JP2001342097A - Silicon monocrystal pulling device and pulling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CZ method of silicon monocrystal pulling method and a device for the same which can improve an acquisition rate of non defective crystal (perfect crystal) and its sureness. SOLUTION: The silicon monocrystal pulling device is pulling a crystal from a silicon molten liquid surrounding the crystal with a heat shielding body. At the time of pulling the monocrystal from the silicon molten liquid, parameters are set to form a non defective region in the crystal, among them at least a distance from a bottom of the heat shielding body to the level of molten liquid and the pulling speed of the silicon monocrystal is set so as to be kept in an allowable width. Thereby, the sureness for forming the non defective crystal region can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a Czochralski method (C) for pulling a silicon single crystal from a silicon melt.
Z method) Silicon single crystal pulling apparatus and method, especially Gro
A CZ capable of easily and reproducibly forming defect-free crystals (complete crystals) containing no wn-in defects in a silicon ingot and realizing acquisition of more defect-free crystal wafers from the silicon ingot. The present invention relates to an apparatus and a method for pulling a silicon single crystal.

[0002]

2. Description of the Related Art Along with the recent improvement in device characteristics associated with high integration and miniaturization of semiconductor circuits, a demand for reduction of crystal defects generated in a process of manufacturing a silicon single crystal has been increasing. In order to respond to this, when manufacturing a silicon single crystal by the CZ method, it is necessary to pull up the silicon single crystal by precisely controlling the defect distribution in the wafer surface.

Here, when pulling a silicon single crystal by the CZ method, the crystal defect distribution generally has a correlation with the pulling speed V and V / G expressed by using an axial temperature gradient G near the melt. It is reported that there is. In particular, in order to grow a crystal free of crystal defects such as void defects, dislocation clusters, and OSF rings, which are called defect-free crystals (perfect crystals) (however, recently, there are also those having an OSF ring. ), It is necessary to control V / G with high accuracy.

For example, Japanese Patent Application Laid-Open No. Hei 8-330316 discloses that as a condition for forming a defect-free region of a defect-free crystal (perfect crystal), the crystal pulling speed is set to V (mm / min), and the melting point of silicon is determined. Assuming that the average of the temperature gradient in the crystal in the axial direction between 1300 ° C. is G (° C./mm), the ratio represented by V / G is 0.20 to 0.22 mm ² / ° C. min. It is described that the crystal is pulled under control.

In addition, in order to control the defect distribution in the wafer surface determined by V / G, the axial temperature gradient at the center of the crystal during crystal growth is defined as Gc, and the axial temperature gradient at the outer periphery of the crystal is determined. When the gradient is Ge, the crystal growth rate V is set at ±
Control of ΔG = Ge−Gc within 1 ° C./mm within 0.02 mm (JP-A-11-199386);
= Gc ± 0.3 ° C. (JP-A-11-199)
383) has been proposed.

[0006]

However, in practice, a very narrow range (for example, disclosed in Japanese Unexamined Patent Publication No.
It is extremely difficult to control V / G with high accuracy by the method described in US Pat.

[0007] The reason for this is that, first, actually, the inner diameter of the quartz crucible fluctuates or the quartz crucible is depressed or deformed due to the radiant heat from the heater. Are not always the same.

[0008] In addition, a C in which a heat shield is installed in the furnace.
When the Z method silicon single crystal pulling apparatus is used, the heat shield expands and contracts when pulling the silicon single crystal. As a result, the axial temperature gradient G near the interface during crystal growth
The temperature distribution in the radial direction changes, and the V / G in the radial direction changes. Therefore, even if only the pulling speed is controlled with high accuracy, it is very possible to obtain the same defect distribution with good reproducibility. It was difficult.

Further, even when the axial temperature gradient G is controlled, G actually changes every moment during the crystal growth, and the radial distribution of the axial temperature gradient during the crystal growth is changed. Since it is very difficult to grasp accurately, it was not possible to obtain a desired defect distribution within the wafer surface with good reproducibility.

This will be described in more detail. For example, according to Japanese Patent Application Laid-Open No. 8-330316, if G is uniform in the radial direction, for example, when G = 3.0 ° C./mm, the pulling speed V becomes It should be controlled to 0.63 ± 0.03 mm / min, but G is not uniform in the radial direction, and when the change in G in the radial direction reaches 10%, the allowable width becomes zero. As a result, it becomes impossible to produce defect-free crystals (perfect crystals). This means that a slight decrease in the uniformity of G in the radial direction makes it virtually impossible to produce a defect-free crystal (perfect crystal), but the change in G in the radial direction is reduced to 10%. This can sufficiently occur, and the method proposed in Japanese Patent Application Laid-Open No. 8-330316 inevitably makes the production of defect-free crystals extremely unstable.

The present invention has been made in view of the above problems, and has as its object to provide a defect-free crystal (perfect crystal).
An object of the present invention is to provide a CZ method silicon single crystal pulling apparatus and a method capable of improving the acquisition rate and reliability of the method.

[0012]

Means for Solving the Problems In order to solve the above problems, the inventors of the present invention have conducted intensive studies, and as a result, in a CZ method silicon single crystal pulling apparatus having a heat shield in a furnace, When growing a defect-free crystal under the same conditions, the change in the distance from the bottom surface of the heat shield to the melt surface (hereinafter, simply referred to as “GAP”) is caused by the temperature gradient near the interface during the crystal growth. It is understood that it has greatly affected G,
It has been found that this causes the variation in the defect distribution in the radial direction on the wafer surface.

Further, the present inventors can suppress the change in the distribution of defects in the wafer surface due to the axial temperature gradient G by minimizing the amount of change in the GAP, whereby the wafer for each pulled crystal can be suppressed. They have found that the reproducibility of the defect distribution in the plane can be improved, and have completed the present invention.

From the above, in the present invention,
The following method is provided as a basic principle.

(1) A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. In the case of performing, the amount of change in the distance from the bottom surface of the heat shield to the melt surface is tracked, and by suppressing the amount of change to a minimum, the crystal in the plane of the silicon wafer cut out from the silicon single crystal A method to increase the reproducibility of defect distribution.

Here, the method according to the above (1) is concerned with the reproducibility of the crystal defect distribution in the plane of the silicon wafer, especially in the radial direction, and does not consider the magnitude of the crystal defect density. If the reproducibility of the zero case is ensured, it means that the accuracy of the production of defect-free crystals has been increased.

Thus, according to the present invention, a method for producing a defect-free crystal with a certain degree of certainty is also provided. The method generally described is (2) below. Further, in view of the basic principle of the present invention, in the step of pulling a defect-free crystal, the manufacturing accuracy of the defect-free crystal is increased by giving a certain degree of freedom to increase or decrease in the pulling speed of a silicon single crystal. The following (3) generally describes the present invention.

The term “crystal defect” used herein refers to a void defect, a dislocation cluster, or a grown crystal such as an OSF ring.
-In means defect. As for “within a predetermined allowable range” of the following (2), specific numerical values under specific conditions are specified in the examples, but are not limited to the numerical values indicated therein. An appropriate value is set according to the situation (this “appropriate value” can be derived by a person skilled in the art by performing an experiment similar to the experiment shown in the examples).

(2) A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When performing, for parameters set when forming a defect-free crystal region in the silicon single crystal being pulled from the silicon melt, at least the distance from the bottom of the heat shield to the melt surface and A method of increasing the accuracy of forming a defect-free crystal region by pulling the silicon single crystal while setting the pulling speed of the silicon single crystal so as to fall within a predetermined allowable width.

(3) A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When forming a defect-free crystal region in a silicon single crystal being pulled from a silicon melt, the precision of controlling the distance from the bottom surface of the heat shield to the melt surface is increased. To increase the allowable range of increase or decrease in the pulling speed of the silicon single crystal.

A CZ method silicon single crystal pulling apparatus suitable for carrying out the method according to the present invention as described above is as follows.

(4) A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the silicon single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. For parameters set when forming a defect-free crystal region in a silicon single crystal being pulled from a liquid, at least a distance from the bottom surface of the heat shield to the melt surface and a pulling speed of the silicon single crystal A silicon single crystal pulling apparatus characterized in that the silicon single crystal is pulled while setting to fall within a predetermined allowable width.

(5) A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the silicon single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When forming a defect-free crystal region in a silicon single crystal being pulled from the liquid, the pulling speed of the silicon single crystal is controlled by precisely controlling the distance from the bottom surface of the heat shield to the melt surface. A silicon single crystal pulling apparatus characterized in that the silicon single crystal can be pulled with a certain margin.

(6) A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, the apparatus comprising a heat shield surrounding a periphery of the silicon single crystal. Measure and track the distance from the bottom surface of the heat shield to the melt surface,
A silicon single crystal pulling apparatus characterized in that a silicon ingot containing a large number of defect-free crystal regions is manufactured by pulling a silicon single crystal while precisely controlling the distance as calculated.

(7) A magnetic field applying means for applying a magnetic field to the silicon melt is provided (4).
To (6) the silicon single crystal pulling apparatus according to any one of (1) to (6).

It is preferable to apply a horizontal magnetic field of at least 2500 G or more. The magnetic field is 2000
Below G, the uniformity of G in the wafer surface becomes insufficient and 5
Since it is considered that the defect-free rate deteriorates at 000 G or more, it is preferable to adjust the ratio in the range of 2500 G to 5000 G.

By the way, since the silicon ingot manufactured by these apparatuses contains more defect-free regions than the conventional one and the accuracy of forming the defect-free region is higher, a large number of silicon ingots are continuously pulled up. Even in the case of a defective product, there is almost no possibility that defective products (silicon ingots containing almost no defect-free region) are mixed. Therefore, in the present invention, a silicon ingot group that is continuously pulled up and manufactured as described below is also included in the scope.

(8) A silicon ingot group including a large number of defect-free regions manufactured by the silicon single crystal pulling apparatus according to any one of (4) to (7).

Further, in the present invention, as a more specific embodiment, the following method is also included.

(9) Increase the set GAP by 0.2-
A method for growing a single crystal, characterized in that the pulling is performed by controlling the GAP to within a set value ± 2.0 mm by 0.5 times.

(10) Using a melt level detector, precisely measure the distance from the bottom surface of the heat shield to the surface of the melt,
The difference between the actually measured GAP value and the set GAP is fed back to the crucible feed amount to adjust the crucible feed, thereby achieving G
How to precisely control the AP.

(11) A method for growing a defect-free crystal (perfect crystal), characterized by widening the allowable range of the pulling rate by applying a magnetic field.

[Definition of Terms and the Like] In this specification, the term "ingot" means a single crystal grown from a silicon melt, and a "wafer" is cut out from the ingot.

A defect-free crystal (perfect crystal) means a void (cavity) defect, an oxidation-induced stacking fault (OSF).
Induced Stacking Fault) and a crystal in which neither dislocation cluster exists. In addition, a defect-free region (perfectly crystalline region) or a defect-free region is defined as
Among crystals, void (cavity) defects, oxidation-induced stacking faults
(OSF; Oxidation Induced Stacking Fault) and an area where neither dislocation cluster exists.

The "heat shield" is installed in the furnace to shield radiant heat from the surface of the raw material melt and heat radiation from the heater in the furnace. It also works to rectify the flow of water. Here, even if gas rectification is the main purpose, as long as the heat from the melt surface or the heater is shielded in some way,
Since it is sufficient to function as the heat shield according to the present invention, the heat shield is included in the concept of “heat shield” in the present invention, as long as the heat shield is performed in any form.

The "magnetic field applying means for applying a magnetic field to the silicon melt" is described in, for example, JP-A-56-45889.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, it is possible to use those disclosed in Japanese Patent Application Laid-Open Publication No. H11-260, 1988. Among the magnetic field applying means, a cusp magnetic field generating means such as disclosed in Japanese Patent Application Laid-Open No. 58-217493 can be used.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a basic configuration of a hot zone of a CZ method single crystal pulling apparatus for carrying out the present invention. As shown in FIG. 1, a CZ method silicon single crystal pulling apparatus for carrying out the present invention comprises a crucible 21 which stores a silicon melt 13 and rotates by itself, and a heater 22 which heats the crucible 21.
A heat shield 23 that surrounds the single crystal 11 pulled up while being rotated from the silicon melt 13 and adjusts the amount of radiant heat to the single crystal 11, and a solenoid 27 for applying a magnetic field to the silicon melt 13. ,including.

Here, the heat shield 23 is generally made of a carbon material, and adjusts the temperature of the side surface of the single crystal 11 by shielding radiant heat from the silicon melt 13 or the like. In addition, as shown in FIG.
Preferably, a side heater 22a and a bottom heater 22b
It is composed of

In practicing the present invention, it is necessary to precisely track and control the distance L from the heat shield bottom surface 23a to the melt surface 13a. It is preferable to use the melt level detecting device according to Japanese Patent Application No. 2000-083030. In practicing the present invention, Japanese Patent Application
In the case where the distance L measured by the melt level detecting device according to No. 083030 deviates from a preset range, for example, the crucible 21 is moved up and down to adjust the crucible 21 to an appropriate value.

Here, FIG. 2 and FIG.
It is a block diagram showing an embodiment of a melt level detecting device concerning -083030. The CZ method single crystal pulling apparatus equipped with this melt level detecting device employs a distance measuring unit 8 based on the principle of triangulation. The distance measuring unit 8 applies a laser beam to the silicon melt surface 13a. A laser light irradiator for projecting and a light receiver for receiving the laser light reflected from the silicon melt liquid surface 13a are provided.

The laser beam 2 output from the distance measuring unit 8 is reflected by the scan mirror 28,
The light passes through the entrance window 18 and is projected onto the silicon melt surface 13a via the quartz prism 20 installed in the chamber 17 of the pulling device. The laser beam 2 projected on the silicon melt liquid surface 13a is once specularly reflected here,
The measurement spot 31 strikes the lower surface (bottom surface) 23a of the lower end portion of the heat shield 23. Then, the laser light 2 irradiated as the measurement spot 31 on the bottom surface 23a of the heat shield 23 is scattered here, and a part of the reflected scattered light is specularly reflected on the silicon melt surface 13a (secondary reflected light). ), The light enters the distance measurement unit 8 via the prism 20, the entrance window 18, and the scan mirror 28. The distance measurement unit 8 based on the principle of triangulation calculates the distance (Dw) at that time from the distance between the laser light irradiator and the light receiver built therein, the irradiation angle and the light reception angle of the laser light. I do.

Next, by rotating or moving the scan mirror 28, the measurement spot 31 is moved to the heat shield 23.
Is moved to the upper surface 25 at the lower end of the lens, and the reflected light (primary reflected light) therefrom is received by the distance measurement unit 8 via the prism 20, the entrance window 18, and the scan mirror 28 (in FIG. Route shown). Then, the distance to the upper surface of the lower end of the heat shield 23 is calculated by the same method as when Dw is calculated, and the thickness 2 of the lower end of the heat shield 23 is calculated.
By adding 6, the distance (Ds) to the back surface (bottom surface) 23a of the lower end portion of the heat shield 23 is obtained.

The distance (GA) from the bottom surface 23a of the heat shield to the surface 13a of the silicon melt is calculated by the following equation (1).
Calculate distance L of P) L.

GAP distance L = (Dw−Ds) / 2 (1)

[0045]

Embodiment [Setting conditions] A case where a single crystal is pulled by using a CZ method silicon single crystal pulling apparatus as shown in FIG. 1 and precisely controlling the crystal pulling speed V and the distance L of the GAP. The degree of formation of defect-free crystals was examined in comparison with the case where no such process was performed. The experiment was diameter 20
This was performed using a 0 mm crystal.

The distribution of crystal defects can be generally investigated by observing the surface of a crystal after immersing it in an etching solution. In this embodiment, voids and dislocation clusters are not stirred by Secco etching. Then, the OSF was subjected to oxidative heat treatment at 780 ° C. for 3 hours and then at 1000 ° C. for 16 hours, followed by light etching to investigate the distribution of defects.

The distance L of the gap was adjusted to be around 60 mm, and the crystal pulling speed V was 0.4 mm / m in a steady state.
It was adjusted to be about in. The magnetic field is 300
A horizontal magnetic field of 0 G was applied.

[Measurement of GAP distance L] GAP distance L
Is measured by the melt level detector according to Japanese Patent Application No. 2000-083030, the measured value is fed back to the crucible feed amount, and the GAP distance L is set to ±
At the same time, the crystal pulling speed V is controlled to be within a set value ± 0.01 mm / min.
It controlled so that it might be within.

[Dispersion of distance L of GAP when using a general CZ method silicon single crystal pulling apparatus]
Using a CZ method silicon single crystal pulling apparatus as shown in FIG.
The silicon single crystal was pulled up a plurality of times while controlling the distance L of P to be constant. FIG. 4 shows the measured values of the distance L of the GAP in such a case.

As shown in FIG. 4, in the case where the control is performed by the conventional method, even if the control is performed so that the distance L of the GAP is constant, a considerable variation actually occurs. I understand. This is considered to be caused by the variation in the inner diameter of the quartz crucible, the set or deformation of quartz during the growth of silicon single crystal, and the expansion and contraction of the heat shield, as described above.

[Control of Crystal Pulling Speed V, Control of GAP Distance L] <Control of Crystal Pulling Speed V Only (Conventional Method)> First, the distance L of the GAP is set to be constant according to a conventional method. Then, an attempt was made to produce a defect-free crystal by adjusting the crystal pulling speed V.

Then, as shown in FIG. 5, the crystal pulling speed V was settled with a slight deviation from the set value by the precise adjustment, but the distance L of the GAP was reduced as described in Japanese Patent Application No. When measured by the melt level detecting device according to No. 083030, it was found that the measured value (GAP actual value = distance L of GAP) greatly deviated from the set value. This deviation reached 4 mm to 8 mm in the last stage of crystal pulling.

Then, as shown in the defect distribution diagram below the graph, as the actual gap value deviated from the set gap value, the defect-free region disappeared, and dislocation clusters appeared.

As shown in FIG. 5, in the conventional method, the entire product target area could not be made a defect-free area because the actual gap value actually deviated from the set gap value. Can be inferred to be the reason.

<Precision control of only GAP distance L (control experiment)>
The feedback control was precisely performed based on the actually measured value from the melt level detection device according to No.-083030, while the crystal pulling speed V was intentionally shifted from the set value.

Then, as shown in FIG. 6, the defect-free region disappeared at a portion where the crystal pulling speed V largely deviated from the V setting value, and dislocation clusters and OSF rings appeared.

From this, regarding the distance L of the GAP,
It can be seen that even when the silicon single crystal is pulled under precise control based on the actual measurement value, the defect-free region disappears at a place where the crystal pulling speed V largely deviates from the set value, but at the same time, It can be seen that there is a certain allowable width, and if the crystal pulling speed V changes within a range not exceeding the allowable width, a defect-free region is formed.

<Precision Control of Crystal Pulling Speed V Only (Control Experiment)> Next, while precisely controlling the crystal pulling speed V, the distance L of the GAP was intentionally shifted from the set value.

Then, as shown in FIG. 7, the defect-free region disappeared at a place where the distance L of the GAP greatly deviated from the set value of the GAP, and dislocation clusters and OSF rings appeared.

From this, the GAP distance L also has an allowable range for the case where the crystal pulling speed V is precisely controlled, and when the GAP distance L changes within a range not exceeding the allowable range, It can be seen that a defect-free region is formed.

<Precision Control of GAP Distance L and Crystal Pulling Speed V (Invention)> Finally, the GAP distance L is determined based on the actually measured value from the melt level detecting device according to Japanese Patent Application No. 2000-083030. In addition to precise feedback control, the crystal pulling speed V was also precisely controlled.

As a result, as shown in FIG. 8, a defect-free crystal region was formed over a wide region of the manufactured silicon ingot. In this silicon ingot, most of the product target region is a defect-free crystal region, and the acquisition rate of defect-free crystal silicon wafers is remarkably good.

[Allowable Width] Here, when the "allowable width" suggested in the above experiment was precisely measured, the result shown in FIG. 9 was obtained.

As shown in FIG. 9, when GAP distance L is within the range of ± 2 mm, crystal pulling speed V has an allowable width of ± 0.01 mm / min. However, as shown in FIG. 9, when the distance L of the gap is shifted by 3 mm, the allowable range of the crystal pulling speed V is ±
It will be reduced to a half of 0.005 mm / min.

As described above, the more precisely the distance L of the gap is controlled, the larger the allowable range of the crystal pulling speed V becomes. In addition, in order to carry out the present invention, it is not necessary to apply a magnetic field. However, when the magnetic field is applied, the permissible range of the speed V becomes larger.
The optimal distance L of the GAP becomes smaller than when no magnetic field is applied).

[0066]

As can be seen from the above description, in pulling a silicon single crystal, the radial distribution of the axial temperature gradient G during crystal growth is increased by controlling the distance L of the GAP with high precision. It can be changed with good reproducibility in the longitudinal direction of the crystal. Here, it is very difficult to keep G constant in the longitudinal direction of the crystal.
By precisely controlling the distance L of P, it is also possible to precisely control the radial G, so that a defect-free crystal can be stably manufactured.

That is, according to the present invention, a defect-free crystal can be easily and reproducibly formed in a silicon ingot, and more defect-free crystal wafers can be obtained from the silicon ingot. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a hot zone of a CZ method silicon single crystal pulling apparatus for carrying out the present invention.

FIG. 2 is a Japanese Patent Application No. 2000 suitable for carrying out the present invention.
It is a block diagram showing an embodiment of a melt level detecting device concerning -083030.

FIG. 3 is a Japanese Patent Application No. 2000 suitable for carrying out the present invention.
It is a block diagram for explaining embodiment of a melt level detection apparatus concerning -083030.

FIG. 4 is a diagram for explaining the variation of the measured gap distance L of the gap, and the gap distance when the silicon single crystal is pulled up a plurality of times using a general CZ method silicon single crystal pulling apparatus. 5 is a graph showing measured values of L. In the figure, the vertical axis indicates the size of the distance L of the GAP, and the horizontal axis indicates the length of the silicon single crystal pulled from the silicon melt.

FIG. 5 is a diagram showing a result when an attempt is made to produce a defect-free crystal by adjusting a crystal pulling speed V by setting a distance L of a GAP constant and following a conventional method. In the figure, the upper figure is a graph showing the relationship between the length (horizontal axis) of the silicon single crystal pulled from the silicon melt, the crystal pulling speed V, and the distance L (vertical axis) of GAP, and the lower figure is The figure is a defect distribution diagram produced corresponding to the length of a silicon single crystal pulled from a silicon melt.

FIG. 6 As a control experiment, an attempt was made to produce a defect-free crystal in which the distance L of the GAP was precisely feedback-controlled based on the actually measured value, while the crystal pulling speed V was deliberately shifted from a set value. It is a figure showing a result at the time.
In the figure, the upper figure is a graph showing the relationship between the length (horizontal axis) of the silicon single crystal pulled from the silicon melt, the crystal pulling speed V, and the distance L (vertical axis) of the GAP,
The lower figure is a defect distribution diagram produced corresponding to the length of a silicon single crystal pulled from a silicon melt.

FIG. 7 is a diagram showing a result of an attempt to produce a defect-free crystal by intentionally shifting a GAP distance L from a set value while precisely controlling a crystal pulling speed V as a control experiment. . In the figure, the upper figure shows the length of the silicon single crystal pulled from the silicon melt (horizontal axis)
FIG. 4 is a graph showing the relationship between the crystal pulling speed V and the distance L (vertical axis) of the GAP, and the lower diagram shows a defect distribution diagram corresponding to the length of a silicon single crystal pulled from a silicon melt. It is.

FIG. 8 shows the distance L of the GAP to the above-mentioned Japanese Patent Application No. 2000-0.
FIG. 8 is a diagram showing the results when trying to produce a defect-free crystal by precisely performing feedback control based on an actual measurement value from the melt level detection device according to No. 83030 and also precisely controlling the crystal pulling speed V by shifting the control. In the figure, the upper figure is a graph showing the relationship between the length (horizontal axis) of the silicon single crystal pulled from the silicon melt, the crystal pulling speed V, and the distance L (vertical axis) of GAP, and the lower figure is The figure is a defect distribution diagram produced corresponding to the length of a silicon single crystal pulled from a silicon melt.

FIG. 9 is a diagram showing a result of precisely measuring an “allowable width” suggested in an experiment.

[Explanation of symbols]

 2 Laser beam 8 Distance measuring unit 11 Single crystal 13 Silicon melt 13a Melt surface 17 Chamber 18 Incident window 20 Quartz prism 21 Crucible 22 Heater 22a Side heater 22b Bottom heater 23 Heat shield 23a Heat shield bottom 25 Heat shield Upper surface of lower end of body 23 Thickness of lower end of heat shield 23 Solenoid 28 Scan mirror 31 Measurement spot L Distance from heat shield bottom surface 23a to melt surface 13a

Claims (11)

[Claims] A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When performing, by tracking the change in the distance from the bottom surface of the heat shield to the melt surface, by minimizing the change,
A method for improving the reproducibility of a crystal defect distribution in a plane of a silicon wafer cut from a silicon single crystal. 2. A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When performing, for the parameters set when forming a defect-free crystal region in the silicon single crystal being pulled from the silicon melt, at least the distance from the bottom surface of the heat shield to the melt surface and the A method of increasing the accuracy of forming a defect-free crystal region by setting a pulling speed of a silicon single crystal so as to fall within a predetermined allowable width and pulling the silicon single crystal. 3. A single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. When performing, when forming a defect-free crystal region in a silicon single crystal pulled up from a silicon melt, increasing the precision of control of the distance from the bottom surface of the heat shield to the melt surface. Method to increase the allowable range of increase / decrease of the pulling speed of the silicon single crystal. 4. A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, the apparatus comprising a heat shield surrounding a periphery of the silicon single crystal. About parameters set when forming a defect-free crystal region in a silicon single crystal being pulled from among at least the distance from the bottom surface of the heat shield to the melt surface and the pulling speed of the silicon single crystal Is a silicon single crystal pulling apparatus characterized in that the silicon single crystal is pulled while being set to fall within a predetermined allowable width. 5. A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, comprising: a silicon single crystal pulling apparatus including a heat shield surrounding a periphery of the silicon single crystal. When forming a defect-free crystal region in a silicon single crystal being pulled from within, by precisely controlling the distance from the bottom surface of the heat shield to the melt surface, the pulling speed of the silicon single crystal can be reduced. An apparatus for pulling a silicon single crystal, wherein the silicon single crystal can be pulled with a certain margin. 6. A silicon single crystal pulling apparatus for pulling a silicon single crystal from a silicon melt, wherein the silicon single crystal pulling apparatus includes a heat shield surrounding a periphery of the silicon single crystal. By actually measuring and tracking the distance from the bottom surface of the heat shield to the melt surface, and pulling up the silicon single crystal while controlling the distance precisely as calculated, a silicon ingot containing many defect-free crystal regions can be obtained. A silicon single crystal pulling apparatus characterized by being manufactured. 7. The silicon single crystal pulling apparatus according to claim 4, further comprising magnetic field applying means for applying a magnetic field to the silicon melt. 8. A silicon ingot group including a large number of defect-free regions, which is manufactured by the silicon single crystal pulling apparatus according to claim 4. 9. Set GAP is 0.2-0.5 of the pulling diameter
A method for growing a single crystal, wherein the pulling is performed while controlling the GAP within a set value ± 2.0 mm. 10. A crucible feed is adjusted by precisely measuring the distance from the bottom surface of the heat shield to the surface of the melt using a melt level detecting device, and feeding back the difference between the actually measured GAP value and the set GAP to the crucible feed amount. Method to control GAP precisely. 11. A method for growing a defect-free crystal, characterized by widening an allowable range of a pulling speed by applying a magnetic field.