KR101472354B1 - Methof for manefacturing silicon single crystal and silicon single crystal ingot - Google Patents

Abstract

According to an embodiment, provided is a method of growing a single crystal of silicon, which includes a) a step of preparing molten silicon in a crucible, b) a step of supplying a dopant to the molten silicon, and c) a step of dispersing the dopant into the molten silicon and discharging a dopant oxide from the periphery of the molten silicon, wherein a rotation speed of the crucible in step (c) is 0.1 to 0.5 times greater than a rotation speed of the crucible in step (b).

Description

TECHNICAL FIELD [0001] The present invention relates to a silicon single crystal ingot and a method for growing the single crystal silicon ingot. BACKGROUND ART < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of growing a silicon single crystal, and more particularly, to an improvement in efficiency when a dopant is doped in a silicon melt.

Background Art [0002] Silicon (Si) wafers are widely used as materials for manufacturing semiconductor devices. The silicon wafer is excellent in the purity and crystallization characteristics of a region where the semiconductor is directly formed, and is advantageous in improving the yield and device characteristics of a semiconductor device.

A typical silicon wafer includes a single crystal growth step for making a single crystal ingot, a slicing step for obtaining a thin disk-like wafer by slicing a single crystal ingot, a damaging (Damage) caused by mechanical processing remaining on the wafer, A grinding step of removing cracks and distortion of the wafer obtained by the slicing step, a polishing step of mirror-polishing the wafer, a polishing step of polishing the polished wafer, And a cleaning process for removing the abrasive or foreign substance adhered to the polishing pad.

In the process of growing and pulling a single crystal by the Czochralski method (hereinafter referred to as a 'CZ method'), a dopant may be added to the silicon melt before the growth of the single crystal to give a resistivity to the single crystal.

After the doping process, a doping stabilization process is performed for a predetermined period of time. In the doping stabilization process, the efficiency is reduced due to volatility of the dopant from the silicon melt or a dopant oxide is generated in the process chamber, .

The embodiment is for eliminating the above-described problem, and it is intended to increase the doping efficiency of the dopant doped in the silicon melt and to reduce the silicon oxide in the step of growing the silicon single crystal ingot.

(A) preparing a silicon melt in a crucible; (B) supplying a dopant to the silicon melt; And (c) diffusing the dopant in the silicon melt and exhausting a dopant oxide around the silicon melt. In the step (c), the rotation speed of the crucible is adjusted in the step (b) Wherein the growth rate of the silicon single crystal is 0.1 to 0.5 times the rotation speed.

the magnetic field applied to the crucible in step (b) is turned off, and the magnetic field applied to the crucible in step (c) may be turned on.

In the step (c), the height of the crucible may be lower than the height of the crucible in the step (b).

the distance from the upper heat insulating portion to the surface of the silicon melt in the step (c) may be 20% to 40% larger than the distance from the upper heat insulating portion to the surface of the silicon melt in the step (b).

the inert gas may be supplied between the upper heat insulating portion and the silicon melt in the step (c).

The inert gas may be supplied at 80 to 120 lpm.

The method for growing a silicon single crystal may further include the step of further supplying the dopant to the silicon melt after the step (c).

Another embodiment provides a silicon monocrystal ingot produced by a growth method and having a longitudinal resistance of 3 milliohms or less.

The resistance variation of the silicon single crystal ingot may be 1.5 milliohms to 3 milliohms.

The silicon single crystal growth method and the silicon single crystal ingot according to the embodiments can reduce the dopant oxide in the doping stabilization process and improve the quality of the silicon single crystal ingot and reduce the volatilization amount of the dopant to increase the doping efficiency.

1 is a view showing an embodiment of a silicon single crystal ingot growing apparatus,
2 is a flowchart of one embodiment of a method for growing a silicon single crystal ingot,
3A to 3D are diagrams showing a growth process of a silicon single crystal ingot,
4 is a view showing a grown silicon single crystal ingot,
5 is a graph showing an increase in resistivity with a decrease in dopant in a silicon melt,
FIG. 6 is a diagram showing a decrease in specific resistance due to addition of a doping stabilization process. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The same components as those in the prior art are denoted by the same names and the same reference numerals for convenience of description, and a detailed description thereof will be omitted.

1 is a view showing an embodiment of a silicon single crystal ingot growing apparatus.

The apparatus 100 for manufacturing a silicon single crystal ingot according to this embodiment includes a chamber 10 in which a space for growing a silicon single crystal ingot from a silicon melt is formed, A heating unit 20 for heating the crucibles 60 and 65 and a crucible 60 for cutting off the heat of the heating unit 20 toward the silicon single crystal ingot (Not shown) for fixing a seed (not shown) for growing the silicon single crystal ingot and a seed chuck (not shown) for moving the silicon single crystal ingot upward Means.

The apparatus 100 for manufacturing a silicon single crystal ingot includes support means 50 for supporting and rotating and elevating the crucibles 60 and 65 and heating means 20 Side heat insulating portion 31 for blocking the heat of the silicon single crystal ingot and a cooling pipe 70 for cooling the silicon single crystal ingot.

The crucible is located in a central region of the chamber (10). The crucible is in the shape of a generally concave vessel so that the silicon melt can be received. The crucible includes a quartz crucible 60 in direct contact with the silicon melt Si and a graphite crucible 65 that surrounds the quartz crucible 60 and supports the quartz crucible 60. [ .

The side surface of the crucible is provided with a heating unit 20 for emitting heat toward the crucible and the side heat insulating unit 31 is provided between the heating unit 20 and the inner wall of the chamber 10 .

The upper heat insulating portion 32 extends from the inner wall of the chamber 10 toward the interface between the silicon melt and the single crystal ingot grown from the silicon melt. However, the end portion of the upper heat insulating portion 32 is extended within a range that the argon gas flows through the space between the end portion of the upper heat insulating portion 32 and the interface.

Further, the end portion of the upper heat insulating portion 32 can be disposed surrounding the ingot being grown. That is, the upper heat insulating portion 32 includes a heating chamber 13 in which the silicon melt is heated and a monocrystalline ingot is grown from the silicon melt, and a cooling chamber (not shown) in which the monocrystalline ingot is cooled 14).

The moving means of the silicon single crystal ingot includes a seed cable 42 and a driving motor (not shown). By pulling the seed cable 42 by the driving motor, the seed chuck (not shown) and the growing monocrystalline ingot in the seed chuck can be pulled together. The monocrystalline ingot begins to grow from the neck as shown and grows through the shoulder through the body.

The supporting means 50 includes a supporting portion for supporting the crucible and a driving motor (not shown) for providing power for rotating and lifting the crucible. The support portion supports the bottom surface of the crucible below the crucible, and the driving motor rotates and lifts the support portion so that the crucible is rotated and elevated.

The cooling pipe 70 has a hollow cylindrical shape which is long in the vertical direction as a whole. The cooling pipe 70 is fixed to the upper surface of the chamber 10 corresponding to the upper side of the single crystal ingot.

Inside the cooling tube 70, a flow path for water for cooling the single crystal ingot is formed. During the cooling process of the single crystal ingot, the single crystal ingot is located inside the cooling tube 70 and the single crystal ingot is cooled in such a manner that water flows through the cooling tube 70 have.

FIG. 2 is a flow chart of one embodiment of a method for growing a silicon single crystal ingot, and FIGS. 3A to 3D are views showing a step of growing a silicon single crystal ingot.

Hereinafter, a method of growing a silicon single crystal ingot according to an embodiment will be described.

First, as shown in FIG. 3A, a silicon melt is prepared in the crucible 60, and silicon (Si) may be injected into the crucible 60 and heated and melted (S110). At this time, the heat released from the heating portion is concentrated in the crucible 60, so that the silicon melt contained in the crucible 60 can be melted.

Then, as shown in FIG. 3B, a dopant may be supplied to the silicon melt (Si) to be doped. In this case, a magnetic field may not be applied to the crucible (S120). Elements such as arsenic (As) can lower the resistivity and can be used as a dopant. The doping process may be conducted at a temperature of 1460 to 1480 degrees Celsius for about 20 minutes.

In this case, a magnetic field can be applied to the crucible and the height of the crucible can be lowered in the doping step of the dopant described above (S130). The dopant described above can be diffused in the silicon melt to stabilize the dopant, and at this time, the dopant oxide around the silicon melt can be exhausted.

The dopant stabilization process can proceed for about 20 minutes at a temperature of about 1420 degrees Celsius.

A magnetic field that is turned off in the doping step of the dopant can be turned on in the stabilization of the dopant and the oxide exhaust process and can be performed by turning off and on the magnetic field applying unit 150.

The lowering of the crucible can be performed by the action of the above-mentioned supporting means. If the height of the crucible is lowered in the stabilizing process of the dopant, the height of the surface of the silicon melt can also be lowered. 3C shows the doping step and FIG. 3D shows the doping stabilization step, wherein the distance from the upper insulating portion 32 to the surface of the silicon melt can be greater in the doping stabilization step than in the doping step.

The distance h2 from the upper heat insulating portion 32 to the surface of the silicon melt at the doping stabilization step may be larger than the distance h1 from the upper heat insulating portion 32 to the surface of the silicon melt at the doping step, The distance h2 from the upper heat insulating portion 32 to the surface of the silicon melt in the doping stabilization step is 20% to 40% larger than the distance d1 from the upper heat insulating portion to the surface of the silicon melt in the doping step have.

If the distance h2 is too large in the doping stabilization step, the volatilization of the material may be too much, and if the distance h2 is too small, the dopant oxide may not be easily exhausted.

The crucible may be rotated by the action of the support means in the doping process and the doping stabilization process. The rotation speed of the crucible may be slower in the doping stabilization process than in the doping process. More specifically, in the doping stabilization process shown in FIG. 3D, the rotational speed (b rpm) of the crucible 60 is 0.1 to 0.5 times the rotational speed (a rpm) of the crucible 60 in the doping process shown in FIG. .

If the above-mentioned rotation speed is too high, the thermal flow may not sufficiently occur in the crucible, and if it is too slow, it may be difficult to supply heat to the crucible.

In order to exhaust the dopant oxide in the doping stabilization process shown in FIG. 3D, an inert gas such as argon (Ar) may be supplied between the upper heat insulating portion 32 and the silicon melt. The inert gas may be supplied at 80 lpm (Liter per Million) to 120 lpm, which can exhaust the dopant oxide without reacting with the gaseous dopant oxide inside the chamber.

The dopant may be volatilized within the chamber or otherwise removed through the exhaust, wherein the dopant oxide may be present on the surface of the silicon melt or between the upper insulating portion and the silicon melt.

After the doping stabilization step, the dopant may be redoped in the silicon melt (S140). For example, when the ingot is polycrystallized during the growth of the ingot, the ingot is melted and grown again. At this time, the dopant is volatilized and can be supplied again.

Subsequently, a silicon single crystal ingot may be grown (S150). The growth of the silicon monocrystalline ingot will be described in detail as follows.

The seed is dipped in the silicon melt, and a part of the silicon melt is solidified, so that an elongated neck from the above-mentioned seed can be grown.

Subsequently, a shoulder can be grown continuously from the lower part of the neck, in which the shoulder grows vertically and vertically from the neck, so that the diameter of the ingot can also grow in the lateral direction (radial direction).

After the growth of the shoulder, the ingot may grow in the vertical direction during the growth process of the body.

As described above, the ingot can be slowly lifted upward in the ingot growth process including the growth of the neck, the shoulder, and the body from the dipping of the seed.

4 is a view showing a grown silicon single crystal ingot.

The silicon single crystal ingot grown by the above-described method may have a longitudinal resistance of 3 milliohms or less, and the longitudinal direction is the longitudinal direction in the body in Fig. The resistance variation of the silicon single crystal ingot may be 1.5 milliohms to 3 milliohms.

5 is a graph showing an increase in resistivity with decreasing dopant in a silicon melt.

It is shown that the resistivity of the silicon monocrystalline ingot increases with the decrease of the dopant in the silicon melt. This phenomenon may occur when the dopant is volatilized without the doping stabilization process.

FIG. 6 is a diagram showing a decrease in specific resistance due to addition of a doping stabilization process. FIG.

Resist (1) shows the resistivity of the silicon single crystal ingot manufactured by the conventional process in which the dopant stabilization process is omitted, and Res. (2) to Res. (4) Are the resistivities of one embodiment of the silicon single crystal ingot manufactured according to the single crystal growth method.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

10: chamber 20: heating section
31: side heat insulating portion 32: upper heat insulating portion
42: Seed cable 50: Support means
60: quartz crucible 65: graphite crucible
70: cooling pipe

Claims (9)

(A) preparing a silicon melt in a crucible;
(B) supplying a dopant to the silicon melt; And
(C) diffusing the dopant into the silicon melt and exhausting the dopant oxide around the silicon melt,
The height of the crucible in the step (c) is lower than the height of the crucible in the step (b)
Wherein the rotation speed of the crucible in the step (c) is 0.1 to 0.5 times the rotation speed of the crucible in the step (b). The method according to claim 1,
Wherein a magnetic field applied to the crucible in step (b) is turned off, and a magnetic field applied to the crucible in step (c) is turned on. delete The method according to claim 1,
The distance from the upper heat insulating portion to the surface of the silicon melt in the step (c) is preferably 20% to 40% larger than the distance from the upper heat insulating portion to the surface of the silicon melt in the step (b) . The method according to claim 1,
Wherein an inert gas is supplied between the upper heat insulating portion and the silicon melt in the step (c). 6. The method of claim 5,
Wherein the inert gas is supplied at 80 to 120 lpm. The method according to claim 1,
And further adding the dopant to the silicon melt after the step (c). 7. A silicon monocrystalline ingot produced by the method of any one of claims 1, 2, and 4 to 7, wherein the longitudinal resistance is 3 milliohms or less. 9. The method of claim 8,
A silicon monocrystalline ingot having a resistance deviation of 1.5 milliohms (ohm) to 3 milliohms.

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