Silicon carbide seed crystal hot-pressing equipment

Abstract

The utility model relates to silicon carbide seed crystal hot-pressing equipment which comprises a vacuum cavity assembly, a pressure output device, a pressure head device and a heating support 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 communicated 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 pressure applying device is convenient to operate, stable pressure applying can be achieved, the occupied area is reduced, and the equipment cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to silicon carbide furnace equipment technical field, concretely relates to a silicon carbide seed crystal hot pressing equipment. BACKGROUND

[0002] As the third generation semiconductor material, silicon carbide has the characteristics of wide band gap, high breakdown field strength, high thermal conductivity, high electron saturation rate and strong anti-radiation ability, and is more suitable for manufacturing high-temperature, high-frequency, large-frequency and anti-radiation devices, and can be widely applied to high-voltage, high-frequency, high-temperature, high-reliability and other fields, including radio frequency communication, radar, satellite, power management, automobile electronics, industrial power electronics, etc.

[0003] At present, the most commonly used method for preparing silicon carbide is physical vapor transport (PVT). This process requires crystallization growth on a piece of silicon carbide seed crystal. The seed crystal needs to be bonded to a graphite cover by glue. During bonding, the silicon carbide seed crystal needs to be coated with glue multiple times, carbonized, and then bonded and solidified with the graphite cover. During the preparation process, it is necessary to ensure the firm combination between the seed crystal and the graphite cover, and the bonding layer after solidification is dense without any pores, otherwise it will cause sublimation on the back of the seed crystal and induce the formation of microtubules, dislocations and other defects, thereby reducing the growth quality of silicon carbide.

[0004] The seed crystal needs to be bonded at a certain pressure and temperature. The current commonly used vacuum hot pressing furnace has a pressure mode of hydraulic system pressure or pressure iron manual pressure. The hydraulic system pressure operation process is complicated, occupies a large area and has high equipment cost. The pressure iron manual pressure needs to be manually operated by a person, and the applied pressure is unstable. UTILITY MODEL CONTENTS

[0005] To solve the problems in the background art, the utility model provides a silicon carbide seed crystal hot pressing equipment. The utility model is convenient to operate, can realize stable pressure application, reduces the occupied area and reduces the equipment cost.

[0006] To solve the above problems, the utility model discloses the following technical scheme: A silicon carbide seed crystal hot-pressing equipment, including vacuum cavity assembly, pressure output device, pressure head device and heating support device, vacuum cavity assembly includes vacuum chamber, vacuum pressure gauge, resistance gauge, heating electrode, temperature measuring thermocouple and mechanical pump, the mechanical pump is communicated with and set in the bottom of vacuum chamber, vacuum pressure gauge and resistance gauge all are set on vacuum chamber, heating electrode and temperature measuring thermocouple all are arranged in the lateral wall of vacuum chamber and extend into vacuum chamber, and the side of vacuum chamber is provided with furnace door and is opened and closed, pressure output device is set in the top of vacuum chamber and the driving end is downwardly penetrated the top wall of vacuum chamber and can be lifted and is extended into vacuum chamber, and the driving part of pressure output device is circumscribed control system, pressure head device is set in the inside upper of vacuum chamber, and the upper end is connected with the driving end of pressure output device, heating support device is set on the inner bottom wall of vacuum chamber below pressure head device and is used for bearing graphite cover.

[0007] Further, 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 with the driving end of the pressure output device. The lower end of the pressure output shaft is provided with a insertion hole and is inserted with the ball head seat. The upper end of the universal ball head is rotatably arranged on the ball head seat. The lower end of the universal ball head is shaped as a plate structure and is connected with the pressure plate.

[0008] Further, the pressure head device further includes a buffer spring arranged in the insertion hole. One end of the buffer spring is connected with the inner end surface of the insertion hole. The other end of the buffer spring is connected with the top surface of the ball head seat. The end portions of the ball head seat are vertically provided with limiting grooves on both sides. The pressure output shaft is provided with limiting screws on both sides. The limiting screws are fixed by hexagonal nuts. The inner ends of the limiting screws are limitedly matched with the corresponding limiting grooves.

[0009] Further, the pressure head device further includes a flexible heat insulation felt. The flexible heat insulation felt 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] Further, the heating support device comprises a support shaft base, a plane load sensor, a flexible graphite heat preservation felt, a stainless steel base plate, a graphite base plate and a plurality of graphite heating bodies, the plane load sensor is arranged on the lower end of the support shaft base, the plane load sensor is arranged on the inner bottom wall of the vacuum chamber, the top of the support shaft base is formed with an inner groove and is used for bearing the stainless steel base plate, the flexible graphite heat preservation felt is arranged in the inner groove on the bottom of the stainless steel base plate, a plurality of heating cavities are formed in the stainless steel base plate, and the graphite heating bodies are arranged in the heating cavities in a one-to-one correspondence, the graphite base plate is arranged on the stainless steel base plate above the heating cavities and is used for bearing the graphite cover, and the inner end of the temperature measuring thermocouple extends into the heating cavity where the graphite heating body is arranged.

[0011] Further, the heating support device further comprises 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 plane load sensor, a vertical insertion hole is formed in the top surface of the water inlet connecting rod, a vertical cavity is formed in the lower end of the support shaft base, the lower end of the cooling water inlet pipe is inserted into the vertical insertion hole, the upper end of the cooling water inlet pipe is inserted into the vertical cavity, and a gap cavity is formed between the outer wall of the cooling water inlet pipe and the side surface of the vertical cavity, the water inlet joint is arranged on the side surface of the water inlet connecting rod and is communicated with the vertical insertion hole, and the water outlet joint is arranged on the side surface of the support shaft base and is communicated with the gap cavity.

[0012] Further, the pressure output device comprises 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 arranged on the seat body, the servo motor is connected with the precision planetary gear reducer in drive, the upper end of the ball screw is connected with the precision planetary gear reducer in drive through the transmission mechanism, and the lower end of the ball screw penetrates into the vacuum chamber downward and is connected with the pressure head device.

[0013] The utility model discloses have the advantage that: the utility model discloses through mechanical pump regulation vacuum chamber's vacuum degree, through resistance gauge and vacuum pressure gauge carry out pressure measurement and show, through heating electrode heats the graphite cover and carries out temperature measurement through temperature measuring thermocouple, and pressure output device drives pressure head device to move downward and is pressed with heating support device to realize the pressing of the seed crystal in the graphite cover, the utility model discloses can realize the accurate control of temperature, pressure and vacuum degree, compared with traditional hydraulic operation system, reduce the equipment volume and floor area, reduce the production cost, and the operation process is convenient and can realize stable pressure application. BRIEF DESCRIPTION OF DRAWINGS

[0014] The utility model is further illustrated below in combination with the drawings and embodiments.

[0015] Figure 1 It is the three-dimensional structure schematic view of the utility model;

[0016] Figure 2 It is the side view of the utility model;

[0017] Figure 3 It is the structure schematic view of pressure output device;

[0018] Figure 4 It is the structure schematic view of pressure head device;

[0019] Figure 5 It is the structure schematic view of heating support device.

[0020] 1, vacuum cavity 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, pressing plate;14, buffer spring;15, limit groove;16, limit screw;17, hexagon nut;18, flexible heat insulation felt;19, support shaft base;20, plane type load cell;21, flexible graphite heat insulation felt;22, stainless steel base plate;23, graphite base plate;24, graphite heating body;25, water inlet connecting rod;26, cooling water inlet pipe;27, water inlet joint;28, water outlet joint;29, seat body;30, servo motor;31, precision planetary gear reducer;32, transmission mechanism;33, ball screw;34, control system;35, resistance gauge. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0022] The utility model 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 utility model 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.

[0023] Specifically, such as 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. Chamber 2, a furnace door is provided on the side of the vacuum chamber 2; a pressure output device 7 is provided above the vacuum chamber 2, and the driving end thereof 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; a pressure head device 8 is provided above the interior of the vacuum chamber 2, and the upper end thereof is connected to the driving end of the pressure output device 7; a heating support device 9 is provided on the inner bottom wall of the vacuum chamber 2 below the pressure head device 8 and is used to support the graphite cover.

[0024] 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. The lower end of the pressure output shaft 10 is provided with a socket and is 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 is connected to the pressure plate 13.

[0025] 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. Limiting grooves 15 are vertically opened on both sides of the end of the ball head seat 11, and limiting screws 16 are passed through both sides of the pressure output shaft 10. The limiting screws 16 are fixed by hexagonal nuts 17, and the inner ends of the limiting screws 16 are limitedly matched with the corresponding limiting grooves 15.

[0026] Further, the pressure head device 8 further comprises a flexible thermal insulation felt 18, which 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.

[0027] Further, 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 base plate 22, a graphite base plate 23 and a plurality of graphite heating bodies 24, the planar load sensor 20 is arranged on the inner bottom wall of the vacuum chamber 2 at the lower end of the support shaft base 19, the top of the support shaft base 19 forms an inner groove and is used to carry the stainless steel base plate 22, the flexible graphite thermal insulation felt 21 is arranged in the inner groove at the bottom of the stainless steel base plate 22, a plurality of heating cavities are formed in the stainless steel base plate 22, and a plurality of graphite heating bodies 24 are correspondingly arranged in the heating cavities, the graphite base plate 23 is arranged on the stainless steel base plate 22 above the heating cavities and is used to carry the graphite cover, and the inner end of the temperature measuring thermocouple 5 extends into the heating cavity where the graphite heating body 24 is located.

[0028] Further, 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, the top surface of the water inlet connecting rod 25 is provided with a vertical insertion hole, the lower end of the support shaft base 19 is provided with a vertical cavity, the lower end of the cooling water inlet pipe 26 is inserted into the vertical insertion hole, the upper end of the cooling water inlet pipe 26 is inserted upward into the vertical cavity, and a gap cavity is formed between the outer wall of the cooling water inlet pipe 26 and the side surface of the vertical cavity, the water inlet joint 27 is arranged on the side surface of the water inlet connecting rod 25 and is in communication with the vertical insertion hole, and the water outlet joint 28 is arranged on the side surface of the support shaft base 19 and is in communication with the gap cavity.

[0029] Further, 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 drivingly connected with the precision planetary gear reducer 31, the upper end of the ball screw 33 is drivingly connected with 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 with the pressure head device 8.

[0030] The utility model discloses a mechanical pump 6 adjusts the vacuum degree of vacuum chamber 2, and the pressure is measured and is displayed through resistance gauge 35 and vacuum pressure gauge 3, and the graphite cover is heated through heating electrode 4 and is measured temperature through temperature measuring thermocouple 5, and pressure output device 7 drives pressure head device 8 to move down and is pressed with heating support device 9 to realize the pressing of the seed crystal in the graphite cover, the utility model discloses can realize the accurate control of temperature, pressure and vacuum degree, relative to traditional hydraulic operation system, has reduced the equipment size and floor space, has reduced production cost, and the operation process is convenient and can realize stable pressure application.

[0031] The above only is the preferred embodiment of the utility model, and does not use to limit the utility model, and any modification, equivalent replacement, improvement etc. that is made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A silicon carbide seed crystal hot pressing equipment, characterized in that: The utility model relates to a vacuum chamber total assembly (1) including vacuum chamber (2), vacuum pressure gauge (3), resistance gauge (35), heating electrode (4), temperature measuring thermocouple (5) and mechanical pump (6), the mechanical pump (6) is communicated and is arranged at the bottom of vacuum chamber (2), vacuum pressure gauge (3) and resistance gauge (35) are arranged on vacuum chamber (2), heating electrode (4) and temperature measuring thermocouple (5) are both worn in the lateral wall of vacuum chamber (2) and extend into vacuum chamber (2), and the side of vacuum chamber (2) is provided with furnace door and is opened and closed, Pressure output device (7) is arranged above vacuum chamber (2) and the driving end downwardly penetrates the top wall of vacuum chamber (2) and can be lifted and is extended into vacuum chamber (2), and the driving part of pressure output device (7) is connected with control system (34); Pressure head device (8) is arranged inside the upper of vacuum chamber (2), and the upper end is connected with the driving end of pressure output device (7); Heating support device (9) is arranged on the inner bottom wall of vacuum chamber (2) below pressure head device (8) and is used for bearing graphite cover. The pressure head device (8) includes pressure output shaft (10), ball head seat (11), universal ball head (12) and pressure plate (13), the upper end of pressure output shaft (10) is connected with the driving end of pressure output device (7), the lower end of pressure output shaft (10) is provided with a socket and is connected with ball head seat (11), the upper end of universal ball head (12) is rotatably arranged on ball head seat (11), the lower end of universal ball head (12) is shaped as a plate structure and is connected with pressure plate (13).

2. The apparatus for hot pressing silicon carbide seed crystal of claim 1, wherein: The pressure head device (8) further includes buffer spring (14) arranged in the socket, one end of buffer spring (14) is connected with the inner end surface of the socket, the other end is connected with the top surface of ball head seat (11), the end of ball head seat (11) is vertically provided with limiting groove (15) on both sides, the both sides of pressure output shaft (10) are provided with limiting screw (16), limiting screw (16) is fixed through hexagonal nut (17), the inner end of limiting screw (16) is limitedly matched with corresponding limiting groove (15).

3. The apparatus of claim 2, wherein: The pressure head device (8) further includes flexible heat insulation felt (18), which is fixedly arranged between the bottom surface of the plate-shaped lower end of universal ball head (12) and the top surface of pressure plate (13).

4. The apparatus of claim 2, wherein: ​ 5. The apparatus of claim 1, wherein: the graphite mold is formed of a graphite material having a thermal expansion coefficient of 5.0 x 10"6 cm / cm / °C or less. The heating support device (9) comprises a support shaft base (19), a planar load sensor (20), a flexible graphite heat preservation felt (21), a stainless steel base plate (22), a graphite base plate (23) and a plurality of graphite heating bodies (24), the lower end of the support shaft base (19) is provided with the planar load sensor (20), the planar load sensor (20) is arranged on the inner bottom wall of the vacuum chamber (2), the top of the support shaft base (19) is formed with an inner groove and is used for bearing the stainless steel base plate (22), the flexible graphite heat preservation felt (21) is arranged in the inner groove at the bottom of the stainless steel base plate (22), a plurality of heating cavities are formed in the stainless steel base plate (22), and a plurality of graphite heating bodies (24) are arranged in the heating cavities in one-to-one correspondence, the graphite base plate (23) is arranged on the stainless steel base plate (22) above the heating cavities and is used for bearing the graphite cover, and the inner end of the temperature measuring thermocouple (5) extends into the heating cavity where the graphite heating body (24) is located.

6. The apparatus of claim 5, wherein: 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), the top surface of the water inlet connecting rod (25) is provided with a vertical insertion hole, the lower end of the support shaft base (19) is provided with a vertical cavity, the lower end of the cooling water inlet pipe (26) is inserted into the vertical insertion hole, the upper end of the cooling water inlet pipe (26) is inserted upward into the vertical cavity, and a gap cavity is formed between the outer wall of the cooling water inlet pipe (26) and the side surface of the vertical cavity, the water inlet joint (27) is arranged on the side surface of the water inlet connecting rod (25) and communicates with the vertical insertion hole, and the water outlet joint (28) is arranged on the side surface of the support shaft base (19) and communicates with the gap cavity.

7. The apparatus of claim 1, wherein: the graphite mold is formed of a graphite material having a thermal expansion coefficient of 5.0 x 10"6 cm / cm / °C or less. 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 arranged on the seat body (29), the servo motor (30) is drivingly connected with the precision planetary gear reducer (31), the upper end of the ball screw (33) is drivingly connected with 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 with the pressure head device (8).

Images