JP6631468B2 - How to set the nozzle position of the remaining hot water suction device - Google Patents

Description

  The present invention provides a method of setting the nozzle position of a residual hot water suction device when removing residual hot water after pulling up a silicon single crystal from a raw material melt in a crucible by a Czochralski method (Czochralski method: CZ method). And a residual hot water suction device.

  As a method of manufacturing a silicon single crystal used for a semiconductor substrate, a CZ method of growing a silicon single crystal from a raw material melt in a quartz crucible while growing the single crystal has been widely adopted. Further, a magnetic field applied Czochralski method in which a silicon single crystal is pulled up by a CZ method while applying a magnetic field for the purpose of lowering the oxygen concentration of the silicon single crystal and easily manufacturing a large diameter crystal. : MCZ method) is widely known.

  FIG. 3 shows a general silicon single crystal manufacturing apparatus 100. As shown in FIG. 3, a silicon single crystal manufacturing apparatus 100 includes a main chamber 101 that accommodates members such as a quartz crucible 104, a pulling chamber 102 provided on the main chamber 101, and a control of a crystal temperature gradient. Member 109 for heating, a heater 106 for heating and melting the raw material silicon polycrystal, a graphite crucible 105 supporting the quartz crucible 104, and preventing heat from the heater 106 from being directly radiated to the main chamber 101. Heat-insulating material 107, a pull-up wire 114 for pulling up the silicon single crystal 112, a seed holder 113 connected to a lower end of the pull-up wire 114 to mount the seed crystal 118, and a pull-up wire winding for raising and lowering the pull-up wire 114 Device 115 and a crucible supporting crucibles 104 and 105 The shaft 110, an inert gas inlet 116 for introducing an inert gas into the chamber, a gas rectifying tube 108 for introducing the inert gas to the main chamber 101, and an exhaust port 117 for exhausting the inside of the chamber. Is provided. Although not shown, a gate valve for shutting off between the main chamber 101 and the lifting chamber 102, a gas flow control device connected to the inert gas inlet 116, and a vacuum pump connected to the exhaust port of the chamber And a pressure control device.

  The silicon single crystal 112 is pulled up by the CZ method by heating and melting the raw material polycrystalline silicon filled in the quartz crucible 104 with a heater 106 disposed around the raw material polycrystalline silicon, and thereafter, in an inert gas atmosphere, a quartz raw material. The seed crystal 118 attached to the seed holder 113 connected to the tip of the wire 114 is immersed in the raw material melt 103 (silicon melt) in the crucible 104, and the seed crystal 118 is rotated while rotating the quartz crucible 104 and the seed crystal 118. The silicon single crystal 112 having a desired diameter is grown by pulling up the 118. The MCZ method grows a silicon single crystal 112 while applying a magnetic field to the raw material melt 103 in the quartz crucible 104 with the magnet 111 by the CZ method.

  A multi-pooling method (see Non-Patent Document 1) is known as a method of reducing the manufacturing cost in the production of a silicon single crystal by the CZ method. In the multi-pooling method, after pulling up a silicon single crystal having a dopant concentration in a predetermined range, an additional amount of silicon raw material corresponding to the reduced amount of silicon raw material in the crucible is additionally supplied (recharged), and after melting this, This is a method of repeating pulling up a similar silicon single crystal again. According to this method, the manufacturing yield is improved, and a plurality of silicon single crystals can be manufactured from a quartz crucible that can be used only once by a normal CZ method. Therefore, the crucible cost is reduced, and the manufacturing cost of the silicon single crystal is reduced. Can be reduced.

  However, in pulling a silicon single crystal by the CZ method, elements having a segregation coefficient of less than 1 such as Fe, Cu, Ni, and C contained in the silicon raw material are contained in the silicon melt more than the amount taken into the silicon single crystal. The segregated amount is larger and is concentrated in the silicon melt as the silicon single crystal grows. In the multi-pooling method, a new silicon material is recharged to a silicon melt (residual hot water) in which impurities after pulling a silicon single crystal are concentrated, so that an impurity contained in the new silicon raw material is added to the impurities contained in the residual hot water. Join. Therefore, the impurities in the silicon single crystal pulled up after the recharge are larger than the impurities in the silicon single crystal pulled up before the recharge, and the impurities contained in the residual hot water after the silicon single crystal is pulled up after the recharge. Also increase compared to the remaining hot water before recharging. Therefore, when the number of silicon single crystals pulled up by the multi-pooling method is increased, the number of times of recharging also increases, so that impurities in the silicon single crystal increase with the progress of multi-pooling.

  Impurities such as Fe, Cu, Ni, and C taken into the silicon single crystal generate crystal defects and the like during the production of a semiconductor device, and cause a reduction in device yield. Particularly in recent miniaturized devices, there is a strong demand for reduction of impurities in the silicon single crystal. Therefore, the number of silicon single crystals pulled by the multi-pooling method is limited by impurities in the silicon single crystal, and it is difficult to increase the number of pulled silicon single crystals. For this reason, reduction in the manufacturing cost of the silicon single crystal is limited.

  In order to make the impurity of the silicon single crystal pulled up after recharging equal to the impurity of the silicon single crystal pulled up before recharging by this multi-pooling method, it is necessary to remove all the remaining hot water once and recharge all the new silicon raw materials. .

  Therefore, as a measure for reducing impurities in a silicon single crystal in the multi-pooling method, for example, in Patent Document 1, the residual hot water after pulling up the silicon single crystal is removed by a receptacle (remaining hot water suction device) having a tubular member (nozzle). Specifically, it is proposed that the nozzle of the remaining hot water suction device be immersed in the remaining hot water, and then vacuum pressure be applied to the remaining hot water suction device to suction the remaining hot water into the remaining hot water suction device. It is to do.

  As a method of immersing the nozzle of the remaining hot water suction device in the remaining hot water, in Patent Document 1, a gauge is provided under the remaining hot water suction device such that the lower end of the nozzle has a desired depth of the remaining hot water removal amount, A method has been proposed in which the remaining hot water suction device is lowered until the lower end of the gauge contacts the surface of the remaining hot water.

  In such a method, for example, first, after the growth of the silicon single crystal 112 in the silicon single crystal manufacturing apparatus 100 of FIG. 3, the silicon single crystal 112 is pulled up and wound into the chamber 102, and the silicon single crystal 112 is removed from the seed holder 113. And lift it out of the chamber 102.

  Next, as shown in FIG. 4, a conventional residual hot water suction device 11 is attached to the silicon single crystal manufacturing device 100. At this time, the remaining hot water suction device 13 is attached to the seed holder 113 after the silicon single crystal is removed, and the remaining hot water suction device is connected until the lower end of the nozzle 12 connected to the remaining hot water suction device 13 contacts the surface of the remaining hot water 103a. 13 is lowered.

  Next, from the weight (residual hot water weight) obtained by subtracting the weight of the pulled silicon single crystal from the weight of the raw material silicon polycrystal before the pulling of the silicon single crystal and the design dimension value of the quartz crucible 104, quartz from the surface of the residual hot water 103a The distance to the bottom of the crucible 104 is calculated in advance, and the remaining hot water suction device 13 is further lowered by the distance obtained by the calculation.

  If the shape of the quartz crucible 104 is as designed, the position of the lower end of the nozzle 12 of the residual hot water suction device 13 is installed at the bottom of the quartz crucible 104. Since there is a dimensional error due to individual differences, and a dimensional change due to deformation of the quartz crucible 104 that is not constant every time during the pulling of the silicon single crystal, the actual distance from the surface of the residual hot water 103a to the bottom of the quartz crucible 104 is: There is a deviation from the calculated distance.

  However, in this method, regardless of the manufacturing error of the quartz crucible 104 and the change in the depth of the remaining hot water 103a due to the deformation of the quartz crucible 104 generated during the pulling of the silicon single crystal, the depth always set from the surface of the remaining hot water 103a. Only the lower end of the nozzle 12 can be installed.

  Therefore, when removing the entire remaining hot water, as shown in FIG. 5, in the conventional remaining hot water suction device 11, the lower end position of the nozzle 12 of the remaining hot water suction device 13 is too far from the bottom of the quartz crucible 104, and the quartz crucible 104 is removed. In some cases, the remaining hot water 103a could not reach the bottom and could not be completely removed. Alternatively, as shown in FIG. 6, the lower end position of the nozzle 12 of the residual hot water suction device 13 projects into the quartz crucible 104 to close the opening at the lower end of the nozzle 12, so that the residual hot water 103a cannot be removed itself. There was a case.

  In these cases, since the remaining hot water cannot be completely removed, the impurities in the silicon single crystal pulled up after recharging cannot be effectively removed, and may be more than the impurities in the silicon single crystal pulled up before recharging. There is.

  In order to solve this problem, for example, Patent Literature 2 proposes to provide a notch that opens to the side of the lower end of the nozzle. According to this method, the lower end position of the nozzle can always be set at the bottom of the quartz crucible by lowering the residual hot water suction device until the lower end of the nozzle hits the bottom of the quartz crucible. As a result, it is possible to prevent the distance between the lower end of the nozzle and the bottom of the quartz crucible from being too large, and to prevent the remaining hot water from being left unremoved. The remaining hot water can be removed.

  However, in this method, the lower end of the nozzle is held in a state in which the bottom of the nozzle is in contact with the bottom of the quartz crucible until the removal of the remaining hot water is completed. There is a problem in that the residual hot water suction device is raised after removal of the water and cannot be recovered. In this case, since the recharge and the pulling of the silicon single crystal cannot be continued, the remaining hot water suction device cannot be reused, so that the manufacturing cost of the silicon single crystal is rather high.

JP-A-6-72792 JP 2011-57471 A

Semiconductor Silicon Technology, Fumi Shimura, p. 178-p. 179, 1989

  The present invention has been made in view of the above-mentioned problems, and after removing a silicon single crystal from a raw material melt in a crucible by the Czochralski method, the remaining hot water of the raw material melt remaining in the crucible is removed. At this time, a method for setting the nozzle position of the residual hot water suction device and a residual hot water suction device that can stably and more accurately set the nozzle position of the residual hot water suction device so as to be a position where a desired residual hot water amount can be removed. It is intended to provide.

In order to achieve the above object, according to the present invention, after pulling up a silicon single crystal from a raw material melt in a crucible by the Czochralski method, the silicon single crystal is immersed in residual hot water of the raw material melt remaining in the crucible. A method for setting the nozzle position of the remaining hot water suction device when removing the remaining hot water from the crucible with a remaining hot water suction device having a nozzle for sucking the remaining hot water,
A load cell is connected to the remaining hot water suction device, and the remaining hot water suction device is lowered until the lower end of the nozzle of the remaining hot water suction device reaches the bottom of the crucible. The arrival of the lower end of the nozzle at the bottom of the crucible and the position of the bottom of the crucible are detected from the change in weight, and then the distance between the lower end of the nozzle of the residual hot water suction device and the bottom of the crucible is determined. And a method for setting the nozzle position of the residual hot water suction device, wherein

  In this way, the position of the bottom of the crucible can be accurately detected, so that the nozzle position of the remaining hot water suction device can be set more stably and more accurately so that a desired remaining hot water amount can be removed. Can be. This makes it possible to accurately remove the desired amount of remaining hot water.

  At this time, it is preferable that the predetermined distance is set in a range of more than 0 mm and 5 mm or less.

  With this configuration, when removing the entire amount of the remaining hot water, the remaining portion of the remaining hot water removed due to the distance between the lower end of the nozzle and the bottom of the crucible being too wide, or the lower end of the nozzle and the bottom of the crucible adhere to each other. The suspension of multi-pooling due to the inability to collect the remaining hot water suction device can be prevented at the same time. As a result, the impurities in all the silicon single crystals pulled up by the multi-pooling method can be kept equal to the impurities in the silicon single crystal pulled up at the beginning of the multi-pooling.

  At this time, it is preferable to stop the descent of the remaining hot water suction device after detecting that the lower end of the nozzle of the remaining hot water suction device has reached the bottom of the crucible.

  As described above, it is preferable to stop the descent of the remaining hot water suction device after detecting that the lower end of the nozzle of the remaining hot water suction device has reached the bottom of the crucible.

  Further, at this time, it is preferable that after the descent of the remaining hot water suction device is stopped, the remaining hot water suction device is raised to eliminate the contact between the lower end of the nozzle of the remaining hot water suction device and the bottom of the crucible.

  By eliminating the contact between the lower end of the nozzle of the residual hot water suction device and the bottom of the crucible in this way, it is possible to prevent the residual hot water from being unable to be removed.

Further, according to the present invention, there is provided a residual hot water suction apparatus for pulling up a silicon single crystal from a raw material melt in a crucible by a Czochralski method and then sucking the residual hot water of the raw material melt remaining in the crucible. hand,
A remaining hot water suction device provided with a nozzle for immersing the remaining hot water and sucking the remaining hot water, and a load cell connected to the remaining hot water suction device and capable of measuring a change in weight of the remaining hot water suction device. There is provided a residual hot water suction device characterized by having the above.

  In such a case, the position of the bottom of the crucible can be accurately detected by measuring the change in weight with the load cell, so that the remaining hot water suction device is positioned so that a desired remaining hot water amount can be removed. The nozzle position can be set more stably and more accurately. This makes it possible to remove a desired amount of remaining hot water with high accuracy and to exert a cost reduction effect by multi-pooling.

  According to the method for setting the nozzle position of the residual hot water suction device and the residual hot water suction device of the present invention, the position of the bottom of the crucible can be accurately detected, so that the residual hot water can be removed to a desired position. The nozzle position of the hot water suction device can be set stably and more accurately. This makes it possible to accurately remove the desired amount of remaining hot water.

It is the schematic which shows the state which attached the remaining hot-water suction apparatus of this invention to the silicon single crystal manufacturing apparatus. It is the schematic which showed the removal method of the remaining hot water by the method of setting the nozzle position of the remaining hot water suction device of this invention. It is the schematic which showed the general silicon single crystal manufacturing apparatus. It is the schematic which shows the state which attached the conventional residual hot water suction apparatus to the silicon single crystal manufacturing apparatus. It is the schematic which showed typically the case where the lower end of the nozzle of the residual hot water suction device was too far from the bottom of the quartz crucible in the conventional residual hot water removal method. It is the schematic which showed typically the case where the lower end of the nozzle of the residual hot-water suction device bottomed out to the bottom of the quartz crucible in the conventional residual hot-water removal method.

  Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

  As described above, there is a dimensional error due to individual differences in the shape of the quartz crucible, and a dimensional change due to deformation of the quartz crucible that is not constant each time during the pulling of the silicon single crystal occurs. The actual distance to the bottom differs from the calculated distance. Therefore, when the lower end of the nozzle is installed at a depth set from the surface of the remaining hot water, for example, when removing the entire amount of the remaining hot water, the lower end position of the nozzle of the remaining hot water suction device is positioned from the bottom of the quartz crucible as shown in FIG. If the residual hot water cannot be completely removed because it is too far away, or the bottom end of the nozzle of the residual hot water suction device will bottom out into the quartz crucible and close the opening at the lower end of the nozzle as shown in FIG. Could not be done.

  Further, in a method of providing a cut portion opened to the side of the lower end of the nozzle and removing the residual hot water in a state where the lower end of the nozzle is in contact with the quartz crucible, the lower end of the nozzle and the bottom of the quartz crucible are fixed. As a result, there has been a problem that the residual hot water suction device is raised after removal of the residual hot water and cannot be recovered.

  Therefore, the present inventors have conducted intensive studies to solve such a problem. As a result, the setting of the lower end position of the nozzle of the residual hot water suction device is not based on the surface of the residual hot water but on the basis of the bottom of the quartz crucible.

  In order to set the lower end position of the nozzle of the hot water aspirator with reference to the bottom of the quartz crucible, it is necessary to accurately detect the position of the bottom of the quartz crucible. Unlike the surface of hot water, electrical and visual detection is difficult.

  Therefore, the load cell is connected to the remaining hot water suction device, and the remaining hot water suction device is lowered until the lower end of the nozzle of the remaining hot water suction device reaches the bottom of the crucible. When the lower end of the crucible reaches the bottom of the crucible and the position of the bottom of the crucible is detected, and then the distance between the lower end of the nozzle of the residual hot water suction device and the bottom of the crucible is set to a predetermined distance, the bottom of the crucible is detected. Since the position can be accurately detected, it has been found that the nozzle position of the remaining hot water suction device can be set stably and more accurately so that the desired remaining hot water amount can be removed. Then, the best mode for carrying out the above was scrutinized, and the present invention was completed.

  First, the remaining hot water suction device of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing a state in which a remaining hot water suction device 1 of the present invention is attached to a silicon single crystal manufacturing device 100. The residual hot water suction device 1 of the present invention is configured to pull up a silicon single crystal from a raw material melt in a quartz crucible 104 by a Czochralski method, and then to suction the residual hot water 103a of the raw material melt remaining in the quartz crucible 104. It is. The remaining hot water suction device 1 is immersed in the remaining hot water 103a and has a nozzle 2 for suctioning the remaining hot water 103a. The remaining hot water suction device 3 is connected to the remaining hot water suction device 3. And a load cell 4 capable of measuring a change in weight.

  For example, the load cell 4 is connected to a pulling wire 114 to which the remaining hot water suction device 3 is attached via a seed holder 113, and the weight of the remaining hot water suction device 3 is measured by the load cell 4, whereby the nozzle of the remaining hot water suction device 3 is measured. It is possible to measure the change in weight of the remaining hot water suction device 3 when the lower end of 2 comes in contact with the quartz crucible 104.

  In such a case, since the position of the bottom of the quartz crucible 104 can be accurately detected, the position of the nozzle 2 of the residual hot water suction device 3 is stabilized so that a desired residual hot water amount can be removed. Can be set more accurately. This makes it possible to accurately remove the desired amount of remaining hot water.

  The nozzle 2 has, for example, an opening at the lower end, and the remaining hot water 103a can be sucked through the opening.

  In addition, the silicon single crystal manufacturing apparatus 100 to which the residual hot water suction apparatus 1 is attached can be a conventional general apparatus. For example, a main chamber 101 for accommodating a member such as a quartz crucible 104, a pulling chamber 102 provided continuously on the main chamber 101, a heat shielding member 109 for controlling a crystal temperature gradient, and A heater 106 for heating and melting, a graphite crucible 105 supporting the quartz crucible 104, a heat insulating material 107 for preventing heat from the heater 106 from being directly radiated to the main chamber 101, and a silicon single crystal are pulled up. A pulling wire 114, a seed holder 113 connected to a lower end of the pulling wire 114 for mounting a seed crystal, a pulling wire winding device 115 for raising and lowering the pulling wire 114, and a crucible shaft 110 for supporting the crucibles 104 and 105. To introduce inert gas into the chamber. And sexual gas inlet 116, a gas flow-guide cylinder 108 for guiding the inert gas to the main chamber 101, can be made comprising an exhaust port 117 for evacuating the chamber. Further, a magnet 111 for applying a magnetic field to the raw material melt in the quartz crucible 104 during pulling of the silicon single crystal can be provided.

  Although not shown, a gate valve for shutting off between the main chamber 101 and the lifting chamber 102, a gas flow control device connected to the inert gas inlet 116, and a vacuum pump connected to the exhaust port of the chamber And a pressure control device.

  As described above, the main part of the silicon single crystal manufacturing apparatus 100 can be, for example, the same as the silicon single crystal manufacturing apparatus of FIG.

  Next, a method for setting the nozzle position of the residual hot water suction device of the present invention will be described. Hereinafter, the case where the remaining hot water suction device of the present invention as described above is used will be described.

  First, after the silicon single crystal 112 has been grown by the silicon single crystal manufacturing apparatus 100 as shown in FIG. 1, the silicon single crystal 112 is wound up into the pulling chamber 102, the silicon single crystal 112 is removed from the seed holder 113, and the pulling chamber is removed. Take out of 102.

  Next, as shown in FIG. 1, the remaining hot water suction device 1 of the present invention is attached to the silicon single crystal manufacturing device 100 after removing the pulled silicon single crystal. Then, the residual hot water suction device 3 attached to the seed holder 113 is lowered until it reaches the bottom of the quartz crucible 104.

  At this time, as shown in FIG. 2, the remaining hot water suction device 3 is first lowered until the lower end of the nozzle 2 contacts the surface of the remaining hot water 103a, and the weight A of the remaining hot water suction device 3 applied to the pulling wire 114 at this time. Can be measured by the load cell 4 and recorded.

  Then, the remaining hot water suction device 3 is lowered until the lower end of the nozzle 2 connected to the remaining hot water suction device 3 reaches the bottom of the quartz crucible 104, and the weight of the remaining hot water suction device 3 measured by the load cell 4 changes. The arrival of the lower end of the nozzle 2 at the bottom of the quartz crucible 104 and the position of the bottom of the quartz crucible 104 are detected. At this time, for example, it is preferable to lower at a speed of 200 mm / min or less. In addition, the weight B of the remaining hot water suction device 3 at this time is constantly measured by the load cell 4.

  When the lower end of the nozzle 2 of the remaining hot water suction device 3 reaches the bottom of the quartz crucible 104, the weight of the remaining hot water suction device 3 is applied to the quartz crucible 104, and the weight applied to the lifting wire 114 is rapidly reduced. The weight B of the remaining hot water suction device 3 that is constantly measured decreases. By detecting that a difference of, for example, 100 g or more has occurred between the constantly measured weight B and the recorded weight A, the lower end of the nozzle 2 of the residual hot water suction device 3 is moved to the quartz crucible 104. And the position of the bottom of the quartz crucible 104 can be detected.

  At this time, after detecting that the lower end of the nozzle 2 of the remaining hot water suction device 3 has reached the bottom of the quartz crucible 104, it is preferable to stop the lowering of the remaining hot water suction device 3.

  Further, at this time, it is preferable that after the descent of the remaining hot water suction device 3 is stopped, the remaining hot water suction device 3 is raised to eliminate the contact between the lower end of the nozzle 2 of the remaining hot water suction device 3 and the bottom of the quartz crucible 104. . In this way, the opening at the lower end of the nozzle 2 is maintained, and it is possible to prevent the remaining hot water from being unable to be removed.

  Thereafter, the distance between the lower end of the nozzle 2 of the residual hot water suction device 3 and the bottom of the quartz crucible 104 is set to a predetermined distance. By doing so, the position of the bottom of the quartz crucible 104 can be accurately detected, so that the position of the nozzle 2 of the residual hot water suction device 3 can be more stably set so that the desired residual hot water amount can be removed. Can be set accurately. This makes it possible to accurately remove the desired amount of remaining hot water.

  At this time, it is preferable that the predetermined distance is set in a range greater than 0 mm and 5 mm or less. In this way, when removing the entire amount of the remaining hot water, it is possible to prevent the remaining hot water from being left unremoved due to an excessively large distance between the lower end of the nozzle 2 and the bottom of the quartz crucible 104, thereby stably removing the remaining hot water. Can be completely removed. Further, it is possible to simultaneously prevent the multi-pooling from being stopped due to the fact that the lower end of the nozzle 2 and the bottom of the quartz crucible 104 are fixed and the remaining hot water suction device cannot be collected. As a result, the impurities in all the silicon single crystals pulled up by the multi-pooling method can be kept equal to the impurities in the silicon single crystal pulled up at the beginning of the multi-pooling.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited thereto.

(Example)
First, the silicon single crystal 112 was pulled from the raw material melt in the quartz crucible 104 by the CZ method using the silicon single crystal manufacturing apparatus 100 shown in FIG.

  Specifically, a quartz crucible 104 having a diameter of 800 mm is filled with 340 kg of raw silicon polycrystal, which is heated and melted by a heater 106 to obtain a raw material melt, and then a horizontal magnetic field having a central magnetic field strength of 4000 G is applied by a magnet 111. Then, the silicon single crystal 112 having a diameter of 300 mm was pulled up.

  The pulled silicon single crystal was removed from the seed holder 113 connected to the pulling wire 114, and the weight was measured. As a result, the weight of the pulled silicon single crystal 112 was 310 kg. The weight obtained by subtracting the weight (310 kg) of the pulled silicon single crystal from the weight (340 kg) of the raw silicon polycrystal before pulling the silicon single crystal 112 showed that 30 kg of residual hot water remained in the quartz crucible 104. . At this time, the distance from the surface of the remaining hot water to the bottom of the quartz crucible 104 calculated from the design dimension value of the quartz crucible 104 was 70 mm.

  Next, as shown in FIG. 1, the remaining hot water suction device 1 of the present invention was attached to the silicon single crystal manufacturing apparatus 100 after removing the pulled silicon single crystal. Specifically, the remaining hot water suction device 3 provided with the high purity quartz nozzle 2 having a length of 200 mm and a diameter of 30 mm below the remaining hot water suction device 3 was attached to the seed holder 113.

  At this time, the remaining hot water suction device 3 was first lowered until the lower end of the nozzle 2 came into contact with the surface of the remaining hot water 103a. At this time, the weight A of the remaining hot water suction device 3 was measured by the load cell 4 connected to the pulling wire 114, and as a result, was 26.2 kg. The initial weight A of the residual hot water suction device 3 = 26.2 kg was recorded on a computer connected to the load cell 4. According to the program set in the silicon single crystal manufacturing apparatus 100, the weight B measured by the load cell 4 during the descent of the remaining hot water suction device 3 is 100 g larger than the recorded initial weight A of the remaining hot water suction device 3. It was set so that the descent of the remaining hot water suction device 3 would automatically stop when it decreased as described above.

  Next, the remaining hot water suction device 3 was lowered while the weight B of the remaining hot water suction device 3 during the descent was constantly measured by the load cell 4. As a result, when the lower end of the nozzle 2 of the remaining hot water suction device 3 is immersed 76 mm from the surface of the remaining hot water 103a, the weight B constantly measured by the load cell 4 changes from 26.2 kg to 26.1 kg, The lowering of the suction device 3 automatically stopped. At this time, it was detected that the lower end of the nozzle 2 of the residual hot water suction device 3 reached the bottom of the quartz crucible 104.

  Next, the lower end of the nozzle 2 of the remaining hot water suction device 3 which is presumed to be in close contact with the bottom of the quartz crucible 104 is cut off from the bottom of the quartz crucible 104, and the remaining hot water 103a is removed in order to remove the entire remaining hot water 103a. The dispenser 3 was raised by 5 mm, and in this state, a suction operation of sucking the residual hot water 103a into the residual hot water suction device 3 was performed. As a result, it was visually confirmed that almost all of the residual hot water 103a in the quartz crucible 104 was removed.

  From this result, it was found that the installation position of the lower end of the nozzle 2 of the residual hot water suction device 3 could be installed at an appropriate position from the bottom of the quartz crucible 104 by the method of the present invention. If the distance between the lower end of the nozzle 2 of the residual hot water suction device 3 and the bottom of the quartz crucible 104 is set to a range of 5 mm or less, when removing the entire remaining hot water 103a, the lower end of the nozzle 2 and the quartz crucible 104 are removed. It has been found that the removal of the remaining hot water 103a due to the excessively wide distance from the bottom can be prevented, and the entire remaining hot water 103a can be stably removed. Further, by ensuring the distance from the bottom of the quartz crucible in this way, it was possible to prevent the nozzle tip from sticking to the bottom of the crucible.

(Comparative example)
First, a silicon single crystal 112 having a diameter of 300 mm was pulled up using the silicon single crystal manufacturing apparatus 100 shown in FIG. At this time, the weight of the pulled silicon single crystal 112 was 310 kg, and 30 kg of residual hot water remained in the quartz crucible 104. In addition, the distance from the surface of the residual hot water to the bottom of the quartz crucible 104 calculated from the design dimension value of the quartz crucible 104 was 70 mm.

  The pulled silicon single crystal 112 was removed from the seed holder 113 connected to the pulling wire 114, and then, as shown in FIG. 4, the conventional residual hot water suction device 11 was attached to the silicon single crystal manufacturing device 100. At this time, the remaining hot water suction device 13 having a high-purity quartz nozzle 12 having a length of 200 mm and a diameter of 30 mm below the remaining hot water suction device 13 is attached to the seed holder 113, and the lower end of the nozzle 12 has the remaining hot water 103a. The remaining hot water suction device 13 was lowered until it contacted the surface.

  Then, according to the program set in the silicon single crystal manufacturing apparatus 100, the residual hot water suction unit 13 moves from the surface of the residual hot melt to the bottom of the quartz crucible 104 from the surface of the residual hot water calculated from the design dimensions as described above. The descent of the remaining hot water suction device 13 was performed when the lower end of the nozzle 12 of the remaining hot water suction device 13 was in contact with the surface of the remaining hot water 103a when the descent of the remaining hot water suction device 13 was completed. As a result, the descent of the remaining hot water suction device 13 was stopped at a position where the lower end of the nozzle 12 of the remaining hot water suction device 13 was immersed 70 mm from the surface of the remaining hot water 103a.

  Next, in order to remove all the remaining hot water 103a, the remaining hot water 103a is sucked into the remaining hot water suction device 13 while the lower end of the nozzle 12 of the remaining hot water suction device 13 is immersed 70 mm from the surface of the remaining hot water 103a. Was performed. As a result, a part of the residual hot water 103a that could not be removed remained in the quartz crucible 104.

  The remaining hot water suction device 13 was removed from the seed holder 113, and the weight of the remaining hot water 103a removed in the remaining hot water suction device 13 was measured to be 29.7 kg. By subtracting the removed weight 29.7 kg from the weight 30 kg before the removal of the residual hot water 103 a, it can be seen that 0.3 kg of the residual hot water 103 a remained in the quartz crucible 104. When calculated from the design dimensions of the quartz crucible 104, the distance from the surface of the residual hot water 103a remaining in the quartz crucible 104 to the bottom of the quartz crucible 104 at this time was estimated to be about 6 mm.

  From this result, the distance from the surface of the residual hot water 103a to the bottom of the quartz crucible 104 calculated from the design dimension value of the quartz crucible 104 is compared with the actual distance from the surface of the residual hot water 103a to the bottom of the quartz crucible 104. It was found that the installation position of the lower end of the nozzle 12 of the residual hot water suction device 13 was approximately 6 mm above the bottom of the quartz crucible 104.

  Note that the present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same effect. Within the technical scope of

1 ... residual hot water suction device, 2 ... nozzle, 3 ... residual hot water suction device, 4 ... load cell,
100: silicon single crystal manufacturing apparatus, 101: main chamber,
102: lifting chamber 103: raw material melt 103a: residual hot water
104: quartz crucible, 105: graphite crucible, 106: heater,
107: heat insulating material, 108: gas straightening tube, 109: heat shielding member, 110: crucible shaft,
111: magnet, 112: silicon single crystal, 113: seed holder,
114: lifting wire, 115: lifting wire winding device,
116: an inert gas introduction port, 117: an exhaust port, 118: a seed crystal.

Claims (4)

After pulling up a silicon single crystal from the raw material melt in the crucible by the Czochralski method, the silicon single crystal is immersed in the residual hot water of the raw material melt remaining in the crucible, and the residual having a nozzle for sucking the residual hot water is provided. When removing the residual hot water from the crucible with a hot water suction device, a method of setting the nozzle position of the remaining hot water suction device,
A load cell is connected to the remaining hot water suction device, and the remaining hot water suction device is lowered until the lower end of the nozzle of the remaining hot water suction device reaches the bottom of the crucible. The arrival of the lower end of the nozzle at the bottom of the crucible and the position of the bottom of the crucible are detected from the change in weight, and then the distance between the lower end of the nozzle of the residual hot water suction device and the bottom of the crucible is determined. A method for setting the nozzle position of the residual hot water suction device, characterized in that the nozzle position is set to the following distance.   The method for setting a nozzle position of a residual hot water suction device according to claim 1, wherein the predetermined distance is set in a range of more than 0 mm and 5 mm or less.   The suction of the remaining hot water according to claim 1 or 2, wherein the descent of the remaining hot water suction device is stopped after detecting that the lower end of the nozzle of the remaining hot water suction device has reached the bottom of the crucible. How to set the nozzle position of the container.   4. The method according to claim 3, wherein after the descent of the remaining hot water suction device is stopped, the remaining hot water suction device is raised to eliminate contact between the lower end of the nozzle of the remaining hot water suction device and the bottom of the crucible. The method for setting the nozzle position of the residual hot water suction device according to the above.

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