Bonding method for growing SiC crystals

Abstract

The invention relates to a bonding method for growing SiC crystals. The bonding method comprises the following steps: 1) spin coating of seed crystals; 2) baking the binder; (3) bonding the seed crystals; 4) hot-pressing, sintering and curing the binder; 5) spinning graphite paper; and 6) bonding, hot-pressing, sintering and curing. The method has the advantages that the method is reasonable in design, uniform thickness distribution and excellent bonding compactness of the adhesive layer between the seed crystal and the seed crystal support can be ensured, cracking of the seed crystal due to the action of non-uniform mechanical stress and thermal stress and crystal defects caused by back sublimation are avoided, meanwhile, the temperature gradient distribution of the seed crystal is uniform, and the quality of the seed crystal is improved. The uniform growth of the silicon carbide crystals is facilitated, and the quality and yield of the silicon carbide crystals are further improved.

Description

Technical Field

[0001] The invention relates to a SiC crystal growth method, in particular to a bonding method for growing high-quality SiC crystals. Background Art

[0002] With the rapid development of electronic and information technology, semiconductor technology innovation is becoming increasingly important. Wide bandgap semiconductor materials represented by silicon carbide (SiC) are the third generation of semiconductors after silicon (Si) and gallium arsenide (GaAs). Silicon carbide has the advantages of high breakdown field strength, high thermal conductivity, high saturated drift electron rate and high bonding energy. It has great potential in aerospace, information technology, new energy technology, national defense and security, and is one of the most promising core materials in the semiconductor field.

[0003] Silicon carbide crystals are usually grown using physical vapor transport (PVT), and the typical structure of the growth chamber is as follows: Figure 1 As shown. The silicon carbide raw material is placed in the lower part of the growth chamber, and the seed crystal is fixed on the top of the crucible. The part that fixes the seed crystal is usually called the seed crystal holder, and the seed crystal is bonded to the seed crystal holder by a binder. By controlling the temperature and pressure of the growth chamber, the silicon carbide raw material sublimates from the lower part of the crucible and rises to the seed crystal for accumulation and growth, and finally a silicon carbide single crystal is obtained.

[0004] The growth of silicon carbide crystals is a complex process of gas phase transport and crystallization, which is affected by many factors. Among them, the seed crystal fixing technology is the key factor affecting the crystal growth process and crystallization quality. Usually, the silicon carbide seed crystal is fixed on the seed crystal holder by using a binder.

[0005] Seed crystal bonding must first ensure that the seed crystal is stably fixed on the seed crystal holder to ensure that the seed crystal does not fall off during the crystal growth process under high temperature. In addition, the seed crystal bonding effect also has a great influence on the crystal quality. On the one hand, if the adhesive is not evenly applied, it is easy to cause uneven gaps between the seed crystal and the seed crystal holder, making the temperature of different regions of the seed crystal uneven, affecting the uniform growth of the crystal; on the other hand, after the adhesive is cured, mechanical stress will be generated on the seed crystal. The uniformity of the adhesive distribution directly affects the uniformity of the mechanical stress distribution in different regions of the seed crystal. At the same time, from room temperature to the crystal growth temperature, uneven thermal stress and mechanical stress can easily cause the seed crystal to deform, thereby affecting the crystal quality, and in severe cases, it is easy to cause the seed crystal to crack and break. There is also the density of seed crystal bonding. The density of seed crystal bonding affects the degree of sublimation on the back of the seed crystal. The back sublimation of the seed crystal will cause the seed crystal to be destroyed and introduce a large number of micropipe defects in the crystal. To inhibit the back sublimation of the seed crystal, it is necessary to keep a uniform and small gap between the seed crystal and the seed crystal holder.

[0006] The bonding, fixing and protection of seed crystals have a significant impact on the growth of silicon carbide crystals. The seed crystal bonding and fixing method is a key technology for the growth of silicon carbide crystals, and is also closely related to seed crystal protection, which directly affects the quality of the crystal. In the existing technology, the bonding and fixing technology of silicon carbide seed crystals still needs to be improved. Solving the problem of seed crystal bonding and fixing is very important for growing high-quality silicon carbide crystals. Summary of the invention

[0007] The present invention provides a bonding method for growing SiC crystals, which aims to solve the problem of seed crystal bonding and fixing in the physical vapor transport method for growing silicon carbide crystals in the prior art, and to achieve uniform bonding and fixing of silicon carbide seed crystals.

[0008] The technical solution of the present invention is a bonding method for growing SiC crystals, comprising the following steps:

[0009] 1) Seed crystal spin coating;

[0010] 2) Binder baking;

[0011] 3) Seed crystal bonding;

[0012] 4) hot pressing and sintering of the binder;

[0013] 5) Graphite paper spin coating;

[0014] 6) Bonding, hot pressing, sintering and curing.

[0015] The seed crystal on which the adhesive is spin-coated is baked, so that the solvent in the adhesive can be fully volatilized, the generation of bubbles can be reduced, the density of the bonding can be improved, the occurrence of back sublimation of the seed crystal can be reduced, and the yield rate of the crystal can be improved.

[0016] Preferably, the adhesive includes phenolic resin glue, AB glue or photoresist. Different adhesives can be combined with different spin coating processes, which are specifically set according to the viscosity, curing temperature, effective thickness and other conditions of the adhesive, so that the adhesive's own advantages can be fully utilized, so that different adhesives can achieve the same bonding effect, providing space for the selection of adhesives.

[0017] Preferably, the step 1) includes cleaning the seed crystal holder, graphite paper and silicon carbide seed crystal, placing the cleaned silicon carbide seed crystal Si face up and centered on the spin coater suction cup, dropping the adhesive on the silicon carbide seed crystal, and then starting spin coating to obtain a silicon carbide seed crystal with a uniform adhesive coated thereon.

[0018] Preferably, in the step 1), the seed crystal holder, graphite paper and seed crystal are preheated using a heating platform before spin coating, and the order of placement from bottom to top is seed crystal holder, graphite paper, seed crystal. This can effectively improve the adhesion of the adhesive, and make the bonding stronger when the same adhesive is used.

[0019] Preferably, the step 2) comprises placing the seed crystal holder, graphite paper and silicon carbide seed crystal Si obtained in step 1) with the surface facing upwards concentrically from bottom to top in the center of the heating platform for low-temperature baking.

[0020] Preferably, the step 3) includes picking up the silicon carbide seed crystal obtained in step 2), and tightly bonding it with the Si side facing downward on the graphite paper placed in step 2), the adhesive is located between the seed crystal and the graphite paper, the seed crystal and the graphite paper are concentric, and the gaps between the seed crystal and the graphite paper and between the graphite paper and the seed crystal holder are uniform.

[0021] Preferably, in the step 3), when the silicon carbide seed crystal Si is tightly bonded face-down on the graphite paper placed in step 2), a silicone rubber roller is used to uniformly apply pressure to the seed crystal and the graphite paper so that the seed crystal and the graphite paper are tightly bonded. The use of a silicone rubber roller can make the seed crystal, the adhesive and the graphite paper fit more evenly and firmly without crushing the graphite paper and the seed crystal, eliminate the risk of cracking of the seed crystal due to thermal stress and mechanical stress, and improve the advantages of the crystal growth surface.

[0022] Preferably, the step 4) comprises subjecting the adhesive for bonding the seed crystal and the graphite paper obtained in step 3) to a hot pressing sintering and curing treatment.

[0023] Preferably, the step 5) includes placing the hot-pressed sintered and solidified seed crystal graphite paper obtained in step 4) on the spin coater suction cup with the center facing up, dripping the binder into the center of the graphite paper, and then starting the spin coating to obtain the graphite paper with the binder evenly coated.

[0024] Preferably, the step 6) comprises closely bonding the graphite paper with the seed crystals evenly spin-coated in step 5) to the seed crystal holder, and performing a hot pressing sintering and curing treatment.

[0025] Preferably, the steps 4) and 6) are cured by segmented hot pressing sintering, including segmented gradual heating and segmented gradual cooling. The segmented gradual heating can effectively squeeze out the solvent that has not been completely volatilized in the early baking of the binder, reduce bonding bubbles, and improve bonding density. The segmented gradual cooling can improve the bonding layer problem caused by thermal stress between the seed crystal, the binder, the graphite paper and the seed crystal holder, and improve the density and firmness.

[0026] The advantages of the present invention are as follows: the method is reasonably designed, which can ensure that the thickness of the adhesive layer between the seed crystal and the seed crystal holder is evenly distributed and the bonding density is excellent, thereby avoiding the cracking of the seed crystal due to uneven mechanical stress and thermal stress, as well as crystal defects caused by back sublimation. At the same time, the temperature gradient of the seed crystal is evenly distributed, which is conducive to the uniform growth of silicon carbide crystals and further improves the quality and yield rate of silicon carbide crystals. Specifically,

[0027] 1) Preheating the seed crystal holder, graphite paper, and seed crystal first can effectively improve the adhesion of the adhesive compared to the prior art, and make the bonding stronger when the same adhesive is used;

[0028] 2) Baking the seed crystals that have been spin-coated with the adhesive can fully volatilize the solvent in the adhesive. Compared with the existing bonding hot pressing curing method, it can greatly reduce the generation of bubbles, improve the density of the bond, reduce the occurrence of seed crystal back sublimation, and improve the yield of the crystal. It is also preferred to use a silicone rubber roller, which can make the seed crystal, adhesive and graphite paper fit more evenly and firmly without crushing the graphite paper and seed crystal. Compared with the existing bonding method, it can eliminate the risk of cracking of the seed crystal due to thermal stress and mechanical stress, and improve the advantage of the crystal growth surface shape;

[0029] 3) Different adhesives can be combined with different spin coating processes, which can be set according to the viscosity, curing temperature, effective thickness and other conditions of the adhesive, so as to give full play to the advantages of the adhesive itself, so that different adhesives can achieve the same bonding effect, providing space for the selection of adhesives;

[0030] 4) Use segmented hot pressing sintering curing, gradually increase and decrease the temperature in segments, where the segmented gradual increase in temperature can effectively squeeze out the solvent that has not been completely volatilized in the early baking of the binder, reduce bonding bubbles, and improve bonding density. Gradually cooling can improve the bonding layer problem caused by thermal stress between the seed crystal, binder, graphite paper and seed crystal holder, and improve density and firmness;

[0031] 5) This method is simple and convenient to implement, and the bonding success rate is close to 100%. Compared with the prior art seed crystal bonding and fixing, it does not require rework, can reduce material costs, improve bonding quality, and improve crystal quality and yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the typical structure of a growth chamber for growing silicon carbide crystals using the physical vapor transport method.

[0033] Figure 2 It is a schematic diagram of the baking of the adhesive in the bonding method for growing SiC crystals of the present invention.

[0034] Figure 3 It is a schematic diagram of seed crystal bonding in the bonding method for growing SiC crystals of the present invention.

[0035] Figure 4 The figure is a schematic diagram of an embodiment of a hot pressing and sintering solidification tooling used for hot pressing and sintering solidification of a binder in the bonding method for growing SiC crystals of the present invention.

[0036] Figure 5 yes Figure 4 A schematic diagram of an embodiment of a hot pressing furnace into which a press sintering and curing tool is placed. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to examples and specific implementation modes.

[0038] A bonding method for growing SiC crystals, comprising the following steps:

[0039] 1) Spin coating of seed crystal: Clean the seed crystal holder, graphite paper and silicon carbide seed crystal as necessary, place the cleaned silicon carbide seed crystal Si side up and in the center on the spin coater suction cup, drop a proper amount of adhesive on the silicon carbide seed crystal, and then start spin coating to obtain a silicon carbide seed crystal with a uniform adhesive coated on it.

[0040] 2) Binder baking: Place the seed crystal holder, graphite paper, and silicon carbide seed crystal obtained in step 1) with the Si surface facing upwards in the center of the heating platform from bottom to top and bake at low temperature. Figure 2 shown.

[0041] 3) Seed crystal bonding: Pick up the silicon carbide seed crystal obtained in step 2), and bond it tightly with the Si surface facing downward on the graphite paper placed in step 2), wherein the adhesive is located between the seed crystal and the graphite paper, the seed crystal and the graphite paper are concentric, and the gap between the seed crystal and the graphite paper is uniform, and the gap between the graphite paper and the seed crystal holder is uniform, such as Figure 3 shown.

[0042] 4) Hot-pressing and sintering the binder: The binder for bonding the seed crystal and the graphite paper obtained in step 3) is subjected to hot-pressing and sintering curing treatment.

[0043] 5) Spin coating of graphite paper: Place the hot-pressed, sintered and solidified seed crystal graphite paper obtained in step 4) on the spin coater suction cup with the center facing up, drop a proper amount of adhesive in the center of the graphite paper, and then start spin coating to obtain graphite paper with evenly coated adhesive.

[0044] 6) Bonding, hot pressing, sintering and curing: The graphite paper with the seed crystal evenly spin-coated obtained in step 5) is tightly bonded to the seed crystal holder, and hot pressing, sintering and curing treatment is performed.

[0045] Spin coating process: Specifically, the cleaned silicon carbide seed crystal is placed in the center on the spin coater suction cup, and the adhesive is dripped on the center of the silicon carbide seed crystal with a disposable dropper. The amount of adhesive dripped is determined according to the size of the seed crystal. At the same time, the stability of the spin coating process can ensure the thickness and uniformity of the adhesive spin coating. By adopting different spin coating processes, the thickness of the spin coating adhesive can be adjusted.

[0046] Seed crystal bonding: specifically, using a spin coater to spin-coat silicon carbide with an adhesive to bond the seed crystal to graphite paper without an adhesive, or spin-coating the adhesive on the graphite paper on the back of the seed crystal that has been heat-pressed and cured, and bonding it to a seed crystal holder that is not coated with an adhesive, wherein the diameter of the seed crystal holder is the same as or slightly larger than the diameter of the seed crystal and the graphite paper, the diameter of the graphite paper is the same as or slightly larger than the diameter of the seed crystal, and the crystal continues to grow on the seed crystal.

[0047] Hot pressing sintering and curing: specifically, pressure is applied on the seed crystal bonded with the binder to perform high-temperature sintering treatment, and the sintering and curing is carried out by step-by-step heating.

[0048] In step 1), the binder is preferably any common binder such as phenolic resin glue, AB glue or photoresist. After curing, it can be used in a high temperature environment of up to 3000°C for growing silicon carbide crystals by PVT method. In order to make the binder meet the requirements of spin coating process, a heating platform can be used to properly heat the seed crystal holder, graphite paper, seed crystal and binder so that the binder maintains a certain fluidity and is easy to spin coat.

[0049] In step 2), the baking temperature of the binder is preferably 60-200°C, and the baking time is preferably 0.5-2h. When AB glue is used as a binder, its baking temperature is preferably 60-150°C, and the baking time is preferably 0.5-1h; the baking temperature of phenolic resin glue and photoresist is preferably 60-100°C, and the baking time is preferably 1-2h.

[0050] In step 4) and step 6), the curing temperature of the hot pressing sintering of the binder is preferably 200-800°C, and the curing time is preferably 3-12 hours. Among them, when AB glue is used as a binder, its hot pressing sintering curing temperature is preferably 200-400°C, and the curing time is preferably 3-5 hours; the hot pressing sintering curing temperature of phenolic resin glue and photoresist is preferably 400-800°C, and the curing time is preferably 4-12 hours.

[0051] The optimal hot pressing sintering curing temperature of the binder is preferably 200-600°C, and the curing time is preferably 4-8h.

[0052] According to the above steps, the seed crystal bonding method for growing high-quality silicon carbide crystals includes: a specific adhesive curing treatment process, using a spin coater method to evenly spin coat the adhesive, and after the seed crystal and the seed crystal holder are tightly bonded, necessary post-treatment is performed according to the characteristics of different adhesives to fully cure the adhesive and achieve good bonding between the seed crystal and the seed crystal holder. Among them, the heat treatment curing process of the adhesive used is an important part of the seed crystal bonding method, and the appropriate curing temperature and curing time can be selected according to the characteristics of the adhesive and the instructions for use attached to the adhesive. The following describes the different technical parameters corresponding to the use of different adhesives in combination with 4 embodiments.

[0053] Example 1: Adhesive using AB glue

[0054] A bonding method for growing SiC crystals comprises the following steps:

[0055] 1) Level, process and clean the seed crystal holder and graphite paper as necessary, clean the seed crystal as necessary, and preheat the seed crystal holder, graphite paper and seed crystal using a heating platform (the order of placement from bottom to top is seed crystal holder, graphite paper, seed crystal, such as Figure 2 ), heat to 80℃ and turn off the heating platform to remove moisture attached to the surface of the seed crystal holder, graphite paper and seed crystal due to the environment.

[0056] 2) Place the treated seed crystal in the center on the spin coater suction cup, use a syringe to drop 5 ml of AB glue, cover the spin coater lid, and use a two-stage mode for spin coating. The first period is 20 seconds, the speed is 3000 r / min, and the second period is 20 seconds, the speed is 6000 r / min. This speed can ensure that the AB glue is evenly distributed on the Si surface of the seed crystal.

[0057] 3) Place the spin-coated seed crystal on the heating platform of step 1), place it on the graphite paper with the Si side facing up, and bake it at 110°C for 30 minutes. Then, place the seed crystal Si side facing down and tightly bonded to the graphite paper below the seed crystal, and use a silicone rubber roller to evenly apply appropriate pressure to the seed crystal and graphite paper to make the seed crystal and graphite paper tightly bonded.

[0058] 4) Place the bonded seed crystal and graphite paper in a hot press furnace using a tooling clamp (hot press sintering and curing tooling such as Figure 4 ), the binder is subjected to hot pressing sintering and curing treatment, the curing temperature is 300°C, the curing time is 4 hours, and a seed crystal with a good bonding is obtained.

[0059] 5) Place the bonded seed crystal with its C side facing down on the spin coater suction cup, add 5 ml of AB glue using a syringe, cover the spin coater lid, and use a two-stage mode for spin coating. The first stage is 20 seconds at a speed of 3000 r / min, and the second stage is 20 seconds at a speed of 5000 r / min. This speed can ensure that the AB glue is evenly distributed on the graphite paper on the S i side of the seed crystal.

[0060] 6) Place the spin-coated seed crystal graphite paper obtained in step 5) face down and stick it tightly in the center on the seed crystal holder (such as Figure 4 ), use a silicone rubber roller to evenly apply appropriate pressure to the seed crystal so that the graphite paper on the Si surface of the seed crystal is tightly bonded to the seed crystal holder.

[0061] 7) Place the bonded seed crystal and seed crystal holder in a hot pressing furnace using a tooling clamp (the hot pressing sintering tooling is placed in the furnace as shown in the figure). Figure 5 ), the binder is subjected to hot pressing and sintering curing treatment, the curing temperature is 300° C., and the curing time is 4 hours to obtain a well-bonded seed crystal.

[0062] Example 2: Adhesive using diluted AB glue

[0063] A bonding method for growing SiC crystals, steps 1), 3), 4), 6), and 7) are the same as those in Example 1, and the other steps are as follows:

[0064] 2) Place the treated seed crystal in the center on the spin coater suction cup, use a disposable dropper to drop 5 ml of diluted AB glue (AB glue and anhydrous ethanol are diluted in a mass ratio of about 1:1, and the viscosity after dilution is 20-22 mPa·s), cover the spin coater lid, and the spin coater uses a five-stage mode for spin coating. The first period is 10 s, the speed is 500 r / min, the second period is 10 s, the speed is 2000 r / min, the third period is 20 s, the speed is 5000 r / min, the fourth period is 10 s, the speed is 2000 r / min, and the fifth period is 10 s, the speed is 1000 r / min. This speed can ensure that the diluted AB glue is evenly distributed on the Si surface of the seed crystal.

[0065] 5) Place the bonded seed crystal with its C side facing down in the center on the spin coater suction cup, add 5 ml of diluted AB glue using a disposable dropper, cover the spin coater lid, and use a two-stage mode for spin coating. The first stage is 10 s at a speed of 1500 r / min, and the second stage is 20 s at a speed of 2500 r / min. This speed can ensure that the diluted AB glue is evenly distributed on the graphite paper on the S i side of the seed crystal.

[0066] Embodiment 3: Adhesive using photoresist

[0067] A bonding method for growing SiC crystals, steps 1) and 6) are the same as those in Example 1, and the other steps are as follows:

[0068] 2) Place the treated seed crystal in the center on the spin coater suction cup, use a disposable dropper to drop 2.5 ml of photoresist, cover the spin coater lid, and use a two-stage mode for spin coating. The first period is 5s, the speed is 1500r / min, and the second period is 20s, the speed is 2500r / min. This speed can ensure that the photoresist is evenly distributed on the Si surface of the seed crystal.

[0069] 3) Place the spin-coated seed crystal on the heating platform of step 1), place it on the graphite paper with the Si side facing up, and bake it at 60°C for 1 hour. Then, tightly bond the seed crystal Si side facing down to the graphite paper below the seed crystal, and use a silicone rubber roller to evenly apply appropriate pressure to the seed crystal and graphite paper to make the seed crystal and graphite paper tightly bonded.

[0070] 4) The bonded seed crystal and graphite paper are placed in a hot pressing furnace by clamping with a tool, and the adhesive is subjected to hot pressing, sintering and curing treatment. The curing temperature is 600° C. and the curing time is 8 hours to obtain a seed crystal that is bonded once.

[0071] 5) Place the once bonded seed crystal with its C side facing down in the center on the spin coater suction cup, use a disposable dropper to drop 3 ml of photoresist, cover the spin coater lid, and use a two-stage mode for spin coating. The first stage is 5 s at a speed of 2000 r / min, and the second stage is 20 s at a speed of 2500 r / min. This speed can ensure that the photoresist is evenly distributed on the graphite paper on the S i side of the seed crystal.

[0072] 7) The bonded seed crystal and seed crystal holder are clamped by a tool and placed in a hot pressing furnace to perform hot pressing sintering and curing treatment on the adhesive. The curing temperature is 600° C. and the curing time is 8 hours to obtain a bonded seed crystal.

[0073] Example 4: Phenolic resin adhesive is used as the adhesive

[0074] A bonding method for growing SiC crystals, steps 1), 3), 4), 6), and 7) are the same as those in Example 3, and the other steps are as follows:

[0075] 2) Place the treated seed crystal in the center on the spin coater suction cup, use a disposable dropper to drop 3 ml of phenolic resin glue, cover the spin coater lid, and use a two-stage mode for spin coating. The first period is 10 s, the speed is 2000 r / min, and the second period is 20 s, the speed is 3000 r / min. This speed can ensure that the phenolic resin glue is evenly distributed on the Si surface of the seed crystal.

[0076] 5) Place the once bonded seed crystal with its C surface facing down in the center on the spin coater suction cup, use a disposable dropper to drop 3 ml of phenolic resin glue, cover the spin coater lid, and use a two-stage mode for spin coating. The first period is 10 s at a speed of 2000 r / min, and the second period is 20 s at a speed of 2500 r / min. This speed can ensure that the phenolic resin glue is evenly distributed on the graphite paper on the S i surface of the seed crystal.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A bonding method for growing SiC crystals, characterized in that: The steps include: 1) Seed crystal spin coating; 2) Binder baking; 3) Seed crystal bonding; 4) hot pressing and sintering of the binder; 5) Graphite paper spin coating; 6) Bonding, hot pressing, sintering and curing; The adhesive includes phenolic resin glue, AB glue or photoresist.

2. A method for bonding a growing SiC crystal according to claim 1, characterized in that: The step 1) includes cleaning the seed crystal holder, graphite paper and silicon carbide seed crystal, placing the cleaned silicon carbide seed crystal with Si surface facing up and centered on the spin coater suction cup, dropping the adhesive on the silicon carbide seed crystal, and then starting spin coating to obtain the silicon carbide seed crystal with the adhesive evenly coated.

3. A method for bonding a growing SiC crystal as claimed in claim 2, characterized in that: In the step 1), the seed crystal holder, graphite paper and seed crystal are preheated using a heating platform before spin coating, and the order of placement from bottom to top is seed crystal holder, graphite paper, seed crystal.

4. A method for bonding a growing SiC crystal as claimed in claim 3, characterized in that: The step 2) includes placing the seed crystal holder, graphite paper and silicon carbide seed crystal obtained in step 1) with the Si surface facing upwards in the center of the heating platform from bottom to top and performing low-temperature baking.

5. A method for bonding a growing SiC crystal as claimed in claim 4, characterized in that: The step 3) includes picking up the silicon carbide seed crystal obtained in step 2), and tightly bonding it with the Si surface facing downward on the graphite paper placed in step 2), the adhesive is located between the seed crystal and the graphite paper, the seed crystal and the graphite paper are concentric, and the gaps between the seed crystal and the graphite paper and between the graphite paper and the seed crystal holder are uniform.

6. A method for bonding a growing SiC crystal as claimed in claim 5, characterized in that: In the step 3), when the silicon carbide seed crystal Si face downwards and is tightly bonded to the graphite paper placed in step 2), a silicone rubber roller is used to evenly apply pressure to the seed crystal and the graphite paper to make the seed crystal and the graphite paper tightly bonded.

7. A method for bonding a growing SiC crystal according to claim 6, characterized in that: The step 4) includes subjecting the adhesive for bonding the seed crystal and the graphite paper obtained in step 3) to hot pressing, sintering and curing treatment.

8. A method for bonding a growing SiC crystal as claimed in claim 7, characterized in that: The step 5) includes placing the hot-pressed sintered and solidified seed crystal graphite paper obtained in step 4) on the spin coater suction cup with the center facing upward, dripping the binder into the center of the graphite paper, and then starting the spin coating to obtain the graphite paper with the binder evenly coated.

9. A method for bonding a growing SiC crystal according to claim 8, characterized in that: The step 6) comprises closely bonding the graphite paper with the seed crystals evenly spin-coated in step 5) on the seed crystal holder, and performing hot pressing sintering and curing treatment.

10. A method for bonding a growing SiC crystal according to claim 9, characterized in that: The steps 4) and 6) are solidified by segmented hot pressing sintering, including segmented gradual heating and segmented gradual cooling.

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