Novel carbonization furnace for bonding silicon carbide seed crystals

Abstract

The utility model discloses a novel carbonization furnace for bonding silicon carbide seed crystals, which comprises a lifting mechanism, a base and a cover body, the cover body is arranged at the top of the base, and the lifting mechanism is used for lifting the cover body; a cover body is arranged on the base, a hydraulic driving mechanism is arranged at the top of the cover body, a dowel bar is connected to the driving end of the hydraulic driving mechanism, one end of the dowel bar extends into the cover body and is connected with an upper pressing block, a supporting seat is arranged on the base below the upper pressing block, and a heating mechanism and a temperature measuring mechanism are arranged in the supporting seat; and an upper heat insulation screen is arranged at the top of the interior of the cover body on the outer side of the dowel bar, a lower heat insulation screen is arranged on the base at the bottom of the interior of the cover body on the outer side of the supporting seat, and the lower heat insulation screen is located on the inner side of the upper heat insulation screen. The sintering temperature can be accurately controlled through the heating mechanism and the temperature measuring mechanism which are arranged in the supporting seat, the heat loss of a sample heating area, the overheating of the cover body and the like are reduced through the upper heat insulation screen and the lower heat insulation screen, and the temperature control precision and the pressure control precision are effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of silicon carbide seed crystal bonding, and specifically relates to a novel carbonization furnace for bonding silicon carbide seed crystals. Background Art

[0002] Silicon carbide materials are widely used in the optoelectronic field and are the basis for the preparation of silicon carbide crystal devices. Before the growth of silicon carbide crystals, the prepared seed crystals need to be bonded to the graphite parts. Usually, they are bonded with epoxy glue at room temperature and then placed in a carbonization furnace for sintering. The quality of seed crystal bonding is crucial to the subsequent growth of silicon carbide crystals, so the carbonization furnace is an important equipment in the entire production process.

[0003] The basic function of a carbonization furnace is to provide a vacuum environment, necessary pressure and sufficiently high temperature (≥450°C). Common carbonization furnaces include a vacuum system, a hot pressing system and a control system. The hot pressing system includes a heating device and a pressurizing device. The use of metal blocks for pressurization is more common and has a lower cost. However, in actual work, it is found that the carbonization process is relatively long, and the temperature control and pressure control accuracy are high. Simple carbonization furnaces are prone to problems such as uncontrollable pressure, poor temperature stability, and severe heat loss, resulting in low product quality, poor stability, and high energy consumption. Utility Model Content

[0004] The utility model aims to provide a novel carbonization furnace for bonding silicon carbide seed crystals, aiming to solve the above-mentioned problems.

[0005] The utility model is mainly realized through the following technical solutions:

[0006] A novel carbonization furnace for bonding silicon carbide seed crystals comprises a lifting mechanism, a base, a cover body and a pressing and holding fixture, wherein a cover body is arranged on the top of the base, and the lifting mechanism is used to lift the cover body; the pressing and holding fixture comprises a linear drive mechanism, an upper pressing block and a support seat, a linear drive mechanism is arranged on the top of the cover body, a driving end of the linear drive mechanism extends into the cover body and is connected to the upper pressing block, a support seat is arranged on the base below the upper pressing block, a heating mechanism and a temperature measuring mechanism are arranged inside the support seat; an upper heat insulation screen is arranged on the top of the inside of the cover body, a lower heat insulation screen is arranged on the base at the bottom of the inside of the cover body outside the support seat, and the lower heat insulation screen is located on the inner side of the upper heat insulation screen.

[0007] In order to better realize the utility model, further, the linear drive mechanism includes a hydraulic drive mechanism and a force transmission rod. The top of the cover body is provided with a hydraulic drive mechanism, and the driving end of the hydraulic drive mechanism is connected to the force transmission rod. One end of the force transmission rod extends into the interior of the cover body and is connected to the upper pressure block.

[0008] In order to better realize the utility model, further, a bellows is sleeved and installed on the outer side of the upper part of the force transmission rod, and the force transmission rod is connected to the top of the cover body through the bellows.

[0009] In order to better realize the utility model, further, a cooling mechanism is provided in the middle of the force transmission rod located inside the cover body along the length direction.

[0010] In order to better realize the utility model, further, the cooling mechanism includes a metal cooling pipe, and the middle part of the force transmission rod is surrounded by the metal cooling pipe along the length direction; the water inlet end and the water outlet end of the metal cooling pipe respectively pass through the corrugated pipe and extend out of the top of the cover body.

[0011] In order to better realize the utility model, further, an air intake valve and a manual air release valve are respectively arranged on both sides of the top of the cover body; an air suction port is arranged on the base at the bottom of the inside of the cover body, and a cooling cavity with an annular structure is arranged on the surrounding side of the air suction port, and a water inlet and a water outlet are correspondingly arranged on the cooling cavity.

[0012] In order to better realize the utility model, further, a vacuum gauge interface and a multi-core flange interface are also provided on the base at the bottom of the cover body.

[0013] In order to better implement the utility model, further, a lifting ear is arranged on the outer side of the cover body, and the driving end of the lifting mechanism slides through the base and is connected to the lifting ear.

[0014] In order to better realize the utility model, further, the upper heat insulation screen and the lower heat insulation screen are both cylindrical structures, and the top of the lower heat insulation screen extends into the inner side of the upper heat insulation screen.

[0015] The beneficial effects of the utility model are as follows:

[0016] (1) The utility model lifts the cover body through the lifting mechanism so that the sample can be placed on the support seat; the utility model can accurately control the carbonization temperature through the heating mechanism and temperature measuring mechanism built into the support seat. Secondly, under the action of the upper heat insulation screen and the lower heat insulation screen, the heat loss caused by the heat radiation in the sample heating area and the overheating of the cover body are reduced, the accuracy of temperature control and pressure control is effectively improved, the temperature stability is improved, and it has good practicality;

[0017] (2) The utility model drives the force transmission rod and the upper pressure block to rise and fall through a hydraulic drive mechanism, so as to facilitate dynamic pressurization of the sample between the upper pressure block and the support seat; the utility model is based on the hydraulic force-adding method, and can realize dynamic pressure adjustment of the whole process through PLC control, avoiding the limitation of static pressure constant force of the pressure block, which is conducive to obtaining high-quality bonding samples;

[0018] (3) The force transmission rod of the utility model is connected to the housing through a bellows, which ensures the stability of the vacuum degree inside the cavity during the working process and reduces the possibility of leakage. In addition, the outer side of the integrally formed force transmission rod is provided with cooling protection, which avoids the pressure inaccuracy and instability that may be caused by other force transmission methods, and has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural schematic diagram of a novel carbonization furnace for bonding silicon carbide seed crystals according to the utility model;

[0020] Figure 2 is a schematic diagram of the connection structure between the base and the cover;

[0021] Figure 3 It is a structural schematic diagram of the pressing tooling.

[0022] Among them: 1-base, 2-lifting mechanism, 3-lifting ear, 4-upper pressure block, 5-cover, 6-upper heat insulation screen, 8-bellows, 10-hydraulic drive mechanism, 12-metal cooling pipe, 14-force transmission rod, 16-support seat, 17-lower heat insulation screen, 18-thermocouple, 19-multi-core flange interface, 21-cooling cavity, 22-exhaust port, 24-vacuum gauge interface. DETAILED DESCRIPTION

[0023] Embodiment 1:

[0024] A novel carbonization furnace for bonding silicon carbide seed crystals includes a cover body 5, a base 1 and a lifting mechanism 2. The lifting mechanism 2 is used to lift the cover body 5 relative to the base 1, and a sealing mechanism is provided between the cover body 5 and the base 1. The sealing mechanism can be a sealing ring to ensure that a sealed cavity is formed between the cover body 5 and the base 1. A hydraulic drive mechanism 10 is provided on the top of the cover body 5. The driving end of the hydraulic drive mechanism 10 is connected to a force transmission rod 14. The free end of the force transmission rod 14 extends into the interior of the cover body 5 and is connected to the upper pressing block 4. A support seat 16 is provided on the base 1 inside the cover body 5 corresponding to the upper pressing block 4. A heating mechanism and a temperature measuring mechanism are provided inside the support seat 16. A multi-core flange interface 19 is provided on the base 1 corresponding to the heating mechanism and the temperature measuring thermocouple 18.

[0025] Preferably, the upper outer side of the force transmission rod 14 is sleeved with a bellows 8, and the force transmission rod 14 is connected to the cover body 5 through the bellows 8. The middle part of the force transmission rod 14 is wrapped with a metal cooling pipe 12, and the water inlet and outlet of the metal cooling pipe 12 respectively pass through the bellows 8 and extend to the outside of the cover body 5. In the utility model, the force transmission rod 14 is connected to the cover body 5 through the bellows 8, which ensures the stability of the vacuum degree inside the cavity during the working process and the possibility of leakage is low. In addition, the outer side of the integrally formed force transmission rod 14 is provided with cooling protection, which avoids the pressure inaccuracy and instability that may be caused by other force transmission methods, and has good practicality.

[0026] Preferably, an upper heat insulation screen 6 of a cylindrical structure is fixedly arranged at the top of the cover body 5, and a lower heat insulation screen 17 of a cylindrical structure is correspondingly arranged on the base 1 at the bottom, and the top of the lower heat insulation screen 17 extends into the inner side of the upper heat insulation screen 6. That is, the inner diameter of the upper heat insulation screen 6 is larger than the inner diameter of the lower heat insulation screen 17, and the heat insulation areas of the two intersect. Preferably, an air extraction port 22 is arranged in the middle of the base 1 inside the cover body 5, and an annular cooling cavity 21 is arranged along the outer side of the air extraction port 22.

[0027] The utility model lifts the cover body 5 through the lifting mechanism 2 so that the sample can be placed on the support seat 16; the hydraulic drive mechanism 10 drives the force transmission rod 14 and the upper pressure block 4 to rise and fall, so as to facilitate dynamic pressurization of the sample between the upper pressure block 4 and the support seat 16; the sintering temperature can be accurately controlled by the built-in heating mechanism and temperature measuring mechanism of the support seat 16, and secondly, under the action of the upper heat insulation screen 6 and the lower heat insulation screen 17, the temperature stability is improved, and the utility model has good practicality.

[0028] Embodiment 2:

[0029] A new type of carbonization furnace for bonding silicon carbide seed crystals, such as Figure 1-Figure 3 As shown, a cover body 5 is placed on a base 1 with sufficient mechanical strength, and a lifting ear 3 is designed on the side of the cover body 5. A lifting mechanism 2 is hung with the lifting ear 3, and the lifting mechanism 2 is used to lift the cover body 5. An air intake valve and a manual air release valve are installed on the top of the cover body 5. The air intake valve is used to control the external specific component gas (determined according to actual process requirements) to enter the cover body 5. The manual air release valve is used to balance the air pressure inside and outside the cover body 5, so as to facilitate the lifting of the cover body 5.

[0030] The top of the cover body 5 is opened, and a force transmission rod 14 connected to the telescopic bellows 8 is installed. The upper part of the force transmission rod 14 is connected to the top of the cover body 5 through the telescopic bellows 8. One end of the force transmission rod 14 is connected to the hydraulic drive mechanism 10, and the other end is connected to the upper pressing block 4. The force transmission rod 14 inside the cover body 5 is close to the side wall of one end of the telescopic bellows 8, and is surrounded by a metal cooling pipe 12. The water inlet and outlet of the metal cooling pipe 12 are connected to the cooling water system.

[0031] An upper heat shield 6 coaxial with the force transmission rod 14 is fixedly designed on the inner side of the upper part of the cover body 5, and a lower support seat 16 is installed on the base 1 on the inner side of the lower part of the cover body 5. The lower support seat 16 has a built-in heating mechanism and a temperature measuring mechanism. The heating mechanism and the temperature measuring thermocouple 18 are connected to the multi-core flange interface 19 on the base 1. In addition, a lower heat shield 17 is also designed on the base 1. The lower heat shield 17 is a cylindrical structure coaxial with the central axis of the cover body 5. The sample and sample mold assembly originally made at room temperature are placed between the lower support seat 16 and the upper pressing block 4.

[0032] The area where the cover 5 is projected on the base 1 is a circle. The central part of the base 1 in the circular area is provided with an air extraction port 22 connected to the vacuum system. An annular cooling cavity 21 is arranged outside the air extraction port 22. The water outlet and water inlet of the cooling cavity 21 are respectively connected to the cooling water system. In addition, a vacuum gauge interface 24 and a multi-core flange interface 19 are arranged on the base 1 in this circular area for realizing corresponding functional connections.

[0033] During the use of the utility model, first prepare the sample to be carbonized, then determine that the air pressure inside and outside the cover body 5 is equal, and control the lifting mechanism 2 so that the cover body 5 is raised to a height that is convenient for operation. Place the prepared sample and sample mold assembly at the center of the lower support seat 16. Control the lifting mechanism 2 so that the cover body 5 descends to a closed state. Close the manual inflation valve, open all cooling water, set the heating temperature (or the heating temperature multi-stage control program), set the hydraulic drive mechanism 10 (usually need to set the force loading value of different working stages, PLC control is more convenient), and start vacuum pumping. If it is necessary to introduce a specific gas, it is also necessary to control the air intake valve in time. After reaching the predetermined working time, turn off the heating, close the air intake valve (if necessary during the process), turn off the vacuum pump, monitor the temperature to close to room temperature, open the manual valve until the air pressure inside and outside the cover body 5 is balanced, control the lifting mechanism 2, so that the cover body 5 is lifted, and take out the carbonized sample and sample mold assembly. Clean the inside of the cover body 5 as necessary, and then control the lifting mechanism 2 so that the cover body 5 descends and closes. If necessary, start the vacuum pump again and shut it down after obtaining the necessary cavity vacuum.

[0034] Due to the differences in the physical and chemical processes occurring inside the sample at different carbonization stages, constant force application has limitations, which is not conducive to obtaining high-quality samples. The utility model drives the upper pressure block 4 to rise and fall through a hydraulic drive mechanism 10. Based on the hydraulic force application method, dynamic pressure adjustment of the entire process can be achieved through PLC control, avoiding the limitations of static pressure constant force of the pressure block, which is conducive to obtaining high-quality samples. Secondly, the utility model adopts an upper and lower two-layer heat shielding cover, which reduces the heat loss caused by thermal radiation in the sample heating area and overheating of the cover body 5, and effectively improves the temperature control and pressure control accuracy.

[0035] In the utility model, the force transmission rod 14 is connected to the housing 5 through the bellows 8, which ensures the stability of the vacuum degree inside the cavity during the working process and has a low possibility of leakage. In addition, the outer side of the integrally formed force transmission rod 14 is provided with cooling protection, which avoids the pressure inaccuracy and instability that may be caused by other force transmission methods.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A novel carbonization furnace for bonding silicon carbide seed crystals, characterized in that: The invention comprises a lifting mechanism (2), a base (1), a cover body (5) and a pressing tool. The cover body (5) is arranged on the top of the base (1). The lifting mechanism (2) is used to lift the cover body (5). The pressing tool comprises a linear drive mechanism, an upper pressing block (4) and a support seat (16). The linear drive mechanism is arranged on the top of the cover body (5). The driving end of the linear drive mechanism extends into the cover body (5) and is connected to the upper pressing block (4). The support seat (16) is arranged on the base (1) below the upper pressing block (4). A heating mechanism and a temperature measuring mechanism are arranged inside the support seat (16). An upper heat insulation screen (6) is arranged on the top of the cover body (5). A lower heat insulation screen (17) is arranged on the base (1) at the bottom of the cover body (5) outside the support seat (16). The lower heat insulation screen (17) is located on the inner side of the upper heat insulation screen (6).

2. A novel carbonization furnace for bonding silicon carbide seed crystals according to claim 1, characterized in that: The linear drive mechanism comprises a hydraulic drive mechanism (10) and a force transmission rod (14); the top of the cover body (5) is provided with the hydraulic drive mechanism (10), and the driving end of the hydraulic drive mechanism (10) is connected to the force transmission rod (14); one end of the force transmission rod (14) extends into the interior of the cover body (5) and is connected to the upper pressure block (4).

3. A novel carbonization furnace for bonding silicon carbide seed crystals according to claim 2, characterized in that: A bellows (8) is sleeved and installed on the outer side of the upper portion of the force transmission rod (14), and the force transmission rod (14) is connected to the top of the cover body (5) via the bellows (8).

4. A novel carbonization furnace for bonding silicon carbide seed crystals according to claim 3, characterized in that: A cooling mechanism is provided in the middle of the force transmission rod (14) located inside the cover body (5) along the length direction.

5. A novel carbonization furnace for bonding silicon carbide seed crystals according to claim 4, characterized in that: The cooling mechanism comprises a metal cooling pipe (12), and the metal cooling pipe (12) surrounds the middle part of the force transmission rod (14) along the length direction; the water inlet end and the water outlet end of the metal cooling pipe (12) respectively pass through the corrugated pipe (8) and extend out of the top of the cover body (5).

6. A novel carbonization furnace for bonding silicon carbide seed crystals according to any one of claims 1 to 5, characterized in that: An air intake valve and a manual air release valve are respectively arranged on both sides of the top of the cover body (5); an air extraction port (22) is arranged on the base (1) at the bottom of the cover body (5), and a cooling cavity (21) with an annular structure is arranged around the air extraction port (22); a water inlet and a water outlet are correspondingly arranged on the cooling cavity (21).

7. A novel carbonization furnace for bonding silicon carbide seed crystals according to claim 6, characterized in that: A vacuum gauge interface (24) and a multi-core flange interface (19) are also provided on the base (1) at the bottom inside the cover body (5).

8. The novel carbonization furnace for bonding silicon carbide seed crystals according to claim 1, characterized in that: A lifting ear (3) is provided on the outer side of the cover body (5), and a driving end of the lifting mechanism (2) slides through the base (1) and is connected to the lifting ear (3).

9. The novel carbonization furnace for bonding silicon carbide seed crystals according to claim 1, characterized in that: The upper heat insulation screen (6) and the lower heat insulation screen (17) are both cylindrical structures, and the top of the lower heat insulation screen (17) extends into the inner side of the upper heat insulation screen (6).

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