Bonded wafer preparation method

Abstract

The invention relates to the technical field of semiconductors, in particular to a bonding wafer preparation method, which comprises the steps of providing a first wafer and a second wafer; putting the first wafer into a coating vacuum chamber, and depositing a diamond-like carbon film layer on the surface of the first wafer; protective gas and oxygen are introduced into an atomic gun, the atomic gun emits atomic beams towards the first wafer and the second wafer respectively, a first amorphous layer is formed on the surface of the side, close to the second wafer, of the first wafer, and a second amorphous layer is formed on the surface of the side, close to the first wafer, of the second wafer; and the first wafer and the second wafer are attached, so that the first amorphous layer and the second amorphous layer are bonded, and a bonded wafer is obtained. According to the embodiment of the invention, the bonding strength and the interface quality can be effectively improved, and the high-reliability bonded wafer with the diamond-like carbon film layer is obtained.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method for preparing a bonded wafer. Background Art

[0002] Diamond-like carbon (DLC) has the advantages of high hardness, excellent wear resistance and low friction coefficient, high thermal conductivity, low dielectric constant, wide band gap, good optical transmittance and biocompatibility. Applying DLC ​​film layer to bonded wafers can effectively improve the performance of power devices. For example, DLC is an excellent insulating material that can ensure that the surface acoustic wave (SAW) filter maintains good insulation during long-term operation, avoid electron breakdown, and improve the power durability of the surface acoustic wave filter. However, the use of traditional wafer bonding methods will result in insufficient bonding strength between DLC and the wafer, and there will be more interface defects, resulting in reduced performance and reliability of the device. Summary of the invention

[0003] The purpose of the present application is to provide a method for preparing a bonded wafer, which effectively improves the bonding strength and interface quality, and obtains a highly reliable bonded wafer with a diamond-like film layer.

[0004] The embodiment of the present application is implemented as follows: The present application provides a method for preparing a bonded wafer, comprising: Providing a first wafer and a second wafer; Placing a first wafer into a coating vacuum chamber, and depositing a diamond-like carbon film layer on a surface of the first wafer; Depositing a temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer; The second wafer is placed on the carrier of the bonding vacuum chamber, and the second wafer is sucked by a vacuum suction cup and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber so that the first wafer and the second wafer are arranged in parallel and spaced; protective gas and oxygen are introduced into the atomic gun, and the atomic gun emits atomic beams toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer; The first wafer is bonded to the second wafer so that the first amorphous layer is bonded to the second amorphous layer to obtain a bonded wafer.

[0005] As an optional implementation, the second wafer is placed on the carrier of the bonding vacuum chamber, the second wafer is adsorbed by a vacuum suction cup and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber; protective gas and oxygen are introduced into an atomic gun, and the atomic gun emits an atomic beam toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer, including: The volume ratio of the protective gas to oxygen is 4:1-6:1.

[0006] As an optional implementation, placing the first wafer into a coating vacuum chamber and depositing a diamond-like carbon film layer on the surface of the first wafer includes: introducing carbon source gas and hydrogen into the vacuum chamber; The vacuum chamber ionizes the carbon source gas through a radio frequency power supply to form carbon atoms, and the carbon atoms are deposited on the surface of the first wafer to form a diamond-like film layer.

[0007] As an optional embodiment, the vacuum chamber ionizes the carbon source gas through a radio frequency power supply to form carbon atoms, and the diamond-like film layer formed by the carbon atoms deposited on the surface of the first wafer includes: The thickness of the diamond-like carbon film layer is 1-1.5 μm.

[0008] As an optional implementation, the second wafer is placed on the carrier of the bonding vacuum chamber, the second wafer is adsorbed by a vacuum suction cup and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber; protective gas and oxygen are introduced into an atomic gun, and the atomic gun emits an atomic beam toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer, including: The first wafer includes an n-type single crystal silicon wafer; the second wafer includes a lithium niobate wafer.

[0009] As an optional implementation manner, after laminating the first amorphous layer and the second amorphous layer and applying a preset pressure for bonding to obtain a bonded wafer, the method includes: Slowly heat the bonded wafer from room temperature at a heating rate of 3-5°C / min until the temperature reaches 150°C; at the same time, introduce protective gas into the heating chamber; Continue heating the bonded wafer to 250°C at a heating rate of 7-8°C / min for 2-3 hours; Cool naturally to below 100°C, turn off the protective gas, and take out the bonded wafer.

[0010] As an optional implementation manner, depositing a temperature compensation layer on the surface of the first wafer with a diamond-like carbon film layer includes: performing a first polishing on the diamond-like carbon film layer; Depositing a silicon dioxide layer on the surface of the polished diamond-like carbon film layer by magnetron sputtering; The silicon dioxide layer is polished a second time.

[0011] As an optional implementation, after depositing the temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer, the method includes: The first wafer and the second wafer are immersed in deionized water, and taken out after the first ultrasonic cleaning; The first wafer and the second wafer are cleaned for the second time with ammonia water and then dried.

[0012] As an optional implementation manner, laminating the first wafer with the second wafer so that the first amorphous layer is bonded with the second amorphous layer to obtain a bonded wafer includes: The preset pressure for the first wafer to contact the second wafer is 300-800N.

[0013] The beneficial effects of the embodiments of the present application include: The bonding wafer preparation method provided in the embodiment of the present application includes: providing a first wafer and a second wafer; placing the first wafer into a coating vacuum chamber, and depositing a diamond-like film layer on the surface of the first wafer; depositing a temperature compensation layer on the surface of the first wafer with the diamond-like film layer; placing the second wafer into a carrier of the bonding vacuum chamber, using a vacuum suction cup to adsorb the second wafer and space it parallel to the carrier, and then placing the first wafer into the carrier of the bonding vacuum chamber so that the first wafer and the second wafer are arranged parallel to each other; introducing protective gas and oxygen into an atomic gun, and the atomic gun emits atomic beams toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer; the first wafer and the second wafer are bonded to each other so that the first amorphous layer and the second amorphous layer are bonded to obtain a bonded wafer. Compared with the prior art, the embodiments of the present application introduce a diamond-like carbon film layer and a temperature compensation layer and use atomic beam activation technology to form an amorphous layer on the wafer surface, thereby significantly enhancing the bonding strength between wafers, reducing interface defects, and improving the reliability and performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a flow chart of the bonding wafer preparation method according to an embodiment of the present application. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0018] Diamond-like carbon (DLC) has the advantages of high hardness, excellent wear resistance and low friction coefficient, high thermal conductivity, low dielectric constant, wide bandgap, good optical transmittance and biocompatibility. Applying DLC ​​film layer to bonded wafers can effectively improve the performance of power devices. For example, DLC is an excellent insulating material that can ensure that the surface acoustic wave filter maintains good insulation during long-term operation, avoid electron breakdown, and improve the power durability of the surface acoustic wave filter. However, the use of traditional wafer bonding methods will result in insufficient bonding strength between DLC and the wafer, and there will be more interface defects, resulting in reduced performance and reliability of the device.

[0019] In order to solve the above technical problems, an embodiment of the present application provides a method for preparing a bonded wafer.

[0020] Reference Figure 1 As shown, an embodiment of the present application provides a method for preparing a bonded wafer, comprising: S10, providing a first wafer and a second wafer; S20, placing the first wafer into a coating vacuum chamber, and depositing a diamond-like carbon film layer on the surface of the first wafer; S30, depositing a temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer; S40, placing the second wafer on the carrier of the bonding vacuum chamber, using a vacuum suction cup to absorb the second wafer and space it parallel to the carrier, and then placing the first wafer on the carrier of the bonding vacuum chamber so that the first wafer and the second wafer are arranged parallel to each other; introducing protective gas and oxygen into the atomic gun, and the atomic gun emits atomic beams toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer; S50 , laminating the first wafer and the second wafer so that the first amorphous layer and the second amorphous layer are bonded to obtain a bonded wafer.

[0021] It should be noted that the embodiment of the present application places the first wafer into a coating vacuum chamber and deposits a layer of diamond-like carbon film on its surface. The embodiment of the present application utilizes the high hardness, wear resistance, low friction coefficient and good thermal conductivity of diamond-like carbon, laying the foundation for subsequent improvement of the performance of power devices. Among them, the vacuum chamber is the chamber of a plasma enhanced chemical vapor deposition (PECVD) device.

[0022] In the embodiment of the present application, a temperature compensation layer is further deposited on the surface of the first wafer on which the diamond-like carbon film layer has been deposited, wherein the temperature compensation layer can be a silicon dioxide layer or other insulating layer.

[0023] It should be noted that silicon dioxide has a positive temperature coefficient, which can offset the negative temperature coefficient that the substrate material may have, thereby reducing the temperature sensitivity of the entire component and improving its stability at different temperatures.

[0024] In the embodiment of the present application, both the first wafer and the second wafer are placed in a bonding vacuum chamber, and the two wafers are arranged in parallel and spaced apart. Protective gas and oxygen are introduced into the atom gun, and then the atom gun is used to fire an atomic beam toward the first wafer and the second wafer respectively, so as to form an amorphous layer on the surface of the two wafers close to each other. This treatment method can enhance the surface activity of the wafer, improve the surface properties, and promote a stronger bond.

[0025] The embodiments of the present application have the following technical effects: The embodiment of the present application introduces a diamond-like carbon film layer and a temperature compensation layer and adopts atomic beam activation technology to form an amorphous layer on the surface of the wafer, thereby significantly enhancing the bonding strength between wafers, reducing interface defects, and improving the reliability and performance of the device.

[0026] The embodiments of the present application can improve device performance. The addition of a diamond-like film layer can increase the center frequency of the power device, improve the heat dissipation efficiency, and ensure good insulation during long-term operation, avoid the problem of electronic breakdown, and improve the power durability of the device. The silicon dioxide temperature compensation layer helps to compensate for the dimensional changes caused by temperature changes and ensure the stability and reliability of the device under different temperature conditions. The embodiments of the present application have good frequency selectivity, a quality factor (Q value) of up to 5000, extremely low insertion loss and excellent temperature stability, which is of great significance to the field of semiconductor manufacturing, especially the development of power devices and filters. Among them, the quality factor is defined as the ratio of the stored energy to the energy lost in each cycle, or equivalently, it can be understood as the ability of the resonator to maintain oscillation near its resonant frequency. A high Q value indicates that the system has low energy loss, good frequency selectivity, and a steep resonance curve, which is suitable for scenarios requiring precise frequency control.

[0027] As an optional implementation, placing the second wafer on the carrier of the bonding vacuum chamber, using a vacuum suction cup to absorb the second wafer and space it parallel to the carrier, and then placing the first wafer on the carrier of the bonding vacuum chamber so that the first wafer and the second wafer are arranged parallel to each other; introducing protective gas and oxygen into the atomic gun, and the atomic gun emits atomic beams toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer, including: The volume ratio of shielding gas to oxygen is 4:1-6:1.

[0028] It should be noted that the protective gas can be any one of argon, nitrogen and helium.

[0029] It should be noted that, since argon is inert, it will not chemically react with the target or other materials, thereby avoiding the generation of unnecessary chemical by-products and reducing the introduction of impurities.

[0030] It should be noted that oxygen is introduced into the embodiment of the present application, and oxygen can change its chemical properties by interacting with the wafer surface, increasing the active sites on the surface. In addition, oxygen can react with organic pollutants on the surface, converting them into volatile compounds that are easy to remove, thereby achieving surface cleaning. Among them, the surface roughness of the wafer is reduced by cleaning, the generation of voids is reduced, and the bonding strength is indirectly enhanced.

[0031] It should be noted that oxygen molecules are decomposed into oxygen atoms under the action of high-energy particle beams. Oxygen atoms can combine with atoms on the surface of the wafer to generate new chemical bonds or dangling bonds, thereby increasing the chemical activity of the surface and facilitating the subsequent bonding process.

[0032] Those skilled in the art can select the specific type of protective gas and the ratio of protective gas to oxygen as required.

[0033] Exemplarily, the ratio of argon to oxygen is 5:1.

[0034] As an optional implementation, placing the first wafer into a coating vacuum chamber and depositing a diamond-like carbon film layer on the surface of the first wafer includes: introducing carbon source gas and hydrogen gas into the vacuum chamber; The vacuum chamber ionizes the carbon source gas through a radio frequency power supply to form carbon atoms, and the carbon atoms are deposited on the surface of the first wafer to form a diamond-like film layer.

[0035] It should be noted that carbon source gas and hydrogen are introduced into the vacuum chamber. Among them, the carbon source gas is the main raw material for forming the diamond-like film layer, while hydrogen can adjust the performance of the film and help remove unnecessary carbon impurities, thereby optimizing the film quality. The vacuum chamber is equipped with a radio frequency power supply for ionizing the introduced carbon source gas. The radio frequency power supply generates a high-frequency electromagnetic field to ionize the carbon source gas molecules to generate a plasma state. In this process, carbon atoms are activated and separated from the gas molecules. The activated carbon atoms move freely in the vacuum chamber and are eventually deposited on the surface of the first wafer. As the process proceeds, the carbon atoms gradually accumulate and form a uniform and dense diamond-like film layer.

[0036] The carbon source gas may be methane, acetylene or other gases.

[0037] As an optional embodiment, the vacuum chamber ionizes the carbon source gas by a radio frequency power supply to form carbon atoms, and the diamond-like film layer formed by the carbon atoms deposited on the surface of the first wafer includes: The thickness of the diamond-like carbon film is 1-1.5 μm.

[0038] Specifically, the carbon source gas and hydrogen are introduced into the PECVD reaction chamber through a precise gas flow control system to ensure that the gas flow is stable and the ratio is accurate. For example, for a mixed gas of methane and hydrogen, the flow rate of methane can be controlled within 30-60sccm, and the flow rate of hydrogen can be within the range of 20-100sccm. The carbon source gas molecules undergo decomposition and recombination reactions, and carbon atoms are deposited on the surface of the wafer and gradually form a diamond-like film. During the deposition process, the temperature of the reaction chamber is maintained at 100-300°C. The deposition time is adjusted according to the thickness of the required diamond-like film layer, generally within the range of 20-60 minutes.

[0039] As an optional implementation, placing the second wafer on the carrier of the bonding vacuum chamber, using a vacuum suction cup to absorb the second wafer and space it parallel to the carrier, and then placing the first wafer on the carrier of the bonding vacuum chamber so that the first wafer and the second wafer are arranged parallel to each other; introducing argon gas and oxygen into an atomic gun, and the atomic gun emits an atomic beam toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer, including: The first wafer includes an n-type single crystal silicon wafer; the second wafer includes a lithium niobate wafer.

[0040] It should be noted that two atom guns are used to irradiate the n-type single crystal silicon wafer and the lithium niobate wafer respectively. The high-energy particle beams generated by the atom guns hit the surface of the above wafers, so that the surface atoms gain enough energy to form dangling bonds, which provide active sites for subsequent chemical bonding.

[0041] It should be noted that the first wafer can also be made of any material such as silicon carbide, sapphire and quartz.

[0042] At the same time as the atomic gun irradiation, the embodiment of the present application also includes a sputtering process of the silicon target material, that is, during the atomic gun irradiation process, the silicon target material is bombarded by high-energy particles, causing silicon atoms to be sputtered out and deposited on the surface of the wafer. For the first wafer side, since the silicon material is sputtered, an amorphous layer of silicon is formed on its surface; and for the second wafer side, an amorphous layer of lithium niobate is formed. When the two amorphous layers are in contact and combined under a certain pressure, the atoms in the amorphous layer will rearrange and form new chemical bonds, thereby achieving a stable connection between the wafers. Not only does it improve the bonding strength, it also helps to reduce interface defects and improve the performance and reliability of the final device.

[0043] As an optional implementation, after laminating the first amorphous layer and the second amorphous layer and applying a preset pressure for bonding to obtain a bonded wafer, the method includes: Slowly heat the bonded wafer from room temperature at a heating rate of 3-5°C / min until the temperature reaches 150°C; at the same time, introduce protective gas into the heating chamber; Continue heating the bonded wafer to 250°C at a heating rate of 7-8°C / min for 2-3 hours; Cool naturally to below 100°C, turn off the protective gas, and take out the bonded wafer.

[0044] It should be noted that the addition of annealing in the embodiment of the present application can repair the bonded wafer lattice and improve the bonding strength. During the annealing process, the material is heated at a temperature below its melting point and maintained for a period of time, and the atoms obtain enough energy to diffuse. At the bonding interface, the diffusion of atoms allows the atoms on both sides of the interface to penetrate each other, forming a wider range of interatomic bonds, thereby increasing the bonding area and making the bonding stronger. Cleaning can remove particles on the surface of the wafer and reduce the formation of defects. Cleaning provides a clean and highly active surface for bonding by removing pollutants on the surface of the material, activating the surface, etc., thereby effectively improving the bonding strength.

[0045] As an optional implementation, depositing a temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer includes: Performing a first polishing on the diamond-like carbon film layer; Depositing a silicon dioxide layer on the surface of the polished diamond-like carbon film layer by magnetron sputtering; The silicon dioxide layer is polished a second time.

[0046] As an optional implementation, after depositing a temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer, the method includes: The first wafer and the second wafer are immersed in deionized water, and taken out after the first ultrasonic cleaning; The first wafer and the second wafer are cleaned for the second time with ammonia water and then dried.

[0047] As an optional implementation manner, laminating the first wafer with the second wafer so that the first amorphous layer is bonded with the second amorphous layer to obtain a bonded wafer includes: The preset pressure for the first wafer to contact the second wafer is 300-800N.

[0048] Furthermore, the present application provides a specific implementation method: The diamond-like carbon film layer is polished for the first time, wherein the roughness is ≤0.5 nm and the flatness is ≤0.6 μm.

[0049] A silicon dioxide layer with a thickness of 300-800 nm is deposited on the surface of the polished diamond-like film layer by magnetron sputtering, wherein the RF power is 20-100 W, the chamber pressure is 0.5-2 Pa, the argon flow rate is 20-80 sccm, the oxygen flow rate is 0-1 sccm, and the deposition time is 5-30 min.

[0050] Polish the surface of the silicon dioxide layer on the diamond-like carbon film layer; prepare a polishing liquid containing silicon dioxide abrasive. The composition and concentration of the polishing liquid will be adjusted according to the specific process requirements. For example, the silicon dioxide: water ratio of the polishing liquid is 1:5. The polishing time is 30-90s, the polishing pressure is 3-5psi, the polishing head speed is 60-80rpm, and the roughness after polishing is ≤0.6nm and the flatness is ≤0.8μm.

[0051] The surfaces of the first wafer and the second wafer were ultrasonically rinsed with deionized water for 10 minutes to remove large particles on the surface, and then single-wafer scrubbing was performed with ammonia water for 10 minutes to remove organic matter, metal ions and other impurities on the wafer surface, and then nitrogen drying was performed.

[0052] The first wafer and the second wafer are placed in a vacuum chamber with a vacuum degree of 1×10 -5 -1×10 -6 Pa, a 5:1 ratio of argon and oxygen mixed gas is introduced into the atomic gun, wherein the gas flow rate is 30-33sccm, the introduction time is 300s, the current is 95-105mA, and the voltage is 1.3-1.5Kv.

[0053] It should be noted that those skilled in the art may adjust the above parameter settings as needed, and no special limitation is imposed on this.

[0054] In addition, the blade insertion method can be used to test the above-mentioned bonded wafer. The bonding strength of the bonded wafer in the above-mentioned embodiment of the present application is 1.5 J / m 2 .

[0055] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a bonded wafer, characterized in that: include: Providing a first wafer and a second wafer; placing a first wafer into a coating vacuum chamber, and depositing a diamond-like carbon film layer on a surface of the first wafer; Depositing a temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer; The second wafer is placed on the carrier of the bonding vacuum chamber, and the second wafer is sucked by a vacuum suction cup and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber; protective gas and oxygen are introduced into the atomic gun, and the atomic gun emits atomic beams toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on the surface of the first wafer on the side close to the second wafer, and a second amorphous layer is formed on the surface of the second wafer on the side close to the first wafer; The first wafer is bonded to the second wafer so that the first amorphous layer is bonded to the second amorphous layer to obtain a bonded wafer.

2. The method for preparing a bonded wafer according to claim 1, characterized in that: The second wafer is placed on the carrier of the bonding vacuum chamber, the second wafer is sucked by a vacuum chuck and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber; protective gas and oxygen are introduced into an atom gun, and the atom gun emits an atomic beam toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on a surface of the first wafer close to the second wafer, and a second amorphous layer is formed on a surface of the second wafer close to the first wafer, including: The volume ratio of the protective gas to oxygen is 4:1-6:

1.

3. The method for preparing a bonded wafer according to claim 2, characterized in that: Placing the first wafer into a coating vacuum chamber and depositing a diamond-like carbon film layer on the surface of the first wafer comprises: introducing carbon source gas and hydrogen into the vacuum chamber; The vacuum chamber ionizes the carbon source gas through a radio frequency power supply to form carbon atoms, and the carbon atoms are deposited on the surface of the first wafer to form a diamond-like film layer.

4. The method for preparing a bonded wafer according to claim 3, characterized in that: The vacuum chamber ionizes the carbon source gas through a radio frequency power supply to form carbon atoms, and the diamond-like film layer formed by the carbon atoms depositing on the surface of the first wafer includes: The thickness of the diamond-like carbon film layer is 1-1.5 μm.

5. The method for preparing a bonded wafer according to any one of claims 1 to 4, characterized in that: The second wafer is placed on the carrier of the bonding vacuum chamber, the second wafer is sucked by a vacuum chuck and spaced parallel to the carrier, and then the first wafer is placed on the carrier of the bonding vacuum chamber; protective gas and oxygen are introduced into an atom gun, and the atom gun emits an atomic beam toward the first wafer and the second wafer respectively, so that a first amorphous layer is formed on a surface of the first wafer close to the second wafer, and a second amorphous layer is formed on a surface of the second wafer close to the first wafer, including: The first wafer includes an n-type single crystal silicon wafer; the second wafer includes a lithium niobate wafer.

6. The method for preparing a bonded wafer according to any one of claims 1 to 4, characterized in that: After laminating the first amorphous layer and the second amorphous layer and applying a preset pressure for bonding to obtain a bonded wafer, the method comprises: Slowly heat the bonded wafer from room temperature at a heating rate of 3-5°C / min until the temperature reaches 150°C; at the same time, introduce protective gas into the heating chamber; Continue heating the bonded wafer to 250°C at a heating rate of 7-8°C / min for 2-3 hours; Cool naturally to below 100°C, turn off the protective gas, and take out the bonded wafer.

7. The method for preparing a bonded wafer according to any one of claims 1 to 4, characterized in that: The step of depositing a temperature compensation layer on the surface of the first wafer having a diamond-like carbon film layer comprises: performing a first polishing on the diamond-like carbon film layer; Depositing a silicon dioxide layer on the surface of the polished diamond-like carbon film layer by magnetron sputtering; The silicon dioxide layer is polished a second time.

8. The method for preparing a bonded wafer according to any one of claims 1 to 4, characterized in that: After depositing the temperature compensation layer on the surface of the first wafer with the diamond-like carbon film layer, the method comprises: The first wafer and the second wafer are immersed in deionized water, and taken out after the first ultrasonic cleaning; The first wafer and the second wafer are cleaned for the second time with ammonia water and then dried.

9. The method for preparing a bonded wafer according to any one of claims 1 to 4, characterized in that: The first wafer is bonded to the second wafer so that the first amorphous layer is bonded to the second amorphous layer to obtain a bonded wafer, comprising: The preset pressure for the first wafer to contact the second wafer is 300-800N.

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