KR101901874B1 - Method for filling raw material, and method for preparaing single crystal - Google Patents

Abstract

An object of the present invention is to provide a method capable of suppressing height unevenness of an input raw material into a quartz crucible at the time of producing a single crystal.
In the step of filling the raw material in the quartz crucible, the raw material is accommodated in a rechargeable tube having a cylindrical member made of quartz for containing the raw material and a conical valve for opening and closing the lower end opening of the cylindrical member , A recharge tube containing the raw material is set in the chamber, the opening of the cylindrical member is opened in the conical valve, and the raw material contained in the recharge tube is charged into the quartz crucible, A raw material charging method, characterized in that the raw material is charged using the above-mentioned recharge tube having different cone angles of the conical valve at least one time during charging of the raw material during the above-mentioned two or more times of charging the raw material to be.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material charging method and a manufacturing method of a single crystal,

The present invention relates to a method for filling a raw material in a quartz crucible by using a recharge tube in the production of a single crystal.

As a method of manufacturing a silicon single crystal used as a substrate of a semiconductor integrated circuit, a CZ (Czochralski) method or a MCZ (magnetic field applied Czochralski) method of applying a magnetic field is generally used. In such a CZ / MCZ method, a silicon raw material is filled in a quartz crucible and melted, a seed crystal is added to the melt, and then the silicon single crystal can be grown by pulling up. In the single crystal manufacturing apparatus (impression apparatus) of the CZ / MCZ method, a heater for heating the melt is installed in a main chamber, and a quartz crucible for accommodating the melt is installed inside the heater.

Generally, first, a raw material is put into the quartz crucible and the raw material is melted by heating the heater. Depending on the recent large diameter of the silicon single crystal or the elongation of the crystal, only the raw material powder initially put in the quartz crucible is not enough, and the raw material may be further added. This is referred to as an additional charge, and the raw material is put into a recharge tube having a cone cone (conical valve) at the lower end in the same manner as the recharge described later, and the raw material is charged into the quartz crucible in the recharge tube . After the raw materials are completely melted, the growth of the silicon single crystal is started.

The quartz crucible is filled with the melt in which the raw material is dissolved, and the silicon single crystal is grown therefrom. The grown single crystal is accommodated and cooled in a pull-up chamber connected to the top of the main chamber through a gate valve. Then, the single crystal is taken out from the pulling chamber.

In this manufacturing, if one single crystal is grown from one quartz crucible, the growth is terminated at this point, but the quartz crucible is split and can not be reused, resulting in a high manufacturing cost. Thus, there is a case where multiple operations for growing a plurality of single crystals from one quartz crucible are performed. In this case, after the single crystal growth, the melt in the quartz crucible is reduced by the amount of the grown crystal, so that the following single crystal can not be grown as it is. Therefore, a recharging is performed in which the raw material is added again to compensate for this decrease.

As a recharging method, there have been long been proposed a method of loading by a load, a method of supplying from a raw material tank as disclosed in Patent Document 1, and the like. However, a technique which is dealt with in many patent documents is a method in which a raw material is received in a recharge tube having a conical valve at the lower end thereof, and the raw material accommodated in the recharge tube is charged into a quartz crucible. Patent Documents 2 and 3 disclose the basis of this technique. For example, in Patent Document 3, the conical angle (vertex angle) of the conical valve is described as 40 to 100 degrees, more preferably 60 to 90 degrees.

Using this method, a silicon single crystal was taken out from a pulling chamber separated by a gate valve, and then a recharge tube containing the raw material was mounted by hanging with a wire. The vacuum pressure in the pulling chamber was adjusted to the inside pressure in the main chamber Then, the gate valve is opened and the raw material is supplied.

For example, Patent Document 4 teaches improvement in covering a wire with a protective pipe, and Patent Document 5 teaches improvement of sealing a wire in a recharge tube or a conical valve for preventing breakage. In Patent Document 6, Discloses a technique of adding a groove to a conical valve for the sake of convenience. However, the basic technology is disclosed in Patent Documents 2 and 3.

As can be seen from this many documents, the recharge method using the recharge tube is one of the widely used technologies. However, since Patent Document 3, there has been no addition to the angle of the conical valve.

The raw materials to be charged as described above are generally polycrystalline or rarely single crystals, and those obtained by crushing such crystals are used, and there are pores in a state filled with the recharge tube. Therefore, in order to add a raw material corresponding to the portion in which the single crystal is grown, it is insufficient to feed the single crystal by one time using a return pipe. Therefore, a plurality of injections are continuously performed.

Japanese Patent Application Laid-Open No. 62-260791 Japanese Unexamined Patent Application Publication No. 2-157180 WO2002 / 068732 Patent Publication 2006-89294 Patent Publication No. 2008-13376 Patent Publication No. 2008-88000

In the case where the feedstock is continuously fed a plurality of times as described above, the conventional method uses the same type of the rechargeable tube, and the angle of the conical valve is constant, so that the raw material is concentratedly discharged at the same position when viewed in the radial direction. Therefore, the additional charged raw material is piled up in a donut shape in the quartz crucible, and the unevenness in the height of the unused raw material becomes large. Therefore, even if all of the raw materials are injected well after waiting for some time until the raw material is melted to some extent, it takes a long time to melt the raw material, and in any case, it takes a long time to melt the additional raw material there was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method capable of suppressing unevenness in height of a feedstock into a quartz crucible in the production of a single crystal.

In order to achieve the above object, the present invention provides a process for producing a single crystal having a step of filling a raw material in a quartz crucible, a step of melting the raw material in the quartz crucible to form a molten liquid, and a step of pulling a single crystal from the melt In the step of filling the raw material in the quartz crucible, the raw material is housed in a rechargeable tube having a cylindrical member made of quartz for containing the raw material and a conical valve for opening and closing the lower end opening of the cylindrical member, A raw material charging method in which raw materials charged in the quartz crucible are charged into the inside of the quartz crucible by opening the opening of the cylindrical member in the conical valve; Wherein at least one of the at least one source In charging, there is provided a method of filling a raw material characterized in that the cone angle of the conical valve charging the raw material using different Recharge the tube.

By using the conical valve having different cone angles as described above, it is possible to feed the raw material to a position different from the input position of the raw material in the case of filling other raw materials, and even if the raw material is continuously charged, the height of the input raw material into the quartz crucible It is possible to suppress unevenness. Therefore, the raw material filling and melting can be performed efficiently, and the productivity of production of a single crystal can be improved.

At this time, the cone angle of the conical valve is preferably in the range of 30 to 150 degrees.

In the case of such a conical angle, the raw material can be injected smoothly without reducing the capacity of the rechargeable tube, and the raw material charging can be performed more efficiently.

At this time, it is preferable to fill the raw material by using the above-mentioned recharge tube having the conical angle of the conical valve differing by 15 degrees or more in the at least one raw material filling.

By setting the conical angle to be different by 15 degrees or more, it is possible to effectively change the position where the raw material is put into the quartz crucible, and the height unevenness of the raw material can be reliably suppressed.

At this time, it is preferable that the diameter of the quartz crucible is 610 mm or more.

In such a large-diameter quartz crucible, there is a high need for suppressing the height unevenness of the raw material according to the present invention and more effectively works to improve the productivity of production of single crystals.

The present invention also provides a method of manufacturing a quartz crucible, comprising the steps of filling a raw material in a quartz crucible, a step of melting the raw material in the quartz crucible to make a melt, and a step of pulling up the single crystal from the melt, In the step of filling the raw material in the first pulling-up of the single crystal and / or the step of filling the raw material in the pulling-up of each of the second and subsequent single crystals, And filling the raw material by a charging method.

By using the raw material charging method of the present invention for the additional charge or the recharge in the production of the single crystal by the multi-pooling, the raw material charging and melting can be efficiently performed and the productivity of the single crystal can be improved .

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to efficiently fill and melt a raw material in a quartz crucible, and to improve the productivity of production of a single crystal.

1 is a schematic view showing an example of a single crystal manufacturing apparatus that can be used in the present invention.
2 is a schematic view showing an example of a recharge tube which can be used in the present invention.
Fig. 3 is a schematic view of a case where a raw material is filled in a quartz crucible by a recharge tube.
4 is a schematic view showing an example of a conical valve that can be used in the present invention.
FIG. 5 is a graph and a schematic diagram showing the distribution of the input material by the cone angle of the conical valve required in the experiment. FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings as an example of the embodiment, but the present invention is not limited thereto.

Fig. 1 is a CZ method single crystal manufacturing apparatus usable in the raw material filling method of the present invention.

1 includes a main chamber 1, a quartz crucible 6 and a graphite crucible 7 that accommodate the melt 5 in the main chamber 1, a quartz crucible 6, A heater 8 disposed around the graphite crucible 7 and a heat insulating member 9 around the outside of the heater 8 are connected to the upper portion of the main chamber 1 via the gate valve 3, (Single crystal ingot) 4, and a gas rectifying cylinder 12 surrounding the single crystal 4 during pulling-up. The impression chamber 2 is provided with a gas inlet 11 for introducing a gas circulating in the furnace and a gas outlet 10 for discharging the gas circulating in the furnace is installed at the bottom of the main chamber 1 . Further, a heat shield member 13 for cutting off heat radiation from the heater 8 and the melt 5 may also be provided. The quartz crucible 6 and the graphite crucible 7 can be lifted and lowered in the direction of the crystal growth axis and the quartz crucible 6 and the graphite crucible 7 are filled in the crucible 6 and the graphite crucible 7 so as to compensate for the decreased liquid level of the melt 5, . Thereby, the height of the liquid level of the melt 5 is kept substantially constant.

A magnetic field generator (not shown) is provided outside the main chamber 1 according to the manufacturing conditions and a magnetic field in a horizontal direction or a vertical direction is applied to the melt 5, So that the stable growth of the single crystal 4 can be achieved.

2, a quartz-made cylindrical member 15 for accommodating a raw material (polycrystal or single crystal) 14 and a cylindrical member 15 for holding the raw material (polycrystal or single crystal) The raw material 14 is accommodated in the recharge tube 17 having the conical valve 16 for opening and closing the opening at the lower end of the pulling chamber 2 and the reductant tube 17 containing the raw material 14 is held in the pulling chamber 2, And the opening of the cylindrical member 15 in the conical valve 16 is opened so that the raw material 14 accommodated in the return pipe 17 is introduced into the quartz crucible 6 ) Of the raw material. In the present invention, this raw material charging is carried out two or more times in succession before the single crystal growth.

In the present invention, the raw material 14 is charged by using the recharge tube 17 having the conical angle of the conical valve 16 different from that of the conical valve 16 at least once during the filling of the raw material, . Here, in the present invention, the conical angle of the conical valve 16 refers to the vertex angle (the vertical angle of the vertical plane)? Of the conical valve 16, as shown in Fig.

Since the inclination of the inclined surface of the conical valve differs depending on the angle of the cone, if the inclination of the inclined surface is different, the material can be introduced at a position different from the position where the material is charged in the case of filling the other material. If the conical angle of the conical valve is large, the raw material is discharged to the outside, and if the conical angle is small, the raw material is dropped near the center. By combining these, it is possible to prevent the height of the input raw material from being increased only by a specific portion, and the height of the input raw material can be smoothed. Therefore, there is no need to empty time for each raw material charge, and the melting proceeds efficiently. Thereby, the productivity of single crystal production can be effectively improved.

The conical angle? Of the conical valve 16 as shown in Fig. 4 is not particularly limited, but is preferably set in the range of 30 to 150 degrees.

When the temperature is more than 30 degrees, the height of the conical valve can be suppressed, so that the capacity of the return pipe is not reduced and is efficient. When the temperature is less than 150 degrees, the drop rate of the raw material does not drop too much, have. Further, the cone angle? Is more preferably in the range of 40 to 120 degrees. If it is more than 40 degrees, the dropping rate of the raw material is not too fast, and if it is 120 degrees or less, the conical valve is stable and stable when the raw material is supplied. Further, in the case of this conical angle?, It is also ensured that the injection position is not too far from the center of the crucible, and the raw material strongly hits the inner wall of the quartz crucible, depending on the relationship between the size of the quartz crucible and the size of the recharge tube. .

4, when the conical angle? Of the conical valve 16 is changed to change the conical angle? Of the conical valve 16 to 15 degrees or more, Is preferably used.

In the case of the conical valve having the conical angle different by 15 degrees or more as described above, it is possible to feed the raw material to a position which is certainly different from the input position of the raw material in filling the other raw materials, and the height of the input raw material into the quartz crucible becomes more uniform .

For example, as shown in Fig. 4, conical valves 16a, 16b and 16c having three levels of cone angle? Can be prepared, and the raw material can be charged by changing the conical valve used for each raw material charge. Alternatively, in the case of filling the raw material at least once, a conical valve having a different cone angle? May be used. For example, when the raw material is charged three times in succession, the first cone valve 16a, (16c), and the third is a conical valve (16a) in this order.

The raw material filling method of the present invention is preferably used when the raw material 14 is filled in the quartz crucible 6 having a diameter of 610 mm or more.

Such a large-diameter quartz crucible has a large capacity and the number of times of continuous filling of the raw material is increased, and the height of the charged raw material tends to be uneven because of its large diameter. The thickness of the rechargeable tube is basically the same as the thickness of the grown crystals, because it is limited by the gas rectifier. On the other hand, in quartz crucibles, a diameter of about three times of the roughly grown crystal diameter is used. Therefore, the distance from the rechargeable tube to the crucible wall is a distance to which the raw material of the remainder is to be blown, and is about the crystal diameter. That is, the size ratio is constant, and the distance to which the actual raw material is to be blown increases as the crucible diameter increases. Therefore, the present invention is suitable.

The method of filling a raw material of the present invention comprises the steps of filling a raw material 14 in a quartz crucible 6 by using the single crystal manufacturing apparatus 20 described above and a step of melting the raw material 14 in a quartz crucible 6 (4) by repeating the step of pulling up the single crystal (4) from the molten liquid (5) to obtain a plurality of single crystals (4) by using the same quartz crucible Lt; / RTI >

In this case, in the step of filling the raw material 14 in the pulling-up of the first single crystal 4 and / or the step of filling the raw material 14 in the pulling-up of each single crystal 4 after the second and / The raw material 14 is charged by the raw material charging method of the present invention.

It can be charged by the method of the present invention in addition to the charge of the raw material in the first pulling up of the single crystal or the raw material can be charged by the invention in the recharge at the second and subsequent pulling of the single crystal.

According to the present invention as described above, in the case of manufacturing a single crystal in the Czochralski method (including the MCZ method), it is possible to shorten the raw material filling time or the raw material melting time, and the productivity can be effectively improved.

Example

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto.

(Experiment)

As shown in Fig. 4, three levels of conical valves were prepared by dividing the cone angle [theta] by 100 degrees, 70 degrees, and 50 degrees. This was set at the bottom of the recharge tube, and the raw material was introduced into the recharge tube as shown in Fig.

Thereafter, a plate was placed on a quartz crucible at room temperature to select a silicon melt instead, and the raw material in the recharge tube was placed on the plate as shown in Fig. This experiment was performed using three levels of conical valves with different cone angles as shown in FIG.

As a result, as shown in Fig. 5 (a), the dropped material formed a donut shaped acid. Fig. 5 (b) shows the measurement of the height. 5 (b), the distance from the center of the quartz crucible to the inner wall was denoted by 1, As can be seen from Fig. 5 (b), as the conical angle? Increases, the peak of the acid moves to the outside of the crucible and the height of the mountain tends to decrease.

As described above, it was found that the position where the raw material falls can be controlled by dividing the conical angle of the conical valve. Conventionally, raw materials have been charged a plurality of times at only one kind of angle. However, the height of the donut-shaped mountain is increased at the same position, and there is a complicated operation such as waiting for the molten raw material to be melted to some extent and then the next injection, and it takes time to melt. However, since the drop position of the raw material is changed by changing the angle of the cone, it has been shown that the use of a conical valve that changes the angle of cone every time it is turned on, for example, This charging experiment was carried out at room temperature, but charging of raw materials such as recharge is actually carried out at a high temperature. First, the charged raw material starts to be melted when the following raw material is further charged. For this reason, the following Examples 1 to 3 and Comparative Examples were carried out under the high temperature condition of the actual apparatus.

(Example 1)

1, a quartz crucible having a diameter of 26 inches (660 mm) was provided in the main chamber, and a silicon single crystal of 8 inches (200 mm) in diameter was formed using a magnetic field-applied Czochralski method (MCZ method) .

After silicon single crystal was grown in this apparatus, 120 kg of raw material was further charged in the quartz crucible and melted. At this time, the raw materials were continuously injected three times with the same input amount of 40 kg. In the case of three doses, the conical angle (?) Of each conical valve was 50 degrees for the first administration, 70 degrees for the second administration, and 100 degrees for the third administration.

Since the inside of the main chamber is in a reduced pressure state, the recharge tube is mounted in the pulling chamber under atmospheric pressure, and then the pressure inside the pulling chamber is reduced to the same pressure as the main chamber by the vacuum pump. Thereafter, the recharge tube was lowered to the vicinity of the surface of the melt, and the opening was opened in the conical valve to perform the material feed. Then, the empty recharge tube was pulled up again in the pulling chamber, the gate valve was closed, and the pressure was returned to normal pressure. This operation was repeatedly carried out, and three times of the raw materials were charged.

As a result, it was possible to proceed without clogging because the acid was too high in the case of inputting the raw material, so that the work could not proceed without clogging. As a result, the time taken for melting could be shortened by 15% compared with the comparative example presented later.

(Example 2)

The conical angle of the conical valve was set at 100 degrees for the first administration, 50 degrees for the second administration, and 100 degrees for the third administration, and a total of 120 kg of the raw material was injected and melted in the same manner as in Example 1.

As a result, in the same manner as in Example 1, it was possible to work without clogging without causing a situation in which the acid was too high and could not be supplied when the raw material was supplied. As a result, the time taken for melting could be reduced by about 14% as compared with the comparative example presented later.

(Example 3)

A total of 120 kg of the raw material was injected and melted in the same manner as in Example 1, except that the conical angle of the conical valve was 100 degrees for the first administration, 70 degrees for the second administration, and 50 degrees for the third administration.

As a result, although the first administration and the second administration were possible without any clogging, since the height of the acid was slightly high when the third administration was put in, the third administration was started after waiting for the raw material to melt slightly. As a result, the time taken for melting could be shortened by about 8% as compared with the comparative example presented later.

(Comparative Example)

A total of 120 kg of the raw material was added and melted in the same manner as in Example 1, except that a conical valve having a cone angle of 70 degrees was used in all three administrations.

As a result, although the first administration and the second administration were possible without any clogging, the donut-shaped mountain height was too high when the third administration was put in, so the injection timing was waited for without opening the gate valve. Since the raw material started to be melted and the acid was lowered, the gate valve was opened, the return pipe was lowered, and the third feed was carried out. As a result, the melting time was longer than those of Examples 1 to 3 mentioned above.

In Examples 1 to 3, examples were shown in which the cone angles were gradually increased, or gradually reduced, or alternatively, large and small are alternately used, and three consecutive injections are made. However, the present invention is not limited to such an embodiment. The present invention can be applied to four or more times of continuous or two times of input, and also when the amounts of input are different, You can then select the appropriate change angle.

The present invention is not limited to the above embodiments. The above embodiments are illustrative and substantially the same as the technical ideas described in the claims of the present invention are included in the technical scope of the present invention.

1 - main chamber 2 - impression chamber
3 - Gate valve 4 - Single crystal
5 - Melt 6 - Quartz crucible
7 - Graphite Crucible 8 - Heater
9 - Insulation member 10 - Gas outlet
11 - gas inlet 12 - gas rectifier
13 - Heating element 14 - Raw material
15 - Cylindrical member 16 - conical valve
17 - Recharge tube 18 - Wire
20 - Single crystal manufacturing equipment

Claims (7)

A method for producing a single crystal having a step of filling a raw material in a quartz crucible, a step of melting the raw material in the quartz crucible to make a melt, and a step of pulling up a single crystal from the melt,
Wherein the raw material is contained in a quartz cylindrical member for containing the raw material and a conical valve for opening and closing a lower end opening of the cylindrical member in the step of filling the raw material in the quartz crucible, A raw material charging method in which a recharge tube is set in a chamber and an opening of the cylindrical member is opened in the conical valve so that a raw material contained in the recharge tube is charged into the quartz crucible,
Wherein said raw material is charged using said recharge tube having a cone angle different from a cone angle of said conical valve in charging said raw material at least once during said raw material charging which is performed two or more times in succession.
The method according to claim 1,
Wherein the conical angle of the conical valve is in the range of 30 to 150 degrees.
The method according to claim 1,
Wherein the raw material is charged using the recharge tube having a conical angle of at least 15 degrees when the conical valve is filled at least once with the raw material.
3. The method of claim 2,
Wherein the raw material is charged using the recharge tube having a conical angle of at least 15 degrees when the conical valve is filled at least once with the raw material.
5. The method according to any one of claims 1 to 4,
Wherein the quartz crucible has a diameter of 610 mm or more.
A step of filling a raw material in a quartz crucible; a step of melting the raw material in the quartz crucible to make a molten liquid; and a step of pulling up a single crystal from the molten liquid are repeated, and a plurality of single crystals are produced using the same quartz crucible As a method,
The method of filling a raw material according to any one of claims 1 to 4, wherein in the step of filling the raw material in the first pulling-up of the single crystal and / or the step of filling the raw material in the pulling of each single crystal after the second step And the raw material is filled with the raw material.
A step of filling a raw material in a quartz crucible; a step of melting the raw material in the quartz crucible to make a molten liquid; and a step of pulling up a single crystal from the molten liquid are repeated, and a plurality of single crystals are produced using the same quartz crucible As a method,
Filling the raw material by the raw material filling method according to claim 5 in the step of filling the raw material in the first pulling-up of the single crystal and / or the step of filling the raw material in the pulling-up of each single crystal after the second and / Wherein the single crystal is a single crystal.

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