CN102030330A - Polysilicon reduction furnace with outlet gas collector - Google Patents

Abstract

The invention discloses a polysilicon reduction furnace with an outlet gas collector, comprising a furnace body, a clamping sleeve, a chassis, a support, an observation sight glass, a plurality of electrode pairs, a silicon core, a gas mixture intake pipe, an intake nozzle, an outlet gas collector, a gas outlet pipe, a cooling system and the like. The polysilicon reduction furnace is characterized in that the top end in the furnace is provided with the outlet gas collector, and the center of the chassis is provided with the gas outlet pipe which is communicated with the outlet gas collector. The outlet gas collector is provided with two main connecting pipes which are vertically communicated. One end of a main connecting pipe I is communicated with the gas outlet pipe in the center of the chassis, and the other end of the main connecting pipe I is vertically communicated with the center position of a main connecting pipe II. The main connecting pipe II is vertically communicated with a plurality of side-connecting pipes, and the side-connecting pipes and the downward surface of the main connecting pipe II are provided with a plurality of small holes. The arrangement of the outlet gas collector ensures that gas in the furnace is not easily short-circuited and is uniformly distributed, and the gas contacts with a high-temperature silicon rod to react, therefore the uniform thickness of the upper part and the lower part of a generated polysilicon rod is finally ensured, and the product quality is improved.

Description

Polysilicon reduction furnace with outlet gas collector

technical field

The invention relates to a polysilicon production equipment, in particular to a polysilicon reduction furnace.

Background technique

At present, polysilicon production enterprises mainly adopt the improved Siemens method. The production process of this method is to use chlorine and hydrogen to synthesize hydrogen chloride (or purchased hydrogen chloride), hydrogen chloride and metallurgical silicon powder to synthesize trichlorosilane at a certain temperature, and the trichlorosilane after separation and rectification purification enters the reduction furnace and is reduced by hydrogen , to produce high-purity polysilicon by chemical vapor deposition reaction. The process includes five main links: synthesis of trichlorosilane, rectification and purification of trichlorosilane, hydrogen reduction of trichlorosilane, recovery of tail gas and hydrogenation separation of silicon tetrachloride.

Among them, the hydrogen reduction of trichlorosilane is carried out in a large bell-type reduction furnace. The reduction furnace is mainly composed of furnace body, silicon core, gas system, electrode heating system and cooling system, as shown in Figure 2. The mixed gas of hydrogen and trichlorosilane enters the reduction furnace through the inlet pipe and the nozzles set on it. During the process of high-speed upward jetting of the mixed gas, a chemical vapor deposition reaction occurs on the surface of the energized and high-temperature silicon core to form high-purity polysilicon, and a rod-shaped polysilicon product is obtained. , and at the same time generate silicon tetrachloride, dichlorodihydrosilane, hydrogen chloride and other by-product tail gas, and the tail gas is discharged from the gas outlet and the gas outlet pipe set on the chassis.

The main problems existing in the prior art are: the setting of the gas circuit system is unreasonable, as shown in Figure 2, the air inlet 9 and the air outlet 10' are both arranged on the chassis of the reduction furnace, causing a short circuit at the bottom of the furnace due to gas diffusion , Part of the gas is directly discharged through the gas outlet without fully contacting with the silicon core to react, and the gas distribution in the furnace is uneven, which eventually leads to uneven thickness of the generated polysilicon rods, which affects product quality. Whether the tail gas can be evenly collected and discharged has a great influence on the operation performance of the reduction furnace and the quality of the polysilicon rod product, so it is necessary to redesign the gas outlet structure of the reduction furnace. The improved polysilicon reduction furnace disclosed in Chinese patent CN201105995Y is characterized in that an exhaust gas outlet duct is added to the chassis so that the gas outlet and the inlet position are not on the same plane; Furnace, the gas outlet is set on the top of the reduction furnace, adopting a structure of 5 to 7 nozzles. Although these structural changes can improve the phenomenon of short circuit caused by gas diffusion at the bottom in traditional reduction furnaces, they have not fundamentally solved the problem of uneven gas distribution in the furnace.

Contents of the invention

The purpose of the polysilicon reduction furnace with an outlet gas collector of the present invention is to overcome the above-mentioned shortcomings of the existing equipment, and to provide a polysilicon that can make the gas in the furnace less prone to short circuit and evenly distributed so as to ensure that the produced polysilicon rods are uniform in thickness up and down. reduction furnace.

The present invention is achieved through the following technical solutions:

A polysilicon reduction furnace of the present invention comprises a furnace body, a jacket, a chassis, a support, a plurality of pairs of electrodes, a silicon core with a graphite head, a mixed gas inlet pipe and an inlet nozzle, an air outlet pipe and a cooling system, etc.; An outlet gas collector is arranged at the top of the furnace, and an outlet pipe is arranged at the center of the chassis, and the outlet pipe communicates with the outlet gas collector.

The outlet gas collector is provided with two vertically connected main pipes; one end of the main pipe I 19 communicates with the outlet pipe arranged in the center of the chassis, and the other end communicates vertically with the center of the main pipe II 20; the main pipe II is connected There are several side connecting pipes 21, and the side connecting pipes are vertically connected with the main connecting pipe II; the downward side of the side connecting pipes and the main connecting pipe II, that is, the side facing the chassis, is uniformly provided with a number of small holes 22.

The main connecting pipe II 20 and the side connecting pipe 21 are all connected with the furnace body 1 inner wall.

The main connecting pipe II 20 and the side connecting pipe 21 are all connected with the furnace body 1 inner wall by lap plates 24 and bolts 25.

Multiple pairs of electrodes are evenly arranged on the chassis in positive and negative staggered circles, and the tops of the silicon cores with graphite heads connected to the electrodes are overlapped in pairs. The electrodes can be set to 12 pairs, 15 pairs, 18 pairs, 24 pairs, or 36 pairs. ; A number of nozzles are connected to the gas mixture intake pipe, and the nozzles are evenly distributed on the chassis.

The specific instructions are as follows:

Polysilicon reduction furnace with outlet gas collector, including furnace body, jacket, chassis, support, observation mirror, multiple pairs of electrodes, silicon core with graphite head, mixed gas inlet pipe and inlet nozzle, outlet gas Collector, air outlet pipe, jacket cooling water inlet and outlet, chassis cooling water inlet and outlet, electrode cooling water inlet and outlet and other accessories. Multiple pairs of electrodes are evenly arranged on the chassis in positive and negative staggered circles, and the tops of the silicon cores with graphite heads connected to the electrodes are overlapped in pairs. The electrodes can be set to 12 pairs, 15 pairs, 18 pairs, 24 pairs, or 36 pairs. A number of nozzles are connected to the mixed gas inlet pipe, and the nozzles are evenly distributed on the chassis; an outlet gas collector is arranged at the top of the furnace, and an outlet pipe is arranged at the center of the chassis, and the outlet pipe communicates with the outlet gas collector.

The outlet gas collector is provided with two vertically connected main pipes; one end of the main pipe I 19 communicates with the outlet pipe 11 arranged in the center of the chassis, and the other end communicates vertically with the center of the main pipe II 20; A plurality of side connecting pipes 21 are connected, and the side connecting pipes 21 are vertically communicated with the main connecting pipe II 20; the downward side of the side connecting pipe 21 and the main connecting pipe II 20, that is, the side facing the chassis, is evenly provided with some small holes 22. Main takeover I 19 is connected with main takeover II 20, main takeover II 20 and side takeover 21 through flange 23, and main takeover II 20 and side takeover 21 are all connected with furnace body 1 inner wall by lap plate 24 and bolt 25.

The present invention is characterized in that an outlet gas collector is arranged at the top of the polysilicon reduction furnace, and an outlet pipe arranged at the center of the chassis communicates with the outlet gas collector.

The effect and advantage of the present invention are that the mixed gas of hydrogen and trichlorosilane enters the reduction furnace through the inlet pipe and the inlet nozzle, because the top of the furnace is provided with an outlet gas collector, and the outlet gas collector is connected with the outlet gas collector arranged at the center of the chassis. The gas outlet pipe is connected so that the gas can be discharged directly from the gas outlet without short circuit during the process of high-speed upward injection, and can be evenly distributed in the entire furnace space, fully contacting the electrified high-temperature silicon rod and generating a chemical gas phase on its surface The deposition reaction produces high-purity polysilicon that is uniformly deposited on the silicon rod, and a rod-shaped polysilicon product with uniform thickness from top to bottom is obtained. Simultaneously generated by-product tail gas such as silicon tetrachloride, dichlorodihydrosilane, and hydrogen chloride moves upward to the outlet gas collector, enters the collector through a number of small holes uniformly arranged on the lower surface of the collector, and then flows along the main body of the collector. Connect pipe I and move downwards until the outlet pipe is discharged.

Description of drawings

Fig. 1 is the structural representation of the polysilicon reduction furnace with outlet gas collector of the present invention;

Fig. 2 is the structural representation of existing polysilicon reduction furnace;

Fig. 3 is the structural representation of outlet gas collector of the present invention;

Fig. 4 is the A-A structural representation of outlet gas collector of the present invention;

Among them: 1-furnace body, 2-jacket, 3-chassis, 4-support, 5-silicon core, 6-electrode, 7-graphite head, 8-intake pipe, 9-intake nozzle, 10-outlet gas Collector, 10'-air outlet, 11-air outlet pipe, 12-observation mirror, 13-jacket cooling water inlet, 14-jacket cooling water outlet, 15-chassis cooling water inlet, 16-chassis cooling water outlet, 17-electrode cooling water inlet, 18-electrode cooling water outlet, 19-exit gas collector main connection I, 20-exit gas collector main connection II, 21-exit gas collector side connection, 22-exit gas collector small Hole, 23-flange, 24-lap plate, 25-bolt.

Detailed ways

The present invention will be described in further detail below according to accompanying drawing:

As shown in Figure 1, a polysilicon reduction furnace with an outlet gas collector includes a furnace body 1, a jacket 2, a chassis 3, a support 4, an observation mirror 12, multiple pairs of electrodes 6, and a silicon core with a graphite head 7 5. Mixed gas inlet pipe 8 and inlet nozzle 9, outlet gas collector 10, air outlet pipe 11, jacket cooling water inlet 13, jacket cooling water outlet 14, chassis cooling water inlet 15, chassis cooling water Water outlet 16, electrode cooling water inlet 17, electrode cooling water outlet 18, etc. Multiple pairs of electrodes 6 are evenly arranged on the chassis in positive and negative staggered circles, and the tops of the silicon cores 5 with graphite heads 7 connected to the electrodes 6 are overlapped in pairs. The electrodes 6 can be set to 12 pairs, 15 pairs, or 18 pairs or 24 pairs or 36 pairs; the mixed gas inlet pipe 8 is connected with a number of nozzles 9, and the nozzles 9 are evenly distributed on the chassis; the top of the furnace is provided with an outlet gas collector 10, and the center of the chassis is provided with an outlet pipe 11, which is connected with the outlet gas The collector 10 communicates.

As shown in Fig. 3 and Fig. 4, the outlet gas collector 10 is provided with two main connecting pipes vertically connected, wherein one end of the main connecting pipe I19 is communicated with the air outlet pipe 11, and the other end is vertically connected with the central position of the main connecting pipe II 20; The connecting pipe II 20 is provided with several side connecting pipes 21, and the side connecting pipes 21 are vertically communicated with the main connecting pipe II 20; the downward side of the side connecting pipes 21 and the main connecting pipe II 20, that is, the side facing the chassis, is evenly provided with some small holes 22. Main takeover I 19 is connected with main takeover II 20, main takeover II 20 and side takeover 21 through flange 23, and main takeover II 20 and side takeover 21 are all connected with furnace body 1 inner wall by lap plate 24 and bolt 25.

The mixed gas of hydrogen and trichlorosilane is sprayed into the reduction furnace 1 through the inlet pipe 8 and several nozzles 9 arranged on it at high speed, and the silicon core electrode 6 with the graphite head 7 is energized to generate high temperature. Between 13 and the water outlet 14, between the chassis cooling water inlet 15 and the water outlet 16, between the electrode cooling water inlet 17 and the water outlet 18, cooling water is passed. The gas is ejected upward at high speed, and the gas collector 10 at the top outlet of the furnace ensures that the mixed gas is not easy to short-circuit and is evenly distributed in the entire furnace space, fully in contact with the energized high-temperature silicon core 5, and chemical vapor deposition reaction occurs on the surface of the silicon core 5 , generate high-purity polysilicon and deposit it on the silicon core, and obtain rod-shaped polysilicon products with uniform thickness up and down. The by-product tail gas such as silicon tetrachloride, dichlorodihydrosilane, and hydrogen chloride generated in the reaction moves upward to the outlet gas collector 10 at the top of the furnace, and enters the collector from a number of small holes 22 uniformly arranged on the lower surface of the collector. Then move down to the air outlet pipe 11 at the center of the chassis along the main connecting pipe 119 of the collector to discharge. Three observation mirrors 12 are arranged from top to bottom on the side wall of the furnace body to facilitate observation of the growth conditions of various parts of the polycrystalline silicon rod.

Claims (5)

1. a polycrystalline silicon reducing furnace comprises body of heater, chuck, and the chassis, bearing, many counter electrode have the silicon core of graphite head, gas mixture inlet pipe and nozzle of air supply, escape pipe and cooling system; It is characterized in that the top is provided with the exit gas collector in the stove, center chassis is provided with escape pipe, and escape pipe is communicated with the exit gas collector.

2. polycrystalline silicon reducing furnace according to claim 1 is characterized in that the exit gas collector is provided with the main of two vertical connections and takes over; Wherein main adapter I (19) one ends are communicated with the escape pipe that is arranged on center chassis, the other end and the main central position vertical connection of taking over II (20); The main adapter on the II is connected with some side joint pipes (21), and side joint Guan Yuzhu takes over the II vertical connection; Side joint pipe and the main downward one side of II of taking over promptly evenly are provided with some apertures (22) towards the one side on chassis.

3. polycrystalline silicon reducing furnace according to claim 2 is characterized in that the main II of adapter (20) is connected with body of heater (1) inwall with some side joint pipes (21).

4. polycrystalline silicon reducing furnace according to claim 3 is characterized in that the main II 20 of adapter is connected with body of heater (1) inwall by lap plate (24) and bolt (25) with side joint pipe 21.

5. polycrystalline silicon reducing furnace according to claim 1, it is characterized in that many counter electrode divide positive and negative interlocking of circle to be arranged on the chassis equably, the silicon core top that has graphite head that is connected with electrode overlaps in twos, and electrode is set to 12 pairs or 15 pairs or 18 pairs or 24 pairs or 36 pairs; Connect plurality of nozzles on the gas mixture inlet pipe, nozzle is evenly distributed on the chassis.

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