A wafer bonding method and its application in composite substrate preparation

Abstract

The present application relates to a wafer bonding method and its application in the preparation of composite substrates, and belongs to the field of composite substrate processing technology. The wafer bonding method of the present application includes: 1) ion implantation of a piezoelectric wafer to obtain a wafer implantation sheet, which includes a thin film layer, an implantation layer, and a residual layer in sequence; 2) separating the thin film layer of the wafer implantation sheet from the supporting substrate, and making the first bonding surface of the wafer implantation sheet and the second bonding surface of the supporting substrate relatively arranged and aligned, while heating the wafer implantation sheet and the supporting substrate for the first time, bringing them close to each other and performing a bonding process; 3) applying a first pressure to the first bonding surface and the second bonding surface, and maintaining it for a period of time; 4) reducing the first pressure to a second pressure, and performing a second heating; 5) performing a third heating, and keeping it warm for a period of time to separate the thin film layer from the residual layer, to obtain a composite substrate. This method can improve the quality and yield of the composite substrate, with low warping and a small number of holes.

Description

Technical Field

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

[0002] In recent years, high-performance radio frequency filters based on piezoelectric single crystal thin films have attracted widespread attention and are finding increasingly widespread application. Consequently, the fabrication technology for piezoelectric composite substrates is also developing towards high efficiency, low cost, and high quality.

[0003] Currently, ion beam stripping (IBSL) technology is commonly used to fabricate composite substrates. First, a piezoelectric wafer is treated with ion implantation to form a thin film layer, a residual layer, and an implanted layer between the thin film and residual layers. The surface of the thin film layer on the piezoelectric wafer is then brought into contact with the polished surface of the supporting substrate to form a bond. Finally, the bond is heated for annealing. During the annealing process, the ions in the implanted layer form gases under the thermal effect, creating bubbles between the implanted layers. These bubbles connect to each other, ultimately separating the residual layer from the thin film layer instantaneously, resulting in a composite substrate.

[0004] The bonding process is an important method for achieving heterogeneous integration technology. Direct bonding technology involves directly attaching two wafers with sufficiently clean and smooth surfaces, utilizing intermolecular forces between the two wafers or the interaction between chemical bonds attached to the wafer surfaces. However, during wafer bonding, the two bonded wafers can easily trap some air at the bonding interface, forming air gaps and thus forming bond holes that cannot be eliminated. Furthermore, warped wafers can debond during bonding, leading to wafer bonding failure. Finally, preparing a composite substrate requires annealing the bonded body, which takes a long time and is prone to breakage, resulting in a decrease in the yield and finished product rate of the composite substrate.

[0005] The existing technology, which involves direct wafer bonding, can cause air bubbles and voids in the bonded wafers, and can cause debonding in warped wafers. Furthermore, when the bonded body is annealed, the yield rate of the composite substrate is low. Therefore, a wafer bonding method is urgently needed to avoid the bond voids and debonding caused by the existing direct wafer bonding technology. Furthermore, the yield rate of the bonding process needs to be improved, thereby increasing the yield rate 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 warping of the bonded wafers and avoid the problems of excessive bonding holes and debonding. The yield and finished product rate of the prepared composite substrates are significantly improved.

[0007] The present application provides a wafer bonding method, which includes the following steps:

[0008] 1) Prepare the piezoelectric wafer and supporting substrate;

[0009] 2) performing ion implantation on the piezoelectric wafer to obtain an implanted wafer, which includes a thin film layer, an implanted layer, and a residual layer in sequence;

[0010] 3) Separating the thin film layer of the wafer implant sheet from the supporting substrate, and positioning the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other and aligning them, while heating the wafer implant sheet and the supporting substrate for the first time, bringing them closer together, and performing a bonding process;

[0011] 4) applying a first pressure to the first bonding surface and the second bonding surface and maintaining the pressure for a period of time;

[0012] 5) reducing the first pressure to a second pressure and performing a second heating;

[0013] 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.

[0014] Optionally, the first pressure range is 4000~6000N; and / or,

[0015] The second pressure range is 1500~2500N.

[0016] Optionally, in step 3), the first heating is to 65-75° C.

[0017] Optionally, in step 5), the second heating temperature is 240-280° C. and maintained for 20-40 minutes.

[0018] Optionally, the third heating temperature in step 6) is 160-200° C. and is kept warm for 1.5-3 hours.

[0019] Optionally, the energy of the ion implantation is 50-500 KeV; and / or,

[0020] The ion implantation dose is 3×10 15 ions / cm 2 ~5×10 18 ions / cm 2 and / or,

[0021] The ion types used in the ion implantation are hydrogen ions, helium ions or mixed ions of hydrogen and helium.

[0022] Optionally, the thickness of the thin film layer is 100-2000 nm.

[0023] Optionally, the material of the support substrate is one or more of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide.

[0024] Optionally, the piezoelectric wafer and the supporting substrate have a diameter of 4 to 12 inches and an initial thickness of 100 to 1000 μm.

[0025] The present application provides the application of the above-mentioned wafer bonding method in the preparation of a composite substrate.

[0026] The beneficial effects of this application include but are not limited to:

[0027] The wafer bonding method of the present application and its application in the preparation of composite substrates can greatly improve the production rate and yield of composite substrates through three heating and bonding pressure application processes, and significantly improve the quality of the prepared composite substrate products.

[0028] For single heating, the wafer implant and supporting substrate are heated once before bonding, and their temperature is kept constant during the bonding process. At the same time, bonding pressure is applied to form a first bonding body, which effectively reduces the thermal stress of the bonding body and the holes in the bonding process, improves the warping degree of the bonding body, and thus improves the bonding yield.

[0029] For secondary heating, the bonded body is heated at a higher temperature for a second time while 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 pressure ensures that the warping generated during the temperature increase process is further reduced while ensuring that the bubbles do not burst, thereby improving production efficiency.

[0030] For the triple heating, the twice-heated bonded body is heated three times to the target temperature and kept warm to separate the thin film layer from the residual layer, and the injection layer is broken at a relatively low temperature, avoiding the occurrence of bond breakage caused by high temperature and long annealing time, thereby greatly improving the finished product rate and yield of the composite substrate.

[0031] In addition, applying pressure during bonding can solve the debonding problem of the warped wafer and effectively reduce the warping of the bonded wafer, and can also effectively avoid the bonding holes generated by the wafer direct bonding technology in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0033] Figure 1 A schematic diagram of the process flow involved in this application;

[0034] Figure 2 This is a schematic diagram of the structural flow involved in this application;

[0035] Figure 3 This is a diagram of the warpage detection results involved in Example 1 of the present application;

[0036] Figure 4 This is a diagram of the warpage detection results involved in Example 4 of the present application;

[0037] Figure 5 This is a diagram of the warpage test results involved in Comparative Example 1 of the present application;

[0038] Figure 6 This is a topography image of the bonding hole involved in Example 1 of the present application;

[0039] Figure 7 This is a topography image of the bonding hole involved in Example 6 of the present application;

[0040] Figure 8 This is a morphology diagram of the bonding holes involved in Comparative Example 1 of this application.

[0041] The following are the list of drawings and reference numerals:

[0042] 100-piezoelectric wafer;

[0043] 110-wafer implantation sheet, 1101-thin film layer, 1102-first implantation layer, 1103-residual material layer;

[0044] 120-support substrate;

[0045] 130-bonding body, 1301-second residual layer. DETAILED DESCRIPTION

[0046] The present application is described in detail below with reference to examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels.

[0047] The flow chart of the bonding process of this application is as follows Figure 1 The specific bonding process diagram is shown in Figure 2 As shown, a piezoelectric wafer 100 and a supporting substrate 120 are prepared; the piezoelectric wafer 100 is ion-implanted to obtain a wafer-implanted sheet 110, which includes a thin film layer 1101, an implanted layer 1102, and a residual layer 1103 in sequence;

[0048] The thin film layer 1101 of the wafer injection piece 110 is separated from the supporting substrate 120, and the first bonding surface of the wafer injection piece 110 and the second bonding surface of the supporting substrate are arranged relative to each other and aligned. At the same time, the wafer injection piece 110 and the supporting substrate 120 are heated for the first time, brought close to each other and bonded; a first pressure is applied to the first bonding surface and the second bonding surface and maintained for a period of time; the first pressure is reduced to a second pressure, and the bonding body 130 is heated for a second time to form bubbles in the first residual layer 1102 and form a second residual layer 1301; the bonding body 130 is heated for a third time and kept warm for a period of time to separate the thin film layer 1101 from the residual layer 1103 to obtain a composite substrate.

[0049] The present application is described below through specific embodiments.

[0050] Example 1

[0051] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0052] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , the implantation energy is 150 KeV, forming a wafer implantation sheet having a thin film layer, an implantation layer and a residual layer; and performing semiconductor-grade cleaning on the wafer implantation sheet to obtain a clean surface;

[0053] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and position the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other and align them. Heat the wafer implant sheet and the supporting substrate to 70°C at the same time, bring them close to each other, and perform bonding.

[0054] 4) Apply a pressure of 5000N to the first and second bonding surfaces, maintain a constant temperature of 70°C and a constant pressure of 5000N for 10 minutes;

[0055] 5) Reduce the pressure of the bonded body to 2000N and heat it again to 260℃ and keep it warm for 30min;

[0056] 6) The bonded body is heated three times at 180°C for 2 hours, and the injection layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0057] 7) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0058] Example 2

[0059] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0060] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 3×10 15 ions / cm 2 , the implantation energy is 50 KeV, forming a wafer implantation sheet having a thin film layer, an implantation layer and a residual layer; and performing semiconductor-level cleaning on the wafer implantation sheet to obtain a clean surface;

[0061] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and position the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other and align them. Heat the wafer implant sheet and the supporting substrate to 65°C at the same time, bring them close to each other, and perform bonding.

[0062] 4) Apply a pressure of 4000N to the first and second bonding surfaces, maintain a constant temperature of 65°C and a constant pressure of 4000N for 10 minutes;

[0063] 5) Reduce the pressure of the bonded body to 1500N and perform secondary heating to 240℃ and keep warm for 40min;

[0064] 6) The bonded body is heated three times at 160°C for 3 hours, and the injected layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0065] 7) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0066] Example 3

[0067] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0068] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 5×10 18 ions / cm 2 , the implantation energy is 500 KeV, forming a wafer implantation sheet having a thin film layer, an implantation layer and a residual layer; and performing semiconductor-level cleaning on the wafer implantation sheet to obtain a clean surface;

[0069] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and position the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other and align them. Heat the wafer implant sheet and the supporting substrate to 75°C at the same time, bring them close to each other, and perform bonding.

[0070] 4) Apply a pressure of 6000N to the first and second bonding surfaces, maintain a constant temperature of 75°C and a constant pressure of 6000N for 10 minutes;

[0071] 5) Reduce the pressure of the bonded body to 2500N and perform secondary heating to 280℃ and keep warm for 20min;

[0072] 6) The bonded body is heated three times at 200°C for 1.5 hours, and the injected layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0073] 7) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0074] Example 4

[0075] This embodiment is substantially the same as embodiment 1, except that, in step 4), a pressure of 3000N is applied to the first bonding surface and the second bonding surface, and in step 5), the pressure of the bonding body is reduced to 1000N.

[0076] Example 5

[0077] This embodiment is basically the same as embodiment 1, except that in step 3), the wafer implantation sheet and the supporting substrate are heated to 50° C. at the same time.

[0078] Example 6

[0079] This embodiment is basically the same as embodiment 1, except that in step 3), the wafer implantation sheet and the supporting substrate are heated to 90° C. at the same time.

[0080] Example 7

[0081] This embodiment is basically the same as embodiment 1, except that, in step 5), secondary heating to 240° C. is performed.

[0082] Example 8

[0083] This embodiment is basically the same as embodiment 1, except that, in step 5), secondary heating to 280° C. is performed.

[0084] Example 9

[0085] 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.

[0086] Example 10

[0087] 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.

[0088] Comparative Example 1

[0089] This embodiment is substantially the same as the first embodiment, except that the process of applying pressure to the first bonding surface and the second bonding surface is not included.

[0090] Comparative Example 2

[0091] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0092] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , the implantation energy is 150 KeV, forming a wafer implantation sheet having a thin film layer, an implantation layer and a residual layer; and performing semiconductor-grade cleaning on the wafer implantation sheet to obtain a clean surface;

[0093] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and align the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other. Apply a pressure of 5000N to the first bonding surface and the second bonding surface. Simultaneously, heat the wafer implant sheet and the supporting substrate to 260°C, bring them close together, and perform a bonding process.

[0094] 4) The bonded body is heated again at 180°C for 2 hours, and the injection layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0095] 5) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0096] Comparative Example 3

[0097] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0098] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 3×1016 ions / cm 2 The implantation energy is 150 KeV, forming an implanted wafer having a thin film layer, an implanted layer, and a residual layer; the implanted wafer is heated to 180°C for one hour, and then the implanted wafer is cleaned at the semiconductor level to obtain a clean surface;

[0099] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and align and position the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other. Bond them close to each other and heat them to 260°C for 30 minutes to complete the bonding process.

[0100] 4) The bonded body is heated three times at 180°C for 2 hours, and the injection layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0101] 5) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0102] Comparative Example 4

[0103] 1) Provide 4-inch lithium tantalate wafers and silicon carbide wafers, and perform semiconductor-grade RCA cleaning on both wafers to ensure a clean surface. The lithium tantalate wafer is used as the piezoelectric wafer, and the silicon carbide wafer is used as the supporting substrate.

[0104] 2) Ion implantation is performed on the piezoelectric wafer with an implantation dose of 3×10 16 ions / cm 2 , the implantation energy is 150 KeV, forming a wafer implantation sheet having a thin film layer, an implantation layer and a residual layer; the wafer implantation sheet is cleaned at the semiconductor level to obtain a clean surface;

[0105] 3) Separate the thin film layer of the wafer implant sheet from the supporting substrate, and align and position the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other. Bond them close to each other and heat the wafer implant sheet and the supporting substrate to 260°C at the same time during the bonding process. Keep the temperature for 30 minutes to complete the bonding.

[0106] 4) The bonded body is heated again at 180°C for 2 hours, and the injection layer is broken to separate the thin film layer from the residual layer, thereby obtaining a piezoelectric composite substrate;

[0107] 5) The piezoelectric composite substrate is fixed on the porous ceramic chuck of the polishing equipment, then chemical mechanical polishing is performed, and finally RCA cleaning is performed to complete wafer bonding.

[0108] Test Example 1

[0109] Performance tests were performed on the composite substrate products prepared 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 statistically analyzed.

[0110] Warpage (μm): The warpage of the wafer is detected and characterized using Tropel, a commonly used semiconductor testing equipment. Warpage is the appearance of wafer stress. If the warpage is too large, the bonding effect will be poor. For example, when the bond body is separated from the annealed film layer and the residual layer, the warpage caused by excessive stress will cause the bond body to break.

[0111] Number of bonding holes: Use infrared IR detection equipment to observe and directly observe the entire area of ​​the bonded wafer, collect detection images, and finally count and calculate their number.

[0112] The bonding yield (%) mainly reflects the bonding effect of the bonded wafer in the bonding process. The number of bonding holes in the bonded wafer is 0~1, which is considered good. The bonding yield is calculated by the ratio of wafers that meet product requirements to the total wafers.

[0113] The composite film yield (%) mainly reflects the quality of warpage and holes in the final composite film product. Warpage ≤15μm and the number of bonding holes 0~1 are considered good. The composite film yield is calculated by the ratio of wafers that meet product requirements to the total wafers.

[0114] The test results are shown in Table 1 below.

[0115] Table 1 Performance test results of composite substrates of Examples and Comparative Examples

[0116]

[0117] According to the results in Table 1, the wafer warpage and bonding holes are greatly improved by using Examples 1 to 3 of the present technical solution, and the bonding yield and composite film yield are greatly improved.

[0118] Comparing Example 1 with Example 4, it can be seen that when the pressure is too low, the wafer warpage increases, resulting in a decrease in the yield of the composite film and deterioration in quality.

[0119] 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 yield of the composite film and deterioration in quality.

[0120] Comparing Example 1 with Example 6, it can be seen that when the primary heating temperature is too high, wafer voids will increase, resulting in a decrease in bonding yield and composite film yield, and poor quality.

[0121] By comparing 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 deterioration in quality.

[0122] By comparing Example 1 with Example 8, it can be seen that when the secondary heating temperature is too high, a large number of bubbles will form on the wafer in a short time, which will lead to failure in peeling off the composite film, a decrease in the yield of the composite film, and deterioration in quality.

[0123] Comparing Example 1 with Example 9, it can be seen that when the tertiary heating temperature is too low, the composite film is difficult to be completely peeled off, which can easily lead to peeling failure, reduced composite film yield, and poor quality.

[0124] By comparing Example 1 with Example 10, it can be seen that when the tertiary heating temperature is too high, the thermal stress of the composite film peeling is large, which easily leads to the composite film being broken, resulting in a decrease in the yield of the composite film and deterioration in quality.

[0125] By comparing Example 1 with Comparative Example 1, it can be seen that when the non-pressure process is not included, the wafer warpage and the number of bonding holes increase significantly, and the resulting composite film has a low yield and poor quality.

[0126] By comparing Example 1 with Comparative Example 2, it can be seen that in the secondary heating process adopted therein, stress cannot be completely released during the bonding process, resulting in increased warping and bonding holes, which will cause the composite film to easily debond, fail to peel, and break. The resulting composite film has a low yield and poor quality.

[0127] By comparing Example 1 with Comparative Example 3, it can be seen that the method of heating the wafer injection piece adopts the 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, insulation for 30 minutes and no pressure applied during the bonding process will lead to increased wafer warping, thereby causing failure in composite film peeling and a decrease in composite film yield.

[0128] By comparing Example 1 with Comparative Example 4, it can be seen that the temperature of heating the wafer injection piece and the supporting substrate at the same time during the bonding process is too high, which easily leads to incomplete release of thermal stress. In addition, there is no pressure during the bonding process, which significantly increases the warping of the composite film and the bonding holes. During the secondary annealing process, debonding and peeling and breakage occur, resulting in a low yield of the composite film.

[0129] The foregoing is merely an embodiment of the present application, and the scope of protection 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, the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of the present application should be included in the scope of protection 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 sequentially comprises a thin film layer, an implanted layer, and a residual layer; 3) Separating the thin film layer of the wafer implant sheet from the supporting substrate, and positioning the first bonding surface of the wafer implant sheet and the second bonding surface of the supporting substrate relative to each other and aligning them, while heating the wafer implant sheet and the supporting substrate for the first time to 65-75° C., bringing them close to each other and performing a bonding process; 4) applying a first pressure to the first bonding surface and the second bonding surface, wherein the first pressure ranges from 4000 to 6000 N and is maintained for a period of time; 5) reducing the first pressure to a second pressure in the range of 1500-2500N, and performing a second heating at a temperature of 240-280°C and maintaining for 20-40 minutes; 6) Perform a third heating at a temperature of 160-200° C. and keep the temperature for 1.5-3 hours to separate the thin film layer from the residual layer to obtain a composite substrate.

2. The wafer bonding method according to claim 1, wherein: The energy of the ion implantation is 50 to 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.

3. The wafer bonding method according to claim 1, wherein: The thickness of the thin film layer is 100 to 2000 nm.

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

5. The wafer bonding method according to claim 1, wherein: The diameter of the piezoelectric wafer and the supporting substrate is 4 to 12 inches, and the initial thickness is 100 to 1000 μm.

6. Use of the wafer bonding method according to any one of claims 1 to 5 in the preparation of a composite substrate.

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