KR101759002B1 - Single crystal ingot growing apparatus - Google Patents

Abstract

The present invention relates to a monocrystalline ingot growing apparatus capable of repeatedly confirming the position of a silicon melt interface during single crystal ingot growth and thereby controlling the melt gap accurately.
The present invention provides a process for producing a single crystal ingot, comprising: a chamber for providing a closed space for growing a single crystal ingot; A crucible provided in the chamber to melt polycrystalline silicon to form a silicon melt; A crucible elevating portion for elevating the crucible; A heater provided around the crucible for heating the crucible; A heat shield member (nop) for maintaining the melt gap with the silicon melt interface and cooling the single crystal ingot; A temperature sensor for measuring the inner circumferential surface temperature of the crucible; A sensor elevating part for elevating the temperature sensor at a set time interval; And detecting a position change (AB = C) measured at a reference temperature set as the temperature sensor is lifted during the growth of the single crystal ingot, raising the crucible according to the position change (C) to keep the melt gap constant A single crystal ingot growing apparatus including the control unit.

Description

[0001] The present invention relates to a single crystal ingot growing apparatus,

The present invention relates to a monocrystalline ingot growing apparatus capable of repeatedly confirming the position of a silicon melt interface during single crystal ingot growth and thereby controlling the melt gap accurately.

Generally, in the single crystal ingot growing apparatus according to the Czochralski method, polycrystalline silicon is loaded in the crucible, and the polycrystalline silicon contained in the crucible is melted by the heat radiated from the heater to form a silicon melt , The seed is gradually rotated while being immersed in the silicon melt, and simultaneously raised.

Therefore, the silicon melt is crystallized around the seed, and the single crystal ingot is grown from the surface of the silicon melt.

Of course, the temperature at the position where the single crystal ingot is grown is equipped with a heat shielding member for shielding the heat of the heater on the upper side of the silicon melt interface in order to maintain the melting point or lower of the silicon melt.

At this time, the gap between the silicon melt interface and the heat shield member is set as the melt gap. In order to improve the quality of the single crystal ingot, it is necessary to maintain the melt gap at an appropriate distance during the process.

However, it is difficult to keep the melt gap at a proper distance because the heat shielding member is fixed while the silicon melt interface is reduced as the process proceeds.

Japanese Unexamined Patent Publication No. 2006-149890 discloses an apparatus capable of accurately detecting the melt surface position during the growth of a silicon single crystal. The molten ingot is re-melted to calculate the volume of the ingot, .

However, according to the prior art, the process time may be increased by 10 hours or more as the process of melting is repeated for each process, and a safety accident that the crucible is bent as heat is applied to the crucible for a long time may occur, There is a problem of deteriorating the quality of the ingot.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a single crystal ingot growing apparatus capable of repeatedly confirming the position of a silicon melt interface during single crystal ingot growth, .

The present invention provides a process for producing a single crystal ingot, comprising: a chamber for providing a closed space for growing a single crystal ingot; A crucible provided in the chamber to melt polycrystalline silicon to form a silicon melt; A crucible elevating portion for elevating the crucible; A heater provided around the crucible for heating the crucible; A heat shield member (nop) for maintaining the melt gap with the silicon melt interface and cooling the single crystal ingot; A temperature sensor for measuring the inner circumferential surface temperature of the crucible; A sensor elevating part for elevating the temperature sensor at a set time interval; And detecting a position change (AB = C) measured at a reference temperature set as the temperature sensor is lifted during the growth of the single crystal ingot, raising the crucible according to the position change (C) to keep the melt gap constant A single crystal ingot growing apparatus including the control unit.

The single crystal ingot growing apparatus according to the present invention detects a change in the internal side position C of the crucible measured at a reference temperature as the temperature sensor is raised and lowered when the sensor elevation portion is operated at a set time interval in the single crystal ingot growing step, The melt gap can be kept constant by raising the crucible in accordance with step (C).

Therefore, by precisely measuring the position of the silicon melt interface during the course of the single crystal ingot growing step and controlling the rise of the crucible accordingly to keep the melt gap constant, safety time is increased or the crucible is warped in advance There is an advantage that the quality of the single crystal ingot can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an example of a single crystal ingot growing apparatus of the present invention. Fig.
Fig. 2 is a view showing the melt gap and the temperature measurement position of the crucible in Fig. 1; Fig.
3 is a graph showing the temperature change of the crucible along the height of the crucible during single crystal ingot growth of the present invention.
4 is a flowchart showing an example of a single crystal ingot growing method 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 embodiments in which addition, Variations.

FIG. 1 is a view showing an example of a single crystal ingot growing apparatus of the present invention, and FIG. 2 is a view showing a melt gap and a temperature measurement position of the crucible in FIG.

1 and 2, the single crystal ingot growing apparatus of the present invention includes a chamber 110, a crucible 120 and a crucible elevating portion 125, a heater 130, a heat insulating material 140, A cooling member 160, a temperature sensor 170 and a sensor elevating unit 175, and a control unit 180. The control unit 180 controls the opening /

The chamber 110 is a closed space for forming a hot zone for growing an ingot from a silicon melt. The crucible 120, the heater 130, and the heat insulating material 140 are embedded in the chamber 110.

At least one transparent window 115 is provided on one side of the upper portion of the chamber 110 and the process inside the chamber 110 can be observed through the transparent window 115.

Of course, the optical pyrometer is provided outside the transparent window 115 to measure the diameter of the single crystal ingot through the transparent window 115 or to measure the temperature of the silicon melt.

In the present invention, the conventional optical pyrometer is configured by the temperature sensor 170 to measure the inner circumferential surface temperature of the crucible 120, which will be described in detail below.

The crucible 120 is a container containing a silicon melt, and the polycrystalline silicon is melted to form a silicon melt. In the embodiment, the crucible 120 is composed of an inner peripheral portion made of quartz and an outer peripheral portion made of graphite.

The crucible driving unit 125 is provided below the crucible 120 and may include a drive shaft and a pedestal so that the crucible 120 can be rotated and lifted during a single crystal ingot growing process .

In the embodiment, the crucible driving unit 125 is configured to raise the crucible 120 by 1 mm at intervals of 10 minutes in order to keep the melt gap G constant as the silicon melt is reduced as the single crystal ingot growing process proceeds , But is not limited to.

The heater 130 is a heat source for heating the crucible 120 and is provided around the crucible 120.

The heat insulating material 140 is provided on the inner circumferential surface of the chamber 110 so as to surround the heater 130 to prevent the heat of the heater 130 from escaping through the side surface of the chamber 110.

The upper end of the heating end member 150 is fixed on the upper side of the heat insulating member 140 and the lower end of the heat insulating member 140 is made of silicone contained in the crucible 120. [ And is maintained to maintain the melt interface (G) with the melt interface.

The cooling tube 160 is formed in a cylindrical case with a tube through which the cooling water flows. The cooling tip 160 has an inner upper end of the chamber 110 to allow the single crystal ingot passing through the heat end member 150 to pass therethrough. Respectively.

Accordingly, the single crystal ingot grown from the silicon melt is cooled while sequentially passing through the heat block member 150 and the cooling pipe 160.

The temperature sensor 170 may be an optical pyrometer measuring the inner circumferential surface temperature of the crucible 120 through the transparent window. An optical pyrometer may be used to measure the temperature of the silicon melt interface. A hole may be formed in the cooling pipe 160 which can obscure the visual field.

The sensor elevating unit 175 is configured to move the temperature sensor 170 in a vertical direction at a set time interval during the single crystal ingot growing process, and the temperature sensor 170 is moved up and down within a predetermined range.

In the embodiment, the sensor lifting unit 175 lifts the temperature sensor 170 within a predetermined range at intervals of 10 minutes while a process of growing a neck, a shoulder, and a body is progressed, .

Considering that 150 kg of polycrystalline silicon is melted and made into a silicon melt, the sensor elevating portion 175 is disposed at a position corresponding to the temperature sensor (not shown), considering that the initial silicon melt interface is formed at a height of 298 mm to 302 mm inside the crucible 120 The temperature sensor 170 is moved up and down within the range of the lower limit value of 298 mm and the upper limit value of 302 mm, which is the inner circumferential surface position of the crucible 120,

The control unit 180 controls the operation of the crucible elevating unit 125 and the sensor elevating unit 175. The control unit 180 sets the inner circumferential surface positions A and B of the crucible 120 corresponding to the reference temperature during the single crystal ingot growing process And the crucible 120 is controlled to rise in consideration of the fluctuation (AB = C) of the position of the inner circumferential surface of the crucible 120 corresponding to the reference temperature.

In an embodiment, the control unit 180 can set the reference temperature to 1428 ° C to 1430 ° C, which is the temperature of the silicon melt interface, and is not limited.

The controller 180 checks the inner circumferential surface points A and B of the crucible 120 measured at 1428 ° C by the temperature sensor 160 every 10 minutes in the single crystal ingot growing process, The crucible 120 is ascended by controlling the operation of the crucible lifting unit 175 in consideration of the positional change C after confirming the measured position change (AB = C).

Of course, the crucible lifting unit 175 raises the crucible 120 according to an automatically set program at a set time interval, or if the automatic program is not separately set, the operation of the crucible lifting unit 175 is controlled by the control unit 180 .

3 is a graph showing the temperature change of the crucible according to the height of the crucible during single crystal ingot growth of the present invention.

When 150 kg of polycrystalline silicon is melted as shown in FIG. 3 before proceeding with the single crystal ingot growing step of the present invention, the height of the silicon melt interface measured at 1430 ° C is 300 mm on the inner peripheral surface of the crucible.

However, as the seed is slowly rotated in the state of being contained in the silicon melt, the single crystal ingot is grown and the height of the silicon melt interface is lowered. The height of the silicon melt interface measured at 1430 ° C is 220 mm on the inner peripheral surface of the crucible.

Therefore, by measuring the inner circumferential surface temperature of the crucible, the height of the silicon melt interface can be accurately measured while the single crystal ingot growing step is proceeding.

4 is a flowchart showing an example of the single crystal ingot growing method of the present invention.

First, after the melting process, the crucible position A of the reference temperature is confirmed (see S1 and S2).

The reference temperature is set within the range of 1428 ° C to 1430 ° C, which is the temperature of the silicon melt interface, and the position (A) of the inner circumferential surface of the crucible, which is measured at the reference temperature at the completion of melting, can be regarded as the position of the minimum silicon melt interface.

Next, during the ingot growing step, the crucible position B of the existing temperature is confirmed at set time intervals (see S3, S4, and S5).

As the ingot growth process proceeds, the neck, shoulder, and body are sequentially grown from the silicon melt, and as the silicon melt remaining in the crucible is reduced, the position of the silicon melt interface is lowered inside the crucible.

Therefore, the crucible position (B) of the reference temperature measured at the current time from the crucible position (A) of the reference temperature previously measured at intervals of 10 minutes is also lowered inside the crucible.

Next, the crucible position change (A-B = C) of the reference temperature is calculated (refer to S6)

However, in order to keep the melt gap constant during the ingot growing process, the crucible is divided into a case where the crucible is automatically controlled to raise by the set height D in the set time interval and a case where the crucible is not automatically controlled.

When the position change C is equal to the set height D, the crucible is raised by the set height D when the position of the crucible is automatically controlled, and if the position change C is different from the set height D, Is raised by the difference between the set position change C and the set height D (see S7, S8, and S9)

Usually, the crucibles are automatically controlled to rise by 1 mm at intervals of 10 minutes during the ingot growing process.

If the position change C is not more than 1 mm, the crucible is raised by the positional change C, and if the positional change C is less than 1 mm, the height of the crucible is controlled to be maintained It is possible.

As described above, during the ingot growing step, the position of the silicon melt interface is repeatedly determined according to the inner circumferential surface temperature of the crucible, and the rise of the crucible is controlled in accordance with the degree of change of the silicon melt interface so as to keep the melt gap constant And further, the quality of the single crystal ingot can be improved.

110: chamber 120: crucible
125: Crucible lifting unit 130: Heater
140: Insulation material 150:
160: cooling pipe 170: temperature sensor
175: sensor elevating part 180: control part

Claims (8)

A chamber for providing a closed space for growing a single crystal ingot;
A crucible provided in the chamber to melt polycrystalline silicon to form a silicon melt;
A crucible elevating portion for elevating the crucible;
A heater provided around the crucible for heating the crucible;
A heat shield member (nop) for maintaining the melt gap with the silicon melt interface and cooling the single crystal ingot;
A temperature sensor for measuring the inner circumferential surface temperature of the crucible;
A sensor elevator for raising / lowering the temperature sensor within a set upper and lower limit values in accordance with the weight of the polysilicon; And
A control unit for sensing a change in the inner circumferential surface position C of the crucible corresponding to the set reference temperature among the temperatures measured by the temperature sensor and raising the crucible according to the positional change C to maintain the melt gap constant; Include
Wherein,
Wherein the reference temperature is set at a temperature of a silicon melt interface contained in the crucible at an initial point of time when polycrystalline silicon is melted with a silicon melt. delete The method according to claim 1,
Wherein the temperature sensor comprises:
A single crystal ingot growing apparatus for measuring a temperature from 1428 캜 to 1430 캜 at a reference temperature. delete The method according to claim 1,
Wherein,
And controls the crucible lifting unit to raise the crucible by a set height (D) at a set time interval during the growth of the single crystal ingot. 6. The method of claim 5,
Wherein,
If the position change C is equal to the set height D, the crucible is raised by the set height D,
Wherein the crucible is raised by a difference between the positional change (C) and the set height (D) when the positional change (C) is different from the set height (D). The method according to claim 1,
Wherein,
If the position change (C) is 1 mm or more, the crucible is raised by the position change (C)
And retains the height of the crucible as it is when the positional change (C) is less than 1 mm. The method according to claim 1,
Wherein the temperature sensor comprises:
And an optical pyrometer provided outside the transparent window provided on the upper side of the chamber.

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