Rapid chemical vapor deposition equipment suitable for annular workpiece

Abstract

The rapid chemical vapor deposition equipment comprises a furnace body, a heat preservation layer arranged in the furnace body, a heater and an external power source, 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 utility model relates to the technical field of silicon carbide semiconductors, in particular to a rapid chemical vapor deposition device suitable for annular workpieces. Background Art

[0002] Chemical vapor infiltration (CVI) is a coating process that deposits a coating into the interior spaces of a porous preform under controlled conditions. The preform is placed in a dedicated CVI furnace, heated to the desired temperature under vacuum, and then a precursor gas composed of a specific ratio is introduced, where it pyrolyzes into differently charged ions that deposit on the pore surfaces, filling the pores within the preform. Because the matrix produced by CVI is tightly bonded to the preform fibers and has adjustable thickness, it is a preferred method for preparing high-performance carbon-carbon and carbon-ceramic composites.

[0003] Currently, commonly used CVI processes include isothermal CVI (ICVI), differential pressure CVI, thermal gradient CVI (TGCVI), forced flow CVI (FCVI), and direct heating CVI (HCVI). Electromagnetic field CVI (ECVI), based on ICVI, introduces an electromagnetic field. The electromagnetic field, generated by the hot process gas, produces beneficial mesophase charged ions. This field significantly promotes adsorption and capture of charged mesophase particles on the workpiece being deposited, accelerating deposition efficiency and shortening the composite material preparation cycle. ECVI is a promising low-cost, fast deposition CVI technology.

[0004] Currently, in medium-frequency induction heating deposition furnaces, an induction coil placed outside the insulation layer generates an alternating magnetic field under the action of alternating current. This induced current heats the induction crucible located inside the insulation layer within the furnace body, and heat is then transferred to the workpiece through radiation from the crucible. This induction coil is often wound around a hollow copper tube and has cooling water flowing through it. This induction coil heating device cannot be placed directly inside the furnace body, as it would be melted and damaged by the high temperatures inside the furnace. The magnetic field generated by this induction coil still needs to pass through the insulation layer and the induction crucible, weakening the induced electromagnetic field and limiting its effect on the movement of charged ions.

[0005] For annular workpieces, since there is a large hollow area in the central area, 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. Utility Model Content

[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 speed is low and the deposition quality on the inner and outer surfaces of the annular workpiece is inconsistent due to the long distance between the induced magnetic field and the workpiece.

[0007] The technical solution to the technical problem of the present invention is: constructing 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 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 that matches 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; it effectively prevents the process gas from contaminating the heater located 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 isolation barrel, and the cross-sectional shape of the sealing ring groove is set to be wedge-shaped to ensure reliable sealing between the inner isolation 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 to connect the spiral heater.

[0013] Furthermore, the current-inducing electrode includes an inner section located inside the insulation layer and extending to the inner side of the inner isolation barrel, and an outer section located between the outside 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 inside 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, a plurality of side air inlet nozzles passing through the intermediate insulation tube and the furnace body are fixedly provided on the outer isolation tube, and a plurality of bottom air inlet nozzles passing through the lower insulation cover are fixedly provided at the bottom of the furnace body, and the side air inlet nozzles and the bottom air inlet nozzles are connected to the external process air intake system.

[0017] The rapid chemical vapor deposition apparatus for annular workpieces disclosed herein has the following beneficial effects: By providing an inner and outer isolation barrel to form a deposition chamber, and positioning the heater within the inner isolation barrel, the space at the center of the annular workpiece is fully utilized, allowing the heater to be closer to the workpiece, reducing the heating space required, enabling rapid heating of the workpiece, and improving heating efficiency. By providing the inner and outer isolation barrels, a process gas flow path is formed between the inner and outer isolation barrels, further reducing the volume of the annular workpiece deposition chamber, improving process gas utilization, and effectively preventing process gas contamination of the heater. By configuring the heater in a spiral shape and electrically connecting it to an external medium- and high-frequency AC power source, the heater can generate heat itself and generate an alternating electromagnetic field that directly acts on the workpiece located outside the inner isolation barrel, generating alternating induction heating on the workpiece and accelerating the motion of ions in the process gas, thereby improving deposition efficiency. Furthermore, since the heater is positioned within the inner isolation barrel, further away from the insulation layer, the alternating electromagnetic field generated by the heater prevents the insulation layer from inducing currents and causing self-heating. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 2 Shown Figure 1 A magnified 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] It should also be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on 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 in the art of the present invention. The terms used herein in the specification of the present invention 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 a preferred embodiment of the rapid chemical vapor deposition equipment for annular workpieces described in the present invention, the equipment primarily comprises 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 tube 60. The insulation layer 20 is disposed within the furnace body 10, preferably in close proximity to the furnace body 10. The inner isolation barrel 50 is disposed at the center of the inner side of the insulation layer 20; the inner isolation barrel 50 is configured in a barrel shape with an opening 51 at one end, and the opening 51 is sealed at the bottom of the insulation layer 20 to form a sealed space within the inner isolation barrel 50. The heater 30 is disposed within the sealed space of the inner isolation barrel 50 and is electrically connected to the external power source 40. The heater 30 is preferably configured in a spiral shape that matches the inner wall of the inner isolation barrel 50, i.e., 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 positioned precisely within the inner isolation barrel 50 and does not contact the inner isolation barrel 50. An outer isolation barrel 60 is disposed on the inner sidewall of the insulation layer 20, and a deposition chamber 11 for processing the annular workpiece 1 is formed between the outer isolation barrel 60 and the inner isolation barrel 50. Preferably, the external power source 40 is a medium-high frequency AC power source. When the medium-high frequency AC power source is connected to the spiral heater 30, an alternating electromagnetic field T is formed around the heater 30. This alternating electromagnetic field T directly acts on the annular workpiece 1 located outside the inner isolation barrel 50, thereby increasing the heating rate of the annular workpiece 1 and promoting the rapid adsorption of charged ions in the intermediate phase on the surface of the annular workpiece 1, thereby increasing the deposition rate.

[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 just covers the top of the intermediate insulation tube 21; the lower insulation cover 23 can be provided on the inner side of the bottom of the furnace body 10, so that the lower insulation cover 23 just covers 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. Specifically, a sealing ring groove 23a can be provided on the top surface of the lower insulation cover 23. The sealing ring groove 23a matches the inner insulation barrel opening 51, so that the inner insulation barrel opening 51 just fits into 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 configured to be a spiral formed of graphite or a carbon-carbon composite material integrally molded. This ensures that the heater 30 will not fail due to high temperatures within the furnace body 10, and improves the heating efficiency of the heater 30. To ensure that the heater 30 is reliably supported at the center of the inner insulating barrel 50, a heater support leg 31 is preferably provided on the top surface of the lower insulation cover 23 at the center of the inner insulating barrel 50, and an insulating ceramic pad 32 is provided between the heater support leg 31 and the heater 30. Since the heater 30 is made of graphite or a carbon-carbon composite material, it is best to also provide insulating ceramic pads 32 between adjacent layers of the spiral heater 30 to ensure that the heater 30 is reliably positioned and not easily broken.

[0026] To facilitate wiring of the heater 30 within the inner insulating barrel 50, a current-drawing electrode 33 is preferably provided at the bottom of the furnace body 10, within the inner insulating barrel 50. One end of the current-drawing electrode 33 passes through the lower insulation cover 23 and is electrically connected to the heater 30, while the other end is electrically connected to the external power source 40. The current-drawing electrode is preferably divided into two sections, including an inner section 33a and an outer section 33b. The inner section 33a is embedded in the lower insulation cover 23 of the insulation layer 20 and extends into the inner side of the inner insulating barrel 50, electrically connecting to the heater 30 within the inner insulating barrel 50. The inner section 33a is preferably made of a high-temperature resistant material, such as graphite or a carbon-carbon composite material. The outer section 33b is fixed to the bottom of the furnace body 10 and disposed between the outer side of the lower insulation cover 23 and the furnace body 10, electrically connecting to the external power source 40. The outer section 33b is preferably made of a conductive metal material, such as a copper alloy.

[0027] In the above embodiment, an exhaust pipe 12 is preferably provided at the top of the furnace body 10. One end of the exhaust pipe 12 is connected to the external exhaust gas treatment system 2, while 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. The top 50a of the inner isolation barrel is preferably configured to be conical or frustum-shaped, with its rotation center A facing the exhaust pipe 12. This allows the exhaust gas in the deposition chamber 11 to smoothly enter the exhaust pipe 12 along the top 50a of the inner isolation barrel, ensuring stable gas flow in the deposition chamber 11 and preventing turbulence from affecting the deposition of the workpiece 1.

[0028] In the above embodiment, it is preferred that a plurality of side air inlet nozzles 3 are fixedly provided on the outer insulating tube 60, passing through the intermediate insulation tube 21 and the furnace body 10, and a plurality of bottom air inlet nozzles 4 are fixedly provided at the bottom of the furnace body 10, passing through the lower insulation cover 23. 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. 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 inner isolation barrel 50 and the outer isolation cylinder 60 may be made of graphite, carbon-carbon composite materials, or other ceramic materials.

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

Claims

1. A rapid chemical vapor deposition device suitable for an annular workpiece, comprising a furnace body, a heat-insulating layer disposed within the furnace body, a heater disposed within the furnace body, and an external power supply electrically connected to the heater, characterized in that: An inner isolation barrel is provided at the inner center 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 provided inside the inner isolation barrel; the heater is set in a spiral shape that matches 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 equipment for annular workpieces according to claim 1, characterized in that: The heater is a resistance heater made of graphite or carbon-carbon composite material.

3. The rapid chemical vapor deposition equipment 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 for annular workpieces according to claim 3, characterized in that: The top surface of the lower heat-insulating 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 porcelain 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 equipment 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 equipment 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, with its rotation center facing 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 fixed 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 fixed with a plurality of bottom air inlet nozzles passing through the lower insulation cover. The side air inlet nozzles and the bottom air inlet nozzles are connected to the external process air inlet system.

Images