Bonding substrate, elastic wave device, and module

Abstract

The application relates to the technical field of semiconductor devices, in particular to a bonding substrate, an elastic wave device and a module. The bonding substrate comprises a support substrate with a first surface and a second surface opposite to the first surface; the support substrate has a low sound velocity layer in a near-surface layer close to the first surface; the low sound velocity layer is a porous structure, and the pore diameter of the porous structure is greater than or equal to 5 nm and less than or equal to 200 nm. The bonding substrate provided by the application can concentrate the surface acoustic wave energy near the surface of the piezoelectric thin film layer, limit the energy leakage of the surface acoustic wave to the substrate, obtain a higher quality factor Q, improve the SAW characteristics and reduce the loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, 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 material forming an elastic wave resonator is bonded to a support substrate to form a thin film type filter. The thin film type filter can improve a mechanical quality factor (Q) and an electromechanical coupling coefficient. Some researches use an acoustic reflection film to avoid sound wave leakage to a bulk direction, and solve the problem of energy leakage by arranging a Bragg reflection layer of high acoustic impedance reflection layers and low acoustic impedance reflection layers alternately under a piezoelectric material substrate.

[0003] However, this raises a new problem. Generally, the material of the low acoustic impedance reflection layer is mostly silicon dioxide SiO2, and the material of the high acoustic impedance reflection layer is a metal, such as molybdenum, platinum, tungsten, etc. However, when the material of the high acoustic impedance reflection layer is a metal, a parasitic capacitance is generated between the interdigital electrode and the high acoustic impedance reflection layer, which affects the performance of the device, and the preparation steps are complex, which is difficult to improve the production efficiency of the device and reduce the production cost. Therefore, a simple and easy-to-use substrate structure is still needed to solve the problem of acoustic energy leakage. SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art, and provides a bonding substrate, a preparation method of the bonding substrate and an elastic wave device.

[0005] To solve the above technical problems, the first aspect of the present application provides a bonding substrate, comprising:

[0006] a support substrate having a first surface and a second surface opposite to the first surface; the support substrate has a low acoustic velocity layer in a near-surface layer close to the first surface;

[0007] The low acoustic velocity layer is a porous structure, and the pore diameter of the porous structure is greater than or equal to 5 nm and less than or equal to 200 nm.

[0008] In a preferred embodiment, the support substrate has a Bragg reflection layer in the near-surface layer close to the first surface, and the Bragg reflection layer has alternating low acoustic velocity layers and high acoustic velocity material layers.

[0009] In a preferred embodiment, the thickness of the low acoustic velocity layer is 0.1λ-λ, the thickness of the high acoustic velocity material layer is 0.1λ-λ, and the λ is the wavelength of the elastic wave; and / or the total thickness of the Bragg reflection layer is 0.1λ-10λ, and the λ is the wavelength of the elastic wave.

[0010] In a preferred embodiment, the thickness of the low-velocity layer is greater at a greater distance from the first surface.

[0011] In a preferred embodiment, the Bragg reflection layer includes 2-10 layers of the low-velocity layer and 2-10 layers of the high-velocity material layer.

[0012] In a preferred embodiment, a temperature compensation layer is provided on the first surface.

[0013] In a preferred embodiment, the total thickness of the temperature compensation layer and the Bragg reflection layer is 0.1λ-10λ, where λ is the wavelength of the elastic wave.

[0014] In a preferred embodiment, the support substrate has a low-velocity layer and a non-low-velocity layer in a parallel patterned distribution in a near-surface layer close to the first surface.

[0015] In a preferred embodiment, the low-velocity layer and the non-low-velocity layer extend in strips in a first direction and are arranged in parallel and alternately in a second direction, the first direction being arranged transversely to the second direction.

[0016] In a preferred embodiment, each strip-extended low-velocity layer has a width of 0.1λ-λ; and / or each strip-extended non-low-velocity layer has a width of 0.1λ-λ, where λ is the wavelength of the elastic wave.

[0017] In a preferred embodiment, the porous structure is formed by implanting ions into the support substrate and performing an annealing process.

[0018] A second aspect of the present application provides an elastic wave device including the bonded substrate as described above, a piezoelectric substrate formed on the bonded substrate, and an elastic wave component provided on the piezoelectric substrate.

[0019] A third aspect of the present application provides a module including the elastic wave device as described above.

[0020] 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 objectives and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the technical solutions of the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings; in the following description, the positional relationship described in the drawings is the direction of the components drawn in the drawings as the reference, unless otherwise specified.

[0022] Figures 1 to 4 The flow chart of the manufacturing method of the bonded substrate of the first embodiment of the present application;

[0023] Figures 5 to 7 The flow chart of the manufacturing method of the bonded substrate of the second embodiment of the present application;

[0024] Figures 8 to 9 The flow chart of the manufacturing method of the bonded substrate of the third embodiment of the present application;

[0025] Figures 10 to 11 The flow chart of the manufacturing method of the bonded substrate of the fourth embodiment of the present application;

[0026] Figure 12 The cross-sectional TEM image of the bonded substrate of the first embodiment of the present application;

[0027] Figures 13 to 18 The flow chart of the manufacturing method of the bonded substrate of the fifth embodiment of the present application;

[0028] Figures 19 to 22 The flow chart of the manufacturing method of the bonded substrate of the sixth embodiment of the present application;

[0029] Figures 23 to 24 The flow chart of the manufacturing method of the bonded substrate of the seventh embodiment of the present application;

[0030] Figures 25 to 26 The flow chart of the manufacturing method of the bonded substrate of the eighth embodiment of the present application;

[0031] Figure 27 The structural schematic diagram of the elastic wave device of the ninth embodiment of the present application;

[0032] Figure 28 The partial top view of the elastic wave device of the ninth embodiment of the present application;

[0033] Figure 29 The cross-sectional view of the module containing the elastic wave device of the tenth embodiment of the present application.

[0034] Reference signs:

[0035] 10, support substrate; 10a, first surface; 10b, second surface; 2, patterned mask; 20, ion implantation layer; 3, Bragg reflector layer; 30, low acoustic velocity layer; 31, layer of high acoustic velocity material; 32, non-low acoustic velocity layer; 40, temperature compensation layer; 50, piezoelectric substrate; 60, elastic wave assembly; 70, wiring electrode; 100, module; 110, elastic wave device; 111, inductor; 117, package portion; 130, wiring substrate; 131, external connection terminal. DETAILED DESCRIPTION

[0036] In order to make the objects, 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 with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application; and the technical features designed in different implementation manners of the present application described below can be combined with each other as long as there is no conflict. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] 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 meanings as those generally understood by a person of ordinary skill in the art 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 meanings as the meanings of these terms in the context of the present specification and the related art, and should not be understood in an idealized or overly formal sense, unless explicitly defined in the present application.

[0038] The technical solutions of the present application will be further described and explained through specific embodiments below. However, the protection scope of the present application is not limited thereto.

[0039] Figure 4 is a structural schematic diagram of a bonded substrate provided by the first embodiment of the present application;

[0040] Please refer to Figure 4 In the first embodiment, the bonded substrate includes a support substrate 10, a low acoustic velocity layer 30 and a piezoelectric substrate 50.

[0041] The support substrate 10 is preferably made of a high acoustic velocity material, which has a higher acoustic velocity than the piezoelectric substrate. Specifically, the support substrate 10 is made of a high acoustic velocity material, so that the support substrate 10 not only supports the piezoelectric substrate 50, but also transmits signals as a high acoustic velocity medium. The material of the support substrate 10 can be silicon carbide, aluminum oxide, aluminum nitride, sapphire, silicon nitride, silicon, quartz, diamond, spinel, magnesium oxide, or a suitable material thereof. The thickness of the support substrate 10 is preferably 100 μm to 1000 μm, such as 200 μm to 800 μm, or 300 μm to 700 μm. Figure 1 As shown in FIG. 1, the support substrate 10 has a first surface 10a and a second surface 10b opposite to the first surface 10a, and the support substrate 10 has a low acoustic velocity layer 30 in a near-surface layer close to the first surface 10a. The low acoustic velocity layer 30 has a porous structure with a pore diameter of 5 nm or more and 200 nm or less. Thus, the substrate material of the support substrate 10 is a high acoustic velocity region, and the porous structure with the pore diameter in the support substrate 10 is a low acoustic velocity region, thereby forming a Bragg reflection structure of high and low acoustic velocity regions. In this way, the energy of the elastic wave is concentrated on the surface of the piezoelectric substrate 50, and the energy of the elastic wave is effectively limited from leaking to the support substrate, thereby obtaining a higher quality factor Q, improving the characteristics of the elastic wave, and reducing the loss.

[0042] In some embodiments, the thickness of the low acoustic velocity layer is 0.1λ to λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above, and the thickness of the high acoustic velocity material layer is 0.1λ to λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above, and λ is the wavelength of the elastic wave. Preferably, the total thickness of the Bragg reflection layer 3 is 0.1λ to 10λ, and λ is the wavelength of the elastic wave. In the above thickness range, the size requirement of the device can be better met, and the energy of the elastic wave can be effectively limited on the surface of the piezoelectric substrate 50. More preferably, the general acoustic velocity of the high acoustic velocity region is more than 3 times the acoustic velocity of the low acoustic velocity region, so as to better meet the adaptability of the device.

[0043] Please refer to Figure 7 The support substrate 10, the Bragg reflection layer 3, and the piezoelectric substrate 50 are shown in the second embodiment of the present application.

[0044] Please refer to Figure 7As shown, the support substrate 10 has a first surface 10a and a second surface 10b opposite to the first surface 10a, and the support substrate 10 has a Bragg reflection layer 3 in a near-surface layer close to the first surface 10a; the Bragg reflection layer 3 has alternating low-velocity layers 30 and high-velocity material layers 31, at this time, the surface layer of the support substrate 10 has a high-velocity material layer 31 composed of a high-velocity support substrate material, and a low-velocity layer 30 with a porous structure; and the number of high-velocity material layers 31 in the support substrate 10 is ≥1, and the number of low-velocity layers is ≥1, thereby forming a low-velocity layer 30 with a porous structure in the support substrate 10, and the Bragg reflection structure of the high-velocity support substrate material as the high-velocity material layer 31 can effectively concentrate the energy of the elastic wave on the surface of the piezoelectric substrate 50, limit the leakage of the elastic wave energy to the support substrate, thereby obtaining a higher quality factor Q, improving the elastic wave characteristics, and reducing the loss;

[0045] In some preferred embodiments, the Bragg reflection layer 3 includes 2-10 low-velocity layers and 2-10 high-velocity material layers; it is worth noting that a single low-velocity layer with a porous structure in the Bragg reflection structure of the high- and low-velocity zones formed by the support substrate 10 is relatively insufficient in limiting the energy escaping from the piezoelectric substrate 50, and if the low-velocity layer with a porous structure and the high-velocity material layer have too many layers, the number of layers of the Bragg reflection layer 3 formed is too large, which easily affects the sound velocity of the support substrate, therefore, when the number of layers of each of them is between 2-10, a better performance of the elastic wave device can be achieved. Furthermore, preferably, the farther the low-velocity layer 30 is from the first surface 10a, the greater the thickness of the low-velocity layer 30, which can make it have a better limiting effect; in some embodiments, in terms of alternating low-velocity layers 30 and high-velocity material layers 31, the farther the low-velocity layer 30 and the high-velocity material layer 31 are from the first surface 10a, the greater the thickness of the low-velocity layer 30 and the high-velocity material layer 31; it should be noted that the high-velocity material layer 31 can be composed of the Bragg reflection layer 3 by adjusting the position of the low-velocity layer 30 in the support substrate 10, thereby cooperating with the high-velocity material layer 31 formed by the original support substrate 10, or it can be formed by other means to form the low-velocity layer 30 and the high-velocity material layer 31, such as forming the low-velocity layer 30 with a porous structure by invisible engraving.

[0046] Please refer to Figure 9The support substrate 10 of the third embodiment of the present application is different from the first embodiment in that a temperature compensation layer 40 is arranged on the first surface 10a of the support substrate 10, and a piezoelectric substrate 50 is arranged on the temperature compensation layer 40. The material of the temperature compensation layer 40 can be SiO2, etc. The structure of the support substrate 10 of the present application can improve the temperature coefficient of frequency (TCF) and suppress the stray signal, thereby further improving the performance of the device. For example Figure 11 The fourth embodiment of the present application is different from the second embodiment in that a temperature compensation layer 40 is arranged on the first surface 10a of the support substrate 10.

[0047] In some embodiments, the total thickness of the temperature compensation layer 40 and the Bragg reflection layer 3 is 0.1λ-10λ, where λ is the wavelength of the elastic wave. For example, the thickness of the temperature compensation layer 40 is 0.25λ, and the thickness of the Bragg reflection layer 3 is 0.5λ.

[0048] Referring to Figures 1-4 , a method for preparing the bonded substrate of the first embodiment of the present application is provided, which comprises the following steps:

[0049] Step 1, referring to Figure 1 , a support substrate 10 is provided, which has a first surface 10a and a second surface 10b opposite to the first surface 10a. Preferably, the support substrate 10 is polished and cleaned to meet the conditions for subsequent bonding of the support substrate and the piezoelectric substrate.

[0050] Step 2, referring to Figure 2 , an ion implantation layer 20 is formed in the near-surface layer of the support substrate 10 close to the first surface 10a by ion implantation. In this embodiment, nitrogen ions are implanted from the first surface 10a of the support substrate 10 by ion implantation to form an ion implantation layer 20.

[0051] It is worth noting that the thickness of the ion implantation layer 20 can be determined by the dose of ion implantation, and the distance from the first surface 10a can be determined by adjusting the implantation depth, i.e. controlling the distance between the ion implantation layer 20 and the first surface 10a, thereby controlling the thickness and depth of the ion implantation layer 20 formed by multiple implantations. The ions are generally selected from gas ions, such as nitrogen ions, hydrogen ions, etc. In some embodiments, the ion implantation includes single implantation (as shown in Figure 2 ) and multiple implantations (as shown in Figure 5In the second embodiment shown, a plurality of ion implantation layers 20 at different depths are formed in the near-surface layer of the support substrate 10 close to the first surface 10a by ion implantation, so that a plurality of Bragg reflection layers 3 with high and low sound velocities are formed without overlapping each other;

[0052] Step 3, referring to Figure 3 As shown, the annealing process forms a low sound velocity layer 30 with a porous structure; specifically, the support substrate 10 with the ion implantation layer 20 formed in step 2 is heated with a controlled temperature gradient; in some embodiments of the present application, the temperature gradient of the heating process is ≤1.3 (≤1.3℃ per minute), and the temperature is kept constant at 1200-1500℃ for 1-6 hours. This step can provide the ions in the ion implantation layer of the support substrate 10 with enough energy to break the bonds between them and form a porous structure with a pore diameter of 5-200nm. Figures 5-6 If multiple ion implantation processes are performed to form ion implantation layers 20 at different depths and with the same / different thicknesses, a plurality of low sound velocity layers 30 at different depths and with the same / different thicknesses can be obtained after the annealing process of the present application.

[0053] Step 4, referring to Figure 4 As shown, the support substrate 10 is bonded to the piezoelectric substrate 50 by bonding to form a composite substrate. The bonding method can be direct bonding, anodic bonding, low-temperature bonding, vacuum bonding, plasma-enhanced bonding, etc. For example, in the direct bonding method, the two wafers with hydrophilic surfaces are brought close to each other, and the hydroxyl groups (OH - ) naturally attached to the surfaces are attracted to each other by Van der Waals force (intermolecular force) to form a bonded body. The bonded substrate is heated under normal pressure by controlling the temperature gradient. In some embodiments of the present application, the temperature gradient of the heating process is ≤1.3 (≤1.3℃ per minute). The temperature is kept constant at 50-250℃ for a certain period of time. In this process, the hydroxyl groups (-OH) on the bonding surface generate oxygen bonds (-O-) through a chemical reaction, so that the bonding force of the bonded substrate is greatly improved. Preferably, before bonding, the piezoelectric substrate 50 is polished and cleaned to meet the conditions for bonding the support substrate and the piezoelectric substrate.

[0054] Step 5, the bonded piezoelectric substrate 50 is polished to a suitable thickness by chemical mechanical polishing, and finally a Figure 4 or Figure 7 bonded substrate as shown is obtained.

[0055] In detail, for the first embodiment, a sapphire substrate (500 μm thick) is selected as the support substrate 10. After polishing and cleaning, the surface meets the bonding conditions. A layer of nitrogen ions is implanted from the bonding surface of the sapphire substrate (i.e., the first surface 10a of the support substrate 10) using ion implantation, with an implantation dose of 8 × 10⁻⁶. 13 ions / cm 2 The implantation depth is 160nm;

[0056] Then, it was heated at a temperature gradient of 1°C per minute and held at 1400°C for 3 hours. (Reference) Figure 12 TEM results show that a low-velocity layer 30 with a porous structure has appeared on the bonding surface of the sapphire substrate. The adjacent high-velocity material layer 31 (i.e., the supporting substrate 10) can serve as a high-velocity region, forming the simplest Bragg reflection structure.

[0057] In some embodiments, refer to respectively Figures 8-9 and Figures 10-11 In an embodiment, between steps 3 and 4, a temperature compensation layer 40 can be formed on the first surface 10a of the support substrate 10 using methods such as spin coating, vapor deposition, magnetron sputtering, or chemical vapor deposition. This layer is used to improve the temperature coefficient of frequency (TCF) and suppress stray signals, ultimately achieving the desired result. Figure 9 or Figure 11 The bonding substrate shown.

[0058] Please refer to Figure 18 The bonding substrate shown in the fifth embodiment of the present invention includes: a support substrate 10, a low-velocity layer 30, and a piezoelectric substrate 50; the support substrate 10 has a near-surface layer close to the first surface 10a containing parallel patterned low-velocity layers 30 and non-low-velocity layers 32. Specifically, in this embodiment, the top view of the support substrate 10 is as follows: Figure 17 As shown in (B) in the figure, its side view is as follows Figure 17 As shown in (A), the low-velocity layer 30 and the non-low-velocity layer 32 extend in a strip along a first direction (e.g., the x-axis direction) and are arranged alternately in parallel along a second direction (e.g., the y-axis direction). The first direction and the second direction are intersected. This structural design can further enhance the ability to suppress noise, thereby improving the performance of the device. The non-low-velocity layer 32 can be formed using a high-velocity material, such as directly composed of the high-velocity material of the supporting substrate 10 in this embodiment, or it can be formed using other functional materials.

[0059] In some embodiments, each of the low acoustic velocity layer 30 has a width of 0.1λ to λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above; and / or each of the non-low acoustic velocity layer 32 has a width of 0.1λ to λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above, the λ being the wavelength of the elastic wave.

[0060] Based on the foregoing embodiments, on the basis of the fifth embodiment, a temperature compensation layer 40 can also be provided on the first surface 10a of the support substrate 10, which plays a role in improving the frequency temperature coefficient (TCF, temperature coefficient of frequency) and suppressing stray signals, thereby improving the performance of the device.

[0061] Referring to Figures 13-18 , a method for preparing the bonded substrate of the fifth embodiment of the present application is provided, comprising the following steps:

[0062] Step 1, referring to Figure 13 , a support substrate 10 is provided, which has a first surface 10a and a second surface 10b opposite to the first surface 10a; preferably, the support substrate 10 is polished and cleaned to meet the conditions for subsequent bonding of the support substrate and the piezoelectric substrate;

[0063] Step 2, referring to Figure 14 , a patterned mask 2 is formed on the support substrate 10, which has an opening exposing part of the first surface 10a of the support substrate 10, so as to form a parallel patterned distribution of low acoustic velocity layers 30 and non-low acoustic velocity layers 32 after ion implantation; specifically, a long strip-shaped mask with a line width of 0.1λ to λ, i.e. a patterned mask 2, can be formed on the support substrate 10 by dry etching or wet etching;

[0064] Step 3, referring to Figure 15 , ion implantation is performed to form an ion implantation layer 20 in the near-surface layer of the support substrate 10 close to the first surface 10a; in this embodiment, nitrogen ions are implanted from the first surface 10a of the support substrate 10 by ion implantation to form one or more ion implantation layers 20; as shown in Figure X , since part of the ions are blocked by the patterned mask 2 and cannot be implanted into the support substrate 10, the resulting overhead effect after ion implantation is a strip-shaped ion implantation structure, and then the patterned mask 2 is washed away.

[0065] The annealing treatment of step 4 and the mechanical polishing of step 5 are the same as the method of the foregoing first embodiment, and will not be described in detail here.

[0066] Based on the fifth embodiment, referring to the preparation flow of the sixth embodiment shown in Figures 19-22 Based on the fifth embodiment, referring to the preparation flow of the sixth embodiment shown in

[0067] Based on the fifth embodiment, referring to the preparation flow of the seventh embodiment shown in Figures 23-24 and the eighth embodiment shown in Figures 25-26 The seventh and eighth embodiments can also set a temperature compensation layer 40 for a single-layer or multi-layer low-velocity layer 30 patterned structure to improve its performance. The specific steps can refer to the foregoing content and will not be described in detail.

[0068] Please refer to Figure 27 The elastic wave device provided by the ninth embodiment of the present application comprises a bonding substrate, a piezoelectric substrate 50, and an elastic wave component 60.

[0069] The bonding substrate comprises a support substrate 10 having a first surface 10a and a second surface 10b opposite to the first surface 10a; the support substrate 10 has a low-velocity layer 30 in the near-surface layer close to the first surface 10a; the low-velocity layer 30 is a porous structure with a pore diameter of 5 nm or more and 200 nm or less; and the bonding substrate can be the bonding substrate disclosed in the first to eighth embodiments.

[0070] The piezoelectric substrate 50 is disposed on the bonding substrate, and the thickness of the piezoelectric substrate 50 is preferably 100 μm to 500 μm; the material of the piezoelectric substrate 50 can be LiNbO3 or LiTaO3; in addition, the material of the piezoelectric substrate 50 can also be composed of piezoelectric materials such as AlN, ZnO, PZT, quartz, etc.

[0071] The elastic wave component 60 is disposed on the piezoelectric substrate 50.

[0072] The wiring electrode 70 is disposed on the piezoelectric substrate 50 and connected to the elastic wave component 60.

[0073] The elastic wave component 60 comprises a finger-shaped electrode and a reflector formed on the piezoelectric substrate 50; the finger-shaped electrode comprises a pair of oppositely disposed comb-shaped electrodes, each of which has a plurality of electrode fingers and a bus bar connected to the electrode fingers; and the reflector is disposed on both sides of the finger-shaped electrode; more specifically, for example Figure 28As shown, the elastic wave component 60 includes an interdigital transducer (IDT) 60a for exciting an elastic surface wave and a reflector 60b formed on the piezoelectric substrate 50. The interdigital transducer 60a includes a pair of comb electrodes 60c arranged opposite to each other. The comb electrodes 60c each have a plurality of electrode fingers 60d and a bus bar 60e connected to the electrode fingers 60d. The reflector 60b is arranged on both sides of the interdigital transducer 60a.

[0074] The wiring electrode 70 and the interdigital transducer can be a single layer or a stack of multiple layers of metal material. Al, Pt, Cu, Au, Ti, Ni, Cr, W, Ag, Pd, Co, Mn, or an alloy containing at least one of them, or the like can be used. They can be arranged by sputtering or evaporation. The wiring electrode 70 connected to the elastic wave component 60 is arranged on the piezoelectric substrate 50, so that the elastic wave component 60 can be electrically connected to the wiring constituting the input terminal In, the output terminal Out, and the ground terminal GND.

[0075] On the basis of the ninth embodiment, with reference to the foregoing embodiments, the support substrate 10 has a Bragg reflection layer 3 in the near-surface layer close to the first surface 10a, and the Bragg reflection layer 3 has alternating low-velocity layers 30 and high-velocity material layers 31 to form a Bragg reflection structure in the support substrate 10 with the low-velocity layers 30 having a porous structure, and the high-velocity support substrate material is the high-velocity material layers 31. The Bragg reflection structure can effectively concentrate the energy of the elastic wave on the surface of the piezoelectric substrate 50, limit the leakage of the energy of the elastic wave to the support substrate, thereby obtaining a higher quality factor Q, improving the characteristics of the elastic wave, and reducing the loss. Preferably, the thickness of the low-velocity layer 30 is 0.1λ to λ, the thickness of the high-velocity material layer 31 is 0.1λ to λ, and the λ is the wavelength of the elastic wave; preferably, the total thickness of the Bragg reflection layer 3 is 0.1λ to 10λ, and the λ is the wavelength of the elastic wave.

[0076] On the basis of the ninth embodiment, with reference to the foregoing embodiments, a temperature compensation layer 40 can be provided on the first surface 10a to improve the frequency temperature coefficient (TCF, temperature coefficient of frequency) and suppress spurious signals, further improving the performance of the device.

[0077] On the basis of the ninth embodiment, with reference to the foregoing embodiments, the support substrate 10 has a low acoustic velocity layer 30 and a non-low acoustic velocity layer 32 in a near-surface layer close to the first surface 10a, which are distributed in a parallel pattern, to further increase the ability to suppress noise and improve the performance of the device. Preferably, the low acoustic velocity layer 30 and the non-low acoustic velocity layer 32 extend in a strip shape in a first direction and are arranged in parallel and alternately in a second direction, the first direction being arranged transversely to the second direction; preferably, each strip-shaped low acoustic velocity layer 30 has a width of 0.1λ to λ, and / or each strip-shaped non-low acoustic velocity layer 32 has a width of 0.1λ to λ, λ being the wavelength of the elastic wave.

[0078] Figure 29 is a sectional view of a module 100 according to a tenth embodiment of the present application. As shown in Figure 29 the elastic wave device 110 is provided on a main surface of a wiring substrate 130. The elastic wave device 110 can be, for example, the elastic wave device described in the ninth embodiment. The wiring substrate 130 includes a plurality of external connection terminals 131. The external connection terminals 131 can be mounted to a main printed circuit board of a predetermined mobile communication terminal.

[0079] An inductor 111 is provided on the main surface of the wiring substrate 130 for impedance matching. The inductor 111 can be an Integrated Passive Device (IPD). The module 100 seals a plurality of electronic parts including the elastic wave device 110 by a sealing portion 117.

[0080] An integrated circuit part IC is provided inside the wiring substrate 130. The integrated circuit part IC includes a switch circuit and a low noise amplifier, which are not shown in the figure.

[0081] In addition, those skilled in the art will understand that, although there are many problems in the prior art, each embodiment or technical solution of the present application can only be improved 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 should understand that what is not mentioned in a claim should not be regarded as a limitation on the claim.

[0082] Although the terms such as support substrate, first surface, second surface, patterned mask, ion implantation layer, Bragg reflector layer, low acoustic velocity layer, high acoustic velocity material layer, non-low acoustic velocity layer, temperature compensation layer, piezoelectric substrate, elastic wave component, wiring electrode, etc. are used more frequently in this document, the possibility of using other terms is not excluded. These terms are used only for the convenience of describing and explaining the essence of the present application; they are not interpreted as any kind of additional limitation; the terms "first", "second", etc. (if present) in the specification and claims of the embodiments of the present application and the above-described drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A bonded substrate, comprising: The support substrate has a first surface and a second surface opposite to the first surface. The Bragg reflection layer has a low acoustic velocity layer and a high acoustic velocity material layer. The low acoustic velocity layer has a porous structure with a pore diameter of 5 nm or more and 200 nm or less. The Bragg reflection layer has an alternating low acoustic velocity layer and high acoustic velocity material layer.

2. The bonded substrate of claim 1, wherein: The thickness of the low acoustic velocity layer is 0.1λ to λ, the thickness of the high acoustic velocity material layer is 0.1λ to λ, and the total thickness of the Bragg reflection layer is 0.1λ to 10λ, where λ is the wavelength of an elastic wave.

3. The bonded substrate of Claim 1, wherein: The thickness of the low acoustic velocity layer increases with the distance from the first surface.

4. The bonded substrate of Claim 2, wherein: The Bragg reflection layer includes 2 to 10 low acoustic velocity layers and 2 to 10 high acoustic velocity material layers.

5. The bonded substrate of Claim 2, wherein: A temperature compensation layer is provided on the first surface.

6. The bonded substrate of Claim 1, wherein: The total thickness of the temperature compensation layer and the Bragg reflection layer is 0.1λ to 10λ, where λ is the wavelength of an elastic wave.

7. The bonded substrate of Claim 6, wherein: The support substrate has a near-surface layer with a parallel patterned distribution of low acoustic velocity layers and non-low acoustic velocity layers near the first surface.

8. The bonded substrate of Claim 1, wherein: The low acoustic velocity layers and non-low acoustic velocity layers extend in strips along a first direction and are arranged in parallel and alternately along a second direction, and the first direction and the second direction are arranged in a cross manner.

9. The bonded substrate of Claim 8, wherein: The width of each strip-shaped low acoustic velocity layer is 0.1λ to λ, and / or the width of each strip-shaped non-low acoustic velocity layer is 0.1λ to λ, where λ is the wavelength of an elastic wave.

10. The bonded substrate of Claim 9, wherein: The porous structure is formed by ion implantation into the support substrate and annealing treatment.

11. The bonded substrate of Claim 1, wherein: The elastic wave module includes the bonded substrate, a piezoelectric substrate formed on the bonded substrate, and an elastic wave component disposed on the piezoelectric substrate.

12. An elastic wave device characterized by comprising:

13. A module including the elastic wave device of claim 12. ​

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