Bonding substrate, elastic wave device, and module

Abstract

The application relates to the technical field of filters, in particular to a bonding substrate, an elastic wave device and a module. The bonding substrate comprises a support substrate with opposite first and second surfaces; a dielectric layer arranged on the first surface of the support substrate; and a piezoelectric layer arranged on the side of the dielectric layer away from the support substrate. The dielectric layer comprises a low sound velocity layer and a high sound velocity layer, the high sound velocity layer is arranged on the first surface, and the low sound velocity layer is arranged on the side of the high sound velocity layer away from the support substrate. A polycrystal-amorphous mixed area is arranged between the support substrate and the low sound velocity layer. The bonding substrate provided by the application has the polycrystal-amorphous mixed area arranged between the support substrate and the low sound velocity layer, the polycrystal and amorphous structures in the polycrystal-amorphous mixed area scatter and reflect high-order spurs, the cavity hole does not need to be introduced, the bonding substrate has high-order spur suppression capability, the structure is simple, the filtering effect is good, the preparation cost is low, and the application value is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter, in particular to a bonding substrate, an elastic wave device and a module. BACKGROUND

[0002] As a resonator or a band-pass filter, the elastic wave device is widely used. It is known that a piezoelectric substrate forming an elastic wave resonator is bonded to a support substrate through a dielectric layer to form a thin film type filter. The thin film type filter can improve the mechanical quality factor (Q) and the electromechanical coupling coefficient, however, due to the influence of the high-order spurious waves reflected from the interface of the dielectric layer and the support substrate on the electrical performance of the filter, the improvement of the performance of the thin film type filter is limited.

[0003] In order to eliminate or suppress the high-order spurious waves, a known method is to introduce a cavity hole between the dielectric layer and the support substrate to scatter the spurious waves through the cavity hole.

[0004] However, the scheme of introducing a hole in the interface of the dielectric layer and the support substrate is complicated in steps, difficult in processing technology, and high in cost, which limits the practical application of this scheme. Therefore, how to simply obtain a composite substrate with spurious wave suppression effect has become the focus of research. SUMMARY

[0005] In order to solve the problems of the existing filter bonding substrate, such as difficult preparation of cavity holes and high cost, the present application provides a bonding substrate, comprising

[0006] The support substrate has opposite first and second surfaces.

[0007] The dielectric layer is arranged on the first surface of the support substrate.

[0008] The piezoelectric layer is arranged on the side of the dielectric layer away from the support substrate.

[0009] The dielectric layer includes a low sound speed layer and a high sound speed layer, the high sound speed layer is arranged on the first surface, and the low sound speed layer is arranged on the side of the high sound speed layer away from the support substrate.

[0010] A polycrystalline-amorphous mixed area is provided between the support substrate and the low sound speed layer.

[0011] In an embodiment, the polycrystalline-amorphous mixed area is provided inside the high sound speed layer.

[0012] In an embodiment, the polycrystalline-amorphous mixed area is provided at the junction of the high sound speed layer and the support substrate.

[0013] The present application also provides a bonding substrate, comprising

[0014] The support substrate has opposite first and second surfaces.

[0015] a medium layer disposed on the first surface of the support substrate.

[0016] a piezoelectric layer disposed on a side of the medium layer distal from the support substrate.

[0017] wherein the medium layer comprises a low acoustic velocity layer disposed on the first surface,

[0018] The support substrate is made of a high acoustic velocity material. The support substrate has a polycrystalline-amorphous mixed region inside.

[0019] In an embodiment, the piezoelectric layer has an IDT electrode disposed on a side distal from the medium layer. The polycrystalline-amorphous mixed region has a projection on the piezoelectric layer that covers at least the IDT electrode.

[0020] In an embodiment, the polycrystalline region accounts for 0-70% of the polycrystalline-amorphous mixed region. Preferably, the polycrystalline region accounts for 30-50% of the polycrystalline-amorphous mixed region.

[0021] In an embodiment, the polycrystalline unit cell has a unit cell radius ranging from 0.1 μm to 5 μm. Preferably, the polycrystalline unit cell has a unit cell radius ranging from 1 μm to 3 μm.

[0022] In an embodiment, the polycrystalline-amorphous mixed region is obtained by laser engraving after the medium layer is bonded to the support substrate.

[0023] In an embodiment, the laser engraving uses a laser power of 2000-3000 W, a heating time of 20-100 μs, and a laser frequency of 20-60 kHz.

[0024] In an embodiment, the polycrystalline-amorphous mixed region has a thickness of 0.2 μm to 10 μm. Preferably, the polycrystalline-amorphous mixed region has a thickness of 2 μm to 6 μm.

[0025] In an embodiment, the polycrystalline-amorphous mixed region has a thickness to total thickness ratio of 0.02-0.1:1. The total thickness of the medium layer is the sum of the thickness of the low acoustic velocity layer and the thickness of the high acoustic velocity layer.

[0026] In an embodiment, the polycrystalline-amorphous mixed region has a thickness to total thickness ratio of 0.02-0.1:1. The total thickness of the medium layer is the sum of the thickness of the medium layer and the thickness of the support substrate.

[0027] The present application also provides an elastic wave device, comprising a bonding substrate and an elastic wave assembly disposed on the bonding substrate.

[0028] wherein the bonding substrate comprises

[0029] a support substrate having opposite first and second surfaces.

[0030] a medium layer disposed on the first surface of the support substrate.

[0031] a piezoelectric layer disposed on a side of the dielectric layer distal from the support substrate.

[0032] The dielectric layer includes a low acoustic velocity layer and a high acoustic velocity layer, the high acoustic velocity layer is disposed on the first surface, and the low acoustic velocity layer is disposed on a side of the high acoustic velocity layer distal from the support substrate. A polycrystalline-amorphous mixed region is disposed between the support substrate and the low acoustic velocity layer. An elastic wave assembly is disposed on a surface of the piezoelectric layer.

[0033] In an embodiment, the polycrystalline-amorphous mixed region is disposed inside the high acoustic velocity layer.

[0034] In an embodiment, the polycrystalline-amorphous mixed region is disposed at an interface between the high acoustic velocity layer and the support substrate.

[0035] The application also provides an elastic wave device, including a bonding substrate, and an elastic wave assembly disposed on the bonding substrate. The bonding substrate includes

[0036] a support substrate having opposite first and second surfaces.

[0037] a dielectric layer disposed on the first surface of the support substrate.

[0038] a piezoelectric layer disposed on a side of the dielectric layer distal from the support substrate.

[0039] The dielectric layer includes a low acoustic velocity layer, the low acoustic velocity layer is disposed on the first surface, and the support substrate is made of a high acoustic velocity material. A polycrystalline-amorphous mixed region is disposed inside the support substrate. An elastic wave assembly is disposed on a surface of the piezoelectric layer.

[0040] In an embodiment, the elastic wave assembly includes an IDT electrode disposed on a side of the piezoelectric layer distal from the dielectric layer. A projection of the polycrystalline-amorphous mixed region on the piezoelectric layer covers at least the IDT electrode.

[0041] In an embodiment, a proportion of the polycrystalline region in the polycrystalline-amorphous mixed region is 0-70%. Preferably, it is 30-50%.

[0042] In an embodiment, a unit cell radius of the polycrystalline unit cell in the polycrystalline-amorphous mixed region ranges from 0.1 μm to 5 μm. Preferably, it ranges from 1 μm to 3 μm.

[0043] In an embodiment, the polycrystalline-amorphous mixed region is obtained by laser engraving after bonding of the dielectric layer and the support substrate.

[0044] In an embodiment, the laser engraving uses a laser power of 2000-3000 W, a heating time of 20-100 μs, and a laser frequency of 20-60 KHz.

[0045] In an embodiment, the polycrystalline-amorphous mixed region has a thickness of 0.2-10 μm. Preferably, the thickness is 2-6 μm.

[0046] In an embodiment, the ratio of the thickness of the polycrystalline-amorphous mixed region to the total thickness of the dielectric layer is 0.02-0.1:1. The total thickness of the dielectric layer is the sum of the thickness of the low-velocity layer and the thickness of the high-velocity layer.

[0047] In an embodiment, the ratio of the thickness of the polycrystalline-amorphous mixed region to the total thickness of the dielectric layer is 0.02-0.1:1. The total thickness of the dielectric layer is the sum of the thickness of the low-velocity layer and the thickness of the high-velocity layer.

[0048] The present application provides a module comprising the bonded substrate as described in any of the above or the elastic wave device as described in any of the above.

[0049] Based on the above, compared with the prior art, the bonded substrate provided by the present application has the polycrystalline-amorphous mixed region between the support substrate and the low-velocity layer, the polycrystalline and amorphous structures inside the polycrystalline-amorphous mixed region scatter and reflect the high-order spurs, no cavity hole is needed, and the bonded substrate has high-order spur suppression capability. The structure is simple, the filtering effect is good, the preparation cost is low, and the bonded substrate has good application value.

[0050] Other features and advantages of the present application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor; in the following description, the positional relationship described in the drawings is the direction of the components drawn in the drawings as the reference.

[0052] Figure 1 FIG. 1 is a structural schematic diagram of an embodiment of the present application;

[0053] Figure 2 FIG. 2 is a structural schematic diagram of another embodiment of the present application;

[0054] Figure 3 FIG. 3 is a structural schematic diagram of another embodiment of the present application;

[0055] Figure 4 FIG. 4 is a structural schematic diagram of another embodiment of the present application;

[0056] Figure 5 Structure diagram of another embodiment of the present application;

[0057] Figure 6 Top view of an embodiment of the present application;

[0058] Figure 7 Structure diagram of an embodiment of the present application;

[0059] Figure 8 Structure diagram of an embodiment of the present application;

[0060] Figure 9 Structure diagram of an embodiment of the present application; Figure 1 Process flow diagram of an embodiment;

[0061] Figure 10 Process flow diagram of an embodiment; Figure 5 Process flow diagram of an embodiment;

[0062] Figure 11 Structure diagram of a module provided by the present application.

[0063] Reference signs:

[0064] 100 joint substrate 110 support substrate 120 medium layer

[0065] 121 low acoustic velocity layer 122 high acoustic velocity layer 130 piezoelectric layer

[0066] 140 polycrystalline-amorphous mixed region 200 elastic wave device 210 elastic wave assembly

[0067] 211 IDT electrode 300 module DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. The technical features designed in different embodiments of the present application can be combined with each other as long as they do not conflict with each other. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0069] In the description of the present application, it should be noted that all the terms (including technical terms and scientific terms) used in the present application have the same meaning as that generally understood by the ordinary skilled person in the field to which the present application belongs, and should not be understood as a limitation of the present application; it should be further understood that the terms used in the present application should be understood as having the same meaning as the terms in the context of the present application and the related field, and should not be understood in an idealized or overly formal sense, unless defined explicitly in the present application.

[0070] As shown in Figures 1 to 3 The present application provides a bonded substrate 100, comprising a support substrate 110, a dielectric layer 120 and a piezoelectric layer 130.

[0071] The support substrate 110 has opposite first and second surfaces. The dielectric layer 120 is arranged on the first surface of the support substrate 110. The piezoelectric layer 130 is arranged on the side of the dielectric layer 120 away from the support substrate 110.

[0072] The dielectric layer 120 comprises a low acoustic velocity layer 121 and a high acoustic velocity layer 122, the high acoustic velocity layer 122 is arranged on the first surface, and the low acoustic velocity layer 121 is arranged on the side of the high acoustic velocity layer 122 away from the support substrate 110.

[0073] A polycrystalline-amorphous mixed region 140 is provided between the support substrate 110 and the low acoustic velocity layer 121.

[0074] In actual application, the polycrystalline-amorphous mixed region 140 between the support substrate 110 and the low acoustic velocity layer 121 scatters and reflects high-order spurs through the polycrystalline and amorphous structures inside, without the need to introduce cavity holes, so that the bonded substrate 100 obtains high-order spur suppression capability.

[0075] Specifically, the polycrystalline region and the amorphous region in the polycrystalline-amorphous mixed region 140 suppress noise by scattering high-order spurs. However, according to the principle that the scattering of waves by an obstacle is the largest when the wavelength is similar to the size of the object, when the polycrystalline region and the amorphous region exist alone, they can only scatter spurs of different wavelengths in a small range. When the polycrystalline-amorphous mixed region 140 is formed, it can scatter spurs of different wavelengths in a large range. And in production, the mixing ratio of the two can be controlled to scatter the main spurs of the filter, so as to obtain a filter with almost no high-order noise.

[0076] Specifically, the low-velocity layer 121 is made of a low-velocity material, which can be any of the following: silicon oxide, glass, silicon oxynitride, tantalum oxide, or a compound in which fluorine, carbon, or boron is added to silicon oxide, or a material in which any of these materials is the main component. The high-velocity layer 122 is made of a high-velocity material, which can be any of the following: aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, a DLC film or diamond, a material in which any of these materials is the main component, or a material in which a mixture of any of these materials is the main component. The piezoelectric layer 130 is made of at least one material selected from the group consisting of LiTaO3, LiNbO3, ZnO, AlN, and quartz. The support substrate 110 is preferably made of a high-velocity material. Specifically, the support substrate 110 is made of a high-velocity material, so that the support substrate 110 functions as a support and also transmits signals as a high-velocity medium. The support substrate 110 can be a substrate made of a material selected from the group consisting of, for example, silicon carbide, aluminum oxide, aluminum nitride, sapphire, silicon nitride, silicon, quartz, diamond, cordierite, mullite, talc, forsterite, spinel, and magnesium oxide. The materials of the various layers can be selected by a person skilled in the art as needed.

[0077] Preferably, as shown in FIG. 1, the polycrystalline-amorphous mixed region 140 is disposed inside the high-velocity layer 122. Specifically, disposing the polycrystalline-amorphous mixed region 140 inside the high-velocity layer 122 can reduce the influence of the polycrystalline-amorphous mixed region 140 on the bonding surface of the high-velocity layer 122 and the support substrate 100 during the preparation of the polycrystalline-amorphous mixed region 140, thereby avoiding a decrease in the strength of the bonding surface of the support substrate 100. Figure 2

[0078] Further, the polycrystalline-amorphous mixed region 140 disposed inside the high-velocity layer 122 is 5-50 μm away from the piezoelectric layer 130. Specifically, the thickness of the high-velocity layer 122 is 50-150 μm. Specifically, the thickness of the high-velocity layer 122 refers to the initial thickness of the high-velocity layer 122 before the polycrystalline-amorphous mixed region 140 is disposed.

[0079] Preferably, as shown in FIG. 1, the polycrystalline-amorphous mixed region 140 is disposed inside the high-velocity layer 122. Specifically, disposing the polycrystalline-amorphous mixed region 140 inside the high-velocity layer 122 can reduce the influence of the polycrystalline-amorphous mixed region 140 on the bonding surface of the high-velocity layer 122 and the support substrate 100 during the preparation of the polycrystalline-amorphous mixed region 140, thereby avoiding a decrease in the strength of the bonding surface of the support substrate 100. Figure 1

[0080] As shown in FIG. 1, the polycrystalline-amorphous mixed region 140 is disposed at the interface between the high-velocity layer 122 and the support substrate 110. Specifically, disposing the polycrystalline-amorphous mixed region 140 at the interface can increase the scattering of sound waves by using the polycrystalline-amorphous mixed region 140, thereby achieving better noise suppression for the support substrate 100. Figure 4 Figure 5 ​​​As shown, the application also provides a bonded substrate 100, comprising a support substrate 110, a dielectric layer 120 and a piezoelectric layer 130. The support substrate 110 has opposite first and second surfaces. The dielectric layer 120 is arranged on the first surface of the support substrate 110. The piezoelectric layer 130 is arranged on the side of the dielectric layer 120 away from the support substrate 110.

[0081] The dielectric layer 120 comprises a low acoustic velocity layer 121 arranged on the first surface of the support substrate 110,

[0082] The support substrate 110 is made of a high acoustic velocity material. The polycrystalline-amorphous mixed region 140 is arranged inside the support substrate 110. Specifically, arranging the polycrystalline-amorphous mixed region 140 inside the support substrate 110 can simplify the manufacturing process of the bonded substrate 100, thereby saving costs. Preferably, the distance between the polycrystalline-amorphous mixed region 140 and the first surface of the support substrate 110 is in the range of 0-100 μm.

[0083] Specifically, the support substrate 110 is made of a high acoustic velocity material, so that the support substrate 110 can support the bonded substrate 100 and transmit signals as a high acoustic velocity medium. Such a design uses the support substrate 110 as a high acoustic velocity layer 122, thereby simplifying the manufacturing process of the bonded substrate 100 and saving production costs. Moreover, using a high acoustic velocity material for the support substrate 110 can increase the K value and Q value of the final product.

[0084] Preferably, as shown, Figures 1 to 6 As shown, the piezoelectric layer 130 further comprises an IDT electrode 211 on the side away from the dielectric layer 120. The projection of the polycrystalline-amorphous mixed region 140 on the piezoelectric layer 130 covers at least the IDT electrode 211. Specifically, the polycrystalline-amorphous mixed region 140 covers at least the IDT electrode 211, so that the polycrystalline-amorphous mixed region 140 does not need to be arranged on the whole surface, thereby further reducing costs.

[0085] In an embodiment, the proportion of the polycrystalline region in the polycrystalline-amorphous mixed region 140 is 0-70%. Preferably, the proportion of the polycrystalline region in the polycrystalline-amorphous mixed region 140 is 30%-50%. By controlling the proportion of the polycrystalline region, the ability of the bonded substrate 100 to suppress spurs can be adjusted, thereby enhancing the spur suppression performance and flexibility of the bonded substrate 100.

[0086] Preferably, the cell radius of the polycrystalline cell in the polycrystalline-amorphous mixed region 140 is in the range of 0.1 μm-5 μm. Preferably, the cell radius of the polycrystalline cell in the polycrystalline-amorphous mixed region 140 is in the range of 1 μm-3 μm. Specifically, controlling the cell radius of the polycrystalline cell can enhance the reflection and scattering ability of spurs, thereby further improving the spur suppression effect.

[0087] In an embodiment, the polycrystalline-amorphous mixed region 140 is obtained by laser engraving after the medium layer 120 is bonded with the support substrate 110. Specifically, the laser engraving after bonding can effectively avoid affecting the bonding strength of the support substrate 110 and the medium layer 120, thereby ensuring that the performance of the bonded substrate 100 as a whole is not affected. Further, the polycrystalline-amorphous mixed region 140 is prepared by laser engraving, which theoretically enables the polycrystalline-amorphous mixed region 140 to be processed at any depth inside the bonded substrate 100. In actual production, the polycrystalline-amorphous mixed region 140 can be obtained at the best noise suppression position of any bonded substrate 100 through production adjustment, which can be more targeted for processing. At the same time, the laser engraving method can control the laser heating time and power parameters to obtain the best noise suppression polycrystalline-amorphous mixed region 140 thickness, polycrystalline proportion, and polycrystalline cell size, which has strong flexibility in regulation. At the same time, the laser engraving method can solve the problem that some excellent substrate materials are not easy to form amorphous and polycrystalline, thereby expanding the material selection range of the bonded substrate 100.

[0088] Further, the laser power used in laser engraving is 2000-3000W, the heating time is 20-100us, and the laser frequency is 20-60KHz. By controlling the laser parameters used in laser engraving, the formation of the polycrystalline-amorphous mixed region 140 can be ensured, and the polycrystalline and amorphous structures in the polycrystalline-amorphous mixed region 140 can be influenced to enhance the noise suppression ability of the bonded substrate 100.

[0089] In an embodiment, the thickness of the polycrystalline-amorphous mixed region 140 is 0.2-10μm. Preferably, the thickness of the polycrystalline-amorphous mixed region 140 is 2-6μm.

[0090] Preferably, when the high sound velocity layer 122 is provided, the ratio of the thickness of the polycrystalline-amorphous mixed region 140 to the total thickness of the medium layer 120 is 0.02-0.1:1. The total thickness of the medium layer 120 is the sum of the thickness of the low sound velocity layer 121 and the thickness of the high sound velocity layer 122. If the thickness ratio of the polycrystalline-amorphous mixed region 140 is too low, i.e., the polycrystalline-amorphous mixed region 140 is too thin, its reflection and scattering of noise are not obvious, and the overall suppression effect of the bonded substrate 100 is poor. If the thickness ratio of the polycrystalline-amorphous mixed region 140 is too high, it will lead to a significant increase in the difficulty of laser engraving and preparation cost. Specifically, the thickness of the high sound velocity layer 122 refers to the initial thickness of the high sound velocity layer 122 without the polycrystalline-amorphous mixed region 140.

[0091] Preferably, when the support substrate 110 is made of high acoustic velocity material, the ratio of the thickness of the polycrystalline-amorphous mixed region 140 to the total thickness of the medium is 0.02-0.1:1, and the total thickness of the medium is the sum of the thickness of the medium layer 120 and the thickness of the support substrate 110. Specifically, the thickness of the support substrate 110 refers to the initial thickness of the support substrate 110 without the polycrystalline-amorphous mixed region 140.

[0092] As shown in Figure 6 and Figure 7 The present application also provides an elastic wave device 200, comprising a bonding substrate 100, and an elastic wave assembly 210 disposed on the bonding substrate 100.

[0093] The bonding substrate 100 comprises

[0094] a support substrate 110 having opposite first and second surfaces.

[0095] a medium layer 120 disposed on the first surface of the support substrate 110.

[0096] a piezoelectric layer 130 disposed on the side of the medium layer 120 away from the support substrate 110.

[0097] Preferably, the medium layer 120 comprises a low acoustic velocity layer 121 and a high acoustic velocity layer 122, the high acoustic velocity layer 122 is disposed on the first surface, and the low acoustic velocity layer 121 is disposed on the side of the high acoustic velocity layer 122 away from the support substrate 110. A polycrystalline-amorphous mixed region 140 is disposed between the support substrate 110 and the low acoustic velocity layer 121. The elastic wave assembly 210 is disposed on the surface of the piezoelectric layer 130.

[0098] Specifically, the elastic wave assembly 210 comprises an interdigital transducer layer and a wiring layer, the interdigital transducer layer comprises IDT electrodes 211 and bus bars, and the wiring layer comprises a connecting portion and a pad portion. Those skilled in the art can set the interdigital transducer layer and the wiring layer according to actual needs.

[0099] Preferably, the polycrystalline-amorphous mixed region 140 is disposed inside the high acoustic velocity layer 122. Specifically, disposing the polycrystalline-amorphous mixed region 140 inside the high acoustic velocity layer 122 can reduce the influence of the polycrystalline-amorphous mixed region 140 on the bonding surface of the high acoustic velocity layer 122 and the support substrate 100 during preparation, thereby avoiding the decrease in the strength of the bonding surface of the bonding substrate 100, and further avoiding the influence on the overall strength of the elastic wave device 200.

[0100] Further, the polycrystalline-amorphous mixed region 140 disposed inside the high acoustic velocity layer 122 is 5-50 μm away from the piezoelectric layer 130. Specifically, the thickness of the high acoustic velocity layer 122 is 50-150 μm. Specifically, the thickness of the high acoustic velocity layer 122 refers to the initial thickness of the high acoustic velocity layer 122 without the polycrystalline-amorphous mixed region 140.

[0101] Preferably, the polycrystalline-amorphous mixed region 140 is arranged at the interface between the high acoustic velocity layer 122 and the support substrate 110. Arranging the polycrystalline-amorphous mixed region 140 at the interface can increase the scattering effect of the acoustic wave by using the polycrystalline-amorphous mixed material, so that the bonding substrate 100 has a better spurious wave suppression effect and the elastic wave device 200 has a better performance.

[0102] As shown in Figure 6 and Figure 8 , the present application also provides an elastic wave device 200, which comprises a bonding substrate 100 and an elastic wave assembly 210 arranged on the bonding substrate 100. The bonding substrate 100 comprises

[0103] a support substrate 110 having opposite first and second surfaces.

[0104] a dielectric layer 120 arranged on the first surface of the support substrate 110.

[0105] a piezoelectric layer 130 arranged on the side of the dielectric layer 120 away from the support substrate 110.

[0106] Preferably, the dielectric layer 120 comprises a low acoustic velocity layer 121 arranged on the first surface, and the support substrate 110 is made of a high acoustic velocity material. The polycrystalline-amorphous mixed region 140 is arranged in the support substrate 110. The elastic wave assembly 210 is arranged on the surface of the piezoelectric layer 130. Specifically, arranging the polycrystalline-amorphous mixed region 140 in the support substrate 110 can simplify the manufacturing process of the bonding substrate 100, thereby saving costs. Preferably, the distance between the polycrystalline-amorphous mixed region 140 and the first surface of the support substrate 110 is in the range of 0-100 μm. At the same time, the support substrate 110 is made of a high acoustic velocity material, so that the support substrate 110 not only supports the bonding substrate 100 but also transmits signals as a high acoustic velocity medium. Such a design uses the support substrate 110 as the high acoustic velocity layer 122, thereby simplifying the manufacturing process of the bonding substrate 100 and saving production costs. Moreover, using the high acoustic velocity material for the support substrate 110 can increase the K value and Q value of the elastic wave device 200.

[0107] Specifically, the elastic wave assembly 210 comprises an interdigital transducer layer and a wiring layer. The interdigital transducer layer comprises IDT electrodes 211 and bus bars, and the wiring layer comprises a connecting portion and a pad portion. Those skilled in the art can arrange the interdigital transducer layer and the wiring layer according to actual needs.

[0108] Preferably, as shown in Figures 6 to 8As shown, the elastic wave assembly 210 includes an IDT electrode 211 disposed on a side of the piezoelectric layer 130 distal to the dielectric layer 120. The polycrystalline-amorphous mixed region 140 has a projection on the piezoelectric layer 130 that covers at least the IDT electrode 211.

[0109] In an embodiment, the polycrystalline regions in the polycrystalline-amorphous mixed region 140 have a proportion of 0-70%. Preferably, the polycrystalline regions in the polycrystalline-amorphous mixed region 140 have a proportion of 30-50%.

[0110] In an embodiment, the polycrystalline cells in the polycrystalline-amorphous mixed region 140 have a cell radius in a range of 0.1-5 μm. Preferably, the polycrystalline cells in the polycrystalline-amorphous mixed region 140 have a cell radius in a range of 1-3 μm.

[0111] In an embodiment, the polycrystalline-amorphous mixed region 140 is obtained by laser ablation after the dielectric layer 120 is bonded to the support substrate 110.

[0112] In an embodiment, the laser ablation uses a laser power of 2000-3000 W, a heating time of 20-100 μs, and a laser frequency of 20-60 kHz.

[0113] In an embodiment, the polycrystalline-amorphous mixed region 140 has a thickness of 0.2-10 μm. Preferably, the polycrystalline-amorphous mixed region 140 has a thickness of 2-6 μm.

[0114] In an embodiment, the polycrystalline-amorphous mixed region 140 has a thickness to total dielectric layer 120 thickness ratio of 0.02-0.1:1. The total dielectric layer 120 thickness is the sum of the thickness of the low acoustic velocity layer 121 and the thickness of the high acoustic velocity layer 122. Specifically, the thickness of the high acoustic velocity layer 122 refers to the initial thickness of the high acoustic velocity layer 122 without the polycrystalline-amorphous mixed region 140.

[0115] In an embodiment, the polycrystalline-amorphous mixed region 140 has a thickness to total dielectric layer 120 thickness ratio of 0.02-0.1:1. The total dielectric layer 120 thickness is the sum of the thickness of the low acoustic velocity layer 121 and the thickness of the high acoustic velocity layer 122. Specifically, the thickness of the high acoustic velocity layer 122 refers to the initial thickness of the high acoustic velocity layer 122 without the polycrystalline-amorphous mixed region 140.

[0116] In an embodiment, as shown in FIG. 2A, the elastic wave device 200 includes a support substrate 110, a dielectric layer 120, and an elastic wave assembly 210. The dielectric layer 120 is disposed on the support substrate 110. The elastic wave assembly 210 is disposed on the dielectric layer 120. Specifically, the elastic wave assembly 210 includes an IDT electrode 211. Figure 1 、 Figure 6 、 Figure 7 and Figure 9 As shown, the elastic wave assembly 210 includes an IDT electrode 211 disposed on a side of the piezoelectric layer 130 distal to the dielectric layer 120. The polycrystalline-amorphous mixed region 140 has a projection on the piezoelectric layer 130 that covers at least the IDT electrode 211.

[0117] The bonding substrate 100 includes a support substrate 110, a medium layer 120, and a piezoelectric layer 130. The support substrate 110 has opposite first and second surfaces. The medium layer 120 is arranged on the first surface of the support substrate 110. The piezoelectric layer 130 is arranged on the side of the medium layer 120 away from the support substrate 110.

[0118] Further, the medium layer 120 includes a low acoustic velocity layer 121 and a high acoustic velocity layer 122, the high acoustic velocity layer 122 is arranged on the first surface, and the low acoustic velocity layer 121 is arranged on the side of the high acoustic velocity layer 122 away from the support substrate 110. A polycrystalline-amorphous mixed region 140 is provided between the support substrate 110 and the high acoustic velocity layer 122. The IDT electrode 211 is arranged on the surface of the piezoelectric layer 130.

[0119] The preparation process is that, after bonding the piezoelectric layer 130 and the medium layer 120, the piezoelectric layer 130 is bonded with the support substrate 110. After the whole bonding is completed, the region between the support substrate 110 and the high acoustic velocity layer 122 is laser engraved by using laser, and the polycrystalline-amorphous mixed region 140 is obtained. Finally, the IDT electrode 211 is arranged on the surface of the piezoelectric layer 130.

[0120] In an embodiment, as shown in Figure 5 , Figure 6 , Figure 8 and Figure 10 , the elastic wave device 200 includes the bonding substrate 100 and an elastic wave assembly 210. The elastic wave assembly 210 is provided on the bonding substrate 100. Specifically, the elastic wave assembly 210 includes the IDT electrode 211.

[0121] The bonding substrate 100 includes a support substrate 110, a medium layer 120, and a piezoelectric layer 130. The support substrate 110 has opposite first and second surfaces. The medium layer 120 is arranged on the first surface of the support substrate 110. The piezoelectric layer 130 is arranged on the side of the medium layer 120 away from the support substrate 110.

[0122] The support substrate 110 is made of a high acoustic velocity material, so that the support substrate 110 is used as a high acoustic velocity medium while supporting. The medium layer 120 includes a low acoustic velocity layer 121, which is arranged on the first surface. The support substrate 110 is internally provided with a polycrystalline-amorphous mixed region 140, and the projection of the polycrystalline-amorphous mixed region 140 on the piezoelectric layer 130 coincides with the IDT electrode 211.

[0123] As shown in Figure 11 , the present application provides a module 300, which includes the bonding substrate 100 as described above or the elastic wave device 200 as described above.

[0124] In addition, those skilled in the art shall understand that, although there are many problems in the prior art, each embodiment or technical solution of the present application can only improve in one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or background art at the same time. Those skilled in the art shall understand that the content not mentioned in a claim shall not be regarded as a limitation to the claim.

[0125] Although the terms such as bonding substrate, support substrate, dielectric layer and piezoelectric layer are used more in this paper, the possibility of using other terms is not excluded. The use of these terms is only to facilitate the description and explanation of the essence of the present application; any additional limitation by interpreting them is contrary to the spirit of the present application; the terms "first", "second", etc. (if any) in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0126] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art shall understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A bonded substrate, characterized by: The application relates to a piezoelectric layer and a piezoelectric device. A support substrate has opposite first and second surfaces; A medium layer is arranged on the first surface of the support substrate; A piezoelectric layer is arranged on the side of the medium layer away from the support substrate; The medium layer comprises a low-speed layer and a high-speed layer, the high-speed layer is arranged on the first surface, and the low-speed layer is arranged on the side of the high-speed layer away from the support substrate; A polycrystal-amorphous mixed area is arranged between the support substrate and the low-speed layer; The cell radius of the polycrystal cell in the polycrystal-amorphous mixed area ranges from 0.1 to 5 micrometers.

2. A bonded substrate, characterized by: The application relates to a piezoelectric layer and a piezoelectric device. A support substrate has opposite first and second surfaces; A medium layer is arranged on the first surface of the support substrate; A piezoelectric layer is arranged on the side of the medium layer away from the support substrate; The medium layer comprises a low-speed layer and a high-speed layer, the high-speed layer is arranged on the first surface, and the low-speed layer is arranged on the side of the high-speed layer away from the support substrate; A polycrystal-amorphous mixed area is arranged between the support substrate and the low-speed layer; The ratio of the thickness of the polycrystal-amorphous mixed area to the total thickness of the medium layer is 0.02-0.1:1, and the total thickness of the medium layer is the sum of the thickness of the low-speed layer and the thickness of the high-speed layer.

3. The bonded substrate of Claim 1 or 2, wherein: The polycrystal-amorphous mixed area is arranged inside the high-speed layer.

4. The bonded substrate of Claim 1 or 2, wherein: The polycrystal-amorphous mixed area is arranged at the junction of the high-speed layer and the support substrate.

5. A bonded substrate, characterized by: The application relates to a piezoelectric layer and a piezoelectric device. A support substrate has opposite first and second surfaces; A medium layer is arranged on the first surface of the support substrate; A piezoelectric layer is arranged on the side of the medium layer away from the support substrate; The medium layer comprises a low-speed layer, and the low-speed layer is arranged on the first surface, The support substrate is made of a high-speed material, and a polycrystal-amorphous mixed area is arranged inside the support substrate; The cell radius of the polycrystal cell in the polycrystal-amorphous mixed area ranges from 0.1 to 5 micrometers.

6. A bonded substrate, characterized by: The application relates to a piezoelectric layer and a piezoelectric device. A support substrate has opposite first and second surfaces; A medium layer is arranged on the first surface of the support substrate; A piezoelectric layer is arranged on the side of the medium layer away from the support substrate; The medium layer comprises a low-speed layer, and the low-speed layer is arranged on the first surface, The support substrate is made of a high-speed material, and a polycrystal-amorphous mixed area is arranged inside the support substrate; The ratio of the thickness of the polycrystal-amorphous mixed area to the total thickness of the medium is 0.02-0.1:1, and the total thickness of the medium is the sum of the thickness of the medium layer and the thickness of the support substrate.

7. The bonded substrate of claim 1 or 2 or 5 or 6, wherein: An IDT electrode is arranged on the side of the piezoelectric layer away from the medium layer, and the projection of the polycrystal-amorphous mixed area on the piezoelectric layer covers at least the IDT electrode.

8. The bonded substrate of claim 1 or 2 or 5 or 6, wherein: The proportion of the polycrystal area in the polycrystal-amorphous mixed area is 0-70%.

9. The bonded substrate of Claim 1 or 2 or 5 or 6, wherein: The polycrystal-amorphous mixed area is obtained by laser burning after the medium layer is bonded with the support substrate.

10. The bonded substrate of claim 1 or 2 or 5 or 6, wherein: The thickness of the polycrystal-amorphous mixed area is 0.2-10 micrometers.

11. An elastic wave device characterized by: The application relates to a piezoelectric layer and a piezoelectric device. The elastic wave assembly is arranged on the surface of the piezoelectric layer of the bonding substrate.

12. The elastic wave device of claim 11, wherein: The polycrystal-amorphous mixed region has a thickness of 0.2-10 μm.

13. An elastic wave device comprising a bonding substrate, and an elastic wave assembly provided on the bonding substrate, characterized in that: The bonding substrate is the bonding substrate according to any one of claims 5-10, and the elastic wave assembly is arranged on the surface of the piezoelectric layer.

14. The elastic wave device of claim 11 or 13, wherein: The elastic wave assembly comprises an IDT electrode provided on the side of the piezoelectric layer away from the dielectric layer, and the projection of the polycrystal-amorphous mixed region on the piezoelectric layer covers at least the IDT electrode.

15. A module characterized by: The bonding substrate according to any one of claims 1-10 or the elastic wave device according to any one of claims 11-14.

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