Wafer bonding method and application thereof in preparation of composite substrate

Abstract

The invention relates to a wafer bonding method and application thereof in composite substrate preparation, and belongs to the technical field of composite substrate processing. The wafer bonding method comprises the steps that (1) ion implantation is carried out on a piezoelectric wafer to obtain a wafer implantation piece, and the wafer implantation piece sequentially comprises a thin film layer, an implantation layer and a residual layer; 2) separating the thin film layer of the wafer injection sheet from the supporting substrate, enabling a first bonding surface of the wafer injection sheet and a second bonding surface of the supporting substrate to be oppositely arranged and aligned, and simultaneously heating the wafer injection sheet and the supporting substrate for the first time, approaching each other and performing bonding treatment; the method comprises the steps of (1) bonding a first bonding surface and a second bonding surface, (2) applying a first pressure to the first bonding surface and the second bonding surface and keeping the first pressure and the second pressure for a period of time, (4) reducing the first pressure to a second pressure and carrying out second heating, and (5) carrying out third heating and keeping the temperature for a period of time to separate a film layer from a residual layer to obtain the composite substrate.The method can improve the quality and yield of the composite substrate, and is low in warping and small in hole number.

Description

Technical Field

[0001] The present application relates to a wafer bonding method and its application in the preparation of composite substrates, belonging to the processing technical field of composite substrates. Background Art

[0002] In recent years, high-performance radio frequency filters based on piezoelectric single crystal thin films have received extensive attention in the industry and have been more and more widely used. Correspondingly, the preparation technology of piezoelectric composite substrates is also developing in the direction of high efficiency, low cost, and high quality.

[0003] At present, the ion beam stripping technology is usually used to prepare composite substrates. First, the piezoelectric wafer is processed by ion implantation to form a thin film layer, a residual layer, and an implantation layer located between the thin film layer and the residual layer. Then, the surface of the thin film layer of the piezoelectric wafer is brought into contact with the polished surface of the support substrate to form a bonded body. Finally, the bonded body is heated for annealing treatment. During the annealing process, the ions in the implantation layer will form gas under the thermal effect, thereby generating bubbles in the implantation layer and connecting with each other, and finally the residual layer and the thin film layer are instantaneously separated to obtain a composite substrate.

[0004] The bonding process is an important method to realize heterogeneous integration technology. Among them, the direct bonding technology of the bonding process is to directly bond two wafers with sufficiently clean and smooth surfaces, and combine them by the intermolecular force between the two wafers or the interaction between the chemical bonds attached to the wafer surfaces. However, during the wafer bonding process, the two bonded wafers are likely to trap a part of the air in the bonding interface to form air gaps, thereby forming bonding holes that cannot be eliminated; secondly, for warped wafers, debonding will occur during bonding, directly resulting in wafer bonding failure; finally, annealing of the bonded body is required to prepare the composite substrate, the annealing time is very long and it is easy to break, resulting in a decrease in the yield and finished product rate of the composite substrate.

[0005] In the existing technical solutions, the method of directly bonding the wafers will cause bubble holes to form in the bonded wafers, debonding will occur for warped wafers, and at the same time, when annealing the bonded body, the yield of the composite substrate is low. Therefore, there is an urgent need for a wafer bonding method to avoid the bonding holes and debonding situations generated by the direct wafer bonding technology in the prior art, and the yield of the bonding process also needs to be improved, so as to improve the yield and finished product rate of the composite substrate. Summary of the Invention

[0006] In order to solve the above problems, a wafer bonding method and its application in the preparation of composite substrates are provided. The solution of the present application can effectively reduce the warpage of the bonded wafers and avoid the problems of excessive bonding holes and debonding, and the yield and finished product rate of the prepared composite substrates are significantly improved.

[0007] The present application provides a wafer bonding method, and the wafer bonding method includes the following steps: 1) Prepare a piezoelectric wafer and a support substrate; 2) Perform ion implantation on the piezoelectric wafer to obtain an implanted wafer, and the implanted wafer sequentially includes a thin film layer, an implanted layer, and a residual layer; 3) Separate the thin film layer of the implanted wafer from the support substrate, and make the first bonding surface of the implanted wafer and the second bonding surface of the support substrate face each other and be aligned. At the same time, perform a first heating on the implanted wafer and the support substrate, approach each other and perform a bonding process; 4) Apply a first pressure to the first bonding surface and the second bonding surface and maintain it for a period of time; 5) Reduce the first pressure to a second pressure and perform a second heating; 6) Perform a third heating and keep it warm for a period of time to separate the thin film layer from the residual layer to obtain a composite substrate.

[0008] Optionally, the first pressure ranges from 4000 to 6000 N; and / or, The second pressure ranges from 1500 to 2500 N.

[0009] Optionally, in step 3), the first heating is to 65 - 75 °C.

[0010] Optionally, in step 5), the second heating temperature is 240 - 280 °C and is maintained for 20 - 40 min.

[0011] Optionally, in step 6), the third heating temperature is 160 - 200 °C and is kept warm for 1.5 - 3 h.

[0012] Optionally, the energy of the ion implantation is 50 - 500 keV; and / or, The dose of the ion implantation is 3×10 15 ions / cm 2 ~5×10 18 ions / cm 2 ; and / or, The ion species used for the ion implantation is hydrogen ions, helium ions, or a mixed ion of hydrogen and helium.

[0013] Optionally, the thickness of the thin film layer is 100 - 2000 nm.

[0014] Optionally, the material of the support substrate is one or more of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide.

[0015] Optionally, the diameter sizes of the piezoelectric wafer and the support substrate are 4 - 12 inches, and the initial thickness is 100 - 1000 μm.

[0016] The present application provides an application of the above wafer bonding method in the preparation of a composite substrate.

[0017] The beneficial effects of the present application include but are not limited to: For the wafer bonding method of the present application and its application in the preparation of a composite substrate, through three heating processes and the application pressure process during bonding, the yield and the good rate of the composite substrate can be significantly improved, and the quality of the prepared composite substrate product is significantly improved.

[0018] For the first heating, the wafer injection sheet and the support substrate are heated once before bonding, and the temperature is kept unchanged during the bonding process. At the same time, the bonding pressure is applied to form a first bonded body, effectively reducing the thermal stress of the bonded body and the holes during the bonding process, improving the warping degree of the bonded body, and thus improving the bonding good rate.

[0019] For the second heating, the bonded body is heated to a second elevated temperature, and at the same time, the pressure value of the bonded body is reduced. At this temperature, bubbles can be formed in the injection layer of the piezoelectric wafer, greatly shortening the time required for annealing and peeling. The precise control of the pressure ensures that the warping generated during the further temperature increase process is further reduced while ensuring that the bubbles do not burst, thereby improving the production efficiency.

[0020] For the third heating, the bonded body after the second heating is heated to the target temperature and kept warm to separate the thin film layer from the remaining layer, and the injection layer is broken at a relatively low temperature, avoiding the problem of the bonded body cracking caused by high temperature and long annealing treatment time, and greatly improving the yield and the good rate of the composite substrate.

[0021] In addition, applying pressure during bonding can solve the debonding problem of warped wafers and effectively reduce the warping of the bonded wafers, and can also effectively avoid the bonding holes generated by the wafer direct bonding technology in the prior art. Description of the Drawings

[0022] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings: Figure 1 is a schematic process flow diagram related to the present application; Figure 2 is a schematic structural flow diagram related to the present application; Figure 3 is a warpage detection result diagram related to Embodiment 1 of the present application; Figure 4 is a warpage detection result diagram related to Embodiment 4 of the present application; Figure 5 This is the warpage detection result diagram related to Comparative Example 1 of the present application; Figure 6 This is the bonding hole morphology diagram related to Example 1 of the present application; Figure 7 This is the bonding hole morphology diagram related to Example 6 of the present application; Figure 8 This is the bonding hole morphology diagram related to Comparative Example 1 of the present application.

[0023] The list of drawings and reference signs is as follows: 100 - Piezoelectric wafer; 110 - Wafer injection sheet, 1101 - Thin film layer, 1102 - First injection layer, 1103 - Remaining layer; 120 - Support substrate; 130 - Bonded body, 1301 - Second remaining layer. Detailed description of the specific implementation mode

[0024] The present application will be described in detail below in conjunction with the embodiments. However, the present application is not limited to these embodiments. Unless otherwise specified, the raw materials and reagents in the embodiments of the present application are purchased through commercial channels.

[0025] The flow chart of the bonding process of the present application is as Figure 1 shown, and the specific bonding process schematic diagram is as Figure 2 shown. Prepare a piezoelectric wafer 100 and a support substrate 120; perform ion implantation on the piezoelectric wafer 100 to obtain a wafer injection sheet 110, and the wafer injection sheet sequentially includes a thin film layer 1101, an injection layer 1102, and a remaining layer 1103; Separate the thin film layer 1101 of the wafer injection sheet 110 from the support substrate 120, and make the first bonding surface of the wafer injection sheet 110 and the second bonding surface of the support substrate face each other and be aligned. At the same time, perform the first heating on the wafer injection sheet 110 and the support substrate 120, approach each other and perform the bonding process; apply the first pressure to the first bonding surface and the second bonding surface and maintain it for a period of time; reduce the first pressure to the second pressure, and perform the second heating on the bonded body 130 to form bubbles in the first remaining layer 1102 to form a second remaining layer 1301; perform the third heating on the bonded body 130 and keep it warm for a period of time to separate the thin film layer 1101 from the remaining layer 1103 to obtain a composite substrate.

[0026] The solution of the present application will be described below through specific embodiments.

[0027] Example 1 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-grade RCA cleaning on the two wafers to make their surfaces clean. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the support substrate; 2) Ion implant the piezoelectric wafer with an implant dose of 3×10 16 ions / cm 2 , an implant energy of 150 KeV, to form a wafer implant with a thin film layer, an implanted layer, and a residual layer; and perform semiconductor-level cleaning on the wafer implant to obtain a clean surface; 3) Separate the thin film layer of the wafer implant from the support substrate, and set the first bonding surface of the wafer implant and the second bonding surface of the support substrate opposite and aligned. At the same time, heat the wafer implant and the support substrate to 70°C at once, move them closer to each other and perform a bonding process; 4) Apply a pressure of 5000 N to the first bonding surface and the second bonding surface, and keep the temperature at 70°C and the pressure at 5000 N constant for 10 min; 5) Reduce the pressure of the bonded body to 2000 N, and perform secondary heating to 260°C and keep it warm for 30 min; 6) Perform three times of heating on the bonded body at a temperature of 180°C and a holding time of 2 h. The implanted layer breaks to separate the thin film layer from the residual layer, obtaining a piezoelectric composite substrate; 7) Fix the piezoelectric composite substrate on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing, and finally perform RCA cleaning to complete wafer bonding.

[0028] Example 2 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-level RCA cleaning on both wafers to make their surfaces clean. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the support substrate; 2) Ion implant the piezoelectric wafer with an implant dose of 3×10 15 ions / cm 2 , an implant energy of 50 KeV, to form a wafer implant with a thin film layer, an implanted layer, and a residual layer; and perform semiconductor-level cleaning on the wafer implant to obtain a clean surface; 3) Separate the thin film layer of the wafer implant from the support substrate, and set the first bonding surface of the wafer implant and the second bonding surface of the support substrate opposite and aligned. At the same time, heat the wafer implant and the support substrate to 65°C at once, move them closer to each other and perform a bonding process; 4) Apply a pressure of 4000 N to the first bonding surface and the second bonding surface, and keep the temperature at 65°C and the pressure at 4000 N constant for 10 min; 5) Reduce the pressure of the bonded body to 1500 N, and perform secondary heating to 240°C and keep it warm for 40 min; 6) Heat the bonded body three times at a temperature of 160 °C for 3 h of heat preservation time. The injection layer fractures to separate the thin film layer from the remaining mass layer, obtaining a piezoelectric composite substrate; 7) Fix the piezoelectric composite substrate on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform RCA cleaning to complete wafer bonding.

[0029] Example 3 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-grade RCA cleaning on both wafers to make their surfaces clean. The lithium tantalate wafer serves as the piezoelectric wafer, and the silicon carbide wafer serves as the support substrate; 2) Perform ion implantation on the piezoelectric wafer with an implantation dose of 5×10 18 ions / cm 2 , an implantation energy of 500 KeV, to form a wafer implantation sheet with a thin film layer, an injection layer, and a remaining mass layer; and perform semiconductor-grade cleaning on the wafer implantation sheet to obtain a clean surface; 3) Separate the thin film layer of the wafer implantation sheet from the support substrate, and arrange the first bonding surface of the wafer implantation sheet and the second bonding surface of the support substrate opposite to each other and aligned. At the same time, heat the wafer implantation sheet and the support substrate to 75 °C once, bring them closer to each other, and perform bonding treatment; 4) Apply a pressure of 6000 N to the first bonding surface and the second bonding surface, and maintain a constant pressure of 6000 N at a constant temperature of 75 °C for 10 min; 5) Reduce the pressure of the bonded body to 2500 N, and perform secondary heating to 280 °C and heat preservation for 20 min; 6) Heat the bonded body three times at a temperature of 200 °C for 1.5 h of heat preservation time. The injection layer fractures to separate the thin film layer from the remaining mass layer, obtaining a piezoelectric composite substrate; 7) Fix the piezoelectric composite substrate on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform RCA cleaning to complete wafer bonding.

[0030] Example 4 This example is basically the same as Example 1, except that in step 4), a pressure of 3000 N is applied to the first bonding surface and the second bonding surface, and in step 5), the pressure of the bonded body is reduced to 1000 N.

[0031] Example 5 This example is basically the same as Example 1, except that in step 3), the wafer implantation sheet and the support substrate are heated to 50 °C at the same time once.

[0032] Example 6 This embodiment is basically the same as Embodiment 1, except that in step 3), the wafer injection sheet and the support substrate are heated to 90 °C at one time.

[0033] Embodiment 7 This embodiment is basically the same as Embodiment 1, except that in step 5), the secondary heating is to 240 °C.

[0034] Embodiment 8 This embodiment is basically the same as Embodiment 1, except that in step 5), the secondary heating is to 280 °C.

[0035] Embodiment 9 This embodiment is basically the same as Embodiment 1, except that in step 6), the bonded body is heated three times at a temperature of 160 °C.

[0036] Embodiment 10 This embodiment is basically the same as Embodiment 1, except that in step 6), the bonded body is heated three times at a temperature of 200 °C.

[0037] Comparative Example 1 This embodiment is basically the same as Embodiment 1, except that the process of applying pressure to the first bonding surface and the second bonding surface is not included.

[0038] Comparative Example 2 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-grade RCA cleaning on the two wafers to make their surfaces clean. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the support substrate; 2) Perform ion implantation on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , an implantation energy of 150 KeV, to form a wafer injection sheet with a thin film layer, an implanted layer, and a residual layer; and perform semiconductor-grade cleaning on the wafer injection sheet to obtain a clean surface; 3) Separate the thin film layer of the wafer injection sheet from the support substrate, and arrange the first bonding surface of the wafer injection sheet and the second bonding surface of the support substrate opposite to each other and aligned. Apply a pressure of 5000 N to the first bonding surface and the second bonding surface, and at the same time heat the wafer injection sheet and the support substrate to 260 °C at one time, move them closer to each other and perform a bonding process; 4) Heat the bonded body for the second time at a temperature of 180 °C for a holding time of 2 h, and the implanted layer breaks to separate the thin film layer from the residual layer to obtain a piezoelectric composite substrate; 5) Fix the piezoelectric composite substrate on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform RCA cleaning to complete wafer bonding.

[0039] Comparative Example 3 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-grade RCA cleaning on both wafers to make their surfaces clean. The lithium tantalate wafer serves as the piezoelectric wafer, and the silicon carbide wafer serves as the support substrate; 2) Perform ion implantation on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , an implantation energy of 150 KeV, to form a wafer implantation sheet with a thin film layer, an implanted layer, and a residual layer; heat the wafer implantation sheet to 180°C once and keep it warm for 1 h, and then perform semiconductor-grade cleaning on the wafer implantation sheet to obtain a clean surface; 3) Separate the thin film layer of the wafer implantation sheet from the support substrate, and arrange the first bonding surface of the wafer implantation sheet and the second bonding surface of the support substrate opposite to each other and aligned, bring them closer to each other and perform bonding treatment. During the bonding treatment, heat the wafer implantation sheet and the support substrate to 260°C for the second time and keep it warm for 30 min to complete the bonding; 4) Heat the bonded body three times at a temperature of 180°C and keep it warm for 2 h. The implanted layer breaks to separate the thin film layer from the residual layer, obtaining a piezoelectric composite substrate; 5) Fix the piezoelectric composite substrate on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform RCA cleaning to complete wafer bonding.

[0040] Comparative Example 4 1) Provide a 4-inch lithium tantalate wafer and a silicon carbide wafer, and perform semiconductor-grade RCA cleaning on both wafers to make their surfaces clean. The lithium tantalate wafer serves as the piezoelectric wafer, and the silicon carbide wafer serves as the support substrate; 2) Perform ion implantation on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , an implantation energy of 150 KeV, to form a wafer implantation sheet with a thin film layer, an implanted layer, and a residual layer; perform semiconductor-grade cleaning on the wafer implantation sheet to obtain a clean surface; 3) Separate the thin film layer of the wafer implantation sheet from the support substrate, and arrange the first bonding surface of the wafer implantation sheet and the second bonding surface of the support substrate opposite to each other and aligned, bring them closer to each other and perform bonding treatment. During the bonding treatment, heat the wafer implantation sheet and the support substrate to 260°C for the first time and keep it warm for 30 min to complete the bonding; 4) Heat the bonded body twice at a temperature of 180°C and keep it warm for 2 h. The implanted layer breaks to separate the thin film layer from the residual layer, obtaining a piezoelectric composite substrate; 5) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing treatment is carried out, and finally RCA cleaning is carried out to complete wafer bonding.

[0041] Test Example 1 Performance detection was carried out on the composite substrate products prepared by using the methods of Examples 1 to 10 and Comparative Examples 1 to 4, and the bonding yield in the bonding process and the composite film yield of the final composite film product were counted.

[0042] Warpage (μm): The warpage of the wafer was detected and characterized by the commonly used semiconductor detection equipment Tropel. Warpage is the appearance manifestation of wafer stress. If the warpage is too large, the bonding effect is poor. For example, when the bonded body is separated in the annealing film layer and the remaining layer, the warpage caused by excessive stress will cause the bonded body to break.

[0043] Number of bonding holes: Observation was carried out using an infrared IR detection instrument. The entire area of the bonded wafer was directly observed, detection images were collected, and finally its number was counted and calculated.

[0044] Bonding yield (%): mainly reflects the bonding effect of the bonded wafer in the bonding process. The number of bonding holes of the bonded wafer from 0 to 1 is regarded as good. The bonding yield is calculated by the ratio of the wafers that meet the product requirements to the total wafers.

[0045] Composite film yield (%): mainly reflects the warpage and hole quality of the final composite film product. Warpage ≤ 15 μm and the number of bonding holes from 0 to 1 are regarded as good. The composite film yield is calculated by the ratio of the wafers that meet the product requirements to the total wafers.

[0046] The detection results are shown in Table 1 below.

[0047] Table 1 Detection results of the performance of the composite substrates in Examples and Comparative Examples

[0048] According to the results in Table 1, it can be seen that for Examples 1 to 3 in the present technical solution, the wafer warpage and the number of bonding holes are greatly improved, and the bonding yield and the composite film yield are greatly increased.

[0049] Comparing Example 1 with Example 4, it can be seen that when the pressure is too small, the wafer warpage increases, resulting in a decrease in the composite film yield and a deterioration in quality.

[0050] Comparing Example 1 with Example 5, it can be seen that when the primary heating temperature is too low, the wafer warpage increases, resulting in a decrease in the composite film yield and a deterioration in quality.

[0051] Comparing Example 1 with Example 6, it can be seen that when the primary heating temperature is too high, it will lead to an increase in wafer holes, resulting in a decrease in the bonding yield and the composite film yield and a deterioration in quality.

[0052] Comparing Comparative Example 1 with Example 7, it can be seen that when the secondary heating temperature is too low, it is difficult for the wafer to form bubbles in a short time, which will lead to a decrease in the yield of the composite film and a deterioration in quality.

[0053] Comparing Comparative Example 1 with Example 8, it can be seen that when the secondary heating temperature is too high, a large number of bubbles will be formed on the wafer in a short time, which will lead to failure of composite film peeling, a decrease in the yield of the composite film, and a deterioration in quality.

[0054] Comparing Comparative Example 1 with Example 9, it can be seen that when the tertiary heating temperature is too low, it is difficult for the composite film to be completely peeled off, which easily leads to peeling failure, a decrease in the yield of the composite film, and a deterioration in quality.

[0055] Comparing Comparative Example 1 with Example 10, it can be seen that when the tertiary heating temperature is too high, the peeling thermal stress of the composite film is relatively large, which easily leads to fragmentation of the composite film, resulting in a decrease in the yield of the composite film and a deterioration in quality.

[0056] Comparing Comparative Example 1 with Comparative Example 1, it can be seen that when there is no pressure application process, the warping of the wafer and the number of bonding holes increase significantly, and the yield of the obtained composite film is low and the quality is poor.

[0057] Comparing Comparative Example 1 with Comparative Example 2, it can be seen that in the secondary heating process it adopts, there is a situation where the stress during the bonding process cannot be completely released, resulting in an increase in warping and an increase in bonding holes, which will cause the composite film to be easily debonded, peeled off and fragmented, and the yield of the obtained composite film is low and the quality is poor.

[0058] Comparing Comparative Example 1 with Comparative Example 3, it can be seen that in the way it heats the wafer injection sheet, there is a phenomenon that the film spontaneously falls off during the cleaning process, resulting in an increase in bonding holes and a decrease in bonding yield. In addition, the secondary heating at 260 °C, heat preservation for 30 min and no pressure applied during the bonding process will lead to an increase in wafer warping, resulting in failure of composite film peeling and a decrease in the yield of the composite film.

[0059] Comparing Comparative Example 1 with Comparative Example 4, it can be seen that when the heating temperature of both the wafer injection sheet and the support substrate is too high during the bonding process, it is easy to cause incomplete release of thermal stress, and no pressure during the bonding process makes the warping of the composite film increase significantly and the bonding holes increase. During the secondary annealing process, debonding and peeling fragmentation occur, resulting in a relatively low yield of the composite film.

[0060] As described above, these are only the embodiments of the present application. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A wafer bonding method, characterized in that: The wafer bonding method comprises the following steps: 1) Prepare the piezoelectric wafer and supporting substrate; 2) performing ion implantation on the piezoelectric wafer to obtain an implanted wafer, wherein the implanted wafer includes a thin film layer, an implanted layer and a residual layer in sequence; 3) Separating the thin film layer of the wafer implant sheet from the supporting substrate, and making the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relatively arranged and aligned, and at the same time heating the wafer implant sheet and the supporting substrate for the first time, bringing them close to each other and performing bonding processing; 4) applying a first pressure to the first bonding surface and the second bonding surface and maintaining the pressure for a period of time; 5) reducing the first pressure to a second pressure and performing a second heating; 6) Perform a third heating and keep the temperature for a period of time to separate the film layer from the residual layer to obtain a composite substrate.

2. The wafer bonding method according to claim 1, characterized in that: The first pressure range is 4000~6000N; and / or, The second pressure range is 1500~2500N.

3. The wafer bonding method according to claim 1, characterized in that: In the step 3), the first heating is performed to 65-75°C.

4. The wafer bonding method according to claim 1, characterized in that: In the step 5), the second heating temperature is 240-280° C. and maintained for 20-40 minutes.

5. The wafer bonding method according to claim 1, characterized in that: In the step 6), the third heating temperature is 160-200° C. and is kept warm for 1.5-3 hours.

6. The wafer bonding method according to claim 1, characterized in that: The energy of the ion implantation is 50-500 KeV; and / or, The ion implantation dose is 3×10 15 ions / cm 2 ~5×10 18 ions / cm 2 and / or, The ion types used in the ion implantation are hydrogen ions, helium ions or mixed ions of hydrogen and helium.

7. The wafer bonding method according to claim 1, characterized in that: The thickness of the thin film layer is 100-2000 nm.

8. The wafer bonding method according to claim 1, characterized in that: The material of the support substrate is one or more of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide.

9. The wafer bonding method according to claim 1, characterized in that: The piezoelectric wafer and the supporting substrate have a diameter of 4 to 12 inches and an initial thickness of 100 to 1000 μm.

10. Application of the wafer bonding method according to any one of claims 1 to 9 in the preparation of a composite substrate.

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