Method for manufacturing thin film bulk acoustic resonator and filter

Abstract

The present invention relates to a method for manufacturing a thin film bulk acoustic wave resonator and a filter, comprising: forming a first electrode, a piezoelectric layer, and a second electrode; forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode; forming an electrode lead-out structure having an arched bridge on the electrode having the annular groove; forming a support layer on the first electrode; patterning the support layer to form a first cavity penetrating the support layer, with the arched bridge of the electrode lead-out structure located within the first cavity; providing a first substrate to cover the first cavity; removing an annular sacrificial protrusion to form an annular gap, with the annular gap and the annular groove facing each other. The present invention defines the boundary of an effective resonance region by the region where the annular gap of the electrode lead-out structure is located, and makes the end of the corresponding electrode at the boundary of the effective resonance region contact the gas in the gap through the annular groove, thereby achieving the effect of eliminating boundary noise of the electrode in the effective resonance region, thereby improving the Q value of the resonator.

Description

Technical Field

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

[0002] Since the development of analog RF communication technology in the early 1990s, RF front-end modules have gradually become core components of communications equipment. Among all RF front-end modules, filters have become the component with the fastest 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 imposed more stringent standards on various aspects of RF filter performance. The performance of the filter is determined by the resonator units that make up the filter. Among existing filters, film bulk acoustic resonators (FBARs) are one of the most suitable filters for 5G applications due to their small size, low insertion loss, high out-of-band suppression, high quality factor, high operating frequency, high power handling capacity, and good resistance to electrostatic shock.

[0003] Typically, a FBAW resonator consists of two thin-film electrodes with a piezoelectric film layer between them. Its operating principle is that the piezoelectric film layer vibrates under an alternating electric field. This vibration excites a bulk acoustic wave that propagates along the thickness of the piezoelectric film layer. This sound wave is reflected at the interface between the upper and lower electrodes and the air, and then reflects back and forth within the film, forming an oscillation. When the sound wave propagates in the piezoelectric film layer at an odd multiple of half the wavelength, it forms a standing wave oscillation.

[0004] However, the quality factor (Q) of currently manufactured cavity-type thin film bulk acoustic 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 method for manufacturing a thin film bulk acoustic wave resonator and a filter, 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 method for manufacturing a thin film bulk acoustic resonator, comprising:

[0007] forming a first electrode, a piezoelectric layer, and a second electrode, wherein the piezoelectric layer is located between the first electrode and the second electrode, and forming an annular groove penetrating the corresponding electrode in at least one of the first electrode and the second electrode;

[0008] An electrode lead-out structure having an arched bridge is formed on an electrode having an annular groove, comprising: forming an annular sacrificial protrusion; forming an electrode lead-out structure covering the annular sacrificial protrusion and having its edge overlapped on the edge of the electrode in the effective resonance region;

[0009] forming a supporting layer on the first electrode;

[0010] patterning the support layer to form a first cavity penetrating the support layer;

[0011] Providing a first substrate, wherein the first substrate covers the first cavity, and the arched bridge of the electrode lead-out structure is located within the first cavity;

[0012] The annular sacrificial protrusion is removed to form an annular gap, which is opposite to the annular groove.

[0013] The present invention also provides a filter comprising at least one thin film bulk acoustic resonator formed by the above-mentioned method for manufacturing a thin film bulk acoustic resonator.

[0014] The beneficial effects of the method for manufacturing a thin film bulk acoustic resonator of the present invention are:

[0015] An electrode lead-out structure with an arched bridge structure is formed by forming an annular sacrificial protrusion on the corresponding electrode. After removing the annular sacrificial protrusion, an annular gap is formed to define the scope of the effective resonance region. Then, an annular groove is formed through the corresponding electrode by etching the corresponding electrode. This not only simplifies the formation process of the electrode lead-out structure, but also separates the electrodes located inside and outside the annular groove, and electrically connects the disconnected electrodes through the electrode lead-out structure. In addition, the annular groove exposes the boundary of the corresponding electrode to the annular gap formed by the arched bridge, thereby achieving the effect of eliminating the electrode boundary noise in the effective resonance region, thereby improving the Q value of the resonator.

[0016] Furthermore, forming the first cavity by etching the support layer can simplify the formation process and reduce manufacturing costs.

[0017] Furthermore, the piezoelectric layer is formed on a flat electrode or carrier substrate so that the upper and lower surfaces of the piezoelectric layer are both flat, ensuring that the piezoelectric layer has a good lattice orientation, improving the piezoelectric properties of the piezoelectric layer, and thereby improving the performance of the resonator.

[0018] Furthermore, the impedance of the electrode lead-out structure is lower than the impedance of the corresponding electrode, so as to reduce the electrode impedance, make the electrode lead-out structure have better conductivity, and improve the conductivity.

[0019] Furthermore, the electrode lead-out structure and the corresponding electrode without an electrode lead-out structure or the electrode lead-out structures respectively arranged on the first electrode and the second electrode are at least partially staggered with each other in the outer area of ​​the arch bridge, which can avoid high-frequency coupling problems caused by potential floating, prevent the formation of parasitic capacitance, and is conducive to improving the quality factor of the resonator.

[0020] Furthermore, the first electrode and / or the second electrode extends from the effective resonance region to the first substrate outside the first cavity, which can improve the structural strength of the resonator. In addition, the electrode lead-out structure formed on the corresponding electrode also extends from the effective resonance region to the first substrate outside the first cavity, so as to improve the structural strength of the resonator.

[0021] Furthermore, the piezoelectric layer is a complete film layer, which can ensure the structural strength of the resonator and improve the yield rate of the resonator.

[0022] Furthermore, a first groove is provided in the piezoelectric layer, so that the edge of the piezoelectric layer is exposed to the gas, which can suppress the shear wave loss of the piezoelectric layer. When the first groove is entirely located within the annular gap, the Q value of the resonator can be better improved.

[0023] The filter of the present invention has the following beneficial effects:

[0024] The thin film bulk acoustic resonators are connected to form a filter, thereby ensuring that the filter has good structural stability. Since the electrode impedance of the resonator is low, the conductivity of the filter can be improved, and the accuracy of filtering can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0026] Figure 1 Flowchart of a method for manufacturing a thin film bulk acoustic resonator according to Example 1 of the present invention;

[0027] Figures 2 to 5 Schematic diagrams showing the structures corresponding to different steps of the method for manufacturing a thin film bulk acoustic resonator according to Example 1 of the present invention;

[0028] Figures 6 to 8 A schematic structural diagram corresponding to different steps of another method for manufacturing the thin film bulk acoustic resonator formed in Example 1 of the present invention is shown;

[0029] Figures 9 to 11 A schematic structural diagram corresponding to different steps of another method for manufacturing the thin film bulk acoustic resonator formed in Example 1 of the present invention is shown;

[0030] Figure 12 Schematic diagram of the structure of a thin film bulk acoustic resonator manufactured according to the method for manufacturing a thin film bulk acoustic resonator in Example 2;

[0031] Figure 13-19Schematic diagram of the structure of a thin film bulk acoustic resonator manufactured according to the method for manufacturing a thin film bulk acoustic resonator in Example 3;

[0032] Figure 20 FIG. 4 is a schematic structural diagram of a thin film bulk acoustic wave resonator manufactured according to the method for manufacturing a thin film bulk acoustic wave resonator in Example 4. FIG.

[0033] Description of reference numerals:

[0034] 11. First substrate; 12. Support layer; 121. First cavity; 21. First electrode; 22. Piezoelectric layer; 23. Second electrode; 24. Annular groove; 25. First groove; 3. Electrode lead structure; 31. Arch bridge; 32. Annular gap; 32', Annular sacrificial protrusion; 4. Carrying substrate; 5. Second substrate; 51. Acoustic reflector. DETAILED DESCRIPTION

[0035] The following is a detailed description of the thin film bulk acoustic resonator and its fabrication method of the present invention, in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and drawings. However, it should be noted that the technical solutions of the present invention can be implemented in a variety of different forms and are not limited to the specific embodiments described herein. The drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0036] 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 chronological sequence. It is to be understood that, where appropriate, these terms used in this manner are interchangeable, for example, to enable the embodiments of the invention described herein to operate in an order other than that described or shown herein. Similarly, if the method described herein comprises a series of steps, the order in which the steps are presented herein is not necessarily the only order in which the 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 a component in a particular figure is the same as a component 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.

[0037] Example 1

[0038] Figure 1 Flow chart of the method for manufacturing a thin film bulk acoustic resonator according to embodiment 1 of the present invention, referring to Figure 1 Embodiment 1 provides a method for manufacturing a thin film bulk acoustic wave resonator. The method for manufacturing a thin film bulk acoustic wave resonator includes:

[0039] S01: forming a first electrode, a piezoelectric layer, and a second electrode, wherein the piezoelectric layer is located between the first electrode and the second electrode;

[0040] S02: forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode;

[0041] S03: forming an electrode lead-out structure having an arched bridge on the electrode having the annular groove, including: forming an annular sacrificial protrusion; forming an electrode lead-out structure covering the annular sacrificial protrusion and having an edge overlapping the edge of the electrode in the effective resonance region;

[0042] S04: forming a support layer on the first electrode; patterning the support layer to form a first cavity penetrating the support layer, wherein the arched bridge of the electrode lead-out structure is located within the first cavity;

[0043] S05: providing a first substrate, wherein the first substrate covers the first cavity;

[0044] S06: removing the annular sacrificial protrusion to form an annular gap, where the annular gap is opposite to the annular groove.

[0045] Steps S0N do not represent a sequential order.

[0046] An electrode lead structure is provided on one of the first electrode 21 and the second electrode 24. The following describes a method for manufacturing the thin film bulk acoustic resonator by taking the electrode lead structure formed on the first electrode 31 as an example. Figures 2 to 5 This is a schematic structural diagram corresponding to the corresponding steps of the method for manufacturing a thin film bulk acoustic resonator of this embodiment, with reference to Figures 2 to 5 The method for manufacturing the thin film bulk acoustic resonator provided by this embodiment is described in detail.

[0047] refer to Figures 2 to 5 In this embodiment, the method for forming the first electrode 21, the piezoelectric layer 22 and the second electrode 24 includes: providing a carrier substrate 4; forming the second electrode 23, the piezoelectric layer 22 and the first electrode 21 in sequence on the carrier substrate 4; after the first substrate 11 covers the first cavity 121 on the support layer 12, removing the carrier substrate 4; forming an electrode lead-out structure on the first electrode, specifically including: forming an electrode lead-out structure on the first electrode after forming the first electrode and before forming the support layer.

[0048] refer to Figure 2 , providing a carrier substrate 4, which can be a semiconductor material, such as 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.

[0049] Continue to refer Figure 2, forming the second electrode 23, the piezoelectric layer 22 and the first electrode 21 on the carrier substrate 4 in sequence, wherein the first electrode 21 and the second electrode 23 can be formed by physical vapor deposition process and etching process, and the four sides of the first electrode 21 and / or the second electrode 23 extend to the supporting layer 12 outside the first cavity formed subsequently to improve the structural strength of the resonator. When the first electrode 21 and the second electrode 23 both extend from the effective resonance region to the first cavity 121 or the first substrate 1 outside the acoustic reflector 51, the resonator has better structural strength. The piezoelectric layer 22 can be deposited and formed using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition. By forming the piezoelectric layer 22 on the flat second electrode 23, the upper and lower surfaces of the piezoelectric layer 22 are both planes, thereby ensuring that the piezoelectric layer 22 has a good lattice orientation, improving the piezoelectric properties of the piezoelectric layer 22, and thereby improving the overall performance of the resonator. It should be noted that the periphery of the first electrode 21 is the outer edge of its overall structure, the periphery of the second electrode 23 is the outer edge of its overall structure, and the effective resonance region is the region surrounded by the annular gap formed subsequently.

[0050] In other embodiments, when forming the first electrode 21 and / or forming the second electrode 23, the corresponding electrodes can also be etched so that part of the first electrode 21 and / or the second electrode 23 extends to the support layer 12 outside the first cavity. At this time, in order to ensure the structural strength of the resonator, the electrodes partially extending to the periphery of the first cavity 121 on the first substrate 1 are symmetrically distributed to ensure the support strength, so that the electrode covers part or all of the first cavity.

[0051] The materials of the first electrode 21 and the second electrode 23 can be any suitable conductive material or semiconductor material known in the art. The conductive material can be a metal material having conductive properties, for example, made of one of the metals selected from the group consisting of 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. The semiconductor material can be, for example, Si, Ge, SiGe, SiC, SiGeC, etc. The material of the piezoelectric layer 22 can be a piezoelectric material having a wurtzite crystal structure, such as aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz, potassium niobate (KNbO3), or lithium tantalate (LiTaO3), or a combination thereof. When the material of the piezoelectric layer 22 is aluminum nitride (AlN), the piezoelectric layer 22 may further include a rare earth metal, such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). In addition, when the material of the piezoelectric layer 22 is aluminum nitride (AlN), the piezoelectric layer 22 may further include a transition metal, such as at least one of zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf).

[0052] Continue to refer to Figure 2 Before forming the annular sacrificial protrusion, the first electrode 21 is etched to form an annular groove 24. The annular groove 24 is a closed annular shape, so that the first electrode 21 is disconnected at the position of the annular groove 24, thereby facilitating the connection of the disconnected first electrode 21 through the subsequently formed electrode lead-out structure 3. Since the impedance of the subsequently formed electrode lead-out structure 3 is lower than the impedance of the first electrode 21, the impedance of the first electrode 21 can be reduced. In addition, the annular groove 24 can also expose the boundary of the first electrode 21 to the subsequently formed annular gap 32, thereby achieving the effect of eliminating the electrode boundary noise in the effective resonance region, thereby improving the Q value of the resonator. The effective resonance region is the area surrounded by the annular gap formed by the arched bridge structure of the subsequently formed electrode lead-out structure.

[0053] In this embodiment, during the process of etching to form the annular groove 24, the piezoelectric layer 22 may also be etched to form a first groove 25 that penetrates the piezoelectric layer 22. The first groove 25 penetrates the piezoelectric layer 22, so that the end surface of the piezoelectric layer 22 and the gas in the first groove 25 form a reflective interface, thereby effectively suppressing the leakage of acoustic waves in the piezoelectric layer 22, avoiding parasitic resonance, and improving the quality factor of the resonator. In other embodiments, after forming the piezoelectric layer 22, the piezoelectric layer 22 may be etched to form the first groove 25, and then a sacrificial material may be filled in the first groove 25 so that its upper surface is flush with the upper surface of the piezoelectric layer 22. The first electrode 21 may then be formed thereon, and the first electrode 21 may be etched to form an annular groove. The sacrificial material filled in the first groove 25 may be removed so that the formed annular groove 24 is opposite to the first groove 25.

[0054] Specifically, the projection of the first groove 25 on the surface of the piezoelectric layer 22 can partially overlap with the projection of the annular groove 24 on the surface of the piezoelectric layer 22, or the projection of the first groove 25 on the surface of the piezoelectric layer 22 is completely within the projection range of the annular groove 24 on the surface of the piezoelectric layer 22. In this embodiment, when the first groove 25 and the annular groove 24 are formed synchronously, the projection of the first groove 25 on the surface of the piezoelectric layer 22 completely overlaps with the projection of the annular groove 24 on the surface of the piezoelectric layer 22, and the acoustic wave suppression effect is better at this time. In addition, the first groove 25 is a closed ring, and the piezoelectric layer 22 inside the annular gap 32 and the piezoelectric layer 22 outside the annular gap 32 are isolated from each other; or the first groove 25 is an intermittent ring, and the piezoelectric layer 32 inside the annular gap 32 is isolated from the piezoelectric layer outside the annular gap 32 by the discontinuity. When the first groove 25 is a closed ring, the acoustic wave suppression effect is better.

[0055] Reference Figure 3 A first sacrificial material is deposited on the first electrode 21. The first sacrificial material fills the annular groove and the first groove and covers the portion of the first electrode 21 located around the annular groove. The first sacrificial layer material includes phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, amorphous carbon, polyimide, or photoresist. The first sacrificial layer material on the first electrode 21 is patterned to form an annular sacrificial protrusion 32'. The annular sacrificial protrusion 32' is a continuous structure that forms a closed ring. The boundary of the ring defines the boundary of the resonator's effective resonant region.

[0056] Continue to refer to Figure 3, an electrode lead-out structure 3 is formed on the first electrode 21, which covers the annular sacrificial protrusion 32' and has its edge overlapped on the edge of the first electrode 21 in the effective resonance region. Specifically, the electrode lead-out structure 3 is formed on the first electrode 21, and the electrode lead-out structure 3 covers the first electrode 21 and the annular sacrificial protrusion 32' formed on the first electrode 21, and extends to the support layer 12 outside the first cavity. It should be noted that the deposited conductive material covers part of the first electrode 21 and the annular sacrificial protrusion 32' and the first electrode 21 on the periphery of the annular sacrificial protrusion 32', and extends to all sides of the first electrode 21. The annular sacrificial protrusion 32' forms a closed ring to define the range of the effective resonance region by the boundary of the annular sacrificial protrusion 32'. In addition, the formed electrode lead-out structure 3 and the second electrode 23 respectively have a first portion extending outside the effective resonance region to serve as an electrode connection end.

[0057] In the actual manufacturing process, since the electrode lead-out structure 3 only needs to connect the first electrode 21 disconnected by the annular groove, the conductive material can also be etched to remove part of the conductive material located in the area surrounded by the annular sacrificial protrusion 32', so that the electrode lead-out structure 3 is disconnected inside the area surrounded by the annular sacrificial protrusion 32'. It should be noted that the arch bridge 31 structure of the electrode lead-out structure is the portion of the conductive material formed on the annular sacrificial protrusion 32'. When forming the electrode lead-out structure 3, a patterned electrode lead-out structure 3 is also included, and when forming the second electrode 23, a patterned second electrode 23 is also included, so that the electrode lead-out structure 3 and the second electrode 23 are at least partially staggered with each other at the periphery of the effective resonance region, so as to avoid high-frequency coupling problems caused by the existence of potential floating, prevent the formation of parasitic capacitance, and help improve the resonator quality factor. When the projections of the electrode lead-out structure 3 and the second electrode 23 on the surface of the piezoelectric layer 22 at the periphery of the effective resonance region are completely staggered, high-frequency coupling problems can be better avoided.

[0058] In this embodiment, the electrode lead-out structure 3 is formed to extend from the periphery of the annular gap to the supporting layer on the periphery of the first cavity formed subsequently. Specifically, the electrode lead-out structure 3 includes an arch bridge 31 and a lap portion connecting the arch bridge 31 and extending to the periphery of the first cavity 121 or the acoustic reflector 51. The periphery of the arch bridge 31 is lapped on the edge of the first electrode 21 in the effective resonance area, and the lap portion surrounds part of the periphery or the entire periphery of the first electrode 21. In other words, part of the periphery of the lap portion extends to the outer edge of the supporting layer 12 on the periphery of the first cavity 121, or the periphery of the lap portion extends to the outer edge of the supporting layer 12 on the periphery of the first cavity 121, so as to be electrically connected to the outside. When the periphery of the lap portion extends to the outer edge of the supporting layer 12 on the periphery of the first cavity 121, the structural strength of the resonator is better. The overlapping portion can be a planar structure without being etched and laid on the first electrode 21; or, the overlapping portion can be etched to form a plurality of overlapping portions with strip structures, and the plurality of strip overlapping portions can be symmetrically distributed on the first electrode 21, thereby improving the structural strength of the resonator.

[0059] It should be noted that in order to reduce the impedance of the first electrode 21, the impedance of the electrode lead-out structure 3 should be lower than the impedance of the first electrode 21. The material of the electrode lead-out structure 3 is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, copper, titanium, tin, and nickel.

[0060] Reference Figure 4 , a support layer 12 is formed on the first electrode 21. In this embodiment, the support layer 12 can be formed on the first electrode 21 by physical vapor deposition or chemical vapor deposition to cover the first electrode 21 and the electrode lead structure 3. The material of the support layer 12 can be any suitable dielectric material, including but not limited to silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc., but the technology of the present invention is not limited thereto.

[0061] Continue to refer to Figure 4 , patterning the support layer 12 to form a first cavity 121 that penetrates the support layer 12. The first cavity 121 exposes at least the arch bridge 31 structure of the electrode lead-out structure 3, so that the effective resonance region is formed above the first cavity 121, thereby facilitating the sound waves located in the effective resonance region and transmitted between the first electrode 21 and the second electrode 23 to be reflected back through the gas interface in the first cavity 121, thereby improving the utilization rate of the sound waves. In this embodiment, the first cavity 121 can be formed by an etching process. The cross-sectional shape of the first cavity 121 can be rectangular, but in other embodiments of the present invention, the cross-sectional shape of the first cavity 121 can also be circular, elliptical, or a polygon other than a rectangle, such as a pentagon, a hexagon, etc.

[0062] Continue to refer to Figure 4, forming a first substrate 11, the first substrate 11 covers the first cavity 121. In this embodiment, the first substrate 11 can be bonded to the support layer 12 by means of a bonding layer. 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 material of the first substrate 11 can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors.

[0063] Reference Figure 5 , remove the carrier substrate, and flip the structure over. The carrier substrate can be removed by grinding or wet etching. Alternatively, an isolation layer can be formed on the carrier substrate before forming the second electrode 23, and then the carrier substrate can be peeled off by removing the isolation layer. The isolation layer can be made of, but is not limited to, at least one of silicon dioxide, silicon nitride, aluminum oxide, aluminum nitride, or thermal expansion tape.

[0064] Continue to refer to Figure 5 , the annular sacrificial protrusion is removed to form an annular gap 32. Specifically, a release hole is formed on the second electrode 23 to penetrate the second electrode 23 and expose the first sacrificial layer material located in the first groove 25 and the annular groove 24, and the annular sacrificial protrusion is removed through the release hole. The method for removing the annular sacrificial protrusion includes: forming a first release hole on the second electrode 23 to expose the annular sacrificial protrusion, and removing the annular sacrificial protrusion through the first release hole. In the process of removing the annular sacrificial protrusion, a corresponding removal method is adopted according to the material of the annular sacrificial protrusion. For example, when the material of the annular sacrificial protrusion is polyimide or photoresist, an ashing method is adopted to remove it. The ashing method is specifically that at a temperature of 250 degrees Celsius, oxygen chemically reacts with the sacrificial layer material through air to generate gaseous substances that volatilize. When the material of the annular sacrificial protrusion is low-temperature silicon dioxide, hydrofluoric acid solvent is used to react with low-temperature silicon dioxide to remove it to form an annular gap 32. The shape of the annular gap 32 is the same as that of the annular sacrificial protrusion.

[0065] In this embodiment, the annular gap 32 is a closed annular structure, and the annular gap 32 is opposite to the annular groove 24. When the annular groove 24 is opposite to the annular gap 32, the projection of the annular groove 24 on the surface of the piezoelectric layer 22 can partially overlap with the projection of the annular gap 32 on the surface of the piezoelectric layer 22, or the projection of the annular groove 24 on the surface of the piezoelectric layer 22 is entirely located within the projection range of the annular gap 32 on the surface of the piezoelectric layer 22. When the projection of the annular groove 24 on the surface of the piezoelectric layer 22 is entirely located within the projection range of the annular gap 32 on the surface of the piezoelectric layer 22, the effect of preventing sound wave leakage is better. In addition, the area enclosed by the annular gap is an effective resonance area, and the first electrode 21, the piezoelectric layer 22, and the second electrode 23 in the effective resonance area overlap with each other on the surface perpendicular to the piezoelectric layer 22.

[0066] In another embodiment, referring to Figure 6-8 The method for forming the first electrode 21, the piezoelectric layer 22, and the second electrode 23 further includes: providing a carrier substrate 4; forming the first electrode 21 on the carrier substrate 4; after removing the carrier substrate 4, sequentially forming the piezoelectric layer 22 and the second electrode 23 on the first electrode 21; and forming the electrode lead structure on the first electrode 21, including: forming the electrode lead structure on the first electrode 21 after forming the first electrode 21 and before forming the supporting layer. Specifically:

[0067] Reference Figure 6 , providing a carrier substrate 4, and forming a first electrode 21 on the carrier substrate 4. It should be noted that an annular groove 24 needs to be etched on the first electrode 21 to facilitate the subsequent formation of the arched bridge structure of the electrode lead structure 3 at a position opposite the annular groove 24. In this embodiment, the annular groove 24 can be formed by etching after forming the first electrode 21 and before forming the electrode lead structure 3. In other embodiments, the annular groove 24 can be formed after removing the carrier substrate 4 and before forming the piezoelectric layer 22.

[0068] Reference Figure 7 The electrode lead-out structure 3 is formed on the first electrode 21; a support layer 12 is formed; the support layer 12 is etched to form a first cavity 121 penetrating the support layer 12; and a first substrate 11 is bonded to the support layer 12, with the first substrate 11 covering the first cavity 121. The specific steps can be referred to those described in Example 1, wherein the annular sacrificial protrusion 32' fills the annular groove and covers the first electrode 21 in the area surrounding the annular groove.

[0069] Reference Figure 8, remove the carrier substrate, flip the structure, and then sequentially deposit the piezoelectric layer 22 and the second electrode 23 on the first electrode 21. In this embodiment, after forming the piezoelectric layer 22, the piezoelectric layer 22 is etched to form a groove penetrating the piezoelectric layer 22 and the first electrode 21. The portion penetrating the first electrode 21 is an annular groove, and the portion penetrating the piezoelectric layer 22 is a first groove. The projections of the annular groove and the first groove on the surface of the piezoelectric layer 22 completely overlap. A sacrificial material is then filled into the groove so that its upper surface is flush with the surface of the piezoelectric layer 22. The second electrode 23 is then formed on the piezoelectric layer 22. In other embodiments, before forming the piezoelectric layer 22, the first electrode 21 is etched to form an annular groove that passes through the first electrode 21; a sacrificial material is filled in the annular groove so that its upper surface is flush with the upper surface of the first electrode 21; the piezoelectric layer 22 is then formed on the first electrode 21, and the piezoelectric layer 22 is etched to form a first groove that passes through the piezoelectric layer 22; a sacrificial material is filled in the first groove so that its upper surface is flush with the upper surface of the piezoelectric layer 22; and the second electrode 23 is then formed on the piezoelectric layer 22, the first groove is opposite to the annular groove, that is, the projection of the first groove on the surface of the piezoelectric layer 22 partially overlaps with the projection of the annular groove on the surface of the piezoelectric layer; or, the projection of the first groove on the surface of the piezoelectric layer 22 is completely within the projection range of the annular groove on the surface of the piezoelectric layer. It should be noted that after forming the second electrode 23, the sacrificial material and the annular sacrificial protrusion are removed. The removal method is similar to that in Example 1 and will not be repeated here.

[0070] In another embodiment, referring to Figure 9-11 The method for forming the first electrode 21, the piezoelectric layer 22, and the second electrode 23 further includes: providing a carrier substrate 4; forming the piezoelectric layer 22 and the first electrode 21 on the carrier substrate 4 in sequence; after removing the carrier substrate 4, forming the second electrode 23 on the piezoelectric layer 22; and forming the electrode lead structure 3 on the first electrode 21, including: forming the electrode lead structure 3 on the first electrode 21 after forming the first electrode 21 and before forming the supporting layer. Specifically:

[0071] Reference Figure 9 A carrier substrate 4 is provided, a piezoelectric layer 22 is formed on the carrier substrate 4, a first electrode 21 is formed on the piezoelectric layer 22, and the first electrode 21 and the piezoelectric layer 22 are etched to form a groove penetrating the first electrode 21 and the piezoelectric layer 22, wherein the portion penetrating the first electrode 21 is an annular groove 24, and the portion penetrating the piezoelectric layer 22 is a first groove 25. In other embodiments, the etching of the annular groove 24 and the first groove 25 can be performed simultaneously or in steps before the subsequent formation of the second electrode 23.

[0072] Reference Figure 10An electrode lead-out structure 3 and a support layer 12 having a first cavity are formed on the first electrode 21; a first substrate 11 is bonded to the support layer 12. The specific steps can be referred to in Example 1 and are not repeated here. The annular sacrificial protrusion 32' forming the arched bridge structure of the electrode lead-out structure 3 fills the annular groove and the first groove, and covers a portion of the first electrode 21 in the area surrounding the annular groove.

[0073] Reference Figure 11 , remove the carrier substrate, flip the structure over, and deposit the second electrode 23 on the piezoelectric layer 22. It should be noted that before forming the second electrode 23, the annular sacrificial protrusion forming the annular gap 31 structure of the electrode lead-out structure 3 can be removed first.

[0074] When the electrode lead-out structure is not formed on the first electrode 21 , the electrode lead-out structure 3 is formed on the second electrode 23 . The formation steps can refer to the above steps and embodiment 1, and are not described again here.

[0075] In other embodiments, when the first electrode 21 is not provided with the electrode lead-out structure 3, it is necessary to form the electrode lead-out structure 3 on the second electrode 23. In the process of forming the electrode lead-out structure 3 on the second electrode, the step of forming the annular groove 24 and the electrode lead-out structure 3 on the first electrode 21 in Example 4 is omitted. After the second electrode 23 is formed, the annular groove and the electrode lead-out structure are formed on the second electrode 23. The formation process can refer to the process of forming the electrode lead-out structure 3 on the first electrode 21, which will not be repeated here. It should be noted that in this process, the first groove 25 can be formed when the annular groove 24 passing through the second electrode 23 is formed, or it can be formed after the piezoelectric layer 22 is formed and before the second electrode 23 is formed. When the first groove is formed after the piezoelectric layer 22 is formed and before the second electrode 23 is formed, it is necessary to fill the first groove 25 with a sacrificial layer material so that its upper surface is kept flat with the surface of the piezoelectric layer 22, and then the second electrode 23 is formed.

[0076] Example 2

[0077] Example 2 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 12 This is a schematic diagram of the structure of a thin film bulk acoustic resonator manufactured according to the method for manufacturing a thin film bulk acoustic resonator according to this embodiment. This embodiment differs from Example 1 in that the piezoelectric layer 22 in Example 1 is formed with a first groove 25. The piezoelectric layer 22 in this embodiment is a complete film layer, eliminating the etching step of the piezoelectric layer 22 in Example 1. The remaining steps refer to Example 1. Specifically, the piezoelectric layer 22 is not etched, remaining a complete film layer, covering the first cavity 121 and extending onto the first substrate 11 outside the first cavity 121, thereby ensuring the structural strength of the resonator and improving the yield rate of the resonator.

[0078] Example 3

[0079] Example 3 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 13-19 FIG2 is a schematic diagram of the structure of a thin film bulk acoustic resonator manufactured according to the manufacturing method of the thin film bulk acoustic resonator of this embodiment. The difference between this embodiment and Example 1 is that in Example 1, one of the first electrode 21 and the second electrode 23 is provided with an electrode lead-out structure 3, while in this embodiment, both the first electrode 21 and the second electrode 24 are provided with an electrode lead-out structure 3. Specifically:

[0080] In this embodiment, referring to Figure 13-15 Specifically, the second electrode 23, the piezoelectric layer 22, and the first electrode 21 are formed on the carrier substrate 4 in sequence; the first electrode 21 is etched to form a groove penetrating the first electrode 21, the piezoelectric layer 22, and the second electrode 23, wherein the portion penetrating the first electrode 21 and the second electrode 23 is a ring groove; the portion penetrating the piezoelectric layer 22 is a first groove 25, refer to Figure 13 Accordingly, when the first sacrificial material is deposited on the first electrode 21 to form an annular sacrificial protrusion, the first sacrificial material fills the groove and covers the first electrode 21 in the peripheral area of ​​the groove, and then forms an electrode lead-out structure 3 covering the annular sacrificial protrusion on the first electrode 21, referring to Figure 14 Then, a support layer 12 is formed on the first electrode 21; the support layer 12 is etched to form a first cavity 121 penetrating the support layer 12; a first substrate 11 is provided to cover the first cavity 121; the carrier substrate 4 is removed, and the above structure is flipped over. Another annular sacrificial protrusion is formed on the second electrode 21, the annular sacrificial protrusion is connected to the above annular sacrificial protrusion and covers a portion of the surface of the second electrode 23, and then an electrode lead structure 3 covering the annular sacrificial protrusion is formed on the second electrode 23, referring to Figure 15 Finally, the sacrificial material is removed. The specific formation process of the above steps and the remaining steps of the thin film bulk acoustic resonator refer to the above embodiment 1 and will not be repeated here.

[0081] It should be noted that forming the electrode lead-out structure 3 on the first electrode 21 also includes patterning the electrode lead-out structure, and forming the electrode lead-out structure 3 on the second electrode 23 also includes patterning the electrode lead-out structure, so that the electrode lead-out structure 3 formed on the first electrode 21 and the electrode lead-out structure 3 formed on the second electrode 23 are at least partially offset from each other at the periphery of the annular gap. That is, at the periphery of the annular gap, the projections of the electrode lead-out structure 3 formed on the first electrode 21 and the electrode lead-out structure 3 formed on the second electrode 23 on the surface of the piezoelectric layer 22 at least partially do not overlap, thereby avoiding high-frequency coupling problems caused by potential floating, preventing the formation of parasitic capacitance, and facilitating improvement of the resonator quality factor. When the electrode lead-out structure 3 formed on the first electrode 21 and the electrode lead-out structure 3 formed on the second electrode 23 are completely offset from each other at the periphery of the annular gap, high-frequency coupling problems can be better avoided.

[0082] Because the area enclosed by the annular gap 32 is the effective resonance region, the arched bridge 31 structure of the electrode lead-out structure 3 formed on the first electrode 21 and the arched bridge 31 structure of the electrode lead-out structure 3 formed on the second electrode 23 are arranged opposite each other. That is, the projections of the arched bridge 31 structure formed on the first electrode 21 and the arched bridge 31 structure formed on the second electrode 23 on the surface of the piezoelectric layer 22 overlap, making the effective resonance region enclosed by the annular gap within the two arched bridges the same area. In addition, the electrode lead-out structure 3 provided on the first electrode 21 and the electrode lead-out structure 3 provided on the second electrode 23 each have a second portion extending outside the effective resonance region to serve as an electrode connection end.

[0083] In another embodiment, referring to Figure 16-17 , perform the steps of the above embodiment 4, and after removing the substrate when carrying and before removing the annular sacrificial protrusion located on the first electrode 21, etch the second electrode 23 to form an annular groove penetrating the second electrode 23, refer to Figure 16 An annular sacrificial protrusion is formed on the second electrode 23, covering the first sacrificial material and part of the second electrode 23, and an electrode lead-out structure 3 covering the annular sacrificial protrusion is formed on the second electrode 23, referring to Figure 17 The first sacrificial material and the annular sacrificial protrusion are removed. The specific formation process corresponding to the above steps and the remaining steps of the thin film bulk acoustic wave resonator refer to Example 1 and are not repeated here.

[0084] Reference Figure 18-19 In another embodiment, the second electrode 23, the piezoelectric layer 22, and the first electrode 21 are sequentially formed on the carrier substrate 4; an electrode lead structure is formed on the first electrode 21, referring to Figure 18A support layer 12 is formed on the first electrode 21; the support layer 12 is etched to form a first cavity 121 penetrating the support layer 12; a first substrate 11 is provided to cover the first cavity 121; the carrier substrate 4 is removed, and the above structure is flipped. A groove penetrating the second electrode 23, the piezoelectric layer 22, and the first electrode 21 is etched on the second electrode 23; a sacrificial material is filled in the groove to cover a portion of the second electrode 23 in the area surrounding the groove; a conductive material is filled to cover the sacrificial material on the surface of the second electrode 23 and a portion of the second electrode 23 to form an electrode lead structure, refer to Figure 19 The sacrificial material is removed. The specific formation process of the above steps is referred to Example 1 and will not be repeated here.

[0085] Example 4

[0086] Example 4 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 20 This is a schematic diagram of the structure of a thin film bulk acoustic resonator manufactured according to the method for manufacturing a thin film bulk acoustic resonator according to this embodiment. This embodiment differs from Example 3 in that the piezoelectric layer 22 in Example 3 is formed with a first groove 25. In this embodiment, the piezoelectric layer 22 is not etched to form the first groove 25, but remains a complete film layer. The etching step of the piezoelectric layer 22 in Example 3 is omitted, and the remaining steps refer to those in Example 3. The beneficial effects of having a complete piezoelectric layer 22 can be seen in Example 2 above and are not further described here.

[0087] In the above-mentioned embodiments 3 and 4, the first electrode 21 and the second electrode 23 are both provided with an electrode lead-out structure 3. The electrode lead-out structure provided on the first electrode 21 and the electrode lead-out structure provided on the second electrode 23 are at least partially staggered with each other at the periphery of the annular gap to avoid high-frequency coupling problems caused by potential floating, prevent the formation of parasitic capacitance, and thereby improve the resonator quality factor. When the electrode lead-out structure provided on the first electrode 21 and the electrode lead-out structure provided on the second electrode 23 are completely staggered at the periphery of the annular gap, high-frequency coupling problems can be better avoided. The structure of the electrode lead-out structure 3 and its relative relationship with the corresponding electrode and the supporting layer can be referred to in embodiment 1 and will not be repeated here.

[0088] Example 5

[0089] Embodiment 5 of the present invention provides a filter comprising at least one FBAR manufactured by the above method. The FBARs are connected to form a filter, ensuring good structural stability. Furthermore, due to the low impedance of the resonator electrodes, the conductivity of the filter can be increased, thereby improving filtering accuracy.

[0090] It should be noted that the various embodiments in this specification are described in a related manner. Similar portions between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, since the structural embodiments are generally similar to the method embodiments, their description is relatively simple. For related portions, refer to the description of the method embodiments.

[0091] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians 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 method for manufacturing a thin film bulk acoustic resonator, characterized in that: include: forming a first electrode, a piezoelectric layer, and a second electrode, wherein the piezoelectric layer is located between the first electrode and the second electrode; forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode; An electrode lead-out structure having an arched bridge is formed on the electrode having the annular groove, comprising: forming an annular sacrificial protrusion; forming an electrode lead-out structure covering the annular sacrificial protrusion and having its edge overlapped on the edge of the electrode in the effective resonance region; forming a supporting layer on the first electrode; Patterning the support layer to form a first cavity penetrating the support layer, wherein the arched bridge of the electrode lead-out structure is located within the first cavity; providing a first substrate, wherein the first substrate covers the first cavity; The annular sacrificial protrusion is removed to form an annular gap, and the annular gap is opposite to the annular groove.

2. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The method for forming the first electrode, the piezoelectric layer and the second electrode comprises: providing a carrier substrate; forming the second electrode, the piezoelectric layer and the first electrode in sequence on the carrier substrate; After the first substrate covers the first cavity on the support layer, removing the carrier substrate; At least one of the first electrode and the second electrode forms the electrode lead-out structure; Forming an electrode lead-out structure on the first electrode includes: forming an electrode lead-out structure on the first electrode after forming the first electrode and before forming the support layer; Forming an electrode lead-out structure on the second electrode includes: removing the carrier substrate and then forming the electrode lead-out structure on the second electrode; or providing a carrier substrate; forming the first electrode on the carrier substrate; After removing the carrier substrate, forming a piezoelectric layer and a second electrode in sequence on the first electrode; At least one of the first electrode and the second electrode forms the electrode lead-out structure; Forming an electrode lead-out structure on the first electrode includes: forming an electrode lead-out structure on the first electrode after forming the first electrode and before forming the support layer; Forming an electrode lead-out structure on the second electrode includes: removing the carrier substrate and then forming the electrode lead-out structure on the second electrode; or providing a carrier substrate; forming a piezoelectric layer and a first electrode in sequence on the carrier substrate; After removing the carrier substrate, forming the second electrode on the piezoelectric layer; At least one of the first electrode and the second electrode forms the electrode lead-out structure; Forming an electrode lead-out structure on the first electrode includes: forming an electrode lead-out structure on the first electrode after forming the first electrode and before forming the support layer; Forming an electrode lead-out structure on the second electrode includes: after removing the carrier substrate, forming the electrode lead-out structure on the second electrode.

3. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: After forming the corresponding electrodes, etching the corresponding electrodes to form an annular groove penetrating the corresponding electrodes; Before or after forming the annular groove on the corresponding electrode, an electrode lead-out structure is formed on the corresponding electrode.

4. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The method of forming an electrode lead-out structure on the corresponding electrode, which covers the annular sacrificial protrusion and has an edge overlapping the edge of the effective resonance region electrode, includes: depositing a conductive material on the corresponding electrode to form an electrode lead-out structure, wherein the electrode lead-out structure covers the annular sacrificial protrusion provided on the corresponding electrode; or depositing a conductive material on the corresponding electrode, wherein the conductive material covers the corresponding electrode and the annular sacrificial protrusion formed on the corresponding electrode; The conductive material is etched to remove a portion of the conductive material located in the area surrounded by the annular sacrificial protrusion to form an electrode lead structure.

5. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The electrode lead-out structure extends from the periphery of the annular gap to the support layer at the periphery of the first cavity.

6. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The periphery of the first electrode and / or the second electrode extends onto the support layer at the periphery of the first cavity.

7. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: One of the first electrode and the second electrode is provided with an electrode lead-out structure, and the electrode lead-out structure and the corresponding electrode without the electrode lead-out structure respectively have a first portion extending outside the effective resonance region, and the first portion serves as an electrode connection end.

8. The method for manufacturing a thin film bulk acoustic resonator according to claim 7, wherein: When forming the electrode lead-out structure, the electrode lead-out structure is also patterned, and when forming a corresponding electrode without the electrode lead-out structure, the corresponding electrode is also patterned, so that the electrode lead-out structure and the corresponding electrode without the electrode lead-out structure are at least partially staggered with each other on the periphery of the annular gap.

9. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The first electrode and the second electrode both form electrode lead-out structures. The electrode lead-out structure provided on the first electrode and the electrode lead-out structure provided on the second electrode respectively have a second portion extending outside the effective resonance region, and the second portion serves as an electrode connection end.

10. The method for manufacturing a thin film bulk acoustic resonator according to claim 9, wherein: When forming the electrode lead-out structure, the method further includes patterning the electrode lead-out structure so that the electrode lead-out structure formed on the first electrode and the electrode lead-out structure formed on the second electrode are at least partially staggered with each other at the periphery of the annular gap; The arched bridge structure of the electrode lead-out structure formed on the first electrode is arranged opposite to the arched bridge structure of the electrode lead-out structure formed on the second electrode.

11. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The impedance of the electrode lead-out structure is lower than the impedance of the corresponding electrode.

12. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The material of the electrode lead-out structure is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, copper, titanium, tin, and nickel.

13. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The annular space is a closed annular space.

14. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The formed piezoelectric layer covers the first cavity and extends to the periphery of the first cavity; or, after the piezoelectric layer is formed, the piezoelectric layer is etched to form a first groove penetrating the piezoelectric layer, and the first groove is opposite to the annular groove.

15. The method for manufacturing a thin film bulk acoustic resonator according to claim 14, wherein: The first groove is a closed ring, and the piezoelectric layer inside the annular gap is isolated from the piezoelectric layer outside the annular gap; or, the first groove is a discontinuous ring, and the piezoelectric layer inside the annular gap is isolated from the piezoelectric layer outside the annular gap by the discontinuity.

16. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The material of the support layer includes: silicon dioxide, silicon nitride, aluminum oxide or aluminum nitride, silicon oxynitride, and silicon carbonitride.

17. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The forming of the first substrate on the supporting layer includes: forming a bonding layer on the supporting layer or the first substrate, and bonding the first substrate and the supporting layer through the bonding layer to cover the first cavity.

18. The method for manufacturing a thin film bulk acoustic resonator according to claim 17, wherein: The material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.

19. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The material of the annular sacrificial protrusion includes phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, amorphous carbon, polyimide or photoresist.

20. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The material of the first electrode or the second electrode includes: one or more of molybdenum, aluminum, copper, tungsten, tantalum, platinum, ruthenium, rhodium, iridium, chromium, titanium, gold, osmium, rhenium or palladium.

21. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: The material of the piezoelectric layer includes: aluminum nitride, zinc oxide, lead zirconate titanate, lithium niobate, quartz, potassium niobate or lithium tantalate.

22. A filter, characterized in that: The invention comprises at least one thin film bulk acoustic resonator formed by the method for manufacturing a thin film bulk acoustic resonator according to any one of claims 1 to 21.

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