WO2017111227A1

WO2017111227A1 - Growth device and growth method of silicon monocrystalline ingot

Info

Publication number: WO2017111227A1
Application number: PCT/KR2016/006748
Authority: WO
Inventors: 김정열; 김세훈; 김윤구
Original assignee: 주식회사 엘지실트론
Priority date: 2015-12-23
Filing date: 2016-06-24
Publication date: 2017-06-29
Also published as: KR101841550B1; KR20170075280A

Abstract

An embodiment provides a growth method of a silicon monocrystalline ingot, comprising the steps of: dipping a seed in a silicon melt; (a) measuring a surface temperature of the silicon melt; (b) measuring a melting shape of the seed on the surface of the silicon melt; and raising the seed when good dipping is determined from the surface temperature and the melting shape.

Description

Growth device and growth method of silicon single crystal ingot

Embodiments relate to an apparatus and method for growing silicon single crystal ingots, and more particularly, to an apparatus and method for accurately determining good dipping of seeds for growth of silicon single crystal ingots.

The silicon wafer has a single crystal growth process for producing a single crystal ingot, a slicing process for slicing the single crystal ingot to obtain a thin disk-shaped wafer, and a crack and distortion of the wafer obtained by the slicing process. Grinding process for processing the outer periphery thereof, lapping process for removing damage due to mechanical processing remaining on the wafer, polishing process for mirror- mirroring the wafer, and polishing And a cleaning process for polishing the wafer and removing foreign matter or foreign matter adhering to the wafer.

The silicon single crystal ingot thus grown is used as the substrate of the semiconductor device through the above-described process.

The growth of silicon single crystal ingots has been widely used by the floating zone (FZ) method or the Czochralski (CZ, hereinafter CZ) method. The most common of these methods is the CZ method.

In the CZ method, polycrystalline silicon is charged into a quartz crucible, heated and melted by a graphite heating element, and then immersed the seed crystals in the resulting silicon melt, and when the crystallization occurs at the interface, the single crystal silicon ingot is rotated and pulled up. To grow.

Specifically, the crucible is raised while rotating the shaft supporting the crucible so that the solid-liquid interface maintains the same height, and the silicon single crystal ingot is pulled while rotating in the direction opposite to the rotation direction of the crucible about the same axis as the rotation axis of the crucible. Up.

Processes for growing silicon single crystal ingots include dipping of seeds and growing necks, shoulders, and bodies. After seeding the seed crystals into the silicon melt and determining that the temperature of the silicon melt is within a certain range as good dipping, the seed crystals may be raised to grow a silicon single crystal ingot.

Determination of good dipping is important in the growth of silicon single crystal ingots, and FIG. 1 is a view illustrating a method of determining good dipping of seeds of a conventional silicon single crystal ingot.

The temperature sensor 10 determines the good dipping by measuring the temperature of the meniscus region around the seed. The part where the seed melts appears brighter than the surroundings, and as shown, the shape of the boundary region where the seed melts at the edge of the seed may be referred to as a meniscus. In fact, the melting region of the seed may form a closed curved surface, but may be observed by being partially shielded by the upper region of the unmelted seed when photographing by the temperature sensor 10.

When the seed is melting as shown, the temperature may be raised by measuring the heat radiated from the silicon melt in the temperature sensor 10 to sense the surface temperature of the melt to reach a temperature that is good dipping.

2 is a view showing the temperature of the silicon melt with time in the method of FIG. As the dipping time increases, the temperature t0 of the silicon melt may converge within a predetermined range t1 to t2, and this may be determined as good dipping and the seed may be raised.

However, the conventional good dipping judgment has the following problems.

The center region of the silicon melt is the region where the seeds are dipped and melted, making it difficult to accurately measure temperature. In addition, the growth of the silicon single crystal ingot also involves the temperature in the chamber in addition to the temperature of the silicon melt, the above-described method is difficult to determine the temperature in the chamber.

In addition, the change of the heat distribution according to the flow of inert gas, such as argon, in a chamber cannot be measured.

3A to 3D are diagrams illustrating an error of a good dipping judgment in the conventional method. 3A to 3D show good dipping by the above-described method in the same growth apparatus, respectively, to raise the seed to start necking.

However, even if good dipping is determined by the same method using the same growth apparatus in FIGS. 3A to 3D, the time taken to grow the neck even if the temperatures determined to be good dipping are different from each other and are determined to be good dipping at the same temperature. These are different from each other.

This difference is due to the fact that the temperature sensor 10 alone does not identify various factors involved in the growth of the silicon single crystal ingot as described above, that is, it is difficult to accurately identify the good dipping of the seeds only by the temperature of the silicon melt surface. .

Embodiments provide an apparatus and method for accurately determining good dipping of seeds upon growth of silicon single crystal ingots.

Embodiments include dipping a seed in a silicon melt; (A) measuring the surface temperature of the silicon melt; (B) measuring a melting shape of the seed at the surface of the silicon melt; And pulling the seed when good dipping is determined from the surface temperature and the melting shape.

Step (a) may measure the surface temperature of the silicon melt using a temperature sensor.

In step (b), the shape of the melting region of the seed may be determined by the image sensor.

In step (b), when the length of one side of the melting region of the seed is greater than or equal to a predetermined length, it can be regarded as an effective shape.

When one side of the melting region of the seed is located within 1 degree (°) at a predetermined angle, it can be regarded as an effective shape.

In step (b), at least three shape factors of the seed melting region may be identified.

The radius of curvature of at least two vertex regions of the seed melting region can be understood as the first shape factor.

The radius of curvature of the two vertex areas can be averaged to determine the first shape factor.

The thickness of at least one side of the seed melting region can be understood as the second shape factor.

The curvature of at least one side of a seed melting region can be grasped | ascertained by a 3rd shape factor.

One side arrange | positioned between two vertex areas can grasp | ascertain curvature as a 3rd shape factor.

The melting shape of the seed may be asymmetric in the left and right directions.

Among the melting shapes of the seed, the three shape factors can be grasped only by the shape of the lower region.

Another embodiment includes a chamber; A crucible provided inside the chamber and containing a silicon melt; A heating unit provided inside the chamber and heating the silicon melt; An upper heat insulating member disposed above the crucible and shielding heat of the heating portion facing the single crystal ingot grown from the silicon melt; A temperature sensor disposed in a first region of the upper portion of the chamber to measure a surface temperature of the silicon melt; And an image sensor disposed in a second region of the upper portion of the chamber to measure a surface image of the silicon melt.

The controller may further include a controller configured to determine whether the seed is good dipped from the data measured by the temperature sensor and the image sensor.

An apparatus and a growth method of a silicon single crystal ingot according to an embodiment, when the seed is dipped and melted, the good dipping is identified from three shape factors of the meniscus, which is the shape of the melt region of the seed from the image sensor, and is identified from the temperature sensor. Used with the results, it is possible to pinpoint the growth point of the neck.

1 is a view showing a method for determining the good dipping of the seed of a conventional silicon single crystal ingot,

2 is a view showing the temperature of the silicon melt with time in the method of Figure 1,

3A to 3D are diagrams showing an error of a good dipping judgment in a conventional method,

4 is a view showing an embodiment of a device for growing a silicon single crystal ingot,

5a and 5b is a view showing the rotation of the meniscus shape according to the rotation of the seed,

5C and 5D show image extraction of seeds,

6A to 6D are diagrams illustrating a process of extracting features from the shape of a meniscus,

7 is a view showing the temperature and scoring of the silicon melt over time,

8 is a view showing a method of growing a silicon single crystal ingot according to the embodiment.

Hereinafter, the present invention will be described in detail with reference to the following examples, and the present invention will be described in detail with reference to the accompanying drawings.

However, embodiments according to the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

In the description of the embodiment according to the present invention, when described as being formed on the "on" or "on" (under) of each element, the upper (up) or the lower (down) (on or under) includes both the two elements are in direct contact with each other (directly) or one or more other elements are formed indirectly formed (indirectly) between the two elements.

In addition, when expressed as "up" or "on (under)", it may include the meaning of the downward direction as well as the upward direction based on one element.

Also, the relational terms used below, such as "first" and "second," "upper" and "lower", etc., do not necessarily require or imply any physical or logical relationship or order between such entities or elements. It may be used only to distinguish one entity or element from another entity or element.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

The silicon single crystal growth apparatus 100 according to the present exemplary embodiment may grow a silicon single crystal ingot by melting solid silicon to make a liquid and recrystallizing the same.

The apparatus for growing a silicon single crystal ingot includes a chamber 100 in which a space for growing the silicon single crystal ingot 140 is formed from a silicon (Si) melt and a crucible 120 for accommodating the silicon single crystal melt. , 122), a heating part 140 for heating the

crucibles

120 and 122, and a heat of the heating part 140 toward the silicon single crystal ingot 140, The upper heat insulating member 160 positioned upward, the seed chuck 180 for fixing the seed 185 for growth of the silicon single crystal ingot 140, and the crucible 122 rotated by the driving means. A temperature sensor 10 provided at the upper portion of the rotating shaft 130 and the chamber 110 to measure the surface temperature of the silicon melt Si, and a surface image of the silicon melt Si provided at the top of the chamber. It comprises an image sensor 20 to measure .

The chamber 110 may have a cylindrical shape having a cavity formed therein, and the

crucibles

120 and 122 are positioned in a central region of the chamber 110. The

crucibles

120 and 122 are in the shape of a concave bowl as a whole to accommodate the silicon single crystal melt, and may be made of a material such as tungsten (W) or molybdenum (Mo), but is not limited thereto.

The crucible may be formed of a quartz crucible 120 directly contacting the silicon single crystal melt and a graphite crucible 122 supporting the quartz crucible 120 while surrounding the outer surface of the quartz crucible 120.

In addition, a water cooling tube 190 may be provided on the grown silicon single crystal ingot 140 to cool the silicon single crystal ingot 140.

Hereinafter, an embodiment of the growth method of growth of silicon single crystal using the growth device of silicon single crystal described above will be described.

First, the silicon melt Si is filled into the crucible 120, and the seeds 185 are contacted with the silicon melt Si to be probed and dipping.

In addition, a portion of the seed may melt while the seed 185 is immersed in a high temperature silicon melt (Si).

Then, by using the temperature sensor 10 and the image sensor 20, whether or not good dipping is checked. Determination of the good dipping, (a) measuring the surface temperature of the silicon melt (Si) using the temperature sensor 10, and (b) measuring the shape of the seed melt on the surface of the silicon melt (Si) A) step is achieved.

The temperature sensor 10 determines the good dipping by measuring the temperature of the meniscus region around the seed. The part where the seed melts appears brighter than the surroundings, and as shown, the shape of the boundary region where the seed melts at the edge of the seed can be referred to as a meniscus, and the temperature sensor 10 measures the heat radiated from the silicon melt. The surface temperature of the melt can be detected.

In addition, the image sensor 20 may determine the good dipping by capturing the melted shape of the seed and analyzing the image captured by the controller (not shown). At this time, since the seed rotates, it is necessary to extract only valid data from the melting shape of the seed photographed by the image sensor 20.

That is, during the growth of the silicon single crystal ingot, the seeds and the crucibles 20 and 22 may rotate, respectively, and are referred to as seed rotation and crucible rotation, respectively. This can be in different directions.

5A and 5B are diagrams illustrating the rotation of the meniscus shape according to the rotation of the seed.

The shape of the meniscus at the edge is obtained by photographing the continuously rotating seeds, and the uppermost part in FIG. 5A and the lowermost part in FIG. 5B may be effective shapes. Here, the effective shape means a melting shape of the seed that can be effectively used to determine the good dipping.

That is, in order to grasp | ascertain three factors mentioned later, it is preferable that the melting shape of a seed is image | photographed like the uppermost part of FIG. 5A or the lowermost part of FIG. 5B.

5C and 5D illustrate image extraction of the seed. In FIG. 5C, one face of the meniscus, which is a melting region of the seed, overlaps the predetermined length d1 or more. In FIG. 5D, one face of the meniscus is preset length d1 according to the rotation of the seed. Overlap in areas smaller than). In this case, the case of FIG. 5C may be regarded as valid data, and FIG. 5D may be determined to be inappropriate data for determining good dipping.

The determination of whether the good dipping is described above may be determined by the length of the region where the meniscus overlaps with the preset length d1 as shown in FIG. 5A, but the degree of the shape of the meniscus is inclined at a predetermined angle. It may be determined, or may be regarded as valid data, for example, when it is located in an angle range within 1 degree (°).

6A to 6D are diagrams illustrating a process of extracting features from the shape of a meniscus.

In determining the melting shape of the seed, it can be determined from a plurality of factors, and in this embodiment, it can be grasped from three factors of the seed melting region. In FIG. 6A, the shapes of two vertex regions a1 and a2 and one side b region of the melt region of the seed may be determined from the photographed data.

The first shape factor may be the radius of curvature R1, R2 of the two vertex regions of the seed melting region, as shown in FIG. 6B. In this case, since the shape of the vertices of the seed melting region may not exactly form a circle, the radius of curvature R1 and R2 of the most similar circle may be calculated. The radiuses of curvature R1 and R2 of the two vertex areas measured and calculated can be averaged to determine the first shape factor.

As illustrated in FIG. 6C, the thickness t of at least one side of the seed melting region may be understood as the second shape factor.

In this case, as illustrated in FIG. 6C, the thickness t of the center region of the left and right sides of the shape of the melt region of the seed may be measured.

And as shown in FIG. 6D, the curvature R3 of the at least 1 side of a seed melting region can be grasped | ascertained as a 3rd shape factor. As shown, since one side of the seed melting region may not be exactly a circle, the curvature R3 of the most similar circle can be calculated.

6B-6D, the regions 1/2 of the left / right of the meniscus, which are the melt regions of the seed, may not be exactly symmetrical, with two radii of curvature R1, R2 and one curvature R3. When calculating the and thickness t, it can be determined only by the lower (2/5) h of the height of the meniscus.

When the seed is determined to be good dipping from the three shape factors of the above-described melt shape of the seed, and also determined to be good dipping from the surface temperature, the seed may be raised and the neck may be grown.

At this time, a portion of the silicon melt (Si) is solidified to grow a thicker neck than the seed.

In addition, the silicon melt (Si) is solidified and a single crystal is continuously grown from the lower part of the neck to form a shoulder. The shoulder is grown in a radial and vertical direction to increase the diameter of the single crystal and to immerse it into the silicon melt.

Then, as the silicon melt solidifies, a body may be continuously grown from the bottom of the shoulder. The interface between the silicon melt (Si) and the grown silicon single crystal ingot is also referred to as a growth interface (Crystallization Front).

8 shows a method of growing a silicon single crystal ingot according to the above-described embodiment.

FIG. 7 shows the temperature and scoring of a silicon melt over time. FIG.

In this case, the values of the three shape factors may be calculated as +1 or -1, respectively, depending on whether or not the values of the three shape factors meet predetermined requirements, and the values determined from the three shape factors may be distributed from +3 to -3.

a represents the surface temperature of the silicon melt measured by the temperature sensor, b is a value obtained by averaging the value of a every 5 minutes, c is a value determined from the three factors described above, and d is an average of c at regular intervals. One value.

In FIG. 7, as time elapses, the values of b and d are stable, and it may be determined that good dipping is performed.

An apparatus and a method for growing a silicon single crystal ingot according to an embodiment, as the seed is dipped and melted, identify a good dipping from three shape factors of the meniscus, which is the shape of the melt region of the seed from an image sensor, and is identified from a temperature sensor. Used with the results, it is possible to pinpoint the growth point of the neck.

As described above, although the embodiments have been described by the limited embodiments and the drawings, the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

In the growth apparatus and growth method of the silicon single crystal ingot according to the embodiment, it is possible to accurately determine the growth point of the neck through the temperature sensor and the image sensor.

Claims

Dipping the seeds in the silicon melt;

(A) measuring the surface temperature of the silicon melt;

(B) measuring a melting shape of the seed at the surface of the silicon melt; And

And when the good dipping is determined from the surface temperature and the melting shape, pulling up the seed.
The method of claim 1,

In the step (a), the silicon single crystal ingot growth method of measuring the surface temperature of the silicon melt in a temperature sensor.
The method of claim 1,

In the step (b), the silicon single crystal ingot growth method for determining the shape of the melting region of the seed in the image sensor.
The method of claim 3, wherein in step (b),

A method for growing a silicon single crystal ingot, which is regarded as an effective shape when the length of one side of the melt region of the seed is equal to or larger than a predetermined length.
The method of claim 4, wherein

A method for growing a silicon single crystal ingot, wherein one side of the melt region of the seed is located within 1 degree (°) of a predetermined angle to be regarded as an effective shape.
The method of claim 3, wherein in step (b),

A method for growing a silicon single crystal ingot that grasps at least three shape factors of the seed melting region.
The method of claim 6,

And a radius of curvature of at least two vertex regions of said seed melting region as a first shape factor.
The method of claim 7, wherein

A method of growing a silicon single crystal ingot, averaging the radius of curvature of the two vertex regions as the first shape factor.
The method of claim 6,

A method for growing a silicon single crystal ingot that grasps the thickness of at least one side of the seed melting region as a second shape factor.
The method of claim 6,

A method for growing a silicon single crystal ingot which grasps the curvature of at least one side of the seed melting region as a third shape factor.
The method of claim 10,

A method for growing a silicon single crystal ingot in which one side disposed between the two vertex regions is regarded as a third shape factor of curvature.
The method of claim 6,

Melting shape of the seed is a method of growing a silicon single crystal ingot asymmetric in the left and right direction.
The method of claim 6,

A method for growing a silicon single crystal ingot that grasps the three shape factors only by the shape of the lower region of the melt shape of the seed.
chamber;

A crucible provided inside the chamber and containing a silicon melt;

A heating unit provided inside the chamber and heating the silicon melt;

An upper heat insulating member disposed above the crucible and shielding heat of the heating portion facing the single crystal ingot grown from the silicon melt;

A temperature sensor disposed in a first region of the upper portion of the chamber to measure a surface temperature of the silicon melt; And

And an image sensor disposed in a second region of the upper portion of the chamber to measure a surface image of the silicon melt.
The method of claim 14,

The growth apparatus of the silicon single crystal ingot further comprises a control unit for determining whether the seed is good dipping from the data measured by the temperature sensor and the image sensor.
The method of claim 14, wherein the control unit,

An apparatus for growing a silicon single crystal ingot, which grasps an effective shape when the length of one side of the melt region of the seed is equal to or greater than a predetermined length.
The method of claim 14, wherein the control unit,

An apparatus for growing a silicon single crystal ingot, which grasps an effective shape when one side of the melt region of the seed is located within 1 degree (°) from a predetermined angle.
The method of claim 14, wherein the control unit,

And growing the radius of curvature of at least two vertex regions of said seed melting region as a first shape factor.
The method of claim 14, wherein the control unit,

A silicon single crystal ingot growth apparatus for grasping the thickness of at least one side of the seed melting region as a second shape factor.
The method of claim 14, wherein the control unit,

A silicon single crystal ingot growth apparatus for grasping the curvature of at least one side of said seed melting region as a third shape factor.