Wafer composite film and preparation method thereof

Abstract

The invention discloses a wafer composite film and a preparation method thereof, and belongs to the technical field of semiconductor preparation. The method comprises the following steps: (1) performing hydrogen ion or hydrogen-helium mixed ion implantation on a piezoelectric wafer to obtain an implanted wafer, wherein the implanted wafer sequentially comprises a thin film layer, an implanted layer and a residual layer; (2) sequentially forming a defect layer and an isolation layer on the supporting substrate; (3) bonding the isolation layer and the thin film layer of the injected wafer to obtain a bonding body; and (4) laser is adopted to heat the injection layer, then annealing heat treatment is carried out on the bonding body to achieve complete stripping, polishing and cleaning of the film, then the wafer composite film is obtained, the wavelength of the laser is 100-700 nm, the power of the laser is 50 mw to 100 w, and the scanning speed of the laser is 10-50 mm / s. According to the method, complete stripping of the composite film and combination of laser and thermal annealing processes can be effectively achieved, the method has high process stability, the yield of the composite film can be greatly improved, and the processing time cost of the composite film is shortened.

Description

Technical Field

[0001] The present application relates to a wafer composite film and a preparation method thereof, belonging to the technical field of semiconductor preparation. Background Art

[0002] Piezoelectric wafers such as lithium niobate or lithium tantalate have the advantages of high Curie temperature, strong spontaneous polarization, high electromechanical coupling coefficient, excellent electro-optic effect, etc., and are widely used in the fields of nonlinear optics, ferroelectricity, piezoelectricity, electro-optics, etc. In recent years, composite films on insulators have attracted the attention and emphasis of the industrial community. Its structure can be simply understood as a three-layer structure, including the top functional layer, the middle dielectric layer, and the semiconductor support substrate. The active layer can be a piezoelectric film such as lithium niobate and lithium tantalate. Currently, the methods for preparing lithium niobate or lithium tantalate piezoelectric composite films mainly include the ion beam separation method and the thinning and polishing method.

[0003] Among them, when preparing a composite film by the ion beam separation method, the bonded body after bonding the support substrate and the piezoelectric wafer after ion implantation needs to be annealed, so as to retain the thin film layer on the substrate layer to prepare a piezoelectric composite film. However, in the actual annealing process, since the piezoelectric wafer and the support substrate are usually heterogeneous materials and there are differences in the thermal expansion coefficients, warping of the bonded body occurs during the heating process, generating a large force on the piezoelectric film, which in turn causes the composite film to break, increasing the production cost of the composite film.

[0004] To solve this problem, Patent CN118969628A discloses a method for preparing a thin film wafer based on laser peeling of a heterogeneous substrate crystal film. It uses a laser to focus on the implantation stop layer of the lithium niobate thin film sheet, so that the implanted layer is quickly heated to achieve peeling. At the same time, the thin film wafer and the substrate material far from the implanted layer are slowly heated, simply and efficiently solving the problem of fragmentation caused by the overall heating of the bonded wafers, and realizing the complete peeling of the thin film under the condition that the thermal expansion coefficients of the substrate and the thin film are inconsistent. The applicant found that during the above laser peeling process, since the laser can cause the focused part to be quickly heated to achieve peeling, there is a situation where the top of the wafer implanted layer is peeled off but the bottom has not been peeled off during the laser scanning. This situation will introduce a large peeling stress, thereby reducing the yield of the composite film preparation. At the same time, the rapid heating of the laser makes the instantaneous temperature reach 400°C to 600°C. Since the thickness of the composite film is generally less than 2 μm and is very close to the bonding layer, it will cause the bonded body to be debonded, thus affecting the preparation of the composite film. Therefore, it is necessary to develop a new method for preparing a composite film to solve the above problems. Summary of the Invention

[0005] To solve the above problems, a method for preparing a wafer composite film is provided. In this method, the injection layer of the bonded body is first heated by laser, so that tiny bubbles are formed between the thin film layer and the residual layer but do not detach. Then, it is peeled off by annealing treatment, which can effectively achieve the complete peeling of the composite film. The combination of laser and thermal annealing processes has high process stability, can greatly improve the yield of the composite film, and shorten the time cost of composite film processing.

[0006] According to one aspect of the present application, a method for preparing a wafer composite film is provided, including the steps of:

[0007] (1) Performing hydrogen ion or hydrogen-helium mixed ion implantation on a piezoelectric wafer to obtain an implanted wafer, where the implanted wafer sequentially includes a thin film layer, an injection layer, and a residual layer;

[0008] (2) Sequentially forming a defect layer and an isolation layer on a support substrate;

[0009] (3) Bonding the isolation layer with the thin film layer of the implanted wafer to obtain a bonded body;

[0010] (4) Heating the injection layer with a laser, and then performing annealing treatment on the bonded body. After polishing and cleaning, a wafer composite film is obtained. The wavelength of the laser is 100 - 700 nm, the power is 50 mw - 1 w, and the scanning speed is 10 - 50 mm / s.

[0011] After hydrogen ion or hydrogen-helium mixed ion implantation, a thin film layer, an injection layer, and a residual layer are formed. These two ions can reduce the lattice damage to the thin film layer and the total thickness deviation of the thin film layer, thereby improving the uniformity of the composite film; at the same time, they can also make the thickness of the injection layer moderate. In step (4), the injection layer is heated with a laser, and the core parameters such as the wavelength and power of the laser are precisely controlled, so that a large number of bubbles can be formed by the ions in the injection layer in a short time. Then, annealing treatment is performed on the bonded body to achieve the complete peeling of the thin film, and the stress of the thin film layer can also be reduced.

[0012] Optionally, the annealing treatment in step (4) is:

[0013] Primary annealing treatment: the temperature is 100 - 300 °C, and the annealing time is 1 min - 60 min;

[0014] Secondary annealing treatment: the temperature is 350 °C - 500 °C, and the annealing time is 1 - 8 h.

[0015] The above annealing treatment is carried out in two steps. The primary annealing can achieve the peeling of the thin film, and the secondary annealing can repair the lattice damage caused by ion implantation. And the above secondary heat treatment annealing can reduce the stress of the composite film and improve the quality of the composite film.

[0016] Optionally, the energy for hydrogen ion implantation in step (1) is 50 keV to 1000 keV, and the dose is 3×10 15 ions / cm 2 ~2×10 18 ions / cm 2 .

[0017] More preferably, the implantation can be carried out in 3 to 10 steps. The energy for each implantation remains unchanged, and the dose is evenly distributed according to the total required dose. For example, if the required implantation energy is 200 keV and the dose is 8×10 16 ions / cm 2 , when it is divided into 10 times of implantation, the energy for each implantation is 200 keV, and the dose is 8×10 15 ions / cm 2 . Multiple implantations will reduce the warping of the wafer during the ion implantation process and improve the uniformity of the thin film; during the ion implantation process, the ion beam is sprayed with the particle beam generated by the shower head to reduce the surface particles of the implanted wafer.

[0018] The greater the energy of hydrogen ion implantation, the deeper the depth of the implanted layer, and vice versa, the shallower the depth of the implanted layer.

[0019] Optionally, when performing hydrogen-helium mixed ion implantation in step (1), the ratio of hydrogen ions to helium ions is 1:(2 - 5).

[0020] Under this setting, the total ion dose required for implantation can be significantly reduced, and the temperature required for annealing can also be reduced.

[0021] Preferably, the energy for hydrogen-helium mixed ion implantation is 50 keV to 1000 keV, and the dose is 3×10 15 ions / cm 2 ~8×10 16 ions / cm 2 .

[0022] More preferably, the implantation can be carried out in 3 to 10 steps. The energy for each implantation remains unchanged, and the dose is evenly distributed according to the total required dose. For example, if the required implantation energy is 150 keV and the dose is 6×10 15 ions / cm 2 , when it is divided into 3 times of implantation, the energy for each implantation is 150 keV, and the dose is 2×10 15 ions / cm 2 . Multiple implantations will reduce the warping of the wafer during the ion implantation process and improve the uniformity of the thin film; during the ion implantation process, the ion beam is sprayed with the particle beam generated by the shower head to reduce the surface particles of the implanted wafer.

[0023] Similarly, the greater the energy of the hydrogen-helium mixed ion implantation, the deeper the depth of the implanted layer; conversely, the shallower the depth of the implanted layer. With this setting, the depth of the implanted layer can be made appropriate, facilitating the peeling of the thin film layer and the residual layer, so as to obtain a composite film with complete peeling and more stable performance.

[0024] The energy of ion implantation also affects the thickness of the thin film layer. The greater the implantation energy, the greater the thickness of the thin film layer; the smaller the implantation energy, the smaller the thickness of the thin film layer. With the above settings, the thickness of the thin film layer can be within the range of 100 nm to 3000 nm to meet the usage requirements of the composite film.

[0025] Optionally, the thickness of the thin film layer is 100 nm to 3000 nm, the surface roughness of the thin film layer is less than 0.5 nm, and the warpage and curvature of the composite film are less than 20 μm.

[0026] Optionally, the material of the isolation layer is at least one of silicon dioxide, silicon oxynitride, and silicon nitride, the thickness of the isolation layer is 100 nm to 5000 nm, and the surface roughness of the isolation layer is less than 1 nm.

[0027] Optionally, the material of the defect layer is at least one of polysilicon, amorphous silicon, and polycrystalline germanium, and the thickness of the defect layer is 100 nm to 3000 nm.

[0028] Optionally, the piezoelectric wafer is one of lithium niobate, lithium tantalate, quartz, lithium tetraborate, and lanthanum gallium silicate;

[0029] The support substrate is at least one of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide, preferably silicon.

[0030] Optionally, the initial thickness of the piezoelectric wafer and the support substrate is 100 μm to 1000 μm, and the diameter of the piezoelectric wafer and the support substrate is 3 inches to 12 inches.

[0031] Preferably, the thickness of the support substrate is 625 μm.

[0032] Optionally, the defect layer is formed by a deposition method, and the isolation layer is formed by a deposition method or an oxidation method. The formation method of the deposition method is not limited and can be chemical vapor deposition (CVD), physical vapor deposition (PVD), magnetron sputtering, etc.

[0033] According to another aspect of the present application, there is provided a wafer composite film prepared by the preparation method of the wafer composite film described in any one of the above.

[0034] The beneficial effects of the present application include but are not limited to:

[0035] 1. In the method for preparing a wafer composite film according to the present application, the injection layer is preliminarily heated by laser, during which the support substrate and the piezoelectric wafer are not heated. Then, the overall bonded body is subjected to annealing heat treatment, which can avoid the fracture of the composite film caused by the difference in thermal expansion coefficients between the piezoelectric wafer and the support substrate during annealing separation, improve the yield rate of the piezoelectric composite film, and reduce the production cost of the composite film. Moreover, it can avoid the debonding of the bonded body caused by too high laser temperature, thereby improving the yield rate of the composite film.

[0036] 2. In the method for preparing a wafer composite film according to the present application, by controlling the wavelength, power, and scanning speed of the laser to heat the injection layer, it can ensure that tiny bubbles are uniformly arranged on the surface where the injection layer contacts the film layer and the residual layer, laying a foundation for subsequent annealing heat treatment. In the subsequent annealing heat treatment, the annealing time can be reduced, greatly shortening the time cost, and at the same time improving the uniformity of the film.

[0037] 3. In the method for preparing a wafer composite film according to the present application, by using hydrogen ions or a hydrogen-helium mixed ion for ion implantation to obtain an implanted wafer, the total ion dose required for implantation can be significantly reduced, and the temperature required for annealing can be reduced.

[0038] 4. In the method for preparing a wafer composite film according to the present application, annealing is used in the annealing heat treatment to achieve the peeling of the film and repair the lattice damage caused by ion implantation. The temperature of the first annealing is 100 - 300 °C to achieve the peeling of the film, and the temperature of the second annealing is 350 - 500 °C to repair the lattice damage caused by ion implantation. Moreover, the above two-step heat treatment annealing can reduce the stress of the composite film and improve the quality of the composite film.

[0039] 5. In the method for preparing a wafer composite film according to the present application, the ratio, energy, and dose of the hydrogen-helium mixed ion can make the depth of the injection layer appropriate, so as to facilitate the peeling of the film layer and the residual layer, in order to obtain a composite film with complete peeling and more stable performance. Description of the Drawings

[0040] The drawings described herein are used to provide a further understanding of the present application and form 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:

[0041] Figure 1 It is a schematic flow chart of the preparation of the composite film according to the embodiment of the present application.

[0042] Figure 2 It is a schematic structural flow chart of the preparation of the composite film according to the embodiment of the present application.

[0043] Figure 3Schematic diagram of the laser heating injection layer scanning method for preparing a composite film according to an embodiment of the present application.

[0044] List of components and reference numerals:

[0045] 110 - Piezoelectric wafer, 1101 - Thin film layer, 1102 - Injection layer, 1103 - Residual layer, 120 - Support substrate, 1301 - Defect layer, 1302 - Isolation layer, 140 - Bonded body, 1401 - Injection layer with bubbles. Detailed implementation manners

[0046] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0047] Unless otherwise specified, the raw materials in the embodiments and comparative examples of the present application are purchased through commercial channels.

[0048] Unless otherwise specified, the methods used in the embodiments and comparative examples of the present application are conventional methods in the prior art.

[0049] Embodiment

[0050] Reference Figure 1 , this embodiment relates to a method for preparing a wafer composite film, including the steps of:

[0051] (1) Performing hydrogen ion or hydrogen - helium mixed ion implantation on the piezoelectric wafer 110 to obtain an implanted wafer, and the implanted wafer sequentially includes a thin film layer 1101, an injection layer 1102, and a residual layer 1103;

[0052] (2) Sequentially forming a defect layer 1301 and an isolation layer 1302 on the support substrate 120;

[0053] (3) Bonding the isolation layer 1302 with the thin film layer 1101 of the implanted wafer to obtain a bonded body 140;

[0054] (4) Heating the injection layer 1102 by laser, and then performing annealing treatment on the bonded body 140, removing the residual layer 1103, polishing, and cleaning to obtain a wafer composite film. The wavelength of the laser is 100 - 700 nm, the power is 50 mw - 1 w, and the scanning speed is 10 - 50 mm / s.

[0055] Specifically, the bonding method in this application is not particularly limited, and any bonding method in the prior art can be adopted. For example, surface activation bonding can be used. The bonding surface of the thin film layer 1101 of the piezoelectric wafer 110 is surface-activated, and the bonding surface of the isolation layer 1302 supporting the composite substrate is also surface-activated. Then, the two activated surfaces are bonded to obtain the bonded body 140. The surface activation method in this application is not limited either. For example, methods such as plasma activation or chemical solution activation can be used.

[0056] As an implementation method, after activating the thin film layer 1101 and the isolation layer 1302 by plasma activation and then bonding them, the parameters of plasma activation are that the vacuum degree of the plasma activation chamber does not exceed 1×10 -2 Pa, the flow rate of the oxygen plasma gas used is 100 - 500 sccm, the flow rate of the nitrogen plasma gas is 100 - 500 sccm, the power of the plasma emitter is 10 - 500 W, and the process time is 15 - 90 s.

[0057] Specifically, the direction and number of laser scans when laser-heating the injection layer 1102 in this application are not specifically limited. Referring to Figure 3 , this application gives several schematic diagrams of scanning methods. For example, Figure 3 (a) Scanning is performed in a direction perpendicular to the positioning flat edge. Figure 3 (b) Scanning is performed at a certain angle to the positioning flat edge. Figure 3 (c) Scanning is performed twice at a certain angle to the positioning flat edge. Figure 3 (d) Scanning is performed twice in directions perpendicular and parallel to the positioning flat edge.

[0058] Specifically, the polishing method in this application is not particularly limited, and any polishing method in the prior art can be adopted. For example, chemical mechanical polishing can be used for polishing. The cleaning method in this application is not limited either. For example, the standard semiconductor RCA cleaning method can be used for cleaning.

[0059] As an implementation method, the annealing heat treatment in step (4) is as follows:

[0060] First annealing heat treatment: the temperature is 100 - 300 °C, and the annealing time is 1 min - 60 min;

[0061] Second annealing heat treatment: the temperature is 350 °C - 500 °C, and the annealing time is 1 - 8 h.

[0062] As an implementation method, the energy of hydrogen ion implantation in step (1) is 50 KeV - 1000 KeV, and the dose is 3×10 15 ions / cm2 ~2×10 18 ions / cm 2 。

[0063] As an implementation manner, when performing hydrogen-helium mixed ion implantation in step (1), the ratio of hydrogen ions to helium ions is 1:(2-5).

[0064] As an implementation manner, the energy of the hydrogen-helium mixed ion implantation is 50 keV - 1000 keV, and the dose is 3×10 15 ions / cm 2 ~8×10 16 ions / cm 2 。

[0065] As an implementation manner, the thickness of the thin film layer 1101 is 100 nm - 3000 nm, and the surface roughness of the thin film layer 1101 is less than 0.5 nm.

[0066] As an implementation manner, the material of the isolation layer 1302 is at least one of silicon dioxide, silicon oxynitride, and silicon nitride, the thickness of the isolation layer 1302 is 100 nm - 5000 nm, and the surface roughness of the isolation layer 1302 is less than 1 nm.

[0067] As an implementation manner, the material of the defect layer 1301 is at least one of polycrystalline silicon, amorphous silicon, and polycrystalline germanium, and the thickness of the defect layer 1301 is 100 nm - 3000 nm.

[0068] As an implementation manner, the piezoelectric wafer 110 is one of lithium niobate, lithium tantalate, quartz, lithium tetraborate, and lanthanum gallium silicate;

[0069] The support substrate 120 is at least one of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide.

[0070] As an implementation manner, the initial thickness of the piezoelectric wafer 110 and the support substrate 120 is 100 μm - 1000 μm, and the diameters of the piezoelectric wafer 110 and the support substrate 120 are 3 inches - 12 inches.

[0071] According to the above preparation method, the following composite film is as follows:

[0072] Composite film 1#:

[0073] (1) Provide a 3-inch, 100-μm lithium tantalate wafer and a silicon carbide wafer, perform semiconductor-grade RCA cleaning on both wafers to obtain wafers with a clean surface, and perform hydrogen ion implantation on the lithium tantalate wafer, and the implantation dose is 5×10 16 ions / cm 2, with an injection energy of 180 keV, a three-layer structure injection wafer with a thin film layer, an injection layer, and a residual layer is formed;

[0074] (2) On the cleaned silicon carbide wafer, polysilicon is deposited by LPCVD process to form a defect layer. The deposition temperature is controlled at 610 °C and the deposition thickness is 100 nm. Then, a silicon dioxide layer is deposited on the polysilicon by PECVD method to form an isolation layer, and the deposition thickness is 100 nm. Then, chemical mechanical polishing is carried out to obtain a smooth surface, and finally RCA cleaning is carried out to obtain a clean surface;

[0075] (3) Plasma surface activation treatment is carried out on the thin film layer of the injection wafer with a clean surface and the isolation layer of the silicon carbide wafer. The parameters of plasma activation are that the vacuum degree of the plasma activation chamber does not exceed 1×10 -2 Pa, the flow rate of the oxygen plasma gas used is 100 sccm, the flow rate of the nitrogen plasma gas is 500 sccm, the power of the plasma emitter is 10 W, the process time is 90 s, and the activated wafers are bonded together at room temperature to form a bonded body;

[0076] (4) The injection layer of the bonded body is scanned with a laser with a wavelength of 100 nm, the power of the laser is 1 w, and the scanning is carried out in a way perpendicular to the positioning flat edge. The scanning speed is 10 mm / s. Then, the bonded body is annealed until the thin film layer and the residual layer are separated. The annealing treatment is specifically as follows: the first annealing treatment: the temperature is 100 °C and the annealing time is 2 h; the second annealing treatment: the temperature is 350 °C and the annealing time is 8 h; the residual layer is removed to obtain a lithium tantalate composite film. The lithium tantalate composite film is fixed on the porous ceramic chuck of the polishing equipment, and then chemical mechanical polishing treatment is carried out. Finally, semiconductor-grade RCA cleaning is carried out to obtain composite film 1#.

[0077] Composite film 2#

[0078] (1) Provide a 4-inch, 1000-μm lithium niobate wafer and a silicon wafer, and perform semiconductor-grade RCA cleaning on the two wafers to obtain wafers with clean surfaces. Hydrogen ions are injected into the lithium niobate wafer, and the injection dose is 2×10 16 ions / cm 2 , with an injection energy of 250 keV, a three-layer structure injection wafer with a thin film layer, an injection layer, and a residual layer is formed;

[0079] (2) Deposit polysilicon on the cleaned silicon carbide wafer by LPCVD process to form a defect layer. The deposition temperature is controlled at 580 °C and the deposition thickness is 500 nm. Then, prepare a silicon dioxide layer on the polysilicon by oxidation method to form the isolation layer 1302 with a thickness of 5000 nm. Then, perform chemical mechanical polishing to obtain a smooth surface, and finally perform RCA cleaning to obtain a clean surface;

[0080] (3) Perform plasma surface activation treatment on the thin film layer 1101 of the implanted wafer with a clean surface and the isolation layer 1302 of the silicon wafer 120. The parameters of plasma activation are that the vacuum degree of the plasma activation chamber does not exceed 1×10 -2 Pa, the flow rate of the oxygen plasma gas used is 500 sccm, the flow rate of the nitrogen plasma gas is 100 sccm, the power of the plasma emitter is 500 W, the process time is 15 s, and bond the activated wafers together at room temperature to form a bonded body.

[0081] (4) Scan the implanted layer of the bonded body with a laser with a wavelength of 700 nm. The power of the laser is 50 mw. Scan in a way that forms a 30-degree angle with the positioning flat edge, and the scan speed is 50 mm / s. Then, perform annealing heat treatment on the bonded body until the thin film layer and the residual layer are separated. The annealing heat treatment is specifically as follows: primary annealing heat treatment: the temperature is 300 °C and the annealing time is 1 min; secondary annealing heat treatment: the temperature is 500 °C and the annealing time is 1 h; remove the residual layer to obtain a lithium niobate composite thin film, fix the lithium niobate composite thin film on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform semiconductor-grade RCA cleaning to obtain the composite thin film 2#.

[0082] Composite film 3#:

[0083] (1) Provide a 6-inch, 100-μm lithium niobate wafer and a silicon wafer, and perform semiconductor-grade RCA cleaning on both wafers to obtain wafers with clean surfaces. Perform hydrogen ion implantation on the lithium niobate wafer, and the implantation dose is 6×10 16 ions / cm 2 , and the implantation energy is 100 KeV to form a three-layer structure implanted wafer with a thin film layer, an implanted layer, and a residual layer;

[0084] (2) Deposit polysilicon on the cleaned silicon carbide wafer by LPCVD process to form a defect layer 1301. The deposition temperature is controlled at 600 °C and the deposition thickness is 3000 nm. Then, deposit a silicon dioxide layer on the polysilicon by PECVD to form the isolation layer 1302 with a thickness of 800 nm. Then, perform chemical mechanical polishing to obtain a smooth surface, and finally perform RCA cleaning to obtain a clean surface;

[0085] (3) Perform plasma surface activation treatment on the thin film layer of the implanted wafer with a clean surface and the isolation layer of the silicon wafer. The parameters of plasma activation are that the vacuum degree of the plasma activation chamber does not exceed 1×10 -2 Pa, the flow rate of the oxygen plasma gas used is 300 sccm, the flow rate of the nitrogen plasma gas is 350 sccm, the power of the plasma emitter is 300 W, the process time is 65 s, and the activated wafers are bonded together at room temperature to form a bonded body.

[0086] (4) Use a laser with a wavelength of 400 nm to scan the implanted layer of the bonded body. The power of the laser is 1 W. Perform two scans in a manner parallel and perpendicular to the positioning flat edge. The scan speed is 20 mm / s. Then, perform annealing heat treatment on the bonded body until the thin film layer and the residual layer are separated. The annealing heat treatment is specifically as follows: the first annealing heat treatment: the temperature is 200 °C, and the annealing time is 1 h; the second annealing heat treatment: the temperature is 450 °C, and the annealing time is 5 h; remove the residual layer to obtain a lithium niobate composite thin film. Fix the lithium niobate composite thin film on the porous ceramic chuck of the polishing equipment, then perform chemical mechanical polishing treatment, and finally perform semiconductor-grade RCA cleaning to obtain composite thin film 3#.

[0087] Composite film 4#:

[0088] The difference between this composite thin film and composite thin film 3# is that in step (1), hydrogen-helium mixed ion implantation is used, the ratio of hydrogen ions to helium ions is 1:5, and the implantation dose is 8×10 16 ions / cm 2 , the implantation energy is 50 keV, and the rest is the same as that of composite thin film 3#.

[0089] Composite film 5#:

[0090] The difference between this composite thin film and composite thin film 3# is that in step (1), hydrogen-helium mixed ion implantation is used, the ratio of hydrogen ions to helium ions is 1:2, and the implantation dose is 3×10 15 ions / cm 2 , the implantation energy is 1000 keV, and the rest is the same as that of composite thin film 3#.

[0091] Composite film 6#:

[0092] The difference between this composite thin film and composite thin film 5# is that the ratio of hydrogen ions to helium ions is 1:1, and the rest is the same as that of composite thin film 5#.

[0093] Composite film 7#:

[0094] The difference between this composite film and composite film 5# is that the hydrogen-helium mixed ion implantation dose is 10×10 16 ions / cm 2 , the implantation energy is 50 KeV, and the rest is the same as that of composite film 5#.

[0095] Composite film 8#:

[0096] The difference between this composite film and composite film 3# is that the annealing heat treatment is specifically as follows: the first annealing heat treatment: the temperature is 450 °C and the annealing time is 5 h; the second annealing heat treatment: the temperature is 200 °C and the annealing time is 1 h, and the rest is the same as that of composite film 3#.

[0097] Composite film 9#:

[0098] The difference between this composite film and composite film 3# is that only one annealing heat treatment is carried out: annealing at 300 °C for 6 h, and the rest is the same as that of composite film 3#.

[0099] Composite film 10#:

[0100] The difference between this composite film and composite film 3# is that in step (1), the hydrogen ion implantation is carried out in 10 times, the implantation energy for each time is 100 KeV, and the implantation dose is 6×10 15 ions / cm 2 , and the rest is the same as that of composite film 3#.

[0101] Composite film 11#:

[0102] The difference between this composite film and composite film 5# is that in step (1), the hydrogen-helium mixed ion implantation is carried out in 3 times, the implantation energy for each time is 1000 KeV, and the implantation dose is 1×10 15 ions / cm 2 , and the rest is the same as that of composite film 5#.

[0103] Comparative composite film D1#:

[0104] The difference between this comparative composite film and composite film 3# is that in step (1), helium ion implantation is adopted, the implantation dose is 5×10 16 ions / cm 2 , and the implantation energy is 200 KeV.

[0105] Comparative composite film D2#:

[0106] The difference between this comparative composite film and composite film 3# is that in step (4), the bonded body is not laser scanned and the annealing heat treatment operation is directly carried out.

[0107] Comparative composite film D3#:

[0108] The difference between this comparative composite film and composite film 3# is that in step (4), only the injection layer of the bonded body is scanned with a laser. The power of the laser is 2w, and two scans are performed in a manner parallel and perpendicular to the positioning flat edge. The scanning speed is 20mm / s, and the annealing heat treatment operation is no longer carried out.

[0109] Test example

[0110] The film layer thickness of each composite film prepared in the examples was tested, and the test results are shown in Table 1. The total thickness deviation, yield, warpage degree, and curvature of the composite film were also tested, and the test results are shown in Table 1.

[0111] Table 1

[0112]

[0113]

[0114] As described above, only the embodiments of the present application are concerned. 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 changes and modifications can be made to the present application. Any modifications, equivalent replacements, improvements, 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 method for preparing a wafer composite film, characterized in that, Including the steps: (1) Hydrogen ions or hydrogen-helium mixed ions are implanted into a piezoelectric wafer to obtain an implanted wafer, and the implanted wafer sequentially includes a thin film layer, an implanted layer, and a residual layer; (2) A defect layer and an isolation layer are sequentially formed on a support substrate; (3) The isolation layer is bonded to the thin film layer of the implanted wafer to obtain a bonded body; (4) The implanted layer is heated by a laser, and then the bonded body is subjected to annealing heat treatment. After polishing and cleaning, a wafer composite film is obtained. The wavelength of the laser is 100 - 700 nm, the power is 50 mw - 1 w, and the scanning speed is 10 - 50 mm / s.

2. The preparation method according to claim 1, characterized in that, The annealing heat treatment in step (4) is specifically: Primary annealing heat treatment: the temperature is 100 - 300 °C, and the annealing time is 1 min - 60 min; Secondary annealing heat treatment: the temperature is 350 - 500 °C, and the annealing time is 1 - 8 h.

3. The preparation method according to claim 1, wherein, The energy of hydrogen ion implantation in step (1) is 50 keV to 1000 keV, and the dose is 3×10 15 ions / cm 2 ~2×10 18 ions / cm 2 .

4. The preparation method according to claim 1, characterized in that, When performing hydrogen-helium mixed ion implantation in step (1), the ratio of hydrogen ions to helium ions is 1:(2 - 5); Preferably, the energy of hydrogen-helium mixed ion implantation is 50 KeV - 1000 KeV, and the dose is 3× 10 15 ions / cm 2 ~8×10 16 ions / cm 2 。 5. The preparation method according to claim 1, characterized in that, The thickness of the thin film layer is 100 nm - 3000 nm, the surface roughness is less than 0.5 nm, and the warpage and curvature of the composite film are both less than 20 μm.

6. The preparation method according to claim 1, characterized in that, The material of the isolation layer is at least one of silicon dioxide, silicon oxynitride, and silicon nitride. The thickness of the isolation layer is 100 nm - 5000 nm, and the surface roughness of the isolation layer is less than 1 nm.

7. The preparation method according to claim 1, wherein The material of the defect layer is at least one of polycrystalline silicon, amorphous silicon, and polycrystalline germanium. The thickness of the defect layer is 100 nm - 3000 nm.

8. The preparation method according to claim 1, wherein The piezoelectric wafer is one of lithium niobate, lithium tantalate, quartz, lithium tetraborate, and lanthanum gallium silicate; The support substrate is at least one of sapphire, silicon, silicon carbide, quartz, diamond, gallium nitride, and gallium arsenide.

9. The preparation method according to claim 1, wherein The initial thickness of the piezoelectric wafer and the support substrate is 100 μm - 1000 μm, and the diameter of the piezoelectric wafer and the support substrate is 3 inches - 12 inches.

10. A wafer composite film prepared by the method for preparing a wafer composite film according to any one of claims 1 - 9.

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