Single crystal manufacturing apparatus

Abstract

The present invention provides a single crystal manufacturing apparatus capable of achieving high speed of growth of a single crystal by effectively cooling the single crystal in growth. The single crystal manufacturing apparatus has a main chamber accommodating a crucible containing a raw material melt, a pulling chamber pulling and accommodating the single crystal, and a cooling cylinder extending from a top of the main chamber to a surface of the raw material melt in a manner of surrounding the single crystal in growth and being forcedly cooled, and further has a cooling auxiliary cylinder fitted to an inner side of the cooling cylinder and a diameter expanding member fitted to the cooling auxiliary cylinder, the cooling auxiliary cylinder has a slit penetrating in an axial direction, the cooling auxiliary cylinder is tightly fitted to an inner surface of the cooling cylinder by press-fitting of the diameter expanding member, the cooling auxiliary cylinder has a flange portion extending to an outer side in a manner of covering a bottom surface of the cooling cylinder opposite to the raw material melt, and the cooling cylinder bottom surface, the tightly fitting auxiliary member and the cooling auxiliary cylinder flange portion are tightly fitted by a tightly fitting auxiliary member fitted between the cooling auxiliary cylinder flange portion and the cooling cylinder bottom surface.

Description

Technical Field

[0001] This invention relates to an apparatus for manufacturing single-crystal silicon and the like based on the Czeklauski process. Background Technology

[0002] Semiconductor substrates such as silicon or gallium arsenide are made of single crystals and are used in memory devices for computers ranging from small to large, requiring large capacity, low cost, and high quality.

[0003] Previously, the Czerklaussky process (CZ process) was known as one of the single crystal manufacturing methods for producing single crystals that meet the requirements of these semiconductor substrates. This method involves impregnating a seed crystal in molten semiconductor material contained in a crucible and then pulling it out to produce a large-diameter, high-quality single crystal.

[0004] The following section uses the cultivation of monocrystalline silicon as an example, referring to... Figure 8 A single crystal manufacturing apparatus based on the existing CZ method is described.

[0005] In the single crystal manufacturing apparatus (existing example) 100 used in the CZ method for growing single crystals, a liftable quartz crucible 3 for containing raw material molten liquid 5, a graphite crucible 4 for supporting the quartz crucible 3, and a heater 2 arranged to surround the crucible 3 and 4 are generally arranged in the main chamber 1 for growing single crystal 6. A pulling chamber 7 for containing and taking out the grown single crystal 6 is connected to the upper part of the main chamber 1.

[0006] The single crystal manufacturing apparatus 100 may also include: a gas inlet 11, a gas outlet 12, a cooling auxiliary cylinder 13, a cooling cylinder 14, and a heat shielding component 22. These will be described later.

[0007] When manufacturing a single crystal (hereinafter sometimes simply referred to as a crystal) 6 using such a single crystal manufacturing apparatus 100, a seed crystal 8 is immersed in the raw material melt 5 and gently pulled upward while rotating, thereby growing a rod-shaped single crystal 6. At the same time, in order to keep the height of the melt surface used to obtain the desired diameter and crystal quality constant, the crucibles 3 and 4 are raised in conjunction with the crystal growth.

[0008] Subsequently, during the cultivation of single crystals, the seed crystal 8, mounted on the seed holder 9, is immersed in the molten raw material. While rotating the seed crystal 8 in the desired direction using a lifting mechanism (not shown), the wire 10 is gently wound up, allowing the single crystal 6 to grow at the leading end of the seed crystal 8. At this time, in order to eliminate dislocations caused by thermal shock when the seed crystal 8 comes into contact with the molten material, the initial crystallization is temporarily reduced to about 3-5 mm. Once the dislocations disappear, the diameter is expanded to the desired position, allowing the single crystal 6 of the target quality to grow.

[0009] At this point, although the pulling speed of the sizing section with a constant diameter of single crystal 6 also depends on the diameter of the single crystal 6 being pulled, it is very slow at 0.4~2.0 mm / min. If forced to pull quickly, the growing single crystal 6 will deform and a cylindrical part with a constant diameter cannot be obtained. Alternatively, slip dislocations may occur on the single crystal 6, causing the single crystal 6 to separate from the melt and become a product. This limits the ability to achieve high-speed crystal growth.

[0010] However, in the manufacturing of single crystal 6 based on the above CZ method, in order to improve productivity and reduce costs, it is important to increase the growth rate of single crystal 6. To date, various improvements have been made to achieve the goal of increasing the growth rate of single crystal 6.

[0011] It is known that the growth rate of single crystal 6 is determined by its thermal equilibrium. To increase its growth rate, it is only necessary to effectively remove the heat released from the surface of single crystal 6. If the cooling effect of single crystal 6 can be improved, single crystal 6 can be manufactured more efficiently.

[0012] Furthermore, it is known that the quality of the crystal changes due to the cooling rate of the single crystal 6. For example, in single-crystal silicon, growth-in defects formed in the single crystal can be controlled by the ratio of the temperature gradient within the crystal to the pulling rate (growth rate) of the single crystal. By controlling this ratio, it is also possible to pull a defect-free single crystal 6 (Patent Document 1).

[0013] Therefore, improving the cooling effect of growing single crystal 6 is important, both in manufacturing defect-free crystals and in increasing productivity by accelerating the growth rate of single crystal 6.

[0014] Existing technical documents

[0015] Patent documents

[0016] Patent Document 1: Japanese Patent Application Publication No. 11-157996

[0017] Patent Document 2: International Publication No. WO01 / 57293

[0018] Patent Document 3: Japanese Patent Application Publication No. 2009-161416

[0019] Patent Document 4: Japanese Patent Application Publication No. 2020-152612

[0020] Patent Document 5: Japanese Patent Application Publication No. 2014-43386 Summary of the Invention

[0021] (a) Technical problems to be solved

[0022] Therefore, as an effective method for cooling single crystals, a method of arranging a water-cooled cooling cylinder around the crystal has been proposed (Patent Document 2). In this method, by combining the cooling cylinder and cooling auxiliary components, radiative heat from the heater to the crystal is blocked, and the crystal is cooled by the cooling cylinder as it moves upward. However, there is a problem that the cooling effect is slightly weaker before the crystal reaches the cooling cylinder.

[0023] Furthermore, Patent Document 3 describes a method for extending graphite materials by fitting them into a cooling cylinder. However, in this method, the graphite material extending from the cooling cylinder is subjected to heat from the outside and cannot achieve a sufficient cooling effect. Moreover, it is difficult to make the cooling cylinder and the graphite material fit tightly together, and effective heat transfer from the graphite material to the cooling cylinder cannot be achieved.

[0024] To address this issue, in patent document 4, such as Figure 8 As shown, a method for fitting the cooling auxiliary cylinder 13 onto the cooling cylinder 14 is illustrated. Furthermore, by fitting a diameter-enlarging component onto the cooling auxiliary cylinder, the adhesion between the cooling cylinder and the cooling auxiliary cylinder can be improved, thereby enhancing heat transfer from the cooling auxiliary cylinder to the cooling cylinder and increasing the crystal pulling speed.

[0025] However, simply increasing the adhesion between the inner surface of the cooling cylinder and the outer surface of the cooling auxiliary cylinder cannot be expected to further improve the heat transfer from the cooling auxiliary cylinder to the cooling cylinder, thus limiting the speed of crystal growth.

[0026] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a single crystal manufacturing apparatus that can achieve high-speed growth of the single crystal by effectively cooling the single crystal during cultivation.

[0027] (II) Technical Solution

[0028] To address the aforementioned problems, the present invention provides a single crystal manufacturing apparatus that grows single crystals using the Czeklaussky method. The apparatus comprises: a main chamber housing a crucible containing molten raw material and a heater for heating the molten raw material; a pulling chamber connected to the upper part of the main chamber for pulling and housing the grown single crystal; and a cooling cylinder extending from at least the top of the main chamber toward the surface of the molten raw material in a manner surrounding the pulled single crystal and forcibly cooled by a cooling medium. The apparatus is characterized by further comprising a cooling auxiliary cylinder fitted inside the cooling cylinder and a fitting... The cooling auxiliary cylinder has a diameter enlargement component, and the cooling auxiliary cylinder has an axially penetrating slit. The cooling auxiliary cylinder is pressed against the inner surface of the cooling cylinder by the diameter enlargement component. The cooling auxiliary cylinder has a flange portion that extends outward to cover the bottom surface of the cooling cylinder opposite to the raw material melt. The bottom surface of the cooling cylinder, the clamping auxiliary component, and the flange portion of the cooling auxiliary cylinder are pressed together by a clamping auxiliary component that fits between the flange portion of the cooling auxiliary cylinder and the bottom surface of the cooling cylinder.

[0029] According to this single crystal manufacturing apparatus, the cooling auxiliary tube is fitted into the cooling tube, improving the adhesion between the inner surface of the cooling tube and the outer surface of the cooling auxiliary tube. Furthermore, the bottom surface of the cooling tube, which faces the molten raw material, and the flange of the cooling auxiliary tube are pressed together through a bonding auxiliary component. Therefore, the cooling auxiliary tube is cooled to a lower temperature, allowing for greater dissipation of radiative heat from the crystal and enabling a higher crystal growth rate. In other words, according to the present invention, a single crystal manufacturing apparatus can be provided that achieves a high growth rate of the single crystal by effectively cooling the growing single crystal.

[0030] Preferably, the material of the cooling auxiliary cylinder is any one of graphite, carbon composite material, stainless steel, molybdenum and tungsten.

[0031] If the cooling auxiliary cylinder is made of these materials, it can effectively absorb the radiant heat from the single crystal and effectively transfer that heat to the cooling cylinder.

[0032] Preferably, the material of the bonding auxiliary component is any one of graphite, carbon composite material, stainless steel, molybdenum and tungsten.

[0033] If these materials are used to attach auxiliary components, they can effectively absorb radiant heat from the single crystal and transfer that heat to the cooling cylinder.

[0034] Preferably, the bonding auxiliary component has: a protrusion that faces the bottom surface of the cooling cylinder and the flange of the cooling auxiliary cylinder opposite to the raw material molten liquid; and an arcuate portion that extends upward and downward toward the protrusion.

[0035] The arc-shaped portion is concentric with the outer periphery of the cooling cylinder and the cooling auxiliary cylinder.

[0036] The surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is tapered.

[0037] By extending the arcuate portion to a position higher than the protrusion, the auxiliary component is brought close to the outer surface of the cooling cylinder, which is forcibly cooled by the cooling medium, thus effectively cooling the auxiliary component. By keeping the auxiliary component at a low temperature, heat from the single crystal can be effectively dissipated.

[0038] Furthermore, a taper is provided on the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder, so that even if there are dimensional tolerances between the cooling cylinder and the cooling auxiliary cylinder, they can be firmly attached by pressing in the protrusion of the fitting auxiliary component.

[0039] Preferably, the cone angle of the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is 5~25°.

[0040] If the cone angle is within this range, it can prevent the support and fixation of the auxiliary component from becoming difficult, and can ensure sufficient clearance between the outer circumferential surface of the cooling cylinder and the inner circumferential surface of the auxiliary component.

[0041] Preferably, a first cylindrical portion and a second cylindrical portion are formed downwardly on the inner and outer peripheries of the flange portion of the cooling auxiliary cylinder, separated by a groove portion.

[0042] A threaded hole is provided on the outer peripheral surface of the second cylindrical portion on the outer peripheral side.

[0043] The fitting auxiliary component has a through hole at a position corresponding to the threaded hole in the second cylindrical portion of the cooling auxiliary cylinder.

[0044] The cooling auxiliary cylinder and the bonding auxiliary component are fastened and fixed by bolts that pass through the through hole and are screwed into the threaded hole.

[0045] If such a single-crystal manufacturing device is used, the auxiliary components can be pressed in and fitted more firmly, and detachment can be prevented more reliably.

[0046] Preferably, the bolt is made of any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

[0047] Bolts made of this material can withstand the high temperatures inside the furnace during operation and radiation from furnace components.

[0048] (III) Beneficial Effects

[0049] As described above, the single crystal manufacturing apparatus of the present invention includes a forced-cooling cooling cylinder, a cooling auxiliary cylinder fitted with the cooling cylinder, a diameter enlargement member, and a bonding auxiliary member. While pressing the diameter enlargement member in and bonding the outer surface of the cooling auxiliary cylinder to the inner surface of the cooling cylinder, the bonding auxiliary member is fitted between the bottom surface of the cooling cylinder (opposite to the molten raw material) and the flange portion of the cooling auxiliary cylinder, thereby reducing the temperature of the cooling auxiliary cylinder. This effectively dissipates heat from the growing single crystal and enables a high-speed growth of the single crystal. Attached Figure Description

[0050] Figure 1 This is a schematic cross-sectional view illustrating an example of the single crystal manufacturing apparatus of the present invention.

[0051] Figure 2 It means Figure 1 Enlarged cross-sectional view of the cooling cylinder, cooling auxiliary cylinder, bonding auxiliary component, and diameter enlargement component in the single crystal manufacturing apparatus.

[0052] Figure 3 This is a schematic perspective view showing an example of the diameter enlargement component and cooling auxiliary cylinder of the present invention.

[0053] Figure 4 This is a schematic cross-sectional view showing the single crystal manufacturing apparatus used in Example 1.

[0054] Figure 5 This is an enlarged cross-sectional view showing the cooling cylinder, cooling auxiliary cylinder, bonding auxiliary component, and diameter enlargement component of the single crystal manufacturing apparatus used in Example 1.

[0055] Figure 6 This is a schematic cross-sectional view of the single crystal manufacturing apparatus used in Comparative Example 1.

[0056] Figure 7 This is a schematic cross-sectional view of the single crystal manufacturing apparatus used in Comparative Example 2.

[0057] Figure 8 This is a schematic cross-sectional view showing an example of an existing single crystal manufacturing apparatus.

[0058] Explanation of reference numerals in the attached figures

[0059] 1-Main chamber; 1a-Top; 2-Heater; 3-Quartz crucible; 4-Graphite crucible; 5-Raw material melt; 6-Single crystal; 7-Pulling chamber; 8-Seed crystal; 9-Seed crystal holder; 10-Metal wire; 11-Gas inlet; 12-Gas outlet; 13-Cooling auxiliary cylinder; 13a-Slit; 14-Cooling cylinder; 14a-Bottom surface; 15-Fitting auxiliary component; 15a-Protrusion; 15b, 15c-Arc portion; 15d-Surface in contact with flange (conical surface); 15e-Through hole; 16-Flange portion of cooling auxiliary cylinder; 17-Diameter enlargement component; 18-Fixing bolt; 19-First cylindrical portion; 20-Second cylindrical portion; 21-Groove portion; 22-Heat shielding component; 23-Threaded hole; 100, 200, 300, 400, 500-Single crystal manufacturing apparatus. Detailed Implementation

[0060] As mentioned above, in CZ-based single crystal manufacturing, increasing the growth rate of single crystals is an important means to improve productivity and reduce costs. To increase the growth rate of single crystals, it is known that it is only necessary to effectively remove the radiative heat from the single crystal and increase the temperature gradient of crystallization.

[0061] To solve this problem, as shown in Patent Document 4, the following technology has been developed: by embedding a cooling auxiliary cylinder into the inner surface of the cooling cylinder, the heat of the growing single crystal can be effectively discharged, thereby achieving a high growth rate of the single crystal. The cooling cylinder extends from the top of the main chamber to the raw material melt in a manner that surrounds the single crystal being pulled, and is forcibly cooled by the cooling medium.

[0062] However, there are limitations to the tightness of the contact between the cooling cylinder and the cooling auxiliary cylinder. Furthermore, while a thicker and longer cooling auxiliary cylinder has a higher heat capacity, the temperature rises further away from the contact area with the cooling cylinder, thus limiting its potential for increasing crystal growth speed. In the existing technology, it is difficult to further reduce the cooling cylinder temperature, thus limiting the potential for higher crystal growth speeds. For further increasing crystal growth speeds, it is crucial to improve the tightness of the contact between the cooling cylinder and the cooling auxiliary components, while simultaneously increasing the contact area to effectively reduce the temperature of the cooling auxiliary cylinder.

[0063] The inventors conducted in-depth research on the above-mentioned issues and found that by using a scheme that "has a cooling cylinder that is forced to cool, a cooling auxiliary cylinder that is fitted into the cooling cylinder, a diameter enlargement component, and a bonding auxiliary component, the diameter enlargement component is pressed in and the outer surface of the cooling auxiliary cylinder is pressed tightly against the inner surface of the cooling cylinder, and the bonding auxiliary component is fitted between the bottom surface of the cooling cylinder opposite to the raw material melt and the flange of the cooling auxiliary cylinder", the cooling auxiliary cylinder can be cooled to a low temperature, thereby effectively dissipating the heat from the growing single crystal and achieving a high growth rate of the single crystal, thus completing the present invention.

[0064] That is, the present invention is a single crystal manufacturing apparatus that grows single crystals using the Czeklaussky method. The apparatus comprises: a main chamber housing a crucible containing molten raw material and a heater for heating the molten raw material; a pulling chamber connected to the upper part of the main chamber for pulling and housing the grown single crystal; and a cooling cylinder extending from at least the top of the main chamber toward the surface of the molten raw material in a manner surrounding the pulled single crystal, and forcibly cooled by a cooling medium.

[0065] Its features are,

[0066] It also includes a cooling auxiliary cylinder fitted inside the cooling cylinder and a diameter-enlarging component fitted inside the cooling auxiliary cylinder.

[0067] The cooling auxiliary cylinder has a slit that runs through the entire axial direction.

[0068] The cooling auxiliary cylinder is pressed into place against the inner surface of the cooling cylinder by the enlarging diameter component.

[0069] The cooling auxiliary cylinder has a flange that extends outward to cover the bottom surface of the cooling cylinder opposite to the raw material molten liquid.

[0070] By using a fastening auxiliary component that fits between the flange of the cooling auxiliary cylinder and the bottom surface of the cooling cylinder, the bottom surface of the cooling cylinder, the fastening auxiliary component, and the flange of the cooling auxiliary cylinder are brought into close contact.

[0071] In addition, Patent Document 5 discloses an HZ structure in which the inner surface of the cooling cylinder is pressed tightly against the cooling cylinder using a cooling auxiliary cylinder and the bottom surface of the cooling cylinder opposite to the molten liquid surface is covered by a heat insulation component.

[0072] However, neither Patent Document 5 nor the aforementioned Patent Documents 1 to 4 discloses an HZ structure in which an auxiliary component is fitted and tightly attached between the bottom surface of the cooling cylinder and the flange of the cooling auxiliary cylinder, thus ensuring that the two are tightly attached.

[0073] The following is for reference Figure 1 and Figure 2 Here is a detailed description of one embodiment of the present invention. Additionally, descriptions of structures identical to those in existing devices are sometimes appropriately omitted.

[0074] Figure 1 This is a schematic cross-sectional view illustrating an example of the single crystal manufacturing apparatus of the present invention. Figure 2 It means Figure 1 Enlarged cross-sectional view of the cooling cylinder, cooling auxiliary cylinder, bonding auxiliary component, and diameter enlargement component of the single crystal manufacturing apparatus.

[0075] An example of the single crystal manufacturing apparatus 200 of the present invention includes: a main chamber 1, which houses a quartz crucible 3 and a graphite crucible 4 for containing raw material melt 5 and a heater 2 for heating the raw material melt 5; a pulling chamber 7, which is connected to the upper part of the main chamber 1 for pulling and housing the grown single crystal 6; a cooling cylinder 14, which extends from at least the top 1a of the main chamber 1 toward the raw material melt 5 in a manner that surrounds the pulled single crystal 6 and is forcibly cooled by a cooling medium; and a cooling auxiliary cylinder 13, which is fitted inside the cooling cylinder 14.

[0076] The cooling auxiliary cylinder 13 of the single crystal manufacturing apparatus 200 has a flange 16, which extends outward in a manner that covers the bottom surface 14a of the cooling cylinder 14 opposite to the raw material melt 5.

[0077] Furthermore, in the single crystal manufacturing apparatus 200, the bottom surface 14a of the cooling cylinder 14, the adhesive auxiliary member 15, and the flange portion 16 of the cooling auxiliary cylinder 13 are brought into close contact by the fitting auxiliary member 15 fitted between the flange portion 16 of the cooling auxiliary cylinder 13 and the bottom surface 14a of the cooling cylinder 14.

[0078] Figure 2 This is an enlarged cross-sectional view showing the cooling cylinder 14, the cooling auxiliary cylinder 13, and the bonding auxiliary component 15. The bonding auxiliary component 15 is fitted between the bottom surface 14a of the cooling cylinder, which is opposite to the raw material molten material, and the flange portion 16 of the cooling auxiliary cylinder 13. The bottom surface 14a of the cooling cylinder and the flange portion 16 of the cooling auxiliary cylinder 13 are bonded together through the bonding auxiliary component 15. The bonding auxiliary component 15 has a protrusion 15a opposite to the bottom surface 14a of the cooling cylinder 14, which is opposite to the raw material molten material, and the flange portion 16 of the cooling auxiliary cylinder 13.

[0079] from Figure 2 The cylindrical portion of the flange portion 16 of the cooling auxiliary cylinder 13, extending toward the raw material melt, is composed of a first cylindrical portion 19 for rectifying the flow and a second cylindrical portion 20 for fixing the auxiliary component 15 and the cooling auxiliary cylinder 13 together. The first cylindrical portion 19 and the second cylindrical portion 20 can be formed with a groove portion 21 between them. At this time, as Figure 4 , 5 As shown, the cooling auxiliary cylinder 13 may also have a structure that does not form the second cylindrical portion 20.

[0080] For the bonding auxiliary component 15, by extending the arc portion 15b to a position higher than the protrusion 15a, the bonding auxiliary component 15 is brought close to the outer surface of the cooling cylinder 14 which is forcibly cooled by the cooling medium, and the bonding auxiliary component 15 is effectively cooled. By cooling the bonding auxiliary component 15, heat from the single crystal 6 can be effectively dissipated.

[0081] Regarding the shape of the fitting auxiliary component 15, it has a protrusion 15a and arcuate portions 15b and 15c extending to the upper and lower sides of the protrusion 15a. The arcuate portions 15b and 15c on the upper and lower sides of the protrusion 15a are concentric circles with the outer periphery of the cooling cylinder 14 and the cooling auxiliary cylinder 13. The protrusion 15a is opposite to the bottom surface 14a of the cooling cylinder 14 that is opposite to the raw material melt and the flange portion 16 of the cooling auxiliary cylinder 13. The surface 15d of the protrusion 15a of the fitting auxiliary component 15, which contacts the flange 16 of the cooling auxiliary cylinder 13, is tapered. By pressing the protrusion 15a of the fitting auxiliary component 15 between the bottom surface 14a of the cooling cylinder 14 and the flange 16 of the cooling auxiliary cylinder 13, the bottom surface 14a of the cooling cylinder 14 and the protrusion 15a of the fitting auxiliary component 15 are brought into close contact, and the protrusion 15a of the fitting auxiliary component 15 and the flange 16 of the cooling auxiliary cylinder 13 are brought into close contact. By setting the taper, even if there are dimensional tolerances between the cooling cylinder 14 and the cooling auxiliary cylinder 13, they can be firmly pressed together by pressing in the protrusion 15a of the fitting auxiliary component 15. At this time, the taper angle of the tapered surface 15d of the protrusion 15a of the fitting auxiliary component 15 is preferably 5~25°. The pressing amount of the fitting auxiliary component 15 is determined by the cone angle. However, if the cone angle is too small, the pressing amount becomes large, making it difficult to ensure a sufficient gap between the outer circumferential surface of the cooling cylinder 14 and the inner circumferential surface of the fitting auxiliary component 15. Therefore, the cone angle is preferably 5° or greater. A larger cone angle results in a smaller pressing amount of the fitting auxiliary component 15, but increases the weight of the fitting auxiliary component 15 and makes the support and fixing operations provided by the bolts more difficult. Therefore, the cone angle is preferably 25° or less. Figure 4 , 5 As shown, if the cone angle is such, the close-fitting auxiliary component 15 can be supported / fixed even if the second cylindrical portion 20 is not formed on the cooling auxiliary cylinder 13.

[0082] Prepare multiple adhesive support components 15, and press the protrusions 15a of the adhesive support components 15 all around the circumference into the gap between the flange of the cooling auxiliary cylinder 13 and the bottom surface 14a of the cooling cylinder 14. Thus, in addition to the inner surface of the cooling cylinder 14, the bottom surface 14a of the cooling cylinder 14 can also be pressed against the cooling auxiliary cylinder 13 through the adhesive support components 15. To press the adhesive support components 15 into the gap between the bottom surface 14a of the cooling cylinder 14 and the flange 16 of the cooling auxiliary cylinder 13, the adhesive support components 15 can be segmented, such as divided into three or four equal parts; there can be more or fewer of these segments.

[0083] The single crystal manufacturing apparatus 200 also has a diameter enlargement component 17 that fits into the cooling auxiliary cylinder 13.

[0084] Figure 3This is a perspective view showing the diameter enlargement component 17 and the cooling auxiliary cylinder 13. The cooling auxiliary cylinder 13 has a slit 13a extending along the axial direction A, and the diameter enlargement component 17 fits into the inner surface of the cooling auxiliary cylinder 13.

[0085] The cooling auxiliary cylinder 13 is pressed into the inner surface of the cooling cylinder 14 by the diameter enlargement component 17.

[0086] In order to effectively absorb the radiant heat from the single crystal 6 and effectively transfer the heat to the cooling cylinder 14, the cooling auxiliary cylinder 13 and the bonding auxiliary component 15 of the present invention are preferably made of graphite, carbon composite material, stainless steel, molybdenum, and tungsten. Among the above materials, graphite, which has a thermal conductivity equal to or greater than that of metal and an emissivity higher than that of metal, is particularly preferred.

[0087] The auxiliary component 15 is fitted by pressing its protrusion 15a between the bottom surface 14a of the cooling cylinder and the flange 16 of the cooling auxiliary cylinder. To ensure a more secure press-in and fit, and to prevent it from falling off, for example... Figure 2 As shown, preferably, a threaded hole 23 is provided on the outer peripheral surface of the second cylindrical portion 20 located on the outer periphery of the cylindrical portion extending from the flange portion 16 towards the raw material melt in the cooling auxiliary cylinder 13. A through hole 15e is provided in the fitting auxiliary component 15 at a position corresponding to the threaded hole 23, and fastened by a fixing bolt 18. Thus, the cooling auxiliary cylinder 13 and the fitting auxiliary component 15 are fastened and fixed by the fixing bolt 18, which passes through the through hole 15e and is screwed into the threaded hole 23. At this time, for a more secure fit, it is preferable to use a hex wrench to tighten the bolt. In addition, in Figure 2 In the diagram, dashed leader lines indicate the locations of threaded holes 23 and through holes 15e.

[0088] Since the furnace is at high temperature during operation and is subject to radiation from furnace components, the material of the fixing bolt 18 of the present invention is preferably any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

[0089] In addition, a heat shielding component 22, made of graphite material, is suspended and fixed on a component, such as one made of SUS, installed on the upper inner surface of the main chamber 1.

[0090] A gas inlet 11 for introducing an atmosphere gas (e.g., Ar gas) is provided on the pulling chamber 7, and a gas outlet 12 for discharging the introduced atmosphere gas is provided at the bottom of the main chamber 1. While introducing the atmosphere gas through the gas inlet 11, the seed crystal 8 mounted on the seed holder 9 is immersed in the raw material melt 5, and the pulling wire 10 is rotated and wound up, thereby pulling the single crystal 6.

[0091] [Example]

[0092] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited thereto.

[0093] (Example 1)

[0094] Use such as Figure 4 and Figure 5 The single crystal manufacturing apparatus 300 shown was used for single crystal manufacturing. The following section discusses its application in conjunction with... Figure 1 and Figure 2 The description of the same components as those in the single crystal manufacturing apparatus 200 is omitted as appropriate.

[0095] The cooling cylinder 14 and the cooling auxiliary cylinder 13 are tightly attached together by a diameter-enlarging member 17. Furthermore, a fastening auxiliary member 15 is screwed into the gap between the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13. Additionally, the cooling auxiliary cylinder 13 and the fastening auxiliary member 15 are made of graphite, a material with thermal conductivity equal to or higher than that of metal and an emissivity higher than that of metal.

[0096] To accommodate the diameter-enlarged component 17, the cooling auxiliary cylinder 13 is designed as a tapered shape with an inner diameter that increases towards the top, and the tapered angle is 10.5°. Furthermore, a radially extending flange portion 16 is provided on the cooling auxiliary cylinder 13. Additionally, a first cylindrical portion 19 extends downward from the flange portion 16 toward the raw material melt.

[0097] The diameter enlargement component 17, like the cooling auxiliary cylinder 13, is designed as a cone with a larger outer diameter towards the top, and the cone angle is 10.5°.

[0098] Regarding the shape of the fitting auxiliary component 15, it has a protrusion 15a and arcuate portions 15b and 15c extending to the upper and lower sides of the protrusion 15a, respectively. The arcuate portions 15b and 15c are concentric circles with the outer periphery of the cooling cylinder 14 and the cooling auxiliary cylinder 13. The protrusion 15a is opposite to the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13, which are opposite to the raw material melt 5. The surface 15d of the protrusion 15a of the fitting auxiliary component 15 that contacts the flange portion 16 of the cooling auxiliary cylinder 13 is conical with a cone angle of 10°.

[0099] To press the fitting auxiliary member 15 into the gap between the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13, the fitting auxiliary member 15 is in a four-part shape. The inner surface of the cooling cylinder 14 is brought into contact with the outer surface of the cooling auxiliary cylinder 13 by pressing the diameter-enlarging member 17 into the inner surface of the cooling auxiliary cylinder 13. Furthermore, the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13 are brought into contact through the fitting auxiliary member 15. Then, the heat shielding member 22, made of graphite material, is installed and fixed on an SUS-made component mounted on the upper inner surface of the main chamber 1 in the form of a suspended heat shielding member 22.

[0100] Using such a single-crystal fabrication apparatus 300, single-crystal silicon with a diameter of 300 mm was grown, and the growth rate that would result in a completely defect-free crystal was determined. Since the margin for the growth rate used to obtain a defect-free crystal is very narrow, it is easy to determine the appropriate growth rate. Regarding the evaluation of whether a single crystal is defect-free, a sample is cut from the fabricated single crystal, and selective etching is used to evaluate whether it becomes a defect-free region.

[0101] (Example 2)

[0102] use Figure 1 and Figure 2 The single crystal manufacturing apparatus 200 shown was used for single crystal manufacturing.

[0103] The cooling cylinder 14 and the cooling auxiliary cylinder 13 are tightly attached together by a diameter-enlarging member 17. Furthermore, a fastening auxiliary member 15 is screwed into the gap between the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13. Additionally, the cooling auxiliary cylinder 13 and the fastening auxiliary member 15 are made of graphite, a material with thermal conductivity equal to or higher than that of metal and an emissivity higher than that of metal.

[0104] In order to fit the diameter-enlarged component 17, the cooling auxiliary cylinder 13 is designed as a tapered shape with the inner diameter increasing towards the top, and the tapered angle is 10.5°.

[0105] Furthermore, a radially extending flange portion 16 is provided on the cooling auxiliary cylinder 13. In addition, a first cylindrical portion 19 and a second cylindrical portion 20 extending downward from the flange portion 16 in the direction of the raw material melt are provided, with the first cylindrical portion 19 on the inner circumferential side and the second cylindrical portion 20 on the outer circumferential side formed with a groove portion 21 between them.

[0106] At positions 30 mm and 86.5 mm from the lower end of the second cylindrical portion 20 of the cooling auxiliary cylinder 13, 36 threaded holes 23 with a depth of 10 mm are evenly distributed at 20° in the circumferential direction.

[0107] The diameter-enlarging component 17, like the cooling auxiliary cylinder 13, is a cone shape with its outer diameter increasing towards the top, and the cone angle is 10.5°. The fitting auxiliary component 15 has a protrusion 15a and arcuate portions 15b and 15c extending towards the upper and lower sides of the protrusion 15a, respectively. The arcuate portions 15b and 15c are concentric circles with the outer peripheries of the cooling cylinder 14 and the cooling auxiliary cylinder 13. The protrusion 15a is opposite to the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13, which are opposite to the raw material melt 5. The surface 15d of the protrusion 15a of the fitting auxiliary component 15 that contacts the flange portion 16 of the cooling auxiliary cylinder 13 is conical with a cone angle of 10°. On the arc portion 15c that is attached to the auxiliary component 15, in order to thread and fix the cooling auxiliary cylinder 13, a total of 36 through holes 15e are provided at positions 88mm and 144.5mm from the lower end, evenly distributed at a circumferential angle of 20°.

[0108] After pressing the protrusion 15a of the auxiliary component 15 between the bottom surface 14a of the cooling cylinder and the flange 16 of the cooling auxiliary cylinder, the fixing bolt 18 passes through the through hole 15e. Then, by screwing the fixing bolt 18 into the threaded hole 23, the cooling auxiliary cylinder 13 and the auxiliary component 15 are fastened and fixed by the fixing bolt 18.

[0109] To press the fitting auxiliary component 15 into the gap between the cooling cylinder 14 and the cooling auxiliary cylinder 13, the fitting auxiliary component 15 is in a four-part shape. The fixing bolts 18 are made of a high-strength carbon composite material that can withstand the high-temperature furnace environment. By pressing the diameter-enlarging component 17 into the inner surface of the cooling auxiliary cylinder 13, the inner surface of the cooling cylinder 14 is brought into contact with the outer surface of the cooling auxiliary cylinder 13. In addition, the bottom surface 14a of the cooling cylinder 14 and the flange portion 16 of the cooling auxiliary cylinder 13 are brought into contact through the fitting auxiliary component 15. To more reliably prevent the fitting auxiliary component 15 from falling off during operation, the fixing bolts 18 are screwed into the threaded holes 23 to fix the fitting auxiliary component 15. Afterwards, the heat shield component 22 is installed and fixed on the upper inner surface of the main chamber 1 by suspending a heat shield component 22 made of graphite material.

[0110] Single crystal fabrication was performed using this apparatus. All other conditions were the same as those described in Example 1.

[0111] (Comparative Example 1)

[0112] Single crystal manufacturing was performed using the same apparatus as the single crystal manufacturing apparatus 300 described in Example 1, except that the cooling auxiliary cylinder 13, the bonding auxiliary component 15, and the diameter enlargement component 17 were not used. All other conditions were the same as those described in Example 1. Figure 6The single crystal manufacturing apparatus 400 used in Comparative Example 1 is shown schematically. Additionally, in Figure 6 In the text, only the cooling cylinder 14 is marked with a reference symbol.

[0113] (Comparative Example 2)

[0114] Single crystal manufacturing was performed using the same apparatus as the single crystal manufacturing apparatus 300 described in Example 1, except that the bonding auxiliary component 15 was not used. All other conditions were the same as those described in Example 1. Figure 7 The single crystal manufacturing apparatus 500 used in Comparative Example 2 is shown schematically. Additionally, in Figure 7 In the text, only the cooling auxiliary cylinder 13, the flange portion 16 of the cooling auxiliary cylinder 13, the diameter enlargement component 17, and the cooling cylinder 14 are marked with reference symbols.

[0115] The results of Examples 1 and 2, as well as Comparative Examples 1 and 2, are shown in Table 1.

[0116] Table 1

[0117]

[0118] It has been confirmed that in Example 1, which used the single crystal manufacturing apparatus 300 of the present invention, and Figure 6 Compared to Comparative Example 1, which did not use a cooling auxiliary cylinder and had the auxiliary components in close contact, a 20.0% increase in crystal growth rate was achieved. Figure 7 Compared to Comparative Example 2 without the use of the bonding auxiliary component, a crystal growth rate of 12.1% was achieved.

[0119] Furthermore, it was confirmed that in Example 2, which used the single crystal manufacturing apparatus 200 of the present invention, the relationship with... Figure 6 Compared to Comparative Example 1, which did not use a cooling auxiliary cylinder and had the auxiliary components in close contact, a 21.0% increase in crystal growth rate was achieved. Figure 7 Compared to Comparative Example 2 without the use of the bonding auxiliary component, a crystal growth rate of 13.1% was achieved.

[0120] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are illustrative examples, and any solution having a substantially the same structure and producing the same effect as the technical concept described in the claims of the present invention is included within the technical scope of the present invention.

Claims

1. A single crystal manufacturing apparatus for growing single crystals using the Czeklaussky process, the apparatus comprising: a main chamber housing a crucible containing molten raw material and a heater for heating the molten raw material; a pulling chamber connected to the upper part of the main chamber for pulling and housing the grown single crystal; and a cooling cylinder extending from at least the top of the main chamber toward the surface of the molten raw material in a manner surrounding the pulled single crystal, and being forcibly cooled by a cooling medium. Its features are, It also includes a cooling auxiliary cylinder fitted inside the cooling cylinder and a diameter-enlarging component fitted inside the cooling auxiliary cylinder. The cooling auxiliary cylinder has a slit that runs through the entire axial direction. The cooling auxiliary cylinder is pressed into place against the inner surface of the cooling cylinder by the enlarging diameter component. The cooling auxiliary cylinder has a flange that extends outward to cover the bottom surface of the cooling cylinder opposite to the raw material molten liquid. By using a fastening auxiliary component that fits between the flange of the cooling auxiliary cylinder and the bottom surface of the cooling cylinder, the bottom surface of the cooling cylinder, the fastening auxiliary component, and the flange of the cooling auxiliary cylinder are brought into close contact.

2. The single crystal manufacturing apparatus according to claim 1, characterized in that, The material of the cooling auxiliary cylinder is any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

3. The single crystal manufacturing apparatus according to claim 1, characterized in that, The material of the adhesive auxiliary component is any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

4. The single crystal manufacturing apparatus according to claim 2, characterized in that, The material of the adhesive auxiliary component is any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

5. The single crystal manufacturing apparatus according to claim 1, characterized in that, The bonding auxiliary component has: a protrusion that faces the bottom surface of the cooling cylinder opposite to the raw material melt and the flange of the cooling auxiliary cylinder; and an arcuate portion that extends above and below the protrusion. The arc-shaped portion is concentric with the outer periphery of the cooling cylinder and the cooling auxiliary cylinder. The surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is tapered.

6. The single crystal manufacturing apparatus according to claim 2, characterized in that, The bonding auxiliary component has: a protrusion that faces the bottom surface of the cooling cylinder opposite to the raw material melt and the flange of the cooling auxiliary cylinder; and an arcuate portion that extends above and below the protrusion. The arc-shaped portion is concentric with the outer periphery of the cooling cylinder and the cooling auxiliary cylinder. The surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is tapered.

7. The single crystal manufacturing apparatus according to claim 3, characterized in that, The bonding auxiliary component has: a protrusion that faces the bottom surface of the cooling cylinder opposite to the raw material melt and the flange of the cooling auxiliary cylinder; and an arcuate portion that extends above and below the protrusion. The arc-shaped portion is concentric with the outer periphery of the cooling cylinder and the cooling auxiliary cylinder. The surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is tapered.

8. The single crystal manufacturing apparatus according to claim 4, characterized in that, The bonding auxiliary component has: a protrusion that faces the bottom surface of the cooling cylinder opposite to the raw material melt and the flange of the cooling auxiliary cylinder; and an arcuate portion that extends above and below the protrusion. The arc-shaped portion is concentric with the outer periphery of the cooling cylinder and the cooling auxiliary cylinder. The surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is tapered.

9. The single crystal manufacturing apparatus according to claim 5, characterized in that, The cone angle of the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is 5 to 25°.

10. The single crystal manufacturing apparatus according to claim 6, characterized in that, The cone angle of the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is 5 to 25°.

11. The single crystal manufacturing apparatus according to claim 7, characterized in that, The cone angle of the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is 5 to 25°.

12. The single crystal manufacturing apparatus according to claim 8, characterized in that, The cone angle of the surface of the protrusion of the fitting auxiliary component that contacts the flange of the cooling auxiliary cylinder is 5 to 25°.

13. The single crystal manufacturing apparatus according to any one of claims 1 to 12, characterized in that, On the inner and outer peripheries of the flange portion of the cooling auxiliary cylinder, a first cylindrical portion and a second cylindrical portion are formed downwardly, separated by a groove portion. A threaded hole is provided on the outer peripheral surface of the second cylindrical portion on the outer peripheral side. The fitting auxiliary component has a through hole at a position corresponding to the threaded hole in the second cylindrical portion of the cooling auxiliary cylinder. The cooling auxiliary cylinder and the bonding auxiliary component are fastened and fixed by bolts that pass through the through hole and are screwed into the threaded hole.

14. The single crystal manufacturing apparatus according to claim 13, characterized in that, The bolt is made of any one of graphite, carbon composite material, stainless steel, molybdenum, and tungsten.

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