KR20190100653A - Method for correcting shape of silicon single crystal ingot - Google Patents

Abstract

An embodiment provides a method for correcting a shape of a silicon single crystal ingot, which comprises the steps of: growing a silicon single crystal ingot; comparing a shape of a tail portion of the grown silicon single crystal ingot with a target shape; and correcting the pulling speed of the silicon single crystal ingot when the shape of the tail portion does not match the target shape.

Description

Shape correction method of silicon single crystal ingot {METHOD FOR CORRECTING SHAPE OF SILICON SINGLE CRYSTAL INGOT}

The embodiment relates to a shape correction method of a silicon single crystal ingot, and more particularly, to a method of preventing pop out of a tail from silicon melt during tail growth of a silicon single crystal ingot.

Silicon wafer (wafer) used as a material for producing electronic components such as semiconductors or solar cells is a slicing process for thinly cutting single crystal silicon ingots in the form of wafers, and improves flatness while polishing to a desired wafer thickness. Lapping, etching to remove the damage layer inside the wafer, polishing to improve surface mirroring and flatness, cleaning to remove contaminants on the wafer surface Produced through steps such as cleaning.

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

In the Czochralski method, polycrystalline silicon is charged into a quartz crucible, heated and melted by a graphite heating element, and then immersed in a resultant melt of silicon, and the seed crystal is rotated and pulled while rotating when crystallization occurs at the interface. Grow the silicon ingot.

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.

At the end of growth of the body, a tail forming process may be performed in which the diameter of the silicon single crystal ingot gradually decreases. This tail forming process is to prevent pop out of the silicon single crystal ingot from the silicon melt remaining in the crucible (Si melt).

To this end, an observation sensor may be provided during the growth of the silicon single crystal ingot, or the diameter change may be indirectly monitored by parameters such as pulling speed and temperature, but the tail shape of the silicon single crystal ingot may not be directly observed. Is difficult to control and therefore may not be sufficient to prevent the pop out described above.

The embodiment is intended to solve the above-described problem, and to grow the tail portion in the same manner as the target condition during the growth of the silicon single crystal ingot, and in particular, to prevent the pop out of the ingot separating from the silicon melt of the crucible during the growth.

Embodiments include growing a silicon single crystal ingot; Comparing a shape of a tail portion of the grown silicon single crystal ingot with a target shape; And correcting the pulling speed of the silicon single crystal ingot when the shape of the tail portion does not match the target shape.

When the shape of the tail portion is larger than the target shape, the pulling speed of the silicon single crystal ingot may be increased.

The pulling speed of the corrected silicon single crystal ingot may be equal to the product of the pulling speed of the silicon single crystal ingot before the correction and a ratio in which the shape of the tail portion is larger than the target shape.

The shape correction method of the silicon single crystal ingot increases the temperature in the process chamber when the shape of the tail portion is larger than the target shape, or lowers the position of the crucible containing the silicon melt for growth of the silicon single crystal ingot. It may further comprise a step.

When the shape of the tail portion is smaller than the target shape, the crucible containing the silicon melt for growing the silicon single crystal ingot may be raised.

The positional impression of the crucible may be equal to the product of the pulling speed of the silicon single crystal ingot before the correction, the ratio of the shape of the tail portion smaller than the target shape, and the moving speed of the crucible.

The shape correction method of the silicon single crystal ingot may further include measuring the length of the tail portion when the shape of the tail portion of the grown silicon single crystal ingot is the same as the target shape.

Ingot cutting device and method according to the embodiment, in the growth of the silicon single crystal ingot, in particular, measuring the actual shape of the tail portion and compared with the target shape, if there is a mismatch, the tail portion is a target by changing the growth conditions as described above May be grown to be the same or similar to Therefore, in the tail forming process of the late growth stage of the silicon single crystal ingot, it is possible to prevent the pop out phenomenon in which the ingot suddenly splits from the crucible by adjusting the position of the crucible, the pulling speed of the ingot and the melt gap.

1 is a view showing the configuration of an embodiment of an ingot growth apparatus according to the embodiment,
Figure 2 is a view showing the shape of the silicon single crystal ingot grown in the apparatus of Figure 1,
3A is a view showing shapes of the tail portion of a silicon single crystal ingot,
3B is a diagram showing a relationship between a melt gap and a length of a tail portion during growth of a silicon single crystal ingot,
4 is a view showing an embodiment of a shape correction method of a silicon single crystal ingot,
5A to 5C show cases where the shape of the tail portion of the grown silicon single crystal ingot is larger than the target shape,
6A and 6B show cases where the shape of the tail portion of the grown silicon single crystal ingot is smaller than the target shape.

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.

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.

1 is a view showing the configuration of an embodiment of an ingot growth apparatus according to the embodiment.

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 growth apparatus 100 of a silicon single crystal ingot may include a chamber 100 in which a space for growing the silicon single crystal ingot 140 is formed from a silicon (Si) melt, and the silicon single crystal melt (Si melt) is accommodated therein. Crucibles (120, 122), the heating portion 140 for heating the crucibles (120, 122), and the crucible to block the heat of the heating portion 140 toward the silicon single crystal ingot 140 The crucible 122 is rotated by an upper heat insulating member 160 positioned above the 120, a seed chuck 180 for fixing the seed 185 for growth of the silicon single crystal ingot, and a driving means. It may be made by including a rotating shaft 130 to rotate to rise.

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.

2 is a view showing the shape of a silicon single crystal ingot grown in the apparatus of FIG.

Silicon single crystal ingots grown in the longitudinal direction from the seed side to the tail side may be cut into the transverse direction and manufactured into a plurality of wafers through a further processing process.

3A is a view showing shapes of the tail portion of the silicon single crystal ingot, and FIG. 3B is a view showing a relationship between the melt gap and the length of the tail portion during growth of the silicon single crystal ingot.

In FIG. 3, the length of the tail portion of the silicon single crystal ingot is longer in Example 2 and shorter in Example 3 than in Example 1. FIG. There are several factors that affect the length of the tail portion, but considering only the melt gap without considering other factors, the length of the tail portion may be relatively long when the melt gap is gradually increased.

The melt gap refers to a gap between the upper insulation member 160 of FIG. 1 and the silicon melt (Si melt), and as the melt gap gradually increases, as in Example 2 of FIG. 3B, the tail portion of the silicon single crystal ingot is increased. It can be interpreted that this can be sufficiently grown.

At this time, when the tail portion grows too short or too long at the time of growth of the silicon single crystal ingot, a method of correcting this is necessary.

4 is a diagram illustrating an embodiment of a shape correction method of a silicon single crystal ingot.

First, a silicon single crystal ingot is grown (S110). For example, a silicon single crystal ingot may be grown by the Czochralski method, in which the silicon single crystal ingot is grown after the neck, shoulder and body portions of the device are grown. The tail portion can be grown.

Upon growth of the tail portion, the shape of the tail portion may be compared with the target shape (S120). For example, the shape of the target portion may correspond to Example 1 of FIG. 3A, and the contour of the tail portion as well as the length of the tail portion may be compared with the entire target portion in the above-described comparison step.

5A to 5C show cases where the shape of the tail portion of the grown silicon single crystal ingot is larger than the target shape.

In FIG. 5A, the target shape of the length of the tail portion in the radial direction of the silicon single crystal ingot is shown by the solid line, and the shape of the tail portion of the silicon single crystal ingot which is actually growing is shown by the dotted line. This shape may be the same as those of FIGS. 5B and 5C when the measurement is performed by the imaging device, and may be a case where the pulling speed of the silicon single crystal ingot is slow or the melt gap is too large.

6A and 6B show cases where the shape of the tail portion of the grown silicon single crystal ingot is smaller than the target shape.

In FIG. 6A, the target shape of the length of the tail portion in the radial direction of the silicon single crystal ingot is shown by the solid line, and the shape of the tail portion of the silicon single crystal ingot which is actually growing is shown by the dotted line. This shape may be as shown in FIG. 6B when the actual measurement is performed by the imaging device, and the pulling speed of the silicon single crystal ingot may be high or the melt gap may be too small.

It is determined whether the shape of the tail portion matches the target shape (S130), and if it matches (Yes), it is determined whether the length of the tail portion is the same as the preset value (S140). That is, if the shape of the tail portion matches the target shape, the tail portion is grown to a predetermined length. For example, if the length of the tail portion is set to 150 millimeters in advance, the length of the tail portion actually measured is 150 millimeters. Yes, the growth of silicon single crystal ingots can be terminated.

In operation S140, when the length of the tail portion of the silicon single crystal ingot does not reach a predetermined value (No), the silicon single crystal ingot, particularly the tail portion, may be continuously grown (S110).

In the above step S130, if the shape of the tail portion does not match the target shape (No), the magnitude of the actual shape (A) and the target shape (T) of the tail portion is compared (S150), and the tail according to the result The shape correction method of the part is different.

That is, when the actual shape A of the tail portion is larger than the target shape T (Yes), correction (S160) of reducing the shape or size of the tail portion may be performed. This case may correspond to FIGS. 5A to 5C.

In detail, the pulling speed of the silicon single crystal ingot can be increased. At this time, the pulling speed of the silicon single crystal ingot can be corrected as in Equation 1 below.

<Equation 1>

PS = Error × A_P / S

Here, PS is the pulling speed of the silicon single crystal ingot after correction, A_P / S is the pulling speed of the silicon single crystal ingot measured before the correction, Error may be the degree of the tail portion is out of the target shape, in this embodiment the tail The shape of the portion may be a larger ratio (eg, 1, 2, 1, 3, etc.) than the shape of the target portion.

In addition to increasing the pulling speed of the silicon single crystal ingot described above, the temperature in the process chamber may be increased or the crucible containing the silicon melt for growth of the silicon single crystal ingot may be lowered.

The correction methods described above can act similar to increasing the melt gap in the growth apparatus of silicon single crystal ingots.

When the actual shape A of the tail portion is smaller than the target shape T (No), correction (S170) of increasing the shape or size of the tail portion may be performed. This case may correspond to FIGS. 6A to 6B.

In detail, it is possible to raise the position of the crucible containing the silicon melt for the growth of the silicon single crystal ingot. At this time, the position increase of the crucible may be as shown in Equation 2 below.

<Equation 2>

CL = -Error X CLR X A_P / S

Here, A_PS is the pulling speed of the silicon single crystal ingot measured before correction, Error is the ratio of the shape of the tail portion is smaller than the target shape, CLR may be the moving speed of the crucible, and (-) sign is the grown silicon single crystal The tail of the ingot has grown smaller than the target.

When the silicon single crystal ingot is grown through the above-described method, in particular, the actual shape of the tail portion is measured only in length and appearance and compared with the target shape. If there is a mismatch, the tail portion is the same as the target by varying the growth conditions as described above. Or similar growth. Therefore, in the tail forming process of the late growth stage of the silicon single crystal ingot, it is possible to prevent the pop out phenomenon in which the ingot suddenly splits from the crucible by adjusting the position of the crucible, the pulling speed of the ingot and the melt gap.

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.

100: growth device of silicon single crystal ingot
110: chamber 120, 122: crucible
130: rotating shaft 140: heating
160: upward insulation member 180: seed chuck
185: seed chuck 190: water cooling tube

Claims (7)

Growing a silicon single crystal ingot;
Comparing a shape of a tail portion of the grown silicon single crystal ingot with a target shape; And
Correcting the pulling speed of the silicon single crystal ingot when the shape of the tail portion is inconsistent with the target shape. According to claim 1,
And the pulling speed of the silicon single crystal ingot is increased when the shape of the tail portion is larger than the target shape. The method of claim 2,
And the pulling speed of the corrected silicon single crystal ingot is equal to the product of the pulling speed of the silicon single crystal ingot before correction and the ratio of the shape of the tail portion is larger than the target shape. The method according to claim 2 or 3,
If the shape of the tail portion is larger than the target shape, increasing the temperature in the process chamber or lowering the location of the crucible containing the silicon melt for growth of the silicon single crystal ingot; Shape correction method of ingot. According to claim 1,
When the shape of the tail portion is smaller than the target shape, the shape correction method of the silicon single crystal ingot to raise the position of the crucible containing the silicon melt for the growth of the silicon single crystal ingot. The method of claim 5,
The position raising part of the said crucible is the shape correction method of the silicon single crystal ingot same as the product of the pulling speed of the silicon single crystal ingot before the said correction, the shape of the said tail part is smaller than the said target shape, and the moving speed of the said crucible. According to claim 1,
And measuring the length of the tail portion when the shape of a tail portion of the grown silicon single crystal ingot is the same as the target shape.

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