Silicon single crystal manufacturing apparatus

Abstract

The present invention is an apparatus for producing a silicon single crystal, the apparatus comprising: a chamber in which a quartz crucible and a heater for heating and melting a silicon polycrystalline raw material in the quartz crucible are disposed to produce a raw material melt; a gas introduction pipe; the silicon single crystal manufacturing apparatus is an apparatus for manufacturing a silicon single crystal by a CZ method, and the gas discharge pipe has a plurality of pipes each having a joint portion and a pipe clip capable of liquid cooling by circulating cooling water, the joint portions of the plurality of pipes face each other by sandwiching a sealing material therebetween, and the gas discharge pipe is disposed between the joint portions of the plurality of pipes and the pipe clip. The plurality of pipes are connected to each other by clamping the facing joint parts with each other by the pipe clamp, and the sealing material between the joint parts can be cooled by liquid cooling of the pipe clamp. As a result, provided is a CZ silicon single crystal manufacturing apparatus in which the gas discharge piping is easy to handle and the deterioration of the sealing material between the piping can be prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to an apparatus for manufacturing a silicon single crystal by a Czochralski method (CZ method). BACKGROUND

[0002] As a method for manufacturing a silicon single crystal which is a basic material of a semiconductor integrated circuit, there is a Czochralski method (CZ method). In the CZ method, a high-purity silicon polycrystal raw material is put into a quartz crucible provided in a chamber, and the silicon polycrystal raw material is melted by a heater provided at the outer periphery of the quartz crucible. A seed crystal is immersed in the raw material melt (silicon melt), and the seed crystal is pulled up while being rotated, thereby growing a single crystal, and a cylindrical silicon single crystal is manufactured.

[0003] In the CZ method, as a discharge method, there is known a configuration in which a vacuum pump is connected to a manufacturing apparatus (a crystal pulling machine) for a silicon single crystal via a gas discharge pipe (Patent Literature 1).

[0004] PRIOR ART DOCUMENT PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2017-114709 SUMMARY

[0005] (1) Problem to be Solved In the manufacturing apparatus configured as described above, the gas discharge pipe is connected by a plurality of pipes, and the pipes are connected with a sealing material (for example, an O-ring) interposed between the joint portions thereof. Then, when the silicon single crystal is manufactured, the non-active gas in the chamber is heated by the heater, and thus the non-active gas becomes high temperature. Although the non-active gas that has become high temperature is discharged by the vacuum pump, heat is transferred to the sealing material via the joint portions of the gas discharge pipe, and the sealing material is deteriorated, and there is a possibility that the non-active gas leaks during the manufacturing of the silicon single crystal. When there is a leak, the chamber of the silicon single crystal manufacturing apparatus cannot be maintained in vacuum, and there is a possibility that the quality is affected.

[0006] When there is a leak, it is necessary to determine the position of the leak and replace the sealing material, but since the number of pipe joint portions is large, it takes time to check, and during this period, the silicon single crystal cannot be manufactured.

[0007] In addition, silicon oxide is generated during the manufacturing of the silicon single crystal, and the silicon oxide is deposited in the gas discharge pipe, and thus after the manufacturing of the silicon single crystal, the gas discharge pipe is disassembled and the silicon oxide is removed. In order to clean, it is desirable that the gas discharge pipe (the plurality of pipes) is a structure that is lightweight, easy to handle, and easy to disassemble.

[0008] Figure 3 is an explanatory view showing one example of a cooling mechanism of the gas discharge pipe 110 of the related art.Figure 3 The left drawing is a configuration explanatory view from the axial direction of the gas exhaust pipe 110, and the right drawing is a configuration explanatory view at the B-B' section of the left drawing. The joint portions 115 of the two adjacent pipes 112 (112a, 112b) are connected to each other with the sealing material 114 interposed therebetween by fastening the pipe clamp 113 (113a, 113b) split into two in a circular ring shape with bolts. In the related art, in order to prevent the joint portions 115 from becoming high temperature, a water-cooling pipe 120 is wound around the outer periphery of the pipe body of the gas exhaust pipe 110 (i.e., the pipe body of the pipe 112) and is welded, and water is circulated through the water-cooling pipe 120, thereby preventing the gas exhaust pipe 110 from becoming high temperature.

[0009] In the method of the related art, the outer peripheral portion of the pipe body of the gas exhaust pipe is cooled, and therefore the joint portions and the vicinity of the sealing material are difficult to cool, and there is a case where the sealing material is deteriorated by heat. In addition, when the gas exhaust pipe is cleaned, the pipe must be disassembled and detached. However, as described above, since the water-cooling pipe is welded to the pipe and is heavy, the operability deteriorates.

[0010] The present application is made to solve the above problems, and aims to provide a CZ silicon single crystal manufacturing apparatus in which a gas exhaust pipe is easy to handle, and deterioration of the sealing material between the pipes can be prevented.

[0011] (2) Technical Solution In order to achieve the above object, the present application provides a silicon single crystal manufacturing apparatus including: a chamber in which a quartz crucible that contains a silicon polycrystal raw material and a heater that heats and melts the silicon polycrystal raw material in the quartz crucible to produce a raw material melt are disposed; a gas introduction pipe for introducing a non-reactive gas into the chamber; and a gas exhaust pipe for exhausting the non-reactive gas that has been introduced into the chamber, the silicon single crystal manufacturing apparatus manufacturing a silicon single crystal from the raw material melt by a Czochralski method, the silicon single crystal manufacturing apparatus being characterized in that the gas exhaust pipe has a plurality of pipes each having a joint portion, and a pipe clamp that can perform liquid cooling by circulating cooling water, the joint portions of the plurality of pipes are opposed to each other with a sealing material interposed therebetween, and the opposed joint portions are clamped to each other by the pipe clamp, whereby the plurality of pipes are connected to each other, and cooling of the sealing material between the joint portions can be performed by the liquid cooling of the pipe clamp.

[0012] If this silicon single crystal production apparatus of the present application, the sealing material between the joint portions of the gas exhaust pipe can be effectively cooled by liquid cooling of the pipe clamp, and deterioration of the sealing material due to heat can be prevented. Therefore, the necessity of leak inspection and replacement of the sealing material due to deterioration of the sealing material in the conventional apparatus can be eliminated or at least reduced in frequency. As a result, maintenance cost can be reduced, and quality deterioration of the silicon single crystal due to occurrence of a leak can be prevented, so that production loss of the silicon single crystal can be reduced.

[0013] In addition, even if the water cooling pipe is not welded to the outer periphery of the pipe body of the pipe as in the conventional apparatus for preventing deterioration of the sealing material, the sealing material can be sufficiently cooled, so that weight reduction of the plurality of pipes constituting the gas exhaust pipe can be sought for easy handling. Therefore, even when removing deposits in the pipe, the operation can be easily performed. Moreover, the modification cost using the liquid cooling type pipe clamp can be more inexpensive than that of the conventional water cooling type (water cooling pipe is welded to the outer periphery of the pipe).

[0014] (Three) Advantageous Effects If the silicon single crystal production apparatus of the present application, deterioration of the sealing material in the gas exhaust pipe due to heat can be prevented. Therefore, generation of a gas leak due to deteriorated sealing material can be prevented, and necessity of various operations accompanying the leak and cost required therefor, and quality deterioration of the single crystal can be prevented. Moreover, the pipe itself is lightweight, and in terms of cleaning inside the pipe, operability can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic side view showing one example of a silicon single crystal production apparatus of the present application.

[0016] Figure 2 is an explanatory view showing one example of a configuration of a gas exhaust pipe. The left drawing is a configuration explanatory view observed from the axial direction. The right drawing is a configuration explanatory view at the A-A' cross section of the left drawing.

[0017] Figure 3 is an explanatory view showing one example of a cooling mechanism of a gas exhaust pipe in a conventional apparatus. The left drawing is a configuration explanatory view observed from the axial direction. The right drawing is a configuration explanatory view at the B-B' cross section of the left drawing. DETAILED DESCRIPTION

[0018] Figure 1An example of a silicon single crystal manufacturing apparatus by the Czochralski method according to the present application is shown. The silicon single crystal manufacturing apparatus 1 has a chamber 2. Inside a quartz crucible 4 disposed in a graphite crucible 3 in the chamber 2 is filled with a raw material melt 5 from which a silicon single crystal 6 is pulled. A heater 7 for heating the raw material melt 5 is disposed at the outer periphery of the graphite crucible 3 in the chamber 2, and at the outer periphery of the heater 7, a heat insulating member 8 is disposed for insulation from the heat from the heater 7.

[0019] In addition, a gas introduction pipe 9 is disposed at the upper portion of the chamber 2, and a gas discharge pipe 10 is disposed at the lower portion. Furthermore, a vacuum pump 11 is connected to the end of the gas discharge pipe 10. An inactive gas such as argon is introduced into the chamber 2 from the gas introduction pipe 9, flows downward, is discharged to the outside through the gas discharge pipe 10 and the vacuum pump 11.

[0020] In manufacturing the silicon single crystal 6, first, a silicon polycrystal raw material is housed in the quartz crucible 4, and is heated by the heater 7 to make the raw material melt 5. After immersing a seed crystal S suspended by a wire in the raw material melt 5, the wire is pulled to grow the silicon single crystal 6. Furthermore, the inactive gas is introduced into the chamber 2 from the gas introduction pipe 9, and is discharged from the gas discharge pipe 10.

[0021] Here, the configuration of the gas discharge pipe 10 in the silicon single crystal manufacturing apparatus 1 according to the present application is described. Figure 2 An example of the configuration of the gas discharge pipe 10 is shown. Figure 2 The left drawing is a configuration explanatory view as viewed from the axial direction of the gas discharge pipe 10, and the right drawing is a configuration explanatory view of the A-A' section of the left drawing.

[0022] The gas discharge pipe 10 mainly has a plurality of pipes 12 (12a, 12b), a pipe clamp 13 capable of liquid cooling, and a sealing material 14.

[0023] The pipe 12 itself only needs to have a joint portion (flange or the like) 15 at the end portion. In Figure 2 In the present embodiment, in particular, as is clear from the right drawing, a step is provided from the pipe main body to the joint portion 15, but the shape of the pipe 12 according to the present application is not limited to this, and the step can not be present.

[0024] In addition, as the sealing material 14, for example, an O-ring can be cited, but it is not limited to this.

[0025] As shown in the left drawing of Figure 2 In the plurality of pipes 12 (12a, 12b) adjacent to each other, the respective joint portions 15 oppose each other with the sealing material 14 interposed therebetween, as shown in the left drawing. Furthermore, as shown in the right drawing, the opposing joint portions 15 are interposed by the clamping portions 18 of the pipe clamp 13, whereby the plurality of pipes 12 adjacent to each other are connected to each other.

[0026] Also, in the left drawing, the circular solid line and the circular dotted line are depicted as almost concentric circles, and these indicate the positions of the pipe 12 and the clamping portion 18. The circular solid line of the innermost periphery in the left drawing indicates the inner peripheral surface 12s of the pipe 12 shown in the right drawing, and the circular dotted line of the outermost periphery in the left drawing indicates the inner bottom surface 18s of the clamping portion 18 shown in the right drawing.

[0027] The pipe clamp 13 can be provided so as to be detachable with respect to the pipe 12 (the joint portion 15). Since it is detachable, both the pipe clamp 13 itself and the pipe 12 itself are easily handled, and it is easy to clean the inside of the pipe 12. As one example, as shown in the left drawing of FIG. 10, it can be made into a split structure (13a, 13b), and be made of a material with good thermal conductivity (for example, aluminum). Of course, the number of splits is not particularly limited, and can be appropriately decided in accordance with the thickness and the like of the pipe 12. Figure 2

[0028] In addition, the pipe clamp 13 has a liquid cooling mechanism based on the flow of cooling water, for example, is provided with the through-hole 16 for flowing cooling water inside. Also, the inlet of the through-hole 16 becomes a tapered screw shape for connecting the cooling water delivery pipe 17 from the outside. That is, the inlet of the through-hole 16 is an internal screw, and the cooling water delivery pipe 17 inserted into this is an external screw.

[0029] The size (thickness) of the through-hole 16 is not particularly limited, but for example, can be set to a size of 40% to 50% of the thickness of the pipe clamp 13. If the thickness of the through-hole 16 is this degree, liquid cooling can be performed more efficiently. In addition, with respect to the tapered screw (external screw, internal screw), it can be set so that the sizes cooperate with each other.

[0030] Although the through-hole 16 of FIG. 10 becomes a linear shape in which water flows up and down, this shape is not particularly limited, and can be set to various shapes in consideration of the efficiency and the like of cooling. Figure 2 Also, although the type of connecting the through-hole 16 and the cooling water delivery pipe 17 is described here, it can also be set to a type different from this, for example, a type in which the cooling water delivery pipe 17 penetrates the inside of the pipe clamp 13.

[0031] When assembling the gas discharge pipe 10, the joint portions 15 of the plurality of pipes 12 (12a, 12b) are opposed to each other in a state in which they sandwich an O-ring or the like as a sealing material 14 therebetween, and with respect to the outer peripheries of the joint portions 15 of the pair, as shown in the left drawing of FIG. 10, the split pipe clamps 13a, 13b are brought close from the left and right. Then, as shown in the right drawing of FIG. 10, the joint portions 15 of the pair are inserted and fitted into the clamping portions 18 of the pipe clamps 13a, 13b, and as shown in the left drawing of FIG. 11, the cooling water delivery pipe 17 is connected to the through-holes 16 of the pipe clamps 13a, 13b.

[0032] Figure 2 Figure 2 Figure 2 ​​​​The pipe clamps 13a, 13b are fastened to each other with the bolts 19 as shown in the left drawing of FIG. 1, thereby sealing. Figure 2 In the left drawing of FIG. 1, the joint portions 15 are visible in the gaps between the left and right pipe clamps 13a, 13b.

[0033] Then, the cooling water supply pipe 17 is connected to the pipe clamps 13, and Figure 2 In the case of FIG. 1, the cooling water flows from the upper side to the lower side, but the direction can be reversed. Also, the temperature of the cooling water can be set to about 20°C, for example, but is not limited thereto. The temperature of the cooling water can be appropriately determined in accordance with the temperature of the gas in the gas exhaust pipe 10 and the distance from the chamber 2, etc. By the flow of the cooling water, the pipe clamps 13 themselves are liquid-cooled, and the sealing material 14 between the joint portions 15 held by the pipe clamps 13 can be effectively cooled.

[0034] In the cooling mechanism in the gas exhaust pipe of the conventional apparatus, water cooling is performed by the water-cooled pipe that is located on both sides of the joint portions of the plurality of pipes (across the sealing material) and is welded to the outer periphery of the pipe body. However, the cooling mechanism in the manufacturing apparatus of the present application is liquid-cooled type as described above, in which the pipe clamps that hold the joint portions of the pipes (across the sealing material) are liquid-cooled by the cooling water, thereby cooling the joint portions held by the pipe clamps and further the sealing material therebetween.

[0035] Since the gas exhaust pipe is provided with such a cooling mechanism, the weight and handling of the pipe itself are more excellent than in the past, and the sealing material can be more effectively cooled than in the past, and deterioration of the sealing material due to heat of the high-temperature gas passing through the gas exhaust pipe can be prevented. Therefore, not only the cleaning operation of the deposits in the pipe becomes easy, but also generation of gas leakage due to deterioration of the sealing material can be prevented. Thus, the maintenance cost of the various operations such as inspection when leakage occurs and replacement of the sealing material, etc. can be reduced, and the quality of the silicon single crystal manufactured can be prevented from being deteriorated due to gas leakage.

[0036] Furthermore, the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and technical solutions having substantially the same structure as that described in the technical idea of the claims of the present application and achieving the same effects are all included in the technical scope of the present application.

Claims

1. A silicon single crystal production apparatus comprising: a chamber in which a quartz crucible that contains a silicon polycrystal raw material and a heater that heats and melts the silicon polycrystal raw material in the quartz crucible to produce a raw material melt are disposed; a gas introduction pipe for introducing a non-reactive gas into the chamber; and a gas discharge pipe for discharging the non-reactive gas that has been introduced into the chamber, the silicon single crystal production apparatus producing a silicon single crystal from the raw material melt by the Czochralski method, the silicon single crystal production apparatus being characterized in that: the gas discharge pipe has a plurality of pipes each having a joint portion, and a pipe clamp that is capable of liquid cooling by flowing cooling water, the joint portions of the plurality of pipes are opposed to each other with a sealing material interposed therebetween, and the opposed joint portions are clamped to each other by the pipe clamp, whereby the plurality of pipes are connected to each other, and cooling of the sealing material between the joint portions is performed by liquid cooling of the pipe clamp.

2. The silicon single crystal production apparatus according to claim 1, wherein the pipe clamp is a pipe clamp that is capable of liquid cooling by flowing cooling water.

3. The silicon single crystal production apparatus according to claim 1 or 2, wherein the pipe clamp is a pipe clamp that is capable of liquid cooling by flowing cooling water.

4. The silicon single crystal production apparatus according to any one of claims 1 to 3, wherein the pipe clamp is a pipe clamp that is capable of liquid cooling by flowing cooling water.

5. The silicon single crystal production apparatus according to any one of claims 1 to 4, wherein the pipe clamp is a pipe clamp that is capable of liquid cooling by flowing cooling water. ​ ​ ​ ​

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