JP2023128581A - Manufacturing facility of single crystal silicon ingot and manufacturing method of single crystal silicon ingot - Google Patents

Abstract

To provide a manufacturing facility of a single crystal silicon ingot and a manufacturing method of the single crystal silicon ingot, capable of promoting the combustion of oxide deposited in an exhaust pipe.SOLUTION: A manufacturing facility 1 of a single crystal silicon ingot includes: an exhaust pipe conduit 3 connected to a manufacturing apparatus 2; and a vacuum pump 4 for sucking inert gas supplied into the manufacturing apparatus 2 through the exhaust pipe conduit 3, wherein the exhaust pipe conduit 3 is composed of a first exhaust pipe 3a connected to an exhaust gas port 6 of the manufacturing apparatus 2 and a second exhaust pipe 3b connecting between the first exhaust pipe 3a and the vacuum pump 4, and further includes: a first air supply part 7 connected to the first exhaust pipe 3a for supplying air into the first exhaust pipe 3a; and a second air supply part 9 connected to the second exhaust pipe 3b for supplying air into the second exhaust pipe 3b. A manufacturing method of the single crystal silicon ingot includes supplying air to the inert gas flowing in the exhaust pipe conduit 3 to combust oxide in the exhaust pipe conduit 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to equipment for manufacturing single-crystal silicon ingots and a method for manufacturing single-crystal silicon ingots.

The Czochralski method (CZ method) can be cited as a typical manufacturing method for single-crystal silicon ingots. In manufacturing single-crystal silicon ingots using the CZ method, a quartz crucible is filled with silicon raw materials such as polycrystalline silicon, and the silicon raw materials are heated and melted in a chamber of a single-crystal silicon ingot manufacturing device under an inert gas atmosphere. to obtain a silicon melt. Next, by bringing the seed crystal into contact with the silicon melt in the quartz crucible and gradually raising the seed crystal while rotating the seed crystal and the quartz crucible in a predetermined direction, a single crystal silicon ingot is placed below the seed crystal. Develop. Exhaust equipment for exhausting the inert gas supplied into the chamber is connected to the single-crystal silicon ingot manufacturing equipment, and an exhaust gas port is provided at the bottom of the single-crystal silicon ingot manufacturing equipment. It passes through an exhaust pipe, is sucked in by a vacuum pump, and is discharged.

A multiplexing method is known as an application of the above CZ method. In the multi-pulling method, after pulling the first single-crystal silicon ingot, additional silicon raw material is charged and melted in the same quartz crucible, and the second single-crystal silicon ingot is pulled from the resulting silicon melt. conduct. By repeating such a raw material filling process and a pulling process, a plurality of single crystal silicon ingots are manufactured from one quartz crucible. According to the multi-pulling method, the cost of a quartz crucible per single crystal silicon ingot can be reduced. Furthermore, since the frequency of dismantling the chamber and replacing the quartz crucible can be reduced, operational efficiency can be improved.

When pulling a single-crystal silicon ingot using the CZ method, oxygen dissolves into the silicon melt from the inner surface of the quartz crucible, reacts with the silicon melt, produces oxides (SiOx), and evaporates from the silicon melt surface. do. These oxides flow through the exhaust pipe together with the inert gas in the single-crystal silicon ingot manufacturing equipment and are collected in the dust chamber, but because the exhaust pipe from the exhaust gas port to the dust chamber is long, As the oxides flow through the exhaust pipe, they are cooled and condensed, and over time they adhere and accumulate on the exhaust pipe. For this reason, there is a tendency for a large amount of oxide to be deposited on the rear dust chamber side rather than on the front exhaust gas port side of the exhaust pipe.

In the CZ method, since the manufacturing time per cylinder is long, the problem is that oxides accumulate inside the exhaust pipe. In other words, when the amount of oxide deposited in the exhaust pipe increases, the deposited oxide may flow back from the exhaust pipe to the single-crystal silicon ingot manufacturing equipment, causing the single-crystal silicon ingot to have dislocations, or the oxides may adhere to the inside of the exhaust pipe. There is a risk that the pressure will fluctuate and the temperature and pressure will rise rapidly, causing the oxide to catch fire.

On the other hand, it has been proposed to supply air into the exhaust pipe to burn the oxides deposited in the exhaust pipe after completing pulling of the single crystal silicon ingot (for example, Patent Documents 1 and 2). According to this, it is possible to reduce the amount of oxide deposited in the exhaust pipe after the pulling of the single crystal silicon ingot is completed.

Japanese Patent Application Publication No. 2001-097797 Japanese Patent Application Publication No. 2002-316889

However, when a single crystal silicon ingot becomes dislocated during pulling and the pulled single crystal silicon ingot is re-pulled after being remelted, or when multiple single crystal silicon ingots are pulled from a single quartz crucible using the multi-pulling method. This will increase the operating time until the lifting is completed.
As the operating time increases, the amount of oxide deposited in the exhaust pipe also increases, so even if the oxide combustion operation is performed after the pulling of the single crystal silicon ingot is completed, as described in Patent Documents 1 and 2, , cannot be carried out during lifting. Therefore, the oxide in the exhaust pipe cannot be sufficiently combusted by the time the single-crystal silicon ingot is pulled, and there is a risk that the pressure in the exhaust pipe may change or a sudden ignition may occur.

In addition, since the exhaust pipe line from the exhaust gas port at the bottom of the monocrystalline silicon ingot production equipment to the dust chamber is long, after the monocrystalline silicon ingot has been pulled, the power supply for the heater in the monocrystalline silicon ingot production equipment must be If air is supplied and a combustion operation is performed after the vacuum pump is turned off, the oxides in the exhaust pipe close to the monocrystalline silicon ingot production equipment will be burned, but the oxides in the exhaust pipe far away from the vacuum pump will be burned. There were some cases where the fuel was not fully combusted. This is because immediately after the heater power is turned off, the combustion reaction of oxides tends to occur on the exhaust pipe side near the single-crystal silicon ingot manufacturing equipment because the temperature inside the pipe is relatively high, while the This is thought to be due to the fact that the temperature inside the pipe is low on the exhaust pipe side, which is closer to the exhaust pipe, making it difficult for the combustion reaction of oxides to occur. As described above, it has become clear that the oxide cannot be sufficiently burned over the entire length of the exhaust pipe by the combustion operation using air supply, which is performed after the pulling is completed and the heater power is turned off.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a single-crystal silicon ingot manufacturing facility and a single-crystal silicon ingot manufacturing method that can promote the combustion of oxides deposited in an exhaust pipe.

The present inventors have recalled that the above-mentioned problem can be advantageously solved by supplying air to a predetermined portion of the exhaust pipe line in a predetermined step during pulling of a single crystal silicon ingot. In the present invention, "air" refers to the totality of gases surrounding the earth, including oxygen, nitrogen, hydrogen, argon, carbon dioxide, ozone, neon, helium, water vapor, etc. do.

The gist of the present invention is as follows.
(1) An exhaust pipe connected to a single crystal silicon ingot manufacturing device,
A single-crystal silicon ingot manufacturing facility, comprising: a vacuum pump that sucks inert gas supplied into the single-crystal silicon ingot manufacturing device through the exhaust pipe,
The exhaust pipe line includes a first exhaust pipe connected to an exhaust gas port of the single crystal silicon ingot manufacturing apparatus, and a second exhaust pipe connecting the first exhaust pipe and the vacuum pump. , consisting of;
a first air supply unit connected to the first exhaust pipe and supplying air into the first exhaust pipe;
A single-crystal silicon ingot manufacturing facility, comprising: a second air supply unit connected to the second exhaust pipe and supplying air into the second exhaust pipe.

(2) the second exhaust pipe is provided with a pressure adjustment section that adjusts the pressure within the first exhaust pipe;
When the exhaust gas port side is the front side of the exhaust pipe and the vacuum pump side is the rear side of the exhaust pipe, the second air supply section is connected to the rear side of the pressure adjustment section. The single crystal silicon ingot manufacturing equipment according to (1) above.
Note that the "front side" includes not only the inside of the second exhaust pipe but also the inside of the first exhaust pipe.

(3) A method for producing a single crystal silicon ingot by the Czochralski method, comprising:
a raw material melting step of heating and melting silicon raw material filled in a quartz crucible;
a liquid deposition step of lowering a seed crystal to deposit it on the silicon melt in the quartz crucible;
a single crystal growth step of pulling a single crystal silicon ingot from the silicon melt in the quartz crucible;
A single crystal cooling step of cooling the grown single crystal silicon ingot,
In any one or more of the liquid deposition step, the single crystal growth step, and the single crystal cooling step, air is introduced into an inert gas flowing in an exhaust pipe connected to a manufacturing device for a single crystal silicon ingot. A method for producing a single-crystal silicon ingot, characterized in that the oxides in the exhaust pipe are burned by supplying the same.

(4) A method for manufacturing the single crystal silicon ingot according to the above (3) by the Czochralski method using the single crystal silicon ingot manufacturing equipment according to the above (1) or (2),
In any one or more of the liquid deposition step, the single crystal growth step, and the single crystal cooling step, air is supplied from the second air supply section to the inert gas flowing in the second exhaust pipe. and burning the oxide in the second exhaust pipe.

(5) A method for manufacturing a single crystal silicon ingot according to the above (4) using the single crystal silicon ingot manufacturing equipment according to the above (2),
The pressure inside the first exhaust pipe that occurs when air is supplied into the second exhaust pipe is measured, and the pressure inside the first exhaust pipe is adjusted by the pressure adjustment section based on the measured pressure fluctuation value. A method for producing a single crystal silicon ingot.

(6) manufacturing a plurality of single crystal silicon ingots using the same quartz crucible by repeating the raw material melting process, the liquid deposition process, the single crystal growth process, and the single crystal cooling process; The method for producing a single crystal silicon ingot according to any one of (3) to (5) above, which involves performing a multiple pulling method.

(7) When producing a plurality of monocrystalline silicon ingots, the second air supply section supplies air into the second exhaust pipe for each monocrystalline silicon ingot produced. The method for producing a single crystal silicon ingot according to (6) above, wherein the oxide in the second exhaust pipe is burned.

(8) After the single-crystal cooling process of the single-crystal silicon ingot and before returning the chamber of the single-crystal silicon ingot manufacturing apparatus to normal pressure, the first air supply unit connects the first exhaust pipe to the first exhaust pipe. The method for producing a single crystal silicon ingot according to any one of (3) to (7) above, wherein air is supplied into the pipe to burn the oxide in the first exhaust pipe.

(9) After the single-crystal cooling step of the single-crystal silicon ingot, and before returning the inside of the chamber of the single-crystal silicon ingot manufacturing apparatus to normal pressure, the first air supply section and the second air supply section (3) to (3) above, wherein air is supplied into the first exhaust pipe and the second exhaust pipe to burn the oxides in the first exhaust pipe and the second exhaust pipe. 7) The method for producing a single crystal silicon ingot according to any one of 7).

According to the present invention, it is possible to provide single-crystal silicon ingot manufacturing equipment and a single-crystal silicon ingot manufacturing method that can promote the combustion of oxides deposited in an exhaust pipe.

FIG. 1 is a schematic diagram showing a single crystal silicon ingot manufacturing facility according to an embodiment of the present invention. 1 is a flowchart of a method for manufacturing a single crystal silicon ingot according to an embodiment of the present invention. 1 is a schematic diagram showing a manufacturing facility for a single crystal silicon ingot used in Comparative Example 1. FIG. FIG. 2 is a schematic diagram showing a manufacturing facility for single-crystal silicon ingots used in Comparative Examples 2 and 3.

Hereinafter, embodiments of the present invention will be illustrated in detail with reference to the drawings.

<Single crystal silicon ingot manufacturing equipment>
FIG. 1 is a schematic diagram showing a single-crystal silicon ingot manufacturing facility according to an embodiment of the present invention. As shown in FIG. 1, the single-crystal silicon ingot manufacturing equipment 1 of the present embodiment includes an exhaust pipe line 3 connected to a single-crystal silicon ingot manufacturing apparatus 2, and a single-crystal silicon ingot manufacturing apparatus through the exhaust pipe line 3. The vacuum pump 2 includes a vacuum pump 4 that sucks inert gas supplied into the chamber 2, and a dust chamber 11 that collects oxides. The single crystal silicon ingot manufacturing apparatus 2 is installed in a clean room C. R. Inner floor F. L. Directly above the floor F. L. A vacuum pump 4 and a dust chamber 11 are located below the clean room C. R. Pump room outside P. R. are located respectively.

The single crystal silicon ingot manufacturing apparatus 2 includes a main chamber 2a and a pull chamber 2b connected to the upper end of the main chamber 2a. Although not shown, the main chamber 2a houses a quartz crucible in which a silicon melt is stored, a heater that surrounds the quartz crucible, and heats the silicon melt, and the like. Further, a pulling means 2c for pulling up the single crystal silicon ingot is provided at the upper end of the pull chamber 2b. The vacuum pump 4 is connected to the lower surface of the main chamber 2a through the exhaust pipe line 3. Further, an inert gas supply conduit 5a is connected to the pull chamber 2b. The inert gas supply conduit 5a is connected to the upper and lower surfaces of the pull chamber 2b via switch valves 5b and 5c, and the inert gas supply conduit 5a is used to store inert gas (Ar gas in this example). It is also connected to a tank (not shown). The switch valves 5b and 5c are, for example, electrically operated, and are configured to be able to control the pressure inside the main chamber 2a by adjusting the flow rate of Ar gas, respectively.

As shown in FIG. 1, the exhaust pipe line 3 includes a first exhaust pipe 3a connected to the exhaust gas port 6 of the single crystal ingot manufacturing apparatus 2, and a space between the first exhaust pipe 3a and the vacuum pump 4. and a connected second exhaust pipe 3b. The first exhaust pipe 3a has a pair of a first branch pipe 3a1 and a second branch pipe 3a2, one end of which is connected to the lower surface of the main chamber 2a and the other end of which joins, and one end of which is a first branch pipe 3a2. 3a1 and a third branch pipe 3a3 which is connected to the second branch pipe 3a2 and whose other end is connected to the flapper valve 13. When the oxides deposited in the exhaust pipe 3 burn and the pressure in the exhaust pipe 3 rises rapidly, the flapper valve 13 is operated to release the pressure in the exhaust pipe 3.

This single-crystal silicon ingot manufacturing facility 1 includes a first air supply section 7 that is connected to a first exhaust pipe 3a and supplies air into the first exhaust pipe 3a. The first air supply section 7 is a switch valve in this example. The switch valve can be, for example, a two-port, two-position electromagnetic valve, and is configured so that when turned on, the switch valve opens and when turned off, the switch valve closes. Note that in this example, the above-described operation of the first air supply section 7 can be controlled by the control section 12. As the control unit 12, any known controller can be used.

This single crystal silicon ingot manufacturing facility 1 further includes a second air supply section 9 that is connected to the second exhaust pipe 3b and supplies air into the second exhaust pipe 3b. The second air supply section 9 is a control valve in this example. In this example, the operation of the second air supply section 9 can be controlled by the control section 12 described above. It is preferable that the second air supply unit 9 is capable of highly controlling the amount and timing of air supply, and for example, it may use not only a solenoid valve but also a ball valve or a flow meter. I can do it.
It is considered that if the air supply speed is too high, a dust cloud is likely to be generated in the exhaust pipe 3, and a dust explosion is likely to occur due to rapid combustion of oxides. Since the second air supply section 9 is only a vacuum solenoid valve, it supplies air all at once, which may cause a dust explosion. Therefore, it is preferable to add a silencer and a ball valve that can be opened slowly (open over 10 seconds) so that the air supply does not occur all at once. In addition, if the total exhaust amount of the Ar gas flow rate and air supply amount is too large and exceeds the exhaust capacity of the vacuum pump 4 (for example, the exhaust capacity when the furnace pressure is 30 Torr is 592 L/min), the pump overflow may occur. This may cause a load and cause the pump to stop or malfunction. Therefore, it is also preferable to add a flow meter with a flow rate adjustment function next to the vacuum solenoid valve so that the air supply amount does not exceed 200 L/min.

In the single crystal silicon ingot manufacturing facility 1 of this embodiment, the second exhaust pipe 3b is equipped with a pressure adjustment section 8 that adjusts the pressure inside the first exhaust pipe 3a. Although the pressure regulator 8 is a control valve in this example, it is preferable to use a butterfly valve or the like.
By providing the pressure adjustment section 8, pressure fluctuations within the first exhaust pipe 3a that occur when air is supplied from the second air supply section 9 into the second exhaust pipe 3b during pulling of the single crystal silicon ingot can be reduced. can be suppressed. As a result, pressure fluctuations in the main chamber 2a can be prevented, and oxides deposited in the second exhaust pipe 3b during pulling of the single crystal silicon ingot can be burned without causing backflow of exhaust gas into the main chamber 2a. operations can be performed.

In this example, when the exhaust gas port 6 side is the front side of the exhaust pipe 3 and the vacuum pump 4 side is the rear side of the exhaust pipe 3, the second air supply section 9 is located on the rear side of the pressure adjustment section 8. It is connected to the. For example, in this example, the pressure adjustment section 8 is installed at the tip side (front side) of the second exhaust pipe 3b, and the second air supply section 9 is installed immediately after the pressure adjustment section 8. More specifically, the distance is set so that the oxide can be burned by the second air supply section 9, and this distance can be set as appropriate. More specifically, the distance from the pressure adjustment section 8 to the second air supply section 9 (the distance along the route of the exhaust pipe line 3) is 50% or less of the distance from the pressure adjustment section 8 to the vacuum pump 4. It is preferable that The closer the air supply position is to the vacuum pump 4 side, the lower the temperature inside the exhaust pipe line 3 and the lower the temperature of the oxide, so the ignition phenomenon itself to burn the oxide tends to occur less easily. By arranging the second exhaust pipe 3 at a position close to the pressure regulating part 8 where the temperature inside the second exhaust pipe 3b is relatively high, the ignitability of oxides by air supply is improved, and the oxides deposited in the second exhaust pipe 3b can be burned. can.

In this example, a pressure gauge 10 is arranged immediately before the pressure adjustment section 8, which measures the pressure in the chamber 2a by measuring the pressure in the first exhaust pipe 3a. The measured value of the pressure gauge 10 is transmitted to the control section 12, and the pressure adjustment section 8 is controlled based on the pressure fluctuation of the first exhaust pipe 3a obtained from the measurement value.

As the vacuum pump 4, a combination of a water ring pump and a mechanical booster, an oil rotary pump, a dry vacuum pump, or the like is used. In this example, a dust chamber 11 is provided immediately before the vacuum pump 4, in which oxides can be separated from the inert gas sucked in by the cyclone 14 and collected in this dust chamber 11.

<Method for manufacturing single crystal silicon ingot>
FIG. 2 is a flowchart of a method for manufacturing a single crystal silicon ingot according to an embodiment of the present invention. As shown in FIG. 2, in the method for manufacturing a single-crystal silicon ingot according to the present embodiment, a quartz crucible located in the main chamber 2a is first filled with a silicon raw material such as a polycrystalline silicon nugget (Step S101: Filling the raw material process).

Next, the atmosphere inside the main chamber 2a is exhausted to make the main chamber 2a a vacuum (step S102: vacuum step in the chamber). When exhausting the atmosphere inside the main chamber 2a, the pressure adjustment section 8 is fully opened.

Next, the silicon raw material filled in the quartz crucible is heated and melted (step S103: raw material melting step). Specifically, the silicon raw material in the quartz crucible is heated and melted by a heater while flowing Ar, which is an inert gas, to form a silicon melt in the quartz crucible. After that, the quartz crucible is raised to the pulling start position.

Next, the seed crystal is lowered and deposited on the silicon melt in the quartz crucible (step S104: deposition step). For example, this can be done by lowering the pulling wire using a wire lifting mechanism or the like.

Next, the single crystal silicon ingot is pulled out of the silicon melt in the quartz crucible (step S105: single crystal growth step). Specifically, while rotating the quartz crucible and the pulling wire in a predetermined direction, the pulling wire is pulled upward to grow a single crystal silicon ingot below the seed crystal. Note that as the growth of the ingot progresses, the amount of silicon melt decreases, but the quartz crucible is raised to maintain the level of the silicon melt surface.

As shown in FIG. 2, the single crystal growth step (step S105) includes the following steps. In the single crystal growth step, first, in order to make the single crystal silicon ingot dislocation-free, seed squeezing (necking) is performed by the dash neck method to form a necked portion (step S105-1: necked portion growth step). Next, a shoulder portion is grown to obtain an ingot with a required diameter (step S105-2: shoulder portion growing step). Next, when the single crystal silicon ingot reaches a desired diameter, a body portion is grown while keeping the diameter constant (step S105-3: body portion growth step). Next, after growing the body part to a predetermined length, tail drawing is performed to separate the single crystal silicon ingot from the silicon melt in a dislocation-free state to form a tail part (Step S105-4: Tail part growing step ).

Next, the grown single crystal silicon ingot is cooled (step S106: single crystal cooling step). For example, the single-crystal silicon ingot is left in the pull chamber 2b with the valve closed until it reaches a take-out temperature of preferably 500° C. or less, and then cooled.

This embodiment uses the same quartz crucible by repeating the raw material melting process (step S103), the liquid deposition process (step S104), the single crystal growth process (step S105), and the single crystal cooling process (step S106). This method uses a multiple-pulling method to produce multiple single-crystal silicon ingots. In step S107, it is determined whether or not to perform the next pulling (eg, based on the planned number of single crystal silicon ingots to be manufactured).

When performing the next pulling, the inside of the pull chamber 2b is returned to normal pressure (step S108), the single crystal silicon ingot is taken out (step S109), and the process returns to step S101 to obtain the next single crystal silicon ingot. Manufactures single crystal silicon ingots.

On the other hand, if the next lifting is not to be performed, first, the power to the heater is turned off (step S110). Then, the main chamber 2a and the pull chamber 2b are returned to normal pressure (step S112), the single crystal silicon ingot is taken out (step S113), and the manufacturing is completed. Here, in the method of the present embodiment, after the single crystal cooling step of the single crystal silicon ingot (step S106), before returning the inside of the chamber of the single crystal silicon ingot manufacturing apparatus 2 to normal pressure (prior to step S112) , the inside of the first exhaust pipe 3a, or the first exhaust pipe 3a and the second exhaust pipe 3b, by the first air supply section 7, or the first air supply section 7 and the second air supply section 9. The process further includes supplying air (step S111) to combust the oxides in the first exhaust pipe 3a, or the first exhaust pipe 3a and the second exhaust pipe 3b.

In this embodiment, in any one or more of the liquid deposition process (step S104), the single crystal growth process (step S105), and the single crystal cooling process (step S106), the inside of the exhaust pipe 3 (in this example, Air is supplied (from the second air supply section 9 in this example) to the inert gas flowing through the exhaust pipe 3 (in this example, the second exhaust pipe 3b). ) to burn off the oxides. A large amount of SiOx, which is the cause of the oxide deposited in the exhaust pipe line 3 and evaporates from the surface of the silicon melt, is generated when the silicon raw material is melted at a higher temperature in the main chamber 2a. Therefore, it is effective to perform the combustion operation in the exhaust pipe 3 (in this example, the second exhaust pipe 3b) after the raw material melting process (step S103), and in the process after the liquid deposition process (step S104). It is desirable to carry out the In particular, it is desirable to carry out the combustion operation in the single crystal cooling step (step S106), so that even if some trouble occurs during the oxide combustion operation, the inside of the exhaust pipe 3 (in this example, the second exhaust pipe 3b) Even if SiOx backflows into the main chamber 2a from ), the growth of the single-crystal silicon ingot has already been completed, so dislocations will not occur in the grown single-crystal silicon ingot.

The effects of the single-crystal silicon ingot manufacturing equipment of this embodiment and the single-crystal silicon ingot manufacturing method of this embodiment will be described below.

The single-crystal silicon ingot manufacturing equipment 1 of this embodiment includes not only a first air supply unit 7 that is connected to a first exhaust pipe 3a and supplies air into the first exhaust pipe 3a, but also a second The second air supply section 9 is connected to the exhaust pipe 3b and supplies air into the second exhaust pipe 3b. According to this configuration, air can be supplied to each of the first exhaust pipe 3a and the second exhaust pipe 3b independently, and air can be supplied only to the second exhaust pipe 3b during lifting. . As a result, the oxides in the second exhaust pipe 3b can be burned during pulling by supplying air, as described in the embodiment of the method for manufacturing a single crystal silicon ingot, and the oxides being pulled can be burned. can prevent sudden combustion and sudden rise in pressure. Moreover, since the oxide combustion operation is performed during pulling, higher temperature Ar gas is generated in the second exhaust pipe 3b compared to the oxide combustion operation performed after the pulling is completed and the heater power is turned off. As a result, the combustion effect of the oxides is further enhanced, and the oxides deposited in the second exhaust pipe 3b on the side of the vacuum pump 4 can be sufficiently burned. Further, the second exhaust pipe 3b is provided with a pressure adjustment section 8 that adjusts the pressure inside the first exhaust pipe 3a, and the second air supply section 9 is connected to the rear side of the pressure adjustment section 8. By doing so, it is possible to eliminate pressure fluctuations in the first exhaust pipe 3a that occur when air is supplied into the second exhaust pipe 3b, and as a result, the pressure fluctuations caused by the backflow of exhaust gas into the main chamber 2a can be eliminated. Contamination can be avoided.

In addition, the method for manufacturing a single crystal silicon ingot of the present embodiment includes at least one of the liquid deposition process (step S104), the single crystal growth process (step S105), and the single crystal cooling process (step S106). , air is supplied (from the second air supply section 9 in this example) to the inert gas flowing inside the exhaust pipe 3 (in this example, inside the second exhaust pipe 3b), so that the inside of the exhaust pipe 3 ( In this example, the oxides in the second exhaust pipe 3b are burned. Thereby, the oxides in the exhaust pipe line 3 (in the second exhaust pipe 3b in this example) can be burned while being pulled up. Therefore, it is possible to prevent rapid combustion of oxides and a sudden increase in pressure during pulling of a single crystal silicon ingot, and it is possible to promote combustion of oxides deposited in the exhaust pipe. In addition, the pressure inside the first exhaust pipe 3a that occurs when air is supplied into the exhaust pipe line 3 (in this example, inside the second exhaust pipe 3b) is measured, and the pressure is determined based on the measured pressure fluctuation value. It is preferable that the pressure inside the first exhaust pipe 3a is adjusted by the adjustment unit 8, so that the above-mentioned air supply can be performed more safely.

In the method for manufacturing a single crystal silicon ingot according to the present embodiment, after the single crystal cooling step (step S106) of the single crystal silicon ingot, and before returning the inside of the chamber of the single crystal silicon ingot manufacturing apparatus 2 to normal pressure, the first The air supply section 7, or the first air supply section 7 and the second air supply section 9 supply air into the first exhaust pipe 3a, or the first exhaust pipe 3a and the second exhaust pipe 3b, respectively. It is preferable to further include supplying air (step S111) to combust the oxides in the first exhaust pipe 3a or the first exhaust pipe 3a and the second exhaust pipe 3b. Even after the pulling of one single crystal silicon ingot is completed, by burning the oxides in the first exhaust pipe 3a and the second exhaust pipe 3b, the oxides are further burned and the accumulation of oxides is effectively reduced. This is because it can be effectively reduced.
Furthermore, the method for manufacturing a single crystal silicon ingot according to the present embodiment includes a raw material melting process (step S103), a liquid deposition process (step S104), a single crystal growing process (step S105), and a single crystal cooling process (step S106). It is preferable to use a multi-pulling method in which multiple single-crystal silicon ingots are manufactured using the same quartz crucible by repeating the process. This is because the above effects can be advantageously obtained by promoting the combustion of substances.
Further, when manufacturing a plurality of single crystal silicon ingots, it is preferable to supply the above-mentioned air (from the second air supply unit 9 in this example) each time one single crystal silicon ingot is manufactured, As a result, the oxide is burned before a large amount of oxide is deposited inside the exhaust pipe line 3 (in this example, inside the second exhaust pipe 3b), and the oxide is burned during pulling of the single crystal silicon ingot. It can prevent sudden combustion and pressure rise.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Example 1)
In order to confirm the effects of the present invention, one single crystal silicon ingot was manufactured using the single crystal silicon ingot manufacturing equipment shown in Figure 1 for Invention Examples 1 to 3 and Figures 3 to 4 for Comparative Examples 1 to 2. We conducted an experiment to raise the . The conditions for pulling the single-crystal silicon ingot were the same in each example, and experiments were conducted in which the timing of air supply was varied. Thereafter, an oxide combustion evaluation test when the dust chamber was opened and an oxide forced ignition test were conducted.
Here, the "combustion evaluation test of oxides when the dust chamber is opened" refers to the combustion evaluation test of oxides collected in the dust chamber 11 by opening the lid of the dust chamber 11 6 hours after the completion of lifting. This is a test to confirm. In addition, the "forced ignition test" refers to collecting the oxides that were not burned in the "combustion evaluation test of oxides when the dust chamber is open" and evaluating the presence or absence of combustion when the oxides are forcibly ignited with a lighter, etc. It's a test.

In Comparative Example 1, air was not supplied into the exhaust pipe line 3. Specifically, after the growth of the single crystal silicon ingot was completed and the single crystal silicon ingot was moved from the main chamber 2a to the pull chamber 2b, the heater power was turned off. After turning off the heater power and 6 hours after the completion of lifting, an oxide combustion evaluation test was conducted when the lid of the dust chamber 11 was opened. As a result, when the lid of the dust chamber 11 was opened, the oxides collected in the dust chamber 11 were violently burned. Therefore, in Comparative Example 1, a forced ignition test was not conducted.

In Comparative Example 2, an experiment was conducted under the same conditions as Comparative Example 1, except that after the heater power was turned off, air was supplied from the air supply section to the exhaust pipe line 3 before returning the chamber to normal pressure. . As a result, no combustion reaction of oxides was observed when the lid of the dust chamber 11 was opened. Further, when the oxide was recovered from the dust chamber 11 and a forced ignition test was conducted, it was confirmed that the oxide combusts violently. That is, in Comparative Example 2, although the oxide combustion operation was carried out by supplying air, it was confirmed that the combustion effect of the oxides deposited in the exhaust pipe line 3 was low when air was supplied after the completion of pulling.

In Invention Example 1, air was supplied from the second air supply section 9 into the second exhaust pipe 3b during the liquid deposition process (step S104). As a result, when the lid of the dust chamber 11 was opened, no combustion reaction of oxides was observed. Further, when a forced ignition test was conducted on the oxides recovered from the dust chamber 11, a slight amount of combustion of the oxides was confirmed.
In addition, in Invention Example 1, even though the oxide combustion operation was performed by supplying air during the deposition process, no pressure fluctuation was observed in the main chamber 2a, and a dislocation-free single crystal silicon ingot was grown. I was able to do that.

In invention example 2, air was supplied from the second air supply section 9 into the second exhaust pipe 3b during the single crystal cooling process (step S106). No combustion of oxides was observed when the lid of the dust chamber 11 was opened, and a slight combustion of oxides was confirmed in the forced ignition test.

In invention example 3, air is supplied from the second air supply section 9 into the second exhaust pipe 3b during the single crystal cooling process (step S106), and before the inside of the chamber is returned to normal pressure, the first Air was supplied from the air supply section 7 and the second air supply section 9 into the first exhaust pipe 3a and the second exhaust pipe 3b, respectively (step S111). No combustion of the oxide was observed when the lid of the dust chamber 11 was opened, and no combustion was observed in the forced ignition test.

(Example 2)
In order to confirm the effect of the present invention in the multi-pulling method, two single crystal silicon ingots were produced using the single crystal silicon ingot manufacturing equipment shown in Figure 1 for Invention Examples 4 to 6 and Figure 4 for Comparative Example 3. We conducted a continuous raising experiment. An oxide ignition evaluation test when the dust chamber was opened and an oxide forced ignition test were conducted under the same conditions as in Example 1, except that pulling was carried out by the multi-pulling method.

In Comparative Example 3, after completing pulling of two single crystal silicon ingots by the multiple pulling method and turning off the heater power, air was supplied into the exhaust pipe line 3 from the first air supply section 7. Vigorous combustion of the oxide was observed when the lid of the dust chamber 11 was opened. For this reason, a forced ignition test was not conducted.

In Inventive Example 4, air was supplied from the second air supply section 9 into the second exhaust pipe 3b during the second single crystal cooling step of the multi-pulling method. No combustion of the oxide was observed when the dust chamber 11 was opened, and it was confirmed that the oxide burned slightly in the forced ignition test.

In Invention Example 5, air was supplied from the second air supply section into the second exhaust pipe 3b during the first and second single crystal cooling steps of the multiplexing method. As a result, similarly to Invention Example 4, no combustion of the oxide was observed when the dust chamber 11 was opened, and it was confirmed that the oxide was slightly burned in the forced ignition test.
When compared with Invention Example 4, it was confirmed that the amount of oxide burned during the evaluation test was small. This is because the amount of oxides deposited in the second exhaust pipe 3b was small because the oxides in the second exhaust pipe 3b were burned each time the single crystal cooling process was performed. It is assumed that.

In invention example 6, air is supplied from the second air supply section 9 into the second exhaust pipe 3b during the first and second single crystal cooling steps of the multiplexing method, and the inside of the chamber is brought to normal pressure. Before returning, air was supplied from the first and second air supply sections. However, air supply (step S111) was not performed during the first single crystal cooling step of the multiplexing method and after the heater power was turned off. The oxides did not burn when the dust chamber was opened and did not burn in forced ignition tests.

Table 1 summarizes the evaluation results for Invention Examples 1 to 6 and Comparative Examples 1 to 3 in Example 1 and Example 2.
In Invention Examples 1 to 3, when air is supplied to the second exhaust pipe 3b during pulling, the oxide combustion effect is higher than when air is supplied into the exhaust pipe 3 after the pulling is completed. This was confirmed.
Furthermore, when multiple single crystal silicon ingots are grown using the multi-pulling method, the amount of oxides deposited in the exhaust pipe 3 also increases, so it is expected that the oxides will not be able to burn sufficiently. As is clear from the results of Invention Examples 4 to 6, it was confirmed that when air was supplied into the second exhaust pipe during pulling, oxides could be sufficiently burned in the multiple pulling method.

1: Single crystal silicon ingot manufacturing equipment,
2: Single crystal silicon ingot manufacturing equipment,
3: Exhaust pipe line,
4: Vacuum pump,
5a: inert gas supply port,
5b, 5c: switch valve,
6: Exhaust gas port,
7: first air supply section,
8: Pressure adjustment section,
9: second air supply section,
10: Pressure gauge,
11: Dust chamber,
12: control unit,
13: Flapper valve (explosion proof valve),
14: Cyclone

Claims (9)

an exhaust pipe connected to a single crystal silicon ingot manufacturing device;
A single-crystal silicon ingot manufacturing facility, comprising: a vacuum pump that sucks inert gas supplied into the single-crystal silicon ingot manufacturing device through the exhaust pipe,
The exhaust pipe line includes a first exhaust pipe connected to an exhaust gas port of the single crystal silicon ingot manufacturing apparatus, and a second exhaust pipe connecting the first exhaust pipe and the vacuum pump. , consisting of;
a first air supply unit connected to the first exhaust pipe and supplying air into the first exhaust pipe;
A single-crystal silicon ingot manufacturing facility, comprising: a second air supply unit connected to the second exhaust pipe and supplying air into the second exhaust pipe. The second exhaust pipe is provided with a pressure adjustment part that adjusts the pressure inside the first exhaust pipe,
When the exhaust gas port side is the front side of the exhaust pipe and the vacuum pump side is the rear side of the exhaust pipe, the second air supply section is connected to the rear side of the pressure adjustment section. The single crystal silicon ingot manufacturing equipment according to claim 1. A method for producing a single crystal silicon ingot by the Czochralski method, the method comprising:
a raw material melting step of heating and melting silicon raw material filled in a quartz crucible;
a liquid deposition step of lowering a seed crystal to deposit it on the silicon melt in the quartz crucible;
a single crystal growth step of pulling a single crystal silicon ingot from the silicon melt in the quartz crucible;
A single crystal cooling step of cooling the grown single crystal silicon ingot,
In any one or more of the liquid deposition step, the single crystal growth step, and the single crystal cooling step, air is introduced into an inert gas flowing in an exhaust pipe connected to a manufacturing device for a single crystal silicon ingot. A method for producing a single-crystal silicon ingot, characterized in that the oxides in the exhaust pipe are burned by supplying the same. A method for manufacturing a single crystal silicon ingot according to claim 3 by the Czochralski method using the single crystal silicon ingot manufacturing equipment according to claim 1 or 2,
In any one or more of the liquid deposition step, the single crystal growth step, and the single crystal cooling step, air is supplied from the second air supply section to the inert gas flowing in the second exhaust pipe. and burning the oxide in the second exhaust pipe. A method for manufacturing a single crystal silicon ingot according to claim 4, using the single crystal silicon ingot manufacturing equipment according to claim 2,
The pressure inside the first exhaust pipe that occurs when air is supplied into the second exhaust pipe is measured, and the pressure inside the first exhaust pipe is adjusted by the pressure adjustment section based on the measured pressure fluctuation value. A method for producing a single crystal silicon ingot. A multi-pulling method in which a plurality of single-crystal silicon ingots are manufactured using the same quartz crucible by repeating the raw material melting process, the liquid deposition process, the single-crystal growth process, and the single-crystal cooling process. The method for producing a single crystal silicon ingot according to any one of claims 3 to 5, wherein the method comprises: When manufacturing a plurality of the single crystal silicon ingots, each time one of the single crystal silicon ingots is manufactured, air is supplied into the second exhaust pipe by the second air supply unit. 7. The method for manufacturing a single crystal silicon ingot according to claim 6, wherein the oxide in the second exhaust pipe is burned. After the single-crystal cooling process of the single-crystal silicon ingot and before returning the inside of the chamber of the single-crystal silicon ingot manufacturing apparatus to normal pressure, the first air supply section cools the inside of the first exhaust pipe. The method for producing a single crystal silicon ingot according to any one of claims 3 to 7, wherein air is supplied to burn the oxide in the first exhaust pipe. After the single-crystal cooling step of the single-crystal silicon ingot, before returning the inside of the chamber of the single-crystal silicon ingot manufacturing apparatus to normal pressure, the first air supply unit and the second air supply unit provide the Any one of claims 3 to 7, wherein air is supplied into the first exhaust pipe and the second exhaust pipe to burn the oxides in the first exhaust pipe and the second exhaust pipe. The method for producing a single crystal silicon ingot as described in 2.

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