Apparatus and method for manufacturing silicon single crystal

Abstract

To quantify the deformation amount of a quartz crucible to quantitatively grasp the deformation amount.SOLUTION: An apparatus for manufacturing a silicon single crystal includes: a main chamber accommodating a graphite crucible, a quartz crucible interpolated in the graphite crucible and storing a silicon melt, and a heater around the graphite crucible; a crucible rotation mechanism for rotating the graphite crucible; a pulling-up chamber connected to the ceiling part of the main chamber and storing a silicon single crystal pulled up from the silicon melt; a camera for continuously imaging the image of the upper end edge part of the quartz crucible from the ceiling part of the main chamber; an image processing device for processing the image; and a controller for synchronizing with the rotation angle data of the crucible rotation mechanism to record the position data of the upper end edge part of the quartz crucible on the basis of the processing data of the image processing device and quantify the change of position of the upper end edge part of the quartz crucible as the deformation amount of the quartz crucible.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a silicon single crystal manufacturing apparatus and a silicon single crystal manufacturing method using the Czochralski method (hereinafter also referred to as the CZ method), and in particular to a technique for quantifying the deformation amount of a quartz crucible. [Background technology]

[0002] 2. Description of the Related Art As a method for producing silicon single crystals used in the manufacture of semiconductor devices, the CZ method, in which a silicon single crystal is grown from a raw material melt (silicon melt) in a quartz crucible inserted in a graphite crucible, is widely used. In the CZ method, polycrystalline raw material packed in a quartz crucible is heated and melted using a cylindrical heater in an inert gas atmosphere, and a seed crystal is immersed in the silicon melt and pulled up while rotating the quartz crucible and the seed crystal, thereby pulling up a silicon single crystal. The graphite crucible is placed on a crucible tray, and a pedestal that supports the crucible tray is connected to the crucible shaft, allowing it to rise and fall and rotate.

[0003] In recent years, the diameter of single crystal ingots being pulled has increased, which has resulted in larger quartz crucibles and larger thermal loads during melting of the raw material. When polycrystalline raw material packed in a quartz crucible is heated and melted by a cylindrical heater, the melting point of silicon is as high as 1420°C, and the temperature of the quartz crucible becomes even higher. At such high temperatures, the quartz crucible becomes soft and may deform due to the weight of the crucible walls. This deformation generally occurs when the walls of the quartz crucible collapse or buckle inward, causing the upper edge to sink. Therefore, in order to correct the deformation of the wall surface of the quartz crucible, a method has been proposed in which the wall surface of the quartz crucible is pressed from the inside by a protrusion provided at the tip of a support rod (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-336021 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, it is important to consider a method for correcting the deformation of the wall surface of the quartz crucible, assuming that the deformation occurs. However, in the method of inserting the tip of a support rod into the rotating high-temperature quartz crucible to mechanically contact it, as in Patent Document 1, new problems may arise, such as the durability of the support rod and the loss of heat escaping to the outside from the insertion port. On the other hand, as another approach, it is also important to clarify the cause of deformation of the wall of the quartz crucible and prevent it from occurring. For this purpose, it is preferable to quantify the amount of deformation of the quartz crucible during heating and quantitatively grasp under what conditions the amount of deformation increases.

[0006] According to the inventor's research, the above-mentioned quartz crucible collapse is most likely to occur from the start of initial melting of the polycrystalline raw material until seeding. Therefore, currently, based on past experience, the initial melting conditions are determined by devising the positional relationship between the heater (graphite heater) and the quartz crucible during melting and the way power is applied to the graphite heater. Here, the initial melting conditions refer to the period from when power is applied to the graphite heater with the polycrystalline silicon raw material placed in the quartz crucible to when the silicon melt is adjusted to a temperature suitable for seeding.

[0007] Furthermore, once a collapse occurs, the amount of collapse increases over time. Therefore, if the deformation progresses to the point during growth of the silicon single crystal that it is about to come into contact with the heat shielding member arranged around the crystal, it becomes difficult to continue growing the silicon single crystal, and it is necessary to separate the silicon single crystal from the silicon melt and discontinue production.

[0008] In addition, when using the multi-pooling method in which, after pulling up a silicon single crystal, the silicon melt is replenished by filling and melting additional polycrystalline silicon equal to the pulled weight, and then the silicon single crystal is pulled up again several times, if the quartz crucible begins to tip over, it is necessary to decide whether to proceed to the next crystal, since interrupting the process halfway through will result in a decrease in yield and an increase in production costs.

[0009] Furthermore, the degree of deformation of the quartz crucible is judged by the operator through a sight window installed in the chamber, either visually or by checking the image of a camera installed in the chamber. In order to judge the degree of the quartz crucible's collapse from the sight window with a limited field of view, it is necessary to constantly monitor the quartz crucible while it is rotating, which is a heavy burden, and since the degree of collapse is not quantitatively measured, there are individual differences in the decision to continue growing silicon single crystals or to move on to the next one in multi-pooling when the gap between the quartz crucible and the heat shielding member becomes narrow.

[0010] The present invention has been made to solve the above problems, and an object of the present invention is to convert the amount of deformation of a quartz crucible into a numerical value so that it can be quantitatively understood. [Means for solving the problem]

[0011] In order to solve the above problems, the silicon single crystal manufacturing apparatus of the present invention is a silicon single crystal manufacturing apparatus that pulls up a silicon single crystal by the Czochralski method, and includes a main chamber that houses a graphite crucible, a quartz crucible that is inserted into the graphite crucible and contains a silicon melt, and a heater around the graphite crucible, a crucible rotation mechanism that rotates the graphite crucible, a pulling chamber that is connected to the ceiling of the main chamber and contains the silicon single crystal pulled up from the silicon melt, a camera that continuously takes images of the upper edge of the quartz crucible from the ceiling of the main chamber, an image processing device that processes the images, and a control device that records position data of the upper edge of the quartz crucible based on processed data of the image processing device in synchronization with rotation angle data of the crucible rotation mechanism, and quantifies a change in the position of the upper edge of the quartz crucible as a deformation amount of the quartz crucible.

[0012] Such a silicon single crystal manufacturing device processes continuously captured images, records position data of the upper edge of the quartz crucible synchronized with the rotation angle data, and quantifies the change in position as the deformation amount of the quartz crucible, making it possible to identify and quantitatively grasp the timing at which the deformation amount increases (at what point in the period of continuously captured images does the deformation amount increase, and at what angle during one rotation does the deformation amount increase).This makes it possible to analyze under what conditions the deformation amount increases, etc.

[0013] The present invention also provides a method for producing a silicon single crystal using the silicon single crystal production apparatus described above, comprising the steps of: containing the silicon melt in the quartz crucible; rotating the graphite crucible with the crucible rotation mechanism; heating the graphite crucible from the surroundings with the heater; continuously taking images of the upper edge of the quartz crucible with the camera; processing the images with the image processing device; and recording position data of the upper edge of the quartz crucible based on the processed data of the image processing device with the control device in synchronization with the rotation angle data of the crucible rotation mechanism; and quantifying the change in the position of the upper edge of the quartz crucible as the amount of deformation of the quartz crucible.

[0014] In such a method for producing silicon single crystals, the images taken continuously during heating are processed to record the position data of the upper edge of the quartz crucible synchronized with the rotation angle data, and the change in position is quantified as the deformation amount of the quartz crucible, so that the timing at which the deformation amount increases can be identified and quantitatively understood. This makes it possible to analyze under what conditions the deformation amount increases.

[0015] It is also preferable to have a heat shielding member disposed within the main chamber facing the silicon melt and surrounding the silicon single crystal, and to calculate the distance between the heat shielding member and the quartz crucible from the amount of deformation of the quartz crucible.

[0016] By using this method of calculating the distance between the heat shielding member and the quartz crucible, it is possible to grasp whether the quartz crucible has been deformed and the distance has become narrower.

[0017] Furthermore, it is preferable that the rotation angle data is further recorded in synchronization with at least one data of parameters related to pulling of the silicon single crystal, including the heater power, the position of the quartz crucible, the position of the heater, the Ar gas flow rate, and the furnace pressure.

[0018] With this method, rotation angle data, position data of the upper edge of the quartz crucible, and at least one parameter related to the pulling of silicon single crystals are recorded synchronously, making it possible to clearly determine whether there is a correlation between the increase in deformation of the quartz crucible and the parameter.

[0019] It is also preferable to determine initial melting conditions based on the deformation amount of the quartz crucible and at least one data item of parameters related to the pulling of the silicon single crystal, and to pull the silicon single crystal after implementing the initial melting conditions.

[0020] By using this method, it is possible to quantitatively grasp whether the amount of deformation of the quartz crucible increases during implementation of the initial melting conditions and during pulling of the silicon single crystal. For example, if the amount of deformation is large during implementation of the initial melting conditions, it is found that the parameter that determined the initial melting conditions is the cause, and if the amount of deformation during implementation of the initial melting conditions is small (or there is no deformation), it is found that there is no problem with the parameter that determined the initial melting conditions.

[0021] It is also preferable that when the distance between the heat shielding member and the quartz crucible falls below a preset threshold value, the silicon single crystal is separated to terminate production.

[0022] With this method, even if the quartz crucible gradually deforms and falls inward, production can be safely terminated before the quartz crucible comes into contact with the heat shielding member. For example, if the quartz crucible comes into contact with the heat shielding member, there is a risk that the raw material melt will be contaminated or the heat shielding member will be damaged and become unusable, but this can be avoided.

[0023] In addition, in a multi-pooling method in which, after the silicon single crystal is pulled up, the silicon melt is replenished by additionally filling and melting polycrystalline silicon equivalent to the pulled weight, and then the silicon single crystal is pulled up again, the process is repeated. When the distance between the heat shielding member and the quartz crucible falls below a preset threshold value, it is preferable to end production without moving on to the next crystal as initially set.

[0024] This method makes it possible to avoid a situation in which the quartz crucible comes into contact with the heat shielding member during production by continuing production of the next piece without finishing the production.

[0025] It is also preferable that the method of processing the image by the image processing device is a method of binarizing the brightness or color of the image captured by the camera.

[0026] By using such a binarization method, the boundary between the top edge of the quartz crucible captured by the camera and the background can be easily clarified. Effect of the Invention

[0027] As described above, the silicon single crystal manufacturing apparatus of the present invention processes continuously captured images, records position data of the upper edge of the quartz crucible synchronized with the rotation angle data, and quantifies the change in position as the deformation amount of the quartz crucible, so that the timing at which the deformation amount increases can be identified and quantitatively understood. This makes it possible to analyze under what conditions the deformation amount increases. As a result, in the silicon single crystal growing process, it becomes possible to find melting conditions that cause less deformation of the quartz crucible and to easily determine whether the process can be continued, thereby providing a silicon single crystal manufacturing apparatus with a higher yield. [Brief description of the drawings]

[0028] [Figure 1] 1 is an overall configuration diagram of a silicon single crystal manufacturing apparatus according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a schematic diagram showing an image of image processing of the upper edge portion of a quartz crucible. [Diagram 3] 1 is a graph showing the coordinates of the upper edge of a quartz crucible versus the rotation angle before and after silicon single crystal production. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] As described above, there was a need to quantify the amount of deformation of a quartz crucible in silicon single crystal manufacturing equipment using the CZ method and to quantitatively understand under what conditions the amount of deformation increases.

[0030] The inventors therefore completed the present invention by continuously taking images of the upper edge of a quartz crucible with a camera attached to the ceiling, and then quantifying the amount of deformation of the quartz crucible through image processing, making it possible to quantitatively understand under what conditions the amount of deformation increases.

[0031] That is, this is a silicon single crystal manufacturing apparatus that pulls up a silicon single crystal by the Czochralski method, comprising: a main chamber that houses a graphite crucible, a quartz crucible that is inserted into the graphite crucible and contains a silicon melt, and a heater around the graphite crucible; a crucible rotation mechanism that rotates the graphite crucible; a pulling chamber that is connected to the ceiling of the main chamber and contains a silicon single crystal pulled up from the silicon melt; a camera that continuously takes images of the upper edge of the quartz crucible from the ceiling of the main chamber; an image processing device that processes the images; and a control device that records position data of the upper edge of the quartz crucible based on processed data of the image processing device in synchronization with rotation angle data of the crucible rotation mechanism, and quantifies a change in the position of the upper edge of the quartz crucible as a deformation amount of the quartz crucible.

[0032] Hereinafter, one embodiment of the present invention will be described with reference to Figs. 1 to 3, however, the present invention is not limited thereto.

[0033] FIG. 1 is a diagram showing the overall configuration of a silicon single crystal manufacturing apparatus according to the present invention. This is a silicon single crystal manufacturing apparatus 2 that pulls up a silicon single crystal 1 by the Czochralski method, and includes a main chamber 7 that houses a graphite crucible 3, a quartz crucible 5 that is inserted into the graphite crucible 3 and contains a silicon melt 4, and a heater 6 that surrounds the graphite crucible 3, a crucible rotation mechanism 8 that rotates the graphite crucible 3, and a pulling chamber 10 that is connected to a ceiling part 9 of the main chamber 7 and contains the silicon single crystal 1 pulled up from the silicon melt 4. The apparatus further includes a camera 11 that continuously captures images of the upper edge of the quartz crucible 5 from the ceiling part 9 of the main chamber 7, an image processing device 12 that processes the images, and a control device 13 that records position data of the upper edge of the quartz crucible 5 based on the processed data of the image processing device 12 in synchronization with the rotation angle data of the crucible rotation mechanism 8, and quantifies the change in the position of the upper edge of the quartz crucible 5 as the deformation amount of the quartz crucible 5. Furthermore, a heat shielding member 14 is disposed opposite the silicon melt 4 and surrounding the silicon single crystal 1 being pulled.

[0034] With such a silicon single crystal manufacturing apparatus 2, particularly having the above-mentioned camera 11, image processing device 12, and control device 13, it is possible to identify the timing at which the amount of deformation increases (at what point during the period of continuous imaging the amount of deformation increases, and at what angle during one rotation the amount of deformation increases), and to quantitatively grasp the conditions under which the amount of deformation increases.

[0035] Next, an example of a method for manufacturing a silicon single crystal 1 of the present invention using this silicon single crystal manufacturing apparatus 2 will be described. A silicon melt 4 is placed in a quartz crucible 5, and the graphite crucible 3 is heated from the periphery by a heater 6 while being rotated by a crucible rotation mechanism 8. At this time, images of the upper edge of the quartz crucible 5 are continuously taken by a camera 11, the images are processed by an image processing device 12, and position data of the upper edge of the quartz crucible 5 is recorded by a control device 13 based on the processed data of the image processing device 12 in synchronization with the rotation angle data of the crucible rotation mechanism 8, and the change in the position of the upper edge of the quartz crucible 5 is quantified as the deformation amount of the quartz crucible 5.

[0036] With such a method for producing silicon single crystal 1, it is possible to identify the timing at which the amount of deformation increases and to quantitatively grasp it. This makes it possible to analyze under what conditions the amount of deformation increases.

[0037] The above-mentioned image processing, data synchronization, and quantification of the deformation amount of the quartz crucible will be described in more detail below. The image captured by the camera 11 is subjected to an image processing device 12 for binarizing the brightness or color data, so that the boundary between the upper edge of the quartz crucible 5 and the background can be easily clarified.

[0038] FIG. 2 is a schematic diagram showing an image obtained by image processing of the upper edge of a quartz crucible.

[0039] With regard to the boundary between the top edge of the quartz crucible 5 and the background, which has been made clear by image processing, the intersection point (intersection at the inner edge) 22a between the boundary of the inner edge of the top edge of the quartz crucible 5 and an arbitrarily set reference line 21, and the intersection point (intersection at the outer edge) 22b between the boundary of the outer edge of the top edge of the quartz crucible 5 and the reference line 21 are determined, and when the X-axis is the circumferential direction of the quartz crucible and the Y-axis is the radial direction (reference line 21), the respective Y coordinate values ​​are transferred to the control device 13.

[0040] The quartz crucible 5 is rotated at an arbitrary rotation speed together with the graphite crucible 3 by the crucible rotation mechanism 8, so that by recording data on the intersections 22a, 22b with each edge measured on the reference line 21 in synchronization with the rotation angle θ obtained from the crucible rotation mechanism 8, data for the entire circumference of the quartz crucible can be obtained.

[0041] Since the rotation speed of the quartz crucible may vary depending on the process or equipment, it is effective to obtain data on the upper edge of the quartz crucible in synchronization with the rotation angle θ obtained by the crucible rotation mechanism as described above. For example, even if the rotation speed changes depending on the recipe, data can always be obtained from the same position, making it possible to observe the progress of deformation more easily and in detail.

[0042] Furthermore, it is preferable that the rotation angle data is recorded in synchronization with at least one data of parameters related to pulling of silicon single crystals, such as heater power in each process, quartz crucible position, heater position, Ar gas flow rate, furnace pressure, etc. By comparing the deformation data of the quartz crucible at a specified rotation angle with the actual data of the parameters in each process, it becomes easy to analyze the conditions that induce the deformation.

[0043] Figure 3 is a graph showing the coordinates of the upper edge of the quartz crucible versus the rotation angle before and after silicon single crystal production. The dashed line a shows the change in coordinates before production, measured without applying power to the heater, and the solid line b shows the change in coordinates after production, when power is applied to the heater and the raw material is melted and the single crystal is pulled up. In this way, the deformation of the quartz crucible before and after production can be visualized, and it is easy to see that although there was little change before production, the change has increased and deformation has occurred after production. Furthermore, by calculating the difference between a and b, the direction of deformation can be identified and expressed quantitatively.

[0044] In addition, by setting an arbitrary point as the position of the heat shielding member 14 (hereinafter referred to as the 0 point position) and taking the difference from that point with the solid line b, it is possible to quantitatively express the distance (hereinafter referred to as the gap) between the heat shielding member 14 and the upper edge of the quartz crucible.

[0045] In addition, when capturing an image of the top edge of the quartz crucible, it is desirable to position the camera directly above the end face of the quartz crucible. If the camera is positioned in this way, the position of the top edge of the quartz crucible will not shift even if the position of the quartz crucible changes. It is also possible to capture an image of the top edge of the quartz crucible by angling the camera, but in that case, it is necessary to make corrections taking into account that the position of the top edge of the quartz crucible moves depending on the position of the quartz crucible.

[0046] When the gap falls below a preset threshold, it is preferable to separate the silicon single crystal and terminate the production.

[0047] With this method, even if the quartz crucible gradually deforms and falls inward, production can be safely terminated before the quartz crucible comes into contact with the heat shielding member. For example, if the quartz crucible comes into contact with the heat shielding member, there is a risk that the raw material melt will be contaminated or the heat shielding member will be damaged and become unusable, but this can be avoided.

[0048] In addition, in the multi-pooling method in which, after pulling up a silicon single crystal, the silicon melt is replenished by filling and melting additional polycrystalline silicon equivalent to the pulled weight, and then pulling up a silicon single crystal again, the process is repeated several times (repeated once or more), and when the gap falls below a preset threshold value, it is preferable to end production without moving on to the next crystal as initially set.

[0049] This method makes it possible to avoid a situation in which the quartz crucible comes into contact with the heat shielding member during production by continuing production of the next piece without finishing the production.

[0050] It is preferable to determine the initial melting conditions based on the deformation amount of the quartz crucible and at least one of the parameters related to pulling the silicon single crystal (heater power, quartz crucible position, heater position, Ar gas flow rate, furnace pressure, etc.), and to pull the silicon single crystal after implementing the initial melting conditions.

[0051] By using this method, it is possible to quantitatively grasp the change in the deformation amount of the quartz crucible during the implementation of the initial melting conditions and during the pulling of the silicon single crystal. For example, if the deformation amount during the implementation of the initial melting conditions is large, it is found that the parameter that determined the initial melting conditions is the cause, and if the deformation amount during the implementation of the initial melting conditions is small (or there is no deformation), it is found that there is no problem with the parameter that determined the initial melting conditions.

[0052] For example, if the deformation of the quartz crucible increases while the initial melting conditions are being implemented, adjustments can be made to prevent the deformation from increasing by lowering the heater power, which is a setting parameter of the initial melting conditions, or by changing the position of the heater. EXAMPLES

[0053] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0054] [Example 1]

[0055] Under the following conditions, the silicon single crystal manufacturing apparatus of the present invention shown in Figures 1 and 2 was used to carry out the manufacturing method of the present invention (imaging of the quartz crucible, image processing, synchronization of the heater power with the quartz crucible position and the rotation angle data of the heater position, and quantification of the deformation amount), while pulling crystals in 10 batches, with each batch being set to 5 pulls. ·Quartz crucible: Outer diameter 800mm Charge capacity: 400kg Single crystal diameter: 306mm Graphite heater: External diameter 975mm -Multiple pull settings: 5 pulls Initial melting conditions: (1) Improved initial melting conditions created by analyzing the data of the present invention

[0056] Here, (1) the outline of the improved initial melting conditions prepared by analyzing the data of the present invention is as follows: First, as a preliminary step, the change in the position of the upper edge of the quartz crucible was quantified as the deformation amount of the quartz crucible by the method of the present invention while carrying out the manufacturing process with the parameters related to the conventional pulling of silicon single crystals. The conventional initial melting condition was to lower the power of the graphite heater after the melting was completed, return the graphite heater, which was relatively lower than the graphite crucible, to the same height, and prepare for the next seeding. However, it was found by analyzing the data that the crucible had been falling over since that operation. It was considered that this was caused by the fact that the temperature of the graphite heater itself does not drop immediately even if the power of the graphite heater is lowered, and it was decided to adjust the position of the graphite heater after lowering the power and waiting for a predetermined time. This was set as the initial melting condition (1), and Example 1 was carried out under this initial melting condition (1).

[0057] The following are the criteria for judging whether or not harmful quartz crucible collapse occurs in the examples. ·Whether or not the quartz crucible falls after the initial melting is completed: The presence or absence is judged by setting a threshold value (30 mm) for the distance between the quartz crucible and the heat shielding material. ·Whether or not the quartz crucible that stops the transition to the next multi-pooling has fallen: The presence or absence is judged by setting a threshold value (10 mm) for the distance between the quartz crucible and the heat shielding material. -Whether or not the quartz crucible falls during crystal pulling, which requires the crystal to be separated: The presence or absence is judged by setting a threshold value (5 mm) for the distance between the quartz crucible and the heat shielding material. The distance between the quartz crucible and the heat shielding member was calculated from data obtained by the manufacturing method of the present invention.

[0058] The results were as follows: (Results of a quartz crucible falling over) Number of collapses after initial melting: 0 / 10 batches - Quartz crucible collapse that stops the transition to the next batch of multi-pooling: 1 case / 10 batches - Quartz crucible collapse during crystal pulling requiring crystal separation: 0 / 49

[0059] In one batch, during recharge melting before pulling the fourth multi-pooling crystal, the polycrystalline raw material adhered to the wall of the quartz crucible, and when melting and removing the adhesion, the graphite heater was raised higher than normal, causing the quartz crucible to fall over. The crystal was able to be pulled up without any problems because the gap between the quartz crucible and the heat shielding member did not reach the threshold value that would require the crystal to be separated. However, since the threshold standard for the distance between the quartz crucible and the heat shielding member, which would stop the transition to the next multi-pooling, was exceeded, the batch was terminated after four multi-poolings. As a result, only 49 units were produced, one less than planned.

[0060] [Comparative Example 1] Under the following conditions, a conventional silicon single crystal manufacturing apparatus, which does not have the camera, image processing device, or control device of the manufacturing apparatus of the present invention, was used to pull crystals by the conventional pulling method in 10 batches, with each batch being set to pull 5 crystals. ·Quartz crucible: Outer diameter 800mm Charge capacity: 400kg Single crystal diameter: 306mm Graphite heater: External diameter 975mm -Multiple pull settings: 5 pulls Initial melting conditions: (2) Conventional initial melting conditions

[0061] The criteria for determining whether harmful quartz crucible toppling occurred or not were the same as in Example 1, but the distance between the quartz crucible and the heat shielding member was determined by an operator through a sight glass by visual inspection.

[0062] The results were as follows: (Results of a quartz crucible falling over) Number of collapses after initial melting: 3 / 10 batches - Quartz crucible collapse that stops the transition to the next batch of multi-pooling: 3 cases / 10 batches - Quartz crucible falling during crystal pulling requiring crystal separation: 1 case / 45 pieces

[0063] In the third batch, the collapse of the quartz crucible that occurred during the initial melting progressed, so measures were taken to reduce the number of multi-pooling pieces from the set five to three, three, and four. In one of the batches, the fourth piece was produced, but the possibility of contact between the heat shielding material and the quartz crucible was detected midway through the process, so the batch was cut off and ended. A large amount of molten liquid remained, significantly reducing the yield. The operator's decision to move on to the fourth piece was likely due to inconsistencies in the measurement of the gap between the heat shielding material and the quartz crucible. In the end, only 45 units were produced, five fewer than planned.

[0064] From the above, it was shown that Example 1 of the present invention can reduce the risk of pulling interruption or equipment failure (contact between the heat shielding member and the quartz crucible) and can increase the yield compared to the conventional Comparative Example 1. In addition, it was found that the amount of deformation of the quartz crucible can be quantified and quantitatively determined, which results in high accuracy of determination and reduces the burden on the operator.

[0065] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any configuration that is substantially the same as the technical idea described in the claims of the present invention and that provides similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0066] DESCRIPTION OF SYMBOLS 1...silicon single crystal, 2...silicon single crystal manufacturing apparatus of the present invention, 3...graphite crucible, 4...silicon melt, 5...quartz crucible, 6...heater, 7...main chamber, 8...crucible rotation mechanism, 9...ceiling, 10...pulling chamber, 11...camera, 12...image processing device, 13...control device, 14...heat shielding member, 21...reference line, 22a...intersection (intersection at inner edge), 22b...intersection (intersection at outer edge), 23...arbitrary point. a...dashed line (change in coordinates before manufacturing), b...solid line (change in coordinates after manufacturing), θ...rotation angle.

Claims

1. A silicon single crystal manufacturing apparatus for pulling a silicon single crystal by the Czochralski method, a main chamber that houses a graphite crucible, a quartz crucible that is inserted into the graphite crucible and contains silicon melt, and a heater that surrounds the graphite crucible; a crucible rotation mechanism that rotates the graphite crucible; a pulling chamber connected to a ceiling of the main chamber and configured to accommodate the silicon single crystal pulled from the silicon melt; A camera that continuously captures images of the upper edge of the quartz crucible from the ceiling of the main chamber; an image processing device for processing the image; A control device that records position data of the upper edge of the quartz crucible based on the processing data of the image processing device in synchronization with the rotation angle data of the crucible rotation mechanism, and quantifies the change in the position of the upper edge of the quartz crucible as a deformation amount of the quartz crucible; A silicon single crystal manufacturing apparatus comprising:

2. A method for producing a silicon single crystal using the silicon single crystal production apparatus according to claim 1, The silicon melt is placed in the quartz crucible; While rotating the graphite crucible by the crucible rotation mechanism, the graphite crucible is heated from the periphery by the heater, and images of the upper edge portion of the quartz crucible are continuously captured by the camera; processing the image with the image processing device; A method for producing silicon single crystals, characterized in that the control device records position data of the upper edge of the quartz crucible based on the processed data of the image processing device in synchronization with the rotation angle data of the crucible rotation mechanism, and quantifies the change in the position of the upper edge of the quartz crucible as the deformation amount of the quartz crucible.

3. a heat shielding member disposed in the main chamber so as to face the silicon melt and surround the silicon single crystal; 3. The method for producing a silicon single crystal according to claim 2, wherein the distance between the heat shielding member and the quartz crucible is calculated from the deformation amount of the quartz crucible.

4. The method for producing a silicon single crystal according to claim 2 or 3, characterized in that the rotation angle data is further recorded in synchronization with at least one data of parameters related to pulling the silicon single crystal, including the heater power, the position of the quartz crucible, the position of the heater, the Ar gas flow rate, and the furnace pressure.

5. The method for producing a silicon single crystal according to claim 4, characterized in that an initial melting condition is determined based on the deformation amount of the quartz crucible and at least one data of a parameter related to the pulling of the silicon single crystal, and the pulling of the silicon single crystal is carried out after the initial melting condition is implemented.

6. 4. The method for producing a silicon single crystal according to claim 3, wherein when the distance between the heat shielding member and the quartz crucible falls below a preset threshold value, the silicon single crystal is separated and production is terminated.

7. In a multi-pooling method, after the silicon single crystal is pulled up, the silicon melt is replenished by additionally filling and melting polycrystalline silicon in an amount equivalent to the weight of the silicon single crystal pulled up, and then the silicon single crystal is pulled up again. The method for producing a silicon single crystal according to claim 3, characterized in that, when the distance between the heat shielding member and the quartz crucible falls below a preset threshold value, production is terminated without moving on to the next crystal as initially set.

8. 3. The method for producing a silicon single crystal according to claim 2, wherein the method for processing the image by the image processing device is a method for binarizing the brightness or color of the image captured by the camera.

Images