WO2016064013A1

WO2016064013A1 - Residual melt removing method

Info

Publication number: WO2016064013A1
Application number: PCT/KR2014/010203
Authority: WO
Inventors: 백성선; 김광훈; 이상준; 김재민; 유학도; 왕종회
Original assignee: 웅진에너지 주식회사
Priority date: 2014-10-23
Filing date: 2014-10-28
Publication date: 2016-04-28
Also published as: KR20160047935A; KR101635946B1

Abstract

A residual melt removing method is provided. The residual melt removing method is a method for removing a residual melt, which exists in a quartz crucible, after monocrystalline ingot growth by the Czochralski method, the method comprising the steps of: (a) raising the temperature of a heater to a first temperature, thereby maintaining the residual melt, which exists in the quartz crucible, in a liquid state; (b) dipping a seed into the residual melt; (c) controlling the temperature of the heater within a second temperature range, thereby crystallizing the residual melt; (d) raising the temperature of the heater to a third temperature, thereby separating crystals from the quartz crucible; and (e) lifting the seed, which is connected to the crystals, at a predetermined ascending rate, thereby removing the crystals.

Description

How to remove residual melt

The present invention relates to a method for removing residual melt after single crystal ingot growth by Czochralski method.

Generally, single crystal ingots are prepared by Czochralski crystal growth method (CZ method). More specifically, the crucible installed in the hot zone region is filled with a solid raw material such as polysilicon, heated and melted with an electrothermal heater to form a melt, and then a single crystal seed is suspended in the seed connector to contact the melt. Rotate and raise slowly. The seed connector is then pulled up in the order of a neck part, a shoulder part with increasing diameter, and a body part having a cylindrical shape with a constant diameter, and finally a tail with decreasing diameter. A single crystal ingot ending part) is obtained.

In addition, the multi-growth Czochralski method (MP-CZ), which produces a plurality of ingots in the Czochralski method several times in one quartz crucible, has a smaller cost than the conventional Czochralski method. It is able to produce and is attracting new attention.

However, in the conventional Czochralski method, after the single crystal ingot growth, some of the melt remains in the quartz crucible, and this residual melt usually contains a large amount of impurities, thereby degrading the quality of the single crystal ingot.

One embodiment of the present invention is to provide a residual melt removal method that can prevent the degradation of the single crystal ingot by effectively removing the residual melt inside the quartz crucible after the single crystal ingot growth by Czochralski method.

According to an aspect of the present invention, in the method of removing residual melt present in a quartz crucible after single crystal ingot growth by Czochralski method, (a) the residual melt present in the quartz crucible by raising the temperature of the heater to a first temperature Maintaining the liquid phase, (b) dipping the seed in the residual melt, (c) controlling the temperature of the heater within a second temperature range to crystallize the residual melt, (d) the temperature of the heater Providing a third melt temperature to separate the crystals from the quartz crucible and (e) pulling the seed associated with the crystals at a predetermined rate of rise to remove the crystals. do.

In this case, the step (e) may include the step of (e-1) cooling the crystal by a shielding member positioned on the interface of the residual melt and the hollow portion formed therein.

In this case, in the step (a), the first temperature may be 1500 degrees or more and 1600 degrees or less.

In this case, in the step (c), the second temperature range may be 30% or more and 60% or less of the first temperature.

In this case, step (c) may include (c-1) dipping the seed in the residual melt so that the temperature of the heater is 30% of the first temperature.

In this case, the step (c) may include the step (c-2) to make the temperature of the heater to 60% of the first temperature when 50% of the residual melt is crystallized.

In this case, in the step (d), the third temperature may be higher than the first temperature.

In this case, step (d) may include the step of (d-1) the temperature of the heater to the third temperature when the residual melt is crystallized 80%.

At this time, the rising speed in the step (e) may be less than 10mm / min 60mm / min.

At this time, in the step (e-1), the distance between the lower surface of the shield member and the interface of the residual melt may be 100mm or more and 150mm or less.

At this time, if the residual melt present in the quartz crucible after step (e) exceeds 100g it can be repeated to step (a) to (e).

Residual melt removal method after the single crystal ingot growth by the Czochralski method according to an embodiment of the present invention to prevent the degradation of the quality of the single crystal ingot by effectively removing the residual melt by controlling the rate of rise of the seed and the reduction of the heater power. Can be.

1 is a flow chart illustrating a residual melt removal method according to an embodiment of the present invention.

2 is a cross-sectional view of a side view of an ingot growth apparatus that may be used to implement a method of removing residual melt in accordance with one embodiment of the present invention.

3 is a cross-sectional view of a portion of an ingot growth apparatus that may be used to implement a method for removing residual melt according to an embodiment of the present invention.

4 is a cross-sectional view showing an initial state for performing the residual melt removal method according to an embodiment of the present invention.

Figure 5 is a schematic diagram showing the first removal of the residual melt by performing the residual melt removal method according to an embodiment of the present invention.

6 is a schematic view showing a second removal of the residual melt by performing the residual melt removal method according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof. In addition, when a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only when the other part is "right on" but also another part in the middle. Conversely, when a part such as a layer, film, region, plate, etc. is "below" another part, this includes not only the other part "below" but also another part in the middle.

Hereinafter, a residual melt removing method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart illustrating a residual melt removal method according to an embodiment of the present invention. 2 is a cross-sectional view of a side view of an ingot growth apparatus that may be used to implement a method of removing residual melt in accordance with one embodiment of the present invention. 3 is a cross-sectional view of a portion of an ingot growth apparatus that may be used to implement a method of removing residual melt in accordance with one embodiment of the present invention.

Referring to Figure 1, the residual melt removal method according to an embodiment of the present invention is to continuously produce a single crystal ingot growth by the Czochralski method and to remove the residual melt present in the quartz crucible after separating the grown single crystal ingot It is possible to improve the quality of single crystal ingots. This is because the residual melt usually contains many impurities.

1 to 3, a single crystal ingot 43 is grown by an ingot growth apparatus 10 that can be used to perform the residual melt removal method according to an embodiment of the present invention.

Therefore, the ingot growth apparatus 10 for growing the single crystal ingot 43 by the Czochralski method will be described below before explaining the method of removing the residual melt according to the exemplary embodiment of the present invention.

Referring to FIG. 2, the ingot growth apparatus 10 may include a base 20, a main chamber 30, a dome chamber 90, a full chamber 70, and a driver 50. On the other hand, the base 20 may be installed on the bottom surface on which the ingot growth apparatus is placed and has a form in which a plurality of frames are combined to support the ingot growth apparatus 10.

In this case, the main chamber support 33 may be installed on the base 20, and the main chamber 30 may be installed on the main chamber support 33. 2 and 3, the main chamber 30 may be formed in a cylindrical shape, but is not limited thereto.

Referring to FIG. 3, the main chamber 30 has a crucible 35 capable of accommodating a raw material, for example, polysilicon, and a heater 31 for melting the raw material by heating the crucible on the outer surface of the crucible. Can be installed.

At this time, the crucible 35 may include a quartz crucible 35a capable of melting polysilicon to accommodate the silicon melt 39 and a graphite crucible 35b surrounding the outer circumferential surface of the quartz crucible to support the quartz crucible.

On the other hand, the heater 31 is located on the outer surface of the graphite crucible 35b to supply thermal energy necessary for growth of the single crystal ingot 43 as radiant heat.

2 and 3, the dome chamber 90 is installed on the top of the crucible 35, the lower portion of the dome chamber may be made of a dome shape and the upper portion may be formed in a cylindrical shape. Inside the dome chamber 90, a cooling device (not shown) for cooling the ingot 43 growing in the crucible 35 may be installed. The cooling device may be formed to circulate the cooling water therein.

Referring to FIG. 2, the full chamber 70 may be installed above the dome chamber 90, and the full chamber may have a tubular shape extending upward. Referring to FIG. 3, the full chamber 70 passes through the full chamber while the growing ingot 43 rises along the seed cable 57. That is, the full chamber 70 serves as a passage through which the ingot can pass.

At this time, the door 71 is installed on the circumferential surface of the full chamber 70 to check the growth of the ingot 43 or to clean the inside of the full chamber 70 when the ingot 43 is separated in the finished state. It can be used for the purpose.

2 and 3, the driving unit 50 is installed above the full chamber 70, and includes a housing 51, a supporting roller 55, a drum 53, a driving motor 59, and a seed cable ( 57).

At this time, the driving unit 50 moves the seed cable 57 supported by the support roller 55 in the vertical direction to draw out the ingot 43 to the outside of the crucible 35. The housing 51 is cylindrical and installed on the upper portion of the full chamber 70, and the inside of the housing 51 may be maintained in a vacuum state.

Meanwhile, the support roller 55 may be installed inside the housing 51 to support the seed cable 57, and a lifting hole 52 may be formed under the support roller 55 to allow the seed cable to rise and fall. . The seed cable 57 is rotated and hung in the outer circumferential groove of the support roller 55, and wound around the surface of the drum 53 to descend to the upper portion of the silicon melt 39 through the lifting hole 52.

Referring to FIG. 3, a seed 61 and a seed chuck (not shown) may be installed at an end portion of the seed cable 57 so as to raise the growing ingot 43. At this time, when the drum 53 rotates by the drive motor 59, the seed cable 57 is wound around the drum, and the growing ingot 43 rises while rotating slowly.

As illustrated in FIG. 3, a cylindrical shielding member 37 having a hollow portion formed therein may be installed at an upper portion of the interface of the silicon melt 39, but the shape of the shielding member is not limited thereto. The shield member 37 blocks heat emitted from the silicon melt 39 for cooling the grown silicon ingot 43.

On the other hand, when the growth of the single crystal ingot 43 is completed, the single crystal ingot is separated from the ingot growth apparatus 10. At this time, the residual melt 39 remains inside the quartz crucible 35a.

Residual melt removal method according to an embodiment of the present invention is effective to remove the residual melt (39) remaining in the quartz crucible (35a) after the single crystal ingot growth by Czochralski method by adjusting the rate of rise of the seed and the power of the heater. This improves the quality of the single crystal ingot 43.

To this end, the residual melt removing method according to an embodiment of the present invention to increase the temperature of the heater to the first temperature to maintain the residual melt present in the quartz crucible in the liquid phase (S10), dipping the seed in the residual melt Step S20, controlling the temperature of the heater within the second temperature range to crystallize the residual melt (S30), raising the temperature of the heater to a third temperature to separate the crystal from the quartz crucible (S40), and It may include the step (S50) to remove the crystals by pulling the connected seeds at a predetermined rate.

Referring to Figure 1, in step (S10) of maintaining the residual melt present in the quartz crucible by raising the temperature of the heater according to an embodiment of the present invention to the first temperature in the liquid phase temperature of the heater by controlling the power of the heater The first temperature, that is, 1500 to 1600 or less so that the residual melt 39 is maintained in the liquid phase so that the residual melt does not cool.

Meanwhile, in the step S20 of dipping the seed into the residual melt, the seed 61 is mounted on the seed cable 57 of the ingot growth apparatus 10, and the seed is lowered to contact the seed with the residual melt 39.

In the residual melt removing method according to an embodiment of the present invention, in the step (S30) of controlling the temperature of the heater within the second temperature range to crystallize the residual melt, first, the temperature of the heater 31 is adjusted by adjusting the heater power. When the temperature is lowered to 30% of the first temperature, and the seeds 61 are dipped in the residual melt 39, the seed crystallizes gradually from the contacting melt portion.

As such, the crystallization of the melt 39 gradually propagates from the top to the bottom of the residual melt and from the center to the outside over time, and after a certain time, the entire remaining melt turns into a crystal, so that the upper and lower temperature gradients of the crystal are natural. .

Thereafter, when 50% of the residual melt 39 is crystallized, that is, when 50% of the initial volume of the residual melt existing in the quartz crucible is crystallized, the temperature of the heater 31 is raised to 60% of the first temperature. Heat energy is transferred from the quartz crucible 35a. At this time, the remaining melt 39 existing inside the quartz crucible is still crystallized.

At this time, in the residual melt removal method according to an embodiment of the present invention, 50% of the residual melt may be 50% of the initial volume, but is not limited thereto.

At this time, since the temperature of the heater is raised to 60% of the first temperature to heat the quartz crucible 35a first, when the temperature of the heater is subsequently heated to the third temperature higher than the first temperature, the quartz crucible 35a is heated. Since the temperature of the quartz crucible is increased, the residual melt removing method according to an embodiment of the present invention can shorten the time required.

Meanwhile, in the residual melt removing method according to an embodiment of the present invention, in the step (S30) of crystallizing the residual melt by controlling the heater within the second temperature range, the residual melt is cooled to the second temperature, at which time, the second temperature May be greater than or equal to 30% and less than or equal to 60% of the first temperature, for example, less than or equal to 1400 degrees.

At this time, the residual melt 39 is drawn out to the outside from the quartz crucible 35a and is set to a condition such that an up-down temperature gradient that can solidify in the residual melt can be naturally formed.

However, the first temperature and the second temperature of the heater are not limited thereto and may be changed according to the diameter (not shown) of the quartz crucible 35a, the amount and temperature of the residual melt, and the like.

In the method of removing residual melt according to an embodiment of the present invention, in the step (S40) of separating the crystal from the quartz crucible by raising the temperature of the heater to a third temperature, the crystal may be smoothly separated from the quartz crucible 35a. When 80% of the residual melt 39 is crystallized, that is, when 80% of the initial volume of the residual melt existing in the quartz crucible is removed, the power of the heater is adjusted to raise the temperature of the heater to heat the quartz crucible.

At this time, in the residual melt removal method according to an embodiment of the present invention, 80% of the residual melt may be 80% of the initial volume, but is not limited thereto.

On the other hand, the temperature of the heater rises higher than the third temperature, that is, the first temperature, so that the crystal can be smoothly separated from the quartz crucible. At this time, the third temperature is a temperature, for example, 1600 degrees or more, which can be obtained by increasing the power of the heater in a normal melting process.

At this time, since the crystal passes through the hollow portion (not shown) formed inside the shielding member, the crystal size is smaller than the size of the hollow portion inside the shielding member, ie, when 80% of the residual melt 39 is crystallized. If it is raised, it may not be interfered with by the shielding member.

Residual melt removal method according to an embodiment of the present invention when the diameter of the hollow portion of the shield member is 250mm diameter of the crystal is 200mm may be 50mm difference, but is not limited to this.

In the method of removing the residual melt according to an embodiment of the present invention, in the step of removing the crystal by pulling the seed connected to the crystal at a predetermined rising rate (S50), the seed 61 is raised at a predetermined rising rate, that is, for example, The crystals are removed by pulling them to 10mm / min or more and 60mm / min or less. As such, when the rising speed of the seed 61 is raised at a low speed, the crystal 41 does not fall from the seed, thereby removing as much residual melt 39 as possible.

On the other hand, the predetermined ascent rate is set to a condition such that the residual melt 39 is withdrawn from the quartz crucible 35a so that an up-down temperature gradient that can solidify in the residual melt can be naturally formed.

However, the ascending speed is not limited thereto and may be changed depending on the diameter of the quartz crucible 35a, the amount and temperature of the remaining melt, and the like.

Residual melt removal method according to an embodiment of the present invention may include the step of cooling the crystals by the shielding member located on the interface of the residual melt and the hollow formed therein.

At this time, the shielding member is located above the interface of the residual melt, for example, the distance between the interface of the residual melt and the shielding member may be 100 mm or more and 150 mm or less, and a hollow part may be formed therein.

On the other hand, in the step of cooling the crystal by a shielding member positioned above the interface of the residual melt and having a hollow portion therein, the shielding member 37 remains in the quartz crucible 35a so that the crystal 41 does not melt. To block the heat released from

4 is a cross-sectional view showing an initial state for performing the residual melt removal method according to an embodiment of the present invention. Figure 5 is a schematic diagram showing the first removal of the residual melt by performing the residual melt removal method according to an embodiment of the present invention. 6 is a schematic view showing a second removal of the residual melt by performing the residual melt removal method according to an embodiment of the present invention.

Referring to Figures 4 and 5, once performed through the residual melt removal method according to an embodiment of the present invention can remove about 40 to 50% of the initial volume of the residual melt present in the quartz crucible.

At this time, in the residual melt removal method according to an embodiment of the present invention, 40 to 50% of the residual melt may be 40 to 50% of the initial volume, but is not limited thereto.

Referring to FIG. 6, therefore, in the residual melt removing method according to an embodiment of the present invention, the residual melt present in the quartz crucible is repeatedly performed when the residual melt present in the quartz crucible exceeds 100 g (S60). The temperature of the heater is raised to a first temperature until the temperature is 100 g or less, thereby maintaining the residual melt in the quartz crucible in a liquid phase (S10), dipping the seed in the residual melt (S20), and heating the temperature of the heater. Controlling within the second temperature range to crystallize the residual melt (S30), raising the temperature of the heater to a third temperature to separate the crystals from the quartz crucible (S40) and pulling the seeds connected to the crystals at a predetermined rate of rise; It may be carried out by repeating the step (S50) to remove the crystals.

In the step (S60), if the residual melt present in the quartz crucible exceeds 100 g, the residual melt is removed until the residual melt reaches 100 g or less, and a plurality of ingots of the Czochralski method are produced in one quartz crucible. When the ingot is produced by the multi-growth Czochralski method (MP-CZ), the quality of the single crystal ingot can be improved.

That is, if the residual melt present in the quartz crucible is less than 100g, when the single crystal ingot is produced, impurities contained in the residual melt will be small and will not affect the quality of the single crystal ingot.

Residual melt removal method according to an embodiment of the present invention can prevent the degradation of the single crystal ingot by effectively removing the residual melt from the quartz crucible.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention, within the scope of the same idea, the addition of components Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also be within the scope of the present invention.

Claims

In the residual melt removal method which exists in a quartz crucible after single crystal ingot growth by Czochralski method,

(a) raising the temperature of the heater to a first temperature to maintain the residual melt in the quartz crucible in the liquid phase;

(b) dipping a seed in the residual melt;

(c) controlling the temperature of the heater within a second temperature range to crystallize the residual melt;

(d) raising the temperature of the heater to a third temperature to separate the crystals from the quartz crucible; and

(e) lifting the seed associated with the crystal at a predetermined rate of ascension to remove the crystal.
According to claim 1,

Step (e) is

(e-1) cooling the crystals by a shielding member positioned above the interface of the residual melt and having a hollow portion formed therein.
According to claim 1,

Residual melt removal method in the step (a) the first temperature is 1500 degrees or more and 1600 degrees or less.
According to claim 1,

And wherein said second temperature range in step (c) is at least 30% and at most 60% of said first temperature.
The method of claim 4, wherein

Step (c) is

(c-1) dipping the residual melt and seeding the heater so that the temperature of the heater is 30% of the first temperature.
The method of claim 5,

Step (c) is

(c-2) causing the temperature of the heater to be 60% of the first temperature when 50% of the residual melt is crystallized.
According to claim 1,

And the third temperature in step (d) is higher than the first temperature.
According to claim 1,

Step (d)

(d-1) Residual melt removal method comprising the step of bringing the temperature of the heater to the third temperature when the residual melt is crystallized 80%.
According to claim 1,

Residual melt removal method in the step (e) the ascending speed is more than 10mm / min 60mm / min.
According to claim 1,

Residual melt removal method in the step (e) the ascending speed is more than 10mm / min 60mm / min.
According to claim 1,

After the step (e), if the residual melt present in the quartz crucible exceeds 100 g, the steps of (a) to (e) are repeated.