A MEMS device and a method for manufacturing the same

Abstract

The present invention relates to a MEMS device and a manufacturing method thereof, comprising: a surface acoustic wave filter including an interdigital transducer; a first structural layer located above the surface acoustic wave filter; a bulk acoustic wave filter including a carrier substrate, an acoustic reflection structure located on the surface of the carrier substrate, and a piezoelectric stacked structure on the acoustic reflection structure, the piezoelectric stacked structure including a first electrode, a piezoelectric layer, and a second electrode stacked in sequence; the first structural layer has a first cavity, and the effective resonance region of the piezoelectric stacked structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity. The present invention realizes vertical integration by providing the first structural layer with the first cavity between the surface acoustic wave filter and the bulk acoustic wave filter, so that the effective resonance region of the piezoelectric stacked structure and the interdigital transducer of the surface acoustic wave filter jointly cover the first cavity, thereby reducing the packaging volume of the entire system, achieving miniaturization, and greatly improving the integration level.

Description

Technical Field

[0001] The present invention relates to the field of MEMS device manufacturing, and in particular to a MEMS device and a manufacturing method thereof. Background Art

[0002] Micro-Electro-Mechanical System (MEMS) and integrated circuit (IC) are currently the two most important development areas in the semiconductor industry. Driven by the rapid development of global science and technology, the integration of MEMS and IC has become an inevitable trend. There are three integration methods: monolithic integration, semi-hybrid (bonding) integration and hybrid integration; monolithic integration refers to the manufacture of MEMS structure and CMOS on a chip; hybrid integration is to manufacture MEMS and IC on different dies respectively, and then package them in a tube shell, and connect the MEMS bare die with bumps to the IC chip in the form of flip-chip or wire bonding to form SIP; semi-hybrid is to use three-dimensional integration technology to achieve three-dimensional integration of MEMS chip and CMOS; monolithic integration is an important development direction of MEMS and IC integration technology, especially for RF thin film bulk acoustic wave filters, there are many advantages, first, the processing circuit is close to the microstructure, and the detection and reception of signals can achieve higher accuracy; second, the integrated system is reduced in size and power consumption is low; third, the number of devices is reduced, the number of package pins is reduced, and the reliability is high.

[0003] In the existing radio frequency (RF) bulk acoustic wave filter manufacturing technology, most of them use system in a package (SIP) to seal the filter, drive circuit and processing circuit together. As the requirements for RF system performance become higher and higher, it is necessary to make filters of multiple frequency bands on a wafer. Due to the process and device characteristics of bulk acoustic wave filters, it is difficult to make filters of multiple frequency bands on a wafer. Even if it can be achieved, the process complexity is very high. However, bulk acoustic wave filters have significant advantages, such as low insertion loss and high isolation. Bulk acoustic wave filters must be used in some applications.

[0004] Therefore, the MEMS devices currently manufactured have problems such as single frequency band, low integration and complicated manufacturing process, and cannot meet the needs of high-performance RF systems. Summary of the invention

[0005] The object of the present invention is to provide a MEMS device and a method for manufacturing the same, which can solve the technical problems of the manufactured MEMS device having a single frequency band, low integration and complicated manufacturing process.

[0006] To achieve the above object, the present invention proposes a MEMS device, comprising:

[0007] A surface acoustic wave filter, the surface acoustic wave filter comprising an interdigital transducer;

[0008] a first structural layer, wherein the first structural layer is located above the surface acoustic wave filter;

[0009] A bulk acoustic wave filter, the bulk acoustic wave filter is located above the first structural layer; the bulk acoustic wave filter comprises a carrier substrate, an acoustic reflection structure located on the surface of the carrier substrate, and a piezoelectric stacked structure on the acoustic reflection structure, the piezoelectric stacked structure comprises a first electrode, a piezoelectric layer, and a second electrode stacked in sequence;

[0010] The first structural layer has a first cavity, and the effective resonance region of the piezoelectric stacked structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity.

[0011] The present invention also provides a method for manufacturing a MEMS device, comprising:

[0012] A surface acoustic wave filter is provided, wherein the surface acoustic wave filter comprises an interdigital transducer;

[0013] A bulk acoustic wave filter is provided, the bulk acoustic wave filter comprising: a carrier substrate, a support layer formed on a surface of the carrier substrate, and a piezoelectric stacked structure that forms a second cavity with the carrier substrate and the support layer;

[0014] The bulk acoustic wave filter is bonded to the surface acoustic wave filter through a first structural layer and forms a first cavity with the surface acoustic wave filter;

[0015] The effective resonance region of the piezoelectric stack structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity.

[0016] The beneficial effects of the structure of the present invention are:

[0017] By providing a first structural layer with a first cavity between the surface acoustic wave filter and the bulk acoustic wave filter, the effective resonance area of ​​the piezoelectric stacked structure of the bulk acoustic wave filter and the interdigital transducer of the surface acoustic wave filter jointly cover the first cavity, thereby realizing vertical integration, reducing the packaging volume of the entire system, achieving miniaturization, and greatly improving the integration level; not only retaining the advantages of high frequency and low insertion loss of the bulk acoustic wave filter, but also reducing the process cost to meet the needs of multiple frequency bands; the effective resonance area of ​​the piezoelectric stacked structure is located in the first cavity, which effectively improves the quality factor of the bulk acoustic wave filter.

[0018] Furthermore, electrical connection structures are formed respectively by the BAW filter and the SAW filter to achieve electrical connection with an external circuit, thereby avoiding mutual interference between the SAW filter and the BAW filter signals and improving the performance of the MEMS device.

[0019] Furthermore, an effective resonance region of the BAW filter is defined by the first groove and the second groove, and the first groove and the second groove respectively penetrate the first electrode and the second electrode, and the piezoelectric layer maintains a complete film layer without being etched, thereby ensuring the structural strength of the BAW filter and improving the yield of the BAW filter.

[0020] Beneficial effects of the production method of the present invention:

[0021] The BAW filter is bonded to the SAW filter through a bonding process and forms a first cavity with the SAW filter; the effective resonance area of ​​the piezoelectric stack structure and the interdigital transducer of the SAW filter cover the first cavity, so that the functional areas of the SAW filter and the BAW filter share a cavity, thereby realizing vertical integration, reducing the packaging volume of the entire system, achieving miniaturization, and greatly improving the integration level; not only retaining the advantages of high frequency and low insertion loss of the BAW filter, simplifying the manufacturing process, but also reducing the production cost; the effective resonance area of ​​the piezoelectric stack structure is located in the first cavity, so that the upper and lower surfaces of the effective resonance area are completely in the air, effectively improving the quality factor of the BAW filter.

[0022] Furthermore, at least one of the surface acoustic wave filter and the bulk acoustic wave filter is a wafer, and subsequent processes such as bonding and electrical connection are completed on the wafer size, realizing the demand for simultaneously manufacturing filters of different frequency bands on a single wafer, reducing the process difficulty and greatly improving the output.

[0023] Furthermore, the first structural layer is a photolithographically-capable organic curing film, which can relieve the bonding stress between the surface acoustic wave filter and the bulk acoustic wave filter, and has high bonding reliability with the surface acoustic wave filter and the bulk acoustic wave filter. The first cavity can be obtained by photolithography with low damage to the filter surface.

[0024] Furthermore, forming a passivation layer on the surface acoustic wave filter can improve the dustproof, waterproof and corrosion-resistant effects of the surface acoustic wave filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the structure of a MEMS device provided by an embodiment of the present invention;

[0027] Figures 2 to 6 A schematic diagram of structures corresponding to different steps in a method for manufacturing a MEMS device provided in one embodiment of the present invention;

[0028] Figures 7 to 10 A schematic diagram of structures corresponding to different steps in a method for manufacturing a MEMS device provided in one embodiment of the present invention;

[0029] Figure 11 to Figure 12 It is a structural schematic diagram corresponding to different steps in a method for manufacturing a MEMS device provided in an embodiment of the present invention.

[0030] Figure numerals: 10, supporting substrate; 11, interdigital transducer; 12, passivation layer; 121, oxide layer; 122, etch stop layer; 13, first structural layer; 14, first electrical connection structure; 141, first conductive interconnection layer; 15, second electrical connection structure; 151, second conductive interconnection layer; 16, third electrical connection structure; 17, fourth electrical connection structure; 18, interconnection line; 19, conductive protrusion; 20, dielectric layer; 100, supporting substrate; 101, supporting layer; 102, first electrode; 103, piezoelectric layer; 104', second electrode layer; 104, second electrode; 105, first groove; 106, second groove; 110a, second cavity; 120a, first cavity; 120a', first isolation groove. DETAILED DESCRIPTION

[0031] The substrate material of the surface acoustic wave filter is lithium niobate or lithium tantalate. The material properties and thermal expansion coefficient are different from those of ordinary substrates. It is easy to break and difficult to combine with the commonly used silicon wafer process. Therefore, it is not easy to integrate the surface acoustic wave filter with the bulk acoustic wave filter wafer-level process in the existing technology; in addition, due to the process and device characteristics of the bulk acoustic wave filter, it is relatively difficult to realize the production of filters with multiple frequency bands on a wafer. Even if it can be realized, its process complexity is very high. However, the advantages of the bulk acoustic wave filter are significant, such as low insertion loss and high isolation. The bulk acoustic wave filter must be used in some applications; the process and device characteristics of the surface acoustic wave filter determine that it is easy to realize the production of multiple frequency bands on a wafer, so the use of the surface acoustic wave filter is more cost-effective. Therefore, how to bond the surface acoustic wave filter with the bulk acoustic wave filter to solve the current problems of the single frequency band, low integration and complicated manufacturing process of MEMS devices is an urgent problem to be solved.

[0032] The following is a further detailed description of the MEMS device and the method for manufacturing the same in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description and drawings. However, it should be noted that the concept of the technical solution of the present invention can be implemented in a variety of different forms and is not limited to the specific embodiments described herein. The drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0033] The terms "first", "second", etc. in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms used in this way are interchangeable, for example, so that the embodiments of the invention described herein can be operated in an order other than that described or shown herein. Similarly, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method. If the components in a certain figure are the same as the components in other figures, although these components can be easily identified in all figures, in order to make the description of the figures clearer, this specification will not mark all the same component numbers in each figure.

[0034] Example 1

[0035] This embodiment 1 provides a MEMS device, Figure 1 FIG. 1 shows a schematic diagram of the structure of a MEMS device of the present embodiment 1, please refer to FIG. Figure 1 , the MEMS device comprises:

[0036] A surface acoustic wave filter, wherein the surface acoustic wave filter comprises an interdigital transducer 11;

[0037] A first structural layer 13, wherein the first structural layer 13 is located above the surface acoustic wave filter;

[0038] A bulk acoustic wave filter, the bulk acoustic wave filter is located above the first structural layer 13; the bulk acoustic wave filter includes a carrier substrate 100, an acoustic reflection structure (not shown in the figure) located on the surface of the carrier substrate 100, and a piezoelectric stacked structure on the acoustic reflection structure, the piezoelectric stacked structure includes a first electrode 102, a piezoelectric layer 103 and a second electrode 104 stacked in sequence;

[0039] The first structural layer 13 has a first cavity 120a, and the effective resonance region of the piezoelectric stacked structure and the interdigital transducer 11 of the surface acoustic wave filter cover the first cavity 120a.

[0040] The bulk acoustic wave filter can also be a thin film bulk acoustic wave resonator or a solid-state assembled resonator. When the sound reflection structure includes a cavity, it can be a bulk acoustic wave filter or a thin film bulk acoustic wave resonator. When the sound reflection structure includes a Bragg reflection layer, it can be a solid-state assembled resonator. This embodiment takes the bulk acoustic wave filter as an example to explain the present invention in detail.

[0041] The first cavity 120a can be formed by etching the first structure layer 13 through an etching process. However, the technology of the present invention is not limited to this. It should be noted that there is a bonding interface between the first structure layer 13 and the bulk acoustic wave filter, and the first structure layer 13 is bonded to the bulk acoustic wave filter through the bonding interface. The first structure layer 13 is bonded to the first structure layer 13 on the surface acoustic wave filter through a bonding process, and the first cavity 120a is formed with the surface acoustic wave filter. The vertical integration of the bulk acoustic wave filter and the surface acoustic wave filter is realized in the device manufacturing stage, the system-level packaging process at the back end is omitted, the manufacturing process is simplified, the packaging volume of the entire system is reduced, and the integration is greatly improved; the bonding method includes: metal bonding, covalent bonding, adhesive bonding or melt bonding. The first structure layer and the filter are bonded through a bonding layer, and the material of the bonding layer includes a photolithographic organic curable film, silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate or metal. In other embodiments, the first structural layer 13 may also be located on the bulk acoustic wave filter, with a bonding interface between the first structural layer 13 and the surface acoustic wave filter. The first structural layer 13 is bonded to the surface acoustic wave filter through the bonding interface, thereby realizing the bonding connection between the bulk acoustic wave filter and the surface acoustic wave filter.

[0042] In this embodiment, the bottom surface of the first cavity 120a is in a rectangular shape. However, in other embodiments, the first cavity 120a may also be in a circular shape, an elliptical shape, or a polygon other than a rectangle, such as a pentagon or a hexagon.

[0043] It should be noted that, by providing a first structural layer 13 with a first cavity 120a between the surface acoustic wave filter and the bulk acoustic wave filter, the effective resonance area of ​​the piezoelectric stack structure and the interdigital transducer 11 of the surface acoustic wave filter jointly cover the first cavity 120a, thereby realizing vertical integration, reducing the packaging volume of the entire system, achieving miniaturization, and greatly improving the integration level; not only retaining the advantages of high frequency and low insertion loss of the bulk acoustic wave filter, but also reducing the process cost to meet the needs of multi-band; the effective resonance area of ​​the piezoelectric stack structure is located in the first cavity 120a, which effectively improves the quality factor of the bulk acoustic wave filter.

[0044] The effective resonance region of the piezoelectric stacked structure and the IDT 11 of the surface acoustic wave filter jointly cover the first cavity 120a, such as the effective resonance region and the IDT 11 face the first cavity 120a, respectively cover the first cavity 120a, or at least one of them protrudes into the first cavity 120a.

[0045] In this embodiment, the first cavity 120a penetrates the first structural layer 13; the first structural layer 13 includes a photolithographic organic curable film or an oxide layer. In this embodiment, the first structural layer 13 is a photolithographic organic curable film, which has single-sided or double-sided adhesiveness, a film material or a liquid material, can be photolithographic, can be cured, has a relatively small elastic modulus, can relieve the bonding stress between the surface acoustic wave filter and the bulk acoustic wave filter, and has high bonding reliability with the surface acoustic wave filter and the bulk acoustic wave filter. The first cavity 120a is obtained by photolithography of the first structural layer 13, which causes less damage to the filter surface, further improving the quality factor of the device. The thickness range of the first structural layer 13 includes 5 to 50 μm. The surface acoustic wave filter is subsequently bonded to the bulk acoustic wave filter, which needs to reach a certain thickness, and the first isolation groove subsequently formed on the first structural layer 13 also needs to have a certain depth. Therefore, in this embodiment, by limiting the thickness range of the first structural layer 13 to 5 to 50 μm, the bonding conditions of the surface acoustic wave filter and the subsequent bulk acoustic wave filter can be met and costs can be saved. In other embodiments, the thickness range of the first structure layer 13 may also be higher or lower than this range.

[0046] In this embodiment, a passivation layer 12 is provided between the first structural layer 13 and the surface acoustic wave filter. By providing the passivation layer 12 on the surface acoustic wave filter, the surface acoustic wave filter can be protected and the structural strength and device performance of the surface acoustic wave filter can be improved. The passivation layer 12 includes an oxide layer 121 and an etching stop layer 122. The oxide layer 121 is located on the upper surface of the surface acoustic wave filter. The etching stop layer 122 is located on the oxide layer 121. The material of the oxide layer 121 is at least one of any insulating materials such as silicon oxide, silicon oxynitride, and silicon nitride. By providing the oxide layer 121 on the surface of the surface acoustic wave filter, the dustproof and waterproof effects of the surface acoustic wave filter are improved. An etching stop layer 122 is provided on the oxide layer 121. The material of the etching stop layer 122 includes but is not limited to silicon nitride and silicon oxynitride. In this embodiment, it is silicon nitride. Silicon nitride has a high density and strength, and can improve the waterproof and corrosion-resistant effects of the surface acoustic wave filter.

[0047] In addition, the etch stop layer 122 can be used to increase the structural stability of the filter finally manufactured on the one hand, and on the other hand, the etch stop layer 122 has a lower etching rate than the photolithographic organic curing film, and can prevent over-etching in the process of etching the organic curing film to form the first cavity 110a, protecting the surface of the structure located thereunder from damage, thereby improving device performance and reliability.

[0048] In other embodiments, the passivation layer 12 may also include only one of the oxide layer 121 and the etch stop layer 122 , or the passivation layer 12 may also be other structures, which are not limited here.

[0049] In this embodiment, the surface acoustic wave filter further includes a carrier substrate 10 and a dielectric layer 20 located on the carrier substrate 10 .

[0050] It should be noted that the surface acoustic wave filter is composed of a layer of metal film evaporated on a material substrate with piezoelectric effect, and then a pair of interdigital electrodes are formed at both ends through photolithography; the surface acoustic wave filter has the advantages of high working efficiency, wide bandwidth, good frequency selection characteristics, small size and light weight, and can adopt the same production process as integrated circuits, with simple manufacturing and low cost.

[0051] The carrier substrate 10 has a first surface and a second surface opposite to each other, the dielectric layer 20 is located on the first surface of the carrier substrate 10, and the interdigital transducer 11 is located in the dielectric layer 20 on the first surface of the carrier substrate 10. The interdigital transducer 11 includes a transmitting transducer and a receiving transducer. When a signal voltage is applied to the transmitting transducer, an electric field is formed between the input interdigital electrodes to cause the piezoelectric material to vibrate mechanically and propagate to both sides in the form of ultrasonic waves. The receiving transducer converts the mechanical vibration into an electrical signal, which is output by the output interdigital electrodes.

[0052] In this embodiment, the BAW filter is located above the first structural layer 13; the BAW filter includes a carrier substrate 100, a support layer 101 located on the surface of the carrier substrate 100, and a piezoelectric stacked structure that forms a second cavity 110a with the carrier substrate 100 and the support layer 101.

[0053] Specifically, the projections of the first cavity 120a and the second cavity 110a on the piezoelectric stack structure at least partially overlap, so that the upper and lower surfaces of the effective resonance region of the piezoelectric stack structure are both in the air, which can further improve the quality factor of the BAW filter.

[0054] The carrier substrate 100 can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (SiC), carbon germanium silicon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, etc., and can also be a ceramic substrate such as aluminum oxide, a quartz or glass substrate, etc.

[0055] The support layer 101 is bonded to the carrier substrate 100, and forms a second cavity 110a with the piezoelectric stack structure, and the second cavity 110a exposes the carrier substrate 100. In the present embodiment, the second cavity 110a is an annular closed cavity, and the second cavity 110a can be formed by etching the support layer through an etching process. However, the technology of the present invention is not limited to this. It should be noted that the support layer 101 is combined with the carrier substrate 100 by bonding, and the bonding methods include: metal bonding, covalent bonding, adhesive bonding or melt bonding. In the present embodiment, the support layer 101 and the carrier substrate 100 are bonded through a bonding layer, and the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.

[0056] In this embodiment, the shape of the bottom surface of the second cavity 110a is a rectangle, but in other embodiments of the present invention, the shape of the second cavity 110a on the bottom surface of the first electrode 102 may also be a circle, an ellipse, or a polygon other than a rectangle, such as a pentagon, a hexagon, etc. The material of the support layer 101 may be any suitable dielectric material, including but not limited to one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc. The material of the support layer 101 and the bonding layer may be the same.

[0057] A piezoelectric stack structure is disposed above the second cavity 110a, and the piezoelectric stack structure sequentially includes a first electrode 102, a piezoelectric layer 103, and a second electrode 104. The first electrode 102 is located on the support layer 101, the piezoelectric layer 103 is located on the first electrode 102, and the second electrode 104 is located on the piezoelectric layer 103.

[0058] In this embodiment, the piezoelectric layer 103 covers the second cavity 110a. Covering the second cavity 110a should be understood as the piezoelectric layer 103 being a complete film layer that has not been etched. It does not mean that the piezoelectric layer 103 completely covers the second cavity 110a to form a sealed cavity. Of course, the piezoelectric layer 103 can completely cover the second cavity 110a to form a sealed cavity. The piezoelectric layer 103 is not etched to ensure that the piezoelectric stack structure has a certain thickness, so that the bulk acoustic wave filter has a certain structural strength. Improve the yield rate of bulk acoustic wave filters.

[0059] In one embodiment, an etch stop layer is further provided between the support layer 101 and the first electrode 102, and its material includes but is not limited to silicon nitride (Si3N4) and silicon oxynitride (SiON). The etch stop layer can be used to increase the structural stability of the final bulk acoustic wave resonator on the one hand, and on the other hand, the etch stop layer has a lower etching rate than the support layer 101, and can prevent over-etching in the process of etching the support layer 101 to form the second cavity 110a, protecting the surface of the first electrode 102 thereunder from damage, thereby improving device performance and reliability.

[0060] In this embodiment, the surface of the piezoelectric stack structure further includes a first groove 105 and a second groove 106. The first groove 105 is located on the bottom of the lower surface of the piezoelectric stack structure and the side where the second cavity 110a is located, and penetrates the first electrode 102. The second groove 106 is located on the upper surface of the piezoelectric stack structure and penetrates the second electrode 104. The two ends of the first groove 105 are arranged opposite to the two ends of the second groove 106, so that the first groove 105 and the second groove 106 are connected or have a gap at two intersections of the projection of the carrier substrate 100. In this embodiment, the projection of the first groove 105 and the second groove 106 on the carrier substrate 100 is a closed figure. The first electrode 102, the piezoelectric layer 103 and the second electrode 104 above the second cavity 120a are provided with an overlapping area in a direction perpendicular to the supporting substrate 100. The overlapping area between the first groove 105 and the second groove 106 is an effective resonance area. The effective resonance area of ​​the bulk acoustic wave filter is defined by the first groove 105 and the second groove 106. The first groove 105 and the second groove 106 penetrate the first electrode 102 and the second electrode 104 respectively. The piezoelectric layer 103 maintains a complete film layer without being etched, thereby ensuring the structural strength of the bulk acoustic wave filter and improving the yield of the bulk acoustic wave filter.

[0061] In this embodiment, the surface acoustic wave filter is electrically connected to the external circuit through the first electrical connection structure 14 and the fourth electrical connection structure 17, and the bulk acoustic wave filter is electrically connected to the external circuit through the second electrical connection structure 15 and the third electrical connection structure 16. By forming electrical connection structures respectively between the bulk acoustic wave filter and the surface acoustic wave filter, electrical connection with the external circuit is achieved, which avoids mutual interference between the signals of the surface acoustic wave filter and the bulk acoustic wave filter, thereby improving the performance of the MEMS device.

[0062] The first electrical connection structure 14 includes a first interconnection hole (not shown in the figure) and a first conductive interconnection layer 141 located in the first interconnection hole, wherein the first interconnection hole penetrates from one side of the carrier substrate 100 and extends to the interdigital transducer 11 of the surface acoustic wave filter;

[0063] The second electrical connection structure 15 includes a second interconnection hole (not shown in the figure) and a second conductive interconnection layer 151 located in the second interconnection hole. The second interconnection hole passes through one side of the carrier substrate 100 and extends to the first electrode 102 outside the effective resonance region of the piezoelectric stack structure.

[0064] The carrier substrate 100 is provided with an interconnection line 18 , the first conductive interconnection layer 141 includes a first plug, the second conductive interconnection layer 151 includes a second plug, and the first plug and the second plug are electrically connected to the interconnection line 18 .

[0065] It should be noted that the input and output ends of the interdigital transducer 11 are provided with interdigital electrodes. The first electrical connection structure is used to introduce an electrical signal into the input end of the interdigital transducer. When an electrical signal is input into the input end of the interdigital transducer, under the action of the alternating electric field of the input electrical signal, due to the piezoelectric effect of the crystal, mechanical vibration is excited on the substrate surface of the interdigital transducer to form a surface acoustic wave. The fourth electrical connection structure is used to connect the output end of the interdigital transducer. The surface acoustic wave formed at the input end propagates along the substrate surface to the interdigital electrode at the output end. Due to the pressure effect, the mechanical vibration generates an electric field change, and the electrical signal is output at the output end. The second electrical connection structure is used to introduce an electrical signal into the second electrode of the effective resonance zone. The third electrical connection structure is used to introduce an electrical signal into the first electrode of the effective resonance zone. After the first electrode 103 and the second electrode 105 are energized, a pressure difference is generated between the upper and lower surfaces of the piezoelectric layer 104 to form a standing wave oscillation. The specific structures of the first electrical connection structure 14 and the second electrical connection structure 15 are as follows:

[0066] The first electrical connection structure 14 includes:

[0067] A first interconnection hole, wherein the first interconnection hole penetrates from one side of the carrier substrate 100 and extends to the interdigital transducer 11 of the surface acoustic wave filter;

[0068] A first conductive interconnection layer 141 covers the inner surface of the first interconnection hole and is electrically connected to the interconnection line 18 located on the surface of the carrier substrate 100;

[0069] The second electrical connection structure 15 comprises:

[0070] a second interconnection hole, wherein the second interconnection hole penetrates through one side of the carrier substrate 100 and extends to the first electrode 102 outside the effective resonance region of the piezoelectric stack structure and exposes the first electrode 102;

[0071] The second conductive interconnection layer 151 covers the inner surface of the second interconnection hole and is electrically connected to the interconnection line 18 located on the surface of the carrier substrate 100 .

[0072] It should be noted that the second electrical connection structure 15 is not directly electrically connected to the second electrode 104, but is connected to the first electrode 102 outside the effective resonance region, and is electrically connected to the second electrode 104 in the effective resonance region through a conductive interconnection structure (not shown in the figure). The third electrical connection structure 16 is electrically connected to the first electrode 102 inside the effective resonance region to supply power to the first electrode 102 inside the effective resonance region. It can be seen that the first electrical connection structure 14 and the fourth electrical connection structure 17 are structurally consistent, but the locations are different. The second electrical connection structure 15 and the third electrical connection structure 16 are also structurally consistent, but the locations are different. The structures of the third electrical connection structure 16 and the fourth electrical connection structure 17 are not repeated here.

[0073] In this embodiment, the MEMS device further includes:

[0074] An insulating layer, covering the interconnection line 18 and the surface of the carrier substrate 100;

[0075] The conductive protrusion 19 is disposed on the surface of the carrier substrate 100 and is electrically connected to the interconnection line 18 .

[0076] Example 2

[0077] Embodiment 2 of the present invention provides a method for manufacturing a MEMS device, comprising the following steps:

[0078] S01: providing a surface acoustic wave filter, wherein the surface acoustic wave filter comprises an interdigital transducer;

[0079] S02: providing a bulk acoustic wave filter, the bulk acoustic wave filter comprising: a carrier substrate, a support layer formed on a surface of the carrier substrate, and a piezoelectric stacked structure that forms a second cavity with the carrier substrate and the support layer;

[0080] S03: The bulk acoustic wave filter is bonded to the surface acoustic wave filter through a first structural layer and forms a first cavity with the surface acoustic wave filter;

[0081] S04: The effective resonance region of the piezoelectric stacked structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity.

[0082] Steps S0N do not represent a sequential order.

[0083] refer to Figures 2 to 12 The schematic diagram of the structure corresponding to the corresponding steps of the method for manufacturing the MEMS device of this embodiment, refer to Figures 2 to 12 , a method for manufacturing the MEMS device provided in this embodiment is described in detail.

[0084] refer to Figure 2 As shown, a surface acoustic wave filter is provided.

[0085] The formation process of the surface acoustic wave filter includes:

[0086] Providing a carrier substrate 10;

[0087] forming an interdigital transducer 11 on the carrier substrate 10;

[0088] Forming a dielectric layer 20 on the first surface of the carrier substrate 10, wherein the dielectric layer 20 covers the first surface of the carrier substrate 10 and the interdigital transducer 11;

[0089] The carrier substrate 10 includes a first surface and a second surface opposite to each other. The IDT 11 is formed on the first surface of the carrier substrate 10 .

[0090] The working principle of the IDT 11 is similar to that of the aforementioned embodiment 1 and will not be described in detail here.

[0091] refer to Figure 3 to Figure 4 As shown, a passivation layer 12 is formed on the surface acoustic wave filter.

[0092] The specific process of forming the passivation layer 12 includes:

[0093] refer to Figure 3 , an oxide layer 121 is formed on the dielectric layer 20 .

[0094] The material and function of the oxide layer 121 refer to the aforementioned embodiment 1 and will not be described in detail here.

[0095] refer to Figure 4 , an etch stop layer 122 is formed on the oxide layer 121 , and the etch stop layer 122 and the oxide layer 121 constitute the passivation layer 12 .

[0096] The material and function of the etching stop layer 122 refer to the aforementioned embodiment 1 and will not be described in detail here.

[0097] refer to Figure 5 In one embodiment, a first structure layer 13 is formed on the passivation layer 12 .

[0098] The first structural layer 13 is a photolithographically-capable organic curable film, and the function of the organic curable film is the same as that in the first embodiment.

[0099] In another embodiment, the first structure layer 13 is not formed on the passivation layer 12, but can be formed on the piezoelectric stacked structure of the bulk acoustic wave filter. For a specific formation process, please refer to the following Figures 7 to 10 , no further description will be given here.

[0100] refer to Figure 6, the first structural layer 13 is etched to form a first isolation groove 120a', so that the interdigital converter 11 is opposite to the first isolation groove 120a'.

[0101] refer to Figures 7 to 9 , providing a bulk acoustic wave filter, the bulk acoustic wave filter comprising: a carrier substrate, a support layer formed on the surface of the carrier substrate, and a piezoelectric stacked structure that forms a second cavity with the carrier substrate and the support layer. For details on the specific formation process of the bulk acoustic wave filter, please refer to Figure 7-Figure 9 .

[0102] refer to Figure 7 , providing a temporary substrate 200.

[0103] The temporary substrate 200 may be any suitable substrate known to those skilled in the art, and may be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), indium arsenide (Ins), indium phosphide (InP) or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI) and germanium on insulator (GeOI), or may also be double-sided polished silicon wafers (DSP), or may also be ceramic substrates such as alumina, quartz or glass substrates, etc. In this embodiment, the temporary substrate 200 is <100> P-type high-resistance single-crystal silicon wafer with different crystal orientations.

[0104] A second electrode layer 104 ′, a piezoelectric layer 103 and a first electrode 102 are sequentially formed on the temporary substrate 200 .

[0105] The materials of the second electrode layer 104' and the first electrode 102 can be any suitable conductive material or semiconductor material known to those skilled in the art, wherein the conductive material can be a metal material with conductive properties, for example, made of one of metals such as molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), or a stack of the above metals, and the semiconductor material can be, for example, Si, Ge, SiGe, SiC, SiGeC, etc. The second electrode layer 104' and the first electrode 102 can be formed by physical vapor deposition such as magnetron sputtering and evaporation or chemical vapor deposition. The material of the piezoelectric layer 103 can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3) and a combination thereof. When the piezoelectric layer 103 includes aluminum nitride (AlN), the piezoelectric layer 103 may also include a rare earth metal, such as scandium (Sc), erbium (Er), yttrium (Y) and lanthanum (La). In addition, when the piezoelectric layer includes aluminum nitride (AlN), the piezoelectric layer 103 may also include a transition metal, such as zirconium (Zr), titanium (Ti), manganese (Mn) and hafnium (Hf). The piezoelectric layer 103 can be deposited and formed by any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition. Optionally, in this embodiment, the second electrode layer 104 ′ and the first electrode 102 are made of metal molybdenum (Mo), and the piezoelectric layer 103 is made of aluminum nitride (AlN).

[0106] In the present embodiment, after the first electrode 102 is formed, the first groove 105 penetrating the first electrode 102 is formed by etching the first electrode 102. The first groove 105 is located in the first cavity 120a formed subsequently, and the sidewall of the first groove 105 may be inclined or vertical. In the present embodiment, the sidewall of the first groove 105 forms a right angle with the plane where the piezoelectric layer 103 is located (the longitudinal cross section (cross section along the thickness direction of the film layer) of the first groove 105 is rectangular). In other embodiments, the sidewall of the first groove 105 forms an obtuse angle with the plane where the piezoelectric layer 103 is located. The projection of the first groove 105 on the plane where the piezoelectric layer 103 is located is a semi-circular or semi-circular polygon.

[0107] refer to Figure 8 A carrier substrate 100 including a second cavity 110a is formed on the piezoelectric layer, the carrier substrate 100 covers a portion of the first electrode, and an effective resonance region of the first electrode is located within the boundary of the region enclosed by the second cavity 110a.

[0108] A support layer 101 is also formed on the piezoelectric layer, and the support layer 101 is bonded to the carrier substrate 100, and forms a second cavity 110a with the piezoelectric layer, and the second cavity 110a exposes the carrier substrate 100. In this embodiment, the second cavity 110a is an annular closed cavity, and the second cavity 110a can be formed by etching the support layer through an etching process. However, the technology of the present invention is not limited to this. It should be noted that the support layer 101 is combined with the carrier substrate 100 by bonding, and the bonding method includes: metal bonding, covalent bonding, adhesive bonding or melt bonding. In this embodiment, the support layer 101 and the carrier substrate 100 are bonded through a bonding layer, and the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.

[0109] In this embodiment, the shape of the bottom surface of the second cavity 110a is a rectangle, but in other embodiments of the present invention, the shape of the second cavity 110a on the bottom surface of the first electrode 102 may also be a circle, an ellipse, or a polygon other than a rectangle, such as a pentagon, a hexagon, etc. The material of the support layer 101 may be any suitable dielectric material, including but not limited to one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc. The material of the support layer 101 and the bonding layer may be the same.

[0110] refer to Fig. 9 , remove the temporary substrate 200.

[0111] After removing the temporary substrate 200, the second electrode layer 104' is patterned to form the second electrode 104, and the first electrode, the piezoelectric layer and the second electrode constitute a piezoelectric stack structure; a second groove 106 penetrating the second electrode 104 is formed on the second electrode 104; the second groove 106 is formed on the opposite side of the first groove 105. In this embodiment, the first groove 105 and the second groove 106 are connected at two intersections of the projection of the carrier substrate 100 to form a closed irregular polygon. The structure and formation method of the second groove 106 refer to the structure and formation method of the first groove 105. In other embodiments, only the first groove 105 or the second groove 106 can also be formed separately. The structure and function of the first groove 105 and the second groove 106 refer to Example 1 and are not repeated here.

[0112] The effective resonance region includes a region where the first electrode 102, the piezoelectric layer 103 and the second electrode 104 overlap each other in a direction perpendicular to the surface of the piezoelectric stacked structure.

[0113] refer to Fig.10In one embodiment, after forming the BAW filter, a first structure layer 13 is formed on the second electrode 104 , and the first structure layer 13 is etched to form a first isolation groove 120 a ′. The first isolation groove 120 a ′ at least exposes the effective resonance region of the second electrode 104 .

[0114] Before forming the first structure layer 13, it also includes forming an etch stop layer (not shown in the figure) on the second electrode 104, and forming the first structure layer 13 on the etch stop layer. The first structure layer 13 is an oxide layer. The materials and uses of the oxide layer and the etch stop layer refer to the previous embodiment and are not repeated here.

[0115] In another embodiment, the first structural layer 13 may also be formed on the surface acoustic wave filter. For details, please refer to the aforementioned Figures 2 to 6 .

[0116] refer to Fig.11 In one embodiment, based on Figure 6 , the BAW filter is bonded to the SAW filter, so that the first isolation groove 120a' is sandwiched between the SAW filter and the BAW filter to form the first cavity 120a.

[0117] In another embodiment, based on Figure 4 After forming the first structural layer 13 on the BAW filter, it is bonded to the SAW filter. The first structural layer 13 is bonded to the passivation layer 12 of the SAW filter, so that the first isolation groove 120a' is sandwiched between the SAW filter and the BAW filter to form the first cavity 120a.

[0118] The effective resonance region of the piezoelectric stacked structure and the interdigital transducer 11 of the surface acoustic wave filter cover the first cavity 120a.

[0119] The BAW filter is bonded to the SAW filter through a bonding process and forms a first cavity 120a with the SAW filter; the effective resonance region of the piezoelectric stack structure and the interdigital transducer 11 of the SAW filter cover the first cavity 120a, so that the functional regions of the SAW filter and the BAW filter share a cavity, thus realizing vertical integration, reducing the packaging volume of the entire system, achieving miniaturization, and greatly improving the integration level; not only retaining the advantages of the BAW filter in high frequency and low insertion loss, simplifying the manufacturing process, but also reducing the production cost; the effective resonance region of the piezoelectric stack structure is located in the first cavity 120a, so that the upper and lower surfaces of the effective resonance region are completely in the air, effectively improving the quality factor of the BAW filter.

[0120] Furthermore, at least one of the surface acoustic wave filter and the bulk acoustic wave filter is a wafer, and subsequent processes such as bonding and electrical connection are completed on the wafer size, realizing the demand for simultaneously manufacturing filters of different frequency bands on a single wafer, reducing the process difficulty and greatly improving the output.

[0121] refer to Fig.12 After bonding the BAW filter and the SAW filter, it also includes: the SAW filter forms a first electrical connection structure 14 and a fourth electrical connection structure 17 electrically connected to an external circuit, and the BAW filter forms a second electrical connection structure 15 and a third electrical connection structure 16 electrically connected to an external circuit.

[0122] The method for forming the first electrical connection structure 14 includes:

[0123] A first interconnection hole (not shown in the figure) is formed by an etching process, wherein the first interconnection hole penetrates through one side of the carrier substrate 100 and extends to the interdigital transducer 11 of the surface acoustic wave filter;

[0124] forming a first conductive interconnection layer 141 in the first interconnection hole, wherein the first conductive interconnection layer 141 covers an inner surface of the first interconnection hole;

[0125] The method for forming the second electrical connection structure 15 includes:

[0126] A second interconnection hole (not shown in the figure) is formed by an etching process, wherein the second interconnection hole penetrates through one side of the carrier substrate 100 and extends to the first electrode 102 outside the effective resonance region of the piezoelectric stack structure;

[0127] A second conductive interconnection layer 151 is formed in the second interconnection hole, and the second conductive interconnection layer 151 covers the inner surface of the second interconnection hole.

[0128] After forming the first electrical connection structure 14 and the second electrical connection structure 15, an interconnection line 18 is formed on the surface of the carrier substrate 100; an insulating layer is formed on the interconnection line 18, and the insulating layer covers the interconnection line 18 and the surface of the carrier substrate 100; a conductive protrusion 19 is arranged on the surface of the carrier substrate 100 and electrically connected to the interconnection line 18, and the conductive protrusion 19 is electrically connected to an external circuit, and the first conductive interconnection layer 141 and the second conductive interconnection layer 151 are electrically connected to the interconnection line 18.

[0129] In this embodiment, the first conductive interconnection layer 141 includes a first plug, and the second conductive interconnection layer 151 includes a second plug.

[0130] Specifically, one end of the first plug is connected to the input end of the interdigital transducer 11, which is used to provide a signal voltage to the transmitting transducer, and the other end is connected to the interconnection line 18, which is used to connect to an external circuit; one end of the second plug is connected to the first electrode 102 outside the effective resonance region, which is used to introduce an electrical signal into the second electrode 104 of the effective resonance region; the third electrical connection structure 16 is used to introduce an electrical signal into the first electrode 102 of the effective resonance region. After the first electrode 102 and the second electrode 104 are energized, a pressure difference is generated on the upper and lower surfaces of the piezoelectric layer 103, forming a standing wave oscillation. The fourth electrical connection structure 17 is used to connect the output end of the interdigital transducer 11. The acoustic surface wave formed at the input end propagates along the substrate surface to the interdigital electrode at the output end. Due to the pressure effect, the electric field changes due to mechanical vibration, and the electrical signal is output at the output end. The formation method of the third electrical connection structure 16 is the same as that of the second electrical connection structure 15, and the formation method of the fourth electrical connection structure 17 is the same as that of the first electrical connection structure 14, which will not be repeated here.

[0131] It should be noted that the process of completing the bonding of the above surface acoustic wave filter and the bulk acoustic wave filter also includes placing multiple surface acoustic wave filters in a surface acoustic wave filter wafer, and / or placing multiple bulk acoustic wave filters in a bulk acoustic wave filter wafer. After the bonding step, it also includes separating and forming a single bonded body of the surface acoustic wave filter and the bulk acoustic wave filter.

[0132] 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 referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0133] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A MEMS device, characterized in that: include: A surface acoustic wave filter, the surface acoustic wave filter comprising an interdigital transducer; a first structural layer, wherein the first structural layer is located above the surface acoustic wave filter; A bulk acoustic wave filter, the bulk acoustic wave filter is located above the first structural layer; the bulk acoustic wave filter comprises a carrier substrate, an acoustic reflection structure located on the surface of the carrier substrate, and a piezoelectric stacked structure on the acoustic reflection structure, the piezoelectric stacked structure comprises a first electrode, a piezoelectric layer, and a second electrode stacked in sequence; The first structural layer has a first cavity, and the effective resonance region of the piezoelectric stacked structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity.

2. The MEMS device according to claim 1, characterized in that: The first cavity penetrates the first structural layer.

3. The MEMS device according to claim 1, characterized in that: The first structural layer includes a photolithographic organic curable film or an oxide layer.

4. The MEMS device according to claim 1, characterized in that: The thickness of the first structural layer ranges from 5 to 50 μm.

5. The MEMS device according to claim 1, characterized in that: A passivation layer is provided between the surface acoustic wave filter and the first structural layer. The passivation layer includes an oxide layer and an etch stop layer. The oxide layer is located on the upper surface of the surface acoustic wave filter, and the etch stop layer is located on the oxide layer.

6. The MEMS device according to claim 1, characterized in that: The acoustic reflection structure comprises a support layer located on the surface of the carrier substrate, and the carrier substrate, the support layer and the piezoelectric stacked structure form a second cavity of the bulk acoustic wave filter.

7. The MEMS device according to claim 1, characterized in that: The surface acoustic wave filter is electrically connected to an external circuit via a first electrical connection structure and a fourth electrical connection structure, and the bulk acoustic wave filter is electrically connected to an external circuit via a second electrical connection structure and a third electrical connection structure.

8. The MEMS device according to claim 7, characterized in that: The first electrical connection structure comprises a first interconnection hole and a first conductive interconnection layer located in the first interconnection hole, wherein the first interconnection hole penetrates from one side of the carrier substrate and extends to the interdigital transducer of the surface acoustic wave filter; The second electrical connection structure includes a second interconnection hole and a second conductive interconnection layer located in the second interconnection hole. The second interconnection hole penetrates from one side of the carrier substrate and extends to the first electrode outside the effective resonance region of the piezoelectric stack structure.

9. The MEMS device according to claim 8, characterized in that: An interconnection line is arranged on the carrier substrate, the first conductive interconnection layer includes a first plug, the second conductive interconnection layer includes a second plug, and the first plug and the second plug are electrically connected to the interconnection line.

10. The MEMS device according to claim 6, characterized in that: A first groove penetrating the first electrode is provided at the bottom of the second cavity, and a second groove penetrating the second electrode is provided at a position opposite to the first groove. The first groove and the second groove are connected or provided with a gap at two intersections of the projection of the supporting substrate.

11. The MEMS device according to claim 1, characterized in that: The sound reflection structure includes a Bragg reflection layer.

12. A method for manufacturing a MEMS device, characterized in that: include: A surface acoustic wave filter is provided, wherein the surface acoustic wave filter comprises an interdigital transducer; A bulk acoustic wave filter is provided, the bulk acoustic wave filter comprising: a carrier substrate, a support layer formed on a surface of the carrier substrate, and a piezoelectric stacked structure that forms a second cavity with the carrier substrate and the support layer; The bulk acoustic wave filter is bonded to the surface acoustic wave filter through a first structural layer and forms a first cavity with the surface acoustic wave filter; The effective resonance region of the piezoelectric stack structure and the interdigital transducer of the surface acoustic wave filter cover the first cavity; At least one of the surface acoustic wave filter and the bulk acoustic wave filter is a wafer, and the bonding process and subsequent electrical connection process are completed on the wafer size, so that filters of different frequency bands can be manufactured on a single wafer at the same time; The process of completing the bonding between the surface acoustic wave filter and the bulk acoustic wave filter further includes placing a plurality of surface acoustic wave filters in a surface acoustic wave filter wafer and / or placing a plurality of bulk acoustic wave filters in a bulk acoustic wave filter wafer.

13. The method for manufacturing a MEMS device according to claim 12, characterized in that: After the bonding step, the method further includes separating the bonded bodies into individual surface acoustic wave filters and bulk acoustic wave filters.

14. The method for manufacturing a MEMS device according to claim 12, characterized in that: The method of forming the first cavity comprises: Providing surface acoustic wave filters; forming a first structural layer on the surface acoustic wave filter; Etching the first structural layer to form a first isolation groove, so that the interdigital transducer is opposite to the first isolation groove; providing a bulk acoustic wave filter, wherein the bulk acoustic wave filter is bonded to the first structural layer, so that the first isolation groove is sandwiched between the surface acoustic wave filter and the bulk acoustic wave filter to form the first cavity; or, Providing surface acoustic wave filters; Providing a bulk acoustic wave filter, forming a first structural layer on the piezoelectric stacked structure; Etching the first structural layer to form a first isolation trench; The first structural layer is bonded to the surface acoustic wave filter, so that the first isolation groove is sandwiched between the surface acoustic wave filter and the bulk acoustic wave filter to form the first cavity.

15. The method for manufacturing a MEMS device according to claim 12, characterized in that: A passivation layer is formed between the surface acoustic wave filter and the first structure layer.

16. The method for manufacturing a MEMS device according to claim 15, characterized in that: The passivation layer includes an oxide layer and an etch stop layer, the oxide layer is formed on the surface acoustic wave filter, and the etch stop layer is formed on the oxide layer.

17. The method for manufacturing a MEMS device according to claim 12, characterized in that: A method of forming a bulk acoustic wave filter comprises: providing a temporary substrate; forming a piezoelectric stack structure on the temporary substrate, wherein the piezoelectric stack structure comprises a second electrode, a piezoelectric layer, and a first electrode formed in sequence from bottom to top on the temporary substrate surface; forming a support material layer to cover the piezoelectric stack structure; Patterning the support material layer to form a second cavity and a support layer, wherein the second cavity penetrates the support layer; Bonding a carrier substrate on the support layer, wherein the carrier substrate covers the second cavity; The temporary substrate is removed.

18. The method for manufacturing a MEMS device according to claim 17, characterized in that: After bonding the bulk acoustic wave filter and the surface acoustic wave filter, the method further comprises: The surface acoustic wave filter forms a first electrical connection structure electrically connected to an external circuit, and the bulk acoustic wave filter forms a second electrical connection structure electrically connected to an external circuit; The method for forming the first electrical connection structure comprises: Forming a first interconnection hole by an etching process, wherein the first interconnection hole penetrates through one side of the carrier substrate and extends to the interdigital transducer of the surface acoustic wave filter; forming a first conductive interconnection layer in the first interconnection hole, wherein the first conductive interconnection layer covers an inner surface of the first interconnection hole; The method for forming the second electrical connection structure comprises: forming a second interconnection hole by etching, wherein the second interconnection hole penetrates through one side of the carrier substrate and extends to the first electrode outside the effective resonance region of the piezoelectric stack; A second conductive interconnection layer is formed in the second interconnection hole, and the second conductive interconnection layer covers an inner surface of the second interconnection hole.

19. The method for manufacturing a MEMS device according to claim 18, characterized in that: After forming the first electrical connection structure and the second electrical connection structure, forming an interconnection line on the surface of the carrier substrate, the interconnection line is electrically connected to an external circuit, and the first conductive interconnection layer and the second conductive interconnection layer are electrically connected to the interconnection line; The first conductive interconnect layer includes a first plug, and the second conductive interconnect layer includes a second plug.

20. The method for manufacturing a MEMS device according to claim 12, characterized in that: The material of the first structure layer includes any one of a photolithographic organic curable film, silicon oxide, silicon oxynitride or silicon nitride.

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