Film bulk acoustic resonator and preparation method thereof

Abstract

The invention discloses a film bulk acoustic resonator and a preparation method thereof. The transducer comprises a substrate, a transducer stacking structure and a temperature compensation layer, the top electrode layer comprises a first electrode layer and a second electrode layer; the second electrode layer is located on one side of the first electrode layer away from the piezoelectric layer; the first electrode layer comprises a through groove which penetrates through the first electrode layer; the temperature compensation layer comprises a first branch part and a second branch part; the first branch part is arranged in the through groove, so that a concave structure is formed on the surface of the transducer stacking structure; and the second subsection is arranged between the first electrode layer and the second electrode layer, so that a convex structure is formed on the surface of the transducer stacking structure. According to the technical scheme, unnecessary vibration or damping can be avoided, and energy loss and parasitic modes caused by other non-resonance are reduced, so that the frequency temperature drift of the film bulk acoustic resonator is reduced, the Q value of the film bulk acoustic resonator is improved, and the parasitic modes are reduced.

Description

Technical Field

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

[0002] With the ultra-high-speed development of wireless communication technology and the multi-functionalization of communication terminals, higher performance requirements are put forward for frequency devices operating in the radio frequency band. Compared with traditional dielectric ceramic filters and surface acoustic wave filters, filters based on thin film bulk acoustic wave resonators can work well in the range of several hundred MHz to 6 - 7 GHz, and have the advantages of high frequency, low loss, low temperature drift characteristics, steep filter skirts, and extremely high Q values, operating frequencies, sensitivities, resolutions, and power capacity that can be tolerated. Therefore, thin film bulk acoustic wave resonators occupy most of the application fields of wireless communication.

[0003] With the change of operating temperature, the resonant frequency of the thin film bulk acoustic wave resonator will shift. Since there are many frequency bands in modern communication systems and the interval between adjacent channels is small, the frequency drift caused by temperature may affect the signal transmission of adjacent frequency bands, thereby causing signal interference. Therefore, ensuring that the thin film bulk acoustic wave resonator has excellent temperature stability is crucial for avoiding communication interference.

[0004] The existing methods for reducing the frequency drift of thin film bulk acoustic wave resonators mainly involve adding temperature compensation materials to the thin film bulk acoustic wave resonator structure. Usually, a whole layer of temperature compensation material is added to the thin film bulk acoustic wave resonator. However, the existing technical means will cause a significant decline in the performance of the thin film bulk acoustic wave resonator, easily generate parasitic modes, and seriously affect signal transmission. Summary of the Invention

[0005] The present invention provides a thin film bulk acoustic wave resonator and a preparation method thereof to solve the problem that the thin film bulk acoustic wave resonator in the prior art easily generates parasitic modes.

[0006] According to one aspect of the present invention, a thin film bulk acoustic wave resonator is provided, including: a substrate, a transducer stack structure, and a temperature compensation layer;

[0007] The transducer stack structure is located on one side of the substrate; the transducer stack structure includes a bottom electrode layer, a piezoelectric layer, and a top electrode layer which are stacked; the top electrode layer includes a first electrode layer and a second electrode layer; the second electrode layer is located on the side of the first electrode layer away from the piezoelectric layer;

[0008] The first electrode layer includes a through groove that penetrates the first electrode layer; the temperature compensation layer includes a first part and a second part; the first part is arranged in the through groove to form a concave structure on the surface of the transducer stack structure; the second part is arranged between the first electrode layer and the second electrode layer to form a convex structure on the surface of the transducer stack structure;

[0009] The transducer stack structure includes a working area; in the thickness direction of the thin film bulk acoustic wave resonator, the projection of the working area on the plane where the substrate is located covers the projection of the temperature compensation layer on the plane where the substrate is located; the temperature-elastic coefficient of the temperature compensation layer is greater than zero, and the temperature-elastic coefficient of the transducer stack structure is less than zero.

[0010] Optionally, in the thickness direction of the thin film bulk acoustic wave resonator, the projection of the second part on the plane where the substrate is located surrounds the projection of the first part on the plane where the substrate is located and the projection of the second part on the plane where the substrate is located is connected to the projection of the first part on the plane where the substrate is located.

[0011] Optionally, in the thickness direction of the thin film bulk acoustic wave resonator, the projection of the first part on the plane where the substrate is located surrounds the projection of the second part on the plane where the substrate is located and the projection of the first part on the plane where the substrate is located is connected to the projection of the second part on the plane where the substrate is located.

[0012] Optionally, the second part includes a first sub-part and a second sub-part;

[0013] In the thickness direction of the thin film bulk acoustic wave resonator, the projection of the first part on the plane where the substrate is located surrounds the projection of the first sub-part on the plane where the substrate is located, and the projection of the second sub-part on the plane where the substrate is located surrounds the projection of the first part on the plane where the substrate is located;

[0014] The projection of the first part on the plane where the substrate is located is connected to the projection of the first sub-part on the plane where the substrate is located, and the projection of the first part on the plane where the substrate is located is connected to the projection of the second sub-part on the plane where the substrate is located.

[0015] Optionally, the first part includes a third sub-part and a fourth sub-part; the thickness of the third sub-part is different from the thickness of the fourth sub-part;

[0016] In the thickness direction of the thin film bulk acoustic wave resonator, the projection of the fourth sub-part on the plane where the substrate is located surrounds

[0017] the projection of the third sub-part on the plane where the substrate is located, and the projection of the second part on the plane where the substrate is located surrounds the projection of the fourth sub-part on the plane where the substrate is located;

[0018] The projection of the fourth sub-part on the plane where the substrate is located is connected to the projection of the third sub-part on the plane where the substrate is located, and the projection of the fourth sub-part on the plane where the substrate is located is connected to the projection of the second part on the plane where the substrate is located.

[0019] Optionally, the first part and the second part are not connected to each other.

[0020] Optionally, the thickness of the first part is the same as the thickness of the second part.

[0021] Optionally, it further includes an airfoil and an air bridge formed by a second electrode layer and a piezoelectric layer;

[0022] Along the thickness direction of the thin film bulk acoustic wave resonator, the projection of the airfoil on the plane of the substrate does not overlap with the projection of the temperature compensation layer on the plane of the substrate; the projection of the air bridge on the plane of the substrate does not overlap with the projection of the temperature compensation layer on the plane of the substrate.

[0023] According to another aspect of the present invention, there is provided a method for manufacturing a thin film bulk acoustic wave resonator, which is used to manufacture a thin film bulk acoustic wave resonator; the manufacturing method includes:

[0024] Providing a substrate;

[0025] Sequentially preparing a bottom electrode layer, a piezoelectric layer, and a first electrode layer on one side of the substrate;

[0026] Etching the first electrode layer to form a through groove;

[0027] Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer;

[0028] Preparing a second electrode layer on the side of the temperature compensation layer away from the first electrode layer;

[0029] Wherein, the temperature compensation layer includes a first sub - portion and a second sub - portion; the first sub - portion is disposed in the through groove to form a concave structure on the surface of the transducer stack structure; the second sub - portion is disposed between the first electrode layer and the second electrode layer to form a convex structure on the surface of the transducer stack structure.

[0030] Optionally, preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer includes:

[0031] Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer;

[0032] Etching the first sub - portion of the temperature compensation layer to form a third sub - portion and a fourth sub - portion with different thicknesses.

[0033] Optionally, etching the first electrode layer to form a through groove includes:

[0034] Etching the first electrode layer to form a through groove and a groove;

[0035] Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer includes:

[0036] Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer so that the temperature compensation layer fills into the through groove and the groove;

[0037] After preparing the second electrode layer on the side of the temperature compensation layer away from the first electrode layer, it further includes:

[0038] Etch the transducer stack structure to form a release channel;

[0039] Introduce an etching medium into the release channel to form a cavity in the substrate, and introduce the etching medium into the groove to etch the temperature compensation layer in the groove to form an air wing and an air bridge.

[0040] In the technical solution of the present invention, by providing a through groove in the first electrode layer, the first part of the temperature compensation layer is arranged in the through groove, and the second part is arranged between the first electrode layer and the second electrode layer, so that a convex structure and a concave structure are formed on the surface of the transducer stack structure. Furthermore, during the operation of the thin film bulk acoustic wave resonator, unnecessary vibrations or damping can be avoided, energy loss and parasitic modes caused by other non-resonances are reduced, thereby reducing the frequency temperature drift of the thin film bulk acoustic wave resonator while increasing the Q value of the thin film bulk acoustic wave resonator and reducing parasitic modes.

[0041] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 is a schematic structural diagram of a first thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0044] Figure 2 is a top view schematic diagram of a first thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0045] Figure 3 is a schematic structural diagram of a second thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0046] Figure 4 is a top view schematic diagram of a second thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0047] Figure 5 is a schematic structural diagram of a third thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0048] Figure 6 is a top view schematic diagram of a third thin film bulk acoustic wave resonator provided according to an embodiment of the present invention;

[0049] Figure 7 It is a schematic structural diagram of the fourth thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0050] Figure 8 It is a top view schematic diagram of the fourth thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0051] Figure 9 It is a schematic structural diagram of the fifth thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0052] Figure 10 It is a schematic structural diagram of the sixth thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0053] Figure 11 It is a flowchart of the preparation method of the first thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0054] Figure 12 It is a corresponding structural diagram of the preparation method of the first thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0055] Figure 13 It is a flowchart of the preparation method of the second thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0056] Figure 14 It is a corresponding structural diagram of the preparation method of the second thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0057] Figure 15 It is a flowchart of the preparation method of the third thin film bulk acoustic resonator provided according to an embodiment of the present invention;

[0058] Figure 16 It is a corresponding structural diagram of the preparation method of the third thin film bulk acoustic resonator provided according to an embodiment of the present invention. Detailed implementation manners

[0059] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0061] Figure 1 is a schematic structural diagram of a first thin film bulk acoustic resonator provided according to an embodiment of the present invention, Figure 2 is a top view schematic diagram of a first thin film bulk acoustic resonator provided according to an embodiment of the present invention. Combining Figure 1 and Figure 2 as shown, the thin film bulk acoustic resonator includes:

[0062] a substrate 1, a transducer stack structure 2, and a temperature compensation layer 3;

[0063] The transducer stack structure 2 is located on one side of the substrate 1; the transducer stack structure 2 includes a bottom electrode layer 21, a piezoelectric layer 22, and a top electrode layer 23 which are stacked; the top electrode layer 23 includes a first electrode layer 231 and a second electrode layer 232; the second electrode layer 232 is located on the side of the first electrode layer 231 away from the piezoelectric layer 22;

[0064] The first electrode layer 231 includes a through groove 4, and the through groove 4 penetrates through the first electrode layer 231; the temperature compensation layer 3 includes a first part 31 and a second part 32; the first part 31 is disposed in the through groove 4 so as to form a concave structure 310 on the surface of the transducer stack structure 2; the second part 32 is disposed between the first electrode layer 231 and the second electrode layer 232 so as to form a convex structure 320 on the surface of the transducer stack structure 2;

[0065] The transducer stack structure 2 includes a working area; along the thickness direction of the thin film bulk acoustic resonator, the projection of the working area on the plane where the substrate 1 is located covers the projection of the temperature compensation layer 3 on the plane where the substrate 1 is located; the temperature-elastic coefficient of the temperature compensation layer 3 is greater than zero, and the temperature-elastic coefficient of the transducer stack structure 2 is less than zero.

[0066] Among them, the substrate 1 can be the base of the thin-film bulk acoustic wave resonator, and a silicon material substrate 1 can be selected during the actual preparation process. The transducer stack structure 2 includes a bottom electrode layer 21, a piezoelectric layer 22, and a top electrode layer 23. The bottom electrode layer 21 is disposed on one side of the substrate 1. The piezoelectric layer 22 is disposed on the side of the bottom electrode layer 21 away from the substrate 1. The top electrode layer 23 is disposed on the side of the piezoelectric layer 22 away from the bottom electrode layer 21. During the operation of the thin-film bulk acoustic wave resonator, electrical energy is converted into acoustic waves through the inverse piezoelectric effect to form resonance. The working area of the transducer stack structure 2 can be the overlapping area of the bottom electrode layer 21, the piezoelectric layer 22, and the top electrode layer 23. This part is the main resonance area, and this working area can convert electrical energy into acoustic waves and generate oscillations.

[0067] In some embodiments, a cavity 5 is provided in the substrate 1, which can enhance the reflection performance of acoustic waves.

[0068] Among them, the temperature compensation layer 3 can be made of a material with a positive temperature coefficient. For example, SiO2, F-doped SiO2, B-doped SiO2, etc. The temperature-elastic coefficient can be used to characterize the change in Young's modulus affected by temperature. The temperature-elastic coefficient of the temperature compensation layer 3 is a positive temperature-elastic coefficient, while the temperature-elastic coefficient in the transducer stack structure 2 is a negative temperature-elastic coefficient. The temperature compensation layer 3 is disposed in the top electrode layer 23. The temperature compensation layer 3 can compensate for the negative temperature-elastic coefficient of the transducer stack structure 2 through its own elastic change, thereby reducing the influence of temperature on the performance of the thin-film bulk acoustic wave resonator and improving the communication anti-interference performance of the thin-film bulk acoustic wave resonator.

[0069] Since the performance of the transducer stack structure 2 will decline due to the setting of the whole-layer temperature compensation material, which in turn affects the performance of the thin-film bulk acoustic wave resonator, in the embodiment of the present invention, when the temperature compensation layer 3 is provided in the top electrode layer 23, the through-groove 4 is etched so that there are convex structures 320 and concave structures 310 on the surface of the transducer stack structure 2. The performance of the bulk acoustic wave resonator can be adjusted by the setting of the convex structures 320. Among them, since the temperature compensation layer 3 is provided in the top electrode layer 23, the top electrode layer 23 is prepared in two steps. First, the first electrode layer 231 is prepared. The through-groove 4 is etched in the first electrode layer 231. The through-groove 4 penetrates the first electrode layer 231. The position of the through-groove 4 should be within the working area of the transducer stack structure 2 to ensure the effectiveness of the suppression. After the through-groove 4 is etched, the temperature compensation layer 3 is continuously deposited. The temperature compensation layer 3 covers the through-groove 4 and the surface of the first electrode layer 231. Since the through-groove 4 causes convex and concave parts on the surface of the first electrode layer 231, after the temperature compensation layer 3 is provided, there are also convex and concave parts on the surface of the temperature compensation layer 3. Then, after the second electrode layer 232 is prepared subsequently, there is a concave structure 310 at the corresponding position of the first through-groove on the surface of the second electrode layer 232, and there are convex structures 320 at the corresponding positions of other temperature compensation layers 3, while reducing the frequency temperature drift of the thin-film bulk acoustic wave resonator and improving the performance of the thin-film bulk acoustic wave resonator.

[0070] It can be understood that the temperature compensation layer 3 in the embodiment of the present invention is provided with a first part 31 and a second part 32. The first part 31 is provided in the through-groove 4. Due to the existence of the through-groove 4, a concave structure 310 is formed on the surface of the transducer stack structure 2. The second part 32 is provided on the surface of the first electrode layer 231, and a convex structure 320 is formed on the surface of the transducer stack structure 2. The convex structure 320 and the concave structure 310 are formed because of the different distribution positions of the temperature compensation layer 3, so that the convex structure 320 and the concave structure 310 can be formed under the normal subsequent preparation of the second electrode layer 232.

[0071] It can be understood that the purpose of providing the temperature compensation layer 3 in the top electrode layer 23 is to ensure the formation effect of the convex structure 320 and the concave structure 310 without adding extra steps.

[0072] Exemplarily, first, the bottom electrode layer 21 and the piezoelectric layer 22 in the transducer stack structure 2 are prepared on one side of the substrate 1. After the piezoelectric layer 22 is deposited, the first electrode layer 231 is deposited. After the first electrode layer 231 is prepared, a through-hole 4 is etched at the corresponding position of the first electrode layer 231. After the through-hole 4 is prepared, the temperature compensation layer 3 is grown. The first part 31 of the temperature compensation layer 3 fills the through-hole 4, and the second part 32 covers the surface of part of the first electrode layer 231. After the temperature compensation layer 3 is prepared, the second electrode layer 232 is deposited, so that a concave structure 310 is formed at the corresponding part of the first part 31, and a convex structure 320 is formed at the corresponding part of the second part 32.

[0073] It can be understood that the thicknesses of the first part 31 and the second part 32 can be the same or different, and can be controlled according to performance requirements, so that the performance of the bulk acoustic wave resonator can reach the best. Similarly, the first part 31 and the second part 32 can be formed in one preparation or in two preparations.

[0074] In some embodiments, a seed layer 130 is further provided between the bottom electrode layer 21 and the substrate 1 to improve the deposition quality of the subsequent piezoelectric layer 22.

[0075] The technical solution of the embodiment of the present invention, by providing a through-hole in the first electrode layer, and arranging the first part of the temperature compensation layer in the through-hole and the second part between the first electrode layer and the second electrode layer, makes a convex structure and a concave structure formed on the surface of the transducer stack structure. Furthermore, during the operation of the thin film bulk acoustic wave resonator, unnecessary vibrations or damping can be avoided, and the energy loss and parasitic modes caused by other non-resonances can be reduced. Thus, while reducing the frequency temperature drift of the thin film bulk acoustic wave resonator, the Q value of the thin film bulk acoustic wave resonator is increased, and the parasitic modes are reduced.

[0076] Optionally, continue to refer to Figure 1 and Figure 2 As shown, along the thickness direction of the thin film bulk acoustic wave resonator, the projection of the second part 32 on the plane of the substrate 1 surrounds the projection of the first part 31 on the plane of the substrate 1 and the projection of the second part 32 on the plane of the substrate 1 is connected to the projection of the first part 31 on the plane of the substrate 1.

[0077] Among them, the projection of the through-hole 4 on the plane of the substrate 1 can be set as a closed figure, and then the projection of the first part 31 on the plane of the substrate 1 is also a closed figure. To simplify the process flow, it can be set that the first part 31 and the second part 32 are prepared by the same process flow. Then, the first part 31 of the temperature compensation layer 3 fills the through-hole 4, and the second part 32 is arranged on the surface of the first electrode layer 231 due to the absence of the through-hole 4, so as to achieve the purpose of convex and concave.

[0078] In some embodiments, the thickness of the first part 31 is the same as that of the second part 32. In this way, the first part 31 and the second part 32 are prepared by the same process flow, which not only ensures the improved performance but also improves the preparation efficiency of the thin film bulk acoustic wave resonator.

[0079] In some embodiments, the first part 31 and the second part 32 can also be prepared in two times to form different thicknesses. The thicknesses of the first part 31 and the second part 32 can be determined according to the performance requirements, so that the performance of the bulk acoustic wave resonator can reach the best.

[0080] In the technical solution of the embodiment of the present invention, by setting the projection of the second part on the plane where the substrate is located to surround the projection of the first part on the plane where the substrate is located, the second part and the first part can be prepared in the same process flow, which not only ensures the improvement of the performance of the bulk acoustic wave resonator but also improves the preparation efficiency of the thin film bulk acoustic wave resonator.

[0081] Optionally, Figure 3 FIG. 12 is a schematic structural diagram of a second thin film bulk acoustic wave resonator provided according to an embodiment of the present invention. Figure 4 FIG. 13 is a top view schematic diagram of a second thin film bulk acoustic wave resonator provided according to an embodiment of the present invention. As shown in combination with Figure 3 and Figure 4 FIG. 14, along the thickness direction of the thin film bulk acoustic wave resonator, the projection of the first part 31 on the plane where the substrate 1 is located surrounds the projection of the second part 32 on the plane where the substrate 1 is located, and the projection of the first part 31 on the plane where the substrate 1 is located is connected to the projection of the second part 32 on the plane where the substrate 1 is located.

[0082] Wherein, the through groove 4 can also be set as an annular closed figure. When preparing the temperature compensation layer 3, due to the existence of the through groove 4, the projection of the first part 31 on the plane where the substrate 1 is located surrounds the projection of the second part 32 on the plane where the substrate 1 is located. In order to simplify the process flow, it can be set that the first part 31 and the second part 32 are prepared by the same process flow. Furthermore, the first part 31 of the temperature compensation layer 3 fills in the through groove 4, and since there is no through groove 4 for the second part 32, the temperature compensation layer 3 is arranged on the surface of the first electrode layer 231, thereby achieving the purpose of a depression around the middle protrusion.

[0083] In some embodiments, the first part 31 and the second part 32 can also be prepared in two times to form different thicknesses. The thicknesses of the first part 31 and the second part 32 can be determined according to the performance requirements, so that the performance of the bulk acoustic wave resonator can reach the best.

[0084] In the technical solution of the embodiment of the present invention, by setting the projection of the first part on the plane where the substrate is located to surround the projection of the second part on the plane where the substrate is located, the second part and the first part can be fabricated in the same process flow, ensuring the improvement of parasitic modes while increasing the fabrication efficiency of the thin film bulk acoustic wave resonator.

[0085] Optionally, Figure 5 FIG. 5 is a schematic structural diagram of a third thin film bulk acoustic wave resonator provided according to an embodiment of the present invention; Figure 6 FIG. 6 is a top view schematic diagram of a third thin film bulk acoustic wave resonator provided according to an embodiment of the present invention. As shown in FIGS. 5 and 6, the second part 32 includes a first sub - part 321 and a second sub - part 322; Figure 5 and Figure 6 As shown, the second part 32 includes a first sub - part 321 and a second sub - part 322;

[0086] Along the thickness direction of the thin film bulk acoustic wave resonator, the projection of the first part 31 on the plane where the substrate 1 is located surrounds the projection of the first sub - part 321 on the plane where the substrate 1 is located, and the projection of the second sub - part 322 on the plane where the substrate 1 is located surrounds the projection of the first part 31 on the plane where the substrate 1 is located;

[0087] The projection of the first part 31 on the plane where the substrate 1 is located is connected to the projection of the first sub - part 321 on the plane where the substrate 1 is located, and the projection of the first part 31 on the plane where the substrate 1 is located is connected to the projection of the second sub - part 322 on the plane where the substrate 1 is located.

[0088] Among them, it can also be set that the second part 32 includes a first sub - part 321 and a second sub - part 322, and the first sub - part 321 and the second sub - part 322 are distributed at different positions on the surface of the first electrode layer 231.

[0089] Specifically, the through - groove 4 is set as an annular closed structure. When preparing the temperature compensation layer 3, the first part 31 of the temperature compensation layer 3 is filled in the through - groove 4, the first sub - part 321 of the second part 32 is arranged in the area surrounded by the annular closed structure, and the second sub - part 322 surrounds the first part 31. Therefore, two convex structures 320 and a concave structure 310 are formed on the surface of the transducer stack structure 2. The convex structure 320 can also achieve the purpose of adjusting the performance of the bulk acoustic wave resonator, and at the same time, the concave structure 310 can also achieve the purpose of suppressing parasitic modes.

[0090] It can be understood that in the technical solution of the embodiment of the present invention, the first sub - part 321, the second sub - part 322, and the first part 31 can also be fabricated in the same process flow, thereby achieving the purpose of simplifying the process flow. Or the first part 31 and the second part 32 can be fabricated in two times to form different thicknesses, and the thicknesses of the first part 31 and the second part 32 can be determined according to the performance requirements, so that the performance of the bulk acoustic wave resonator can reach the best.

[0091] In some embodiments, the width of the first sub - part 31 may be set to be less than or equal to 10 μm, and the thickness may be set to be less than or equal to 300 nm; the width of the second sub - part 32 may be set to be less than or equal to 10 μm, and the thickness may be set to be less than or equal to 100 nm.

[0092] In the technical solution of the embodiment of the present invention, by setting that the second sub - part includes a first sub - sub - part and a second sub - sub - part, the projection of the first sub - part on the plane where the substrate is located surrounds the projection of the first sub - sub - part on the plane where the substrate is located, and the projection of the second sub - sub - part on the plane where the substrate is located surrounds the projection of the first sub - part on the plane where the substrate is located, the frequency - temperature drift of the thin - film bulk acoustic wave resonator is reduced while the Q - value of the thin - film bulk acoustic wave resonator is increased, and the parasitic mode is reduced.

[0093] Optionally, Figure 7 FIG. is a schematic structural diagram of a fourth thin - film bulk acoustic wave resonator provided according to an embodiment of the present invention. Figure 8 FIG. is a top - view schematic diagram of a fourth thin - film bulk acoustic wave resonator provided according to an embodiment of the present invention. Combining Figure 7 and Figure 8 as shown, the first sub - part 31 includes a third sub - sub - part 311 and a fourth sub - sub - part 312; the thickness of the third sub - sub - part 311 is different from the thickness of the fourth sub - sub - part 312.

[0094] Along the thickness direction of the thin - film bulk acoustic wave resonator, the projection of the fourth sub - sub - part 312 on the plane where the substrate 1 is located surrounds the projection of the third sub - sub - part 311 on the plane where the substrate 1 is located, and the projection of the second sub - part 32 on the plane where the substrate 1 is located surrounds the projection of the fourth sub - sub - part 312 on the plane where the substrate 1 is located.

[0095] The projection of the fourth sub - sub - part 312 on the plane where the substrate 1 is located is connected to the projection of the third sub - sub - part 311 on the plane where the substrate 1 is located, and the projection of the fourth sub - sub - part 312 on the plane where the substrate 1 is located is connected to the projection of the second sub - part 32 on the plane where the substrate 1 is located.

[0096] Wherein, it can also be set that the first sub - part 31 includes a third sub - sub - part 311 and a fourth sub - sub - part 312, and both the third sub - sub - part 311 and the fourth sub - sub - part 312 are arranged in the through - groove 4. Since the thickness of the third sub - sub - part 311 is different from the thickness of the fourth sub - sub - part 312, different degrees of concave structures 310 can also be formed on the surface of the transducer stack structure 2, thereby improving the parasitic mode.

[0097] Specifically, the through groove 4 is set as a closed structure. When preparing the temperature compensation layer 3, the first part 31 of the temperature compensation layer 3 is filled in the through groove 4, and the second part 32 is arranged around the first part 31. Then, the first part 31 is etched continuously to form a third sub - part 311 and a fourth sub - part 312 with different thicknesses. Therefore, two concave structures 310 and a convex structure 320 are formed on the surface of the transducer stack structure 2, which can also achieve the purpose of suppressing parasitic modes.

[0098] In some embodiments, considering reasons such as the etching rate in the process being difficult to control, the third sub - part 311 and the fourth sub - part 312 can be prepared separately, that is, first deposit and etch the third sub - part 311, then deposit and etch the fourth sub - part 312, or first deposit and etch the fourth sub - part 312, then deposit and etch the third sub - part 311.

[0099] Exemplarily, the thickness of the third sub - part 311 can be set to be greater than that of the fourth sub - part 312, and the thickness difference between the third sub - part 311 and the fourth sub - part 312 is less than 40 nm. Also, the width of the fourth sub - part 312 can be set to be less than or equal to 10 μm, and the width of the second part 32 can be set to be less than or equal to 10 μm, which can ensure the formation effect of the concave structure 310 without affecting the working performance of the bulk acoustic wave resonator.

[0100] It can be understood that the thickness of the second part 32 can be the same as or different from the thicknesses of the third sub - part 311 and the fourth sub - part 312, which can be set according to the actual performance requirements of the thin - film bulk acoustic wave resonator.

[0101] The technical solution of the embodiment of the present invention, by setting that the first part includes a third sub - part and a fourth sub - part; the thickness of the third sub - part is different from that of the fourth sub - part, two different concave structures are formed on the surface of the transducer stack structure, which can also achieve the purpose of reducing parasitic modes.

[0102] Optionally, Figure 9 is a schematic structural diagram of the fifth thin - film bulk acoustic wave resonator provided according to the embodiment of the present invention. As Figure 9 shown, the first part 31 and the second part 32 are not connected to each other.

[0103] Among them, the first part 31 and the second part 32 can also be set as non - connected structures. As Figure 9 shown, the first part 31 fills part of the through groove 4, the second part 32 is arranged on one side of the first electrode layer 231, and the second part 32 is not in contact with the first part 31. Then, after the second electrode layer 232 is prepared, there is a concave part 330 between the second part 32 and the first part 31, and this concave part 330 can also adjust the performance of the resonator.

[0104] In some embodiments, the size of the recessed portion 330 can be set according to the size requirements of the resonator, and the embodiments of the present invention do not limit this.

[0105] Optionally, Figure 10 FIG. 5 is a schematic structural diagram of a sixth thin film bulk acoustic resonator provided according to an embodiment of the present invention. As Figure 10 shown, it further includes an air wing 61 and an air bridge 62 formed by a second electrode layer 232 and a piezoelectric layer 22;

[0106] Along the thickness direction of the thin film bulk acoustic resonator, the projection of the air wing 61 on the plane where the substrate 1 is located does not overlap with the projection of the temperature compensation layer 3 on the plane where the substrate 1 is located; the projection of the air bridge 62 on the plane where the substrate 1 is located does not overlap with the projection of the temperature compensation layer 3 on the plane where the substrate 1 is located.

[0107] Among them, after the piezoelectric layer 22 is prepared, the air wing 61 and the air bridge 62 can be prepared by depositing a sacrificial layer on the piezoelectric layer 22; similarly, the sacrificial layer can also be deposited while depositing the temperature compensation layer 3.

[0108] Specifically, while etching the through groove 4 on the first electrode layer 231, a groove is etched, and the temperature compensation layer 3 is deposited on the through groove 4, the groove, and a part of the surface of the first electrode layer 231. After preparation, the second electrode layer 232 is continuously deposited. After the second electrode layer 232 is prepared, the material in the groove is etched by a corrosive medium, so as to form an air wing 61 and an air bridge 62 between the second electrode layer 232 and the piezoelectric layer 22.

[0109] It can be understood that the material of the sacrificial layer can be the same as or different from the material of the temperature compensation layer 3. When the material of the sacrificial layer is the same as the material of the temperature compensation layer 3, they can be prepared and formed in the same step, thereby simplifying the process flow.

[0110] The technical solution of the embodiment of the present invention, by providing an air wing and an air bridge between the second electrode layer and the piezoelectric layer, the projection of the air wing on the plane where the substrate is located does not overlap with the projection of the temperature compensation layer on the plane where the substrate is located; the projection of the air bridge on the plane where the substrate is located does not overlap with the projection of the temperature compensation layer on the plane where the substrate is located. Due to the existence of the air wing and the air bridge, transverse acoustic waves can be further reflected, energy leakage is reduced, and the Q value of the thin film bulk acoustic resonator is improved.

[0111] Based on the same inventive concept, Figure 11 FIG. 6 is a flowchart of a method for manufacturing a first thin film bulk acoustic resonator provided according to an embodiment of the present invention. Figure 12 FIG. 7 is a corresponding structural diagram of a method for manufacturing a first thin film bulk acoustic resonator provided according to an embodiment of the present invention. Combining Figure 11 and Figure 12As shown in the figure, an embodiment of the present invention provides a method for manufacturing a thin film bulk acoustic resonator, which is used to manufacture a thin film bulk acoustic resonator. The manufacturing method includes:

[0112] S10. Provide a substrate. As shown in step (a) of Figure 12 the figure.

[0113] Among them, the substrate 1 can be used as the base of the thin film bulk acoustic resonator. In the actual manufacturing process, a silicon material substrate 1 can be selected. In some embodiments, a sacrificial layer can also be filled in the substrate 1 to form a cavity structure subsequently.

[0114] S11. Sequentially prepare a bottom electrode layer, a piezoelectric layer, and a first electrode layer on one side of the substrate. As shown in step (b) of Figure 12 the figure.

[0115] Among them, the bottom electrode layer 21 is disposed on one side of the substrate 1, the piezoelectric layer 22 is disposed on the side of the bottom electrode layer 21 away from the substrate 1, and the first electrode layer 231 is disposed on the side of the piezoelectric layer 22 away from the bottom electrode layer 21.

[0116] S12. Etch the first electrode layer to form a through groove. As shown in step (c) of Figure 12 the figure.

[0117] Among them, the position of the through groove 4 should be within the working area of the transducer stack structure 2 to ensure the effectiveness of suppression.

[0118] S13. Prepare a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer. As shown in step (d) of Figure 12 the figure.

[0119] Among them, the temperature compensation layer 3 covers the surface of the through groove 4 and the first electrode layer 231. The temperature compensation layer 3 can be made of a material with a positive temperature-elastic coefficient. For example, SiO2, F-doped SiO2, B-doped SiO2, etc. The temperature-elastic coefficient of the temperature compensation layer 3 is a positive temperature-elastic coefficient, while the temperature-elastic coefficient in the transducer stack structure 2 is a negative temperature-elastic coefficient, thereby reducing the influence of temperature on the performance of the thin film bulk acoustic resonator.

[0120] Among them, since the through groove 4 causes the surface of the first electrode layer 231 to have convex and concave parts, after the temperature compensation layer 3 is provided, the surface of the temperature compensation layer 3 also has convex and concave parts.

[0121] S14. Prepare a second electrode layer on the side of the temperature compensation layer away from the first electrode layer. As shown in step (e) of Figure 12 the figure.

[0122] Among them, the temperature compensation layer 3 includes a first part 31 and a second part 32; the first part 31 is disposed in the through groove 4 so that a concave structure 310 is formed on the surface of the transducer stack structure 2; the second part 32 is disposed between the first electrode layer 231 and the second electrode layer 232 so that a convex structure 320 is formed on the surface of the transducer stack structure 2.

[0123] Among them, after the second electrode layer 232 is prepared, a concave structure 310 exists at the corresponding position of the first through groove on the surface of the second electrode layer 232, and a convex structure 320 exists at the corresponding positions of the other temperature compensation layers 3, while reducing the frequency temperature drift of the thin film bulk acoustic wave resonator and improving the performance of the thin film bulk acoustic wave resonator.

[0124] Exemplarily, first, the bottom electrode layer 21 and the piezoelectric layer 22 in the transducer stack structure 2 are prepared on one side of the substrate 1. The first electrode layer 231 is deposited on the basis of the piezoelectric layer 22. After the first electrode layer 231 is prepared, the first electrode layer 231 is etched at the corresponding position to form a through groove 4. After the through groove 4 is prepared, the temperature compensation layer 3 is grown. The first part 31 of the temperature compensation layer 3 is filled in the through groove 4, and the second part 32 covers a part of the surface of the first electrode layer 231. After the temperature compensation layer 3 is prepared, the second electrode layer 232 is deposited, so that a concave structure 310 is formed at the corresponding part of the first part 31, and a convex structure 320 is formed at the corresponding part of the second part 32.

[0125] In the technical solution of the embodiment of the present invention, by providing a through groove in the first electrode layer, the first part of the temperature compensation layer is disposed in the through groove, and the second part is disposed between the first electrode layer and the second electrode layer, so that a convex structure and a concave structure are formed on the surface of the transducer stack structure, and further, during the operation of the thin film bulk acoustic wave resonator, unnecessary vibrations or damping can be avoided, energy loss and parasitic modes caused by other non-resonances can be reduced, so that while reducing the frequency temperature drift of the thin film bulk acoustic wave resonator, the Q value of the thin film bulk acoustic wave resonator is increased, and the parasitic modes are reduced.

[0126] Based on the above embodiments, Figure 13 is a flowchart of a second method for manufacturing a thin film bulk acoustic wave resonator according to an embodiment of the present invention, Figure 14 is a corresponding structural diagram of a second method for manufacturing a thin film bulk acoustic wave resonator according to an embodiment of the present invention. Combining Figure 13 and Figure 14 as shown, the manufacturing method includes:

[0127] S20. Provide a substrate. As shown in step (f) of Figure 14 .

[0128] S21. Sequentially prepare a bottom electrode layer, a piezoelectric layer, and a first electrode layer on one side of the substrate. AsFigure 14 as shown in step (g).

[0129] S22. Etch the first electrode layer to form a through groove. As Figure 14 shown in step (h).

[0130] S23. Prepare a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer. As Figure 14 shown in step (i).

[0131] S24. Etch the first part of the temperature compensation layer to form a third sub - part and a fourth sub - part with different thicknesses. As Figure 14 shown in step (j).

[0132] In step S24, the third sub - part 311 and the fourth sub - part 312 can also be prepared separately, that is, first deposit and etch the third sub - part 311, then deposit and etch the fourth sub - part 312, or first deposit and etch the fourth sub - part 312, then deposit and etch the third sub - part 311.

[0133] Wherein, after the temperature compensation layer 3 is prepared, the first part 31 can be continuously etched to make the thicknesses of the third sub - part 311 and the fourth sub - part 312 of the first part 31 different, so as to form a concave structure 310 with different depths, achieving the purpose of reducing parasitic modes.

[0134] S25. Prepare a second electrode layer on the side of the temperature compensation layer away from the first electrode layer. As Figure 14 shown in step (k).

[0135] The technical solution of the embodiment of the present invention, by setting that the first part includes a third sub - part and a fourth sub - part; the thickness of the third sub - part is different from that of the fourth sub - part, makes two different concave structures formed on the surface of the transducer stack structure, and can also achieve the purpose of reducing parasitic modes.

[0136] On the basis of the above - mentioned embodiment, Figure 15 is a flowchart of the preparation method of the third thin - film bulk acoustic resonator provided by the embodiment of the present invention, Figure 16 is the corresponding structural diagram of the preparation method of the third thin - film bulk acoustic resonator provided by the embodiment of the present invention. Combining Figure 16 and Figure 15 as shown, the preparation method includes:[[]]

[0137] S30. Provide a substrate. As Figure 16 shown in step (l).

[0138] S31. Sequentially prepare a bottom electrode layer, a piezoelectric layer and a first electrode layer on one side of the substrate. As Figure 16 shown in step (m).

[0139] S32. Etch the first electrode layer to form a through groove and a recess, as shown in step (n) of Figure 16 .

[0140] S33. Prepare a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer, so that the temperature compensation layer fills into the through groove and the recess, as shown in step (o) of Figure 16 .

[0141] S34. Prepare a second electrode layer on the side of the temperature compensation layer away from the first electrode layer, as shown in step (p) of Figure 16 .

[0142] S35. Etch the transducer stack structure to form a release channel, as shown in step (q) of Figure 16 .

[0143] S36. Introduce a corrosion medium into the release channel to form a cavity in the substrate, and introduce a corrosion medium into the recess to corrode the temperature compensation layer in the recess, so as to form an air wing and an air bridge, as shown in step (r) of Figure 16 .

[0144] Among them, the structures of the air wing 61 and the air bridge 62 can play a role in improving the Q value. When etching the first electrode layer 231 to form the through groove 4, the recess 40 can be etched simultaneously. The recess 40 is between the piezoelectric layer 22 and the second electrode layer 232 and is used to form the air wing 61 and the air bridge 62. However, since the second electrode layer 232 is not prepared at this time, it is necessary to fill the recess 40 to prevent the second electrode layer 232 from being deposited in the recess 40. In the embodiment of the present invention, the temperature compensation layer 3 is reused as a sacrificial layer, so that the temperature compensation layer 3 also covers the recess 40, and the cavity 5 is also filled with the sacrificial layer. Then, when the corrosion medium corrodes the substrate 1, the temperature compensation layer 3 in the recess 40 can be released together, and then the air wing 61 and the air bridge 62 are formed. Similarly, the temperature compensation layer 3 and the sacrificial layer can also be prepared in two steps, because the thickness of the sacrificial layer affects the structural parameters of the air wing 61 and the air bridge 62, and different structural parameters of the air wing 61 and the air bridge 62 affect the performance of the resonator. Therefore, both the temperature compensation layer 3 and the sacrificial layer have corresponding thickness requirements.

[0145] Specifically, while etching the through groove 4 on the first electrode layer 231, the recess 40 is etched simultaneously. The temperature compensation layer 3 is deposited on the through groove 4, the recess 40 and a part of the surface of the first electrode layer 231. After preparation, the second electrode layer 232 is continuously deposited. After the second electrode layer 232 is prepared, the material in the recess 40 is corroded by the corrosion medium, and then the air wing 61 and the air bridge 62 are formed between the second electrode layer 232 and the piezoelectric layer 22.

[0146] In the technical solution of the embodiment of the present invention, a groove is etched and formed while etching the through groove in the first electrode layer, and the temperature compensation layer is also filled in the groove during the preparation of the temperature compensation layer. When the cavity is released subsequently, the temperature compensation layer in the groove is released together, thereby forming an air wing and an air bridge, which simplifies the process flow of the thin film bulk acoustic resonator. And due to the existence of the air wing and the air bridge, transverse acoustic waves can be further reflected, energy leakage can be reduced, and the Q value of the thin film bulk acoustic resonator can be improved.

[0147] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0148] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thin film bulk acoustic wave resonator, characterized in that, Comprising: A substrate, a transducer stack structure, and a temperature compensation layer; The transducer stack structure is located on one side of the substrate; The transducer stack structure includes a bottom electrode layer, a piezoelectric layer, and a top electrode layer which are stacked; the top electrode layer includes a first electrode layer and a second electrode layer; the second electrode layer is located on a side of the first electrode layer away from the piezoelectric layer; The first electrode layer includes a through groove that penetrates the first electrode layer; the temperature compensation layer includes a first part and a second part; the first part is disposed in the through groove to form a concave structure on the surface of the transducer stack structure; the second part is disposed between the first electrode layer and the second electrode layer to form a convex structure on the surface of the transducer stack structure; The transducer stack structure includes a working area; along the thickness direction of the thin film bulk acoustic resonator, a projection of the working area on a plane where the substrate is located covers a projection of the temperature compensation layer on the plane where the substrate is located; a temperature-elastic coefficient of the temperature compensation layer is greater than zero, and a temperature-elastic coefficient of the transducer stack structure is less than zero.

2. The thin film bulk acoustic resonator according to claim 1, characterized in that Along the thickness direction of the thin film bulk acoustic resonator, a projection of the second part on a plane where the substrate is located surrounds a projection of the first part on the plane where the substrate is located and the projection of the second part on the plane where the substrate is located is connected to the projection of the first part on the plane where the substrate is located.

3. The thin film bulk acoustic wave resonator according to claim 1, characterized in that, Along the thickness direction of the thin film bulk acoustic resonator, a projection of the first part on a plane where the substrate is located surrounds a projection of the second part on the plane where the substrate is located and the projection of the first part on the plane where the substrate is located is connected to the projection of the second part on the plane where the substrate is located.

4. The thin film bulk acoustic wave resonator according to claim 1, wherein The second part includes a first sub-part and a second sub-part; Along the thickness direction of the thin film bulk acoustic resonator, a projection of the first part on a plane where the substrate is located surrounds a projection of the first sub-part on the plane where the substrate is located, and a projection of the second sub-part on the plane where the substrate is located surrounds a projection of the first part on the plane where the substrate is located; The projection of the first part on the plane where the substrate is located is connected to the projection of the first sub-part on the plane where the substrate is located, and the projection of the first part on the plane where the substrate is located is connected to the projection of the second sub-part on the plane where the substrate is located.

5. The thin film bulk acoustic wave resonator according to claim 1, wherein The first part includes a third sub-part and a fourth sub-part; a thickness of the third sub-part is different from a thickness of the fourth sub-part; Along the thickness direction of the thin film bulk acoustic resonator, a projection of the fourth sub-part on a plane where the substrate is located surrounds a projection of the third sub-part on the plane where the substrate is located, and a projection of the second part on the plane where the substrate is located surrounds a projection of the fourth sub-part on the plane where the substrate is located; The projection of the fourth sub-part on the plane where the substrate is located is connected to the projection of the third sub-part on the plane where the substrate is located, and the projection of the fourth sub-part on the plane where the substrate is located is connected to the projection of the second part on the plane where the substrate is located.

6. The thin film bulk acoustic wave resonator according to claim 1, wherein The thickness of the first part is the same as the thickness of the second part.

7. The thin film bulk acoustic resonator according to claim 1, characterized in that, The first part and the second part are not connected to each other.

8. The thin film bulk acoustic wave resonator according to claim 1, wherein It further includes an airfoil and an air bridge formed by the second electrode layer and the piezoelectric layer; Along the thickness direction of the thin film bulk acoustic wave resonator, the projection of the airfoil on the plane where the substrate is located does not overlap with the projection of the temperature compensation layer on the plane where the substrate is located; the projection of the air bridge on the plane where the substrate is located does not overlap with the projection of the temperature compensation layer on the plane where the substrate is located.

9. A method for preparing a thin film bulk acoustic resonator, characterized in that, For preparing the thin film bulk acoustic wave resonator according to any one of claims 1-8; the preparation method includes: Providing a substrate; Successively preparing a bottom electrode layer, a piezoelectric layer and a first electrode layer on one side of the substrate; Etching the first electrode layer to form a through groove; Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer; Preparing a second electrode layer on the side of the temperature compensation layer away from the first electrode layer; Wherein, the temperature compensation layer includes a first part and a second part; the first part is arranged in the through groove to form a concave structure on the surface of the transducer stack structure; the second part is arranged between the first electrode layer and the second electrode layer to form a convex structure on the surface of the transducer stack structure.

10. The preparation method according to claim 9, characterized in that, Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer includes: Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer; Etching the first part of the temperature compensation layer to form a third sub-part and a fourth sub-part with different thicknesses.

11. The preparation method according to claim 9, characterized in that, Etching the first electrode layer to form a through groove includes: Etching the first electrode layer to form a through groove and a groove; Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer includes: Preparing a temperature compensation layer on the side of the first electrode layer away from the piezoelectric layer so that the temperature compensation layer fills into the through groove and the groove; After preparing the second electrode layer on the side of the temperature compensation layer away from the first electrode layer, it further includes: Etching the transducer stack structure to form a release channel; Introducing a corrosion medium into the release channel to form a cavity in the substrate, and introducing the corrosion medium into the groove to corrode the temperature compensation layer in the groove to form an airfoil and an air bridge.

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