first cavity, and the... A first gap exists between the orthographic projection of the temperature compensation layer body onto the substrate and the orthographic projection of the second sacrificial unit onto the substrate; a second piezoelectric layer is provided, the second piezoelectric layer is located on the side of the temperature compensation layer away from the first piezoelectric layer, a second gap exists between the orthographic projection of the second piezoelectric layer onto the substrate and the orthographic projection of the first piezoelectric layer onto the substrate, and the orthographic projection of the second gap onto the substrate overlaps with the orthographic projection of the second cavity onto the substrate; a second electrode layer is provided, the second electrode layer is located on the side of the second piezoelectric layer away from the temperature compensation layer; the second sacrificial unit is removed and a second cavity is formed; the first sacrificial unit is removed and a first cavity is formed.

[0022] Optionally, providing a first electrode layer includes: providing a first electrode film layer located on one side of the substrate; etching the first electrode film layer and fabricating the first electrode layer, the first electrode layer including a first electrode portion and a second electrode portion interconnected, the orthographic projection of the first electrode portion onto the substrate at least partially overlapping the orthographic projection of the first cavity, and the orthographic projection of the second electrode portion onto the substrate not overlapping the orthographic projection of the first cavity; providing a second piezoelectric layer includes: providing a second piezoelectric layer, the second piezoelectric layer including a first piezoelectric portion and a second piezoelectric portion. The first piezoelectric portion is located on the side of the first piezoelectric layer away from the first electrode layer, and the orthographic projection of the first piezoelectric portion onto the substrate at least partially overlaps with the orthographic projection of the second electrode portion onto the substrate; the third piezoelectric portion is located on the side of the first piezoelectric layer away from the substrate, and the orthographic projection of the third piezoelectric portion onto the substrate does not overlap with the orthographic projection of the first electrode layer onto the substrate; the second piezoelectric portion includes a first piezoelectric unit, a second piezoelectric unit, and a third piezoelectric unit, and the first piezoelectric unit is located on the side of the first piezoelectric layer away from the substrate. The second piezoelectric unit is located on the side of the temperature compensation layer body away from the first electrode portion, the second piezoelectric unit is located on the side of the first piezoelectric layer away from the first electrode portion, and the third piezoelectric unit is located on the side of the temperature compensation layer body away from the first electrode portion; a second gap exists between the orthographic projection of the first piezoelectric portion onto the substrate and the orthographic projection of the second piezoelectric portion onto the substrate, and the orthographic projection of the second gap onto the substrate at least partially overlaps with the orthographic projection of the second sacrificial unit onto the substrate; providing a second electrode layer includes: providing a second electrode layer, the second electrode layer including a third electrode portion and a fourth electrode portion connected to each other, the third electrode portion being located on the side of the second piezoelectric portion away from the first piezoelectric layer, the orthographic projection of the third electrode portion onto the substrate at least partially overlapping with the orthographic projection of the first electrode portion onto the substrate, the fourth electrode portion being located on the side of the third piezoelectric portion away from the first piezoelectric layer, and the orthographic projection of the fourth electrode portion onto the substrate not overlapping with the orthographic projection of the first electrode layer onto the substrate; wherein, the orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate.

[0023] Optionally, after providing the second electrode layer, the method further includes: providing a first top electrode film layer, the first top electrode film layer being located on the side of the second piezoelectric layer away from the first piezoelectric layer; etching the first top electrode film layer and forming a first top electrode layer and a third cavity, the third cavity penetrating the first top electrode layer; filling the third cavity with a third sacrificial unit; providing a second top electrode layer, the second top electrode layer being located on the side of the first top electrode layer away from the second piezoelectric layer; wherein the resonator further includes a top electrode structure, the top electrode structure being located on the side of the second electrode layer away from the second piezoelectric layer, the orthographic projection of the top electrode structure onto the substrate at least partially overlapping the orthographic projection of the second electrode layer onto the substrate, and the orthographic projection of the top electrode structure onto the substrate not overlapping the orthographic projection of the second electrode portion onto the substrate; removing the second sacrificial unit and forming the second cavity includes: removing the second sacrificial unit and forming the second cavity, and simultaneously removing the third sacrificial unit and forming the third cavity.

[0024] This application provides a resonator comprising a substrate, a first electrode layer, a first piezoelectric layer, a temperature compensation layer, a second piezoelectric layer, and a second electrode layer. The first electrode layer, first piezoelectric layer, temperature compensation layer, second piezoelectric layer, and second electrode layer are sequentially stacked on one side of the substrate. The temperature compensation layer includes a temperature compensation layer body and a second cavity. A first gap exists between the temperature compensation layer body and the second cavity along a direction perpendicular to the thickness of the substrate. The second piezoelectric layer is entirely located on the side of the film layer containing the temperature compensation layer away from the first piezoelectric layer, and a portion of the film layer is bonded to the first piezoelectric layer. A second gap exists between the orthographic projection of the first piezoelectric layer onto the substrate and the orthographic projection of the second piezoelectric layer onto the substrate. The orthographic projection of the second gap onto the substrate at least partially overlaps with the orthographic projection of the second cavity onto the substrate. This second gap exposes the second cavity, facilitating its fabrication. The orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate. This arrangement of the second electrode layer prevents obstruction of the second gap, thus ensuring the fabrication of the second cavity. By setting a second cavity, transverse wave leakage can be prevented, thereby improving the working stability and reliability of the resonator. At the same time, by controlling the temperature compensation layer, the second piezoelectric layer, and the second electrode layer, the fabrication of the second cavity can be made convenient and the manufacturing cost can be reduced. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 is a schematic diagram of the structure of the first type of resonator provided in the embodiment of this application;

[0027] Figure 2 is a schematic diagram of the structure of the second type of resonator provided in the embodiment of this application;

[0028] Figure 3 is a schematic diagram of the structure of the third type of resonator provided in the embodiment of this application;

[0029] Figure 4 is a schematic diagram of the structure of the fourth type of resonator provided in the embodiment of this application;

[0030] Figure 5 is a schematic diagram of the structure of the fifth type of resonator provided in the embodiment of this application;

[0031] Figure 6 is a schematic diagram of the sixth type of resonator provided in the embodiment of this application;

[0032] Figure 7 is a top view of a resonator structure according to an embodiment of this application;

[0033] Figure 8 is a flowchart illustrating the fabrication method of the first resonator provided in the embodiments of this application;

[0034] Figure 9 is a flowchart illustrating the fabrication method of the second resonator provided in an embodiment of this application;

[0035] Figure 10 is a schematic diagram of the process of fabricating the first resonator provided in the embodiment of this application;

[0036] Figure 11 is a flowchart illustrating the fabrication method of the third resonator provided in the embodiments of this application;

[0037] Figure 12 is a schematic diagram of the process of fabricating the second resonator provided in the embodiments of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be fully described below with reference to the accompanying drawings in the embodiments of this invention, through specific implementation methods. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort fall within the protection scope of this invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a system, product, or device comprising a series of units is not necessarily limited to those steps or units explicitly listed, but may include other units not explicitly listed or inherent to such products or devices.

[0040] Figure 1 is a schematic diagram of the structure of a first resonator provided in an embodiment of the present invention. Referring to Figure 1, an embodiment of the present invention provides a resonator 10, which includes a substrate 100, a first electrode layer 200, a first piezoelectric layer 300, a temperature compensation layer 400, a second piezoelectric layer 500, and a second electrode layer 600. The substrate 100 includes a first cavity 101, which penetrates a portion of the substrate 100. The first electrode layer 200 is located on one side of the substrate 100. The first piezoelectric layer 300 is located on the side of the first electrode layer 200 away from the substrate 100. The temperature compensation layer 400 includes a temperature compensation layer body 410 and a second cavity 420, and the temperature compensation layer 400 is located on the side of the first piezoelectric layer 300 away from the first electrode layer 200. The orthographic projection of the temperature compensation layer body 410 onto the substrate 100 is located near the orthographic projection of the second cavity 420 onto the substrate 100, which is close to the center of the first cavity 101. A first gap S1 exists between the orthographic projection of the temperature compensation layer body 410 onto the substrate 100 and the orthographic projection of the second cavity 420 onto the substrate 100. The second piezoelectric layer 500 is located on the side of the temperature compensation layer 400 away from the first piezoelectric layer 300. A second gap S2 exists between the orthographic projection of the second piezoelectric layer 500 onto the substrate 100 and the orthographic projection of the first piezoelectric layer 300 onto the substrate 100. The orthographic projection of the second gap S2 onto the substrate 100 overlaps with the orthographic projection of the second cavity 420 onto the substrate 100. The second electrode layer 600 is located on the side of the second piezoelectric layer 500 away from the temperature compensation layer 400.

[0041] Referring to Figure 1, the resonator 10 provided in this embodiment of the invention includes a substrate 100, on which a first cavity 101 is disposed. The first cavity 101 penetrates a portion of the substrate 100; in other words, the first cavity 101 does not penetrate the substrate 100. The first cavity 101 can be understood as a groove structure on the substrate 100. Specifically, the first cavity 101 can be understood as the resonant cavity in the resonator 10.

[0042] Further, referring to Figure 1, the resonator 10 includes a first electrode layer 200, a first piezoelectric layer 300, and a second electrode layer 600. The first electrode layer 200, the first piezoelectric layer 300, and the second electrode layer 600 can be considered as a resonant stack structure of the resonator 10, with the first electrode layer 200 acting as the bottom electrode, the first piezoelectric layer 300 as a piezoelectric layer, and the second electrode layer 600 as the top electrode. Each structure in the resonant stack structure can be fabricated layer by layer using a coating process. Furthermore, the resonator 10 also includes a temperature compensation layer 400. Adding a temperature compensation layer 400 to the resonator 10 can effectively reduce the temperature drift that may exist in the resonator 10, thereby ensuring the stability and reliability of signal transmission in the resonator 10. Specifically, the first electrode layer 200 is located on one side of the substrate 100, the first piezoelectric layer 300 is located on the side of the first electrode layer 200 away from the substrate 100, and the second electrode layer 600 is located on the side of the first piezoelectric layer 300 away from the first electrode layer 200.

[0043] Furthermore, referring to Figure 1, the resonator 10 also includes a temperature compensation layer 400, which is located on the side of the first piezoelectric layer 300 away from the first electrode layer 200. Specifically, the temperature compensation layer 400 includes a temperature compensation layer body 410 and a second cavity 420. The temperature compensation layer body 410 is used to reduce the temperature drift that may exist in the resonator 20. The second cavity 420 is set in the film layer where the temperature compensation layer body 410 is located, which can further avoid transverse wave leakage, thereby ensuring the overall signal transmission reliability of the resonator 10. Referring to Figure 1, the orthographic projection of the temperature compensation layer body 410 onto the substrate 100 is located close to the orthographic projection of the second cavity 420 onto the substrate 100, which is close to the center of the first cavity 101. This can be understood as the position of the temperature compensation layer body 410 being positioned so that its orthographic projection onto the substrate 100 is close to the center of the first cavity 101, while the second cavity 420 is set around the temperature compensation layer body 410. Furthermore, referring to Figure 1, a first gap S1 exists between the orthographic projection of the temperature compensation layer body 410 onto the substrate 100 and the orthographic projection of the second cavity 420 onto the substrate 100. This can be understood as the second cavity 420 and the temperature compensation layer body 410 being non-adherently disposed, with a gap between them. The fabrication process of the corresponding temperature compensation layer 400 can be as follows: the temperature compensation layer 400 is formed on one side of the first piezoelectric layer 300, and then the temperature compensation layer 400 is patterned and etched. A portion of the area retained by the patterned etching becomes the subsequent temperature compensation layer body 410, while the other portion can form the second cavity 420 through a subsequent removal process. The area between the two is removed during the patterned etching process, forming the first gap S1. Simultaneously, the second electrode layer 600 is located on the side of the temperature compensation layer 400 away from the first electrode layer 200.

[0044] Furthermore, referring to Figure 1, the resonator 10 also includes a second piezoelectric layer 500. The second piezoelectric layer 500 is located on the side of the temperature compensation layer 400 away from the first piezoelectric layer 300. It can also be understood that the first piezoelectric layer 300 and the second piezoelectric layer 500 can stack and protect the temperature compensation layer body 410. Therefore, the second electrode layer 600 is located on the side of the second piezoelectric layer 500 away from the temperature compensation layer 400.

[0045] Furthermore, a second gap S2 exists between the orthographic projection of the second piezoelectric layer 500 onto the substrate 100 and the orthographic projection of the first piezoelectric layer 200 onto the substrate 100. The orthographic projection of the second gap S2 onto the substrate 100 overlaps with the orthographic projection of the second cavity 420 onto the substrate 100. In other words, the orthographic projection of the second electrode layer 600 onto the substrate 100 does not overlap with the orthographic projection of the second gap S2 onto the substrate 100. That is, the second gap S2 was not covered or blocked during the fabrication of the second electrode layer 600. By exposing the second gap S2, the subsequent fabrication of the second cavity 420 is facilitated, thereby mitigating the leakage of transverse waves in the resonator 10 and ensuring the overall signal transmission reliability of the resonator 10.

[0046] Optionally, Figure 2 is a schematic diagram of the structure of the second type of resonator provided in the embodiment of the present invention, and Figure 3 is a schematic diagram of the structure of the third type of resonator provided in the embodiment of the present invention. Referring to Figures 2 and 3, by adding a first piezoelectric layer 300 and a second piezoelectric layer 500 to the upper and lower sides of the temperature compensation layer 400 respectively, compared with the prior art, increasing the number of piezoelectric layers while adding the temperature compensation layer 400 can also improve the overall signal transmission reliability of the resonator 10. Referring to Figure 3, the added temperature compensation layer 400 is not patterned and etched. The second piezoelectric portion 520 located on the first layer of the temperature compensation layer 400 can be patterned. That is, a protrusion structure (refer to 520a in Figure 3) is added to the side of the second piezoelectric portion 520 away from the substrate 100. The second electrode layer 600 subsequently fabricated will continue to transmit this protrusion structure. On the one hand, it can alleviate the leakage of transverse waves in the resonator 10, thereby ensuring the overall signal transmission reliability of the resonator 10. On the other hand, it can also reduce the alignment difficulty of different film layers in the fabrication process and simplify the fabrication process.

[0047] In summary, this embodiment of the invention provides a resonator in which the orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate. This arrangement prevents the second electrode layer from obstructing the second gap, thus ensuring the fabrication of the second cavity. By providing the second cavity, transverse wave leakage can be prevented, improving the resonator's operational stability and reliability. Furthermore, by controlling the temperature compensation layer, the second piezoelectric layer, and the second electrode layer, the fabrication of the second cavity can be made convenient, reducing manufacturing costs.

[0048] Optionally, continuing to refer to FIG1, the first electrode layer 200 includes a first electrode portion 210 and a second electrode portion 220 connected to each other. The orthographic projection of the first electrode portion 210 onto the substrate 100 at least partially overlaps with the orthographic projection of the first cavity 101, and the orthographic projection of the second electrode portion 220 onto the substrate 100 does not overlap with the orthographic projection of the first cavity 101.

[0049] Furthermore, the resonator 10 also includes a first electrode layer 200 located on one side of the substrate 100, wherein the first electrode layer 200 includes a first electrode portion 210 and a second electrode portion 220, and the first electrode portion 210 and the second electrode portion 220 are interconnected. Referring to FIG1, the orthographic projection of the first electrode portion 210 onto the substrate 100 at least partially overlaps with the orthographic projection of the first cavity 101, the orthographic projection of the second electrode portion 220 onto the substrate 100 does not overlap with the orthographic projection of the first cavity 101, and the temperature compensation layer 400 is located on the side of the first piezoelectric layer 300 away from the first electrode portion 210. In the fabrication of the first electrode layer 200, the corresponding metal film layer is set across the entire surface. By patterning and etching the first electrode layer 200, the remaining film structure consists of a first electrode portion 210 and a second electrode portion 220. The first electrode portion 210 is disposed corresponding to the first cavity 101 along the thickness direction of the substrate 100, while the second electrode portion 210 is offset from the first cavity 101 along the thickness direction of the substrate 100. It should be noted that the dashed lines in Figure 1 are used to divide the first electrode portion 210 and the second electrode portion 220; however, these dashed lines do not exist in the actual product.

[0050] Furthermore, referring to Figure 1, the resonator 10 also includes a first piezoelectric layer 300. The first piezoelectric layer 300 is located on the side of the first electrode layer 200 away from the substrate 100, and a portion of the first piezoelectric layer 300 is also bonded to the substrate 100. Specifically, the first piezoelectric layer 300 is also formed over its entire surface, while the first electrode layer 200 is fabricated by patterned etching. Therefore, the first piezoelectric layer 300 covers not only the area of ​​the first electrode layer 300 but also the area of ​​the first electrode layer 200 that has been etched away.

[0051] Optionally, continuing to refer to Figure 1, the second piezoelectric layer 500 includes a first piezoelectric portion 510, a second piezoelectric portion 520, and a third piezoelectric portion 530. The first piezoelectric portion 510 is located on the side of the first piezoelectric layer 300 away from the first electrode layer 200, and the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 does not overlap with the orthographic projection of the first cavity 101 onto the substrate 100. The third piezoelectric portion 530 is located on the side of the first piezoelectric layer 300 away from the substrate 100, and the orthographic projection of the third piezoelectric portion 530 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100. The orthographic projection of the second piezoelectric portion 520 onto the substrate 100 overlaps with the first cavity 101. The second piezoelectric portion 520 includes a first piezoelectric unit 521, a second piezoelectric unit 522, and a third piezoelectric unit 523. The first piezoelectric unit 521 is located on the side of the second cavity 420 away from the first electrode layer 200, the second piezoelectric unit 522 is located on the side of the first piezoelectric layer 300 away from the first electrode layer 200, and the third piezoelectric unit 523 is located on the side of the temperature compensation layer body 410 away from the first electrode layer 200. A second gap S2 exists between the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 and the orthographic projection of the second piezoelectric portion 520 onto the substrate 100. The orthographic projection of the second gap S2 onto the substrate 100 and the orthographic projection of the second cavity 420 onto the substrate 100 at least partially overlap.

[0052] Furthermore, referring to Figure 1, the resonator 10 also includes a second piezoelectric layer 500, which is fabricated on its entire surface after the temperature compensation layer body 410 is fabricated. Specifically, the second piezoelectric layer 500 includes a first piezoelectric portion 510, a second piezoelectric portion 520, and a third piezoelectric portion 530, wherein the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 at least partially overlaps with the orthographic projection of the second electrode portion 220 onto the substrate 100; the third piezoelectric portion 530 is located on the side of the first piezoelectric layer 300 away from the substrate 100, and the orthographic projection of the third piezoelectric portion 530 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100. The second piezoelectric layer 500 is located on the side of the temperature compensation layer 400 away from the substrate 100, and specifically includes a first piezoelectric unit 521, a second piezoelectric unit 522, and a third piezoelectric unit 523. Specifically, the first piezoelectric unit 521 is located on the side of the second cavity 420 away from the first electrode portion 210, the second piezoelectric unit 522 is located on the side of the first piezoelectric layer 300 away from the first electrode portion 210 (i.e., the orthographic projection of the second piezoelectric unit 522 onto the substrate 100 overlaps with the orthographic projection of the first gap S1 onto the substrate 100), and the third piezoelectric unit 523 is located on the side of the temperature compensation layer body 410 away from the first electrode portion 210. Furthermore, a second gap S2 exists between the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 and the orthographic projection of the second piezoelectric portion 520 onto the substrate 100. This can be understood as the first piezoelectric portion 510 and the second piezoelectric portion 520 not being in complete contact, with a certain gap present. The orthographic projection of the second gap S2 onto the substrate 100 at least partially overlaps with the orthographic projection of the second cavity 420 onto the substrate 100, meaning that at least a portion of the second cavity 420 can be exposed through the second gap S2. Thus, during the fabrication of the second cavity 420, the etching medium used to remove the material filling the second cavity 420 can enter the second cavity 420 through the second gap S2, thereby simplifying the fabrication method of the second cavity 420 and reducing the manufacturing cost of the resonator 10. Optionally, the size of the second gap S2 can be adaptively adjusted according to the etching medium to ensure that the etching medium can flow into the area where the second cavity 420 is located. Specifically, by depositing the second piezoelectric layer 500 on one side of the temperature compensation layer 400 after patterned etching, the second piezoelectric layer 500 can support the patterned structure of the temperature compensation layer 400. In other words, the morphology of the temperature compensation layer body 410, the second cavity region, and the first gap S1 formed by patterned etching is transferred to the second piezoelectric layer 500. The second piezoelectric layer 500 can be deposited according to the location of the second cavity and the position of the temperature compensation layer body 410, which can reduce the alignment accuracy during the fabrication of the second piezoelectric layer 500.It should be noted that the dashed lines in Figure 1 are used to divide the second voltage layer 500 at different locations, but the dashed lines do not exist in the actual product.

[0053] Optionally, continuing to refer to Figure 1, the second electrode layer 600 includes a third electrode portion 610 and a fourth electrode portion 620 connected to each other. The third electrode portion 630 is located on the side of the second piezoelectric layer 500 away from the first piezoelectric layer 300. The orthographic projection of the third electrode portion 610 onto the substrate 100 at least partially overlaps with the orthographic projection of the first cavity 101 onto the substrate 100. The fourth electrode portion 620 is located on the side of the second piezoelectric layer 500 away from the first piezoelectric layer 300. The orthographic projection of the fourth electrode portion 620 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100, nor does it overlap with the orthographic projection of the first cavity 101 onto the substrate 100. The orthographic projection of the second electrode layer 600 onto the substrate 100 does not overlap with the orthographic projection of the second gap S2 onto the substrate 100.

[0054] Furthermore, referring to Figure 1, the resonator 10 also includes a second electrode layer 600, which includes a third electrode portion 610 and a fourth electrode portion 620. The third electrode portion 630 is located on the side of the second piezoelectric portion 520 away from the first piezoelectric layer 300, and the orthographic projection of the third electrode portion 610 onto the substrate 100 at least partially overlaps with the orthographic projection of the first electrode portion 210 onto the substrate 100. The fourth electrode portion 620 is located on the side of the third piezoelectric portion 530 away from the first piezoelectric layer 300, and the orthographic projection of the fourth electrode portion 620 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100. Dashed lines in Figure 1 are used to divide the second electrode layer 600 at different locations; however, these dashed lines do not exist in the actual product.

[0055] In summary, this invention provides a resonator in which a second gap exists between the orthographic projection of the first piezoelectric portion onto the substrate and the orthographic projection of the second piezoelectric portion onto the substrate. The orthographic projection of the second gap onto the substrate at least partially overlaps with the orthographic projection of the second cavity onto the substrate. This second gap exposes the second cavity, facilitating its fabrication. Furthermore, the second electrode layer located on the side of the second piezoelectric layer away from the substrate includes a third electrode portion and a fourth electrode portion. The orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate. This arrangement of the second electrode layer prevents obstruction of the second gap, thus ensuring the fabrication of the second cavity. By providing the second cavity, transverse wave leakage can be prevented, improving the operational stability and reliability of the resonator. Simultaneously, by controlling the temperature compensation layer, the second piezoelectric layer, and the second electrode layer, the ease of fabrication of the second cavity can be ensured, reducing manufacturing costs.

[0056] Figure 4 is a schematic diagram of the structure of the fourth type of resonator provided in the embodiment of the present invention, and Figure 5 is a schematic diagram of the structure of the fifth type of resonator provided in the embodiment of the present invention. Referring to Figures 4 and 5, the resonator 10 further includes a top electrode structure 700, which is located on the side of the second electrode layer 600 away from the second piezoelectric layer 500. The orthogonal projection of the top electrode structure 700 onto the substrate 100 at least partially overlaps with the orthogonal projection of the second electrode layer 600 onto the substrate 100, and the orthogonal projection of the top electrode structure 700 onto the substrate 100 overlaps with the orthogonal projection of the first cavity 101 onto the substrate 100. The top electrode structure 700 includes a first top electrode layer 710 and a second top electrode layer 720, with the first top electrode layer 710 located on the side of the second top electrode layer 720 closer to the second piezoelectric layer 500. The first top electrode layer 710 further includes a third cavity 711, which penetrates the first top electrode layer 710.

[0057] Furthermore, referring to Figures 4 and 5, the resonator 10 may also include a top electrode structure 700, which is disposed on the side of the second electrode layer 600 away from the substrate 100. By providing the top electrode structure 700, the signal transmission effect of the resonator 10 can be improved, thereby ensuring the reliability of the resonator 10.

[0058] The top electrode structure 700 includes a first top electrode layer 710 and a second top electrode layer 720. The first top electrode layer 710 is closer to the second electrode layer 600 than the second top electrode layer 720, meaning the top electrode structure 700 is a stacked structure. Further, referring to Figures 4 and 5, the orthographic projection of the top electrode structure 700 onto the substrate 100 at least partially overlaps with the orthographic projection of the second electrode layer 600 onto the substrate 100, but does not overlap with the orthographic projection of the second electrode portion 220 onto the substrate 100. Therefore, the arrangement of the top electrode structure 700 can be guaranteed not to obstruct the second gap S2, thereby improving signal transmission performance without affecting the fabrication of the second cavity 420.

[0059] Specifically, referring to Figures 4 and 5, the first top electrode layer 710 is located on the side of the second electrode layer 600 away from the substrate 100, and a third cavity 711 is formed in the first top electrode layer 710, penetrating the first top electrode layer 710. Further, the second top electrode layer 720 covers the first top electrode layer 710, and a portion of it is directly bonded to the second electrode layer 600. In the fabrication of the top electrode structure 700, the first top electrode layer 710 is fabricated first. During the fabrication of the first top electrode layer 710, the position of the third cavity 711 is etched, and the corresponding sacrificial material is filled. Subsequently, the second top electrode layer 720 is fabricated to cover the first top electrode layer 710 and the third cavity 711, and the third cavity 711 is formed by etching the sacrificial material within the third cavity 711. Optionally, the second cavity 420 and the third cavity 711 can be fabricated simultaneously, that is, the medium to be etched in the second cavity 420 and the sacrificial material in the third cavity 711 can be etched simultaneously. The number of third cavities 711 in the resonator 10 can be adjusted adaptively according to actual needs, and this embodiment of the invention does not impose a specific limitation on this. Optionally, the material filling the second cavity 420 and the third cavity 711 can be silicon dioxide, etc. Optionally, referring to Figure 4, the orthographic projection of the third cavity 711 onto the substrate 100 and the orthographic projection of the second cavity 420 onto the substrate 100 can be either overlapping or non-overlapping, demonstrating the flexibility in the arrangement of the third cavity 711.

[0060] Furthermore, referring to Figure 5, the orthographic projection of the third cavity 711 onto the substrate 100 does not overlap with the orthographic projection of the second cavity 420 onto the substrate 100.

[0061] Furthermore, referring to Figure 5, the orthographic projection of the third cavity 711 onto the substrate 100 does not overlap with the orthographic projection of the second cavity 420 onto the substrate 100. In other words, the staggered arrangement of the third cavity 711 and the second cavity 420 avoids longitudinal overlap of the cavities, which would lead to structural instability of the resonator 10 at the cavities. Therefore, while avoiding transverse wave leakage of the resonator 10, the overall flatness of the resonator 10 structure can also be balanced.

[0062] Referring to Figure 1, along the first direction X1, the length of the temperature compensation layer body 410 is L1, the length of the second cavity 420 is L2, and the length of the first gap S1 is L3; wherein, L3 / (L1+L2+L3)≤1%, L1>0, L2>0, and L3>0; and the first direction is parallel to the plane of the substrate 100. Referring to Figure 1, along the first direction X1, the length of the temperature compensation layer body 410 is L1, the length of the second cavity 420 is L2, and the length of the first gap S1 is L2. The first direction X1 can be understood as the horizontal direction in Figure 1. The length relationship of the temperature compensation layer body 410, the second cavity 420, and the first gap S1 in the temperature compensation layer 200 is as follows: L3 / (L1+L2+L3)≤1%. This can be understood as the length of the first gap S1 being approximately 1% or less than 1% of the total length, which is beneficial for achieving miniaturization of the resonator 10. In the fabrication of the temperature compensation layer 400, a temperature compensation layer (unetched) is formed on one side of the first piezoelectric layer 300 and patterned etched thereon. The area removed is the first gap S1. The areas retained after this patterned etching are the areas where the temperature compensation layer body 410 and the second cavity 420 are located, respectively. The retained structure at the second cavity 420 is then removed to form the second cavity 420. The degree of patterning of the temperature compensation layer 400 can be reflected by limiting the ratio of the first gap S1 to the total length. It should be noted that, referring to Figure 1, the first gap S1, the temperature compensation layer body 410, and the second cavity 420 are compared by length, or they can be compared based on the actual occupied area. This embodiment of the invention does not impose specific limitations on this.

[0063] Referring to Figures 1 to 5, the scandium doping ratio in the material of the first piezoelectric layer 300 is n1, and the scandium doping ratio in the material of the second piezoelectric layer 500 is n2; where n1 > n2 and n2 ≥ 0.

[0064] Furthermore, referring to Figures 1 to 5, the scandium content in the first piezoelectric layer 300 is n1, and the scandium content in the second piezoelectric layer 500 is n2, where n1 > n2, for example, 0 < n1 < 60%, and n2 = 0. That is, the scandium content in the first piezoelectric layer 300 is greater than the scandium content in the second piezoelectric layer 500. By differentiating the first piezoelectric layer 300 and the second piezoelectric layer 500 on the upper and lower sides of the temperature compensation layer 400, it is beneficial for the medium originally present in the second cavity 420 to be released through the second gap S2, thereby facilitating the formation of the second cavity 420. Optionally, the material of the first piezoelectric layer 300 may also include nitrogen and aluminum, and the material of the second piezoelectric layer 500 may also include nitrogen and aluminum. Furthermore, by adjusting the doping amount of nitrogen and aluminum in the second piezoelectric layer 500, a more stable foundation can be provided for the deposition and preparation of the second electrode layer 600, which is beneficial to improving the overall structural stability of the resonator 10. The doping amounts of nitrogen and aluminum can also be adjusted adaptively according to requirements, and the embodiments of the present invention do not impose specific limitations on this.

[0065] Figure 6 is a structural schematic diagram of the sixth type of resonator provided in the embodiment of the present invention, and Figure 7 is a top view schematic diagram of a resonator in an embodiment of the present invention. Referring to Figures 6 and 7, the second cavity 420 surrounds at least part of the temperature compensation layer body 410.

[0066] Furthermore, referring to Figures 1 to 5, 6, and 7, the second cavity 420 can be configured around the temperature compensation layer body 410. For example, as shown in the top view of Figure 7, the second cavity 420 can entirely surround the temperature compensation layer body 410; the second cavity 420 can also partially surround the temperature compensation layer body 410. There are various ways to configure the second cavity 420. Adjusting the cavity structure around the temperature compensation layer body 410, such as adjusting the number or size, can adjust the operating frequency of the resonator 10. The specific configuration of the cavity on one side of the temperature compensation layer body 410 can be adaptively adjusted according to actual needs, and this embodiment of the invention does not limit this.

[0067] Referring to Figures 6 and 7, the temperature compensation layer 400 further includes a fourth cavity 430, which is located on the side of the second cavity 420 away from the temperature compensation layer body 410, and the fourth cavity 430 is connected to the second cavity 420.

[0068] Specifically, referring to Figures 6 and 7, the temperature compensation layer 400 may further include a fourth cavity 430, which is located on the side of the second cavity 420 away from the temperature compensation layer body 410. By adding the fourth cavity 420, the operating frequency of the resonator 10 can be adjusted, making the resonator 10 more practical.

[0069] Furthermore, referring to Figure 7, the fourth cavity 430 is connected to the second cavity 420. The connection method between the fourth cavity 430 and the second cavity 420 can be adjusted according to actual needs. In Figure 7, the fourth cavity 430 and the second cavity 420 are connected at region A. Specifically, during the fabrication of the temperature compensation layer 400, the temperature compensation layer body 410, the second cavity setting region, and the fourth cavity setting region are retained after patterned etching. The material in the second cavity setting region and the material in the fourth cavity setting region are removed through the second gap S2 after the second electrode layer 600 is fabricated, thereby realizing the fabrication of the second cavity 420 and the fourth cavity 440. Therefore, the fourth cavity 430 needs to be connected to the second cavity 420. There are various ways to connect the fourth cavity 430 and the second cavity 420, which are not shown one by one in this embodiment of the invention.

[0070] Referring to Figures 1 to 6, the resonator 10 also includes a seed layer 800, which is located on the side of the first electrode layer 200 near the substrate 100.

[0071] Specifically, referring to Figures 1 to 6, a seed layer 800 is also provided in the resonator 10. The seed layer 800 can ensure the coating quality of the subsequently prepared electrode layer and piezoelectric layer. For example, the seed layer 800 includes a single-crystal aluminum nitride seed layer, and can be prepared by metal-organic chemical vapor deposition. The embodiments of the present invention do not specifically limit the specific material and preparation process of the seed layer structure.

[0072] Based on the same inventive concept, embodiments of the present invention also provide a method for fabricating a resonator. Figure 8 is a flowchart illustrating the first method for fabricating a resonator provided by an embodiment of the present invention, and Figure 9 is a process diagram illustrating the first method for fabricating a resonator provided by an embodiment of the present invention. Referring to Figures 8 and 9, the fabrication method includes:

[0073] S110 provides a substrate.

[0074] S120, etching the substrate and preparing the first cavity.

[0075] Specifically, a groove is designed on the substrate to fabricate the first cavity. The first cavity does not penetrate the substrate. Optionally, the fabrication of the first cavity on the substrate can be achieved using dry etching or wet etching, and the specific fabrication method can be adapted to meet specific requirements.

[0076] S130. Fill the first cavity with a first sacrificial unit. Specifically, filling the first cavity with a first sacrificial unit ensures that the surfaces of the substrate in the area where the first cavity is located and the area where the first cavity is not located are flush, which is beneficial for subsequent film layers such as seed layers and ensures a more stable resonator structure. S140. Provide a first electrode layer. S150. Provide a first piezoelectric layer.

[0077] Further, referring to Figure 1, the resonator 10 includes a first electrode layer 200, a first piezoelectric layer 300, and a second electrode layer 600. The first electrode layer 200, the first piezoelectric layer 300, and the second electrode layer 600 can be considered as a resonant stacked structure of the resonator 10. The first electrode layer 200 is equivalent to the bottom electrode, the first piezoelectric layer 300 is a piezoelectric layer, and the second electrode layer 600 is equivalent to the top electrode. Each structure in the resonant stacked structure can be fabricated layer by layer using a coating process. Specifically, the first electrode layer and the first piezoelectric layer are fabricated sequentially. The first electrode layer is located on one side of the substrate, the first piezoelectric layer is located on the side of the first electrode layer away from the substrate, and the second electrode layer is located on the side of the first piezoelectric layer away from the first electrode layer.

[0078] S160, Provide a temperature compensation layer. S170, Etch the temperature compensation layer and fabricate the temperature compensation layer body and the second sacrificial unit.

[0079] Furthermore, a temperature compensation layer is fabricated, located on the side of the first piezoelectric layer away from the first electrode layer. Specifically, the temperature compensation layer is patterned and etched, comprising a temperature compensation layer body and a second sacrificial unit. The temperature compensation layer body is used to reduce the temperature drift that may exist in the resonator. A second cavity is formed in the film layer containing the temperature compensation layer body, i.e., the second cavity is formed by removing the second sacrificial unit, which can further prevent transverse wave leakage and thus ensure the overall signal transmission reliability of the resonator. The orthogonal projection of the temperature compensation layer body onto the substrate is located near the orthogonal projection of the second sacrificial unit onto the substrate, close to the center of the first cavity. This can be understood as the orthogonal projection of the temperature compensation layer body onto the substrate being relatively close to the center of the first cavity, while the second sacrificial unit is arranged around the temperature compensation layer body. Furthermore, a first gap exists between the orthogonal projection of the temperature compensation layer body onto the substrate and the orthogonal projection of the second sacrificial unit onto the substrate. This can be understood as the second sacrificial unit and the temperature compensation layer body being non-adherently arranged, with a gap between them. The fabrication process of the corresponding temperature compensation layer can be understood as follows: A temperature compensation layer is formed on one side of the first piezoelectric layer, and then the temperature compensation layer is patterned and etched. Part of the area retained by the patterned etching becomes the subsequent temperature compensation layer body, and the other part becomes the second sacrificial unit. A second cavity can be formed through subsequent removal processes, while the area between the two is removed during the patterned etching process, forming the first gap. Simultaneously, the second electrode layer is located on the side of the temperature compensation layer away from the first electrode layer.

[0080] S180. A second piezoelectric layer is provided. Further, the second piezoelectric layer is located on the side of the temperature compensation layer away from the first piezoelectric layer; this can also be understood as the first and second piezoelectric layers stacking and protecting the temperature compensation layer body. Therefore, the second electrode layer is located on the side of the second piezoelectric layer away from the temperature compensation layer.

[0081] Furthermore, there is a second gap between the orthographic projection of the second piezoelectric layer onto the substrate and the orthographic projection of the first piezoelectric layer onto the substrate, and the orthographic projection of the second gap onto the substrate overlaps with the orthographic projection of the second cavity onto the substrate. In other words, the orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate. That is, the second gap was not covered or blocked during the fabrication of the second electrode layer. By exposing the second gap, it is easier to fabricate the second cavity subsequently, thereby mitigating the leakage of transverse waves in the resonator and ensuring the overall signal transmission reliability of the resonator.

[0082] S190, Provide a second electrode layer. S110, Remove the second sacrificial unit and prepare a second cavity.

[0083] Specifically, the second sacrificial unit can be removed through the reserved second gap, thereby forming the second cavity.

[0084] S1110. Remove the first sacrificial unit and prepare the first cavity. Specifically, the first cavity is prepared by removing the first sacrificial unit. The first cavity can be understood as the resonant cavity in a resonator.

[0085] In summary, the embodiments of the present invention provide a method for fabricating a resonator. By setting a second cavity, transverse wave leakage can be prevented, thereby improving the working stability and reliability of the resonator. At the same time, by controlling the temperature compensation layer, the second piezoelectric layer and the second electrode layer, the fabrication of the second cavity can be made convenient and the manufacturing cost can be reduced.

[0086] Figure 9 is a flowchart illustrating the second resonator fabrication method provided in an embodiment of the present invention, and Figure 10 is a flowchart illustrating the first resonator fabrication method provided in an embodiment of the present invention. Referring to Figures 9 and 10, the fabrication method includes:

[0087] S210. Provide a substrate. Specifically, referring to step a in FIG10, provide a substrate 100. S220. Etch the substrate and prepare a first cavity. Specifically, referring to step b in FIG10. S230. Fill the first cavity with a first sacrificial cell. Specifically, referring to steps c and d in FIG10. S240. Provide a first electrode film. Specifically, referring to step e in FIG10, prepare a first electrode film 200a on one side of the substrate 100. In FIG10, the first electrode layer 200 is located on the side of the seed layer 800 away from the substrate 100. S250. Etch the first electrode film and prepare a first electrode layer. Specifically, referring to step f in FIG10, prepare a first electrode layer 200 by etching the first electrode film, wherein the first electrode layer 200 includes a first electrode portion 210 and a second electrode portion 220, and the first electrode portion 210 and the second electrode portion 220 are interconnected. The orthographic projection of the first electrode portion 210 onto the substrate 100 at least partially overlaps with the orthographic projection of the first cavity 101, while the orthographic projection of the second electrode portion 220 onto the substrate 100 does not overlap with the orthographic projection of the first cavity 101. In the fabrication of the first electrode layer 200, the corresponding metal film layer is set across the entire surface. By patterning and etching the first electrode layer 200, the retained film structure consists of the first electrode portion 210 and the second electrode portion 220. The first electrode portion 210 is positioned corresponding to the first cavity 101 along the thickness direction of the substrate 100, while the second electrode portion 210 is offset from the first cavity 101 along the thickness direction of the substrate 100. It should be noted that the dashed lines in the figure are used to divide the first electrode portion 210 and the second electrode portion 220; however, these dashed lines do not exist in the actual product. S260, Provide a first piezoelectric layer. Specifically, referring to step g in Figure 10, prepare a first piezoelectric layer 300. The first piezoelectric layer 300 is located on the side of the first electrode layer 200 away from the substrate 100, and a portion of the first piezoelectric layer 300 is also bonded to the substrate 100. Specifically, the first piezoelectric layer 300 is also formed over its entire surface, while the first electrode layer 200 is patterned and etched. Therefore, the first piezoelectric layer 300 covers not only the area of ​​the first electrode layer 300 but also the area of ​​the first electrode layer 200 that has been etched away. S270, Provide a temperature compensation layer. Specifically, referring to step h in FIG10, a temperature compensation layer 400 is formed on the side of the first piezoelectric layer 300 away from the first electrode portion 210. By providing the temperature compensation layer 400, the temperature drift of the resonator can be reduced, thereby ensuring the stability and reliability of signal transmission in the resonator. S280, Etch the temperature compensation layer and form the temperature compensation layer body and the second sacrificial unit. Specifically, referring to step i in FIG10, the temperature compensation layer body 410 and the second sacrificial unit 421 are formed by etching the temperature compensation layer.The temperature compensation layer 400 includes a temperature compensation layer body 410 and a second sacrificial unit 421. The temperature compensation layer body 410 is used to reduce the temperature drift that may exist in the resonator 20. The second sacrificial unit 421 subsequently forms a second cavity. The setting of the second cavity in the film layer where the temperature compensation layer body 410 is located can further avoid transverse wave leakage, thereby ensuring the overall signal transmission reliability of the resonator 10. The orthogonal projection of the temperature compensation layer body 410 onto the substrate 100 is located near the orthogonal projection of the second sacrificial unit 421 onto the substrate 100, close to the center of the first cavity 101. This can be understood as the orthogonal projection of the temperature compensation layer body 410 onto the substrate 100 being close to the center of the first cavity 101, while the second sacrificial unit 421 is set around the temperature compensation layer body 410. Furthermore, a first gap S1 exists between the orthographic projection of the temperature compensation layer body 410 onto the substrate 100 and the orthographic projection of the second sacrificial unit 421 onto the substrate 100. This can be understood as the second sacrificial unit 421 and the temperature compensation layer body 410 being non-adherently disposed, with a gap between them. The fabrication process of the corresponding temperature compensation layer 400 can be as follows: a temperature compensation layer 400 is formed on one side of the first piezoelectric layer 300, and then the temperature compensation layer 400 is patterned and etched. Part of the area retained by the patterned etching is the subsequent temperature compensation layer body 410, and the other part is the second sacrificial unit 421. The second sacrificial unit 421 can form a second cavity 420 through a subsequent removal process, while the area between the two is removed during the patterned etching process, forming the first gap S1. It should be noted that the material of the second sacrificial unit 421 is the same as the material of the temperature compensation layer body 410.

[0088] S290. Provide a second piezoelectric layer. Specifically, referring to step j in FIG10, the second piezoelectric layer 500 is fabricated on its entire surface after the patterned temperature compensation layer 400. Specifically, the second piezoelectric layer 500 includes a first piezoelectric portion 510, a second piezoelectric portion 520, and a third piezoelectric portion 530, wherein the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 at least partially overlaps with the orthographic projection of the second electrode portion 220 onto the substrate 100; the third piezoelectric portion 530 is located on the side of the first piezoelectric layer 300 away from the substrate 100, and the orthographic projection of the third piezoelectric portion 530 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100. The second piezoelectric layer 500 is located on the side of the temperature compensation layer 400 away from the substrate 100, and specifically the second piezoelectric layer 500 includes a first piezoelectric unit 521, a second piezoelectric unit 522, and a third piezoelectric unit 523, which can also be referred to FIG1. Specifically, the first piezoelectric unit 521 is located on the side of the second sacrificial unit 421 away from the first electrode portion 210, the second piezoelectric unit 522 is located on the side of the first piezoelectric layer 300 away from the first electrode portion 210 (i.e., the orthographic projection of the second piezoelectric unit 522 onto the substrate 100 overlaps with the orthographic projection of the first gap S1 onto the substrate 100), and the third piezoelectric unit 523 is located on the side of the temperature compensation layer body 410 away from the first electrode portion 210. Furthermore, a second gap S2 exists between the orthographic projection of the first piezoelectric portion 510 onto the substrate 100 and the orthographic projection of the second piezoelectric portion 520 onto the substrate 100. This can be understood as the first piezoelectric portion 510 and the second piezoelectric portion 520 not being in complete contact, with a certain gap present. The orthographic projection of the second gap S2 onto the substrate 100 at least partially overlaps with the orthographic projection of the second sacrificial unit 421 onto the substrate 100, meaning that at least a portion of the second sacrificial unit 421 can be exposed through the second gap S2. Thus, the second sacrificial unit 421 can be removed by entering the second cavity 420 through the second gap S2, thereby simplifying the fabrication method of the second cavity 420 and reducing the manufacturing cost of the resonator 10. Optionally, the size of the second gap S2 can be adaptively adjusted according to the etching medium to ensure that the etching medium can flow into the area where the second cavity 420 is located. Specifically, by depositing the second piezoelectric layer 500 on one side of the temperature compensation layer 400 after patterned etching, the second piezoelectric layer 500 can support the patterned structure of the temperature compensation layer 400. In other words, the morphology of the temperature compensation layer body 410, the second sacrificial unit 421, and the first gap S1 formed by patterned etching is transferred to the second piezoelectric layer 500. The second piezoelectric layer 500 can be deposited according to the area where the second sacrificial unit 421 is located and the position of the temperature compensation layer body 410, which can reduce the alignment accuracy during the fabrication of the second piezoelectric layer 500. S2100, Provide the second electrode layer.Specifically, referring to step k in Figure 10, a second electrode layer 600 is provided. The second electrode layer 600 includes a third electrode portion 610 and a fourth electrode portion 620. The third electrode portion 630 is located on the side of the second piezoelectric portion 520 away from the first piezoelectric layer 300, and the orthographic projection of the third electrode portion 610 onto the substrate 100 at least partially overlaps with the orthographic projection of the first electrode portion 210 onto the substrate 100. The fourth electrode portion 620 is located on the side of the third piezoelectric portion 530 away from the first piezoelectric layer 300, and the orthographic projection of the fourth electrode portion 620 onto the substrate 100 does not overlap with the orthographic projection of the first electrode layer 200 onto the substrate 100. In this structure, the first electrode layer 200, the first piezoelectric layer 300, the second piezoelectric layer 500, and the second electrode layer 600 can be considered as the resonant stack structure of the resonator 10. The first electrode layer 200 is equivalent to the bottom electrode, the first piezoelectric layer 300 and the second piezoelectric layer 500 are piezoelectric layers, and the second electrode layer 600 is equivalent to the top electrode. Furthermore, each structure in the resonant stack structure can be fabricated layer by layer using a coating process. Further, the orthographic projection of the second electrode layer 600 onto the substrate 100 does not overlap with the orthographic projection of the second gap S2 onto the substrate 100. That is, the second gap S2 is not covered or blocked during the fabrication of the second electrode layer 600. By exposing the second gap S2, the subsequent fabrication of the second cavity 420 is facilitated, thereby mitigating the leakage of transverse waves in the resonator 10 and ensuring the overall signal transmission reliability of the resonator 10. S2110: Remove the second sacrificial unit and fabricate the second cavity. Specifically, referring to step 1 in Figure 10, the reserved second gap S2 is used, as shown by the arrow. The second sacrificial unit 421 can be removed through the second gap S2 to form the second cavity 420. S2120: Remove the first sacrificial unit and prepare the first cavity. Specifically, referring to step m in Figure 10, the first cavity 101 is prepared by removing the first sacrificial unit. The first cavity 101 can be understood as the resonant cavity in the resonator 10.

[0089] Optionally, Figure 11 is a flowchart illustrating the fabrication method of the third resonator provided in an embodiment of the present invention, and Figure 12 is a flowchart illustrating the fabrication method of the second resonator provided in an embodiment of the present invention. Referring to Figures 11 and 12, the fabrication method further includes: S310, providing a substrate. Specifically, referring to step a in Figure 12. S320, etching the substrate and fabricating a first cavity. Specifically, referring to step b in Figure 12. S330, filling the first cavity with a first sacrificial unit. Specifically, referring to steps c and d in Figure 12. S340, providing a first electrode film layer. Specifically, referring to step e in Figure 12. S350, etching the first electrode film layer and fabricating a first electrode layer. Specifically, referring to step f in Figure 12. S360, providing a first piezoelectric layer. Specifically, referring to step g in Figure 12. S370, providing a temperature compensation layer. Specifically, referring to step h in Figure 12. S380, etching the temperature compensation layer and fabricating the temperature compensation layer body and the second sacrificial unit. Specifically, referring to step i in Figure 12: S390, provide a second piezoelectric layer. Specifically, referring to step j in Figure 12: S3100, provide a second electrode layer. Specifically, referring to step k in Figure 12: S3110, provide a first top electrode film layer. S3120, etch the first top electrode film layer and prepare the first top electrode layer and the third cavity. S3130, fill the third cavity with a third sacrificial unit. Specifically, referring to step l in Figure 12, prepare the first top electrode film layer, and form the first top electrode layer 710 and the third cavity 711 by patterning and etching the first top electrode film layer. To ensure the subsequent preparation of the second top electrode layer, fill the third cavity 711 with a third sacrificial unit 711a. S3140, provide a second top electrode layer. Specifically, referring to step m in Figure 12, prepare a second top electrode layer 720, which covers the first top electrode layer 710 and the third sacrificial unit 711a. The first top electrode layer 710 and the second top electrode layer 720 are top electrode structures 700. By setting the top electrode structure 700, the signal transmission effect of the resonator 10 can be improved, thereby ensuring the reliability of the resonator 10.

[0090] Furthermore, the orthographic projection of the top electrode structure 700 onto the substrate 100 at least partially overlaps with the orthographic projection of the second electrode layer 600 onto the substrate 100, while the orthographic projection of the top electrode structure 700 onto the substrate 100 does not overlap with the orthographic projection of the second electrode portion 220 onto the substrate 100. Therefore, the arrangement of the top electrode structure 700 can be guaranteed not to obstruct the second gap S2, thereby improving signal transmission performance without affecting the fabrication of the second cavity 420. S3150: Remove the second sacrificial unit and fabricate the second cavity, simultaneously remove the third sacrificial unit and fabricate the third cavity. Specifically, referring to step n in Figure 12, the second top electrode layer 720 is fabricated to cover the first top electrode layer 710 and the third cavity 711, etc., and the third sacrificial unit 711a in the third cavity 711 is etched to form the third cavity 711. The second cavity 420 and the third cavity 711 can be fabricated simultaneously, i.e., the second sacrificial unit 421 in the second cavity 420 and the third sacrificial unit 711a in the third cavity 711 are etched simultaneously. The number of third cavities 711 in the resonator 10 can be adjusted adaptively according to actual needs; this embodiment of the invention does not impose a specific limitation on this. Optionally, the material filling the second cavity 420 and the third cavity 711 can be silicon dioxide, etc. Optionally, referring to FIG4, the orthographic projection of the third cavity 711 onto the substrate 100 and the orthographic projection of the second cavity 420 onto the substrate 100 can be either overlapping or non-overlapping, demonstrating the flexibility in the arrangement of the third cavity 711. S3160, Remove the first sacrificial unit and fabricate the first cavity. Specifically, refer to step o in FIG12.

[0091] In summary, the resonator fabrication method provided by the embodiments of the present invention can ensure the stability of the resonator signal transmission by adding a top electrode structure. Furthermore, by fabricating the second and third cavities simultaneously, the manufacturing cost of the resonator can be reduced. Industrial applicability

[0092] The resonator and its fabrication method provided in this application, by adding a top electrode structure, can ensure the stability of the resonator signal transmission in industrial applications. By fabricating the second cavity and the third cavity simultaneously, the manufacturing cost of the resonator can be reduced in industrial production.

Claims

1. A resonator, characterized in that, It includes a substrate, a first electrode layer, a first piezoelectric layer, a temperature compensation layer, a second piezoelectric layer, and a second electrode layer; The substrate includes a first cavity that penetrates a portion of the substrate; The first electrode layer is located on one side of the substrate; the first piezoelectric layer is located on the side of the first electrode layer away from the substrate; The temperature compensation layer includes a temperature compensation layer body and a second cavity. The temperature compensation layer is located on the side of the first piezoelectric layer away from the first electrode layer. The orthographic projection of the temperature compensation layer body onto the substrate is located near the orthographic projection of the second cavity onto the substrate, which is close to the center of the first cavity. There is a first gap between the orthographic projection of the temperature compensation layer body onto the substrate and the orthographic projection of the second cavity onto the substrate. The second piezoelectric layer is located on the side of the temperature compensation layer away from the first piezoelectric layer; there is a second gap between the orthogonal projection of the second piezoelectric layer onto the substrate and the orthogonal projection of the first piezoelectric layer onto the substrate, and the orthogonal projection of the second gap onto the substrate overlaps with the orthogonal projection of the second cavity onto the substrate; The second electrode layer is located on the side of the second piezoelectric layer away from the temperature compensation layer.

2. The resonator according to claim 1, characterized in that, The first electrode layer includes a first electrode portion and a second electrode portion that are interconnected. The orthographic projection of the first electrode portion onto the substrate at least partially overlaps with the orthographic projection of the first cavity, and the orthographic projection of the second electrode portion onto the substrate does not overlap with the orthographic projection of the first cavity.

3. The resonator according to claim 1, characterized in that, The second piezoelectric layer includes a first piezoelectric portion, a second piezoelectric portion, and a third piezoelectric portion. The first piezoelectric portion is located on the side of the first piezoelectric layer away from the first electrode layer, and the orthographic projection of the first piezoelectric portion onto the substrate does not overlap with the first cavity. The third piezoelectric portion is located on the side of the first piezoelectric layer away from the substrate, and the orthographic projection of the third piezoelectric portion onto the substrate does not overlap with the orthographic projection of the first electrode layer onto the substrate. The orthographic projection of the second piezoelectric portion onto the substrate overlaps with the first cavity. The second piezoelectric portion includes a first piezoelectric unit, a second piezoelectric unit, and a third piezoelectric unit. The first piezoelectric unit is located on the side of the second cavity away from the first electrode layer. The second piezoelectric unit is located on the side of the first piezoelectric layer away from the first electrode layer. The third piezoelectric unit is located on the side of the temperature compensation layer body away from the first electrode layer. The first piezoelectric portion projected onto the substrate and the second piezoelectric portion projected onto the substrate have a second gap, and the second gap projected onto the substrate and the second cavity projected onto the substrate at least partially overlap.

4. The resonator according to claim 1, characterized in that, The second electrode layer includes a third electrode portion and a fourth electrode portion that are interconnected. The third electrode portion is located on the side of the second piezoelectric layer away from the first piezoelectric layer, and the orthographic projection of the third electrode portion onto the substrate overlaps with the orthographic projection of the first cavity onto the substrate. The fourth electrode portion is located on the side of the second piezoelectric layer away from the first piezoelectric layer, and the orthographic projection of the fourth electrode portion onto the substrate does not overlap with the orthographic projection of the first electrode layer onto the substrate, nor does it overlap with the orthographic projection of the first cavity onto the substrate. The orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate.

5. The resonator according to claim 1, characterized in that, The resonator further includes a top electrode structure located on the side of the second electrode layer away from the second piezoelectric layer. The orthographic projection of the top electrode structure onto the substrate at least partially overlaps with the orthographic projection of the second electrode layer onto the substrate, and the orthographic projection of the top electrode structure onto the substrate overlaps with the first cavity onto the substrate. The top electrode structure includes a first top electrode layer and a second top electrode layer, with the first top electrode layer located on the side of the second top electrode layer closer to the second piezoelectric layer. The first top electrode layer further includes a third cavity penetrating the first top electrode layer.

6. The resonator according to claim 5, characterized in that, The orthographic projection of the third cavity onto the substrate does not overlap with the orthographic projection of the second cavity onto the substrate.

7. The resonator according to claim 1, characterized in that, Along the first direction, the length of the temperature compensation layer body is L1, the length of the second cavity is L2, and the length of the first gap is L2; ​​wherein, L3 / (L1+L2+L3)≤1%, L1>0, L2>0, and L3>0; wherein, the first direction is parallel to the plane where the substrate is located.

8. The resonator according to claim 1, characterized in that, The scandium doping ratio in the material of the first piezoelectric layer is n1, and the scandium doping ratio in the material of the second piezoelectric layer is n2; wherein, n1>n2, n2≥0.

9. The resonator according to claim 1, characterized in that, The second cavity surrounds at least a portion of the temperature compensation layer body.

10. The resonator according to claim 9, characterized in that, The temperature compensation layer further includes a fourth cavity, which is located on the side of the second cavity away from the temperature compensation layer body, and the fourth cavity is connected to the second cavity.

11. The resonator according to claim 1, characterized in that, The resonator further includes a seed layer located on the side of the first electrode layer near the substrate.

12. A method for fabricating a resonator, used to fabricate the resonator according to any one of claims 1-11, characterized in that, The fabrication method includes: providing a substrate; etching the substrate and fabricating a first cavity, the first cavity penetrating a portion of the substrate; filling the first cavity with a first sacrificial unit; providing a first electrode layer located on one side of the substrate; providing a first piezoelectric layer located on the side of the first electrode layer away from the substrate; providing a temperature compensation layer located on the side of the first electrode layer away from the first electrode layer; etching the temperature compensation layer and fabricating a temperature compensation layer body and a second sacrificial unit; the orthographic projection of the temperature compensation layer body onto the substrate is located near the orthographic projection of the second sacrificial unit onto the substrate, close to the center of the first cavity. Furthermore, a first gap exists between the orthographic projection of the temperature compensation layer body onto the substrate and the orthographic projection of the second sacrificial unit onto the substrate; a second piezoelectric layer is provided, the second piezoelectric layer being located on the side of the temperature compensation layer away from the first piezoelectric layer, a second gap exists between the orthographic projection of the second piezoelectric layer onto the substrate and the orthographic projection of the first piezoelectric layer onto the substrate, and the orthographic projection of the second gap onto the substrate overlaps with the orthographic projection of the second cavity onto the substrate; a second electrode layer is provided, the second electrode layer being located on the side of the second piezoelectric layer away from the temperature compensation layer; the second sacrificial unit is removed and a second cavity is prepared; the first sacrificial unit is removed and a first cavity is prepared.

13. The preparation method according to claim 12, characterized in that, Providing a first electrode layer includes: providing a first electrode film layer located on one side of the substrate; etching the first electrode film layer and fabricating the first electrode layer, the first electrode layer including a first electrode portion and a second electrode portion connected to each other, the orthographic projection of the first electrode portion onto the substrate at least partially overlapping the orthographic projection of the first cavity, and the orthographic projection of the second electrode portion onto the substrate not overlapping the orthographic projection of the first cavity. Providing a second piezoelectric layer includes: providing a second piezoelectric layer comprising a first piezoelectric portion, a second piezoelectric portion, and a third piezoelectric portion; the first piezoelectric portion being located on the side of the first piezoelectric layer away from the first electrode layer, and the orthographic projection of the first piezoelectric portion onto the substrate at least partially overlapping the orthographic projection of the second electrode portion onto the substrate; the third piezoelectric portion being located on the side of the first piezoelectric layer away from the substrate, and the orthographic projection of the third piezoelectric portion onto the substrate not overlapping the orthographic projection of the first electrode layer onto the substrate; the second piezoelectric portion comprising a first piezoelectric unit, a second piezoelectric unit, and a third piezoelectric unit; the first piezoelectric unit being located on the side of the second sacrificial unit away from the first electrode portion; the second piezoelectric unit being located on the side of the temperature compensation layer body away from the first electrode portion; a second gap existing between the orthographic projection of the first piezoelectric portion onto the substrate and the orthographic projection of the second piezoelectric portion onto the substrate, and the orthographic projection of the second gap onto the substrate at least partially overlapping the orthographic projection of the second sacrificial unit onto the substrate; Providing a second electrode layer includes: providing a second electrode layer comprising a third electrode portion and a fourth electrode portion interconnected, the third electrode portion being located on the side of the second piezoelectric portion away from the first piezoelectric layer, the orthographic projection of the third electrode portion onto the substrate at least partially overlapping the orthographic projection of the first electrode portion onto the substrate, the fourth electrode portion being located on the side of the third piezoelectric portion away from the first piezoelectric layer, the orthographic projection of the fourth electrode portion onto the substrate not overlapping the orthographic projection of the first electrode layer onto the substrate; wherein, the orthographic projection of the second electrode layer onto the substrate does not overlap with the orthographic projection of the second gap onto the substrate.

14. The preparation method according to claim 13, characterized in that, After providing the second electrode layer, it also includes: The resonator includes: providing a first top electrode film layer located on the side of the second piezoelectric layer away from the first piezoelectric layer; etching the first top electrode film layer to form a first top electrode layer and a third cavity, the third cavity penetrating the first top electrode layer; filling the third cavity with a third sacrificial unit; providing a second top electrode layer located on the side of the first top electrode layer away from the second piezoelectric layer; wherein the resonator further includes a top electrode structure located on the side of the second electrode layer away from the second piezoelectric layer, the orthogonal projection of the top electrode structure onto the substrate at least partially overlapping the orthogonal projection of the second electrode layer onto the substrate, and the orthogonal projection of the top electrode structure onto the substrate not overlapping the orthogonal projection of the second electrode portion onto the substrate; removing the second sacrificial unit and forming a second cavity includes: removing the second sacrificial unit and forming a second cavity, and simultaneously removing the third sacrificial unit and forming a third cavity.

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