A method for secondary ion implantation of a thin film wafer, a composite thin film, and an electronic component

Abstract

The present application discloses a method for secondary ion implantation of thin film wafers, a composite thin film and an electronic component, the method comprising: preparing a thin film wafer and a non-homogeneous substrate wafer; performing two ion implantation processes on the thin film wafer, wherein the difference between the depth of the first ion implantation and the depth of the second ion implantation is 20nm-200nm, and obtaining a thin film wafer implantation sheet comprising a four-layer structure of a residual substance layer, a first implantation layer, a second implantation layer and a thin film layer; performing bonding on the thin film wafer implantation sheet and the non-homogeneous substrate wafer to obtain a bonded body; performing heat treatment on the bonded body to obtain a separation bubble layer; peeling off the residual substance layer at the separation bubble layer, so that the residual substance layer is separated from the thin film layer to obtain a composite thin film. The present application uses secondary ion implantation to prevent the thin film wafer and the substrate wafer from having a large difference in thermal expansion coefficient, which will not cause the thin film layer to burst, thereby improving the finished product yield of the thin film wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials and optoelectronic materials, and in particular to a secondary ion implantation method for a thin film wafer, a composite thin film and an electronic component. Background Art

[0002] Thin film wafers such as lithium niobate or lithium tantalate are widely used in the manufacture of filters, optical waveguide modulators, optical waveguide switches, spatial light modulators, optical frequency multipliers, surface acoustic wave generators, infrared detectors and ferroelectric memories due to their advantages such as high Curie temperature, strong spontaneous polarization, high electromechanical coupling coefficient and excellent electro-optical effect, and have broad application prospects.

[0003] Currently, the methods used to prepare lithium niobate or lithium tantalate thin films mainly include epitaxial growth, ion implantation and bond separation, and ion implantation and grinding and polishing. Among them, ion implantation and bond separation is the most widely used method. This method mainly injects ions into a thin film wafer such as lithium niobate or lithium tantalate, dividing the thin film wafer into a thin film layer, a separation layer, and a residual layer. Then, the ion implanted surface of the thin film wafer is bonded to the substrate layer to form a bonded structure. Finally, the bonded structure is heat-treated to separate the residual layer from the thin film layer, leaving the thin film layer on the substrate layer, thereby producing a thin film layer with performance close to that of the thin film wafer.

[0004] However, during the aforementioned fabrication process, if the thin film wafer and substrate layer are made of different materials, the heat treatment of the bonded structure of the non-homogeneous thin film wafer and substrate layer can cause the thin film wafer bonded to the substrate layer to warp due to the different thermal expansion coefficients of the thin film wafer and substrate layer during annealing and separation. When the critical condition for separation of the thin film wafer and substrate layer is reached, the residual material layer peels off from the substrate layer, forming a warped thin film layer. The warped thin film layer may then break during the process of returning to a flat state. Summary of the Invention

[0005] The present invention provides a method for secondary ion implantation of thin film wafers, a composite thin film, and an electronic component to solve the problem of warping of the thin film layer when the residual layer peels off from the substrate layer when the critical condition for separation of the thin film wafer from the substrate is reached. The warped thin film layer may break during the process of returning to a flat state.

[0006] In a first aspect, an embodiment of the present application provides a method for secondary ion implantation into a thin film wafer, comprising:

[0007] Prepare thin film wafers and non-homogeneous substrate wafers;

[0008] Performing two ion implantation processes on the thin film wafer, wherein the difference between the depth of the first ion implantation and the depth of the second ion implantation is 20 nm to 200 nm, to obtain a thin film wafer implantation sheet having a four-layer structure including a residual layer, a first implantation layer, a second implantation layer and a thin film layer;

[0009] Bonding the thin film wafer implantation sheet and the heterogeneous substrate wafer to obtain a bonded body;

[0010] performing a heat treatment on the bonded body to form a first bubble layer in the first injection layer and a second bubble layer in the second injection layer, wherein the first bubble layer and the second bubble layer are fused to form a separated bubble layer;

[0011] The residual layer is peeled off at the bubble separation layer, so that the residual layer is separated from the film layer to obtain a composite film.

[0012] Furthermore, the temperature range of the heat treatment process is 150°C-210°C.

[0013] Furthermore, the ions of the first ion implantation and the second ion implantation are the same, and the implanted ions are helium ions, hydrogen ions, nitrogen ions, oxygen ions or argon ions.

[0014] Furthermore, the ion implantation dose parameters of the first ion implantation and the second ion implantation are both 1×10 16 ions / cm 2 Up to 4x10 16 ions / cm 2 .

[0015] Furthermore, bonding is performed on the thin film wafer implantation sheet, comprising:

[0016] forming a silicon oxide layer on one side of a non-homogeneous substrate wafer to obtain a first silicon oxide layer;

[0017] The thin film wafer implantation sheet is completely contacted with the first silicon oxide layer to obtain the bonded body.

[0018] Furthermore, forming a silicon oxide layer on one side of the non-homogeneous substrate wafer includes:

[0019] A capture layer is obtained by depositing polysilicon or amorphous silicon on one side of a non-homogeneous substrate wafer by a deposition method, or by generating corrosion damage by an etching method, or by generating injection damage by an injection method;

[0020] A silicon oxide layer is formed on the capture layer to obtain the first silicon oxide layer.

[0021] Furthermore, the non-homogeneous substrate wafer is a silicon wafer, a silicon carbide wafer or a silicon nitride wafer.

[0022] Furthermore, the thin film wafer is a lithium niobate thin film wafer or a lithium tantalate thin film wafer.

[0023] In a second aspect, the examples of the present application provide a composite film, which is prepared by the method described in any one of the first aspects.

[0024] In a third aspect, the embodiments of the present application provide an electronic component, which includes the composite film described in the second aspect.

[0025] An embodiment of the present application provides a method for secondary ion implantation of a thin film wafer, a composite thin film and an electronic component, wherein the method comprises: preparing a thin film wafer and a non-homogeneous substrate wafer; performing two ion implantation treatments on the thin film wafer, wherein the difference between the depth of the first ion implantation and the depth of the second ion implantation is 20nm-200nm, to obtain a thin film wafer implantation sheet having a four-layer structure comprising a residual layer, a first implantation layer, a second implantation layer and a thin film layer; bonding the thin film wafer implantation sheet and the non-homogeneous substrate wafer to obtain a bonded body; performing heat treatment on the bonded body to form a first bubble layer in the first implantation layer and a second bubble layer in the second implantation layer, wherein the first bubble layer and the second bubble layer are fused into a separation bubble layer; peeling off the residual layer at the separation bubble layer to separate the residual layer from the thin film layer to obtain a composite thin film.

[0026] The present invention adopts a two-time ion implantation method for a thin film wafer, controls the difference between the depth of the first ion implantation and the depth of the second ion implantation to be 20nm-200nm, and the depth is controlled by the implantation energy. During annealing and stripping, bubble layers are simultaneously formed at the first ion implantation layer and the second ion implantation layer, and the two bubble layers are fused into a separation bubble layer. Finally, stripping is achieved at the separation bubble layer. Since the separation bubble layer is formed by the fusion of the two bubble layers, the separation bubble layer is increased in number and thickness compared with the original, making separation easier. The temperature does not need to be too high to achieve the purpose of separation. The separation temperature of the present invention can be reduced from 220°C to 320°C in the prior art to 150°C to 210°C.

[0027] The separation temperature of the present invention is reduced, so there will be no problem of film layer cracking caused by the difference in thermal expansion coefficient between the film wafer and the non-homogeneous substrate wafer, thereby improving the yield rate of the finished film product. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 A schematic flow chart of a method for secondary ion implantation into a thin film wafer according to an embodiment of the present application;

[0030] Figure 2 A schematic diagram of forming a composite thin film in a method for secondary ion implantation into a thin film wafer according to an embodiment of the present application;

[0031] Figure 3 A schematic diagram of forming a separation bubble layer in a secondary ion implantation thin film wafer method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] To solve the problem that if the thin film wafer and the substrate layer are made of two different materials, when the bonded body of the non-homogeneous thin film wafer and the substrate layer is heat-treated, the thin film wafer bonded to the substrate layer will warp due to the different thermal expansion coefficients of the thin film wafer and the substrate layer during annealing and separation. When the critical condition for separation of the thin film wafer and the substrate layer is reached, the residual layer peels off from the substrate layer, thereby forming a warped thin film layer. The warped thin film layer may break in the process of returning to a flat state. Therefore, to solve the above problems, an embodiment of the present application provides a method for secondary ion implantation of a thin film wafer.

[0034] See also Figure 1 , is a schematic flow chart of a method for secondary ion implantation into a thin film wafer provided in this application;

[0035] As can be seen from the figure, the present application provides a method for secondary ion implantation into a thin film wafer, the method comprising:

[0036] S1: Prepare thin film wafer and non-homogeneous substrate wafer.

[0037] Prepare a thin film wafer, which can be a lithium niobate thin film wafer or a lithium tantalate thin film wafer. Prepare a non-homogeneous substrate wafer, which can be a silicon wafer, a silicon carbide wafer, or a silicon nitride wafer.

[0038] S2: performing two ion implantation processes on the thin film wafer.

[0039] The difference between the depth of the first ion implantation and the depth of the second ion implantation is 20nm-200nm, and a thin film wafer implantation piece including a residual layer, a first implantation layer, a second implantation layer and a thin film layer is obtained.

[0040] This step mainly uses the first ion implantation process. The ions implanted can be helium ions, hydrogen ions, nitrogen ions, oxygen ions or argon ions. For example, helium ions. When implanting helium ions, the first ion implantation depth can be selected at any value. The energy of the implantation depends on the implantation depth in nanometers. The implantation dose can be 1x10 16 ions / cm 2 Up to 4x10 16 ions / cm 2 .

[0041] For example, helium ions (He + ) is implanted into the lithium niobate wafer. The first helium ion implantation depth can be 780nm, the helium ion implantation energy can be 225keV, and the implantation dose can be 2x10 16 ions / cm 2 , forming a lithium niobate thin film wafer having a separation layer, a first injection layer and a thin film layer.

[0042] After the first ion implantation, the second ion implantation is performed. To form a separation bubble layer at the same temperature, the ions implanted twice can be the same ion. To make the separation bubble layer continuous, the depth of the second ion implantation must be within the difference range from the first ion implantation, which can usually be between 20nm and 200nm. For example, for the second ion implantation of lithium niobate wafers, the implantation depth can be 840nm, the implantation energy is 250keV, and the implantation dose is 2x10 16 ions / cm 2 After the second ion implantation, the lithium niobate wafer is sequentially divided from the implantation surface into thin film wafer implantation pieces having a four-layer structure of a separation layer, a first implantation layer, a second implantation layer and a thin film layer.

[0043] In an embodiment of the present application, the thickness of the thin film layer can be adjusted by adjusting the depth difference between the two ion injections. Specifically, the greater the depth difference between the two ion injections, the thicker the separation layer thickness of the prepared thin film layer; conversely, the smaller the depth difference between the two ion injections, the thinner the separation layer thickness of the prepared thin film layer.

[0044] S3: Bonding the thin film wafer implantation sheet and the heterogeneous substrate wafer to obtain a bonded body.

[0045] In this step, a bonded body can be obtained by directly bonding the thin film wafer injection piece to the non-homogeneous substrate wafer, or by first forming a silicon oxide layer on one side of the non-homogeneous substrate wafer to obtain a first silicon oxide layer; and then completely contacting the thin film wafer injection piece with the first silicon oxide layer to obtain the bonded body. The non-homogeneous substrate wafer prepared can be a silicon wafer, a silicon carbide wafer, or a silicon nitride wafer. The method for preparing the silicon dioxide layer is not particularly limited. The silicon dioxide layer can be prepared by LPCVD (Low Pressure Chemical Vapor Deposition) or PECVD (Plasma Enhanced Chemical Vapor Deposition). Any of the existing methods can be used to form a silicon oxide layer on one side of the substrate wafer to obtain the first silicon oxide layer.

[0046] Alternatively, the capture layer can be formed first and then the silicon oxide layer. Directly forming a silicon oxide layer on one side of a non-homogeneous substrate wafer generates carriers, so forming the capture layer first is intended to store the carriers within the capture layer. There are several methods for forming the capture layer, and any one of these methods can be selected. Specifically, the capture layer can be formed by depositing polycrystalline silicon or amorphous silicon using a deposition method, or by generating an etching damage layer using an etching method; or by generating an injection damage layer using an implantation method; and then forming a silicon oxide layer on the capture layer to form the first silicon oxide layer.

[0047] This step is to directly bond the thin film wafer implanted in step S2 to the non-homogeneous substrate wafer in step S3 to obtain a bonded body. This application does not specifically limit the bonding method, and any bonding method in the prior art can be used.

[0048] S4: performing heat treatment on the bonded body to form a first bubble layer in the first injection layer and a second bubble layer in the second injection layer, wherein the first bubble layer and the second bubble layer are fused to form a separated bubble layer.

[0049] When ion implantation is performed with the same energy, a certain implantation width will be formed in the ion implantation layer due to the incident deviation of the ion implantation. The center position of the ion implantation layer is the highest point of the ion implantation dose. The existing technology adopts a single ion implantation. When separation is performed through heat treatment after bonding, a separation bubble layer is formed at the highest point of the ion dose in the ion implantation layer for separation. This separation requires a higher separation temperature, and after separation, there will be residual material in the separation residual layer on the surface. The high separation temperature plus the difference in thermal expansion coefficient will cause the film to break.

[0050] like Figure 3As shown, the bond body is subjected to heat treatment, and the temperature range of the heat treatment is controlled to be 150°C-210°C. The present invention adopts two ion implantations, and there are ion dose peaks on both the first implantation layer and the second implantation layer, and the distance difference between the ion dose peaks of the first implantation layer and the second implantation layer is controlled to be 20-200nm. This distance is controlled by the implantation energy, and the implantation doses of the first implantation layer and the second implantation layer are: 1×10 16 ions / cm 2 -4×10 16 ions / cm 2 The doses of the two ion implantations can be the same or different. After the implanted wafer is bonded to a non-homogeneous substrate, during annealing separation, the first separation bubble layer and the second separation bubble layer are simultaneously formed at the highest points of the ion dose of the first implantation layer and the second implantation layer. Since the distance between the highest points of the ion dose of the two layers is close (20-200nm), the two layers of separation bubble layers will be connected into one piece, and finally form a separation bubble layer. If only one layer of ions is implanted, a higher temperature is required to form a separation bubble layer, and the higher the temperature, the higher the possibility of the thin film layer breaking. Therefore, through two ion implantations, the temperature required to form the separation bubble layer can be reduced, thereby effectively reducing the possibility of the thin film wafer breaking.

[0051] S5: peeling off the residual layer at the separation bubble layer, so that the residual layer is separated from the film layer to obtain a composite film.

[0052] The remaining material layer at the separation bubble layer is peeled off, so that separation becomes easier and the temperature does not need to be too high to achieve the purpose of separation. In this way, the film wafer and the substrate wafer will not break due to the difference in thermal expansion coefficient caused by excessively high temperature.

[0053] like Figure 2 , which is a schematic diagram of the formation of a composite film according to an embodiment of the present application, and finally the film layer of the composite film is further subjected to edge grinding, polishing and cleaning processes.

[0054] Based on the above disclosed method, an embodiment of the present application further discloses a composite thin film, which is prepared by the secondary ion implantation thin film wafer method as described in any one of the above items.

[0055] Based on the composite film disclosed above, an embodiment of the present application further discloses an electronic component, which includes the composite film described above.

[0056] To further illustrate the technical solutions in this application, the embodiments of this application further disclose the following specific embodiments.

[0057] Example 1

[0058] 1) Prepare a 500 μm silicon wafer and a 200 μm lithium niobate wafer, fix the silicon wafer or lithium niobate on a porous ceramic chuck of a polishing device, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on both wafers to obtain a clean surface.

[0059] 2) Perform the first ion implantation of He into the lithium niobate wafer after step 1 + The first ion implantation depth is 780nm, the implantation energy is 225keV, and the implantation dose is 2×10 16 ions / cm 2 , and then a second ion implantation of He + The second ion implantation depth is 840nm, the implantation energy is 250keV, and the implantation dose is 2×10 16 ions / cm 2 , so that the lithium niobate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0060] 3) The thin film layer of the thin film wafer implantation sheet is brought into contact with the silicon wafer, and they are bonded using a direct bonding method to obtain a bonded body.

[0061] 4) The bonded body is placed in an annealing furnace and kept warm at 160°C for 18 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0062] 5) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 600 nm, and then RCA cleaning is performed to obtain a clean surface.

[0063] Example 2

[0064] 1) Prepare a 500 μm silicon wafer and a 200 μm lithium niobate wafer, fix the silicon wafer or lithium niobate on a porous ceramic chuck of a polishing device, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on both wafers to obtain a clean surface.

[0065] 2) Perform the first ion implantation of He into the lithium niobate wafer after step 1 + The first ion implantation depth is 780nm, the implantation energy is 225keV, and the implantation dose is 2×10 16 ions / cm2 , and then a second ion implantation of He + The second ion implantation depth is 840nm, the implantation energy is 250keV, and the implantation dose is 2×10 16 ions / cm 2 , so that the lithium niobate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0066] 3) A silicon dioxide layer was formed on the cleaned silicon wafer using the LPCVD method, and then chemical mechanical polishing was performed to a thickness of 100 nm to obtain a smooth surface, and RCA cleaning was performed to obtain a clean surface.

[0067] 4) The thin film layer of the thin film wafer implantation sheet is brought into contact with the silicon dioxide layer, and they are bonded using a direct bonding method to obtain a bonded body.

[0068] 5) The bonded body is placed in an annealing furnace and kept warm at 160°C for 18 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0069] 6) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 600 nm, and then RCA cleaning is performed to obtain a clean surface.

[0070] Example 3

[0071] 1) A 500μm silicon wafer and a 250μm lithium tantalate wafer are fixed on the porous ceramic chuck of the polishing equipment. Chemical mechanical polishing is performed to obtain a smooth surface. Then, semiconductor RCA cleaning is performed on both wafers to obtain a clean surface.

[0072] 2) The lithium niobate wafer processed in step 1 is implanted with hydrogen ions using the lift-off ion implantation method. The depth of the first ion implantation is 800 nm, the implantation energy is 239 kev, and the implantation dose is 3×10 16 ions / cm 2 Then the second ion implantation of hydrogen ions was carried out. The depth of the second ion implantation was 832nm, the implantation energy was 245keV, and the implantation dose was 3×10 16 ions / cm 2 , so that the lithium tantalate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0073] 3) Polysilicon is produced on the cleaned silicon nitride wafer using the PECVD method with a thickness of 1 μm, which is the capture layer.

[0074] 4) A silicon dioxide layer was formed on the capture layer by thermal oxidation, and then chemical mechanical polishing was performed to obtain a smooth surface with a thickness of 1 μm, and RCA cleaning was performed to obtain a clean surface.

[0075] 5) The thin film wafer implantation sheet is brought into contact with the silicon dioxide layer and bonded using a direct bonding method to obtain a bonded body.

[0076] 6) The bonded body is placed in an annealing furnace and kept warm at 200°C for 13 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0077] 7) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 600 nm, and then RCA cleaning is performed to obtain a clean surface.

[0078] Example 4

[0079] 1) A 500μm silicon carbide wafer and a 500μm lithium tantalate wafer were fixed on the porous ceramic chuck of the polishing equipment and chemically mechanically polished to obtain a smooth surface. Then, both wafers were cleaned by semiconductor RCA to obtain a clean surface.

[0080] 2) Nitrogen ions were implanted into the lithium tantalate wafer after the treatment in step 1 by using the stripping ion implantation method. The depth of the first ion implantation was 650 nm, the implantation energy was 180 kev, and the implantation dose was 4 × 10 16 ions / cm 2 Then, the second ion implantation of nitrogen ions was performed. The depth of the second ion implantation was 850nm, the implantation energy was 250keV, and the implantation dose was 4×10 16 ions / cm 2 , so that the lithium niobate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0081] 3) Amorphous silicon with a thickness of 10 μm is deposited on the cleaned silicon carbide wafer using a PVD (Physical Vapor Deposition) method as a capture layer.

[0082] 4) A silicon dioxide layer was formed on the capture layer by PVD, and then chemical mechanical polishing was performed to obtain a smooth surface with a thickness of 10 μm, and RCA cleaning was performed to obtain a clean surface.

[0083] 5) The thin film wafer implantation sheet is brought into contact with the silicon dioxide layer and bonded using a direct bonding method to obtain a bonded body.

[0084] 6) The bonded body is placed in an annealing furnace and kept warm at 150°C for 20 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0085] 7) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 800 nm, and then RCA cleaning is performed to obtain a clean surface.

[0086] Example 5

[0087] 1) Prepare a 500 μm silicon nitride wafer and a 250 μm lithium niobate wafer, fix the silicon nitride wafer or lithium niobate wafer on a porous ceramic chuck of a polishing device, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on both wafers to obtain a clean surface.

[0088] 2) The lithium niobate wafer processed in step 1 is implanted with oxygen ions by using the stripping ion implantation method. The depth of the first ion implantation is 440 nm, the implantation energy is 100 kev, and the implantation dose is 1×10 16 ions / cm 2 Then, the second ion implantation of oxygen ions was performed. The depth of the second ion implantation was 460nm, the implantation energy was 110keV, and the implantation dose was 1×10 16 ions / cm 2 , so that the lithium niobate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0089] 3) The damaged layer is wet-etched on the cleaned silicon nitride wafer. The damaged layer is the capture layer and has a thickness of 2 μm.

[0090] 4) A silicon dioxide layer was formed on the capture layer by thermal oxidation, and then chemical mechanical polishing was performed to obtain a smooth surface with a thickness of 1 μm, and RCA cleaning was performed to obtain a clean surface.

[0091] 5) The thin film wafer implantation sheet is brought into contact with the silicon dioxide layer and bonded using a direct bonding method to obtain a bonded body.

[0092] 6) The bonded body is placed in an annealing furnace and kept warm at 180°C for 14 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0093] 7) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 600 nm, and then RCA cleaning is performed to obtain a clean surface.

[0094] Example 6

[0095] 1) Prepare a 500μm silicon wafer and a 400μm lithium tantalate wafer, fix the silicon wafer or lithium tantalate wafer on the porous ceramic chuck of the polishing equipment, perform chemical mechanical polishing to obtain a smooth surface, and then perform semiconductor RCA cleaning on both wafers to obtain a clean surface.

[0096] 2) The lithium niobate wafer processed in step 1 is implanted with argon ions by using the stripping ion implantation method. The depth of the first ion implantation is 280 nm, the implantation energy is 550 kev, and the implantation dose is 2×10 16 ions / cm 2 Then, the second ion implantation of argon ions was performed. The depth of the second ion implantation was 300 nm, the implantation energy was 60 keV, and the implantation dose was 2 × 10 16 ions / cm 2 , so that the lithium niobate wafer is divided into a separation layer, a first injection layer, a second injection layer and a thin film layer in sequence starting from the injection surface, to obtain a thin film wafer injection piece.

[0097] 3) Argon ions are implanted into the cleaned silicon wafer using an ion implantation method to form a damaged silicon layer, i.e., a capture layer, with a thickness of 1 μm.

[0098] 4) A silicon dioxide layer with a thickness of 5 μm was formed on the capture layer by PECVD, followed by chemical mechanical polishing to obtain a smooth surface, and RCA cleaning to obtain a clean surface.

[0099] 5) The thin film wafer implantation sheet is brought into contact with the silicon dioxide layer and bonded using a direct bonding method to obtain a bonded body.

[0100] 6) The bonded body is placed in an annealing furnace and kept warm at 210°C for 12 hours. A first separation bubble layer is formed at the highest point of the ion dose of the first injection layer, and a second separation bubble layer is formed at the highest point of the ion dose of the second injection layer. The first bubble separation layer and the second bubble separation layer are connected to form a separation bubble layer. The residual layer is peeled off at the separation bubble layer, and the remaining film layer is bonded to the substrate wafer to obtain a composite film.

[0101] 7) The composite film is fixed on a porous ceramic chuck of a polishing device, and the film layer is subjected to chemical mechanical polishing to 600 nm, and then RCA cleaning is performed to obtain a clean surface.

[0102] The above embodiments are intended only to illustrate the method for secondary ion implantation of thin film wafers and are not intended to limit the method. The various steps or parameters in the aforementioned embodiments may also be combined in other ways and will not be described here. The technical solutions formed by combining the aforementioned steps or parameters are also within the scope of protection of this application.

[0103] The present invention provides a method for secondary ion implantation of a thin film wafer, a composite thin film, and an electronic component, wherein the method comprises: preparing a thin film wafer and a non-homogeneous substrate wafer; performing two ion implantation processes on the thin film wafer, wherein the difference between the depth of the first ion implantation and the depth of the second ion implantation is 20nm-200nm, thereby obtaining a thin film wafer implantation sheet having a four-layer structure including a residual layer, a first implantation layer, a second implantation layer, and a thin film layer; bonding the thin film wafer implantation sheet to the non-homogeneous substrate wafer to obtain a bonded body; performing a heat treatment on the bonded body to form a first bubble layer in the first implantation layer and a second bubble layer in the second implantation layer, wherein the first bubble layer and the second bubble layer fuse to form a separation bubble layer; and peeling off the residual layer at the separation bubble layer to separate the residual layer from the thin film layer to obtain a composite thin film. The present invention utilizes a method of reducing the separation temperature and secondary ion implantation to prevent a large difference in thermal expansion coefficient between the thin film wafer and the substrate wafer, thereby preventing the problem of the thin film layer bursting, thereby improving the yield rate of the finished thin film product.

[0104] The technical solution of this application makes it easier to separate the thin film wafer and the substrate wafer by lowering the separation temperature and the secondary ion implantation method. Even substrate wafers made of different materials can be easily separated with little residue. The prior art will produce raised residual material in the residual layer after separation at the separation layer, while the present invention significantly reduces the residual raised material and makes polishing and grinding easier.

[0105] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the appended claims.

[0106] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for secondary ion implantation into thin film wafers, characterized in that: The method comprises: Prepare thin film wafers and non-homogeneous substrate wafers; Performing two ion implantation processes on the thin film wafer, wherein the difference between the depth of the first ion implantation and the depth of the second ion implantation is 20 nm to 200 nm, the ions implanted in the first ion implantation and the second ion implantation are the same, and the implanted ions are helium ions, hydrogen ions, nitrogen ions, or argon ions, to obtain a thin film wafer having a four-layer structure including a residual layer, a first implantation layer, a second implantation layer, and a thin film layer; Bonding the thin film wafer implantation sheet and the heterogeneous substrate wafer to obtain a bonded body; performing a heat treatment on the bonded body at a temperature range of 150° C. to 210° C., forming a first bubble layer in the first injection layer, forming a second bubble layer in the second injection layer, and fusing the first bubble layer and the second bubble layer to form a separated bubble layer; The residual layer is peeled off at the bubble separation layer, so that the residual layer is separated from the film layer to obtain a composite film.

2. The method for secondary ion implantation into thin film wafer according to claim 1, characterized in that: The ion implantation dose parameters of the first ion implantation and the second ion implantation are both 1×10 16 ions / cm 2 Up to 4x10 16 ions / cm 2 .

3. The method for secondary ion implantation into thin film wafer according to claim 1, characterized in that: Bonding the thin film wafer implant sheet to the heterogeneous substrate wafer includes: forming a silicon oxide layer on one side of a non-homogeneous substrate wafer to obtain a first silicon oxide layer; The thin film wafer implantation sheet is bonded to the first silicon oxide layer to obtain the bonded body.

4. The method for secondary ion implantation into thin film wafer according to claim 3, characterized in that: Producing a silicon oxide layer on one side of the non-homogeneous substrate wafer includes: A capture layer is obtained by depositing polysilicon or amorphous silicon on one side of a non-homogeneous substrate wafer by a deposition method, or by generating corrosion damage by an etching method, or by generating injection damage by an injection method; A silicon oxide layer is formed on the capture layer to obtain the first silicon oxide layer.

5. The method for secondary ion implantation into thin film wafer according to claim 1, characterized in that: The non-homogeneous substrate wafer is a silicon wafer, a silicon carbide wafer or a silicon nitride wafer.

6. The method for secondary ion implantation into thin film wafer according to claim 1, characterized in that: The thin film wafer is a lithium niobate thin film wafer or a lithium tantalate thin film wafer.

7. A composite film, characterized in that The composite film is prepared by the secondary ion implantation thin film wafer method according to any one of claims 1 to 6.

8. An electronic component, characterized in that: The electronic component comprises the composite film according to claim 7.

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