A preparation process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a hetero thin film bonded substrate

Abstract

This application discloses a fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate, belonging to the field of semiconductor wafer fabrication technology. The process includes the following steps: (1) ion implantation of a rotated tangential lithium niobate wafer, with the ion implantation dose gradually increasing from the center of the wafer outwards; pre-annealing of the substrate wafer; (2) activation and bonding of the ion implantation surface of the lithium niobate wafer obtained in step (1) to the substrate wafer to obtain a bond; (3) a two-step thinning process to reduce the thickness of the lithium niobate wafer to 40-200 μm; (4) annealing of the bond after thinning in step (3) to obtain an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate. This process, by processing the substrate wafer and the lithium niobate wafer, can simultaneously obtain a non-destructive ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate, meeting the current demand for ultrathin lithium niobate piezoelectric single crystal wafers.

Description

Technical Field

[0001] This application relates to a fabrication process for simultaneously obtaining ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates, belonging to the field of semiconductor wafer fabrication technology. Background Technology

[0002] Lithium niobate piezoelectric wafers have excellent piezoelectric properties, high frequency stability, and good temperature stability, making them an important functional material widely used in acoustic filters, sensors, and optoelectronic devices.

[0003] Currently, lithium niobate piezoelectric wafers of conventional thickness are mainly fabricated using wire cutting and laser cutting processes. However, due to the low mechanical strength and high brittleness of lithium niobate material, cutting thin lithium niobate wafers using wire cutting and laser cutting processes significantly reduces the structural stability of the lithium niobate wafers, making them highly susceptible to brittle fracture and leading to a sharp increase in the fragmentation rate. Therefore, although wire cutting and laser cutting technologies are widely used in the processing of wafers of conventional thickness, it is difficult to reliably fabricate high-quality, large-area ultrathin lithium niobate piezoelectric wafers. Currently, there is no reliable method for fabricating ultrathin lithium niobate piezoelectric wafers. This technological bottleneck also restricts the application of ultrathin structures in higher-performance microelectronic devices.

[0004] Lithium niobate piezoelectric wafers of conventional thickness are typically used to fabricate heterogeneous thin-film bonding substrates. The main process involves ion implantation of the lithium niobate wafer to form a thin film layer, an implanted layer, and a residual layer. The thin film layer is then bonded to another substrate wafer. Heating causes the implanted layer to turn into a gas. After peeling off the thin film layer and the residual layer, a heterogeneous thin-film bonding substrate is obtained. Peeling off the thin film layer and the residual layer allows the residual layer to be removed as a separate layer, effectively thinning the lithium niobate piezoelectric wafer. However, the thickness of this residual layer cannot be reduced to below 200 μm, and the peeling process also introduces problems such as fragmentation and cracking. Therefore, currently, regardless of whether wire cutting, laser cutting, or heterogeneous thin-film bonding substrate peeling techniques are used, it is difficult to obtain ultra-thin lithium niobate piezoelectric single-chip wafers. Summary of the Invention

[0005] To address the aforementioned issues, a fabrication process is provided to simultaneously obtain an ultrathin lithium niobate piezoelectric single-chip wafer and a heterogeneous thin-film bonding substrate. This process involves pre-annealing the substrate wafer and controlling the ion implantation concentration of the lithium niobate wafer in different zones. After bonding, the lithium niobate wafer is thinned, and then peeled off to simultaneously obtain a non-destructive ultrathin lithium niobate piezoelectric single-chip wafer and a heterogeneous thin-film bonding substrate, thus meeting the current demand for ultrathin lithium niobate piezoelectric single-chip wafers.

[0006] This application provides a fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin film bonding substrate, comprising the following steps: (1) Ion implantation was performed on the rotated tangential lithium niobate wafer. The ion implantation dose gradually increased from the inside to the outside, with the innermost ion implantation dose being 1×10⁻⁶. 16 -2.0×10 16 ions / cm 2 The outermost ion implantation dose was 2.2 × 10⁻⁶. 16 -4×10 16 ions / cm 2 ; The substrate wafer is pre-annealed at 200-500℃; (2) The ion implantation surface of the lithium niobate wafer obtained in step (1) and the substrate wafer are activated and bonded to obtain a bonded body; (3) The lithium niobate wafer of the bonded structure is thinned to a thickness of 40-200 μm by a two-step thinning process; (4) Anneal the bonded body after thinning in step (3) to obtain an ultrathin lithium niobate piezoelectric single crystal and a heterogeneous thin film bonding substrate.

[0007] This application improves the existing fabrication process of heterogeneous thin-film bonding substrates to simultaneously obtain both heterogeneous thin-film bonding substrates and ultrathin lithium niobate piezoelectric single-chip wafers. However, in the optimization of the aforementioned fabrication process, obtaining ultrathin lithium niobate piezoelectric single-chip wafers requires thinning the bonded lithium niobate wafer, which reveals the following problems: 1. Internal stress in the substrate wafer can cause delamination and fragmentation. During the typical manufacturing process of substrate wafers, internal stress is introduced into the substrate wafers. This internal stress does not affect the bonding with the lithium niobate wafers, so the substrate wafers were not pre-treated before. However, during the improvement of the above-mentioned manufacturing process, it was found that the presence of this internal stress is released during the high-temperature peeling process, which causes the ultrathin lithium niobate piezoelectric single crystal wafer to form fragments or cracks during the peeling process.

[0008] 2. Consistent ion implantation concentrations result in random peeling, generating additional tension on the peeled ultrathin lithium niobate piezoelectric single wafer. Because the ion implantation concentration is consistent throughout the implanted layer, the peeling process of the ultrathin lithium niobate piezoelectric single crystal wafer (ultrathin residual mass layer) is a multi-point random peeling. Therefore, the peeling process will generate additional tensile force on the ultrathin lithium niobate piezoelectric single crystal wafer. Under the presence of this force, the ultrathin lithium niobate piezoelectric single crystal wafer may break, affecting the quality.

[0009] To overcome this defect, the substrate wafer is pre-annealed in step (1) to eliminate its inherent stress, thereby reducing the impact on the lithium niobate wafer during bonding and improving bonding strength while avoiding the introduction of stress into the lithium niobate. In addition, the impact of this internal stress on the ultrathin lithium niobate piezoelectric single crystal wafer during the peeling process in step (4) is reduced, further reducing the peeling fragmentation rate. At the same time, ion implantation is performed on the rotated tangential lithium niobate wafer to obtain an implantation layer with ion concentration gradually increasing from the inside to the outside. This allows for peeling from the outside to the inside during the annealing process in step (4), reducing the generation of additional peeling pull force and further reducing the peeling fragmentation rate.

[0010] Specifically, the ion implantation dose gradually increases from the inside out. This can be achieved by gradually varying the concentration gradient, or by dividing the lithium niobate wafer into different regions with the same ion concentration within each region. Within adjacent regions, the ion concentration on the outer side is higher than that on the inner side. Both methods can simultaneously yield the ultrathin lithium niobate piezoelectric single-layer wafer and the heterogeneous thin-film bonding substrate of this application. Ion implantation is used for the lithium niobate wafer because it forms a neat weakening layer, resulting in higher wafer flatness after stripping.

[0011] Optionally, the implantation surface of the lithium niobate wafer in step (1) includes a central circular region and at least two annular regions surrounding the outer side of the central circular region. The central circular region and at least two annular regions are arranged with the same center.

[0012] This setup divides the lithium niobate wafer into different regions starting from the center. Each region has the same ion implantation concentration, with higher concentrations further away from the center. The more annular regions there are, the more regions can be divided for a lithium niobate wafer of the same size, resulting in more precise ion implantation and smaller differences in ion concentration between adjacent regions. Therefore, the quality of the prepared ultrathin lithium niobate piezoelectric single crystal is better. However, this leads to increased production costs, greater production difficulty, and greater product variability in mass production.

[0013] Optionally, in step (1), the implantation surface of the lithium niobate wafer for ion implantation is, from the inside out, a central circular region, a first annular region, and a second annular region, with the first annular region located between the central circular region and the second annular region.

[0014] Based on the above analysis, and taking into account production quality, production cost, and production process difficulty, the injection surface of the lithium niobate wafer is divided into a central circle and two annular regions. This can meet the current demand for ultra-thin lithium niobate piezoelectric single crystal wafers and improve the consistency of mass-produced products, making it suitable for widespread use.

[0015] Optionally, the diameter ratio of the central circular region, the first annular region, and the second annular region is 1-2:2-3:3-4.

[0016] This diameter ratio setting enables wafer stripping from the outside in.

[0017] Optionally, the ion implantation dose in the central circular region is 1×10⁻⁶. 16 - 2.0×10 16 ions / cm 2 ; The ion implantation dose in the first annular region is 1.8 × 10⁻⁶. 16 -2.3×10 16 ions / cm 2 ; The ion implantation dose in the second annular region is 2.2 × 10⁻⁶. 16 -4×10 16 ions / cm 2 .

[0018] The dosage setting of this ion implantation serves two purposes: first, it enables peeling from the outside in, reducing the fragmentation rate of the ultrathin lithium niobate piezoelectric single crystal wafer; second, it ensures the thickness uniformity of the ultrathin wafer and the heterogeneous thin film substrate after peeling.

[0019] Optionally, for ultrathin lithium niobate, the pre-annealing time of the substrate wafer in step (1) is 4-72 hours.

[0020] The temperature and time of the pre-annealing can effectively release the internal stress in the substrate wafer, while avoiding the reintroduction of internal stress and crystallization damage to the substrate wafer, so as to obtain a high-quality substrate wafer. This high-quality substrate wafer can then be used to obtain a high-quality heterogeneous thin film bonding substrate and an ultrathin lithium niobate piezoelectric single crystal.

[0021] Optionally, the ion implantation uses one of the following ion types: hydrogen ion, helium ion, nitrogen ion, oxygen ion, or hydrogen-helium mixed ion, and the ion implantation energy is 50-500 keV.

[0022] Optionally, the two-step thinning process in step (3) is as follows: S1: Use 1500#-3000# grinding wheels for the first thinning to a thickness of 70-250μm for the lithium niobate wafer; S2: Use 4500#-8000# grinding wheels for a second thinning process until the lithium niobate wafer thickness is 40-200μm.

[0023] The three-step thinning process of steps S1-S3 is based on a special setting of lithium niobate wafers obtained by rotary tangential cutting. If the thickness of the lithium niobate wafer is reduced to less than 70μm in step S1, the surface stress of the lithium niobate wafer will increase, which will easily lead to breakage or cracks during the annealing and peeling process. Therefore, it is necessary to replace the grinding wheel when the thickness is reduced to 70-250μm. By using a finer grinding wheel in step S2 to reduce the lithium niobate wafer to 40-200μm, this effect can be eliminated, and the thinnest lithium niobate piezoelectric single crystal wafer can be obtained. However, the final thinning thickness in step S2 cannot be less than 40μm. If it is less than 40μm, firstly, cracks will be generated during the thinning process, and secondly, step (4) will not be able to be effectively peeled, making it difficult to obtain a whole ultra-thin lithium niobate piezoelectric single crystal wafer.

[0024] Optionally, the surface roughness Ra of the ultrathin lithium niobate piezoelectric single crystal wafer prepared by this method is below 0.5 nm.

[0025] Optionally, the substrate wafer is made of a material selected from silicon carbide, gallium nitride, gallium oxide, diamond, sapphire, or silicon dioxide.

[0026] Optionally, the substrate wafer is made of silicon carbide.

[0027] When the substrate wafer is selected from silicon carbide, the silicon carbide substrate material has higher thermal conductivity and higher thermal stability, which makes the heterogeneous thin film bonding substrate better suited for use in devices.

[0028] Optionally, the size of the substrate wafer and the lithium niobate wafer is at least 2 inches, preferably at least 4 inches, and more preferably 6 inches or more.

[0029] Optionally, the initial thickness of the substrate wafer and the lithium niobate wafer is 200μm-1000μm.

[0030] Optionally, the specific operation of the annealing process in step (4) is as follows: Keep warm at 120-155℃ for 10-20 hours, then at 155-180℃ for 10-15 hours, and then at 180-230℃ for 10-20 hours.

[0031] The annealing temperature is related to the ion implantation concentration of the lithium niobate wafer in step (1). At this temperature, it is possible to quickly and effectively peel off the wafer to obtain a non-destructive ultrathin lithium niobate piezoelectric single wafer. At the same time, it is possible to avoid introducing thermal stress into the ultrathin lithium niobate piezoelectric single wafer and improve the quality of the ultrathin lithium niobate piezoelectric single wafer.

[0032] The beneficial effects of this application include, but are not limited to: 1. According to this application, a fabrication process for both ultrathin lithium niobate piezoelectric single-crystal wafers and heterogeneous thin-film bonding substrates is obtained simultaneously. By controlling the ion implantation concentration of the lithium niobate wafer in different zones, the ultrathin lithium niobate piezoelectric single-crystal wafers can be peeled off from the outside in, reducing the fragmentation rate and improving the surface quality of the ultrathin lithium niobate piezoelectric single-crystal wafers.

[0033] 2. According to this application, a fabrication process for ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates is obtained simultaneously. The two-step thinning process for lithium niobate wafers is based on the rotational tangential setting of the lithium niobate wafers. This operation can obtain ultrathin lithium niobate wafers of 40-200μm, and can reduce the damage to the lithium niobate wafers during the thinning process, thereby improving the yield and product quality.

[0034] 3. According to the preparation process of the ultrathin lithium niobate piezoelectric single crystal and heterogeneous thin film bonding substrate obtained simultaneously, the pre-annealing treatment of the substrate wafer can eliminate the internal stress of the substrate wafer, thereby reducing the influence on the lithium niobate wafer during the bonding process, improving the bonding strength while avoiding the introduction of stress into the lithium niobate, and reducing the influence of the peeling process of the annealing treatment in step (4) on the ultrathin lithium niobate piezoelectric single crystal, further reducing the peeling fragmentation rate.

[0035] 4. According to this application, a fabrication process for both ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates is obtained simultaneously. The fabrication process for heterogeneous thin film bonding substrates is optimized and improved, enabling the simultaneous production of ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates. This meets the industry's demand for both ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates, reduces production costs, and is suitable for industrial-scale promotion and use. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a process flow diagram of the fabrication process of the ultrathin lithium niobate piezoelectric single crystal wafer and heterogeneous thin film bonding substrate involved in Embodiment 3 of this application.

[0037] List of components and reference numerals: 1. Substrate wafer; 2. Lithium niobate wafer; 3. Bonding body; 4. Heterogeneous thin film bonding substrate; 5. Ultrathin lithium niobate piezoelectric single crystal wafer. Detailed Implementation

[0038] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0040] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0041] Example 1 This embodiment relates to a fabrication process for simultaneously obtaining a 2-inch ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate, comprising the following steps: (1) He ion implantation was performed on a rotated tangential lithium niobate wafer (200 μm thick). The ion implantation energy was 50 keV. The He ion implantation dose gradually increased from the center of the wafer outwards. The implantation surface from the center of the wafer outwards consisted of a central circular region, a first annular region, and a second annular region. The first annular region was located between the central circular region and the second annular region. The diameter ratio of the central circular region, the first annular region, and the second annular region was 2:3:4. The ion implantation dose of the central circular region was 1 × 10⁻⁶. 16 ions / cm 2 The ion implantation dose in the first annular region is 1.8 × 10⁻⁶. 16 ions / cm 2 The ion implantation dose in the second annular region was 2.2 × 10⁻⁶. 16 ions / cm 2 ; The silicon substrate wafer (200 μm thick) was pre-annealed at 200 °C for 72 h; (2) Plasma activation and bonding are performed on the He ion implantation surface of the lithium niobate wafer obtained in step (1) and the substrate wafer to obtain a bonded body; (3) The lithium niobate wafer of the bonded structure is thinned to a thickness of 100 μm using a two-step thinning process; the two-step thinning process is as follows: S1: The first thinning was performed using a 1500# grinding wheel until the thickness of the lithium niobate wafer was 70μm; S2: A second thinning process is performed using a 4500# grinding wheel until the lithium niobate wafer thickness is 40μm; (4) The bond body thinned in step (3) is kept at 155°C for 20 hours, then kept at 180°C for 15 hours, and finally annealed at 200°C for 20 hours to obtain an ultrathin lithium niobate piezoelectric single crystal and a heterogeneous thin film bonding substrate.

[0042] Example 2 This embodiment relates to a fabrication process for simultaneously obtaining a 4-inch ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate, comprising the following steps: (1) He ion implantation was performed on a rotated tangential lithium niobate wafer (1000 μm thick). The ion implantation energy was 500 keV, and the He ion implantation dose gradually increased from the inside to the outside. The implantation surface was divided into a central circular region, a first annular region, and a second annular region from the inside to the outside. The first annular region was located between the central circular region and the second annular region. The diameter ratio of the central circular region, the first annular region, and the second annular region was 2:3:4. The ion implantation dose of the central circular region was 2.0 × 10⁻⁶. 16 ions / cm 2 The ion implantation dose in the first annular region was 2.3 × 10⁻⁶. 16 ions / cm 2 The ion implantation dose in the second annular region is 4 × 10⁻⁶. 16 ions / cm 2 ; The silicon carbide substrate wafer (500 μm thick) was pre-annealed at 500 °C for 4 h; (2) The He ion implantation surface of the lithium niobate wafer obtained in step (1) and the silicon carbide substrate wafer are surface activated and bonded to obtain a bonded body; (3) The lithium niobate wafer of the bonded structure is thinned to a thickness of 40 μm using a two-step thinning process; the two-step thinning process is as follows: S1: The first thinning was performed using a 3000# grinding wheel until the thickness of the lithium niobate wafer was 250μm; S2: A second thinning process is performed using an 8000# grinding wheel until the lithium niobate wafer thickness is 200μm; (4) The bonded body after thinning in step (3) is kept at 120°C for 10 hours, then kept at 155°C for 10 hours, and finally kept at 180°C for 10 hours for annealing to obtain an ultrathin lithium niobate piezoelectric single crystal and a heterogeneous thin film bonding substrate.

[0043] Example 3 refer to Figure 1 This embodiment relates to a fabrication process for simultaneously obtaining a 6-inch ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin film bonding substrate, comprising the following steps: (1) He ion implantation was performed on a rotated tangential lithium niobate wafer 2 (thickness 400 μm). The ion implantation energy was 200 keV, and the He ion implantation dose gradually increased from the inside to the outside. The implantation surface was divided into a central circular region, a first annular region, and a second annular region from the inside to the outside. The first annular region was located between the central circular region and the second annular region. The diameter ratio of the central circular region, the first annular region, and the second annular region was 2:3:4. The ion implantation dose of the central circular region was 1.8 × 10⁻⁶. 16 ions / cm 2The ion implantation dose in the first annular region is 2.2 × 10⁻⁶. 16 ions / cm 2 The ion implantation dose in the second annular region was 2.4 × 10⁻⁶. 16 ions / cm 2 ; The silicon carbide substrate wafer 1 (thickness 1000μm) was pre-annealed at 300℃ for 24h; (2) Plasma activation and bonding are performed on the He ion implantation surface of the lithium niobate wafer 2 obtained in step (1) and the silicon carbide substrate wafer 1 to obtain a bonded body 3. (3) The lithium niobate wafer 2 of the bonding body 3 is thinned to a thickness of 60 μm by a two-step thinning process; the two-step thinning process is as follows: S1: The first thinning was performed using a 1500# grinding wheel until the thickness of the lithium niobate wafer 2 was 90μm; S2: A second thinning process was performed using an 8000# grinding wheel until the thickness of the lithium niobate wafer 2 was 60μm; (4) The bond body 3 after thinning in step (3) is kept at 145°C for 20 hours, then kept at 160°C for 10 hours, and finally kept at 185°C for 10 hours for annealing treatment to obtain ultrathin lithium niobate piezoelectric single crystal 5 and heterogeneous thin film bonding substrate 4.

[0044] Example 4 The difference between this embodiment and Embodiment 3 is that the ion implantation dose in both the first and second annular regions is 2.4 × 10⁻⁶. 16 ions / cm 2 The rest is the same as in Example 3.

[0045] Example 5 The difference between this embodiment and embodiment 3 is that the diameter ratio of the central circular region, the first annular region, and the second annular region is 1:2:3, while the rest is the same as in embodiment 3.

[0046] Example 6 The difference between this embodiment and Embodiment 3 is that the specific thinning operation is as follows: S1: The lithium niobate wafer was thinned to a thickness of 60 μm using a 1500# grinding wheel, and the rest was the same as in Example 3.

[0047] Example 7 The difference between this embodiment and embodiment 3 is that in step (4), the bond body thinned in step (3) is annealed at 190°C for 40 hours, while the rest is the same as in embodiment 3.

[0048] Example 8 The difference between this embodiment and embodiment 3 is that, in step (1), the ion implantation dose of He ions into the central circular region of the rotated tangential lithium niobate wafer 2 is 1×10⁻⁶. 16 ions / cm 2 .

[0049] Example 9 The difference between this embodiment and embodiment 3 is that in step (1), He ion implantation is performed on the rotated tangential lithium niobate wafer 2, and the ion implantation dose in the second annular region is 4 × 10⁻⁶. 16 ions / cm 2 .

[0050] Comparative Example 1 The difference between this comparative example and Example 3 is that no pre-annealing treatment is performed on the silicon carbide substrate wafer; that is, the silicon carbide substrate wafer is not treated in any way. Otherwise, it is the same as Example 3.

[0051] Comparative Example 2 The difference between this comparative example and Example 3 is that the SiC substrate wafer was pre-annealed at 600°C for 24 hours, while the rest is the same as Example 3.

[0052] Comparative Example 3 The difference between this comparative example and Example 3 is that the ion implantation dose in the central circular region is 2.4 × 10⁻⁶. 16 ions / cm 2 The rest is the same as in Example 3.

[0053] Comparative Example 4 The difference between this embodiment and embodiment 3 is that in step (1), He ion implantation is performed on the rotated tangential lithium niobate wafer 2, and the ion implantation dose in the second annular region is 4.4 × 10⁻⁶. 16 ions / cm 2 .

[0054] Comparative Example 5 The difference between this comparative example and Example 3 is that the ion implantation dose in the central circle, the first annular region, and the second annular region is 2.2 × 10⁻⁶. 16 ions / cm 2 The rest is the same as in Example 3.

[0055] Test case Ultrathin lithium niobate piezoelectric single crystal wafers and heterogeneous thin film bonding substrates were prepared using the methods described in the above embodiments and comparative examples. Fifty wafers were prepared using each method. The fragmentation rate was calculated, and the thin film layer on the heterogeneous thin film bonding substrate was subjected to TTV test. The test results are shown in Table 1. Fragmentation rate = (number of wafers with fragmentation / 50) * 100%.

[0056] Table 1

[0057] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate, characterized in that, Includes the following steps: (1) Ion implantation is performed on the rotated tangential lithium niobate wafer. The ion implantation dose gradually increases from the center of the wafer outwards, with the innermost ion implantation dose being 1×10⁻⁶. 16 - 2.0×10 16 ions / cm 2 The outermost ion implantation dose was 2.2 × 10⁻⁶. 16 -4×10 16 ions / cm 2 ; The substrate wafer is pre-annealed at 200-500℃; (2) The ion implantation surface of the lithium niobate wafer obtained in step (1) and the substrate wafer are activated and bonded to obtain a bonded body; (3) The lithium niobate wafer of the bonded structure is thinned to a thickness of 40-200 μm by a two-step thinning process; (4) Anneal the bonded body after thinning in step (3) to obtain an ultrathin lithium niobate piezoelectric single crystal and a heterogeneous thin film bonding substrate.

2. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, Step (1) The implantation surface for ion implantation of the lithium niobate wafer includes a central circular region and at least two annular regions surrounding the outer side of the central circular region in sequence; The central circular region and at least two annular regions are arranged with the same center.

3. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 2, characterized in that, Step (1) The implantation surface for ion implantation of lithium niobate wafer is, from the center of the wafer outward, a central circular region, a first annular region and a second annular region, with the first annular region located between the central circular region and the second annular region.

4. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 3, characterized in that, The diameter ratio of the central circular region, the first annular region, and the second annular region is 1-2:2-3:3-4.

5. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 3, characterized in that, The ion implantation dose in the central circular region is 1×10⁻⁶. 16 - 2.0×10 16 ions / cm 2 ; The ion implantation dose in the first annular region is 1.8 × 10⁻⁶. 16 -2.3×10 16 ions / cm 2 ; The ion implantation dose in the second annular region is 2.2 × 10⁻⁶. 16 -4×10 16 ions / cm 2 .

6. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, Step (1) The pre-annealing time for the substrate wafer is 4-72 hours.

7. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, The two-step thinning process in step (3) is as follows: S1: Use 1500#-3000# grinding wheels for the first thinning to a thickness of 70-250μm for the lithium niobate wafer; S2: Use 4500#-8000# grinding wheels for a second thinning process until the lithium niobate wafer thickness is 40-200μm.

8. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, The substrate wafer is made of a material selected from silicon carbide, silicon, spinel, gallium nitride, gallium oxide, diamond, sapphire, or silicon dioxide.

9. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, The specific operation of step (4) annealing is as follows: Keep warm at 120-155℃ for 10-20 hours, then at 155-180℃ for 10-15 hours, and then at 180-200℃ for 10-20 hours.

10. The fabrication process for simultaneously obtaining an ultrathin lithium niobate piezoelectric single crystal wafer and a heterogeneous thin-film bonding substrate according to claim 1, characterized in that, The size of the substrate wafer and the lithium niobate wafer is 2 inches or larger.

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