CN115092931B - Control method and control system for producing polycrystalline silicon - Google Patents

Control method and control system for producing polycrystalline silicon Download PDF

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Publication number
CN115092931B
CN115092931B CN202210759614.2A CN202210759614A CN115092931B CN 115092931 B CN115092931 B CN 115092931B CN 202210759614 A CN202210759614 A CN 202210759614A CN 115092931 B CN115092931 B CN 115092931B
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pipeline
dichlorosilane
regulating valve
trichlorosilane raw
reduction furnace
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CN115092931A (en
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吕海花
李大伟
李伟
邵雅雅
王旭
张福川
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Xinjiang Xinte Crystal Silicon High Tech Co ltd
Xinte Energy Co Ltd
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Xinjiang Xinte Crystal Silicon High Tech Co ltd
Xinte Energy Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00Silicon; Compounds thereof
    • C01B33/02Silicon
    • C01B33/021Preparation
    • C01B33/027Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
    • C01B33/035Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00Programme-control systems
    • G05B19/02Programme-control systems electric
    • G05B19/418Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
    • G05B19/41875Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by quality surveillance of production

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  • Engineering & Computer Science (AREA)
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  • Quality & Reliability (AREA)
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  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Silicon Compounds (AREA)

Abstract

The application discloses a novel control method and a control system for producing polysilicon, wherein the method comprises the following steps: introducing trichlorosilane raw materials and hydrogen into a reducing furnace for hydrogen reduction reaction to generate polycrystalline silicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride, and the trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride are introduced into the reducing furnace in different preset growth stages of a silicon rod, so that the deposition speed and atomization phenomenon of the polycrystalline silicon on the silicon rod are controlled. According to the application, through researching the operation characteristics of the silicon rod in the reduction furnace in different growth stages, trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride with different preset contents are introduced in different growth stages to perform hydrogen reduction reaction with hydrogen, so that the purpose of whole-course high-speed production of the reduction furnace is achieved, the deposition speed of polysilicon is improved, the silicon rod is prevented from growing more fragile, and the silicon rod is easy to fall into the furnace; but also can ensure the appearance quality of the polysilicon and reduce the atomization phenomenon.

Description

Control method and control system for producing polycrystalline silicon
Technical Field
The application belongs to the technical field of polysilicon production, and particularly relates to a control method and a control system for producing polysilicon.
Background
Currently, the mainstream polysilicon production technology at home and abroad is an improved siemens method. In a reduction reaction unit of trichlorosilane, the vaporized and preheated trichlorosilane and hydrogen are mixed according to a certain proportion and then enter a reduction furnace, and chemical vapor deposition reaction is carried out on an electrified high-temperature silicon core at 1050-1100 ℃ to obtain high-purity polysilicon.
The traditional process control mode is that trichlorosilane refined materials used in the whole growth process from feeding to stopping of a reduction furnace generally contain dichlorosilane accounting for about 2% -5%, silicon rods in the reduction furnace are fragile in growth process, the furnace is easy to fall down, atomization occurs, and the apparent mass of the silicon rods is abnormal.
Disclosure of Invention
The application aims to solve the technical problems in the prior art, and provides a control method and a control system for producing polycrystalline silicon, which can improve the deposition rate of the polycrystalline silicon and ensure the appearance quality of the polycrystalline silicon.
The technical scheme adopted for solving the technical problem of the application is to provide a control method for producing polysilicon, which comprises the following steps:
introducing trichlorosilane raw materials and hydrogen into a reducing furnace for hydrogen reduction reaction to generate polycrystalline silicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride, and the trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride are introduced into the reducing furnace in different preset growth stages of a silicon rod, so that the deposition speed and atomization phenomenon of the polycrystalline silicon on the silicon rod are controlled.
The deposition speed of the polysilicon is improved by dichlorosilane, so that the silicon rod is prevented from growing more brittle and is easy to be poured into a furnace; the appearance quality of the polysilicon is guaranteed through the silicon tetrachloride, and the atomization phenomenon is reduced.
Preferably, the content of dichlorosilane in the trichlorosilane raw material is 2-10 mas% in different preset growth stages of the silicon rod.
Preferably, the content of silicon tetrachloride in the trichlorosilane raw material is 1-5 mas% in different preset growth stages of the silicon rod.
Preferably, the different preset growth phases of the silicon rod comprise: the first growth stage is within the first 30 hours, the second growth stage is 31-60 hours, the third growth stage is 61-100 hours, and the content of dichlorosilane in the trichlorosilane raw material is sequentially reduced in the three growth stages from the first growth stage to the third growth stage.
Preferably, in the different preset growth stages of the silicon rod, introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into a reduction furnace, wherein the method specifically comprises the following steps of:
the first growth stage is that during the first 30 hours, the content of dichlorosilane in the trichlorosilane raw material is 8-10 mas;
the second growth stage is 31-60 h, the content of dichlorosilane in the raw material of trichlorosilane is 4-6mas, and the content of silicon tetrachloride is 3.1-5 mas;
the third growth stage is 61-100 h, the content of dichlorosilane in the introduced trichlorosilane raw material is 2-3mas percent, and the content of silicon tetrachloride is 1-3mas percent.
The silicon tetrachloride is used for inhibiting the atomization effect in the middle-stage and later-stage reduction furnace so as to ensure the normal appearance quality of the reduction furnace.
Preferably, the temperature of the hydrogen reduction reaction is 1050 to 1100 ℃.
Preferably, the volume ratio of the trichlorosilane raw material containing dichlorosilane and hydrogen gas which are introduced into the reducing furnace is 1: (2-5).
Preferably, the trichlorosilane raw material, the pure trichlorosilane raw material and the pure silicon tetrachloride raw material which contain high-component dichlorosilane are respectively introduced into the reduction furnace, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8-10mas, and the dichlorosilane and the silicon tetrachloride in the trichlorosilane raw material introduced into the reduction furnace are regulated to be different preset contents.
The application also provides a control system used for the control method, which comprises the following steps:
the reduction furnace is used for introducing trichlorosilane raw materials and hydrogen into the reduction furnace for hydrogen reduction reaction to generate polysilicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride;
the adjusting device is connected with the reducing furnace and is used for introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into the reducing furnace in different preset growth stages of the silicon rod, so as to control the deposition speed and atomization phenomenon of the polysilicon on the silicon rod;
and the atomization detection device is connected with the tail gas emission pipeline of the reduction furnace, is used for detecting the atomization phenomenon in the reduction furnace and is sent to the adjusting device.
Preferably, the adjusting device comprises:
the first pipeline is connected with the reduction furnace, a first regulating valve is arranged on the first pipeline, and the first pipeline is used for introducing a trichlorosilane raw material containing high-component dichlorosilane into the reduction furnace, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8-10 mas;
the second pipeline is connected with the reduction furnace, a second regulating valve is arranged on the second pipeline, and the second pipeline is used for introducing pure trichlorosilane raw materials into the reduction furnace;
the third pipeline is connected with the reduction furnace, a third regulating valve is arranged on the third pipeline, and the third pipeline is used for introducing pure silicon tetrachloride raw materials into the reduction furnace;
the control unit is respectively connected with the first regulating valve, the second regulating valve and the third regulating valve, and the control unit adjusts the opening degrees of the first regulating valve, the second regulating valve and the third regulating valve to different growth stages of the silicon rod, so that dichlorosilane and silicon tetrachloride in the trichlorosilane raw material entering the reducing furnace are different in preset content.
Preferably, the adjusting device further comprises:
the fourth pipeline is connected with the reduction furnace, a fourth regulating valve is arranged on the fourth pipeline, the fourth pipeline is respectively connected with the first pipeline, the second pipeline and the third pipeline, and gas in the first pipeline, the second pipeline and the third pipeline flows into the reduction furnace through the fourth pipeline;
the fifth pipeline is connected with the reduction furnace, a fifth regulating valve is arranged on the fifth pipeline, the fifth pipeline is used for introducing hydrogen into the reduction furnace, the control unit is respectively connected with the fourth regulating valve and the fifth regulating valve, and the control unit regulates the volume ratio of trichlorosilane raw materials containing dichlorosilane and hydrogen which are introduced into the reduction furnace to be a preset volume ratio by respectively controlling the opening degrees of the fourth regulating valve and the fifth regulating valve.
Compared with the prior art, the control method and the control system for producing the polysilicon have the beneficial effects that:
according to the application, through researching the operation characteristics of the silicon rod in the reducing furnace in different growth stages, trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride with different preset contents are introduced in different growth stages to perform hydrogen reduction reaction with hydrogen, so that the purpose of whole-course high-speed production of the reducing furnace is achieved, the deposition speed of polysilicon can be improved, the silicon rod is prevented from growing more fragile, and the silicon rod is easy to fall into the furnace; but also can ensure the appearance quality of the polysilicon and reduce the atomization phenomenon.
Drawings
Fig. 1 is a schematic configuration diagram of a control system in embodiment 2 of the present application.
In the figure: 1-a first regulating valve; 2-a second regulating valve; 3-a third regulating valve; 4-a fourth regulating valve; 5-a fifth regulating valve; 6-an atomization detection device; 7-a first line; 8-a second line; 9-a third line; 10-fourth pipeline; 11-fifth line; 12-reducing furnace.
Detailed Description
The present application will be described in further detail below with reference to the drawings and detailed description for the purpose of better understanding of the technical solution of the present application to those skilled in the art.
Embodiments of the present patent are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present patent and are not to be construed as limiting the present patent.
Example 1
The embodiment provides a control method for producing polysilicon, comprising the following steps:
introducing trichlorosilane raw materials and hydrogen into a reducing furnace for hydrogen reduction reaction to generate polycrystalline silicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride, and the trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride are introduced into the reducing furnace in different preset growth stages of a silicon rod, so that the deposition speed and atomization phenomenon of the polycrystalline silicon on the silicon rod are controlled.
The embodiment also provides a control system used in the control method, which comprises:
the reduction furnace is used for introducing trichlorosilane raw materials and hydrogen into the reduction furnace for hydrogen reduction reaction to generate polysilicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride;
the adjusting device is connected with the reducing furnace and is used for introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into the reducing furnace in different preset growth stages of the silicon rod, so as to control the deposition speed and atomization phenomenon of the polysilicon on the silicon rod;
and the atomization detection device is connected with the tail gas emission pipeline of the reduction furnace, is used for detecting the atomization phenomenon in the reduction furnace and is sent to the adjusting device.
According to the embodiment, through researching the operation characteristics of the silicon rod in the reducing furnace in different growth stages, the trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride with different preset contents are introduced in different growth stages to perform hydrogen reduction reaction with hydrogen, so that the aim of whole-course high-speed production of the reducing furnace is fulfilled, the deposition speed of polycrystalline silicon can be improved, the silicon rod is prevented from growing more fragile, and the silicon rod is easy to fall into the furnace; but also can ensure the appearance quality of the polysilicon and reduce the atomization phenomenon.
Example 2
The embodiment provides a control method for producing polysilicon, comprising the following steps:
introducing trichlorosilane raw materials containing Dichlorosilane (DCS) and Silicon Tetrachloride (STC) and hydrogen into the reduction furnace 12 for hydrogen reduction reaction to generate polysilicon, wherein the Trichlorosilane (TCS) raw materials with different preset contents of dichlorosilane and silicon tetrachloride are introduced into the reduction furnace 12 at different preset growth stages of the silicon rod, and the polysilicon deposition speed and atomization phenomenon on the silicon rod are controlled.
The deposition speed of the polysilicon is improved by dichlorosilane, so that the silicon rod is prevented from growing more brittle and is easy to be poured into a furnace; the appearance quality of the polysilicon is guaranteed through the silicon tetrachloride, and the atomization phenomenon is reduced.
Preferably, the content of dichlorosilane in the trichlorosilane raw material is 2-10 mas% in different preset growth stages of the silicon rod.
Preferably, the content of silicon tetrachloride in the trichlorosilane raw material is 1-5 mas% in different preset growth stages of the silicon rod.
Preferably, the different preset growth phases of the silicon rod comprise: the first growth stage is within the first 30 hours, the second growth stage is 31-60 hours, the third growth stage is 61-100 hours, and the content of dichlorosilane in the trichlorosilane raw material is sequentially reduced in the three growth stages from the first growth stage to the third growth stage.
Preferably, in the different preset growth stages of the silicon rod, introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into a reduction furnace, wherein the method specifically comprises the following steps of:
the first growth stage is that during the first 30 hours, the content of dichlorosilane in the trichlorosilane raw material is 8-10 mas;
the second growth stage is 31-60 h, the content of dichlorosilane in the raw material of trichlorosilane is 4-6mas, and the content of silicon tetrachloride is 3.1-5 mas;
the third growth stage is 61-100 h, the content of dichlorosilane in the introduced trichlorosilane raw material is 2-3mas percent, and the content of silicon tetrachloride is 1-3mas percent.
The hydrogen reduction reaction in the reduction furnace is H 2 +SiHCl 3 After the reaction has been performed for a period of time, the self-decomposition reaction of trichlorosilane generates more and more silicon, which causes atomization phenomenon, and the self-decomposition reaction of trichlorosilane is 2SiHCl 3 =2Si+2HCl+SiCl 4 By introducing silicon tetrachloride, the self-decomposition reaction of trichlorosilane can be inhibited, and thus the atomization phenomenon is inhibited.
Preferably, the temperature of the hydrogen reduction reaction is 1050 to 1100 ℃.
Specifically, the temperature of the hydrogen reduction reaction in this example was 1070 ℃.
Preferably, the volume ratio of the trichlorosilane raw material and the hydrogen gas introduced into the reduction furnace 12 is 1: (2-5). The hydrogen gas introduced into the reduction furnace 12 is high purity hydrogen gas.
Specifically, in this embodiment, the volume ratio of trichlorosilane raw material and hydrogen gas introduced into the reduction furnace 12 is 1:4.
preferably, the trichlorosilane raw material, the pure trichlorosilane raw material and the pure silicon tetrachloride raw material containing high-component dichlorosilane are respectively introduced into the reduction furnace 12, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8-10mas, and the dichlorosilane and the silicon tetrachloride in the trichlorosilane raw material introduced into the reduction furnace 12 are regulated to different preset contents.
Specifically, the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane in this example was 9mas%.
As shown in fig. 1, this embodiment further provides a control system for the control method, including:
a reducing furnace 12, which is used for introducing trichlorosilane raw material and hydrogen into the reducing furnace 12 to perform hydrogen reduction reaction to generate polysilicon, wherein the trichlorosilane raw material is trichlorosilane raw material containing dichlorosilane and silicon tetrachloride;
the adjusting device is connected with the reducing furnace 12 and is used for introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into the reducing furnace 12 in different preset growth stages of the silicon rod, so as to control the deposition speed and atomization phenomenon of the polysilicon on the silicon rod;
and the atomization detection device 6 is connected with the tail gas discharge pipeline of the reduction furnace 12, and the atomization detection device 6 is used for detecting the atomization phenomenon in the reduction furnace 12 and sending the atomization phenomenon to the adjusting device.
Preferably, the adjusting device comprises:
the first pipeline 7 is connected with the reduction furnace 12, the first pipeline 7 is provided with a first regulating valve 1, and the first pipeline 7 is used for introducing a trichlorosilane raw material containing high-component dichlorosilane into the reduction furnace 12, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8-10 mas; the Dichlorosilane (DCS) component of the feed in the first line 7 is a fixed value with a fluctuation range of not more than 0.5mas%. Specifically, the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane in this example was 9mas%.
The second pipeline 8 is connected with the reduction furnace 12, a second regulating valve 2 is arranged on the second pipeline 8, and the second pipeline 8 is used for introducing pure trichlorosilane raw materials into the reduction furnace 12; the DCS component in the second line 8 was 0%.
The third pipeline 9 is connected with the reduction furnace 12, a third regulating valve 3 is arranged on the third pipeline 9, and the third pipeline 9 is used for introducing pure silicon tetrachloride raw material into the reduction furnace 12;
the control unit is respectively connected with the first regulating valve 1, the second regulating valve 2 and the third regulating valve 3, and adjusts the opening degrees of the first regulating valve 1, the second regulating valve 2 and the third regulating valve 3 to different growth stages of the silicon rod by respectively adjusting the contents of dichlorosilane and silicon tetrachloride in the trichlorosilane raw material entering the reducing furnace 12.
Preferably, the adjusting device further comprises:
a fourth pipeline 10 connected with the reduction furnace 12, wherein a fourth regulating valve 4 is arranged on the fourth pipeline 10, the fourth pipeline 10 is respectively connected with the first pipeline 7, the second pipeline 8 and the third pipeline 9, and the gas in the first pipeline 7, the second pipeline 8 and the third pipeline 9 flows into the reduction furnace 12 through the fourth pipeline 10; within the fourth line 10 is a mix.
The fifth pipeline 11 is connected with the reduction furnace 12, a fifth regulating valve 5 is arranged on the fifth pipeline 11, the fifth pipeline 11 is used for introducing hydrogen into the reduction furnace 12, the control unit is respectively connected with the fourth regulating valve 4 and the fifth regulating valve 5, and the control unit regulates the volume ratio of trichlorosilane raw materials and hydrogen which are introduced into the reduction furnace 12 to be a preset volume ratio by respectively controlling the opening degrees of the fourth regulating valve 4 and the fifth regulating valve 5.
In a growth period of the reduction furnace 12, raw materials in 0-30 h, 31-60 h and 61-100 h are distributed in a stable control mode, refined materials with different DCS (distributed control system) accounts for each stage, and the valve opening of a first regulating valve 1 and a valve opening of a second regulating valve 2 respectively corresponding to a first pipeline 7 where a trichlorosilane raw material containing high-component DCS is located and a second pipeline 8 where a refined material containing 0mas%DCS is located are determined through background calculation, so that the proportion of DCS content in the mixed material is within the control requirement range of different stages: by controlling the first regulating valve 1 and the second regulating valve 2 by a control unit.
When the reduction furnace 12 is started for feeding, the first regulating valve 1, the second regulating valve 2 and the third regulating valve 3 are opened on site, and the control unit automatically calculates the opening of the first regulating valve 1, the opening of the second regulating valve 2 and the opening of the third regulating valve 3 according to the proportion of the content of the dichlorosilane and the proportion of the content of the silicon tetrachloride which are led in the background, so that the content of the dichlorosilane and the content of the silicon tetrachloride in the raw materials entering the reduction furnace 12 meet the requirement of the growth stage of the silicon rod. The fourth regulating valve 4 and the fifth regulating valve 5 in front of the reduction furnace 12 automatically raise the current, trichlorosilane (TCS) and hydrogen flow according to the feeding table.
Because the first growth stage of the silicon rod is the first 30 hours in the operation early stage of the reduction furnace 12, the silicon core is thinner, the temperature in the furnace is not easy to gather, the control unit automatically opens the first regulating valve 1 and the second regulating valve 2, calculates the opening calculation flow of the first regulating valve 1 and the second regulating valve 2 according to the TCS flow monitored in real time, controls the DCS content in the raw materials to be controlled at 8-10mas,
after the operation is carried out for 30 hours, the diameter of the silicon rods is increased, the heat radiation performance among the silicon rods is increased, the heat is easy to accumulate, the deposition speed is also obviously improved, and the atomization is easy to occur in the furnace, at the moment, the DCS component in the raw materials is gradually controlled down, the DCS content in the raw materials is downwards regulated to 4-6mas in the period of 31-60 hours, the stage is the atomization peak period, the control unit opens the third regulating valve 3, and the flow of silicon tetrachloride is controlled in stages according to the proportion set by the background, at the moment, silicon tetrachloride is dosed according to the proportion of 3.1-5 mas, so that the atomization effect in the furnace is inhibited;
during the operation of the reduction furnace 12, the atomization detecting device 6 presents a slow and steady rise, and the fluctuation range is in a controllable range.
The DCS content in the raw material is regulated to 2-3mas in 61-100 h, when the measured value of the atomization detection device 6 rises by 5-10g/m within 1 minute 3 Or the fluctuation range exceeds 10-20g/m 3 The control unit controls the opening of the third regulating valve 3, so that the DCS proportion in the stage is regulated and controlled according to the mixture with the lower control of 0.5-1mas percent, the hydrogen flow is synchronously lifted, the lifting amplitude of each time is more than or equal to 2kg/h, and silicon tetrachloride is thrown according to the proportion of 1-3mas percent until the reducing furnace 12 is stopped.
The atomization detection device 6 monitors the measured value in real time, measures the deposition amount of the silicon powder in the pipeline, and judges the atomization degree by detecting the yield of the granularity of the silicon powder. In different stages, if a steep rising trend occurs, the valve opening of the first regulating valve 1 and the valve opening of the second regulating valve 2 respectively corresponding to the first pipeline 7 and the second pipeline 8 are regulated, so that the ratio of DCS content in the mixture is reduced, the hydrogen flow is simultaneously increased, and the atomization is pre-controlled in advance.
The inventor of the present application found that the content of dichlorosilane in the raw material in the reducing furnace 12 has a certain influence on the growth of polysilicon, and when the content of dichlorosilane is too small, the deposition rate of silicon rods is slow, the silicon rods grow more fragile, and the furnace is easy to be turned; when the content of dichlorosilane is excessive, the content of the reducing furnace 12 is easy to atomize in the later growth period, so that the apparent mass of the silicon rod is abnormal. Therefore, for the traditional process control mode, a method for improving the deposition speed of the polysilicon and ensuring the appearance quality of the polysilicon is required to be searched.
The control method and the control system for producing the polysilicon aim at the problem of low deposition speed in the production process, and can be adjusted in stages so as to effectively improve the deposition speed.
Aiming at the traditional process control mode, the control method of the application improves the deposition speed of the whole process of the reduction furnace 12 by dynamically adjusting the content of dichlorosilane and the content of silicon tetrachloride in the raw materials, and simultaneously controls the atomization effect of the reduction furnace 12 at the middle and later stages, thereby realizing efficient and high-quality production.
Compared with the prior art, the control method and the control system for producing the polysilicon in the embodiment have the beneficial effects that:
experimental data for different preset growth phases of the silicon rod are shown in table 1:
TABLE 1
1. According to the embodiment, through researching the operation characteristics of the silicon rod in the reduction furnace 12 in different growth stages, trichlorosilane raw materials containing dichlorosilane with different preset contents are introduced in different growth stages to perform hydrogen reduction reaction with hydrogen, so that the purpose of whole-course high-speed production of the reduction furnace 12 is achieved, the deposition speed of polycrystalline silicon can be improved, the silicon rod is prevented from growing more fragile, and the silicon rod is easy to fall into the furnace; but also can ensure the appearance quality of the polysilicon and reduce the atomization phenomenon.
2. According to the embodiment, silicon tetrachloride is added in a matching manner in the middle stage, dichlorosilane is consumed, the content of dichlorosilane is reduced, and the atomization effect in the middle-stage and later-stage reduction furnace 12 is restrained, so that the normal appearance quality of the reduction furnace 12 is ensured.
3. According to the embodiment, through increasing the monitoring of the atomization detector, the atomization phenomenon in the furnace can be further accurately controlled, and the quality of polysilicon is ensured.
Example 3
This embodiment provides a control method for producing polycrystalline silicon, which is different from embodiment 2 in that:
the temperature of the hydrogen reduction reaction in this example was 1050 ℃.
In this example, the volume ratio of trichlorosilane raw material containing dichlorosilane and hydrogen gas introduced into the reducing furnace is 1:2.
the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane in this example was 8mas%.
Example 4
This embodiment provides a control method for producing polycrystalline silicon, which is different from embodiment 2 in that:
the temperature of the hydrogen reduction reaction in this example was 1100 ℃.
In this example, the volume ratio of trichlorosilane raw material containing dichlorosilane and hydrogen gas introduced into the reducing furnace is 1:5.
the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane in this example was 10mas%.
It is to be understood that the above embodiments are merely illustrative of the application of the principles of the present application, but not in limitation thereof. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the application, and are also considered to be within the scope of the application.

Claims (6)

1. A control method for producing polycrystalline silicon, comprising the steps of:
introducing trichlorosilane raw materials and hydrogen into a reducing furnace for hydrogen reduction reaction, wherein the temperature of the hydrogen reduction reaction is 1050-1100 ℃, polysilicon is generated, the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride, and the trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride are introduced into the reducing furnace in different preset growth stages of a silicon rod, so that the deposition speed and atomization phenomenon of the polysilicon on the silicon rod are controlled;
in different preset growth stages of the silicon rod, the content of silicon tetrachloride in the trichlorosilane raw material is 1-5 mas;
the different preset growth stages of the silicon rod comprise: the first growth stage is within the first 30 hours, the second growth stage is 31-60 hours, the third growth stage is 61-100 hours, and the content of dichlorosilane in the trichlorosilane raw material is sequentially reduced in the three growth stages from the first growth stage to the third growth stage;
the method comprises the steps of introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into a reducing furnace in different preset growth stages of a silicon rod, wherein the method specifically comprises the following steps of:
the first growth stage is that during the first 30 hours, the content of dichlorosilane in the trichlorosilane raw material is 8-10 mas;
the second growth stage is 31-60 h, the content of dichlorosilane in the trichlorosilane raw material is 4-6mas, and the content of silicon tetrachloride is 3.1-5 mas;
the third growth stage is 61-100 h, the content of dichlorosilane in the introduced trichlorosilane raw material is 2-3mas, and the content of silicon tetrachloride is 1-3 mas%.
2. The method for controlling production of polycrystalline silicon according to claim 1, wherein the content of dichlorosilane in the trichlorosilane raw material is 2-10 mas% in different preset growth stages of the silicon rod.
3. The control method for producing polycrystalline silicon according to any one of claims 1 to 2, characterized in that the volume ratio of trichlorosilane raw material and hydrogen gas introduced into the reduction furnace is 1: (2-5).
4. The control method for producing polycrystalline silicon according to any one of claims 1 to 2, characterized in that the trichlorosilane raw material containing high-component dichlorosilane, the pure trichlorosilane raw material and the pure silicon tetrachloride raw material are respectively introduced into the reduction furnace, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8 to 10mas percent, and the dichlorosilane and the silicon tetrachloride in the trichlorosilane raw material introduced into the reduction furnace are adjusted to different preset contents.
5. A control system for use in the control method according to any one of claims 1 to 4, comprising:
the reduction furnace is used for introducing trichlorosilane raw materials and hydrogen into the reduction furnace for hydrogen reduction reaction to generate polysilicon, wherein the trichlorosilane raw materials are trichlorosilane raw materials containing dichlorosilane and silicon tetrachloride;
the adjusting device is connected with the reducing furnace and is used for introducing trichlorosilane raw materials with different preset contents of dichlorosilane and silicon tetrachloride into the reducing furnace in different preset growth stages of the silicon rod, so as to control the deposition speed and atomization phenomenon of the polysilicon on the silicon rod;
the atomization detection device is connected with the tail gas discharge pipeline of the reduction furnace, is used for detecting atomization phenomenon in the reduction furnace and is sent to the adjusting device; the adjusting device comprises:
the first pipeline is connected with the reduction furnace, a first regulating valve is arranged on the first pipeline, and the first pipeline is used for introducing a trichlorosilane raw material containing high-component dichlorosilane into the reduction furnace, wherein the content of dichlorosilane in the trichlorosilane raw material containing high-component dichlorosilane is 8-10 mas;
the second pipeline is connected with the reduction furnace, a second regulating valve is arranged on the second pipeline, and the second pipeline is used for introducing pure trichlorosilane raw materials into the reduction furnace;
the third pipeline is connected with the reduction furnace, a third regulating valve is arranged on the third pipeline, and the third pipeline is used for introducing pure silicon tetrachloride raw materials into the reduction furnace;
the control unit is respectively connected with the first regulating valve, the second regulating valve and the third regulating valve, and the control unit adjusts the opening degrees of the first regulating valve, the second regulating valve and the third regulating valve to different growth stages of the silicon rod, so that dichlorosilane and silicon tetrachloride in the trichlorosilane raw material entering the reducing furnace are different in preset content.
6. The control system of claim 5, wherein the adjusting means further comprises:
the fourth pipeline is connected with the reduction furnace, a fourth regulating valve is arranged on the fourth pipeline, the fourth pipeline is respectively connected with the first pipeline, the second pipeline and the third pipeline, and gas in the first pipeline, the second pipeline and the third pipeline flows into the reduction furnace through the fourth pipeline;
the fifth pipeline is connected with the reduction furnace, a fifth regulating valve is arranged on the fifth pipeline, the fifth pipeline is used for introducing hydrogen into the reduction furnace, the control unit is respectively connected with the fourth regulating valve and the fifth regulating valve, and the control unit regulates the volume ratio of trichlorosilane raw materials and hydrogen which are introduced into the reduction furnace to be a preset volume ratio by respectively controlling the opening degrees of the fourth regulating valve and the fifth regulating valve.
CN202210759614.2A 2022-06-29 2022-06-29 Control method and control system for producing polycrystalline silicon Active CN115092931B (en)

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CN102188941A (en) * 2010-02-12 2011-09-21 通用电气公司 System and method for operating catalytic reforming assembly of engine system of combustion gas turbine
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