JP5439972B2 - Manufacturing method of large-diameter silicon single crystal - Google Patents

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for a large-diameter silicon single crystal suitable for use in manufacturing a silicon wafer used for a semiconductor device. More specifically, the present invention relates to a large-diameter silicon single crystal having a diameter of 450 mm or larger. The present invention relates to a technique that can be manufactured at a low cost and in a short time with the same quality as a small-diameter silicon single crystal having a smaller diameter.

  At present, silicon wafers having a diameter of 200 mm or 300 mm are mainly used for semiconductor substrates of semiconductor devices. These silicon wafers are obtained by heating a polycrystalline silicon raw material housed in a crucible with a heater. A silicon single crystal is produced by a so-called Czochralski method (hereinafter abbreviated as CZ method) in which a seed crystal is brought into contact with this silicon melt and pulled up while rotating. Is cut using a wire saw or the like, and then at least one principal surface is mirror-polished (see, for example, Patent Documents 1 and 2).

By the way, in the manufacturing process of a semiconductor device, since the improvement of productivity can be expected by using a silicon wafer having a larger area, a diameter of 450 mm or more is substituted for a small-diameter silicon wafer having a diameter of 200 mm or 300 mm. Accordingly, in connection with the pulling of a silicon single crystal, the pulling of a large-diameter silicon single crystal having a diameter of 450 mm or more is also being studied.
Crystal defects are a problem with this large-diameter silicon single crystal.
As a crystal defect of a silicon single crystal, there is a Grown-in defect that occurs in the cooling process, and as this Grown-in defect, a COP (Crystal Originated Particle) defect (vacancy type) that occurs at 1100 ° C. to 1050 ° C. Defect) There are OSF (Oxidation induced Stacking Fault) defects generated at 1050 ° C. to 900 ° C., and BMD (Bulk Micro Defect) defects generated at 900 ° C. to 600 ° C.

This Grown-in defect is V / G, which is the ratio between the pulling speed V (mm / min) when growing a silicon single crystal and the crystal temperature gradient G (° C./mm) in the pulling axis direction near the solid-liquid interface. It is considered that the amount of vacancies introduced from the solid-liquid interface and the amount of interstitial Si are determined by the (mm ² / ° C./min) value, and this V / G value is the advection of vacancies according to the pulling rate. And the balance of interstitial Si diffusion according to the temperature gradient.
If this V / G value is within an appropriate range, the vacancies introduced from the solid-liquid interface and the interstitial Si combine and disappear while the temperature of the pulled silicon single crystal is high. .

  However, when the V / G value is larger than the appropriate range, the advection of vacancies according to the pulling rate exceeds the diffusion of interstitial Si according to the temperature gradient, and the vacancy concentration becomes high. When vacancy supersaturation occurs due to a temperature drop accompanying the progress of the pulling of the silicon single crystal, a COP defect is detected in the silicon single crystal after the pulling. On the other hand, when the V / G value is smaller than the appropriate range, the advection of vacancies according to the pulling rate is less than the diffusion of interstitial Si according to the temperature gradient, and the interstitial Si concentration becomes high. Interstitial Si supersaturation is caused by a temperature drop accompanying the progress of pulling of the silicon single crystal, and interstitial defects are detected in the silicon single crystal after pulling.

Among the grown-in defects, the COP defect is a deteriorating factor of the initial oxide film breakdown voltage characteristic (GOP) of the silicon wafer, so that it is required to reduce the COP defect density of the silicon single crystal.
In general, a silicon having a low COP defect density that provides a V / G value of 0.2 (mm ² / ° C./min) or more and a sufficient oxide film withstand voltage characteristic in which COP defects are detected in a silicon single crystal after pulling. In order to obtain a single crystal, an appropriate range of the V / G value is 0.2 to 0.4 (mm ² / ° C./min).

JP 2003-160363 A JP-A-8-261831

However, pulling a large-diameter silicon single crystal having a diameter of 450 mm or more has the following various problems in terms of time and manufacturing cost.
Compared with a small-diameter silicon single crystal, a large-diameter silicon single crystal requires a time of 2 to 3 weeks just by pulling up the single crystal, and has a problem that the time required for production is greatly increased. In addition, the large-diameter silicon single crystal requires a larger pulling device than the small-diameter silicon single crystal, and the amount of electric power for operating the pulling device increases, which increases the manufacturing cost. there were.

Therefore, when mass-producing large-diameter silicon single crystals, it is necessary to frequently conduct various tests and inspections for quality improvement for mass production. Because of the cost, it is difficult to frequently perform these various tests and various tests.
Furthermore, there is no inspection device that can handle a large-diameter silicon single crystal for inspection devices such as surface detectors, and the crystal structure and crystal defects of this large-diameter silicon single crystal are equivalent to those of a small-diameter silicon single crystal. There was a problem that it could not be inspected at the standard.

  The present invention has been made in order to solve the above-described problems. A large-diameter silicon single crystal having a diameter of 450 mm or larger is obtained with the same quality as a small-diameter silicon single crystal having a smaller diameter. An object of the present invention is to provide a method and an apparatus for producing a large-diameter silicon single crystal that can be produced at low cost and in a short time.

Method for producing large diameter silicon single crystal according to the present onset Ming is a method for producing large diameter silicon single crystal to grow a large diameter silicon single crystal from a silicon melt contained in a crucible by the Czochralski method,
Wherein is arranged to surround the large diameter silicon single crystal and the crucible Rutotomoni, outer diameter in combination isosamples select one or more thermal insulation pieces from multiple species inner diameter, a plurality of changeable thickness In an apparatus having a heat insulating member , the hot zone is composed of the plurality of heat insulating members, and by optimizing the shape of the hot zone that forms the cooling region above the solid-liquid interface of the large-diameter silicon single crystal,
The thermal history at the time of pulling up the large-diameter silicon single crystal is a crystal defect formation temperature region when cooling the grown small-diameter silicon single crystal having a smaller diameter than the large-diameter silicon single crystal, and the crystal defect formation temperature region. It simulates the thermal history at the time of pulling up the small-diameter silicon single crystal including the staying time, and grows the large-diameter silicon single crystal based on the simulated thermal history.

Apparatus for manufacturing large-diameter silicon single crystal according to the present onset Ming is a manufacturing apparatus of large diameter silicon single crystal to grow a large diameter silicon single crystal from a silicon melt by the Czochralski method,
A crucible for containing the silicon melt, a heating means arranged around the crucible for heating the silicon melt in the crucible, and a pulling means for pulling up the large-diameter silicon single crystal from the silicon melt, A plurality of heat insulating members whose shapes can be changed are disposed so as to surround the large-diameter silicon single crystal and the crucible, each of the plurality of heat insulating members is constituted by a plurality of types of heat insulating pieces, and the plurality of types of heat insulating members Select one kind of heat insulating piece from the pieces, or select two or more kinds of heat insulating pieces, change the outer diameter, inner diameter, and thickness by combining these heat insulating pieces, and the solid-liquid interface of the large-diameter silicon single crystal By selecting the shape of the hot zone that forms the upper cooling region, the thermal history during the pulling of the large-diameter silicon single crystal is reduced to a small-diameter silicon having a smaller diameter than the large-diameter silicon single crystal. It can be set to allow simulating the thermal history during the pulling of the crystal.

According to large diameter method for manufacturing a silicon single crystal according to the present onset bright, by changing a plurality of heat insulating members each having a shape arranged to surround the large diameter silicon single crystal and the crucible, large diameter silicon single crystal The thermal history at the time of pulling up was simulated to the thermal history at the time of pulling up a small-diameter silicon single crystal having a smaller diameter than the large-diameter silicon single crystal, and the large-diameter silicon single crystal was grown based on this simulated thermal history. The thermal history during pulling of the large-diameter silicon single crystal can be easily controlled simply by changing the shape of each of the plurality of heat insulating members.
As a result, a large-diameter silicon single crystal having a diameter of 450 mm or larger can be manufactured with a quality equivalent to that of a small-diameter silicon single crystal having a smaller diameter, and at a low cost and in a short time.

According to the manufacturing method of large-diameter silicon single crystal according to the present onset bright, a plurality of heat insulating members each, select one insulation piece from a plurality of types of insulation pieces or select two or more adiabatic piece Since the shape can be changed by combining these heat insulating pieces, a desired heat insulating piece can be selected from these heat insulating pieces, or by combining them, the thermal history when pulling up the large-diameter silicon single crystal can be obtained. Furthermore, it can be controlled easily.
Thereby, a large-diameter silicon single crystal having a diameter of 450 mm or larger can be manufactured with a quality equivalent to that of a small-diameter silicon single crystal having a smaller diameter and at a lower cost and in a shorter time.

According to the production method of the present onset bright in accordance large diameter silicon single crystal, as a heat history during the pulling of the small-diameter silicon single crystal, the crystal defect formation temperature range at which to cool the grown small diameter silicon single crystal, this Since it includes the residence time in the crystal defect formation temperature region, it is possible to easily control crystal defects, particularly COP defects, in a large-diameter silicon single crystal. Therefore, a large-diameter silicon single crystal in which crystal defects, particularly COP defects are controlled, can be easily manufactured, and it is easy to deal with mass production.

According to the apparatus for manufacturing large-diameter silicon single crystal according to the present onset bright, so as to surround the large diameter silicon single crystal and the crucible, disposing a plurality of heat insulating members can be reshaped, a plurality of heat insulating members each shaped By changing, the thermal history when pulling up the large-diameter silicon single crystal can be simulated to the thermal history when pulling up the small-diameter silicon single crystal having a smaller diameter than the large-diameter silicon single crystal. The thermal history during pulling of the large-diameter silicon single crystal can be easily controlled simply by changing the shape.
As a result, a large-diameter silicon single crystal having a diameter of 450 mm or larger can be manufactured with a quality equivalent to that of a small-diameter silicon single crystal having a smaller diameter, and at a low cost and in a short time.

According to the apparatus for manufacturing large-diameter silicon single crystal according to the present onset bright, or a plurality of heat insulating members each composed of a plurality of types of insulation pieces, and selects one insulation piece from a plurality of kinds of insulation piece Or, by selecting two or more kinds of heat insulating pieces and combining these heat insulating pieces, the shape of each of the plurality of heat insulating members can be changed, so select a desired heat insulating piece from these heat insulating pieces, Alternatively, by combining these, the thermal history during pulling of the large-diameter silicon single crystal can be controlled more easily.
Thereby, a large-diameter silicon single crystal having a diameter of 450 mm or larger can be manufactured with a quality equivalent to that of a small-diameter silicon single crystal having a smaller diameter and at a lower cost and in a shorter time.

It is sectional drawing which shows the manufacturing apparatus of the large diameter silicon single crystal of one Embodiment of this invention. It is a perspective view which shows the block-shaped part of the heat insulation member of the manufacturing apparatus of the large diameter silicon single crystal of one Embodiment of this invention. It is a perspective view which shows the cylindrical part of the heat insulation member of the manufacturing apparatus of the large diameter silicon single crystal of one Embodiment of this invention. It is a fragmentary longitudinal cross-section which shows the defect distribution of the silicon single crystal grown, gradually reducing the pulling speed of the silicon single crystal. It is a cross-sectional view which follows the AA line of FIG. It is a figure which shows the result of having simulated the thermal history at the time of a silicon single crystal pulling. It is a figure which shows the result of having simulated the thermal history after the solidification at the time of a silicon single crystal pulling. It is a figure which shows the magnitude | size of the COP defect corresponding to each thermal history of FIG.

The form for implementing the manufacturing method and manufacturing apparatus of the large diameter silicon single crystal of this invention is demonstrated.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

FIG. 1 is a cross-sectional view showing an apparatus for producing a large-diameter silicon single crystal according to an embodiment of the present invention, in which a large-diameter silicon single crystal is grown from a silicon melt by the Czochralski method (CZ method). This is called a Lalsky furnace (CZ furnace).
The CZ furnace 1 includes a quartz crucible 11 that is disposed in the center of the chamber 2 and contains a silicon melt 4 for growing a large-diameter silicon single crystal 3 having a diameter of 450 mm or larger, and the crucible 11. A crucible 12 made of graphite for holding 11, a heater (heating means: not shown) that is disposed outside the crucibles 11 and 12 and heats the silicon melt 4 in the crucible 11, and a silicon seed crystal (not shown) A pulling mechanism (lifting means) 16 having a pulling shaft 15 for pulling up the large-diameter silicon single crystal 2 from the seed chuck 14 and the silicon melt 4 to be attached, and a support shaft 17 called a pedestal for rotating and raising and lowering the crucibles 11 and 12. The large-diameter silicon single crystal 2 and the crucibles 11 and 12 are surrounded by a hot zone that is a cooling region after the growth of the large-diameter silicon single crystal 3. It is constituted by a heat insulating member 18 which is urchin disposed.

  The heat insulator 18 surrounds a substantially cylindrical heat insulating member 21 provided so as to surround the large-diameter silicon single crystal 3 at a position above the silicon melt 4 in the crucible 11, and an axial center portion of the crucible 11. The thick annular heat insulating member 22 provided on the outer side, the cylindrical heat insulating member 23 provided on the heat insulating member 22 and surrounding the upper part of the crucible 11, and the lower side of the heat insulating member 22 The cylindrical heat insulating member 24 and the thick disc-shaped heat insulating member 25 are provided.

In this heat insulation body 18, it is possible to change each shape, ie, an outer diameter, an internal diameter, thickness, etc. of the heat insulation members 21-25.
Shapes that can change the outer diameter, inner diameter, thickness, etc. of each of the heat insulating members 21 to 25 are block-shaped parts (heat-insulating pieces) finely divided in the height direction and the horizontal direction, and cylinders concentrically divided. Although there are parts (heat insulation pieces), block-shaped parts are preferable in order to finely control the thermal history when pulling up the large-diameter silicon single crystal 3.

FIG. 2 is a perspective view showing the block-shaped part 31 of the heat insulating member 22, and the heat insulating member 22 can be configured by stacking these block-shaped parts 31 vertically and horizontally. The same applies to the heat insulating members 21, 23-25.
FIG. 3 is a perspective view showing the cylindrical part 32 of the heat insulating member 22. The heat insulating member 22 can be configured by concentrically arranging a plurality of cylindrical parts 32 having different inner diameters. The same applies to the heat insulating members 21, 23-25.

  In pulling up the large-diameter silicon single crystal 3, in the cooling region above the solid-liquid interface of the large-diameter silicon single crystal 3, that is, in the hot zone, the heat insulating members 21 to 25 constituting the heat insulator 18 affect the thermal history. By changing the shape of the heat insulating members 21 to 25, the heat insulating characteristics of the heat insulating body 18 in the hot zone can be changed. As a result, the temperature gradient in the axial direction of the large-diameter silicon single crystal 3 can be changed. it can. Therefore, the thermal history of the large-diameter silicon single crystal 3 at the time of pulling up can be controlled by changing the shapes of the heat insulating members 21 to 25.

Indexes for evaluating the quality of the large-diameter silicon single crystal 3 include Gc and Gc / Ge which are crystal temperature gradients, and the crucible upper end temperature at which the crucible 11 may be deformed when the temperature becomes high during pulling. is there.
Therefore, by changing the shapes of the heat insulating members 21 to 25 that are considered to affect each of these indexes, the indexes can be optimized when the large-diameter silicon single crystal 3 is pulled up. Thereby, the quality of the large-diameter silicon single crystal 3 can be adjusted according to the target.

In this way, by selecting necessary parts from the block-shaped part 31 and the cylindrical part 32 and combining these parts to produce the heat insulating members 21 to 25, the heat at the time of pulling the large-diameter silicon single crystal 3 is increased. It is possible to make the history coincide with the thermal history at the time of pulling a small-diameter silicon single crystal having a diameter smaller than that of the large-diameter silicon single crystal, for example, 300 mm or 200 mm.
Thus, the thermal history of the large-diameter silicon single crystal 3 can be changed by changing the shape of each of the heat insulating members 21 to 25, that is, the outer diameter, the inner diameter, the thickness, and the like.

Here, the crystal defects of the silicon single crystal will be described.
As a crystal defect of a silicon single crystal, a Grown-in defect generated during the cooling process can be cited. As this Grown-in defect, a COP (Crystal Originated Particle) defect (vacancy) generated at 1100 ° C. to 1050 ° C. can be mentioned. Mold defects), OSF (Oxidation induced Stacking Fault) defects generated at 1050 ° C. to 900 ° C., and BMD (Bulk Micro Defect) defects generated at 900 ° C. to 600 ° C ..
Among these, COP defects that have a great influence on the initial oxide film breakdown voltage characteristic (GOP) of a silicon wafer in the semiconductor device manufacturing process are important.

4 is a partial longitudinal sectional view showing a defect distribution of a silicon single crystal grown while gradually decreasing the pulling rate, and FIG. 5 is a transverse sectional view taken along line AA in FIG.
Generally, various types of grown-in defects that cause problems in a semiconductor device manufacturing process occur in a silicon single crystal.
Typical Grown-in defects are a dislocation cluster generated in a dislocation cluster generation region which is an interstitial silicon dominant region and a COP defect or void generated in an infrared scatterer defect generation region which is a vacancy dominant region. There is a ring-shaped OSF generation region between these regions.

That is, a ring-shaped OSF generation region is located at the radial position of the silicon single crystal, and a defect-free region and an infrared scatterer defect generation region for generating COP or void are sequentially formed inside the ring-shaped OSF generation region. Is formed.
On the other hand, an oxygen precipitation promotion region, an oxygen precipitation suppression region (Pi region), and a dislocation cluster generation region are sequentially formed outside the ring-shaped OSF generation region. This oxygen precipitation promoting region is a vacancy type Grown-in defect free region (PV region), and the oxygen precipitation suppression region is an interstitial silicon type Grown-in defect free region (PI region).

Such a defect distribution is controlled by the following two factors. That is, one is the crystal pulling rate, and the other is the temperature distribution in the crystal immediately after solidification.
For example, at the stage where the pulling speed is high, the ring-shaped OSF generation region is located at the crystal outer periphery. Therefore, COP defects are generated in the entire area of the silicon single crystal in the radial direction of the silicon wafer obtained from the silicon single crystal grown under the high-speed pulling condition. Therefore, when the crystal pulling rate is gradually decreased, the ring-shaped OSF generation region gradually moves toward the center of the silicon single crystal as the pulling rate decreases, and finally the center of the silicon single crystal is obtained. It disappears in the department. As a result, in the silicon wafer obtained from the silicon single crystal grown under the low speed pulling condition, the whole area of the silicon single crystal in the radial direction becomes a dislocation cluster generation region.

In the CZ furnace 1 of the present embodiment, the temperature of the silicon melt 4 in the crucible 11 and the large-diameter silicon single crystal 3 are changed by changing the shape of each of the heat insulating members 21 to 25, that is, the outer diameter, inner diameter, thickness, and the like. The temperature distribution can be controlled, and the thermal history when pulling up the large-diameter silicon single crystal 3 can be easily controlled.
For example, the thermal history at the time of pulling up the large-diameter silicon single crystal 3 is changed to a thermal history at the time of pulling up the small-diameter silicon single crystal having a diameter smaller than that of the large-diameter silicon single crystal, for example, 300 mm or 200 mm. By matching, the large-diameter silicon single crystal 3 can be manufactured with the same quality as the small-diameter silicon single crystal having a smaller diameter, and at a low cost and in a short time.

Next, a method for manufacturing the large-diameter silicon single crystal of this embodiment using the CZ furnace 1 will be described.
First, the thermal history when pulling up the large-diameter silicon single crystal is simulated by the thermal history when pulling up the small-diameter silicon single crystal.
Here, the thermal history of the large-diameter silicon single crystal 3 is raised by changing the shape of each of the heat insulating members 21 to 25, that is, the outer diameter, inner diameter, thickness, etc., by pulling the small-diameter silicon single crystal having a diameter of 300 mm or 200 mm. Match the heat history of the hour.

The quality in the silicon single crystal is almost determined by the shape of the hot zone. Therefore, for example, when pulling up a plurality of types of large-diameter silicon single crystals 3 having a diameter of 450 mm with different crystal defect qualities, it is necessary to select the type of hot zone according to the type of large-diameter silicon single crystal 3 to be pulled up, A plurality of types of heat insulating members 21 to 25 constituting the hot zone are required.
The large-diameter silicon single crystal 3 is larger in size than the small-diameter silicon single crystal having a diameter of 200 mm or 300 mm, and the heat insulating member constituting the hot zone is also enlarged.

  In the present embodiment, each shape of the heat insulating members 21 to 25 can be configured by combining a plurality of block-shaped parts 31 and a plurality of cylindrical parts 32, so that various types of hot zones can be handled. It is not necessary to prepare the heat insulating members 21 to 25 for each type. Therefore, an optimal hot zone configuration can be obtained in a short time and at a low cost in accordance with the type of large-diameter silicon single crystal 3 to be pulled.

In this way, by selecting necessary parts from the block-shaped part 31 and the cylindrical part 32 and combining these parts to produce the heat insulating members 21 to 25, the heat at the time of pulling the large-diameter silicon single crystal 3 is increased. It is possible to make the history coincide with the thermal history at the time of pulling a small-diameter silicon single crystal having a diameter smaller than that of the large-diameter silicon single crystal, for example, 300 mm or 200 mm.
Therefore, it is possible to change the thermal history of the large-diameter silicon single crystal 3 by changing the shape of each of the heat insulating members 21 to 25, that is, the outer diameter, the inner diameter, the thickness, and the like.
Table 1 shows an example of the variable range of dimensions and the evaluation index value of the heat insulating member in the hot zone for pulling up the large-diameter silicon single crystal 3 having a desired quality.

  FIG. 6 is a diagram showing the results of simulation of thermal history during pulling of a silicon single crystal. In the figure, A represents the distance (mm) from the solid-liquid interface and the crystal temperature (° C.) in a 450 mm diameter silicon single crystal. B is the relationship between the distance (mm) from the solid-liquid interface in the 300 mm diameter silicon single crystal and the crystal temperature (° C.), and C is the distance from the solid-liquid interface (mm) in the 200 mm diameter silicon single crystal. ) And the crystal temperature (° C.).

According to FIG. 6, it can be seen that the cooling rate of the silicon single crystal differs greatly between the 450 mm diameter silicon single crystal and the 300 mm or 200 mm diameter silicon single crystal.
In a silicon single crystal, a temperature region where a grown-in defect is formed is determined. For example, a temperature region where a COP defect is formed is 1100 ° C. to 1050 ° C., and a temperature region where an OSF defect is formed is 1050 ° C. to 900 ° C. The temperature region where the BMD defect is formed is 900 ° C. to 600 ° C. Therefore, by controlling the residence time in these temperature regions, one or more of COP defects, OSF defects, and BMD defects can be formed at a desired concentration in the silicon single crystal.

As described above, the large-diameter silicon single crystal and the small-diameter silicon single crystal have different amounts of heat, so that the cooling rate is greatly different, and thus the thermal history is greatly different.
Therefore, a simulation is performed on Gc and Gc / Ge which are crystal temperature gradients when pulling up the silicon single crystal, the crucible upper end temperature when pulling up, and the heater power, and the above index is affected based on the experimental results. If the shape of the heat insulating members 21 to 25 considered to be determined is determined, the hot zone can be optimized according to the shape of the silicon single crystal to be pulled up.

For example, when pulling up a large-diameter silicon single crystal, since the pulling is performed by slow cooling, the shape of the heat insulating members 21 to 25 considered to affect the above index is changed based on the experimental results of the above simulation. By doing so, the cooling rate of the single crystal can be promoted. Furthermore, the cooling rate of the single crystal can also be accelerated by increasing the pulling rate of the single crystal. Therefore, by combining both of these, it is possible to arbitrarily control the cooling rate of the single crystal.
As described above, the hot history when pulling up the large-diameter silicon single crystal 3 is optimized by simulating the thermal history when pulling up the large-diameter silicon single crystal with the thermal history when pulling up the small-diameter silicon single crystal. Can do. Therefore, this optimized hot zone makes it possible to grow a large-diameter silicon single crystal 3 excellent in crystal defect quality.

  FIG. 7 is a diagram showing the thermal history after solidification at the time of pulling the silicon single crystal, that is, the result of simulating the relationship between the cooling time (minutes) and the crystal temperature (° C.), and FIG. 8 shows each thermal history of FIG. It is a figure which shows the magnitude | size of the corresponding COP defect, In the figure, D is the relationship between the cooling time (minutes) after solidification and the crystal temperature (degreeC) in a 450 mm diameter silicon single crystal, E is 450 mm diameter silicon. The relationship between the cooling time (min) after solidification of a thermal history different from D in a single crystal and the crystal temperature (° C.), F is the cooling time (min) after solidification and crystal temperature (° C.) of a 300 mm diameter silicon single crystal. G represents the relationship between the cooling time (minutes) after solidification of the heat history different from F in the 300 mm diameter silicon single crystal and the crystal temperature (° C.), and H represents the solidification in the 200 mm diameter silicon single crystal. After cooling time (minutes) and The relationship between the temperature (° C.), J is the relationship between the cooling time after solidification thermal history different from D and E in the silicon single crystal 450mm diameter and (min) and crystallization temperature (° C.), are shown respectively.

  In J above, the necessary parts are selected from the block-shaped part 31 and the cylindrical part 32, and these parts are combined to produce each of the heat insulating members 21 to 25, whereby the large-diameter silicon single crystal 3 is pulled up. By simulating the thermal history at the time of pulling up the small-diameter silicon single crystal, the cooling rate of the single crystal is promoted and the pulling rate of the single crystal is set to 0.65 mm / min or more. Thus, the residence time in the crystal defect formation temperature region (1100 ° C. to 1050 ° C.) in which COP defects are formed in the silicon single crystal is set to 30 minutes or less.

7 and 8, since the thermal history of the silicon single crystal varies depending on the pulling condition of the single crystal and the hot zone shape, the temperature gradient of the single crystal and the residence time during which the single crystal stays in the crystal defect formation temperature region also differ. Yes.
According to FIGS. 7 and 8, the crystal defect formation temperature region in which COP defects are formed in the silicon single crystal is 1100 ° C. to 1050 ° C. Therefore, the longer the residence time of this crystal defect formation temperature region is, It can be seen that COP defects are increased.
Further, it can be seen that when the stay time exceeds a certain time, the growth of the COP defect is saturated and the size of the COP defect becomes constant.

  As described above, when pulling up a 450 mm diameter silicon single crystal, the necessary parts are selected from the block-shaped part 31 and the cylindrical part 32, and these parts are combined to produce each of the heat insulating members 21 to 25. If the thermal history is such that the residence time in the crystal defect formation temperature region (1100 ° C. to 1050 ° C.) where COP defects are formed in the single crystal is 30 minutes or less, the COP defects formed in the silicon single crystal are reduced. be able to. As a result, by simulating the thermal history of a silicon single crystal with a diameter of 450 mm using a silicon single crystal with a diameter of 200 mm or 300 mm, a crystal defect of the silicon single crystal with a diameter of 450 mm, for example, a grown-in defect such as a COP defect And the quality of a 450 mm diameter silicon single crystal can be improved.

According to the method for manufacturing a large-diameter silicon single crystal of the present embodiment, a hot zone is selected from necessary parts from the block-shaped part 31 and the cylindrical part 32, and each of the heat insulating members 21 to 25 in which these parts are combined. By using it, the thermal history at the time of pulling up the large-diameter silicon single crystal 3 can be easily controlled.
Therefore, a large-diameter silicon single crystal having a diameter of 450 mm or larger can be manufactured with the same quality as a small-diameter silicon single crystal having a smaller diameter, and at a low cost and in a short time.

According to the large-diameter silicon single crystal manufacturing apparatus of the present embodiment, the heat insulator 18 is selected from the block-shaped part 31 and the cylindrical part 32, and necessary parts are combined by the heat insulating members 21 to 25 combining these parts. Since it comprised, the heat insulation members 21-25 can be produced only by the combination of the parts 31 and 32, Therefore, the hot zone at the time of pulling up the large diameter silicon single crystal 3 can be produced easily and in a short time. The thermal history during pulling of the large-diameter silicon single crystal 3 can be easily controlled.
Therefore, the large-diameter silicon single crystal 3 having a diameter of 450 mm or larger can be manufactured with the same quality as the small-diameter silicon single crystal having a smaller diameter, and at a low cost and in a short time.

DESCRIPTION OF SYMBOLS 1 CZ furnace 2 Chamber 3 Large diameter silicon single crystal 4 Silicon melt 11 Crucible 12 Crucible 13 Heater 14 Seed chuck 15 Lifting shaft 16 Lifting mechanism 17 Support shaft 18 Heat insulator 21-25 Thermal insulation member 31 Block-shaped part 32 Cylindrical part

Claims (1)

A method for producing a large-diameter silicon single crystal in which a large-diameter silicon single crystal is grown from a silicon melt contained in a crucible by the Czochralski method,
Wherein is arranged to surround the large diameter silicon single crystal and the crucible Rutotomoni, outer diameter in combination isosamples select one or more thermal insulation pieces from multiple species inner diameter, a plurality of changeable thickness In an apparatus having a heat insulating member , the hot zone is composed of the plurality of heat insulating members, and by optimizing the shape of the hot zone that forms the cooling region above the solid-liquid interface of the large-diameter silicon single crystal,
The thermal history at the time of pulling up the large-diameter silicon single crystal is a crystal defect formation temperature region when cooling the grown small-diameter silicon single crystal having a smaller diameter than the large-diameter silicon single crystal, and the crystal defect formation temperature region. A method for producing a large-diameter silicon single crystal characterized by simulating a thermal history during pulling of a small-diameter silicon single crystal including a residence time and growing the large-diameter silicon single crystal based on the simulated thermal history.

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