Machining method and machining system for controlling surface type of large-size silicon carbide substrate

Abstract

The invention provides a processing method and a processing system for controlling the surface type of a large-size silicon carbide substrate, and relates to the technical field of semiconductor substrate processing. According to the technical scheme, before the silicon carbide wafer is thinned, the target wafer curvature is obtained through analysis according to the linear relation between the wafer double-face grinding removal amount and the wafer curvature, if the target wafer curvature meets the expectation, double-face grinding is conducted on the silicon carbide wafer, and finally the silicon carbide substrate with the expected wafer curvature is obtained. The processing purpose of controlling the surface type of the silicon carbide substrate is achieved, and the product yield is improved. And when the bending degree of the target wafer does not conform to the expectation, the silicon carbide wafer does not need to be processed subsequently, so that materials are saved, and the preparation cost of the silicon carbide substrate is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor substrate processing, and more specifically, to a processing method and a processing system for controlling the surface shape of a large-sized silicon carbide substrate. Background Art

[0002] In the field of chip manufacturing, the key indicator of the BOW (bending) of the chip is mainly affected by two core factors: the characteristics of the crystal itself and the multi-wire cutting process. From the perspective of the crystal itself, the arrangement of atoms, molecules or ions inside it constitutes a unique crystal structure, which not only determines the basic physical properties of the crystal, but also has a deep-rooted influence on the BOW of the chip. Taking silicon carbide crystal as an example, its high hardness, high critical breakdown field strength and other characteristics make it popular in cutting-edge fields such as semiconductors and power devices. However, during the growth of silicon carbide crystals, defects such as micropipes and dislocations are very easy to occur. These defects are hidden inside the silicon carbide crystal. Even if the growth of the silicon carbide crystal is completed and its properties have basically stabilized, these hidden defects will continue to interfere with the BOW state of the silicon carbide wafer when the silicon carbide crystal is sliced ​​and the silicon carbide wafer is ground and processed. For example, micropipe defects, the void structure formed in the silicon carbide crystal, will significantly change the stress distribution in the local area of ​​the silicon carbide crystal. When silicon carbide crystals are cut and the cut silicon carbide wafers are subjected to external stress during grinding and thinning, the silicon carbide wafers are more likely to bend and deform based on the changed stress distribution, which in turn has an adverse effect on the BOW index, making the surface shape of the prepared silicon carbide substrate uncontrollable, resulting in a low product yield and increased preparation cost of the silicon carbide substrate. Summary of the invention

[0003] In view of this, the present application provides a processing method and a processing system for controlling the surface shape of a large-sized silicon carbide substrate, which effectively solves the technical problems existing in the prior art. Based on the target wafer double-sided grinding removal amount obtained by analysis, the silicon carbide wafer is double-sided ground to obtain a silicon carbide substrate that meets the expected surface shape, thereby improving the product yield and reducing the preparation cost of the silicon carbide substrate.

[0004] To achieve the above objectives, the technical solutions provided by this application are as follows:

[0005] A processing method for controlling the surface shape of a large-sized silicon carbide substrate comprises:

[0006] Cutting the silicon carbide crystal to obtain silicon carbide wafers;

[0007] Based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, determining the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition, wherein the wafer double-side grinding removal amount is the total removal amount of the silicon surface and the carbon surface of the silicon carbide wafer to be ground;

[0008] Under the condition that the target wafer curvature meets the set curvature, the silicon carbide wafer is double-sided ground according to the target wafer double-sided grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0009] Optionally, determining the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature comprises:

[0010] Based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition is determined, wherein the linear relationship between the wafer double-side grinding removal amount and the wafer curvature is:

[0011] Y=AX+B;

[0012] Y is the curvature of the wafer, X is the amount of wafer double-sided grinding removed, A is a constant determined based on a double-sided grinding machine and double-sided grinding process experiment, and B is the crystal convexity of the silicon carbide crystal.

[0013] Optionally, the constant A determined based on the double-sided grinding machine and double-sided grinding process experiment has a value range of -2 to 2;

[0014] The value range of the crystal convexity B of the silicon carbide crystal is -5 to 8.

[0015] Optionally, the step of cutting the silicon carbide crystal to obtain a silicon carbide wafer comprises:

[0016] The silicon carbide crystal is cut by a multi-wire cutting process to obtain a silicon carbide wafer.

[0017] Optionally, performing double-side grinding on the silicon carbide wafer according to the target wafer double-side grinding removal amount includes:

[0018] The silicon surface and the carbon surface of the silicon carbide wafer are double-sided ground simultaneously according to the target wafer double-sided grinding removal amount.

[0019] Based on the same inventive concept, the present application also provides a processing system for controlling the surface shape of a large-sized silicon carbide substrate, comprising:

[0020] A cutting device, wherein the cutting device is used to cut the silicon carbide crystal to obtain a silicon carbide wafer;

[0021] A host computer, wherein the host computer determines a target wafer curvature of the silicon carbide wafer under a target wafer double-side grinding removal amount condition based on a linear relationship between a wafer double-side grinding removal amount and a wafer curvature, wherein the wafer double-side grinding removal amount is a total removal amount of a silicon surface and a carbon surface of the silicon carbide wafer to be ground;

[0022] A grinding and thinning device, when the target wafer curvature meets the set curvature condition, the grinding and thinning device performs double-sided grinding on the silicon carbide wafer according to the double-sided grinding removal amount of the target wafer to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0023] Optionally, the host computer determines the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, including:

[0024] The host computer determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-side grinding removal amount based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, wherein the linear relationship between the wafer double-side grinding removal amount and the wafer curvature is:

[0025] Y=AX+B;

[0026] Y is the curvature of the wafer, X is the amount of wafer double-sided grinding removed, A is a constant determined based on a double-sided grinding machine and double-sided grinding process experiment, and B is the crystal convexity of the silicon carbide crystal.

[0027] Optionally, the constant A determined based on the double-sided grinding machine and double-sided grinding process experiment has a value range of -2 to 2;

[0028] The value range of the crystal convexity B of the silicon carbide crystal is -5 to 8.

[0029] Optionally, the cutting device is used to cut the silicon carbide crystal to obtain the silicon carbide wafer, comprising:

[0030] The cutting device adopts a multi-wire cutting process to cut silicon carbide crystals to obtain silicon carbide wafers.

[0031] Optionally, the grinding and thinning device performs double-sided grinding on the silicon carbide wafer according to the target wafer double-sided grinding removal amount, comprising:

[0032] The grinding and thinning device simultaneously performs double-side grinding on the silicon surface and the carbon surface of the silicon carbide wafer according to the target wafer double-side grinding removal amount.

[0033] Compared with the prior art, the technical solution provided by this application has at least the following advantages:

[0034] The present application provides a processing method and a processing system for controlling the surface shape of a large-sized silicon carbide substrate, the processing method comprising: cutting a silicon carbide crystal to obtain a silicon carbide wafer; determining a target wafer curvature of the silicon carbide wafer under a target wafer double-side grinding removal amount condition based on a linear relationship between a wafer double-side grinding removal amount and a wafer curvature, wherein the wafer double-side grinding removal amount is a total removal amount of a silicon surface and a carbon surface of the silicon carbide wafer to be ground; under a condition that the target wafer curvature satisfies a set curvature, double-side grinding the silicon carbide wafer according to the target wafer double-side grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0035] As can be seen from the above content, the technical solution provided by the present application, before thinning the silicon carbide wafer, first analyzes the linear relationship between the amount of wafer double-sided grinding removal and the wafer curvature to obtain the target wafer curvature, and if the target wafer curvature meets expectations, the silicon carbide wafer is double-sided ground, and finally a silicon carbide substrate with the expected wafer curvature is obtained, achieving the processing purpose of controlling the surface shape of the silicon carbide substrate and improving the product yield. When the target wafer curvature does not meet expectations, there is no need to perform subsequent processing on the silicon carbide wafer, thereby saving materials and reducing the preparation cost of the silicon carbide substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 A flowchart of a processing method for controlling the surface shape of a large-sized silicon carbide substrate provided in an embodiment of the present application;

[0038] Figure 2 A schematic diagram of test results of a silicon carbide substrate provided in an embodiment of the present application;

[0039] Figure 3 A schematic diagram of test results of another silicon carbide substrate provided in an embodiment of the present application;

[0040] Figure 4 A schematic diagram of test results of another silicon carbide substrate provided in an embodiment of the present application;

[0041] Figure 5 A schematic structural diagram of a processing system for controlling the surface shape of a large-sized silicon carbide substrate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] As described in the background technology, in the field of wafer manufacturing, the key indicator of the BOW (bending) of the wafer is mainly affected by two core factors: the characteristics of the crystal itself and the multi-wire cutting process. From the perspective of the crystal itself, the arrangement of atoms, molecules or ions inside it constitutes a unique crystal structure, which not only determines the basic physical properties of the crystal, but also has a deep-rooted influence on the BOW of the wafer. Taking silicon carbide crystal as an example, its high hardness, high critical breakdown field strength and other characteristics make it popular in cutting-edge fields such as semiconductors and power devices. However, during the growth of silicon carbide crystals, defects such as micropipes and dislocations are very easy to occur. These defects are hidden inside the silicon carbide crystal. Even if the silicon carbide crystal is grown and its properties have basically stabilized, these hidden defects will continue to interfere with the BOW state of the silicon carbide wafer when the silicon carbide crystal is sliced ​​and the silicon carbide wafer is ground and processed. For example, micropipe defects, the void structure formed in the silicon carbide crystal, will significantly change the stress distribution in the local area of ​​the silicon carbide crystal. When silicon carbide crystals are cut and the cut silicon carbide wafers are subjected to external stress during grinding and thinning, the silicon carbide wafers are more likely to bend and deform based on the changed stress distribution, which in turn has an adverse effect on the BOW index, making the surface shape of the prepared silicon carbide substrate uncontrollable, resulting in a low product yield and increased preparation cost of the silicon carbide substrate.

[0044] Based on this, the embodiment of the present application provides a processing method and a processing system for controlling the surface shape of a large-size silicon carbide substrate, which effectively solves the technical problems existing in the prior art. Based on the target wafer double-sided grinding removal amount obtained by analysis, the silicon carbide wafer is double-sided ground to obtain a silicon carbide substrate that meets the expected surface shape, thereby improving the product yield and reducing the preparation cost of the silicon carbide substrate.

[0045] To achieve the above purpose, the technical solution provided in the embodiment of the present application is as follows, specifically combined with Figures 1 to 5 The technical solution provided by the embodiment of the present application is described in detail. It should be noted that the large-size silicon carbide substrate described in the present application is a silicon carbide substrate of 6 inches or larger.

[0046] refer to Figure 1As shown, it is a flow chart of a processing method for controlling the surface shape of a large-sized silicon carbide substrate provided in an embodiment of the present application, wherein the processing method provided in an embodiment of the present application includes:

[0047] S1. Cutting a silicon carbide crystal to obtain a silicon carbide wafer.

[0048] S2. Determine a target wafer curvature of the silicon carbide wafer under a target wafer double-side grinding removal amount condition based on a linear relationship between the wafer double-side grinding removal amount and the wafer curvature, wherein the wafer double-side grinding removal amount is a total removal amount of a silicon surface and a carbon surface of the silicon carbide wafer to be ground.

[0049] S3. When the target wafer curvature satisfies a set curvature condition, the silicon carbide wafer is double-sided ground according to the target wafer double-sided grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0050] It can be understood that the technical solution provided in the embodiment of the present application, before thinning the silicon carbide wafer, first analyzes the linear relationship between the amount of wafer double-sided grinding removal and the wafer curvature to obtain the target wafer curvature. If the target wafer curvature meets expectations, the silicon carbide wafer is double-sided ground, and finally a silicon carbide substrate with the expected wafer curvature is obtained, achieving the processing purpose of controlling the surface shape of the silicon carbide substrate and improving the product yield. When the target wafer curvature does not meet expectations, there is no need to perform subsequent processing on the silicon carbide wafer, thereby saving materials and reducing the preparation cost of the silicon carbide substrate.

[0051] In some embodiments, the cutting of silicon carbide crystals to obtain silicon carbide wafers provided in the embodiments of the present application includes: cutting silicon carbide crystals using a multi-wire cutting process to obtain silicon carbide wafers. The multi-wire cutting equipment is mainly composed of a pay-off shaft, a take-up shaft, a cutting wire, a guide wheel, a cutting fluid supply system, and a workbench. The cutting wire generally uses a high-strength steel wire or resin wire, which is wound between the pay-off shaft and the take-up shaft, and the tension and position accuracy of the cutting wire are maintained by multiple guide wheels. During the cutting process, the cutting wire circulates at a certain speed, and at the same time, the workbench drives the material to be cut to feed in the direction of the cutting wire. The cutting fluid and abrasive are mixed and transported to the cutting area, and the cutting fluid plays a role of cooling and lubrication, and the abrasive grinds the material under the drive of the cutting wire, thereby realizing the cutting of the material. By controlling the speed, tension, feed speed of the workbench, and supply parameters of the cutting wire, accurate cutting of different materials and different thicknesses can be achieved. The multi-wire cutting process uses multiple cutting wires to cut at the same time, and can complete the cutting of multiple slices at one time, greatly improving the cutting efficiency. With the continuous development of multi-wire cutting technology, the cutting capacity of the equipment has been continuously improved, and the cutting of large-sized silicon carbide crystals has been realized. This is of great significance for meeting the demand for large-sized silicon carbide wafers for high-power and high-voltage semiconductor devices, and helps to promote the widespread application of silicon carbide materials in power electronics and other fields.

[0052] In some embodiments, the double-sided grinding of the silicon carbide wafer according to the double-sided grinding removal amount of the target wafer provided in the embodiment of the present application includes: the silicon surface and the carbon surface of the silicon carbide wafer are simultaneously double-sided ground according to the double-sided grinding removal amount of the target wafer. After obtaining the thinned silicon carbide substrate, the silicon carbide substrate can be subjected to chemical mechanical polishing. It can be understood that the double-sided grinder can make the silicon carbide wafer be subjected to uniform grinding force during the grinding process through the relative movement of the upper and lower grinding discs and precise pressure control, thereby effectively ensuring the thickness uniformity of the wafer. In general, the thickness deviation of the silicon carbide wafer can be controlled within a very small range to meet the strict requirements of high-end applications for wafer thickness consistency. In addition, the upper and lower grinding discs of the double-sided grinder are processed and debugged with high precision during the manufacturing and installation process, and can maintain good parallelism. When grinding the silicon carbide wafer, this high-precision parallelism is transferred to the wafer, so that its surface flatness is significantly improved, which is conducive to subsequent photolithography, etching and other process operations. It should be noted that the upper grinding disc and the lower grinding disc are key components of the double-sided grinding machine to achieve double-sided grinding of wafers. Among them, the lower grinding disc rotates at high speed under the drive of the driving motor, providing the main power source for the grinding process. The upper grinding disc forms a relative motion with the lower grinding disc under the action of pressure, and the rotational motion of the two makes the wafer located between them receive a uniform grinding force, thereby achieving simultaneous grinding of the upper and lower surfaces of the wafer.

[0053] In some embodiments, the linear relationship between the wafer double-side grinding removal amount and the wafer curvature provided in the embodiments of the present application is used to determine the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition, including:

[0054] Based on the linear relationship between the double-sided grinding removal amount of the wafer and the wafer curvature, the target wafer curvature of the silicon carbide wafer under the target wafer double-sided grinding removal amount condition is determined, wherein the linear relationship between the double-sided grinding removal amount of the wafer and the wafer curvature is: Y=AX+B; Y is the wafer curvature, X is the double-sided grinding removal amount of the wafer, A is a constant determined based on the double-sided grinding machine and the double-sided grinding process experiment, which involves the grinding speed ratio of the upper grinding disc and the lower grinding disc of the double-sided grinding machine and other influencing factors, and B is the crystal convexity of the silicon carbide crystal. The applicant has found that there is a linear relationship between the double-sided grinding removal amount of the silicon carbide wafer and the wafer curvature. Based on this linear relationship, the wafer curvature under the grinding removal amount of the silicon carbide wafer can be analyzed before the silicon carbide wafer is ground and thinned, thereby achieving the processing purpose of controlling the surface shape of a large-sized silicon carbide substrate.

[0055] Specific combination Figures 2 to 4 The test result diagram shown in the figure, and the linear relationship between the double-sided grinding removal amount of the wafer and the wafer curvature are illustrated in combination with the following specific examples. It should be noted that the cutting process, double-sided grinding process, chemical mechanical polishing process and equipment used in Examples 1 to 3 are the same, and the same type of silicon carbide wafers are obtained by cutting the same column silicon carbide crystal. And, Figures 2 to 4 Rng is the distance between the highest point and the lowest point of the silicon carbide substrate (that is, the warpage 3pt Warp), Max is the highest point of the silicon carbide substrate, Min is the highest point of the silicon carbide substrate, and 3ptBOW is the curvature of the silicon carbide substrate.

[0056] Case 1: The multi-wire cutting process is used to cut the silicon carbide crystal to obtain a silicon carbide wafer. Then the double-sided grinding process is used to grind and thin the silicon carbide wafer to remove 35μm. Finally, the chemical mechanical polishing process is used to obtain a silicon carbide substrate.

[0057] Case 2: The multi-wire cutting process is used to cut the silicon carbide crystal to obtain a silicon carbide wafer. Then the double-sided grinding process is used to grind and thin the silicon carbide wafer to remove 70μm. Finally, the chemical mechanical polishing process is used to obtain a silicon carbide substrate.

[0058] Case 3: The multi-wire cutting process is used to cut the silicon carbide crystal to obtain a silicon carbide wafer. Then the double-sided grinding process is used to grind and thin the silicon carbide wafer to remove 110μm. Finally, the chemical mechanical polishing process is used to obtain a silicon carbide substrate.

[0059] The properties of the silicon carbide substrates prepared in Examples 1 to 3 above were tested, and specifically, the flatness measurement equipment FM200 was used for testing and characterization, and the results were shown in Table 1. Figure 2 , Figure 3 and Figure 4 The results are shown in Figure 2, where Figure 2 This is a schematic diagram of the test results of the silicon carbide substrate for Example 1. Figure 3 This is a schematic diagram of the test results of the silicon carbide substrate for Example 2. Figure 4 This is a schematic diagram of the test results of the silicon carbide substrate for Example 3. Figure 2 , Figure 3 and Figure 4 It can be shown that there is a linear relationship between the wafer double grinding removal amount X and the wafer curvature Y, that is, Y=AX+B, where A takes a value of -0.37 and B takes a value of -1.39.

[0060]

[0061] The above examples illustrate that the constants A and B obtained are only one of the values ​​applicable to this application. The applicant has found through research and experiments that the constant A determined based on the double-sided grinder and double-sided grinding process experiment provided in the embodiment of this application has a value range of -2 to 2; and the crystal convexity B of the silicon carbide crystal provided in the embodiment of this application has a value range of -5 to 8.

[0062] Based on the same inventive concept, the embodiment of the present application also provides a processing system for controlling the surface shape of a large-sized silicon carbide substrate. Figure 5 FIG. 1 is a schematic diagram of a structure of a processing system for controlling the surface shape of a large-sized silicon carbide substrate provided in an embodiment of the present application, wherein the processing system includes:

[0063] A cutting device 100, the cutting device 100 is used to cut a silicon carbide crystal to obtain a silicon carbide wafer. A host computer 200, the host computer 200 determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-sided grinding removal amount based on the linear relationship between the wafer double-sided grinding removal amount and the wafer curvature, wherein the wafer double-sided grinding removal amount is the total removal amount of the silicon surface and the carbon surface of the silicon carbide wafer to be ground; and a grinding and thinning device 300, under the condition that the target wafer curvature meets the set curvature, the grinding and thinning device 300 double-sided grinds the silicon carbide wafer according to the target wafer double-sided grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0064] In some embodiments, the host computer 200 provided in the embodiment of the present application may be an independent device, or the host computer 200 may be integrated into the grinding and thinning device 300, or integrated into other devices, and the present application does not make specific restrictions on this. In addition, the target wafer curvature provided in the embodiment of the present application may also be obtained by manual calculation by the staff according to the linear relationship, and the present application does not make specific restrictions on this, and only needs to obtain the target curvature. Optionally, the host computer 200 provided in the embodiment of the present application determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-sided grinding removal amount based on the linear relationship between the wafer double-sided grinding removal amount and the wafer curvature, including: the host computer 200 determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-sided grinding removal amount based on the linear relationship between the wafer double-sided grinding removal amount and the wafer curvature, wherein the linear relationship between the wafer double-sided grinding removal amount and the wafer curvature is: Y=AX+B; Y is the wafer curvature, X is the wafer double-sided grinding removal amount, A is a constant determined based on the double-sided grinding machine and the double-sided grinding process experiment, and B is the crystal convexity of the silicon carbide crystal. Optionally, the constant A determined based on the double-sided grinding machine and the double-sided grinding process experiment provided in the embodiment of the present application has a value range of -2 to 2; and the crystal convexity B of the silicon carbide crystal provided in the embodiment of the present application has a value range of -5 to 8.

[0065] In some embodiments, the cutting device 100 provided in the embodiment of the present application may be a multi-wire cutting device. That is, the cutting device 100 provided in the embodiment of the present application is used to cut silicon carbide crystals to obtain silicon carbide wafers, including: the cutting device 100 uses a multi-wire cutting process to cut silicon carbide crystals to obtain silicon carbide wafers. And, the grinding and thinning device 300 provided in the embodiment of the present application performs double-sided grinding of the silicon carbide wafer according to the double-sided grinding removal amount of the target wafer, including: the grinding and thinning device 300 performs double-sided grinding of the silicon surface and the carbon surface of the silicon carbide wafer at the same time according to the double-sided grinding removal amount of the target wafer.

[0066] In summary, the embodiments of the present application provide a processing method and a processing system for controlling the surface shape of a large-sized silicon carbide substrate, the processing method comprising: cutting a silicon carbide crystal to obtain a silicon carbide wafer; determining a target wafer curvature of the silicon carbide wafer under a target wafer double-sided grinding removal amount condition based on a linear relationship between the wafer double-sided grinding removal amount and the wafer curvature, wherein the wafer double-sided grinding removal amount is the total removal amount of the silicon surface and the carbon surface of the silicon carbide wafer to be ground; under the condition that the target wafer curvature satisfies the set curvature, double-sided grinding the silicon carbide wafer according to the target wafer double-sided grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

[0067] As can be seen from the above content, the technical solution provided in the embodiment of the present application, before thinning the silicon carbide wafer, first analyzes the linear relationship between the amount of wafer double-sided grinding removal and the wafer curvature to obtain the target wafer curvature, and if the target wafer curvature meets expectations, the silicon carbide wafer is double-sided ground, and finally a silicon carbide substrate with the expected wafer curvature is obtained, achieving the processing purpose of controlling the surface shape of the silicon carbide substrate and improving the product yield. When the target wafer curvature does not meet expectations, there is no need to perform subsequent processing on the silicon carbide wafer, thereby saving materials and reducing the preparation cost of the silicon carbide substrate.

[0068] In the description of the embodiments of the present application, it needs to be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0069] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0070] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0071] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0072] In the embodiments of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0073] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A processing method for controlling the surface shape of a large-sized silicon carbide substrate, characterized in that: include: Cutting the silicon carbide crystal to obtain a silicon carbide wafer; Based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, determining the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition, wherein the wafer double-side grinding removal amount is the total removal amount of the silicon surface and the carbon surface of the silicon carbide wafer to be ground; Under the condition that the target wafer curvature meets the set curvature, the silicon carbide wafer is double-sided ground according to the target wafer double-sided grinding removal amount to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

2. The method for controlling the surface shape of a large-sized silicon carbide substrate according to claim 1, characterized in that: The method of determining the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-side grinding removal amount based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature comprises: Based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, the target wafer curvature of the silicon carbide wafer under the target wafer double-side grinding removal amount condition is determined, wherein the linear relationship between the wafer double-side grinding removal amount and the wafer curvature is: Y=AX+B; Y is the curvature of the wafer, X is the amount of wafer double-sided grinding removed, A is a constant determined based on a double-sided grinding machine and double-sided grinding process experiment, and B is the crystal convexity of the silicon carbide crystal.

3. The method for controlling the surface shape of a large-sized silicon carbide substrate according to claim 2, characterized in that: The constant A determined based on the double-sided grinding machine and double-sided grinding process experiment has a value range of -2 to 2; The value range of the crystal convexity B of the silicon carbide crystal is -5 to 8.

4. The method for controlling the surface shape of a large-sized silicon carbide substrate according to claim 1, characterized in that: The method of cutting the silicon carbide crystal to obtain the silicon carbide wafer comprises: The silicon carbide crystal is cut by a multi-wire cutting process to obtain a silicon carbide wafer.

5. The method for controlling the surface shape of a large-sized silicon carbide substrate according to claim 1, characterized in that: The double-sided grinding of the silicon carbide wafer according to the target wafer double-sided grinding removal amount comprises: The silicon surface and the carbon surface of the silicon carbide wafer are double-sided ground simultaneously according to the target wafer double-sided grinding removal amount.

6. A processing system for controlling the surface shape of a large-sized silicon carbide substrate, characterized in that: include: A cutting device, wherein the cutting device is used to cut the silicon carbide crystal to obtain a silicon carbide wafer; A host computer, wherein the host computer determines a target wafer curvature of the silicon carbide wafer under a target wafer double-side grinding removal amount condition based on a linear relationship between a wafer double-side grinding removal amount and a wafer curvature, wherein the wafer double-side grinding removal amount is a total removal amount of a silicon surface and a carbon surface of the silicon carbide wafer to be ground; A grinding and thinning device, when the target wafer curvature meets the set curvature condition, the grinding and thinning device performs double-sided grinding on the silicon carbide wafer according to the double-sided grinding removal amount of the target wafer to obtain a silicon carbide substrate whose wafer curvature meets the target surface shape.

7. The processing system for controlling the surface shape of a large-sized silicon carbide substrate according to claim 6, characterized in that: The host computer determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-side grinding removal amount based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, including: The host computer determines the target wafer curvature of the silicon carbide wafer under the condition of the target wafer double-side grinding removal amount based on the linear relationship between the wafer double-side grinding removal amount and the wafer curvature, wherein the linear relationship between the wafer double-side grinding removal amount and the wafer curvature is: Y=AX+B; Y is the curvature of the wafer, X is the amount of wafer double-sided grinding removed, A is a constant determined based on a double-sided grinding machine and double-sided grinding process experiment, and B is the crystal convexity of the silicon carbide crystal.

8. The processing system for controlling the surface shape of a large-sized silicon carbide substrate according to claim 7, characterized in that: The constant A determined based on the double-sided grinding machine and double-sided grinding process experiment has a value range of -2 to 2; The value range of the crystal convexity B of the silicon carbide crystal is -5 to 8.

9. The processing system for controlling the surface shape of a large-sized silicon carbide substrate according to claim 6, characterized in that: The cutting device is used to cut silicon carbide crystals to obtain silicon carbide wafers, and comprises: The cutting device adopts a multi-wire cutting process to cut silicon carbide crystals to obtain silicon carbide wafers.

10. The processing system for controlling the surface shape of a large-sized silicon carbide substrate according to claim 6, characterized in that: The grinding and thinning device performs double-side grinding on the silicon carbide wafer according to the target wafer double-side grinding removal amount, comprising: The grinding and thinning device simultaneously performs double-side grinding on the silicon surface and the carbon surface of the silicon carbide wafer according to the target wafer double-side grinding removal amount.

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