JP6451478B2 - Method for producing silicon single crystal - Google Patents

Description

  The present invention relates to a method for producing a silicon single crystal, and more particularly to a method for producing a silicon single crystal that can suppress the occurrence of dislocations as compared with the conventional case.

  A silicon wafer used as a substrate of a semiconductor device is manufactured by thinly slicing a silicon single crystal ingot and finally cleaning it through a surface grinding (lapping) process, an etching process and a mirror polishing (polishing) process. In general, a silicon single crystal having a large diameter of 300 mm or more is produced by a Czochralski (CZ) method.

  FIG. 1 shows an example of a general apparatus for producing a silicon single crystal by the CZ method. The silicon single crystal manufacturing apparatus 100 shown in this figure is composed of a chamber 11 at its outer periphery, and a crucible 12 is disposed at the center thereof. The crucible 12 has a double structure, is composed of an inner quartz crucible 12a and an outer graphite crucible 12b, and is fixed to the upper end portion of a rotary lifting shaft 13 that can rotate and lift.

  A resistance heating type heater 14 surrounding the crucible 12 is disposed outside the crucible 12, and a heat insulating material 20 is disposed along the inner surface of the chamber 11 outside the crucible 12. Further, above the crucible 12, a pulling shaft 15 such as a wire that is coaxial with the rotary lift shaft 13 and rotates at a predetermined speed in the reverse direction or in the same direction is disposed, and a seed crystal attached to the lower end of the pulling shaft 15. The seed crystal S is held by the holder 16.

  In the chamber 11, a cylindrical heat shield 19 surrounding the silicon single crystal ingot I being grown is disposed above the crucible 12. The heat shield 19 diffuses heat from the silicon melt M in the crucible 12, the heater 14, and the side wall of the crucible 12, and heat diffusion in the vicinity of the crystal growth interface with respect to the growing ingot I. The amount is adjusted, and plays a role of controlling the temperature gradient in the direction of the pulling shaft 15 in the central portion and the outer peripheral portion of the silicon single crystal ingot I.

  A gas introduction port 17 for introducing an inert gas such as Ar gas into the chamber 11 is provided at the upper portion of the chamber 11. In addition, an exhaust port 18 that sucks and discharges gas in the chamber 11 by driving a vacuum pump (not shown) is provided below the chamber 11. The inert gas introduced into the chamber 11 from the gas inlet 17 descends between the growing silicon single crystal ingot I and the heat shield 19, and the lower end of the heat shield 19 and the silicon melt M liquid. After passing through the gap with the surface, it flows toward the outside of the heat shield 19 and further toward the outside of the crucible 12, and then descends outside the crucible 12 and is discharged from the exhaust port 18.

  Using this single crystal manufacturing apparatus 100, in a state where the inside of the chamber 11 is maintained in an Ar gas atmosphere under reduced pressure, a silicon raw material such as polycrystalline silicon filled in the crucible 12 is melted by heating of the heater 14, and silicon fusion Liquid M is formed. Next, the pulling shaft 15 is lowered to deposit the seed crystal S into the silicon melt M, and while the crucible 12 and the pulling shaft 15 are rotated in a predetermined direction, the pulling shaft 15 is pulled upward, Develop Ingot I. During the production of the silicon single crystal, the chamber 11 is cooled to cool the ingot I.

In the above method, when the seed crystal S is deposited on the silicon melt M, dislocations are generated in the seed crystal S due to thermal shock caused by the temperature difference between the seed crystal S and the silicon melt M. When the dislocations growing a silicon single crystal ingot I in the state that occurred, the dislocation to the cylindrical body portion I _b of the grown ingot I will be extended. For this reason, it is important to completely remove the dislocations in the seed crystal S to make them dislocation-free so that the dislocations do not extend into the pulled ingot I.

To prevent extension of the dislocation to such a silicon single crystal, the number diameter of the crystal to be grown from the seed crystal S immediately after the initiation of pulling-up mm (e.g., 3 mm) to form a neck portion I _n which narrowed to a degree dislocation However, after forming the shoulder portion I _s is gradually increasing crystal diameter, growing the straight body portion I _b having a predetermined diameter, often producing a silicon single crystal by a so-called dash's neck method (e.g., Non-patent document 1).

This Dash neck method, diameter of several mm (for example, 3 mm) to form a neck portion I _n of, but removing the dislocations by uniform temperature distribution in the radial direction of the neck portion I _n, the diameter of the crystal in the case of more than 300mm is the neck portion I _n a diameter of several order of mm as described above, the strength to support the weight of the crystals is insufficient to raise the fear that the neck portion I _n during growth of the crystal falls ruptured There is. Therefore, when growing a silicon crystal 300mm, it is necessary to increase the diameter of the neck portion I _n. However, the Dash's neck method, when the diameter of the neck portion I _n exceeds 5 mm, it becomes difficult to equalize the temperature in the radial direction of the neck portion I _n, to dislocation-free by eliminating the generated dislocation It becomes difficult.

Under this background, Patent Document 1, as a technique for dislocation-free crystals even if the diameter of the neck portion I _n exceeds 5 mm, an auxiliary heater capable of heating surrounding the seed crystal S A silicon single crystal manufacturing apparatus is described. FIG. 2 shows a silicon single crystal manufacturing apparatus 1 described in Patent Document 1. In this figure, the same components as those in FIG. The apparatus 1 shown in FIG. 2 includes an auxiliary heater 21 that can surround and heat the seed crystal S (and the neck portion I _n ). The auxiliary heater 21 includes a heat generating portion 21a that surrounds and heats the seed crystal S (and the neck portion I _n ), and a moving mechanism 21b that moves the heat generating portion 21a forward and backward.

Auxiliary heater 21 in the silicon single crystal device 1, when forming the neck portion I _n by pulling the seed crystal S was Chakueki the silicon melt M, by heating the neck portion I _n, the neck portion I _n diameter is it possible to dislocation-free by removing the dislocations generated in the neck portion I _n even if it exceeds 5 mm. In addition, by preheating the seed crystal S before landing on the silicon melt M, the thermal shock caused by the temperature difference between the seed crystal S and the silicon melt M at the time of landing is reduced, thereby generating dislocations. It can also be suppressed.

JP 2004-315249 A

W. C. Dash, J. et al. Appl. Phys. Vol. 30, no. 4 (1959), p. 459-473

However, even when a silicon single crystal is manufactured using the apparatus 1 described in Patent Document 1, dislocations may still occur in the manufactured single crystal silicon.
Accordingly, an object of the present invention is to propose a method for producing a silicon single crystal that can suppress the occurrence of dislocations as compared with the conventional art.

The inventors of the present invention have intensively studied how to solve the above problems. For this purpose, first, in order to investigate the cause of the occurrence of dislocations in the silicon single crystal produced by the apparatus described in Patent Document 1, the silicon single crystal where dislocations occurred was investigated in detail. As a result, increase in the diameter of the neck portion I _n that seems to be due to the retraction of the auxiliary heater 21 was confirmed.

That is, in the the apparatus 1 described in Patent Document 1, the auxiliary heater 21 is disposed so as to surround the seed crystal S, a crystal is grown by pulling a seed crystal S while heating the seed crystal S and the neck portion I _n but the inside of the auxiliary heater 21 does not have a size to pass the shoulder portion I _s and the straight body portion I _b followed neck I _n. Therefore, before the formation of the shoulder portion I _s (i.e., during formation of the neck portion I _n), although the auxiliary heater 21 must be retracted to a position not to interfere with the pulling of the silicon single crystal, the auxiliary heater 21 than is the diameter of the neck portion I _n has been found that in some cases increased during the saving.

The present inventors have found that a transmission electron microscope (Transmission Electron Microscope, TEM) further results of investigation using a dislocation increase in the neck portion _{I n} diameter (the expanded diameter portion) as a starting point occurs, it generated dislocation It has also been found that extends to the straight body _Ib of the silicon single crystal.

The present inventors have found that an increase in the diameter of the neck portion I _n the solid-liquid interface between the silicon melt M and the neck portion I _n is rapidly cooled by having retracted the auxiliary heater 21, such the rapid It was inferred that the cooling (temperature change) occurred because the adjustment of the heater 14 disposed around the crucible 12 could not be sufficiently absorbed. That is, since there is a time lag in the temperature control of the solid-liquid interface by the heater 14, it is difficult to instantaneously absorb a sudden temperature change at the solid-liquid interface by controlling the heater 14 around the crucible 12.

Therefore, a result of intensive studies for suppressing ways to increase the diameter of the neck portion I _n by suppressing the rapid temperature changes in the solid-liquid interface between the silicon melt M and the neck portion I _n, Chakueki the silicon melt M It was found that it is extremely effective to raise the auxiliary heater 21 and / or reduce the output of the auxiliary heater 21 before pulling up the seed crystal S, and the present invention has been completed. .

That is, the gist of the present invention is as follows.
(1) A crucible filled with a silicon raw material, a heater that heats and melts the silicon raw material in the crucible to form a silicon melt, and a seed crystal that is poured into the silicon melt Using a single crystal silicon manufacturing apparatus provided with an auxiliary heater capable of heating the seed crystal, the seed crystal was applied to the silicon melt while being heated by the auxiliary heater, and the liquid was applied. In the method for producing a silicon single crystal by pulling up the seed crystal to form a neck portion, the seed crystal is deposited on the silicon melt without melting the seed crystal before the deposition, A method for producing a silicon single crystal, wherein the auxiliary heater is raised or / and the output of the auxiliary heater is reduced before pulling up the seed crystal.

(2) The silicon according to (1), wherein the auxiliary heater is raised such that the height of the auxiliary heater after the elevation is 30 mm or more and 100 mm or less from the liquid surface of the silicon melt. A method for producing a single crystal.

(3) The silicon according to (2), wherein the auxiliary heater is raised so that the height position of the auxiliary heater after the elevation is 50 mm or more and 100 mm or less from the surface of the silicon melt. A method for producing a single crystal.

(4) The output of the auxiliary heater is reduced so that the output of the auxiliary heater after the output reduction is 50% or less with respect to the output before the seed crystal is deposited on the silicon melt. The method for producing a silicon single crystal according to any one of (1) to (3).

(5) The output of the auxiliary heater is reduced so that the output of the auxiliary heater after the reduction of the output is 20% or less with respect to the output before the seed crystal is deposited on the silicon melt. (1) The method for producing a silicon single crystal according to (4).

(6) The silicon single crystal according to any one of (1) to (5), wherein the auxiliary heater is raised and the output of the auxiliary heater is reduced before the seed crystal is pulled up. Manufacturing method.

(7) The auxiliary heater is raised to a height position of 30 mm or more and 50 mm or less from the surface of the silicon melt, and the output of the auxiliary heater is set before the seed crystal is deposited on the silicon melt. The method for producing a silicon single crystal according to (6), which is reduced to 50% or less with respect to the output.

(8) The method for producing a silicon single crystal according to any one of (1) to (7), wherein a diameter of the neck portion is 6 mm or more.

  According to the present invention, in order to raise the auxiliary heater or / and reduce the output of the auxiliary heater before pulling up the seed crystal deposited on the silicon melt to form the neck portion, Since a rapid temperature drop at the solid-liquid interface between the silicon melt and the neck portion due to retraction can be suppressed, the formation of dislocations in the silicon single crystal to be manufactured can be suppressed.

It is a figure which shows an example of the general apparatus which manufactures a silicon single crystal by the Czochralski method. It is a figure which shows the silicon single crystal manufacturing apparatus described in patent document 1. FIG.

  Hereinafter, embodiments of the present invention will be described. A method for producing a silicon single crystal according to the present invention comprises: a crucible filled with a silicon raw material; a heater that heats and melts the silicon raw material in the crucible to form a silicon melt; and a seed crystal that is deposited in the silicon melt. Using a single crystal silicon manufacturing apparatus equipped with an auxiliary heater capable of heating the seed crystal by surrounding the seed crystal, the seed crystal was applied to the silicon melt while being heated by the auxiliary heater, and the liquid was applied. This is a method for producing a silicon single crystal by pulling up a seed crystal to form a neck portion. Here, it is important to raise the auxiliary heater or / and reduce the output of the auxiliary heater before raising the seed crystal.

  In the present invention, a silicon single crystal is manufactured by forming a neck portion, and the seed crystal (and the neck portion) can be surrounded and heated so that dislocation can be eliminated even when the diameter of the neck portion is large. It is premised on using a silicon single crystal manufacturing apparatus equipped with a simple auxiliary heater. As such an apparatus, for example, the apparatus 1 described in Patent Document 1 shown in FIG. 2 can be used. Hereinafter, the present invention will be described in detail by taking the case where the apparatus 1 shown in FIG. 2 is used as an example.

  First, while rotating the crucible 12 and the pulling shaft 15 in a predetermined direction, the seed crystal S attached to the seed crystal holder 16 is lowered to just above the silicon melt M to preheat the seed crystal S.

  As the seed crystal S, a silicon single crystal having a cylindrical shape or a polygonal column shape can be used. By reducing the diameter (cross-sectional area) of the seed crystal S, it becomes easier to change the temperature when the seed crystal S is deposited on the silicon melt M, so that the temperature distribution in the radial direction at the time of landing is more uniform. become. As a result, the thermal stress acting on the seed crystal S is reduced, and dislocations introduced into the seed crystal S at the time of landing can be reduced.

  However, when the diameter of the seed crystal S is less than 6 mm, it is difficult to stably support a silicon single crystal having a diameter of about 300 mm and a weight exceeding 300 kg. Therefore, the diameter of the seed crystal S is 6 mm or more. It is preferable to do. On the other hand, when the diameter of the seed crystal 35 exceeds 14 mm, it is difficult to make the temperature distribution in the radial direction uniform even if the auxiliary heater 21 is used, and it is difficult to remove dislocations generated in the seed crystal S. become. Therefore, the diameter of the seed crystal S is preferably 14 mm or less.

  The distance between the silicon melt M and the tip of the seed crystal S during preheating is preferably 1 to 30 mm. In order to bring the temperature of the tip of the seed crystal S as close as possible to the surface temperature of the silicon melt M, More preferably, it is 5 mm or less. The preheating time is preferably about 5 to 60 minutes. Thereby, the temperature of the front-end | tip part of the seed crystal S can be set to about 1200-1300 degreeC, and the temperature difference of the front-end | tip part of the seed crystal S and the silicon melt M can be reduced.

  After the preheating, it is preferable that the tip portion of the seed crystal S is further heated by the heat generating portion 21a of the auxiliary heater 21 to raise the temperature of the tip portion of the seed crystal S to 1380 to 1420 ° C. If the temperature of the tip portion of the seed crystal S is 1380 ° C. or higher, when the seed crystal S is lowered and the tip portion is deposited on the silicon melt M, the tip portion of the seed crystal S and the silicon melt M The thermal stress resulting from the temperature difference can be reduced and the occurrence of dislocation can be further suppressed. On the other hand, if the temperature of the tip portion of the seed crystal S exceeds 1420 ° C., the seed crystal S may be melted and blown when the seed crystal S is deposited on the silicon melt M. For these reasons, the temperature at the tip of the seed crystal S is preferably 1380 to 1420 ° C. This can be performed by setting the output of the auxiliary heater 21 to 60% or more and 95% or less of the output at which the seed crystal S is dissolved.

  Next, the seed crystal S is lowered by the pulling shaft 15 so that the tip of the seed crystal S is deposited on the silicon melt M. Since the difference between the temperature of the tip portion of the seed crystal S and the temperature of the silicon melt M is reduced by the heating by the auxiliary heater 21 at the time of the liquid deposition, the heat generated in the seed crystal S is reduced. The stress is small, and dislocations can be prevented from occurring in the seed crystal S.

As described later, in the present invention, before forming the neck portion I _n by pulling the seed crystal S was Chakueki raise the auxiliary heater 21, and / or to reduce the output of the auxiliary heater 21 . Therefore, as compared with the conventional method described in Patent Document 1, it reduced the temperature of the neck portion I _n at the neck portion I _n formation, possibly dislocation reduction effect by the heating of the auxiliary heater 21 is reduced is there. Therefore, it is preferable to raise the temperature of the silicon melt M higher than usual so as to compensate for the temperature drop due to the rise of the auxiliary heater 21 and the reduction of the output.

Then, usually, by pulling the seed crystal S held by the seed crystal holder 16 by pulling axis 15, is grown a silicon crystal to form a neck portion I _n the tip of the seed crystal S, in the present invention Before that, the auxiliary heater 21 is raised or / and the output of the auxiliary heater 21 is reduced. As described above, when producing a silicon single crystal using the apparatus 1 shown in FIG. 2, the rapid cooling of the solid-liquid interface between the silicon melt M and the neck portion I _n caused by retraction of the auxiliary heater 21 As a result, dislocations may occur in the produced silicon single crystal.

The present inventors have found that in order to prevent rapid cooling in the solid-liquid interface between the silicon melt M and the neck portion I _n as described above, before forming the neck portion I _n, increasing the auxiliary heater 21 I thought of making it. In other words, before forming the neck portion I _n, by increasing the auxiliary heater 21, when retracts the auxiliary heater 21 before the formation of the shoulder portion I _s, the silicon melt M and the neck portion I _n A rapid temperature change at the interface can be suppressed.

  It is preferable to raise the auxiliary heater 21 so that the height position of the auxiliary heater 21 after the rise is 30 mm or more and 100 mm or less from the surface of the silicon melt M. As shown in the examples described later, by setting the height position of the auxiliary heater 21 after rising within the above range, the success rate of dislocation elimination in the manufactured silicon single crystal can be 80% or more. More preferably, it is 50 mm or more and 100 mm or less, and in this case, the success rate of dislocation elimination can be made 100%.

In the present specification, the “height position of the auxiliary heater” means a distance between the lowermost part of the auxiliary heater 21 and the silicon melt M, and is indicated by a symbol G in FIG. ing. Further, in a normal silicon single crystal manufacturing apparatus, when the auxiliary heater 21 is retracted to a position that does not hinder the pulling of the silicon single crystal, the auxiliary heater 21 is moved in the horizontal direction due to the apparatus configuration. It is difficult. Therefore, it will be retracted by raising in an oblique direction with respect to the vertical direction or the vertical direction, when raising obliquely auxiliary heater 21 with respect to the vertical direction, at least a portion of the neck portion I _n is remained in the auxiliary heater 21, the presence of the auxiliary heater 21, to suppress the heat radiation in the vicinity of the solid-liquid interface between the silicon melt M and the neck portion I _n, suppress an abrupt cooling of the solid-liquid interface To do.

The effect of raising the auxiliary heater 21 can also be achieved by reducing the output of the auxiliary heater 21. That is, when reducing the output of the auxiliary heater 21, the temperature of the solid-liquid interface between the silicon melt M and the neck portion I _n is decreased, when retracting the auxiliary heater 21 before the formation of the shoulder portion I _s Rapid cooling at the solid-liquid interface can be suppressed.

  At that time, the output of the auxiliary heater 21 is reduced so that the output of the auxiliary heater 21 after the output reduction is 50% or less with respect to the output before the seed crystal S is deposited on the silicon melt M. It is preferable to carry out. As shown in the examples described later, by setting the above range, the success rate of dislocation elimination can be 80% or more. More preferably, it is 20% or less. In this case, the success rate of dislocation elimination can be made 100%.

Incidentally, the present invention is also included the case where the output of the auxiliary heater 21 to 0%, also in this case, achieve a uniform effect of the temperature distribution in the radial direction of the neck portion I _n the auxiliary heater 21 be able to. That is, since the chamber 11 of the apparatus 1 is cooled as described above, when the auxiliary heater 21 is retracted, the silicon single crystal ingot I is rapidly cooled.

Under such circumstances, to surround the heat generating portion 21a of the auxiliary heater 21 is disposed so as to surround the neck portion I _n, be an output of 0% of the auxiliary heater 21, a neck portion I _n heating part 21a suppresses the cooling of the neck portion I _n, it is possible to achieve the effect of uniform temperature distribution in the radial direction of the neck portion I _n. As shown in the examples described later, even when the output of the auxiliary heater 21 is set to 0%, the success rate of non-dislocation can be set to 100%.

  Such raising of the auxiliary heater 21 and reduction of the output can be performed not only independently but also in combination. In this case, the auxiliary heater 21 is raised to a height position of 30 mm or more and 50 mm or less from the liquid surface of the silicon melt M, and the output of the auxiliary heater 21 is set before the seed crystal S is deposited on the silicon melt M. It is preferable to reduce the output to 50% or less. Thereby, the success rate of dislocation elimination can be made 100%.

Thereafter, the seed crystal S held in the seed crystal holder 16 is pulled up by the pulling shaft 15, and a silicon single crystal is grown on the tip of the seed crystal S. Under this case, by pulling the pulling axis 15 at a speed higher than the pulling speed in forming a cylindrical body portion I _b to be described later, the growth interface of silicon single crystal ingot I, i.e. the shape of the front end face of the neck portion I _n as a convex shape to form a neck portion I _n.

In the device 1 used in the present invention, the heat generating portion 21a of the auxiliary heater 21 for heating the neck portion I _n, can be realized even dislocation-free when the diameter of the neck portion I _n is large. In terms of producing a silicon crystal of 300mm or more large diameter, the diameter of the neck portion I _n is preferably at least 6 mm. Further, if the diameter of the neck portion I _n exceeds 12mm, even if with a heated by the auxiliary heater 21, since the planar heat distribution of the neck I _n is difficult to obtain, the thermal stress increases, neck dislocation-free parts I _n becomes difficult. For these reasons, the diameter of the neck portion _{I n} is preferably set to 12mm or less.

Subsequently, by stopping the supply of power to the auxiliary heater 21, after the heat generating portion 21a is retracted from the periphery of the neck portion I _n, is grown silicon single crystal ingot I to a predetermined diameter, a shoulder portion I After forming _s , the silicon single crystal ingot I is pulled up at a predetermined pulling rate to form the straight body portion _Ib , and a silicon single crystal can be manufactured while suppressing the occurrence of dislocations as compared with the conventional case.

(Invention Examples 1 to 11)
Examples of the present invention will be described below. Silicon single crystals according to Invention Examples 1 to 11 were manufactured using the apparatus 1 shown in FIG. Specifically, first, the crucible 12 (diameter: 32 inches) is filled with polycrystalline silicon, which is a raw material for silicon crystals, and a cylindrical silicon single crystal (diameter: 10 mm) is used as the seed crystal S in the seed crystal holder 16. ) Was attached. Next, Ar gas was flowed into the chamber 11 to make the inside of the chamber 11 an Ar atmosphere, and then the polycrystalline silicon in the crucible 12 was melted by the heater 14 to obtain a silicon melt M. Subsequently, while rotating the crucible 12 and the pulling shaft 15 in directions opposite to each other at 6 rpm and 1 rpm, the seed crystal S attached to the seed crystal holder 16 is lowered to the position just above the silicon melt M, and the pulling shaft 15 causes the seed crystal S to drop. The seed crystal S attached to the crystal holder 16 was lowered from the surface of the silicon melt M to a height position of 5 mm, held for 30 minutes, and preheated. Subsequently, the seed crystal S was preheated for another 30 minutes by the auxiliary heater 21 arranged at a height of 20 mm from the surface of the silicon melt. The output of the auxiliary heater 21 at that time was 90% of the output at which the seed crystal S starts to dissolve. Next, the seed crystal S was lowered by the pulling shaft 15 and deposited on the silicon melt M, and held for 10 minutes. Thereafter, as shown in Table 1, the auxiliary heater 21 is raised to the height position shown in Table 1 and / or the output of the auxiliary heater 21 is reduced to the output shown in Table 1, and then the pulling speed 2 pulling in .0mm / min, diameter: after forming the neck portion _{I n} of 8 mm, gradually lowering the pulling rate to form a shoulder portion _{I s,} a straight body portion Ib at a pulling speed of 0.5 mm / min form Then, silicon crystals according to Invention Examples 1 to 11 were formed.

(Conventional example)
Using the apparatus 1 shown in FIG. 2, a silicon single crystal according to a conventional example was manufactured. At that time, the height position and the output of the auxiliary heater 21 is set to the values shown in Table 1, addition, before forming the neck portion I _n by pulling the seed crystal S was Chakueki, Ya rise of the auxiliary heater 21 The output was not reduced. Other conditions are the same as those of Invention Example 1.

<Evaluation of dislocation-free rate>
For each of Invention Examples 1 to 11 and the conventional example, silicon crystals were produced 10 times under the respective conditions, and the dislocation-free rate at which dislocations did not occur in the produced silicon single crystal was evaluated. The obtained results are shown in Table 1. As is clear from Table 1, it can be seen that the dislocation-free rate is increased by increasing the auxiliary heater or / and reducing the output of the auxiliary heater. In particular, it can be seen that the success rate of non-dislocation is 100% by raising the auxiliary heater to a height position of 50 mm or more and 100 mm or less, or by making the output of the auxiliary heater 20% or less. Similarly, when the auxiliary heater is raised and the output of the auxiliary heater is reduced, the auxiliary heater is raised to a height position of 30 mm or more and 50 mm or less from the surface of the silicon melt, and the auxiliary heater is used. It can be seen that the dislocation-free rate becomes 100% by reducing the output of 50% or less to the output before the seed crystal is deposited on the silicon melt.

  According to the present invention, in order to raise the auxiliary heater or / and reduce the output of the auxiliary heater before pulling up the seed crystal deposited on the silicon melt to form the neck portion, This is useful in the semiconductor industry because it can suppress a rapid temperature drop at the solid-liquid interface between the silicon melt and the neck portion due to retraction, and can suppress the formation of dislocations in the single crystal silicon to be manufactured.

DESCRIPTION OF SYMBOLS 1,100 Silicon single crystal manufacturing apparatus 11 Chamber 12 Crucible 12a Quartz crucible 12b Graphite crucible 13 Rotating lift shaft 14 Heater 15 Lifting shaft 16 Seed crystal holder 17 Gas inlet 18 Exhaust outlet 19 Thermal shield 20 Heat insulating material 21 Auxiliary heater 21a Heat generation part 21b Movement mechanism I Silicon single crystal ingot I _N neck part I _s shoulder part I _b Straight body part S Seed crystal M Silicon melt

Claims (8)

A crucible filled with a silicon raw material, a heater that heats and melts the silicon raw material in the crucible to form a silicon melt, and a seed crystal that is disposed so as to surround a seed crystal that is deposited in the silicon melt. Using a single crystal silicon manufacturing apparatus equipped with an auxiliary heater capable of heating the seed crystal, the seed crystal is applied to the silicon melt while being heated by the auxiliary heater, In the method of manufacturing a silicon single crystal by forming a neck portion by pulling up,
The landing of the seed crystal on the silicon melt is performed without melting the seed crystal before the landing,
A method for producing a silicon single crystal, wherein the auxiliary heater is raised before the seed crystal is pulled or / and the output of the auxiliary heater is reduced.   The production of the silicon single crystal according to claim 1, wherein the raising of the auxiliary heater is performed such that the height position of the auxiliary heater after the raising is 30 mm or more and 100 mm or less from the liquid surface of the silicon melt. Method.   The production of the silicon single crystal according to claim 2, wherein the raising of the auxiliary heater is performed such that the height position of the auxiliary heater after the raising is 50 mm or more and 100 mm or less from the liquid surface of the silicon melt. Method.   The reduction of the output of the auxiliary heater is performed so that the output of the auxiliary heater after the reduction of the output is 50% or less with respect to the output of the seed crystal before landing on the silicon melt. The manufacturing method of the silicon single crystal as described in any one of Claims 1-3.   The reduction of the output of the auxiliary heater is performed so that the output of the auxiliary heater after the reduction of the output is 20% or less with respect to the output before landing of the seed crystal on the silicon melt, The method for producing a silicon single crystal according to claim 4.   The method for producing a silicon single crystal according to any one of claims 1 to 5, wherein the auxiliary heater is raised and the output of the auxiliary heater is reduced before the seed crystal is pulled up.   The auxiliary heater is raised to a height position of 30 mm or more and 50 mm or less from the surface of the silicon melt, and the output of the auxiliary heater is compared with the output before the seed crystal is deposited on the silicon melt. The method for producing a silicon single crystal according to claim 6, wherein the method is reduced to 50% or less.   The method for producing a silicon single crystal according to claim 1, wherein a diameter of the neck portion is 6 mm or more.

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