WO2016204411A1

WO2016204411A1 - Ingot growing apparatus and growing method therefor

Info

Publication number: WO2016204411A1
Application number: PCT/KR2016/005045
Authority: WO
Inventors: 김윤구
Original assignee: 주식회사 엘지실트론
Priority date: 2015-06-16
Filing date: 2016-05-12
Publication date: 2016-12-22
Also published as: KR20160148413A; KR101758980B1

Abstract

The present invention relates to an ingot growing apparatus and a growing method therefor, which can accurately measure the diameter and position of an ingot at the surface of molten silicon even when shaking of a seed cable occurs. In the ingot growing apparatus and the growing method therefor according to the present invention, an image sensor is provided in a different direction from the direction of an ingot measurement sensor, so that the diameter of an ingot can be accurately calculated by correcting the diameter of the ingot, measured by a diameter measurement sensor, depending on a change in the reference position, measured by the image sensor.

Description

Ingot growth apparatus and its growth method

The present invention relates to an ingot growth apparatus and a method for growing the same, which can accurately measure the diameter and position of the ingot at the silicon melt interface even when the seed cable is shaken.

In general, the Czochralski (CZ) method of growing single crystal silicon in an ingot form is widely used to manufacture a wafer.

In the growth process of the ingot by the Czochralski method, an inert gas is flowed into the chamber, a crucible provided in the chamber is heated to form a silicon melt, and a seed crystal, which is a seed crystal suspended on the end of the seed cable, is formed. Single crystal silicon is grown in the silicon melt in the radial direction, and when the diameter of the ingot grows to the target diameter, the ingot suspended on the seed cable is grown in the longitudinal direction while maintaining the target diameter while the seed cable is wound up.

At this time, the diameter of the ingot is measured by a diameter measuring sensor in order to control the diameter of the ingot, and the pulling speed of the seed cable is controlled according to the measured value.

In addition, the diameter of the ingot is not only easy to control, but in order to maintain the quality uniformly, the ingot growth process in the silicon melt interface to control the position of the ingot to the center of the crucible.

1 is a diagram illustrating an example in which a diameter sensor applied to a general ingot growth apparatus detects the diameter of an ingot.

As shown in FIG. 1, the diameter sensor 1 detects a meniscus formed between the silicon melt surface and the ingot, from the meniscus through the central portion c of the diameter sensor 1. The intensity of the light is detected.

Of course, the diameter measuring sensor 1 is movable in the horizontal direction.

Therefore, when the position of the meniscus moves from P1 to P3 as the diameter decreases, the central portion c of the diameter measuring sensor 1 moves from the meniscus as the diameter measuring sensor 1 moves. The strength may be recognized, and the diameter of the ingot may be measured according to the moving distance of the diameter measuring sensor 1.

However, since the body growth process proceeds in the form of a heavy ingot suspended on the seed cable, the seed cable may be shaken due to various factors, which is a limitation in accurately measuring the diameter of the ingot using a diameter measuring sensor. In addition, there is a problem that it is difficult to control the diameter of the ingot, or to control the position of the ingot to the center of the crucible.

Japanese Patent Laid-Open No. 2004-256340 discloses a pair of vibration preventing means disposed on both sides of the seed cable to prevent shaking of the seed cable, and the vibration preventing means mechanically pushes the seed cable in a lateral direction. Note is composed of forms.

However, according to the prior art, since the seed cable and the vibration damping means are directly rubbed, the metal foreign matter dropped from the seed cable or the vibration damping means may contaminate the silicon melt, and further, the seed cable may be broken during the process. There is this.

Further, according to the prior art, the vibration preventing means can be moved to prevent the shaking of the seed cable at that point, but since the ingot is suspended from the seed cable, the position of the ingot at the actual silicon melt interface is equal to the distance of the seed cable. It is hard to see that it moved.

Therefore, it is difficult to accurately determine the diameter and position of the ingot at the silicon melt interface by using the distance traveled by the conventional vibration preventing means, thereby controlling the diameter of the ingot or controlling the position of the ingot to the center of the crucible. There is a difficult problem.

The present invention has been made to solve the above-mentioned problems of the prior art, and provides an ingot growth apparatus and a method for growing the same, which can accurately measure the diameter and position of the ingot at the silicon melt interface even when the seed cable shakes. There is a purpose.

The present invention is a crucible containing a silicon melt; A seed cable provided at an upper side of the crucible and growing an ingot as the seed is immersed in the silicon melt; A diameter measuring sensor measuring a specific brightness of light at a boundary line between the silicon melt and the ingot while moving in a horizontal direction during the growth process of the ingot to measure the diameter of the ingot; An image sensor provided in a direction different from the diameter measuring sensor and measuring a predetermined reference position on an upper surface of the silicon melt; And a controller configured to correct the diameter of the ingot measured by the diameter sensor during the growth process of the ingot according to the change of the reference position measured by the image sensor.

On the other hand, the present invention is an ingot growth method of immersing a seed suspended in a seed cable in a silicon melt, and growing the ingot as it is slowly pulled, the light in the boundary between the silicon melt and the ingot while moving horizontally during the growth process of the ingot A first step of measuring the diameter of the ingot by measuring a specific brightness of the; A second step of measuring a predetermined reference position on the silicon melt upper surface in a direction different from the measurement position in the first step; And a third step of correcting the diameter of the ingot measured in the first step according to the change of the reference position measured in the second step.

Ingot growth apparatus and growth method according to the present invention by providing an image sensor in a direction different from the ingot measuring sensor, by correcting the diameter of the ingot measured by the diameter measuring sensor according to the change of the reference position measured by the image sensor, accurate ingot The diameter of can be calculated.

Therefore, even if shaking of the seed cable occurs, the diameter and position of the ingot can be accurately calculated at the silicon melt interface.

Further, by precisely controlling the diameter of the ingot in accordance with the target diameter, there is an advantage that can reduce the diameter deviation of the wafer.

In addition, by controlling the position of the ingot at the silicon melt interface in accordance with the center of the crucible, there is an advantage that the quality of the wafer can be maintained uniformly in the radial or longitudinal direction of the ingot.

1 is a view illustrating an example in which a diameter measuring sensor applied to a general ingot growth apparatus detects the diameter of an ingot.

2 is a view showing an example of an ingot growth apparatus according to the present invention.

3 is a view showing a reference position photographed in the image sensor applied to the present invention.

Figure 4 is a block diagram showing an example of the diameter control device in the present invention.

5 is a flowchart illustrating an example of an ingot growth method according to the present invention.

An embodiment of the ingot growth apparatus according to the present invention, the crucible containing the silicon melt; A seed cable provided at an upper side of the crucible and growing an ingot as the seed is immersed in the silicon melt; A diameter measuring sensor measuring a specific brightness of light at a boundary line between the silicon melt and the ingot while moving in a horizontal direction during the growth process of the ingot to measure the diameter of the ingot; An image sensor provided in a direction different from the diameter measuring sensor and measuring a predetermined reference position on an upper surface of the silicon melt; And a controller configured to correct the diameter of the ingot measured by the diameter sensor during the growth process of the ingot according to the change of the reference position measured by the image sensor.

Preferably, the image sensor is composed of a camera fixed to a specific position to take an image, and is located in the opposite direction to the diameter measuring sensor.

More preferably, the image sensor selects an arc of a specific length from an image of a portion of the circumference of the ingot on the silicon melt upper surface, and coordinates indicating the centers of two straight lines perpendicular to each other based on the arc. Measure to the reference position.

Preferably, the control unit selects an arc of a specific length from an image of a portion of the circumference of the ingot from the upper surface of the silicon melt when the diameter of the ingot becomes the target diameter, and orthogonal to each other based on the arc. And an input unit configured to receive coordinates representing centers of two straight lines as a reference value, and a calculation unit calculating a moving distance of the reference position by comparing the reference position measured by the image sensor with the reference value.

More preferably, the control unit, the diameter D ₀ of the ingot measured by the diameter measuring sensor, the moving distance R of the reference position measured by the image sensor, the image sensor from the diameter measuring sensor based on the center of the ingot In the case where is located θ, it includes a calculation unit for calculating the diameter correction value D ₁ of the ingot by the following equation.

On the other hand, an embodiment of the ingot growth method according to the present invention, in the ingot growth method of immersing the seed suspended in the seed cable in the silicon melt, and growing the ingot by gradually pulling, the silicon while moving horizontally in the growth process of the ingot A first step of measuring a diameter of an ingot by measuring a specific brightness of light at a boundary between the melt and the ingot; A second step of measuring a predetermined reference position on the silicon melt upper surface in a direction different from the measurement position in the first step; And a third step of correcting the diameter of the ingot measured in the first step according to the change of the reference position measured in the second step.

Preferably, in the second step, a first process of photographing a portion of the circumference of the ingot as an image on the upper surface of the silicon melt, and selecting an arc of a specific length from the image photographed in the first process, And a second process of measuring coordinates representing the centers of two straight lines perpendicular to each other as a reference position.

Preferably, in the third step, at a time when the diameter of the ingot becomes the target diameter, two arcs orthogonal to each other based on the arc are selected from the upper surface of the silicon melt, the arc having a specific length that is a part of the circumference of the ingot. A first step of receiving a coordinate representing the center of the straight line as a reference value, and a second step of calculating the moving distance of the reference position by comparing the reference position measured in the second step with the reference value.

More preferably, in the third step, the ingot diameter D ₀ measured in the first step, the moving distance R of the reference position measured in the second step, and the diameter of the ingot based on the center of the ingot. In the case of an angle θ between the measured point and the measured point of the reference position, the diameter correction value D ₁ of the ingot may be calculated by the following equation.

Hereinafter, with reference to the accompanying drawings for the present embodiment will be described in detail. However, the scope of the inventive idea of the present embodiment may be determined from the matters disclosed by the present embodiment, and the inventive idea of the present embodiment may be implemented by adding, deleting, or modifying components to the proposed embodiment. It will be said to include variations.

2 is a view showing an example of an ingot growth apparatus according to the present invention, Figure 3 is a view showing a reference position photographed in the image sensor applied to the present invention.

Ingot growth apparatus according to the present invention, the crucible 120, the heater 130, the cooling member 140 and the seed to grow the ingot (IG) inside the chamber 110, as shown in Figures 2 and 3 The cable 160 and the pulling speed controller 170 are provided, and the diameter measuring sensor 210 and the image sensor 220 and the control unit 230 to accurately measure the diameter of the ingot IG outside the chamber 110. Is provided.

The chamber 110 provides a predetermined closed space in which the ingot IG is grown, and an inlet 150 is provided at one upper side to allow an inert gas such as Ar to flow from the upper side to the lower side, and various components are provided. It is mounted inside / outside.

In an embodiment, first and second view ports W1 and W2 are provided at both upper portions of the chamber 110 to observe the inside thereof, and the diameter measuring sensor 210 and the image sensor 220 to be described below. Is provided outside the first and second view ports W1 and W2.

The crucible 120 is a container containing the silicon melt, and is rotatably installed inside the chamber 110. At this time, the crucible 120 is configured in a form that overlaps the quartz crucible and the graphite crucible so as to withstand the inflow of impurities and at the same time withstand high temperature.

The heater 130 is provided around the crucible 120, and as the crucible 120 is heated, the raw material of the poly form contained in the crucible 120 is liquefied into a silicon melt.

The cooling member 140 is provided to directly cool the ingot IG grown from the high temperature silicon melt, and is installed to hang above the crucible 120 and is grown from the silicon melt contained in the crucible 120. It is installed to surround the ingot IG at a predetermined interval.

The seed cable 160 is composed of a plurality of wires twisted, and has a strength and elasticity to lift a heavy ingot. Of course, a seed chuck on the bottom of the seed cable 160 is provided with a seed that is a seed crystal.

The pulling speed controller 170 is configured to control the pulling speed of the seed cable 160. In the embodiment, the seed cable 160 is a cylindrical drum which can be wound and released and a motor for rotating the drum. It may include, and may be an ADC (auto diameter controller) sensor unit to adjust the pulling speed in accordance with the diameter correction value of the ingot in conjunction with the control unit 230 to be described below, it is not limited.

The diameter measuring sensor 210 is installed to be movable in a horizontal direction outside the first view port W1 and is configured to measure a specific brightness of light emitted from the meniscus. That is, the diameter of the ingot may be measured according to the moving distance of the diameter measuring sensor 210.

Of course, in the case where the diameter of the ingot is actually varied or the seed cable 160 is shaken to move the ingot, the diameter measuring sensor 210 detects that the measured diameter of the ingot is changed.

The image sensor 220 is installed in a fixed form outside the second view port W2 and has a camera shape capable of capturing a predetermined reference position.

In this case, the image sensor 220 is provided in a different direction from the diameter measuring sensor 210, it is limited to the reference provided in the opposite direction in the embodiment.

In an exemplary embodiment, the reference position of the image sensor 220 selects an arc A of a specific length from an image of a portion of the circumference of the ingot on the upper surface of the silicon melt, as shown in FIG. It is measured by the coordinates (X, Y) representing the centers of two straight lines perpendicular to each other.

Accordingly, the image sensor 220 may detect that the position of the ingot is changed by shaking the seed cable 160 by measuring a reference position, and calculating the diameter correction value D ₁ of the ingot below. Applicable

The control unit 230 is provided to control the factors affecting the ingot growth process, in the embodiment corrects the diameter measurement value (D ₀ ) of the ingot according to the change (R) of the reference position, the diameter of the ingot It is limited to controlling the pulling speed P / S according to the value D ₁ , which will be described in detail below.

Figure 4 is a block diagram showing an example of the diameter control device applied to the ingot growth apparatus according to the present invention.

As shown in FIG. 3, the diameter control device applied to the present invention includes a diameter measuring sensor 210, an image sensor 220, a control unit 230 including an input unit 231 and a calculation unit 232, and a pulling speed. It is configured to include a controller 170.

First, a user inputs a reference value (X ₀ , Y ₀ ) through the input unit 231, and selects an arc of a specific length, which is a part of the circumference of the ingot, from the upper surface of the silicon melt at the time when the ingot becomes the target diameter, Coordinates representing the centers of two straight lines perpendicular to each other based on the arc are input as reference values (X ₀ , Y ₀ ).

In addition, the diameter sensor 210 and the image sensor 220 measures the diameter (D ₀ ) and the reference position (X ₁ , Y ₁ ) of the ingot in the opposite direction, respectively.

Thereafter, the calculator 232 compares the reference values (X ₀ , Y ₀ ) with the measured reference positions (X ₁ , Y ₁ ) to calculate the movement distance (R) of the reference position, and then the following [Equation 1] ] Can calculate the diameter correction value (D ₁ ) of the ingot, a correction factor can be added according to the process conditions.

At this time, D ₀ is the diameter of the ingot measured by the diameter measuring sensor 210, R is the moving distance of the reference position measured by the image sensor 220, θ is the diameter measurement based on the center of the ingot The image sensor 220 is positioned at an angle from the sensor 210.

For example, when the diameter measuring sensor 210 and the image sensor 220 are located in opposite directions, the diameter correction value D ₁ becomes a value obtained by subtracting the moving distance from the diameter measuring value D ₀ . (R) may be +, 0,-.

As such, when the diameter correction value D ₁ of the ingot is calculated by the calculating unit 232, the pulling speed controller 170 pulls speed according to the diameter correction value D ₁ of the ingot. ), So that the diameter of the ingot can be controlled to exactly match the target diameter.

Ingot growth method of the present invention proceeds the ingot body growth process at the set pulling speed (P / S) as shown in Figure 5, the operator inputs a reference value (see S1, S2).

The operator selects an arc (A) of a specific length, which is a part of the circumference of the ingot, when the diameter (D) of the ingot becomes the target diameter (D _T ), and the two straight lines perpendicular to each other based on the arc (A) are selected. Enter the coordinates representing the center as reference values (X ₀ , Y ₀ ). Of course, since the position of the reference arc for each process may vary, it is preferable that the operator checks each process and inputs the reference values (X ₀ , Y ₀ ).

Next, the diameter (D ₀ ) of the ingot is measured in a predetermined direction, and the reference position (X ₁ , Y ₁ ) of the ingot is measured in the opposite direction (see S3 and S4).

The diameter (D ₀ ) of the ingot and the reference position (X ₁ , Y ₁ ) of the ingot are measured in different directions with respect to the circumference of the ingot.

In an embodiment, the diameter as the measuring sensor is moved by measuring the specific brightness of the meniscus, by measuring a point on the other hand for measuring the diameter (D ₀₎ of the ingot, the meniscus in the image sensor is fixed, the ingot Measure the reference position of (X ₁ , Y ₁ ).

Of course, the relative position angle θ of the diameter sensor and the image sensor is also set in advance, which is applied in the following to calculate the diameter correction value D ₁ of the ingot.

Next, the moving distance R is calculated from the reference _values X ₀ and Y ₀ and the reference positions X ₁ and Y ₁ of the ingot (see S5).

The movement distance R may be +, 0,-, and when the movement distance R is +,-, as described above, the seed cable may be shaken to determine that the position of the ingot is changed.

Next, the diameter correction value D ₁ of the ingot is calculated according to the movement distance R and the measurement position θ (see S6).

The diameter correction value D ₁ of the ingot may be calculated by Equation 1 described above, and the diameter measurement value D ₀ is corrected in consideration of the moving distance R and the measurement position θ. .

Next, the pulling speed P / S of the ingot is controlled according to the diameter correction value D ₁ of the ingot (see S7).

Therefore, even if the position of the ingot varies due to the shaking of the seed cable or other factors, the diameter and position of the ingot can be accurately calculated at the silicon melt interface.

Furthermore, by precisely controlling the diameter of the ingot to the target diameter, it is possible to reduce the diameter deviation of the wafer, or by controlling the position of the ingot at the center of the crucible by controlling the position of the ingot at the silicon melt interface, so that The quality can be kept uniform.

The present invention can be applied to an ingot growth apparatus for growing a single crystal ingot by the Czochralski method and its growth method, whereby the quality of the single crystal ingot can be improved.

Claims

Crucible containing silicon melt;

A seed cable provided at an upper side of the crucible and growing an ingot as the seed is immersed in the silicon melt;

A diameter measuring sensor measuring a specific brightness of light at a boundary line between the silicon melt and the ingot while moving in a horizontal direction during the growth process of the ingot to measure the diameter of the ingot;

An image sensor provided in a direction different from the diameter measuring sensor and measuring a predetermined reference position on an upper surface of the silicon melt; And

And a control unit for correcting the diameter of the ingot measured by the diameter measuring sensor during the growth process of the ingot according to the change of the reference position measured by the image sensor.
The method of claim 1,

The image sensor,

Ingot growth device consisting of a camera that is fixed to a specific position to take an image.
The method of claim 1,

The image sensor,

Ingot growth apparatus is located in the opposite direction to the diameter measuring sensor.
The method of claim 1,

The image sensor,

An ingot growth apparatus for selecting an arc of a specific length from an image of a portion of the circumference of the ingot on the upper surface of the silicon melt, and measuring coordinates representing centers of two straight lines perpendicular to each other based on the arc as a reference position.
The method of claim 4, wherein

The control unit,

When the diameter of the ingot becomes the target diameter, the arc of a specific length is selected from an image of a portion of the circumference of the ingot on the upper surface of the silicon melt, and coordinates representing the centers of two straight lines perpendicular to each other based on the arc An input unit for inputting a reference value,

And an operation unit configured to calculate a moving distance of the reference position by comparing the reference position measured by the image sensor with the reference value.
The method according to any one of claims 1 to 5,

The control unit,

The ingot when the diameter D 0 of the ingot measured by the diameter sensor, the moving distance R of the reference position measured by the image sensor, and the angle θ where the image sensor is located from the diameter measuring sensor with respect to the center of the ingot, An ingot growth apparatus comprising an operation unit for calculating the diameter correction value of D 1 by the following equation.
In the ingot growth method of soaking a seed suspended in a seed cable in a silicon melt and growing the ingot as it is slowly pulled up,

A first step of measuring a diameter of an ingot by measuring a specific brightness of light at a boundary between the silicon melt and the ingot while moving horizontally during the growth of the ingot;

A second step of measuring a predetermined reference position on the silicon melt upper surface in a direction different from the measurement position in the first step; And

And a third step of correcting the diameter of the ingot measured in the first step according to the change of the reference position measured in the second step.
The method of claim 7, wherein

The second step,

A first process of photographing a portion of the circumference of the ingot as an image on the upper surface of the silicon melt;

And a second process of selecting an arc having a specific length from the image photographed in the first process, and measuring a coordinate representing the center of two straight lines perpendicular to each other based on the arc as a reference position.
The method of claim 8,

The third step,

When the diameter of the ingot becomes the target diameter, an arc of a specific length, which is a part of the circumference of the ingot, is selected from the upper surface of the silicon melt, and a coordinate representing the center of two straight lines perpendicular to each other based on the arc is input as a reference value. Receiving the first course,

And a second process of calculating a moving distance of the reference position by comparing the reference position measured in the second step with the reference value.
The method according to any one of claims 7 to 9,

The third step,

The diameter D 0 of the ingot measured in the first step, the moving distance R of the reference position measured in the second step, the point where the diameter of the ingot was measured based on the center of the ingot and the reference point were measured. Ingot growth method comprising the step of calculating the diameter correction value D 1 of the ingot by the following equation.