阅读说明：本技术 一种提高cvd法碳化硅沉积炉利用率的热场结构及工艺方法 (Thermal field structure and technological method for improving utilization rate of CVD silicon carbide deposition furnace ) 是由 韩科选 薛赓 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种提高CVD法碳化硅沉积炉利用率的热场结构及工艺方法,涉及无机非金属材料技术领域,包括炉壳,所述炉壳底部固定连接有载物旋转机构,炉壳内壁底部两侧均固定连接有底部支撑柱,底部支撑柱顶部固定连接有底部支撑板,底部支撑板顶部固定连接有保温层,保温层内壁下方两侧均固定连接有底部加热系统,载物旋转机构的输出端固定连接有转动轴,转动轴与炉壳和保温层的底部转动连接,转动轴顶部固定连接有载物台,载物台顶部设置有载物盘,载物盘表面开设有若干个限流孔,载物盘的边缘通过限流孔滑动连接支撑杆,支撑杆表面等间距滑动连接有若干个载物盘。本发明通过设置载物旋转机构,提升原料气利用率。(The invention discloses a thermal field structure for improving the utilization rate of a CVD silicon carbide deposition furnace and a process method thereof, relating to the technical field of inorganic nonmetallic materials and comprising a furnace shell, stove outer covering bottom fixedly connected with carries thing rotary mechanism, the equal fixedly connected with bottom sprag post in stove outer covering inner wall bottom both sides, bottom sprag post top fixedly connected with bottom sprag post, bottom sprag post top fixedly connected with heat preservation, the equal fixedly connected with bottom heating system in heat preservation inner wall below both sides, the output fixedly connected with axis of rotation that carries thing rotary mechanism, the axis of rotation is rotated with the bottom of stove outer covering and heat preservation and is connected, axis of rotation top fixedly connected with objective table, the objective table top is provided with carries the thing dish, a plurality of restricted aperture has been seted up to the objective table surface, the edge of carrying the thing dish passes through restricted aperture sliding connection bracing piece, equidistant sliding connection has a plurality of to carry the thing dish on the bracing piece surface. The invention improves the utilization rate of the raw material gas by arranging the carrying rotary mechanism.)

1. The thermal field structure for improving the utilization rate of the CVD silicon carbide deposition furnace is characterized by comprising a furnace shell (1), wherein a carrying rotary mechanism (3) is fixedly connected to the bottom of the furnace shell (1), bottom supporting columns (4) are fixedly connected to two sides of the bottom of the inner wall of the furnace shell (1), bottom supporting plates (5) are fixedly connected to the tops of the bottom supporting columns (4), a heat preservation layer (2) is fixedly connected to the tops of the bottom supporting plates (5), a bottom heating system (6) is fixedly connected to two sides below the inner wall of the heat preservation layer (2), a rotating shaft is fixedly connected to the output end of the carrying rotary mechanism (3), the rotating shaft is rotatably connected with the bottoms of the furnace shell (1) and the heat preservation layer (2), a carrying table (7) is fixedly connected to the top of the rotating shaft, a carrying disc (8) is arranged on the top of the carrying table (7), and a plurality of flow limiting holes (801) are formed in the surface of the carrying disc (8), the edge of carrying dish (8) has bracing piece (13) through restricted aperture (801) sliding connection, bracing piece (13) surface equidistant sliding connection has a plurality of to carry dish (8), bracing piece (13) and the handing-over department threaded connection of carrying dish (8) have lock nut (14), carry on fixed surface and be connected with a plurality of supporter (12) on dish (8), supporter (12) top fixedly connected with work piece (9).

2. The thermal field structure for improving the utilization rate of the CVD-method silicon carbide deposition furnace according to claim 1, characterized in that: the middle of the inner wall of the heat-insulating layer (2) is fixedly connected with a plurality of flow blocking rings (11).

3. The thermal field structure for improving the utilization rate of the CVD-method silicon carbide deposition furnace according to claim 1, characterized in that: the left side, the right side and the bottom of the heat preservation layer (2) are fixedly connected with a plurality of communicating pipes, and the tail ends of the communicating pipes are fixedly connected with air inlet nozzles (10).

4. The thermal field structure for improving the utilization rate of the CVD-method silicon carbide deposition furnace according to claim 1, characterized in that: and the top of the heat-insulating layer (2) is provided with a plurality of exhaust ports (15).

5. The thermal field structure for improving the utilization rate of the CVD-method silicon carbide deposition furnace according to claim 1, characterized in that: the flow limiting holes (801) are arranged at equal intervals according to the circumference of the object carrying disc (8), and the support rods (13) are arranged at equal intervals according to the circumference of the object carrying disc (8).

6. The thermal field structure for improving the utilization rate of the CVD-method silicon carbide deposition furnace according to claim 1, characterized in that: the workpiece (9) is in the shape of a circular truncated cone.

7. A process method of a thermal field structure for improving the utilization rate of a CVD silicon carbide deposition furnace is characterized by comprising the following steps:

s101: vacuumizing: putting the workpiece (9) on a carrying disc (8), closing the furnace, vacuumizing to ensure that the vacuum degree of a reaction furnace chamber is not more than 100 pa;

s102: and (3) leak detection: closing the gas outlet valve, introducing inert protective gas (argon, nitrogen and helium) into the furnace at the flow rate of 100L/min, backfilling the pressure in the furnace to about 10Kpa, then pumping gas to be less than or equal to 100pa according to the step S101, circulating for 2-3 times, and then performing leak detection, wherein the leak rate is less than or equal to 1mbarl/5 min;

s103: heating: after the leakage detection is qualified, starting a heating device of a reaction furnace chamber, heating the reaction chamber to 600-800 ℃, continuously introducing inert protective gas into the furnace at a flow rate of 100-200L/min, keeping the vacuum degree in the furnace to 80-110 Kpa, continuously heating to 1200-1400 ℃, and controlling the temperature of a bottom heating system (6) to be 300-500 ℃;

s104: and (3) raw material gas deposition: the reaction chamber is maintained at 1200-1400 ℃ for 2-3 h, a v1 valve is opened to start feeding raw material gas MTS (methyl trichlorosilane) into the furnace, the raw material gas enters in a dilution gas hydrogen bubbling mode, and deposition is carried out for 4-10 h at the temperature; raw material gas enters the furnace through a v1 valve by f1 and f2, the raw material gas is preheated to 300-500 ℃ in the area of a bottom heating system (6), the heated raw material gas enters the reaction chamber by f3 from a bottom thermal field and by f4 from the side;

s105: cooling: after the reaction is finished, stopping introducing the raw material gas and starting cooling, and continuously introducing inert gas at the flow rate of 100-200L/min; after the temperature is reduced to 200 ℃, stopping introducing the inert gas, starting vacuumizing to be less than or equal to 100Pa, and refilling the inert gas to 100 Kpa;

s106: discharging: after the temperature is reduced to 50 ℃, the workpiece (9) can be taken out.

Technical Field

The invention relates to the technical field of inorganic nonmetallic materials, in particular to a thermal field structure and a process method for improving the utilization rate of a CVD silicon carbide deposition furnace.

Background

At present, because graphite parts in a semiconductor single crystal furnace are in a high-temperature silicon steam atmosphere for a long time, silicon materials and some volatile impurities in a crucible are easy to be adsorbed on the graphite, and the minority carrier lifetime of a crystal bar is low due to long time. Particularly, the guide cylinder for producing the N-type single crystal is used after 3-4 furnaces are used and need to be purified once, and the use cost is high. To solve the above problems, a thin layer of silicon carbide may be deposited on the graphite surface using a Chemical Vapor Deposition (CVD) process, and the coating may improve product quality and improve process efficiency, thereby reducing the overall operating cost of the customer. The coating extends the service life of the graphite component and realizes the high-purity surface structure required by the production of the silicon single crystal. The high-purity silicon carbide (SiC) material has a series of excellent performances of low density, high temperature resistance, oxidation resistance, scouring resistance, corrosion resistance and the like, and is an ideal material system for the surface protective coating of the graphite material.

The traditional preparation method is to directly deposit a SiC coating on the graphite surface by adopting a Chemical Vapor Deposition (CVD) or brushing method, but the problems of poor uniformity of a gas field, uneven workpiece coating and low utilization rate of raw material gas exist. In order to solve the above problems, it is necessary to provide a thermal field structure and a process method for improving the utilization rate of a CVD silicon carbide deposition furnace.

Disclosure of Invention

In order to solve the technical problems, the technical scheme solves the problems that the traditional preparation method provided in the background art usually adopts a Chemical Vapor Deposition (CVD) or brushing method to directly deposit a SiC coating on the graphite surface, but the gas field uniformity is poor, the workpiece coating is uneven and the utilization rate of raw material gas is low.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

a thermal field structure for improving the utilization rate of a CVD silicon carbide deposition furnace comprises a furnace shell, wherein the bottom of the furnace shell is fixedly connected with a carrying rotary mechanism, two sides of the bottom of the inner wall of the furnace shell are fixedly connected with bottom support columns, the tops of the bottom support columns are fixedly connected with a bottom support plate, the top of the bottom support plate is fixedly connected with a heat preservation layer, two sides below the inner wall of the heat preservation layer are fixedly connected with a bottom heating system, the output end of the carrying rotary mechanism is fixedly connected with a rotary shaft, the rotary shaft is rotatably connected with the bottoms of the furnace shell and the heat preservation layer, the top of the rotary shaft is fixedly connected with a carrying platform, the top of the carrying platform is provided with a carrying disc, the surface of the carrying disc is provided with a plurality of flow limiting holes, the edge of the carrying disc is slidably connected with a support rod through the flow limiting holes, the surface of the support rod is equidistantly and slidably connected with a plurality of carrying discs, and a locking nut is in threaded connection with the joint of the support rod and the carrying disc, the upper surface of the carrying plate is fixedly connected with a plurality of article placing frames, and the tops of the article placing frames are fixedly connected with workpieces.

Preferably, a plurality of flow blocking rings are fixedly connected in the middle of the inner wall of the heat insulation layer.

Preferably, the left side, the right side and the bottom of the heat preservation layer are fixedly connected with a plurality of communicating pipes, and the tail ends of the communicating pipes are fixedly connected with air inlet nozzles.

Preferably, a plurality of exhaust ports are formed in the top of the heat insulation layer.

Preferably, the flow limiting holes are arranged at equal intervals according to the circumference of the object carrying disc, and the support rods are arranged at equal intervals according to the circumference of the object carrying disc.

Preferably, the workpiece is in the shape of a truncated cone.

Further, a process method for the thermal field structure for improving the utilization rate of the CVD silicon carbide deposition furnace is provided, and comprises the following steps:

s101: vacuumizing: putting the workpiece on a carrying disc, closing the furnace, vacuumizing to ensure that the vacuum degree of a reaction furnace chamber is not more than 100 pa;

s102: and (3) leak detection: closing the gas outlet valve, introducing inert protective gas (argon, nitrogen and helium) into the furnace at the flow rate of 100L/min, backfilling the pressure in the furnace to about 10Kpa, then pumping gas to be less than or equal to 100pa according to the step S101, circulating for 2-3 times, and then performing leak detection, wherein the leak rate is less than or equal to 1mbarl/5 min;

s103: heating: after the leakage detection is qualified, starting a heating device of a reaction furnace chamber, heating the reaction chamber to 600-800 ℃, continuously introducing inert protective gas into the furnace at a flow rate of 100-200L/min, keeping the vacuum degree in the furnace to 80-110 Kpa, continuously heating to 1200-1400 ℃, and controlling the temperature of a bottom heating system to 300-500 ℃;

s104: and (3) raw material gas deposition: the reaction chamber is maintained at 1200-1400 ℃ for 2-3 h, a v1 valve is opened to start feeding raw material gas MTS (methyl trichlorosilane) into the furnace, the raw material gas enters in a dilution gas hydrogen bubbling mode, and deposition is carried out for 4-10 h at the temperature; the method comprises the following steps that raw material gas enters a furnace through a v1 valve in two paths of f1 and f2, the raw material gas is preheated to 300-500 ℃ in a bottom heating system area, the heated raw material gas enters the f3 from a bottom thermal field, and the heated raw material gas enters a reaction chamber from the side part of the f 4;

s105: cooling: after the reaction is finished, stopping introducing the raw material gas and starting cooling, and continuously introducing inert gas at the flow rate of 100-200L/min; after the temperature is reduced to 200 ℃, stopping introducing the inert gas, starting vacuumizing to be less than or equal to 100Pa, and refilling the inert gas to 100 Kpa;

s106: discharging: and after the temperature is reduced to 50 ℃, taking out the workpiece.

Compared with the prior art, the invention provides a thermal field structure and a process method for improving the utilization rate of a CVD silicon carbide deposition furnace, and the thermal field structure and the process method have the following beneficial effects:

1. the object carrying rotating mechanism is arranged to rotate the workpiece, so that the raw material gas is in more sufficient contact with the workpiece, and the flow limiting hole in the object carrying rotating mechanism can effectively limit the flow speed of the raw material gas, so that the residence time of the raw material gas in the reaction chamber is longer, and the utilization rate of the raw material gas is improved;

2. through setting up air inlet nozzle, a plurality of air inlet nozzle of circumference equipartition are followed to the heat preservation bottom, and the inside side of heat preservation vertically divides 3 ~ 5 layers along a plurality of air inlet nozzle of circumference equipartition, and a plurality of air inlet nozzle can fully spray the feed gas at the work piece, increases near work piece feed gas concentration that upper portion ramds and adds, and the feed gas keeps off through keeping off the discharge ring and can form the vortex and increase the detention time at the reaction chamber, it can make the feed gas utilization ratio higher to go up the thermal field structure, the coating is more even.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic isometric view of a workpiece according to the present invention;

FIG. 3 is a front view of a workpiece according to the present invention;

FIG. 4 is a schematic top view of a workpiece according to the present invention;

fig. 5 is a schematic view of the structure of the objective table of the present invention.

The reference numbers in the figures are:

1. a furnace shell; 2. a heat-insulating layer; 3. a carrying and rotating mechanism; 4. a bottom support column; 5. a bottom support plate; 6. a bottom heating system; 7. an object stage;

8. a carrying tray; 801. a flow restriction orifice;

9. a workpiece; 10. an air inlet nozzle; 11. a flow blocking ring; 12. a rack; 13. a support bar; 14. locking the nut; 15. and (7) an exhaust port.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

Referring to fig. 1-5, a thermal field structure for improving the utilization rate of a silicon carbide deposition furnace by a CVD method comprises a furnace shell 1, wherein a carrying rotary mechanism 3 is fixedly connected to the bottom of the furnace shell 1, bottom support columns 4 are fixedly connected to both sides of the bottom of the inner wall of the furnace shell 1, a bottom support plate 5 is fixedly connected to the top of each bottom support column 4, a heat insulation layer 2 is fixedly connected to the top of each bottom support plate 5, a bottom heating system 6 is fixedly connected to both sides of the lower portion of the inner wall of each heat insulation layer 2, a rotary shaft is fixedly connected to the output end of the carrying rotary mechanism 3 and is rotatably connected to the bottom of the furnace shell 1 and the heat insulation layer 2, a carrying table 7 is fixedly connected to the top of the rotary shaft, a carrying disc 8 is arranged on the top of the carrying table 7, a plurality of flow limiting holes 801 are formed in the surface of the carrying disc 8, a support rod 13 is slidably connected to the edge of the carrying disc 8 through the flow limiting holes 801, a plurality of carrying discs 8 are slidably connected to the surface of the support rod 13 at equal intervals, the supporting rod 13 is in threaded connection with the joint of the object carrying plate 8 through a locking nut 14, the upper surface of the object carrying plate 8 is fixedly connected with a plurality of object placing frames 12, and the tops of the object placing frames 12 are fixedly connected with workpieces 9.

Specifically, a plurality of flow blocking rings 11 are fixedly connected in the middle of the inner wall of the heat preservation layer 2.

The equal fixedly connected with a plurality of communicating pipe in heat preservation 2 left and right sides and bottom, communicating pipe end fixedly connected with air inlet nozzle 10.

The top of the heat-insulating layer 2 is provided with a plurality of exhaust ports 15.

The flow-limiting holes 801 are arranged at equal intervals along the circumference of the object carrying disc 8, and the support rods 13 are arranged at equal intervals along the circumference of the object carrying disc 8.

The workpiece 9 is shaped like a truncated cone.

Further, a process method for the thermal field structure for improving the utilization rate of the CVD silicon carbide deposition furnace is provided, and comprises the following steps:

s101: vacuumizing: putting the workpiece 9 on the carrying disc 8, and vacuumizing to ensure that the vacuum degree of the reaction furnace chamber is less than or equal to 100pa after furnace combination;

s102: and (3) leak detection: closing the gas outlet valve, introducing inert protective gas (argon, nitrogen and helium) into the furnace at the flow rate of 100L/min, backfilling the pressure in the furnace to about 10Kpa, then pumping gas to be less than or equal to 100pa according to the step S101, circulating for 2-3 times, and then performing leak detection, wherein the leak rate is less than or equal to 1mbarl/5 min;

s103: heating: after the leakage detection is qualified, starting a heating device of a reaction furnace chamber, heating the reaction chamber to 600-800 ℃, continuously introducing inert protective gas into the furnace at a flow rate of 100-200L/min, keeping the vacuum degree in the furnace to 80-110 Kpa, continuously heating to 1200-1400 ℃, and controlling the temperature of a bottom heating system 6 to be 300-500 ℃;

s104: and (3) raw material gas deposition: the reaction chamber is maintained at 1200-1400 ℃ for 2-3 h, a v1 valve is opened to start feeding raw material gas MTS (methyl trichlorosilane) into the furnace, the raw material gas enters in a dilution gas hydrogen bubbling mode, and deposition is carried out for 4-10 h at the temperature; raw material gas enters the furnace through a v1 valve by f1 and f2, the raw material gas is preheated to 300-500 ℃ in the area of a bottom heating system 6, the temperature rise time of the raw material gas entering a reaction chamber is shortened, the utilization rate of the raw material gas is improved, the heated raw material gas is divided into f3 which enters the reaction chamber from a bottom thermal field and f4 which enters the reaction chamber from a side part, 2N air inlet nozzles 10 are uniformly distributed at the bottom air inlet of f3 along the circumference, and 2N air inlet nozzles 10 are uniformly distributed at 3-5 layers at the side air inlet of f4 along the circumference in the longitudinal direction; the feed gas entering the reaction chamber from f1 and f3 is blocked by the baffle ring 11 to form a vortex to increase the residence time in the reaction chamber, the feed gas can be uniformly distributed in the deposition area of the workpiece 9 through the flow limiting holes 801 uniformly distributed on the carrying disc 8, and the feed gas concentration near the workpiece 9 stacked on the upper part can be increased through the gas inlet on the side part of f 4; the thermal field structure can ensure higher utilization rate of raw material gas and more uniform coating;

s105: cooling: after the reaction is finished, stopping introducing the raw material gas and starting cooling, and continuously introducing inert gas at the flow rate of 100-200L/min; after the temperature is reduced to 200 ℃, stopping introducing the inert gas, starting vacuumizing to be less than or equal to 100Pa, and refilling the inert gas to 100 Kpa;

s106: discharging: after the temperature is reduced to 50 ℃, the workpiece 9 can be taken out.

The working principle and the using process of the invention are as follows: by arranging the object carrying rotary mechanism 3, the object carrying rotary mechanism 3 rotates the workpiece 9, so that the raw material gas is more fully contacted with the workpiece 9, and the flow limiting hole 801 in the object carrying rotary mechanism 3 can effectively limit the flow velocity of the raw material gas, so that the residence time of the raw material gas in the reaction chamber is longer, and the utilization rate of the raw material gas is improved; through setting up air inlet nozzle 10, 2 bottoms of heat preservation along a plurality of air inlet nozzle 10 of circumference equipartition, 2 inside sides of heat preservation vertically divide 3 ~ 5 layers along a plurality of air inlet nozzle 10 of circumference equipartition, a plurality of air inlet nozzle 10 can fully spray the feed gas at work piece 9, increase near work piece 9 feed gas concentration that upper portion ramds and add, and the feed gas blocks through fender flow ring 11 and can form the vortex and increase the detention time at the reaction chamber, it can make the feed gas utilization ratio higher to go up the thermal field structure, the coating is more even.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.