Thin film bulk acoustic wave resonator and method for manufacturing the same

Abstract

The present invention relates to a thin film bulk acoustic wave resonator and a manufacturing method thereof, wherein the thin film bulk acoustic wave resonator comprises: a first substrate provided with a first cavity; a piezoelectric laminate structure, comprising a first electrode, a piezoelectric layer and a second electrode stacked in sequence from bottom to top, the piezoelectric layer covers the first cavity, the edges of the first electrode and the second electrode are both located within the boundary of the area enclosed by the first cavity, and the effective resonance area comprises an area where the first electrode, the piezoelectric layer and the second electrode overlap each other in a direction perpendicular to the surface of the piezoelectric layer; a first electrode lead-out structure, connecting the edge of the first electrode and extending to the invalid resonance area as a first signal connection end, and enclosing a first gap with the piezoelectric laminate structure at the edge of the effective resonance area; a second electrode lead-out structure, connecting the edge of the second electrode and extending to the invalid resonance area as a second signal connection end, and enclosing a second gap with the piezoelectric laminate structure at the edge of the effective resonance area. The present invention improves the Q value by eliminating the boundary clutter of the effective resonance area.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor device manufacturing, and in particular to a thin film bulk acoustic wave resonator and a manufacturing method thereof. Background Art

[0002] Since analog RF communication technology was developed in the early 1990s, RF front-end modules have gradually become the core components of communication equipment. Among all RF front-end modules, filters have become the components with the strongest growth momentum and the greatest development prospects. With the rapid development of wireless communication technology and the increasing maturity of 5G communication protocols, the market has also put forward more stringent standards for the performance of RF filters in all aspects. The performance of the filter is determined by the resonator units that make up the filter. Among the existing filters, the film bulk acoustic resonator (FBAR) has become one of the most suitable filters for 5G applications due to its small size, low insertion loss, large out-of-band suppression, high quality factor, high operating frequency, large power capacity and good anti-static shock ability.

[0003] Generally, a film bulk acoustic wave resonator includes two film electrodes, and a piezoelectric film layer is arranged between the two film electrodes. Its working principle is to utilize the piezoelectric film layer to generate vibration under an alternating electric field. The vibration excites a bulk acoustic wave that propagates along the thickness direction of the piezoelectric film layer. The sound wave is reflected back when it reaches the interface between the upper and lower electrodes and the air, and then reflects back and forth inside the film to form an oscillation. When the sound wave propagates in the piezoelectric film layer at an odd multiple of half the wavelength, a standing wave oscillation is formed.

[0004] However, the quality factor (Q) of the currently manufactured cavity-type FBAW resonators cannot be further improved, and therefore cannot meet the requirements of high-performance radio frequency systems. Summary of the invention

[0005] The object of the present invention is to provide a thin film bulk acoustic wave resonator and a manufacturing method thereof, which can improve the quality factor of the thin film bulk acoustic wave resonator and thus improve the device performance.

[0006] In order to achieve the above object, the present invention provides a thin film bulk acoustic wave resonator, comprising:

[0007] a first substrate, wherein a first cavity is provided in the first substrate;

[0008] A piezoelectric stack structure, comprising, from bottom to top, a first electrode, a piezoelectric layer, and a second electrode stacked in sequence, wherein the edges of the first electrode and the second electrode are both located within the boundary of the area enclosed by the first cavity, and the effective resonance area includes an area where the first electrode, the piezoelectric layer, and the second electrode overlap each other in a direction perpendicular to the surface of the piezoelectric layer;

[0009] A first electrode lead-out structure, connected to the edge of the first electrode and extending to the invalid resonance region as a first signal connection end, and forming a first gap with the piezoelectric stack structure at the edge of the effective resonance region;

[0010] The second electrode lead-out structure is connected to the edge of the second electrode and extends to the invalid resonance area as a second signal connection end, and forms a second gap with the piezoelectric stack structure at the edge of the effective resonance area.

[0011] The present invention also provides a method for manufacturing a thin film bulk acoustic wave resonator, comprising:

[0012] providing a temporary substrate;

[0013] forming a second electrode layer, a piezoelectric layer and a first electrode in sequence on the temporary substrate, wherein the first electrode is located in an effective resonance region;

[0014] forming a first electrode lead-out structure, wherein the first electrode lead-out structure is connected to an edge of the first electrode and extends to an invalid resonance region as a first signal connection end, and forms a first gap with the piezoelectric layer and the first electrode at a boundary of the effective resonance region;

[0015] forming a first sacrificial layer to cover the first electrode and the first electrode lead-out structure located at the boundary of the effective resonance region;

[0016] forming the first substrate, covering the first sacrificial layer and the piezoelectric layer;

[0017] removing the temporary substrate;

[0018] The second electrode layer is patterned to form the second electrode; the effective resonance region includes a region where the first electrode, the piezoelectric layer and the second electrode overlap each other in a direction perpendicular to a surface of the piezoelectric layer;

[0019] forming a second electrode lead-out structure, wherein the second electrode lead-out structure is connected to an edge of the second electrode and extends to an invalid resonance region as a second signal connection end, and forms a second gap with the piezoelectric layer and the second electrode at an edge of the effective resonance region;

[0020] The first sacrificial layer is removed.

[0021] The beneficial effects of the thin film bulk acoustic wave resonator of the present invention are:

[0022] By adopting separate first electrode lead-out structures and second electrode lead-out structures on the first electrode side and the second electrode side respectively, the first electrode lead-out structure and the second electrode lead-out structure respectively form a first gap and a second gap in the boundary area of ​​the effective resonance zone, and the first gap and the second gap can achieve the effect of eliminating the boundary clutter of the effective resonance zone, thereby improving the Q value of the resonator.

[0023] Furthermore, the first electrode lead-out structure and the second electrode lead-out structure are made of metal materials with lower resistivity and better thermal conductivity, which can reduce impedance and enhance thermal conductivity.

[0024] Furthermore, the piezoelectric layer is provided with a gap edge gap so that the edge of the piezoelectric layer is exposed to the air, which can suppress the shear wave loss.

[0025] Furthermore, when the piezoelectric layer is a complete film layer, the structural strength of the resonator can be increased; the piezoelectric layer is formed on a flat electrode layer, which can make the piezoelectric layer have a better lattice orientation, improve the piezoelectric properties of the piezoelectric layer, and thus improve the overall performance of the resonator.

[0026] Furthermore, a first protrusion is arranged on the surface of the first electrode and / or a second protrusion is arranged on the surface of the second electrode, and an acoustic impedance mismatch zone is formed in the area where the first protrusion and the second protrusion are located, which can achieve acoustic impedance mismatch between the boundary of the effective resonance zone and the inside of the effective resonance zone; the projection of the first protrusion and the first overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap, or the projection of the second protrusion and the second overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap, which can jointly suppress lateral noise leakage and further improve the quality factor of the resonator.

[0027] Furthermore, a first dielectric layer and a second dielectric layer are formed on the upper and lower surfaces of the piezoelectric layer respectively, which can improve the bonding effect when a top cover is subsequently formed. Meanwhile, the arrangement of the first dielectric layer and the second dielectric layer can also improve the overall mechanical strength of the resonator.

[0028] The beneficial effects of the method for manufacturing a thin film bulk acoustic wave resonator of the present invention are:

[0029] The second electrode layer and the piezoelectric layer are sequentially formed on the surface of the temporary substrate, so that the piezoelectric layer can be formed on the flat second electrode layer, ensuring that the piezoelectric layer has a good lattice orientation, improving the piezoelectric characteristics of the piezoelectric layer, and thus improving the performance of the resonator. By first forming the first electrode and the first electrode lead-out structure on the first surface of the piezoelectric layer, and then forming the second electrode and the second electrode lead-out structure on the second surface, this process of electrode patterning on both sides of the piezoelectric layer avoids etching of the piezoelectric layer during the electrode formation process, ensures the integrity and flatness of the piezoelectric layer, reduces the impact on the piezoelectric layer, and thus improves the performance of the resonator; and this method is compatible with the main process of the resonator, and the process is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic cross-sectional structure diagram of a thin film bulk acoustic wave resonator according to an embodiment of the present invention is shown;

[0032] Figure 1A Shows Figure 1 Top view along the X direction;

[0033] Figure 2 A schematic cross-sectional structure diagram of a thin film bulk acoustic wave resonator including a first protrusion, a second protrusion, a first dielectric layer and a second dielectric layer according to an embodiment of the present invention is shown;

[0034] Figure 2A for Figure 2 Top view along the X direction;

[0035] Figure 3 A schematic cross-sectional structure diagram of a thin film bulk acoustic wave resonator including a top cover according to an embodiment of the present invention is shown;

[0036] Figure 4 A schematic cross-sectional structure diagram of a thin film bulk acoustic wave resonator including an air gap, a first dielectric layer, and a second dielectric layer according to another embodiment of the present invention is shown;

[0037] Figure 5 A flow chart showing a method for manufacturing a thin film bulk acoustic wave resonator in one embodiment of the present invention is shown;

[0038] Figure 6-Figure 16 A structural schematic diagram corresponding to corresponding steps of a method for manufacturing a thin film bulk acoustic wave resonator in an embodiment of the present invention is shown.

[0039] Description of reference numerals:

[0040] 1. first substrate; 11. base; 12. support layer; 121. first cavity; 3. piezoelectric stack structure; 31. first electrode; 31'. first electrode layer; 32. piezoelectric layer; 321. air gap; 33. second electrode; 33'. second electrode layer; 4. first electrode lead structure; 41. first overhead portion; 42. first overlapping portion; 43. first gap; 5. second electrode lead structure; 51. second overhead portion; 52. second overlapping portion; 53. second gap; 6. first protrusion; 7. second protrusion; 8. top cover; 81. bonding layer; 811. second cavity; 812. release hole; 82. second substrate; 90. temporary substrate; 91. first sacrificial layer; 92. first sacrificial protrusion; 93. second sacrificial protrusion; 94. second sacrificial layer; 95. first dielectric layer; 96. second dielectric layer; 97. isolation layer. DETAILED DESCRIPTION

[0041] The currently manufactured cavity-type thin film bulk acoustic wave resonators have problems such as shear wave loss, insufficient structural strength, which makes it impossible to further improve the quality factor (Q), and low yield rate. Therefore, they cannot meet the needs of high-performance RF systems.

[0042] In order to solve the above problems, the present invention provides a thin film bulk acoustic wave resonator, by respectively adopting a separate first electrode lead-out structure and a second electrode lead-out structure on the first electrode side and the second electrode side, the first electrode lead-out structure and the second electrode lead-out structure are respectively located on both sides of the effective resonance region to form an obliquely symmetrical structure, the first electrode lead-out structure and the second electrode lead-out structure respectively form a first gap and a second gap in the boundary area of ​​the effective resonance region, the first gap and the second gap can achieve the effect of eliminating the boundary clutter of the effective resonance region, thereby improving the Q value of the resonator.

[0043] The following is a further detailed description of the thin film bulk acoustic resonator and the method for making the same in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description and drawings. However, it should be noted that the concept of the technical solution of the present invention can be implemented in a variety of different forms and is not limited to the specific embodiments described herein. The drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0044] The terms "first", "second", etc. in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms used in this way are interchangeable, for example, so that the embodiments of the invention described herein can be operated in an order other than that described or shown herein. Similarly, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method. If the components in a certain figure are the same as the components in other figures, although these components can be easily identified in all figures, in order to make the description of the figures clearer, this specification will not mark all the same component numbers in each figure.

[0045] Figure 1 A schematic diagram of a cross-sectional structure of a thin film bulk acoustic wave resonator provided by an embodiment of the present invention is shown in FIG. Figure 1 , the thin film bulk acoustic wave resonator comprises:

[0046] A first substrate 1, wherein a first cavity 121 is provided in the first substrate 1;

[0047] The piezoelectric stack structure 3 includes, from bottom to top, a first electrode 31, a piezoelectric layer 32, and a second electrode 33 stacked in sequence, wherein the edges of the first electrode 31 and the second electrode 33 are both located within the boundary of the area enclosed by the first cavity 121, the effective resonance region includes the region where the first electrode 31, the piezoelectric layer 32, and the second electrode 33 overlap each other in a direction perpendicular to the surface of the piezoelectric layer 32, and the invalid resonance region is the region outside the effective resonance region;

[0048] The first electrode lead-out structure 4 is connected to the edge of the first electrode 31 and extends to the invalid resonance region as a first signal connection end, and forms a first gap 43 with the piezoelectric stack structure 3 at the edge of the effective resonance region;

[0049] The second electrode lead-out structure 5 is connected to the edge of the second electrode 33 and extends to the ineffective resonance region as a second signal connection end, and forms a second gap 53 with the piezoelectric stack structure 3 at the edge of the effective resonance region.

[0050] In this embodiment, the material of the first substrate 1 can be any suitable base material known to those skilled in the art, for example, it can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (SiC), carbon germanium silicon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors.

[0051] In this embodiment, the first substrate 1 is a double-layer structure, including a base 11 and a support layer 12, the support layer 12 and the piezoelectric stacked structure 3 are sequentially stacked on the base 11, and the first cavity 121 is arranged in the support layer 12. It should be noted that the support layer 12 can be combined with the base 11 by a bonding layer or deposition. The material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbon nitride or ethyl silicate. In addition, the bonding layer can also use adhesives such as photocurable materials or thermosetting materials, such as die attach film (DAF) or dry film (Dry Film). The deposition method can be chemical vapor deposition or physical vapor deposition. The material of the base 11 can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (SiC), carbon germanium silicon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors. The material of the support layer 12 can be any suitable dielectric material, including but not limited to one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc., but the technology of the present invention is not limited thereto. In other embodiments, the first substrate 1 can also be a single-layer structure, and the material is similar to the base 11.

[0052] In this embodiment, the cross-sectional shape of the first cavity 121 may be a rectangle. However, in other embodiments of the present invention, the cross-sectional shape of the first cavity 121 may also be a circle, an ellipse, or a polygon other than a rectangle, such as a pentagon, a hexagon, etc.

[0053] A piezoelectric stacked structure 3 is disposed above the first cavity 121 . The piezoelectric layer 32 covers the first cavity 121 . The edges of the first electrode 31 and the second electrode 33 are both located within the boundary of the area enclosed by the first cavity 121 .

[0054] The shapes of the second electrode 33 and the first electrode 31 may be the same or different. In the present embodiment, the second electrode 33 and the first electrode 31 have the same shape, both of which are polygons whose arbitrary two sides are not parallel. The second electrode 33 and the first electrode 31 completely overlap in the direction perpendicular to the piezoelectric layer 32. The edges of the first electrode 31 and the second electrode 33 define the boundary of the effective resonance region, that is, the edges of the first electrode 31 and the second electrode 33 are the boundaries of the effective resonance region, and the first electrode 31 and the second electrode 33 only exist above the first cavity 121. The first electrode 31 and the second electrode 33 do not overlap each other in the invalid resonance region along the direction perpendicular to the surface of the piezoelectric layer, which can avoid the high-frequency coupling problem caused by the existence of potential floating, which is beneficial to improve the Q value of the resonator.

[0055] Generally, the second electrode 33 and the first electrode 31 can use any suitable conductive material or semiconductor material known in the art, wherein the conductive material can be a metal material with conductive properties, for example, made of one of metals such as molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), or a stack of the above metals, and the semiconductor material is, for example, Si, Ge, SiGe, SiC, SiGeC, etc. The second electrode 33 and the first electrode 31 can be formed by physical vapor deposition or chemical vapor deposition methods such as magnetron sputtering and evaporation.

[0056] The material of the piezoelectric layer 32 can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3) and a combination thereof. When the piezoelectric layer 32 includes aluminum nitride (AlN), the piezoelectric layer 32 may also include a rare earth metal, such as scandium (Sc), erbium (Er), yttrium (Y) and lanthanum (La). In addition, when the piezoelectric layer 32 includes aluminum nitride (AlN), the piezoelectric layer 32 may also include a transition metal, such as zirconium (Zr), titanium (Ti), manganese (Mn) and hafnium (Hf). The piezoelectric layer 32 can be formed by deposition using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition. In this embodiment, the second electrode 33 and the first electrode 31 are made of metal molybdenum (Mo), and the piezoelectric layer 32 is made of aluminum nitride (AlN).

[0057] In order to facilitate the subsequent input / output of electrical signals, a first electrode lead-out structure 4 and a second electrode lead-out structure 5 are also included. The first electrode lead-out structure 4 is used to connect the edge of the first electrode 31 and extend to the invalid resonance area as a first signal connection end, and the edge of the first electrode 31 and the piezoelectric layer 32 form a first gap 43. The second electrode lead-out structure 5 is used to connect the edge of the second electrode 33 and extend to the invalid resonance area as a second signal connection end, and the edge of the second electrode 33 and the piezoelectric layer 32 form a second gap 53. It should be noted that the first signal connection end can be used as a signal input end to introduce an electrical signal into the first electrode 31 in the effective resonance area, and can also be used as a signal output end to output the electrical signal on the first electrode 31. Similarly, the second signal connection end can also be used as a signal input end or a signal output end. When the first signal connection end is used as a signal input end, the second signal connection end is used as a signal output end, and vice versa. When the first signal connection end and the second signal connection end are connected to alternating current, the first signal connection end and the second signal connection end are used as a signal input end and a signal output end respectively and are in a dynamic change process.

[0058] In this embodiment, the height of the first gap 43 is greater than the thickness of the first electrode 31, so that the entire edge of the first electrode 31 is exposed to the air. Similarly, the height of the second gap 53 is also greater than the thickness of the second electrode 33, so that the entire edge of the second electrode 33 is exposed to the air. In other embodiments, the height of the first gap 43 may be equal to or less than the thickness of the first electrode 31; the height of the second gap 53 may also be equal to or less than the thickness of the second electrode 33. When the edge of the first electrode 31 is completely exposed to the air, and when the edge of the second electrode 33 is completely exposed to the air, the effect is best. The edges of the first electrode 31 and the second electrode 33 form a reflection interface with the air, so that the acoustic impedance is mismatched, the shear wave leakage is suppressed, and the effect of eliminating the boundary clutter of the effective resonance area is achieved, thereby improving the quality factor (Q value) of the resonator. In addition, the energy coupled to the first electrode 31 and the second electrode 33 is also reduced, thereby avoiding the loss of the first electrode 31 and / or the second electrode 33 to affect the quality factor (Q value) of the resonator, thereby improving the quality factor (Q value) of the resonator in the entire working frequency band. In this embodiment, the projections of the first gap 43 and the second gap 53 are located inside the first cavity 121. In other embodiments, the projections of the first gap 43 and the second gap 53 may also be located outside the first cavity 121.

[0059] In this embodiment, the first gap 43 and / or the second gap 53 are air gaps. In other embodiments, the first gap 43 and / or the second gap 53 may be vacuum gaps or other gas medium gaps. In this embodiment, the projections of the first gap 43 and the second gap 53 on the piezoelectric layer 32 form a closed ring or a ring with a gap.

[0060] The first electrode lead-out structure 4 includes: a first overhead portion 41 that encloses a first gap 43, a first lap portion 42 that connects the first overhead portion 41 and extends to the invalid resonance region, and the first lap portion 42 serves as a first signal connection end. Specifically, the first electrode lead-out structure 4 includes a first overhead portion 41 and a first lap portion 42, the first overhead portion 41 and the piezoelectric stack structure 3 enclose a first gap 43, the first lap portion 42 connects the first overhead portion 41 and extends to the invalid resonance region, and the first lap portion 41 is connected for connecting a first external signal.

[0061] In this embodiment, reference Figure 1 , the piezoelectric layer 32 covers the first cavity 121, the surface of the first overlap portion 42 facing the piezoelectric layer 32 is flush with the surface of the first electrode 31 facing the piezoelectric layer 32; and / or, the surface of the second overlap portion 52 facing the piezoelectric layer 32 is flush with the surface of the second electrode 52 facing the piezoelectric layer 32. The surfaces of the first overlap portion 42 and the second overlap portion 52 facing the piezoelectric layer 32 are flush with the surface of the piezoelectric layer 32, which can ensure the flatness of the entire piezoelectric stacked structure and the performance of the resonator.

[0062] In this embodiment, the first overlapping portion 42 surrounds the outer circumference of the first electrode 31. In another embodiment, the first overlapping portion 42 is disposed on a portion of the outer circumference of the first electrode 31, such as disposed on one side of the first electrode.

[0063] In this embodiment, the first overhead portion 41 surrounds the outer periphery of the first electrode 31. In other embodiments, the first overhead portion 41 may also be connected to one or more edges of the first electrode 31. In this case, the number of first overhead portions 41 connecting the first electrode 31 and one first overlapping portion 42 may also be multiple.

[0064] refer to Figure 1A , Figure 1A for Figure 1 Top view along the X direction. Figure 1A The first overlapping portion 42 and the first overhead portion 41 are both arranged on one side of the first electrode 31 .

[0065] refer to Figure 1AThe projection of the first overhead portion 41 on the piezoelectric layer 32 is in the shape of a strip or a surface. When it is in the shape of a surface, it can be continuously or discontinuously distributed on one or more edges of the first electrode 31; similarly, the projection of the first overlapping portion 42 on the piezoelectric layer 32 can also be in the shape of a strip or a surface; correspondingly, the combination of the first overhead portion 41 and the first overlapping portion 42 can also be multiple, for example, the first overhead portion 41 and the first overlapping portion 42 are both in the shape of a strip or both are in the shape of a surface, or one of them is a strip-shaped structure and the other is a surface-shaped structure. Furthermore, the first overhead portion 41 and the first overlapping portion 42 are both in the shape of a surface, so as to increase the contact area between the first electrode 31 and the first electrode lead-out structure 4, which is beneficial to reducing the impedance and improving the Q value of the resonator.

[0066] Continue to refer Figure 1 The second electrode lead-out structure 5 includes: a second overhead portion 51 surrounding a second gap 53, a second overlapping portion 52 connecting the second overhead portion 51 and extending to the invalid resonance region, and the second overlapping portion 52 serves as a second signal connection end.

[0067] Specifically, the second electrode lead structure 5 includes a raised second overhead portion 41 and a second overlap portion 52 . The second overhead portion 51 and the piezoelectric stacked structure 3 form a second gap 53 . The second overlap portion 52 connects the second overhead portion 51 and extends to the ineffective resonance region.

[0068] In this embodiment, the second overlapping portion 52 surrounds the outer circumference of the second electrode 33. In other embodiments, the second overlapping portion 52 is disposed on a portion of the outer circumference of the second electrode 33.

[0069] In this embodiment, the second overhead portion 51 surrounds the outer periphery of the second electrode 33. In other embodiments, the second overhead portion 51 is connected to one or more edges of the second electrode 33. In this case, the number of the second overhead portions 51 connecting the second electrode 33 and one second overlapping portion 52 can also be multiple.

[0070] refer to Figure 1A The second overhead portion 51 is connected to two sides of the second electrode 33, and the second overlap portion 52 is led out from one side. The structure of the second overhead portion 51 and the second overlap portion 52 and the positional relationship with the second electrode refer to the structure of the first overhead portion 41 and the first overlap portion 42 and the positional relationship with the first electrode 31. No further description is given here.

[0071] In this embodiment, the projections of the first electrode lead-out structure 4 and the second electrode lead-out structure 5 on the surface of the piezoelectric layer 32 are staggered to avoid high-frequency coupling caused by potential floating and prevent parasitic capacitance effect. Specifically, the projections of the second overlap portion 52 and the first overlap portion 42 on the surface of the piezoelectric layer 32 are staggered, and the projections of the first overhead portion 41 and the second overhead portion 51 on the surface of the piezoelectric layer 32 are staggered. At this time, the clutter elimination effect is best.

[0072] The material of the first electrode lead-out structure 4 and the first electrode 31 and / or the material of the second electrode lead-out structure 5 and the second electrode 33 can be the same or different. The first electrode lead-out structure 4 and / or the second electrode lead-out structure 5 adopts a metal material with low impedance to ensure a good electrical connection effect. The metal material includes one or more of gold, silver, tungsten, platinum, aluminum, and copper.

[0073] In another embodiment, reference Figure 2 The thin film bulk acoustic wave resonator further includes: a first protrusion 6 and a second protrusion 7, wherein the first protrusion 6 is located on the first electrode 31 and is distributed along the edge of the effective resonance region, and the projection of the first protrusion 6 and the first gap 43 on the surface of the piezoelectric layer 32 forms a closed ring or a ring with a gap; the second protrusion 7 is located on the second electrode 33 and is distributed along the edge of the effective resonance region, and the projection of the second protrusion 7 and the second gap 53 on the surface of the piezoelectric layer 32 forms a closed ring or a ring with a gap. Specifically, the first protrusion 6 is a continuous whole or includes a plurality of first sub-protrusions disposed intermittently, and the second protrusion 7 is a continuous whole or includes a plurality of second sub-protrusions disposed intermittently.

[0074] refer to Figure 2A , when the first protrusion 6 is a continuous whole, the projection of the first protrusion 6 on the piezoelectric layer 32 is a continuous figure, and when the second protrusion 7 is a continuous whole, the projection of the second protrusion 7 on the piezoelectric layer 32 is a continuous figure. It should be understood that when the projections of the first protrusion 6 and the second protrusion 7 on the piezoelectric layer 32 are continuous figures, it is more conducive to preventing the lateral leakage of sound waves. When the first protrusion 6 includes a plurality of first sub-protrusions arranged intermittently; and / or, the second protrusion 7 includes a plurality of second sub-protrusions arranged intermittently, the projection of the first protrusion 6 on the piezoelectric layer 32 is a discontinuous figure; and / or, the projection of the second protrusion 7 on the piezoelectric layer 32 is a discontinuous figure. When the first protrusion 6 includes a plurality of first sub-protrusions, and the second protrusion 7 includes a plurality of second sub-protrusions, the projections of the first protrusion 6 and the second protrusion 7 on the plane where the piezoelectric layer 32 is located may overlap, and their projections form a ring with a gap. In other embodiments, the projections of the first protrusion 6 and the second protrusion 7 on the plane where the piezoelectric layer 32 is located may not overlap.

[0075] In this embodiment, the projections of the first protrusion 6 and the first gap 43 on the surface of the piezoelectric layer 32 form a closed ring or a ring with a gap, and the projections of the second protrusion 7 and the second gap 53 on the surface of the piezoelectric layer 32 form a closed ring or a ring with a gap, so that the area where the first protrusion 6 and the first gap 43, the second protrusion 7 and the second gap 53 are located forms an acoustic impedance mismatch with the effective resonance area, so that the lateral sound waves propagating outward can be reflected back into the effective resonance area to suppress the leakage of lateral clutter, reduce energy loss, and improve the quality factor (Q value) of the resonator. When the projections of the first protrusion 6 and the first overhead portion 41 on the surface of the piezoelectric layer 32 are a closed ring, and the projections of the second protrusion 7 and the second overhead portion 51 on the surface of the piezoelectric layer 32 are a closed ring, it is more conducive to preventing lateral leakage of sound waves. The material of the first protrusion 6 and the second protrusion 7 may be a dielectric material or a conductive material. When the material of the first protrusion 6 and / or the second protrusion 7 is a dielectric material, it may be any one of silicon oxide, silicon nitride, silicon oxynitride or silicon carbonitride, but is not limited to the above materials. When the material of the first protrusion 6 and / or the second protrusion 7 is a conductive material, the material of the first protrusion 6 is the same as the material of the first electrode 31; and / or, the material of the second protrusion 7 is the same as the material of the second electrode 33.

[0076] Continue to refer Figure 2 and Figure 2AIn another embodiment, the thin film bulk acoustic wave resonator further includes: a first dielectric layer 95 and a second dielectric layer 96, the first dielectric layer 95 is located between the first substrate 1 and the piezoelectric layer 32, the first dielectric layer 95 is located in the invalid resonance region and is separated from the first electrode 31, the first dielectric layer 95 and the first overlap portion 42 surround the first electrode 31; the second dielectric layer 96 is located above the piezoelectric layer 32, the second dielectric layer 96 and the second overlap portion 52 surround the second electrode 33, and the second dielectric layer 96 and the second overlap portion 52 surround the second electrode 33. The first dielectric layer 95 and the second dielectric layer 96 can improve the bonding effect when the top cover is subsequently bonded; at the same time, the arrangement of the first dielectric layer 95 and the second dielectric layer 96 can also improve the overall mechanical strength of the resonator. It is worth noting that when the upper surface of the first dielectric layer 95 is flush with the upper surface of the first overlap portion 42, and the upper surface of the second dielectric layer 96 is flush with the upper surface of the second overlap portion 52, the overall mechanical strength performance is optimal. In addition, the first dielectric layer 95 can be continuously connected to the first overlap portion 42, that is, the first dielectric layer 95 and the first overlap portion 42 are connected on the surface of the piezoelectric layer 32, and form a ring on the surface of the piezoelectric layer 32, and cover the area outside the edge of the effective resonance area; the second dielectric layer 96 can be continuously connected to the second overlap portion 52, that is, the second dielectric layer 96 and the second overlap portion 52 are connected on the surface of the piezoelectric layer 32, and form a ring on the surface of the piezoelectric layer 32, and cover the area outside the edge of the effective resonance area. When the first dielectric layer 95 and the first overlap portion 42 are continuously connected, and the second dielectric layer 96 and the second overlap portion 52 are continuously connected, it is more conducive to ensuring the flatness of the piezoelectric stack structure 3 to improve the strength of the resonator. The first dielectric layer 95 can be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride and the like. The material of the second dielectric layer 96 can be selected according to the material of the first dielectric layer 95, which will not be repeated here. In this embodiment, the material of the second dielectric layer 96 can be the same as that of the first dielectric layer 95 .

[0077] It should be understood that the protrusion structure and the dielectric layer structure are independent of each other. In other embodiments, only the protrusion structure or only the dielectric layer structure may be included. When the first protrusion 6, the second protrusion 7, the first dielectric layer 95 and the second dielectric layer 96 are included at the same time, it is more conducive to suppressing shear wave leakage, balancing temperature drift, improving mechanical strength and improving the bonding effect of the top cover.

[0078] In another embodiment, reference Figure 3 In order to prevent the layers exposed in the upper space from being contaminated by the external environment, a top cover 8 is provided above the piezoelectric stack structure. The top cover 8 has a second cavity 811. The second cavity 811 is located above the first cavity 121, and the edge of the second electrode 33 is located in the second cavity 811.

[0079] Specifically, the top cover 8 can be an integral structure, and the second cavity 811 does not penetrate the top cover 8; or, the top cover includes a bonding layer 81 and a second substrate 82, the second cavity 811 is formed on the bonding layer 81, the second cavity 811 may penetrate or not penetrate the bonding layer 81, and the second substrate 82 is bonded to the top of the bonding layer 81. The bonding layer 81 can be made of silicon oxide, silicon nitride, silicon oxynitride, ethyl silicate, etc., or can be an adhesive such as a photocurable material or a thermosetting material, such as a die film (DF) or a dry film. The material of the bonding layer 81 and the material of the second substrate 82 can be the same, and the two are an integral structure, that is, the top cover 8 is an integral structure, and the second cavity 811 is formed by forming a space in the top cover 8.

[0080] In this embodiment, reference Figure 4 The piezoelectric layer 32 is also provided with an air gap 321 that penetrates the piezoelectric layer 32 and connects to the first cavity 121. The air gap 321 serves as a release hole for releasing the sacrificial material filled in the first cavity. On the other hand, the edge of the piezoelectric layer 32 can be exposed to the air, thereby effectively suppressing the shear wave. Specifically, the projections of the air gap 321, the first overhead portion, and the second overhead portion on the piezoelectric layer 32 are staggered and enclose a closed ring or a ring with a gap.

[0081] Specifically, the air gap 321 may be one or more through holes distributed above the first cavity 121 and on the periphery of the piezoelectric layer outside the effective resonance region, or the air gap 321 may be an open annular structure having a certain length. The air gap 321 connects the first cavity 121 and the second cavity 811.

[0082] In other embodiments, the piezoelectric layer 32 may also be a complete film layer. Maintaining the integrity of the film layer of the piezoelectric layer 32 can improve the structural strength of the piezoelectric layer 32, thereby improving the yield rate of the resonator.

[0083] Figure 5 FIG. 1 is a flowchart showing a method for manufacturing a thin film bulk acoustic wave resonator according to an embodiment of the present invention. Figure 5 , a method for manufacturing a thin film bulk acoustic wave resonator comprises:

[0084] S01: providing a temporary substrate;

[0085] S02: forming a second electrode layer, a piezoelectric layer and a first electrode in sequence on a temporary substrate, wherein the first electrode is located in an effective resonance region;

[0086] S03: forming a first electrode lead-out structure, wherein the first electrode lead-out structure is connected to an edge of the first electrode and extends to the invalid resonance region as a first signal connection end, and forms a first gap with the piezoelectric layer and the first electrode at an edge of the effective resonance region;

[0087] S04: forming a first sacrificial layer to cover the first electrode and the first electrode lead-out structure located at the boundary of the effective resonance region;

[0088] S05: forming a first substrate, covering the first sacrificial layer and the piezoelectric layer;

[0089] S06: removing the temporary substrate;

[0090] S07: Patterning the second electrode layer to form a second electrode, wherein the first electrode, the piezoelectric layer and the second electrode constitute a piezoelectric stack structure; an area where the first electrode, the piezoelectric layer and the second electrode overlap each other in a direction perpendicular to a surface of the piezoelectric layer constitutes an effective resonance area of ​​the resonator;

[0091] S08: forming a second electrode lead-out structure, wherein the second electrode lead-out structure is connected to an edge of the second electrode and extends to the invalid resonance region as a second signal connection end, and forms a second gap with the piezoelectric layer and the second electrode at an edge of the effective resonance region;

[0092] S09: removing the first sacrificial layer.

[0093] Figures 6 to 14 FIG. 1 is a schematic diagram of a structure corresponding to the corresponding steps of a method for manufacturing a thin film bulk acoustic wave resonator of this embodiment, and the following will refer to FIG. Figures 6 to 14 The method for manufacturing the thin film bulk acoustic wave resonator provided in this embodiment is described in detail.

[0094] refer to Figure 6 As shown, step S01 is performed to provide a temporary substrate 90 .

[0095] The material of the temporary substrate 90 may refer to the material of the first substrate 1 mentioned above, and will not be described in detail here.

[0096] In addition, in order to facilitate the subsequent peeling of the temporary substrate 90, an isolation layer 97 can also be formed on the temporary substrate 90. In the subsequent peeling process, the temporary substrate 90 can be separated from the second electrode layer formed subsequently by etching the isolation layer, which helps to quickly peel off the temporary substrate 90 and improve the process efficiency. If the isolation layer 97 is not formed between the temporary substrate 90 and the second electrode layer formed in the subsequent process, the temporary substrate 90 can be removed by mechanical grinding or the like. The material of the isolation layer 97 includes but is not limited to at least one of silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3) and aluminum nitride (AlN). The isolation layer 97 can be formed by chemical vapor deposition, magnetron sputtering or evaporation. In the present embodiment, the temporary substrate 90 is single crystal silicon, and the material of the isolation layer 97 is silicon dioxide (SiO2).

[0097] Continue to refer Figure 6, step S02 is performed to sequentially form a second electrode layer 33', a piezoelectric layer 32 and a first electrode 31 on the temporary substrate 90, wherein the first electrode 31 is located in the effective resonance region. The piezoelectric layer 32 is located between the first electrode 31 and the second electrode layer 33', and the first electrode 31 and the second electrode layer 33' are arranged opposite to each other. It should be noted that when the isolation layer 97 is formed on the temporary substrate 90, the second electrode layer 33' is formed on the isolation layer 97.

[0098] First, the second electrode layer 33' is deposited on the temporary substrate 90, and then the piezoelectric layer 32 is deposited on the second electrode layer 33', and finally the first electrode layer 31' is deposited on the piezoelectric layer 32. Through the deposition process, the second electrode layer 33' and the piezoelectric layer 32 are sequentially formed on the surface of the temporary substrate 90, so that the piezoelectric layer 32 is formed on the flat second electrode layer 33', thereby ensuring that the piezoelectric layer 32 has a good lattice orientation, improving the piezoelectric characteristics of the piezoelectric layer 32, and then improving the overall performance of the resonator.

[0099] The first electrode layer 31' is used to subsequently form the first electrode 31, and the second electrode layer 33' is used to subsequently form the second electrode 33. The materials of the first electrode layer 31', the second electrode layer 33' and the piezoelectric layer can refer to the materials of the first electrode 31, the second electrode 33 and the piezoelectric layer 32 in the structural embodiment section above. The first electrode layer 31' or the second electrode layer 33' can be formed by physical vapor deposition such as magnetron sputtering and evaporation or chemical vapor deposition. The piezoelectric layer 32 can be deposited by any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition.

[0100] After forming the first electrode layer 31', the first electrode layer 31' is patterned to form the first electrode 31. The method of patterning the first electrode layer 31' can be to etch the first electrode layer 31' using an etching process. The etching process can be a wet etching process or a dry etching process. Preferably, a dry etching process is used. The dry etching process includes but is not limited to reactive ion etching (RIE), ion beam etching, plasma etching or laser cutting. In this embodiment, the boundary of the first electrode 31 only exists within the boundary of the effective resonance region.

[0101] In other embodiments, after forming the piezoelectric layer 32, a mask layer may be formed on the piezoelectric layer 32, the mask layer exposing a portion of the surface of the piezoelectric layer 32, and a first electrode layer 31' may be deposited on the piezoelectric layer 32 and the mask layer; the mask layer and the first electrode layer 31' on the mask layer may be removed to form the first electrode. By forming the mask layer on the piezoelectric layer 32, it is possible to ensure that the piezoelectric layer 32 is not etched when the first electrode 31 is formed by patterning, thereby ensuring the integrity of the piezoelectric layer 32 and further improving the structural stability of the resonator.

[0102] Before forming the second electrode layer 33', a seed layer may be formed on the temporary substrate 90 or the isolation layer 97, so that the second electrode layer 33' is formed on the seed layer. The seed layer has a guiding property for the crystal orientation of the second electrode layer 33', the piezoelectric layer 32 and the first electrode layer 31' to be formed subsequently, so that the second electrode layer 33', the piezoelectric layer 32 and the first electrode layer 31' are convenient to grow along a specific crystal orientation, thereby ensuring the uniformity of the piezoelectric layer 32. The material of the seed layer may be aluminum nitride (AlN). In addition to AlN, the seed layer may also be formed using a metal or dielectric material having a hexagonal close-packed (HCP) structure. For example, the seed layer may also be formed of metal titanium (Ti).

[0103] Continue to refer Figure 7 , step S03 is executed to form a first electrode lead-out structure 4, the first electrode lead-out structure 4 is connected to the edge of the first electrode 31 and extends to the invalid resonance region as a first signal connection end, and forms a first gap with the piezoelectric layer 32 and the first electrode 31 at the edge of the effective resonance region. In this embodiment, the effective resonance region includes the region where the first electrode 31, the piezoelectric layer 32, and the second electrode overlap each other in a direction perpendicular to the surface of the piezoelectric layer 32, the invalid resonance region is the region outside the effective resonance region, and the edge of the effective resonance region is defined by the edge of the first electrode 31 and the second electrode.

[0104] In this embodiment, the first electrode lead-out structure 4 includes a first overhead portion 41 and a first overlap portion 42. The first overhead portion 41, the piezoelectric layer 32 and the first electrode 31 form a first gap. The first overlap portion 42 connects the first overhead portion 41 and extends to the invalid resonance region. The first overlap portion 42 is used to connect a first external signal. It should be noted that the first external signal can be an input signal or an output signal.

[0105] The method of forming the first electrode lead-out structure 4 includes:

[0106] A first sacrificial protrusion 92 is formed at the edge of the first electrode 31 , and the first sacrificial protrusion 92 is located on the first electrode 31 and the side wall of the first electrode 31 , or the first sacrificial protrusion 92 is located on the side wall of the first electrode 31 ;

[0107] forming a first conductive layer covering the piezoelectric layer 32 and the first sacrificial protrusion 92;

[0108] The first conductive layer is patterned to form a first electrode lead-out structure 4 .

[0109] Specifically, refer to Figure 7First, a first sacrificial protrusion material layer is formed on the piezoelectric layer 32, the first sacrificial protrusion material layer covers the first electrode 31 and the piezoelectric layer 32, and the first sacrificial protrusion material layer is patterned to form a first sacrificial protrusion 92 outside the edge of the first electrode 31 and close to the side wall of the first electrode 31, or the first sacrificial protrusion 92 can also be located on the first electrode 31 and extend to the piezoelectric layer 32. In this embodiment, the top of the first sacrificial protrusion 92 is higher than the surface of the first electrode 31. It should be understood that the top of the first sacrificial protrusion 92 may not be higher than the surface of the first electrode 31. However, when the top of the first sacrificial protrusion 92 is higher than the surface of the first electrode 31, when the first gap is formed after the first sacrificial protrusion 92 is removed later, the edge of the first electrode 31 can be completely exposed in the first gap, which can better suppress the loss of shear waves. The first sacrificial protrusion 92 can be a step-shaped protrusion structure or a columnar structure, and the shape of the first sacrificial protrusion 92 is not limited thereto. In the present embodiment, the material of the first sacrificial protrusion material layer includes phosphosilicate glass, low temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist.

[0110] When forming the first electrode lead-out structure 4 , a first sacrificial protrusion 92 is formed so that the first electrode lead-out structure 4 , the piezoelectric layer 32 and the first electrode 31 form a first gap to expose the edge of the first electrode 31 , thereby effectively suppressing transverse waves and improving the Q value of the resonator.

[0111] Continue to refer Figure 7 , forming a first conductive layer, covering the piezoelectric layer 32, the first electrode 31 and the first sacrificial protrusion 92; patterning the first conductive layer, forming a first electrode lead-out structure 4. In this embodiment, the first electrode lead-out structure 4 includes a first overhead portion 41 covering the first sacrificial protrusion 92 and a first lap portion 42 located on the surface of the piezoelectric layer 32, the first lap portion 42 is electrically connected to an external signal, and the first overhead portion and the first lap portion are electrically connected. The material of the first electrode lead-out structure 4 refers to the above-mentioned structural embodiment.

[0112] In this embodiment, the first overhead portion 41 is wound around the outer circumference of the first electrode 31 to form a closed ring. In another embodiment, the first overhead portion 41 is connected to one or more edges of the first electrode 31. The projection of the first overhead portion on the piezoelectric layer can be strip-shaped or planar-shaped. When it is planar, it can be continuously or discontinuously distributed on one or more edges of the second electrode; similarly, the projection of the first overlapping portion on the piezoelectric layer can also be strip-shaped or planar-shaped; correspondingly, the combination of the first overhead portion and the first overlapping portion can also be multiple, for example, the first overhead portion and the first overlapping portion are both strip-shaped or both planar-shaped, or one of them is a strip-shaped structure and the other is a planar structure. Specifically, when the first overhead portion and the first overlapping portion are both planar, the contact area between the first electrode and the first electrode lead-out structure can be increased, which is beneficial to reducing impedance and improving the Q value of the resonator.

[0113] refer to Figure 8 , perform step S04 to form a first sacrificial layer 91, covering the first electrode 31 and the first electrode lead-out structure 4 located at the boundary of the effective resonance region. In this embodiment, the first sacrificial layer 91 covers the area above the first overhead portion 41. In other embodiments, the first sacrificial layer 91 may cover part of the first overhead portion 41, or may not cover the first overhead portion 41. The material of the first sacrificial layer 91 includes any one of phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist. The method for forming the first sacrificial layer 91 may be different depending on the material, and the formation process of the first sacrificial layer 91 includes a deposition process or a spin coating process. The first cavity is formed by adopting the first sacrificial layer 91, so as to support it in the process of forming the first substrate 91, avoid uneven force on the piezoelectric stack structure 3 so as to be compressed and deformed, and support the piezoelectric layer in the subsequent reverse process, thereby ensuring the flatness of the piezoelectric stack structure 3.

[0114] refer to Fig. 9 As shown, step S05 is performed to form a first substrate 1, covering the first sacrificial layer 91 and the piezoelectric layer 32. In this embodiment, the first substrate 1 includes a base 11 and a support layer 12. The method for forming the first substrate 1 includes: forming a support layer 12, the support layer 12 covers the first sacrificial layer 91 and the piezoelectric layer 32 and the first electrode lead-out structure 4, and the method for forming the support layer 12 can adopt a deposition process. Provide a base 11, bonded to the support layer 12. The bonding method of the support layer 12 and the base 11 can refer to the relevant description in the previous structural embodiment. The materials of the support layer 12 and the base 11 can also refer to the relevant description in the previous structural embodiment.

[0115] In other embodiments, the first substrate 1 may be an integral structure, and the first substrate 1 covers the first sacrificial layer 91 and the piezoelectric layer 32. The first substrate 1 may be formed by chemical vapor deposition or physical vapor deposition, and the material of the first substrate 1 may refer to the material of the temporary substrate 90, which will not be described in detail herein.

[0116] refer to Fig.10 After the bonding process is completed, step S06 is performed to remove the temporary substrate 90 and flip the bonded FBAW resonator. When an isolation layer 97 is formed between the temporary substrate 90 and the second electrode layer 33, the temporary substrate 90 can be peeled off by etching the isolation layer 97; when no isolation layer 97 is formed between the temporary substrate 90 and the second electrode layer 33, the temporary substrate 90 can be removed by other methods, such as etching or mechanical grinding.

[0117] refer to Fig.11, execute step S07, after the above resonator is flipped, the second electrode layer 33' is patterned to form the second electrode 33, the first electrode 31, the piezoelectric layer 32 and the second electrode 33 constitute a piezoelectric stack structure 3, the effective resonance region includes the region where the first electrode 31, the piezoelectric layer 32 and the second electrode 33 overlap each other in a direction perpendicular to the surface of the piezoelectric layer 32, and the invalid resonance region is the region outside the effective resonance region. The second electrode 33 retains the portion located in the effective resonance region, and the method of patterning the second electrode layer 33' is the same as the method of patterning the first electrode layer 31', which will not be repeated here. Among them, the shapes of the second electrode 33 and the first electrode 31 can be the same or different. In this embodiment, the shapes of the second electrode 33 and the first electrode 31 are the same, both are irregular polygons, and the projections of the second electrode 33 and the first electrode 31 in the direction of the piezoelectric layer 32 completely overlap.

[0118] refer to Fig.11 , execute step S08 to form a second electrode lead-out structure 5, the second electrode lead-out structure 5 connects to the edge of the second electrode 33 and extends to the invalid resonance area as a second signal connection end, and forms a second gap 53 with the piezoelectric stack structure 3 at the edge of the effective resonance area. It should be noted that the second signal connection end can be used as a signal input end or a signal output end. When the first signal connection end is a signal input end, the second signal connection end is a signal output end, and vice versa. When an alternating current is connected, the first signal connection end and the second signal connection end serve as a signal input end and a signal output end respectively and are in a dynamic change process. The second electrode lead-out structure 5 can be in a planar shape or a strip shape. Specifically, when the second electrode lead-out structure 5 is in a planar shape, the area of ​​the second electrode 33 and the second electrode lead-out structure 5 can be increased, which is beneficial to reducing impedance and improving the Q value of the resonator.

[0119] Continue to refer Fig.11 In this embodiment, the second electrode lead-out structure 5 includes a second overhead portion 51 and a second overlapping portion 52. The second overhead portion 51 and the piezoelectric layer 32 and the second electrode 33 form a second gap 53. The second overlapping portion 52 connects the second overhead portion 51 and extends to the invalid resonance area. The second overlapping portion 52 is used to connect a second external signal.

[0120] The method for forming the second electrode lead-out structure 5 includes:

[0121] A second sacrificial protrusion 93 is formed at the edge of the second electrode 33 , and the second sacrificial protrusion 93 is located on the second electrode 33 and the side wall of the second electrode 33 , or the second sacrificial protrusion 93 is located on the side wall of the second electrode 33 ;

[0122] forming a second conductive layer, covering the piezoelectric layer 32 and the second sacrificial protrusion 93;

[0123] The second conductive layer is patterned to form a second electrode lead-out structure 5 .

[0124] Specifically, a second sacrificial protrusion material layer is first formed, the second sacrificial protrusion material layer covers the second electrode 33 and the piezoelectric layer 32, and the second sacrificial protrusion material layer is patterned to form a second sacrificial protrusion outside the edge of the second electrode 33 and close to the side wall of the second electrode 33, or the second sacrificial protrusion can also be located on the second electrode 33 and extend to the piezoelectric layer 32. In this embodiment, the top of the second sacrificial protrusion is higher than the surface of the second electrode 33. It should be understood that the top of the second sacrificial protrusion may not be higher than the surface of the second electrode 33. However, when the top of the second sacrificial protrusion is higher than the surface of the second electrode 33, when the second gap 53 is formed after the second sacrificial protrusion is removed, the edge of the second electrode 33 can be fully exposed in the second gap 33, which can better suppress the loss of shear waves. The shape and material of the second sacrificial protrusion refer to the shape and material of the first sacrificial protrusion, and the material of the second electrode lead-out structure 5 refers to the structure embodiment described above.

[0125] In this embodiment, the second electrode lead-out structure 5 includes a second overhead portion 51 covering the second sacrificial protrusion and a second overlapping portion 52 located on the surface of the piezoelectric layer 33, the second overlapping portion 52 extends to the periphery of the first cavity 21, the second overlapping portion 52 is electrically connected to the second external signal terminal, and the second overhead portion and the second overlapping portion are electrically connected. It should be noted that the formation method and structure of the second electrode lead-out structure are the same as the formation method and structure of the first electrode lead-out structure. The structure of the second overhead portion and the second overlapping portion refers to the structure of the first overhead portion and the first overlapping portion, and will not be repeated here.

[0126] When forming the second electrode lead-out structure 5, a second sacrificial protrusion is formed so that the second electrode lead-out structure 5, the piezoelectric layer 32 and the second electrode form a second gap 53 to expose the edge of the second electrode 33, thereby facilitating effective suppression of shear waves. In addition, the second sacrificial protrusion is formed by a sacrificial material method, which can form a support when the second electrode lead-out structure 5 is formed, thereby ensuring the structural strength of the second electrode lead-out structure and ensuring that the piezoelectric layer 32 will not be compressed and deformed, thereby ensuring the overall structural stability of the formed resonator.

[0127] In this embodiment, projections of the first electrode lead-out structure and the second electrode lead-out structure on the surface of the piezoelectric layer are staggered.

[0128] Specifically, the projections of the first overlapping portion and the second overlapping portion on the surface of the piezoelectric layer are staggered to avoid coupling effect due to potential floating and to prevent parasitic effect.

[0129] Continue to refer Fig.11, perform step S09 to remove the first sacrificial layer. When removing the first sacrificial layer, remove the sacrificial protrusion. Specifically, form a first release hole penetrating the piezoelectric layer 32 to expose the first sacrificial layer, and remove the first sacrificial layer through the first release hole; form a second release hole penetrating the electrode lead-out structure to expose the sacrificial protrusion, and remove the sacrificial protrusion through the second release hole.

[0130] In this embodiment, in order to facilitate the removal of the first sacrificial layer after forming the second electrode lead-out structure 5, it is necessary to form an air gap 321 that penetrates the piezoelectric layer 32 and connects to the first sacrificial layer when forming the piezoelectric layer 32. The air gap 321 can be formed by etching, and the structure and distribution of the air gap 321 can refer to the above-mentioned structure embodiment, which will not be repeated here.

[0131] In the process of removing the first sacrificial layer, a corresponding removal method is adopted according to the material of the first sacrificial layer. For example, when the material of the first sacrificial layer is polyimide or photoresist, an ashing method is adopted for removal. Specifically, at a temperature of 250 degrees Celsius, oxygen chemically reacts with the material of the first sacrificial layer through the air gap 321, and the generated gas substances are volatilized. When the material of the first sacrificial layer is low-temperature silicon dioxide, hydrofluoric acid solvent is used to react with low-temperature silicon dioxide to remove it, so as to form a first cavity 121. The shape of the first cavity 121 is the same as that of the first sacrificial layer. It should be noted that when the first sacrificial protrusion is the same as the material of the first sacrificial layer, the first sacrificial protrusion and the first sacrificial layer can be removed simultaneously through the air gap 321. In addition, after removing the first sacrificial layer, the second sacrificial protrusion needs to be removed. The removal method can refer to the removal method of the first sacrificial layer, which will not be repeated here.

[0132] When the first sacrificial layer, the first sacrificial protrusion and the second sacrificial protrusion are removed, the first cavity 121, the first gap 43 and the second gap 53 are formed respectively. The air gap 321 cooperates with the first gap 43 and the second gap 53 to suppress shear waves.

[0133] In this embodiment, the projections of the first gap 43 and the second gap 53 on the piezoelectric layer 32 form a closed ring or a ring with a gap, which increases the contact area between the first electrode edge and the second electrode edge and the air, is more conducive to preventing shear wave leakage and improving the Q value of the resonator.

[0134] An air gap 321 penetrating the piezoelectric layer 32 and communicating with the first cavity 121 is also provided at the edge of the effective resonance region, so that part of the edge of the piezoelectric layer 32 is exposed to the air, thereby effectively suppressing the shear wave.

[0135] In this embodiment, the projections of the air gap 321 , the first gap 43 and the second gap 43 on the piezoelectric layer 32 are staggered and form a closed ring or a ring with gaps, which can better suppress shear waves.

[0136] In this embodiment, a first electrode 31 and a first electrode lead-out structure 4 are first formed on the first surface of the piezoelectric layer 32, and then a second electrode 33 and a second electrode lead-out structure 5 are formed on the second surface of the piezoelectric layer 32. This process of patterning electrodes on both sides of the piezoelectric layer avoids etching of the piezoelectric layer during the electrode formation process, ensures the integrity and flatness of the piezoelectric layer 32, reduces the impact on the piezoelectric layer, and thus improves the performance of the resonator. In addition, this method is compatible with the main process of the resonator and has a simple process.

[0137] In other embodiments, reference Fig.12 , further comprising: forming a first protrusion 6 on the first electrode 31, the first protrusion 6 being distributed along the boundary of the effective resonance region. When etching to form the first electrode lead-out structure 4, the first protrusion 6 is also etched to form the first protrusion 6, and the first protrusion 6 is made of the same material as the first electrode lead-out structure 4; or, the first protrusion 6 is formed after the first electrode lead-out structure 4 is formed; or, the first protrusion 6 is formed after the first electrode 31 is formed and before the first electrode lead-out structure 4 is formed.

[0138] Continue to refer Fig.12 , further comprising: forming a second protrusion 7 on the second electrode 33, the second protrusion 7 being distributed along the boundary of the effective resonance region. When etching to form the second electrode lead-out structure 5, the second protrusion 7 is also etched to form the second protrusion 7, and the second protrusion 7 is made of the same material as the second electrode lead-out structure 5; or, the second protrusion 7 is formed after the second electrode lead-out structure 5 is formed; or, the second protrusion 7 is formed after the second electrode 33 is formed and before the second electrode lead-out structure 5 is formed. In this embodiment, the structure, material, distribution and beneficial effects of the first protrusion 6 and the second protrusion 7 can refer to the first protrusion 6 and the second protrusion 7 described in the previous structural embodiment, and will not be repeated here.

[0139] refer to Fig.13 In other embodiments of the present invention, after forming the first electrode 31, a first dielectric layer 95 is formed on the piezoelectric layer 32 in the invalid resonance region, which is separated from the first electrode 31. The first dielectric layer 95 is formed between the first substrate 1 and the piezoelectric layer 32. The first dielectric layer 95 and the first overlapping portion 42 surround the first electrode 31. It should be noted that the first dielectric layer 95 can be formed before or after forming the first electrode lead-out structure 4. Similarly, after forming the second electrode 32, a second dielectric layer 96 is formed on the piezoelectric layer 32 in the invalid resonance region, which is separated from the second electrode 33. The second dielectric layer 96 and the second overlapping portion 52 surround the second electrode 33. It should be noted that the second dielectric layer 96 can be formed before or after forming the second electrode lead-out structure 5.

[0140] The distribution of the first dielectric layer 95 relative to the first overlap portion 42, the beneficial effects, and the material of the first dielectric layer 95 can be referred to as described in the previous structural embodiment. The distribution of the second dielectric layer 96 relative to the second overlap portion 52, the beneficial effects, and the material of the second dielectric layer 96 can be referred to as described in the previous structural embodiment. The setting of the first dielectric layer 95 relative to the second dielectric layer 96 and its beneficial effects can be referred to as described in the previous structural embodiment, and will not be repeated here.

[0141] In other embodiments, Figure 14-16 As shown, a top cover 8 may be formed on the piezoelectric stack structure 3 to prevent the layers exposed to the upper space from being contaminated by the external environment. The top cover 8 has a second cavity 811 inside, and the second electrode 33 is located in the second cavity 811 .

[0142] At the same time, the formed second cavity 811 cooperates with the first cavity 121, so that the longitudinal waves between the first electrode 31, the piezoelectric layer 32 and the second electrode 33 are transmitted to the first cavity 121 or the second cavity 811 and then reflected back into the effective resonance area, thereby improving the utilization rate of the sound waves.

[0143] refer to Fig.14 The top cover 8 may further include a bonding layer 81 and a second substrate 82 .

[0144] In one embodiment, reference Figure 15-16 , the method of forming the top cover 8 includes:

[0145] S1: forming a second sacrificial layer 94, the second sacrificial layer 94 covers the second electrode 33 and the second electrode lead-out structure 5 located at the boundary of the effective resonance region;

[0146] S2: forming a bonding layer 81 to cover the second sacrificial layer 94 and the piezoelectric stack structure 3;

[0147] S3: removing the second sacrificial layer 94 to form a second cavity 811;

[0148] S4 : forming a second substrate 82 on the bonding layer 81 .

[0149] refer to Fig.11 as well as Fig.15 , execute step S1, wherein after executing step S08, the following is formed Fig.15 The second sacrificial layer 94 shown in the figure covers the second electrode 33 and the second electrode lead-out structure 5 located at the boundary of the effective resonance region. The second sacrificial layer 94 may cover part or all of the second overhead portion 51, or may not cover the second overhead portion 51. The method of depositing the second sacrificial layer 94 may refer to the method of depositing the first sacrificial layer 91 described above, and the material of the second sacrificial layer 94 may refer to the material of the first sacrificial layer 91, which will not be described in detail here.

[0150] refer to Fig.16 When executing step S2, the second sacrificial layer of the bonding layer 81 is formed by a deposition process. The second sacrificial layer can cover the entire overhead portion, or can cover part of the second overhead portion, or can not cover the second overhead portion. Release holes 812 are formed on the bonding layer. The number, size, and shape of the release holes 812 are not specifically limited. The sacrificial layer material can be completely removed. The cross-section of the release hole 812 can be trapezoidal, rectangular, circular, elliptical, etc., and is formed by dry etching.

[0151] Continue to refer Fig.16 , perform step S3, when removing the second sacrificial layer 94, it is necessary to adopt a corresponding removal method according to its material, which will not be repeated here. It should be noted that the first sacrificial protrusion, the second sacrificial protrusion and the first sacrificial layer 91 can be removed simultaneously with the second sacrificial layer 94 in this step. At this time, the first sacrificial protrusion 92, the second sacrificial protrusion 93, the first sacrificial layer and the second sacrificial layer use the same sacrificial material.

[0152] Continue to refer Fig.16 , perform step S4, the bonding method of the bonding layer 81 and the second substrate 82 can refer to the bonding method of the base 11 and the support layer 12, which will not be repeated here.

[0153] In this embodiment, the second cavity 811 is formed by adopting a second sacrificial layer 94, so that in the process of forming the second substrate 82, the first sacrificial layer 91, the first sacrificial protrusion 92, and the second sacrificial protrusion 93 are combined to form a support, thereby preventing the piezoelectric stack structure 3 from being subjected to uneven force and being compressed and deformed, thereby ensuring that the resonator finally formed has good overall structural stability.

[0154] In other embodiments, the top cover 8 may also be an integrated structure, the top cover 8 is etched to form the second cavity 811, and the top cover 8 is bonded to the piezoelectric stack structure. It should be noted that the first sacrificial protrusion 92 and the second sacrificial protrusion 93 need to be removed before forming the top cover 8. By first etching the second substrate 82 to form the second cavity 811, and then bonding the second substrate 82 to the piezoelectric layer 32, the integrity of the piezoelectric layer 32 is avoided from being destroyed when etching the second cavity 811, thereby ensuring the structural strength of the piezoelectric layer 32.

[0155] To sum up, in the process of manufacturing the resonator, by using separate first electrode lead-out structures and second electrode lead-out structures on the first electrode side and the second electrode side respectively, the first electrode lead-out structure and the second electrode lead-out structure respectively form a first gap and a second gap in the boundary area of ​​the effective resonance zone, and the first gap and the second gap can achieve the effect of eliminating the boundary clutter of the effective resonance zone, thereby improving the Q value of the resonator. The first electrode lead-out structure and the second electrode lead-out structure use metal materials with lower resistivity and better thermal conductivity, which can reduce impedance and enhance thermal conductivity.

[0156] Furthermore, the piezoelectric layer is provided with a gap gap, so that the edge of the piezoelectric layer is exposed to the air, which can suppress shear wave loss; when the projections of the gap gap, the first gap and the second gap on the piezoelectric layer are staggered and form a closed ring, the shear wave loss can be better suppressed.

[0157] Furthermore, when the piezoelectric layer is a complete film layer, the structural strength of the resonator can be increased; the piezoelectric layer is formed on a flat electrode layer, which can make the piezoelectric layer have a better lattice orientation, improve the piezoelectric properties of the piezoelectric layer, and thus improve the overall performance of the resonator.

[0158] Furthermore, a first protrusion is arranged on the surface of the first electrode and / or a second protrusion is arranged on the surface of the second electrode, and an acoustic impedance mismatch zone is formed in the area where the first protrusion and the second protrusion are located, which can achieve acoustic impedance mismatch between the boundary of the effective resonance zone and the inside of the effective resonance zone; the projection of the first protrusion and the first overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap, or the projection of the second protrusion and the second overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap, which can jointly suppress lateral noise leakage and further improve the quality factor of the resonator.

[0159] Furthermore, a first dielectric layer and a second dielectric layer are formed on the upper and lower surfaces of the piezoelectric layer respectively, which can improve the bonding effect when a top cover is subsequently formed. Meanwhile, the arrangement of the first dielectric layer and the second dielectric layer can also improve the overall mechanical strength of the resonator.

[0160] The thin film bulk acoustic wave resonator manufacturing method of the present invention adopts the process of electrode patterning on both sides of the piezoelectric layer to ensure that the piezoelectric layer is not etched during the entire manufacturing process, thereby ensuring the integrity and flatness of the piezoelectric layer, and further ensuring that the piezoelectric layer has good piezoelectric characteristics.

[0161] It should be noted that the various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the structural embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0162] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A thin film bulk acoustic resonator, characterized in that: include: a first substrate, wherein a first cavity is provided in the first substrate; A piezoelectric stack structure, comprising, from bottom to top, a first electrode, a piezoelectric layer, and a second electrode stacked in sequence, wherein the edges of the first electrode and the second electrode are both located within the boundary of an area enclosed by the first cavity, and an effective resonance area includes an area where the first electrode, the piezoelectric layer, and the second electrode overlap each other in a direction perpendicular to a surface of the piezoelectric layer; the piezoelectric layer is a complete film layer, and both the upper and lower surfaces of the piezoelectric layer are planes, covering the area enclosed by the first cavity and extending outside the area enclosed by the first cavity; A first electrode lead-out structure, connected to an edge of the first electrode away from a surface of one side of the piezoelectric layer and extending to an invalid resonance region as a first signal connection end, and a first gap is formed between the edge of the effective resonance region and the side surface of the first electrode and the surface of the piezoelectric layer; A second electrode lead-out structure connects the edge of the second electrode away from the surface of one side of the piezoelectric layer and extends to the invalid resonance area as a second signal connection end, and a second gap is formed between the edge of the effective resonance area and the side of the second electrode and the surface of the piezoelectric layer.

2. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: The projections of the first electrode lead-out structure and the second electrode lead-out structure on the surface of the piezoelectric layer are staggered with each other.

3. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: Projections of the first recess and the second recess on the piezoelectric layer form a closed ring or a ring with gaps.

4. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: The first electrode lead-out structure includes: a first overhead portion surrounding the first gap, a first overlap portion connecting the first overhead portion and extending to the invalid resonance region, the first overlap portion serving as the first signal connection end; and / or, The second electrode lead-out structure includes: a second overhead portion surrounding the second gap, and a second overlapping portion connecting the second overhead portion and extending to the invalid resonance region, wherein the second overlapping portion serves as the second signal connection end.

5. The thin film bulk acoustic resonator according to claim 4, characterized in that: The surface of the first overlapping portion facing the piezoelectric layer is flush with the surface of the first electrode facing the piezoelectric layer; and / or, A surface of the second overlapping portion facing the piezoelectric layer is flush with a surface of the second electrode facing the piezoelectric layer.

6. The thin film bulk acoustic wave resonator according to claim 4, characterized in that: The first overlapping portion surrounds the outer periphery of the first electrode, or the first overlapping portion is disposed on a portion of the outer periphery of the first electrode; The first overhead portion surrounds the outer circumference of the first electrode; The second overlapping portion surrounds the outer circumference of the second electrode, or the second overlapping portion is disposed on a portion of the outer circumference of the second electrode; The second overhead portion surrounds the outer circumference of the second electrode.

7. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: The material of the first electrode lead-out structure or the second electrode lead-out structure is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, and copper.

8. The thin film bulk acoustic wave resonator according to claim 4, characterized in that: It also includes a first protrusion and / or a second protrusion, wherein the first protrusion is located on the first electrode and distributed along the boundary of the effective resonance area, and the projection of the first protrusion and the first overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap; The second protrusion is located on the second electrode and distributed along the boundary of the effective resonance area. The projections of the second protrusion and the second overhead portion on the surface of the piezoelectric layer are closed or ring-shaped with gaps.

9. The thin film bulk acoustic wave resonator according to claim 8, characterized in that: The material of the first protrusion and the second protrusion includes a dielectric material; or, The material of the first protrusion is the same as that of the first electrode; and / or the material of the second protrusion is the same as that of the second electrode.

10. The thin film bulk acoustic wave resonator according to claim 4, characterized in that: Also includes a first dielectric layer and a second dielectric layer; The first dielectric layer is located between the first substrate and the piezoelectric layer, the first dielectric layer is located in the invalid resonance region and is separated from the first electrode, and the first dielectric layer and the first overlapping portion surround the first electrode; The second dielectric layer is located on the piezoelectric layer, the second dielectric layer is located in the invalid resonance region and is separated from the second electrode, and the second dielectric layer and the second overlapping portion surround the second electrode.

11. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: An air gap penetrating through the piezoelectric layer and communicating with the first cavity is also provided at the edge of the effective resonance area.

12. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: The device further comprises a top cover, wherein the top cover has a second cavity therein, the second cavity is located above the first cavity, and the second electrode is located in the second cavity.

13. The thin film bulk acoustic wave resonator according to claim 1, characterized in that: The first substrate includes a base and a support layer. The support layer and the piezoelectric stacked structure are sequentially stacked on the base, and the first cavity is arranged in the support layer.

14. A method for manufacturing a thin film bulk acoustic wave resonator, characterized in that: include: providing a temporary substrate; forming a second electrode layer, a piezoelectric layer and a first electrode in sequence on the temporary substrate, wherein the first electrode is located in an effective resonance region; forming a first electrode lead-out structure, wherein the first electrode lead-out structure is connected to an edge of the first electrode away from the surface of one side of the piezoelectric layer and extends to an invalid resonance region as a first signal connection end, and a first gap is enclosed between the boundary of the effective resonance region and the surface of the piezoelectric layer and the side of the first electrode; forming a first sacrificial layer to cover the first electrode and the first electrode lead-out structure located at the boundary of the effective resonance region; forming a first substrate covering the first sacrificial layer and the piezoelectric layer; removing the temporary substrate; The second electrode layer is patterned to form a second electrode; the second electrode, the piezoelectric layer and the first electrode form a piezoelectric stacked structure, and the effective resonance region includes a region where the first electrode, the piezoelectric layer and the second electrode overlap each other in a direction perpendicular to a surface of the piezoelectric layer; forming a second electrode lead-out structure, wherein the second electrode lead-out structure is connected to an edge of the second electrode away from the surface of one side of the piezoelectric layer and extends to the invalid resonance region as a second signal connection end, and a second gap is enclosed between the edge of the effective resonance region and the surface of the piezoelectric layer and the side of the second electrode; The first sacrificial layer is removed to form a first cavity, the piezoelectric layer is a complete membrane layer, the upper surface and the lower surface of the piezoelectric layer are both planes, covering the area enclosed by the first cavity and extending outside the area enclosed by the first cavity.

15. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: The projections of the first electrode lead-out structure and the second electrode lead-out structure on the surface of the piezoelectric layer are staggered with each other.

16. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: Projections of the first recess and the second recess on the piezoelectric layer form a closed ring or a ring with gaps.

17. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 16, characterized in that: The method of forming a first electrode lead-out structure includes: forming a first sacrificial protrusion at an edge of the first electrode, wherein the first sacrificial protrusion is located on the first electrode and a side wall of the first electrode, or the first sacrificial protrusion is located on a side wall of the first electrode; forming a first conductive layer covering the piezoelectric layer and the first sacrificial protrusion; The first conductive layer is patterned to form the first electrode lead-out structure.

18. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 16, characterized in that: The method of forming the second electrode lead-out structure includes: forming a second sacrificial protrusion at the edge of the second electrode, wherein the second sacrificial protrusion is located on the second electrode and the side wall of the second electrode, or the second sacrificial protrusion is located on the side wall of the second electrode; forming a second conductive layer covering the piezoelectric layer and the second sacrificial protrusion; The second conductive layer is patterned to form the second electrode lead-out structure.

19. The method for manufacturing a thin film bulk acoustic resonator according to claim 17 or 18, characterized in that: When removing the first sacrificial layer, removing the sacrificial protrusion; forming a first release hole penetrating through the piezoelectric layer to expose the first sacrificial layer, and removing the first sacrificial layer through the first release hole; A second release hole is formed to penetrate the electrode lead-out structure and expose the sacrificial protrusion, and the sacrificial protrusion is removed through the second release hole.

20. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: Also includes: forming a first protrusion on the first electrode, wherein the first protrusion is distributed along a boundary of the effective resonance area; When etching to form the first electrode lead-out structure, etching to form the first protrusion is also performed, and the first protrusion is made of the same material as the first electrode lead-out structure; Alternatively, the first protrusion is formed after the first electrode lead-out structure is formed; Alternatively, the first protrusion is formed after forming the first electrode and before forming the first electrode lead-out structure.

21. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 20, characterized in that: The projections of the first protrusion and the first gap on the surface of the piezoelectric layer form a closed ring or a ring with a gap.

22. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 20, characterized in that: The material of the first protrusion includes a dielectric material; or, The material of the first protrusion is the same as that of the first electrode.

23. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: Also includes: forming a second protrusion on the second electrode, wherein the second protrusion is distributed along a boundary of the effective resonance area; When etching to form the second electrode lead-out structure, etching to form the second protrusion is also performed, and the second protrusion is made of the same material as the second electrode lead-out structure; Alternatively, the second protrusion is formed after the second electrode lead-out structure is formed; Alternatively, the second protrusion is formed after forming the second electrode and before forming the second electrode lead-out structure.

24. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 23, characterized in that: Also includes: The projections of the second protrusion and the second gap on the surface of the piezoelectric layer form a closed ring or a ring with a gap.

25. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 24, characterized in that: The material of the second protrusion includes a dielectric material; or, The material of the second protrusion is the same as that of the second electrode.

26. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: Also includes: After forming the first electrode, forming a first dielectric layer on the piezoelectric layer in the invalid resonance region, the first dielectric layer being separated from the first electrode, the first dielectric layer being formed between the first substrate and the piezoelectric layer, and the first dielectric layer being continuously connected to the first overlapping portion; After the second electrode is formed, a second dielectric layer is formed on the piezoelectric layer in the invalid resonance region, which is separated from the second electrode, and the second dielectric layer is continuously connected to the second overlapping portion.

27. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: After forming the second electrode lead-out structure, the method further includes: The piezoelectric layer at the edge of the effective resonance region is etched to form an air gap that penetrates the piezoelectric layer and communicates with the first cavity.

28. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 27, characterized in that: Projections of the air gap, the first gap, and the second gap on the piezoelectric layer are staggered with each other and form a closed ring or a ring with gaps.

29. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: Also includes: A top cover is formed on the piezoelectric stack structure, wherein the top cover includes a second cavity, and the second electrode is located in the second cavity.

30. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: The material of the first sacrificial layer includes: phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist.

31. The method for manufacturing a thin film bulk acoustic wave resonator according to claim 14, characterized in that: The material of the first sacrificial layer is polyimide or photoresist, which is removed by ashing method; or, The material of the first sacrificial layer is low-temperature silicon dioxide, which is removed by using a hydrofluoric acid solvent.

Images