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; a near-surface layer of the support substrate close to the first surface is an absorbing layer; the absorbing layer is a porous structure, and the pore diameter of the porous structure is below 1 nm. The bonding substrate provided by the application can make the longitudinal leakage energy of the elastic wave be transmitted and consumed in the absorbing layer, so that the stray signal cannot be reflected back to the device surface, thereby effectively absorbing the longitudinal leakage energy of the elastic wave device, reducing the body wave reflection and solving the stray signal of the elastic wave device.

Description

TECHNICAL FIELD

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

[0002] As a resonator or a band-pass filter, an 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. However, the ordinary thin film type filter is sensitive to temperature changes, and after a long time of power loading, frequency drift and performance degradation easily occur, and because of the limited frequency, it is difficult to meet the high frequency requirements proposed in the 5G communication era. Therefore, with the continuous development of technology, thin film filters made of composite substrates, such as temperature compensated SAW (TC-SAW) and the like, are continuously proposed, and the composite substrate thereof is generally a bonded sheet of a piezoelectric layer + support substrate structure. Among them, the piezoelectric layer is lithium tantalate or lithium niobate material, and the support substrate is a high acoustic velocity material such as Si, sapphire, SiC, etc.

[0003] In an ideal model, such as the energy of the surface acoustic wave should be concentrated as much as possible on the surface of the piezoelectric layer (within <1λ depth) to propagate, but in actual use, some specific designs such as the design of using Y42°LT material as the piezoelectric layer, there is a phenomenon of longitudinal leakage energy producing leakage wave, which is usually easy to produce spurious signals due to the body wave reflection of the support substrate, ultimately affecting the performance of the device and cannot be widely used. Therefore, reducing the spurious signals of the filter made based on the bonded sheet substrate structure is an important issue at present. SUMMARY

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

[0005] In order to solve the above technical problems, the first aspect of the present application provides a bonded substrate, comprising:

[0006] A support substrate having a first surface and a second surface opposite to the first surface; the near-surface layer of the support substrate close to the first surface is an absorbing layer;

[0007] The absorbing layer is a porous structure, and the pore diameter of the porous structure is less than or equal to 1 nm.

[0008] In a more preferred embodiment, the thickness of the absorbing layer is 0.1λ-10λ, and the λ is the wavelength of the elastic wave.

[0009] In a more preferred embodiment, a temperature compensation layer is provided on the first surface.

[0010] In a preferred embodiment, the thickness of the temperature compensation layer is 0.1λ-10λ, where λ is the wavelength of the elastic wave.

[0011] In a preferred embodiment, the near-surface layer of the support substrate near the first surface is a parallel patterned distribution of wave-absorbing layers and non-wave-absorbing layers.

[0012] In a preferred embodiment, the wave-absorbing layers and non-wave-absorbing layers extend in strips along a first direction and are arranged in parallel and alternately along a second direction, where the first direction is arranged transversely to the second direction.

[0013] In a preferred embodiment, the width of each strip-extended wave-absorbing layer is 0.1λ-λ; and / or the width of each strip-extended non-wave-absorbing layer is 0.1λ-λ, where λ is the wavelength of the elastic wave.

[0014] In a preferred embodiment, the porous structure is formed by implanting ions into the support substrate and performing an annealing process.

[0015] A second aspect of the present application provides an elastic wave device, comprising the bonding substrate as described above, a piezoelectric substrate formed on the bonding substrate, and an elastic wave component disposed on the piezoelectric substrate.

[0016] A third aspect of the present application provides a module, comprising the elastic wave device as described above.

[0017] Other features and advantages of the present application will be set forth in the descriptions below, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in 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 below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort. 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.

[0019] Figures 1 to 4 is a flow chart of the manufacturing method of the bonding substrate of the first embodiment of the present application;

[0020] Figure 5 is a cross-sectional TEM image of the support substrate of the first embodiment of the present application before annealing;

[0021] Figure 6 is a cross-sectional TEM image of the thick annealed support substrate of the first embodiment of the present application;

[0022] Figures 7 to 8 is a flowchart of the manufacturing method of the bonded substrate of the second embodiment of the present application;

[0023] Figures 9 to 14 is a flowchart of the manufacturing method of the bonded substrate of the third embodiment of the present application;

[0024] Figures 15 to 16 is a flowchart of the manufacturing method of the bonded substrate of the fourth embodiment of the present application;

[0025] Figure 17 is a structural diagram of the elastic wave device of the fifth embodiment of the present application;

[0026] Figure 18 is a partial plan view of the elastic wave device of the fifth embodiment of the present application;

[0027] Figure 19 is a cross-sectional view of the module including the elastic wave device of the sixth embodiment of the present application.

[0028] Reference Signs:

[0029] 10, support substrate; 10a, first surface; 10b, second surface; 2, patterned mask; 20, ion implantation layer; 30, wave-absorbing layer; 40, non-wave-absorbing layer; 50, temperature compensation layer; 60, piezoelectric substrate; 70, elastic wave component; 80, wiring electrode; 100, module; 110, elastic wave device; 111, inductor; 117, encapsulation portion; 130, wiring substrate; 131, external connection terminal. DETAILED DESCRIPTION

[0030] 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; as long as there is no conflict, the technical features in the different embodiments of the present application can be combined with each other; based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0031] In the description of the present application, it should be noted that all the terms (including technical terms and scientific terms) used by 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 cannot be understood as a limitation on the present application; it should be further understood that the terms used by 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 otherwise defined in the present application.

[0032] The technical solutions of the present application are further described and explained below through specific embodiments. However, the protection scope of the present application is not limited thereto.

[0033] Figure 4 is a structural schematic diagram of a bonded substrate provided by the first embodiment of the present application;

[0034] Please refer to Figure 4 In the first embodiment, the bonded substrate comprises a support substrate 10, a wave-absorbing layer 30 and a piezoelectric substrate 60.

[0035] The support substrate 10 is preferably made of a high sound speed material, and the sound speed of the high sound speed material is greater than the sound speed of the piezoelectric substrate. Specifically, the support substrate 10 is made of a high sound speed material, so that the support substrate 10 not only plays a supporting role, but also transmits signals as a high sound speed 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 the figure, 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 wave-absorbing layer 30 in the near-surface layer close to the first surface 10a; the wave-absorbing layer 30 is a porous structure, and the pore diameter of the porous structure is less than or equal to 1 nm. Therefore, based on the pore diameter range, a large number of small cavities are formed in the support substrate 10, and the longitudinal leakage energy of the elastic wave is transmitted and consumed therein, so that the stray signal cannot be reflected back to the device surface, thereby effectively absorbing the longitudinal leakage energy of the elastic wave device and reducing the body wave reflection to solve the stray signal problem of the elastic wave device.

[0036] In some embodiments, the thickness of the wave-absorbing layer 30 is 0.1λ to 10λ, that is, it can be understood that the thickness from the first surface 10a to a depth of 0.1λ to 10λ is the wave-absorbing layer 30, and the λ is the wavelength of the elastic wave. Based on this thickness, the size requirement of the device can be better adapted, and the stray signal problem of the elastic wave device can be effectively solved.

[0037] Please refer to Figure 6The bonding substrate provided by the second embodiment of the present application is different from the first embodiment in that a temperature compensation layer 50 is arranged on the first surface 10a of the support substrate 10, and a piezoelectric substrate 60 is arranged on the temperature compensation layer 50. The material of the temperature compensation layer 50 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. Preferably, the thickness of the temperature compensation layer is 0.1λ-10λ, and λ is the wavelength of the elastic wave.

[0038] Please refer to Figures 1-4 The method for preparing the bonding substrate of the first embodiment of the present application comprises the following steps:

[0039] Step 1, as shown in 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 bonding the support substrate and the piezoelectric substrate later.

[0040] Step 2, as shown in 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.

[0041] 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 thickness of the ion implantation layer 20. The ions are generally selected from gas ions, such as nitrogen ions, hydrogen ions, etc.

[0042] Step 3, as shown in Figure 3As shown, annealing treatment forms a microwave absorbing layer 30, which has a porous structure. Specifically, the support substrate 10 in which the ion implantation layer 20 is formed is heated in step 2 by controlling the temperature gradient. In some embodiments of the present invention, the temperature slope of the heating is ≤1.3 (≤1.3℃ per minute), and the temperature is kept constant at 600℃~1000℃ for 0.1~8 hours. At this temperature, when ions pass through the ion implantation damage, they diffuse to the entire bonding surface area of ​​the hypersonic support substrate through which the ions pass, and gradually obtain enough energy to break free from the lattice structure and break the bonds formed between them, forming a certain number of small bubbles, thus transforming the ion implantation layer 20 into the microwave absorbing layer 30. These tiny bubbles, less than 1 nm in size, appear as numerous small cavities in the support substrate 10. The longitudinal leakage energy of the elastic wave is transmitted and dissipated within them, preventing stray signals from being reflected back to the device surface. Preferably, in the first embodiment, the temperature slope of the heating is 1 (increasing by 1°C per minute), and the annealing process is completed by holding the temperature at 900°C for 3 hours.

[0043] Step 4, Reference Figure 4 As shown, a high-velocity acoustic substrate 1 and a piezoelectric material substrate 2 are bonded together by a bonding method to form a composite substrate. The bonding method can include direct bonding, anodic bonding, low-temperature bonding, vacuum bonding, and plasma-enhanced bonding. Taking direct bonding as an example, after two hydrophilic wafers are brought close together, the naturally attached hydroxyl groups (OH-) on their surfaces attract each other through van der Waals forces (intermolecular forces) to form a bond. The bonding substrates are heated at ambient pressure by controlling the temperature gradient. According to the present invention, the temperature rise slope is ≤1.3 (≤1.3℃ per minute). Heating is carried out at 50℃ to 250℃ for a certain period of time. During this process, the hydroxyl groups (-OH) on the bonding surface generate oxygen bonds (-O-) through a chemical reaction, which significantly improves the bonding force of the bonding substrates. Preferably, before bonding, the piezoelectric substrate 60 is polished and cleaned to meet the conditions for subsequent bonding of the support substrate and the piezoelectric substrate.

[0044] Step 5: Polish the bonded piezoelectric substrate 60 to a suitable thickness using chemical mechanical polishing, ultimately obtaining the desired result. Figure 4 The bonding substrate shown.

[0045] In detail, in the first embodiment, two sapphire substrates (500 μm thick) are selected as support substrates 10. After polishing and cleaning, the surfaces meet the bonding conditions. Nitrogen ions are 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 ions per substrate. 13 i ons / cm 2 The injection depth was 170nm.

[0046] Then, each is heated with a temperature slope of 1℃ per minute, and is kept at 900℃ for 3 hours. It can be seen from the comparison of the TEM results that: Figure 5 The red box shows that the ion implantation layer before annealing is uneven, Figure 6 The red box shows that the wave-absorbing layer after annealing is uniform), After annealing, the bonding surface of the sapphire substrate has a uniformly distributed wave-absorbing layer, and the size of the small bubbles is less than 1 nm. The total thickness of the wave-absorbing layer is about 170 nm.

[0047] In some embodiments, with reference to Figures 7-8 the embodiments of the first embodiment, between step 3 and step 4, a temperature compensation layer 50 can be made on the first surface 10a of the support substrate 10 by spin coating, evaporation, magnetron sputtering, chemical vapor deposition, etc. The temperature compensation layer 50 is used to improve the frequency temperature coefficient (TCF) and suppress stray signals, and finally obtain a bonded substrate as shown in Figure 9 or Figure 11 .

[0048] Please refer to Figure 14 the bonded substrate shown in the third embodiment provided by the present application, which comprises a support substrate 10, a wave-absorbing layer 30 and a piezoelectric substrate 60; the support substrate 10 has a parallel patterned distribution of the wave-absorbing layer 30 and the non-wave-absorbing layer 40 in the near-surface layer close to the first surface 10a. Specifically, in this embodiment, the top view of the support substrate 10 is shown in (B) of Figure 13 , and the side view is shown in (A) of Figure 13 , the wave-absorbing layer 30 and the non-wave-absorbing layer 40 extend in the form of strips along the first direction (for example, the x-axis direction) and are arranged in parallel and alternately along the second direction (for example, the y-axis direction), and the first direction and the second direction are arranged in a cross manner. This structure design can further increase the ability to suppress noise and improve the performance of the device; the non-wave-absorbing layer 40 can be directly composed of high sound speed material of the support substrate 10 in this embodiment, or can be formed by other functional material layer.

[0049] In some embodiments, the width of each strip-shaped wave-absorbing layer 30 is 0.1λ-λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above; and / or the width of each strip-shaped non-low sound speed layer 40 is 0.1λ-λ, which can be 0.1λ, 0.3λ, 0.5λ, 0.7λ, or a point value between any two of the above, and the λ is the wavelength of the elastic wave.

[0050] Based on the foregoing embodiments, on the basis of the third embodiment, with reference to Figure 16As shown, a temperature compensation layer 50 can also be provided on the first surface 10a of the support substrate 10 to improve the temperature coefficient of frequency (TCF) and suppress stray signals, thereby improving the performance of the device.

[0051] Please refer to Figures 9-14 , a method for preparing the bonded substrate of the third embodiment of the present application is provided, comprising the following steps:

[0052] Step 1, refer to Figure 9 As shown, 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.

[0053] Step 2, refer to Figure 10 As shown, 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 to form a parallel patterned distribution of the wave-absorbing layer 30 and the non-low sound speed layer 32 after ion implantation; specifically, a long strip-shaped mask with a line width of 0.1λ-λ can be formed on the support substrate 10 by dry etching or wet etching, i.e. the patterned mask 2.

[0054] Step 3, refer to Figure 11 As shown, ion implantation forms 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; as Figure X As shown, part of the ions are blocked by the patterned mask 2 and cannot be implanted into the support substrate 10, resulting in a strip-shaped ion implantation structure after ion implantation, and then the patterned mask 2 is washed away.

[0055] Figure 13 Step 4 annealing treatment as shown Figure 14 The mechanical polishing of step 5 is the same as the method of the first embodiment described above, and will not be described in detail here.

[0056] Referring to Figures 15-16 The fourth embodiment of the preparation process is shown, which is based on the structure of the third embodiment to provide a temperature compensation layer 50 to improve its performance, the specific steps can be referred to the foregoing, and will not be described in detail.

[0057] Please refer to Figure 17 The elastic wave device provided by the fifth embodiment of the present application is shown, which comprises a bonded substrate, a piezoelectric substrate 60, and an elastic wave component 70.

[0058] 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 wave absorbing layer 30 in a near-surface layer close to the first surface 10a; the wave absorbing layer 30 is a porous structure with a pore diameter of 1 nm or less; the support substrate can be the one disclosed in the first to fourth embodiments;

[0059] a piezoelectric substrate 60 disposed on the support substrate, the piezoelectric substrate 60 preferably has a thickness of 100 μm to 500 μm, and the piezoelectric substrate 60 can be made of LiNbO3 or LiTaO3; alternatively, the piezoelectric substrate 60 can be made of a piezoelectric material such as AlN, ZnO, PZT, quartz, etc.

[0060] an elastic wave component 70 disposed on the piezoelectric substrate 60;

[0061] a wiring electrode 80 disposed on the piezoelectric substrate 60 and connected to the elastic wave component 70;

[0062] The elastic wave component 70 includes an interdigital transducer (IDT) 70a and a reflector 70b formed on the piezoelectric substrate 60. The interdigital transducer 70a includes a pair of comb electrodes 70c disposed opposite to each other. The comb electrodes 70c each have a plurality of electrode fingers 70d and a bus bar 70e connected to the electrode fingers 70d. The reflector 70b is disposed on both sides of the interdigital transducer 70a. Figure 18 The elastic wave component 70 includes an interdigital transducer (IDT) 70a and a reflector 70b formed on the piezoelectric substrate 60. The interdigital transducer 70a includes a pair of comb electrodes 70c disposed opposite to each other. The comb electrodes 70c each have a plurality of electrode fingers 70d and a bus bar 70e connected to the electrode fingers 70d. The reflector 70b is disposed on both sides of the interdigital transducer 70a.

[0063] The wiring electrode 80 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, etc. or an alloy containing at least one of them can be used. They can be disposed by sputtering or evaporation. The wiring electrode 80 disposed on the piezoelectric substrate 60 and connected to the elastic wave component 70 allows the elastic wave component 70 to be electrically connected to the input terminal In, the output terminal Out and the ground terminal GND.

[0064] Based on the fifth embodiment and referring to the foregoing embodiments, the thickness of the absorbing layer 30 is 0.1λ to 10λ, which can be understood as the absorbing layer 30 extending from the first surface 10a to a depth of 0.1λ to 10λ, where λ is the wavelength of the elastic wave. Based on this thickness, it can better adapt to the size requirements of the device and effectively solve the problem of stray signals in the elastic wave device.

[0065] Based on the fifth embodiment and referring to the foregoing embodiments, a temperature compensation layer 50 can be provided on the first surface 10a to improve the temperature coefficient of frequency (TCF) and suppress spurious signals, thereby further improving the performance of the device. Preferably, the thickness of the temperature compensation layer is 0.1λ to 10λ, where λ is the wavelength of the elastic wave.

[0066] Based on the fifth embodiment and referring to the foregoing embodiments, the near-surface layer of the support substrate 10 near the first surface 10a is a parallel patterned distribution of absorbing layers 30 and non-absorbing layers 40, which further enhances the ability to suppress noise, thereby improving the performance of the device; preferably, the absorbing layers and non-absorbing layers extend in strips along a first direction and are arranged alternately in parallel along a second direction, with the first direction and the second direction intersecting; preferably, the width of each strip-shaped absorbing layer 30 is 0.1λ to λ; and / or the width of each strip-shaped non-absorbing layer 40 is 0.1λ to λ, where λ is the wavelength of the elastic wave.

[0067] Figure 19 This is a cross-sectional view of module 100 in the sixth embodiment of the present invention. Figure 19 As shown, the elastic wave device 110 is provided on the main surface of the wiring board 130. The elastic wave device 110 can be, for example, the elastic wave device described in the ninth embodiment. The wiring board 130 includes a plurality of external connection terminals 131. The external connection terminals 131 can be mounted to the main printed circuit board of a predetermined mobile communication terminal.

[0068] An inductor 111 is provided on the main surface of the wiring board 130 to achieve impedance matching. The inductor 111 may be an integrated passive device (IPD). The module 100 seals multiple electronic components, including the elastic wave device 110, through a package 117.

[0069] The wiring board 130 contains an integrated circuit component (IC). The integrated circuit component (IC) includes a switching circuit and a low-noise amplifier, which are not shown in the figure.

[0070] 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 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 shall understand that the content not mentioned in a claim shall not be regarded as a limitation to the claim.

[0071] Although the terms such as support substrate, first surface, second surface, patterned mask, ion implantation layer, wave-absorbing layer, non-wave-absorbing layer, temperature compensation layer, piezoelectric substrate, elastic wave component, wiring electrode, etc. are used more frequently herein, the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the present application; it is against the spirit of the present application to interpret them 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-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0072] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and 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, comprising: The application relates to an elastic wave device, comprising: a support substrate having a first surface and a second surface opposite to the first surface; a near-surface layer of the support substrate close to the first surface is an absorbing layer; the absorbing layer is a porous structure, the pore diameter of the porous structure is below 1 nm, the thickness of the absorbing layer is 0.1 lambda to 10 lambda, and the lambda is the wavelength of an elastic wave.

2. The bonded substrate of claim 1, wherein: a temperature compensation layer is arranged on the first surface.

3. The bonded substrate of Claim 2, wherein: the thickness of the temperature compensation layer is 0.1 lambda to 10 lambda, and the lambda is the wavelength of an elastic wave.

4. The bonded substrate of Claim 1, wherein: the near-surface layer of the support substrate close to the first surface is an absorbing layer and a non-absorbing layer distributed in parallel patterns.

5. The bonded substrate of Claim 1, wherein: the absorbing layer and the non-absorbing layer extend in a strip shape along a first direction and are arranged in parallel and alternately along a second direction, and the first direction is arranged crosswise to the second direction.

6. The bonded substrate of Claim 1, wherein: the width of each strip-shaped extending absorbing layer is 0.1 lambda to lambda; and / or the width of each strip-shaped extending non-absorbing layer is 0.1 lambda to lambda, and the lambda is the wavelength of an elastic wave.

7. The bonded substrate of Claim 1, wherein: the porous structure is formed by injecting ions into the support substrate and performing annealing treatment.

8. An elastic wave device characterized by comprising: the application further relates to a piezoelectric substrate formed on the bonded substrate and an elastic wave component arranged on the piezoelectric substrate.

9. A module comprising the elastic wave device of claim 8.

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