Rapid chemical vapor deposition equipment suitable for annular workpiece

Abstract

The rapid chemical vapor deposition equipment comprises a furnace body, a heat preservation layer, a heater and an external power source, the heat preservation layer, the heater and the external power source are arranged in the furnace body, an inner isolation barrel is arranged in the center of the inner side of the heat preservation layer, and an outer isolation barrel is arranged on the inner side wall of the heat preservation layer; a deposition chamber used for machining the annular workpiece is formed between the outer isolation barrel and the inner isolation barrel, and the heater is arranged in the inner isolation barrel. The heater is spiral, and the external power supply is a medium-high frequency alternating current power supply. The deposition chamber is formed by arranging the inner isolation barrel and the outer isolation barrel, and the heater is arranged in the inner isolation barrel, so that the heating efficiency can be improved, and the utilization rate of process gas is increased. The spiral heater is arranged to be electrically connected with the external medium-high frequency alternating current power supply, on one hand, the heater can generate heat, on the other hand, an alternating electromagnetic field generated by the heater can generate alternating induction heating on a workpiece, the movement speed of electric ions in process gas can be increased, and therefore the deposition efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide semiconductors, and in particular to a rapid chemical vapor deposition device suitable for an annular workpiece. Background Art

[0002] The chemical vapor infiltration (CVI) process is a coating process that deposits coatings into the internal space of a porous preform under controlled conditions. The process is to place the preform in a special CVI furnace, heat it to the required temperature under vacuum, and introduce a precursor gas composed of a specific ratio to pyrolyze it into different charged ions and deposit them on the pore surface to fill the pores in the preform. Since the matrix prepared by CVI is tightly combined with the preform fiber and the structure thickness is adjustable, it is the preferred method for preparing high-performance carbon-carbon, carbon-ceramic and other composite materials.

[0003] At present, the commonly used CVI processes include isothermal CVI (ICVI), differential pressure CVI, thermal gradient CVI (TGCVI), forced flow CVI (FCVI), direct heating CVI (HCVI), etc., and electromagnetic field CVI (ECVI) introduces electromagnetic field on the basis of ICVI. The process gas produces beneficial intermediate phase charged ions under hot conditions. The electromagnetic field can greatly promote the adsorption of the workpiece to be deposited and capture the intermediate phase charged particles, so that the deposition efficiency is accelerated and the preparation cycle of the composite material is shortened. It is a low-cost and fast deposition CVI technology with great application prospects.

[0004] At present, in medium frequency induction heating deposition furnaces, the induction coil set on the outside of the insulation layer generally generates an alternating magnetic field under the action of alternating current to generate an induced current to heat the induction crucible located inside the insulation layer in the furnace body, and transfer heat to the workpiece through the crucible radiation. This induction coil is mostly wound with a hollow copper tube, and cooling water is passed inside; this induction coil heating device cannot be directly set inside the furnace body, otherwise it will be melted and damaged by the high temperature in the furnace. The magnetic field generated by this induction coil still needs to pass through the insulation layer and the induction crucible, the induced electromagnetic field strength is weakened, and the effect on the movement of charged ions is also limited.

[0005] For annular workpieces, since there is a large hollow area in the central region, the diffusion space of the process gas is large during deposition, resulting in a relatively small probability of the intermediate phase charged ions after the pyrolysis of the process gas adhering to the inner surface of the annular workpiece. Most of them are discharged with the exhaust gas, resulting in low gas utilization and inconsistent deposition quality. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a rapid chemical vapor deposition device suitable for annular workpieces, aiming at the problem that in the medium-frequency induction heating vapor deposition furnace in the prior art, the deposition rate is low and the deposition quality on the inner and outer surfaces of the annular workpiece is inconsistent due to the long distance of the induced magnetic field from the workpiece.

[0007] The technical solution to the technical problem of the present invention is: construct a rapid chemical vapor deposition device suitable for annular workpieces, including a rapid chemical vapor deposition device suitable for annular workpieces, including a furnace body, an insulation layer arranged in the furnace body, a heater arranged in the furnace body and an external power supply electrically connected to the heater, an inner isolation barrel is provided at the center position of the inner side of the insulation layer, and the inner isolation barrel is open and sealed at the bottom of the insulation layer; an outer isolation barrel is provided on the inner wall of the insulation layer, and a deposition chamber for processing annular workpieces is formed between the outer isolation barrel and the inner isolation barrel; the heater is arranged inside the inner isolation barrel; the heater is arranged in a spiral shape matching the inner wall of the inner isolation barrel, and the external power supply is a medium and high frequency AC power supply.

[0008] Furthermore, the heater is a resistance heater made of graphite or carbon-carbon composite material in one piece, so that the resistance heater itself can withstand the heat preservation environment in the furnace body.

[0009] Furthermore, the insulation layer includes an intermediate insulation tube arranged on the inner wall of the furnace body, an upper insulation cover arranged on the top of the intermediate insulation tube, and a lower insulation cover arranged on the bottom of the intermediate insulation tube, and the inner isolation barrel is open and sealed on the top surface of the lower insulation cover, effectively preventing the process gas from contaminating the heater in the inner isolation barrel during the deposition process.

[0010] Furthermore, the top surface of the lower insulation cover is provided with a sealing ring groove matching the opening of the inner insulation barrel, and the cross-sectional shape of the sealing ring groove is set to be wedge-shaped to ensure reliable sealing between the inner insulation barrel and the lower insulation cover.

[0011] Furthermore, a heater support foot is provided at the center of the inner isolation barrel at the lower insulation cover, and an insulating ceramic pad is provided between the heater and the heater support foot to ensure that the spiral heater can be effectively supported during operation.

[0012] Furthermore, a power-inducing electrode is provided at the bottom of the furnace body inside the inner isolation barrel, one end of the power-inducing electrode passes through the lower insulation cover and is electrically connected to the heater, while the other end is electrically connected to the external power supply so as to connect the spiral heater.

[0013] Furthermore, the current-inducing electrode includes an inner section located in the insulation layer and extending to the inner side of the inner isolation barrel, and an outer section located between the outer side of the insulation layer and the furnace body. The inner section is made of high-temperature resistant material, and the outer section is made of metal conductive material to ensure that the inner section can withstand the high temperature environment in the insulation layer.

[0014] Furthermore, an exhaust pipe is provided on the top of the furnace body, one end of the exhaust pipe is connected to an external exhaust gas treatment system, and the other end passes through the upper insulation cover and is connected to the top of the inner isolation barrel.

[0015] Furthermore, the top of the inner isolation barrel is configured to be conical or truncated cone-shaped, with its rotation center facing the exhaust pipe, so as to facilitate the diversion of the exhaust gas.

[0016] Furthermore, the outer isolation tube is fixedly provided with a plurality of side air inlet nozzles passing through the middle insulation tube and the furnace body, and the bottom of the furnace body is fixedly provided with a plurality of bottom air inlet nozzles passing through the lower insulation cover, and the side air inlet nozzles and the bottom air inlet nozzles are connected to an external process air inlet system.

[0017] The rapid chemical vapor deposition equipment for annular workpieces according to the present invention has the following beneficial effects: by setting an inner isolation barrel and an outer isolation barrel to form a deposition chamber, and setting a heater inside the inner isolation barrel, the space at the center of the annular workpiece is fully utilized, so that the heater is close to the workpiece, the heating space is reduced, the workpiece can be quickly heated, and the heating efficiency is improved. By setting an inner isolation barrel and an outer isolation barrel, a process gas flow channel is formed between the inner isolation barrel and the outer isolation barrel, the volume of the annular workpiece deposition chamber is further reduced, the utilization rate of the process gas is improved, and the contamination of the heater by the process gas is effectively prevented. By setting the heater in a spiral shape and electrically connecting it to an external medium and high frequency AC power supply, on the one hand, the heater itself can generate heat, and on the other hand, the heater can generate an alternating electromagnetic field, which directly acts on the workpiece located outside the inner isolation barrel, which can not only generate alternating induction heating on the workpiece, but also accelerate the movement speed of ions in the process gas, thereby improving the deposition efficiency. At the same time, since the heater is set on the inner side of the inner isolation barrel and is far away from the insulation layer, it is avoided that the alternating electromagnetic field generated by the heater generates an induced current on the insulation layer, resulting in self-heating of the insulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a preferred embodiment of the rapid chemical vapor deposition equipment applicable to annular workpieces according to the present invention;

[0019] Figure 2 Shown Figure 1 Enlarged view of part I. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

[0021] It should also be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0023] like Figure 1 , 2 As shown, in the preferred embodiment of the rapid chemical vapor deposition device suitable for annular workpieces of the present invention, it mainly includes a furnace body 10, an insulation layer 20, a heater 30, an external power source 40, an inner isolation barrel 50 and an outer isolation barrel 60. The insulation layer 20 is arranged in the furnace body 10, preferably close to the furnace body 10. The inner isolation barrel 50 is arranged at the center of the inner side of the insulation layer 20; the inner isolation barrel 50 is arranged in a barrel shape with an open end 51, and its open end 51 is sealed at the bottom of the insulation layer 20, so as to form a closed space inside the inner isolation barrel 50. The heater 30 is arranged in the closed space of the inner isolation barrel 50 and is electrically connected to the external power source 40. Preferably, the heater 30 is arranged in a spiral shape matching the inner side wall of the inner isolation barrel 50, that is, the outer contour of the spiral heater 30 is slightly smaller than the inner diameter of the inner isolation barrel 50, so that the spiral heater 30 is just located in the inner isolation barrel 50 and does not contact the inner isolation barrel 50. The outer isolation tube 60 is arranged on the inner wall of the insulation layer 20, and a deposition chamber 11 for processing the annular workpiece 1 is formed between the outer isolation tube 60 and the inner isolation barrel 50. Preferably, the external power supply 40 is set to be a medium-high frequency AC power supply. When the medium-high frequency AC power supply is connected to the spiral heater 30, an alternating electromagnetic field T is formed around the heater 30. The alternating electromagnetic field T directly acts on the annular workpiece 1 located outside the inner isolation barrel 50, which can not only improve the heating speed of the annular workpiece 1, but also promote the rapid adsorption of the intermediate phase charged ions on the surface of the annular workpiece 1, thereby improving the deposition speed.

[0024] In this preferred embodiment, the insulation layer 20 is preferably provided to include an intermediate insulation tube 21, an upper insulation cover 22 and a lower insulation cover 23. Specifically, the intermediate insulation tube 21 can be provided on the inner side wall of the furnace body 10, and the upper insulation cover 22 can be provided on the inner side of the top of the furnace body 10, so that the upper insulation 22 is just covered on the top of the intermediate insulation tube 21; the lower insulation cover 23 is provided on the inner side of the bottom of the furnace body 10, so that the lower insulation cover 23 is just covered on the bottom of the intermediate insulation tube 21. The inner insulation barrel opening 51 is provided on the top surface of the lower insulation cover 23, and specifically, a sealing ring groove 23a can be provided on the top surface of the lower insulation cover 23, and the sealing ring groove 23a matches the inner insulation barrel opening 51, so that the inner insulation barrel opening 51 is just embedded in the sealing ring groove 23a. It is best to set the cross-sectional shape of the sealing ring groove 23a to a wedge shape so that the inner isolation barrel opening 51 can be inserted tighter and tighter along the groove wall of the sealing ring groove 23a to ensure that the inner isolation barrel 50 can be sealed on the top surface of the lower insulation cover 23.

[0025] In this preferred embodiment, the heater 30 is preferably set to be a spiral shape made of graphite or carbon-carbon composite material integrally formed. On the one hand, it can ensure that the heater 30 will not fail due to high temperature in the furnace body 10, and on the other hand, it can improve the heating efficiency of the heater 30. In order to ensure that the heater 30 is reliably supported at the center of the inner isolation barrel 50, it is preferred to set a heater support foot 31 on the top surface of the lower insulation cover 23 at the center of the inner isolation barrel 50, and set an insulating ceramic pad 32 between the heater support foot 31 and the heater 30; since the heater 30 is made of graphite or carbon-carbon composite material, it is best to also set an insulating ceramic pad 32 between adjacent layers of the spiral heater 30 to ensure that the heater 30 is reliably positioned and not easily broken.

[0026] In order to facilitate the wiring of the heater 30 located in the inner isolation barrel 50, it is preferred to set a lead electrode 33 at the bottom of the furnace body 10 in the inner area of ​​the inner isolation barrel 50, one end of the lead electrode 33 passes through the lower insulation cover 23 to be electrically connected to the heater 30, and the other end is electrically connected to the external power supply 40. It is best to divide the lead electrode into two sections, including an inner section 33a and an outer section 33b, wherein the inner section 33a is embedded in the lower insulation cover 23 of the insulation layer 20 and extends to the inner side of the inner isolation barrel 50, and is electrically connected to the heater 30 located in the inner isolation barrel 50. It is preferred to set the inner section 33a to be made of high temperature resistant material, such as graphite, carbon-carbon composite material, etc. The outer section 33b is fixed to the bottom of the furnace body 10 and is set between the outer side of the lower insulation cover 23 and the furnace body 10, and is electrically connected to the external power supply 40. It is preferred to set the outer section 33b to be made of metal conductive material, such as copper alloy, etc.

[0027] In the above embodiment, it is preferred to set an exhaust pipe 12 on the top of the furnace body 10, one end of the exhaust pipe 12 is connected to the external exhaust gas treatment system 2, and the other end passes through the upper insulation cover 22 and is connected to the top of the inner isolation barrel 50, so that the exhaust gas in the deposition chamber 11 can be discharged to the exhaust gas treatment system 2 for treatment through the exhaust pipe 12. It is preferred to set the top 50a of the inner isolation barrel to a conical or truncated cone shape, and its rotation center A is directly opposite to the exhaust pipe 12, so that the exhaust gas in the deposition chamber 11 can smoothly enter the exhaust pipe 12 along the top 50a of the inner isolation barrel, ensuring that the gas field flow in the deposition chamber 11 is stable and does not generate turbulence to affect the deposition of the workpiece 1.

[0028] In the above embodiment, it is preferred that a plurality of side air inlet nozzles 3 passing through the middle insulation tube 21 and the furnace body 10 are fixedly arranged on the outer isolation tube 60, and a plurality of bottom air inlet nozzles 4 passing through the lower insulation cover 23 are fixedly arranged at the bottom of the furnace body 10. Both the side air inlet nozzles 3 and the bottom air inlet nozzles 4 are connected to the external process air inlet system 5 to ensure a stable supply of process gas to the deposition chamber 11. In this way, on the one hand, the process gas enters the deposition chamber 11 from the bottom air inlet nozzle 4 at the bottom of the furnace body and is evenly dispersed on the inner and outer surfaces of the annular workpiece 1, and on the other hand, the side air inlet nozzles 3 can replenish fresh process gas in the height direction to ensure consistent deposition quality at all heights of the annular workpiece 1.

[0029] In the above embodiment, the material of the inner isolation barrel 50 and the outer isolation barrel 60 may be graphite or a carbon-carbon composite material or other ceramic materials.

[0030] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work, any modifications, equivalent substitutions, improvements, etc. made should be included in the protection scope of the present invention.

Claims

1. A rapid chemical vapor deposition device suitable for an annular workpiece, comprising a furnace body, a heat preservation layer arranged in the furnace body, a heater arranged in the furnace body, and an external power supply electrically connected to the heater, characterized in that: An inner isolation barrel is provided at the center position of the inner side of the insulation layer, and the inner isolation barrel is open and sealed and arranged at the bottom of the insulation layer; an outer isolation barrel is provided on the inner wall of the insulation layer, and a deposition chamber for processing annular workpieces is formed between the outer isolation barrel and the inner isolation barrel; the heater is arranged inside the inner isolation barrel; the heater is set in a spiral shape matching the inner wall of the inner isolation barrel, and the external power supply is a medium and high frequency AC power supply.

2. The rapid chemical vapor deposition device suitable for annular workpieces according to claim 1, characterized in that: The heater is a resistance heater made of graphite or carbon-carbon composite material integrally formed.

3. The rapid chemical vapor deposition equipment suitable for annular workpieces according to claim 1, characterized in that: The insulation layer includes an intermediate insulation tube arranged on the inner wall of the furnace body, an upper insulation cover arranged on the top of the intermediate insulation tube, and a lower insulation cover arranged on the bottom of the intermediate insulation tube. The inner isolation barrel is open and sealed on the top surface of the lower insulation cover.

4. The rapid chemical vapor deposition equipment suitable for annular workpieces according to claim 3, characterized in that: The top surface of the lower insulation cover is provided with a sealing ring groove matching the opening of the inner isolation barrel, and the cross-sectional shape of the sealing ring groove is set to be wedge-shaped.

5. The rapid chemical vapor deposition equipment suitable for annular workpieces according to claim 3, characterized in that: A heater support foot is provided at the center of the inner isolation barrel at the lower heat-insulating cover, and an insulating ceramic pad is provided between the heater and the heater support foot.

6. The rapid chemical vapor deposition equipment suitable for annular workpieces according to claim 3, characterized in that: The bottom of the furnace body is located inside the inner isolation barrel and is provided with an electric lead electrode, one end of the electric lead electrode passes through the lower insulation cover and is electrically connected to the heater, while the other end is electrically connected to the external power supply.

7. The rapid chemical vapor deposition device suitable for annular workpieces according to claim 6, characterized in that: The current-inducing electrode includes an inner section located in the insulation layer and extending to the inner side of the inner isolation barrel, and an outer section located between the outer side of the insulation layer and the furnace body. The inner section is made of high-temperature resistant material, and the outer section is made of metal conductive material.

8. The rapid chemical vapor deposition device suitable for annular workpieces according to any one of claims 3 to 7, characterized in that: An exhaust pipe is provided on the top of the furnace body, one end of the exhaust pipe is connected to an external tail gas treatment system, and the other end passes through the upper insulation cover and is connected to the top of the inner isolation barrel.

9. The rapid chemical vapor deposition device suitable for annular workpieces according to claim 8, characterized in that: The top of the inner isolation barrel is configured to be conical or truncated cone-shaped, and its rotation center faces the exhaust pipe.

10. The rapid chemical vapor deposition equipment suitable for annular workpieces according to claim 3, characterized in that: The outer isolation tube is fixedly provided with a plurality of side air inlet nozzles passing through the middle insulation tube and the furnace body, and the bottom of the furnace body is fixedly provided with a plurality of bottom air inlet nozzles passing through the lower insulation cover, and the side air inlet nozzles and the bottom air inlet nozzles are connected to an external process air inlet system.

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