Bulk acoustic wave resonance device and method for forming bulk acoustic wave resonance device

Abstract

A bulk acoustic wave resonance device and a method for forming the bulk acoustic wave resonance device. The structure of the device comprises: a piezoelectric layer, comprising a resonance region, a first non-resonance region and a second non-resonance region; a first electrode layer, located on first sides of the resonance region and the first non-resonance region; a first passivation layer, located on the second non-resonance region, and the top and the edge side walls of the first electrode layer; a second electrode layer, located on second sides of the resonance region and the second non-resonance region; a second passivation layer, located on the first non-resonance region, and the top and the edge side walls of the second electrode layer; and a first metal layer located on the first side, or a second metal layer located on the second side. The first metal layer is located on the surface of the first passivation layer on the resonance region and the second non-resonance region, or is located on the surface of the first passivation layer on the first non-resonance region and the second non-resonance region. The second metal layer is located on the surface of the second passivation layer on the resonance region and the first non-resonance region, or is located on the surface of the second passivation layer on the first non-resonance region and the second non-resonance region. The performance of the bulk acoustic wave resonance device is improved.

Description

Bulk acoustic wave resonator device and method for forming the same

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 7, 2023, with application number 202311667199.9 and invention name “Bulk Acoustic Wave Resonance Device and Method for Forming Bulk Acoustic Wave Resonance Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of communications, and in particular to a bulk acoustic wave resonator device and a method for forming the bulk acoustic wave resonator device. Background Art

[0003] The radio frequency (RF) front-end chips for wireless communication devices include power amplifiers, antenna switches, RF filters, multiplexers, and low-noise amplifiers. RF filters include piezoelectric surface acoustic wave (SAW) filters, piezoelectric bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, and integrated passive device (IPD) filters.

[0004] As wireless communication technology evolves, more and more frequency bands are being used. Simultaneously, with the application of frequency-overlapping technologies like carrier aggregation, mutual interference between wireless frequency bands is becoming increasingly severe. High-performance piezoelectric bulk acoustic wave (BAW) filter technology can address this inter-band interference problem. With the advent of 5G, wireless mobile networks are introducing higher frequency bands, and currently, only piezoelectric BAW filter technology can address this high-frequency filtering issue.

[0005] Existing piezoelectric bulk acoustic wave filters still need to be improved. Summary of the Invention

[0006] The present invention provides a bulk acoustic wave resonator device and a method for forming the bulk acoustic wave resonator device, so as to improve the existing piezoelectric bulk acoustic wave filter.

[0007] In order to solve the above technical problems, the technical solution of the present invention provides a bulk acoustic wave resonance device, comprising: a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to the surface of the piezoelectric layer, the piezoelectric layer comprising a resonance region and a first non-resonance region and a second non-resonance region adjacent to the resonance region, the first non-resonance region and the second non-resonance region being separate from each other; a first electrode layer, the first electrode layer being located on the first side surface of the resonance region and the first side surface of the first non-resonance region; a first passivation layer, the first passivation layer being located on the first side surface of the second non-resonance region, the top surface of the first electrode layer and the edge sidewall surface of the first electrode layer; a second electrode layer, the second electrode layer being located on the second side surface of the piezoelectric layer, the second electrode layer being located on the second side surface of the resonance region and a portion of the surface of the second side of the second non-resonance region; a second passivation layer, the second passivation layer being located on The second side surface of the first non-resonance region, the top surface of the second electrode layer, and the edge sidewall surface of the second electrode layer; the first metal layer located on the first side, or the second metal layer located on the second side, the first metal layer is located on the first passivation layer surface on the resonance region and the second non-resonance region, or the first metal layer is located on the first passivation layer surface on the first non-resonance region and the second non-resonance region, the first metal layer, the first passivation layer, and the first electrode layer constitute a first capacitor, the first metal layer is electrically connected to the second electrode layer, the second metal layer is located on the second passivation layer surface on the resonance region and the first non-resonance region, or the second metal layer is located on the second passivation layer surface on the first non-resonance region and the second non-resonance region, the second metal layer, the second passivation layer, and the second electrode layer constitute a second capacitor, and the second metal layer is electrically connected to the first electrode layer.

[0008] Optionally, when the first metal layer is located on the first side, it also includes: a first through hole located in the second non-resonant region and the first passivation layer, the first through hole exposing the surface of the first metal layer; and a first connecting structure located in the first through hole, the first connecting structure electrically connecting the first metal layer and the second electrode layer.

[0009] Optionally, the first connection structure includes: a first conductive layer located on the side wall surface of the first through hole and the surface of the first metal layer, the first conductive layer is connected to the second electrode layer; and a first connection layer embedded in the first through hole and electrically connected to the first conductive layer.

[0010] Optionally, the material of the first conductive layer is the same as that of the second electrode layer.

[0011] Optionally, the material of the first connecting layer includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0012] Optionally, when the second metal layer is located on the second side, it further includes: a second through hole located in the first non-resonant region and the second passivation layer, the bottom of the second through hole exposing the surface of the first electrode layer; and a second connection structure located in the second through hole, the second connection structure electrically connecting the second metal layer and the first electrode layer.

[0013] Optionally, the second connection structure includes: a second conductive layer located on the sidewall surface of the second through hole and the surface of the first electrode layer; and a second connection layer embedded in the second through hole and electrically connected to the second conductive layer.

[0014] Optionally, the second connection structure further includes: a third conductive layer located between the second conductive layer and the second connection layer.

[0015] Optionally, the material of the second conductive layer is the same as that of the second electrode layer; and the material of the third conductive layer is the same as that of the second metal layer.

[0016] Optionally, the second metal layer is located on a portion of the surface of the second passivation layer on the second non-resonant region.

[0017] Optionally, the material of the second connecting layer includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0018] Optionally, the projection pattern of the resonance zone is a regular hexagon, and when the first non-resonance zone and the second non-resonance zone are respectively connected to two opposite sides of the regular hexagon, the first metal layer is located on the resonance zone and the surface of the first passivation layer on the second non-resonance zone, or the second metal layer is located on the first non-resonance zone and the surface of the second passivation layer on the second non-resonance zone; when the first non-resonance zone and the second non-resonance zone are respectively connected to two adjacent sides of the regular hexagon, the first metal layer is located on the first non-resonance zone and the surface of the first passivation layer on the second non-resonance zone, or the second metal layer is located on the resonance zone and the surface of the second passivation layer on the first non-resonance zone.

[0019] Optionally, the thickness of the first passivation layer is smaller than the thickness of the piezoelectric layer; and the thickness of the second passivation layer is smaller than the thickness of the piezoelectric layer.

[0020] Correspondingly, the technical solution of the present invention also provides a method for forming a bulk acoustic wave resonator device, including: providing a piezoelectric layer, the piezoelectric layer including a first side and a second side opposite to each other in a direction perpendicular to the surface of the piezoelectric layer, the piezoelectric layer including a resonant region and a first non-resonant region and a second non-resonant region adjacent to the resonant region, the first non-resonant region and the second non-resonant region being separate from each other; forming a first electrode layer and a first passivation layer located on the first side of the piezoelectric layer, the first electrode layer being located on the first side surface of the resonant region and the first side surface of the first non-resonant region, the first passivation layer being located on the first side surface of the second non-resonant region, the top surface of the first electrode layer and the edge sidewall surface of the first electrode layer; forming a second electrode layer and a second passivation layer located on the second side of the piezoelectric layer, the second electrode layer being located on the second side surface of the piezoelectric layer, the second electrode layer being located on the second side surface of the resonant region and a portion of the surface of the second side of the second non-resonant region. surface, the second passivation layer is located on the second side surface of the first non-resonance region, the top surface of the second electrode layer and the edge sidewall surface of the second electrode layer; a first metal layer is formed on the first side, or a second metal layer is formed on the second side, the first metal layer is located on the first passivation layer surface on the resonant region and the second non-resonance region, or the first metal layer is located on the first passivation layer surface on the first non-resonance region and the second non-resonance region, the first metal layer, the first passivation layer and the first electrode layer constitute a first capacitor, the first metal layer is electrically connected to the second electrode layer, the second metal layer is located on the second passivation layer surface on the resonant region and the first non-resonance region, or the second metal layer is located on the second passivation layer surface on the first non-resonance region and the second non-resonance region, the second metal layer, the second passivation layer and the second electrode layer constitute a second capacitor, and the second metal layer is electrically connected to the first electrode layer.

[0021] Optionally, when the first metal layer is located on the first side, the method of electrically connecting the first metal layer and the second electrode layer includes: forming a first through hole located in the second non-resonant region and the first passivation layer, the first through hole exposing the surface of the first metal layer; forming a first connection structure in the first through hole, the first connection structure electrically connecting the first metal layer and the second electrode layer.

[0022] Optionally, the first connection structure includes: a first conductive layer located on the side wall surface of the first through hole and the surface of the first metal layer, the first conductive layer is connected to the second electrode layer; a first connection layer embedded in the first through hole and electrically connected to the first conductive layer; the first conductive layer and the second electrode layer are formed simultaneously.

[0023] Optionally, when the second metal layer is located on the second side, the method of electrically connecting the second metal layer and the first electrode layer includes: forming a second through hole located in the first non-resonant region and the second passivation layer, the second through hole exposing the surface of the first electrode layer; forming a second connection structure in the second through hole, the second connection structure electrically connecting the second metal layer and the first electrode layer.

[0024] Optionally, the second connection structure includes: a second conductive layer located on the sidewall surface of the second through hole and the surface of the first electrode layer; and a second connection layer embedded in the second through hole and electrically connected to the second conductive layer.

[0025] Optionally, the second connection structure further includes: a third conductive layer located between the second conductive layer and the second connection layer.

[0026] Optionally, the second conductive layer and the second electrode layer are formed simultaneously; and the third conductive layer and the second metal layer are formed simultaneously.

[0027] Optionally, the projection pattern of the resonance zone is a regular hexagon, and when the first non-resonance zone and the second non-resonance zone are respectively connected to two opposite sides of the regular hexagon, the first metal layer is located on the resonance zone and the surface of the first passivation layer on the second non-resonance zone, or the second metal layer is located on the first non-resonance zone and the surface of the second passivation layer on the second non-resonance zone; when the first non-resonance zone and the second non-resonance zone are respectively connected to two adjacent sides of the regular hexagon, the first metal layer is located on the first non-resonance zone and the surface of the first passivation layer on the second non-resonance zone, or the second metal layer is located on the resonance zone and the surface of the second passivation layer on the first non-resonance zone.

[0028] Correspondingly, the technical solution of the present invention also provides a bulk acoustic wave resonance device, comprising: a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to the surface of the piezoelectric layer, the piezoelectric layer comprising a resonance region and a first non-resonance region, a second non-resonance region and a third non-resonance region adjacent to the resonance region, the first non-resonance region, the second non-resonance region and the third non-resonance region being separate from each other; a first electrode layer, the first electrode layer being located on the first side surface of the resonance region and the first side surface of the first non-resonance region; a first passivation layer being located on the first side surface of the second non-resonance region, the first side surface of the third non-resonance region, the top surface of the first electrode layer and the edge sidewall surface of the first electrode layer; a second electrode layer, the second electrode layer being located on the second side surface of the piezoelectric layer, the second electrode layer being located on the second side surface of the resonance region and the second side surface of the second non-resonance region Two side surfaces; a second passivation layer, the second passivation layer is located on the second side surface of the first non-resonance region, the second side surface of the third non-resonance region, the top surface of the second electrode layer and the edge sidewall surface of the second electrode layer; a first metal layer located on the first side, and a second metal layer located on the second side, the first metal layer is electrically connected to the second metal layer, the first metal layer is located on the first passivation layer surface on the first non-resonance region and the third non-resonance region, the second metal layer is located on the second passivation layer surface on the resonance region and the third non-resonance region, or, the second metal layer is located on the second passivation layer surface on the second non-resonance region and the third non-resonance region; or, the first metal layer is located on the first passivation layer surface on the resonance region and the third non-resonance region, and the second metal layer is located on the second passivation layer surface on the resonance region and the third non-resonance region.

[0029] Optionally, it also includes: a third through hole located in the second passivation layer, in the third non-resonant zone and in the first passivation layer, the third through hole exposing the surface of the first metal layer; a third connection structure located in the third through hole, the third connection structure electrically connecting the first metal layer and the second metal layer.

[0030] Optionally, the third connection structure includes: a fourth conductive layer located on the side wall surface of the third through hole and the surface of the first metal layer, the fourth conductive layer being connected to the second metal layer; and a third connection layer embedded in the third through hole and electrically connected to the fourth conductive layer.

[0031] Optionally, the material of the fourth conductive layer is the same as that of the second metal layer.

[0032] Optionally, the projection pattern of the resonant region is a regular hexagon, and the first non-resonant region, the second non-resonant region and the third non-resonant region are respectively connected to one side of the regular hexagon.

[0033] Optionally, the second non-resonant zone and the third non-resonant zone are respectively connected to two opposite sides of the regular hexagon. When the first non-resonant zone is adjacent to the second non-resonant zone, the first metal layer is located on the surface of the first passivation layer on the resonant zone and the third non-resonant zone, and the second metal layer is located on the surface of the second passivation layer on the resonant zone and the second non-resonant zone.

[0034] Optionally, the first non-resonant zone, the second non-resonant zone and the third non-resonant zone are respectively connected to three continuous sides of the regular hexagon; when the first non-resonant zone is located between the second non-resonant zone and the third non-resonant zone, the first metal layer is located on the first passivation layer surface on the first non-resonant zone and the third non-resonant zone, and the second metal layer is located on the second passivation layer surface on the resonant zone and the third non-resonant zone; when the third non-resonant zone is located between the second non-resonant zone and the first non-resonant zone, the first metal layer is located on the first passivation layer surface on the first non-resonant zone and the third non-resonant zone, and the second metal layer is located on the second non-resonant zone and the third non-resonant zone.

[0035] Optionally, the thickness of the first passivation layer is smaller than the thickness of the piezoelectric layer; and the thickness of the second passivation layer is smaller than the thickness of the piezoelectric layer.

[0036] Correspondingly, the technical solution of the present invention also provides a method for forming a bulk acoustic wave resonator device, comprising: providing a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to the surface of the piezoelectric layer, the piezoelectric layer comprising a resonant region and a first non-resonant region, a second non-resonant region and a third non-resonant region adjacent to the resonant region, the first non-resonant region, the second non-resonant region and the third non-resonant region being separate from each other; forming a first electrode layer and a first passivation layer on the first side of the piezoelectric layer, the first electrode layer being located on the first side surface of the resonant region and the first side surface of the first non-resonant region, the first passivation layer being located on the first side surface of the second non-resonant region, the top surface of the first electrode layer and the edge sidewall surface of the first electrode layer; forming a second electrode layer and a second passivation layer on the second side of the piezoelectric layer, the second electrode layer being located on the second side surface of the piezoelectric layer, the second The electrode layer is located on the second side surface of the resonant region and the second side surface of the second non-resonant region, and the second passivation layer is located on the second side surface of the first non-resonant region, the top surface of the second electrode layer, and the edge sidewall surface of the second electrode layer; a first metal layer is formed on the first side, and a second metal layer is formed on the second side, the first metal layer is electrically connected to the second metal layer, the first metal layer is located on the first passivation layer surface on the first non-resonant region and the third non-resonant region, the second metal layer is located on the second passivation layer surface on the resonant region and the third non-resonant region, or, the second metal layer is located on the second passivation layer surface on the second non-resonant region and the third non-resonant region; or, the first metal layer is located on the first passivation layer surface on the resonant region and the third non-resonant region, and the second metal layer is located on the second passivation layer surface on the resonant region and the third non-resonant region.

[0037] Optionally, the method of electrically connecting the first metal layer and the second metal layer includes: forming a third through hole in the second passivation layer, in the third non-resonant zone and in the first passivation layer, wherein the third through hole exposes the surface of the first metal layer; and forming a third connection structure in the third through hole, wherein the third connection structure electrically connects the first metal layer and the second metal layer.

[0038] Optionally, the third connection structure includes: a fourth conductive layer located on the side wall surface of the third through hole and the surface of the first metal layer, the fourth conductive layer being connected to the second metal layer; a third connection layer embedded in the third through hole and electrically connected to the fourth conductive layer; the fourth conductive layer and the second metal layer are formed at the same time.

[0039] Optionally, the projection pattern of the resonant region is a regular hexagon, and the first non-resonant region, the second non-resonant region and the third non-resonant region are respectively connected to one side of the regular hexagon.

[0040] Optionally, the second non-resonant zone and the third non-resonant zone are respectively connected to two opposite sides of the regular hexagon. When the first non-resonant zone is adjacent to the second non-resonant zone, the first metal layer is located on the surface of the first passivation layer on the resonant zone and the third non-resonant zone, and the second metal layer is located on the surface of the second passivation layer on the resonant zone and the second non-resonant zone.

[0041] Optionally, the first non-resonant zone, the second non-resonant zone and the third non-resonant zone are respectively connected to three continuous sides of the regular hexagon; when the first non-resonant zone is located between the second non-resonant zone and the third non-resonant zone, the first metal layer is located on the first passivation layer surface on the first non-resonant zone and the third non-resonant zone, and the second metal layer is located on the second passivation layer surface on the resonant zone and the third non-resonant zone; when the third non-resonant zone is located between the second non-resonant zone and the first non-resonant zone, the first metal layer is located on the first passivation layer surface on the first non-resonant zone and the third non-resonant zone, and the second metal layer is located on the second non-resonant zone and the third non-resonant zone.

[0042] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0043] The technical solution of the present invention is to make the first electrode layer, the first passivation layer and the first metal layer form a first capacitor, and the second electrode layer, the second passivation layer and the second metal layer form a second capacitor, and connect the first capacitor in parallel with the resonance region, or connect the second capacitor in parallel with the resonance region, or connect the first capacitor and the second capacitor in parallel with the resonance region, so as to meet the purpose of connecting capacitors in parallel on the resonator. The first capacitor and the second capacitor are pure capacitor structures with a double-layer electrode plate and a dielectric layer between the double-layer electrode plates, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit to prevent adjacent interference frequency bands from passing through, thereby achieving the effect of enhancing near-end out-of-band suppression.

[0044] Furthermore, the thickness of the first passivation layer and the second passivation layer is smaller than the thickness of the piezoelectric layer, so that the area of ​​the first capacitor and the second capacitor formed is reduced, and the chip size can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic diagram of the structure of a filter circuit in one embodiment;

[0046] 2 to 6 are schematic structural diagrams of a bulk acoustic wave resonator device forming process according to an embodiment of the present invention;

[0047] 7 and 8 are schematic structural diagrams of a bulk acoustic wave resonator device forming process according to another embodiment of the present invention;

[0048] 9 and 10 are schematic structural diagrams of a bulk acoustic wave resonator device forming process according to another embodiment of the present invention;

[0049] 11 and 12 are structural diagrams showing a process of forming a bulk acoustic wave resonator device according to another embodiment of the present invention;

[0050] 13 and 14 are schematic structural diagrams of a bulk acoustic wave resonator device forming process according to another embodiment of the present invention;

[0051] 15 and 16 are schematic structural diagrams showing a process of forming a bulk acoustic wave resonator device according to another embodiment of the present invention;

[0052] 17 and 18 are schematic structural diagrams showing a process of forming a bulk acoustic wave resonator device according to another embodiment of the present invention;

[0053] FIG19 is a schematic diagram of a partial circuit structure of a bulk acoustic wave resonator device according to one embodiment of the present invention;

[0054] FIG20 is a schematic diagram of a partial circuit structure of a bulk acoustic wave resonator device according to another embodiment of the present invention;

[0055] FIG21 is a schematic diagram of a partial circuit structure of a bulk acoustic wave resonator device in another embodiment of the present invention. DETAILED DESCRIPTION

[0056] As described in the background art, existing piezoelectric bulk acoustic wave filters still need to be improved. This will now be analyzed and explained in conjunction with specific embodiments.

[0057] FIG1 is a schematic diagram of the structure of a filter circuit in one embodiment.

[0058] Referring to Figure 1, the filter comprises a first resonator S1, a second resonator S2, and a third resonator S3 connected in series, and a fourth resonator T1 connected in parallel with the first, second, and third resonators S1, S2, and S3. The larger admittance of the series resonator and the smaller admittance of the parallel resonator form the filter's passband. The minimum admittance of the series resonator and the maximum admittance of the parallel resonator form transmission zeros on either side of the passband. The minimum admittance of the series resonator and the maximum admittance of the parallel resonator together determine the bandwidth of the filter's passband.

[0059] Connecting a capacitor in parallel to the resonator can reduce the electromechanical coupling coefficient of the resonator and increase the Q value (Q p ), which can improve out-of-band suppression and enhance roll-off. As shown in FIG1 , a capacitor C1 is connected in parallel to the first resonator S1.

[0060] However, in traditional FBAR filters, it is not possible to improve filter performance by adding a pure capacitor in parallel to the resonator. Usually, a parallel resonator is used to replace the capacitor. Therefore, the effect of improving out-of-band suppression and enhancing roll-off is not obvious.

[0061] In order to solve the above problems, the technical solution of the present invention provides a bulk acoustic wave resonator device and a method for forming a bulk acoustic wave resonator device, by making the first electrode layer, the first passivation layer and the first metal layer form a first capacitor, and making the second electrode layer, the second passivation layer and the second metal layer form a second capacitor, and the first capacitor is connected in parallel with the resonant region, or the second capacitor is connected in parallel with the resonant region, or the first capacitor and the second capacitor are connected in parallel with the resonant region, so as to meet the purpose of connecting capacitors in parallel on the resonator. The first capacitor and the second capacitor are pure capacitor structures with a double-layer electrode plate and a dielectric layer between the double-layer electrode plate, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the anti-resonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the circuit of the bulk acoustic wave resonator device, so that adjacent interference frequency bands are not easily passed, thereby achieving the effect of enhancing near-end out-of-band suppression.

[0062] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0063] 2 to 6 are schematic structural diagrams of a process for forming a bulk acoustic wave resonator device according to an embodiment of the present invention.

[0064] It should be noted that the terms “surface”, “upper” and “lower” in this specification are used to describe relative positional relationships in space and are not limited to whether they are in direct contact.

[0065] Please refer to Figures 2 and 3, Figure 2 is a top view of the second surface of Figure 3, and Figure 3 is a schematic diagram of the cross-sectional structure of Figure 2 along the section line AOA1 direction, providing a piezoelectric layer 100, the piezoelectric layer 100 including a first side S1 and a second side S2 opposite to each other in a direction perpendicular to the surface of the piezoelectric layer 100, the piezoelectric layer 100 including a resonant region I and a first non-resonant region II and a second non-resonant region III adjacent to the resonant region I, the first non-resonant region II and the second non-resonant region III being separate from each other.

[0066] The material of the piezoelectric layer 100 includes lithium tantalate, lithium niobate, quartz, aluminum nitride, zinc oxide, gallium nitride or lead zirconate titanate piezoelectric ceramics.

[0067] In this embodiment, the projection shape of the resonance region I is a hexagon. The non-resonance region is a region surrounding the resonance region I.

[0068] In this embodiment, the first non-resonance region II and the second non-resonance region III are respectively connected to two adjacent sides of the regular hexagon of the resonance region I.

[0069] In other embodiments, the shape of the resonance region may be rectangular or circular.

[0070] Please refer to Figure 4, which is a structural schematic diagram based on Figure 3. A first electrode layer 101, a first passivation layer 102 and a first metal layer 103 are formed on the first side S1 of the piezoelectric layer 100. The first electrode layer 101 is located on the surface of the first side S1 of the resonant zone I and the surface of the first side S1 of the first non-resonant zone II. The first passivation layer 102 is located on the surface of the first side S1 of the second non-resonant zone III, the top surface of the first electrode layer 101 and the edge sidewall surface of the first electrode layer 101. The first metal layer 103 is located on the surface of the first passivation layer 102 on the first non-resonant zone II and the second non-resonant zone III. The first metal layer 103, the first passivation layer 102 and the first electrode layer 101 constitute a first capacitor.

[0071] The first metal layer 103 is used to suppress the lateral diffusion of the bulk acoustic wave and improve the Q value (Q p ).

[0072] In this embodiment, the thickness of the first passivation layer 102 is smaller than that of the piezoelectric layer 100. Therefore, the first capacitor area formed by the first electrode layer 101, the first metal layer 103 and the first passivation layer 102 is smaller, which can reduce the chip size.

[0073] The material of the first electrode layer 101 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0074] The material of the first metal layer 103 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0075] In this embodiment, the material of the first passivation layer 102 includes silicon oxide.

[0076] The method for forming the first electrode layer 101, the first passivation layer 102 and the first metal layer 103 includes: forming an electrode material layer (not shown) on the first side S1 of the piezoelectric layer 100; removing part of the electrode material layer, and forming the first electrode layer 101 on the surface of the first side S1 of the resonance zone I and the surface of the first side S1 of the first non-resonance zone II; after forming the first electrode layer 101, forming a first passivation layer 102 on the first side S1 of the piezoelectric layer 100, the first passivation layer 102 being located on the surface of the first side S1 of the second non-resonance zone III, the top surface of the first electrode layer 101 and the edge sidewall surface of the first electrode layer 101; after forming the first passivation layer 102, forming a metal material layer (not shown) on the surface of the first passivation layer 102; removing part of the metal material layer, and forming the first metal layer 103 on the surface of the first passivation layer 102 on the first non-resonance zone II and the second non-resonance zone III.

[0077] Please refer to Figure 5. A supporting structure (not shown) and a cavity 104 located within the supporting structure are formed on the first side S1 of the piezoelectric layer 100. The supporting structure is bonded to the first side S1 of the piezoelectric layer 100, and at least the first electrode layer 101 located on the surface of the first side S1 of the resonance zone I is located within the cavity 104.

[0078] The method for forming the cavity 104 includes: forming a sacrificial layer (not shown) on the first metal layer 103 and the first passivation layer 102; forming a first bonding layer (not shown) on the top surface and side wall surface of the sacrificial layer and the surface of the first passivation layer 102; providing a supporting substrate (not shown), the surface of the supporting substrate having a second bonding layer (not shown); bonding the second bonding layer toward the sacrificial layer and the first bonding layer so that the first bonding layer and the second bonding layer are bonded, and the supporting structure includes a supporting substrate, a second bonding layer and a first bonding layer; and subsequently, after forming a second electrode layer and a second passivation layer on the second side S2 of the piezoelectric layer 100, removing the sacrificial layer to form the cavity 104.

[0079] Please refer to Figures 5 and 6, Figure 6 is a top view of the second side S2 of Figure 5, and Figure 5 is a schematic diagram of the cross-sectional structure of Figure 6 along the section line AOA1 direction. A second electrode layer 105 and a second passivation layer 107 are formed on the second side S2 of the piezoelectric layer 100, and the second electrode layer 105 is located on the surface of the second side S2 of the resonance zone I and a portion of the surface of the second side S2 of the second non-resonance zone III. The second passivation layer 107 is located on the surface of the second side S2 of the first non-resonance zone II, the top surface of the second electrode layer 105, and the edge sidewall surface of the second electrode layer 105; a first connection structure is formed in the second non-resonance zone III and in the first passivation layer 102, and the first connection structure electrically connects the first metal layer 103 and the second electrode layer 105.

[0080] The first connection structure includes a first conductive layer 106 and a first connection layer 108 located on a surface of the first conductive layer 106 .

[0081] In this embodiment, the first conductive layer 106 and the second electrode layer 105 are formed simultaneously.

[0082] In other embodiments, the first conductive layer and the second electrode layer may be formed at different times.

[0083] The method for forming the second electrode layer 105, the second passivation layer 106 and the first connection structure includes: forming a first through hole (not shown) in the second non-resonance zone III and in the first passivation layer 102, wherein the first through hole extends from the second side S2 to the first side S1, and the first through hole exposes the surface of the first metal layer 103; forming an electrode material layer (not shown) on the surface of the second side S2 of the piezoelectric layer 100, the sidewall surface and the bottom surface of the first through hole; removing the electrode material layer on the surface of the first non-resonance zone II and a portion of the second non-resonance zone III, and forming an electrode material layer on the surface of the second side S2 of the resonant zone I and the second non-resonance zone III; A second electrode layer 105 is formed on the surfaces of the two sides S2, and a first conductive layer 106 is formed on the side wall surfaces and bottom surfaces of the first through hole, and the first conductive layer 106 is electrically connected to the first metal layer 103; a second passivation layer 107 is formed on the surface of the second side S2 of the first non-resonance zone II, the top surface of the second electrode layer 105, and the edge side wall surfaces of the second electrode layer 105; a first connecting layer 108 is formed in the first through hole, and the first connecting layer 108 is embedded in the first through hole and electrically connected to the first conductive layer 106, and the first connecting structure electrically connects the first metal layer 103 and the second electrode layer 105.

[0084] The first electrode layer 101, the first metal layer 103 and the first passivation layer 102 between the first electrode layer 101 and the first metal layer 103 on the first side S1 of the first non-resonance zone II constitute a first capacitor C1. The first connection structure electrically connects the first metal layer 103 and the second electrode layer 105, that is, the first capacitor C1 is connected in parallel on the resonant zone I, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, so that adjacent interference frequency bands are not easily passed through, thereby achieving the effect of enhanced near-end out-of-band suppression.

[0085] Please refer to FIG. 19 , which is a partial circuit diagram of a bulk acoustic wave resonator device according to an embodiment of the present invention. The first capacitor C1 is connected in parallel to the resonator S1 .

[0086] The material of the first conductive layer 106 is the same as that of the second electrode layer 105. The material of the second electrode layer 105 includes metal or metal nitride; the metal includes one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum, and tantalum; the metal nitride includes one or more of tantalum nitride and titanium nitride.

[0087] The material of the first connection layer 108 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0088] In this embodiment, the material of the second passivation layer 107 includes silicon oxide.

[0089] In other embodiments, the first conductive layer and the second electrode layer are not formed at the same time; the method of electrically connecting the first metal layer and the second electrode layer includes: forming a first through hole in the second non-resonant region, in the second electrode layer, and in the second passivation layer, the first through hole exposing the surface of the first metal layer; forming a first connection structure in the first through hole, the first connection structure electrically connecting the first metal layer and the second electrode layer.

[0090] Accordingly, an embodiment of the present invention further provides a bulk acoustic wave resonance device, which includes:

[0091] Cavity 104;

[0092] A piezoelectric layer 100 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 100 , wherein the cavity 104 is located on the first side S1 of the piezoelectric layer 100 , and the piezoelectric layer 100 includes a resonant region I and a first non-resonant region II and a second non-resonant region III adjacent to the resonant region I, wherein the first non-resonant region II and the second non-resonant region III are separate from each other;

[0093] A first electrode layer 101, at least the first electrode layer 101 located in the resonance zone I is located in the cavity 104, and the first electrode layer 101 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0094] A first passivation layer 102 located on the surface of the first side S1 of the second non-resonance region III, the top surface of the first electrode layer 101 and the edge sidewall surface of the first electrode layer 101;

[0095] a first metal layer 103 located on the first side S1 , wherein the first metal layer 103 is located on the surface of the first passivation layer 102 on the first non-resonance region II and the second non-resonance region III;

[0096] A second electrode layer 105, the second electrode layer 105 is located on the second side S2 surface of the piezoelectric layer 100, the second electrode layer 105 is located on the second side S2 surface of the resonant zone I and the second side S2 surface of the non-resonant zone III, and the first metal layer 103 is electrically connected to the second electrode layer 105;

[0097] The second passivation layer 107 is located on the surface of the second side S2 of the first non-resonance region II, the top surface of the second electrode layer 105 and the edge sidewall surface of the second electrode layer 105 .

[0098] In this embodiment, it also includes: a first through hole located in the second non-resonant region III and in the first passivation layer 102, the first through hole exposing the surface of the first metal layer 103; a first connection structure located in the first through hole, the first connection structure electrically connecting the first metal layer 103 and the second electrode layer 105.

[0099] In this embodiment, the first connection structure includes: a first conductive layer 106 located on the sidewall surface of the first through hole and the surface of the first metal layer 103; and a first connection layer 108 embedded in the first through hole and electrically connected to the first conductive layer 106.

[0100] In this embodiment, the material of the first conductive layer 106 is the same as that of the second electrode layer 105 .

[0101] In this embodiment, the material of the first connection layer 108 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0102] In this embodiment, the material of the first electrode layer 101 and the second electrode layer 105 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0103] In this embodiment, the material of the first metal layer 103 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0104] In this embodiment, the thickness of the first passivation layer 102 is smaller than the thickness of the piezoelectric layer 100 ; the thickness of the second passivation layer 107 is smaller than the thickness of the piezoelectric layer 100 .

[0105] In this embodiment, the material of the first passivation layer 102 and the second passivation layer 107 includes silicon oxide.

[0106] In this embodiment, the material of the piezoelectric layer 100 includes lithium tantalate, lithium niobate, quartz, aluminum nitride, zinc oxide, gallium nitride or lead zirconate titanate piezoelectric ceramic.

[0107] In this embodiment, the projection shape of the resonance region I is a hexagon; the first non-resonance region II and the second non-resonance region III are respectively connected to two adjacent sides of the regular hexagon of the resonance region I.

[0108] 7 and 8 are schematic structural diagrams of a process for forming a bulk acoustic wave resonator device according to another embodiment of the present invention.

[0109] Please refer to FIG7 and FIG8 , FIG7 is a top view of the second side S2 of FIG8 , and FIG8 is a schematic cross-sectional view of the structure along the section line AA1 of FIG7 , the bulk acoustic wave resonator device includes:

[0110] Cavity 204;

[0111] A piezoelectric layer 200 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 200 . The cavity 204 is located on the first side S1 of the piezoelectric layer 200 . The piezoelectric layer 200 includes a resonant region I and a first non-resonant region II and a second non-resonant region III adjacent to the resonant region I. The first non-resonant region II and the second non-resonant region III are separate from each other.

[0112] A first electrode layer 201, at least the first electrode layer 201 located in the resonance zone I is located in the cavity 204, and the first electrode layer 201 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0113] A first passivation layer 202 located on the surface of the first side S1 of the second non-resonance region III, the top surface of the first electrode layer 201 and the edge sidewall surface of the first electrode layer 201;

[0114] a first metal layer 203 located on the first side S1, wherein the first metal layer 203 is located on the surface of the first passivation layer 202 on the resonant region I and the second non-resonant region III;

[0115] A second electrode layer 205, the second electrode layer 205 is located on the second side S2 surface of the piezoelectric layer 200, the second electrode layer 205 is located on the second side S2 surface of the resonant zone I and the second side S2 surface of the non-resonant zone III, and the first metal layer 203 is electrically connected to the second electrode layer 205;

[0116] The second passivation layer 206 is located on the surface of the second side S2 of the first non-resonance region II, the top surface of the second electrode layer 205 , and the edge sidewall surface of the second electrode layer 205 .

[0117] In this embodiment, it also includes: a first through hole located in the second non-resonant region III and in the first passivation layer 202, the first through hole exposing the surface of the first metal layer 203; a first connection structure located in the first through hole, the first connection structure electrically connecting the first metal layer 203 and the second electrode layer 205.

[0118] In this embodiment, the first connection structure includes: a first conductive layer 208 located on the sidewall surface of the first through hole and the surface of the first metal layer 203; and a first connection layer 207 embedded in the first through hole and electrically connected to the first conductive layer 208.

[0119] In this embodiment, the material of the first conductive layer 208 is the same as that of the second electrode layer 205 .

[0120] The difference between the BAW resonator devices in Figures 7 and 8 and the BAW resonator devices in Figures 5 and 6 is that, in this embodiment, the projected shape of the resonance zone I is a hexagon; the first non-resonance zone II and the second non-resonance zone III are respectively connected to the two opposite sides of the regular hexagon of the resonance zone I.

[0121] The first electrode layer 201, the first passivation layer 202 and the first metal layer 203 on the first side S1 of the resonance region I constitute a first capacitor. The first metal layer 203 is electrically connected to the second electrode layer 205, that is, the first capacitor C1 is connected in parallel on the resonance region I, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, making it difficult for adjacent interference frequency bands to pass through, thereby achieving the effect of enhanced near-end out-of-band suppression.

[0122] Please refer to FIG. 5 and FIG. 6 for the formation process of FIG. 7 and FIG. 8 , which will not be described again here.

[0123] 9 and 10 are structural diagrams showing a process of forming a bulk acoustic wave resonator device according to another embodiment of the present invention.

[0124] Please refer to FIG9 and FIG10 , FIG9 is a top view of the second side S2 of FIG10 , and FIG10 is a schematic cross-sectional view of the structure along the section line AOA1 of FIG9 , the bulk acoustic wave resonator device includes:

[0125] Cavity 303;

[0126] A piezoelectric layer 300 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 300. The cavity 303 is located on the first side S1 of the piezoelectric layer 300. The piezoelectric layer 300 includes a resonant region I and a first non-resonant region II and a second non-resonant region III adjacent to the resonant region I. The first non-resonant region II and the second non-resonant region III are separate from each other.

[0127] A first electrode layer 301, at least the first electrode layer 301 located in the resonance zone I is located in the cavity 303, and the first electrode layer 301 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0128] A first passivation layer 302 located on the surface of the first side S1 of the second non-resonance region III, the top surface of the first electrode layer 301 and the edge sidewall surface of the first electrode layer 301;

[0129] A second electrode layer 304, the second electrode layer 304 is located on the second side S2 surface of the piezoelectric layer 300, and the second electrode layer 304 is located on the second side S2 surface of the resonance zone I and the second side S2 surface of the second non-resonance zone III;

[0130] A second passivation layer 305 located on the surface of the second side S2 of the first non-resonance region II, the top surface of the second electrode layer 304 and the edge sidewall surface of the second electrode layer 304;

[0131] A second metal layer 306 is located on the second side S2. The second metal layer 306 is located on the surface of the second passivation layer 305 on the first non-resonance zone II and the second non-resonance zone III. The second metal layer 306, the second passivation layer 305 and the second electrode layer 304 constitute a second capacitor. The second metal layer 306 is electrically connected to the first electrode layer 301.

[0132] In this embodiment, it also includes: a second through hole (not shown) located in the first non-resonant region II and in the second passivation layer 305, the second through hole exposing the surface of the first electrode layer 301; a second connection structure located in the second through hole, the second connection structure electrically connecting the second metal layer 306 and the first electrode layer 301.

[0133] In this embodiment, the second connection structure includes: a second conductive layer 308 located on the sidewall surface of the second through hole and the surface of the first electrode layer; and a second connection layer 307 embedded in the second through hole and electrically connected to the second conductive layer 308 .

[0134] In this embodiment, the second connection structure further includes a third conductive layer (not shown) located between the second conductive layer 308 and the second connection layer 307 .

[0135] In this embodiment, the material of the second conductive layer 308 is formed simultaneously with the second electrode layer 304, and the material of the third conductive layer is formed simultaneously with the second metal layer 306. The method for forming the second electrode layer 304, the second connection structure and the second metal layer 306 includes: forming a second through hole in the first non-resonant region II, wherein the second through hole exposes the surface of the first electrode layer 301; forming an electrode material layer (not shown) on the sidewall surface and bottom surface of the second through hole and the surface of the second side S2 of the piezoelectric layer 300; removing the electrode material layer on the surface of the first non-resonant region II, forming a second electrode layer 304 on the surface of the second side S2 of the resonant region I and the second side S2 of the second non-resonant region III, and forming a second electrode layer 304 on the side of the second through hole. A second conductive layer 308 is formed on the wall surface and the bottom surface; a second passivation layer 305 is formed on the second side S2 surface of the first non-resonance zone II, the top surface of the second electrode layer 304, and the edge side wall surface of the second electrode layer 304; a metal material layer (not shown) is formed on the surface of the second passivation layer 305 and the surface of the second conductive layer 308; the metal material layer on the resonance zone I, part of the first non-resonance zone II, and part of the second non-resonance zone III is removed, and a second metal layer 306 is formed on the surface of the second passivation layer 305 on the first non-resonance zone II and the second non-resonance zone III, and a third conductive layer is formed on the surface of the second conductive layer 308; after the second metal layer 306 is formed, a second connecting layer 307 is formed on the third conductive layer.

[0136] In other embodiments, the third conductive layer may not be formed.

[0137] In other embodiments, the second conductive layer and the second electrode layer may not be formed at the same time, and the third conductive layer and the second metal layer may not be formed at the same time.

[0138] In this embodiment, the material of the second conductive layer 308 and the material of the second electrode layer 304 include metal or metal nitride; the material of the third conductive layer and the material of the second metal layer 306 include metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0139] The material of the second connecting layer includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0140] The second metal layer 306, the second passivation layer 305 and the second electrode layer 304 constitute a second capacitor C2. The second connection structure electrically connects the first electrode layer 301 and the second metal layer 306, that is, the second capacitor C2 is connected in parallel on the resonance area I, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator, reduce the bandwidth between the resonant frequency and the anti-resonant frequency of the bulk acoustic wave resonator, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit to prevent adjacent interference frequency bands from passing through, thereby achieving the effect of enhancing near-end out-of-band suppression.

[0141] In this embodiment, the thickness of the second passivation layer 305 is smaller than that of the piezoelectric layer 300 , so that the first capacitor area formed by the second electrode layer 304 , the second metal layer 306 and the second passivation layer 305 is smaller, which can reduce the chip size.

[0142] In this embodiment, the projection shape of the resonance region I is a hexagon; the first non-resonance region II and the second non-resonance region III are respectively connected to two adjacent sides of the regular hexagon of the resonance region I.

[0143] Please refer to FIG. 20 , which is a partial circuit diagram of a bulk acoustic wave resonator device according to an embodiment of the present invention. The second capacitor C2 is connected in parallel to the resonator S1 .

[0144] 11 and 12 are schematic structural diagrams of a process for forming a bulk acoustic wave resonator device according to another embodiment of the present invention.

[0145] Please refer to FIG11 and FIG12 , FIG11 is a top view of the second side S2 of FIG12 , and FIG12 is a schematic cross-sectional view of FIG11 along the section line AA1 , the bulk acoustic wave resonator device includes:

[0146] Cavity 403;

[0147] A piezoelectric layer 400 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 400. The cavity 403 is located on the first side S1 of the piezoelectric layer 400. The piezoelectric layer 400 includes a resonant region I and a first non-resonant region II and a second non-resonant region III adjacent to the resonant region I. The first non-resonant region II and the second non-resonant region III are separate from each other.

[0148] A first electrode layer 401, at least the first electrode layer 401 on the resonance zone I is located in the cavity 403, and the first electrode layer 401 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0149] A first passivation layer 402 located on the surface of the first side S1 of the second non-resonance region III, the top surface of the first electrode layer 401 and the edge sidewall surface of the first electrode layer 401;

[0150] A second electrode layer 404, the second electrode layer 404 is located on the second side S2 surface of the piezoelectric layer 400, and the second electrode layer 404 is located on the second side S2 surface of the resonance zone I and the second side S2 surface of the second non-resonance zone III;

[0151] A second passivation layer 405 located on the surface of the second side S2 of the first non-resonance region II, the top surface of the second electrode layer 404 and the edge sidewall surface of the second electrode layer 404;

[0152] A second metal layer 406 is located on the first side S2. The second metal layer 406 is located on the surface of the second passivation layer 405 on the resonance zone I and the first non-resonance zone II. The second metal layer 406, the second passivation layer 405 and the second electrode layer 404 constitute a second capacitor. The second metal layer 406 is electrically connected to the first electrode layer 401.

[0153] In this embodiment, the present invention further includes: a second through hole (not shown) located within the first non-resonant region II and within the second passivation layer 305, wherein the second through hole exposes the surface of the first electrode layer 301; a second connection structure located within the second through hole, wherein the second connection structure includes: a second conductive layer 408 located on the sidewall surface of the second through hole and the surface of the first electrode layer; and a second connection layer 407 located on the second conductive layer 408. The second metal layer 406 is electrically connected to the first electrode layer 401 via the second connection structure.

[0154] In this embodiment, the second connection structure further includes: a third conductive layer (not shown) located between the second conductive layer 408 and the second connection layer 407 .

[0155] The difference between the BAW resonator device in Figures 11 and 12 and the BAW resonator device in Figures 9 and 10 is that, in this embodiment, the projected shape of the resonance zone I is a hexagon; the first non-resonance zone II and the second non-resonance zone III are respectively connected to the two opposite sides of the regular hexagon of the resonance zone I.

[0156] The second metal layer 406, the second passivation layer 405 and the second electrode layer 404 constitute a second capacitor. The second connection structure electrically connects the first electrode layer 401 and the second metal layer 406, that is, a second capacitor is connected in parallel on the resonance area I, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the anti-resonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, making it difficult for adjacent interference frequency bands to pass through, thereby achieving the effect of enhanced near-end out-of-band suppression.

[0157] Please refer to FIG9 and FIG10 for the formation process of FIG11 and FIG12, and will not be repeated here.

[0158] 13 and 14 are schematic structural diagrams of a process for forming a bulk acoustic wave resonator device according to another embodiment of the present invention.

[0159] Please refer to FIG13 and FIG14 , FIG13 is a top view of the second side S2 of FIG14 , and FIG14 is a schematic cross-sectional view of FIG13 along the section line AA1 , the bulk acoustic wave resonator device includes:

[0160] Cavity 504;

[0161] A piezoelectric layer 500 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 500. The cavity 504 is located on the first side S1 of the piezoelectric layer 500. The piezoelectric layer 500 includes a resonant region I and a first non-resonant region II, a second non-resonant region III, and a third non-resonant region IV adjacent to the resonant region I. The first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are separate from each other.

[0162] A first electrode layer 501, at least the first electrode layer 501 on the resonance zone I is located in the cavity 504, and the first electrode layer 501 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0163] a first passivation layer 502 located on the first side S1 surface of the second non-resonance region III, the first side S1 surface of the third non-resonance region IV, the top surface of the first electrode layer 501 and the edge sidewall surface of the first electrode layer 501;

[0164] A second electrode layer 505, the second electrode layer 505 is located on the second side S2 surface of the piezoelectric layer 500, and the second electrode layer 505 is located on the second side S2 surface of the resonance zone I and the second side S2 surface of the non-resonance zone III;

[0165] a second passivation layer 506 located on the second side S2 surface of the first non-resonance region II, the second side S2 surface of the third non-resonance region IV, the top surface of the second electrode layer 505, and the edge sidewall surface of the second electrode layer 505;

[0166] A first metal layer 503 located on the first side S1 and a second metal layer 507 located on the second side S2, wherein the first metal layer 503 and the second metal layer 507 are electrically connected.

[0167] The first metal layer 503 is located on the surface of the first passivation layer 502 on the resonance zone I and the third non-resonance zone IV, and the second metal layer 507 is located on the surface of the second passivation layer 506 on the resonance zone I and the third non-resonance zone IV.

[0168] In this embodiment, the projection pattern of the resonant region I is a regular hexagon, and the first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are respectively connected to one side of the regular hexagon.

[0169] In this embodiment, the second non-resonance region III and the third non-resonance region IV are respectively connected to two opposite sides of the regular hexagon, and the first non-resonance region II is adjacent to the second non-resonance region III.

[0170] In this embodiment, it also includes: a third through hole (not shown) located in the third non-resonant zone IV, in the second passivation layer 506 and in the first passivation layer 502, wherein the third through hole exposes the surface of the first metal layer 503; and a third connection structure located in the third through hole, wherein the third connection structure electrically connects the first metal layer 503 and the second metal layer 507.

[0171] In this embodiment, the third connection structure includes: a fourth conductive layer 509 located on the side wall surface of the third through hole and the surface of the first metal layer 503, and the fourth conductive layer 509 is connected to the second metal layer 507; and a third connection layer 508 embedded in the third through hole and electrically connected to the fourth conductive layer 509.

[0172] In this embodiment, the fourth conductive layer 509 is formed simultaneously with the second metal layer 507. The material of the fourth conductive layer 509 is the same as that of the second metal layer 507.

[0173] In another embodiment, the third connection structure further includes: a fifth conductive layer (not shown) located between the fourth conductive layer and the third connection layer. The fourth conductive layer is formed simultaneously with the second electrode layer and is made of the same material as the second electrode layer; the fifth conductive layer is formed simultaneously with the second metal layer and is made of the same material as the second metal layer.

[0174] The process of forming the third connection structure, the second electrode layer 505 and the second metal layer 507 is described in detail in FIG9 and FIG10 , and will not be further described here.

[0175] In this embodiment, the material of the third connection layer 508 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0176] The first electrode layer 501, the first passivation layer 502 and the first metal layer 503 on the resonance region I constitute a first capacitor C1, the second electrode layer 505, the second passivation layer 506 and the second metal layer 507 on the resonance region I constitute a second capacitor C2, and the third connection structure electrically connects the first metal layer 503 and the second metal layer 507, that is, the first capacitor C1 and the second capacitor C2 are connected in parallel on the resonance region I, and the first capacitor C1 and the second capacitor C2 are connected in series, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, so that adjacent interference frequency bands are not easily passed through, thereby achieving the effect of enhancing near-end out-of-band suppression.

[0177] Please refer to Figure 21, which is a partial circuit diagram of the bulk acoustic wave resonator device in an embodiment of the present invention. The first capacitor C1 and the second capacitor C2 are connected in series, and the first capacitor C1 and the second capacitor C2 are connected in parallel to the resonator S1.

[0178] For the formation process of FIG. 13 and FIG. 14 , please refer to FIG. 9 and FIG. 10 , FIG. 11 and FIG. 12 , which will not be described in detail here.

[0179] 15 and 16 are schematic structural diagrams of a process for forming a bulk acoustic wave resonator device according to another embodiment of the present invention.

[0180] Please refer to FIG15 and FIG16 , FIG15 is a top view of the second side S2 of FIG16 , and FIG16 is a schematic cross-sectional view of the structure along the section line AOA1 of FIG15 , the bulk acoustic wave resonator device includes:

[0181] Cavity 604;

[0182] A piezoelectric layer 600 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 600. The cavity 604 is located on the first side S1 of the piezoelectric layer 600. The piezoelectric layer 600 includes a resonant region I and a first non-resonant region II, a second non-resonant region III, and a third non-resonant region IV adjacent to the resonant region I. The first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are separate from each other.

[0183] A first electrode layer 601, at least the first electrode layer 601 on the resonance zone I is located in the cavity 604, and the first electrode layer 601 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0184] A first passivation layer 602 located on the first side S1 surface of the second non-resonance region III, the first side S1 surface of the third non-resonance region IV, the top surface of the first electrode layer 601 and the edge sidewall surface of the first electrode layer 601;

[0185] A second electrode layer 605, the second electrode layer 605 is located on the second side S2 surface of the piezoelectric layer 600, and the second electrode layer 605 is located on the second side S2 surface of the resonance zone I and the second side S2 surface of the second non-resonance zone III;

[0186] A second passivation layer 606 located on the second side S2 surface of the first non-resonance region II, the second side S2 surface of the third non-resonance region IV, the top surface of the second electrode layer 605, and the edge sidewall surface of the second electrode layer 605;

[0187] A first metal layer 603 located on the first side S1 and a second metal layer 607 located on the second side S2, wherein the first metal layer 603 and the second metal layer 607 are electrically connected.

[0188] The first metal layer 603 is located on the surface of the first passivation layer 602 on the first non-resonance zone II and the third non-resonance zone IV. The second metal layer 607 is located on the surface of the second passivation layer 606 on the resonance zone I and the third non-resonance zone IV.

[0189] In this embodiment, the projection pattern of the resonant region I is a regular hexagon, and the first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are respectively connected to one side of the regular hexagon.

[0190] In this embodiment, the first non-resonance region II, the second non-resonance region III and the third non-resonance region IV are respectively connected to three consecutive sides of the regular hexagon, and the first non-resonance region II is located between the second non-resonance region III and the third non-resonance region IV.

[0191] In this embodiment, it also includes: a third through hole (not shown) located in the third non-resonant zone IV, in the second passivation layer 606 and in the first passivation layer 602, wherein the third through hole exposes the surface of the first metal layer 603; and a third connection structure located in the third through hole, wherein the third connection structure electrically connects the first metal layer 603 and the second metal layer 607.

[0192] In this embodiment, the third connection structure includes: a fourth conductive layer 609 located on the side wall surface of the third through hole and the surface of the first metal layer 603, and the fourth conductive layer 609 is connected to the second metal layer 607; and a third connection layer 608 embedded in the third through hole and electrically connected to the fourth conductive layer 609.

[0193] In this embodiment, the fourth conductive layer 609 is formed simultaneously with the second metal layer 607. The material of the fourth conductive layer 609 is the same as that of the second metal layer 607.

[0194] In another embodiment, the third connection structure further includes: a fifth conductive layer (not shown) located between the fourth conductive layer and the third connection layer. The fourth conductive layer is formed simultaneously with the second electrode layer and is made of the same material as the second electrode layer; the fifth conductive layer is formed simultaneously with the second metal layer and is made of the same material as the second metal layer.

[0195] The process of forming the third connection structure, the second electrode layer 605 and the second metal layer 607 is described in detail in FIG9 and FIG10 , and will not be further described here.

[0196] In this embodiment, the material of the third connection layer 608 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0197] The first electrode layer 601, the first passivation layer 602 and the first metal layer 603 on the first non-resonance region II constitute a first capacitor C1, the second electrode layer 605, the second passivation layer 606 and the second metal layer 607 on the resonance region I constitute a second capacitor C2, and the third connection structure electrically connects the first metal layer 603 and the second metal layer 607, that is, the first capacitor C1 and the second capacitor C2 are connected in parallel on the resonance region I, and the first capacitor C1 and the second capacitor C2 are connected in series, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, so that adjacent interference frequency bands are not easily passed through, thereby achieving the effect of enhanced near-end out-of-band suppression.

[0198] 17 and 18 are schematic structural diagrams of a bulk acoustic wave resonator device forming process according to another embodiment of the present invention.

[0199] Please refer to FIG17 and FIG18 , FIG17 is a top view of the second side S2 of FIG18 , and FIG18 is a schematic cross-sectional view of the structure of FIG17 along the section line AOA1 , the bulk acoustic wave resonator device includes:

[0200] Cavity 704;

[0201] A piezoelectric layer 700 includes a first side S1 and a second side S2 opposite to each other in a direction perpendicular to a surface of the piezoelectric layer 700. The cavity 704 is located on the first side S1 of the piezoelectric layer 700. The piezoelectric layer 700 includes a resonant region I and a first non-resonant region II, a second non-resonant region III, and a third non-resonant region IV adjacent to the resonant region I. The first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are separate from each other.

[0202] A first electrode layer 701, at least the first electrode layer 701 on the resonance zone I is located in the cavity 704, and the first electrode layer 701 is located on the first side S1 surface of the resonance zone I and the first side S1 surface of the first non-resonance zone II;

[0203] A first passivation layer 702 located on the first side S1 surface of the second non-resonance region III, the first side S1 surface of the third non-resonance region IV, the top surface of the first electrode layer 701 and the edge sidewall surface of the first electrode layer 701;

[0204] A second electrode layer 705, the second electrode layer 705 is located on the second side S2 surface of the piezoelectric layer 700, and the second electrode layer 705 is located on the second side S2 surface of the resonance zone I and the second side S2 surface of the second non-resonance zone III;

[0205] A second passivation layer 706 located on the second side S2 surface of the first non-resonance region II, the second side S2 surface of the third non-resonance region IV, the top surface of the second electrode layer 705, and the edge sidewall surface of the second electrode layer 705;

[0206] A first metal layer 703 located on the first side S1 and a second metal layer 707 located on the second side S2, wherein the first metal layer 703 and the second metal layer 707 are electrically connected.

[0207] The first metal layer 703 is located on the surface of the first passivation layer 702 on the first non-resonance zone II and the third non-resonance zone IV. The second metal layer 707 is located on the surface of the second passivation layer 706 on the second non-resonance zone III and the third non-resonance zone IV.

[0208] In this embodiment, the projection pattern of the resonant region I is a regular hexagon, and the first non-resonant region II, the second non-resonant region III, and the third non-resonant region IV are respectively connected to one side of the regular hexagon.

[0209] In this embodiment, the first non-resonance zone II, the second non-resonance zone III, and the third non-resonance zone IV are respectively connected to three consecutive sides of the regular hexagon, and the third non-resonance zone IV is located between the second non-resonance zone III and the first non-resonance zone II.

[0210] In this embodiment, it also includes: a third through hole (not shown) located in the third non-resonant zone IV, in the second passivation layer 706 and in the first passivation layer 702, the third through hole exposing the surface of the first metal layer 703; a third connection structure located in the third through hole, the third connection structure electrically connecting the first metal layer 703 and the second metal layer 707.

[0211] In this embodiment, the third connection structure includes: a fourth conductive layer 709 located on the side wall surface of the third through hole and the surface of the first metal layer 703, and the fourth conductive layer 709 is connected to the second metal layer 707; and a third connection layer 708 embedded in the third through hole and electrically connected to the fourth conductive layer 709.

[0212] In this embodiment, the fourth conductive layer 709 is formed simultaneously with the second metal layer 707. The material of the fourth conductive layer 709 is the same as that of the second metal layer 707.

[0213] In another embodiment, the third connection structure further includes: a fifth conductive layer (not shown) located between the fourth conductive layer and the third connection layer. The fourth conductive layer is formed simultaneously with the second electrode layer and is made of the same material as the second electrode layer; the fifth conductive layer is formed simultaneously with the second metal layer and is made of the same material as the second metal layer.

[0214] The process of forming the third connection structure, the second electrode layer 705 and the second metal layer 707 is described in detail in FIG9 and FIG10 , and will not be further described here.

[0215] In this embodiment, the material of the third connection layer 708 includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

[0216] The first electrode layer 701, the first passivation layer 702 and the first metal layer 703 on the first resonance zone II constitute a first capacitor C1, and the second electrode layer 705, the second passivation layer 706 and the second metal layer 707 on the third resonance zone IV constitute a second capacitor C2. The third connection structure electrically connects the first metal layer 703 and the second metal layer 707, that is, the first capacitor C1 and the second capacitor C2 are connected in parallel on the resonance zone I. The first capacitor C1 and the second capacitor C2 are connected in series, which can effectively reduce the electromechanical coupling coefficient of the bulk acoustic wave resonator device, reduce the bandwidth between the resonant frequency and the antiresonant frequency of the bulk acoustic wave resonator device, and increase the Q value of the parallel resonance point. The capacitor structure is connected in the bulk acoustic wave resonator circuit, so that adjacent interference frequency bands are not easily passed through, thereby achieving the effect of enhancing near-end out-of-band suppression.

[0217] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A bulk acoustic wave filter device, characterized in that: include: A piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to a surface of the piezoelectric layer, the piezoelectric layer comprising a resonant region and a first non-resonant region and a second non-resonant region adjacent to the resonant region, the first non-resonant region and the second non-resonant region being separated from each other; A first electrode layer, the first electrode layer is located on a first side surface of the resonance region and a first side surface of the first non-resonance region; A first passivation layer, wherein the first passivation layer is located on a first side surface of the second non-resonance region, a top surface of the first electrode layer, and an edge sidewall surface of the first electrode layer; A second electrode layer, the second electrode layer is located on a second side surface of the piezoelectric layer, and the second electrode layer is located on a second side surface of the resonance region and a portion of a second side surface of the second non-resonance region; A second passivation layer, wherein the second passivation layer is located on a second side surface of the first non-resonance region, a top surface of the second electrode layer, and an edge sidewall surface of the second electrode layer; a first metal layer located on the first side, or a second metal layer located on the second side, The first metal layer is located on the surface of the first passivation layer on the resonant region and the second non-resonant region, or the first metal layer is located on the surface of the first passivation layer on the first non-resonant region and the second non-resonant region, the first metal layer, the first passivation layer and the first electrode layer constitute a first capacitor, and the first metal layer is electrically connected to the second electrode layer, The second metal layer is located on the surface of the second passivation layer on the resonance zone and the first non-resonance zone, or the second metal layer is located on the surface of the second passivation layer on the first non-resonance zone and the second non-resonance zone, the second metal layer, the second passivation layer and the second electrode layer constitute a second capacitor, and the second metal layer is electrically connected to the first electrode layer.

2. The bulk acoustic wave filter device according to claim 1, characterized in that: When the first metal layer is located on the first side, it also includes: a first through hole located in the second non-resonance zone and the first passivation layer, the first through hole exposing the surface of the first metal layer; and a first connection structure located in the first through hole, the first connection structure electrically connecting the first metal layer and the second electrode layer.

3. The bulk acoustic wave filter device according to claim 2, characterized in that: The first connection structure includes: a first conductive layer located on the side wall surface of the first through hole and the surface of the first metal layer, the first conductive layer is connected to the second electrode layer; and a first connection layer embedded in the first through hole and electrically connected to the first conductive layer.

4. The bulk acoustic wave filter device according to claim 3, characterized in that: The material of the first conductive layer is the same as that of the second electrode layer.

5. The bulk acoustic wave filter device according to claim 3, characterized in that: The material of the first connecting layer includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

6. The bulk acoustic wave filter device according to claim 1, characterized in that: When the second metal layer is located on the second side, it also includes: a second through hole located in the first non-resonant region and the second passivation layer, the bottom of the second through hole exposes the surface of the first electrode layer; a second connection structure located in the second through hole, the second connection structure electrically connects the second metal layer and the first electrode layer.

7. The bulk acoustic wave filter device according to claim 6, characterized in that: The second connection structure includes: a second conductive layer located on the side wall surface of the second through hole and the surface of the first electrode layer; and a second connection layer embedded in the second through hole and electrically connected to the second conductive layer.

8. The bulk acoustic wave filter device according to claim 7, characterized in that: The second connection structure further includes: a third conductive layer located between the second conductive layer and the second connection layer.

9. The bulk acoustic wave filter device according to claim 8, characterized in that: The material of the second conductive layer is the same as that of the second electrode layer; the material of the third conductive layer is the same as that of the second metal layer.

10. The bulk acoustic wave filter device according to claim 7, characterized in that: The material of the second connecting layer includes metal or metal nitride; the metal includes: a combination of one or more of copper, aluminum, tungsten, cobalt, nickel, molybdenum, tungsten, titanium, platinum and tantalum; the metal nitride includes a combination of one or more of tantalum nitride and titanium nitride.

11. The bulk acoustic wave filter device according to claim 1, characterized in that: The projection pattern of the resonance region is a regular hexagon, and when the first non-resonance region and the second non-resonance region are respectively connected to two opposite sides of the regular hexagon, the first metal layer is located on the surface of the first passivation layer on the resonance region and the second non-resonance region, or the second metal layer is located on the surface of the second passivation layer on the first non-resonance region and the second non-resonance region; When the first non-resonance region and the second non-resonance region are respectively connected to two adjacent sides of the regular hexagon, the first metal layer is located on the first non-resonance region and on the surface of the first passivation layer on the second non-resonance region, or the second metal layer is located on the resonance region and on the surface of the second passivation layer on the first non-resonance region.

12. The bulk acoustic wave filter device according to claim 1, characterized in that: The thickness of the first passivation layer is smaller than the thickness of the piezoelectric layer; the thickness of the second passivation layer is smaller than the thickness of the piezoelectric layer.

13. A method for forming a bulk acoustic wave filter device, characterized in that: include: Providing a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to a surface of the piezoelectric layer, the piezoelectric layer comprising a resonant region and a first non-resonant region and a second non-resonant region adjacent to the resonant region, the first non-resonant region and the second non-resonant region being separated from each other; Forming a first electrode layer and a first passivation layer on a first side of the piezoelectric layer, wherein the first electrode layer is located on a first side surface of the resonant region and a first side surface of the first non-resonant region, and the first passivation layer is located on a first side surface of the second non-resonant region, a top surface of the first electrode layer, and a sidewall surface of an edge of the first electrode layer; Forming a second electrode layer and a second passivation layer on the second side of the piezoelectric layer, wherein the second electrode layer is located on the second side surface of the piezoelectric layer, the second electrode layer is located on the second side surface of the resonance region and a portion of the second side surface of the second non-resonance region, and the second passivation layer is located on the second side surface of the first non-resonance region, the top surface of the second electrode layer, and the sidewall surface of the edge of the second electrode layer; forming a first metal layer on the first side, or forming a second metal layer on the second side, The first metal layer is located on the surface of the first passivation layer on the resonant region and the second non-resonant region, or the first metal layer is located on the surface of the first passivation layer on the first non-resonant region and the second non-resonant region, the first metal layer, the first passivation layer and the first electrode layer constitute a first capacitor, and the first metal layer is electrically connected to the second electrode layer, The second metal layer is located on the surface of the second passivation layer on the resonance zone and the first non-resonance zone, or the second metal layer is located on the surface of the second passivation layer on the first non-resonance zone and the second non-resonance zone, the second metal layer, the second passivation layer and the second electrode layer constitute a second capacitor, and the second metal layer is electrically connected to the first electrode layer.

14. The method for forming a bulk acoustic wave filter device according to claim 13, wherein: When the first metal layer is located on the first side, the method of electrically connecting the first metal layer and the second electrode layer includes: forming a first through hole located in the second non-resonance zone and in the first passivation layer, the first through hole exposing the surface of the first metal layer; forming a first connection structure in the first through hole, the first connection structure electrically connecting the first metal layer and the second electrode layer.

15. The method for forming a bulk acoustic wave filter device according to claim 14, wherein: The first connection structure includes: a first conductive layer located on the surface of the side wall of the first through hole and the surface of the first metal layer, the first conductive layer is connected to the second electrode layer; a first connection layer embedded in the first through hole and electrically connected to the first conductive layer; the first conductive layer and the second electrode layer are formed synchronously.

16. The method for forming a bulk acoustic wave filter device according to claim 13, wherein: When the second metal layer is located on the second side, the method of electrically connecting the second metal layer and the first electrode layer includes: forming a second through hole located in the first non-resonance zone and the second passivation layer, the second through hole exposing the surface of the first electrode layer; forming a second connection structure in the second through hole, the second connection structure electrically connecting the second metal layer and the first electrode layer.

17. The method for forming a bulk acoustic wave filter device according to claim 16, wherein: The second connection structure includes: a second conductive layer located on the side wall surface of the second through hole and the surface of the first electrode layer; and a second connection layer embedded in the second through hole and electrically connected to the second conductive layer.

18. The method for forming a bulk acoustic wave filter device according to claim 17, wherein: The second connection structure further includes: a third conductive layer located between the second conductive layer and the second connection layer.

19. The method for forming a bulk acoustic wave filter device according to claim 18, wherein: The second conductive layer is formed synchronously with the second electrode layer; and the third conductive layer is formed synchronously with the second metal layer.

20. The method for forming a bulk acoustic wave filter device according to claim 13, wherein: The projection pattern of the resonance region is a regular hexagon, and when the first non-resonance region and the second non-resonance region are respectively connected to two opposite sides of the regular hexagon, the first metal layer is located on the surface of the first passivation layer on the resonance region and the second non-resonance region, or the second metal layer is located on the surface of the second passivation layer on the first non-resonance region and the second non-resonance region; When the first non-resonance region and the second non-resonance region are respectively connected to two adjacent sides of the regular hexagon, the first metal layer is located on the first non-resonance region and on the surface of the first passivation layer on the second non-resonance region, or the second metal layer is located on the resonance region and on the surface of the second passivation layer on the first non-resonance region.

21. A bulk acoustic wave filter device, characterized in that: include: A piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to a surface of the piezoelectric layer, the piezoelectric layer comprising a resonant region and a first non-resonant region, a second non-resonant region and a third non-resonant region adjacent to the resonant region, the first non-resonant region, the second non-resonant region and the third non-resonant region being separate from each other; A first electrode layer, the first electrode layer is located on a first side surface of the resonance region and a first side surface of the first non-resonance region; A first passivation layer is located on a first side surface of the second non-resonance region, a first side surface of the third non-resonance region, a top surface of the first electrode layer, and a sidewall surface of an edge of the first electrode layer; A second electrode layer, the second electrode layer is located on a second side surface of the piezoelectric layer, and the second electrode layer is located on a second side surface of the resonant region and a second side surface of the second non-resonant region; A second passivation layer, wherein the second passivation layer is located on the second side surface of the first non-resonance region, the second side surface of the third non-resonance region, the top surface of the second electrode layer, and the edge sidewall surface of the second electrode layer; a first metal layer located on the first side, and a second metal layer located on the second side, wherein the first metal layer is electrically connected to the second metal layer, The first metal layer is located on the surface of the first passivation layer on the first non-resonance region and the third non-resonance region, the second metal layer is located on the surface of the second passivation layer on the resonance region and the third non-resonance region, or the second metal layer is located on the surface of the second passivation layer on the second non-resonance region and the third non-resonance region; Alternatively, the first metal layer is located on a surface of the first passivation layer on the resonance region and the third non-resonance region, and the second metal layer is located on a surface of the second passivation layer on the resonance region and the third non-resonance region.

22. The bulk acoustic wave filter device according to claim 21, characterized in that: Also includes: a third through hole located in the second passivation layer, in the third non-resonant region and in the first passivation layer, wherein the third through hole exposes the surface of the first metal layer; A third connection structure is located in the third through hole, and the third connection structure electrically connects the first metal layer and the second metal layer.

23. The bulk acoustic wave filter device according to claim 22, characterized in that: The third connection structure includes: a fourth conductive layer located on the side wall surface of the third through hole and the surface of the first metal layer, the fourth conductive layer is connected to the second metal layer; and a third connection layer embedded in the third through hole and electrically connected to the fourth conductive layer.

24. The bulk acoustic wave filter device according to claim 23, characterized in that: The material of the fourth conductive layer is the same as that of the second metal layer.

25. The bulk acoustic wave filter device according to claim 21, characterized in that: The projection pattern of the resonant region is a regular hexagon, and the first non-resonant region, the second non-resonant region and the third non-resonant region are respectively connected to one side of the regular hexagon.

26. The bulk acoustic wave filter device according to claim 25, characterized in that: The second non-resonance zone and the third non-resonance zone are respectively connected to two opposite sides of the regular hexagon. When the first non-resonance zone is adjacent to the second non-resonance zone, the first metal layer is located on the surface of the first passivation layer on the resonance zone and the third non-resonance zone, and the second metal layer is located on the surface of the second passivation layer on the resonance zone and the second non-resonance zone.

27. The bulk acoustic wave filter device according to claim 25, characterized in that: The first non-resonance region, the second non-resonance region and the third non-resonance region are respectively connected to three continuous sides of the regular hexagon, and when the first non-resonance region is located between the second non-resonance region and the third non-resonance region, the first metal layer is located on the surface of the first passivation layer on the first non-resonance region and the third non-resonance region, and the second metal layer is located on the surface of the second passivation layer on the resonance region and the third non-resonance region; When the third non-resonance zone is located between the second non-resonance zone and the first non-resonance zone, the first metal layer is located on the surface of the first passivation layer on the first non-resonance zone and the third non-resonance zone, and the second metal layer is located on the surface of the second passivation layer on the second non-resonance zone and the third non-resonance zone.

28. The bulk acoustic wave filter device according to claim 21, characterized in that: The thickness of the first passivation layer is smaller than the thickness of the piezoelectric layer; the thickness of the second passivation layer is smaller than the thickness of the piezoelectric layer.

29. A method for forming a bulk acoustic wave filter device, characterized in that: include: Providing a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other in a direction perpendicular to a surface of the piezoelectric layer, the piezoelectric layer comprising a resonant region and a first non-resonant region, a second non-resonant region and a third non-resonant region adjacent to the resonant region, the first non-resonant region, the second non-resonant region and the third non-resonant region being separated from each other; Forming a first electrode layer and a first passivation layer on a first side of the piezoelectric layer, wherein the first electrode layer is located on a first side surface of the resonant region and a first side surface of the first non-resonant region, and the first passivation layer is located on a first side surface of the second non-resonant region, a top surface of the first electrode layer, and a sidewall surface of an edge of the first electrode layer; Forming a second electrode layer and a second passivation layer on the second side of the piezoelectric layer, wherein the second electrode layer is located on the second side surface of the piezoelectric layer, the second electrode layer is located on the second side surface of the resonance region and the second side surface of the second non-resonance region, and the second passivation layer is located on the second side surface of the first non-resonance region, the top surface of the second electrode layer, and the sidewall surface of the edge of the second electrode layer; forming a first metal layer located on the first side, and forming a second metal layer located on the second side, wherein the first metal layer is electrically connected to the second metal layer, The first metal layer is located on the surface of the first passivation layer on the first non-resonance region and the third non-resonance region, the second metal layer is located on the surface of the second passivation layer on the resonance region and the third non-resonance region, or the second metal layer is located on the surface of the second passivation layer on the second non-resonance region and the third non-resonance region; Alternatively, the first metal layer is located on a surface of the first passivation layer on the resonance region and the third non-resonance region, and the second metal layer is located on a surface of the second passivation layer on the resonance region and the third non-resonance region.

30. The method for forming a bulk acoustic wave filter device according to claim 29, wherein: The method for electrically connecting the first metal layer and the second metal layer includes: forming a third through hole in the second passivation layer, in the third non-resonant zone and in the first passivation layer, wherein the third through hole exposes the surface of the first metal layer; forming a third connection structure in the third through hole, wherein the third connection structure electrically connects the first metal layer and the second metal layer.

31. The method for forming a bulk acoustic wave filter device according to claim 30, wherein: The third connection structure includes: a fourth conductive layer located on the side wall surface of the third through hole and the surface of the first metal layer, the fourth conductive layer being connected to the second metal layer; a third connection layer embedded in the third through hole and electrically connected to the fourth conductive layer; the fourth conductive layer and the second metal layer are formed simultaneously.

32. The method for forming a bulk acoustic wave filter device according to claim 29, wherein: The projection pattern of the resonant region is a regular hexagon, and the first non-resonant region, the second non-resonant region and the third non-resonant region are respectively connected to one side of the regular hexagon.

33. The method for forming a bulk acoustic wave filter device according to claim 32, wherein: The second non-resonance zone and the third non-resonance zone are respectively connected to two opposite sides of the regular hexagon. When the first non-resonance zone is adjacent to the second non-resonance zone, the first metal layer is located on the surface of the first passivation layer on the resonance zone and the third non-resonance zone, and the second metal layer is located on the surface of the second passivation layer on the resonance zone and the second non-resonance zone.

34. The method for forming a bulk acoustic wave filter device according to claim 33, wherein: The first non-resonance region, the second non-resonance region and the third non-resonance region are respectively connected to three continuous sides of the regular hexagon, and when the first non-resonance region is located between the second non-resonance region and the third non-resonance region, the first metal layer is located on the surface of the first passivation layer on the first non-resonance region and the third non-resonance region, and the second metal layer is located on the surface of the second passivation layer on the resonance region and the third non-resonance region; When the third non-resonance zone is located between the second non-resonance zone and the first non-resonance zone, the first metal layer is located on the surface of the first passivation layer on the first non-resonance zone and the third non-resonance zone, and the second metal layer is located on the surface of the second passivation layer on the second non-resonance zone and the third non-resonance zone.

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