A method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation

Abstract

The disclosed embodiments provide a method for repairing the surface shape of a SiC single crystal substrate after hydrogen ion implantation. The method repairs the surface shape of the SiC single crystal substrate after ion implantation by utilizing the temperature-dependent thermal expansion characteristics of a grinding wheel. Since the grinding wheel dissipates heat at different rates at the edge and the middle of the wheel surface after grinding and heating, the edge and the middle of the wheel surface expand at different rates, resulting in different contact areas and extrusion forces between the edge and the middle of the wheel surface and the SiC single crystal substrate. By controlling the range of temperature rise during grinding and the degree of deformation of the grinding wheel, the concave surface of the SiC single crystal substrate is squeezed into a flat surface under the combined action of extrusion and grinding fluid, thereby achieving the purpose of repairing the surface shape of the SiC single crystal substrate.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor processing technology, and in particular to a method for repairing the surface shape of a SiC single crystal substrate after hydrogen ion implantation. Background Art

[0002] Silicon carbide (SiC) is an important material in the third generation of semiconductors. It has excellent properties such as wide bandgap, high breakdown electric field, high thermal conductivity, high thermal stability and high chemical inertness. In recent years, reducing the cost share of 6 / 8-inch SiC single crystal substrates in the device end has become a consensus in the industry, and how to reduce the cost of SiC single crystal substrates has become the key. SiC single crystal substrates usually use physical vapor transport (PVT) for crystal growth. It is difficult to increase the growth rate and improve the yield in a short period of time. Therefore, improving the utilization rate of SiC materials has become the main direction of cost reduction in the short term. As a result, the preparation of SiC single crystal thin layers by SiC intelligent peeling technology combining ion implantation and bonding process has become a hot topic. Specifically, high-quality SiC single crystal thin layer transfer is achieved through hydrogen ion implantation, peeling and bonding technology. The SiC single crystal substrate can be reused, reducing material consumption, and obtaining high-quality single crystal thin layers, which significantly improves the performance of SiC-based devices. However, high-quality SiC direct bonding has become the most critical technology for the realization of this technology.

[0003] High-quality SiC direct bonding requires strict control of the bow / warp profile of the SiC single crystal substrate for the following reasons: 1) Ensuring close interface contact and minimizing defects: Direct bonding relies on atomic-level contact between the two substrate surfaces. If the surfaces are uneven, micron- or nanometer-scale voids will be generated during bonding. These defects significantly reduce bond strength and act as carrier scattering centers in the device, affecting electrical performance and reliability. 2) If the bonding interface has a mismatched profile, high-temperature processing or temperature fluctuations during subsequent processes can lead to interfacial stress concentration, causing surface cracks or delamination.

[0004] However, after single-sided hydrogen ion implantation of a SiC single crystal substrate, experiments have shown that the surface shape of the SiC single crystal substrate will undergo significant changes. Taking a 6-inch SiC single crystal substrate as an example, the surface shape changes of the SiC single crystal substrate before and after hydrogen ion implantation are shown in the following table:

[0005]

[0006] Note: >250 means the Bow / Warp value is too large and exceeds the detection limit of the equipment (250μm)

[0007] Therefore, it is very important to control the surface shape of the SiC single crystal substrate after hydrogen ion implantation and before bonding. Summary of the Invention

[0008] In view of this, an embodiment of the present disclosure provides a method for repairing the surface shape of a SiC single crystal substrate after hydrogen ion implantation, so as to solve the problem of deterioration of the surface shape of the SiC single crystal substrate after hydrogen ion implantation, and to control the surface shape of the SiC substrate before bonding to prevent voids defects and low bonding force during the bonding process.

[0009] The present disclosure provides a method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation, comprising:

[0010] S1. Performing surface inspection on multiple SiC single crystal substrates after hydrogen ion implantation to detect curvature and warpage;

[0011] S2. Continuously grouping the SiC single crystal substrates whose curvature is greater than or equal to the first preset value according to the span between the maximum and minimum curvature values ​​within a second preset value;

[0012] S3, provide thermal expansion coefficient range of 15×10 -6 / ℃~24×10 -6 / °C grinding wheels, determining the concavity of the grinding wheels corresponding to the curvature of the SiC single crystal substrates in each group according to the grouping conditions, so as to perform disc carving and trimming processing on the grinding wheels, and groove the grinding wheels with the concavity to form an annular groove;

[0013] S4, attaching the hydrogen ion implanted surfaces of the SiC single crystal substrates of the same group to the same ceramic disk, bringing the non-implanted surfaces of the SiC single crystal substrates attached to the ceramic disk into contact with the grinding disk, fixing the grinding head of a single-side grinder and the ceramic disk, dripping a grinding liquid onto the surface of the grinding disk to grind the SiC single crystal substrates;

[0014] S5. During the grinding process, controlling the surface temperature of the grinding wheel to be 25-45° C. to ensure that the grinding wheel is deformed to repair the surface shape of the SiC single crystal substrate;

[0015] S6, removing the SiC single crystal substrate and cleaning the SiC single crystal substrate;

[0016] S7. Detect the curvature and warpage of each of the SiC single crystal substrates to determine whether the curvature is less than the first preset value, and determine whether the warpage is less than the third preset value; if so, the repair is successful; if not, execute steps S4 to S7 until the curvature is less than the first preset value and the warpage is less than the third preset value.

[0017] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiment of the present disclosure, in step S1, the hydrogen ion implantation depth is 0.5-3 μm, and the hydrogen ion implantation dose is 1×10 14 ~1×10 17 cm -2 The injection energy of hydrogen ions is 60~400 KeV.

[0018] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S2, the first preset value is 30 μm, and the second preset value is 50±5 μm;

[0019] The SiC single crystal substrates with a curvature greater than or equal to a first preset value are divided into four groups: the curvature corresponding to the first group is [30, 80) μm, the curvature corresponding to the second group is [80, 130) μm, the curvature corresponding to the third group is [130, 180) μm, and the curvature corresponding to the fourth group is [180, 230) μm.

[0020] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S3, the concavity of the grinding disc corresponding to the first group is 40±10 μm, the concavity of the grinding disc corresponding to the second group is 65±10 μm, the concavity of the grinding disc corresponding to the third group is 90±10 μm, and the concavity of the grinding disc corresponding to the fourth group is 115±10 μm.

[0021] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the above-mentioned embodiment of the present disclosure, in step S3, the center of the grinding wheel has an opening extending through its thickness, the diameter of the grinding wheel is 720~1080 mm, the thickness of the grinding wheel is 5~30 mm, the planar shape of the annular groove is a spiral or concentric ring centered on the center point of the grinding wheel surface, the cross-sectional shape of the annular groove along the diameter direction of the grinding wheel surface is V-shaped or U-shaped, the depth of the annular groove is 0.5~0.8 mm, and the spacing between the annular grooves is 1~10 mm.

[0022] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S4, the step of attaching the hydrogen ion implanted surfaces of the SiC single crystal substrates of the same group to the same ceramic plate specifically includes:

[0023] The hydrogen ion implantation surfaces of the SiC single crystal substrates of the same group are attached to the same ceramic disk by using a wax attachment process or an adsorption pad.

[0024] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S4, the fixing of the grinding head of the single-side grinding machine and the ceramic disc specifically includes:

[0025] The grinding head of the single-side grinder is aligned with the edge of the ceramic disc, and the grinding head and the ceramic disc are completely inlaid.

[0026] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S4, the parameters of the grinding process include: the grinding pressure is 15-30 kg / piece, the rotation speed of the ceramic disc driven by the grinding head is 40~60 r / min, the rotation speed of the grinding disc is 20~35 r / min, the grinding liquid is a nano-diamond grinding liquid with a particle size of 0.1~0.3 μm, the flow rate of adding the grinding liquid is 0.003~0.02 L / min, the thickness of the SiC single crystal substrate ground off is 3~10 μm, and the grinding process time is 5~20 min.

[0027] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, the grinding disk is any one of a pure copper disk, a brass disk, an aluminum alloy disk, and a copper-nickel alloy disk.

[0028] In some embodiments, in the surface repair method of the SiC single crystal substrate after hydrogen ion implantation provided in the embodiments of the present disclosure, in step S6, the SiC single crystal substrate is removed and cleaned, specifically including:

[0029] The ceramic disk with the SiC single crystal substrate attached thereto is placed on a heating platform, and the ceramic disk is heated. After dewaxing, the SiC single crystal substrate is removed, and organic tank cleaning and RCA cleaning are performed on the SiC single crystal substrate.

[0030] The beneficial effects of the present disclosure are as follows:

[0031] The disclosed embodiments provide a method for repairing the surface shape of a SiC single crystal substrate after hydrogen ion implantation. The method repairs the surface shape of the SiC single crystal substrate after ion implantation by utilizing the temperature-dependent thermal expansion characteristics of a grinding wheel. Due to the different heat dissipation rates at the edge and the middle of the grinding wheel surface after grinding and heating, the edge and the middle of the grinding wheel surface expand at different rates, resulting in different contact areas and extrusion forces between the edge and the middle of the grinding wheel surface and the SiC single crystal substrate. By controlling the range of temperature rise during grinding and the degree of deformation of the grinding wheel surface, the concave surface of the SiC single crystal substrate is squeezed into a flat surface under the combined action of extrusion and grinding fluid, thereby achieving the purpose of repairing the surface shape of the SiC single crystal substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of ultrasonic void defect in SiC single crystal substrate implanted with hydrogen ions after bonding;

[0033] Figure 2 It is a plan view of a copper plate;

[0034] Figure 3 This is another plan view of the copper plate;

[0035] Figure 4 Schematic diagram of the concavity h corresponding to the surface of the copper plate being carved into a concave shape;

[0036] Figure 5 After the copper plate is heated, the surface of the copper plate is Figure 4 The concave shape shown becomes a convex shape. DETAILED DESCRIPTION

[0037] To further clarify the objectives, technical solutions, and advantages of the embodiments of the present disclosure, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present disclosure. It should be noted that in the drawings, the thicknesses of layers, films, panels, regions, etc. are exaggerated for clarity. In this disclosure, exemplary embodiments are described with reference to cross-sectional views that are schematic representations of idealized embodiments. As such, deviations from the shapes shown in the drawings are to be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments described in this disclosure should not be construed as limited to the specific shapes of the regions shown in this disclosure, but rather include deviations in shape resulting from, for example, manufacturing. For example, a region illustrated or described as flat may typically have rough and / or nonlinear features; a sharp angle illustrated may be rounded, etc. Therefore, the regions shown in the drawings are schematic in nature, and their sizes and shapes do not represent the exact shapes of the illustrated regions or are not true to scale. They are intended solely to illustrate the present disclosure. Throughout, identical or similar reference numerals denote identical or similar elements or elements having identical or similar functions. In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of known functions and known components.

[0038] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar terms used in the present disclosure and the claims do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Inside", "outside", "upper", "lower" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0039] In the following description, when an element or layer is referred to as being “on” or “connected to” another element or layer, the element or layer may be directly on, directly connected to, or there may be intermediate elements or layers. When an element or layer is referred to as being “disposed on one side of” another element or layer, the element or layer may be directly on, directly connected to, or there may be intermediate elements or layers. However, when an element or layer is referred to as being “directly on” or “directly connected to” another element or layer, there are no intermediate elements or layers. The term “and / or” includes any and all combinations of one or more of the associated listed items.

[0040] After hydrogen ion implantation, the surface of the SiC single crystal substrate will deteriorate, which is not conducive to the subsequent bonding process and easily causes defects such as voids and cleavage at the bonding interface. Figure 1 As shown, Figure 1 This is a schematic diagram of the ultrasonic void defect of the SiC single crystal substrate implanted with hydrogen ions after bonding. It can be seen that there are defects such as voids and cleavage at the bonding interface (indicated by red dots).

[0041] In view of this, in order to solve the problem of deterioration of the surface shape of the SiC single crystal substrate after hydrogen ion implantation, the embodiment of the present disclosure provides a surface shape repair method of the SiC single crystal substrate after hydrogen ion implantation. The surface shape repair method is described in detail below with a specific embodiment.

[0042] In embodiment 1, the method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation may specifically include the following steps:

[0043] S1. Use a surface profile tester (FRT or Tropel) to test the bow and warp of multiple 6-inch or 8-inch SiC single crystal substrates after hydrogen ion implantation. The hydrogen ion implantation depth is 0.5~3μm, and the hydrogen ion implantation dose is 1×10 14 ~1×10 17 cm -2 The injection energy of hydrogen ions is 60~400 KeV.

[0044] S2. SiC single crystal substrates with a bow greater than or equal to a first preset value are grouped consecutively according to the span between the maximum and minimum values ​​of the bow within a second preset value. For example, the first preset value is 30 μm, meaning that surfaces with a bow less than 30 μm are in good condition and do not require repair. The second preset value may be 50±5 μm, and in this embodiment, the second preset value is 50 μm. For example, SiC single crystal substrates with a bow greater than or equal to 30 μm are divided into four groups: the first group of SiC single crystal substrates corresponds to a bow of [30, 80) μm, the second group of SiC single crystal substrates corresponds to a bow of [80, 130) μm, the third group of SiC single crystal substrates corresponds to a bow of [130, 180) μm, and the fourth group of SiC single crystal substrates corresponds to a bow of [180, 230) μm. Of course, the present invention is not limited to four groups.

[0045] S3, provide thermal expansion coefficient range of 15×10 -6 / ℃~24×10 -6 / ℃ grinding disc, for example, the grinding disc is any one of a pure copper disc, a brass disc (a small amount of zinc is doped in the copper disc), an aluminum alloy disc, and a copper-nickel alloy disc. In this embodiment, a pure copper disc (hereinafter referred to as the copper disc) is used, and the purity of the copper disc is above 99.9%. Figure 2 and Figure 3 As shown, Figure 2 This is a plan view of a copper plate. Figure 3 FIG2 is another planar schematic diagram of a copper disk having an opening extending through the center of the copper disk. The diameter AB of the copper disk is 720 to 1080 mm, and the thickness of the copper disk is 5 to 30 mm. Based on the grouping in step S2, the concavity of the copper disk corresponding to the curvature of each group of SiC single crystal substrates is determined, and the copper disk is engraved. The surface of the engraved copper disk is ground with a trimming disk to remove surface burrs and polished to a mirror finish to ensure a close fit with the SiC single crystal substrate. Figure 2-Figure 4 As shown, Figure 2 and Figure 3 DE in the figure represents the approximate area where the concavity of the copper disk is measured. Figure 4: is a schematic diagram of the concavity h corresponding to the copper disk surface being engraved into a concave shape, where the concavity h is the distance between the center of DE and the horizontal plane (dashed line). For example, the concavity h of the copper disk corresponding to the first group of curvatures [30, 80) μm is 40±10 μm. In this embodiment, the concavity h of the copper disk corresponding to the first group is 40 μm; the concavity h of the copper disk corresponding to the second group of curvatures [80, 130) μm is 65±10 μm. In this embodiment, the concavity h of the copper disk corresponding to the second group is 65 μm; the concavity h of the copper disk corresponding to the third group of curvatures [130, 180) is 90±10 μm. In this embodiment, the concavity h of the copper disk corresponding to the third group is 90 μm; the concavity h of the copper disk corresponding to the fourth group of curvatures [180, 230) μm is 115±10 μm. In this embodiment, the concavity h of the copper disk corresponding to the fourth group is 115 μm. Then, a V-shaped diamond tool is used to carve a groove on the concave copper disk surface to form an annular groove. The annular groove design is conducive to the flow of the grinding fluid during subsequent grinding. Figure 2 As shown, the plane shape of the annular groove (shown by the dotted line) is a spiral with the center point C of the copper disk as the center, as shown in FIG. Figure 3 As shown, the planar shape of the annular groove (shown by the dotted line) is a concentric ring centered at the center point C of the copper disk surface. The cross-sectional shape of the annular groove along the diameter AB direction of the copper disk surface is V-shaped or U-shaped. The groove engraving method of the copper disk in this embodiment adopts the following method: Figure 2 Taking the spiral V-grooves shown as an example, the annular groove depth can be 0.5-0.8 mm, and the spacing between the annular grooves can be 1-10 mm. Specifically, each group of SiC single crystal substrates can correspond to a copper disk, and the corresponding concavity of the copper disk can be designed for different groups of bows, while also controlling the groove shape (V-shaped or U-shaped) of the copper disk. Alternatively, each group of SiC single crystal substrates can correspond to the same copper disk, and the disk can be engraved according to the corresponding concavity of each group.

[0046] S4, such as Figure 2As shown, a ceramic disk is prepared, and the hydrogen ion implanted surfaces of the same group of SiC single crystal substrates are attached to the same ceramic disk using a waxing process. After solidification, the non-implanted surface of the SiC single crystal substrate attached to the ceramic disk is brought into contact with the copper disk, that is, the ceramic disk with the SiC single crystal substrate attached is placed on the surface of the copper disk, and then the grinding head of the single-side grinder and the ceramic disk are fixed, for example, the grinding head of the single-side grinder is aligned with the edge of the ceramic disk, the grinding head and the ceramic disk are completely embedded, and particles with a diameter of 0.1 to 0 are dropped on the surface of the copper disk. The SiC single crystal substrate is ground with a nano-diamond grinding liquid of 0.3μm. The grinding pressure is 15-30kg / piece. The rotation speed of the ceramic disk driven by the grinding head is 40-60r / min, the rotation speed of the copper disk is 20-35r / min, the flow rate of the added grinding liquid is 0.003-0.02L / min, the thickness of the SiC single crystal substrate is ground off to 3-10μm, and the grinding time is 5-20min. The specific processing time is determined according to the surface shape of the SiC single crystal substrate.

[0047] Optionally, in step S4 above, the adsorption pad may be attached to the ceramic disk, and then the implantation surface of the SiC single crystal substrate may be adsorbed onto the adsorption pad, so that the hydrogen ion implantation surfaces of the same group of SiC single crystal substrates are attached to the same ceramic disk.

[0048] S5. During the grinding process, observe the surface temperature of the copper disk and control the surface temperature of the copper disk to 25~45℃. Further, the surface temperature of the copper disk can be controlled to 28~36℃ to ensure that the copper disk produces appropriate deformation to achieve the surface shape of the SiC single crystal substrate. Figure 5 As shown, Figure 5 When the copper plate is heated, the surface of the copper plate is Figure 4 The concave shape shown becomes Figure 5 Then, when the SiC single crystal substrate is repaired on the surface, the surface temperature of the SiC single crystal substrate is controlled when it is processed on the copper disk to control the deformation of the copper disk. Under the condition of using nano-diamond grinding liquid as a grinding auxiliary material, the purpose of repairing the surface of different SiC single crystal substrates after hydrogen ion implantation is achieved. Specifically, Figure 2As shown, a ceramic disk is rotated and ground on a copper disk, and the ceramic disk moves close to the edge of the copper disk. The hydrogen ion implanted surface of the SiC single crystal substrate is generally convex, and the non-implanted surface (the surface in contact with the copper disk) is concave. The copper disk contacts the edge region of the SiC single crystal substrate, but the central region of the SiC single crystal substrate may not be completely in contact with the copper disk due to the concave surface. The present disclosure repairs the surface shape of the SiC single crystal substrate after ion implantation by utilizing the temperature-dependent thermal expansion coefficient of the copper disk. Due to the different heat dissipation rates of the copper disk edge and the middle of the disk surface after grinding and heating, the copper disk edge and the middle of the disk surface expand at different rates, resulting in different contact areas and extrusion forces between the copper disk edge and the middle of the disk surface and the SiC single crystal substrate. By controlling the range of temperature rise during grinding and the degree of deformation of the copper disk, the concave surface of the SiC single crystal substrate is squeezed into a flat surface under the combined action of extrusion and grinding fluid, thereby achieving the purpose of repairing the surface shape of the SiC single crystal substrate.

[0049] S6. Place the ceramic disk with the SiC single crystal substrate on a heating platform, heat the ceramic disk, remove the SiC single crystal substrate after dewaxing, and perform organic tank cleaning and RCA cleaning on the SiC single crystal substrate.

[0050] S7. Detect the bow and warp of each SiC single crystal substrate to determine whether the bow is less than a first preset value (30 μm) and whether the warp is less than a third preset value (e.g., 30 μm). If so, the repair is successful. If not, perform steps S4 to S7 above to repair again until the bow is less than the first preset value (30 μm) and the warp is less than the third preset value (30 μm).

[0051] In summary, the present disclosure utilizes the deformation of the copper disk during the grinding process and the use of nanodiamond polishing slurry to repair the surface shape of the SiC single crystal substrate after hydrogen ion implantation. This is a precision correction technology based on mechanical stress regulation. The repair method disclosed in the present disclosure mainly includes the following two points:

[0052] (1) Deformation transfer mechanism: The thermal expansion characteristics of the copper disk are utilized to apply controllable stress (mechanical force and thermal stress) to cause it to undergo elastic deformation, and then the deformation is transferred to the SiC single crystal substrate to compensate for the original surface error of the SiC single crystal substrate (such as bow-convexity, warp, etc.).

[0053] (2) Stress matching: The differences in elastic modulus and thermal expansion coefficient between the copper disk and the SiC single crystal substrate material need to be accurately calculated, and then the corresponding relationship between the concavity of the copper disk and the surface shape of the SiC single crystal substrate to be repaired is summarized based on process experience to ensure that the deformation is controllable and no secondary damage is introduced.

[0054] The difference between Example 2 and Example 1 is that the grooves of the copper plate in this embodiment are cut as follows: Figure 3 The concentric ring grooving method shown.

[0055] The difference between Example 3 and Example 1 is that the grooves of the copper plate in this embodiment are cut as follows: Figure 2 The spiral grooving method shown is a U-shaped groove with a spacing of 2 to 8 mm between the annular grooves.

[0056] Example 4 differs from Example 1 in that the pure copper disk is replaced with a brass disk.

[0057] Example 5 differs from Example 2 in that the pure copper disk is replaced with a copper-nickel alloy disk.

[0058] Example 6 differs from Example 3 in that the pure copper disk is replaced with an aluminum alloy disk.

[0059] Through the above Examples 1-6, the present disclosure realizes the surface repair of the SiC single crystal substrate after hydrogen ion implantation. For example, after hydrogen ion implantation: the Bow of the 6-inch SiC single crystal substrate is repaired from >100μm, or even >250μm, to <30μm; the Warp of the 6-inch SiC single crystal substrate is repaired from >100μm, or even >250μm, to <40μm; the Bow of the 8-inch SiC single crystal substrate is repaired from >100μm, or even >250μm, to <40μm; and the Warp of the 8-inch SiC single crystal substrate is repaired from >100μm, or even >250μm, to <50μm. Ultimately, the goal of no defects such as voids on the interface of the SiC single crystal substrate after bonding and a bonding force of >1.0J / m² is achieved. The direct bonding and peeling processes in the SiC smart peeling technology are successfully realized, solving the high cost and low yield in traditional substrate manufacturing, and will further promote the development of silicon carbide single crystal substrates towards larger size, higher performance, and lower cost.

[0060] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure.

[0061] Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation, characterized in that: include: S1. Performing surface inspection on multiple SiC single crystal substrates after hydrogen ion implantation to detect curvature and warpage; S2. Continuously grouping the SiC single crystal substrates with a curvature greater than or equal to a first preset value according to a span between a maximum value and a minimum value of the curvature within a second preset value, where the first preset value is 30 μm and the second preset value is 50±5 μm; dividing the SiC single crystal substrates with a curvature greater than or equal to the first preset value into four groups: the first group corresponds to a curvature of [30, 80) μm, the second group corresponds to a curvature of [80, 130) μm, the third group corresponds to a curvature of [130, 180) μm, and the fourth group corresponds to a curvature of [180, 230) μm; S3, provide thermal expansion coefficient range of 15×10 -6 / ℃~24×10 -6 / °C grinding wheels, determining the concavity of the grinding wheels corresponding to the curvature of the SiC single crystal substrates in each group according to the grouping, performing disc carving and trimming on the grinding wheels, and carving annular grooves on the surfaces of the grinding wheels having the concavity; wherein the concavity of the grinding wheels corresponding to the first group is 40±10 μm, the concavity of the grinding wheels corresponding to the second group is 65±10 μm, the concavity of the grinding wheels corresponding to the third group is 90±10 μm, and the concavity of the grinding wheels corresponding to the fourth group is 115±10 μm; S4, attaching the hydrogen ion implanted surfaces of the SiC single crystal substrates of the same group to the same ceramic disk, bringing the non-implanted surfaces of the SiC single crystal substrates attached to the ceramic disk into contact with the grinding disk, fixing the grinding head of a single-side grinder and the ceramic disk, dripping a grinding liquid onto the surface of the grinding disk to grind the SiC single crystal substrates; S5. During the grinding process, controlling the surface temperature of the grinding wheel to be 25-45° C. to ensure that the grinding wheel is deformed to repair the surface shape of the SiC single crystal substrate; S6, removing the SiC single crystal substrate and cleaning the SiC single crystal substrate; S7. Detect the curvature and warpage of each of the SiC single crystal substrates to determine whether the curvature is less than the first preset value, and determine whether the warpage is less than the third preset value; if so, the repair is successful; if not, execute steps S4 to S7 until the curvature is less than the first preset value and the warpage is less than the third preset value.

2. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S1, the hydrogen ion implantation depth is 0.5-3 μm, and the hydrogen ion implantation dose is 1×10 14 ~1×10 17 cm -2 The injection energy of hydrogen ions is 60~400 KeV.

3. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S3, the center of the grinding disk has an opening that penetrates its thickness, the diameter of the grinding disk is 720~1080 mm, the thickness of the grinding disk is 5~30 mm, the planar shape of the annular groove is a spiral or concentric ring centered on the center point of the grinding disk surface, the cross-sectional shape of the annular groove along the diameter direction of the grinding disk surface is V-shaped or U-shaped, the depth of the annular groove is 0.5~0.8 mm, and the spacing of the annular grooves is 1~10 mm.

4. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S4, the step of attaching the hydrogen ion implanted surfaces of the SiC single crystal substrates of the same group to the same ceramic plate specifically includes: The hydrogen ion implantation surfaces of the SiC single crystal substrates of the same group are attached to the same ceramic disk by using a wax attachment process or an adsorption pad.

5. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S4, the fixing of the grinding head of the single-side grinding machine and the ceramic disc specifically includes: The grinding head of the single-side grinder is aligned with the edge of the ceramic disc, and the grinding head and the ceramic disc are completely inlaid.

6. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S4, the parameters of the grinding process include: the grinding pressure is 15-30 kg / piece, the rotation speed of the ceramic disc driven by the grinding head is 40~60 r / min, the rotation speed of the grinding disc is 20~35 r / min, the grinding liquid is a nano-diamond grinding liquid with a particle size of 0.1~0.3 μm, the flow rate of adding the grinding liquid is 0.003~0.02 L / min, the thickness of the SiC single crystal substrate ground off is 3~10 μm, and the grinding process time is 5~20 min.

7. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: The grinding disc is any one of a pure copper disc, a brass disc, an aluminum alloy disc, and a copper-nickel alloy disc.

8. The method for repairing the surface of a SiC single crystal substrate after hydrogen ion implantation according to claim 1, wherein: In step S6, the SiC single crystal substrate is removed and cleaned, which specifically includes: The ceramic disk with the SiC single crystal substrate attached thereto is placed on a heating platform, and the ceramic disk is heated. After dewaxing, the SiC single crystal substrate is removed, and organic tank cleaning and RCA cleaning are performed on the SiC single crystal substrate.

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