JP2002255684A - Manufacturing method of silicone monocrystal ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of silicone monocrystal ingot which is excellent in productivity and manufactures silicone monocrystal ingot of large diameter and big weight with an easy method. SOLUTION: In this manufacturing method of silicone monocrystal ingot, a seed crystal S is brought into contact with melted polysilicone blank M and the silicone monocrystal ingot Ig is grown. Therein, the tensile strength of the specified part Igt is increased by making impurity concentration of the specified part Igt higher when a specified part Igt of silicone monocrystal ingot Ig to be grown is grown.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a silicon single crystal ingot, and more particularly, to increasing the impurity concentration of a specific portion of a silicon single crystal ingot to increase the strength of the specific portion, and utilizing this to improve productivity. The present invention relates to a method for manufacturing a silicon single crystal ingot that improves the performance.

[0002]

2. Description of the Related Art Generally, a silicon wafer used for a semiconductor device is manufactured by cutting out a silicon single crystal ingot. The silicon single crystal is mainly made of polysilicon by a Czochralski method (hereinafter, referred to as a CZ method). It is manufactured by

For example, in the CZ method, polysilicon as a raw material supplied into a quartz glass crucible is heated and melted, and the tip of a seed crystal is brought into contact with the silicon melt to be blended.
It grows and pulls up a silicon single crystal ingot.

[0004] In such a CZ method, the charge amount of the raw material polysilicon initially supplied is constant in many CZ methods, and the following problems have been caused in recent years as the diameter of silicon single crystal ingots has increased. It has occurred.

[0005] As shown in FIG.
Inch Silicon Single Crystal Ingot Ig₈Is silicon
Straight body Ig that can be used as wafer_8sIs relatively long,
Head Ig formed at the beginning of pulling_8hAnd pulling up late
Tail part Ig formed in_{8 t}Is relatively short. Therefore,
One silicon single crystal ingot Ig₈Many pieces from
Of silicon wafer can be cut out. But the figure
As shown in Fig. 8, silicon with a diameter of 300 mm (12 inches)
Single crystal ingot Ig₁₂Pull up the straight body Ig
_12sIs short and the head Ig_8hAnd tail Ig_8tIs
become longer. Therefore, it is possible to cut out silicon wafers.
Unable head Ig_8h, Tail Ig _8tMany in the formation of
It takes a lot of time and productivity is low.

In addition, as the diameter of the silicon single crystal ingot increases, the weight of the pulled silicon single crystal ingot increases, so that the neck portion breaks during the pulling from the quartz glass crucible and the silicon single crystal ingot falls. In some cases, dropping a silicon single crystal ingot has been an issue.

[0007] In Japanese Patent Application Laid-Open No. 3-295893, after a dislocation is eliminated by a dash neck portion, a so-called cone portion which expands to a desired diameter is once reduced in diameter to form a crack portion, and the crack portion is formed. Is provided with a gripping means for gripping the single crystal ingot by hooking a claw-shaped locking member, and raising the gripping means to pull up the single crystal ingot. However, in the method of this disclosure, it is necessary to form a crack portion for holding in a single crystal ingot, but forming such a crack portion in a predetermined shape may cause a reduction in yield in a manufacturing process. In addition, the temperature pattern during crystal growth and the need to change the pulling speed in order to form the cracked portion need to be changed, which causes a problem that the pulling operation is complicated and the productivity is reduced. Due to the thermal stress when the diameter is reduced, dislocation may occur or polycrystallization may occur.

In Japanese Patent Application Laid-Open No. 7-138089, a dash neck portion is cooled or heated during the growth of a single crystal to provide a maximum tensile strength of 600 to 80 at the portion.
A method of maintaining the temperature at about 0 ° C. is disclosed. However, in the method of this disclosure, an increase in holding weight cannot be expected despite the complicated temperature control and mechanism.

Further, in Japanese Patent Application Laid-Open No. 7-172981, a grip means having a plurality of arms which can be opened and closed by a pneumatic cylinder is arranged so as to surround the single crystal ingot from the direction of the growth axis of the single crystal. The ingot is gripped by operating the cylinder and pressing the grips provided at the tip end of each of the plurality of arms against the straight body of the single crystal ingot, and the single crystal is pulled up by raising the gripping means. A method is disclosed.

However, when the straight body of the single crystal ingot is gripped by the gripping means, the disclosed method requires a driving device such as an air cylinder for pressing from the lateral direction. Will be expensive. In addition, it is necessary to design a strong overall structure capable of withstanding a large lateral load applied to the drive device, which not only increases the weight of the entire device, but also requires that these components be supported by a single shaft. Was.

Japanese Patent Application Laid-Open No. H10-324593 has a support means attached to a pulling wire, and a plurality of support rings suspended at the support means are arranged at equal intervals to be rotatable. A method is disclosed in which a straight body of a single crystal ingot is gripped by a gripping means formed by an eccentric cam, and the single crystal is pulled by raising the gripping means. However, the method of this disclosure requires a mechanism for suspending the support ring and a mechanism for operating the gripping means, which results in a complicated structure and an expensive apparatus.

Therefore, none of the above methods is a method of manufacturing a silicon single crystal ingot using low productivity, an easy method, and a simple structure manufacturing apparatus.

[0013]

Therefore, there has been a demand for a method of manufacturing a silicon single crystal ingot which has good productivity and can manufacture a large-diameter and heavy silicon single crystal ingot by an easy method.

The present invention has been made in view of the above-mentioned circumstances, and provides a method of manufacturing a silicon single crystal ingot which has high productivity and can manufacture a large-diameter and heavy silicon single crystal ingot by an easy method. The purpose is to provide.

[0015]

Means for Solving the Problems According to the first aspect of the present invention, there is provided a crucible provided in a chamber, and a raw material polysilicon filled in the crucible is heated and melted. In a method for producing a silicon single crystal ingot using a CZ method in which a seed crystal is immersed in a melt and a silicon single crystal is pulled up, when growing a specific portion of a silicon single crystal ingot to be grown, The gist of the present invention is to provide a method of manufacturing a silicon single crystal ingot characterized by increasing the tensile strength at a specific portion by increasing the impurity concentration at a specific portion.

According to the second aspect of the present invention, during the step of forming the tail portion by reducing the diameter of the silicon single crystal ingot to be grown, the strength of the tail portion is increased by increasing the impurity concentration in the tail portion, Thereafter, the method is a method for manufacturing a silicon single crystal ingot according to claim 1, wherein the silicon single crystal ingot is separated from the polysilicon.

According to the third aspect of the present invention, during the step of forming the neck portion of the silicon single crystal ingot by reducing the diameter of the grown silicon single crystal ingot, the impurity concentration in the neck portion is increased to increase the neck portion. The gist of the present invention is to provide a method for manufacturing a silicon single crystal ingot according to claim 1, wherein the strength of the silicon single crystal ingot is increased.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a silicon single crystal ingot according to any one of the first to third aspects, wherein the impurity is nitrogen.

According to a fifth aspect of the present invention, the supply of the impurities is performed via a dopant supply pipe extending from outside the chamber to near the silicon melt surface when the tail portion is formed. The gist is that the method is a method for manufacturing a silicon single crystal ingot according to item 4.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method for manufacturing a silicon single crystal ingot according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a single crystal pulling apparatus 1 for a CZ method used in a method of manufacturing a silicon single crystal ingot according to the present invention. The raw material polysilicon housed in a chamber 2 is melted into a silicon melt M. It has a quartz glass crucible 3, a graphite crucible 4 holding the quartz glass crucible 3, and a heater 5 surrounding the graphite crucible 4. The graphite crucible 4 penetrates the chamber 2, is connected to a crucible rotation motor 6, is rotated, and is attached to a crucible rotation shaft 8 that is raised and lowered by a lifting device 7.

Further, a pulling region is surrounded above the quartz glass crucible 3 to prevent heat radiation from the silicon melt M,
Further, a radiation shield 9 for controlling a flow path of an inert gas, for example, argon flowing in the chamber 2 is provided.

Further, a doping agent supply pipe 10 is provided in which the lower end opening 10a reaches near the lower portion of the quartz glass crucible 3 and the upper end opening 10b reaches the through hole 11 provided in the chamber 2. Agent injection pipe 1
Numeral 0 penetrates the through-hole 11 so as to be able to move up and down in an airtight manner, and a lid 12 is detachably provided at the upper end opening 10b.

Above the quartz glass crucible 3, there is provided a pulling wire 14 to which a seed chuck 13 for holding a seed crystal S for pulling a single crystal is attached. The wire 14 is moved up and down by a wire reel rotating device 15 provided outside the chamber 2.

Further, on the upper outer wall of the chamber 2, there is provided a monitoring window 16 capable of transmitting light by closing the through hole with heat resistant glass.

The single crystal pulling apparatus 1 has a control unit 17 which controls a heater 5c for controlling the amount of electric power supplied to the heater 5 for controlling the temperature of the silicon melt M, and a quartz unit. The crucible motor controller 6c for controlling the number of rotations of the glass crucible 3, the elevating device controller 7c for controlling the height of the quartz glass crucible 3, the reel rotation control device 15c for controlling the pulling speed and the number of rotations of the grown crystal, etc. .
By controlling the heater controller 5c, the crucible motor controller 6c, the elevating device controller 7c, and the reel rotation control device 15c based on the output from the control device 17, the pulling conditions are changed, and the diameter of the silicon single crystal ingot Ig is controlled. Neck I
g _n, head Ig _h, to form the cylindrical body portion Ig _s tail Ig _t.

During the single crystal pulling process, the controller 17
Control of the heater controller 5c, crucible motor controller 6c, lifting device controller 7c, reel rotation control device 15c, and argon supply control device controller (not shown) according to the control procedure programmed in the control device 17 in advance. This is performed by an input from an input unit 18 provided in the control device 17 as necessary.

Next, a method for pulling a single crystal according to the first embodiment will be described.

As shown in FIG. 1, the raw material polysilicon is put into the quartz glass crucible 3, and the heater controller 5c, the crucible motor controller 6c, the elevator controller 7c, the reel rotation The controller 15c and the argon supply controller are controlled.
As a result, argon was allowed to flow into the chamber 2 from above the chamber 2, the quartz glass crucible 3 was heated by the energization of the heater 5, and coupled to the crucible rotation motor 6 by the energization of the crucible rotation motor 6. The quartz glass crucible 3 is rotated by rotating the crucible rotation shaft 8.

In this state, the doping agent supply pipe 10
Is in the ascending position, and the lower end opening 10a is almost ascended to the horizontal portion 9h of the radiation shield 9.

The control device 17 controls the reel rotation control device 15c to operate the wire reel rotation device 15 to lower the wire 14 so that the lower end of the seed crystal S is brought into contact with the silicon melt M in the quartz glass crucible 3. after immersion, it is raised by the wire reel rotation device 15, a neck portion Ig _n is a small diameter portion of the first single crystal is grown. That is, the controller 17 controls the heater controller 5c to lower the temperature of the silicon melt M, or controls the reel rotation controller 15c to increase the pulling speed so that the diameter of the seed crystal S is smaller than the diameter of the seed crystal S. to form a neck portion Ig _n.

Next, by controlling the reel rotation control device 15c, the pulling speed is reduced, and the silicon single crystal ingot I
made to increase the diameter of g, then to a diameter of the silicon to be manufactured single crystal ingot Ig to form a sharply increased diameter head portion Ig _h, then by the pulling speed constant, a single crystal (the straight body portion of constant diameter Ig _s ).

After the lapse of a predetermined time, the reel rotation control device 15c is controlled by the output from the control device 17,
Change the pulling conditions, by controlling the diameter of a silicon single crystal ingot Ig, specific sites of the silicon single crystal ingot Ig, for example, initiate the formation of the tail portion Ig _t.

[0034] Prior to the step of forming the tail portion Ig _t, lowers the doping agent dispenser pipe 10 to the lower end opening portion 10a close to the silicon melt M, the upper end opening 10
The lid 12 attached to b is removed, and a small amount of a dopant, for example, silicon nitride powder (Si ₃ N ₄ ) D is continuously doped into the silicon melt M through the dopant charging pipe 10.

The Si ₃ N ₄ in the silicon melt M controls the reel rotation control unit 15c while being doped with slow pulling rate, allowed reducing the diameter of the silicon single crystal ingot Ig, forms the tail portion Ig _t I will do it. Tail I
The length of g _t is a predetermined length, for example When turned 10 cm,
The single crystal ingot Ig is separated from the silicon melt M by controlling the reel rotation control device 15c to rapidly increase the pulling speed. Tail Ig _t is increased strength is due Pin'ingu action of dopant, even the silicon single crystal ingot Ig halfway pulling the single crystal separately from the silicon melt M, the silicon single crystal Ig dislocation hardly occurs.

[0036] Thus, to exit in the middle step of forming the tail portion Ig _t, it is possible to shorten the single crystal pulling time, it is possible to improve the productivity.

The increase in the strength of the nitrogen-doped silicon single crystal is considered as follows. That is, when nitrogen is present in the silicon melt M in a molecular state, the moving speed of molecular nitrogen in the crystal is higher than the speed of dislocation, and the nitrogen molecule has a property of shifting toward the strain around the dislocation. Therefore, it catches up with the dislocation, in order to enhance the crystal changes its bonding state of molecules in the SiN _x shape.

[0038] Since the tail portion Ig _t is not used for an electronic device as a silicon wafer, a dopant is not limited to Si ₃ N _4, as long as it improves the strength of the single crystal, IIIb group (B , Al, Ga, etc.), I
Vb group (C, Ge, etc.), Vb group (P, etc.), O, F, etc. may be used.

Further, in the method of supplying the dopant, an opening / closing valve capable of controlling the flow of the dopant is provided above the pipe for introducing the dopant, and the opening / closing valve is controlled by the control device 17;
The doping agent may be automatically supplied to the raw material melt.

Next, a second embodiment of the method for manufacturing a silicon single crystal ingot according to the present invention will be described.

As described in the first embodiment, the second embodiment is applied to increase the crystal strength by doping nitrogen into a silicon single crystal, and is applied to a specific portion of a silicon single crystal ingot, for example, At the time of crystal growth of a neck portion which is a small diameter portion of a single crystal formed at a lower end portion of a seed crystal,
This is a method of manufacturing a silicon single crystal ingot in which the neck portion is doped with nitrogen to improve the strength of the neck portion.

For example, the same parts as those of the first embodiment will be denoted by the same reference numerals. As shown in FIG. 2, the single crystal pulling method used in the method of manufacturing a silicon single crystal ingot according to the present embodiment will be described. The upper device 21 includes a quartz glass crucible 3 which is housed in the chamber 2 and melts polysilicon to form a silicon melt M, a graphite crucible 4 holding the quartz glass crucible 3, and a heater 5. The graphite crucible 4 penetrates the chamber 2, is connected to a crucible rotation motor 6, is rotated, and is attached to a crucible rotation shaft 8 that is raised and lowered by a lifting device 7.

A radiation shield 22 is provided above the quartz glass crucible 3. Further, the radiation shield 22 is provided with an inner cylinder 23 substantially similar in shape to the radiation shield 22, and is provided with a nitrogen gas flow. A passage 24 is formed. The nitrogen gas outlet 24o provided in the nitrogen gas flow path 24 is located near the neck Ig _2n , and the nitrogen gas inlet 24i is a ring-shaped nitrogen gas inlet disposed above the radiation shield 22. 25. The nitrogen gas supply port 25 communicates with a nitrogen gas supply pipe 26 and is connected to a nitrogen gas supply device (not shown) via a nitrogen gas electromagnetic on-off valve 27 controlled by the controller 17. .

Further, an argon supply pipe 28 for supplying argon to the chamber 2 is provided.
7 is connected to an argon supply device (not shown) through an argon on-off valve 29 controlled by.

Next, a method for pulling a single crystal according to the second embodiment will be described.

As shown in FIG. 2, the raw material polysilicon is put into the quartz glass crucible 3, and the heater controller 5c, the crucible motor controller 6c, the elevator controller 7c, the reel rotation The controller 15c and the argon supply controller are controlled.
Thereby, argon is caused to flow into the chamber 2 from above the chamber 2 to make the inside of the chamber 2 an argon atmosphere,
The quartz glass crucible 3 is heated by the urging of the heater 5, and the crucible rotating shaft 8 connected to the crucible rotating motor 6 is rotated by the urging of the crucible rotating motor 6 to rotate the quartz glass crucible 3.

Further, the controller 17 opens the nitrogen on-off valve 27 for nitrogen gas to supply nitrogen gas from the nitrogen gas supply device to the nitrogen gas supply pipe 26 and the nitrogen gas supply port 2.
5. Nitrogen gas is blown out from the nitrogen gas outlet 24o through the nitrogen gas inlet 24i and the nitrogen gas flow path 24, and the vicinity of the region where the seed crystal S is immersed in the silicon melt M (the neck portion Ig _2
( near where _n is formed) in a nitrogen gas atmosphere.

By supplying a nitrogen gas atmosphere only in the vicinity where the neck portion Ig _2n is formed, the supply amount of the nitrogen gas into the chamber 2 is suppressed, and the nitriding of the silicon melt surface and the carbon member are minimized. Can be suppressed.

Thereafter, the controller 17 controls the reel rotation controller 15c to operate the wire reel rotor 15 to lower the wire 14 so that the lower end of the seed crystal S is melted in the silicon glass crucible 3. After immersion in M
Is raised by the wire reel rotation device 15, a neck portion Ig _2n is a small diameter portion of the first single crystal is grown.

In the step of forming the neck portion Ig _2n ,
Since the vicinity of the neck Ig _2n is in a nitrogen atmosphere, the grown neck Ig _2n is a silicon single crystal having a high nitrogen concentration.

After the neck Ig _2n is formed, the controller 17 closes the nitrogen gas electromagnetic on-off valve 27,
The supply of the nitrogen gas from the nitrogen gas supply device to the nitrogen gas outlet 24o is stopped, and the entire inside of the chamber 2 including the vicinity of the neck Ig _2n is brought into an argon atmosphere.

[0052] Then at slow pulling rate by controlling the reel rotation control unit 15c, made to increase the diameter of the single crystal Ig _2, the head portion Ig _2h then suddenly expanded to then be produced in single crystal Ig ₂ diameter Is formed, and then the pulling speed is made constant to obtain a single crystal having a constant diameter (the straight body portion Ig).
_2s ). After a lapse of a predetermined time, the pulling conditions are changed by controlling the reel rotation control device 15c based on the output from the control device 17, the diameter of the single crystal Ig is controlled, and the tail portion Ig _2t is formed. Complete the pulling of the crystal.

[0053] In pulling step of the silicon single crystal ingot Ig _2, although its weight increases with the growth of silicon single crystal ingot Ig _2, neck Ig
_Since the nitrogen concentration of _2n is large, the neck Ig
_n has an increased tensile strength, and can sufficiently withstand the weight of the silicon single crystal ingot Ig ₂ during the pulling of the single crystal.

Therefore, the silicon single crystal ingot Ig ₂
During the pulling process, the neck portion Ig _2n is not broken due to the weight of the silicon single crystal ingot Ig ₂ , and the silicon single crystal ingot Ig ₂ does not fall into the quartz glass crucible 3. A heavy silicon single crystal ingot can be pulled.

In the second embodiment, in the neck portion forming step, a nitrogen gas is supplied into the argon atmosphere in the vicinity of the neck portion forming region, but the supply of argon is stopped. The neck portion may be formed in a nitrogen atmosphere by supplying only a gas.

[0056]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Test 1 (Example 1) (1) Purpose: To investigate the relationship between the nitrogen concentration and the dislocation density in a silicon single crystal.

(2) Method: Using a method of manufacturing a silicon single crystal ingot according to the present invention as shown in FIGS. 3A and 3B, introducing Si ₃ N ₄ powder as a dopant and pulling up. On the way, the single crystal ingot was cut off from the silicon melt (Example 1). A sample was cut out from the single crystal ingot, the dislocation density was observed by an electron microscope after etching, and the nitrogen concentration was observed by SIMS.

(3) Results: The results of Example 1 are shown in FIG. From Example 1, it was found that the dislocation density decreased as the nitrogen concentration increased, and the dislocation density did not decrease so much from about 10 ¹⁵ Atoms / cm ³ . From this result, it is considered that the strength of the nitrogen-doped silicon single crystal is increased by the pinning action, and dislocation is less likely to occur.

2. Test 2 (Example 2) (1) Purpose: To form a tail portion in a silicon single crystal ingot.

(2) Method: In the same manner as in Test 1,
Pull an 8-inch silicon single crystal. At the time of forming the tail portion, 2 g of Si ₃ N ₄ powder was introduced at a time, and when the length of the tail portion became about 10 cm, the single crystal was separated from the silicon melt (Example 2). The pulling time was checked. In addition, a sample was cut out from the single crystal ingot (the lower part of the straight body), and after etching, the dislocation density was observed with an electron microscope.

(3) Result: As shown in FIG. 6, in the conventional example, it was necessary to form a tail portion of about 40 cm.
As shown in FIG. 2, in Example 2, the length was about 10 cm, and the formation time of the tail part could be reduced to about 1/4. Example 2
Has no difference from the dislocation density of the conventional example, and it has been found that there is no problem even if the single crystal is separated from the silicon melt during the formation of the tail portion as in the example, and that the formation time of the tail portion can be shortened.

3. Test 3 (Example 3) (1) Purpose: Using an optimal silicon single crystal ingot pulling apparatus, the tensile strength of a nitrogen-doped neck portion is measured by the method for producing a silicon single crystal ingot according to the present invention.

(2) Method: Using the method of manufacturing a silicon single crystal ingot according to the present invention as shown in FIG. 2, 60 liters of argon per minute and 30 liters of nitrogen gas per minute are supplied into the chamber. Nitrogen gas at 10 per minute
Liters are blown out from the nitrogen gas outlet and the furnace pressure is reduced to 50
After forming the neck portion at torr, the supply of nitrogen gas was stopped, and the flow rate of argon was increased to 100 liters per minute to pull up a silicon single crystal (Example 3).

The diameter of the neck is 4 mm and the length is 300 mm
The seed drawing process was performed. The neck portion of the pulled silicon single crystal ingot was cut out and the tensile strength was measured.

(3) Result: The tensile strength of Example 3 was 76
kg / mm ² (at 900 ° C.). In addition, slight adhesion of silicon nitride was observed on the carbon heater and the protection cylinder outside the heater, but the amount was smaller than that of Example 4 and was in a range without any problem.

4. Test 4 (Example 4) (1) Purpose: Using a commonly used silicon single crystal ingot pulling apparatus, the tensile strength of a nitrogen-doped neck portion is measured by the method for producing a silicon single crystal ingot according to the present invention.

(2) Method: Using a generally used silicon single crystal pulling apparatus, argon is supplied into the furnace from above the pulling chamber at a rate of 50 liters per minute, nitrogen gas at a rate of 50 liters per minute, and a furnace pressure of 50 torr. Then, after forming the neck portion, the supply of nitrogen gas was stopped, and the flow rate of argon was increased to 100 liters per minute to pull up the silicon single crystal (Example 4). Neck diameter 4mm, length 300
The seed drawing process was performed in mm.

The neck portion of the pulled silicon single crystal ingot was cut out and the tensile strength was measured.

(3) Result: The tensile strength of Example 4 was 75
kg / mm ² (at 900 ° C.). In addition, some adhesion of silicon nitride was observed on the carbon heater and the protection cylinder outside the heater, but this was within the range without any problem.

5. Test 5 (conventional example) (1) Purpose: Using the same silicon single crystal ingot pulling apparatus as in Test 4, forming a neck portion without doping with nitrogen by a method for manufacturing a silicon single crystal ingot, and tensile strength of the neck portion Is measured.

(2) Method: A silicon single crystal ingot was pulled up in the same manner as in Test 4 except that nitrogen was not supplied and only argon was supplied, and argon was supplied at 100 liters per minute (conventional example). . The neck portion of the pulled silicon single crystal was cut out and the tensile strength was measured.

(3) Result: The tensile strength of the conventional example is 70 k
g / mm ² (at 900 ° C.), which is about 90%
It was found that it had only the strength of

[0073]

According to the method for manufacturing a silicon single crystal ingot according to the present invention, a silicon single crystal ingot can be manufactured with good productivity and a large diameter and heavy silicon single crystal ingot by an easy method. A method can be provided.

That is, when growing a specific portion of the silicon single crystal ingot to be grown, the method is a method of manufacturing a silicon single crystal ingot that increases the tensile strength of the specific portion by increasing the impurity concentration of the specific portion. By applying to strengthening of the single crystal, during the pulling of the single crystal, the single crystal can be cut off from the silicon melt and the step of forming the tail part can be completed in the middle, and by applying to strengthening the neck part, When pulling a silicon single crystal ingot, a neck portion is not broken, and a large-diameter and heavy silicon single crystal ingot can be pulled with good productivity.

Further, during the step of forming the tail portion by reducing the diameter of the silicon single crystal ingot to be grown, the impurity concentration in the tail portion is increased to increase the strength of the tail portion, and thereafter, the silicon single crystal ingot is increased. Is separated from the polysilicon, so the tail part has increased strength. Even if the single crystal is separated from the silicon melt during the pulling of the single crystal, dislocations are unlikely to occur in the single crystal, and the tail part formation process is completed halfway Thus, the single crystal pulling time can be shortened, and the productivity can be improved.

Further, during the step of forming the neck portion of the silicon single crystal ingot by reducing the diameter of the silicon single crystal ingot to be grown, the impurity concentration in the neck portion is increased to increase the strength of the neck portion. This allows
Can withstand the weight of the silicon single crystal ingot during single crystal pulling, and the neck of the silicon single crystal ingot falls during the pulling process due to the weight of the silicon single crystal ingot and falls into the quartz glass crucible. And a large-diameter, large-weight silicon single crystal ingot can be pulled safely and with good productivity.

Since the impurity is nitrogen, the strength of the tail portion can be increased without impairing the characteristics of the silicon single crystal ingot.

Further, since the supply of the impurities is performed through the dopant supply pipe extending from the outside of the chamber to the vicinity of the silicon melt surface when the tail portion is formed, the dopant can be accurately supplied to the silicon melt. In addition, the inside of the chamber is not contaminated with the dopant.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a silicon single crystal pulling apparatus used in a method for manufacturing a silicon single crystal ingot according to the present invention.

FIG. 2 is a schematic view of another embodiment of a silicon single crystal pulling apparatus used in the method for manufacturing a silicon single crystal ingot according to the present invention.

FIGS. 3A and 3B are explanatory views of an embodiment of a method for manufacturing a silicon single crystal ingot according to the present invention.

FIG. 4 is a result diagram showing test results of an example of the method for manufacturing a silicon single crystal ingot according to the present invention.

FIG. 5 is an explanatory diagram of a silicon single crystal ingot showing test results of an example of a method for manufacturing a silicon single crystal ingot according to the present invention.

FIG. 6 is an explanatory view of a silicon single crystal ingot manufactured by a conventional method of manufacturing a silicon single crystal ingot.

FIG. 7 is an explanatory diagram of an 8-inch diameter silicon single crystal ingot manufactured by a general method for manufacturing a silicon single crystal ingot.

FIG. 8 is an explanatory diagram of a silicon single crystal ingot having a diameter of 300 mm manufactured by a general method for manufacturing a silicon single crystal ingot.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Single crystal pulling apparatus 2 Chamber 3 Quartz glass crucible 4 Graphite crucible 5 Heater 5c Heater controller 6 Motor for crucible rotation 6c Crucible motor controller 7 Elevating device 7c Elevating device controller 8 Crucible rotating shaft 9 Radiation shield 9h Horizontal part 10 Dope Agent injection pipe 10a Lower end opening 10b Upper end opening 11 Through hole 12 Lid 13 Seed chuck 14 Wire 15 Wire reel rotating device 15c Reel rotation controlling device 16 Monitoring window 17 Control device 18 Input means 21 Single crystal pulling device 22 Radiation Shield 23 Inner tube 24 Nitrogen gas flow path 24i Nitrogen gas inlet 24o Nitrogen gas outlet 25 Nitrogen gas inlet 26 Nitrogen gas supply pipe 27 Nitrogen gas solenoid valve 28 Argon supply pipe 29 Argon solenoid valve Ig Silicon single crystal ingot Ig _n ne Click portion Ig _h head Ig _s straight body Ig _t tail portion Ig ₂ silicon single crystal ingot Ig _2h head Ig _2t tail portion Ig _2n neck D dopant M silicon melt S seed

Continued on the front page (72) Inventor Ryuji Takeda 686-1, Higashiko, Seikocho, Kitakanbara-gun, Niigata 5 F-term in Toshiba Ceramics Co., Ltd. 4G077 AA02 BA04 CF10 EA10 EB01 EB04 EH05 HA12

Claims (5)

[Claims] 1. A crucible installed in a chamber and a heater for heating a raw material polysilicon filled in the crucible to melt the seed polysilicon, dipping a seed crystal in the melt and drawing a silicon single crystal. In the method for producing a silicon single crystal ingot using the increasing CZ method, when growing a specific part of the silicon single crystal ingot to be grown, the tensile strength of the specific part is increased by increasing the impurity concentration of the specific part. Of producing a silicon single crystal ingot. 2. The process of reducing the diameter of a silicon single crystal ingot to be grown to form a tail portion, wherein the concentration of impurities in the tail portion is increased to increase the strength of the tail portion. 2. The method according to claim 1, wherein a crystal ingot is separated from the polysilicon. 3. A method of forming a neck portion of a silicon single crystal ingot by reducing the diameter of the silicon single crystal ingot to be grown to increase the strength of the neck portion by increasing an impurity concentration in the neck portion. The method for producing a silicon single crystal ingot according to claim 1, wherein: 4. The method for manufacturing a silicon single crystal ingot according to claim 1, wherein said impurity is nitrogen. 5. The method according to claim 2, wherein the supply of the impurities is performed via a dopant supply pipe extending from outside the chamber to near the silicon melt surface when the tail portion is formed.
Or the method for producing a silicon single crystal ingot according to 4.