KR101596550B1 - Apparutus and Method for Growing Ingot - Google Patents

Abstract

An ingot growing apparatus of the present invention is an apparatus for growing an ingot from a silicon melt contained in a quartz crucible using seed crystals, comprising: a chamber; A quartz crucible disposed within the chamber to receive the silicon melt; A heater unit for transmitting thermal energy to the quartz crucible; A lift cable for immersing the seed crystal in the silicon melt and rotating and pulling the seed crystal to grow an ingot; A heat shielding member disposed above the quartz crucible and having a hole through which the ingot to be grown passes, as a heat insulating means for shielding the heat of the silicon melt from the outside; And a neck cover mounted on the upper side of the heat shield to adjust a size of the hole; And a control unit.
The ingot growing apparatus of the present invention is advantageous in that it can stably produce a high-quality large diameter ingot.

Description

[0001] The present invention relates to an ingot growing apparatus and an ingot growing method,

The present invention relates to an ingot growing apparatus and an ingot growing method for producing a single crystal silicon ingot.

In general, a silicon single crystal ingot which is a material of a wafer is manufactured by the Czochralski method (CZ method).

The CZ method is a method in which silicon is put into a quartz crucible, the quartz crucible is heated to melt the silicon, the seed crystal is brought into contact with the silicon melt while being slowly pulled up while being rotated, And the ingot having a predetermined diameter is grown according to solidification.

However, when the seed crystal is deeply dipped in silicon, the temperature at the bottom of the seed crystal sharply rises to the surface temperature of the melt, and a thermal shock is applied to the bottom of the seed crystal.

As a result, shear stress is induced in the seed crystal, which causes dislocation at the melt contact site.

Therefore, in order to prevent the potential from propagating to the ingot, a dash necking process was performed during the initial ingot growth.

The deshrinking process is a technique of removing the dislocations by pulling the ingots slender and long. At this time, the diameter of the neck portion of the ingot to be grown in the necking process is about 3 to 5 mm.

At this time, when the diameter of the neck portion exceeds 5 mm, the propagation speed of the potential becomes larger than the growth rate of the ingot, while the magnitude of the shear stress caused by the temperature difference between the top and bottom of the neck portion and the inside / outside gradually increases, The dislocation generated at the lower end of the seed crystals may not be removed. Therefore, the diameter of the neck portion is reduced in the deshrinking step.

However, the desizing process has a positive effect of eliminating dislocations, but the seed crystals have a negative influence on supporting ingots of a high weight.

That is, since the neck portion of the ingot having a long length of the entire ingot is applied, if the neck portion can not withstand the load of the ingot, there is a possibility that the ingot falls into the melt due to breakage of the neck portion.

In particular, in the case of an ingot having a diameter of 450 mm, the ingot weighs 1 ton in the latter half of the process, and the 3-5 mm thin neck formed by the deshing process supports the weight of ingot reaching 1 ton. Can not.

Therefore, in recent years, techniques for growing large-diameter ingots without advancing the desizing process have been researched and developed.

On the other hand, in recent years, with the advancement of semiconductor technology, the ingot has been cured in order to improve the efficiency. Due to this, it is necessary to stack more polycrystalline silicon in the quartz crucible.

As a result, the heater power for heating the polycrystalline silicon increases, the cristobalite of the quartz crucible is promoted as well as the cost of the ingot increases with the increase of the heater power, and the yield of the ingot becomes worse .

To solve the above problems, the present invention is to provide an ingot growing apparatus and an ingot growing method which can reduce the heat loss in the production of ingots, increase the diameter of the neck portion, and increase the diameter of the neck portion. .

The ingot growing apparatus of this embodiment is an apparatus for growing an ingot from a silicon melt contained in a quartz crucible by using seed crystals, comprising: a chamber; A quartz crucible disposed within the chamber to receive the silicon melt; A heater unit for transmitting thermal energy to the quartz crucible; A lift cable for immersing the seed crystal in the silicon melt and rotating and pulling the seed crystal to grow an ingot; A heat shielding member disposed above the quartz crucible and having a hole through which the ingot to be grown passes, as a heat insulating means for shielding the heat of the silicon melt from the outside; And a neck cover mounted on the upper side of the heat shield to adjust a size of the hole; And a control unit.

The ingot growth method of this embodiment includes the steps of stacking polycrystalline silicon on a quartz crucible; Melting the polycrystalline silicon after minimizing the holes of the heat shield provided on the quartz crucible with a neck cover; Positioning the seed crystal between the silicon melt and the neck cover to dope the seed crystal into the melt of the molten silicon; A seed crystal is heated by the silicon melt and then the seed crystal is immersed in a silicon melt; and after completion of a necking step of forming a neck portion of the ingot by using the seed crystal, the diameter of the neck portion is increased Increasing the hole size of the heat shield according to the diameter expansion with the neck cover, while performing a shouldering process; Forming a hole of the heat shield with a predetermined size larger than the body by using the neck cover while performing a body glowing process of forming an ingot body using the seed crystal; And a control unit.

According to the present embodiment, the diameter of the hole of the heat shield can be adjusted to minimize the thermal shock generated when the seed crystals are immersed in the melt, and when forming the neck portion of the ingot, the upper and lower portions of the neck portion and the inner / By reducing the temperature difference, shear stress can be minimized.

And, due to the reduction of thermal shock, the dislocation generation rate of the neck portion can also be reduced, thereby allowing the diameter of the neck portion to grow.

The neck portion having the increased diameter can withstand the ingot load of a high weight, so that it is advantageous to stably produce a large-diameter ingot with a high weight.

In addition, according to the present embodiment, it is possible to improve the quality of the ingot by reducing the heater power when heating the silicon melt, and to lower the production cost.

According to this embodiment, there is an advantage that the quality of the ingot can be improved by controlling the temperature of the outer side of the ingot precisely to suppress the defect of the ingot.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an ingot growing apparatus equipped with a neck cover capable of adjusting the hole size of a heat shield, according to an embodiment of the present invention. FIG.
Figure 2 shows a schematic view of an ingot growing apparatus in which a neck cover reduces the hole size of a heat shield, according to an embodiment of the present invention.
3 is a perspective view showing a cross section of a heat shield and a neck cover according to an embodiment of the present invention.
FIG. 4 is a plan view showing a neck cover positioned on an upper surface of a heat shield according to an embodiment of the present invention; FIG.
5 is a plan view showing a part of the neck cover moved to the hole of the heat shield according to the embodiment of the present invention.
6 is a flowchart of an ingot growing method using an ingot growing apparatus equipped with a neck cover according to an embodiment of the present invention.

Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. It should be understood, however, that the scope of the inventive concept of the present embodiment can be determined from the matters disclosed in the present embodiment, and the spirit of the present invention possessed by the present embodiment is not limited to the implementation of addition, deletion, Variations.

1 shows a schematic view of an ingot growing apparatus provided with a neck cover 100 capable of adjusting the hole size of a heat shielding member according to an embodiment of the present invention.

1, the ingot growing apparatus according to the present embodiment includes a chamber 10, a quartz crucible 20 for receiving a silicon melt, a seed for raising an ingot in the silicon melt, A seed chuck 300 for fixing the seed crystal 300 and a lifting cable 310 for moving the seed crystal chuck 300 up and down to grow an ingot, a heater for heating the quartz crucible 20, And a side heat shielding portion 40 for shielding heat from the side of the heater portion.

In particular, the ingot growing apparatus of the present embodiment includes a heat shield 200 for shielding the heat of the silicon melt from the outside on the quartz crucible 20, a neck cover 200 for adjusting the hole size of the heat shield 200, (100) neck cover.

Hereinafter, the constituent elements of the ingot growing apparatus of the present embodiment will be described in more detail.

First, the chamber 10 provides a space in which predetermined processes for growing an ingot for a wafer used as an electronic component material such as a semiconductor are performed. That is, the constituent elements of the ingot growing apparatus are provided in the chamber 10 to perform a process for growing an ingot.

A quartz crucible 20 in which a silicon melt is accommodated as a hot zone structure is disposed in the chamber 10 and a support structure for supporting the load of the quartz crucible 20 and a supporting structure for supporting a load of the quartz crucible 20 Respectively. Such a pedestal is equipped with a rotation driving device so that the quartz crucible 20 can be rotated and lifted.

A heater unit 30 for supplying thermal energy is disposed on the outer side of the quartz crucible 20 to melt the polycrystalline silicon serving as a raw material of the ingot and the heater unit 30 and the heater unit 30 are disposed outside the heater unit 30. [ A side heat shielding portion 40 is provided for insulating the heat of the quartz crucible 20 from the outside of the chamber 10.

A seed crystal for growing the ingot from the molten silicon melt and a seed crystal chuck 300 for receiving the seed crystal are arranged on the quartz crucible 20 and the seed crystal chuck 300 is lifted and rotated A lifting cable 310 is connected to the upper portion of the seed crystal chuck 300.

When the polycrystalline silicon melts, the heat of the quartz crucible 20 may leak upward, and when the necking process for forming the neck portion of the ingot from the seed crystal proceeds, the temperature of the neck portion, There is a problem that a dislocation occurs due to the difference.

In order to prevent this, the ingot growing apparatus further includes a heat shield 200 for preventing heat from being emitted from the upper side of the quartz crucible 20 to the outside. The heat shield 200 is formed to surround the upper side of the quartz crucible 20 and have a hole through which the ingot to be grown can pass.

However, the shape of the heat shield 200 may be somewhat effective in preventing the heat of the silicon melt of the quartz crucible 20 from being discharged upward. However, There is a limit to precisely controlling the temperature difference between the top and bottom and the inside / outside of the neck portion having a small diameter in the necking process.

In order to overcome these limitations, the ingot growing apparatus of this embodiment further includes a neck cover 100 capable of adjusting the diameter of the hole of the heat shield 200 according to the progress of the process.

Figure 2 shows a schematic view of an ingot growing apparatus in which a neck cover reduces the hole size of a heat shield, according to an embodiment of the present invention.

Referring to FIG. 2, the neck cover 100 is mounted on the top surface of the heat shield 200 to reduce the diameter of the hole of the heat shield 200 during the necking process, thereby covering the neck of the thin diameter.

Due to such a constitution, the ingot growing apparatus of the present embodiment can insulate the top and bottom of the neck portion and the inside / outside of the neck portion with the neck cover 100 during the necking process, so that the potential generated in the neck portion can be suppressed.

Further, as the dislocation generation is suppressed, the diameter of the neck portion can be increased to 7 mm or more, and the neck portion of 7 mm or more can withstand the load of the ingot having a high weight of 450 mm or more.

Hereinafter, the structure of the heat shield 200 and the neck cover 100 will be described in more detail.

3 is a perspective view showing a cross section of a heat shield and a neck cover according to an embodiment of the present invention.

Referring to FIG. 3, the heat shield 200 of the present embodiment is formed in a ring shape surrounding the ingot to be grown, and the diameter of the hole gradually decreases from the upper portion to the lower portion.

The neck cover 100 includes an adjusting unit 130 mounted on an upper surface of the train body 200 to adjust the hole size of the heat shield 200 and a control unit 130, And a support unit 120 connecting the driving unit 110 and the control unit 130. The control unit 130 controls the amount of movement of the control unit 130 by moving the control unit 130 upward.

More specifically, the control unit 130 may be configured to have various shapes that cover the holes by moving to the holes of the heat shield 200 along the upper surface of the train body 200.

For example, when viewed from the side, the controller 130 may be configured to include an arc-shaped heat-insulating portion and rotate along an upper surface of the heat-shielding body 200 to cover the holes of the heat-shielding body 200 .

At this time, the heat insulating part is made of a material that has high reflectance, high temperature stability, and prevents contamination of the silicon melt, in order to block the heat of the silicon melt and insulate the neck part. For example, the insulating part may be composed of high-purity quartz, graphite or a high-purity carbon composite (M / I 1.0 ppma or less), and the surface may be coated with carbon having a high reflectance.

That is, when the driving unit 110 moves down the adjusting unit 130 via the supporting unit 120 connected to the upper end of the adjusting unit 130, the lower end of the adjusting unit 130 moves to the hole of the heating unit 200 , The size of the hole can be reduced.

Conversely, when the driving unit 110 pulls up the adjustment unit 130 through the support unit 120, the adjustment unit 130 moves to the upper surface of the heat shield 200, thereby increasing the size of the hole.

When the control part 130 is viewed from the front, it may be constituted by a fan-shaped heat insulating part whose edges are cut off. At this time, the center angle size of the heat insulating portion is preferably 180 degrees or less so that the controller 130 can smoothly move to the hole of the heat shield 200. In addition, since the central angle of the regulating portion 130 is less than 180 degrees, it is preferable that the heat insulating portion is provided in two or more so as to cover the perimeter of the hole.

For example, the control unit 130 may be configured such that three fan-shaped insulating units having a center angle of 120 degrees are spaced apart at intervals of 120 degrees and disposed on the upper surface of the train body.

Meanwhile, the driving unit 110 controls the amount of movement of the control unit 130 from the upper surface of the heat shield to the holes of the heat shield 200.

That is, according to the ingot growing process, the driving unit 110 can adjust the hole size of the heat shield 200 by adjusting the amount by which the adjusting unit 130 is moved alone.

For example, in the necking process, the hole size of the train body 200 is reduced by the diameter of the neck portion to insulate the neck portion from the outside, and when the body is grown, the size of the hole is increased by the diameter of the ingot body portion, So that the control portion 130 does not interfere with the ingot to be grown.

The driving unit 110 may be mounted outside the chamber, and the driving unit 110 and the adjusting unit 130 may be connected to each other by the supporting unit 120.

The upper end of the supporting part 120 may be connected to the driving part 110 and the lower end of the supporting part 120 may be connected to the adjusting part 130 to support the adjusting part 130.

When the support part 120 is formed of a wire, the driving part 110 can increase the length of the wire, move the adjustment part 130 to the hole by using the weight of the adjustment part 130, The adjusting unit 130 can be moved to the upper surface of the heat shield 200 by pulling the adjusting unit 130.

When the support part 120 is constituted by a support, the drive part 110 moves the support part upward to move the adjustment part 130 connected to the lower part to the upper surface of the train body 200, The control unit 130 can be moved to the hole of the heat shield 200. In this case,

However, when the adjusting unit 130 moves from the upper surface of the heat shield 200, cracks are generated due to the friction between the adjusting unit 130 and the heat shield 200, There is a problem that the size of the hole can not be precisely adjusted because the heat shield 130 is caught on the upper surface of the heat shield 200.

A rail 131 is provided on the bottom surface of the control part 130 and a groove 201 is formed on the top surface of the heat shield 200 so that the rail 131 of the control part 130 The above problem can be solved by fitting the regulating portion 130 and the heat shield 200 into the groove 201 of the heat shield 200.

That is, the controller 130 is configured to move according to the guide of the grooved groove 201 in the heat shield 200 so that the controller 130 can be prevented from deviating from the movement path, 131 and the grooves 201 are provided only in the adjustment part 130 and a part of the heat shield 200 to minimize the friction, thereby preventing the occurrence of cracks.

In addition, the rails 131 and the grooves 201 may be formed of a high-strength metal sheath such as molybdenum or tungsten to prevent cracks.

Alternatively, SiC coating may be applied to the portion where the regulator 130 and the heat shield 200 are rubbed to increase the strength, thereby preventing the generation of cracks.

Hereinafter, the operation of the neck cover 100 will be described with reference to FIGS. 4 and 5. FIG.

FIG. 4 is a plan view showing a state in which a neck cover 100 is placed on an upper surface of a heat shield according to an embodiment of the present invention, and FIG. 5 is a plan view showing a part of the neck cover 100, Fig.

4, all of the neck cover 100 is positioned on the upper surface of the heat shield 200, and the heat shield 200 has the largest hole size.

As described above, the size of the hole of the heat shield 200 is larger than the diameter of the ingot body portion. When the neck cover 100 is positioned as described above, the body shadowing process will be mainly performed. That is, the neck cover 100 may be entirely moved to the upper surface of the heat shield 200 so as not to interfere with ingot growth.

Referring to FIG. 5, a part of the neck cover 100 moves to the hole of the heat shield 200 to cover the hole, thereby reducing the size of the hole. At this time, the diameter of the hole reduced due to the neck cover 100 can be configured to be close to the diameter of the neck portion.

That is, when the neck cover 100 is positioned as described above, the neck cover 100 may be in the course of the necking process.

After the necking process, the driving unit 110 moves the adjusting unit 130 to the upper surface of the heat shield so that the ingot growth is not hampered during the shouldering process of expanding the diameter of the ingot, Can increase.

More specifically, a method of growing an ingot using the neck cover 100 will be described with reference to FIG.

6 is a flowchart of an ingot growing method using an ingot growing apparatus equipped with a neck cover 100 according to an embodiment of the present invention.

First, after polycrystalline silicon is deposited on the quartz crucible 20, the heater portion 30 supplies thermal energy for melting the polycrystalline silicon.

At this time, the driving unit 110 moves the regulating unit 130 to the hole of the heat shield 200 as much as possible to minimize the size of the hole, thereby preventing heat transferred to the polycrystalline silicon from being emitted upward. As a result, the heat loss required for melting the silicon can be reduced, and the crystallization of the polycrystalline silicon can be suppressed. (S101)

Then, for the deeping process, the seed crystal and the seed crystal chuck 300 are lowered by the lifting cable 310. If the holes of the heat shield 200 covered with the controller 130 are smaller than the seed crystal chuck 300, the driving unit 110 may be configured such that a part of the neck cover 100 is connected to the upper surface of the heat shield 200, To increase the size of the holes so that the seed crystal chuck 300 can pass through.

The seed crystal chuck 300 is allowed to pass through the open hole and then to be positioned in the space between the silicon melt and the regulating part 130. Thereafter, when the seed crystal is sufficiently heated by the heat transferred from the silicon melt, the seed crystal is further lowered and deep-dipped in the silicon melt.

When the seed crystals are immersed, the temperature of the seed crystals to be heated should be at least 1000 degrees, preferably at least 1200 degrees and then immersed. The lower the temperature difference between the seed crystal and the silicon melt is, the less thermal shock is generated in the neck portion and the potential generation due to the thermal shock can be prevented. (S102)

Then, a necking process to form the neck portion of the ingot is started. For forming the neck portion, the lifting cable 310 rotates and pulls up the immersed seed crystal chuck 300. At this time, the driving part 110 moves the adjusting part 130 to the upper surface of the train body 200 so that the hole of the heat shielding body is formed to be larger than the neck part.

That is, the adjuster 130 surrounds the outer circumferential surface of the neck portion to block the heat of the neck portion from the outside, thereby reducing the temperature difference between the top and bottom and the inside / outside of the neck portion.

As the temperature difference between the top and bottom of the neck portion and the inside / outside temperature decreases, the magnitude of the shearing stress decreases and the propagation speed of the potential generated at the neck portion can be reduced.

As a result, the diameter of the neck portion can be improved by reducing the dislocation propagation speed, and the load of the ingot which can withstand the neck portion can be increased, so that it is possible to stably produce ingots of high weight and large diameter. (S103)

After the necking process is completed, a shouldering process is performed in which the neck portion is grown in the radial direction to improve the target diameter. At this time, the driving unit 110 gradually increases the hole size of the train body 200 in accordance with the increase of the diameter of the shoulder portion of the ingot.

In order to explain advantages of another aspect of the present embodiment, a method of controlling the temperature gradient (G) of the ingot to suppress occurrence of defects in the ingot will be described.

During the ingot growth, vacancy-type and interstitial-type point defects occur as the silicon melt is solidified, and then the ingot is continuously raised, As the portion was cooled, the vacancy point defects and the interstitial point defects merge to form aggregates, forming vacancy defects and interstitial defects.

The above defect is mainly used to control the ratio V / G of the pulling rate V of the single crystal and the temperature gradient G at the solid-liquid interface within a specific range. When the hole size of the upper heat shield 200 is adjusted, G can be precisely controlled, and the occurrence of the defects can be suppressed.

That is, the neck cover 100 can suppress the occurrence of defects in the ingot by controlling the temperature gradient G by adjusting the hole size of the heat shield 200. (S104)

Thereafter, a body growing process for forming the body portion of the ingot proceeds, and the diameter of the neck portion is improved to withstand a high weight, so that the body of a large diameter can be grown.

At this time, the driving unit 110 can precisely control the temperature gradient (G) of the body of the ingot by disposing the adjusting unit 130 near the diameter of the body.

Further, there is also an advantage that the cooling rate of the ingot on the upper side of the heat shield 200 can be increased by blocking the leakage of the heat of the silicon melt to the outside. (S105)

Finally, a high-quality ingot of a large diameter is produced by a tailing process of forming the tail portion of the ingot. (S106)

By the above-described ingot growing apparatus and method, it is possible to reduce heat loss by intercepting the heat flowing out of the silicon melt when heating the silicon melt, and by reducing the thermal shock by heating the seed crystal before the necking process, And it is possible to grow the ingot with a larger diameter from the improvement of the diameter of the neck portion.

Further, since the upper side heat shield 200 can precisely adjust the temperature of the outer side of the ingot, it has an advantage that a high-quality ingot can be produced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

10: chamber
20: Quartz crucible
30:
40: side rail portion
100: Neck cover
200: heat shield
300: seed crystal chuck

Claims (11)

An apparatus for growing an ingot from a silicon melt contained in a quartz crucible by using seed crystals,
chamber;
A quartz crucible disposed within the chamber to receive the silicon melt;
A heater unit for transmitting thermal energy to the quartz crucible;
A lift cable for immersing the seed crystal in the silicon melt and rotating and pulling the seed crystal to grow the ingot;
A heat shielding member disposed above the quartz crucible and having a hole through which the ingot to be grown passes, as a heat insulating means for shielding the heat of the silicon melt from the outside; And
A neck cover mounted on the upper side of the heat shield to adjust a size of the hole; Lt; / RTI >
The neck cover
And an adjusting unit disposed on an upper surface of the heat shield and moving between the upper surface of the heat shield and the hole,
Wherein the adjusting portion is disposed in such a manner that three or more fan-shaped heat insulating portions are spaced apart from each other on the upper surface of the heat shield by a predetermined angle. delete The method according to claim 1,
And the neck cover is connected to the adjuster to control movement of the adjuster. The method of claim 3,
Wherein the neck cover includes a support portion connected to the driving portion at its upper portion and connected to the adjustment portion at a lower portion thereof to support the adjustment portion. delete The method according to claim 1,
Wherein the adjusting portion is composed of three heat insulating portions, and the heat insulating portion is disposed apart from the upper surface of the heat shield by 120 degrees. The method according to claim 1,
Wherein the rail is provided on a lower portion of the heat insulating portion, and a groove is provided on an upper surface of the heat shield, and the rail and the groove are coupled. The method according to claim 1,
Wherein the regulating portion is composed of high purity quartz, graphite or a high purity carbon composite, and the surface of the regulating portion is coated with pyrolytic graphite. 5. The method of claim 4,
Wherein the support portion comprises a wire or a support. Stacking polycrystalline silicon on the quartz crucible;
Melting the polycrystalline silicon after minimizing the holes of the heat shield provided on the quartz crucible with a neck cover;
Positioning the seed crystal between the silicon melt and the neck cover to dope the seed crystal into the melt of the molten silicon;
Immersing the seed crystal in a silicon melt after the seed crystal is heated by the silicon melt;
After completing the necking step of forming the neck portion of the ingot by using the seed crystal, a hole size of the heat shielding material is increased in accordance with the diameter expansion with the neck cover, while performing a shouldering process of expanding the diameter of the neck portion ;
Forming a hole of the heat shield with a predetermined size larger than the body by using the neck cover while performing a body glowing process of forming an ingot body using the seed crystal; ≪ / RTI > 11. The method of claim 10,
Wherein in the necking step, the neck cover has a hole size larger than the neck portion by a predetermined size.

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