Silicon carbide seed crystal hot-pressing equipment and seed crystal bonding method

Abstract

The invention relates to silicon carbide seed crystal hot-pressing equipment and a seed crystal bonding method.The silicon carbide seed crystal hot-pressing equipment comprises a vacuum cavity assembly, a pressure output device, a pressure head device and a heating supporting device.The vacuum cavity assembly comprises a vacuum chamber, a vacuum pressure gauge, a resistance gauge, a heating electrode, a temperature thermocouple and a mechanical pump, and the mechanical pump is arranged at the bottom of the vacuum chamber in a communicating mode; the vacuum pressure gauge and the resistance gauge are both arranged on the vacuum chamber, and the heating electrode and the temperature thermocouple are both arranged in the vacuum chamber in a penetrating manner; the pressure output device is arranged above the vacuum chamber, and the driving end of the pressure output device downwards penetrates through the top wall of the vacuum chamber and extends into the vacuum chamber in a lifting manner; the pressure head device is arranged above the interior of the vacuum chamber, and the upper end of the pressure head device is connected with the driving end of the pressure output device; and the heating support device is arranged on the inner bottom wall of the vacuum chamber below the pressure head device and is used for bearing the graphite cover. The device is convenient to operate, stable pressure application can be achieved, the occupied area is reduced, and the equipment cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide furnace equipment, and in particular to silicon carbide seed crystal hot pressing equipment and a seed crystal bonding method. Background Art

[0002] As a third-generation semiconductor material, silicon carbide has the characteristics of large bandgap, high breakdown field strength, high thermal conductivity, high electron saturation rate and strong radiation resistance. It is more suitable for manufacturing high-temperature, high-frequency, large-frequency and radiation-resistant devices, and can be widely used in high voltage, high frequency, high temperature, high reliability and other fields, including radio frequency communications, radars, satellites, power management, automotive electronics, industrial power electronics, etc.

[0003] The most commonly used method for preparing silicon carbide at present is physical vapor transport (PVT). This process requires crystal growth on a piece of silicon carbide seed crystal, and the seed crystal needs to be bonded to the graphite cover with glue. During bonding, the silicon carbide seed crystal needs to be coated with glue multiple times, carbonized, and then bonded and cured with the graphite cover. During the preparation process, it is necessary to ensure a firm bond between the seed crystal and the graphite cover, and at the same time, the cured bonding layer is dense and has no holes, otherwise it will cause sublimation on the back of the seed crystal and induce the formation of defects such as microtubes and dislocations, thereby reducing the growth quality of silicon carbide.

[0004] Seed crystal bonding needs to be done under a certain pressure and temperature. Currently, the commonly used pressurization methods of vacuum hot pressing furnaces are hydraulic system pressurization or manual pressurization with iron pressure. The hydraulic system pressurization operation process is cumbersome, occupies a large area and has high equipment cost. Manual pressurization with iron pressure requires manual operation by people, and the applied pressure is unstable. Summary of the invention

[0005] In order to solve the problems in the background technology, the present invention proposes a silicon carbide seed crystal hot pressing equipment and a seed crystal bonding method. The present invention is easy to operate and can achieve stable pressure, which reduces the floor space and reduces the equipment cost.

[0006] To solve the above problems, the present invention adopts the following technical scheme: a silicon carbide seed crystal hot pressing equipment, including a vacuum chamber assembly, a pressure output device, a pressure head device and a heating support device, the vacuum chamber assembly includes a vacuum chamber, a vacuum pressure gauge, a resistance gauge, a heating electrode, a temperature measuring thermocouple and a mechanical pump, the mechanical pump is connected and arranged at the bottom of the vacuum chamber, the vacuum pressure gauge and the resistance gauge are both arranged on the vacuum chamber, the heating electrode and the temperature measuring thermocouple are both penetrated through the side wall of the vacuum chamber and extend into the vacuum chamber, and a furnace door is opened and closed on the side of the vacuum chamber; the pressure output device is arranged above the vacuum chamber and the driving end downwardly penetrates the top wall of the vacuum chamber and can be raised and lowered into the vacuum chamber, and the driving part of the pressure output device is externally connected to the control system; the pressure head device is arranged above the interior of the vacuum chamber, and the upper end is connected to the driving end of the pressure output device; the heating support device is arranged on the inner bottom wall of the vacuum chamber below the pressure head device and is used to carry the graphite cover.

[0007] Furthermore, the pressure head device includes a pressure output shaft, a ball head seat, a universal ball head and a pressure plate. The upper end of the pressure output shaft is connected to the driving end of the pressure output device, the lower end of the pressure output shaft is provided with a socket and is plugged into the ball head seat, the upper end of the universal ball head is rotatably set on the ball head seat, and the lower end of the universal ball head is formed into a plate-like structure and is connected to the pressure plate.

[0008] Furthermore, the pressure head device also includes a buffer spring arranged in the socket, one end of the buffer spring is connected to the inner end surface of the socket, and the other end is connected to the top surface of the ball head seat, and limiting grooves are vertically opened on both sides of the end of the ball head seat, and limiting screws are passed through both sides of the pressure output shaft. The limiting screws are fixed by hexagonal nuts, and the inner end of the limiting screw is limitedly matched with the corresponding limiting groove.

[0009] Furthermore, the pressure head device also includes a flexible thermal insulation felt, which is fixedly arranged between the bottom surface of the plate-shaped lower end of the universal ball head and the top surface of the pressure plate.

[0010] Furthermore, the heating support device includes a support shaft base, a planar load sensor, a flexible graphite insulation felt, a stainless steel chassis, a graphite chassis and multiple graphite heating elements. The planar load sensor is arranged at the lower end of the support shaft base, and the planar load sensor is arranged on the inner bottom wall of the vacuum chamber. The top of the support shaft base forms an inner groove and is used to support the stainless steel chassis. The flexible graphite insulation felt is arranged in the inner groove at the bottom of the stainless steel chassis. Multiple heating cavities are formed in the stainless steel chassis, and multiple graphite heating elements are arranged in the multiple heating cavities one by one. The graphite chassis is arranged on the stainless steel chassis above the multiple heating cavities and is used to support the graphite cover. The inner end of the temperature measuring thermocouple extends into the heating cavity where the graphite heating element is located.

[0011] Furthermore, the heating support device also includes a water inlet connecting rod, a cooling water inlet pipe, a water inlet joint and a water outlet joint. The water inlet connecting rod is arranged between the support shaft base and the planar load sensor. A vertical socket is opened on the top surface of the water inlet connecting rod, and a vertical cavity is opened at the lower end of the support shaft base. The lower end of the cooling water inlet pipe is inserted into the vertical socket, and the upper end is upwardly inserted into the vertical cavity and a gap cavity is formed between the outer wall of the cooling water inlet pipe and the side of the vertical cavity. The water inlet joint is arranged on the side of the water inlet connecting rod and is connected with the vertical socket, and the water outlet joint is arranged on the side of the support shaft base and is connected with the gap cavity.

[0012] Furthermore, the pressure output device includes a seat body, a servo motor, a precision planetary gear reducer, a transmission mechanism and a ball screw. The seat body is arranged on the vacuum chamber, the precision planetary gear reducer and the transmission mechanism are both arranged on the seat body, the servo motor is drivingly connected to the precision planetary gear reducer, the upper end of the ball screw is drivingly connected to the precision planetary gear reducer through the transmission mechanism, and the lower end of the ball screw penetrates downward into the vacuum chamber and is connected to the pressure head device.

[0013] Furthermore, a seed crystal bonding method is provided, using the above silicon carbide seed crystal hot pressing equipment, the seed crystal bonding method comprising the following steps:

[0014] Step 1: Glue absorption on graphite cover: Check the flatness of graphite cover, polish the surface of graphite cover with sandpaper and wipe it clean, apply glue on the cleaned blade ruler, and use the blade ruler to scrape glue on the graphite cover horizontally and vertically twice to ensure that the whole surface is covered with glue;

[0015] Step 2, seed crystal coating treatment: weigh the seed crystal with an electronic scale, observe and record the surface shape and defects of the seed crystal, place the seed crystal on a coating machine, place 10 ml of positive photoresist on the seed crystal and coat it twice, and then put the seed crystal into a vacuum chamber at 1000°C for carbonization treatment for 1 hour;

[0016] Step 3: Seed crystal bonding: Use a micrometer to measure the curvature of the seed crystal, stick a PET film on the growth surface of the seed crystal, apply glue on a cleaned ruler, use the ruler to scrape glue horizontally and vertically on the silicon surface of the seed crystal twice to ensure that the entire surface is covered with glue, stick the graphite paper surface of the seed crystal to the graphite cover, use a silicone roller to drive glue on the seed crystal for 3 minutes, and remove the glue overflow on the edge;

[0017] Step 4: Hot pressing and curing: Place the bonded seed crystal graphite cap in the silicon carbide seed crystal hot pressing equipment for hot pressing and curing. After the hot pressing is completed, naturally cool to 60°C, remove the seed crystal graphite cap, and the seed crystal bonding is completed.

[0018] Furthermore, the parameters of the second pass of the coating in step 2 are as follows:

[0019] Parameters of the first layer of glue machine: low speed 700 rpm, time 8 seconds, high speed 4000 rpm, time 30 seconds;

[0020] Parameters of the second layer of glue spreader: low speed 800 rpm, time 10 seconds, high speed 4500 rpm, time 45 seconds.

[0021] Furthermore, the parameters of the silicon carbide seed crystal hot pressing equipment in step 4 are as follows:

[0022] Pressure 100kg, temperature 50℃, time 30 minutes;

[0023] Pressure 150kg, temperature 140℃, time 60 minutes;

[0024] Pressure 300kg, temperature 260℃, time 30 minutes;

[0025] Pressure 400kg, temperature 450℃, time 20 minutes.

[0026] Beneficial effects of the present invention: the present invention adjusts the vacuum degree of the vacuum chamber through a mechanical pump, measures and displays the pressure through a resistance gauge and a vacuum pressure gauge, heats the graphite cover through a heating electrode and measures the temperature through a temperature measuring thermocouple, and the pressure output device drives the pressure head device to move downward and press with the heating support device to achieve the pressing of the seed crystal in the graphite cover. The present invention can achieve precise control of temperature, pressure and vacuum degree. Compared with traditional hydraulic operating systems, the equipment volume and floor space are reduced, the production cost is reduced, the operation process is convenient and stable pressure can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0029] Figure 2 is a side view of the present invention;

[0030] Figure 3 It is a structural schematic diagram of a pressure output device;

[0031] Figure 4 It is a structural schematic diagram of the pressure head device;

[0032] Figure 5 It is a schematic diagram of the structure of the heating support device.

[0033] 1. Vacuum chamber assembly; 2. Vacuum chamber; 3. Vacuum pressure gauge; 4. Heating electrode; 5. Temperature measuring thermocouple; 6. Mechanical pump; 7. Pressure output device; 8. Pressure head device; 9. Heating support device; 10. Pressure output shaft; 11. Ball head seat; 12. Universal ball head; 13. Pressure plate; 14. Buffer spring; 15. Limiting groove; 16. Limiting screw; 17. Hexagonal nut; 18. Flexible insulation felt; 19. Support shaft base; 20. Planar load sensor; 21. Flexible graphite insulation felt; 22. Stainless steel chassis; 23. Graphite chassis; 24. Graphite heating element; 25. Water inlet connecting rod; 26. Cooling water inlet pipe; 27. Water inlet joint; 28. Water outlet joint; 29. ​​Seat; 30. Servo motor; 31. Precision planetary gear reducer; 32. Transmission mechanism; 33. Ball screw; 34. Control system; 35. Resistance gauge. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0035] The present invention adjusts the vacuum degree of the vacuum chamber 2 through a mechanical pump 6, measures and displays the pressure through a resistance gauge 35 and a vacuum pressure gauge 3, heats the graphite cover through a heating electrode 4 and measures the temperature through a temperature measuring thermocouple 5, and a pressure output device 7 drives a pressure head device 8 to move downward and press it with a heating support device 9 to achieve the pressing of the seed crystal in the graphite cover. The present invention can achieve precise control of temperature, pressure and vacuum degree. Compared with traditional hydraulic operating systems, the equipment volume and floor space are reduced, the production cost is reduced, the operation process is convenient and stable pressure can be achieved.

[0036] Specifically, Figures 1 to 5 As shown, a silicon carbide seed crystal hot pressing equipment includes a vacuum chamber assembly 1, a pressure output device 7, a pressure head device 8 and a heating support device 9. The vacuum chamber assembly 1 includes a vacuum chamber 2, a vacuum pressure gauge 3, a resistance gauge 35, a heating electrode 4, a temperature measuring thermocouple 5 and a mechanical pump 6. The mechanical pump 6 is connected and arranged at the bottom of the vacuum chamber 2. The vacuum pressure gauge 3 and the resistance gauge 35 are both arranged on the vacuum chamber 2. The heating electrode 4 and the temperature measuring thermocouple 5 are both arranged on the side wall of the vacuum chamber 2 and extend into the vacuum chamber. The vacuum chamber 2 is in a chamber 2, and a furnace door is opened and closed on the side of the vacuum chamber 2; the pressure output device 7 is arranged above the vacuum chamber 2, and the driving end downwardly penetrates the top wall of the vacuum chamber 2 and can be raised and lowered into the vacuum chamber 2, and the driving part of the pressure output device 7 is externally connected to the control system 34; the pressure head device 8 is arranged above the interior of the vacuum chamber 2, and the upper end is connected to the driving end of the pressure output device 7; the heating support device 9 is arranged on the inner bottom wall of the vacuum chamber 2 below the pressure head device 8 and is used to carry the graphite cover.

[0037] Furthermore, the pressure head device 8 includes a pressure output shaft 10, a ball head seat 11, a universal ball head 12 and a pressure plate 13. The upper end of the pressure output shaft 10 is connected to the driving end of the pressure output device 7, and the lower end of the pressure output shaft 10 is provided with a socket and plugged into the ball head seat 11. The upper end of the universal ball head 12 is rotatably set on the ball head seat 11, and the lower end of the universal ball head 12 is formed into a plate-like structure and connected to the pressure plate 13.

[0038] Furthermore, the pressure head device 8 also includes a buffer spring 14 arranged in the socket, one end of the buffer spring 14 is connected to the inner end surface of the socket, and the other end is connected to the top surface of the ball head seat 11, and limiting grooves 15 are vertically opened on both sides of the end of the ball head seat 11. Limit screws 16 are passed through both sides of the pressure output shaft 10, and the limit screws 16 are fixed by hexagonal nuts 17. The inner end of the limit screw 16 is limitedly matched with the corresponding limit groove 15.

[0039] Furthermore, the pressing head device 8 also includes a flexible thermal insulation felt 18 , and the flexible thermal insulation felt 18 is fixedly arranged between the bottom surface of the plate-shaped lower end of the universal ball head 12 and the top surface of the pressing plate 13 .

[0040] Furthermore, the heating support device 9 includes a support shaft base 19, a planar load sensor 20, a flexible graphite insulation felt 21, a stainless steel chassis 22, a graphite chassis 23 and a plurality of graphite heating elements 24. The planar load sensor 20 is arranged at the lower end of the support shaft base 19, and the planar load sensor 20 is arranged on the inner bottom wall of the vacuum chamber 2. An inner groove is formed at the top of the support shaft base 19 and is used to support the stainless steel chassis 22. The flexible graphite insulation felt 21 is arranged in the inner groove at the bottom of the stainless steel chassis 22. A plurality of heating cavities are formed in the stainless steel chassis 22, and a plurality of graphite heating elements 24 are arranged in the plurality of heating cavities one by one. The graphite chassis 23 is arranged on the stainless steel chassis 22 above the plurality of heating cavities and is used to support the graphite cover. The inner end of the temperature measuring thermocouple 5 extends into the heating cavity where the graphite heating element 24 is located.

[0041] Furthermore, the heating support device 9 also includes a water inlet connecting rod 25, a cooling water inlet pipe 26, a water inlet joint 27 and a water outlet joint 28. The water inlet connecting rod 25 is arranged between the support shaft base 19 and the planar load sensor 20. A vertical socket is opened on the top surface of the water inlet connecting rod 25, and a vertical cavity is opened at the lower end of the support shaft base 19. The lower end of the cooling water inlet pipe 26 is inserted into the vertical socket, and the upper end is upwardly inserted into the vertical cavity and a gap cavity is formed between the outer wall of the cooling water inlet pipe 26 and the side of the vertical cavity. The water inlet joint 27 is arranged on the side of the water inlet connecting rod 25 and is connected to the vertical socket, and the water outlet joint 28 is arranged on the side of the support shaft base 19 and is connected to the gap cavity.

[0042] Furthermore, the pressure output device 7 includes a seat body 29, a servo motor 30, a precision planetary gear reducer 31, a transmission mechanism 32 and a ball screw 33. The seat body 29 is arranged on the vacuum chamber 2, the precision planetary gear reducer 31 and the transmission mechanism 32 are both arranged on the seat body 29, the servo motor 30 is drivingly connected to the precision planetary gear reducer 31, the upper end of the ball screw 33 is drivingly connected to the precision planetary gear reducer 31 through the transmission mechanism 32, and the lower end of the ball screw 33 penetrates downward into the vacuum chamber 2 and is connected to the pressure head device 8.

[0043] Furthermore, a seed crystal bonding method is provided, using the above silicon carbide seed crystal hot pressing equipment, the seed crystal bonding method comprising the following steps:

[0044] Step 1: Glue absorption on graphite cover: Check the flatness of graphite cover, polish the surface of graphite cover with sandpaper and wipe it clean, apply glue on the cleaned blade ruler, and use the blade ruler to scrape glue on the graphite cover horizontally and vertically twice to ensure that the whole surface is covered with glue;

[0045] Step 2, seed crystal coating treatment: weigh the seed crystal with an electronic scale, observe and record the surface shape and defects of the seed crystal, place the seed crystal on a coating machine, place 10 ml of positive photoresist on the seed crystal and coat it twice, and then put the seed crystal into a vacuum chamber 2 at 1000°C for carbonization treatment for 1 hour;

[0046] Step 3: Seed crystal bonding: Use a micrometer to measure the curvature of the seed crystal, stick a PET film on the growth surface of the seed crystal, apply glue on a cleaned ruler, use the ruler to scrape glue horizontally and vertically on the silicon surface of the seed crystal twice to ensure that the entire surface is covered with glue, stick the graphite paper surface of the seed crystal to the graphite cover, use a silicone roller to drive glue on the seed crystal for 3 minutes, and remove the glue overflow on the edge;

[0047] Step 4: Hot pressing and curing: Place the bonded seed crystal graphite cap in the silicon carbide seed crystal hot pressing equipment for hot pressing and curing. After the hot pressing is completed, naturally cool to 60°C, remove the seed crystal graphite cap, and the seed crystal bonding is completed.

[0048] Furthermore, the parameters of the second pass of the coating in step 2 are as follows:

[0049] Parameters of the first layer of glue machine: low speed 700 rpm, time 8 seconds, high speed 4000 rpm, time 30 seconds;

[0050] Parameters of the second layer of glue spreader: low speed 800 rpm, time 10 seconds, high speed 4500 rpm, time 45 seconds.

[0051] Furthermore, the parameters of the silicon carbide seed crystal hot pressing equipment in step 4 are as follows:

[0052] Pressure 100kg, temperature 50℃, time 30 minutes;

[0053] Pressure 150kg, temperature 140℃, time 60 minutes;

[0054] Pressure 300kg, temperature 260℃, time 30 minutes;

[0055] Pressure 400kg, temperature 450℃, time 20 minutes.

[0056] The present invention adjusts the vacuum degree of the vacuum chamber 2 through a mechanical pump 6, measures and displays the pressure through a resistance gauge 35 and a vacuum pressure gauge 3, heats the graphite cover through a heating electrode 4 and measures the temperature through a temperature measuring thermocouple 5, and a pressure output device 7 drives a pressure head device 8 to move downward and press it with a heating support device 9 to achieve the pressing of the seed crystal in the graphite cover. The present invention can achieve precise control of temperature, pressure and vacuum degree. Compared with traditional hydraulic operating systems, the equipment volume and floor space are reduced, the production cost is reduced, the operation process is convenient and stable pressure can be achieved.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A silicon carbide seed crystal hot pressing equipment, characterized in that: include: A vacuum chamber assembly (1) comprises a vacuum chamber (2), a vacuum pressure gauge (3), a resistance gauge (35), a heating electrode (4), a temperature measuring thermocouple (5) and a mechanical pump (6); the mechanical pump (6) is arranged in communication at the bottom of the vacuum chamber (2); the vacuum pressure gauge (3) and the resistance gauge (35) are both arranged on the vacuum chamber (2); the heating electrode (4) and the temperature measuring thermocouple (5) are both arranged through the side wall of the vacuum chamber (2) and extend into the vacuum chamber (2); and a furnace door is arranged on the side of the vacuum chamber (2); A pressure output device (7) is arranged above the vacuum chamber (2) and has a driving end that passes through the top wall of the vacuum chamber (2) and extends into the vacuum chamber (2) in a manner that allows it to be lifted or lowered. The driving part of the pressure output device (7) is externally connected to a control system (34); A pressure head device (8) is arranged above the interior of the vacuum chamber (2), and the upper end of the pressure head device (8) is connected to the driving end of the pressure output device (7); A heating support device (9) is arranged on the inner bottom wall of the vacuum chamber (2) below the pressure head device (8) and is used to support the graphite cover.

2. The silicon carbide seed crystal hot pressing equipment according to claim 1, characterized in that: The pressure head device (8) comprises a pressure output shaft (10), a ball head seat (11), a universal ball head (12) and a pressure plate (13); the upper end of the pressure output shaft (10) is connected to the driving end of the pressure output device (7); the lower end of the pressure output shaft (10) is provided with a socket and is plugged into and matched with the ball head seat (11); the upper end of the universal ball head (12) is rotatably arranged on the ball head seat (11); the lower end of the universal ball head (12) is formed into a plate-like structure and is connected to the pressure plate (13).

3. The silicon carbide seed crystal hot pressing equipment according to claim 2, characterized in that: The pressure head device (8) also includes a buffer spring (14) arranged in the socket, one end of the buffer spring (14) is connected to the inner end surface of the socket, and the other end is connected to the top surface of the ball head seat (11), and both sides of the end of the ball head seat (11) are vertically provided with limit grooves (15), and both sides of the pressure output shaft (10) are penetrated by limit screws (16), and the limit screws (16) are fixed by hexagonal nuts (17), and the inner end of the limit screw (16) is limitedly matched with the corresponding limit groove (15).

4. The silicon carbide seed crystal hot pressing equipment according to claim 2, characterized in that: The pressure head device (8) also includes a flexible thermal insulation felt (18), and the flexible thermal insulation felt (18) is fixedly arranged between the bottom surface of the plate-shaped lower end of the universal ball head (12) and the top surface of the pressure plate (13).

5. The silicon carbide seed crystal hot pressing equipment according to claim 1, characterized in that: The heating support device (9) comprises a support shaft base (19), a planar load sensor (20), a flexible graphite thermal insulation felt (21), a stainless steel chassis (22), a graphite chassis (23) and a plurality of graphite heating elements (24); the planar load sensor (20) is arranged at the lower end of the support shaft base (19); the planar load sensor (20) is arranged on the inner bottom wall of the vacuum chamber (2); an inner groove is formed at the top of the support shaft base (19) and is used to support the stainless steel chassis (22), the flexible graphite insulation felt (21) is arranged in the inner groove at the bottom of the stainless steel chassis (22), a plurality of heating chambers are formed in the stainless steel chassis (22), a plurality of graphite heating elements (24) are arranged in the plurality of heating chambers in a one-to-one correspondence, the graphite chassis (23) is arranged on the stainless steel chassis (22) above the plurality of heating chambers and is used to support the graphite cover, and the inner end of the temperature measuring thermocouple (5) extends into the heating chamber where the graphite heating element (24) is located.

6. The silicon carbide seed crystal hot pressing equipment according to claim 5, characterized in that: The heating support device (9) further comprises a water inlet connecting rod (25), a cooling water inlet pipe (26), a water inlet joint (27) and a water outlet joint (28); the water inlet connecting rod (25) is arranged between the support shaft base (19) and the planar load sensor (20); a vertical plug hole is provided on the top surface of the water inlet connecting rod (25); a vertical cavity is provided at the lower end of the support shaft base (19); the lower end of the cooling water inlet pipe (26) is inserted into the vertical plug hole, and the upper end is inserted upward into the vertical cavity; a gap cavity is formed between the outer wall of the cooling water inlet pipe (26) and the side of the vertical cavity; the water inlet joint (27) is arranged on the side of the water inlet connecting rod (25) and communicated with the vertical plug hole; the water outlet joint (28) is arranged on the side of the support shaft base (19) and communicated with the gap cavity.

7. The silicon carbide seed crystal hot pressing equipment according to claim 1, characterized in that: The pressure output device (7) comprises a seat body (29), a servo motor (30), a precision planetary gear reducer (31), a transmission mechanism (32) and a ball screw (33); the seat body (29) is arranged on the vacuum chamber (2); the precision planetary gear reducer (31) and the transmission mechanism (32) are both arranged on the seat body (29); the servo motor (30) is connected to the precision planetary gear reducer (31) by driving; the upper end of the ball screw (33) is connected to the precision planetary gear reducer (31) by driving through the transmission mechanism (32); the lower end of the ball screw (33) penetrates downward into the vacuum chamber (2) and is connected to the pressure head device (8).

8. A seed crystal bonding method, characterized in that: Using the silicon carbide seed crystal hot pressing equipment as described in any one of claims 1 to 7, the seed crystal bonding method comprises the following steps: Step 1: Glue absorption on graphite cover: Check the flatness of graphite cover, polish the surface of graphite cover with sandpaper and wipe it clean, apply glue on the cleaned blade ruler, and use the blade ruler to scrape glue on the graphite cover horizontally and vertically twice to ensure that the whole surface is covered with glue; Step 2, seed crystal coating treatment: weigh the seed crystal with an electronic scale, observe and record the surface shape and defects of the seed crystal, place the seed crystal on a coating machine, place 10 ml of positive photoresist on the seed crystal and coat it twice, and then place the seed crystal in a vacuum chamber (2) at 1000° C. for carbonization treatment for 1 hour; Step 3: Seed crystal bonding: Use a micrometer to measure the curvature of the seed crystal, stick a PET film on the growth surface of the seed crystal, apply glue on a cleaned ruler, use the ruler to scrape glue horizontally and vertically on the silicon surface of the seed crystal twice to ensure that the entire surface is covered with glue, stick the graphite paper surface of the seed crystal to the graphite cover, use a silicone roller to drive glue on the seed crystal for 3 minutes, and remove the glue overflow on the edge; Step 4: Hot pressing and curing: Place the bonded seed crystal graphite cap in the silicon carbide seed crystal hot pressing equipment for hot pressing and curing. After the hot pressing is completed, naturally cool to 60°C, remove the seed crystal graphite cap, and the seed crystal bonding is completed.

9. A seed crystal bonding method according to claim 8, characterized in that: The parameters of the second pass of the coating in step 2 are as follows: Parameters of the first layer of glue machine: low speed 700 rpm, time 8 seconds, high speed 4000 rpm, time 30 seconds; Parameters of the second layer of glue spreader: low speed 800 rpm, time 10 seconds, high speed 4500 rpm, time 45 seconds.

10. A seed crystal bonding method according to claim 8, characterized in that: The parameters of the silicon carbide seed crystal hot pressing equipment in step 4 are as follows: Pressure 100kg, temperature 50℃, time 30 minutes; Pressure 150kg, temperature 140℃, time 60 minutes; Pressure 300kg, temperature 260℃, time 30 minutes; Pressure 400kg, temperature 450℃, time 20 minutes.

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