KR20180005424A - Single-crystal ingot growth apparatus and method of controlling the same - Google Patents

Abstract

The present invention relates to a single crystal ingot growth apparatus which comprises: a measuring rod disposed on a crucible; an image capturing unit including a lens unit which acquires image information on the measuring rod and a shadow of the measurement rod, and can move closer to or further away from the measurement rod; and a control unit generating a drive control signal for controlling the movement of the lens unit so as to vary the distance between the measurement rod and the lens unit, when at least one of the brightness and the focus is in error on the basis of the image information about images of the measurement rod and the shadow of the measurement rod. An objective of the present invention is to provide a single crystal ingot growth apparatus and a control method thereof, which can monitor the single crystal ingot growth without measurement errors.

Description

[0001] The present invention relates to a single crystal ingot growing apparatus and a method of controlling the same,

The present invention relates to a single crystal ingot growing apparatus and a control method thereof.

In order to manufacture a silicon wafer, monocrystalline silicon must first be grown in an ingot form, and a czochralski (CZ) method can be applied.

A single crystal ingot growing apparatus to which a czochralski (CZ) method is applied is a method of heating a crucible in a chamber to melt polycrystalline silicon in a crucible, immersing a single crystal seed crystal in molten silicon, The ingot can be grown to a single-crystal ingot having a desired diameter.

A measuring instrument for monitoring the growth process of the single crystal ingot may be provided in order to grow a polycrystalline ingot of good quality.

One of the conventional measuring apparatuses is a melt gap measuring apparatus for measuring the melt gap using a camera installed on the chip.

As a preliminary data for the melt gap measurement equipment, there is the disclosure number 10-2014-0097834.

However, the conventional melt-gap measuring equipment is incapable of measuring an accurate melt gap due to measurement errors due to blurred or out of focus images obtained from inside the chamber, for example, when the brightness or focus in the chamber changes, There is a problem that the monocrystalline ingot is defective.

The present invention is directed to solving the above-mentioned problems and other problems.

Another object of the present invention is to provide a monocrystalline ingot growing apparatus and a control method thereof capable of monitoring monocrystalline ingot growth without any measurement error.

According to an aspect of the present invention, there is provided a single crystal ingot growing apparatus including: a measuring rod disposed on a crucible; An imaging unit including a measurement unit and a lens unit that acquires image information about the shadow of the measurement bar and is movable at least toward or away from the measurement rod; And a controller for controlling the movement of the lens unit so as to vary the distance between the measurement rod and the measurement rod when at least one of brightness and focus is determined based on the image information of the measurement rod and the shadow image of the measurement rod, And a control unit for generating a control signal.

According to another aspect of the present invention, a method of controlling a single crystal ingot growing apparatus includes the steps of: acquiring image information about a measurement rod disposed on a crucible and a shadow of the measurement rod; Determining whether there is an error in at least one of brightness and focus based on the image of the measurement rod and the image of the shadow of the measurement rod; Generating a drive control signal for controlling the movement of the lens unit when at least one of the brightness and the focus is erroneous; And moving the lens unit in response to the drive control signal such that a distance between the measurement rod and the lens is varied.

Effects of the single crystal ingot growing apparatus and the control method thereof according to the present invention are as follows.

According to at least one of the embodiments of the present invention, the movement of the lens unit of the image photographing unit is controlled so that the brightness or the focus change is reflected even if the brightness or the focus within the chamber is varied, thereby preventing the measurement error of the melt gap There is an advantage that a single crystal ingot of excellent quality can be grown.

Further scope of applicability of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, such as the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

1 is a view showing a single crystal ingot growing apparatus according to an embodiment of the present invention.
2 is a detailed block diagram of the control unit of FIG.
3 is a block diagram showing an example of the lens control unit of FIG. 2 in detail.
FIG. 4 is a diagram illustrating an area including a measurement mark image obtained from an image capturing unit in order to calculate a brightness value.
5 is a block diagram showing another example of the lens control unit of FIG. 2 in detail.
6 is a flowchart illustrating a method of controlling a single crystal ingot growing apparatus according to an embodiment of the present invention.
FIG. 7A is a view showing an image obtained by a conventional image capturing unit.
FIG. 7B is a diagram illustrating an image acquired by the image capturing unit of the present invention.
8 is a view showing a melt gap according to the ingot length in the related art.
Fig. 9 is a diagram showing the melt gap according to the ingot length in the present invention. Fig.
10 is a graph showing the image recognition rates in the conventional and the present invention in a single crystal growing apparatus which are different from each other.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

1 is a view showing a single crystal ingot growing apparatus according to an embodiment of the present invention.

1, the single crystal ingot growing apparatus 100 includes a chamber 110, a crucible 120, a heating element 130, a crucible support 140, a side insulating material 152, a bottom insulating material 154, 160, a measuring bar 170, an image capturing unit 190, a controller 200, and a driver 210. [

Concretely, the crucible 120 may be a graphite crucible. In addition, the portion surrounding the outer side of the crucible 120 (hatched portion in FIG. 1) may be a quartz crucible.

The chamber 110 may be a space providing a growth environment for growing the monocrystalline ingot (I). The chamber 110 may have a view port 180 for viewing the interior and may include a body chamber 111, a dome chamber 112 and a pull chamber pull chamber, 113).

The view port 180 may be installed in one area of the dome chamber 112 but is not limited thereto.

The number of view ports 180 may correspond to the number of image capturing units 190. For example, when three image capturing units are provided, three viewports may also be provided.

The body chamber 111 may be positioned at the bottom and the dome chamber 112 may be positioned at the top of the body chamber 111 to serve as a lid. The body chamber 111 and the dome chamber 112 provide an environment for growing the polycrystalline silicon into the monocrystalline ingot I, and may be a cylinder having a receiving space therein. The pull chamber 113 may be located at the top of the dome chamber 112 and may be a space for pulling up the grown single crystal ingot I. Therefore, the single crystal ingot I grown in the space formed by the body chamber 111 and the dome chamber 112 can be pulled up by the pull chamber 113 in the upward direction.

The single crystal ingot I may be, for example, a single crystal ingot made of silicon, but is not limited thereto.

The crucible 120 may be provided inside the chamber 110, for example, the body chamber 111, and may accommodate a raw material melt SM for growing the single crystal ingot I. The material of the crucible 120 may be quartz, but is not limited thereto.

The crucible support 140 is positioned below the crucible 120 to support the crucible 120 and can also rotate the crucible 120 or raise or lower the crucible 120.

The heating element 130 may be disposed in the chamber 110, for example, the body chamber 111 such that the heating body 130 is spaced apart from the outer circumferential surface of the crucible 120.

The heating element 130 can heat the crucible 120 and the high-purity polycrystalline ingot stacked in the heated crucible 120 can be melted to become the melt SM. The heating element 130 may be, for example, a resistance heater or an induction heating type heater, but the invention is not limited thereto.

The side insulator 152 may be located on the side of the crucible 120 and may block heat from flowing out of the chamber 110 into the chamber 110 side. For example, the side insulator 152 may be positioned between the heating element 130 and the sidewall of the body chamber 111 to prevent the heat of the heating element 130 from leaking to the outside.

The lower thermal insulator 154 may be located below the crucible 120 and may prevent heat within the chamber 110 from escaping into the lower portion of the chamber 110. For example, the lower heat insulating material 154 may be positioned between the heat emitting body 130 and the bottom of the body chamber 111 to prevent the heat of the heat emitting body 130 from leaking to the outside.

Between the side insulator 152 and the bottom insulator 154, an exhaust port for evacuating gas or process by-products in the chamber 110 may be formed.

The heat shield 160 is disposed on the top of the crucible 120 and blocks heat from escaping from the melt SM contained in the crucible 120.

The measurement rod 170 may be disposed on the melt SM contained in the crucible 120 and coupled to the lower end of the thermal shutdown portion 160. [

The gap between the lower end of the heat shielding portion 160, specifically, the surface of the measuring rod 170 and the surface of the melt SM is called a melt gap. In order to improve the quality of monocrystalline ingots and increase the productivity, the melt gap should be kept constant.

The measuring rod 170 can serve as a reference in measuring the melt gap and is also referred to as a scale rod.

Based on the image of the measurement rod 170 and the shadow image of the measurement rod 170 reflected on the surface of the melt SM accommodated in the crucible 120 by the measurement rod 170, The melt gap can be measured based on the interval between the shadows of the ink droplet 170.

The image capturing unit 190 may acquire images related to the shadows of the measurement rod 170 and the measurement rod 170.

The image capturing unit 190 may include an image capturing unit 191 and a lens unit 193.

The image pickup unit 191 may include, for example, a plurality of CCDs (Charge-Coupled Devices) or a plurality of CMOSs (Complementary Metal Oxide Semiconductors). The image pickup unit 191 can acquire an image in the chamber 110 including the measurement bar 170 and the shadow of the measurement bar 170. [

The lens unit 193 can be disposed at the front end of the image pickup unit 191, that is, between the image pickup unit 191 and the view port 180. [ The lens unit 193 can be formed integrally with the image sensing unit 191 to configure the image sensing unit 190. The image capturing unit 190 may further include other components in addition to the image capturing unit 191 and the lens unit 193, but the present invention is not limited thereto.

The lens unit 193 may be composed of a lens array including a plurality of lenses, but the invention is not limited thereto.

The image of the measurement rod 170 and the measurement rod 170 is formed on the image pickup unit 191 through the lens array and the image pickup unit 191 forms the measurement rod 170 and the measurement rod 170 on the basis of this image, The image of the shadow of the user can be obtained. The thus obtained image may be provided to the control unit 200. [

The lens unit 193 may be movable in any of the x-axis, y-axis, and z-axis directions. The lens unit 193 is driven by the driving unit 210 and is movable in any direction of the x axis, the y axis, and the z axis.

Here, the z-axis may be the same direction as the length direction of the view port 180. Accordingly, when the lens unit 193 is moved along the z-axis direction, the lens unit 193 can be moved toward or away from the measurement rod 170. [

The lens unit 193 is coupled to the driving unit 210 and can be moved in any direction along the x-axis, the y-axis, and the z-axis in accordance with the driving of the driving unit 210.

The driving unit 210 may include, but is not limited to, at least one or more gear connecting shafts that connect, for example, at least one motor and at least one motor to each lens unit 193.

The driving unit 210 may be driven under the control of the control unit 200.

The control unit 200 can measure the melt gap based on the image obtained from the image capturing unit 190, that is, the image of the measurement rod 170 and the shadow image of the measurement rod 170. [

The control unit 200 may generate a drive control signal for moving the lens unit 193 based on the image of the measurement rod 170 and the shadow image of the measurement rod 170. [ The driving unit 210 is driven in response to the driving control signal so that the lens unit 193 of the image capturing unit 190 can be moved along at least one of the x-, y-, and z-axes.

As shown in FIG. 2, the controller 200 may include a melt gap measuring unit 201 and a lens controller 203.

The image of the measurement rod 170 and the shadow image of the measurement rod 170 obtained from the image capturing unit 190 are provided to the control unit 200 so that the melt gap measurement unit 201 and the lens control unit 200 of the control unit 200, (203), respectively.

The melt gap measurement unit 201 measures the melt gap between the measurement rod 170 and the shadow of the measurement rod 170 based on the measurement rod image acquired from the image capture unit 190 and the shadow image of the measurement rod 170 can do.

The measured melt gap information may be provided to an axis control unit (not shown). Based on the measured melt gap information, the axis control unit can check whether the melt gap is changed or not, and control the crucible 120 to move upward, for example, so that the melt gap maintains a constant gap when there is a change .

For example, as the single crystal ingot is grown, the amount of the melt SM accommodated in the crucible 120 is reduced, thereby lowering the surface of the melt SM downward. In this case, when the surface of the melt SM from which the shadow image of the measuring rod 170 is obtained is lowered downward, the position of the measuring rod 170 is maintained, while the position of the measuring rod 170 and the measuring rod 170 The larger the melt gap between the shadows. Thus, in order to reduce the melt gap and to remain the same as the previous melt gap, the crucible 120 may be moved in the upward direction.

On the other hand, the situation in the chamber 110, for example, the brightness or the focus, may vary during the growth of the single crystal ingot.

The brightness in the chamber 110 may vary depending on (1) the power intensity of the heating element 130, (2) the amount of the melt SM, (3) the variability of the melt gap, and the like.

In addition, the focal point in the chamber 110 may vary depending on (1) the amount of the melt SM, (2) the melt gap, and the like.

When the brightness or focus of the chamber 110 changes, the brightness or focus of the image of the measurement bar 170 or the shadow image of the measurement bar 170 in the image capturing unit 190 deteriorates and ultimately the measurement of the melt gap An error may occur. As a result, the accurate melt-gap measurement becomes impossible, and the melt gap is not maintained constantly, so that it is difficult or impossible to grow a single-crystal ingot of good quality.

The movement of the lens unit 193 of the image capturing unit 190 is controlled so that the brightness or the focus change is reflected even if the brightness or the focus of the chamber 110 is varied as described above. It is possible to grow a single crystal ingot of excellent quality.

To this end, the control unit 200 may include a lens control unit 203.

3, the lens control unit 203 may include a brightness calculating unit 205, a brightness determining unit 207, and a drive control signal generating unit 209. [

The brightness calculating unit 205 may receive the measurement bar image 310 of FIG. 4 obtained from the image capturing unit 190 and the shadow image 320 of FIG. 4 of the measurement bar 170.

If the brightness in the chamber 110 becomes excessively bright or dark, or if the focus deviates from the optimal focus period, the shadow image 320 of FIG. 4 is not distinguishable from the background image, . In this case, the measurement rod image 310 (FIG. 4) may also be increased or decreased in size.

In the present invention, it is possible to determine a change in brightness or a change in focus based on a certain area including a measurement stick image.

For this, as shown in FIG. 4, a certain area including the measurement rod image 310 can be set. Therefore, it is possible to extract a certain region including the measurement rod image based on the measurement rod image 310 obtained from the image capturing unit 190, and to calculate the average brightness value of the extracted constant region.

The predetermined region may include at least the measurement rod image 310. Specifically, the predetermined region may include the measurement rod image 310 and the background image adjacent to the measurement rod image.

The predetermined region may include, for example, 50 to 80 pixels along the horizontal direction and 20 to 50 pixels along the vertical direction, but the present invention is not limited thereto.

If the measurement rod image 310 exceeds the size of 80 pixels (horizontal) and 50 pixels (vertical), a certain area may be reset so that the measurement rod image 310 is included.

Any known technique can be applied to the technique of extracting a certain region from the measurement rod image 310. [ For example, an area including a predetermined number of pixels from the outermost border of the measurement rod image 310 may be extracted from the measurement rod image 310 obtained from the image photographing unit 190 to a predetermined area. However, I never do that.

The average brightness value of the extracted predetermined area may be provided to the brightness determination unit 207.

The brightness determining unit 207 can determine the brightness change or the focus change in the chamber 110 by comparing the average brightness value of the extracted certain region with the predetermined average brightness period.

The predetermined average brightness interval may be a brightness interval in which the measurement rod 170 can be clearly recognized. The predetermined average brightness period may be set through a repeated experiment on a predetermined area.

The determination result of the brightness determination unit 207 may be provided to the drive control signal generation unit 209.

The drive control signal generator 209 can generate a drive control signal according to the determination result input from the brightness determiner 207. [

For example, when the average brightness value of the predetermined region extracted by the brightness determination unit 207 is larger than the maximum value of the predetermined average brightness period, the drive control signal generation unit 209 determines that the lens unit 193 is in the ON state, Axis direction so as to move away from the z-axis direction. The lens unit 193 is moved away from the measuring rod 170 when the average brightness value of the extracted constant region is bright enough to make it difficult to recognize the measuring rod 170, The average brightness value of a certain region including the image, specifically the measurement rod image may be reduced so that it is ultimately included in the predetermined brightness average interval.

For example, when the average brightness value of the certain region extracted by the brightness determination unit 207 is smaller than the minimum value of the predetermined average brightness period, the drive control signal generation unit 209 controls the lens unit 193 Can be moved along the z-axis direction so as to be closer to the measuring bar 170. [ When the average brightness value of the extracted region is dark enough to recognize the measuring rod 170, the lens unit 193 is moved so as to come close to the measuring rod 170, The average brightness value of a certain region including the image, specifically the measurement rod image may be increased so that it is ultimately included within the predetermined brightness average interval.

The drive control signal generated from the drive control signal generator 209 may be provided to the driver 210. [

The driving unit 210 can be driven to move the lens unit 193 toward the front or rear of the image pickup unit 191 along the z axis direction in response to the drive control signal provided from the drive control signal generator 209. [

According to the above invention, the lens unit 193 is moved on the basis of the average brightness value of a certain region extracted from the image capturing unit 190, and the measurement rod image 310 having the optimum brightness is obtained from the image capturing unit 190 .

The present invention moves the lens unit 193 on the basis of the focus value of the measurement rod image 310 obtained from the image pickup unit 190 and outputs the measurement probe image having the best focus from the image pickup unit 190 310).

As shown in FIG. 5, may include a focus calculation unit 211, a focus determination unit 213, and a drive control signal generation unit 209.

The focus calculating unit 211 may be integrated with the brightness calculating unit 205 shown in FIG. 3 and may be called an calculating unit, but the present invention is not limited thereto.

The focus determination unit 213 may be integrated with the brightness determination unit 207 shown in FIG. 3 and may be called a determination unit, but the present invention is not limited thereto.

The drive control signal generation unit 209 may be the drive control signal generation unit shown in FIG. 3, but it is not limited thereto.

The focus calculator 211 may include a focus calculator 211 in the lens controller 203 for calculating the focus value of the measurement rod image from the measurement rod image 310 acquired from the image capture unit 190. [ The measurement rod image 310 calculated by the focus calculation unit 211 may be provided to the focus determination unit 213.

The focus determination unit 213 can determine whether the focus value of the measurement rod image 310 calculated by the focus calculation unit 211 coincides with a predetermined focus value.

If it is determined that the focus value of the measurement rod image 310 does not coincide with the preset focus value, the drive control signal generator 209 sets the focus value of the measurement rod image to the lens unit 193 ) Can be generated.

The driving unit 210 may move the lens unit 193 in response to the driving control signal provided from the focus determination unit 213. [ The movement of the lens unit 193 can be continued until the focus value of the measurement rod image matches the focus value by the focus determination unit 213. [ When the focus value of the measurement rod image coincides with the focus value, the lens unit 193 can be held at the current position without moving any further.

As another example, the focus determination unit 213 may determine whether the focus value of the measurement rod image deviates from a preset focus interval.

As a result of the determination, if the focus value of the measurement rod deviates from the predetermined focus range, the drive control signal generator 209 can move the lens unit 193 so that the focus value of the measurement rod image is included in the preset focus interval have. The movement of the lens unit 193 can be continued until the focus value of the measurement rod image is included in the preset focus interval by the focus determination unit 213. [ When the focus value of the measurement rod image is included in the preset focus interval, the lens unit 193 can be held at the current position without moving any further.

The present invention can move the lens unit 193 according to the brightness change shown in Fig. 3 (first embodiment), move the lens unit 193 according to the focus change shown in Fig. 5 2 embodiment), or the lens unit 193 may be moved in consideration of both the brightness change (FIG. 3) and the focus change (FIG. 5) (third embodiment).

FIG. 7A is a view showing an image obtained by a conventional image capturing unit, and FIG. 7B is a view illustrating an image obtained by an image capturing unit of the present invention. FIG. 8 is a view showing a melt gap according to an ingot length in the related art, and FIG. 9 is a diagram showing a melt gap according to an ingot length in the present invention.

As shown in FIG. 7A, the image obtained by the image capturing unit in the related art, specifically, the measurement rod image and the shadow image of the measurement rod 170 are not clearly recognized because the size is reduced due to the brightness or the focus change, .

7B, the measurement rod image 310 obtained by the image capturing unit 190 and the shadow image 320 of the measurement rod 170 are adjusted so as to be focused on the optimum brightness. By moving the lens unit 193, the measurement rod image 310 and the shadow image 320 of the measurement rod 170 can be clearly recognized.

As shown in FIG. 7A, when the measurement rod image and the shadow image of the measurement rod 170 are not clearly recognized, the measurement pattern image is instantaneously missed as in the case of the area A, as shown in FIG. 8, A measurement error may be generated which continuously misses the measurement pattern image.

On the other hand, as shown in FIG. 7B, when the measurement rod image and the shadow image of the measurement are clearly recognized, accurate melt gap measurement can be performed without measurement error as shown in FIG. 9, .

10 is a graph showing the image recognition rates in the conventional and the present invention in a single crystal growing apparatus which are different from each other.

10, the recognition rates in the conventional single crystal growth apparatus # 1 and the present invention are 79.6% and 93.9%, respectively. In the single crystal growth apparatus of the present invention, Is much better than the conventional method.

Likewise, in the other single crystal growth apparatuses # 2 and # 3, the recognition rate for the image obtained by the image capturing unit 190 is much better than that in the conventional art.

6 is a flowchart illustrating a method of controlling a single crystal ingot growing apparatus according to an embodiment of the present invention.

6 illustrates a third embodiment (a method of moving the lens unit 193 in consideration of both the brightness change and the focus change), but the first embodiment and the second embodiment are also possible.

1 to 3, 5 and 6, the image capturing unit 190 acquires images of the shadows of the measurement rod 170 and the measurement rod 170 provided at the lower end of the traction unit 160 (S301). The shadow of the measuring rod 170 can be reflected on the surface of the melt SM accommodated in the crucible 120.

In the chamber 110, the measurement rod 170 and the measurement rod shadow can be obtained as an image as a subject of the image capture unit 190. The measurement rod image thus obtained and the shadow image of the measurement rod 170 The image information may be provided to the control unit 200.

The control unit 200 may calculate an average brightness value and a focus value based on the image information provided from the image acquisition unit (S303).

In order to calculate the average brightness value, a certain region including at least the measurement mark image may be set in the image information. The average brightness value of a certain region may be calculated based on the brightness values of the pixels included in the predetermined region.

In order to calculate the focus value, the average brightness value of the pixels included in the border area of the measurement bar image adjacent to the background image in the image information is calculated, and the average brightness value of the pixels included in the border area of the measurement bar image is measured The average brightness value of the pixels included in the remaining region of the measurement rod image excluding the edge region of the image is compared and the focus value can be calculated based on the comparison result.

There are various methods for calculating the focus value, and various methods for calculating the focus value can also be included in the scope of the present invention.

The controller 200 may determine whether the average brightness value of the predetermined area is out of the preset average brightness interval (S305).

The predetermined average brightness period may be a brightness period in which the measuring rod 170 can be clearly recognized.

Therefore, if the average brightness value of the predetermined region is included within the preset average brightness period, the measurement rod image or the shadow image of the measurement rod 170 can be clearly recognized through the image capturing unit 190, Gap measurement may be possible.

The controller 200 may generate a first drive control signal for moving the lens unit 193 when the average brightness value of the predetermined area is out of the preset average brightness period. The first drive control signal may be a control signal for causing the lens unit 193 to move so that the average brightness value of a certain region is included within a predetermined average brightness period.

In response to the first driving control signal provided from the controller 200, the driving unit 210 drives the lens unit 193 in the z-axis direction, that is, until the average brightness value of the certain area is included in the predetermined average brightness period, (S307). Accordingly, the movement of the lens unit 193 can cause the distance between the lens unit 193 and the measuring rod 170 to approach or depart.

When the average brightness value of a certain region is included in the predetermined average brightness region due to the movement of the lens unit 193, the controller 200 can determine whether the calculated focus value is included in the predetermined focus region (S309 ).

The predetermined focus interval may be a focus interval in which the measurement rod 170 can be clearly recognized.

Although not shown, after step S309 is performed, step S305 may be performed, but this is not limited thereto.

If the calculated focus value deviates from a preset focus period, the controller 200 may generate a second drive control signal for moving the lens unit 193.

The driving unit 210 responds to the second driving control signal provided from the control unit 200 so that the lens unit 193 moves in the z-axis direction, that is, in the viewport 180 until the calculated focus value is included in the predetermined focus period And may be driven to move along the longitudinal direction. Accordingly, the movement of the lens unit 193 can cause the distance between the lens unit 193 and the measuring rod 170 to approach or depart.

When the calculated average value of brightness of the certain region is included in the predetermined average brightness period and the calculated focus value is included in the predetermined focal region, the lens unit 193 can be kept in the current state without being moved any more (S311).

If the lens unit 193 is moved (S305 and S307) so that the average brightness value of the certain region is included in the predetermined average brightness period, the lens unit 193 is moved again so that the focus value is included in the predetermined focus region (S309 and S307), the average brightness value of a certain region may be again out of the predetermined average brightness period. In this case, the process proceeds to S305 and S307, and the lens unit 193 may be moved such that the average brightness value of the certain region is included in the predetermined average brightness period.

The foregoing detailed description should not be construed in all aspects as limiting and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

100: Monocrystalline ingot growing apparatus
110: chamber
120: Crucible
130: heating element
152, 154: Insulation
160:
170: Measuring rod
180: Viewport
190:
191:
193: lens unit
200:
210:
201: Melting gap measuring part
203: lens control unit
205: Brightness calculating section
207:
209: drive control signal generator
211: Focus calculation unit
213: Focus determination unit
SM: melt

Claims (13)

A measuring rod disposed on the crucible;
An imaging unit including a measurement unit and a lens unit that acquires image information about the shadow of the measurement bar and is movable at least toward or away from the measurement rod; And
A driving control unit for controlling the movement of the lens unit so as to vary the distance between the measurement rod and the measurement rod when at least one of the brightness and the focus is in error based on the image of the measurement rod and the image of the shadow of the measurement rod, And a control section for generating a signal. The method according to claim 1,
Wherein,
A brightness calculating unit for calculating an average brightness of a certain region including the measurement bar image;
A brightness determining unit determining whether the calculated average brightness value is out of a preset average brightness period; And
And a drive control signal generator for generating a drive control signal for controlling the movement of the lens unit so that the measured average brightness value approaches or deviates from the measurement rod when the calculated average brightness value deviates from a predetermined average brightness interval. 3. The method of claim 2,
Wherein the drive control signal generator comprises:
And generates a drive control signal for controlling the lens unit to move away from the measuring rod when the calculated average brightness value is larger than the maximum value of the predetermined average brightness period. 3. The method of claim 2,
Wherein the drive control signal generator comprises:
And generates a drive control signal for controlling the lens unit to be closer to the measuring rod when the calculated average brightness value is larger than the minimum value of the predetermined average brightness period. 3. The method of claim 2,
Wherein the drive control signal generator comprises:
And controls the lens unit to move until the average brightness value is included within the predetermined average brightness period. 6. The method according to any one of claims 1 to 5,
Wherein,
A focus calculating unit for calculating a focus value from the measurement rod image;
A focus determiner for determining whether the calculated focus value deviates from a preset focus interval; And
And a drive control signal generator for generating a drive control signal for controlling the movement of the lens unit so that the calculated focus value is included in the predetermined focus interval when the calculated focus value deviates from a preset focus interval, Ingot growth apparatus. 6. The method according to any one of claims 1 to 5,
Wherein,
A focus calculating unit for calculating a focus value from the measurement rod image;
A focus determiner for determining whether the calculated focus value coincides with a predetermined focus value; And
And a drive control signal generator for generating a drive control signal for controlling the movement of the lens unit so that the calculated focus value coincides with the predetermined focus value when the calculated focus value does not match the preset focus value A single crystal ingot growing apparatus. Acquiring image information about a measurement rod disposed on a crucible and a shadow of the measurement rod;
Determining whether there is an error in at least one of brightness and focus based on the image of the measurement rod and the image of the shadow of the measurement rod;
Generating a drive control signal for controlling the movement of the lens unit when at least one of the brightness and the focus is erroneous; And
And moving the lens unit in response to the drive control signal so as to vary the distance from the measuring rod. 9. The method of claim 8,
The step of determining whether there is an error includes:
Calculating an average brightness of a certain region including the measurement rod image; And
Determining whether the calculated average brightness value is out of a preset average brightness period,
Wherein the step of moving the lens unit comprises:
And controlling the movement of the lens unit so that the distance between the measurement rod and the measurement rod is reduced when the calculated average brightness value deviates from a preset average brightness interval. 10. The method of claim 9,
Wherein the step of generating the drive control signal comprises:
And controlling the lens unit to move away from the measuring rod in response to the drive control signal when the calculated average brightness value is larger than the maximum value of the predetermined average brightness period . 10. The method of claim 9,
Wherein the step of generating the drive control signal comprises:
And controlling the lens unit to be closer to the measuring rod in response to the drive control signal when the calculated average brightness value is larger than the minimum value of the predetermined average brightness period. 12. The method according to any one of claims 8 to 11,
The step of determining whether there is an error includes:
Calculating a focus value from the measurement rod image; And
And determining whether the calculated focus value deviates from a preset focus interval,
Wherein the step of moving the lens unit comprises:
And controlling movement of the lens unit such that the calculated focus value is included in the predetermined focal interval when the calculated focal value deviates from a predetermined focal interval. 12. The method according to any one of claims 8 to 11,
The step of determining whether there is an error includes:
Calculating a focus value from the measurement rod image; And
And determining whether the calculated focus value coincides with a predetermined focus value,
Wherein the step of moving the lens unit comprises:
And controlling the movement of the lens unit so that the calculated focus value coincides with the preset focus value if the calculated focus value does not match the preset focus value.

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