Resonator, preparation method thereof and filter

Abstract

The invention provides a resonator, a preparation method thereof and a filter, and relates to the technical field of semiconductors. In the resonator, a first electrode layer and a second electrode layer are located on the two sides of a piezoelectric layer in the direction parallel to the plane where a substrate is located, and a transverse sandwich structure is formed. A longitudinal sandwich structure in the prior art can be understood as a surface distribution structure, and a transverse sandwich structure in the application can be understood as a line distribution structure. Obviously, compared with a longitudinal sandwich structure, the transverse sandwich structure can greatly reduce the area of the occupied area, the size of the prepared resonator can be remarkably reduced, and miniaturization design of the device is facilitated.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a resonator and a preparation method thereof, and a filter. Background Art

[0002] With the rapid development of wireless communications, wireless signals are becoming more and more crowded, which places higher requirements on resonators working in the radio frequency band.

[0003] In the current prior art, the lower electrode layer, the piezoelectric layer and the upper electrode layer of the resonator are stacked in sequence in the vertical direction to form a longitudinal sandwich structure. The device size is large, which is not conducive to the miniaturization design of the device. Summary of the invention

[0004] In view of the above problems, the present application provides a resonator and a method for manufacturing the same, and a filter. The specific solution is as follows:

[0005] A first aspect of the present application provides a resonator, the resonator comprising: a substrate;

[0006] a piezoelectric layer located on one side of the substrate;

[0007] A first electrode layer and a second electrode layer are located at two sides of the piezoelectric layer in a first direction, wherein the first direction is parallel to a plane where the substrate is located.

[0008] Preferably, in the above resonator, the resonator further comprises:

[0009] A passivation layer, the passivation layer comprising a top portion and a sidewall portion, the top portion is arranged opposite to the substrate, the passivation layer is fixed on the substrate through the sidewall portion, and the passivation layer and the substrate form a cavity;

[0010] The piezoelectric layer, the first electrode layer, and the second electrode layer are located in the cavity.

[0011] Preferably, in the above resonator, the first electrode layer includes a first electrode portion and a second electrode portion;

[0012] The first electrode portion is located between the top portion and the substrate; in a second direction, a first side of the first electrode portion contacts the top portion, and a second side of the first electrode portion contacts the substrate; the second direction is perpendicular to the first direction;

[0013] The second electrode portion is located on the substrate; in the first direction, a first side of the second electrode portion contacts a second side of the first electrode portion, and the second side of the second electrode portion extends in a direction away from the second electrode layer.

[0014] Preferably, in the above resonator, the top portion has a first through hole; the resonator further comprises: a first pad;

[0015] The first pad is located at a side of the top portion facing away from the substrate, and the first pad is connected to the second electrode portion through the first through hole.

[0016] Preferably, in the above resonator, the second electrode portion extends to the outside of the passivation layer;

[0017] The resonator further includes: a first pad;

[0018] The first pad is connected to a first target electrode, which is an electrode portion where the second electrode portion extends outside the passivation layer.

[0019] Preferably, in the above resonator, the second electrode layer includes a third electrode portion and a fourth electrode portion;

[0020] The third electrode portion is located between the top portion and the substrate; in a second direction, a first side of the third electrode portion contacts the top portion, and a second side of the third electrode portion contacts the substrate; the second direction is perpendicular to the first direction;

[0021] The fourth electrode portion is located on the substrate; in the first direction, a first side of the fourth electrode portion contacts a second side of the third electrode portion, and the second side of the fourth electrode portion extends in a direction away from the first electrode layer.

[0022] Preferably, in the above resonator, the top portion has a second through hole; the resonator further comprises: a second pad;

[0023] The second pad is located at a side of the top portion facing away from the substrate, and the second pad is connected to the fourth electrode portion through the second through hole.

[0024] Preferably, in the above resonator, the fourth electrode portion extends to the outside of the passivation layer;

[0025] The resonator further includes: a second pad;

[0026] The second pad is connected to a second target electrode, which is an electrode portion of the fourth electrode portion extending outside the passivation layer.

[0027] A second aspect of the present application provides a method for preparing a resonator, the method comprising:

[0028] providing a substrate;

[0029] forming a piezoelectric layer on the substrate;

[0030] forming an electrode layer, wherein the electrode layer covers the piezoelectric layer;

[0031] The electrode layer is etched once to form a first electrode layer and a second electrode layer; the first electrode layer and the second electrode layer are located on both sides of the piezoelectric layer in a first direction, and the first direction is parallel to the plane where the substrate is located.

[0032] A third aspect of the present application provides a filter, comprising the resonator described in any one of the above items.

[0033] By means of the above technical solution, the present application provides a resonator and a method for preparing the same, and a filter, in which the first electrode layer and the second electrode layer are located on both sides of the piezoelectric layer in a direction parallel to the plane where the substrate is located, forming a transverse sandwich structure. The longitudinal sandwich structure in the prior art can be understood as a surface distribution structure, and the transverse sandwich structure in the present application can be understood as a line distribution structure. Obviously, compared with the longitudinal sandwich structure, the transverse sandwich structure can greatly reduce the area occupied, and the size of the prepared resonator will be significantly reduced, which is conducive to the miniaturization design of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0035] Figure 1 It is a structural schematic diagram of a resonator in the prior art;

[0036] Figure 2 A schematic diagram of the structure of a resonator provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of the structure of another resonator provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a process for preparing a resonator provided by an embodiment of the present invention;

[0039] Figure 5-Figure 14 for Figure 4 Schematic diagram of the partial structure corresponding to the preparation method shown. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] It should be noted that the directional words appearing in the present invention are based on the relative position relationship shown in the drawings and cannot be used as an absolute limitation to the present application.

[0043] refer to Figure 1 , Figure 1 is a schematic diagram of the structure of a resonator in the prior art, refer to Figure 2 , Figure 2 A schematic diagram of the structure of a resonator provided in an embodiment of the present invention. The resonator provided in an embodiment of the present invention comprises: a substrate 11.

[0044] The piezoelectric layer 12 is located on one side of the substrate 11 .

[0045] The first electrode layer 13 and the second electrode layer 14 are located at both sides of the piezoelectric layer 12 in a first direction X, and the first direction X is parallel to the plane where the substrate 11 is located.

[0046] Specifically, in the embodiment of the present invention, in a direction parallel to the plane where the substrate 11 is located (also understood as a horizontal direction), the first electrode layer 13 and the second electrode layer 14 are located on both sides of the piezoelectric layer 12 to form a lateral sandwich structure. Figure 1 As shown, the longitudinal sandwich structure 10 in the prior art can be understood as a surface distribution structure; Figure 2 As shown, the transverse sandwich structure in the embodiment of the present application can be understood as a linear distribution structure. Obviously, compared with the longitudinal sandwich structure, the transverse sandwich structure can greatly reduce the area occupied, and the size of the prepared resonator will be significantly reduced, which is conducive to the miniaturization design of the device and more conducive to the integration of multiplexers.

[0047] In an optional embodiment of the present invention, reference Figure 3 , Figure 3 FIG. 1 is a schematic diagram of the structure of another resonator provided in an embodiment of the present invention. Figure 2 and Figure 3 As shown, the resonator provided by the embodiment of the present invention also includes:

[0048] The passivation layer 15 includes a top portion and a sidewall portion. The top portion is arranged opposite to the substrate 11. The passivation layer 15 is fixed on the substrate 11 through the sidewall portion. The passivation layer 15 and the substrate 11 form a cavity.

[0049] The piezoelectric layer 12 , the first electrode layer 13 , and the second electrode layer 14 are located in the cavity.

[0050] Specifically, in the embodiments of the present invention, the applicant found that Figure 1 The resonator shown will require another wafer as a bonding cover later (it should be noted that Figure 1 The bonding cover plate is not shown in the example) to make the cavity, resulting in a large number of wafers required for the device, which in turn leads to a high manufacturing cost of the device. Figure 2 and Figure 3 As shown, the shape design of the passivation layer 15 cooperates with the substrate 11 to realize the packaging of the resonator and the required cavity, and no additional wafer is needed for packaging. Figure 1 As for the resonator shown in FIG. 1 , the number of wafers used in the resonator provided by the embodiment of the present invention is reduced, thereby reducing the production cost of the resonator.

[0051] In an optional embodiment of the present invention, Figure 2 As shown, the first electrode layer 13 includes a first electrode portion and a second electrode portion.

[0052] The first electrode portion is located between the top portion and the substrate 11; in a second direction YY, a first side of the first electrode portion contacts the top portion, and a second side of the first electrode portion contacts the substrate 11; the second direction Y is perpendicular to the first direction X.

[0053] The second electrode portion is located on the substrate 11 ; in the first direction X, a first side of the second electrode portion contacts a second side of the first electrode portion, and the second side of the second electrode portion extends in a direction away from the second electrode layer 14 .

[0054] The top portion has a first through hole; the resonator further includes: a first pad 16 .

[0055] The first pad 16 is located at a side of the top portion facing away from the substrate 11 , and the first pad 16 is connected to the second electrode portion through the first through hole.

[0056] Specifically, in the embodiment of the present invention, the first pad 16 is connected to the first electrode layer 13 in the cavity, and only a small part is located outside the passivation layer 15. This design does not increase the size of the overall structure while ensuring that the resonator is electrically connected to the outside, which is conducive to the miniaturization design of the device and is more conducive to the integration of the multiplexer.

[0057] In an optional embodiment of the present invention, Figure 2 As shown, the second electrode layer 14 includes a third electrode portion and a fourth electrode portion.

[0058] The third electrode portion is located between the top portion and the substrate 11; in the second direction Y, the first side of the third electrode portion contacts the top portion, and the second side of the third electrode portion contacts the substrate 11; the second direction Y is perpendicular to the first direction X.

[0059] The fourth electrode portion is located on the substrate 11; in the first direction X, a first side of the fourth electrode portion contacts a second side of the third electrode portion, and the second side of the fourth electrode portion extends in a direction away from the first electrode layer.

[0060] The top portion has a second through hole; the resonator further includes: a second pad 17 .

[0061] The second pad 17 is located at a side of the top portion facing away from the substrate 11 , and the second pad 17 is connected to the fourth electrode portion through the second through hole.

[0062] Specifically, in the embodiment of the present invention, the second pad 17 is connected to the second electrode layer 14 in the cavity, and only a small part is located outside the passivation layer 15. This design can ensure that the resonator is electrically connected to the outside without increasing the size of the overall structure, which is conducive to the miniaturization design of the device and is more conducive to the integration of the multiplexer.

[0063] In an optional embodiment of the present invention, Figure 3 As shown, the second electrode portion extends to the outside of the passivation layer 15 .

[0064] The resonator further includes a first pad 16 .

[0065] The first pad 16 is connected to a first target electrode, which is an electrode portion of the second electrode portion extending to the outside of the passivation layer 15 .

[0066] Specifically, in the embodiment of the present invention, the first electrode layer 13 is led outward to the outside of the passivation layer 15, and the first pad 16 is formed on the outer wall of the passivation layer 15 in an attached manner, that is, the first pad 16 is made outside the cavity. In the case of connecting the first pad 16 to the first electrode layer 13, since the first pad 16 is formed on the outer wall of the passivation layer 15 in an attached manner, the reliability of the first pad 16 can be improved, thereby improving the structural stability of the resonator.

[0067] In an optional embodiment of the present invention, Figure 3 As shown, the fourth electrode portion extends to the outside of the passivation layer 15 .

[0068] The resonator further includes a second pad 17 .

[0069] The second pad 17 is connected to a second target electrode, which is an electrode portion of the fourth electrode portion extending to the outside of the passivation layer 15 .

[0070] Specifically, in the embodiment of the present invention, the second electrode layer 14 is led outward to the outside of the passivation layer 15, and the second pad 17 is formed on the outer wall of the passivation layer 15 in an attached manner, that is, the second pad 17 is made outside the cavity. In the case of realizing the connection between the second pad 17 and the second electrode layer 14, since the second pad 17 is formed on the outer wall of the passivation layer 15 in an attached manner, the reliability of the second pad 17 can be improved, thereby improving the structural stability of the resonator.

[0071] Based on the above embodiment of the present invention, another embodiment of the present invention further provides a method for preparing a resonator, referring to Figure 4 , Figure 4 A schematic diagram of a process for preparing a resonator provided in an embodiment of the present invention. Figure 2 The resonator shown in FIG. 1 is used as an example for explanation. The method for preparing a resonator provided in an embodiment of the present invention includes:

[0072] S101: Figure 5 As shown, a substrate 11 is provided.

[0073] Specifically, in this step, the substrate 11 includes but is not limited to a high-resistance silicon substrate.

[0074] S102: Figure 5 , Figure 6 and Figure 7 As shown, a piezoelectric layer 12 is formed on the substrate 11 .

[0075] Specifically, in this step, Figure 5As shown, a piezoelectric layer 12 is formed on the surface of the substrate 11. The piezoelectric layer 12 may be a piezoelectric layer made of a single crystal material, a piezoelectric layer made of a polycrystalline material, a piezoelectric layer made of an AlN material, a piezoelectric layer made of an AlScN material, or a piezoelectric layer made of a quartz material. Figure 6 As shown, the piezoelectric layer 12 is etched to form the piezoelectric layer 12 of the desired pattern.

[0076] In an optional embodiment of the present invention, the angle range of etching the piezoelectric layer 12 can be 85°-90°; the pattern of the piezoelectric layer 12 can be circular, square, triangular or other regular patterns or other irregular patterns; it can also be a closed pattern or an open pattern. This is not limited in the embodiment of the present invention and can be determined according to actual conditions.

[0077] When a plurality of piezoelectric layers 12 are formed by etching on a substrate 11, as shown in FIG. Figure 7 As shown, four piezoelectric layers 12 are formed. At this time, it is necessary to ensure that the spacing between the patterns and the spacing between the patterns is greater than 1μm. That is, A>1μm, B>1μm, and C>1μm. A and C are the spacing between the patterns, and B is the spacing between the patterns. The purpose of this design is to reserve enough space for the deposition of subsequent electrode layers, to ensure that the first electrode layer 13 and the second electrode layer 14 can be formed on both sides of the piezoelectric layer 12 in the first direction X, and that the electrode layers corresponding to the piezoelectric layers 12 of multiple patterns do not affect each other.

[0078] S103: Figure 8 As shown, an electrode layer 18 is formed, and the electrode layer 18 covers the piezoelectric layer 12 .

[0079] S104: Fig. 9 As shown, the electrode layer 18 is etched once to form a first electrode layer 13 and a second electrode layer 14; the first electrode layer 13 and the second electrode layer 14 are located on both sides of the piezoelectric layer 12 in a first direction X, and the first direction X is parallel to the plane where the substrate 11 is located.

[0080] Specifically, it was found during the invention process of this application that Figure 1 The vertical sandwich structure 10 shown in the figure requires two depositions and two etchings when forming the lower electrode layer and the upper electrode layer, which makes the preparation process more complicated and increases the production cost. Figure 8 and Fig. 9 As shown, the first electrode layer 13 and the second electrode layer 14 can be formed by only one deposition and one etching, and the first electrode layer 13 and the second electrode layer 14 can be located on both sides of the piezoelectric layer 12 in the first direction X, which greatly simplifies the preparation process, reduces production costs, and improves production efficiency.

[0081] Optionally, the materials of the first electrode layer 13 and the second electrode layer 14 may be other materials such as Mo / W.

[0082] In an optional embodiment of the present invention, Fig.10 and Fig.11 As shown, the method for preparing a resonator provided by the embodiment of the present invention further includes: preparing a sacrificial layer 19 , where the sacrificial layer 19 is located in a region of a cavity to be formed subsequently, and etching the sacrificial layer 19 to expose an edge region of the substrate 11 .

[0083] In an optional embodiment of the present invention, Fig.12 Shown and Fig.13 As shown, the method for preparing a resonator provided by an embodiment of the present invention further includes: preparing a passivation layer 15, and etching the top portion of the passivation layer 15 and the sacrificial layer 19 to form a pad channel 20. The pad channel 20 exposes the second electrode portion of the first electrode layer 13 and the fourth electrode portion of the second electrode layer 14.

[0084] It should be noted that the penetrating region of the top portion of the passivation layer 15 corresponding to the pad channel 20 can be understood as a through hole penetrating the top portion of the passivation layer 15 .

[0085] In an optional embodiment of the present invention, Fig.14 As shown, the method for preparing a resonator provided by an embodiment of the present invention further includes: preparing a first pad 16 and a second pad 17; the first pad 16 is located on a side of the top portion away from the substrate 11, and the first pad 16 is connected to the second electrode portion through the pad channel 20. The second pad 17 is located on a side of the top portion away from the substrate 11, and the second pad 17 is connected to the fourth electrode portion through the pad channel 20.

[0086] It should be noted that in the embodiment of the present invention, the process for preparing the first pad 16 and the second pad 17 includes but is not limited to a lift-off process or an etching process, and the material of the pad includes but is not limited to Au, Cu or alloys.

[0087] In an optional embodiment of the present invention, Figure 2 As shown, the method for preparing the resonator provided in the embodiment of the present invention further includes: removing the sacrificial layer 19, forming Figure 2 The resonator structure shown.

[0088] Based on the above embodiments of the present invention, a filter is provided in another embodiment of the present invention. The filter includes the resonator described in any of the above embodiments.

[0089] The filter has the same technical effect as the resonator described in any of the above embodiments.

[0090] The resonator and its preparation method and filter provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

[0091] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0092] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0093] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A resonator, characterized in that: The resonator comprises: a substrate; a piezoelectric layer located on one side of the substrate; A first electrode layer and a second electrode layer are located at two sides of the piezoelectric layer in a first direction, wherein the first direction is parallel to a plane where the substrate is located.

2. The resonator according to claim 1, characterized in that The resonator further comprises: A passivation layer, the passivation layer comprising a top portion and a sidewall portion, the top portion is arranged opposite to the substrate, the passivation layer is fixed on the substrate through the sidewall portion, and the passivation layer and the substrate form a cavity; The piezoelectric layer, the first electrode layer, and the second electrode layer are located in the cavity.

3. The resonator according to claim 2, characterized in that The first electrode layer includes a first electrode portion and a second electrode portion; The first electrode portion is located between the top portion and the substrate; In a second direction, a first side of the first electrode portion contacts the top portion, and a second side of the first electrode portion contacts the substrate; The second direction is perpendicular to the first direction; The second electrode portion is located on the substrate; in the first direction, a first side of the second electrode portion contacts a second side of the first electrode portion, and the second side of the second electrode portion extends in a direction away from the second electrode layer.

4. The resonator according to claim 3, characterized in that The top portion has a first through hole; the resonator further comprises: a first pad; The first pad is located at a side of the top portion facing away from the substrate, and the first pad is connected to the second electrode portion through the first through hole.

5. The resonator according to claim 3, characterized in that The second electrode portion extends to the outside of the passivation layer; The resonator further includes: a first pad; The first pad is connected to a first target electrode, which is an electrode portion where the second electrode portion extends outside the passivation layer.

6. The resonator according to claim 2, characterized in that The second electrode layer includes a third electrode portion and a fourth electrode portion; The third electrode portion is located between the top portion and the substrate; In a second direction, a first side of the third electrode portion contacts the top portion, and a second side of the third electrode portion contacts the substrate; The second direction is perpendicular to the first direction; The fourth electrode portion is located on the substrate; in the first direction, a first side of the fourth electrode portion contacts a second side of the third electrode portion, and the second side of the fourth electrode portion extends in a direction away from the first electrode layer.

7. The resonator according to claim 6, characterized in that The top portion has a second through hole; the resonator further comprises: a second pad; The second pad is located at a side of the top portion facing away from the substrate, and the second pad is connected to the fourth electrode portion through the second through hole.

8. The resonator according to claim 6, characterized in that The fourth electrode portion extends to the outside of the passivation layer; The resonator further includes: a second pad; The second pad is connected to a second target electrode, which is an electrode portion of the fourth electrode portion extending outside the passivation layer.

9. A method for preparing a resonator, characterized in that: The preparation method of the resonator comprises: providing a substrate; forming a piezoelectric layer on the substrate; forming an electrode layer, wherein the electrode layer covers the piezoelectric layer; The electrode layer is etched once to form a first electrode layer and a second electrode layer; the first electrode layer and the second electrode layer are located on both sides of the piezoelectric layer in a first direction, and the first direction is parallel to the plane where the substrate is located.

10. A filter, characterized in that: The filter comprises the resonator according to any one of claims 1-8.

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