A resonator and a manufacturing method thereof, a filter, and an electronic device

Abstract

The application provides a resonator, which comprises a substrate, a functional layer on the substrate, the functional layer comprising at least a bottom electrode, a piezoelectric layer and a top electrode, the piezoelectric layer being between the bottom electrode and the top electrode, and a cavity between the bottom electrode and the substrate, wherein the functional layer has a through hole, and a first support structure is arranged on at least part of the inner side wall of the through hole, and the first support structure has a bottom part in contact with the substrate. In the structure, no heat is generated at the through hole; the through hole makes the resonator ring-shaped, and the resonator has good heat dissipation effect; the bottom part of the first support structure is in contact with the substrate, and the functional layer is well supported, and a heat transfer path is formed, so that the heat transfer of the resonator is accelerated, and the heat dissipation capacity of the resonator is enhanced. The application further provides a manufacturing method of the resonator, and a filter and an electronic device comprising the resonator.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a resonator and its manufacturing method, as well as filters and electronic devices. Background Technology

[0002] Film Bulk Acoustic Resonators (FBARs) play an important role in the field of communications due to their excellent characteristics such as small size, high resonant frequency, high quality factor, and large power capacity.

[0003] A typical air-gap resonator consists of a bottom electrode layer, a piezoelectric layer, and a top electrode layer; that is, a piezoelectric material is sandwiched between two metal electrode layers. Its working principle involves inputting an electrical signal between the two metal electrode layers. The piezoelectric film uses the inverse piezoelectric effect to convert the input electrical signal into a mechanical resonant wave, and then uses the piezoelectric effect to convert the mechanical resonant wave back into an electrical signal for output. The bottom electrode, piezoelectric layer, and top electrode are stacked on a substrate, and a cavity is etched into the substrate surface. This cavity effectively confines the sound waves within the piezoelectric resonator.

[0004] Typically, the heat generated during resonator operation relies on lateral heat transfer through the electrode and piezoelectric layers before diffusing into the substrate. However, the central region of the resonator is far from the substrate, preventing timely heat dissipation. This leads to a rise in resonator temperature, causing performance drift towards lower frequencies. Under prolonged high-temperature operation, material damage may occur first in the central region, resulting in device failure and a drastically reduced device lifespan. Especially at high frequencies, the electrode and piezoelectric layers are thinner, resulting in even lower heat transfer efficiency and increased heat generation compared to lower frequencies, causing the heat load on the device's operating area to increase exponentially. Therefore, for high-power FBARs, existing resonator structures suffer from uneven heat distribution and low heat dissipation efficiency, failing to meet power handling requirements. Summary of the Invention

[0005] To alleviate or solve the above problems, the present invention provides a resonator in a first aspect, comprising:

[0006] A substrate; a functional layer located on the substrate, the functional layer including at least a bottom electrode, a piezoelectric layer and a top electrode, the piezoelectric layer being located between the bottom electrode and the top electrode; a cavity being provided between the bottom electrode and the substrate; wherein, the functional layer has a through hole, and a first support structure is provided on at least a portion of the inner sidewall of the through hole, the first support structure having a bottom that contacts the substrate.

[0007] The technical effects of the above-mentioned resonator structure include: in the resonator, the functional layer at the through-hole is partially removed, thus no resonance or heat is generated; the through-hole makes the resonator ring-shaped, which has a better heat dissipation effect; the bottom of the support structure is in contact with the substrate, which provides better support for the functional layer and enhances the mechanical stability of the ring resonator; the bottom of the first support structure is in contact with the substrate, which can also form a heat transfer path, allowing the heat in the resonator to flow into the substrate through the support structure, accelerating the heat transfer of the resonator and enhancing the heat dissipation capacity of the resonator.

[0008] Preferably, the first support structure extends from one of the bottom electrode, piezoelectric layer, or top electrode along the inner sidewall of the via to the bottom surface of the cavity. The materials of the bottom electrode, piezoelectric layer, or top electrode typically have a relatively high thermal conductivity compared to the substrate. Therefore, the support structure formed by extending one of the bottom electrode, piezoelectric layer, or top electrode can accelerate the heat transfer of the resonator. At the same time, the support structure can be formed simultaneously with the bottom electrode, piezoelectric layer, or top electrode, which can simplify the process and facilitate production.

[0009] Furthermore, the first support structure extends to the bottom of the via and at least covers the portion of the bottom surface of the cavity corresponding to the bottom of the via. This preferred embodiment ensures that the first support structure at least covers a portion of the bottom of the substrate, improving its support effect and thermal conductivity.

[0010] Furthermore, the inner wall of the through-hole in the functional layer can be vertical, inclined, or stepped. In a preferred embodiment, the shape of the inner wall of the through-hole can be varied and can be set according to the actual process requirements.

[0011] Preferably, the inner wall of the via in the functional layer is stepped, and the first support structure extends along the via from a portion of the upper surface of one of the bottom electrode, piezoelectric layer, or top electrode to the bottom surface of the cavity. The stepped inner wall of the via forms a region of abrupt change in morphology, which can effectively reflect transverse waves and confine them within the effective resonance region (i.e., the region where the bottom electrode, piezoelectric layer, top electrode, and cavity overlap).

[0012] Furthermore, the first support structure completely covers the inner wall of the through hole, or is distributed discontinuously along the inner wall of the through hole.

[0013] Preferably, the via is located in the central region of the resonator. Typically, the central region of the resonator is where heat is most concentrated; placing the via in the central region can effectively reduce overheating in that area.

[0014] Furthermore, the projection shape of the via on the substrate can be circular, elliptical, or polygonal. Depending on the actual needs, the via can be set to any shape.

[0015] Furthermore, the first support structure is made of the same material as the bottom electrode, piezoelectric layer, or top electrode.

[0016] Preferably, a second support structure is provided above the first support structure, and the second support structure at least covers a portion of the first support structure. The multi-layered support structure can further improve structural strength and conductivity.

[0017] Furthermore, the second support structure extends from the outside of one of the bottom electrode, piezoelectric layer, or top electrode to at least a portion of the surface of the first support structure to cover a portion of the first support structure.

[0018] Furthermore, the second support structure is made of the same material as the first support structure. When the first support structure extends from the bottom electrode, if a second support structure, also made of a metallic material, is superimposed, it will improve the conductivity of the bottom electrode and reduce the series impedance.

[0019] Furthermore, the second support structure is made of a different material than the first support structure. In this case, the mechanical stability of the resonator can be improved through the second support structure. Furthermore, the functional layer also includes one or more of a passivation layer, a support layer, a seed layer, or a temperature compensation layer. The first support structure and the second support structure can be extended from the functional layer, including the passivation layer, the support layer, the seed layer, or the temperature compensation layer.

[0020] Furthermore, the cavity is located on the upper surface of the substrate or embedded inside the substrate. The resonator of this application is applicable to above-ground or underground cavities.

[0021] Preferably, the height of the cavity is less than 2 μm. More preferably, the height of the cavity is 0.5-1.5 μm. This can significantly reduce the cavity height, thereby reducing manufacturing costs, while also providing a shorter heat dissipation path and better heat dissipation.

[0022] In a second aspect, the present invention provides a method for manufacturing a resonator, comprising the following steps:

[0023] A substrate is provided; a cavity is formed on the substrate; a functional layer is formed on the cavity and the substrate, and a via is formed in the functional layer during the formation of the functional layer, the functional layer including at least a bottom electrode, a piezoelectric layer and a top electrode; wherein a first support structure is formed on at least a portion of the inner sidewall of the via, the first support structure extending from the inner sidewall of the via to the bottom surface of the cavity.

[0024] Furthermore, in this manufacturing method, the first support structure is integrally formed with the functional layer.

[0025] Furthermore, in this manufacturing method, the first support structure is formed in the same layer as the top electrode, and there is a break between the first support structure and the top electrode to achieve electrical isolation.

[0026] In a third aspect, the present invention provides a filter comprising the resonator described above.

[0027] In a fourth aspect, the present invention provides an electronic device comprising the resonator described above.

[0028] The resonator proposed in this invention effectively reduces heat generation by setting through holes in the functional layer so that resonance does not occur at the corresponding positions of the through holes; a support structure is provided on at least part of the inner sidewall of the through holes to provide effective support for the functional layer; the support structure has a bottom that contacts the substrate, allowing heat to flow into the substrate through the support structure, thereby improving the heat dissipation efficiency of the resonator. Attached Figure Description

[0029] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. Other embodiments and many anticipated advantages of the embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0030] Figure 1 A cross-sectional view of a resonator according to an embodiment of the present invention is shown;

[0031] Figure 2 This is a schematic diagram of the heat transfer path in a conventional resonator in the prior art;

[0032] Figure 3 for Figure 2 The thermogram corresponding to the resonator shown;

[0033] Figure 4 for Figure 1 The diagram shows the heat transfer path of the resonator.

[0034] Figure 5 for Figure 1 The thermogram corresponding to the resonator shown;

[0035] Figure 6 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0036] Figure 7 for Figure 1 A partial enlarged view of the inner wall of the through hole of the resonator shown;

[0037] Figure 8 for Figure 1 The top view of the resonator shown;

[0038] Figure 9A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0039] Figure 10 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0040] Figure 11 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0041] Figure 12 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0042] Figure 13 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0043] Figure 14 A cross-sectional view of a resonator according to another embodiment of the present invention is shown;

[0044] Figures 15a-15i A fabrication process flow diagram of a thin-film bulk acoustic resonator according to an embodiment of the present invention is shown. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] Because the components of the embodiments can be positioned in several different orientations, the orientations in the reference figures use directional terms such as "top," "bottom," "left," "right," "up," "down," etc., to describe some embodiments. It is understood that the use of directional terms for illustrative purposes is by no means limiting. Other embodiments may be utilized or logical changes may be made without departing from the scope of the invention. Where there is no conflict, the embodiments and features described in this application can be combined with each other.

[0047] Figure 1 A cross-sectional view of a resonator 100 according to an embodiment of the present invention is shown. Figure 8 This is a top view of resonator 100, where a cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening in the support structure. Specifically, refer to... Figure 8 In the section A-A', the top-view direction refers to the view of the resonator with the substrate as its bottom plane. (Reference) Figure 1The resonator 100 includes a substrate 101; a functional layer on the substrate 101, the functional layer including at least a bottom electrode 103, a piezoelectric layer 104, and a top electrode 105, the piezoelectric layer 104 being located between the bottom electrode 103 and the top electrode 105; a cavity 102 being formed between the bottom electrode 103 and the substrate 101; wherein, the functional layer has a through-hole, and a first support structure 106 is provided on at least a portion of the inner sidewall of the through-hole, the first support structure 106 having a bottom that contacts the substrate 101. The region where the through-hole is located does not generate resonance, and therefore does not generate heat, reducing heat generation within the resonator; after the through-hole is formed, the effective resonance region is annular, and the annular structure helps with heat dissipation. The support structure can improve the stability of the resonator: conventional resonators mainly rely on the edge of the bottom electrode for support. However, the resonator area is large at low frequencies and the piezoelectric layer and electrode thickness are very thin at high frequencies, which will reduce the structural strength of the resonator. The support structure set according to this embodiment can enhance the stability of the resonator, improve mechanical reliability, and ensure the effective area of ​​the resonator. In addition, the support structure can also serve as a heat conduction path, transferring heat to the substrate through the support structure, which improves the heat dissipation efficiency of the resonator compared to conventional resonator structures.

[0048] Figures 2-5 Further clarification shows that the support structure can effectively improve the heat dissipation efficiency of the resonator. Figure 2 This is a schematic diagram of the heat transfer path of a resonator 100' commonly used in existing technologies. Figure 3 This is a thermal diagram corresponding to resonator 100', where the numbers represent the temperature values ​​at those locations. A typical resonator 100' includes a substrate 101'; a bottom electrode 103', a piezoelectric layer 104', and a top electrode 105' located on the substrate 101', with the piezoelectric layer 104' situated between the bottom electrode 103' and the top electrode 105'; a cavity 102' exists between the bottom electrode 103' and the substrate 101'; its heat transfer path is as follows... Figure 2 As indicated by the middle arrow, since air is a poor conductor of heat, the resonator 100' primarily transfers heat to a portion of the substrate near the resonator through the electrodes and piezoelectric layer. This portion of the substrate then transfers the heat to the entire substrate before dissipating it to the outside. Typically, the distance between the center of the effective resonant region and the substrate on the side of the cavity is relatively large, meaning the heat transfer distance is long, and the heat cannot be conducted away quickly. Therefore, heat accumulates in the central region A of the resonator. (See [reference]). Figure 3 Overheating in the central region A of the resonator can easily cause frequency drift or accelerate the aging of the piezoelectric stack structure, thus affecting the performance of the resonator. Figure 4 This is a schematic diagram of the heat transfer path of the resonator 100. Figure 5 This is the thermal diagram corresponding to resonator 100. The numbers in the thermal diagram represent the temperature values ​​at those locations. For example... Figure 4As shown, resonance no longer occurs in the area where the through-hole of the resonator is located, reducing heat generation; simultaneously, the support structure is in contact with the substrate, allowing heat to be transferred from the support structure to the substrate, increasing the heat dissipation path and improving the resonator's heat dissipation capacity. (Comparison) Figure 3 and Figure 5 As can be seen, the operating temperature range of resonator 100' is approximately 313K-343K, with the highest temperature occurring in the central region of the resonator, and the temperature distribution gradually decreasing outward from the central region. In contrast, the operating temperature range of resonator 100 is approximately 298K-313K. Compared to resonator 100', the central region of the resonator has the lowest heat, while the highest temperature occurs between the outer edge of the recessed region and the outer edge of the resonator, exhibiting a ring-shaped distribution. Therefore, in this embodiment, the overall heat of the resonator is significantly reduced, and the heat distribution is more uniform, resulting in a substantial improvement in the long-term operating performance of the resonator.

[0049] In a preferred embodiment, the first support structure extends from one of the bottom electrode, piezoelectric layer, or top electrode along the inner wall of the via to the bottom surface of the cavity. The following detailed description uses the example of the first support structure extending from the top electrode or piezoelectric layer along the inner wall of the via to the bottom surface of the cavity as an example. (Refer to...) Figure 1 The first support structure 106 extends from the top electrode 105 along the inner wall of the through hole to the bottom surface of the cavity 102. At the edge of the effective resonance region, there is a break 108 between the top electrode 105 and the first support structure 106 to achieve electrical isolation and avoid short circuit between electrodes. Figure 6 This is a cross-sectional view of the resonator 200 in another preferred embodiment, where the cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening in the support structure. In this embodiment, the resonator 200 includes a substrate 201; a functional layer located on the substrate 201, the functional layer including at least a bottom electrode 203, a piezoelectric layer 204, and a top electrode 205, the piezoelectric layer 204 being located between the bottom electrode 203 and the top electrode 205; a cavity 202 being formed between the bottom electrode 203 and the substrate 201; wherein, the functional layer has a through-hole, and a first support structure 206 is provided on at least a portion of the inner sidewall of the through-hole, the main difference from the resonator 100 being that the first support structure 206 extends from the piezoelectric layer 204 along the inner sidewall of the through-hole to the bottom surface of the cavity 202.

[0050] The advantages of setting the first support structure to extend from one of the bottom electrode, piezoelectric layer, or top electrode include: in the prior art, the materials of the bottom electrode, piezoelectric layer, or top electrode typically have a higher thermal conductivity than the substrate (see Table 1), where Si is a commonly used substrate material, Mo is a commonly used electrode material, and AlN is a commonly used piezoelectric layer material. It is evident that the thermal conductivity of the substrate is much lower than that of the resonator functional layer. Transferring heat from the resonator through the functional layer can accelerate heat transfer. Simultaneously, the first support structure can be formed simultaneously with the bottom electrode, piezoelectric layer, or top electrode during manufacturing, simplifying the process. In other embodiments, depending on actual needs, the first support structure can also be made of a different material than the electrode or piezoelectric layer, formed by other processes.

[0051] Table 1 Thermal conductivity of commonly used materials for different resonator structures

[0052]

[0053] In a preferred embodiment, reference Figure 1 The first support structure 106 extends to the bottom of the through-hole and further covers at least a portion of the bottom surface of the cavity 102 corresponding to the bottom of the through-hole. At this point, the first support structure completely covers the bottom of the through-hole and partially covers the surface of the substrate, giving it a large support area on the substrate. It should be noted that the contact area between the support structure and the substrate can be equal to, greater than, or smaller than the area of ​​the bottom of the through-hole.

[0054] In specific embodiments, the shape of the inner sidewall of the via can be vertical, inclined, or stepped, such that the via is perpendicular to the substrate or inclined to the substrate surface, and the inner sidewall can be stepped. In a preferred embodiment, during the fabrication of the resonator, a portion of the upper surface of at least one of the bottom electrode, piezoelectric layer, or top electrode is exposed in the via, thereby forming a stepped inner sidewall of the via in the functional layer, and the first support structure extends along the via from a portion of the upper surface of one of the bottom electrode, piezoelectric layer, or top electrode to the bottom surface of the cavity.

[0055] In a further preferred embodiment, refer to Figure 1 The first support structure 106 extends from a portion of the upper surface of the piezoelectric layer 104 along the inner wall of the through hole to the bottom surface of the cavity 102. During the manufacturing process of the resonator, the first support structure 106 can be formed simultaneously with the top electrode 105. Figure 7 For resonator 100 in Figure 1 The enlarged view of the structure inside the dashed coil shows that three steps are formed on the inner sidewall of the through hole at the position indicated by the arrow, thus creating a morphological abrupt change. The morphological abrupt change at the edge of the functional layer can reflect transverse waves and confine them within the effective resonance region.

[0056] In another preferred embodiment, reference Figure 6 Part of the upper surface of the piezoelectric layer 204 is exposed in the via, causing a step to be formed on the inner sidewall of the via at the arrow, thus creating a morphological abrupt change. The morphological abrupt change at the edge of the functional layer can reflect transverse waves and confine them to the effective resonant region.

[0057] In specific embodiments, depending on actual needs, the first support structure can be continuous, completely covering the inner wall of the through hole, or it can be discontinuously distributed along the inner wall of the through hole, both of which can achieve the supporting effect.

[0058] In a preferred embodiment, the via is located in the central region of the resonator. (See reference) Figure 8 The via is located within the central region of the resonator 100. See also... Figure 3 For conventional resonators, the central region is typically the area with the most severe heat accumulation due to its distance from the substrate on the side of the cavity. Placing vias in the central region of the resonator can effectively reduce overheating in this area. It is understandable that vias can also be placed off-center.

[0059] This invention does not limit the cross-sectional shape of the through hole; it can be circular, elliptical, a regular polygon with each angle greater than 90°, or an irregular polygon with each angle greater than 90°. Its length-to-width ratio and other characteristics can also be adjusted as needed. (Reference) Figure 8 In this embodiment, the through-hole shape of the resonator 100 is set to an irregular pentagon.

[0060] In a specific embodiment, depending on actual needs, the first support structure is made of the same material as the bottom electrode, piezoelectric layer, or top electrode. During the manufacturing process, the first support structure can be formed simultaneously with the corresponding film layer.

[0061] In a preferred embodiment, a second support structure is further disposed above the first support structure, and the second support structure at least covers a portion of the first support structure. Specifically, refer to... Figure 9The diagram shows a cross-sectional view of the resonator 300, where a cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening in the support structure. Similar to the resonator 100, the resonator 300 includes a substrate 301; a functional layer located on the substrate 301, the functional layer including at least a bottom electrode 303, a piezoelectric layer 304, and a top electrode 305, the piezoelectric layer 304 being located between the bottom electrode 303 and the top electrode 305; a cavity 302 between the bottom electrode 303 and the substrate 301; a through-hole on the functional layer, a first support structure 3061 being disposed on at least a portion of the inner sidewall of the through-hole, the first support structure 3061 extending from the bottom electrode 303 along the inner sidewall of the through-hole to the bottom surface of the cavity 302. The main difference from resonator 100 is that a second support structure 3062 is also included above the first support structure 3061. The second support structure 3062 extends from the outside of the top electrode 305 to the surface of the first support structure 3061. At the edge of the effective resonant region, there is a break 308 between the top electrode 305 and the second support structure 3062 to achieve electrical isolation and avoid short circuits between electrodes. The first and second support structures are preferably formed simultaneously with the bottom electrode and the top electrode, respectively. In addition to the technical effects described above, the multi-layered metal stacking improves the conductivity of the bottom electrode, which can reduce the series impedance Rs of the resonator and improve the performance of the resonator. It can be understood that the first and second support structures can be formed from any two layers of the functional layers, and are not limited to the combination of the bottom electrode and the top electrode.

[0062] In specific embodiments, the second support structure and the first support structure can be made of the same material or different materials, depending on actual needs. When the materials of the second support structure and the first support structure are different, the mechanical stability of the functional layer in the resonator can be improved by setting the second support structure.

[0063] In a preferred embodiment, the functional layer may further include one or more of a passivation layer, a support layer, a seed layer, or a temperature compensation layer. Figure 10This is a cross-sectional view of the resonator 400 in another preferred embodiment of the present invention, where the cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening of the support structure. Similar to the resonator 100, the resonator 400 includes a substrate 401; a functional layer located on the substrate 401, the functional layer including at least a bottom electrode 403, a piezoelectric layer 404 and a top electrode 405, the piezoelectric layer 404 being located between the bottom electrode 403 and the top electrode 405; a cavity 402 between the bottom electrode 403 and the substrate 401; and a through-hole on the functional layer, with a first support structure 406 disposed on at least a portion of the inner sidewall of the through-hole. The main difference from the resonator 100 is that the functional layer of the resonator 400 also includes a passivation layer 407 disposed on the top layer, and the first support structure 406 extends from the passivation layer 407 along the inner sidewall of the through-hole to the bottom surface of the cavity 402. The passivation layer 407 can effectively defend the resonator against external environmental erosion. The first support structure 406 can be formed simultaneously with the passivation layer 407, giving the resonator 400 good mechanical strength and temperature stability. It can be understood that if the resonator includes a support layer, a seed layer, or a temperature compensation layer, the support structure can also be formed from one or more of the support layer, seed layer, or temperature compensation layer.

[0064] In specific embodiments, depending on actual needs, the cavity can be disposed on the upper surface of the substrate or embedded in the interior of the substrate to form an above-ground cavity or an underground cavity. Figure 11 This is a cross-sectional view of the resonator 500 in another preferred embodiment of the present invention, where the cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening in the support structure. Similar to the resonator 100, the resonator 500 includes a substrate 501; a functional layer located on the substrate 501, the functional layer including at least a bottom electrode 503, a piezoelectric layer 504, and a top electrode 505, the piezoelectric layer 504 being located between the bottom electrode 503 and the top electrode 505; a cavity 502 being formed between the bottom electrode 503 and the substrate 501; wherein, the functional layer has a through-hole, and a first support structure 506 is provided on at least a portion of the inner sidewall of the through-hole, the first support structure 506 having a bottom that contacts the substrate 501. The main difference from the resonator 100 is that the surface of the substrate 501 is not etched, and the cavity 502 is entirely located above the substrate 501, forming a ground-type cavity structure.

[0065] Figures 12-14 This is a cross-sectional view of the resonator in another preferred embodiment of the present invention, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through the two non-adjacent sides of the opening in the support structure. Figures 12-14 The resonators shown are all ground-type cavity structures, and have a first support structure extending from one of the bottom electrode, piezoelectric layer or top electrode along the inner wall of the through hole to the bottom surface of the cavity, or have a first support structure and a second support structure extending from different layers in the functional layer.

[0066] Specifically, Figure 12 The structure of the resonator 600 shown is similar to that of the resonator 200. It includes a substrate 601, a bottom electrode 603, a piezoelectric layer 604, a top electrode 605, a cavity 602, and a first support structure 606. The main difference between the resonator 600 and the resonator 200 is that the cavity 602 of the resonator 600 is located entirely above the substrate 601, forming a ground-type cavity structure.

[0067] Specifically, Figure 13 The resonator 700 shown has a structure similar to that of the resonator 300. It includes a substrate 701, a bottom electrode 703, a piezoelectric layer 704, a top electrode 705, a cavity 702, a first support structure 7061, and a second support structure 7062. The first support structure 7061 extends from the bottom electrode 703 along the inner wall of the through hole to the bottom surface of the cavity 702. The second support structure 7062 above the first support structure 7061 extends from the outer side of the top electrode 705 to the surface of the first support structure 7061. The difference from the resonator 300 is that the cavity 702 of the resonator 700 is located entirely above the substrate 701, forming a ground-type cavity structure.

[0068] Specifically, Figure 14 The structure of the resonator 800 shown is similar to that of the resonator 400. It includes a substrate 801, a bottom electrode 803, a piezoelectric layer 804, a top electrode 805, a cavity 802, and a first support structure 806. The functional layer also includes a passivation layer 807 disposed on the top. The first support structure 806 extends from the passivation layer 807 along the inner sidewall of the through hole to the bottom surface of the cavity 802. The difference from the resonator 400 is that the cavity 802 of the resonator 800 is located entirely above the substrate 801, forming a ground-type cavity structure.

[0069] In a preferred embodiment, since the support structure provides support for the functional layer, the support effect of the cavity is enhanced, which can prevent the central region of the resonance from collapsing and sticking to the substrate. Compared with the cavity height of 2-3 μm in existing resonators, the height of the resonator cavity in this embodiment can be less than 2 μm. Preferably, the height range of the cavity is 0.5-1.5 μm, which reduces the sacrificial material used for filling and further reduces the process cost. At the same time, the cavity height is reduced, the heat dissipation path of the resonator is shortened, which further improves the heat dissipation effect.

[0070] According to a second aspect of the present invention, in a specific embodiment, the method for manufacturing a resonator includes the following steps:

[0071] A substrate is provided; a cavity is formed on the substrate; a functional layer is formed on the cavity and the substrate, and a via is formed in the functional layer during the formation of the functional layer, the functional layer including at least a bottom electrode, a piezoelectric layer and a top electrode; wherein a first support structure is formed on at least a portion of the inner sidewall of the via, the first support structure extending from the inner sidewall of the via to the bottom surface of the cavity.

[0072] In a preferred embodiment, the first support structure and the functional layer are integrally formed during the manufacturing process of the resonator.

[0073] In a further preferred embodiment, the first support structure is formed in the same layer as the top electrode, and there is a break between the first support structure and the top electrode to achieve electrical isolation.

[0074] Figures 15a-15i This is a schematic diagram of the manufacturing process of a resonator 900 in a specific embodiment of the present invention. The functional layer of the resonator 900 has a through hole, and a first support structure is formed in the same layer as the top electrode and extends from the inner sidewall of the through hole to the bottom surface of the cavity. The manufacturing process specifically includes:

[0075] like Figure 15a As shown, a substrate 901 is provided, and the substrate 901 is etched to form a cavity 902; the material of the substrate 901 is preferably Si, sapphire, spinel, etc.

[0076] like Figure 15b As shown, a sacrificial material is deposited on the substrate 901, and the sacrificial material is patterned to form a sacrificial layer 902'. Optionally, the sacrificial layer 902' is subjected to CMP (chemical mechanical polishing) to make its central region recessed downward to expose part of the substrate 901. The preferred material for the sacrificial layer 902' is PSG (P-doped SiO2).

[0077] like Figure 15c As shown, a bottom electrode layer 903 is formed on the sacrificial layer 902' by processes such as sputtering, photolithography and etching. The preferred material is molybdenum (Mo), and other optional materials are metals or alloys such as gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co) or aluminum (Al).

[0078] like Figure 15d As shown, by etching the bottom electrode 903, the central region of the bottom electrode 903 is removed to expose the substrate of the central region and part of the edge horizontal surface of the sacrificial layer 902'.

[0079] like Figure 15eAs shown, the piezoelectric layer 904 is further grown. The preferred material for the piezoelectric layer 904 is aluminum nitride (AlN), but zinc oxide (ZnO), zinc sulfide (ZnS), lithium tantalate (LiTaO3), cadmium sulfide (CdS), lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), etc. can also be selected.

[0080] like Figure 15f As shown, the piezoelectric layer 904 is etched until the substrate 901 in the central region and the sacrificial layer 902' and part of the edge horizontal surface of the bottom electrode 903 are exposed.

[0081] like Figure 15g As shown, the top electrode 905 and the first support structure 906 are fabricated simultaneously by sputtering process. The preferred material is molybdenum (Mo), and other optional materials are metals or alloys such as gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co) or aluminum (Al).

[0082] like Figure 15h As shown, at the position corresponding to the edge of the effective resonant region, the top electrode 905 is etched to form a fracture 908; this fracture 908 effectively physically separates the top electrode 905 from the first support structure 906, ultimately achieving electrical insulation between them. Those skilled in the art will understand that the fracture, viewed from above, can be referred to as a groove.

[0083] like Figure 15i As shown, the sacrificial layer 902' is released to form a cavity 902.

[0084] Although the steps of the method are listed in a certain order, those skilled in the art will understand that the steps can be performed in a different order than described above, that is, in reverse or in parallel. Detailed descriptions of each structural layer are provided in the device description and will not be repeated here.

[0085] The resonator proposed in this invention features a through-hole formed on the functional layer, addressing the technical problem of excessively high temperature in the central region of the resonator. A support structure is provided on at least a portion of the inner sidewall of the through-hole, resolving the technical problem of poor mechanical stability of the resonator. The support structure has a bottom that contacts the substrate, addressing the technical problem of slow heat dissipation of the resonator. The stepped shape of the inner sidewall of the through-hole reduces transverse wave leakage of the resonator. This structure can meet the performance requirements of high-frequency and high-power devices, enhance the reliability of the resonator, and improve its long-term operating life.

[0086] The specific embodiments of this application have been described above, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A resonator, comprising: Substrate; A functional layer located on the substrate, the functional layer comprising at least a bottom electrode, a piezoelectric layer and a top electrode, wherein the piezoelectric layer is located between the bottom electrode and the top electrode; There is a cavity between the bottom electrode and the substrate; The functional layer has a through-hole located in the central region of the resonator. The through-hole penetrates the functional layer to form an annular effective resonant region around the through-hole. At least a portion of the inner sidewall of the through-hole is provided with a first support structure, which has a bottom that contacts the substrate.

2. The resonator according to claim 1, characterized in that, The first support structure extends from one of the bottom electrode, piezoelectric layer, or top electrode along the inner wall of the through hole to the bottom surface of the cavity.

3. The resonator according to claim 1, characterized in that, The first support structure extends to the bottom of the through hole and at least covers the portion of the bottom surface of the cavity corresponding to the bottom of the through hole.

4. The resonator according to claim 1, characterized in that, The inner wall of the through-hole in the functional layer is vertical, inclined, or stepped.

5. The resonator according to claim 4, characterized in that, The inner wall of the through-hole of the functional layer is stepped, and the first support structure extends along the through-hole from a portion of the upper surface of one of the bottom electrode, piezoelectric layer or top electrode to the bottom surface of the cavity.

6. The resonator according to claim 1, characterized in that, The first support structure completely covers the inner wall of the through hole, or is distributed discontinuously along the inner wall of the through hole.

7. The resonator according to claim 1, characterized in that, The projection shape of the through hole on the substrate is circular, elliptical, or polygonal.

8. The resonator according to claim 1, characterized in that, The first support structure is made of the same material as the bottom electrode, piezoelectric layer, or top electrode.

9. The resonator according to any one of claims 1-8, characterized in that, Above the first support structure is a second support structure, which at least partially covers the first support structure.

10. The resonator according to claim 9, characterized in that, The second support structure extends from the outside of one of the bottom electrode, piezoelectric layer, or top electrode to at least a portion of the surface of the first support structure to cover a portion of the first support structure.

11. The resonator according to claim 9, characterized in that, The second support structure is made of the same material as the first support structure.

12. The resonator according to claim 9, characterized in that, The second support structure is made of a different material than the first support structure.

13. The resonator according to any one of claims 1-8, characterized in that, The functional layer also includes one or more of a passivation layer, a support layer, a seed layer, or a temperature compensation layer.

14. The resonator according to any one of claims 1-8, characterized in that, The cavity is located on the upper surface of the substrate or embedded inside the substrate.

15. The resonator according to any one of claims 1-8, characterized in that, The height of the cavity is less than 2 μm.

16. The resonator according to claim 15, characterized in that, The height of the cavity is 0.5-1.5 μm.

17. A method for manufacturing a resonator, comprising the following steps: Provide substrate; A cavity is formed on the substrate; A functional layer is formed on the cavity and the substrate, and a via is formed in the functional layer during the formation of the functional layer. The functional layer includes at least a bottom electrode, a piezoelectric layer and a top electrode. A first support structure is formed on at least a portion of the inner sidewall of the through hole, the through hole being located in the central region of the resonator, the through hole penetrating the functional layer to form an annular effective resonant region surrounding the through hole, and the first support structure extending from the inner sidewall of the through hole to the bottom surface of the cavity.

18. The method for manufacturing a resonator according to claim 17, characterized in that, The first support structure is integrally formed with the functional layer.

19. The method for manufacturing a resonator according to claim 18, characterized in that, The first support structure is formed in the same layer as the top electrode, and there is a break between the first support structure and the top electrode to achieve electrical isolation.

20. A filter, characterized in that, Includes the resonator according to any one of claims 1-16.

21. An electronic device, characterized in that, Includes the resonator according to any one of claims 1-16.

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