WO2021254342A1

WO2021254342A1 - Thin-film bulk acoustic wave resonator and manufacturing method therefor

Info

Publication number: WO2021254342A1
Application number: PCT/CN2021/100169
Authority: WO
Inventors: 黄河
Original assignee: 中芯集成电路（宁波）有限公司上海分公司
Priority date: 2020-06-16
Filing date: 2021-06-15
Publication date: 2021-12-23

Abstract

The present invention relates to a thin-film bulk acoustic wave resonator and a manufacturing method therefor. The thin-film bulk acoustic wave resonator comprises: a first substrate provided with a first cavity; a piezoelectric stacked structure, which comprises, from bottom to top, a first electrode, a piezoelectric layer and a second electrode, which are successively stacked, wherein the piezoelectric layer covers the first cavity, edges of both the first electrode and the second electrode are located within the boundary of an area defined by the first cavity, and an effective resonance area comprises an area in which the first electrode, the piezoelectric layer and the second electrode overlap with each other in a direction perpendicular to the surface of the piezoelectric layer; a first electrode lead-out structure, which is connected to the edge of the first electrode, extends to an ineffective resonance area to serve as a first signal connection end, and performs enclosing to form a first gap with the piezoelectric stacked structure at an edge of the effective resonance area; and a second electrode lead-out structure, which is connected to the edge of the second electrode, extends to the ineffective resonance area to serve as a second signal connection end, and performs enclosing to form a second gap with the piezoelectric stacked structure at the edge of the effective resonance area. By means of the present invention, a Q value is improved by means of eliminating clutter on the boundary of an effective resonance area.

Description

Thin film bulk acoustic wave resonator and manufacturing method thereof

Technical field

The invention relates to the field of semiconductor device manufacturing, in particular to a thin-film bulk acoustic wave resonator and a manufacturing method thereof.

Background technique

Since the analog radio frequency communication technology was developed in the early 1990s, radio frequency front-end modules have gradually become the core components of communication equipment. Among all RF front-end modules, the filter has become the component with the strongest growth momentum and the greatest development prospects. With the rapid development of wireless communication technology, 5G communication protocols have become more mature, and the market has also put forward more stringent standards for various aspects of the performance of radio frequency filters. The performance of the filter is determined by the resonator unit that composes the filter. Among the existing filters, the film bulk acoustic resonator (FBAR) has the characteristics of small size, low insertion loss, large out-of-band suppression, high quality factor, high operating frequency, large power capacity, and good resistance to electrostatic shock. Become one of the most suitable filters for 5G applications.

Generally, the film bulk acoustic wave resonator includes two film electrodes, and a piezoelectric film layer is arranged between the two film electrodes. Its working principle is to use the piezoelectric film layer to generate vibration under an alternating electric field. The bulk acoustic wave propagating in the thickness direction of the electric film layer is transmitted to the interface between the upper and lower electrodes and the air to be reflected back, and then reflected back and forth inside the film to form an oscillation. When the sound wave propagates in the piezoelectric film layer exactly an odd multiple of the half wavelength, a standing wave oscillation is formed.

technical problem

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 radio frequency systems.

Technical solutions

The purpose of the present invention is to provide a thin film bulk acoustic wave resonator and a manufacturing method thereof, which can improve the quality factor of the thin film bulk acoustic wave resonator, thereby improving the performance of the device.

In a first aspect, the present invention proposes a thin film bulk acoustic resonator, which includes: a first substrate in which a first cavity is provided; a piezoelectric laminate structure, which includes a first substrate stacked in sequence from bottom to top An electrode, a piezoelectric layer, and a second electrode, the edges of the first electrode and the second electrode are all located within the boundary of the region enclosed by the first cavity, and the effective resonance region includes the first electrode, the The area where the electrical layer and the second electrode overlap each other in the direction perpendicular to the surface of the piezoelectric layer; the first electrode lead-out structure connects the edge of the first electrode and extends to the ineffective resonance area as the first signal connection end. The edge of the effective resonance region and the piezoelectric laminate structure enclose a first gap; a second electrode lead-out structure is connected to the edge of the second electrode and extends to the ineffective resonance region as a second signal connection terminal, A second gap is enclosed with the piezoelectric laminate structure at the edge of the effective resonance region.

In a second aspect, the present invention provides a method for manufacturing a thin film bulk acoustic resonator, including: providing a temporary substrate; sequentially forming a second electrode layer, a piezoelectric layer, and a first electrode on the temporary substrate, and An electrode is located in the effective resonance region; a first electrode extraction structure is formed. The first electrode extraction structure is connected to the edge of the first electrode and extends to the ineffective region as the first signal connection end. The electrical layer and the first electrode enclose a first gap; a first substrate including a first cavity is formed on the piezoelectric layer, the first substrate covers a portion of the first electrode extraction structure, and the first An electrode is located within the boundary of the region enclosed by the first cavity; the temporary substrate is removed; the second electrode layer is patterned to form a second electrode; the effective resonance region includes the first electrode, The area where the electrical layer and the second electrode overlap each other in the direction perpendicular to the surface of the piezoelectric layer; forming a second electrode lead-out structure, the second electrode lead-out structure is connected to the edge of the second electrode and extends to the ineffective area as the first The two signal connection ends enclose a second gap with the piezoelectric layer and the second electrode at the edge of the effective resonance zone.

In a third aspect, another method of manufacturing a thin film bulk acoustic resonator of the present invention includes: providing a first substrate; forming a first cavity, a first sacrificial layer, and a first electrode extraction structure in the first substrate , The first sacrificial layer fills the first cavity, the upper surface of the first sacrificial layer is flush with the upper surface of the first substrate, and the first electrode extraction structure is located on the first lining The bottom and the first sacrificial layer; forming a first dielectric layer, a first electrode, a piezoelectric layer, and a second electrode on the first substrate, wherein the first electrode is located at the boundary of the first cavity Inside, the first dielectric layer is located between the piezoelectric layer and the first substrate, the first dielectric layer surrounds the first electrode and forms a closed ring, the first electrode, the piezoelectric The area where the layer and the second electrode overlap each other in the direction perpendicular to the surface of the piezoelectric layer is the effective resonance region; the edge of the first electrode extraction structure connecting the first electrode extends to the ineffective resonance region as the first signal connection A first gap is formed between the boundary of the effective resonance region and the piezoelectric laminate structure; a second electrode lead-out structure is formed, and the second electrode lead-out structure is connected to the edge of the second electrode and extends to the ineffective resonance The area is used as a second signal connection end, and a second gap is formed with the piezoelectric layer and the second electrode at the edge of the effective resonance area; the first sacrificial layer is removed.

Beneficial effect

The beneficial effect of the thin film bulk acoustic resonator of the first aspect of the present invention is that by adopting a separate first electrode extraction structure and a second electrode extraction structure on the first electrode side and the second electrode side, respectively, the first electrode extraction structure and the second electrode extraction structure The two-electrode extraction structure respectively forms a first gap and a second gap in the boundary region of the effective resonance region. The first gap and the second gap can achieve the effect of eliminating clutter at the boundary of the effective resonance region, thereby increasing the Q value of the resonator.

Further, the first electrode lead-out structure and the second electrode lead-out structure can reduce impedance and enhance heat conduction.

Furthermore, the piezoelectric layer is provided with air gaps, so that the edge of the piezoelectric layer is exposed to the air, which can suppress the loss of the transverse wave.

Further, when the piezoelectric layer is a complete film layer, the structural strength of the resonator can be increased; the piezoelectric layer is formed on the flat electrode layer, which can make the piezoelectric layer have better lattice orientation and improve the piezoelectric layer The piezoelectric characteristics, thereby improving the overall performance of the resonator.

Further, a first protrusion is provided on the surface of the first electrode and/or a second protrusion is provided on the surface of the second electrode. The area where the first protrusion and the second protrusion are located forms an acoustic impedance mismatch area, which can effectively resonate The boundary of the zone is mismatched with the acoustic impedance inside the effective resonance zone; the projection of the first protrusion and the first overhead portion on the surface of the piezoelectric layer is a closed or gap ring or the second protrusion and the second overhead portion are in compression The projection of the surface of the electrical layer is a closed ring or a ring with gaps, which can jointly suppress the leakage of lateral clutter, and further improve the quality factor of the resonator.

Further, the first dielectric layer and the second dielectric layer are respectively formed on the upper and lower surfaces of the piezoelectric layer, which can improve the bonding effect when the top cover is subsequently formed, and the arrangement of the first dielectric layer and the second dielectric layer can also be improved. The overall mechanical strength of the resonator.

The beneficial effect of the method for manufacturing the thin film bulk acoustic resonator of the second aspect of the present invention is that the second electrode layer and the piezoelectric layer are sequentially formed on the surface of the temporary substrate, so that the piezoelectric layer can be formed on the flat second electrode layer. Above, it is ensured that the piezoelectric layer has a better crystal lattice orientation, and the piezoelectric characteristics of the piezoelectric layer are improved, thereby improving the performance of the resonator. By first forming the first electrode and the first electrode extraction structure on the first surface of the piezoelectric layer, and then forming the second electrode and the second electrode extraction structure on the second surface, the two sides of the piezoelectric layer are patterned with electrodes The process avoids the etching of the piezoelectric layer during the electrode formation process, ensures the integrity and flatness of the piezoelectric layer, reduces the impact on the piezoelectric layer, thereby improving the performance of the resonator; and this method is compatible with the main process of the resonator Compatible, the process is simple.

The beneficial effect of the method for manufacturing the thin film bulk acoustic resonator of the third aspect of the present invention is that the surface of the first electrode and the first electrical connection structure is adjusted by forming the first dielectric layer so that they are flush, thereby ensuring The flatness of the piezoelectric layer formed on the first electrode and the first electrical connection structure. At the same time, the first dielectric layer is located in the ineffective area and surrounds the first electrode, so that the surface of the piezoelectric layer in the ineffective area is flat, providing a piezoelectric laminate The stability of the structure, thereby improving the performance of the resonance region.

Further, after the first conductive layer is formed, the first electrode lead-out structure is formed through a planarization process, which can ensure that the first dielectric layer and the first electrode formed subsequently are formed on a flat surface, and the first dielectric layer is formed. After the first electrode, by flattening the surface of the first dielectric layer and the first electrode, the upper and lower surfaces of the first dielectric layer and the first electrode formed can be flat and flat, and at the same time, the subsequent The formed piezoelectric layer is also formed on a flat surface, so as to ensure the flatness of the formed piezoelectric layer, so that the piezoelectric layer has good piezoelectric performance, and thus the performance of the resonator is improved.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[Corrected according to Rule 91 02.07.2021]
Figure 1 shows a schematic cross-sectional structure diagram of a thin film bulk acoustic resonator according to Embodiment 1 of the present invention; Figure 1A shows a top view along the X direction of Figure 1; The cross-sectional structure diagram of the thin film bulk acoustic resonator of the first protrusion, the second protrusion, the first dielectric layer and the second dielectric layer; FIG. 2A is a top view of FIG. 2 along the X direction; FIG. 3 shows an embodiment of the present invention 1 is a schematic cross-sectional structure diagram of a thin film bulk acoustic resonator including a top cover; FIG. 4 shows a cross-sectional structure diagram of a thin film bulk acoustic resonator including an air gap according to Embodiment 1 of the present invention; FIG. 5 Shows a schematic cross-sectional structure diagram of a thin film bulk acoustic resonator according to Embodiment 2 of the present invention; FIG. 6 shows a thin film body including a dielectric layer, a first protrusion, and a second protrusion according to Embodiment 2 of the present invention Schematic diagram of the cross-sectional structure of the acoustic wave resonator; Figures 7-18 show a schematic diagram of the structure corresponding to the corresponding steps of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 3 of the present invention; Figures 19-22 show the implementation of the present invention The structure diagram corresponding to the corresponding steps of the method for manufacturing another thin film bulk acoustic wave resonator of Example 3; FIGS. 23-30 show the structure corresponding to the corresponding steps of the method for manufacturing a thin film bulk acoustic wave resonator in the embodiment of the present invention. Schematic.

Embodiments of the present invention

The currently manufactured cavity-type thin-film bulk acoustic resonators suffer from transverse wave loss and insufficient structural strength, so that the quality factor (Q) cannot be further improved, and the yield is low. Therefore, they cannot meet the needs of high-performance radio frequency systems.

In order to solve the above problems, the present invention provides a thin film bulk acoustic resonator, which adopts separate first electrode extraction structure and second electrode extraction structure on the first electrode side and the second electrode side, respectively, the first electrode extraction structure and the second electrode extraction structure The two electrode lead-out structures are respectively located on both sides of the effective resonance area to form an oblique symmetric structure. The first electrode lead-out structure and the second electrode lead-out structure respectively form a first gap and a second gap at the boundary area of the effective resonant area. The first gap and the second gap The gap can achieve the effect of eliminating clutter at the boundary of the effective resonance region, thereby increasing the Q value of the resonator.

The film bulk acoustic resonator and the manufacturing method thereof of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present invention will be clearer. However, it should be noted that the concept of the technical solution of the present invention can be implemented in many different forms and is not limited to the specific implementation set forth herein. example. The drawings all adopt a very simplified form and all use imprecise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

The terms "first", "second", etc. in the specification and claims are used to distinguish between similar elements, and are not necessarily used to describe a specific order or time sequence. It is to be understood that, under appropriate circumstances, these terms so used can be replaced, for example, to enable the embodiments of the present invention described herein to be operated in other sequences than described or shown herein. Similarly, if the method described herein includes a series of steps, and the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the described steps may be omitted and/or some are not described herein The other steps can be added to the method. If the components in a certain drawing are the same as those in other drawings, although these components can be easily identified in all the drawings, in order to make the description of the drawings more clear, this specification will not describe all the same components. The reference numbers are shown in each figure.

Example 1

FIG. 1 is a schematic cross-sectional structure diagram of a thin film bulk acoustic wave resonator provided by an embodiment of the present invention. Please refer to FIG. 1. The thin film bulk acoustic resonator includes a first substrate 1. There is a first cavity 121; the piezoelectric laminated structure 3, from bottom to top, includes a first electrode 31, a piezoelectric layer 32, and a second electrode 33 that are sequentially stacked. The edges of the first electrode 31 and the second electrode 33 are all located in the first Within the boundary of the area enclosed by a cavity 121, the effective resonance area includes the area where the first electrode 31, the piezoelectric layer 32, and the second electrode 33 overlap each other in the direction perpendicular to the surface of the piezoelectric layer 32. The ineffective resonance area is the effective resonance. Area outside the region; the first electrode lead structure 4, connected to the edge of the first electrode 31 and extended to the ineffective resonant area as the first signal connection end, the edge of the effective resonant area and the piezoelectric laminate structure 3 to form a first gap 43; The second electrode lead-out structure 5 is connected to the edge of the second electrode 33 and extends to the ineffective resonant area as a second signal connection end. The edge of the effective resonant area and the piezoelectric laminated structure 3 enclose a second gap 53.

In this embodiment, the first substrate 1 has a two-layer structure, including a base 11 and a support layer 12. The support layer 12 and the piezoelectric laminate structure 3 are sequentially laminated on the base 11, and the first cavity 121 is provided on the support layer 12. middle. It should be noted that the support layer 12 may be combined with the substrate 11 through a bonding layer or a deposition method. In other embodiments, the first substrate 1 may also have a single-layer structure, and the first cavity 121 is formed in the first substrate 1.

The piezoelectric laminate structure 3 is provided above the first cavity 121, the piezoelectric layer 32 covers the first cavity 121, and the edges of the first electrode 31 and the second electrode 33 are located at the boundary of the area enclosed by the first cavity 121 Within.

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

In order to facilitate subsequent input/output of electrical signals, it also includes a first electrode lead-out structure 4 and a second electrode lead-out structure 5. The first electrode lead-out structure 4 is used to connect the edge of the first electrode 31 and extend to the ineffective resonance zone as the second A signal connection terminal, the edge of the first electrode 31 and the piezoelectric layer 32 enclose a first gap 43, the second electrode lead-out structure 5 is used to connect the edge of the second electrode 33 and extend to the ineffective resonance area as a second signal connection At the end, the edge of the second electrode 33 and the piezoelectric layer 32 define a second gap 53. The first signal connection terminal and the second signal connection terminal serve as signal input terminals or signal output terminals.

In this embodiment, the height of the first gap 43 is greater than the thickness of the first electrode 31, so that all edges of the first electrode 31 are exposed to the air. Similarly, the height of the second gap 53 is also greater than that of the second electrode 33. The thickness of the second electrode 33 is exposed to the air. In other embodiments, the height of the first gap 43 may be equal to or less than the thickness of the first electrode 31; the height of the second gap 53 may also be equal to or less than the thickness of the second electrode 33. The best effect is when the edges of the first electrode 31 are all exposed to the air, and when the edges of the second electrode 33 are all exposed to the air. The edges of the first electrode 31 and the second electrode 33 both form a reflective interface with the air, which makes the acoustic impedance mismatch, suppresses the leakage of the transverse wave, and achieves the effect of eliminating the boundary clutter of the effective resonance region, thereby improving the quality factor (Q value) of the resonator . In addition, the energy coupled to the first electrode 31 and the second electrode 33 is also reduced, so as to prevent the loss of the first electrode 31 and/or the second electrode 33 from affecting the quality factor (Q value) of the resonator, thereby improving The quality factor (Q value) of the resonator in the entire operating frequency band. In this embodiment, the projections of the first gap 43 and the second gap 53 are located in the first cavity 121. In other embodiments, the projections of the first gap 43 and the second gap 53 may also be located outside the first cavity 121.

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

The first electrode extraction structure 4 includes: a first overhead portion 41 enclosing a first gap 43, a first overlapping portion 42 connected to the first overhead portion 41 and extending to the ineffective resonance zone, and the first overlapping portion 42 serves as a first Signal connection terminal. Specifically, the first electrode lead-out structure 4 includes a first overhead portion 41 and a first overlap portion 42. The first overhead portion 41 and the piezoelectric laminated structure 3 enclose a first gap 43, and the first overlap portion 42 is connected to the first gap 43. An overhead portion 41 extends to the ineffective resonance zone, and the first overlap portion 41 is connected for connecting a first external signal.

In this embodiment, referring to FIG. 1, the piezoelectric layer 32 covers the first cavity 121, and the surface of the first lap portion 42 facing the piezoelectric layer 32 is flush with the surface of the first electrode 31 facing the piezoelectric layer 32; and/ Or, the surface of the second lap portion 52 facing the piezoelectric layer 32 is flush with the surface of the second electrode 52 facing the piezoelectric layer 32. The surfaces of the first lap portion 42 and the second lap portion 52 facing the piezoelectric layer 32 are flush with the surface of the piezoelectric layer 32, which can ensure the overall flatness of the piezoelectric laminate structure and ensure the performance of the resonator.

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

In this embodiment, the first overhead portion 41 surrounds the outer circumference of the first electrode 31. In other embodiments, the first overhead portion 41 may also be connected to one or more edges of the first electrode 31. At this time, one of the first overhead portions 41 connecting the first electrode 31 and one first overlap portion 42 The number can also be more than one.

Refer to FIG. 1A, and FIG. 1A is a top view of FIG. 1 along the X direction. Referring to FIG. 1A, the first overlapping portion 42 and the first overhead portion 41 are both disposed on one side of the first electrode 31. To

1A, the projection of the first overhead portion 41 on the piezoelectric layer 32 is in the shape of a strip or a plane. When it is in the shape of a plane, it can be continuously or intermittently distributed on one or more edges of the first electrode 31; likewise, the first The projection of an overlapping portion 42 on the piezoelectric layer 32 can also be strip-shaped or planar; correspondingly, the combination of the first overhead portion 41 and the first overlapping portion 42 can also be multiple, for example, the first overhead portion 41 and the first overlapping portion 42 are both strip-shaped or both planar, or one of them is a strip-shaped structure, the other is a planar structure, and further, the first overhead portion 41 and the first overlapping portion 42 are both The surface shape increases the contact area between the first electrode 31 and the first electrode lead-out structure 4, which is beneficial to reduce the impedance and improve the Q value of the resonator.

Continuing to refer to FIG. 1, the second electrode extraction structure 5 includes: a second overhead portion 51 enclosing a second gap 53, a second overlapping portion 52 connected to the second overhead portion 51 and extending to the ineffective resonance zone, and the second overlapping portion Section 52 serves as a second signal connection terminal.

Specifically, the second electrode extraction structure 5 includes a raised second overhead portion 41 and a second overlap portion 52, the second overhead portion 51 and the piezoelectric laminate structure 3 enclose a second gap 53, the second overlap portion 52 is connected to the second overhead part 51 and extends to the ineffective resonance zone.

In this embodiment, the second overlapping portion 52 surrounds the outer circumference of the second electrode 33. In other embodiments, the second overlapping portion 52 is provided on a part of the outer circumference of the second electrode 33.

In this embodiment, the second overhead portion 51 surrounds the outer circumference of the second electrode 33. In other embodiments, the second overhead portion 51 is connected to one or more edges of the second electrode 33. At this time, the number of the second overhead portions 51 connecting the second electrode 33 and a second overlapping portion 52 is still It can be more than one.

1A, the second overhead portion 51 is connected to two sides of the second electrode 33, and the second overlap portion 52 is led out from one side. The structure of the second overhead portion 51 and the second overlapping portion 52 and the positional relationship with the second electrode refer to the structure of the first overhead portion 41 and the first overlapping portion 42 and the positional relationship with the first electrode 31. I won't repeat it here.

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

The materials of the first electrode extraction structure 4 and the first electrode 31 and/or the materials of the second electrode extraction structure 5 and the second electrode 33 may be the same or different. The first electrode extraction structure 4 and/or the second electrode extraction structure 5 are adopted A metal material with low impedance to ensure a good electrical connection effect, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, and copper.

In another embodiment, referring to FIG. 2, the film bulk acoustic resonator further includes: a first protrusion 6 and a second protrusion 7, the first protrusion 6 is located on the first electrode 31 and distributed along the edge of the effective resonance region , The projection of the first protrusion 6 and the first gap 43 on the surface of the piezoelectric layer 32 forms a closed or gap ring; the second protrusion 7 is located on the second electrode 33 and distributed along the edge of the effective resonance zone. The projections of the two protrusions 7 and the second gap 53 on the surface of the piezoelectric layer 32 form a closed ring or a gap with a gap. Specifically, the first protrusion 6 is a continuous whole or includes a plurality of intermittently arranged first sub-protrusions, and the second protrusion 7 is a continuous whole or includes a plurality of intermittently arranged second sub-protrusions.

2A, when the first protrusion 6 is a continuous whole, the projection of the first protrusion 6 on the piezoelectric layer 32 is a continuous pattern, and when the second protrusion 7 is a continuous whole, the second protrusion 7 is in the piezoelectric The projection of the layer 32 is a continuous pattern. It should be understood that when the projection of the first protrusion 6 and the second protrusion 7 on the piezoelectric layer 32 is a continuous pattern, it is more beneficial to prevent the lateral leakage of sound waves. When the first protrusion 6 includes a plurality of first sub-protrusions intermittently arranged; and/or, the second protrusion 7 includes a plurality of second sub-protrusions intermittently arranged, the first protrusion 6 is on the piezoelectric layer 32 The projection of is a discontinuous figure; and/or, the projection of the second protrusion 7 on the piezoelectric layer 32 is a discontinuous figure. When the first protrusion 6 includes a plurality of first sub-protrusions, and the second protrusion 7 includes a plurality of second sub-protrusions, the first protrusion 6 and the second protrusion 7 are on the plane where the piezoelectric layer 32 is located. The projections can be overlapped, and the projections form a ring with gaps. In other embodiments, the projections of the first protrusion 6 and the second protrusion 7 on the plane where the piezoelectric layer 32 is located may not overlap.

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

2 and 2A, in another embodiment, the film bulk acoustic wave resonator further includes: a first dielectric layer 95 and/or a second dielectric layer 96, the first dielectric layer 95 is located on the first substrate 1 and the pressure Between the electrical layers 32, the first dielectric layer 95 is located in the ineffective resonance zone and is separated from the first electrode 31, the first dielectric layer 95 and the first overlapping portion 42 surround the first electrode 31; the second dielectric layer 96 is located in the pressure Above the electrical layer 32, the second dielectric layer 96 and the second overlap portion 52 surround the second electrode 33, and the second dielectric layer 96 and the second overlap portion 52 surround the second electrode 33. The first dielectric layer 95 and the second dielectric layer 96 can improve the bonding effect when the top cover is subsequently bonded; at the same time, the arrangement of the first dielectric layer 95 and the second dielectric layer 96 can also improve the overall mechanical strength of the resonator. It is worth noting that when the upper surface of the first dielectric layer 95 is flush with the upper surface of the first overlap portion 42 and the upper surface of the second dielectric layer 96 is flush with the upper surface of the second overlap portion 52, the overall The mechanical strength is the best. In addition, the first dielectric layer 95 may be continuously connected to the first overlapping portion 42, that is, the first dielectric layer 95 and the first overlapping portion 42 are connected on the surface of the piezoelectric layer 32, and surround the surface of the piezoelectric layer 32. It is ring-shaped and covers the area outside the edge of the effective resonance zone; the second dielectric layer 96 can be continuously connected with the second overlapping portion 52, that is, the second dielectric layer 96 and the second overlapping portion 52 are on the surface of the piezoelectric layer 32 They are connected to each other and form a ring on the surface of the piezoelectric layer 32, and cover the area outside the edge of the effective resonance area. When the first dielectric layer 95 and the first overlap portion 42 are continuously connected, and the second dielectric layer 96 and the second overlap portion 52 are continuously connected, it is more beneficial to ensure the flatness of the piezoelectric laminate structure 3, and Increase the strength of the resonator. The first dielectric layer 95 can be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc. The material of the second dielectric layer 96 can be based on The selection of the material of the first dielectric layer 95 will not be repeated here. In this embodiment, the material of the second dielectric layer 96 may be the same as that of the first dielectric layer 95.

It should be understood that the protrusion structure and the dielectric layer structure are independent of each other. In other embodiments, they may only include the protrusion structure or only the dielectric layer structure. When the first protrusion 6, the second protrusion 7, the first dielectric layer 95, and the second dielectric layer 96 are included at the same time, it can be more beneficial to suppress transverse wave leakage, balance temperature drift, improve mechanical strength, and improve the top cover bonding Effect.

In another embodiment, referring to FIG. 3, in order to prevent the layers exposed in the upper space from being polluted by the external environment, a top cover 8 is further provided above the piezoelectric laminate structure, and a second cavity 811 is provided in the top cover 8. The second cavity 811 is located above the first cavity 121, and the edge of the second electrode 33 is located in the second cavity 811.

Specifically, the top cover 8 may be an integral structure, and the second cavity 811 does not penetrate the top cover 8; or, the top cover includes the bonding layer 81 and the second substrate 82, the second cavity 811 is formed on the bonding layer 81, and the second cavity 811 is formed on the bonding layer 81. The two cavities 811 may or may not penetrate the bonding layer 81, and the second substrate 82 is bonded above the bonding layer 81. The bonding layer 81 can be made of silicon oxide, silicon nitride, silicon oxynitride, ethyl silicate, etc., or a light-curing material or a heat-curing material and other adhesives, such as die tth film (DF) or dry film (Dry Film). The material of the bonding layer 81 and the material of the second substrate 82 may be the same, and the two are an integral structure, that is, the top cover 8 is an integral structure, and the second cavity 811 is formed by forming a space in the top cover 8.

In another embodiment, referring to FIG. 4, the cross-section of FIG. 4 is perpendicular to the cross-sectional direction of FIG. On the one hand, the edge gap 321 serves as a release hole for releasing the sacrificial material filled in the first cavity. On the other hand, the edge of the piezoelectric layer 32 can be exposed to the air, thereby effectively suppressing transverse waves. Specifically, the projections of the air side gap 321, the first overhead portion and the second overhead portion on the piezoelectric layer 32 are staggered, and enclose a closed ring or a ring with a gap. The air gap 321 may be one or more through holes distributed on the outer circumference of the piezoelectric layer above the first cavity 121 and outside the effective resonance region, or the air gap 321 may be an unclosed ring structure. The structure has a certain length.

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

Example 2

As shown in FIG. 5, this embodiment provides another thin film bulk acoustic resonator structure. The difference between this embodiment and Embodiment 1 is that the first dielectric layer 95 is located between the first substrate 1 and the piezoelectric layer 32. And the first dielectric layer 95 surrounds the first electrode 31 and forms a closed ring; the second dielectric layer 96 is located on the piezoelectric layer 32 in the ineffective resonance zone and is separated from the second electrode 33. The second dielectric layer 96 and the first The two electrode lead structures 5 are continuously connected, and the second dielectric layer 96 and the second lead structure 5 surround the second electrode 33. The first dielectric layer 95 is in contact with the outer circumference of the first electrode 31 or has a gap, and the surfaces of the first dielectric layer 95 and the first electrode 31 facing the piezoelectric layer 32 are flush. The upper surface and the lower surface of the piezoelectric layer 32 are both flat surfaces, covering the first cavity 121 and extending to the outside of the first cavity 121.

Specifically, the film bulk acoustic resonator of this embodiment includes: a first dielectric layer 95 is provided between the first substrate 1 and the piezoelectric layer 32. The first dielectric layer 95 is located in the ineffective resonance zone, surrounds the first electrode 31 and forms a closed ring.

In this embodiment, the first dielectric layer 95 is closely attached to the first electrode 31 in the horizontal direction of the plane where the piezoelectric layer 32 is located, that is, the first dielectric layer 95 is in contact with the outer periphery of the first electrode 31. Further, the surfaces of the first dielectric layer 95 and the first electrode 31 facing the piezoelectric layer 32 are flush, which can effectively ensure the overall flatness of the piezoelectric layer 32 during the formation process and improve the performance of the piezoelectric layer 32.

In another embodiment, the first dielectric layer 95 is disconnected from the first electrode 31, that is, there is a gap between the first dielectric layer 95 and the first electrode 31. The existence of a gap between the first dielectric layer 95 and the first electrode 31 ensures that the sidewalls of the first electrode 31 are all exposed in the cavity, which reduces the surface wave loss on the surface of the first electrode 31 and improves the performance of the resonator.

In this embodiment, the first electrode extraction structure 4 is located between the first dielectric layer 95 and the first substrate 1, the second electrode extraction structure 5 is located on the piezoelectric layer 32, the first electrode extraction structure 4 and the second electrode For the specific structure and materials of the lead structure 5, please refer to Embodiment 1, which will not be repeated here.

6, the present embodiment further includes a second dielectric layer 96, the second dielectric layer 96 is located on the piezoelectric layer 32 in the ineffective resonance region, and is separated from the second electrode 33, the second dielectric layer 96 and the second electrode The lead structure 5 is continuously connected, and the second dielectric layer 96 and the second lead structure surround the second electrode 33.

Specifically, the second dielectric layer 96 is located above the piezoelectric layer 32 and surrounds the second electrode 33 and is separated from each other to form a gap between the edge of the effective resonance region and the edge of the second electrode 33. The second overhead portion 51 makes the second electrode 33 The edge sidewalls of the edge wall are completely exposed to the air. The second dielectric layer 96 is continuously connected with the second overlapping portion 52 and forms a ring shape. The second dielectric layer 96 extends on the piezoelectric layer 32 outside the edge of the effective resonance region. The material of the second dielectric layer 96 can be the same as that of the first dielectric layer 95, and can be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc. kind.

The second dielectric layer 96 and the first dielectric layer 95 can effectively improve the overall mechanical strength of the resonator, and the arrangement of the second dielectric layer 96 can also improve the bonding effect when the top cover 8 is subsequently formed.

Referring to FIG. 6, the present embodiment can also form first protrusions 6 and second protrusions 7 on the surface edges of the first electrode 31 and the second electrode 33, respectively. The structure and materials of the first protrusions 6 and the second protrusions 7 Please refer to Embodiment 1, which will not be repeated here.

In this embodiment, an air gap 321 that penetrates the piezoelectric layer 32 and communicates with the first cavity 121 may also be provided at the edge area of the effective resonance region. For the structure of the air gap 321, please refer to Embodiment 1. 1E, this embodiment may also include a top cover 8, the top cover 8 is arranged on the piezoelectric laminate structure, the top cover 8 has a second cavity 811, the second cavity 811 is located above the first cavity 121 , And the second electrode 33 is located in the second cavity 811. For the specific structure and material of the top cover 8, please refer to Embodiment 1.

Example 3

Figures 7 to 18 are structural schematic diagrams corresponding to the corresponding steps of the method of manufacturing a thin film bulk acoustic resonator of this embodiment. The method is used to manufacture the thin film bulk acoustic resonator of Embodiment 1. The following will refer to Figures 7 to 18 in detail The manufacturing method of a thin film bulk acoustic resonator provided in this embodiment is described.

Referring to Fig. 7, a temporary substrate 90 is provided, and a second electrode layer 33', a piezoelectric layer 32, and a first electrode 31 are sequentially formed on the temporary substrate, and the first electrode 31 is located in an effective resonance region.

Referring to Fig. 7, the second electrode layer 33' is first deposited on the temporary substrate 90, then the piezoelectric layer is deposited on the second electrode layer, and finally the first electrode layer 31' is deposited on the piezoelectric layer. The piezoelectric layer 32 is formed on the flat second electrode layer 33' through the deposition process, which can make the piezoelectric layer 32 have a better crystal lattice orientation, improve the piezoelectric characteristics of the piezoelectric layer 32, and thereby improve the overall resonator. performance.

8, after the first electrode layer 31' is formed, the first electrode layer 31' is patterned to form the first electrode 31, and the boundary of the first electrode 31 only exists within the boundary of the effective resonance region.

8 and 9, a first electrode lead-out structure 4 is formed. The first electrode lead-out structure 4 is connected to the edge of the first electrode 31 and extends to the ineffective area as the first signal connection end. The edge of the effective resonant area is connected to the piezoelectric layer 32 A first gap 43 is enclosed with the first electrode 31.

Specifically, the method for forming the first electrode extraction structure 4 includes: forming a first sacrificial protrusion 92 on the edge of the first electrode 31; forming a first conductive layer to cover the piezoelectric layer and the first sacrificial protrusion; The conductive layer forms the first electrode lead-out structure 4; the first sacrificial protrusion 92 is removed to form a first gap.

Specifically: first, a first sacrificial protruding material layer is formed on the piezoelectric layer 32, the first sacrificial protruding material layer covers the first electrode 31 and the piezoelectric layer 32; the first sacrificial protruding material layer is patterned, in the first A first sacrificial protrusion 92 is formed outside the edge of the electrode 31 and close to the sidewall of the first electrode. Alternatively, the first sacrificial protrusion 92 may also be located on the first electrode 31 and extend to the piezoelectric layer 32.

The material of the first electrode extraction structure 4 is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, and copper.

After the first electrode extraction structure 4 is formed, the method further includes: removing the first sacrificial protrusion 92 to form the first gap 43.

At this time, the first electrode lead-out structure 4 includes a first overhead portion 41 enclosing a first gap 43 and a first overlapping portion 42 extending to the ineffective area. The first overlapping portion 42 serves as a first signal connection end. The overhead portion 41 and the first overlapping portion 42 are electrically connected; the first overlapping portion 42 surrounds the outer circumference of the first electrode 31, and the first overhead portion 41 surrounds the outer circumference of the first electrode 31.

Please refer to Embodiment 1 for the specific structure of the first overhead portion 41 and the first overlapping portion 42.

10, a first substrate 1 including a first cavity 121 is formed on the piezoelectric layer 32. The first substrate 1 covers a part of the first electrode extraction structure 4, and the first electrode 31 is located in the first cavity 121. Within the boundaries of the area.

In this embodiment, the method of forming the first substrate 1 including the first cavity 121 is as follows: forming the support layer 12 on the piezoelectric layer 32, and forming the first cavity 121 in the support layer 12; The base 11 is bonded to the supporting layer 12; the supporting layer 12 and the base 11 constitute the first substrate 1.

Specifically, first, the support layer 12 is formed by chemical vapor deposition or physical vapor deposition. The support layer covers the piezoelectric layer 32, the first electrode 31 and the first electrode extraction structure 4, and the material of the support layer 12 is, for example, silicon dioxide. One or several combinations of (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3) and aluminum nitride.

Then, a first cavity 121 is formed in the support layer 12, and the first electrode 31 is located in the first cavity 121; in this embodiment, the first cavity 121 can be formed by etching the support layer 12 through an etching process. The cavity 121 penetrates the supporting layer 12, and the substrate 11 is bonded to the supporting layer 12 so that the substrate 11 covers the first cavity 121.

In this embodiment, the bonding of the substrate 11 and the support layer 12 can be achieved by thermocompression bonding, or the bonding of the substrate 11 and the support layer 12 can be achieved by dry film bonding. For the material of the base 11, refer to the temporary substrate 90, which will not be repeated here. Bonding the first substrate 1 including the first cavity 121 to the piezoelectric layer 32 through a bonding process can ensure that the piezoelectric laminate structure will not be deformed during the process of forming the first cavity 121 , To ensure the structural stability of the piezoelectric stack.

In this embodiment, before bonding the first substrate to the piezoelectric layer, it further includes releasing the first sacrificial protrusion 92 to form the first gap 43. The first gap exposes the edge of the first electrode, and when the transverse wave is transmitted to the edge of the first electrode, reflection occurs at the air interface, which suppresses the loss of the transverse wave, thereby increasing the Q value of the resonator.

In this embodiment, a bonding process is adopted. Therefore, before the first substrate is bonded to the piezoelectric layer, the first sacrificial protrusion 92 can be released first. In the embodiment where the piezoelectric layer is a complete film layer, it can be Avoid drilling holes in the piezoelectric layer to release the first sacrificial protrusion 92, ensuring the integrity of the piezoelectric layer, improving the structural strength of the piezoelectric layer, and improving the yield of the resonator.

Referring to FIG. 11, the temporary substrate 90 is removed.

12, the second electrode layer 33' is patterned to form the second electrode 33; the effective resonance region includes the first electrode 31, the piezoelectric layer 32, and the second electrode 33 overlapping each other in a direction perpendicular to the surface of the piezoelectric layer 32 Area; first, the second electrode layer 33' is patterned to form a second electrode 33, and the second electrode 33 only reserves the effective resonance area; the method of patterning the second electrode layer 33' to form the second electrode refers to the first electrode layer 31' The method of forming the first electrode will not be repeated here.

The shape of the second electrode 33 and the first electrode 31 may be the same or different. In this embodiment, the shape of the second electrode 33 and the first electrode 31 are the same, and they are arranged opposite to each other.

12-13, a second electrode lead-out structure 5 is formed. The edge of the second electrode lead-out structure 5 connected to the second electrode 33 extends to the ineffective area as a second signal connection end, and is connected to the piezoelectric layer 32 at the edge of the effective resonant area. And the second electrode 33 to form a second gap 53.

When one of the first signal connection terminal and the second signal connection terminal is a signal input terminal, the other is a signal output terminal.

Specifically, the method of forming the second electrode extraction structure includes: forming a second sacrificial protrusion 93 on the edge of the second electrode; forming a second conductive layer to cover the piezoelectric layer and the second sacrificial protrusion 93; and patterning the second conductive layer , The second electrode lead-out structure 5 is formed; the second sacrificial protrusion 93 is removed, and the second gap 53 is formed.

In this embodiment, the second electrode lead-out structure 5 includes a second overhead portion 51 covering the second sacrificial protrusion 108a and a second overlapping portion 52 on the surface of the piezoelectric layer 32. The second overlapping portion 1052 extends to the first At the periphery of the cavity 121, the second overhead portion and the second overlap portion are electrically connected. The material of the second electrode extraction structure 5 is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, and copper. The material of the first electrode extraction structure 4 may be the same as or different from the material of the second electrode extraction structure 5.

Referring to FIG. 13, after forming the second electrode extraction structure 5, it further includes: removing the second sacrificial protrusion 93 to form a second gap 53.

Specifically, the second sacrificial protrusion 93 is released through a dry etching process or a wet etching process, so that a second gap 53 is formed between the second overhead portion 51 and the edge of the second electrode 33 and the surface of the piezoelectric layer 32. After the second electrode extraction structure is formed, the edges on both sides of the second sacrificial protrusions are exposed to the air, and the second sacrificial protrusions can be directly released; the second sacrificial protrusions 93 can also be released in subsequent steps (which can be released with The following first sacrificial layer is removed at the same time), which will not be described here. The second gap 53 can expose the entire edge of the second electrode 33 to the air, and when the transverse wave is transmitted to the edge of the second electrode 33, it is reflected at the air interface, which can effectively suppress the loss of the transverse wave, thereby increasing the Q value of the resonator.

The second electrode lead-out structure 5 includes a second overhead portion 51 enclosing a second gap 53 and a second overlapping portion 52 extending to the ineffective area. The second overlapping portion 52 is electrically connected to the second external signal terminal. The portion 51 is electrically connected to the second overlapping portion 52; the second overlapping portion 52 surrounds the outer circumference of the second electrode 33; the second overhead portion 1062 surrounds the outer circumference of the second electrode 33.

In this embodiment, the projections of the first electrode extraction structure 4 and the second electrode extraction structure 5 on the surface of the piezoelectric layer 32 are staggered. It can prevent the coupling effect due to potential floating and prevent the parasitic effect.

The projections of the first gap 43 and the second gap 53 on the piezoelectric layer 32 form a closed ring or a ring with gaps.

In this embodiment, the first electrode 31 and the first electrode extraction structure 4 are formed on the first surface of the piezoelectric layer 32, and then the second electrode 33 and the second electrode extraction structure 5 are formed on the second surface of the piezoelectric layer 32. The process of electrode patterning on both sides of the piezoelectric layer avoids the etching of the piezoelectric layer during the electrode formation process, ensures the integrity and flatness of the piezoelectric layer 32, and reduces the impact on the piezoelectric layer, thereby Improve the performance of the resonator, and this method is compatible with the main process of the resonator, and the process is simple.

In this embodiment, referring to FIG. 14, after the second electrode extraction structure 5 is formed, the method further includes: etching the piezoelectric layer 32 at the edge of the effective resonance region to form a piezoelectric layer 32 that penetrates the piezoelectric layer 32 and communicates with the first cavity 121 The air gap 321.

An air gap 321 that penetrates the piezoelectric layer and communicates with the first cavity 121 is provided at the edge area of the effective resonance region, so that a part of the edge of the piezoelectric layer 32 is exposed to the air, thereby effectively suppressing transverse waves. Refer to Embodiment 1 for the structure and function of the air gap 321.

In other embodiments, the piezoelectric layer 32 may also be a complete film layer without being etched. Such an arrangement can increase the structural strength of the resonator.

In this embodiment, it further includes: forming first protrusions 6 on the first electrode, and the first protrusions 6 are distributed along the edge of the first electrode 31.

And/or, second protrusions 7 are formed on the second electrode 33, and the second protrusions 7 are distributed along the edge of the second electrode 33.

Referring to FIG. 15, on the basis of FIG. 9, after forming the first electrode lead-out structure 4, first protrusions 6 are formed on the first electrode 31. The first protrusions 6 are distributed along the edge of the first electrode and are connected to the first electrode. The projection of an overhead portion 41 on the surface of the piezoelectric layer 32 forms a closed ring or a gap with a gap.

The projections of the first protrusion 6 and the first gap 43 on the surface of the piezoelectric layer enclose a closed ring or a gap with a gap.

After the second electrode extraction structure 5 is formed, second protrusions 7 are formed on the second electrode 33. The second protrusions 7 are distributed along the edge of the second electrode and are aligned with the projection of the second overhead portion 51 on the surface of the piezoelectric layer 32. Enclosed in a closed ring or with gaps.

The projection of the second protrusion and the second gap on the surface of the piezoelectric layer encloses a closed or gap ring.

It should be noted that the first protrusion 6 may also be formed after the first electrode 31 and before the first electrode extraction structure 4, or when the first electrode extraction structure 4 is formed by etching, the first protrusion may also be formed by etching. 6. The first bump and the first electrode lead out of the same material. It should be noted that the second protrusion 7 may also be formed after the second electrode 33 and before the second electrode extraction structure 5, or, when the second electrode extraction structure 5 is formed by etching, the second protrusion may also be formed by etching. Starting from 7, the second bump and the second electrode lead out of the same material.

In this embodiment, the method of forming the first bump 6 is as follows: after forming the first electrode lead-out structure 4, before bonding the first substrate 11: in the piezoelectric layer 32, the first electrode 31 and the first electrode lead-out structure A mask layer (not shown) is formed on 4, and the mask layer exposes part of the first electrode 31 at the edge;

A first bump material layer is formed, the first bump material layer covers the mask layer and the exposed first electrode 31; the mask layer is removed to form the first bump 6, the first bump 6 is a continuous whole or includes A plurality of first sub-bumps are intermittently arranged.

The method for forming the second bump 7 is similar to the method for forming the first bump 6, and is also formed by a mask layer, by forming a mask on the piezoelectric layer 32, the first electrode 31, and the first electrode lead-out structure 4. Layer, the mask layer can expose part of the first electrode 31 at the edge, and then the first protrusion 6 is formed by patterning, which can ensure that the piezoelectric layer 32, the first electrode 31 and the first electrode lead-out structure 4 are not etched. The integrity of the piezoelectric layer 32, the first electrode 31 and the first electrode lead-out structure 4 is ensured, and the overall structure of the molded resonator is further ensured to be stable.

Please refer to Embodiment 1 for the structure, material and function of the first protrusion 6 and the second protrusion 7.

Referring to FIG. 16, in other embodiments of the present invention, based on FIG. 9, it may further include: after forming the first electrode 31, forming a first dielectric layer 95 and a first electrode on the piezoelectric layer 32 in the invalid region 31 are separated from each other; the first dielectric layer 95 and the first overlapping portion 42 are continuously connected.

In another embodiment, referring to FIG. 16, it further includes: after forming the second electrode 33, a second dielectric layer 96 is formed on the piezoelectric layer 32 in the ineffective area, separated from the second electrode 33, and the second dielectric layer 96 is continuously connected with the second overlapping part.

In other embodiments, the first dielectric layer 95 may also be formed after the first electrode lead-out structure 4 is formed, and the second dielectric layer 96 may also be formed after the second electrode lead-out structure 5 is formed. In this embodiment, the first dielectric layer 95 and the second dielectric layer 121b are separated from the first electrode 31 and the second electrode 33 to form a gap. By exposing the first electrode 31 or the second electrode 33 to the air, Effectively suppress the loss of transverse waves.

Please refer to Embodiment 1 for the specific effects of forming the first dielectric layer 95 and the second dielectric layer 96 on the upper and lower surfaces of the piezoelectric layer 32 respectively.

Referring to FIG. 17, in another embodiment, based on FIG. 9, after forming the first electrode lead-out structure 4, the first protrusion 6 and the first dielectric layer 95 may also be formed; and after the second electrode lead-out structure is formed After structure 5, the second protrusions 7 and the second dielectric layer 96 may be formed. Specifically, the first protrusions 6 and the first dielectric layer 95 may be formed at the same time or at different times. When the material of the dielectric layer 95 is the same, the first protrusion 6 and the first dielectric layer 95 can be formed at the same time. Similarly, the second protrusion 7 and the second dielectric layer 96 can be formed at the same time or at different times. When the materials of 7 and the second dielectric layer 96 are the same, they can also be formed at the same time. It should be understood that when the first protrusion 6, the second protrusion 7, the first dielectric layer 95, and the second dielectric layer 96 are included at the same time, it can be more beneficial to suppress transverse wave leakage, improve the mechanical strength, and improve the effect of the top cover bonding. . In other embodiments, only at least one of the first protrusion 6 and the second protrusion 7 and at least one of the first dielectric layer 95 and the second dielectric layer 96 may be formed, which will not be repeated here.

Referring to FIG. 18, in this embodiment, based on FIG. 13, it further includes forming a top cover on the piezoelectric stack. The top cover includes a second cavity 811, and the second electrode 33 is located in the second cavity 811.

In one embodiment, the method of forming the top cover includes: providing a second substrate and forming a bonding layer 81 on the second substrate 82; patterning the bonding layer 81 to form a second cavity 811; The electrical laminate structure is bonded. Alternatively, a second cavity is formed in the second substrate, and the second substrate shown is bonded to the piezoelectric laminate structure. In another embodiment, the specific method for forming the top cover on the piezoelectric stack may also be: forming a sacrificial layer above the first cavity 121 to cover the second electrode; forming a bonding layer 81 to cover the sacrificial layer, the second electrode The overhead portion 51 and the piezoelectric layer 32; a release hole is formed on the top of the bonding layer 81; the sacrificial layer is released to form a second cavity 811; and the second substrate 82 is bonded on the bonding layer 81.

In one embodiment, the sacrificial layer and the unreleased second sacrificial protrusion 93 are released through the release hole to form the second cavity 811 and the second void 53 respectively.

19-22 are structural schematic diagrams corresponding to the corresponding steps of another method for manufacturing a thin-film bulk acoustic resonator. The difference between this method and the method of the above-mentioned embodiment is that a sacrificial layer is used to form the first cavity.

Specifically, FIG. 19 is based on FIG. 9, after forming the first electrode extraction structure 4, the first electrode extraction structure 4 covering the first electrode 31 and the first electrode extraction structure 4 located at the boundary of the effective resonance region is formed. A sacrificial layer 91; forming a first substrate 1 covering the first sacrificial layer 91 and the piezoelectric layer (refer to FIG. 20); removing the temporary substrate 90 (refer to FIG. 21); patterning the second electrode layer 33' to form the first After the second electrode 33 is formed, the second sacrificial protrusion and the second electrode lead-out structure 5 are formed; after the second electrode lead-out structure 5 is formed, the first sacrificial layer 91 is removed.

Specifically, the first sacrificial layer 91 is formed to cover the first electrode 31 and the first electrode extraction structure 4 located at the boundary of the effective resonance region. Then, the support layer 12 and the substrate 11 are sequentially formed. The method of forming the first sacrificial layer 91 may be different depending on the material, and the forming process of the first sacrificial layer 91 includes a deposition process or a spin coating process. By using the first sacrificial layer 91 to form the first cavity, it can be supported during the formation of the first substrate 1 to prevent the piezoelectric laminated structure 3 from being compressed and deformed due to uneven force, and subsequent In the reverse process, the piezoelectric layer is supported to ensure the flatness of the piezoelectric laminated structure 3. After the second electrode lead-out structure is formed, the first sacrificial layer 1 is removed. For example, the first sacrificial layer 91 can be combined with the first sacrificial protrusion 92 and the second sacrificial protrusion 93 by forming a release hole in a subsequent step. Remove together.

Example 4

FIG. 23 to FIG. 29 are structural schematic diagrams corresponding to the corresponding steps of the method of manufacturing a thin film bulk acoustic resonator of this embodiment, and the method is used to manufacture the filter structure of Embodiment 2.

Referring to FIG. 23, a first substrate 1 is provided, a first cavity 121 is formed in the first substrate 1, a first sacrificial layer 91 and a first electrode extraction structure 4, and the first sacrificial layer 91 fills the first cavity 121, The upper surface of the first sacrificial layer 91 is flush with the upper surface of the first substrate 1, and the first electrode extraction structure 4 is located in the first substrate 1 and the first sacrificial layer 91.

In this embodiment, the first substrate 1 includes a base 11 and a supporting layer 12, the supporting layer 12 is deposited on the base 11, and the materials of the base 11 and the supporting layer 12 refer to the first embodiment. The first cavity 121 may be formed by etching the support layer 12 of the first substrate 1 through an etching process. In other embodiments, the first substrate 1 may be an integral structure, the first substrate 1 is a complete layer, and the first cavity 121 is formed by etching the first substrate 1.

After the first cavity 121 is formed, the material of the first sacrificial layer 91 may be filled into the first cavity 121 by chemical vapor deposition or physical vapor deposition. After the deposition is completed, the top surface of the filled first sacrificial layer 91 is flush with the top surface of the first substrate 1 through a planarization process, and the planarization process can select chemical mechanical polishing. Through the process of filling the first sacrificial layer 91 and making the top surface of the first sacrificial layer 91 flush with the top surface of the first substrate 1, the first electrode lead-out structure can be formed on a flat surface, and can be used for subsequent steps. The formed first electrode lead-out structure 4, piezoelectric laminate structure, and second electrode lead-out structure provide support to ensure the structural integrity and the stability of the overall structure of the molded resonator.

Continuing to refer to FIG. 23, a first electrode extraction structure 4 is formed in the supporting layer 12 and the first sacrificial layer 91.

In this embodiment, the method for forming the first electrode lead-out structure 4 includes: SA1: forming a first groove on the upper surface of the first substrate 1 and the first sacrificial layer 91, the first groove extending from the edge of the effective resonance region To the periphery of the first cavity 121;

SA2: A second groove is formed in the edge region of the first sacrificial layer 91 corresponding to the effective resonance region, the second groove is connected to the first groove, and the depth of the second groove is greater than the depth of the first groove. The method of forming the first groove and the second groove is similar to the method of forming the first cavity 121, and dry etching or a combination of wet etching and dry etching can be selected. SA3: A first conductive layer is formed to cover the inner surfaces of the first groove and the second groove.

SA4: Remove the first conductive layer other than the first groove and the second groove through a patterning or planarization process to form a first electrode lead-out structure 4, the first electrode lead-out structure 4 covers the sidewall and bottom of the second groove , And fill the first groove, the first electrode lead-out structure 4 in the second groove is the first overhead portion 41, and the first electrode lead-out structure 4 in the first groove is the first overlap portion 42.

In this embodiment, the first electrode lead-out structure 4 includes a first overhead portion 41 located at the boundary of the effective resonance region and a first overlapping portion 42 located on the surface of the support layer 12.

In another embodiment, the method of forming the first cavity 121 and the first electrode lead-out structure 4 may also be: SB1: forming a first groove and a first groove in the first substrate 1 through an etching process Connected second groove, wherein the depth of the first groove along the thickness direction of the first substrate 1 is greater than the depth of the second groove, and in the direction from the center to the outside of the first substrate 1, the second groove Located outside the first groove; SB2: A first conductive layer is formed on the first substrate 1, in the first groove and in the second groove, so that the first conductive layer fills the second groove and covers the first The sidewalls and bottom of the groove; SB3: the first conductive layer on the first substrate 1 is removed by an etching process or a planarization process; wherein, the first conductive layer in the first groove and the second groove is the first conductive layer The electrode extraction structure 4, the first electrode extraction structure 4 covers the sidewall and bottom of the first groove, and fills the second groove; the first electrode extraction structure 4 in the first groove is the first overhead portion 41, the second The first electrode lead-out structure 4 in the groove is the first lap 42; SB4: the first substrate 1 is etched to form a first cavity 121, and the first cavity 121 exposes a part of the first electrode lead-out structure 4. An overlap portion 42 extends to the periphery of the first cavity 121; SB5: a first sacrificial layer 91 is formed in the first cavity 121, fills the first cavity 121 and covers the first overhead portion 41, and undergoes a planarization process For subsequent process steps.

Wherein, the first electrode lead-out structure is formed through the planarization process, which can ensure that the first dielectric layer and the first electrode to be formed subsequently are formed on a flat surface.

Continuing to refer to FIG. 23, after forming the first electrode lead-out structure 4, this embodiment further includes: forming a second sacrificial layer 94 to cover the first overhead portion 41 and fill the second groove.

For the structure and material of the first electrode lead-out structure 4, refer to the aforementioned first embodiment, which will not be repeated here.

Referring to FIGS. 24-26, a first dielectric layer 95, a first electrode 31, a piezoelectric layer 32, and a second electrode 33 are formed on the first substrate 1, wherein the first electrode 31 is located at the boundary of the first cavity 121 Inside, the first dielectric layer 95 is located between the piezoelectric layer 32 and the first substrate 1. The first dielectric layer 95 surrounds the first electrode 31 and forms a closed ring. The first electrode 31, the piezoelectric layer 32 and the second electrode 33. The area overlapping each other in the direction perpendicular to the surface of the piezoelectric layer 32 is the effective resonant area; the edge of the first electrode lead-out structure 4 connecting the first electrode 31 extends to the ineffective resonant area as the first signal connection end. The boundary and the piezoelectric laminate structure enclose a first gap 43.

24, the method of forming the first electrode 31 and the first dielectric layer 95 includes: first, forming a first electrode layer, covering the first sacrificial layer 91, the second sacrificial layer 94, the first electrode extraction structure 4 and the support layer 12. ; Then, the first electrode layer is patterned to form the first electrode 31, the first electrode 31 is located within the area enclosed by the first cavity 121, and the edge of the first electrode 31 and the first overhead of the first electrode lead structure 4 Part 41 is connected; after that, a first dielectric layer 95 is formed to cover the first electrode 31, the second sacrificial layer 94 and the first substrate 1; finally, the first dielectric layer 95 above the first electrode 31 is removed by mechanical grinding, The surface of the first electrode 31 is exposed.

Wherein, the first dielectric layer 95 is continuously connected with the first electrode 31 and surrounds the first electrode 31 to form a closed ring.

In another embodiment, the first dielectric layer 95 may be formed first to cover the first sacrificial layer 91, the second sacrificial layer 94, the first electrode lead-out structure 4 and the support layer 12; the first dielectric layer 95 may be patterned and removed. The first dielectric layer 95 above the first sacrificial layer 91 and the surface of the first sacrificial layer 91 is exposed; then a first electrode layer is formed to cover the first dielectric layer 95, the second sacrificial layer 94 and the first sacrificial layer 91; Mechanical grinding removes the first electrode layer above the first dielectric layer 95 to form the first electrode 31. The first electrode 31 is located within the area enclosed by the first cavity 121, and the edge of the first electrode 31 and the first electrode lead out The first overhead part 41 of the structure 4 is connected.

In this embodiment, the surfaces of the first electrode 31 and the first dielectric layer 95 are adjusted by forming the first dielectric layer 95 so that they are flush, thereby ensuring that the piezoelectric layer formed on the surface of the first electrode 31 and the first dielectric layer 95 32. At the same time, the first dielectric layer 95 is located in the ineffective area and surrounds the first electrode 31, so that the surface of the piezoelectric layer 32 in the ineffective area is flat, so that the piezoelectric layer 32 has good piezoelectric performance and provides piezoelectric The stability of the laminated structure improves the performance of the resonance region.

Referring to FIG. 25, in another embodiment, there may be a gap between the formed first dielectric layer 95 and the first electrode 31, and a sacrificial material may be formed between the first dielectric layer 95 and the first electrode 31 and then The removal method in the process flow creates a gap between the first dielectric layer 95 and the first electrode 31, which ensures that all the sidewalls of the first electrode 31 are exposed in the cavity, and reduces the surface wave loss on the surface of the first electrode 31 , Improve the performance of the resonator.

Further, after the first dielectric layer 95 is formed, the surfaces of the first dielectric layer 95 and the first electrode 31 need to be flattened, so that the upper surface of the first dielectric layer 95 and the upper surface of the first electrode 31 are flush with each other. It is ensured that the subsequently formed piezoelectric layer 32 can be formed on a flat surface, so as to ensure the flatness of the entire piezoelectric layer 32, so that the piezoelectric layer has good piezoelectric performance, thereby improving the performance of the resonator.

Referring to FIG. 26, a piezoelectric layer 32 and a second electrode layer are sequentially formed on the first dielectric layer 95 and the first electrode 31, and the second electrode 33 is patterned on the second electrode layer.

In this embodiment, the second electrode 33 and the first electrode 31 have the same shape and area, and both are polygons, for example, any two non-parallel polygons. The first electrode 31 and the second electrode 33 are arranged opposite to each other on both sides of the piezoelectric layer 32. , And the projections of the first electrode 31 and the second electrode 33 on the surface of the piezoelectric layer 32 completely overlap. Since the piezoelectric layer 32 is formed on a flat surface, the piezoelectric layer 32 is a flat and complete layer.

27 and 28, a second electrode lead-out structure 5 is formed. The edge of the second electrode lead-out structure 5 connected to the second electrode 33 extends to the ineffective resonant region as the second signal connection end, and the edge of the effective resonant region is connected to the piezoelectric layer 32 and the second electrode 33 form a second gap 53.

The method of forming the second electrode lead-out structure 5 includes: after the second electrode 33 is formed, a first sacrificial protrusion 92 is formed at the edge of the effective resonance region, and the top of the first sacrificial protrusion 92 is higher than the surface of the second electrode 33.

Specifically, the material of the first sacrificial protrusion 92 can be used to cover the second electrode 33 and the piezoelectric layer 32 by chemical vapor deposition or physical vapor deposition. The material of the first sacrificial protrusion 92 can refer to the material of the first sacrificial layer 91 . After the deposition is completed, the first sacrificial protrusion 92 is formed through a patterning process. After that, a second conductive layer is formed on the second electrode 33 and the piezoelectric layer 32, the second conductive layer is patterned, and the second electrode extraction structure 5 is formed. . For the structure and material of the second electrode lead-out structure 5, refer to the aforementioned first embodiment, which will not be repeated here.

Further, in this embodiment, the first electrode lead-out structure 4 and the second electrode lead-out structure 5 have no overlapping regions in the direction perpendicular to the piezoelectric layer 32 after the patterning process, which can avoid partial high-frequency coupling and improve FBAR The Q value.

Referring to FIG. 28, the first sacrificial layer 91 is removed.

The step of removing the first sacrificial layer 91 includes forming at least one release hole in the piezoelectric layer 32 at the edge of the first cavity 121 in the non-effective resonance region before or after forming the second electrode extraction structure 5. The material of the first sacrificial layer 91 and the second sacrificial layer 94 is removed through the release hole, and the first sacrificial protrusion 92 is removed at the same time. After the first sacrificial layer 91 is released, the first cavity 121 is formed, and after the second sacrificial layer 94 is released A first gap 43 is formed, and after the first sacrificial protrusion 92 is released, a second gap 53 is formed.

In this embodiment, referring to FIG. 29, before forming the first electrode 31, after forming the first sacrificial layer 91, a third groove is formed on the upper surface of the first sacrificial layer 91, and the third groove is located in the edge region of the effective resonance region. Use the first protrusion material to fill the third groove to form the first protrusion 6; wherein, the third groove is formed on the upper surface of the first sacrificial layer 91 by etching through an etching process, and then sequentially through a deposition process and etching The first protrusion 6 is formed by an etching process; and, after the second electrode 33 is formed, the second protrusion 7 is formed on the second electrode 33 through a deposition process and an etching process in sequence.

For the structure, positional relationship, material and beneficial effects of the first protrusion 6 and the second protrusion 7 in this embodiment, refer to the foregoing embodiments 1 and 2, which will not be repeated here.

There are many methods for forming the first protrusion 6 and the second protrusion 7 in the present invention. The classification of the material for forming the protrusion mainly includes the following two forms: The first form: on the basis of FIG. 23, after forming the first protrusion 6 Before the electrode 31, after forming the first electrode lead-out structure 4, a third groove is formed on the upper surface of the first sacrificial layer 91, a structural material layer is formed on the first sacrificial layer 91 and the third groove, and the third groove is filled, In the case where the structural material layer is thick, the etching process is performed on the structural material layer to form the first protrusion 6 and the first electrode 31 at the same time.

On the basis of FIG. 27 or FIG. 28, a structural material layer is formed on the piezoelectric layer 32, and an etching process is performed on the structural material layer to simultaneously form the second electrode 33 and the second protrusion 7.

The second form: On the basis of FIG. 23, before forming the first electrode 31, after forming the first electrode lead-out structure 4, a third groove is formed on the upper surface of the first sacrificial layer 91, and a third groove is formed on the third groove. The protrusion material layer is filled with the third groove, and the first protrusion 6 is formed by performing an etching process on the protrusion material layer. After that, the first electrode 31 is formed on the first sacrificial layer 91 and the first protrusion 6.

On the basis of FIG. 26, after the second electrode 33 is formed, a bump material layer is formed on the second electrode 33, and an etching process is performed on the bump material layer to form the second bump 7.

In other embodiments, the second protrusion 7 may also be formed after the second electrode extraction structure 5 is formed; or, after the second electrode 33 is formed, but before the second electrode extraction structure 5 is formed. Moreover, when the material of the second bump 7 and the second electrode lead-out structure 5 are the same, the second bump 7 can also be formed by etching when the second electrode lead-out structure 5 is formed by etching. At this time, it is directly formed by a single deposition process. The material layer is subjected to an etching process to simultaneously form the second protrusion 7 and the second electrode extraction structure 5.

Continuing to refer to FIG. 29, it may also include: before or after forming the second electrode extraction structure 5, forming a second dielectric layer 96 on the piezoelectric layer 32, the second dielectric layer 96 is located at the periphery of the effective resonance region and in the effective resonance region The edge and the edge of the second electrode 33 are separated from each other to form a gap. The second dielectric layer 96 and the second overlap portion 52 are continuously connected to form a ring shape and surround the second electrode 33. The method for forming the second dielectric layer 96 and For the material, refer to the first dielectric layer 95, which will not be repeated here. The arrangement of the second dielectric layer 96 in conjunction with the first dielectric layer 95 and the second dielectric layer 96 can effectively ensure the flatness of the entire piezoelectric stack and improve the overall mechanical strength of the resonator. The arrangement of the second dielectric layer 96 can also The bonding effect can be improved when the top cover 8 is subsequently formed.

In the method of manufacturing the thin film bulk acoustic resonator of this embodiment, before or after the second electrode extraction structure 5 is formed, it may further include: etching the edge region of the effective resonance region to form a penetrating piezoelectric layer 32 and communicating with the first sacrifice The air gap of the layer 91, the projection of the air gap on the piezoelectric layer 32 and the projections of the first gap 43 and the second gap 53 on the piezoelectric layer 32 are staggered, and enclose a continuous or discontinuous ring. The cooperation of the air edge gap with the first gap 43 and the second gap 53 can jointly achieve the effect of suppressing transverse waves.

Referring to FIG. 30, in this embodiment, after the second electrode extraction structure 5 is formed, and the first sacrificial layer 91 is removed, a top cover 8 may be formed on the piezoelectric stack, and the top cover 8 includes a second cavity 811 , The second electrode 33 and the second overhead portion 51 are located in the second cavity 811.

The method of forming the top cover 8 refers to Embodiment 3, which will not be repeated here.

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

The foregoing description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes or modifications made by a person of ordinary skill in the field of the present invention based on the foregoing disclosure shall fall within the protection scope of the claims.

Claims

A thin film bulk acoustic wave resonator, which is characterized by comprising: a first substrate in which a first cavity is provided; a piezoelectric laminate structure, including first electrodes stacked in sequence from bottom to top, The piezoelectric layer and the second electrode, the edges of the first electrode and the second electrode are both located within the boundary of the area enclosed by the first cavity, and the effective resonance region includes the first electrode, the piezoelectric layer and The area where the second electrode overlaps each other in the direction perpendicular to the surface of the piezoelectric layer; the first electrode lead-out structure connects the edge of the first electrode and extends to the ineffective resonance area as the first signal connection end. The edge of the resonance region and the piezoelectric laminate structure enclose a first gap; the second electrode lead-out structure is connected to the edge of the second electrode and extends to the ineffective resonance region as a second signal connection end. The edge of the effective resonance region and the piezoelectric laminate structure enclose a second gap.
The thin film bulk acoustic resonator according to claim 1, wherein the projections of the first electrode extraction structure and the second electrode extraction structure on the surface of the piezoelectric layer are staggered; and/or, the first The gap and the projection of the second gap on the piezoelectric layer form a closed ring or a ring with a gap.
The thin-film bulk acoustic resonator according to claim 1, wherein the first electrode extraction structure comprises: a first overhead part enclosing the first gap, connecting the first overhead part and extending to the The first overlap portion of the ineffective resonance region, the first overlap portion serves as the first signal connection end; and/or, the second electrode lead-out structure includes: a second gap surrounding the second gap An overhead portion, a second overlapping portion connected to the second overhead portion and extending to the ineffective resonance zone, and the second overlapping portion serves as the second signal connection end.
The thin film bulk acoustic resonator according to claim 3, wherein the piezoelectric layer covers the first cavity, and the surface of the first lap portion facing the piezoelectric layer is facing the first electrode. The surface of the piezoelectric layer is flush; and/or the surface of the second lap portion facing the piezoelectric layer is flush with the surface of the second electrode facing the piezoelectric layer.
The thin-film bulk acoustic resonator according to claim 3, wherein the first overlapping portion surrounds the outer circumference of the first electrode, or the first overlapping portion is disposed on the outer periphery of the first electrode. Part of the outer circumference; the first overhead portion surrounds the outer circumference of the first electrode; the second overlap portion surrounds the outer circumference of the second electrode, or the second overlap portion is disposed on the second Part of the outer circumference of the electrode; the second overhead part surrounds the outer circumference of the second electrode.
The thin film bulk acoustic resonator according to claim 1, further comprising a first protrusion and/or a second protrusion, the first protrusion being located on the first electrode and along the effective resonance The projections of the first protrusion and the first overhead portion on the surface of the piezoelectric layer are closed or ring with gaps; the second protrusion is located on the second electrode and Distributed along the boundary of the effective resonance region, the projection of the second protrusion and the second overhead portion on the surface of the piezoelectric layer is a closed ring or a ring with a gap.
The thin film bulk acoustic resonator according to claim 1, further comprising a first dielectric layer and/or a second dielectric layer; the first dielectric layer is located between the first substrate and the piezoelectric layer In between, the first dielectric layer is located in the ineffective resonance zone and is separated from the first electrode, and the first dielectric layer and the first overlap portion surround the first electrode; Two dielectric layers are located on the piezoelectric layer, the second dielectric layer is located in the ineffective resonance zone and is separated from the second electrode, and the second dielectric layer and the second overlapping portion surround the Mentioned second electrode.
The thin film bulk acoustic resonator according to claim 1, further comprising a first dielectric layer and/or a second dielectric layer; the first dielectric layer is located between the first substrate and the piezoelectric layer And the first dielectric layer surrounds the first electrode and forms a closed ring; the first dielectric layer is in contact with the outer periphery of the first electrode or has a gap, and the first dielectric layer and The surface of the first electrode facing the piezoelectric layer is flush; the second dielectric layer is located on the piezoelectric layer in the ineffective resonance zone and is separated from the second electrode. The two dielectric layers and the second electrode lead-out structure are continuously connected, and the second dielectric layer and the second lead-out structure surround the second electrode.
The thin film bulk acoustic resonator according to claim 1, wherein an air gap that penetrates the piezoelectric layer and communicates with the first cavity is further provided at the edge of the effective resonance region.
A method for manufacturing a thin-film bulk acoustic wave resonator is characterized in that it comprises: providing a temporary substrate; sequentially forming a second electrode layer, a piezoelectric layer and a first electrode on the temporary substrate, and the first electrode is located at Effective resonant area; forming a first electrode lead-out structure, the first electrode lead-out structure is connected to the edge of the first electrode and extends to the ineffective area as the first signal connection end, at the edge of the effective resonant area and the piezoelectric layer and The first electrode encloses a first gap; a first substrate including a first cavity is formed on the piezoelectric layer, the first substrate covers a portion of the first electrode extraction structure, and the first electrode is located Within the boundary of the region enclosed by the first cavity; removing the temporary substrate; patterning the second electrode layer to form a second electrode; the effective resonance region includes the first electrode, a piezoelectric layer, and The area where the second electrode overlaps each other in the direction perpendicular to the surface of the piezoelectric layer; a second electrode extraction structure is formed, and the second electrode extraction structure is connected to the edge of the second electrode and extends to the ineffective area as a second signal connection At the edge of the effective resonance zone, a second gap is enclosed with the piezoelectric layer and the second electrode.
The method for manufacturing a thin film bulk acoustic resonator according to claim 10, wherein the projections of the first electrode extraction structure and the second electrode extraction structure on the surface of the piezoelectric layer are staggered; and/or; The projections of the first gap and the second gap on the piezoelectric layer enclose a closed ring or a ring with a gap.
The method for manufacturing a thin film bulk acoustic resonator according to claim 10, wherein the first electrode lead-out structure comprises a first overhead part enclosing the first gap and a first overlap extending to the ineffective area Portion, the first overlapping portion serves as the first signal connection end, the first overhead portion and the first overlapping portion are electrically connected; the first overlapping portion surrounds the first electrode Outer circumference, the first overhead portion surrounds the outer circumference of the first electrode; and/or, the second electrode lead-out structure includes a second overhead portion that encloses the second gap and a second overhead portion that extends to the ineffective area An overlap portion, the second overlap portion is electrically connected with a second external signal terminal, the second overhead portion is electrically connected with the second overlap portion; the second overlap portion surrounds the second The outer circumference of the electrode; the second overhead portion surrounds the outer circumference of the second electrode.
The method of manufacturing a thin film bulk acoustic resonator according to claim 10, wherein the piezoelectric layer is a complete film layer; or, after the second electrode extraction structure is formed, further comprising: etching the The piezoelectric layer at the edge of the effective resonance region forms an air gap that penetrates the piezoelectric layer and communicates with the first cavity; the air gap, the first gap, and the second gap are in The projections of the piezoelectric layers are staggered with each other and form a closed ring or a ring with gaps.
The method for manufacturing a thin film bulk acoustic resonator according to claim 10, wherein the method of forming the first electrode extraction structure comprises: forming a first sacrificial protrusion on the edge of the first electrode, and the first sacrificial The protrusions are located on the first electrode and the sidewall of the first electrode, or the first sacrificial protrusions are located on the sidewall of the first electrode; a first conductive layer is formed to cover the piezoelectric layer and the First sacrificial protrusion; patterning the first conductive layer to form the first electrode lead-out structure; removing the first sacrificial protrusion to form the first gap.
The method of manufacturing a thin-film bulk acoustic resonator according to claim 10, wherein the method of forming the second electrode lead-out structure comprises: forming a second sacrificial protrusion on the edge of the second electrode, and the second sacrificial The protrusions are located on the second electrode and the sidewalls of the second electrode, or the second sacrificial protrusions are located on the sidewalls of the second electrode; a second conductive layer is formed to cover the piezoelectric layer and the Second sacrificial protrusions; patterning the second conductive layer to form the second electrode extraction structure; removing the second sacrificial protrusions to form a second gap.
The method of manufacturing a thin film bulk acoustic resonator according to claim 10, further comprising: forming a first protrusion on the first electrode, the first protrusion being along an edge of the first electrode Distribution; when the first electrode extraction structure is formed by etching, the first protrusion is also formed by etching, and the first protrusion is made of the same material as the first electrode extraction structure; or, when the first electrode extraction structure is formed The first protrusion is formed after an electrode lead-out structure; or, the first protrusion is formed after the first electrode is formed and before the first electrode lead-out structure; the first protrusion and the first gap are in the place The projection of the surface of the piezoelectric layer encloses a closed or gap ring.
The method of manufacturing a thin-film bulk acoustic resonator according to claim 10, further comprising: forming a second protrusion on the second electrode, the second protrusion being along an edge of the second electrode Distribution; when the second electrode extraction structure is formed by etching, the second protrusions are also formed by etching, and the second protrusions are made of the same material as the second electrode extraction structure; or, when the first electrode extraction structure is formed The second protrusion is formed after the two electrode extraction structure; or, the second protrusion is formed after the second electrode is formed and before the second electrode extraction structure; the second protrusion and the second gap are in the place The projection of the surface of the piezoelectric layer encloses a closed or gap ring.
The method of manufacturing a thin-film bulk acoustic resonator according to claim 10, further comprising: after forming the first electrode, forming a first dielectric layer on the piezoelectric layer in the ineffective region to interact with the first electrode. Separate; the first dielectric layer is continuously connected to the first overlap portion; and/or, after the second electrode is formed, a second dielectric layer is formed on the piezoelectric layer in the ineffective region, and the second dielectric layer is connected to the second The electrodes are separated from each other, and the second dielectric layer is continuously connected with the second overlapping portion.
The method for manufacturing a thin film bulk acoustic resonator according to claim 10, wherein the forming a first substrate including a first cavity on the piezoelectric layer comprises: providing a first substrate; Forming the first cavity in the first substrate; bonding the first substrate and the piezoelectric layer so that the first substrate covers a portion of the first electrode lead-out structure, the The first electrode is located within the boundary of the region enclosed by the first cavity; or, a first sacrificial layer covering the first electrode and the first electrode extraction structure located at the boundary of the effective resonance region is formed to form a cover The first sacrificial layer and the first substrate of the piezoelectric layer; after forming the second electrode extraction structure, the first sacrificial layer is removed.
A method for manufacturing a thin film bulk acoustic wave resonator is characterized in that it comprises: providing a first substrate; forming a first cavity, a first sacrificial layer and a first electrode extraction structure in the first substrate, and The first sacrificial layer fills the first cavity, the upper surface of the first sacrificial layer is flush with the upper surface of the first substrate, and the first electrode extraction structure is located between the first substrate and the first substrate. A sacrificial layer; forming a first dielectric layer, a first electrode, a piezoelectric layer and a second electrode on the first substrate, wherein the first electrode is located in the boundary of the first cavity, so The first dielectric layer is located between the piezoelectric layer and the first substrate, the first dielectric layer surrounds the first electrode and forms a closed ring, the first electrode, the piezoelectric layer and the first substrate The area where the two electrodes overlap each other in the direction perpendicular to the surface of the piezoelectric layer is the effective resonance area; The boundary of the effective resonance region and the piezoelectric laminate structure enclose a first gap; a second electrode extraction structure is formed, and the second electrode extraction structure is connected to the edge of the second electrode and extends to the ineffective resonance region as the first gap. Two signal connection ends, forming a second gap with the piezoelectric layer and the second electrode at the edge of the effective resonance region; removing the first sacrificial layer.