WO2014115948A1

WO2014115948A1 - Single-crystal ingot growth apparatus

Info

Publication number: WO2014115948A1
Application number: PCT/KR2013/008660
Authority: WO
Inventors: Seong Chul Ahn
Original assignee: Lg Siltron Incorporated
Priority date: 2013-01-23
Filing date: 2013-09-27
Publication date: 2014-07-31
Also published as: KR101390804B1

Abstract

Disclosed is a single-crystal ingot growth apparatus including a chamber, a crucible placed within the chamber and configured to accommodate a melt that is a raw material for single-crystal growth, a top insulator located at an upper end of the crucible, the top insulator having a central first opening and a second opening provided between an inner circumferential surface and an outer circumferential surface of the top insulator, a camera configured to capture an image of the melt and a single-crystal ingot that is being grown, through the first opening and the second opening and to output image data, and a detector configured to calculate a diameter of the single-crystal ingot that is being grown, based on the image data.

Description

SINGLE-CRYSTAL INGOT GROWTH APPARATUS

Embodiments relate to a single-crystal ingot growth apparatus.

Sapphire is a crystal grown as alumina (Al₂O₃) is fused at 2050℃ and then gradually cooled. Sapphire, which is a single-crystal of alumina, may transmit broad wavelength light and have excellent mechanical properties, heat-resistance, and corrosion-resistance as well as high hardness, thermal conductivity, electric resistance, and shock-resistance. As sapphire is non-porous and has high dielectric strength, sapphire makes an ideal substrate for epitaxial growth.

Representative methods for single-crystal growth of sapphire include Bernoulli s method, Heat Exchange Method (HEM), Edge-defined Film-fed Growth (EFG), the Czochralski process, and the Kyropoulos process.

The Kyropoulos process advantageously exhibits lower equipment price and production costs and fewer defects than the Czochralski process. The Kyropoulos process is similar to the Czochralski process, but implements single-crystal growth only via rising of a single-crystal without rotation of the single-crystal.

Embodiments provide a single-crystal ingot growth apparatus, which may accurately calculate the diameter of a single-crystal ingot in real time during growth of the single-crystal ingot, and which may adjust the growth rate of the single-crystal ingot based on the calculated diameter of the single-crystal ingot.

In accordance with an embodiment, there is provided a single-crystal ingot growth apparatus including a chamber, a crucible placed within the chamber and configured to accommodate a melt that is a raw material for single-crystal growth, a top insulator located at an upper end of the crucible, the top insulator having a central first opening and a second opening provided between an inner circumferential surface and an outer circumferential surface of the top insulator, a camera configured to capture an image of the melt and a single-crystal ingot that is being grown, through the first opening and the second opening and to output image data, and a detector configured to calculate a diameter of the single-crystal ingot that is being grown, based on the image data.

The first opening may take the form of a circle having a predetermined diameter, and the second opening may take the form of a line having a predetermined length and width.

The second opening may originate from the first opening so as to extend between the inner circumferential surface and the outer circumferential surface.

The second opening may expose a boundary between the melt and the single-crystal ingot that is being grown. The second opening may be spaced apart from the outer circumferential surface.

The second opening may reach both the inner circumferential surface and the outer circumferential surface.

The second opening may include a plurality of first sub-openings, and the plurality of first sub-openings may be spaced apart from one another between the inner circumferential surface and the outer circumferential surface.

The top insulator may further include a third opening, and the third opening and the second opening may be symmetrical to each other on the basis of the first opening.

The top insulator may further include a third opening including a plurality of second sub-openings, and the first sub-openings and the second sub-openings may be symmetrical to each other on the basis of the first opening.

The top insulator may include a first insulator configured to reflect radiant heat generated from the melt into the crucible, the first insulator including a single layer, and a second insulator placed over the first insulator, the second insulator including a stack of a plurality of layers, and each of the first insulator and the second insulator may include the first opening and the second opening.

The single-crystal ingot growth apparatus may further include a light source located at an upper end of the chamber and configured to emit light having a preset wavelength to the melt and the single-crystal ingot that is being grown, through the second opening.

In accordance with another embodiment, there is provided a single-crystal ingot growth apparatus including a chamber, a crucible placed within the chamber and configured to accommodate a melt that is a raw material for single-crystal growth, a top insulator located at an upper end of the crucible, the top insulator having a central first opening and a second opening provided between an inner circumferential surface and an outer circumferential surface of the top insulator, a camera configured to capture an image of the melt and a single-crystal ingot that is being grown, through the first opening and the second opening and to output image data, a detector configured to calculate a diameter of the single-crystal ingot that is being grown, based on the image data, and a controller configured to adjust a growth rate of the single-crystal ingot based on the calculated diameter of the single-crystal ingot.

The preset wavelength may be equal to or greater than 600nm and is equal to or less than 450nm. The camera may output the image data based on the result captured in a state in which the light source emits light.

The single-crystal ingot growth apparatus may further include a heater provided between the crucible and the chamber to heat the crucible, a seed connector to which a seed crystal is secured, and a transfer unit configured to raise or lower the seed connector, and the controller may control at least one of a temperature of the heater and a rising velocity realized by the transfer unit based on the calculated diameter of the single-crystal ingot.

The camera may capture an image through the first opening when the seed crystal comes into contact with a surface of the melt, and then output first image data based on the captured result, and the camera may capture an image of a boundary between the single-crystal ingot that is being grown and the melt, through the second opening, and then output second image data based on the captured result.

The second image data may be output continuously or at a preset time interval during growth of the single-crystal ingot.

The detector may detect first coordinates based on the first image data and stores the detected first coordinates, and detect second coordinates based on the second image data and stores the detected second coordinates, thereby calculating the diameter of the single-crystal ingot based on the stored first coordinates and second coordinates.

The diameter of the single-crystal ingot may be calculated continuously or at a preset time interval during growth of the single-crystal ingot.

According to embodiments, it is possible to accurately calculate the diameter of a single-crystal ingot in real time during growth of the single-crystal ingot, and to adjust the growth rate of the single-crystal ingot based on the calculated diameter of the single-crystal ingot.

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.

In the drawings:

FIG. 1 shows a single-crystal ingot growth apparatus according to an embodiment;

FIG. 2 shows a first embodiment of a top insulator shown in FIG. 1;

FIG. 3 shows a second embodiment of the top insulator shown in FIG. 1;

FIG. 4 shows a third embodiment of the top insulator shown in FIG. 1;

FIG. 5 shows a fourth embodiment of the top insulator shown in FIG. 1;

FIG. 6 shows a fifth embodiment of the top insulator shown in FIG. 1;

FIG. 7 shows a sixth embodiment of the top insulator shown in FIG. 1;

FIG. 8 is a flowchart showing an embodiment of a method of detecting the diameter of a single-crystal ingot using a detector shown in FIG. 1; and

FIG. 9 shows an embodiment of a method of calculating the diameter of a single-crystal ingot shown in FIG. 6.

Hereinafter, embodiments will be clearly understood from a description of the accompanying drawings and the embodiments.

In the following description of the embodiments, when an element such as a layer (film), region, pattern or structure is referred to as being formed "on" or "under" another element, such as a layer (film), region, pad or pattern, it can be directly "on" or "under" the other element or be indirectly formed with intervening elements therebetween. In addition, it will be understood that "on" or "under"the element may be described relative to the drawings.

In the drawings, the size may be exaggerated, omitted or schematically illustrated for clarity and convenience. In addition, the size of each constituent element does not wholly reflect an actual size thereof. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings. Hereinafter, a single-crystal ingot growth apparatus according to the embodiments will be described with reference to the accompanying drawings.

FIG. 1 shows a single-crystal ingot growth apparatus 100 according to an embodiment.

Referring to FIG. 1, the single-crystal ingot growth apparatus 100 includes a chamber 101, a crucible 110, a crucible support base 120, a heater 130, a sidewall insulator 135, a bottom insulator 140, a top insulator 150, a seed connector 160, a transfer unit 170, a light source 210, a camera 230, a detector 240, and a controller 250. For example, the single-crystal ingot growth apparatus 100 may be designed to grow a sapphire single-crystal via Kyropoulos growth, but is not limited thereto.

The chamber 101 may be a space that provides a growth environment to grow a single-crystal ingot I.

The crucible 110 may be provided within the chamber 101, to accommodate a raw material melt for growth of the single-crystal ingot I. The crucible 110 may be formed of tungsten, but is not limited thereto.

The crucible support base 120 may be located below the crucible 110 to support the crucible 110. The crucible support base 120 may be formed of any material that exhibits excellent thermal conductivity and heat-resistance as well as high resistance to thermal shock and is not easily deformed by heat owing to a low thermal expansion rate thereof. For example, the crucible support base 120 may be formed of molybdenum, but is not limited thereto.

The heater 130 may be provided in the chamber 101 at a constant spacing with an outer circumferential surface of the crucible 110, to heat the crucible 110. The heater 130 may be formed of tungsten, but is not limited thereto.

The heater 130 may be positioned to surround the sidewall and the bottom of the crucible 110, but is not limited thereto. Alternatively, the heater 130 may be located only around the sidewall of the crucible 110. The heater 130 may heat the crucible 110. As the temperature of the crucible 110 is raised via heating of the heater 130, a raw material in the form of a polycrystal lump may be changed into a melt.

The sidewall insulator 135 may be located around the sidewall of the crucible 110 to prevent heat within the chamber 101 from escaping through the sidewall of the chamber 101. For example, the sidewall insulator 135 may be located between the heater 130 and the sidewall of the chamber 101, to prevent heat of the heater 130 from escaping the chamber 101.

The bottom insulator 140 may be located below the crucible 110 to prevent heat within the chamber 101 from escaping through the bottom of the chamber 101. For example, the bottom insulator 140 may be located between the heater 130 and the bottom of the chamber 101, to prevent heat of the heater 130 from escaping through the bottom of the chamber 101.

The top insulator 150 may be located above the crucible 110, to prevent heat from escaping through the top of the crucible 110.

The seed connector 160 may be located above the crucible 110. A seed crystal may be secured to one end of the seed connector 160, and the other end may be connected to the transfer unit 170. The seed connector 160 may take the form of a shaft.

The transfer unit 170 may be connected to the seed connector 160 to raise or lower the seed connector 160 within the chamber 101.

The top insulator 150 may have a first opening, which is a central opening for entrance/exit of the single-crystal ingot I through the top of the crucible 110, and a second opening which is used for image capture of the camera that will be described hereinafter.

FIG. 2 shows a first embodiment 150 of the top insulator shown in FIG. 1.

Referring to FIG. 2, the top insulator 150 may include a first opening 201 as a central opening, and a second opening 310 extending from the first opening 201. The top insulator 150 may take the form of a circular disc.

The first opening 201 may be a circular opening having a predetermined diameter, but is not limited thereto. Alternatively, the first opening 201 may be polygonal or elliptical opening.

The second opening 310 may be formed in a region between an inner circumferential surface 301 and an outer circumferential surface 302 of the top insulator 150. Specifically, the second opening 310 may take the form of a line, which extends from the inner circumferential surface 301 to the outer circumferential surface 302 and has a predetermined length L1 and width W, but is not limited thereto.

The second opening 310 may expose a boundary 401 between a melt M within the crucible 110 and the single-crystal ingot I to be transversely grown.

The length L1 of the second opening 310 may be less than a distance from the inner circumferential surface 301 to the outer circumferential surface 302. Hence, one end of the second opening 310 may be spaced apart from the outer circumferential surface 302.

For example, the length L1 of the second opening 310 may be in a range of 50mm to 100mm, and the width W of the second opening 310 may be in a range of 1mm to 10mm. The length L1 of the second opening 310 may be determined according to the size of the top insulator 150 or the diameter of the ingot to be grown. If the width W of the second opening 310 is less than 1 mm, the camera 230 cannot capture an image of the boundary between the melt and the single-crystal ingot through the second opening 310. In addition, if the width W of the second opening 310 exceeds 10mm, the top insulator 150 may not function as an insulator due to great heat loss.

The top insulator 150 may be comprised of a first insulator 152, a second insulator 154, and a third insulator 156.

The first insulator 152 may reflect radiant heat generated from the melt M accommodated in the crucible 110 into the crucible 110. The first insulator 152 may be a single layer formed of molybdenum or tungsten that exhibits excellent thermal insulation. The thickness of the first insulator 152 may be in a range of 5mm to 10mm.

The second insulator 154 may be placed over the first insulator 152, and in turn the third insulator 156 may be placed over the second insulator 154. Each of the second and

third insulators

154 and 156 may be a stack of a plurality of layers, and an air gap may be present between the respective neighboring layers to provide insulation.

For example, each of the second and

third insulators

154 and 156 may include a first layer as a lowermost layer, and a plurality of second layers sequentially stacked over the first layer. The first layer may be formed of tungsten, and the second layers may be formed of molybdenum. To enhance thermal insulation, the number of the second layers included in the third insulator 156 may be greater than the number of the second layers included in the second insulator 154. The second and

third insulators

154 and 156 may be supported by an upper end of the heater 130. Each of the first to

third insulators

152, 154 and 156 may have the first opening 201 and the second opening 310 as described above.

The light source 210 may be located above the top insulator 150 to emit light through the second opening 310.

For example, the light source 210 may be located at an upper end of the chamber 101, and emit light having a preset wavelength through the second opening 320 toward the boundary 401 between the melt M accommodated in the crucible 110 and the single-crystal ingot I to be grown. In this case, the wavelength of light emitted may be equal to or greater than 600nm, and may be equal to or less than 450nm. Emission of light having the above-described wavelength range serves to clearly identify the boundary 401 between the melt M and the single-crystal ingot I by the camera 230.

A viewport 220 may be provided at the upper end of the chamber 101 to ensure observation of the interior of the chamber 101. The second opening 310 may be aligned with the viewport 220, and the boundary 401 between the melt M and the single-crystal ingot I may be observed from the outside of the chamber 101 through the viewport 220 and the second opening 310.

The camera 230 may capture an image of the boundary 401 between the melt M and the single-crystal ingot I through the viewport 220, the first opening 201, and the second opening 310, and output image data. That is, the camera 230 may continuously capture an image of the single-crystal ingot I that is being grown in real time through the viewport 220 and the second opening 310, and output image data.

For example, the camera 230 may capture an image in a state in which the light source 210 emits light, which ensures acquisition of a clear image of the boundary 401 between the melt M and the single-crystal ingot I. This is because the interior of the crucible 110 is exposed to excessively bright and intense light, such that identification of the boundary 401 between the melt M and the single-crystal ingot I may be difficult. The camera 230 may be a photo-image camera or a thermal-image camera.

The camera 230 may capture an image through the viewport 220 and the first opening 201 when a seed crystal comes into contact with a surface of the melt M, and then output first image data ID1 based on the captured result. In addition, the camera 230 may capture an image of the boundary 401 between the single-crystal ingot I that is being grown and the melt M, through the viewport 220 and the second opening 310, and then output second image data ID2 based on the captured result. In this case, the second image data ID2 may be acquired continuously or at a preset time interval while the single-crystal ingot I is being grown.

The detector 240 serves to detect the diameter of the single-crystal ingot I that is being grown, based on the image data provided from the camera 230.

FIG. 8 is a flowchart showing an embodiment of a method of detecting the diameter of the single-crystal ingot I using the detector 240 shown in FIG. 1.

Referring to FIG. 8, first image data ID1 is received from the camera 230 (S110).

Next, first coordinates P1 where a seed crystal comes into contact with the melt M are detected from the first image data ID1, and the detected first coordinates P1 are stored (S120).

For example, a binarized first image may be extracted by performing binarization on the first image data ID1, and then the first coordinates P1 may be detected from the extracted binarized first image. The detected first coordinates P1 may be stored.

In this case, image binarization may utilize global binarization and regional binarization.

Global binarization may include inter-class dispersion, entropy application, histogram stretching, and moment maintenance. Regional binarization may include utilization of a window region (threshold value), local contact technique, logical level technique, brightness variation of a character based on properties of an object within a window, YDH technique, Object Attribute Thresholding (QAT) technique, local intensity gradient technique, dynamic threshold algorithm, and integrated function technique.

Next, second image data ID2 is received from the camera 230 (S130).

Next, second coordinates P2 of the boundary 401 between the melt M and the single-crystal ingot I that is being grown are detected from the second image data ID2, and the detected second coordinates P2 are stored (S140).

For example, a binarized second image may be extracted by performing binarization on the second image data ID2, and then the second coordinates P2 may be detected from the extracted binarized second image. The detected second coordinates P2 may be stored.

Next, the diameter R of the single-crystal ingot I is calculated based on the stored first coordinates P1 and second coordinates P2 (S150).

The embodiment may calculate the diameter of the single-crystal ingot in real time or at a preset time interval during growth of the single-crystal ingot via the second opening 310. In addition, the embodiment may acquire an image for clear identification of the boundary 401 between the melt M and the single-crystal ingot I owing to light emitted from the light source 210, which enables accurate extraction of the second coordinates P2 with respect to the boundary 401 and consequently, accurate calculation of the diameter of the single-crystal ingot I.

FIG. 9 shows an embodiment of a method of calculating the diameter R of the single-crystal ingot I shown in FIG. 6. Referring to FIG. 9, the diameter of the single-crystal ingot I may be calculated based on a difference between the first coordinates P1 and the second coordinates P2 (|P1-P2|).

The diameter R of the single-crystal ingot I may be calculated continuously or at a preset time interval during growth of the single-crystal ingot I because the embodiment may acquire the second image data ID2 and the second coordinates P2 continuously or at a preset time interval during growth of the single-crystal ingot I. Here, growth of the single-crystal ingot I may include necking, shouldering, and body processes of the single-crystal ingot I.

The controller 250 adjusts the growth rate of the single-crystal ingot I based on the diameter of the single-crystal ingot I provided from the detector 240. In this case, the growth rate of the single-crystal ingot I may be determined according to the diameter of the single-crystal ingot grown for a predetermined time.

The controller 250 may calculate the growth rate of the single-crystal ingot I based on the diameter of the single-crystal ingot I calculated by the detector 240, and adjust the temperature of the heater 130 as well as the rising velocity realized by the transfer unit 170 based on the calculated growth rate of the single-crystal ingot I.

For example, the controller 250 may calculate the growth rate of the single-crystal ingot I based on the diameter of the single-crystal ingot I that is provided continuously or at a preset time interval during growth of the single-crystal ingot I. In addition, the controller 250 may compare the calculated growth rate of the single-crystal ingot I with a preset growth rate, and adjust at least one of the rising velocity of the single-crystal ingot by the transfer unit 170 and the temperature of the heater 130 based on the comparison result.

For example, if the growth rate of the single-crystal ingot I is less than the preset growth rate, the controller 250 may lower the temperature of the heater 130 or reduce the rising velocity realized by the transfer unit 170. In addition, if the growth rate of the single-crystal ingot I is greater than the preset growth rate, the controller 250 may raise the temperature of the heater 130 or increase the rising velocity realized by the transfer unit 170.

The embodiment may adjust the growth rate of the single-crystal ingot I to suit to the preset growth rate based on the diameter of the single-crystal ingot that is calculated in real time or at a preset time interval for a single-crystal ingot growth period.

FIG. 3 shows a second embodiment 150-1 of the top insulator shown in FIG. 1.

Referring to FIG. 3, the top insulator 150-1 has the first opening 201 and a second opening 320. Differently from the embodiment shown in FIG. 2, the second opening 320 may reach both the inner circumferential surface 301 and the outer circumferential surface 302. In addition, the length L2 of the second opening 320 may be equal to the distance between the inner circumferential surface 301 and the outer circumferential surface 302. Other shapes, materials, and configurations of the top insulator may be equal to the above description of FIG. 2.

FIG. 4 shows a third embodiment 150-2 of the top insulator shown in FIG. 1.

Referring to FIG. 4, the top insulator 150-2 may have the first opening 201 and a second opening 330.

The second opening 330 may include a plurality of first sub-openings a1 to aN (N being a natural number greater than 1). The plurality of first sub-openings a1 to aN (for example, N=3) may be spaced apart from one another between the inner circumferential surface 301 and the outer circumferential surface 302, and a portion of the top insulator 150-2 may be interposed between the neighboring first sub-openings (for example, between a1 and a2 and between a2 and a3). The foremost first sub-opening a1 may come into contact with the first opening 201, and the last first sub-opening a3 may be spaced apart from the outer circumferential surface 302.

The plurality of first sub-openings a1 to aN (N being a natural number greater than 1) may respectively have various shapes including, e.g., square, circular, and elliptical shapes. The width of the plurality of first sub-openings a1 to aN (N being a natural number greater than 1) may be equal to the width of the second opening 310 as described above in FIG. 2.

Although the third embodiment cannot calculate the diameter of the single-crystal ingot in a section between the neighboring first sub-openings, the third embodiment may achieve enhanced thermal insulation because of a smaller area of the openings than in the first embodiment.

FIG. 5 shows a fourth embodiment 150-3 of the top insulator shown in FIG. 1.

Referring to FIG. 5, the fourth embodiment 150-3 may include a third opening 310-1, in addition to the first embodiment 150. In this case, the third opening 310-1 and the second opening 310 may be symmetrical to each other on the basis of the first opening 201.

In the first embodiment 150, insulation unbalance caused by the second opening 310 may cause eccentric growth of the single-crystal ingot. However, the fourth embodiment 150-3 may achieve balanced insulation through provision of the second opening 310 and the third opening 310-1 that are symmetrical to each other, thereby preventing eccentric growth of the single-crystal ingot.

FIG. 6 shows a fifth embodiment 150-4 of the top insulator shown in FIG. 1. Referring to FIG. 6, the fifth embodiment 150-4 may include a third opening 320-1, in addition to the second embodiment 150-2. In this case, the third opening 320-1 and the second opening 320 may be located symmetrical to each other on the basis of the first opening 201. The fifth embodiment 150-4 may prevent eccentric growth of the single-crystal ingot.

FIG. 7 shows a sixth embodiment 150-5 of the top insulator shown in FIG. 1. Referring to FIG. 7, the sixth embodiment 150-5 may include a third opening 330-1, in addition to the third embodiment 150-2. In this case, the third opening 330-1 and the second opening 330 may be located symmetrical to each other on the basis of the first opening 201. For example, the third opening 330-1 may include a plurality of second sub-openings b1 to bN (N being a natural number greater than 1). The second sub-openings b1 to bN (N being a natural number greater than 1) and the first sub-openings a1 to aN (N being a natural number greater than 1) may be symmetrical to each other on the basis of the first opening 201. The sixth embodiment 150-4 may prevent eccentric growth of the single-crystal ingot.

In the above-described fourth to sixth embodiments, the

second openings

310, 320 and 330 and the third openings 310-1, 320-1 and 330-1 may have the same shape and size, and may have symmetrical positions.

The above-described features, configurations, effects, and the like of the embodiments are included in at least one embodiment of the disclosure, and are not intended to be limited to any one embodiment. Moreover, the features, configurations, effects, and the like illustrated in the respective embodiments can be combined or modified in various ways by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. Accordingly, content related to these combinations and modifications must be construed as being within the scope of the disclosure.

A single-crystal ingot growth apparatus according to the embodiments may be utilized in a single-crystal ingot growth process.

Claims

A single-crystal ingot growth apparatus comprising:

a chamber;

a crucible placed within the chamber and configured to accommodate a melt that is a raw material for single-crystal growth;

a top insulator located at an upper end of the crucible, the top insulator having a central first opening and a second opening provided between an inner circumferential surface and an outer circumferential surface of the top insulator;

a camera configured to capture an image of the melt and a single-crystal ingot that is being grown, through the first opening and the second opening and to output image data; and

a detector configured to calculate a diameter of the single-crystal ingot that is being grown, based on the image data.
The apparatus according to claim 1, wherein the first opening takes the form of a circle having a predetermined diameter, and the second opening takes the form of a line having a predetermined length and width.
The apparatus according to claim 1, wherein the second opening originates from the first opening so as to extend between the inner circumferential surface and the outer circumferential surface.
The apparatus according to claim 1, wherein the second opening exposes a boundary between the melt and the single-crystal ingot that is being grown.
The apparatus according to claim 3, wherein the second opening is spaced apart from the outer circumferential surface.
The apparatus according to claim 3, wherein the second opening reaches both the inner circumferential surface and the outer circumferential surface.
The apparatus according to claim 2, wherein the second opening includes a plurality of first sub-openings, and the plurality of first sub-openings is spaced apart from one another between the inner circumferential surface and the outer circumferential surface.
The apparatus according to claim 3, wherein the top insulator further includes a third opening, and the third opening and the second opening are symmetrical to each other on the basis of the first opening.
The apparatus according to claim 7, wherein the top insulator further includes a third opening including a plurality of second sub-openings, and the first sub-openings and the second sub-openings are symmetrical to each other on the basis of the first opening.
The apparatus according to claim 1, wherein the top insulator includes:

a first insulator configured to reflect radiant heat generated from the melt into the crucible, the first insulator including a single layer; and

a second insulator placed over the first insulator, the second insulator including a stack of a plurality of layers, and

wherein each of the first insulator and the second insulator includes the first opening and the second opening.
The apparatus according to claim 1, further comprising a light source located at an upper end of the chamber and configured to emit light having a preset wavelength to the melt and the single-crystal ingot that is being grown, through the second opening.
A single-crystal ingot growth apparatus comprising:

a chamber;

a crucible placed within the chamber and configured to accommodate a melt that is a raw material for single-crystal growth;

a top insulator located at an upper end of the crucible, the top insulator having a central first opening and a second opening provided between an inner circumferential surface and an outer circumferential surface of the top insulator;

a camera configured to capture an image of the melt and a single-crystal ingot that is being grown, through the first opening and the second opening and to output image data;

a detector configured to calculate a diameter of the single-crystal ingot that is being grown, based on the image data; and

a controller configured to adjust a growth rate of the single-crystal ingot based on the calculated diameter of the single-crystal ingot.
The apparatus according to claim 12, further comprising a light source located at an upper end of the chamber and configured to emit light having a preset wavelength to the melt and the single-crystal ingot that is being grown, through the second opening.
The apparatus according to claim 13, wherein the preset wavelength is equal to or greater than 600nm and is equal to or less than 450nm.
The apparatus according to claim 13, wherein the camera outputs the image data based on the result captured in a state in which the light source emits light.
The apparatus according to claim 12, further comprising:

a heater provided between the crucible and the chamber to heat the crucible;

a seed connector to which a seed crystal is secured; and

a transfer unit configured to raise or lower the seed connector,

wherein the controller controls at least one of a temperature of the heater and a rising velocity realized by the transfer unit based on the calculated diameter of the single-crystal ingot.
The apparatus according to claim 16, wherein the camera captures an image through the first opening when the seed crystal comes into contact with a surface of the melt, and then outputs first image data based on the captured result, and the camera captures an image of a boundary between the single-crystal ingot that is being grown and the melt, through the second opening, and then outputs second image data based on the captured result.
The apparatus according to claim 17, wherein the second image data is output continuously or at a preset time interval during growth of the single-crystal ingot.
The apparatus according to claim 17, wherein the detector detects first coordinates based on the first image data and stores the detected first coordinates, and detects second coordinates based on the second image data and stores the detected second coordinates, thereby calculating the diameter of the single-crystal ingot based on the stored first coordinates and second coordinates.
The apparatus according to claim 19, wherein the diameter of the single-crystal ingot is calculated continuously or at a preset time interval during growth of the single-crystal ingot.