JPH06247788A - Method for producing silicon single crystal and device therefor - Google Patents

Abstract

PURPOSE:To obtain a high-quality silicon single crystal by freely operating the slide opening and closing mechanism, etc., of the cooling cylinder arranged in a single crystal producing device. CONSTITUTION:A crucible 4 charged with polycrystal silicon is heated with a heater 5 to melt the raw material and to obtain a molten material 9, a seed crystal 12 is dipped in the molten material 9, the crucible 4 and seed crystal 12 are rotated and pulled up, and a single crystal ingot 10 is introduced into the space in the cylinder 22 provided on the inner periphery of a cooling cylinder 21. An inert gas is simultaneously introduced into a chamber 2 from an inert gas inlet 15 furnished on the wall surface of a pulling-up chamber 2b, passed through the gap between the inner periphery of the cooling cylinder 21, etc., and the ingot 10 and allowed to flow down into a heating chamber 2a. Meanwhile, an inert gas is introduced from an inlet 23 provided to the upper wall surface of the chamber 2, passed through an inert gas pipe 24 furnished outside the cooling cylinder 21, blown against the surface of the ingot 10 from an inert gas inlet 25 vertically to the axis of a single crystal, blown against the vicinity of the lower end of the ingot 10 and exhausted from an exhaust port 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method and an apparatus therefor capable of obtaining a high quality silicon single crystal.

[0002]

As a method for producing a single crystal, the Czochralski method (CZ method) for pulling a crystal from a melt in a crucible while growing the crystal is widely used.

In order to obtain a silicon single crystal by the CZ method, a single crystal manufacturing apparatus having a structure as schematically shown in FIG. 4 is used.

As shown in FIG. 4, the single crystal manufacturing apparatus 41 has a chamber 2 composed of a heating chamber section 2a and a pulling chamber section 2b. A driving device (not shown) located outside the chamber 2 in the heating chamber portion 2a.
A quartz crucible 4 supported by a rotary shaft 3 extending through the bottom of the chamber is disposed, and the crucible 4 is also provided.
Is provided with a cylindrical heater 5 surrounding the heater 5 at a predetermined interval, and a heat insulating material 6 is provided outside the heater 5.
Are arranged. In this example, the quartz crucible 4
The outer periphery of the graphite crucible 7 is protected by a graphite crucible 7, and the graphite crucible 7 is supported by the rotating shaft 4 via a graphite tray 8.

On the other hand, the pulling chamber portion 2b extends from the silicon melt 9 formed in the quartz crucible 4 above the heating chamber portion 2a along the pulling axis from the heating chamber portion 2a. Is also a part with a small inner diameter.

Further, a pulling wire 14 having a chuck 13 for holding the seed crystal 12 at a tip portion penetrating from the upper wall surface of the chamber and hanging from above is arranged in the chamber 2, and the pulling wire 14 is The wire pulling device 11 provided on the upper portion of the pulling chamber portion 2b enables the lifting and lowering while rotating.

Single crystal manufacturing apparatus 4 having such a configuration
In No. 1, in order to grow a single crystal, first, a predetermined amount of raw materials such as polycrystalline silicon and a dopant that is added as needed is charged in a quartz crucible 4 and heated by a heater 5 to melt the raw materials. To form a melt 9. Then, the seed crystal 12 attached to the tip of the pulling wire 14 is immersed in the melt 9 and pulled while rotating the quartz crucible 4 and the seed crystal 12 to grow the single crystal ingot 10 at the lower end of the seed crystal 12. Is.

By the way, in such a single crystal pulling method, a large amount of impurities such as oxygen are mixed in the melt 9 by the melting of the quartz crucible 4 and the grown silicon single crystal 10 is grown.
It is known that this impurity is taken in to cause point defects, and the point defects are nucleated and precipitated by the subsequent thermal history,
Forming defects such as oxygen induced stacking faults (OSFs) that have a significant impact on product quality has become a problem.

From the above viewpoint, the nucleation and precipitation of point defects in the single crystal is suppressed by improving the cooling rate of the single crystal during pulling and controlling the thermal history of the single crystal, and also producing In order to improve efficiency, it has been proposed to arrange a cylindrical heat shield surrounding the single crystal ingot 10 being pulled into the chamber 2 at regular intervals. For example, Japanese Unexamined Patent Publication No. 47-26388 discloses that a cylindrical body is provided that hangs from the upper wall surface of the heating chamber 2a and surrounds the growing silicon single crystal as an axis. It is known that the cooling rate of the single crystal being pulled is maximized at the lower end of the tubular body by installing the tubular body. In addition, such a cylindrical body and the single crystal ingot 10
In order to improve the heat exchange with
No. 05397 and Japanese Patent Laid-Open No. 61-68389 disclose a water-cooled tubular body. Further, in Japanese Patent Laid-Open No. 64-18988, a plurality of heat shield plates are required around the single crystal pulling portion in order to effectively shield the radiant heat from the melt and the radiant heat from the heater or crucible. It is disclosed that a space is provided. Further, in Japanese Patent Laid-Open No. 64-65086, a cylindrical body coaxially surrounding a silicon single crystal is provided in order to reduce the OSF and enhance the function of preventing the precipitation of SiO. One end of the cylindrical body has an opening at the center of the pulling chamber ceiling. There is disclosed a structure in which a collar is airtightly coupled, and the other end has a collar that hangs down toward the surface of the melt in the quartz crucible and folds back upward to expand. Japanese Patent Application Laid-Open No. 2-157180 discloses a cylindrical body for supplying an inert gas, which is vertically movable so as to secure a sufficiently large raw material charging space without impairing the original function of the cylindrical body. Has been done.

[0010]

However, even if a simple cylindrical body as described in Japanese Patent Laid-Open No. 47-26388 is arranged in the chamber, the heat shielding by this cylindrical body is not sufficient. However, the desired cooling effect was not obtained, the cooling rate was not sufficiently improved, and the thermal history of the single crystal could not be completely controlled. Further, JP-A-57-205397 and JP-A-61
As described in JP-A-68389, there is a problem in that the water cooling of the tubular body complicates the device configuration and the control mechanism and increases the cost. Further, JP-A 64-65
In the case of the shape of the lower end portion of the tubular body as described in Japanese Patent No. 086, since the shape is fixed, if an attempt is made to obtain an optimum cooling rate according to the manufacturing conditions, the optimum cooling rate is obtained every time the manufacturing conditions are changed. There is a problem that it is necessary to replace with a cylindrical body having a lower end portion shape that achieves a cooling rate, and workability and the structure of the replacement portion are complicated, resulting in high cost. Similarly, when providing a plurality of heat shield plates as described in JP-A-64-18988, since the heat shield plates are fixed, it is attempted to obtain an optimum cooling rate according to the manufacturing conditions. Since it is necessary to change the number, shape and interval of the heat shield plates that produce the optimum cooling rate every time the manufacturing conditions are changed, it takes a long time for the replacement work, and there are many component members, There was a problem that the cost increased due to the necessity of maintenance. Furthermore, when a simple cylindrical body as described in Japanese Patent Laid-Open No. 2-157180 is arranged in the chamber so as to be vertically movable, the effect of securing a sufficiently large raw material charging space to be solved by the present invention can be obtained. However, the heat shielding effect by the cylinder is not sufficient like the cylinder of JP-A-47-26388, and the desired cooling effect is not obtained, and the heat history of the single crystal is completely eliminated. It could not be controlled.

Further, in the cylindrical body disclosed above as the prior art, the cooling rate of the single crystal during pulling is improved and the thermal history of the single crystal is controlled to nucleate the point defects in the single crystal. In order to suppress precipitation and improve production efficiency, the temperature range that requires rapid cooling and the temperature range that requires slow cooling differ depending on the type of each single crystal. Accordingly, unless the cylindrical length or thickness is changed to achieve the desired effect, it is difficult to obtain the desired cooling effect, and the cooling rate can be adjusted according to the type of each single crystal with one type of cylindrical body. Nothing capable of performing a high degree thermal history control has been disclosed.

When a silicon single crystal is to be obtained by the CZ method, different control is required for each type of single crystal as described above, and the single crystal is grown even by growing the single crystal once. The pulling speed is different between the stage where the growth is completed and the stage where the growth is completed (in this stage, the pulling speed is increased to improve productivity). It is desired that the cooling rate can be adjusted according to each pulling rate in order to make the entire single crystal ingot have a more uniform thermal history, but to date such thermal history control with high degree of freedom can be performed. Is currently not disclosed at all.

Therefore, it is an object of the present invention to provide an improved method and apparatus for producing a silicon single crystal.

According to the present invention, the cooling rate of the single crystal is adjusted in accordance with the type of the single crystal and each pulling rate at the time of growing the single crystal once, and the thermal history control with a high degree of freedom is performed. An object of the present invention is to provide a method for producing a silicon single crystal and an apparatus for the same.

Another object of the present invention is to provide a method and apparatus for producing a high quality silicon single crystal by pulling a single crystal ingot with a high cooling rate.

The present invention further relates to SiO generated from the melt.
An object of the present invention is to provide a method and an apparatus for producing a silicon single crystal capable of efficiently cooling a single crystal ingot that is pulled while suppressing solidification and adhesion of gas.

[0017]

SUMMARY OF THE INVENTION The present inventors have
In order to achieve the above objects, as a result of diligent examination of a method and an apparatus for producing a silicon single crystal that pulls a silicon single crystal from a melt in a crucible installed in a chamber, concentric circles are formed around the growing single crystal. -Like cooling cylinder is provided above the crucible in the chamber, and a slide type opening / closing mechanism (structure) capable of opening and closing a part of the side surface of the cylinder of the cooling cylinder is used to prevent radiation heat and radiation heat from the outside. The sliding type opening / closing mechanism (structure) can be adjusted arbitrarily according to the opening degree of the sliding type opening / closing mechanism (structure), and the cooling cylinders can be connected in several stages as necessary to individually adjust the sliding type opening / closing mechanism (structure). The thermal history of the high, middle and low temperature parts of the crystal can be adjusted independently by changing the opening degree of the crystal, and if necessary, by providing an outlet for the inert gas in the cooling cylinder, (Temperature range that requires rapid cooling Minutes) to increase the cooling rate, and if necessary, by installing a quartz cylinder on at least one of the inner peripheral surface and the outer peripheral surface of the cooling cylinder, the slide type opening / closing mechanism (structure) It has been found that the flow of the inert gas can be rectified regardless of the opening of), and the present invention has been completed based on this finding.

That is, the object of the present invention is (1) in a method for producing a silicon single crystal in which a silicon single crystal is pulled from a melt in a crucible installed in a chamber, concentric circles are formed around the growing single crystal. Of the cooling cylinder is disposed above the crucible in the chamber, and a sliding type opening / closing mechanism is provided on the side surface of the cylindrical body of the cooling cylinder. The sliding amount is adjusted by the opening / closing mechanism and the cooling cylinder and the cooling cylinder are connected to each other. This can be achieved by a method for producing a silicon single crystal, which is characterized in that a single crystal pulling operation is performed while blowing an inert gas into a gap between the single crystal and the single crystal.

Another object of the present invention is (2) the above-mentioned (1), wherein the cooling cylinders are provided in a plurality of stages in the direction of the rotation axis of the single crystal, and each cooling cylinder has an independent opening / closing mechanism. It can also be achieved by a method for producing a silicon single crystal.

A further object of the present invention is (3) the silicon single crystal according to the above (1) or (2), wherein a quartz cylinder is provided on at least one of the inner peripheral surface and the outer peripheral surface of the cooling cylinder. It can also be achieved by a manufacturing method.

Still another object of the present invention is (4) an inert gas introducing port for passing an inert gas is provided on the wall surface of the chamber, and an inert gas pipe connected to the introducing port is provided on the outer surface of the cooling cylinder. The other end of the inert gas pipe is connected to the inert gas outlet provided in the cooling cylinder, and the single crystal pulling operation is performed while blowing the inert gas from the outlet, It can also be achieved by the method for producing a silicon single crystal according to any of (3).

Another object of the present invention is (5) the production of a silicon single crystal according to the above (4), wherein the flow rate of the inert gas blown from the inert gas outlet is independently controlled in each cooling cylinder. It can also be achieved by a method.

Another object of the present invention is (6) an apparatus for producing a silicon single crystal that pulls a silicon single crystal from a melt in a crucible installed in a chamber, wherein the surrounding of the growing single crystal. A concentric cooling cylinder is arranged above the crucible in the chamber, and a slide type opening / closing mechanism is provided on the side surface of the cylinder of the cooling cylinder, and an inert gas is blown into the gap between the cooling cylinder and the single crystal. This can be achieved by an apparatus for producing a silicon single crystal, which is characterized in that an inert gas introduction port that can be used is provided on the chamber wall surface.

Another object of the present invention is (7), wherein the cooling cylinders are provided in a plurality of stages in the direction of the rotation axis of the single crystal, and each cooling cylinder has an independent opening / closing mechanism. It can also be achieved by the apparatus for producing a silicon single crystal described in 1.

Still another object of the present invention is (8) the silicon unit described in (6) or (7) above, wherein a quartz cylinder is provided on at least one of the inner peripheral surface and the outer peripheral surface of the cooling cylinder. It can also be achieved by an apparatus for producing crystals.

Still another object of the present invention is (9) an inert gas inlet through which an inert gas is passed is provided on the wall surface of the chamber, and an inert gas pipe connected to the inlet is provided outside the cooling cylinder. The apparatus for producing a silicon single crystal according to any one of the above (6) to (8), wherein the apparatus is attached to a surface portion and the other end of the inert gas pipe is connected to an inert gas outlet provided in the cooling cylinder. Can also be achieved by.

Another object of the present invention is (10) the silicon according to the above (9), which has a mechanism for independently controlling the flow rate of the inert gas blown from the inert gas outlet in each cooling cylinder. It can also be achieved by an apparatus for producing a single crystal.

[0028]

In the present invention, when the single crystal ingot is pulled up, in order to effectively shield the radiant heat or radiant heat from the peripheral heat source, a concentric cooling tube is provided around the single crystal ingot in the chamber. Although it is arranged above the crucible, it is a sliding type opening / closing mechanism capable of opening and closing the side surface of the cooling cylinder, and the radiant heat from the heat source in the peripheral part and the amount of radiant heat are provided in the sliding type opening / closing mechanism (structure. It is possible to quantitatively (analog) change the amount of radiative heat transfer entering the crystal surface by arbitrarily adjusting it according to the openness of the body. In this case, since the crystal is rotating, even if the radiative heat transfer enters non-axisymmetrically, the amount of radiation to the crystal is averaged and made uniform.

Further, in the present invention, if necessary, a plurality of cooling cylinders having the slide type opening / closing mechanism (structure) are stacked in the rotational axis direction to radiate in accordance with each part of the single crystal. The amount of heat transfer can be changed,
Further, each cooling cylinder is provided with an inert gas outlet, and an inert gas pipe is arranged on the outer peripheral portion of the cooling cylinder so as to communicate with the outlet, and the inert gas is blown to the corresponding portion of the single crystal. It is possible to rapidly cool the nuclei of point defects when the temperature range that requires rapid cooling and the temperature range that requires slow cooling are different depending on the type of single crystal, or when the type of single crystal is changed. Even when the position corresponding to the temperature range that tends to occur fluctuates, the optimum cooling rate for each type of single crystal can be obtained when the single crystal ingot is manufactured.

Further, in the present invention, if necessary,
By providing a quartz cylindrical body on at least one of the inner peripheral surface and the outer peripheral surface of the cooling cylinder, the flow of the inert gas is disturbed when the slide type opening / closing mechanism (structure) of the cooling cylinder is opened. It is possible to prevent the inert gas from flowing out of the opening to reduce the flow rate of the inert gas at the lower end portion of the cylindrical portion, and to rectify the flow of the inert gas, thereby solidifying the SiO gas. It can be adjusted so that the risk of adhesion does not increase.

Hereinafter, the present invention will be described in more detail based on the embodiments.

FIG. 1 is a use state diagram schematically showing a configuration of an embodiment of a single crystal manufacturing apparatus used in the method for manufacturing a silicon single crystal of the present invention.

As shown in FIG. 1, a silicon single crystal manufacturing apparatus 1 according to the present invention has a first cooling cylinder 21a, a second cooling cylinder 21b, and a third cooling cylinder 21c above a crucible 4 in a chamber 2. Are provided so as to be connected in three stages in the direction of the rotation axis, and a quartz cylindrical body 22 is provided on the inner peripheral portion of the cooling cylinders 21a to 21c.
And the inert gas inlet port 15 is provided in the gap between the inner peripheral portion of the cooling cylinder 21 and the single crystal ingot 10 (in the case where the quartz cylindrical body 22 is provided in the inner peripheral portion of the cooling cylinder 21). Is used to blow an inert gas into the gap between the inner peripheral portion of the quartz cylindrical body 22 and the single crystal ingot 10.
Further, an inert gas introducing port 23 through which an inert gas is passed is also provided on the upper wall surface of the chamber 2, and an inert gas pipe 24 connected to the introducing port 23 is arranged on the outer peripheral portion of the cooling cylinder 21.
The other end of the inert gas pipe 24 is provided with a cooling cylinder 21 (or both of the cooling cylinder 21 and the quartz cylinder 22 when the quartz cylinder 22 is provided on the inner peripheral portion of the cooling cylinder 21). ) Is connected to an inert gas outlet 25 provided in communication with each other, whereby the inert gas can be blown to each part of the single crystal ingot 10, and other configurations are the same as those in FIG. The conventional silicon single crystal manufacturing apparatus 51 shown in FIG. In FIG. 1, the same members as those in the apparatus shown in FIG. 4 are designated by the same reference numerals.

The cooling cylinders 21a to 21c are concentric circular cylinders around the growing single crystal ingot 10 (more specifically, two slide members each having an arc cross section perpendicular to the axis to be described later are formed in the circumferential direction). Each of the cooling cylinders 21a to 21c is provided with a slide type opening / closing mechanism on its side surface. By sliding and opening the side surface of the cylindrical body, the amount of radiant heat or radiant heat from the heat source in the peripheral portion is arbitrarily adjusted according to the opening width (opening degree) to enter the crystal surface. It is possible to change the amount of radiant heat transfer quantitatively (analog). FIG. 2 is a sectional view taken along line AA of FIG. The slide type opening / closing mechanism will be described with reference to FIGS. 1 and 2.

As the above-mentioned slide type opening / closing mechanism, two slide members 26a, 26b having an arc-shaped cross section perpendicular to the axis are used.
The cooling cylinder 21 is configured by providing (three or more slide members can be used as needed) slidably in the circumferential direction, and tooth portions are formed on the outer circumference of one slide member 26a. (When using a plurality of slide members, it is possible to form teeth on the outer periphery of at least one slide member), and the pinion 28 meshed with the teeth 27 is installed outside the chamber 2. And a drive source 29 such as a motor, and the drive source 29 causes the slide member 26 to slide relatively through the pinion 28 so that an opening portion between the end portions of the slide members 26a and 26b is formed. It can be achieved by adjusting the width. Here, it is preferable that the slide type opening / closing mechanism is independently provided in each of the cooling cylinders 21a to 21c, and is separately connected to the drive source 29 so as to be controlled for each of the cooling cylinders 21a to 21c.
The slide type opening / closing mechanism is not limited to the above-described embodiment, and may be a slide type opening / closing mechanism that has been conventionally used. For example, sliding the slide member by moving a wire. It is also possible to use a wire system for moving or a linear motor system for sliding the slide member using magnetism.

The width of the opening (opening degree α °) is arbitrarily adjusted according to the amount of radiant heat or radiant heat from the heat source in the peripheral portion, and when a plurality of cooling cylinders 21 are used. , Is determined for each individual cooling cylinder 21,
It is not particularly limited and is usually 0 (closed state) to
It is in the range of 180 °.

Next, the slide member 26 of the cooling cylinder 21.
a and 26b are slid relative to each other, and the slide member 26,
FIG. 3 shows various aspects of the seam of the openings formed between the ends of 26b.

In FIG. 3a, the ends of both slide members 26a, 26b forming the opening are formed in parallel with each other, and in FIG. 3b, the ends of the slide members 26a, 26b are formed in parallel with each other. 3c, the ends of the slide members 26a, 26b are formed in mesh with each other in FIG. 3c, and the ends of the slide members 26a, 26b are modified in FIG. 3c. As an example, the zigzag mesh is formed. Needless to say, the form of the seam of the opening is not limited to the above-mentioned forms.

Further, in the above embodiment, the case where the cooling cylinders 21 are used by connecting them in three stages in the rotation axis direction is shown, but the number of the cooling cylinders 21 used is not particularly limited. There may be at least one, but preferably a plurality of single crystal ingots are arranged in the axial direction of the single crystal ingot 10 so that the amount of radiant heat transfer can be changed in the width of the opening of each cooling cylinder 21. It is desirable to be used by connecting to.

Further, in the above embodiment, the quartz cylindrical body 22 is provided on the inner peripheral portion of the cooling cylinder 21, but the quartz cylindrical body 22 is, if necessary, the inner peripheral portion of the cooling cylinder 21. Alternatively, it may be provided on at least one of the outer peripheral portions, and by providing the quartz cylindrical body 22, even when the cooling cylinder 21 is opened by the slide type opening / closing mechanism, the inert gas is introduced from the opening. It is also possible to keep the flow of the inert gas rectified without leaking the gas to the outside without reducing the flow rate of the inert gas. The quartz cylindrical body 22 is preferably transparent so that the amount of heat radiated from the opening can be transmitted to the single crystal ingot 10 without being shielded by the quartz cylindrical body 22. It is desirable that the value is low.

Furthermore, in the above embodiment, if necessary, the inert gas outlet 25 may be provided in the case where the cooling cylinder 21 (or the quartz cylinder 22 is provided in the inner peripheral portion of the cooling cylinder 21). Is the cooling cylinder 21 and the quartz cylinder 2
2), and more preferably, an opening / closing mechanism (not shown) such as a shutter may be provided at the outlet 25. The flow rate of the inert gas from the inert gas outlet 25 can be appropriately adjusted by the opening / closing mechanism.

Next, in the above-mentioned embodiment, the upper end of the first cooling cylinder 21a is connected to the upper wall surface of the heating chamber portion 2a and can be made to hang down from here. In such a form, The active gas inlet 23 can be provided on the upper wall surface of the heating chamber portion 2a. As another embodiment, the upper end of the first cooling cylinder 21a is connected to the inner wall surface of the pulling chamber portion 2b of the water-cooled chamber 2, and the cooling barrel 21a is coaxial with the pulling axis of the single crystal ingot 10. It can be arranged so that it hangs from here. In this case, the outer diameter of the cooling cylinder 21 needs to be smaller than the inner diameter of the pulling chamber portion 2b, and further, it is necessary not to interfere with the installation position of the inert gas introduction port 15.

Since the length of the cylindrical body of the cooling cylinder 21 depends on the shape of the chamber 2 and the temperature range of the single crystal ingot 10 that actively cools, it is generally determined. However, it is necessary to be located at least below the installation position of the inert gas introduction port 15 provided on the upper wall surface of the heating chamber portion 2b when the heating chamber portion 2b is arranged in the chamber 2. When the upper end of the cooling cylinder 21a is connected to the inner wall surface of the pulling chamber part 2b, the length of the cylindrical body part in the heating chamber part 2b is about 50 to 200 mm. In addition, the third cooling cylinder 21c
Melt 9 whose lower end is formed in the quartz crucible 4
It can be located at a height of about 20 to 300 mm above the interface. When the lower end of the cooling cylinder 21c is lower than 20 mm from the interface of the silicon melt 9, the inert gas flowing down through the cooling cylinder 21c causes the silicon melt 9 near the growth interface of the single crystal ingot 10. Since it is directly blown onto the substrate and is cooled too much, thermal strain at the growth interface may induce dislocation of the single crystal ingot 10. On the contrary, when the lower end of the cooling cylinder 21c exceeds the height of 300 mm from the interface of the silicon melt 9, the cooling cylinder 2
1c is not preferable because the original cooling effect cannot be obtained sufficiently.

Incidentally, the above-mentioned conditions had to be changed according to the kind, diameter and length of the single crystal ingot to be grown, the melt temperature, the pulling rate, etc. in the prior art. When the silicon single crystal manufacturing apparatus is used, the above conditions are satisfied by freely adjusting the slide type opening / closing mechanism and the like provided in the cooling cylinder 21.
By forming the types of cooling cylinders 21, it becomes possible to deal with the types, diameters and lengths, melt temperatures, pulling rates, etc. of all single crystal ingots to be grown.

The inner diameter of the cooling cylinder 21 is the diameter of the single crystal ingot 10 to be pulled up (or the above-mentioned quartz cylinder 22).
Is provided in the inner peripheral portion of the cooling cylinder 21, the diameter is slightly larger than the diameter of the quartz cylinder 22),
The single crystal ingot 10 is formed concentrically around the single crystal ingot with a predetermined interval. The outer peripheral surface of the single crystal ingot 10 and the inner peripheral surface of the cooling cylinder 21 or the quartz cylindrical body 2 described above.
When 2 is provided in the inner peripheral portion of the cooling cylinder 21, the interval between the inner peripheral surface of the quartz cylindrical body 22 (hereinafter also simply referred to as the inner peripheral surface of the cooling cylinder 21) is about 10 Approximately 30 mm. The outer peripheral surface of the single crystal ingot 10 and the cooling cylinder 21
When the distance from the inner peripheral surface of the is less than 10 mm, when trying to flow a sufficient flow rate of the inert gas, the flow velocity becomes extremely high, and it becomes necessary to pressurize when introducing the inert gas, and the cooling cylinder It becomes difficult to form turbulence at the lower end of 21,
It becomes difficult to adjust the cooling rate. Further, when the distance between the outer peripheral surface of the single crystal ingot 10 and the inner peripheral surface of the cooling cylinder 21 changes, the cooling efficiency of the single crystal ingot 10 may change significantly, which may adversely affect the quality. . On the contrary, when the distance between the outer peripheral surface of the single crystal ingot 10 and the inner peripheral surface of the cooling cylinder 21 exceeds 30 mm, sufficient Si is obtained.
It is not preferable because the O exclusion efficiency cannot be obtained. Incidentally, in the past, the type and diameter of the single crystal ingot, the melt temperature, the pulling speed, was influenced by the pulling conditions such as the ingot length, it could not be specified unconditionally, the silicon single crystal manufacturing apparatus of the present invention In the case of using the cooling cylinder 21, one type of cooling cylinder 21 satisfying the above conditions is freely adjusted by adjusting a slide type opening / closing mechanism or the like provided in the cooling cylinder 21.
By forming, it becomes possible to deal with all kinds of single crystal ingots to be grown, diameter and length, melt temperature, pulling rate, and the like.

Titanium, molybdenum, carbon and the like are used as the material forming the cooling cylinder 21 according to the present invention, of which carbon and the like are particularly preferable. Further, when the cooling cylinder 21 is made of the above-mentioned metal, it is desirable that a part or all of the surface thereof is coated with glass or the like in order to prevent metal contamination of the silicon single crystal. The cooling cylinder 21 can be made of different materials in the radial direction of the cooling cylinder 21, and the slide members 26a and 26b described above can be used.
It is also possible to use different materials for each.

Further, in the embodiment shown in FIG. 1, as described above, the inert gas introducing port 15 is provided on the upper wall surface of the heating chamber 2a, and the inert gas introduced from here is introduced into the cooling cylinder 21. Circumferential surface and single crystal ingot 10
However, as long as the inert gas can be blown into the gap, the position, the configuration, etc. of the introduction portion are not particularly limited.

In order to pull up a silicon single crystal by using such a single crystal manufacturing apparatus 1, polycrystalline silicon and a dopant added as necessary in the quartz crucible 4 are prepared according to a conventional method. A predetermined amount of raw material is loaded and heated by the heater 5 to melt the raw material to form a melt 9.
Then, the seed crystal 12 attached to the tip of the pulling wire 14 is immersed in the melt 9 to form the quartz crucible 4 and the seed crystal 12.
Is pulled while rotating, and the single crystal ingot 10 is grown on the lower end of the seed crystal 12.

At this time, an inert gas such as argon gas is caused to flow into the chamber 2 through the inert gas inlet 15 provided on the wall surface of the pulling chamber 2b, and the inner peripheral surface of the cooling cylinder 21 is pulled from the pulling chamber 2b. Etc. and single crystal ingot 10
A gas flow is formed which flows through the gap between and into the heating chamber 2a. On the other hand, an inert gas is introduced from an inert gas inlet 23 provided on the upper wall surface of the chamber 2a into a portion that needs to be rapidly cooled if necessary, and is passed through an inert gas pipe 24 attached to the outside of the cooling cylinder 21. A gas flow blown out perpendicularly to the single crystal axis direction is formed on the surface of the single crystal ingot 10 through an inert gas outlet 25 provided in the cooling cylinder 21. These gas streams join together in the downstream region of the inert gas outlet 25, become a turbulent flow, and are blown to the vicinity of the lower end of the single crystal ingot 10, and then the exhaust port provided at the bottom of the heating chamber 2a. By sucking from an exhaust device (not shown) communicating with 16, it is discharged or collected outside the system and reused (including use by heat exchange).

Here, the flow rate of the gas flowing from the inert gas inlet port 15 through the gap between the inner peripheral surface of the cooling cylinder 21 and the single crystal ingot 10 is 10 to 200 liters / mi.
n, preferably 20 to 150 liters / min, more preferably 100 to 150 liters / min, and the inert gas outlet port 2 through the inert gas inlet port 23.
5, the flow rate of the gas blown onto the surface of the single crystal ingot 10 is 10 to 200 liter / min, preferably 50 to 150 liter / min, and more preferably 100.
~ 150 liters / min. Further, the gas flow rate from the inert gas inlet 15 and the inert gas inlet 2
The flow rate ratio to the gas flow rate from 3 is not particularly limited as long as it is within the range of each flow rate shown above, but 1: 1 to
It is desirable to introduce it at 1: 5 in order to increase the cooling rate.

Next, the single crystal ingot 10 is pulled up into the internal space of the cooling cylinder 21 as the growth progresses. In the method for producing a silicon single crystal of the present invention, the quartz cylindrical body 22 is cooled by the cooling cylinder. By providing the inner peripheral portion of the cooling pipe 21, even if the cooling pipe 21 is opened by the slide type opening / closing mechanism, the inert gas outlet port 2 of the cooling pipe 21 is provided.
In the downstream region of No. 5, since the inert gas is sufficiently blown, the cooling efficiency can be increased. Therefore, the temperature range in which the nucleus growth of the point defects taken in the single crystal ingot 10 easily occurs, for example, 1250 to By providing the inert gas outlet 25 at a position corresponding to the temperature range of 800 ° C., the cooling rate in the temperature range can be maximized, and the nucleus growth can be made difficult to occur. Below the gas outlet 25, the flow velocity of the inert gas is large and becomes turbulent, so that the possibility that SiO gas solidifies and adheres to the wall surface of the cooling cylinder 21 is small, and the free rate of silicon single crystal production is extremely high. Thus, a high quality silicon single crystal ingot can be easily obtained. Further, even when the temperature range changes depending on the type of single crystal, rapid cooling can be performed by appropriately adjusting the flow rates from the plurality of inert gas outlets 25 as described above, in addition to the above. Further, the thermal history of the single crystal can be controlled by further providing a plurality of cooling cylinders 21 and appropriately adjusting the opening degree by the above-mentioned stide type opening / closing mechanism.

[0052]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Using a single crystal production apparatus 1 as shown in FIG. 1, a diameter of about 1
The 55 mm n-type silicon single crystal ingot 10 was pulled up.

The cooling cylinder 21 is formed by using carbon as a material, and the inside diameter of the cooling cylinder 21 is 180 mm.
One having a length of 150 mm is connected in three stages, the upper end of the first cooling cylinder 21a is connected and fixed to the upper wall surface of the heating chamber portion 2a, and the lower end of the third cooling cylinder 21c and the melt 9 It was installed so that the distance from the interface was 30 mm.

The sliding type opening / closing mechanism of the cooling cylinder 21 has the structure shown in FIGS. 1 and 2, and the pulling speed is 1 when the single crystal ingot 10 is grown.
When mm / min, the opening degree α of the first cooling cylinder 21a is 30 °, the opening degree α of the second cooling cylinder 21b is 0 °, and the opening degree α of the third cooling cylinder 21c is 30 °. Then, when the pulling speed increases to 5 mm / min after the growth of the single crystal ingot 10 is completed, the opening degree α of the first cooling cylinder 21a is 0 °, and the second cooling cylinder 21b is The opening degree α of was set to 0 ° and the opening degree α of the third cooling cylinder 21c was set to 0 °.

Also, the slide member 26b of the cooling cylinder 21
The quartz cylindrical body 22 was arranged so as to be inscribed in the. The length of the cylindrical body 22 is the same as that of the cooling cylinder 21.
2 having a thickness of about 2 mm was used (the distance between the outer peripheral surface of the single crystal ingot 10 and the inner peripheral surface of the cylindrical body 22 was 10.5 mm).

Further, an inert gas introducing port 23 is provided on the upper wall surface of the heating chamber portion 2a, and an inert gas pipe 24 connected to the introducing port 23 is provided in each of the cooling cylinders 21a to 21c.
And the other end of the inert gas pipe 24 is provided in three places of the cooling cylinders 21a to 21c (and the quartz cylinder 22 inscribed in the cooling cylinder 21). Those connected to the outlets 25 were used. Here, the inert gas outlet 25 is installed at a position corresponding to a temperature range of 1250 to 800 ° C. where the nucleus growth of point defects is likely to occur, and in the first cooling cylinder 21a, 30 mm below the upper end. In the second cooling cylinder 21b, the outlet 25 is provided 30 mm below the upper end and in the third cooling cylinder 21c 30 mm below the upper end, respectively, and a shutter is provided as an opening / closing mechanism (not shown). used.

Next, during the pulling operation, the gas flow rate flowing down from the inert gas inlet port 15 through the gap between the inner peripheral surface of the cooling cylinder 21 and the single crystal ingot 10 is 70 liter / min, and 3 through the active gas inlet 23
Single crystal ingot 10 through inert gas outlet 25
When the single crystal ingot 10 is grown, the total gas flow rate blown to the surface of the is 100 liter / m 2.
200 liters / in after the growth of the single crystal ingot 10 is completed and more rapid cooling is required.
Argon gas was blown in as min.

The OSF densities at three locations near the upper portion, the central portion and the lower portion of the silicon single crystal having a total length of 800 mm obtained by the pulling operation were evaluated. In addition, the evaluation of the OSF density was carried out by measuring the silicon wafers from three locations cut out from the single crystal ingot at 1000 ° C. for 16 hours.
After thermal oxidation for a period of time, etching was carried out and observation was carried out by observing with a microscope. The obtained minute defect densities were all less than 5 co / cm ² , and no difference in OSF density due to changes in the pulling rate during growth was observed.

Example 2 Using a single crystal manufacturing apparatus 1 as shown in FIG. 1, a diameter of about 2
A 10 mm n-type silicon single crystal ingot 10 was pulled up.

Here, the same cooling cylinder 21 as that used in Example 1 is used, and when the pulling speed is 1 mm / min while growing the single crystal ingot 10, the opening of the first cooling cylinder 21a is opened. The degree α is set to 10 °, the opening degree α of the second cooling cylinder 21b is set to 0 °, and the opening degree α of the third cooling cylinder 21c is set to 20 °. Is 5 mm / min, the opening degree α of the first cooling cylinder 21a is 0 °, the opening degree α of the second cooling cylinder 21b is 0 °, and the opening degree of the third cooling cylinder 21c is large. The degree α was set to 0 °.

The same quartz cylinder 22 as in Example 1 was used.

Further, the inert gas inlet 23, the inert gas pipe 24 and the inert gas outlet 25 are also used in the first embodiment.
The same one was used.

Next, during the pulling operation, the flow rate of the gas flowing from the inert gas inlet 15 through the gap between the inner peripheral surface of the cooling cylinder 21 and the single crystal ingot 10 is 100.
L / min, and single crystal ingot 1 from three inert gas outlets 25 through the inert gas inlet 23
The total gas flow rate blown to the surface of 0 is 0 liter / mi when the single crystal ingot 10 is grown.
n (not blown), and after the growth of the single crystal ingot 10 is completed, more rapid cooling is required, so 200
Argon gas was blown at a rate of 1 / min.

The OSF densities at three locations near the upper portion, the central portion and the lower portion of a silicon single crystal having a total length of 600 mm obtained by the pulling operation were evaluated. In addition, the evaluation of the OSF density was carried out by measuring the silicon wafers from three locations cut out from the single crystal ingot at 1000 ° C. for 16 hours.
After thermal oxidation for a period of time, etching was carried out and observation was carried out by observing with a microscope. The obtained fine defect densities were all 10 co / cm ² or less, and no difference in OSF density due to changes in pulling rate during growth was observed.

As is clear from the above results, Example 1
The quality of the silicon single crystal obtained in 1 to 2 is arranged in the single crystal manufacturing apparatus according to the present invention even when the type, diameter and length of the single crystal ingot to be grown, melt temperature, pulling rate, etc. are different. It was confirmed that this can be easily coped with by freely operating the sliding type opening / closing mechanism of the cooling cylinder, etc., and that the heat history can be freely controlled to be uniform over the entire length of the single crystal ingot.

[0067]

As described above, according to the present invention, by freely operating the sliding type opening / closing mechanism of the cooling cylinder arranged inside the single crystal manufacturing apparatus, the cooling cylinder of one kind can be used. The thermal history of the crystal can be controlled freely,
Optimal heat history can be given to different types of single crystal ingots, diameters and lengths, melt temperatures, pulling rates, and the like.

By performing the single crystal pulling operation while blowing the inert gas, the single crystal ingot during the pulling can be effectively and rapidly cooled, and the nucleation of point defects can be suppressed to a low level. It is possible to obtain a high quality single crystal ingot, and a quartz cylinder that can be provided as necessary may cause solidification and adhesion of SiO gas to a cooling cylinder arranged inside the single crystal manufacturing apparatus. Since it is also small, the free rate of the single crystal pulling operation is also improved.

[Brief description of drawings]

FIG. 1 is a use state diagram schematically showing a configuration of an embodiment of a manufacturing apparatus used in a method for manufacturing a silicon single crystal of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a schematic view of a mode in which a slide member of a cooling cylinder of a manufacturing apparatus used in the method for manufacturing a silicon single crystal of the present invention is slid relative to each other, and an opening formed between end portions of the slide member is joined. FIG.

FIG. 4 is a use state diagram schematically showing a configuration of a conventional silicon single crystal manufacturing apparatus.

[Explanation of symbols]

1, 41 ... Silicon single crystal manufacturing apparatus 2 ... Chamber 2a ... Heating chamber section 2b ... Pulling chamber section 3 ... Rotating shaft 4 ... Quartz crucible 5 ... Heating heater 6 ... Thermal insulation material 7 ... Graphite crucible 8 ... Graphite saucer 9 ... Silicon melt 10 ... Single crystal ingot 11 ... Wire pulling device 12 ... Seed crystal 13 ... Chuck 14 ... Pulling wire 15 ... Inert gas introduction port 16 ... Gas exhaust port 21 ... Cooling cylinder 22 ... Quartz cylinder 23 ... No Active gas inlet 24 ... Inert gas pipe 25 ... Inert gas outlet 26 ... Slide member 27 ... Tooth portion 28 ... Pinion 29 ... Drive source

Claims (10)

[Claims] 1. A method for producing a silicon single crystal in which a silicon single crystal is pulled from a melt in a crucible installed in a chamber, in which a concentric cooling cylinder is provided around the growing single crystal above the crucible in the chamber. The cooling cylinder is provided with a slide type opening / closing mechanism on the side surface of the cylinder. The sliding amount is adjusted by the opening / closing mechanism, and an inert gas is provided in the gap between the cooling cylinder and the single crystal. A method for producing a silicon single crystal, wherein a single crystal pulling operation is performed while blowing air. 2. The method for producing a silicon single crystal according to claim 1, wherein the cooling cylinders are provided in a plurality of stages in the rotation axis direction of the single crystal, and each of the cooling cylinders has an independent opening / closing mechanism. 3. The method for producing a silicon single crystal according to claim 1, wherein a quartz cylinder is provided on at least one of an inner peripheral portion and an outer peripheral portion of the cooling cylinder. 4. An inert gas pipe is provided on the wall surface of the chamber, the inert gas introducing port passing through the inert gas, and an inert gas pipe connected to the introducing port is arranged on an outer surface portion of the cooling cylinder. 4. The silicon according to claim 1, wherein the other end of the single crystal is connected to an inert gas outlet provided in the cooling cylinder, and the single crystal pulling operation is performed while blowing the inert gas from the outlet. Method for producing single crystal. 5. The cooling cylinder independently controls the flow rate of the inert gas blown from the inert gas outlet.
The method for producing a silicon single crystal according to 1. 6. A silicon single crystal manufacturing apparatus for pulling a silicon single crystal from a melt in a crucible installed in a chamber, wherein a cooling cylinder is concentrically formed around the growing single crystal in the chamber. Is provided above the crucible, a slide type opening / closing mechanism is provided on the side surface of the cooling cylinder, and an inert gas inlet capable of blowing an inert gas into the gap between the cooling cylinder and the single crystal is provided. An apparatus for producing a silicon single crystal, which is provided on a wall surface of a chamber. 7. The apparatus for producing a silicon single crystal according to claim 6, wherein the cooling cylinders are provided in a plurality of stages in the rotation axis direction of the single crystal, and each of the cooling cylinders has an independent opening / closing mechanism. 8. The apparatus for producing a silicon single crystal according to claim 6, wherein a quartz cylinder is provided on at least one of an inner peripheral surface and an outer peripheral surface of the cooling cylinder. 9. An inert gas inlet for passing an inert gas is provided on a wall surface of the chamber, and an inert gas pipe connected to the inlet is attached to an outer surface portion of the cooling cylinder, 9. The apparatus for producing a silicon single crystal according to claim 6, wherein the other end is connected to an inert gas outlet provided in the cooling cylinder. 10. The apparatus for producing a silicon single crystal according to claim 9, further comprising a mechanism for independently controlling a flow rate of the inert gas blown from the inert gas outlet in each cooling cylinder.