Bonded body and bonded body manufacturing method

Abstract

A bonded body is provided with: a piezoelectric material substrate (11); a support substrate (13) bonded to the piezoelectric material substrate; and an outer peripheral processing part obtained by inclining the outer peripheral parts of the piezoelectric material substrate (11) and the support substrate (13) with respect to the main surface of the piezoelectric material substrate (11). The outer peripheral part includes a first inclined surface facing the piezoelectric material substrate 11, and a second inclined surface which is located on a surface extended from the first inclined surface toward the outer peripheral part and faces the support substrate 13. As a result, there is provided a bonded body in which there is no corner section formed in the outer peripheral section and cracking or cracking does not readily occur in the outer peripheral section in a subsequent step, and a method for manufacturing the bonded body.

Description

TECHNICAL FIELD

[0001] The present application relates to a bonded body, a method for manufacturing a bonded body. BACKGROUND

[0002] For the purpose of realizing a high-performance semiconductor element, for example, a structure in which a piezoelectric material substrate and a support substrate are bonded is investigated. In recent years, in order to realize a further high-performance device, a structure including an intermediate layer, a structure using a support substrate using a difficult-to-machine material are proposed. In order to realize the structure, it is necessary to bond the two substrates of the piezoelectric material substrate and the support substrate, but if the bonding of these substrates is performed, an unbonded region (unbonded portion) is generated in the outer peripheral portion. The unbonded portion is caused by the shape of the outer peripheral portion before the bonding of these substrates. This shape is called a sag or roll-off. And if the unbonded portion is generated in the outer peripheral portion, peeling is easily generated at the time of machining of the piezoelectric material. In addition, sometimes a chip is generated at the time of peeling, and the chip damages the piezoelectric material. In order to avoid this, a method of performing machining to remove the unbonded portion generated in the outer peripheral portion is proposed.

[0003] In Patent Literature 1, it is disclosed that a composite substrate is a substrate for an elastic wave device, which has a support substrate, a piezoelectric substrate, and a bonding layer that bonds the support substrate and the piezoelectric substrate. The composite substrate is formed with the piezoelectric substrate in such a manner that, when a face of the piezoelectric substrate on the side bonded to the support substrate is taken as a first face and a face on the opposite side of the first face is taken as a second face, if the first face is projected onto the second face in the vertical direction with respect to the second face, the first face falls inside the second face. That is, the outer peripheral face is formed so that if the outer peripheral side of the piezoelectric substrate is approached, the outer periphery becomes larger.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2011 / 013553 SUMMARY

[0007] However, in the conventional method, although it is possible to prevent the problem caused by the unbonded portion at the outer peripheral portion, the outer peripheral portion becomes a special shape that imparts a corner portion to the substrate. Therefore, sometimes cracking or a crack is generated in the outer peripheral portion in a subsequent process, resulting in a decrease in yield.

[0008] An object of the present application is to provide a bonded body in which a corner portion is not formed in the outer peripheral portion and cracking or a crack is not easily generated in the outer peripheral portion in a subsequent process, and a method for manufacturing a bonded body.

[0009] To address the aforementioned issues, the present invention provides a bonding body comprising: a piezoelectric material substrate; a support substrate bonded to the piezoelectric material substrate; and an outer peripheral processing portion formed by tilting the outer peripheral portions of the piezoelectric material substrate and the support substrate relative to the main surface of the piezoelectric material substrate. The outer peripheral processing portion includes: a first inclined surface facing the piezoelectric material substrate, and a second inclined surface located on a surface extending from the first inclined surface toward the outer peripheral portion and facing the support substrate.

[0010] In addition, the present invention provides a method for manufacturing a bonding body, which includes the following steps: a bonding step in which a piezoelectric material substrate and a support substrate are bonded; and a grinding step in which the outer periphery of the bonded piezoelectric material substrate and the support substrate are ground, the grinding step being performed to form an outer peripheral processing portion including: a first inclined surface that is inclined relative to the main surface of the piezoelectric material substrate and faces the piezoelectric material substrate, and a second inclined surface that is located on a surface extending from the first inclined surface toward the outer periphery and faces the support substrate.

[0011] Invention Effects

[0012] According to the present invention, a joint body without corners formed on the outer periphery and not prone to cracking or fissures on the outer periphery in subsequent processes, and a method for manufacturing the joint body are provided. Attached Figure Description

[0013] Figure 1 This is a diagram showing the assembly of this embodiment.

[0014] Figure 2 This is a flowchart illustrating the manufacturing method of the joint.

[0015] Figure 3 In the diagram, (A) to (E) show the targets... Figure 2 The diagram shows the status of each process step.

[0016] Figure 4 In the text, (A) to (D) are correct. Figure 2 The diagram illustrates steps 106 (grinding process) and 107 (sanding process).

[0017] Figure 5 In the diagrams, (A) to (B) are comparison diagrams showing the case where grinding was performed using the grinding process of this embodiment and the case where grinding was performed using conventional methods.

[0018] Figure 6 In the diagram, (A) to (D) are comparisons of the grinding and lapping processes before and after the grinding and lapping operations. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0020] <Explanation of the structure of the joint>

[0021] Figure 1 This is a diagram showing the assembly 1 of this embodiment.

[0022] The illustrated assembly 1 presents a structure in which the piezoelectric layer 11a, the dielectric layer 12, and the support substrate 13 are stacked in this order, starting from the top of the figure.

[0023] The piezoelectric layer 11a is a layer made of a piezoelectric material. The piezoelectric material is selected according to the application of the bonding agent 1. For example, the piezoelectric material is LiNbO3 (LN) or LiTaO3 (LT), but it is not limited to these. Suitable materials may include silicon (Si), gallium arsenide (GaAs), silicon carbide (SiC), gallium nitride (GaN), zinc oxide (ZnO), solid solution ceramic (PZT), etc.

[0024] The dielectric layer 12 is disposed below the piezoelectric layer 11a. In this embodiment, the dielectric layer 12 is mainly composed of SiO2. That is, the dielectric layer 12 can also be referred to as a SiO2 film or SiO2 layer.

[0025] The support substrate 13 serves as the support for the entire bonding body 1. Furthermore, the support substrate 13 is bonded to the piezoelectric layer 11a via the dielectric layer 12. Any suitable substrate can be used as the support substrate 13. The support substrate 13 can be made of a single crystal or a polycrystalline material. Alternatively, it can be made of metal.

[0026] The material constituting the support substrate 13 is preferably selected from the group consisting of silicon, silicon aluminum oxynitride ceramic, sapphire, cordierite, andalusite, glass, quartz, crystal, alumina, SUS, iron-nickel alloy (42 alloy), and brass. The thickness of the support substrate 13 is, for example, 0.2 to 1 mm, or any other suitable thickness may be used.

[0027] The silicon mentioned above can be monocrystalline silicon, polycrystalline silicon, or high-resistivity silicon. Additionally, the support substrate 13 can be SOI (Silicon on Insulator).

[0028] Typically, the aforementioned silicon-aluminum-oxygen-nitrogen ceramics are ceramics obtained by sintering a mixture of silicon nitride and aluminum oxide, for example, having a silicon content of 0.5%. 6－w Al w O w N 8－wThe composition is indicated by the formula. Specifically, the silicon-aluminum-oxygen-nitrogen ceramic has a composition obtained by mixing alumina into silicon nitride, where w represents the mixing ratio of alumina. w is preferably 0.5 or more and 4.0 or less.

[0029] Typically, the sapphire described above is a single crystal with an Al2O3 composition, and the alumina described above is a polycrystalline material with an Al2O3 composition. The alumina is preferably a transparent alumina.

[0030] Representatively, the cordierite mentioned above is a ceramic having a composition of 2MgO·2Al2O3·5SiO2, and the andalusite mentioned above is a ceramic having a composition in the range of 3Al2O3·2SiO2 to 2Al2O3·SiO2.

[0031] <Device>

[0032] The structure of the junction 1 shown in the figure can be used as the structure of various devices. Examples of such devices include: high-frequency devices, power semiconductors, semiconductor lasers, surface acoustic wave (SAW) filters, and thin-film piezoelectric MEMS (Micro Electro Mechanical Systems).

[0033] <Explanation of the manufacturing method of joint 1>

[0034] Next, the manufacturing method of the assembly 1 will be described.

[0035] Figure 2 This is a flowchart illustrating the manufacturing method of the assembly 1. Additionally, Figure 3 (A) to (E) in the diagram show the target Figure 2 The diagram shows the status of each process in steps 101 to 105.

[0036] First, a piezoelectric material substrate 11 is prepared, and a dielectric layer 12a is formed on the surface of the piezoelectric material substrate 11 (step 101). Next, a support substrate 13 is prepared, and a dielectric layer 12b is formed on the surface of the support substrate 13 (step 102). Through steps 101 and 102, dielectric layers 12a and 12b are formed on the surfaces of the piezoelectric material substrate 11 and the support substrate 13 (dielectric layer formation process: Figure 3 (A)). It should be noted that the order of steps 101 and 102 can be reversed, and in steps 101 and 102, dielectric layers 12a and 12b may not be formed on the surfaces of the piezoelectric material substrate 11 and the support substrate 13. In addition, here, "surface" refers to the main surface of the piezoelectric material substrate 11 and the support substrate 13, not the side surface.

[0037] Dielectric layers 12a and 12b are primarily composed of SiO2. Dielectric layers 12a and 12b are integrated through bonding in a subsequent process to form dielectric layer 12, which is primarily composed of SiO2. Dielectric layers 12a and 12b can be formed using reactive sputtering with a reactive sputtering apparatus. Specifically, a piezoelectric material substrate 11 or a support substrate 13 is disposed within the reactive sputtering apparatus. Furthermore, a target made of silicon (Si) is disposed within the reactive sputtering apparatus. Argon (Ar) gas and oxygen radicals are then introduced into the reactive sputtering apparatus. Using a sputtering power source, the silicon constituting the target is sputtered, forming a silicon film on the piezoelectric material substrate 11 or the support substrate 13. This film is then oxidized using oxygen radicals to form a silicon oxide (SiO2) film. Thus, dielectric layers 12a and 12b, primarily composed of SiO2, can be formed on the surface of the piezoelectric material substrate 11 or the support substrate 13.

[0038] It should be noted that dielectric layers 12a and 12b can also be polished to planarize them. This improves the bonding strength during subsequent bonding processes.

[0039] Next, the surfaces of dielectric layers 12a and 12b are activated using plasma (step 103: activation process). Figure 3 (B)). As a plasma, N2 plasma can be used. Therefore, as... Figure 3 As shown in (C), the SiO2 constituting dielectric layers 12a and 12b is activated to generate hydroxyl groups (OH groups) as hydrophilic functional groups. Therefore, this process can also be regarded as a hydrophilization process that hydrophilizes the surfaces of dielectric layers 12a and 12b using plasma.

[0040] Then, the surfaces of the dielectric layers 12a and 12b after the activation process are bonded together (step 104: bonding process). Figure 3 (D)). For example, the surfaces of dielectric layers 12a and 12b are brought into contact with each other and pressed with a predetermined pressure to form a bond. Thus, the piezoelectric material substrate 11 and the support substrate 13 are bonded by means of dielectric layers 12a and 12b.

[0041] It should be noted that in steps 101 and 102 above, when the piezoelectric material substrate 11 and the support substrate 13 are not provided with dielectric layers 12a and 12b, the following method can be used: The surfaces of the piezoelectric material substrate 11 and the support substrate 13 are irradiated for a predetermined time with a high-speed atomic beam (hereinafter referred to as FAB (Fast Atom Beam)) using an inactive gas such as Ar as the atomic source, to perform activation treatment. After the piezoelectric material substrate 11 and the support substrate 13 are activated, they are bonded in the same way as the bonding process described above.

[0042] Then, the bonded piezoelectric material substrate 11 and support substrate 13 are heated (step 105: heating process). Figure 3 (E)). For example, the bonded piezoelectric material substrate 11 and support substrate 13 are placed in a heating device such as an oven and heated at a predetermined temperature and time. Heating causes the hydroxyl groups generated on the surfaces of dielectric layers 12a and 12b to covalently bond. Furthermore, dielectric layers 12a and 12b are integrated to form dielectric layer 12. Thus, the piezoelectric material substrate 11 and support substrate 13 are firmly bonded by means of dielectric layer 12. Additionally, at this time, the reaction [Si-OH]+[OH+Si]→[Si-O-Si]+H2O occurs, generating water (H2O). This water is released outside the dielectric layer 12.

[0043] It should be noted that the heating process can also be regarded as: the process of annealing the joined piezoelectric material substrate 11 and support substrate 13 (annealing process).

[0044] Next, the piezoelectric material substrate 11 is ground into a thin film (step 106: grinding process). Thus, a thin film is formed. Figure 1 The piezoelectric layer 11a shown can be ground using known methods employing a grinding machine.

[0045] Then, the outer periphery of the piezoelectric material substrate 11 and the support substrate 13 is ground (step 107: grinding process). The grinding film can be pressed onto the edge of the outer periphery of the bonding body 1, and the bonding body 1 and the grinding film are rotated to perform grinding. Through the above process, the bonding body 1 can be manufactured.

[0046] The grinding and lapping processes described above will be explained in detail below.

[0047] Figure 4 (A) to (D) are correct. Figure 2 The diagram illustrates steps 106 (grinding process) and 107 (sanding process).

[0048] in, Figure 4 (A) shows the piezoelectric material substrate 11 (LiTaO3(LT) substrate in the example) and the support substrate 13 (Si substrate in the example) after bonding through steps 104 (bonding process) and 105 (heating process). It should be noted that, for ease of explanation, the case without dielectric layer 12 is shown here, although dielectric layer 12 may also be present.

[0049] Figure 4 Figure (B) shows the piezoelectric material substrate 11 and the support substrate 13 after grinding in step 106 (grinding process). As shown, the piezoelectric material substrate 11 is thinned by grinding to form a piezoelectric layer 11a.

[0050] Figure 4 (C) in the middle is... Figure 4 The diagram (B) further illustrates the state before the grinding process in step 107. This can be referred to as: before edge grinding (peripheral grinding) of the piezoelectric material substrate 11 and the support substrate 13. In this case, the unbonded portion X of the piezoelectric material substrate 11 and the support substrate 13 is 0.7 mm or more and 1.5 mm or less. Furthermore, in this embodiment, grinding is performed on the grinding surface P shown by the dashed line, and an outer peripheral processing portion R is formed on the outer periphery of the piezoelectric material substrate 11 and the support substrate 13, so that there is no unbonded portion X and the piezoelectric material substrate 11 (LiTaO3 (LT) substrate in the example) and the support substrate 13 (Si substrate in the example) are smoothly continuous. In fact, grinding is performed on the grinding surface P with a specified grinding angle and range of unbonded portion X. Specifically, in the grinding process, grinding is performed relative to the main surface H of the piezoelectric material substrate 11 and the support substrate 13 in such a way that a grinding surface P with an angle of 3.5° or more and 12.0° or less is formed. This can also be described as: grinding the main surfaces H of the piezoelectric material substrate 11 and the support substrate 13 at a grinding angle θ = 3.5° to 12.0°. Furthermore, in the grinding process, the length of the second inclined surface P2, which is exposed by the grinding of the piezoelectric material substrate 11 and thus the support substrate 13, when viewed from above, and the length in the direction from the center of the support substrate 13 towards the outer periphery, is 0.7 mm or more and 1.5 mm or less when viewed from above. As a result, a grinding surface P is formed, consisting of the first inclined surface P1 facing the piezoelectric material substrate 11 and the second inclined surface P2 facing the support substrate 13, and the first inclined surface P1 and the second inclined surface P2 are continuous.

[0051] Therefore, the above-mentioned grinding process can also be referred to as the following process: grinding is performed in a manner that forms an outer peripheral processing portion R consisting of a first inclined surface P1 that is inclined relative to the main surface H of the piezoelectric material substrate 11 and the piezoelectric material substrate 11 facing the first inclined surface P1 and the second inclined surface P2 that is facing the support substrate 13, and the first inclined surface P1 and the second inclined surface P2 are continuous.

[0052] If the aforementioned angle is 3.5° or more, an area sufficient for use as the bonding body 1 is obtained, which is preferable. Furthermore, if the angle is 12.0° or less, the possibility of corner formation and cracking or fissures occurring at the outer periphery during subsequent processes can be suppressed, which is also preferable. Additionally, if the aforementioned length is 0.7 mm or more, a smooth and continuous structure between the piezoelectric material substrate 11 and the support substrate 13 can be sufficiently ensured. Furthermore, if the aforementioned length is 1.5 mm or less, an area sufficient for use as the bonding body 1 is obtained, which is also preferable.

[0053] Figure 4 (D) in the diagram shows the state after the grinding process in step 107. That is, it shows the state after the grinding process in step 107. Figure 4 The state after the grinding surface P specified in (C) is ground and the outer peripheral processing part R is formed. This can be referred to as: after the edge grinding (outer peripheral grinding) of the piezoelectric material substrate 11 and the support substrate 13.

[0054] Alternatively, the assembly 1 can also be described as having a piezoelectric material substrate 11, a support substrate 13 bonded to the piezoelectric material substrate 11, and an outer peripheral processing section R obtained by processing the outer periphery of the piezoelectric material substrate 11 and the support substrate 13 in an inclined manner relative to the main surface H of the piezoelectric material substrate 11. The outer peripheral processing section R is composed of a first inclined surface P1 facing the piezoelectric material substrate 11 and a second inclined surface P2 facing the support substrate 13, and the first inclined surface P1 and the second inclined surface P2 are continuous.

[0055] In addition, as a configuration of the bonding body 1, it can also be described as follows: the first inclined surface P1 and the second inclined surface P2 of the outer peripheral processing part R are inclined at an angle of 3.5° or more and 12.0° or less relative to the main surface H of the piezoelectric material substrate 11.

[0056] Furthermore, as a component of the joint 1, it can also be described as having a length of 0.7 mm or more and 1.5 mm or less when viewed from above for the second inclined surface P2.

[0057] It should be noted that when a dielectric layer 12 exists between the piezoelectric material substrate 11 and the support substrate 13, the first inclined surface P1 and the second inclined surface P2 are discontinuous. As a configuration that also includes this situation, it can also be described as follows: the peripheral processing portion R includes a first inclined surface P1 facing the piezoelectric material substrate 11, and a second inclined surface located on a surface extending from the first inclined surface P1 toward the peripheral portion and facing the support substrate 13. That is, the first inclined surface P1 and the second inclined surface P2 are discontinuous, but they exist on the same surface, and the surface of the dielectric layer 12 exists between them. It should be noted that the surface of the dielectric layer 12 also exists on this surface.

[0058] Furthermore, in this case, the above-mentioned grinding process can also be referred to as: grinding in a manner to form an outer peripheral processing part R, which is composed of a first inclined surface P1 that is inclined relative to the main surface H of the piezoelectric material substrate 11 and faces the piezoelectric material substrate 11, and a second inclined surface P2 that is located on a surface extending from the first inclined surface P1 toward the outer peripheral portion and faces the support substrate 13, and includes the first inclined surface P1 and the second inclined surface P2.

[0059] Figure 5Figures (A) to (B) in this diagram compare the case where grinding was performed using the grinding process of this embodiment with the case where grinding was performed using a conventional method.

[0060] in, Figure 5 (A) shows the joint 1 obtained by grinding using the grinding process of this embodiment. In contrast, Figure 5 (B) shows the joint 1 obtained by grinding using a conventional grinding method.

[0061] Figure 5 In (A), by specifying the grinding surface P shown by the dashed line, a structure is obtained in which the first inclined surface P1 and the second inclined surface P2 forming the grinding surface P are continuous, and the piezoelectric layer 11a and the support substrate 13 are smoothly continuous.

[0062] In contrast, Figure 5 In (B) of the diagram, the polishing surface P is shown by the dashed line. In this case, two corners K are generated in the piezoelectric layer 11a and the support substrate 13.

[0063] Figure 5 In the bonding body 1 of (B), the unbonded portion X disappears; however, due to the presence of the corner K, cracks or fissures are easily generated on the outer periphery during subsequent processes such as grinding the piezoelectric material substrate 11. As a result, the yield rate decreases. On the other hand, Figure 5 In the joint 1 of (A), the polished surface P formed by grinding is inclined at a predetermined angle relative to the main surface H. Furthermore, at this time, the piezoelectric layer 11a and the support substrate 13 are designed to be smoothly continuous. Therefore, no corner K is formed, and cracks or fissures are less likely to occur at the outer periphery. It should be noted that in the joint 1 after edge grinding, it is not necessary for the entire edge to have the same angle; it is sufficient that the piezoelectric layer 11a is continuously inclined on the support substrate 13 side and the piezoelectric layer 11a side of the support substrate 13. Furthermore, if a dielectric layer 12 is provided between the piezoelectric layer 11a and the support substrate 13 side, the dielectric layer 12 is also continuously inclined in the same manner.

[0064] Example

[0065] (Example 1)

[0066] As the piezoelectric material substrate 11, a 42Y-cut black LiTaO3 (LT) substrate with a thickness of 0.25 mm and both sides polished to a mirror finish is prepared. In addition, as the support substrate 13, a high-resistivity (≥2kΩ·cm) Si substrate with a thickness of 0.23 mm is prepared.

[0067] Next, 0.5 μm SiO2 films are formed on the LT substrate and Si substrate as dielectric layer 12a and dielectric layer 12b, respectively (dielectric layer formation process). Their surfaces are then polished to approximately 0.1 μm using CMP (Chemical Mechanical Polishing) to achieve planarization.

[0068] The SiO2 film surfaces of the LT substrate and the Si substrate were activated by N2 plasma with a discharge output power of 100W (LT substrate side) and 65W (Si substrate side) respectively (activation process), and then bonded (bonding process). The vacuum time in the bonding process was 120 seconds.

[0069] To improve bonding strength, the bonded substrates are placed in an oven at 130°C and heated for 4 hours (heating process). The LT surface of the bonded substrates removed from the oven is then thinned to 2μm by grinding (grinding process).

[0070] Next, the GC#2000 polishing film is brought into contact with the outer periphery and polished for 120 seconds to remove any unbonded portions (polishing process). The angle of the head holding the polishing film is set to 79°. It should be noted that the film feed speed is 100 mm / min.

[0071] Finally, the LT surface was ground to a thickness of 1μm. However, no abnormalities such as peeling or damage to the LT substrate, gaps in the processed part, or cracks occurred.

[0072] Furthermore, the finished shape of the outer periphery was confirmed, and the result showed that the inclination was 8.1°, the processing width (from the end of the Si substrate to the end of the LT substrate) was 786μm (0.786mm), and there were no unbonded portions. That is, a polished surface P with an angle of 8.1° is formed relative to the surfaces of the LT substrate and the Si substrate.

[0073] (Example 2)

[0074] The width of the unbonded portion X is determined based on the chip's edge collapse. When using commercially available chips to fabricate the bond, the width of the unbonded portion X is 0.8 mm to 1.2 mm.

[0075] In Example 2, a bonding body 1 with a width of 1.2 mm for the unbonded portion X was used. The inclination angle of the grinding angle θ, which is the first inclined surface P1 and the second inclined surface P2, was set to 12°. The edge was ground, and as a result, the unbonded portion X was completely removed.

[0076] (Example 3)

[0077] In addition, in Embodiment 3, the tilt angle was set to 13°, and edge grinding was performed. In this case, the unbonded portion X was removed; however, the range that could be used as a device was reduced compared to the case where the tilt angle was 12°.

[0078] (Example 4)

[0079] In Example 4, a bonding body with an unbonded portion X having a width of 0.8 mm was used, and the aforementioned tilt angle was set to 3°, during edge grinding. While this process is possible, it requires precise control.

[0080] Figure 6 (A) to (D) in the figure are comparison diagrams of the grinding process and the lapping process before and after.

[0081] in, Figure 6 (A) is a diagram showing the state of the LT substrate and Si substrate from above before the grinding and polishing processes. Figure 6 (B) in the middle is Figure 6 The cross-sectional view of (A) in the diagram. Additionally, Figure 6 (C) is a diagram showing the state of the LT substrate and Si substrate after the grinding and polishing processes, viewed from above. Figure 6 (D) in the middle is Figure 6 The cross-sectional view of (C) in the diagram. That is, Figure 6 (B) and (D) in the text are from and Figure 4-5 Images showing the LT substrate and Si substrate viewed from the same direction.

[0082] Figure 6 (A) in the middle corresponds to Figure 4 In case (A), there is an unbonded portion (0.800 mm in length) where the LT substrate and Si substrate are separated. Additionally, as... Figure 6 As shown in (B), the outer periphery of the LT substrate has an angle of 23.8°.

[0083] Figure 6 (C) in the middle corresponds to Figure 4 Case (D) shows the state after grinding. It should be noted that... Figure 6 In section (C), the ground area is shown as the outer peripheral machined part. Additionally, as... Figure 6 As shown in (B), the outer periphery of the LT substrate at this time has an angle of 8.1° as described above.

[0084] The embodiments described above are for illustrative purposes only. However, the scope of the present invention is not limited to the scope described in the above embodiments. As can be seen from the claims, solutions obtained by making various modifications or improvements to the above embodiments are also included in the scope of the present invention.

[0085] Explanation of reference numerals in the attached figures

[0086] 1…Joint, 11…Piezoelectric material substrate, 11a…Piezoelectric layer, 12, 12a, 12b…Dielectric layers, 13…Support substrate, P…Grinding surface, P1…First inclined surface, P2…Second inclined surface, R…Outer peripheral processing part

Claims

1. A bonding body comprising: a piezoelectric material substrate; a support substrate bonded to the piezoelectric material substrate; and a peripheral processing portion formed by tilting the peripheral portions of the piezoelectric material substrate and the support substrate relative to the main surface of the piezoelectric material substrate. The peripheral machining section includes: The piezoelectric material substrate faces a first inclined surface, and the supporting substrate faces a second inclined surface located on a surface extending from the first inclined surface toward the outer periphery.

2. The joint according to claim 1, wherein, The first and second inclined surfaces of the peripheral processing portion are inclined at an angle of 3.5° or more and 12.0° or less relative to the main surface of the piezoelectric material substrate.

3. The joint according to claim 1 or 2, wherein, The length of the second inclined surface when viewed from above, and the length in the direction from the center of the support substrate toward the outer periphery, is 0.7 mm or more and 1.5 mm or less.

4. The joint according to claim 1, wherein, The supporting substrate is a substrate containing Si.

5. The joint according to claim 4, wherein, The piezoelectric material substrate and the support substrate are bonded together by means of a SiO2 layer.

6. A method for manufacturing a joint, comprising the following steps: The bonding process, in which the piezoelectric material substrate and the support substrate are bonded; and The grinding process involves grinding the outer periphery of the bonded piezoelectric material substrate and the support substrate. The grinding process is performed to form an outer peripheral machining portion, which includes: The first inclined surface is inclined relative to the main surface of the piezoelectric material substrate and faces the piezoelectric material substrate, and the second inclined surface is located on the surface extending from the first inclined surface toward the outer periphery and faces the support substrate.

7. The method for manufacturing the joint according to claim 6, wherein, Between the bonding process and the grinding process, there is also a grinding process in which the piezoelectric material substrate is ground into a thin film.

8. The method for manufacturing the joint according to claim 6 or 7, wherein, The process also includes an activation step, in which the surfaces of the piezoelectric material substrate and the support substrate, each having a surface primarily composed of SiO2, are activated using plasma. In the bonding process, the piezoelectric material substrate and the support substrate are bonded together by joining their surfaces together, thereby bonding the piezoelectric material substrate and the support substrate with the aid of a SiO2 layer.

9. The method for manufacturing the joint according to claim 8, wherein, It also includes a heating process in which the joined piezoelectric material substrate and the support substrate are heated.

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