JP2021130574A - Method for manufacturing silicon single crystal - Google Patents

Abstract

To provide a method for suppressing Fe contamination sometimes caused by exchanging a HZ component in the peripheral part of a single crystal.SOLUTION: A method for manufacturing a silicon single crystal, capable of pulling the silicon single crystal from a silicon melt stored in a crucible by the CZ method using a manufacturing apparatus including a HZ component and cylindrically grinding the silicon single crystal into a product diameter comprises: previously acquiring correlation among a period of time using the apparatus after exchanging the HZ component positioned above the surface of the silicon melt, a grinding amount cylindrically ground from the as-grown diameter of the pulled silicon single crystal and an Fe concentration in the peripheral part of the silicon single crystal at the ground amount; and controlling the as-grown diameter of the pulled silicon single crystal so as to obtain a cylindrically ground amount at which the Fe concentration in the peripheral part of the silicon single crystal having the product diameter is equal to or less than a target Fe concentration on the basis of the correlation.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a silicon single crystal by the Czochralski method (CZ method).

In the production of a single crystal by the CZ method, the pulling speed is closely related to the temperature gradient in the pulling direction of the single crystal to be pulled, and the pulling speed can be increased by increasing the temperature gradient. Therefore, hot zone (HZ) parts such as a heat shield tube are arranged so as to surround the circumference of the single crystal to shield the radiant heat from the heater, the rutsubo, and the raw material melt, and to set the temperature gradient in the pulling direction of the single crystal. A method of increasing the temperature and a heat absorbing cylinder that promotes heat transfer of radiant heat from the asgrown crystal to a water-cooled chamber in order to increase the temperature gradient in the pulling direction of the single crystal are adopted.

In the production of a silicon semiconductor crystal by the CZ method, a silicon raw material melt is generated in a quartz crucible in a furnace, a seed crystal is deposited, and a single crystal is pulled up. During the production of a silicon single crystal, oxygen dissolves from the inner surface of the quartz crucible into the silicon raw material melt, which reacts with the silicon raw material melt to generate _{silicon oxide (SiO and SiO 2).} In addition, silicon oxide reacts with graphite members such as heaters to generate _{CO and CO 2.} Silicon oxide is sublimable, and when the temperature drops in the furnace, it becomes a solid and falls into the silicon raw material melt, causing dislocations during single crystal growth. CO and CO ₂ are incorporated into the raw material melt and cause carbon contamination of the crystals. Therefore, in order to discharge these harmful gases, an inert gas such as Ar gas is circulated in the furnace.

The temperature of the HZ component in the furnace during the production of the silicon single crystal is high, and the impurities present in the HZ member are released from the surface of the component into the inert gas by thermal diffusion. When the inert gas comes into contact with the growing silicon single crystal, the impurities in the inert gas diffuse from the surface of the silicon single crystal and contaminate the single crystal, increasing the impurity concentration on the outer surface of the single crystal and processing the wafer. Even after that, defective impurities on the outer surface occur.

On the other hand, in addition to reducing contamination by cleaning the manufacturing process, the contamination of single crystals has been improved by increasing the purity of raw materials and HZ parts. However, with the progress of further miniaturization of semiconductor devices, further reduction of impurities is required.

As mentioned above, the HZ parts used for single crystal production are those that have undergone high-purity treatment, but impurity contamination may remain on the base material of the HZ parts, and immediately after replacing the HZ parts. Therefore, the amount of heavy metal contamination on the outer surface of the silicon single crystal becomes high, which may result in poor quality of the silicon single crystal.

In order to reduce the amount of heavy metal contamination on the outer surface of this silicon single crystal, for example, as shown in Patent Document 1, the flow path of the inert gas is controlled by the structure inside the furnace, and the gas flow rate and the pressure inside the furnace are controlled. It has been proposed to reduce the amount of metal impurities in the atmosphere around the raised crystal by controlling. Further, Patent Document 2 proposes a method of preventing Fe contamination by applying a high-purity coating treatment to the surface of a rectifying cylinder installed in a furnace. Further, Patent Document 3 proposes a method of preventing Fe contamination by providing a quartz cylinder inside the rectifying cylinder.

WO2005-019506 WO2001-081661 Japanese Unexamined Patent Publication No. 2007-314375

However, even if the above-mentioned various measures are taken, in the wafer cut out from the crystal pulled up immediately after the replacement of the HZ component, defects due to Fe contamination such as a decrease in lifetime still occur in the peripheral portion. Therefore, it has been desired to reliably prevent Fe contamination around the crystal even in the crystal produced immediately after replacing the HZ component.

On the other hand, impurities of HZ parts such as heat shield cylinders, heat shield cylinder heat insulating materials and heat absorption cylinders arranged around a single crystal have been reduced, and in the case of graphite parts (graphite parts), the Fe concentration is 0.05 ppm. Hereinafter, in the case of carbon fiber parts (insulation material parts), those having an Fe concentration of 0.5 ppm or less are used, but if the purity of HZ parts is made higher than the current level, the cost will increase significantly and industrial mass production will occur. Not suitable for.

Further, in order to prevent the amount of impurities from being deteriorated after wafer processing even if the metal impurities in the atmosphere around the pulled crystal diffuse from the outer surface of the single crystal, it can be improved by always increasing the crystal diameter, but the cylinder from the asgrown crystal. The amount of grinding increases, the loss of raw materials increases, and the yield of raw materials deteriorates.

As described above, it has been desired to reduce heavy metal contamination on single crystals at the impurity concentration level of the current HZ components.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a silicon single crystal that suppresses Fe contamination of the outer peripheral portion of a single crystal that may occur due to replacement of HZ parts.

The present invention has been made to achieve the above object, and after pulling a silicon single crystal from a silicon melt contained in a crucible by a CZ method using a manufacturing apparatus equipped with HZ parts, the silicon single crystal is used. This is a method for manufacturing a silicon single crystal in which a crystal is cylindrically ground to the product diameter. The correlation between the amount of grinding of the cylindrically ground and the Fe concentration in the peripheral portion of the silicon single crystal at the grinding amount is obtained in advance, and based on the correlation, the peripheral portion of the silicon single crystal having the product diameter is used. Provided is a method for producing a silicon single crystal in which the as-grown diameter of the silicon single crystal to be pulled up is controlled so that the Fe concentration becomes a cylindrical grinding amount equal to or less than a target Fe concentration.

With such a method, Fe contamination on the outer peripheral portion of the silicon single crystal, which may occur when the HZ component is replaced, can be suppressed.

At this time, the Fe concentration of the HZ component is preferably 0.05 ppm or less in the case of the graphite component and 0.5 ppm or less in the case of the carbon fiber component.

By doing so, it is possible to use a component having the same purity as the current HZ component, it is not necessary to purify the HZ component more than necessary, and a silicon single crystal in which Fe contamination is suppressed without increasing the cost can be obtained. Can be manufactured.

At this time, it is preferable that the target Fe concentration in the peripheral portion of the silicon single crystal having the product diameter is 5.0 × 10 ⁹ atoms / cm ^{3 or less.}

In this way, it is possible to suppress a decrease in lifetime due to Fe contamination.

At this time, the HZ component located above the surface of the melt is placed on the heat shield cylinder, the heat shield cylinder heat insulating material installed in the heat shield cylinder, and the heat shield cylinder upper part to promote heat absorption from the single crystal being pulled up. It is preferable to use an endothermic cylinder.

Since these HZ components are directly above and surround the silicon single crystal, they have a large influence on the Fe concentration. Therefore, by adopting these HZ components, the temperature gradient in the pulling direction of the single crystal can be made larger, the pulling speed can be made faster, and Fe contamination on the outer periphery of the silicon single crystal can be further suppressed. can.

At this time, after replacing the HZ part with a new one, it is preferable to control the diameter of the as-grown of the straight body portion so as to be raised and thickened by 3 mm or more from the target diameter until the cumulative usage time reaches 100 hours.

By doing so, it is possible to surely increase the asgrown diameter of the silicon single crystal pulled up after replacing the HZ component with a new one, especially while the Fe concentration is high, and efficiently produce a silicon single crystal in which Fe contamination is suppressed. Can be done.

At this time, it is preferable that the product diameter is 300 mm or more.

In the present invention, such a large-diameter silicon single crystal having a low Fe concentration can be produced with high productivity.

As described above, according to the method for producing a silicon single crystal of the present invention, Fe contamination on the outer surface of the single crystal that may occur when replacing HZ parts can be suppressed, and defects due to Fe contamination can be prevented. .. Furthermore, by reducing quality defects, it is possible to reduce raw material loss and improve yield.

It is a figure which shows the measurement result of the depth from the outer surface and Fe concentration of the asgrown crystal when the heat absorption cylinder made of graphite is replaced with a new one, and when the heat absorption cylinder which has been used for 500 hours or more is used. It is sectional drawing which shows the structure of the main part about the example of the single crystal manufacturing apparatus which can be used in this invention. It is a figure which shows the measurement example of the use time of the apparatus in Example, Comparative Example 1 and Comparative Example 2, the transition of a single crystal pulling diameter and Fe concentration. It is a figure which shows the comparison result of the raw material loss weight in Example and Comparative Example 1. The result of Comparative Example 1 was 1.0.

As described above, there has been a demand for a method for producing a silicon single crystal that suppresses Fe contamination on the outer peripheral portion of the crystal, which may occur due to replacement of HZ parts.

As a result of diligent studies to achieve the above object, the present inventor has determined the usage time of the silicon single crystal manufacturing apparatus after replacing the HZ component located above the surface of the silicon melt, and the raised silicon single crystal. We found that there is a correlation between the amount of cylindrically ground ground from the as-grown diameter of the crystal and the Fe concentration around the silicon single crystal at these amounts of grinding, and manufactured a silicon single crystal based on this correlation. By doing so, it was found that Fe contamination on the outer peripheral portion of the single crystal, which may occur due to replacement of HZ parts, can be suppressed, and the present invention has been completed.

That is, in the present invention, a silicon single crystal is pulled up from a silicon melt contained in a pot by a CZ method using a manufacturing apparatus provided with HZ parts, and then the silicon single crystal is cylindrically ground to a product diameter. A crystal manufacturing method, in which the usage time of the device after replacing the HZ component located above the surface of the silicon melt and the amount of cylindrical grinding from the as-grown diameter of the pulled-up silicon single crystal. And, the correlation with the Fe concentration of the silicon single crystal peripheral portion in the grinding amount is acquired in advance, and based on the correlation, the Fe concentration of the peripheral portion of the silicon single crystal of the product diameter is targeted. This is a method for producing a silicon single crystal in which the as-grown diameter of the silicon single crystal to be pulled up is controlled so that the amount of cylindrical grinding is equal to or less than the Fe concentration.

Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 2 is a cross-sectional view showing the structure of a main part of an example of a single crystal manufacturing apparatus that can be used in the present invention. In the single crystal pulling device 100, a quartz crucible 3a and an outer crucible 3b holding the quartz crucible 3a are arranged in the main chamber 1, and these are rotated and moved up and down by the crucible drive mechanism 7 via the rotation support 6. The raw material melt 12 is placed in a quartz crucible 3a and heated by a heater 5 kept warm by a heat insulating cylinder 4. Further, an endothermic cylinder 13, a heat shield cylinder 15, and a heat shield cylinder heat insulating material 14 surrounding the pulled-up single crystal 11 are arranged. Further, the inert gas is supplied from the upper part of the pull chamber 2 and discharged from the exhaust pipe including the pressure adjusting valve mechanism 8 and the vacuum pump 9 provided in the lower part of the main chamber via the periphery of the single crystal 11.

In the production of a single crystal, a seed crystal (not shown) attached to a seed wire 10 suspended from a pull chamber 2 is landed on a raw material melt 12, and the electric power of a heater 5 is controlled to pull up and grow the single crystal 11. do.

In this example, the endothermic cylinder 13, the heat shield cylinder 15, and the heat shield cylinder heat insulating material 14 surrounding the single crystal 11 which is an HZ component receives radiant heat from the single crystal 11 and becomes high in temperature. An inert gas flows between the single crystal 11, the heat absorbing cylinder 13, the heat insulating cylinder 15, and the heat insulating cylinder heat insulating material 14, but one or more of the heat absorbing cylinder 13, the heat insulating cylinder 15, and the heat insulating cylinder heat insulating material 14 may be used. When a new part is replaced, impurities contained in the newly replaced part are released into an inert gas due to high temperature, adhere to and diffuse on the outer surface of the single crystal, and contaminate the single crystal.

Since impurities in the single crystal proceed to the inside by diffusion from the outer surface, the amount of contamination depends on the distance from the outer surface of the crystal, and the amount of contamination on the outer surface is larger than that on the inside.

Next, the correlation acquired in advance in the present invention will be described.

As described above, the longer the usage time of the silicon single crystal manufacturing apparatus after replacing the HZ component, the lower the Fe concentration of the HZ component and the smaller the amount of Fe contamination. Further, as the amount of cylindrical grinding from the as-grown diameter of the pulled-up silicon single crystal increases, the Fe concentration in the peripheral portion of the silicon single crystal after grinding decreases. Therefore, the usage time of the silicon single crystal manufacturing apparatus after replacing the HZ component located above the surface of the silicon melt, the amount of cylindrical grinding from the as-grown diameter of the raised silicon single crystal, and the amount of grinding are used. There is a correlation between the Fe concentration in the periphery of the silicon single crystal. In the present invention, by quantitatively grasping this correlation and utilizing it, a silicon single crystal can be produced more efficiently.

In order to obtain the correlation, the present invention has conducted the study experiments described below, but the present invention is not limited thereto.

<Examination experiment>
In the study experiment, the selection of the target parts, the cumulative usage time after replacing the HZ parts with new ones, the diameter of the asgrown single crystal, the depth from the asgrown single crystal to the product diameter (grinding amount), and the Fe concentration were as follows. I got it like this.

First, one of the HZ parts arranged above the graphite crucible is selected and replaced with a new part whose Fe concentration of the base material has been measured in advance. Other parts were limited to those 500 hours or more after replacement with new ones that did not cause any problems based on the past operation results.

A single crystal was pulled up with this HZ configuration, and the diameter and Fe concentration of the single crystal were first examined every 10 cm of the straight cylinder without performing cylindrical grinding on the pulled up single crystal. From this result, the portion where the Fe concentration on the outer surface of the single crystal ^{exceeded 5.0 × 10 9} atoms / cm ³ was subsequently subjected to cylindrical grinding to make the diameter 1 mm thinner, and the diameter and Fe concentration were measured. Hereinafter, this was repeated while grinding the diameter little by little until the diameter became 297 mm, and the change in Fe concentration in the depth direction from the outer surface of the single crystal was investigated.

As an example in FIG. 1, from the outer surface of an asgrown single crystal when a graphite heat absorbing cylinder having an Fe concentration of 0.026 ppm as a component base material is replaced with a new one and when a heat absorbing cylinder that has been used for 500 hours or more is used. The measurement results of the depth and Fe concentration are shown.

From this result, when the HZ part is replaced with a new one, the Fe concentration on the outer surface of the asgrown single crystal is higher than when it is not replaced. It was found that the Fe concentration in the later block cylinder could be set to the same level as when the new block was not replaced.

Further, different HZ component replacements were repeated to narrow down the HZ components that affect the Fe concentration on the outer surface of the single crystal. As a result, the Fe concentration contained in the HZ component is 0.05 ppm or less in the case of the graphite component and 0.5 ppm or less in the case of the carbon fiber component, which affects the Fe concentration on the outer surface of the single crystal. It was found that the parts were, in particular, a heat shield cylinder, a heat shield cylinder heat insulating material, and a heat absorption cylinder.

In addition, the cumulative time that the single crystal stays in the heat shield cylinder, the heat shield cylinder heat insulating material, and the heat absorption cylinder exceeds 100 hours for the time that affects the Fe concentration on the outer surface of the crystal after replacing the HZ parts under the above conditions. It turned out that it was a period until.

Based on the above results, the usage time of the device after replacing the HZ component located above the surface of the silicon melt, the amount of cylindrical grinding from the as-grown diameter of the raised silicon single crystal, and the amount of grinding at that amount. It was clarified that there is a correlation with the Fe concentration in the periphery of the silicon single crystal.

Therefore, in the method for producing a silicon single crystal according to the present invention, the usage time of the single crystal pulling device after replacing the HZ component located above the surface of the silicon melt and the asgrown diameter of the pulled silicon single crystal are used. The correlation between the grinding amount obtained by cylindrical grinding and the Fe concentration in the periphery of the silicon single crystal at the grinding amount is acquired in advance. The correlation can be obtained, for example, as in the study experiment described above.

The measurement of the Fe concentration in the block cylindrical portion is not particularly limited, but for example, the lifetime measurement in the block cylindrical portion is performed by a BCT-400 device manufactured by Sington Instruments, and after processing into a polished wafer (PW). Fe concentration is measured by the surface photopower effect (SPV) method. Then, the Fe concentration in the block cylindrical portion can be obtained from the correlation between the measurement result of the lifetime in the block cylindrical portion and the measurement result of the Fe concentration after PW processing.

Based on the correlation obtained in advance in this way, the asgrown diameter of the silicon single crystal to be pulled up is controlled so that the Fe concentration contained in the product diameter becomes a cylindrical grinding amount that is equal to or less than the target Fe concentration, and silicon. Manufactures single crystals.

When the HZ component in the chamber is replaced, the pulling diameter of the silicon single crystal is pulled thicker than the predetermined diameter. When processing a silicon single crystal from an asgrown crystal to a block, the part that is thickly pulled up by cylindrical grinding is scraped off to remove the part with a high impurity concentration such as heavy metal diffused from the outer surface of the single crystal, and the outer surface of the block. It is possible to obtain a single crystal in which the amount of diffusion of contaminants such as heavy metals is small. Further, after a predetermined time has elapsed after replacing the HZ component in the chamber, it is possible to reduce the raw material loss by stopping the pulling diameter to be thicker than the predetermined diameter.

The period for thickening the crystal diameter after replacing the HZ parts and the amount of the thickening diameter are the values obtained by the test, and the thermal history and the arrangement of the parts inside the furnace are taken into consideration for the depth at which the contaminants diffuse from the outer surface of the crystal. However, it is preferable to set the degree of thickening of the single crystal to be large in the portion where the diffusion depth is deep in the crystal length direction and to be small in the portion where the diffusion depth is shallow. When the depth at which the contaminants diffuse from the outer surface of the crystal is the same over the entire length of the crystal, the production may be uniformly made thicker over the entire length of the crystal. Further, after the cumulative usage time reaches 100 hours, the asgrown diameter may be returned to the target diameter. In this way, the raw material yield can be improved.

At this time, the Fe concentration of the HZ component is preferably 0.05 ppm or less in the case of the graphite component and 0.5 ppm or less in the case of the carbon fiber component.

If the Fe concentration of the HZ component is equal to or lower than the above concentration, a component having the same purity as the current HZ component can be used, the HZ component does not have to be highly purified, and Fe is not increased by the present invention. It is possible to produce a silicon single crystal with suppressed contamination.

At this time, it is preferable that the target Fe concentration is 5.0 × 10 ⁹ atoms / cm ^{3 or less.}

When the concentration is less than or equal to the Fe concentration as described above, it is possible to suppress a decrease in lifetime due to Fe contamination.

Further, at this time, the HZ component located above the surface of the melt is heat-absorbed from the heat shield cylinder, the heat shield cylinder heat insulating material installed in the heat shield cylinder, and the single crystal arranged above the heat shield cylinder and being pulled up. It is preferable to use a heat absorbing cylinder that promotes the above.

With these components, the temperature gradient in the pulling direction of the single crystal can be made larger, the pulling speed can be made faster, and Fe contamination on the outer peripheral portion of the silicon single crystal can be further suppressed by the present invention. The target HZ component is not limited to the above, but can be applied as long as it is located above the surface of the silicon melt, and is upstream from the surface of the melt in the flow direction of the inert gas. It is placed on the route.

At this time, after replacing the HZ part with a new one, it is preferable to control the diameter of the as-grown of the straight body portion so as to be raised and thickened by 3 mm or more from the target diameter until the cumulative usage time reaches 100 hours.

By doing so, it is possible to increase the asgrown diameter of the silicon single crystal pulled up while the Fe concentration is high after replacing the HZ component with a new one, and the Fe concentration is surely suppressed to efficiently produce the silicon single crystal. can do.

At this time, it is preferable that the product diameter is 300 mm or more.

In particular, in the present invention, it is possible to produce such a large-diameter silicon single crystal having a low Fe concentration with high productivity.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples.

In this example, Fe element of heavy metal was examined as a pollutant. The Fe concentration is measured by the correlation between the result of the lifetime measurement in the block cylindrical part performed by the BCT-400 device manufactured by Sington Instruments and the measurement result of the Fe concentration obtained by measuring the wafer after PW processing by the SPV method. In this evaluation, the lifetime measurement result in the block cylindrical portion was converted into Fe concentration using the above correlation.

(Example)
Based on the correlation obtained in advance in the above-mentioned examination experiment, using the pulling device shown in FIG. 2, only the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 are newly installed as HZ parts, and all other parts are used cumulatively. Those with an time of 100 hours or more were used. The conditions for producing a silicon single crystal are a charge amount of 430 kg, a pulling speed of 0.5 mm / min, an inert gas flow rate of 100 L / min being supplied from the upper part of the pull chamber 2, and a crystal being produced and shielded from the lower part of the main chamber. This was repeated while continuing to use the heat cylinder 15 and the heat shield heat insulating material 14 after replacing them with new ones. The Fe concentration of the attached new part is 0.04 ppm in the heat shield cylinder 15 and 0.28 ppm in the heat shield cylinder heat insulating material 14. As for the diameter of the asgrown crystal, a single crystal having a diameter of 308 mm, which is 3 mm thicker than the target diameter (reference diameter) of 305 mm, was pulled up. The single crystal produced under the above conditions was cylindrically ground to a diameter of 301 mm with a grinding allowance of 3.5 mm. Further, after the cumulative usage time of the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 has elapsed for 100 hours, the pull-up diameter of the single crystal is returned to the reference diameter of 305 mm.

(Comparative Example 1)
Using the pulling device shown in FIG. 2, only the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 were newly installed as the HZ parts, and the other HZ parts used had a cumulative usage time of 100 hours or more.
The conditions for producing a silicon single crystal are a charge amount of 430 kg, a pulling speed of 0.5 mm / min, an inert gas flow rate of 100 L / min being supplied from the upper part of the pull chamber 2, and a crystal being produced and shielded from the lower part of the main chamber. This was repeated while continuing to use the heat cylinder 15 and the heat shield heat insulating material 14 after replacing them with new ones. The Fe concentration of the attached new part is 0.04 ppm in the heat shield cylinder 15 and 0.22 ppm in the heat shield cylinder heat insulating material 14. The single crystal pulling was continued while keeping the crystal diameter as the reference diameter of 305 mm. The single crystal produced under the above conditions was cylindrically ground to a diameter of 301 mm with a grinding allowance of 2.0 mm.

(Comparative Example 2)
Using the pulling device shown in FIG. 2, all HZ parts including the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 were used with a cumulative usage result of 100 hours or more. The silicon single crystal production conditions were a charge amount of 430 kg, a pulling speed of 0.5 mm / min, an inert gas flow rate of 100 L / min was supplied from the upper part of the pull chamber 2, and crystal production was repeated in a state of being discharged from the lower part of the main chamber. The single crystal pulling was continued while keeping the crystal diameter as the reference diameter of 305 mm. The single crystal produced under the above conditions was cylindrically ground to a diameter of 301 mm with a grinding allowance of 2.0 mm.

FIG. 3 is a transition graph in which the Fe concentration in the crystal of the cylindrical portion was measured for a single crystal after cylindrical grinding manufactured under the conditions of the above three examples. It is shown as the transition of usage time for each condition.

As is clear from FIG. 3, in Comparative Example 1, the Fe concentration increased after the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 were replaced with new ones, but in the example of the present invention, the Fe concentration did not increase. Even when Comparative Example 2 is compared with the present invention, no increase in Fe element is observed due to the replacement of the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 with new ones. On the other hand, in Comparative Example 1, after the heat shield cylinder 15 and the heat shield cylinder heat insulating material 14 were replaced with new ones, a rapid increase in the Fe element was observed, and the cumulative usage time continued until reaching 100 hours.

FIG. 4 is a graph showing a comparison of raw material losses, and the result of Comparative Example 1 was 1.0. In the method of Comparative Example 1, poor SPV quality of the product occurred. On the other hand, in the examples, the SPV quality of the product did not deteriorate, and the raw material loss could be reduced to about one-fifth as compared with the comparative example 1.

As described above, according to the method for producing a silicon single crystal of the present invention, Fe contamination on the outer periphery of the crystal, which may occur when replacing HZ parts, can be suppressed. Furthermore, by reducing quality defects, we were able to reduce raw material loss.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

1 ... Main chamber, 2 ... Pull chamber, 3a ... Quartz crucible,
3b ... Outer crucible, 4 ... Heat insulation tube, 5 ... Heater, 6 ... Rotating support,
7 ... Crucible drive mechanism, 8 ... Pressure adjustment valve mechanism, 9 ... Vacuum pump,
10 ... Seed wire, 11 ... Single crystal, 12 ... Raw material melt, 13 ... Endothermic cylinder,
14 ... Heat shield tube heat insulating material, 15 ... Heat shield tube, 100 ... Single crystal pulling device.

Claims (6)

This is a method for manufacturing a silicon single crystal in which a silicon single crystal is pulled up from a silicon melt contained in a crucible by a CZ method using a manufacturing apparatus equipped with HZ parts, and then the silicon single crystal is cylindrically ground to the product diameter. hand,
The usage time of the device after replacing the HZ component located above the surface of the silicon melt, the amount of cylindrically ground from the as-grown diameter of the pulled-up silicon single crystal, and the said amount at the amount of grinding. Obtain the correlation with the Fe concentration around the silicon single crystal in advance,
Based on the correlation, the asgrown diameter of the silicon single crystal to be pulled up is controlled so that the Fe concentration in the peripheral portion of the silicon single crystal of the product diameter becomes a cylindrical grinding amount that is equal to or less than the target Fe concentration. A method for producing a silicon single crystal. The method for producing a silicon single crystal according to claim 1, wherein the Fe concentration of the HZ component is 0.05 ppm or less in the case of a graphite component and 0.5 ppm or less in the case of a carbon fiber component. The silicon single crystal according to claim 1 or 2, wherein the target Fe concentration in the peripheral portion of the silicon single crystal having the product diameter is 5.0 × 10 ⁹ atoms / cm ^{3 or less.} Production method. The HZ component located above the surface of the melt is placed on the heat shield cylinder, the heat shield cylinder heat insulating material installed in the heat shield cylinder, and the heat absorption from the single crystal which is arranged on the upper part of the heat shield cylinder and is being pulled up. The method for producing a silicon single crystal according to any one of claims 1 to 3, wherein the endothermic cylinder is used to promote the heat absorption. 1. Item 8. The method for producing a silicon single crystal according to any one of Items 4. The method for producing a silicon single crystal according to any one of claims 1 to 5, wherein the product diameter is 300 mm or more.

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