A method for improving heat dissipation performance of wafer

Abstract

An embodiment of the present invention provides a method for improving wafer heat dissipation performance, comprising: cleaning a silicon carbide substrate; sequentially performing a plasma etching process, a nanodiamond seeding process, a diamond nucleation process, and a diamond epitaxial growth process on the back side of the silicon carbide substrate to obtain a diamond-based silicon carbide wafer; and performing a high-temperature annealing process on the diamond-based silicon carbide wafer. In this technical solution, type IIa diamond, which has improved thermal conductivity, cleavage, and semiconductor properties, is combined with a silicon carbide substrate to form a diamond-based SiC wafer. The excellent thermal conductivity of diamond is utilized to improve wafer heat dissipation. Heat conducting wires are provided on the bonded wafers to conduct localized heat away from the bonding portion, thereby extending the service life of the semiconductor device.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer manufacturing, and in particular to a method for improving the heat dissipation performance of a wafer. Background Art

[0002] Silicon carbide (SiC), a third-generation semiconductor material, belongs to the wide-bandgap (WBG) family of materials. It boasts advantages such as a high breakdown electric field, high thermal conductivity, high electron saturation velocity, and strong radiation resistance. Therefore, semiconductor devices made with this third-generation semiconductor material not only operate stably at higher temperatures, making them suitable for high-voltage and high-frequency applications, but also achieve higher operating capabilities with less power consumption.

[0003] In the process of implementing the present invention, the inventors discovered that the prior art has at least the following problems:

[0004] Both SiC power devices and GaN power devices based on SiC face the risk of performance degradation or even complete failure due to "self-heating" at high power output. Therefore, how to improve the heat dissipation performance of silicon carbide semiconductors to avoid or reduce the performance degradation or damage caused by "self-heating" is a problem that needs to be solved. Summary of the Invention

[0005] An embodiment of the present invention provides a method for improving the heat dissipation performance of a wafer, so as to solve the problem of performance degradation or damage of silicon carbide semiconductor devices caused by the "self-heating effect" in the prior art.

[0006] To achieve the above-mentioned objectives, an embodiment of the present invention provides a method for improving the heat dissipation performance of a wafer, comprising: cleaning a silicon carbide substrate; sequentially performing a plasma etching process, a nanodiamond seeding process, a diamond nucleation process, and a diamond epitaxial growth process on the back side of the silicon carbide substrate to obtain a diamond-based silicon carbide wafer; and performing a high-temperature annealing process on the diamond-based silicon carbide wafer.

[0007] The above technical solution has the following beneficial effects:

[0008] This technical solution combines type IIa diamond, which boasts superior thermal conductivity, cleavage, and semiconductor properties, with a silicon carbide substrate to form a diamond-based SiC wafer. Diamond's excellent thermal conductivity is leveraged to improve heat dissipation, resulting in superior heat dissipation performance. This can increase the output power and frequency of semiconductor devices during subsequent use, while also reducing the risk of performance degradation or damage, thereby extending their lifespan.

[0009] In addition, in the present application, a heat conducting wire is provided on one side or both sides of the bonding wafer. One end of the heat conducting wire is connected to the circuit area of the bonding wafer or is located near the circuit area, and the other end extends to the outside of the bonding wafer. The local accumulated heat of the bonding part is conducted out through the heat conducting wire, thereby achieving a good heat dissipation effect, extending the life of the device, and avoiding damage caused by the bonding part working under high temperature conditions for a long time, thereby ensuring the performance and stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0011] Figure 1 This is a flow chart of a method for improving wafer heat dissipation performance according to an embodiment of the present invention;

[0012] Figure 2 Schematic diagram of substrate cleaning in an embodiment of the present invention;

[0013] Figure 3 is a schematic diagram of a substrate after cleaning is completed in an embodiment of the present invention;

[0014] Figure 4 is a schematic diagram after plasma etching processing is completed in an embodiment of the present invention;

[0015] Figure 5 This is a schematic diagram of the nanodiamond after seeding in an embodiment of the present invention;

[0016] Figure 6 Schematic diagram of diamond nucleation after completion of the embodiment of the present invention;

[0017] Figure 7 Schematic diagram of the diamond outer edge after growth is completed in an embodiment of the present invention;

[0018] Figure 8 is a schematic diagram of setting a heat conducting wire in an embodiment of the present invention;

[0019] Figure 9 Schematic diagram of a spiral heat conducting wire in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, the present invention provides a method for improving the heat dissipation performance of a wafer, characterized by comprising:

[0022] S101, cleaning the silicon carbide substrate;

[0023] On the back side of the silicon carbide substrate,

[0024] S102, plasma etching process,

[0025] S103, nano-diamond seeding process,

[0026] S104, diamond nucleation process, and

[0027] S105, diamond epitaxial growth step, obtaining a diamond-based silicon carbide wafer;

[0028] S106: Perform high-temperature annealing on the diamond-based silicon carbide wafer.

[0029] To solve the aforementioned problems, in this application, silicon carbide wafers are combined with diamonds.

[0030] Diamond is the material with the highest thermal conductivity in nature and is a very good thermal conductor. Its thermal conductivity varies, but is generally 138.16W / (m·K). Type IIa diamond has particularly good thermal conductivity, which is 25 times that of copper at liquid nitrogen temperature and up to 2000W / (m·K) at room temperature, which is 5 times that of copper. It has super thermal conductivity and is an excellent substrate material for high-power density electronic device packaging. Diamond can be divided into two types: type I diamond and type II diamond according to the trace elements it contains. Type II diamond has better thermal conductivity, cleavage and semiconductor properties, and is mostly used in space technology and cutting-edge industries.

[0031] Therefore, in this application, when preparing the wafer, the diamond-based SiC wafer formed by combining SiC with IIa diamond can significantly improve the heat dissipation capacity of the SiC bottom layer, thereby increasing the output power and frequency of the SiC device and extending its service life.

[0032] Furthermore, the method for improving the heat dissipation performance of the wafer further includes:

[0033] S107, setting a heat conducting wire on the diamond-based silicon carbide wafer in a bonding manner.

[0034] Although IIa diamond can significantly improve heat dissipation, the part where IIa diamond and SiC are bonded will easily accumulate heat and may cause delamination of the bonded part. For this reason, in this application, a heat conducting wire is also provided on one side or both sides of the bonded wafer, so that one end of the heat conducting wire is connected to the circuit area of the bonded wafer or is located near the circuit area, and the other end extends to the outside of the bonded wafer, thereby reducing local heat accumulation in the bonded part. When the bonded device is working, the heat inside the device is conducted out through the heat conducting wire, thereby achieving a good heat dissipation effect and extending the life of the device; at the same time, damage caused by the bonding part working under high temperature conditions for a long time is avoided, thereby ensuring the performance and stability of the device.

[0035] Further, such as Figure 2 As shown, the step S101 specifically includes:

[0036] S1011. Circulatingly flushing the silicon carbide substrate with acetone and isopropyl alcohol to minimize residual impurities.

[0037] S1012, performing ultrasonic cleaning on the silicon carbide substrate in an acetone solution;

[0038] S1013, performing ultrasonic cleaning on the silicon carbide substrate in an alcohol solution;

[0039] S1014, air-drying the silicon carbide substrate.

[0040] The cleaning process utilizes two acetone and isopropyl alcohol steps, creating a "circular flushing" mode (acetone container I → acetone container II → isopropyl alcohol container I → isopropyl alcohol container II). This helps reduce solvent consumption. Ultrasonic cleaning is then employed, utilizing the direct and indirect effects of ultrasound on the liquid and dirt, including cavitation, acceleration, and forward flow, to disperse, emulsify, and exfoliate the dirt layer, achieving the cleaning objective.

[0041] The cleaned silicon carbide substrate is as follows Figure 3 shown.

[0042] Furthermore, the step S102 specifically includes:

[0043] S1021, placing the silicon carbide substrate into a plasma chemical vapor deposition system;

[0044] S1022, adjusting the temperature of the silicon carbide substrate to 100° C. to 300° C. higher than the diamond nucleation temperature;

[0045] S1023, introducing hydrogen or a first mixed gas into the plasma chemical vapor deposition system, where the first mixed gas consists of hydrogen and helium;

[0046] S1024: Perform plasma etching on the back side of the silicon carbide substrate by at least one of the following methods:

[0047] There are capacitively coupled plasma (CCP) treatment, inductively coupled plasma (ICP) treatment, and microwave plasma (ECR) treatment.

[0048] Plasma etching treatment can increase the roughness of the silicon carbide substrate surface, which is beneficial to subsequent diamond growth.

[0049] The silicon carbide substrate after plasma etching is as follows Figure 4 shown.

[0050] Furthermore, the step S103 specifically includes:

[0051] S1031, preparing a diamond nanoparticle suspension by mixing 0.1% to 15% of nanodiamond, 50% to 80% of a solvent, 2% to 8% of a surfactant, 8% to 25% of an organic anti-settling agent, and 6% to 30% of a dispersant, and then dispersing the mixture by ultrasonication to form a modified nanodiamond suspension;

[0052] S1032, immersing the silicon carbide substrate after the plasma etching treatment into a diamond nanoparticle suspension;

[0053] S1033, perform self-organized adsorption seeding, or perform ultrasonic adsorption seeding.

[0054] In the diamond nanoparticle suspension, the solvent is water or ethanol; the surfactant is two or three of nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether ammonium sulfate, and linear alkylbenzene sulfonate sodium; the organic anti-settling agent is two or three of acetic acid, alkane, and ethyl acetate; and the dispersant is two or three of triethylhexyl phosphate, methyl amyl alcohol, and fatty acid polyethylene glycol ester.

[0055] Nanodiamond particle seeding relies on surface chemical potential differences and the surface self-adsorption dipole effect for self-adsorption seeding. In addition to directly immersing the silicon carbide substrate in a diamond nanoparticle suspension, nanodiamond particle seeding can also be performed using ultrasonic enhancement treatment.

[0056] The silicon carbide substrate for nanodiamond seeding is as follows Figure 5 shown.

[0057] Furthermore, the step S104 specifically includes:

[0058] S1041, placing the silicon carbide substrate in the plasma chemical vapor deposition system;

[0059] S1042, introducing a second mixed gas into the plasma chemical vapor deposition system, where the second mixed gas consists of hydrogen and methane;

[0060] S1043, adjusting the methane content in the second mixed gas to 6% to 12%;

[0061] S1044, adjusting the temperature of the silicon carbide substrate to the diamond nucleation temperature (about 750° C.);

[0062] S1045. Maintain the above state for 5 to 20 minutes to allow diamond nucleation.

[0063] Before the diamond nucleation growth process on the silicon carbide wafer, high temperature H and He plasma are first introduced to perform deep surface etching to reduce the surface silicon carbide, form Si dangling bonds, and remove the non-diamond phase on the surface of the adsorbed nano-diamond. Later, when the diamond nucleation growth is carried out on the outer surface where the nano-diamond particles have been seeded, it is necessary to lower the temperature and introduce a high concentration of methane to form a covalent connection of C-Si-C. The silicon carbide substrate on which the diamond nucleation is completed is as follows: Figure 6 shown.

[0064] Furthermore, the step S105 specifically includes:

[0065] S1051, adjusting the methane content in the second mixed gas to 4% to 6%;

[0066] S1052, cooling the silicon carbide substrate to a temperature 50° C. lower than the diamond nucleation temperature (i.e., about 700° C.), at which point diamond epitaxial growth begins;

[0067] S1053: Maintain the above state until the diamond layer on the back side of the silicon carbide substrate grows to a desired value (for example, the thickness of the diamond layer reaches a desired thickness). At this point, the diamond epitaxial growth process is completed.

[0068] After the diamond epitaxial growth is completed, the following is obtained: Figure 7 The resulting diamond-based silicon carbide wafer is shown.

[0069] Furthermore, the step S106 specifically includes:

[0070] S1061. When the temperature of the diamond-based silicon carbide wafer cools to 400° C., introducing a third mixed gas, wherein the third mixed gas includes hydrogen and nitrogen;

[0071] S1062, heating the diamond-based silicon carbide wafer;

[0072] S1063, when the temperature of the diamond-based silicon carbide wafer reaches a preset annealing temperature, stopping heating and keeping the temperature constant;

[0073] S1064. Introduce argon and maintain for 5 to 10 minutes.

[0074] High-temperature annealing of the prepared diamond-based silicon carbide wafer eliminates quadrivacancy defects and restores conductivity. Preheating slows the formation of thermal donors during diamond growth, and as high-temperature annealing is completed, the suppression of thermal donors intensifies. High-temperature annealing uses nitrogen, hydrogen, a mixture of nitrogen and hydrogen, or air. Adding helium, neon, or argon to the annealing gas can further restore the crystal structure and eliminate defects.

[0075] After annealing is completed, a heat conducting wire can be set on the diamond-based silicon carbide wafer in a bonding manner. One end of the heat conducting wire is located in the area where heat is generated by the bonding part between the silicon carbide substrate and the type IIa diamond. The heat generating area is provided with a device structure that generates heat during operation. The heat conducting wire should be set adjacent to the silicon carbide or in contact with the silicon carbide; the other end extends to the outside of the diamond-based silicon carbide wafer to conduct the heat generated by the bonding part through the heat conducting wire. The silicon carbide contacted by the heat conducting wire is grounded through the heat conducting wire, and the heat conducting wire does not affect the normal operation of the subsequent finished device. In addition, the material of the heat conducting wire is one of aluminum, copper, silver, tungsten, tin, gold, tantalum, or a metal alloy material containing one or more of the above.

[0076] Furthermore, in step S107, a plurality of heat conducting wires are used; the inner ends of the heat conducting wires are fixedly connected to the diamond-based silicon carbide wafer, and the outer ends of the heat conducting wires extend in a direction away from the diamond-based silicon carbide wafer. In order to avoid accidental breakage of the connection between the heat conducting wire and the diamond-based silicon carbide wafer and thus affect the heat dissipation of the semiconductor device, the inner ends of the heat conducting wires can also be set as forked metal wires, for example, with two forks or three forks. The setting of the heat conducting wires is as follows: Figure 8 As shown in the figure, the thin lines on the outside of the diamond-based silicon carbide wafer are heat conducting wires, and the heat conducting wires are distributed in a curve, which can increase the length of the heat conducting wires within the effective space, thereby bringing better heat conduction and heat dissipation effects.

[0077] Furthermore, the method for improving the heat dissipation performance of the wafer further includes:

[0078] S108. Set up spiral heat conducting wires; wherein, the spiral heat conducting wires are arranged in a spiral manner in the plane outside the diamond-based silicon carbide wafer; the innermost circle of the spiral heat conducting wires is fixedly connected to the outer end of each heat conducting wire. The heat conducting wires are distributed in a spiral shape, which can increase the length of the heat conducting wires within the effective space, expand the heat dissipation area, and thus bring about better heat conduction and heat dissipation effects. The setting of the spiral heat conducting wires is as follows Figure 9 As shown in the figure, the thin line with one end connected to the diamond-based silicon carbide wafer represents the heat conduction line, and the line extending spirally to the outer layer is the spiral heat conduction line.

[0079] The method for improving the heat dissipation performance of a wafer according to the present invention is described below through two specific embodiments. Specific embodiment one:

[0081] S11. Select a 10×10 mm square silicon carbide (SiC) substrate, first clean it once with a two-step "circular exchange rinse" mode of acetone and isopropyl alcohol, then use acetone ultrasonic cleaning once for 10 minutes, then place it in an alcohol solution for further ultrasonic cleaning, and after the ultrasonication is completed, air-dry the SiC sample and place the air-dried SiC sample in a plasma CVD (chemical vapor deposition) device.

[0082] S12. ECR treatment (microwave plasma) is performed to etch the back side of the SiC using hydrogen and helium plasma in a hydrogen plasma environment to increase the roughness of the SiC surface. The treatment process settings are: the flow rate of the hydrogen and helium mixed gas (first mixed gas) is set to 300 sccm, hydrogen is 95%, helium is 5%, the microwave power is set to 3800 W, the chamber pressure is set to 8 kPa, the substrate temperature is about 800° C., and the etching time is 10 minutes.

[0083] S12. Prepare a nano-diamond suspension using diamond powder with a particle size of 30 nanometers, wherein the suspension comprises 10% nano-diamond, 54% solvent, 3% surfactant, 8% organic anti-settling agent, and 25% dispersant.

[0084] S14, immersing the SiC treated in step S12 into a nano-diamond suspension for seeding for 30 minutes, and relying on the chemical potential difference between the SiC sample and the nano-diamond powder surface, as well as the self-adsorption dipole effect on the sample surface, self-organized adsorption seeding is performed.

[0085] S15. The sample treated in step S14 is placed in the same apparatus as in step S12, and methane is introduced to form diamond nuclei on the SiC surface. The diamond nucleation process is set as follows: the hydrogen flow rate in the second mixed gas is set to 300 sccm, the methane concentration is set to 12%, the microwave power is set to 3800 W, the cavity pressure is set to 7.5 kPa, the substrate temperature is approximately 750° C., and diamond nucleation is started for 20 minutes.

[0086] S16. After nucleation is completed, the methane concentration is reduced and diamond growth begins. The diamond growth process is set as follows: the hydrogen flow rate in the second mixed gas is set to 300 sccm, the methane concentration is set to 4% (i.e., the proportion of methane in the second mixed gas is 4%), the microwave power is set to 3800 W, the cavity pressure is set to 7 kPa, and the substrate temperature is approximately 700°C.

[0087] S17. After the diamond growth is completed, the substrate temperature is lowered to 400°C and high-temperature annealing is started. The annealing process is set as follows: the flow rate of the nitrogen and hydrogen mixed gas (the third mixed gas) is set to 200 sccm, the substrate temperature is about 500°C; then argon is added with the gas flow rate unchanged, the temperature is raised to 550°C, and the annealing time is 5 minutes.

[0088] S18. A heat conducting wire is provided on the surface. The material of the heat conducting wire is metal. Preferably, the material of the heat conducting wire is silver. One end of the heat conducting wire is located in the area where the SiC wafer and the diamond substrate generate heat, and the other end extends to the outside of the SiC wafer and the diamond substrate so as to conduct the heat generated by the bonding part through the heat conducting wire. The heat conducting wire process is as follows: the heat conducting wire is distributed in a curve. Due to the use of a curved heat conducting wire, the length of the heat conducting wire can be increased within the effective space, thereby bringing about better heat conduction and heat dissipation effects. The arrangement of the heat conducting wire is as follows: Figure 8 shown.

[0089] Example 2

[0090] S21. Select a 15×15 mm square SiC substrate, first clean it once with a two-step "circular exchange flushing" mode of acetone and isopropanol, then use acetone ultrasonic cleaning once for 15 minutes, then place it in an alcohol solution for further ultrasonic cleaning, and after the ultrasonication is completed, air-dry the SiC sample and place the air-dried SiC sample in a plasma CVD (chemical vapor deposition) device.

[0091] S22. ECR treatment (microwave plasma) is performed in a hydrogen plasma environment to etch the back side of the SiC using hydrogen plasma to increase the roughness of the SiC surface. The treatment process settings are: hydrogen flow rate is set to 300 sccm, microwave power is set to 4000 W, chamber pressure is set to 8 kPa, substrate temperature is about 800°C, and etching time is 12 minutes.

[0092] S23. Prepare a nano-diamond suspension using diamond powder with a particle size of 30 nanometers, comprising 5% nano-diamonds, 60% solvent, 2% surfactant, 8% organic anti-settling agent, and 25% dispersant. Adjust the pH of the diamond suspension using acid and alkali to a pH between 6 and 10.

[0093] S24: Immerse the SiC treated in step S22 into a nano-diamond suspension for seeding. The ultrasonication time is 10 minutes, and the ultrasonic wave is used to enhance the adsorption of the SiC wafer, thereby adsorbing more nano-diamond particles.

[0094] S25. The sample processed in step S24 is placed in the same apparatus as in step S22, and methane is introduced to form diamond nuclei on the SiC surface. The diamond nucleation process is set as follows: the hydrogen flow rate in the second mixed gas is set to 300 sccm, the methane concentration is set to 12%, the microwave power is set to 4000 W, the cavity pressure is set to 7.5 kPa, the substrate temperature is approximately 750° C., and diamond nucleation is started for 15 minutes.

[0095] S26. After nucleation is complete, the methane concentration is reduced and diamond growth begins. The diamond growth process is set as follows: the hydrogen flow rate in the second mixed gas is set to 300 sccm, the methane concentration is set to 4%, the microwave power is set to 4000 W, the cavity pressure is set to 7 kPa, and the substrate temperature is about 700°C.

[0096] S27. After the diamond growth is completed, the substrate temperature is lowered to 400°C and high-temperature annealing is started. The annealing process is set as follows: the flow rate of the nitrogen and hydrogen mixed gas (the third mixed gas) is set to 200 sccm, the substrate temperature is about 600°C; argon is then added, the gas flow rate and temperature are kept constant, and the annealing time is 5 minutes.

[0097] S28. A heat conducting wire is provided on the surface. The material of the heat conducting wire is metal. Preferably, the material of the heat conducting wire is silver. One end of the heat conducting wire is located in the area where the SiC wafer and the diamond substrate generate heat, and the other end extends to the outside of the SiC wafer and the diamond substrate so as to conduct the heat generated by the bonding part through the heat conducting wire. The heat conducting wire process is as follows: the heat conducting wire is distributed in a spiral shape. Due to the use of the heat conducting wire with a spiral distribution, the length of the heat conducting wire can be increased within the effective space, the heat dissipation area can be expanded, and thus better heat conduction and heat dissipation effects can be achieved. The arrangement of the heat conducting wire is as follows: Figure 9 shown.

[0098] It should be understood that the specific order or hierarchy of steps in the disclosed processes is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0099] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention comprises less than all the features of any individual disclosed embodiment. The appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0100] The above description of the disclosed embodiments is intended to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments presented herein but is intended to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0101] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it will be appreciated by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including," as explained in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

[0102] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the heat dissipation performance of a wafer, characterized in that: include: performing substrate cleaning on a silicon carbide substrate; Plasma etching, nanodiamond seeding, diamond nucleation, and diamond epitaxial growth are sequentially performed on the back side of the silicon carbide substrate to obtain a diamond-based silicon carbide wafer. performing a high temperature annealing treatment on the diamond-based silicon carbide wafer; disposing a heat conducting wire on the diamond-based silicon carbide wafer in a bonding manner; There are multiple heat conducting wires; The inner end of the heat conducting wire is fixedly connected to the diamond-based silicon carbide wafer, and the outer end of the heat conducting wire extends in a direction away from the diamond-based silicon carbide wafer; A spiral heat conducting wire is provided; wherein, The spiral heat conductive wire is arranged in a spiral manner in a plane outside the diamond-based silicon carbide wafer; The innermost circle of the spiral heat-conducting wire is fixedly connected to the outer end of each heat-conducting wire; The high temperature annealing treatment of the diamond-based silicon carbide wafer specifically includes: When the temperature of the diamond-based silicon carbide wafer is cooled to 400° C., hydrogen, nitrogen, or a third mixed gas is introduced, wherein the third mixed gas includes hydrogen and nitrogen; heating the diamond-based silicon carbide wafer; When the temperature of the diamond-based silicon carbide wafer reaches a preset annealing temperature, heating is stopped and the temperature is kept constant; Let argon flow in for 5 to 10 minutes.

2. The method for improving the heat dissipation performance of a wafer according to claim 1, wherein: The cleaning of the silicon carbide substrate specifically includes: Circulatingly flushing the silicon carbide substrate with acetone and isopropyl alcohol; performing ultrasonic cleaning on the silicon carbide substrate in an acetone solution; performing ultrasonic cleaning on the silicon carbide substrate in an alcohol solution; The silicon carbide substrate is air-dried.

3. The method for improving the heat dissipation performance of a wafer according to claim 1, wherein: The plasma etching process specifically includes: placing the silicon carbide substrate into a plasma chemical vapor deposition system; Adjusting the temperature of the silicon carbide substrate to be 100° C. to 300° C. higher than the diamond nucleation temperature; introducing hydrogen or a first mixed gas into the plasma chemical vapor deposition system, wherein the first mixed gas consists of hydrogen and helium; The back side of the silicon carbide substrate is subjected to plasma etching treatment in at least one of the following ways: There are capacitively coupled plasma treatment, inductively coupled plasma treatment, or microwave plasma treatment.

4. The method for improving the heat dissipation performance of a wafer according to claim 3, wherein: The nanodiamond seeding process specifically includes: Prepare a diamond nanoparticle suspension, wherein the diamond nanoparticle suspension comprises the following components: 0.1% to 15% nanodiamond, 50% to 80% solvent, 2% to 8% surfactant, 8% to 25% organic anti-settling agent, and 6% to 30% dispersant; immersing the silicon carbide substrate in the diamond nanoparticle suspension; Self-organized adsorption seeding or ultrasonic adsorption seeding is performed.

5. The method for improving the heat dissipation performance of a wafer according to claim 4, wherein: The diamond nucleation process specifically includes: placing the silicon carbide substrate in the plasma chemical vapor deposition system; introducing a second mixed gas into the plasma chemical vapor deposition system, wherein the second mixed gas consists of hydrogen and methane; Adjusting the methane content in the second mixed gas to 6% to 12%; adjusting the temperature of the silicon carbide substrate to the diamond nucleation temperature; Maintain the above state for 5 to 20 minutes.

6. The method for improving the heat dissipation performance of a wafer according to claim 5, wherein: The diamond epitaxial growth process specifically includes: Adjusting the methane content in the second mixed gas to 4% to 6%; Cooling the silicon carbide substrate to a temperature 50° C. lower than the diamond nucleation temperature; The above state is maintained until the diamond layer on the back surface of the silicon carbide substrate grows to a desired value.

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