Silicon carbide crystal deposition device and control method for inhibiting micropowder formation

Abstract

The present invention belongs to the technical field of semiconductor equipment, and specifically relates to a silicon carbide crystal deposition device and a control method for inhibiting the formation of micropowder. By setting a multi-ring rod body and corresponding material inlet pipelines and cold inlet pipelines, and timely adjusting the opening and closing and flow rates of different inlet pipelines according to the diameter of the rod body, since the high-temperature atmosphere is usually located in the area inside the gate-shaped rod body, cold gas is used to mix with the high-temperature atmosphere in the furnace to achieve the effect of cooling the atmosphere, thereby cooling the high-temperature atmosphere without affecting the crystal growth to reduce the reaction activity of the material, thereby achieving the purpose of inhibiting the formation of micropowder in the atmosphere, which is beneficial to improving the growth quality of silicon carbide crystals.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor equipment, and in particular relates to a silicon carbide crystal deposition device and a control method for inhibiting the formation of micropowder. Background Art

[0002] The bell-shaped reactor is used as a growth container for rod-shaped silicon carbide. In the reactor, the carrier is placed on the chassis in a gate-shaped or U-shaped structure, and each pair of rods consists of two vertical sections. The surface of the rods is always maintained at a specific reaction temperature of 900-1600℃. Feed ports are arranged at equal intervals between each pair of rods to feed cold materials into the reactor chamber. During the growth of silicon carbide rods, the surface of each rod continuously radiates heat outward, and the heat convection effect near the surface of the rod intensifies. The material gas is continuously heated by the rods, and the gas temperature in the rod surface area continues to rise, especially in the middle area of ​​each pair of rods, that is, the middle area of ​​the gate shape, which is heated by radiation and heat convection from the rods on both sides at the same time. The atmosphere temperature in this area is the highest.

[0003] Due to the high temperature of the atmosphere inside the gate-shaped carrier, the materials in the atmosphere are very likely to undergo homogeneous reactions in this area to form fine dust particles, which is the so-called atomization phenomenon. The silicon carbide particles formed by atomization are micron and submicron in size and are easily suspended in the atmosphere, causing the visibility of the furnace atmosphere to decrease, causing visual interference to the observation and control of the furnace phenomenon. At the same time, the dust formed by atomization is not easy to collect and will enter the subsequent tail gas recovery system with the reaction tail gas, which not only causes material waste, but also affects the stability of the tail gas recovery process at the back end, such as the blockage of pipeline valves and the stoppage of the compressor. In addition, since each pair of rods in the bell-shaped reactor is arranged at equal intervals and in a concentric circle array, in order to improve production capacity and equipment utilization, it is often arranged in 2, 3 or even 4 circles. The atomization phenomenon caused by this is constantly intensified, and it is difficult to regulate and suppress the production of silicon carbide micropowder through conventional methods such as material temperature, ratio, and flow.

[0004] It should be noted that this part of the present invention only provides background technology related to the present invention and does not necessarily constitute prior art or known technology. Summary of the invention

[0005] The purpose of the present invention is to provide a silicon carbide crystal deposition device and a control method for inhibiting the formation of micropowder, so as to overcome the problem that the existing silicon carbide deposition device is prone to produce micropowder that affects the quality of the rod.

[0006] In order to achieve the above-mentioned purpose, in a first aspect, a silicon carbide crystal deposition device provided by an embodiment of the present invention comprises: a cover body and a chassis; the chassis is sealed and matched with the bottom end of the cover body to form a deposition space; at least a plurality of first electrodes and a plurality of second electrodes are arranged on the chassis, the plurality of first electrodes form a first electrode ring, the plurality of second electrodes form a second electrode ring, the second electrode ring surrounds the first electrode ring, a first rod body is correspondingly arranged on the first electrode, and the top ends of two adjacent first rod bodies are connected by a first transverse rod body, and a second rod body is correspondingly arranged on the second electrode, and the top ends of two adjacent second rod bodies are connected by a second transverse rod body;

[0007] A plurality of first feed pipelines and a plurality of second feed pipelines are interspersed on the chassis, the plurality of first feed pipelines are distributed in the area between the first electrode ring and the second electrode ring, and the plurality of second feed pipelines are distributed on the periphery of the second electrode ring; the first feed pipeline and the second feed pipeline are respectively used to transport the reaction material to the deposition space; a first feed valve and a first feed metering component are provided on the first feed pipeline, and a second feed valve and a second feed metering component are provided on the second feed pipeline;

[0008] The chassis is also interspersed with a plurality of first cold inlet pipelines and a plurality of second cold inlet pipelines, wherein the first cold inlet pipeline is located at one end of the deposition space and faces the first transverse rod; the second cold inlet pipeline is located at one end of the deposition space and faces the second transverse rod; a first cold valve and a first cold metering component are provided on the first cold inlet pipeline, and a second cold valve and a second cold metering component are provided on the second cold inlet pipeline;

[0009] A crystal film thickness detection component is provided in the deposition space, and the crystal film thickness detection component is used to detect the diameters of the first rod body and the second rod body. The silicon carbide crystal deposition device also includes a control unit, and the control unit is electrically connected to the first feed valve, the first feed metering component, the second feed valve, the second feed metering component, the first cold valve, the first cold metering component, the second cold valve and the second cold metering component, respectively, and is used to control the first cold valve and the second cold valve to close or pass the reaction material when the control unit detects that the diameter of the first rod body and / or the second rod body is less than a first threshold value;

[0010] And, when the control unit detects that the diameter of the first rod and / or the second rod is greater than or equal to a first threshold and less than or equal to a second threshold, the first cold valve is controlled to open and cold gas is introduced, and the total flow of the first cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component;

[0011] Furthermore, when the control unit detects that the diameter of the first rod and / or the second rod is greater than a second threshold value, the first cold valve and the second cold valve are controlled to be opened simultaneously and to allow cold gas to pass through, and the total flow of the first cold metering component and the second cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component, and as the diameter of the rod increases, the total flow of the first cold metering component and the second cold metering component gradually decreases until it is closed.

[0012] Optionally, all the first cold-state valves are uniformly controlled by the control unit, or each of the first cold-state valves is individually controlled by the control unit; and / or all the second cold-state valves are uniformly controlled by the control unit, or each of the second cold-state valves is individually controlled by the control unit.

[0013] Optionally, all of the first cold state inlet pipelines are controlled by a single main pipeline, and gas volume distribution is performed in accordance with the nozzle aperture of the first cold state inlet pipeline; and / or, the second cold state inlet pipelines are controlled by a single main pipeline, and gas volume distribution is performed in accordance with the nozzle aperture of the second cold state inlet pipeline.

[0014] Optionally, the cold gas includes hydrogen or argon.

[0015] Optionally, the first feed pipeline and the second feed pipeline are used to provide a feed gas composition of a mixture of a carbon source, a silicon source and hydrogen to the deposition space.

[0016] Optionally, a first nozzle is provided at one end of the first cold inlet pipe facing the first transverse rod, and a second nozzle is provided at one end of the second cold inlet pipe facing the second transverse rod; the cross section of the first nozzle and / or the second nozzle is an elliptical cross section or a slender strip cross section.

[0017] Optionally, the orthographic projection of the long axis of the first nozzle on the chassis is orthogonal to the orthographic projection of the corresponding first transverse rod on the chassis; and / or, the orthographic projection of the long axis of the second nozzle on the chassis is orthogonal to the orthographic projection of the corresponding second transverse rod on the chassis.

[0018] Optionally, the height of the first cold inlet pipeline in the cover does not exceed 2 / 3 of the height of the first rod body, and is flush with the chassis at its lowest.

[0019] Optionally, the gas temperature of the first cold inlet pipeline and the second cold inlet pipeline does not exceed 300°C.

[0020] In a second aspect, an embodiment of the present invention further provides a method for controlling the formation of silicon carbide powder in the silicon carbide crystal deposition device according to the first aspect, comprising:

[0021] When the control unit detects that the diameter of the first rod and / or the second rod is smaller than a first threshold, the first cold valve and the second cold valve are controlled to be closed or to allow reaction materials to pass;

[0022] When the control unit detects that the diameter of the first rod and / or the second rod is greater than or equal to a first threshold value and less than or equal to a second threshold value, the first cold valve is controlled to be opened, and the total flow of the first cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component;

[0023] When the control unit detects that the diameter of the first rod and / or the second rod is greater than a second threshold, the first cold valve and the second cold valve are controlled to be opened at the same time, and the total flow of the first cold metering component and the second cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component, and as the diameter of the rod increases, the total flow of the first cold metering component and the second cold metering component gradually decreases until it is closed.

[0024] The embodiments of the present application have at least the following technical effects:

[0025] The silicon carbide crystal deposition device provided in the embodiment of the present invention is provided with multiple circles of rods and corresponding material inlet pipelines and cold inlet pipelines, and the opening and closing and flow rates of different inlet pipelines are timely adjusted according to the diameter of the rods. Since the high-temperature atmosphere is usually located in the area inside the gate-shaped rod, cold gas is used to mix with the high-temperature atmosphere in the furnace to achieve the effect of cooling the atmosphere, thereby cooling the high-temperature atmosphere without affecting the crystal growth to reduce the reaction activity of the material, thereby achieving the purpose of suppressing the formation of micropowder in the atmosphere, which is beneficial to improving the growth quality of silicon carbide crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of the overall structure of a silicon carbide crystal deposition device provided in an embodiment of the present invention;

[0028] Figure 2 A control module connection block diagram of a silicon carbide crystal deposition device provided in an embodiment of the present invention.

[0029] Reference numerals:

[0030] 100-cover; 110-deposition space; 200-chassis; 300-first electrode; 310-first rod; 320-first transverse rod; 400-second electrode; 410-second rod; 420-second transverse rod; 500-first feed pipeline; 510-first feed valve; 520-first feed metering component; 600-second feed pipeline; 610-second feed valve; 620-second feed metering component; 700-first cold inlet pipeline; 710-first nozzle; 720-first cold valve; 730-first cold metering component; 800-second cold inlet pipeline; 810-second nozzle; 820-second cold valve; 830-second cold metering component; 900-control unit; 1000-crystal film thickness detection component. DETAILED DESCRIPTION

[0031] The technical solution of the present application will be described clearly and completely in conjunction with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0032] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0033] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0034] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 should not be understood as a limitation on the present application.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0036] Combination Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a silicon carbide crystal deposition device, comprising: a cover body 100 and a bottom plate 200; the bottom plate 200 is sealed with the bottom end of the cover body 100 to form a sealed deposition space 110. At least a plurality of first electrodes 300 and a plurality of second electrodes 400 are arranged on the bottom plate 200, the plurality of first electrodes 300 form a first electrode 300 ring, the plurality of second electrodes 400 form a second electrode 400 ring, and the second electrode 400 ring surrounds the first electrode 300 ring, that is, the second electrode 400 is arranged on the periphery of the first electrode 300. The first electrode 300 is provided with a first rod 310, and the top ends of two adjacent first rods 310 are connected by a first transverse rod 320, and the position where the first transverse rod 320 is connected to the upper end of the first rod 310 is the corner area of ​​the first rod 310; the second electrode 400 is provided with a second rod 410, and the top ends of two adjacent second rods 410 are connected by a second transverse rod 420, and the position where the second transverse rod 420 is connected to the upper end of the second rod 410 is the corner area of ​​the second rod 410. It can be understood that in the embodiment of the present invention, only two circles of electrode rings are formed as an example for explanation, but it is not limited to only two circles of electrode rings, and can also include an arrangement of three or more circles of electrode rings, and the corresponding feed pipeline and cold inlet pipeline are expanded outward in sequence according to the distribution of the electrodes.

[0037] Specifically, a plurality of first feed pipelines 500 and a plurality of second feed pipelines 600 are interspersed on the chassis 200. The plurality of first feed pipelines 500 are distributed in the area between the first electrode 300 ring and the second electrode 400 ring, and the plurality of second feed pipelines 600 are distributed on the periphery of the second electrode 400 ring; the first feed pipeline 500 and the second feed pipeline 600 are respectively used to transport the reaction materials to the deposition space 110; the first feed pipeline 500 is provided with a first feed valve 510 and a first feed metering component 520, and the second feed pipeline 600 is provided with a second feed valve 610 and a second feed metering component 620. By controlling the flow of the feed valves on the respective feed pipelines, the deposition of the reaction materials on the corresponding rod body is achieved, thereby controlling the growth rate of the silicon carbide crystals on the rod body. In addition, an air outlet ( Figure 1 The gas outlet hole is used to discharge the excess gas after the reaction in the deposition space 110, so that the intake and exhaust form a circulation loop.

[0038] Optionally, the reaction materials introduced into the first feed pipeline 500 and the second feed pipeline 600 include a mixture of a silicon source, a carbon source and hydrogen.

[0039] For example, taking a bell-shaped reaction deposition device with 7 pairs of rods (3 pairs of first rods 310 and 4 pairs of second rods 410) as an example, the horizontal spacing between the two ends of the gate-shaped rod is 220-250 mm, and the rod diameter grows from the initial 8 mm to 180 mm. The rod gap of the same gate-shaped rod will be narrowed from 212-242 mm to 40-70 mm. During this process, the atmosphere temperature in the middle area of ​​the rod will gradually be heated to near the surface temperature of the rod, which is about 700-900°C. At this time, the surface temperature of the rod is 1000-1100°C, and the average temperature of the rest of the atmosphere is about 400-600°C. Therefore, nucleation reactions and the generation of micropowders in the atmosphere are very likely to occur in the middle area of ​​the rod.

[0040] Furthermore, a plurality of first cold inlet pipes 700 and a plurality of second cold inlet pipes 800 are interspersed on the chassis 200. The first cold inlet pipe 700 is located at one end of the deposition space 110 and faces the first transverse rod 320; the second cold inlet pipe 800 is located at one end of the deposition space 110 and faces the second transverse rod 420; the first cold inlet pipe 700 is provided with a first cold valve 720 and a first cold metering component 730, and the second cold inlet pipe 800 is provided with a second cold valve 820 and a second cold metering component 830. The cold gas is controlled by controlling the flow of the cold valves on each cold inlet pipe, thereby reducing the reaction activity of the material, so as to achieve the purpose of suppressing the formation of micropowder in the atmosphere.

[0041] Optionally, the cold gas entering the deposition space 110 from the first cold inlet pipeline 700 or the second cold inlet pipeline 800 includes hydrogen or argon, and may also be a carrier gas.

[0042] Optionally, the gas temperature of the first cold inlet pipeline 700 and the second cold inlet pipeline 800 does not exceed 300°C. Since the temperature of the low-temperature area of ​​the atmosphere is about 400-600°C, the temperature of the cold gas should be lower than this temperature, thereby achieving the effect of lowering the atmosphere temperature.

[0043] In order to better suppress the formation of fine powder, a crystal film thickness detection component 1000 is provided in the deposition space 110, and the crystal film thickness detection component 1000 is used to detect the diameters of the first rod 310 and the second rod 410, where the diameter refers to the total diameter after the silicon carbide crystal is deposited on the rod. The silicon carbide crystal deposition device also includes a control unit 900, which is electrically connected to the first feed valve 510, the first feed metering component 520, the second feed valve 610, the second feed metering component 620, the first cold valve 720 and the first cold metering component 730, respectively, and is used to control the first cold valve 720 and the second cold valve 820 to close or introduce the reaction material when the control unit 900 detects that the diameter of the first rod body 310 and / or the second rod body 410 is less than a first threshold value (for example: 50 mm). The introduction of the reaction material can cool the nozzle on the one hand to prevent the nozzle from being deposited after being heated by radiation and then clogging the nozzle hole. On the other hand, the reactant can be more evenly introduced into the deposition space 110. In terms of flow control, the amount of material introduced into the cold air inlet is only auxiliary feed and is not easy to be too large; wherein, the gas volume of the reaction material can be gradually reduced until the reaction material is cut off and the transition is made to replace it with a cold gas such as hydrogen or argon.

[0044] Furthermore, when the control unit 900 detects that the diameter of the first rod 310 and / or the second rod 410 is greater than or equal to the first threshold value (for example, 50 mm) and less than or equal to the second threshold value (for example, 80 mm), the first cold valve 720 is controlled to open and pass cold gas, and the flow rate of the first cold metering component 730 is controlled not to exceed 1 / 3 of the total flow rate of the first feed metering component 520 and the second feed metering component 620. For example, the flow rate of the first cold metering component 730 in the initial state is 0, and the maximum flow rate of the first cold metering component 730 does not exceed 1 / 3 of the total flow rate of the first feed metering component 520 and the second feed metering component 620. For example, the total intake flow rate of the first feed pipeline 500 and the second feed pipeline 600 is 500~3000Nm 3 / h, so as not to affect the normal growth of the rod, and also inhibit the formation of micro powder. During the reaction process, the diameter of the rod continues to increase, and the corresponding air intake volume gradually increases. The intake volume of cold gas and the intake volume of the material (main gas volume) maintain a constant ratio, and can also be adjusted according to the atomization situation in the furnace. The overall relationship is that the main gas volume is adjusted according to the rod growth process, and the larger the intake volume of cold gas, the weaker the atomization, which ultimately reduces the temperature of the high-temperature atmosphere and dilutes the material concentration in this area, thereby inhibiting the atomization phenomenon.

[0045] Furthermore, when the control unit 900 detects that the diameter of the first rod 310 and / or the second rod 410 is greater than a second threshold value (for example: 80 mm), the first cold valve 720 and the second cold valve 820 are controlled to be opened simultaneously and to allow cold gas to pass through, and the total flow of the first cold metering component 730 and the second cold metering component 830 is controlled not to exceed 1 / 3 of the total flow of the first feed metering component 520 and the second feed metering component 620, and as the diameter of the rod increases, the total flow of the first cold metering component 730 and the second cold metering component 830 gradually decreases until it is closed.

[0046] The silicon carbide crystal deposition device provided in the embodiment of the present invention is provided with multiple circles of rods and corresponding material inlet pipelines and cold inlet pipelines, and the opening and closing and flow rates of different inlet pipelines are timely adjusted according to the diameter of the rods. Since the high-temperature atmosphere is usually located in the area inside the gate-shaped rod, cold gas is used to mix with the high-temperature atmosphere in the furnace to achieve the effect of cooling the atmosphere, thereby cooling the high-temperature atmosphere without affecting the crystal growth to reduce the reaction activity of the material, thereby achieving the purpose of inhibiting the formation of micropowder in the atmosphere, thereby improving the growth quality of silicon carbide crystals.

[0047] Optionally, all first cold valves 720 are uniformly controlled by the control unit 900, which is beneficial to improve the control efficiency of cold gas; or each first cold valve 720 is controlled separately by the control unit 900, which is beneficial to adjust the rod diameter of different areas separately.

[0048] Optionally, all the second cold valves 820 are uniformly controlled by the control unit 900, which is beneficial to improve the control efficiency of the cold gas; or each second cold valve 820 is controlled separately by the control unit 900, which is beneficial to adjust the rod diameter of different areas separately.

[0049] Optionally, all first cold state inlet pipes 700 are controlled by a single main pipeline, and gas volume distribution is performed in accordance with the nozzle aperture of the first cold state inlet pipes 700. The air intake flow rate of the main pipeline is equal to the sum of the flow rates of all first cold state inlet pipes 700, and the flow rate of each first cold state inlet pipe 700 is adjusted according to the diameter of the corresponding first rod body 310.

[0050] Optionally, the second cold inlet pipeline 800 is controlled by a single main pipeline, and gas distribution is performed in conjunction with the nozzle aperture of the second cold inlet pipeline 800. The air intake flow rate of the main pipeline is equal to the sum of the flow rates of all second cold inlet pipelines 800, and the flow rate of each second cold inlet pipeline 800 is adjusted according to the diameter of the corresponding second rod body 410.

[0051] Optionally, the diameter of the second cold inlet pipe 800 is equal to the diameter of the first cold inlet pipe 700, the number of the first cold inlet pipes 700 is less than the number of the second cold inlet pipes 800, the number of the first cold inlet pipes 700 corresponds to the number of the first transverse rods 320, and the number of the second cold inlet pipes 800 corresponds to the number of the second transverse rods 420, thereby ensuring that the cold gas in different areas is distributed more evenly.

[0052] In some embodiments, a first nozzle 710 is disposed at one end of the first cold inlet pipe 700 facing the first transverse rod 320 , and the cross section of the first nozzle 710 is an elongated nozzle structure with an elliptical cross section or an elongated strip cross section.

[0053] Optionally, a second nozzle 810 is provided at one end of the second cold inlet pipe 800 facing the second transverse rod 420 , and the cross section of the second nozzle 810 is an elongated nozzle structure with an elliptical cross section or an elongated strip cross section.

[0054] Optionally, the aspect ratio of the first nozzle 710 and the second nozzle 810 is greater than or equal to 1.5:1 and less than or equal to 5:1, and the nozzles intersect the corresponding transverse rods perpendicularly and unequally, so as to minimize the temperature impact on the transverse rods while ensuring the gas flow rate. It is understandable that if the aspect ratio of the nozzle is too small, it will interfere with the surface temperature of the rod, reduce the temperature of the surface of the rod, and thus reduce the deposition rate; if the aspect ratio of the nozzle is too large, it will affect the ejection effect of the airflow, which is not conducive to the suppression of micro powder.

[0055] In this embodiment, a slender flat nozzle structure is adopted to prevent the cold airflow from blowing onto the surface of the rod, thereby reducing the temperature of the surface of the rod. If the cold airflow causes local cooling on the surface of the rod, the deposition rate in this area will be significantly slowed down, and pits or even bent rods can be seen with the naked eye.

[0056] In some embodiments, Figure 1 As shown, the orthographic projection of the long axis of the first nozzle 710 on the chassis 200 is orthogonal to the orthographic projection of the corresponding first transverse rod 320 on the chassis 200, and is arranged in coordination with the nozzle of the slender structure to reduce the cooling of the cold gas on the surface of the rod. The vertical intersection method also minimizes the impact of the cold airflow on the surface temperature of the rod.

[0057] In some embodiments, the orthographic projection of the long axis of the second nozzle 810 on the chassis 200 is arranged to be orthogonal to the orthographic projection of the corresponding second transverse rod 420 on the chassis 200 .

[0058] In some embodiments, continue to refer to Figure 1 , the height of the first cold inlet pipe 700 in the cover body 100 does not exceed 2 / 3 of the height of the first rod 310, and is at least flush with the chassis 200. Optionally, the height of the first cold inlet pipe 700 in the cover body 100 is 1 / 3 of the height of the first rod 310, that is, one end of the first cold inlet pipe 700 located in the cover body 100 is located at 1 / 3 of the height of the first rod 310. The first cold inlet pipe 700 is located below the high-temperature atmosphere area, which can achieve the purpose of targeted cooling. The nozzle height of the first cold inlet pipe 700 is too high, which is not conducive to the divergence of the cold intake air. At the same time, the cold air blows directly to the bottom of the first horizontal rod 320, which will cause cooling of the gate-shaped rod and inhibit its growth.

[0059] Based on the same inventive concept, the embodiment of the present invention further provides a control method for suppressing the formation of silicon carbide powder in a silicon carbide crystal deposition device (the specific structure of the silicon carbide crystal deposition device has been described in detail in the above embodiment and will not be repeated here). The control method comprises the following steps:

[0060] S100, when the control unit 900 detects that the diameter of the first rod 310 and / or the second rod 410 is smaller than the first threshold, the first cold valve 720 and the second cold valve 820 are controlled to be closed or to allow the reaction material to pass.

[0061] S200, when the control unit 900 detects that the diameter of the first rod 310 and / or the second rod 410 is greater than or equal to the first threshold and less than or equal to the second threshold, the first cold valve 720 is controlled to open, and the total flow of the first cold metering component 730 is controlled not to exceed 1 / 3 of the total flow of the first feed metering component 520 and the second feed metering component 620.

[0062] S300, when the control unit 900 detects that the diameter of the first rod body 310 and / or the second rod body 410 is greater than the second threshold value, the first cold valve 720 and the second cold valve 820 are controlled to be opened at the same time, and the total flow of the first cold metering component 730 and the second cold metering component 830 is controlled not to exceed 1 / 3 of the total flow of the first feed metering component 520 and the second feed metering component 620, and as the diameter of the rod body increases, the total flow of the first cold metering component 730 and the second cold metering component 830 gradually decreases until it is closed.

[0063] The embodiments of the present invention are described in detail below, which are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0064] Embodiment 1:

[0065] The present embodiment provides a control method for suppressing the formation of silicon carbide powder in a silicon carbide crystal deposition device. The silicon carbide crystal deposition device takes 7 pairs of rods as an example. The spacing between each pair of rods is 240 mm. The rods are arranged in two concentric circles. The inner circle has 3 pairs of first rods 310, and the outer circle has 4 pairs of second rods 410. The first cold inlet pipeline 700 of the inner circle has 3 air inlets (first nozzles 710) and adopts an elliptical structure. The major axis of the ellipse is 20 mm and the minor axis is 5 mm. The second cold inlet pipeline 800 of the outer circle has 4 air inlets (second nozzles 810) and adopts an elliptical structure. The major axis of the ellipse is 20 mm and the minor axis is 5 mm. The height of the first cold inlet pipeline 700 in the cover body 100 does not exceed 1 / 3 of the height of the first rod 310.

[0066] S100, when the rod diameter is 8-50 mm, the first cold inlet pipeline 700 and the second cold inlet pipeline 800 are closed, and the total flow rate of silicon source, carbon source and hydrogen in the main air inlet (first feed pipeline 500 and second feed pipeline 600) is 0-1000 Nm 3 / h, C:Si:H2=1:1:20.

[0067] S200, when the rod diameter is greater than 50 mm, open the first cold inlet pipeline 700, close the second cold inlet pipeline 800, and introduce hydrogen into the first cold inlet pipeline 700 at a flow rate of 0-600 Nm 3 / h, the total flow rate of silicon source, carbon source and hydrogen at the main air inlet is 1000-2000Nm 3 / h, C:Si:H2=1:1:20, until the crystal growth is completed.

[0068] S300, when the rod diameter is greater than 80 mm, open the first cold inlet pipeline 700 and the second cold inlet pipeline 800, and introduce hydrogen into the cold inlet with a flow rate of 600-1000 Nm 3 / h, the total flow rate of silicon source, carbon source and hydrogen at the main air inlet is 2000-3000Nm 3 / h, C:Si:H2=1:1:20.

[0069] Example 2

[0070] This embodiment provides a control method for inhibiting the formation of silicon carbide powder in a silicon carbide crystal deposition device. In step S200, the flow rate of the first cold inlet pipeline 700 is 0-100 Nm 3 / h.

[0071] Example 3

[0072] This embodiment provides a control method for inhibiting the formation of silicon carbide powder in a silicon carbide crystal deposition device. In step S300, the total flow rate of the first cold inlet pipeline 700 and the second cold inlet pipeline 800 is 100-300 Nm 3 / h.

[0073] Embodiment 4:

[0074] This embodiment provides a control method for inhibiting the formation of silicon carbide micropowder in a silicon carbide crystal deposition device. Different from Example 1, in the silicon carbide crystal deposition device adopted therein, the height of the first nozzle 710 corresponding to the first cold inlet pipeline 700 is 1 / 2 of the total height of the first rod body 310, and the height of the second nozzle 810 corresponding to the second cold inlet pipeline 800 is 1 / 2 of the total height of the second rod body 410.

[0075] Embodiment 5:

[0076] This embodiment provides a control method for suppressing the formation of silicon carbide micropowder in a silicon carbide crystal deposition device. The difference from Example 1 is that in the silicon carbide crystal deposition device adopted therein, the length-to-width ratio of the first nozzle 710 corresponding to the first cold inlet pipeline 700 is 2:1, and the length-to-width ratio of the second nozzle 810 corresponding to the second cold inlet pipeline 800 is 2:1.

[0077] Comparative Example 1:

[0078] The control method for suppressing the formation of silicon carbide powder in this comparative example adopts a conventional silicon carbide deposition device, in which the first cold inlet pipeline 700 and the second cold inlet pipeline 800 are not arranged.

[0079] Comparative Example 2:

[0080] This comparative example provides a control method for inhibiting the formation of silicon carbide powder. Although the silicon carbide crystal deposition device is provided with a first cold inlet pipeline 700 and a second cold inlet pipeline 800, the flow rates of the first cold inlet pipeline 700 and the second cold inlet pipeline 800 are constant at 50 Nm 3 / h, and has no linkage relationship with the diameter of the corresponding rod.

[0081] Comparative Example 3:

[0082] The present comparative example provides a control method for inhibiting the formation of silicon carbide micropowder. Although the silicon carbide crystal deposition device is provided with a first cold inlet pipeline 700 and a second cold inlet pipeline 800, and the flow rates of the first cold inlet pipeline 700 and the second cold inlet pipeline 800 are adjusted according to the diameter of the corresponding rod body, the total flow rate of the first cold inlet pipeline 700 and the second cold inlet pipeline 800 is equal to 1 / 2 of the total flow rate of the first feed pipeline 500 and the second feed pipeline 600. The cold airflow is too large, which significantly affects the temperature inside the rod body, thereby reducing the surface temperature and growth rate of the rod body, resulting in slow growth on the inside and fast growth on the outside, resulting in a shift in the center of gravity and thus causing the rod to fall. At the same time, due to interference with the material circulation path of the main gas path, the effective contact and reaction efficiency between the material and the rod surface are reduced, thereby reducing the material conversion rate.

[0083] Table 1 is the powder generation ratio in different embodiments and comparative examples calculated by collecting and weighing the fine powder settled on the bottom plate in the corresponding reaction furnace in different embodiments and comparative examples, and adding the weight to the rod weight.

[0084] Table 1 Comparison results of the proportion of micropowder corresponding to different embodiments and comparative examples

[0085]

[0086] Compared with Example 2, the cold gas volume in step S200 of Example 1 is greater than that of Example 2, which can suppress the generation of micropowder earlier and reduce the overall generation of micropowder. Compared with Example 3, the cold gas volume in step S300 of Example 1 is larger, which can effectively suppress the generation of powder in the middle and late stages of growth and significantly reduce the proportion of micropowder. Compared with Example 4, the height of the cold air intake nozzle of Example 1 does not exceed one-third of the height of the rod body, while the height of the cold air intake nozzle of Example 4 is one-half. The cold air intake of Example 4 can effectively suppress the generation of powder in the middle and upper area of ​​the inner side of the rod body, but cannot effectively suppress the generation of powder in the middle and lower area of ​​the inner side of the rod body. The aspect ratio of the cold air intake nozzle of Example 5 is 2:1. After the diameter of the rod increases in the middle and late stages of the growth of the rod body, the distance between the inner side of the rod body and the cold air intake nozzle is shortened, and the inner surface temperature of the rod body is aggravated by the cold air intake, resulting in an increase in the deviation of the rod body diameter.

[0087] The difference between Comparative Example 1 and Example 1 is that cold air intake is not set, so the growth inside the rod body is not affected by cold air intake, and the deviation of the rod body diameter can be reduced, but the micro-powder effect produced by the high-temperature atmosphere inside the rod body is the most significant. Although cold air intake is set in Comparative Example 2, the cold air intake volume remains constant and the flow rate is small, which has a great impact on the growth inside the rod body in the early stage of growth, resulting in a deviation in the rod body diameter and maintaining this deviation in the middle and late stages. In the middle and late stages of growth, the cold air intake volume is too small to effectively inhibit the generation of powder, resulting in poor effect in inhibiting the generation of powder. The cold air intake volume of Comparative Example 3 is significantly larger than that of Example 1, and it can still effectively inhibit the generation of powder in the high-temperature atmosphere inside the rod body. However, due to the excessive gas volume, the stable flow of the airflow on the surface of the rod body is significantly affected, and the temperature uniformity and growth rate uniformity inside and outside the rod body are reduced, resulting in a large deviation in the rod body diameter. At the same time, the large airflow leads to insufficient reaction in the furnace, which will reduce the conversion rate of the material.

[0088] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances. In the description of this specification, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A silicon carbide crystal deposition device, characterized in that: include: Cover and chassis; The bottom plate is sealed and matched with the bottom end of the cover body to form a deposition space; At least a plurality of first electrodes and a plurality of second electrodes are arranged on the chassis, the plurality of first electrodes form a first electrode ring, the plurality of second electrodes form a second electrode ring, the second electrode ring surrounds the first electrode ring, a first rod is correspondingly arranged on the first electrode, the top ends of two adjacent first rods are connected by a first transverse rod, and a second rod is correspondingly arranged on the second electrode, the top ends of two adjacent second rods are connected by a second transverse rod; A plurality of first feed pipelines and a plurality of second feed pipelines are interspersed on the chassis, the plurality of first feed pipelines are distributed in the area between the first electrode ring and the second electrode ring, and the plurality of second feed pipelines are distributed on the periphery of the second electrode ring; the first feed pipeline and the second feed pipeline are respectively used to transport the reaction material to the deposition space; a first feed valve and a first feed metering component are provided on the first feed pipeline, and a second feed valve and a second feed metering component are provided on the second feed pipeline; The chassis is also interspersed with a plurality of first cold inlet pipelines and a plurality of second cold inlet pipelines, wherein the first cold inlet pipeline is located at one end of the deposition space and faces the first transverse rod; The second cold inlet pipeline is located at one end of the deposition space and faces the second transverse rod; a first cold valve and a first cold metering component are provided on the first cold inlet pipeline, and a second cold valve and a second cold metering component are provided on the second cold inlet pipeline; A crystal film thickness detection component is provided in the deposition space, and the crystal film thickness detection component is used to detect the diameters of the first rod body and the second rod body. The silicon carbide crystal deposition device also includes a control unit, and the control unit is electrically connected to the first feed valve, the first feed metering component, the second feed valve, the second feed metering component, the first cold valve, the first cold metering component, the second cold valve and the second cold metering component, respectively, and is used to control the first cold valve and the second cold valve to close or pass the reaction material when the control unit detects that the diameter of the first rod body and / or the second rod body is less than a first threshold value; And, when the control unit detects that the diameter of the first rod and / or the second rod is greater than or equal to a first threshold and less than or equal to a second threshold, the first cold valve is controlled to open and cold gas is introduced, and the total flow of the first cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component; And, when the control unit detects that the diameter of the first rod and / or the second rod is greater than a second threshold value, the first cold valve and the second cold valve are controlled to be opened simultaneously and to pass cold gas, and the total flow of the first cold metering component and the second cold metering component is controlled not to exceed 1 / 3 of the total flow of the first feed metering component and the second feed metering component, and as the diameter of the rod increases, the total flow of the first cold metering component and the second cold metering component gradually decreases until they are closed; The height of the first cold inlet pipeline in the cover does not exceed 1 / 3 of the height of the first rod body, and is flush with the bottom plate at the lowest point; A first nozzle is disposed at one end of the first cold inlet pipe facing the first transverse rod, and a second nozzle is disposed at one end of the second cold inlet pipe facing the second transverse rod; cross sections of the first nozzle and the second nozzle are elongated strip cross sections, and a length-to-width ratio of the first nozzle and the second nozzle is greater than or equal to 1.5:1 and less than or equal to 5:1; The orthographic projection of the long axis of the first nozzle on the chassis is orthogonal to the orthographic projection of the corresponding first transverse rod on the chassis; the orthographic projection of the long axis of the second nozzle on the chassis is orthogonal to the orthographic projection of the corresponding second transverse rod on the chassis.

2. The silicon carbide crystal deposition device according to claim 1, characterized in that: All the first cold-state valves are uniformly controlled by the control unit, or each of the first cold-state valves is individually controlled by the control unit; And / or, all the second cold-state valves are uniformly controlled by the control unit, or each of the second cold-state valves is individually controlled by the control unit.

3. The silicon carbide crystal deposition device according to claim 1, characterized in that: All the first cold state inlet pipelines are controlled by a single main pipeline, and the gas volume is distributed in accordance with the nozzle aperture of the first cold state inlet pipeline; And / or, the second cold inlet pipeline is controlled by a single main pipeline, and the gas volume is distributed in accordance with the nozzle aperture of the second cold inlet pipeline.

4. The silicon carbide crystal deposition device according to claim 1, characterized in that: The cold gas includes hydrogen or argon.

5. The silicon carbide crystal deposition device according to claim 1, characterized in that: The first feed pipeline and the second feed pipeline are used to provide a mixture of a feed gas composed of a carbon source, a silicon source and hydrogen to the deposition space.

6. The silicon carbide crystal deposition device according to claim 1, characterized in that: The gas temperature of the first cold state inlet pipeline and the second cold state inlet pipeline does not exceed 300°C.

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