Thin film bulk acoustic resonator, manufacturing method thereof, and filter

Abstract

The present invention relates to a thin film bulk acoustic wave resonator, a manufacturing method thereof, and a filter, wherein the thin film bulk acoustic wave resonator comprises: a piezoelectric stack structure, the piezoelectric stack structure comprising a first electrode, a piezoelectric layer, and a second electrode stacked sequentially from bottom to top, at least one of the first electrode and the second electrode having an annular groove extending through the corresponding electrode; an electrode lead-out structure is provided on the corresponding electrode having the annular groove, the electrode lead-out structure covering at least a portion of the annular groove and extending to an ineffective resonance region, the electrode lead-out structure comprising an annular arched bridge protruding away from the piezoelectric layer, the inner surface of the arched bridge forming an annular gap, the annular gap being opposite to the annular groove. The present invention defines the boundary of the effective region by the region where the annular gap of the electrode lead-out structure is located, and the annular groove is used to allow the end of the corresponding electrode at the boundary of the effective region to contact the gas in the gap, thereby achieving the effect of eliminating boundary noise of the electrode in the effective 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 thin film bulk acoustic resonator, a manufacturing method thereof, 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 the currently manufactured cavity-type thin film bulk acoustic resonators cannot be further improved, and therefore cannot meet the requirements of high-performance RF systems. Summary of the Invention

[0005] An object of the present invention is to provide a thin film bulk acoustic wave resonator, a manufacturing method thereof, 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 thin film bulk acoustic resonator, comprising:

[0007] A piezoelectric stack structure, the piezoelectric stack structure comprising a first electrode, a piezoelectric layer, and a second electrode stacked sequentially from bottom to top, wherein at least one of the first electrode and the second electrode has an annular groove running through the corresponding electrode;

[0008] An electrode lead-out structure is provided on the corresponding electrode provided with an annular groove. The electrode lead-out structure covers at least a portion of the annular groove and extends to the invalid resonance zone. The electrode lead-out structure includes an annular arch bridge protruding away from the piezoelectric layer. The inner surface of the arch bridge forms an annular gap, which is opposite to the annular groove.

[0009] The present invention also provides a method for manufacturing a thin film bulk acoustic resonator, comprising:

[0010] 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;

[0011] forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode;

[0012] 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;

[0013] forming a support layer having a sacrificial layer on the first electrode;

[0014] The sacrificial layer is removed to form a first cavity; the annular sacrificial protrusion is removed to form an annular gap, and the annular gap is opposite to the annular groove.

[0015] The present invention also provides a method for manufacturing a thin film bulk acoustic resonator, comprising:

[0016] 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;

[0017] forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode;

[0018] 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;

[0019] forming a support layer having an acoustic reflection mirror on the first electrode;

[0020] An annular gap is formed by removing the annular sacrificial protrusion, and the annular gap is opposite to the annular groove.

[0021] The present invention also provides a filter comprising at least one thin film bulk acoustic resonator as described above.

[0022] The beneficial effects of the thin film bulk acoustic wave resonator of the present invention are: an electrode lead-out structure with an arch bridge structure is provided on the first electrode and / or the second electrode, the arch bridge is formed into a ring, and an annular gap is formed between the arch bridge and the surface of the plane where the corresponding electrode is located. The area where the arch bridge is located defines the boundary of the effective resonance zone, and an annular groove is provided on the corresponding electrode to disconnect the corresponding electrode, and then the disconnected electrodes are connected through the electrode lead-out structure. In addition, the annular groove can also enable the end of the first electrode and / or the second electrode at the boundary of the effective resonance zone to contact the gas in the annular gap, thereby achieving the effect of eliminating the boundary noise of the electrode in the effective resonance zone, thereby improving the Q value of the resonator.

[0023] 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.

[0024] 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.

[0025] Furthermore, the first electrode and / or the second electrode extends from the effective resonance region to the first cavity or the first substrate outside the acoustic reflector, 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 cavity or the first substrate outside the acoustic reflector to improve the structural strength of the resonator.

[0026] Furthermore, the piezoelectric layer is a complete film layer, which can ensure the structural strength of the resonator and improve the yield of the resonator.

[0027] 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.

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

[0029] An electrode lead-out structure with an arched bridge structure is formed by forming an annular sacrificial protrusion on the corresponding electrode, and after removing the annular sacrificial protrusion, an annular gap is formed to define the range of the effective resonance zone, and then an annular groove penetrating the corresponding electrode is formed by etching the corresponding electrode. This not only simplifies the formation process of the electrode lead-out structure, but also separates the electrodes inside and outside the annular groove, and electrically connects the disconnected electrodes through the electrode lead-out structure, thereby reducing the impedance of the electrode and exposing 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 zone.

[0030] Furthermore, by forming the first cavity using a sacrificial layer, manufacturing costs can be reduced, and support can be provided in the subsequent process of forming the support layer to prevent the first electrode, the piezoelectric stack and the second electrode from being deformed by uneven force. The piezoelectric stack structure can also be supported in the subsequent reverse process to ensure the flatness of the piezoelectric stack structure.

[0031] 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.

[0032] The filter of the present invention has the following beneficial effects:

[0033] 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

[0034] 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.

[0035] Figure 1 FIG2 shows a schematic structural diagram of a thin film bulk acoustic resonator according to Example 1 of the present invention;

[0036] Figure 2 FIG2 shows a schematic structural diagram of a thin film bulk acoustic resonator according to Example 2 of the present invention;

[0037] Figure 3 FIG2 shows a schematic structural diagram of a thin film bulk acoustic resonator according to Example 3 of the present invention;

[0038] Figures 4 to 7Schematic diagram showing the structures corresponding to different steps of the method for manufacturing a thin film bulk acoustic resonator according to embodiment 4 of the present invention;

[0039] Figures 8 to 10 A schematic structural diagram showing different steps of another method for manufacturing a thin film bulk acoustic resonator formed in Example 4 of the present invention is shown;

[0040] Figures 11 to 13 A schematic structural diagram showing different steps of another method for manufacturing a thin film bulk acoustic resonator formed in Example 4 of the present invention is shown;

[0041] Figure 14 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 5;

[0042] Figure 15-21 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 6;

[0043] Figure 22 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 7;

[0044] Figure 23 Schematic diagram of the structure of a thin film bulk acoustic wave resonator manufactured according to the method for manufacturing a thin film bulk acoustic wave resonator in Example 8.

[0045] Description of reference numerals:

[0046] 1. First substrate; 11. Base; 12. Support layer; 121. First cavity; 121', sacrificial layer; 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

[0047] 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.

[0048] 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. Example 1

[0049] Embodiment 1 provides a thin film bulk acoustic resonator. Figure 1 This is a schematic diagram of the cross-sectional structure of a thin film bulk acoustic resonator provided in Example 1 of the present invention, please refer to Figure 1 , the thin film bulk acoustic resonator comprises:

[0050] The piezoelectric stack structure 2 includes a first electrode 21, a piezoelectric layer 22, and a second electrode 23 stacked in sequence from bottom to top, wherein at least one of the first electrode 21 and the second electrode 23 has an annular groove 24 extending through the corresponding electrode;

[0051] An electrode lead-out structure 3 is provided on the corresponding electrode provided with an annular groove 24. The electrode lead-out structure 3 covers at least part of the annular groove 24 and extends to the invalid resonance zone. The electrode lead-out structure 3 includes an annular arch bridge 31 protruding in a direction away from the piezoelectric layer 22. The inner surface of the arch bridge 31 forms an annular gap 32, and the annular gap 32 is opposite to the annular groove 24. It should be noted that the area surrounded by the annular gap 32 is the effective resonance zone, and the area outside the effective resonance zone is the invalid resonance zone. The boundary of the effective resonance zone is defined by the annular gap 32 to effectively prevent shear wave leakage. It should be noted that the above-mentioned corresponding electrode is an electrode provided with an annular groove 24, that is, when the first electrode 21 is provided with an annular groove 24, the first electrode 21 is an electrode corresponding to the annular groove 24, and the first electrode 21 corresponds to the electrode lead-out structure 3 provided thereon; when the second electrode 23 is provided with an annular groove 24, the second electrode 23 is an electrode corresponding to the annular groove 24, and the second electrode 23 corresponds to the electrode lead-out structure 3 provided thereon. The structure of the thin film bulk acoustic resonator is specifically described below by taking the example of providing the annular groove 24 on the first electrode 21 and forming the electrode lead structure 3 on the first electrode 21 .

[0052] The piezoelectric stack structure 2 is formed on a first substrate 1 having a first cavity 121. The piezoelectric stack structure 2 includes a first electrode 21, a piezoelectric layer 22, and a second electrode 23 stacked in sequence. The materials of the first electrode 21 and the second electrode 23 can be any suitable conductive material or semiconductor material well known in the art. The conductive material can be a metal material with conductive properties, for example, made of one of the 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. The semiconductor material is, 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).

[0053] The four sides of the first electrode 21 and / or the second electrode 23 extend to the first substrate 1 outside the first cavity 121 to improve the structural strength of the resonator. When the four sides of the first electrode 21 and the second electrode 23 both extend to the first substrate 1 outside the first cavity 121, the structural strength of the resonator is better. It should be noted that the four sides of the first electrode 21 are the outer edges of its overall structure, and the four sides of the second electrode 23 are the outer edges of its overall structure. In this embodiment, all four sides of the first electrode 21 and / or the second electrode 23 extend to the first substrate 1 outside the first cavity 121. In other embodiments, part of the four sides of the first electrode 21 and / or the second electrode 23 extend to the first substrate 1 outside the first cavity 121. At this time, in order to ensure the structural strength of the resonator, the electrodes that partially extend to the first substrate 1 outside the first cavity 121 are symmetrically distributed to ensure support strength.

[0054] In this embodiment, the impedance of the electrode lead-out structure 3 is lower than that of the first electrode 21, and the annular groove 24 is a closed annular groove. The annular groove 24 completely isolates the first electrode 21 at the annular groove 24. The disconnected first electrode 21 is then electrically connected via the electrode lead-out structure 3, which has a lower impedance than the first electrode 21, thereby reducing the impedance of the first electrode 21. The electrode lead-out structure 3 can be made of a metal material, including one or more of gold, silver, tungsten, platinum, aluminum, copper, titanium, tin, and nickel.

[0055] Specifically, the electrode lead-out structure 3 and the second electrode 23 each have a first portion extending outside the effective resonant region, with the first portion serving as an electrode connection end for electrical connection to the outside. Specifically, the periphery of the electrode lead-out structure 3 and the second electrode 23 extends to the first substrate 1 outside the first cavity 121. In this case, the periphery of the first electrode 21 may or may not extend to the first substrate 1 outside the first cavity 121. When the periphery of the first electrode 21 can extend to the first substrate 1 outside the first cavity 121, the first electrode 21 and the electrode lead-out structure 3 together form a support to enhance the structural strength of the resonator.

[0056] Furthermore, outside the annular gap 32, the projections of the electrode lead-out structure 3 and the corresponding electrodes without the electrode lead-out structure 3 on the surface of the piezoelectric layer 22 are at least partially offset. That is, the projections of the electrode lead-out structure 3 and the second electrode 23 on the surface of the piezoelectric layer 22 outside the effective resonance region at least partially do not overlap. This prevents high-frequency coupling caused by potential floating, prevents the formation of parasitic capacitance, and thereby improves 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 outside the annular gap 32 are completely offset, high-frequency coupling can be effectively avoided.

[0057] In this embodiment, the annular gap 32 is positioned opposite the annular groove 24, so that the edge of the first electrode 21 at the boundary of the effective resonance region is exposed to the annular gap 32. This reduces the acoustic wave energy leaking from the end of the first electrode 21, thereby improving the quality factor of the resonator. It should be noted that the relative position of the annular gap 32 and the annular groove 24 can be referred to the relative position of the annular groove 24 and the first groove 25 described above, and will not be repeated here.

[0058] The annular gap 32 is a closed ring, so as to define the boundary of the effective resonance zone, thereby effectively eliminating the noise at the boundary of the effective resonance zone. It should be noted that the arch bridge 31 surrounds the entire periphery of the first electrode 21, so that the annular gap 32 forms a closed ring. The electrode lead-out structure 3 also includes a lap portion connected to the arch bridge 31 and extending to the periphery of the first cavity 121. The lap portion surrounds part of the periphery or the entire periphery of the corresponding electrode. Part of the lap portion extends to the outer edge of the first substrate 1 outside the first cavity 121, or the lap portion extends to the outer edge of the first substrate 1 outside the first cavity 121, so as to facilitate electrical connection with the outside. In addition, the lap portion can be a planar structure laid on the corresponding electrode; or the lap portion can be a plurality of strip structures, and the plurality of lap portions are symmetrically distributed on the corresponding electrode to improve the structural strength of the resonator.

[0059] In this embodiment, the effective resonance region is an irregular polygon, and any two sides of the polygon are not parallel. In other embodiments, the effective resonance region may also be a circle or an ellipse or an irregular shape composed of arcs and straight lines.

[0060] A first groove 25 is provided in the piezoelectric layer 22. The first groove 25 passes through the piezoelectric layer 22, and the first groove 25 is opposite to the annular groove 24, so that the first groove 25, the annular groove 24 and the annular gap 32 are connected, so that the end face of the piezoelectric layer 22 and the gas in the annular gap 32 form a reflection interface, thereby effectively suppressing the leakage of sound waves in the piezoelectric layer 22, and avoiding parasitic resonance, thereby improving the quality factor of the resonator. It should be noted that the relative relationship between the first groove 25 and the annular groove 24 can refer to the relative relationship between the annular groove 24 and the annular gap 32, and will not be repeated here. When the projections of the first groove 25 on the surface of the piezoelectric layer 22 are all located within the projection range of the annular groove 24 on the surface of the piezoelectric layer 22 and the projection range of the annular gap 32 on the surface of the piezoelectric layer 22, the effect of suppressing sound waves is better. Alternatively, the first groove 25 may be a closed ring, isolating the piezoelectric layer 22 within the annular gap 32 from the piezoelectric layer 22 outside the annular gap 32. Alternatively, the first groove 25 may be a discontinuous ring, isolating the piezoelectric layer 22 within the annular gap 32 from the piezoelectric layer outside the annular gap 32 via the discontinuity. When the first groove 25 is a closed ring, the acoustic wave leakage suppression effect is better.

[0061] In this embodiment, the first groove 25 is a closed ring shape, isolating the piezoelectric layer 22 within the effective resonance region from the piezoelectric layer 22 outside the effective resonance region. Alternatively, the first groove 25 is a discontinuous ring shape, isolating the piezoelectric layer 22 within the effective resonance region from the piezoelectric layer 22 outside the effective resonance region at the discontinuity and connecting them at the non-discontinuity. It will be appreciated that when the first groove 25 is a closed ring shape and penetrates the piezoelectric layer 22, the effect of suppressing acoustic wave leakage is better.

[0062] In this embodiment, a piezoelectric stack structure 2 is provided on a first substrate 1 having a first cavity 121, and the piezoelectric stack structure 2 covers the first cavity 121. Specifically, the first substrate includes a base 11 and a support layer 12, the support layer 12 and the piezoelectric stack structure 2 are sequentially stacked on the base 11, and the first cavity 121 is provided in the support layer 12. It should be noted that the support layer 12 can be bonded to the base 11 by a bonding layer or deposition. The material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride 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. The deposition method can be chemical vapor deposition or physical vapor deposition. The material of the 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. 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.

[0063] In this embodiment, the first cavity 121 partially penetrates the supporting layer 12, that is, the first cavity 121 extends to part of the thickness of the supporting layer 12, so that the first cavity 121 exposes the supporting layer 12. In other embodiments, the first cavity 121 completely penetrates the supporting layer 12, so that the first cavity 121 exposes the substrate 11. The first cavity 121 can be formed by a sacrificial layer process or by etching. In an alternative embodiment, when the bottom of the first cavity 121 exposes the supporting layer 12, it is formed by a sacrificial layer process. The specific formation method will be described in the method embodiment below. When the first cavity 121 penetrates the supporting layer 12, the first cavity 121 can be formed by etching the supporting layer 12 or forming a sacrificial layer. In this embodiment, 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 or hexagon.

[0064] In other embodiments, the first substrate 1 includes a semiconductor substrate, the material of which can refer to the material of the base 11 and will not be repeated here. The first cavity 121 is formed in the first substrate 1, and the first cavity 121 that does not penetrate the first substrate 1 is formed by etching the surface of the first substrate 1 adjacent to the first electrode 21, and the first substrate 1 forming the first cavity 121 is bonded to the first electrode 21.

[0065] In other embodiments, a piezoelectric stacked structure 2 is provided on a second substrate having an acoustic reflector. The acoustic reflector is, for example, a Bragg reflector structure, which is common knowledge in the art and will not be described in detail here.

[0066] In other embodiments, only an annular groove is provided on the second electrode 23 , and an electrode lead-out structure is formed on the second electrode 23 . The structure thereof specifically refers to the structure of the annular groove 24 and the electrode lead-out structure 3 provided on the first electrode 21 above, and will not be repeated here. Example 2

[0067] Embodiment 2 provides a thin film bulk acoustic resonator. Figure 2 This is a schematic diagram of the cross-sectional structure of the thin film bulk acoustic wave resonator of Example 2 of the present invention. The difference between this embodiment and Example 1 is that the piezoelectric layer 22 in Example 1 is provided with a first groove 25, while the piezoelectric layer 22 in Example 2 is a complete film layer. Specifically, the piezoelectric layer 22 is a complete film layer, covering the first cavity 121 and extending to the first substrate 1 outside the first cavity 121. The piezoelectric layer 22 is complete and does not need to be etched, which can ensure the structural strength of the resonator and improve the yield of the resonator. The other structural features of the thin film bulk acoustic wave resonator of this embodiment are the same as those of Example 1 and will not be repeated here. Example 3

[0068] Embodiment 3 provides a thin film bulk acoustic resonator. Figure 3 This is a schematic cross-sectional view of the thin film bulk acoustic resonator according to Example 3 of the present invention. The difference between this embodiment and Example 1 is that the electrode lead-out structure 3 in Example 1 is only provided on the first electrode 21 or the second electrode 23, while the electrode lead-out structure in Example 3 is provided on the first electrode 21 and the second electrode 23. Specifically:

[0069] In this embodiment, both the first electrode 21 and the second electrode 23 are 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 each have a second portion extending outside the effective resonance region, with the second portion serving as an electrode connection end. 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 are at least partially staggered relative to each other at the periphery of the annular gap 32. That is, at the periphery of the annular gap 32, the projections of 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 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 an improvement in the resonator quality factor.

[0070] In order to ensure that the resonator has good structural strength, the electrode lead-out structure 3 arranged on the first electrode 21 and the electrode lead-out structure 3 arranged on the second electrode 23 extend from the effective resonance area to the first substrate 1 outside the first cavity 121, and the first electrode 21 and the second electrode 23 are all extended to the first substrate 1 outside the first cavity 121, so that the first electrode 21 and the electrode lead-out structure arranged thereon, the second electrode 23 and the electrode lead-out structure arranged thereon jointly form a support, thereby improving the structural strength of the resonator. It should be noted that since the annular gap 32 encloses an effective resonance region, in order to avoid the effective resonance region enclosed by the annular gap 32 formed by the arched bridge structure 31 disposed on the first electrode 21 being offset from the effective resonance region enclosed by the annular gap 32 formed by the arched bridge structure 31 disposed on the second electrode 23, it is necessary to arrange the arched bridge structure 31 disposed on the first electrode 21 opposite to the arched bridge structure disposed on the second electrode 23, that is, the projections of the arched bridge structure 31 disposed on the second electrode 23 and the arched bridge structure 31 disposed on the first electrode 21 on the surface of the piezoelectric layer 22 completely overlap. In addition, since the overlapping portion on the first substrate 1 extending to the periphery of the first cavity 121 plays a connecting and supporting role, the overlapping portions respectively disposed on the two electrodes may overlap or not overlap in projection on the surface of the piezoelectric layer 22. The structure of the overlapping portion can refer to Example 1 and will not be described in detail here.

[0071] In this embodiment, a first groove 25 is provided in the piezoelectric layer 22, extending through the piezoelectric layer 22. In another embodiment, the piezoelectric layer 22 may be formed without etching the first groove 25, thereby providing a complete film layer. The advantages of providing the first groove 25 are discussed in Example 1, while the advantages of not providing the first groove 25 are discussed in Example 2, which will not be further described here. The other structural features of the FBAR of this embodiment are the same as those of Example 1 and will not be further described here. Example 4

[0072] Embodiment 4 provides a method for manufacturing a thin film bulk acoustic wave resonator. The method for manufacturing the thin film bulk acoustic wave resonator includes:

[0073] 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;

[0074] S02: forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode;

[0075] 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;

[0076] S04: forming a support layer having a sacrificial layer on the first electrode;

[0077] S05: removing the sacrificial layer to form a first cavity; removing the annular sacrificial protrusion to form an annular gap, wherein the annular gap is opposite to the annular groove.

[0078] Steps S0N do not represent a sequential order.

[0079] An electrode lead-out structure is provided on one of the first electrode 21 and the second electrode 23. For example, the electrode lead-out structure is provided on the first electrode 21. Figures 4 to 7 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 4 to 7 The method for manufacturing the thin film bulk acoustic resonator provided by this embodiment is described in detail.

[0080] refer to Figures 4 to 7 In this embodiment, the method for forming the first electrode 21, the piezoelectric layer 22, and the second electrode 23 includes: providing a carrier substrate 4; sequentially forming the second electrode 23, the piezoelectric layer 22, and the first electrode 21 on the carrier substrate 4; after forming the support layer 12 on the first electrode 21, removing the carrier substrate 4. Specifically, after forming the first electrode, an electrode lead structure is formed on the first electrode. Specifically,

[0081] refer to Figure 4 , provide 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. The second electrode 23, the piezoelectric layer 22, and the first electrode 21 are formed on the carrier substrate 4 in sequence, wherein the first electrode 21 and the second electrode 23 can be formed by physical vapor deposition and etching. The materials of the first electrode 21 and the second electrode 23 refer to Example 1. In addition, 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, and its beneficial effects refer to Example 1. The piezoelectric layer 22 can be deposited and formed by any suitable method well known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition, and the materials of the piezoelectric layer 22 refer to Example 1. By forming the piezoelectric layer 22 on the flat second electrode 23, the upper and lower surfaces of the piezoelectric layer 22 are both flat, thereby ensuring that the piezoelectric layer 22 has a good lattice orientation, improving the piezoelectric properties of the piezoelectric layer 22, and thus improving the overall performance of the resonator.

[0082] Continue to refer to Figure 4Before forming the annular sacrificial protrusion, the first electrode 21 is etched to form an annular groove 24. In this embodiment, during the process of etching the annular groove 24, the piezoelectric layer 22 can also be etched to form a first groove 25 that penetrates the piezoelectric layer 22. The beneficial effects of forming the first groove 25 in the piezoelectric layer 22 are described in detail in the above-mentioned embodiment 1 and will not be further described here. It should be noted that the area enclosed by the subsequently formed annular sacrificial protrusion is the effective resonance region.

[0083] In this embodiment, the first groove 25 is a closed ring, and the piezoelectric layer 22 in the effective resonance region is isolated from the piezoelectric layer 22 outside the effective resonance region; alternatively, the first groove 25 is a discontinuous ring, and the piezoelectric layer 22 in the effective resonance region is isolated from the piezoelectric layer 22 outside the effective resonance region by the discontinuity, and the piezoelectric layer 22 in the effective resonance region is connected to the piezoelectric layer 22 outside the effective resonance region by a non-discontinuity. When the electrode lead structure 3 is not formed on the first electrode 21, this step can be omitted.

[0084] Reference Figure 5 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 material may include phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, amorphous carbon, polyimide, or photoresist. The first sacrificial 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 effective resonant region of the resonator.

[0085] Continue to refer to Figure 5 , forming an electrode lead-out structure 3 on the first electrode 21, covering the annular sacrificial protrusion 32' and overlapping the edge of the effective resonance region electrode, specifically including: depositing a conductive material on the first electrode 21 to form an electrode lead-out structure 3, the electrode lead-out structure 3 covering the first electrode 21 and the annular sacrificial protrusion 32' provided on the first electrode 21, and extending to the support layer 12 outside the first cavity; or, depositing a conductive material on the first electrode 21 to cover the annular sacrificial protrusion 32' provided on the first electrode 21; etching the conductive material to remove the conductive material in the area surrounded by the annular sacrificial protrusion 32', forming an electrode lead-out structure 3, the formed electrode lead-out structure 3 covers the portion of the first electrode 21 located around the annular groove and extends to the support layer 12 outside the first cavity. In the actual manufacturing process, the electrode lead-out structure 3 only needs to be used to connect the first electrode 21 disconnected by the annular groove and extend to the support layer outside the first cavity formed subsequently to be electrically connected to the outside. The structure of the formed electrode lead-out structure 3 and its beneficial effects are referred to in Example 1 and will not be repeated here.

[0086] When forming the electrode lead-out structure 3 on the first electrode 21, the electrode lead-out structure is patterned so that the electrode lead-out structure 3 and the subsequently formed second electrode are at least partially offset from each other at the periphery of the effective resonance region. The specific structure and beneficial effects are as described in Example 1 and are not described in detail here. In addition, the structure of the formed electrode lead-out structure 3 and its positional relationship with the first electrode 21 are also as described in Example 1 and are not described in detail here.

[0087] In subsequent processes, the annular sacrificial protrusion 32' will be removed, forming an annular gap. The annular gap is a closed annular structure, and the annular gap is opposite the annular groove. The beneficial effects of forming the electrode lead structure 3 with the arched bridge 31 and the annular gap opposite the annular groove are described in Example 1. If the electrode lead structure 3 is not formed on the first electrode 21, this step can be omitted.

[0088] Reference Figure 6 , a supporting layer having a sacrificial layer 121' is formed on the first electrode 21. Specifically, a sacrificial layer 121' is formed on the first electrode 21, covering part of the electrode lead structure 3 and its corresponding part of the first electrode 21; a supporting layer 12 is formed, covering the sacrificial layer 121' and the periphery of the sacrificial layer 121'; and the sacrificial layer 121' is removed to form a first cavity. It should be noted that the sacrificial layer 121' at least covers the arch bridge 31 structure of the electrode lead structure 3, so that the effective resonance area is formed above the first cavity, thereby facilitating the reflection of longitudinal waves in the effective resonance area and improving the utilization rate of sound waves. The supporting layer 12 covers the sacrificial layer 121' and the electrode lead structure 3 and the first electrode 21 located on the periphery of the sacrificial layer 121'. The selection of the material of the sacrificial layer 121' refers to the first sacrificial material mentioned above and will not be repeated here. It should be noted that when the electrode lead structure 3 is not formed on the first electrode 21, the sacrificial layer 121' only covers part of the first electrode 21.

[0089] The method for removing the sacrificial layer 121' includes: forming a first release hole on the support layer 12 to expose the sacrificial layer 121', and removing the sacrificial layer 121' through the first release hole. In the process of removing the sacrificial layer 121', a corresponding removal method is adopted according to the material of the sacrificial layer 121'. For example, when the sacrificial layer 121' is made of polyimide or photoresist, it is removed by ashing. 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 evaporate. When the sacrificial layer 121' is made of low-temperature silicon dioxide, hydrofluoric acid solvent is used to react with low-temperature silicon dioxide to remove it to form a first cavity 121. The shape of the first cavity 121 is the same as that of the sacrificial layer 121'. It should be noted that the sacrificial layer 121' can also be removed together with the subsequent removal of the annular sacrificial protrusion 32'.

[0090] In addition, after the support layer 12 is formed, the substrate 11 may be formed on the support layer 12 . The bonding method of the support layer 12 and the substrate 11 may refer to that in Example 1.

[0091] Reference Figure 7 , remove the carrier substrate and flip the structure over. The carrier substrate can be removed by a grinding process or a wet etching process, or an isolation layer can be formed on the carrier substrate before forming the second electrode 23, and the carrier substrate can be peeled off by removing the isolation layer. The material of the isolation layer includes but is not limited to at least one of silicon dioxide, silicon nitride, aluminum oxide, aluminum nitride, or thermal expansion tape. After removing the carrier substrate, the second electrode 23 is patterned so that the second electrode 23 and the electrode lead structure 3 formed on the first electrode 21 are at least partially offset from each other at the periphery of the annular gap 32.

[0092] Continue to refer to Figure 7 The annular sacrificial protrusion 32' is removed to form an annular gap 32, which is opposite the annular groove 24. Specifically, a second release hole is formed on the second electrode 23, penetrating the second electrode 23 to expose the first sacrificial material within the first groove 25 and the annular groove 24. The annular sacrificial protrusion is removed through the second release hole. It should be noted that the method for removing the annular sacrificial protrusion can be referred to the method for removing the sacrificial layer and will not be further described here.

[0093] 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.

[0094] In another embodiment, referring to Figure 8-10The 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 forming the support layer 12 on the first electrode 21, removing the carrier substrate 4; then sequentially forming the piezoelectric layer 22 and the second electrode 23 on the first electrode 21; forming the electrode lead-out structure 3 on the first electrode 21; forming the electrode lead-out structure 3 on the first electrode 21 includes: forming the electrode lead-out structure 3 on the first electrode 21 after forming the first electrode 21 and before forming the support layer 12. Specifically:

[0095] Reference Figure 8 A carrier substrate 4 is provided, and a first electrode 21 is formed on the carrier substrate 4. In this embodiment, the annular groove 24 can be formed after the carrier substrate 4 is subsequently removed and before the piezoelectric layer 22 is formed. In other embodiments, the annular groove 24 can be formed by etching after the first electrode 21 is formed and before the electrode lead structure 3 is formed.

[0096] Reference Figure 9 An electrode lead-out structure 3 and a support layer 12 having a first cavity are formed on the first electrode 21. The specific steps may refer to those described in Example 4, wherein the annular sacrificial protrusion 32' fills the annular groove and covers the first electrode 21 in the peripheral area of ​​the annular groove.

[0097] Reference Figure 10 , 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 extending 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 extending 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, with the first groove facing the annular groove. 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 of Example 4 and will not be further described here.

[0098] 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 4, and are not described again here.

[0099] In another embodiment, referring to Figure 11-13 The method for forming the first electrode 21, the piezoelectric layer 22, and the second electrode 23 further includes: providing a carrier substrate 4; sequentially forming the piezoelectric layer 22 and the first electrode 21 on the carrier substrate 4; after forming the support layer 12 on the first electrode 21, removing the carrier substrate 4; then forming the second electrode 23 on the piezoelectric layer 22; forming the electrode lead-out structure 3 on the first electrode 21; forming the electrode lead-out structure 3 on the first electrode 21 includes: forming the electrode lead-out structure 3 on the first electrode 21 after forming the first electrode 21 and before forming the support layer 12. Specifically:

[0100] Reference Figure 11 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.

[0101] Reference Figure 12 An electrode lead-out structure 3 and a support layer 12 having a first cavity are formed on the first electrode 21. The specific steps are described in Example 4 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.

[0102] Reference Figure 13 , remove the carrier substrate, and flip the above structure over to form a second electrode 23 by deposition on the piezoelectric layer 22. It should be noted that after forming the second electrode 23, the annular sacrificial protrusion also needs to be removed.

[0103] 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 4, and are not described again here. Example 5

[0104] Example 5 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 14This is a schematic diagram of the structure of a thin film bulk acoustic wave resonator manufactured according to the method for manufacturing a thin film bulk acoustic wave resonator according to this embodiment. This embodiment differs from Example 4 in that the piezoelectric layer 22 in Example 4 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 4. The remaining steps refer to those in Example 4. The beneficial effects of a complete piezoelectric layer 22 can be seen in Example 2 above and are not further described here. Example 6

[0105] Example 6 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 15-21 This 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 4 is that in Example 4, 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 23 are provided with an electrode lead-out structure 3. Specifically:

[0106] Reference Figure 15-17 In this embodiment, 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, referring to Figure 15 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 16 Then, a support layer 12 having a first cavity 121 is formed on the first electrode 21 by a sacrificial layer method, the carrier substrate 4 is removed, and the above structure is flipped. 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 part 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. Figure 17 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 4 and are not repeated here.

[0107] 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.

[0108] 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.

[0109] In another embodiment, referring to Figure 18-19 , perform the steps of the above embodiment 4, and after removing the carrier substrate and before removing the annular sacrificial protrusion on the first electrode 21, etch the second electrode 23 to form an annular groove penetrating the second electrode 23, refer to Figure 18 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 19 The first sacrificial material and the annular sacrificial protrusion are removed. The specific formation process corresponding to the above steps refers to Example 4 and will not be repeated here. The remaining steps of the thin film bulk acoustic resonator refer to the above Example 4 and will not be repeated here.

[0110] In another embodiment, referring to Figure 20-21 , forming the second electrode 23, the piezoelectric layer 22, and the first electrode 21 on the carrier substrate 4 in sequence; forming an electrode lead structure on the first electrode 21, referring to Figure 20A support layer 12 having a first cavity 121 is formed by using a sacrificial layer; the carrier substrate 4 is removed and the structure is flipped over. A groove is etched on the second electrode 23 to pass through the second electrode 23, the piezoelectric layer 22 and the first electrode 21; 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, as shown in FIG. Figure 21 The sacrificial material is removed. The specific formation process of the above steps is referred to Example 4 and will not be repeated here. Example 7

[0111] Example 7 provides a method for manufacturing a thin film bulk acoustic resonator. Figure 22 This is a schematic diagram of the structure of a thin film bulk acoustic wave resonator manufactured according to the method for manufacturing a thin film bulk acoustic wave resonator according to this embodiment. This embodiment differs from Example 6 in that the piezoelectric layer 22 in Example 6 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 6 is omitted, and the remaining steps refer to those in Example 6. The beneficial effects of having a complete piezoelectric layer 22 can be seen in Example 2 above and are not further described here.

[0112] In the above-mentioned Embodiment 6 and Embodiment 7, both the first electrode 21 and the second electrode 23 are provided with an electrode lead-out structure 3 . The relative relationship between the two is as described in Embodiment 1 and will not be described again here. Example 8

[0113] Embodiment 8 of the present invention provides a method for manufacturing a thin film bulk acoustic resonator. Figure 23 1 is a schematic structural diagram 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 embodiments 4-7 is that any of embodiments 4-7 form a first cavity 121 in the support layer 12, while this embodiment forms an acoustic reflector in the support layer 12, specifically including:

[0114] 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;

[0115] S02: forming an annular groove penetrating the corresponding electrode on at least one of the first electrode and the second electrode;

[0116] 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 on the corresponding electrode;

[0117] S04: forming a support layer having an acoustic reflection mirror on the first electrode;

[0118] S05: removing the annular sacrificial protrusion to form an annular gap, and the area surrounded by the annular gap is the effective resonance area.

[0119] In this embodiment, the method for forming the support layer 12 having the acoustic reflector 51 on the first electrode 21 includes sequentially forming a plurality of alternating high and low acoustic impedance reflective film layers on the first electrode 21, wherein the reflective film layers cover a portion of the first electrode 21 or cover a portion of the first electrode 21 and the electrode lead structure 3 located on the first electrode 21. Furthermore, a second substrate 5 may be formed on the support layer 12. The remaining steps may refer to any of the above-mentioned embodiments 4-7 and are not further described here. Example 9

[0120] Embodiment 9 of the present invention provides a filter comprising at least one FBAR as described above. 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.

[0121] 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.

[0122] 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 thin film bulk acoustic resonator, characterized in that: include: A piezoelectric stack structure, comprising a first electrode, a piezoelectric layer, and a second electrode stacked sequentially from bottom to top, wherein at least one of the first electrode and the second electrode has an annular groove extending through the corresponding electrode; An electrode lead-out structure is provided on the corresponding electrode provided with the annular groove, and the electrode lead-out structure covers at least a portion of the annular groove and extends to the invalid resonance zone. The electrode lead-out structure includes an annular arch bridge protruding away from the piezoelectric layer, and the inner surface of the arch bridge forms an annular gap, and the annular gap is opposite to the annular groove.

2. The 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.

3. The 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.

4. The thin film bulk acoustic resonator according to claim 1, wherein The annular space is a closed annular space.

5. The thin film bulk acoustic resonator according to claim 1, wherein The piezoelectric stack structure is located on a first substrate having a first cavity, and the piezoelectric stack structure covers the first cavity; Alternatively, the piezoelectric stack structure is located on a second substrate having an acoustic mirror.

6. The thin film bulk acoustic resonator according to claim 5, characterized in that The periphery of the first electrode and / or the second electrode extends to the first cavity or the first substrate at the periphery of the acoustic reflector.

7. The thin film bulk acoustic resonator according to claim 5, wherein The electrode lead-out structure extends from the periphery of the annular gap to the first cavity or the first substrate at the periphery of the acoustic reflector.

8. The 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.

9. The thin film bulk acoustic resonator according to claim 8, characterized in that The electrode lead-out structure and the corresponding electrode without the electrode lead-out structure are at least partially staggered with each other at the periphery of the annular gap.

10. The thin film bulk acoustic resonator according to claim 1, wherein The first electrode and the second electrode are both provided with an electrode lead-out structure. 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.

11. The thin film bulk acoustic resonator according to claim 10, wherein: The electrode lead-out structure provided on the first electrode and the electrode lead-out structure provided on the second electrode are at least partially staggered with respect to each other at the periphery of the annular gap; The arched bridge structure of the electrode lead-out structure provided on the first electrode is arranged opposite to the arched bridge structure of the electrode lead-out structure provided on the second electrode.

12. The thin film bulk acoustic resonator according to claim 5, wherein The piezoelectric layer is a complete film layer, covering the first cavity and extending outside the first cavity; or, A first groove is provided in the piezoelectric layer, and the first groove is opposite to the annular groove.

13. The thin film bulk acoustic resonator according to claim 12, wherein: The first groove is a closed ring, and the piezoelectric layer in the effective resonance region and the piezoelectric layer outside the effective resonance region are isolated from each other; or, The first groove is in the shape of a discontinuous ring, and the piezoelectric layer in the effective resonance region is isolated from the piezoelectric layer outside the effective resonance region by the discontinuity.

14. The thin film bulk acoustic resonator according to claim 5, wherein The first substrate includes a base and a support layer, the support layer and the piezoelectric stack structure are sequentially stacked on the base, and the first cavity is provided in the support layer; or, The first substrate includes a semiconductor substrate, and the first cavity is disposed in the semiconductor substrate.

15. The thin film bulk acoustic resonator according to claim 14, wherein: The first cavity extends to part of the thickness of the support layer; or The first cavity penetrates the supporting layer.

16. The 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.

17. The 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.

18. 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 support layer having a sacrificial layer on the first electrode; The sacrificial layer is removed to form a first cavity; the annular sacrificial protrusion is removed to form an annular gap, and the annular gap is opposite to the annular groove.

19. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: The method of forming the first electrode, the piezoelectric layer and the second electrode includes: providing a carrier substrate; forming the second electrode, the piezoelectric layer and the first electrode in sequence on the carrier substrate; After forming a support layer on the first electrode, 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 supporting 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; or, providing a carrier substrate; forming the first electrode on the carrier substrate; After the first electrode forms a supporting layer, removing the carrier substrate; Then, 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: after removing the carrier substrate, 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 forming a support layer on the first electrode, 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.

20. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, 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.

21. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: The method of forming an electrode lead-out structure on a corresponding electrode, covering the annular sacrificial protrusion and having an edge overlapping the edge of the effective resonance region electrode, comprises: Depositing a conductive material on the corresponding electrode to form the electrode lead-out structure, wherein the electrode lead-out structure covers the corresponding electrode and the annular sacrificial protrusion formed 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.

22. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: The periphery of the first electrode and / or the second electrode extends to the support layer outside the first cavity.

23. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: One of the first electrode and the second electrode is formed with the electrode lead-out structure, and when forming the electrode lead-out structure, the electrode lead-out structure is further patterned, and when forming the corresponding electrode without the electrode lead-out structure, the corresponding electrode is further 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 at the periphery of the annular gap; or, The first electrode and the second electrode are both provided with an electrode lead-out structure, and forming the electrode lead-out structure further includes patterning the electrode lead-out structure so that the electrode lead-out structure provided on the first electrode and the electrode lead-out structure provided on the second electrode are at least partially staggered relative to each other at the periphery of the annular gap; The arched bridge structure of the electrode lead-out structure provided on the first electrode is arranged opposite to the arched bridge structure of the electrode lead-out structure provided on the second electrode.

24. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, 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, where the first groove is opposite to the annular groove.

25. The method for manufacturing a thin film bulk acoustic resonator according to claim 24, wherein: The first groove is a closed ring, and the piezoelectric layer in the effective resonance region and the piezoelectric layer outside the effective resonance region are isolated from each other; or, The first groove is in a discontinuous ring shape, and the piezoelectric layer in the effective resonance region is isolated from the piezoelectric layer outside the effective resonance region by the discontinuity.

26. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: The material of the annular sacrificial protrusion includes phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, amorphous carbon, polyimide or photoresist.

27. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: The method of forming a support layer having a sacrificial layer on the first electrode includes: forming a sacrificial layer on the first electrode, covering a portion of the first electrode not provided with the electrode lead-out structure or covering a portion of the electrode lead-out structure and a portion corresponding to the first electrode; forming a supporting layer to cover the sacrificial layer and the periphery of the sacrificial layer; The sacrificial layer is removed to form a first cavity.

28. 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 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; forming a support layer having an acoustic reflection mirror on the first electrode; The annular sacrificial protrusion is removed to form an annular gap, and the annular gap is opposite to the annular groove.

29. A filter, characterized in that The device comprises at least one thin film bulk acoustic resonator according to any one of claims 1 to 17.

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