Wafer-level aluminum molybdate film, preparation method thereof, packaging method and semiconductor device

Abstract

The application belongs to the field of semiconductors and relates to a wafer-level aluminum molybdate film, which comprises a wafer substrate and a film arranged on at least one side of the wafer substrate, a plurality of protrusions are formed on the surface of the wafer substrate on the side facing the film, the wafer substrate is a sapphire substrate, and the film comprises aluminum molybdate. The application also relates to a method for preparing the wafer-level aluminum molybdate film, a packaging method and a semiconductor device. The wafer-level aluminum molybdate film of the application is uniform in thickness, good in continuity, flat in surface, has good semiconductor performance and can promote the application in semiconductor devices.

Description

Technical Field

[0001] This application belongs to the field of semiconductors, specifically relating to a wafer-level aluminum molybdate thin film, a method for preparing the wafer-level aluminum molybdate thin film, a packaging method, and a semiconductor device. Background Technology

[0002] Aluminum molybdate is a high-performance, high-dielectric ceramic oxide with negative thermal expansion characteristics, good dielectric properties and catalytic activity, and has broad application prospects in microelectronics, optoelectronic devices and other fields.

[0003] Existing methods for preparing aluminum molybdate on common substrates, such as ceramic substrates, include powder sintering and sol-gel methods. Traditional methods primarily focus on powder sintering, which involves mixing alumina and molybdenum oxide powders and then calcining at high temperatures for an extended period. However, the products obtained by this method are mostly powdery or discontinuous nanosheets with inhomogeneous morphology. While the sol-gel method can control the product morphology to some extent, it cannot obtain continuous and uniform films. Furthermore, the sol-gel process is complex and unsuitable for large-scale production. Therefore, existing technologies struggle to prepare continuous and uniform aluminum molybdate films on common substrates.

[0004] Sapphire substrates have single-crystal characteristics, with strong surface chemical inertness and low surface energy, making it difficult for thin films to adhere. This makes it more difficult to achieve continuous and uniform growth of aluminum molybdate thin films on sapphire substrates, which severely limits the integrated application of wafer-level thin films in actual devices and also hinders compatibility with semiconductor processes.

[0005] Therefore, there is an urgent need for a technology to prepare continuous and uniform aluminum molybdate thin films on sapphire substrates. Summary of the Invention

[0006] One objective of this application is to provide a wafer-level aluminum molybdate thin film with uniform thickness, good continuity, and excellent semiconductor properties. Another objective of this application is to provide a method for preparing the wafer-level aluminum molybdate thin film, a packaging method, and a semiconductor device.

[0007] To achieve the above objectives, a first aspect of this application provides a wafer-level aluminum molybdate thin film, comprising a wafer substrate and a thin film disposed on at least one side of the wafer substrate, wherein a plurality of protrusions are formed on the surface of the wafer substrate facing the thin film, the wafer substrate being a sapphire substrate, and the thin film comprising aluminum molybdate.

[0008] Therefore, the confined space formed by multiple protrusions on the wafer substrate surface can provide multiple micro-reaction chambers for the thin film preparation reaction. The mass transfer in the reaction within these micro-reaction chambers is uniform, thus enabling the uniform preparation of the thin film across the entire substrate surface. Furthermore, the multiple protrusions can serve as nucleation sites to promote the reaction. At the same time, the multiple protrusions can also effectively regulate the local stress during the thin film reaction process, reducing the formation of defects such as film cracking. This results in a more continuous, uniform, and smooth aluminum molybdate thin film with excellent semiconductor properties, promoting its practical application in semiconductor devices.

[0009] In any embodiment of the first aspect of this application, the height of each of the plurality of protrusions is independently greater than 0 and less than or equal to 1.5 µm.

[0010] In any embodiment of the first aspect of this application, the height difference between the plurality of protrusions is <1.5 µm.

[0011] This application, by defining the height of the protrusion and the height difference, can further homogenize the confined space in the height direction, thereby improving the uniformity of the reaction.

[0012] In any embodiment of the first aspect of this application, the spacing between adjacent protrusions is 0.5 µm-5 µm, for example 1 µm, 2 µm, 3 µm, or 4 µm.

[0013] By defining the spacing of the protrusions, this application can further homogenize the confined space along the substrate surface, thereby further improving the uniformity of reaction mass transfer.

[0014] In any embodiment of the first aspect of this application, the shapes of the plurality of protrusions projected onto the surface of the wafer substrate are each independently selected from one or more of circles, triangles, and squares.

[0015] In any embodiment of the first aspect of this application, the area of ​​each of the plurality of protrusions projected onto the surface of the wafer substrate is independently 0.2 µm. 2 -20 µm 2 For example, 1 µm 2 2 µm 2 3µm 2 4µm 2 5µm 2 6µm 2 6.1575µm 2 6.5µm 2 7µm 2 8µm 2 9µm 2 10µm 2 11µm 2 12µm2 15µm 2 16µm 2 18µm 2 20µm 2 .

[0016] In any embodiment of the first aspect of this application, the difference in the area of ​​the projections of the plurality of protrusions onto the surface of the wafer substrate is ≤5 µm. 2 For example, ≤4 µm 2 ≤3 µm 2 ≤2µm 2 ≤1µm 2 ≤0.5µm 2 .

[0017] This application uses multiple protrusions to form a confined space on the substrate surface as a micro-reaction chamber. By limiting the area and area difference of the protrusion projections, the volume uniformity of the confined space can be further improved, thereby improving the mass transfer uniformity of the reaction.

[0018] In any embodiment of the first aspect of this application, the tips of the plurality of protrusions are each independently a sharp point or a plane.

[0019] In any embodiment of the first aspect of this application, the plurality of protrusions are conical.

[0020] In any embodiment of the first aspect of this application, the thickness of the thin film is 1500 nm - 2500 nm, for example, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, 2000 nm, 2100 nm, 2200 nm, 2300 nm, or 2400 nm. This thickness range improves the film's coverage, ensuring good semiconductor performance; furthermore, increased thickness may lead to cracking of the film, affecting its semiconductor performance, and the aforementioned thickness range reduces this impact.

[0021] In any embodiment of the first aspect of this application, the thickness uniformity deviation of the film is <5%, for example, 0.1%, 1%, 2%, 3%, 4%, or 4.5%.

[0022] In any embodiment of the first aspect of this application, the porosity of the thin film is ≤1 / 100, for example, 0%, 1 / 100, 1 / 1000, or 1 / 10000. The porosity of the thin film in this application within the above range ensures the film's coverage, which is beneficial for the performance of semiconductors.

[0023] In any embodiment of the first aspect of this application, the area of ​​the wafer substrate facing the thin film is used as a reference, and the area ratio of the thin film is ≥85%, for example 85%, 90%, 95%, 99%, 99.999%, 100%.

[0024] In any embodiment of the first aspect of this application, the X-ray diffraction pattern of the thin film includes a characteristic peak with a 2θ of 12°-13° (e.g., a characteristic peak with a 2θ of 12.85°), and the full width at half maximum (FWHM) of the characteristic peak is 0.01° - 0.5°, for example, 0.02°, 0.05°, 0.06°, 0.1°, 0.2°, 0.3°, 0.4°, or 0.5°. This peak is a characteristic peak of Al2(MoO4)3, indicating that the material of the thin film in this application is Al2(MoO4)3.

[0025] In any embodiment of the first aspect of this application, a Cu Kα radiation source is used for X-ray diffraction pattern testing.

[0026] In any embodiment of the first aspect of this application, the root mean square roughness of the thin film surface is ≤20 nm, for example, 0.5 nm, 1 nm, 2 nm, 3 nm, 5 nm, 7 nm, 9 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, or 20 nm. The low surface roughness of the thin film in this application is beneficial for improving the semiconductor performance and device stability of the thin film.

[0027] In any embodiment of the first aspect of this application, the content deviation of molybdenum, aluminum, and oxygen in any two regions of the thin film is independently ≤5%, for example, 0%, 1%, 2%, 3%, 4%, and 4.5%. This indicates that this application forms a uniform and continuous aluminum molybdate thin film on the surface of a wafer substrate.

[0028] In any embodiment of the first aspect of this application, the crystal orientation of the sapphire substrate is selected from any one of (0001), (11-20), (10-10), and (1-102).

[0029] In any embodiment of the first aspect of this application, the thickness of the wafer substrate is 0.3 mm - 1 mm, for example 0.3 mm, 0.5 mm, or 1 mm.

[0030] In any embodiment of the first aspect of this application, the diameter of the wafer substrate is 5 cm to 31 cm, for example, 5 cm, 5.08 cm, 6 cm, 8 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, or 31 cm.

[0031] A second aspect of this application provides a method for preparing wafer-level aluminum molybdate thin films, comprising: A wafer substrate and a metal foil are alternately arranged to form a stacked structure; before the alternation, a plurality of protrusions are formed on the surface of the wafer substrate facing the metal foil; wherein the wafer substrate is a sapphire substrate and the metal foil includes molybdenum metal; A pressure greater than 0 and less than or equal to 0.05 MPa (optionally 0.01 MPa-0.05 MPa, such as 0.01 MPa, 0.02 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa) is applied to the opposite outer sides of the stacked structure, and the pressurized state is maintained. The stacked structure is then sintered in an oxygen-containing atmosphere (e.g., air) at 700°C-750°C (e.g., 700°C, 710°C, 720°C, 740°C, 750°C) for 1-8 hours (e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours) for 1-8 hours to obtain a wafer-level aluminum molybdate film. The wafer-level aluminum molybdate film includes a wafer substrate and a film disposed on at least one side of the wafer substrate, the film comprising aluminum molybdate.

[0032] Therefore, this application forms a stacked structure between a wafer substrate and a metal foil. In this stacked structure, under pressure, multiple protrusions on the surface of the wafer substrate and the metal foil form confined micro-reaction chambers. As the sintering process proceeds, the molybdenum metal foil gradually transforms into molybdenum oxide at high temperature in an oxygen-containing atmosphere. The molybdenum oxide vaporizes to form gaseous raw materials, which are uniformly mass-transferred and distributed on the surface of the wafer substrate in the micro-reaction chambers to react. Furthermore, the multiple protrusions provide nucleation sites for the reaction. At the same time, the multiple protrusions can effectively control the local stress during the film formation process and reduce the generation of film defects, thereby preparing a uniform, continuous and smooth aluminum molybdate film on the surface of the wafer substrate.

[0033] In this application, the arrangement of the multiple protrusions can be any feasible method, such as surface etching using focused ion beam (FIB).

[0034] In any embodiment of the second aspect of this application, the height of each of the plurality of protrusions is independently greater than 0 and less than or equal to 1.5 µm.

[0035] In any embodiment of the second aspect of this application, the height difference between the plurality of protrusions is ≤1.5 µm.

[0036] In any embodiment of the second aspect of this application, the spacing between adjacent protrusions is 0.5 µm-5 µm, for example 1 µm, 2 µm, 3 µm, or 4 µm.

[0037] In any embodiment of the second aspect of this application, the shapes of the plurality of protrusions projected onto the surface of the wafer substrate are each independently selected from one or more of circles, triangles, and squares.

[0038] In any embodiment of the second aspect of this application, the area of ​​each of the plurality of protrusions projected onto the surface of the wafer substrate is independently 0.2 µm. 2 -20 µm 2 For example, 1 µm 2 2 µm 2 3µm 2 4µm 2 5µm 2 6µm 2 6.1575µm 2 6.5µm 2 7µm 2 8µm 2 9µm 2 10µm 2 11µm 2 12µm 2 15µm 2 16µm 2 18µm 2 20µm 2 .

[0039] In any embodiment of the second aspect of this application, the difference in the area of ​​the projections of the plurality of protrusions onto the surface of the wafer substrate is ≤5 µm. 2 For example, ≤4 µm 2 ≤3 µm 2 ≤2µm 2 ≤1µm 2 ≤0.5µm 2 .

[0040] In any embodiment of the second aspect of this application, the tips of each of the plurality of protrusions are independently either sharp points or planes.

[0041] In any embodiment of the second aspect of this application, the plurality of protrusions are conical.

[0042] In any embodiment of the second aspect of this application, during the sintering process, the thickness of the laminated structure is set along the vertical or horizontal direction.

[0043] In any embodiment of the second aspect of this application, the number of the wafer substrate and the metal foil are each independently one or more. Optionally, there are two wafer substrates and one metal foil.

[0044] In any embodiment of the second aspect of this application, cooling is performed after sintering.

[0045] In any embodiment of the second aspect of this application, the thickness of the metal foil is 0.01 mm to 0.5 mm, for example 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0046] In any embodiment of the second aspect of this application, the crystal orientation of the sapphire substrate is selected from any one of (0001), (11-20), (10-10), and (1-102).

[0047] In any embodiment of the second aspect of this application, the thickness of the wafer substrate is 0.3 mm - 1 mm, for example 0.3 mm, 0.5 mm, or 1 mm.

[0048] In any embodiment of the second aspect of this application, the diameter of the wafer substrate is 5 cm to 31 cm, for example 5 cm, 5.08 cm, 6 cm, 8 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, or 31 cm.

[0049] A third aspect of this application provides an encapsulation method, including: A wafer-level aluminum molybdate film is provided, wherein the wafer-level aluminum molybdate film is the wafer-level aluminum molybdate film of the first aspect of this application or a wafer-level aluminum molybdate film prepared by the method of the second aspect of this application; A first conductive layer is disposed on the surface of the wafer-level aluminum molybdate thin film; A temporary carrier plate is disposed on the surface of the first conductive layer; The wafer substrate is peeled off from the wafer-level aluminum molybdate film; A second conductive layer is deposited on the exposed surface of the film after peeling to form a stacked structure; The stacked structure is transferred to the target substrate and permanently bonded. The temporary carrier board is then removed to obtain the packaged structure.

[0050] In the third aspect of this application, the material of the temporary carrier board is adjusted by those skilled in the art according to the specific packaging requirements. In some embodiments, the temporary carrier board is a silicon wafer or a glass sheet.

[0051] In the third aspect of this application, the material of the target substrate is adjusted by those skilled in the art according to the specific packaging requirements. In some embodiments, the target substrate is a target silicon substrate, such as a silicon wafer with an oxide layer on its surface.

[0052] In the third aspect of this application, the materials of the first conductive layer and the second conductive layer are adjusted by those skilled in the art according to specific packaging requirements. In some embodiments, the materials of the first conductive layer and the second conductive layer are selected from one or more of platinum, gold, titanium, aluminum or indium tin oxide.

[0053] In the third aspect of this application, the method of peeling the wafer substrate from the wafer-level aluminum molybdate film is selected by those skilled in the art according to the specific packaging requirements. In some embodiments, laser peeling is used.

[0054] In the third aspect of this application, permanent bonding is the bonding of the outer surface of the first conductive layer or the second conductive layer to the target substrate.

[0055] In the third aspect of this application, the method of removing the temporary carrier is selected by those skilled in the art according to the specific encapsulation requirements. In some embodiments, the temporary carrier is removed by heating, chemical dissolution or mechanical force.

[0056] In any embodiment of the third aspect of this application, the packaging uses a wafer-level aluminum molybdate film as a dielectric layer for three-dimensional integrated packaging.

[0057] A fourth aspect of this application provides a semiconductor device, comprising: The dielectric layer is a thin film in the wafer-level aluminum molybdate thin film of the first aspect of this application or a thin film in the wafer-level aluminum molybdate thin film prepared by the method of the second aspect of this application. The first conductive layer and the second conductive layer are respectively disposed on both sides of the dielectric layer; The target substrate is disposed on the side of the first conductive layer or the second conductive layer away from the dielectric layer.

[0058] In any embodiment of the fourth aspect of this application, the target substrate material is selected by those skilled in the art according to the specific device requirements. In some embodiments, the target substrate is a target silicon substrate, such as a silicon wafer with an oxide layer on its surface.

[0059] In any embodiment of the fourth aspect of this application, the materials of the first conductive layer and the second conductive layer are selected by those skilled in the art according to the specific device requirements. In some embodiments, the materials of the first conductive layer and the second conductive layer are selected from one or more of platinum, gold, titanium, aluminum or indium tin oxide.

[0060] In any embodiment of the fourth aspect of this application, the semiconductor device is selected from one or more of microelectronic devices, optoelectronic devices, integrated passive devices, and sensor devices.

[0061] In this application, microelectronic devices include, but are not limited to, MIM capacitors and gate dielectric layers. Optoelectronic devices include, but are not limited to, optical modulators and waveguide devices. Integrated passive devices (IPDs) include, but are not limited to, miniaturized, high-performance passive devices. Sensor devices include, but are not limited to, high-sensitivity sensors.

[0062] Unless otherwise specified, the terms used in this application are defined as follows: "Height of the protrusion" refers to the distance between the bottom and top of the protrusion.

[0063] The "split between protrusions" refers to the distance between the centers of two projections formed by two adjacent protrusions on the wafer substrate surface. For a centrally symmetric projection shape, the center is the center of symmetry; for a non-centrally symmetric projection shape, the center is the centroid, which can be calculated using coordinate integration.

[0064] "Thickness of the film" refers to the distance from the bottom of the protrusion to the outermost surface of the film.

[0065] This application achieves at least one of the following beneficial effects: 1. The wafer-level aluminum molybdate thin film of this application has uniform thickness, good continuity, high coverage on the substrate surface, smooth surface, good crystal quality, and good semiconductor performance.

[0066] 2. The method of this application prepares a thin film with uniform thickness, good continuity, high coverage and smooth surface by confining a small reaction chamber in a stacked structure formed by a wafer substrate and a metal foil.

[0067] 3. The method described in this application has simple operation and equipment requirements and low raw material costs, which is conducive to large-scale integrated application. Attached Figure Description

[0068] Figure 1 This is a photograph of the sapphire substrate of Embodiment 1 of this application.

[0069] Figure 2 This is an optical microscope image of the sapphire substrate in Embodiment 1 of this application.

[0070] Figure 3 This is an optical microscope image of the thin film surface in Example 1 of this application.

[0071] Figure 4 This is an SEM image of the cross-section along the thickness direction of the thin film after radial cutting in Example 1 of this application.

[0072] Figure 5 This is an optical microscope image of the thin film surface in Example 2 of this application.

[0073] Figure 6 This is an optical microscope image of the thin film surface in Example 3 of this application.

[0074] Figure 7 This is an optical microscope image of the thin film surface in Example 4 of this application.

[0075] Figure 8 This is an optical microscope image of the thin film surface in Example 5 of this application.

[0076] Figure 9 This is an optical microscope image of the thin film surface in Example 6 of this application.

[0077] Figure 10 This is an optical microscope image of the thin film surface in Comparative Example 1.

[0078] Figure 11 This is an optical microscope image of the thin film surface in Comparative Example 2.

[0079] Figure 12 The peak (002) is shown in the XRD pattern of the thin film in Example 1 of this application. Detailed Implementation

[0080] The embodiments of this application will be clearly and completely described below with reference to examples. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0081] Example 1 (1) A periodic array of conical bumps was etched on the surface of a wafer-level sapphire substrate [crystal orientation: (0001), diameter: 5.08 cm, thickness: 0.3 mm] using a focused ion beam (FIB) to obtain a patterned sapphire substrate. The height of the bumps was greater than 0 and less than or equal to 1.5 µm, the spacing of the bump array was 3 µm, and the area of ​​the bump projection on the substrate surface was 6.1575 µm. 2 Photos of sapphire substrates as shown below. Figure 1 As shown, the optical microscope image is as follows Figure 2 As shown.

[0082] (2) Using molybdenum foil (thickness of 0.05 mm) as the molybdenum source, the molybdenum foil is sandwiched between two patterned sapphire substrates, and the side of the sapphire substrate with the etched protrusion array faces the molybdenum foil, forming a sandwich structure of "substrate-molybdenum foil-substrate", and is fixed with molybdenum wire or quartz clamp to apply a pressure of 0.05 MPa.

[0083] (3) The sandwich structure was placed in a high-temperature tube furnace, maintaining its thickness vertically, and sintered at 700 °C for 2 hours in air. After sintering, it was cooled with the furnace, resulting in an Al2(MoO4)3 thin film on the sapphire substrate. The film thickness was 1700 nm. Optical microscope images of the film surface are shown below. Figure 3 As shown. SEM images of the cross-section along the thickness direction after radial cutting of the thin film are shown below. Figure 4 As shown.

[0084] Example 2 In step (2), the sandwich structure is fixed with molybdenum wire or quartz clamps to apply a pressure of 0.01 MPa; the sintering time in step (3) is 6 hours. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 5 As shown.

[0085] Example 3 In step (2), the sandwich structure is fixed using molybdenum wire or quartz clamps to apply a pressure of 0.03 MPa. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 6 As shown.

[0086] Example 4 In step (2), the thickness of the molybdenum foil is 0.5 mm. The remaining operations are the same as in Example 1. An optical microscope image of the film surface is shown below. Figure 7 As shown.

[0087] Example 5 In step (3), the sintering temperature is 750 °C, and the sintering time is 3 hours. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 8 As shown.

[0088] Example 6 In step (3), the sintering temperature is 700 °C and the sintering time is 8 hours. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 9 As shown.

[0089] Comparative Example 1 In step (2), no pressure is applied to the sandwich structure; in step (3), the sandwich structure is placed in a high-temperature tube furnace while maintaining its thickness in the horizontal direction. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 10 As shown.

[0090] Comparative Example 2 In step (3), the sintering temperature is 900 °C and the sintering time is 2 hours. The remaining operations are the same as in Example 1. Optical microscope images of the film surface are shown below. Figure 11 As shown.

[0091] Test Example 1: Parameter Testing Methods: The height of a protrusion refers to the distance between its bottom and top ends. The height of a protrusion is measured using a transmission electron microscope (TEM).

[0092] The protrusion spacing refers to the distance between the centers of two projections formed by two adjacent protrusions on the wafer substrate surface. The protrusion spacing is measured using a scanning electron microscope (SEM).

[0093] The area of ​​the protrusion projected onto the surface of the wafer substrate is measured by scanning electron microscopy (SEM) or atomic force microscopy (AFM).

[0094] The thickness of a thin film refers to the distance from the bottom of the protrusion to the outermost surface of the film. Thin film thickness testing method: The film is cut radially, and the cross-section in the thickness direction is observed using a scanning electron microscope (SEM). At least 5 measurement points are selected at equal intervals along the radial direction of the film, and the thickness value at each point is measured. The average value is the thickness of the film. The standard deviation of multiple thickness measurements is calculated, and the result divided by the average value is the thickness uniformity deviation.

[0095] The method for testing the porosity of thin films is as follows: The wafer-level aluminum molybdate thin film is imaged using a scanning electron microscope (SEM) to obtain a two-dimensional grayscale contrast image; the image is converted into a black-and-white binary image using ImageJ software based on the grayscale binarization; the porosity is calculated based on the area ratio of black dots; and the volume porosity is calculated based on the Dreiser principle, which is the porosity of the thin film.

[0096] Test method for thin film area ratio: The surface of the thin film is observed using a scanning electron microscope (SEM) with an accelerating voltage of 5~15 kV and a magnification of 5000~50000 times. The proportion of the thin film area in the area of ​​the wafer substrate facing the thin film is calculated.

[0097] Test method for elemental deviation in thin films: Take multiple (e.g., 5) equal-area regions on the surface of the thin film, analyze the content of molybdenum, aluminum and oxygen in each region using X-ray energy dispersive spectroscopy, and then calculate the content deviation of each element between any two regions.

[0098] Characteristic peak determination of the thin film: Phase analysis of the thin film was performed using an X-ray diffractometer with a Cu Kα radiation source (λ=1.5406 Å), a scanning range of 2θ=5°~80°, a scanning step size ≤0.02°, and a scanning speed ≤2° / min. Example 1: The (002) peak in the XRD pattern of the thin film is shown below. Figure 12 As shown in the figure, only the characteristic diffraction peak of Al2(MoO4)3 with 2θ=12.85° appears, with no other impurity peaks; the strongest characteristic diffraction peak is selected, and its full width at half maximum (FWHM) is 0.06°.

[0099] The surface roughness test method of the thin film is as follows: the surface morphology of the thin film is scanned by atomic force microscopy, with a scanning range of 5 µm × 5 µm to 20 µm × 20 µm, and the root mean square roughness (RMS) of the thin film surface is measured.

[0100] Test Example 2: Semiconductor Performance Testing Methods Q×f test method: The sample was polished into a standard thin sheet (5 cm in diameter, 0.3 mm thick), ensuring both sides were parallel and smooth. It was then cleaned and dried to remove impurities and moisture. The test temperature was 25.0 ± 1.0℃, and the humidity was (50 ± 2)%RH. A vector network analyzer was connected to the unloaded resonant cavity, and the unloaded resonant frequency f0 and unloaded quality factor Q0 of the cavity were recorded. The sample was then placed at the center of the resonant cavity where the electric field was strongest, and a TE filter using a dedicated thin-film perturbation method was selected. 011 The mode is used to sweep the frequency with a vector network analyzer, and the coupling is adjusted to make the forward transmission coefficient S 21 (f0) is between -30 dB and -50 dB. Record the resonant frequency f and quality factor Q after the sample is placed. The four parameters are calculated by the accompanying software to obtain the final value of Q×f, in GHz.

[0101] Breakdown field strength test method: The sample was polished to a thickness of 0.3 mm (multiple measurements were required to obtain the average value). Circular electrodes (Au material, upper electrode diameter 2.5 cm, lower electrode diameter 2.5 cm) were deposited on the upper and lower surfaces of the sample. The electrode edges were chamfered to prevent electric field concentration. The sample was immersed in insulating silicone oil for testing at a temperature of 25.0±1.0℃ and a humidity of (50±2)%RH. The sample was fixed between parallel plate electrodes, ensuring a tight fit between the electrodes and the sample without gaps. The voltage was increased uniformly at a rate of 100 V / s. The leakage current was monitored in real time. When the current suddenly increased sharply (current increase ≥1 mA), it was determined to be an electrical breakdown, and the high voltage was immediately shut off. The instantaneous breakdown voltage was recorded. The average value of 10-15 measurements for the same batch of samples was obtained. The average breakdown field strength was obtained by dividing the average instantaneous breakdown voltage by the thickness at the breakdown point of the sample, in units of MV / cm.

[0102] Room temperature leakage current test method: The sample was dusted and dried, then placed in an electromagnetic shielding box and tested in a dark environment at 25±1℃ and (50±2)%RH with no light. A fixed external bias voltage of 50V was set, and after applying the voltage, it was stabilized and left to stand for 80 seconds until the current stabilized. The steady-state weak current value was read as the room temperature leakage current I under the bias voltage. Multiple sets of leakage current curves (IV leakage curves) under the bias voltage can be generated. The surface leakage current density J is calculated according to the formula J=I / S, where S is the effective area of ​​the electrode (for example, the effective area of ​​a circular electrode is πR). 2(R represents the radius of the circular electrode). The specific operation is as follows: Apply a series of increasing bias voltages (e.g., 0V, 1V, 2V…100V) to the same sample, record the steady-state leakage current I, and obtain the IV relationship curve. To eliminate the influence of electrode area differences on leakage current evaluation, calculate the surface leakage current density J=I / S under each bias voltage, and plot the JV curve. The room temperature leakage current is obtained through the JV curve.

[0103] The results are shown in Table 1.

[0104] Table 1. Parameters and test results of Examples 1-6 and Comparative Examples 1-2

[0105] It can be seen from the above table: In Comparative Example 1, no pressure was applied to the sandwich structure during the sintering process. The resulting film had small coverage, large thickness deviation, high porosity, large surface roughness, and large deviation in molybdenum content, making it impossible to test its semiconductor performance normally.

[0106] Comparative Example 2, which uses excessively high sintering temperatures, produces films with large thickness deviations, making accurate thickness measurement impossible. The films also exhibit high porosity, low coverage, high surface roughness, and large deviations in molybdenum content, thus making it impossible to properly test their semiconductor performance.

[0107] Compared with Comparative Examples 1-2, the thin film of this application has uniform thickness, low porosity, high coverage, low surface roughness, and small element content deviation. Furthermore, the semiconductor performance of the thin film of this application is significantly improved.

[0108] Example 6 uses a longer sintering time, resulting in a thicker film, which leads to cracking, poor thickness uniformity, and high film surface roughness. In contrast, the films in Examples 1-5 of this application have better thickness uniformity, lower surface roughness, and significantly improved semiconductor performance.

[0109] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A wafer-level aluminum molybdate thin film, characterized in that, The wafer-level aluminum molybdate thin film includes a wafer substrate and a thin film disposed on at least one side of the wafer substrate, wherein a plurality of protrusions are formed on the surface of the wafer substrate facing the thin film, the wafer substrate is a sapphire substrate, and the thin film includes aluminum molybdate.

2. The wafer-level aluminum molybdate thin film according to claim 1, characterized in that, The plurality of protrusions satisfy one or more of the following characteristics: The height of each of the plurality of protrusions is independently greater than 0 and less than or equal to 1.5 µm; The height difference between the plurality of protrusions is <1.5 µm; The spacing between adjacent protrusions is 0.5 µm-5 µm; The shapes of the plurality of protrusions projected onto the surface of the wafer substrate are each independently selected from one or more of circles, triangles, and squares; Each of the plurality of protrusions projects an area of ​​0.2 µm onto the surface of the wafer substrate. 2 -20 µm 2 ; The difference in the projected area of ​​the plurality of protrusions on the surface of the wafer substrate is ≤5 µm 2 ; Each of the protrusions has an independent tip or a plane at its tip.

3. The wafer-level aluminum molybdate thin film according to claim 1, characterized in that, The protrusions are conical in shape.

4. The wafer-level aluminum molybdate thin film according to claim 1, characterized in that, The thin film satisfies one or more of the following characteristics: The thickness of the film is 1500 nm - 2500 nm; The thickness uniformity deviation of the film is <5%; The porosity of the film is ≤1 / 100; Based on the area of ​​the wafer substrate facing the thin film, the area of ​​the thin film accounts for ≥85%; The X-ray diffraction pattern of the thin film includes a characteristic peak with a 2θ of 12°-13°, and the full width at half maximum (FWHM) of the characteristic peak is 0.01° - 0.5°. The root mean square roughness of the thin film surface is ≤20 nm; The content deviation of molybdenum, aluminum and oxygen in any two regions of the film is ≤5% independently.

5. The wafer-level aluminum molybdate thin film according to any one of claims 1 to 4, characterized in that, The crystal orientation of the sapphire substrate is selected from any one of (0001), (11-20), (10-10), and (1-102); and / or, The thickness of the wafer substrate is 0.3 mm - 1 mm; and / or, The diameter of the wafer substrate is 5 cm - 31 cm.

6. A method for preparing wafer-level aluminum molybdate thin films, characterized in that, The method includes: A wafer substrate and a metal foil are alternately arranged to form a stacked structure; before the alternation, a plurality of protrusions are formed on the surface of the wafer substrate facing the metal foil; wherein the wafer substrate is a sapphire substrate and the metal foil includes molybdenum metal; A pressure greater than 0 and less than or equal to 0.05 MPa is applied to the two opposite outer sides of the stacked structure, and the pressurized state is maintained. The stacked structure is then sintered in an oxygen-containing atmosphere at 700℃-750℃ for 1-8 hours to obtain a wafer-level aluminum molybdate film. The wafer-level aluminum molybdate film includes a wafer substrate and a film disposed on at least one side of the wafer substrate, and the film includes aluminum molybdate.

7. The method according to claim 6, characterized in that, The plurality of protrusions satisfy one or more of the following characteristics: The height of each of the plurality of protrusions is independently greater than 0 and less than or equal to 1.5 µm; The height difference between the plurality of protrusions is ≤1.5 µm; The spacing between adjacent protrusions is 0.5 µm-5 µm; The shapes of the plurality of protrusions projected onto the surface of the wafer substrate are each independently selected from one or more of circles, triangles, and squares; Each of the plurality of protrusions projects an area of ​​0.2 µm onto the surface of the wafer substrate. 2 -20 µm 2 ; The difference in the projected area of ​​the plurality of protrusions on the surface of the wafer substrate is ≤5 µm 2 ; Each of the protrusions has an independent tip or a plane at its tip.

8. The method according to claim 6, characterized in that, The protrusions are conical in shape.

9. The method according to any one of claims 6 to 8, characterized in that, The method satisfies one or more of the following characteristics: During the sintering process, the thickness of the laminated structure is set along the vertical or horizontal direction; The number of the wafer substrate and the metal foil are each independently one or more; Cooling is performed after sintering; The thickness of the metal foil is 0.01 mm to 0.5 mm; The crystal orientation of the sapphire substrate is selected from any one of (0001), (11-20), (10-10), and (1-102); The thickness of the wafer substrate is 0.3 mm - 1 mm; The diameter of the wafer substrate is 5 cm - 31 cm.

10. A packaging method, characterized in that, include: A wafer-level aluminum molybdate film is provided, wherein the wafer-level aluminum molybdate film is the wafer-level aluminum molybdate film according to any one of claims 1 to 5 or the wafer-level aluminum molybdate film prepared by the method according to any one of claims 6 to 9; A first conductive layer is disposed on the surface of the wafer-level aluminum molybdate thin film; A temporary carrier plate is disposed on the surface of the first conductive layer; The wafer substrate is peeled off from the wafer-level aluminum molybdate film; A second conductive layer is deposited on the exposed surface of the film after peeling to form a stacked structure; The stacked structure is transferred to the target substrate and permanently bonded. The temporary carrier board is then removed to obtain the packaged structure.

11. A semiconductor device, characterized in that, include: The dielectric layer is a wafer-level aluminum molybdate film according to any one of claims 1 to 5 or a wafer-level aluminum molybdate film prepared by the method according to any one of claims 6 to 9. The first conductive layer and the second conductive layer are respectively disposed on both sides of the dielectric layer; The target substrate is disposed on the side of the first conductive layer or the second conductive layer away from the dielectric layer.

12. The semiconductor device according to claim 11, characterized in that, The semiconductor device is selected from one or more of the following: microelectronic devices, optoelectronic devices, integrated passive devices, and sensor devices.

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