JP2012116691A - Melting apparatus of single crystal raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting apparatus of a single crystal raw material, with which the single crystal raw material supplied in a crucible can be directly heated from the upper side of the crucible, while suppressing complication of a structure of a main chamber and increase in the equipment cost.SOLUTION: The melting apparatus of a single crystal raw material includes: a body which has a moving mechanism; a cylindrical body which has a lower open end linked to a gate valve of a main chamber of a single crystal production apparatus and an upper closing end; a cylindrical body lifting mechanism which is provided on the body and which makes the cylindrical body go up and down between a linking position with which the lower open end and the gate valve are linked to each other and a release position in which the lower open end and the gate valve are vertically separated; a heater which projects from the inside of the cylindrical body to the lower side and with which a single crystal raw material in the crucible is heated; a heater lifting mechanism which is provided on the body and which makes the heater go up and down between a holding position in the cylindrical body and a single crystal raw material heating position on the lower side from the lower open end; and a connection part to a power supply source which supplies electric power to the heater.

Description

  The present invention relates to a single crystal raw material melting apparatus, and more particularly, to a single crystal raw material melting apparatus used when a single crystal ingot is manufactured by the Czochralski method.

  Conventionally, the Czochralski method (CZ method) is known as a method for producing various single crystal ingots such as silicon single crystal and sapphire single crystal.

  Then, the manufacture of the single crystal ingot by the Czochralski method was installed so as to be able to communicate with the main chamber 410 via the gate valve 411 on the main chamber 410 and the main chamber 410 as shown in FIG. This is performed using a single crystal manufacturing apparatus 400 including a pull chamber 420. Specifically, in the manufacture of the single crystal ingot 423 by the Czochralski method, a single crystal raw material is put into a crucible 412 disposed in the main chamber 410, and the single crystal raw material in the crucible 412 is heated by a heater 413. And melted into a single crystal raw material melt 414, and then contacted with the single crystal raw material melt 414 in the crucible 412 the seed crystal 422 attached to the tip of the wire rope 421 disposed in the pull chamber 420. This is done by pulling up the seed crystal 422 while rotating it. In this single crystal manufacturing apparatus 400, a heat insulating cylinder 415 is disposed on the outer peripheral side of the heater 413 inside the main chamber 410, and a heat insulating material 416 is disposed below the inside of the main chamber 410. Yes.

  Here, in the conventional single crystal manufacturing apparatus, the single crystal raw material in the crucible is melted using a heater disposed around the crucible, and the single crystal raw material is passed through the crucible when the single crystal raw material is melted. It needs to be heated. For this reason, the time required for melting the single crystal raw material becomes longer, and depending on the material of the crucible, the crucible becomes deteriorated due to high temperature (for example, quartz becomes cristobalite in the case of a quartz crucible), and the crystal pulled up It may be dislocated.

  The problems of the melting time of the single crystal raw material and the crucible deterioration as described above are caused by the production of a large-diameter single crystal ingot that requires melting of a large amount of single crystal raw material (for example, a single crystal having a diameter of 300 mm or more, particularly 400 mm or more in diameter). In the production of crystalline silicon ingots, etc.).

  Therefore, the single crystal raw material in the crucible is directly heated above the crucible in the main chamber as a single crystal manufacturing apparatus capable of reducing the time required for melting the single crystal raw material and suppressing the deterioration of the crucible. There has been proposed a single crystal manufacturing apparatus further provided with a sub-heater that can be used (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 9-241944 Japanese Patent No. 29987799

  However, in the conventional single crystal manufacturing apparatus in which the sub heater is provided above the crucible in the main chamber, the structure in the main chamber becomes complicated, and a sub heater must be provided for each main chamber. In the case where a single crystal ingot is mass-produced using a plurality of main chambers, there is a problem that the equipment cost increases.

  Accordingly, the present invention provides a single crystal raw material melting apparatus capable of directly heating a single crystal raw material charged into a crucible from above the crucible while suppressing the complexity of the structure of the main chamber and the increase in equipment cost. The purpose is to do.

  The present invention aims to advantageously solve the above-mentioned problems, and the single crystal raw material melting apparatus of the present invention was put into a crucible in a main chamber of a single crystal manufacturing apparatus by the Czochralski method. A melting apparatus used for melting a single crystal raw material, a cylindrical body having a main body having a moving mechanism, a lower opening end connected to a gate valve of a main chamber of the single crystal manufacturing apparatus, and an upper closed end The cylindrical body is moved up and down between a connection position provided in the main body portion, where the lower opening end and the gate valve are connected, and a release position where the lower opening end and the gate valve are vertically separated. A cylindrical body elevating mechanism that moves up and down, a heater that heats the single crystal raw material in the crucible protruding downward from the inside of the cylindrical body, the main body portion, the accommodation position in the cylindrical body, beneath A heater elevating mechanism for elevating the heater up and down between the single crystal raw material heating position below the mouth end, characterized in that it comprises a connection portion of a power supply source for supplying power to the heater. Thus, if the main body is provided with a moving mechanism so that the melting apparatus can be moved, a single melting apparatus can be shared among a plurality of main chambers, so a sub-heater is provided for each main chamber. The increase in equipment cost can be suppressed compared to the case. Further, if a cylindrical body, a cylindrical body lifting mechanism, a heater, and a heater lifting mechanism are provided, a sub heater is not provided in the main chamber, that is, without complicating the structure in the main chamber, The single crystal raw material in the crucible of the main chamber can be directly heated from above the crucible.

  Here, in the apparatus for melting a single crystal raw material of the present invention, the cylindrical body has a bellows structure, the heater is fixed to the upper closed end, and the heater elevating mechanism includes the cylinder It is preferable that the heater is moved up and down by expanding and contracting the shape. If a cylindrical body having a bellows structure is used and the heater elevating mechanism elevates and lowers the heater by expanding and contracting the cylindrical body, the apparatus can be downsized and the burden when moving the apparatus can be reduced. It is.

  In addition, the single crystal raw material melting apparatus of the present invention preferably includes a pressurizing unit that pressurizes the inside of the cylindrical body when the connection between the lower opening end of the cylindrical body and the gate valve is released. If a pressurizing means is provided, even if the single crystal raw material is melted after setting the atmosphere in the chamber to a reduced pressure atmosphere or a vacuum atmosphere and then the gate valve is closed, the inside of the cylindrical body is pressurized to This is because the connection between the lower opening end of the shaped body and the gate valve can be easily released.

  Furthermore, the single crystal raw material melting apparatus of the present invention preferably includes a gas supply means for supplying a gas into the cylindrical body. This is because if the gas supply means is provided, gas can flow from the cylindrical body side into the chamber when the single crystal raw material is melted.

  Moreover, it is preferable that the single crystal raw material melting apparatus of the present invention further includes a heat shield that moves integrally with the heater above the heater. If a heat shield is provided, heat dissipation from the heater upward (cylindrical body side) can be suppressed, and the single crystal raw material can be heated more efficiently by the heater, and the cylindrical body can be heated by the heat from the heater. This is because deterioration can be prevented.

  The single crystal raw material melting apparatus of the present invention has a heater position control mechanism that detects the position of the single crystal raw material in the crucible and controls the vertical position of the heater according to the position of the single crystal raw material. It is preferable. If the heater position control mechanism is provided, the bulk density of the single crystal raw material in the crucible becomes higher due to the melting of part of the single crystal raw material, and the position of the heater can be adjusted even if the position of the single crystal raw material in the crucible changes. This is because the single crystal raw material can be efficiently heated by adjustment.

  According to the single crystal raw material melting apparatus of the present invention, the single crystal raw material charged into the crucible can be directly heated from above the crucible while suppressing the complexity of the structure of the main chamber and the increase in equipment cost.

It is explanatory drawing which shows the structure of the melting apparatus of the typical single crystal material according to this invention. It is a perspective view which expands and shows the vicinity of the heater and heat shield of the melting apparatus shown in FIG. It is explanatory drawing which shows the process until a single crystal raw material is fuse | melted using the melting apparatus shown in FIG. 1, (a) shows the process of moving a melting apparatus to the main chamber vicinity of a single crystal manufacturing apparatus, (b) Indicates a step of connecting the gate valve of the main chamber of the single crystal manufacturing apparatus and the cylindrical body of the melting apparatus. It is explanatory drawing which shows the process until a single crystal raw material is fuse | melted using the melting apparatus shown in FIG. 1, (a) shows the process of lowering a heater to a single crystal raw material heating position, (b) is a single crystal raw material The process of melting is shown. It is explanatory drawing which shows the process until it starts the pulling of a single crystal after melting a single crystal raw material using the melting apparatus shown in FIG. 1, (a) shows the process of raising a heater to an accommodation position, (b ) Shows a step of releasing the connection between the gate valve of the main chamber of the single crystal manufacturing apparatus and the cylindrical body of the melting apparatus. It is explanatory drawing which shows the process until it starts pulling up of a single crystal, after melting a single crystal raw material using the melting apparatus shown in FIG. 1, (a) shows the process of moving a melting apparatus, (b) A process of starting pulling of a single crystal by connecting a pull chamber to the main chamber of the single crystal manufacturing apparatus is shown. It is explanatory drawing which shows the structure of the conventional single crystal manufacturing apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. The single crystal raw material melting apparatus of the present invention is charged into a crucible in a main chamber of a single crystal manufacturing apparatus when manufacturing ingots of various single crystals such as silicon single crystals and sapphire single crystals using the Czochralski method. Used to melt the single crystal raw material. The single crystal raw material melting apparatus of the present invention has a moving mechanism and is configured to be movable between a plurality of main chambers.

  Here, FIG. 1 shows a structure of an example of a single crystal raw material melting apparatus of the present invention. A single crystal raw material melting apparatus 100 shown in FIG. 1 includes a main body portion 1 having a wheel 11 at a lower portion, a support plate lifting device 3 provided on the upper portion of the main body portion 1, and a main body portion via the support plate lifting device 3. 1 is provided with a support plate 12 extending in the left direction in FIG. 1, and a cylindrical body 2 and a guide column 13 provided on the support plate 12 at a position offset from the main body 1. Yes. Further, a control device 9 that controls the operation of each part of the melting device 100 is provided inside the main body 1 of the melting device 100. Furthermore, inside the cylindrical body 2 of the melting apparatus 100, when the single crystal raw material is melted using the melting apparatus 100, a heater 4 that protrudes downward from the inside of the cylindrical body 2 and heats the single crystal raw material, A heat shield 6 disposed above the heater 4 is provided. In addition, the melting apparatus 100 includes heater power lines 61 a and 61 b and a water-cooled electrode 62 a that transmit part of the power supplied from the outside of the melting apparatus 100 to the heater 4 through the power plug 7 disposed in the main body 1. 62 b, a cooling water line (not shown) for supplying cooling water supplied from the outside of the melting apparatus 100 to the water cooling electrodes 62 a and 62 b via the cooling water supply port 64 disposed in the main body 1, and the main body And a gas line 8 for introducing a gas supplied from the outside of the melting apparatus 100 through the gas supply port 81 provided in the section 1 into the cylindrical body 2.

  The wheel 11 provided in the lower part of the main body 1 functions as a moving mechanism when the melting apparatus 100 is moved. The melting apparatus 100 can easily move between a plurality of main chambers using the wheels 11.

  The cylindrical body 2 is connected to the main body 1 via a support plate 12 and a support plate lifting device 3. Moreover, the cylindrical body 2 has a bellows structure made of, for example, stainless steel, and is configured to be extendable in the vertical direction in FIG. The lower portion of the cylindrical body 2 (on the support plate 12 side) is a lower opening end 21 that passes through the support plate 12 and opens downward. The lower opening end 21 is simply formed using the melting device 100. When the crystal raw material is melted, it is connected to the gate valve of the main chamber of the single crystal manufacturing apparatus. The upper portion of the cylindrical body 2 is an upper closed end that is airtightly closed by a closing plate 22, and the closing plate 22 is connected to a closing plate lifting device 5 provided on the guide column 13. .

  Here, the support plate lifting / lowering device 3 is provided in the main body 1 and moves the support plate 12 supporting the cylindrical body 2, the guide column 13 and the like up and down in FIG. The support plate lifting / lowering device 3 moves the support plate 12 up and down using a motor or the like (not shown) provided in the main body 1, so that the cylindrical body 2 is moved into a cylinder when the single crystal raw material is melted. Between the connection position where the lower opening end 21 of the cylindrical body 2 and the gate valve of the main chamber of the single crystal manufacturing apparatus are connected, and the release position where the lower opening end 21 of the cylindrical body 2 and the gate valve are vertically separated It functions as a cylindrical body lifting mechanism that moves up and down.

  Further, the closing plate elevating device 5 is provided integrally with the main body 1 via the guide column 13, the support plate 12 and the support plate elevating device 3, and the closing plate 22 is moved up and down along the guide column 13 in FIG. It moves up and down in the direction. And this closing plate raising / lowering device 5 has a bellows structure where the lower part was fixed to the support plate 12 by moving the closing plate 22 up and down along the guide column 13 using a motor or the like (not shown). The cylindrical body 2 can be expanded and contracted in the vertical direction.

  Here, water-cooling electrodes 62 a and 62 b are inserted into the closing plate 22 in an airtight manner, and the quartz plate 63, the heat shield 6, and the heater 4 are disposed at the tips of the water-cooling electrodes 62 a and 62 b (lower side in FIG. 1). Is provided. Specifically, as shown in the enlarged view of the vicinity of the heater 4 and the heat shield 6 in FIG. 2, the quartz plate 63 is formed at the tip of the water-cooled electrodes 62a and 62b, and the graphite is formed at the tips of the water-cooled electrodes 62a and 62b. And a heat shield 6 comprising two heat shield plates fixed to the quartz plate 63 between the quartz plate 63 and the heater 4. That is, the heater 4, the heat shield 6, and the quartz plate 63 provided at the tips of the water-cooled electrodes 62 a and 62 b that pass through the closing plate 22 in an airtight manner with respect to the closing plate 22 that is the upper closed end of the cylindrical body 2. It is fixed. In addition, as a heat shielding board, what covered the plate-shaped heat insulating material with the graphite material can be used. Moreover, as the water-cooled electrodes 62a and 62b, for example, electrodes having a hollow double tube structure and capable of flowing cooling water therein can be used.

  Therefore, when the closing plate lifting and lowering device 5 moves the closing plate 22 up and down (up and down movement) along the guide column 13, the cylindrical body 2 expands and contracts, and the heater 4 and the heat shield as the closing plate 22 moves up and down. The body 6 and the quartz plate 63 also move up and down integrally. Therefore, the closing plate lifting / lowering device 5 moves the heater 4 into the accommodation position in the cylindrical body 2 and the single crystal raw material heating position below the lower opening end 21 of the cylindrical body 2 (when the single crystal raw material is melted, the heater 4 It functions as a heater elevating mechanism that moves up and down between the single crystal raw material and the position where the single crystal raw material is heated.

  The main body 1 of the melting apparatus 100 is provided with a power plug 7, a cooling water supply port 64, and a gas supply port 81. The power plug 7, the cooling water supply port 64, and the gas supply port 81 are each pulled out from the main body 1 and provided with an external power source (external power supply source) provided in a factory or the like where the melting apparatus 100 is used. It can be connected to a water source and a gas source. In addition, the electric power supplied from the external power supply through the power plug 7 which is a connection part with the external power supply passes through the main body 1 and the heater power lines 61a and 61b extending to the water cooling electrodes 62a and 62b. 4 is used for heating the support plate lifting device 3, the closing plate lifting device 5, and the control device 9 in the main body 1. Further, the cooling water supplied from the cooling water supply port 64 is supplied to the water cooling electrodes 62a and 62b through a cooling water line (not shown) extending through the main body 1 to the water cooling electrodes 62a and 62b. . Further, the gas supplied from the gas supply port 81 passes through the main body portion 1 and protrudes onto the support plate 12 and the main body side outlet 82 and the cylindrical body side inlet through which the closing plate 22 of the cylindrical body 2 is inserted in an airtight manner. The gas is supplied into the cylindrical body 2 through a flexible gas line 8 provided between the cylinder 83.

  The gas supply port 81 and the gas line 8 for supplying gas into the cylindrical body 2 supply gas into the main chamber via the cylindrical body 2 when the single crystal raw material is melted. Can be used as a gas supply means for controlling the atmosphere of the cylindrical body 2 and the lower opening end 21 of the cylindrical body 2 and the gate valve of the main chamber after melting the single crystal raw material in a reduced pressure atmosphere or a vacuum atmosphere. It can be used as a pressurizing means for pressurizing the inside of the cylindrical body 2 when releasing the connection with.

  Furthermore, a control device 9 such as a computer is provided inside the main body 1 of the melting device 100. In the melting apparatus 100, the control device 9 controls operations of the support plate elevating device 3, the heater 4, the closing plate elevating device 5, and the like.

  If the single crystal raw material melting apparatus 100 of the above example is used, the crucible in the main chamber of the single crystal manufacturing apparatus is used as described below with reference to FIGS. 3A, 3B, 4A, and 4B, for example. The supplied single crystal raw material can be melted to produce a single crystal.

  Here, as a single crystal manufacturing apparatus to which the melting apparatus 100 is applied, as shown in FIGS. 3A to 4B, a main chamber 200 having a crucible 210 disposed therein, a pull chamber 300 having a single crystal pulling mechanism, and A pull chamber swivel raising / lowering device 330 for swiveling and raising / lowering the pull chamber 300 between the gate valve 280 provided in the upper opening of the main chamber 200 and the left side of the main chamber 200 in FIGS. 3A to 4B is provided. An apparatus can be mentioned.

  The main chamber 200 includes a crucible 210 composed of a quartz crucible 210 a for accommodating the single crystal raw material 220 and a graphite crucible 210 b for supporting the quartz crucible 210 a, and a crucible 210 disposed around the crucible 210. A side heater 230 for heating the single crystal raw material 220 and a crucible rotating mechanism 211 for rotating the crucible 210 provided under the crucible 210 in the circumferential direction, for example, are provided. A heat insulating cylinder 240 is disposed on the outer peripheral side of the side heater 230 inside the main chamber 200, and a heat insulating material 250 is disposed below the inside of the main chamber 200. Further, a rectifying cylinder 260 is arranged above the crucible 210 in the main chamber 200 for adjusting the flow of gas flowing into the main chamber when the single crystal raw material 220 is melted or when the single crystal is pulled up. The main chamber 200 may optionally be provided with a lower heater that heats the single crystal raw material 220 in the crucible 210 from below the crucible 210. The main chamber 200 may optionally be provided with a known raw material charging device for additionally charging the single crystal raw material 220 into the crucible 210.

  The pull chamber 300 includes a wire rope 310 to which a seed crystal 311 for growing a single crystal is attached at the tip, and a single crystal grown on the seed crystal 311 and the seed crystal 311 by winding the wire rope 310. A pulling mechanism 321 for pulling up the wire, and rotating the pulling mechanism 321 in a direction opposite to the rotation direction of the crucible 210, so that the wire rope 310, the seed crystal 311 and the single crystal grown on the seed crystal 311 are opposite to the crucible 210. And a rotating mechanism 320 that rotates in the direction.

  And the melting of the single crystal raw material 220 in the main chamber 200 using the melting apparatus 100 is performed as follows, for example.

  First, as shown in FIG. 3A (a), the melting apparatus 100 is moved to a predetermined position using the wheels 11, and as shown in FIG. 3A (b), the main chamber 200 for melting the single crystal raw material 220 is obtained. The lower open end 21 of the cylindrical body 2 of the melting apparatus 100 is positioned above the gate valve 280.

  Next, as shown in FIG. 3A (b), the power plug 7, the cooling water supply port 64, and the gas supply port 81 are pulled out from the main body 1, and the external power source P (external power supply source) and the cooling water supply source W are extracted. And a gas supply source G. And the cylindrical body 2 is lowered | hung to a connection position with the support plate 12 using the support plate raising / lowering apparatus 3, and the lower opening end 21 of the cylindrical body 2 of the melting apparatus 100 and the gate valve 280 of the main chamber 200 are connected. Let Note that, when the lower opening end 21 and the gate valve 280 are connected, the gate valve 280 may be closed or opened, but from the viewpoint of preventing dust and the like from entering the main chamber 200, The gate valve 280 is preferably closed.

  Thereafter, the gate valve 280 is opened, and the cylindrical body 2 of the melting apparatus 100 and the main chamber 200 are communicated. Then, an exhaust device (not shown) provided in the main chamber 200 is used to create a vacuum atmosphere in the main chamber 200 and the cylindrical body 2 or under reduced pressure conditions (20 to 30 Torr) Argon (Ar) gas is continuously supplied into the cylindrical body 2 via the gas line 8 to make the main chamber 200 and the cylindrical body 2 have an Ar atmosphere.

  Next, as shown in FIG. 3B (a), the closing plate 22 is lowered by using the closing plate elevating device 5, and as shown in FIG. 3B (b), the cylindrical body 2 is contracted and the heater 4 is turned on. Lower to single crystal raw material heating position. When the heater 4 is lowered, the heat shield 6 and the quartz plate 63 are also lowered integrally with the heater 4.

  Here, the single crystal raw material heating position may be a predetermined position, but from the viewpoint of heating the single crystal raw material 220 with the heater 4 from a position closer to the single crystal raw material 220, a known single unit such as a camera is used. Heater position control that detects the upper end position of the single crystal raw material 220 using a crystal raw material position detection means (not shown) and controls the vertical position of the heater 4 in accordance with the detected upper end position of the single crystal raw material 220. The position is preferably determined by a mechanism (not shown). Thus, if the upper end position of the single crystal raw material 220 in the crucible 210 is detected, the single crystal raw material heating position is determined according to the upper end position of the single crystal raw material 220, and the position of the heater 4 is controlled, a particularly large amount of When the single crystal raw material is melted (for example, when producing a single crystal ingot having a diameter of 300 mm or more, particularly 400 mm or more, more specifically 450 mm in diameter), a part of the single crystal raw material is melted and bulked. This is because even if the upper end position of the single crystal raw material changes with time due to the change in density, the single crystal raw material 220 can always be heated by the heater 4 from a position close to the single crystal raw material 220.

  Then, as shown in FIG. 3B (b), after the heater 4 is lowered to the single crystal raw material heating position, the single crystal raw material 220 in the crucible 210 using the heater 4 and the side heater 230 is melted. Although melting of single crystal raw material 220 may be performed using only heater 4, it is preferable to use side heater 230 together from the viewpoint of melting single crystal raw material 220 more quickly. Incidentally, the output of the side heater 230 (that is, the amount of heat supplied from the side heater 230) when used together with the heater 4 can be made lower than when the single crystal raw material is melted only by the side heater 230.

  Next, after the single crystal raw material 220 in the crucible 210 is completely melted, the supply of electric power to the heater 4 is stopped using the control device 9. Then, as shown in FIG. 4A (a), the closing plate 22 is raised using the closing plate lifting device 5 to extend the cylindrical body 2 and raise the heater 4 to the accommodation position in the cylindrical body 2. . When the heater 4 is raised, the heat shield 6 and the quartz plate 63 are also raised integrally with the heater 4. Incidentally, in order to maintain a single crystal raw material in a molten state, the heating by the side heater 230 is continued.

  Thereafter, the gate valve 280 is closed, and the inside of the cylindrical body 2 and the inside of the main chamber 200 are spatially separated. Here, the inside of the cylindrical body 2 has an atmosphere (a vacuum atmosphere or a reduced pressure atmosphere) similar to that in the main chamber 200. Therefore, before the cylindrical body 2 is disconnected from the gate valve 280, argon gas is supplied into the cylindrical body 2 via the gas supply port 81 and the gas line 8 to increase the pressure inside the cylindrical body 2 to atmospheric pressure. Press. The pressurization in the cylindrical body 2 may be performed by switching the type of gas supplied via the gas supply port 81 by a known means and supplying the atmosphere from the gas supply port 81.

  Next, as shown in FIG. 4A (b), the support plate lifting device 3 is used to raise the cylindrical body 2 together with the support plate 12 to a release position in which the lower opening end 21 and the gate valve 280 are vertically separated. Then, the connection between the lower open end 21 of the cylindrical body 2 of the melting apparatus 100 and the gate valve 280 of the main chamber 200 is released. And after removing the power plug 7, the cooling water supply port 64, and the gas supply port 81 from the external power supply P (external power supply source), the cooling water supply source W, and the gas supply source G, as shown in FIG. 4B (a). Next, the melting apparatus 100 separated from the main chamber 200 is moved. The melting apparatus 100 can be used for melting the single crystal raw material in another main chamber.

  Finally, as shown in FIG. 4B (b), the pull chamber 300 is connected to the gate valve 280 of the main chamber 200 by using the pull chamber swivel raising / lowering device 330, and then known in the pull chamber 300. The inside of the pull chamber 300 is reduced to a pressure equivalent to that in the main chamber 200 using the exhaust device (not shown), and the gate valve 280 is opened. Then, the seed crystal 311 attached to the tip of the wire rope 310 is brought into contact with the melt of the single crystal raw material in the crucible 210 to start pulling up the single crystal.

  As described above, the melting apparatus 100 for the single crystal raw material in the above example is configured to be movable by the wheels 11 provided in the main body 1, so that one melting apparatus 100 is shared among a plurality of main chambers. Can do. Therefore, an increase in equipment cost can be suppressed as compared with the case where the sub-heater is disposed above each main chamber. Moreover, according to the melting apparatus 100, after connecting the cylindrical body 2 to the main chamber 200 using the support plate raising / lowering device 3, the heater 4 is lowered | hung to the single crystal raw material heating position using the closing plate raising / lowering device 5. Thus, the single crystal raw material 220 in the crucible 210 can be directly heated from above without providing a sub-heater inside the main chamber 200. Therefore, the internal structure of the main chamber 200 can be prevented from becoming complicated, and a space for arranging the rectifying cylinder 260 and the raw material charging device can be secured above the crucible 210 of the main chamber 200. Further, the time required for melting the single crystal raw material can be shortened as compared with the case where the single crystal raw material is melted using only the side heater 230, and it is not necessary to heat the crucible with the side heater 230. Therefore, even when a quartz crucible is used, it is possible to suppress dislocation of the pulled up crystal due to deterioration of the crucible at a high temperature.

  Furthermore, according to this melting apparatus 100, since the gas can flow inside the cylindrical body 2 using the gas supply port 81, the gas supply line 8, and the like, the cylindrical body is produced when the single crystal raw material 220 is melted. Argon gas or the like can flow from the second side into the chamber 200. Therefore, the single crystal raw material can be melted in an argon atmosphere, and even when a silicon raw material such as polycrystalline silicon or single crystal silicon is melted as a single crystal raw material, it is generated from the molten single crystal raw material. The SiO gas to be discharged can be exhausted by being placed on the flow of argon gas (downward flow). Further, when the connection between the lower open end 21 of the cylindrical body 2 and the gate valve 280 of the main chamber 200 is released and the cylindrical body 2 is disconnected from the gate valve 280, the inside of the cylindrical body 2 is added with argon gas. Therefore, the connection between the lower opening end 21 and the gate valve 280 can be easily released.

  Further, according to the melting apparatus 100, the heat shield 6 that moves integrally with the heater 4 is provided above the heater 4, so that when the single crystal raw material 220 is heated by the heater 4, The single crystal material 220 can be melted more efficiently in a short time by suppressing heat dissipation to the upper side (tubular body 2 side), and the cylindrical body 2 is deteriorated by the heat from the heater 4. Can be prevented.

  Furthermore, according to the melting apparatus 100, the heater 4 is fixed to the closing plate 22, and the heater 4 is lifted and lowered by moving the closing plate 22 up and down while expanding and contracting the cylindrical body 2 having the bellows structure. The length of the water-cooling electrode can be shortened and the apparatus can be downsized as compared with the case where the water-cooling electrodes 62a and 62b are pushed into the cylindrical body 2 and the heater 4 is moved up and down. Further, according to the melting apparatus 100, the power plug 7, the cooling water supply port 64, and the gas supply port 81 are disposed in the main body 1 so as to be able to be drawn out. Compared with the case where the line and the gas line are directly extended, the apparatus can be reduced in size.

  The single crystal raw material melting apparatus of the present invention has been described above using an example. However, the single crystal raw material melting apparatus of the present invention is not limited to the above example, and the single crystal raw material melting apparatus of the present invention is not limited thereto. Can be appropriately modified.

  Specifically, the cylindrical body may be a cylindrical body having no bellows structure. In this case, the heater can be moved up and down by moving up and down a water-cooled electrode that is airtightly inserted into the closing plate. . The power plug, the cooling water supply port, and the gas supply port may not be provided in the main body 1.

  Further, the tubular body may be provided with a leak valve that enables communication between the inside and the outside of the tubular body. If the leak valve is provided, when the tubular body is separated from the gate valve, the inside of the tubular body can be pressurized to atmospheric pressure simply by opening the leak valve.

  Further, when the support plate lifting / lowering device is functioned as a safety switch and the support plate lifting / lowering device is raised (that is, as shown in FIG. 3A (b), the lower opening end 21 of the cylindrical body 2 is at the release position). If it is located at (5), the electricity may not flow to the heater. In this way, unnecessary power supply to the heater can be prevented, and an accident can be prevented from occurring.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.

Example 1
Using the single crystal raw material melting apparatus shown in FIG. 1, as shown in FIGS. 3A to 4B, a silicon raw material as a single crystal raw material is melted in a quartz crucible and a silicon single crystal having a diameter of 300 mm is pulled up. It was. The silicon raw material was melted under the conditions shown in Table 1, and the single crystal was pulled up a total of nine times using three different main chambers.
Then, the average time required for melting the silicon raw material and the production yield of the silicon single crystal (= (weight of the obtained silicon single crystal / raw material charge amount) × 100%) were obtained. The results are shown in Table 1.

(Conventional example 1)
The silicon raw material was melted in a quartz crucible using only the side heater provided in the main chamber without using the single crystal raw material melting apparatus shown in FIG. 1, and the silicon single crystal having a diameter of 300 mm was pulled up. The silicon raw material was melted under the conditions shown in Table 1, and the single crystal was pulled up a total of nine times using three different main chambers.
Then, the average time required for melting the silicon raw material and the production yield of the silicon single crystal were determined. The results are shown in Table 1.

  From Table 1, it can be seen that in Example 1, the silicon raw material can be melted in a shorter time even with the same power consumption as in Conventional Example 1. Further, Example 1 has a higher yield than Conventional Example 1 (that is, the dislocation of the crystal pulled up as compared with Conventional Example 1 is suppressed), and it can be seen that the crucible deterioration is suppressed.

(Examples 2-3)
The silicon raw material was changed in the same manner as in Example 1 except that the melting conditions of the silicon raw material were changed as shown in Table 2, the diameter of the silicon single crystal to be pulled was changed to 450 mm, and the number of single crystal pulling was changed to 10 times in total. And the silicon single crystal was pulled up.
The average time required for melting the silicon raw material and the production yield of the silicon single crystal were determined in the same manner as in Example 1. The results are shown in Table 2.

(Conventional example 2)
The silicon raw material was changed as shown in Table 2, the diameter of the silicon single crystal to be pulled was changed to 450 mm, and the number of times the single crystal was pulled was set to a total of 10 times. And the silicon single crystal was pulled up.
The average time required for melting the silicon raw material and the production yield of the silicon single crystal were determined in the same manner as in Example 1. The results are shown in Table 2.

  From Table 2, it can be seen that in Example 2, the silicon raw material can be melted in a shorter time even with the same power consumption as in Conventional Example 2. Further, Example 2 has a higher yield than Conventional Example 2 (that is, the dislocation of the crystal pulled up as compared with Conventional Example 2 is suppressed), and it can be seen that the deterioration of the crucible is suppressed. Further, in Example 3 in which the output of the heater was increased, it can be seen that the time required for melting the silicon raw material can be significantly shortened with the same silicon single crystal production yield as in Example 2.

  According to the single crystal raw material melting apparatus of the present invention, the single crystal raw material charged into the crucible can be directly heated from above the crucible while suppressing the complexity of the structure of the main chamber and the increase in equipment cost.

DESCRIPTION OF SYMBOLS 1 Main-body part 2 Cylindrical body 3 Support plate raising / lowering device 4 Heater 5 Closing plate raising / lowering device 6 Heat shield 7 Power plug 8 Gas line 9 Control apparatus 11 Wheel 12 Support plate 13 Guide support | pillar 21 Lower opening end 22 Closing plates 61a and 61b Heater power lines 62a and 62b Water-cooled electrode 63 Quartz plate 64 Cooling water supply port 81 Gas supply port 100 Melting apparatus 200 Main chamber 210 Crucible crucible 210a Quartz crucible 210b Crucible crucible 211 Crucible rotating mechanism 220 Single crystal raw material 230 Side heater 240 Thermal insulation cylinder 250 Thermal insulation Material 260 Rectifier cylinder 280 Gate valve 300 Pull chamber 310 Wire rope 311 Seed crystal 320 Rotating mechanism 321 Pulling mechanism 330 Pull chamber swivel lifting device 400 Single crystal manufacturing device 410 Main chamber 411 Gate valve 412 Crucible 41 Heater 414 single crystal raw material melt 415 heat insulating tube 416 heat insulator 420 pull chamber 421 wire rope 422 seed crystal 423 single crystal ingot

Claims (6)

A melting apparatus used for melting a single crystal raw material charged in a crucible in a main chamber of a single crystal manufacturing apparatus by the Czochralski method,
A main body having a moving mechanism;
A cylindrical body having a lower open end connected to the gate valve of the main chamber of the single crystal manufacturing apparatus, and an upper closed end;
The cylindrical body is moved up and down between a connection position provided on the main body portion, where the lower opening end and the gate valve are connected, and a release position where the lower opening end and the gate valve are separated vertically. A cylindrical body lifting mechanism for raising and lowering;
A heater for heating the single crystal raw material in the crucible protruding downward from the inside of the cylindrical body;
A heater elevating mechanism that is provided in the main body, and moves the heater up and down between an accommodation position in the cylindrical body and a single crystal raw material heating position below the lower opening end;
A connection with a power supply source for supplying power to the heater;
An apparatus for melting a single crystal raw material, comprising: The cylindrical body has a bellows structure;
The heater is fixed to the upper closed end;
The apparatus for melting a single crystal raw material according to claim 1, wherein the heater elevating mechanism elevates and lowers the heater up and down by expanding and contracting the cylindrical body.   The single crystal raw material according to claim 1, further comprising a pressurizing unit that pressurizes the inside of the cylindrical body when the connection between the lower opening end of the cylindrical body and the gate valve is released. Melting equipment.   The apparatus for melting a single crystal raw material according to any one of claims 1 to 3, further comprising gas supply means for supplying a gas into the cylindrical body.   The apparatus for melting a single crystal raw material according to any one of claims 1 to 4, further comprising a heat shield that moves integrally with the heater above the heater.   6. A heater position control mechanism for detecting the position of the single crystal raw material in the crucible and controlling the vertical position of the heater according to the position of the single crystal raw material. An apparatus for melting a single crystal raw material according to claim 1.

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