KR101540863B1 - Apparatus for controlling diameter of single crystal ingot and Ingot growing apparatus having the same and method thereof - Google Patents

Abstract

The ingot diameter control apparatus of the present invention is an ingot diameter control apparatus for controlling an ingot growing apparatus for pulling up an ingot from a silicon melt contained in a quartz crucible using a seed, comprising: a lifting means control unit for controlling the pulling speed of the seed; And a direct controller which receives a measurement value of a melt gap, which is a distance between the silicon melt and the heat shield, from the ingot growing apparatus, and controls the rotation and elevation speed of the quartz crucible in accordance with the melt gap measurement value. Wherein the direct controller receives the diameter measurement value of the ingot from the ingot growing apparatus, corrects the diameter measurement value in accordance with the melt gap measurement value, and outputs the corrected diameter measurement value to the lifting means control unit .
According to the present invention, there is an advantage that the ingot diameter can be uniformly maintained without any variation by predicting the change in the diameter of the ingot in advance and controlling the pulling speed of the ingot.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ingot diameter control apparatus and an ingot growing apparatus including the ingot diameter controlling apparatus,

The present invention relates to an apparatus for controlling the diameter of a single crystal ingot, an ingot growing apparatus including the same, and a method thereof.

Generally, CZochralski (hereinafter referred to as CZ) method is widely used as a method of manufacturing silicon wafers. In the CZ method, polycrystalline silicon is charged in a quartz crucible and heated by a graphite heating element to melt, The seed crystal is immersed in the formed silicon melt and the crystallization is caused at the interface, and the seed crystal is pulled while rotating to start the ingot growth.

At the initial stage of pulling, the neck portion of the ingot is necked with a thin diameter to remove a dislocation generated in the ingot, and then the shoulder portion is shouldered to enlarge the diameter of the crystal.

Thereafter, a body growing process is performed in which a body of the ingot is grown by growing a single crystal having a constant diameter. At this time, whether or not the diameter of the formed body is uniform is an important factor for determining the quality of the ingot.

Conventionally, in order to keep the diameter of the ingot uniform, the diameter of the body to be grown is measured in real time, and when the measured current diameter is different from the target diameter, the pulling speed V of the ingot is controlled, And the method of reducing the error of the target diameter was used.

Meanwhile, vacancies and interstitial silicon flow into the single crystal through the solid-liquid interface when the single crystal ingot is grown by the CZ method. And, when the concentration of vacancies and interstitials introduced into the single crystal reaches the supersaturated state, the vacancies and the interstitial silicon diffuse and aggregate to form vacancy defects (hereinafter referred to as V defects) and interstitial defects ).

These V defects and I defects adversely affect the characteristics of the wafers produced from the ingot, so that the formation of V defects and I defects must be suppressed as much as possible during single crystal growth.

Generally, in order to suppress the occurrence of V defects and I defects, a method of controlling the V / G, which is the ratio between the pulling rate V of the single crystal and the temperature gradient G at the liquid interface, is controlled within a specific range, Is controlled by changing the melt gap, which is the distance between the shield and the silicon melt.

However, if the pulling speed of the ingot is changed by the diameter of the ingot measured as described above, the melt gap is also changed. Further, when the melt gap is changed, the crucible lifting speed is corrected to reduce the change in the melt gap, and the diameter of the ingot again changes with the change in the crucible lifting speed.

That is, if the crucible lifting speed is controlled to control the changed melt gap, a fluctuation occurs in the diameter of the ingot.

Eventually, the fluctuation of the diameter increases due to the fluctuation of the diameter, and the quality of the ingot deteriorates.

The present invention has been made in order to solve the above problems and it is an object of the present invention to provide a single crystal ingot diameter control device capable of uniformly controlling the diameter of the ingot by controlling the pulling speed of the ingot in consideration of the melt gap measured in real time And an apparatus including the same.

The ingot diameter control apparatus of the present invention is an ingot diameter control apparatus for controlling an ingot growing apparatus for pulling up an ingot from a silicon melt contained in a quartz crucible using a seed, comprising: a lifting means control unit for controlling the pulling speed of the seed; And a direct controller which receives a measurement value of a melt gap, which is a distance between the silicon melt and the heat shield, from the ingot growing apparatus, and controls the rotation and elevation speed of the quartz crucible in accordance with the melt gap measurement value. Wherein the direct controller receives the diameter measurement value of the ingot from the ingot growing apparatus, corrects the diameter measurement value in accordance with the melt gap measurement value, and outputs the corrected diameter measurement value to the lifting means control unit .

Further, the ingot growing apparatus of the present invention comprises: a quartz crucible for accommodating a silicon melt; A seed chuck for fixing the seed for pulling the ingot starting from the silicon melt; A seed lifting means for lifting the seed chuck by immersing the seed chuck in the silicon melt and lifting the ingot while rotating the seed chuck; A heat shield forming a melt gap as a heat insulating means on the upper portion of the silicon melt; A diameter measuring sensor for measuring the diameter of the ingot being pulled up; A melt gap measurement sensor for measuring the melt gap; A pull-up means control unit for controlling pull-up speed for pulling up the seed; And a direct controller that receives the melt gap measurement value from the melt gap measurement sensor and adjusts the rotation and elevation speed of the quartz crucible. Wherein the direct controller receives a diameter measurement value from the diameter measurement sensor, corrects the diameter measurement value in accordance with the melt gap measurement value, and transmits the corrected diameter measurement value to the lifting means control unit .

In addition, the ingot growing method of the present invention includes the steps of: starting the ingot growing step and measuring the diameter of the melt gap and the ingot to be grown, which is the distance between the heat shield and the surface of the silicon melt contained in the quartz crucible, Calculating a difference between the measured current melt gap and a preset target melt gap value to a target value; Changing the elevation speed of the quartz crucible when the difference is out of a predetermined allowable range and calculating a diameter correction value according to the current melt gap; Calculating a corrected diameter measurement value by correcting the current diameter measurement value to the diameter correction value; Controlling the pulling speed of the ingot to the corrected diameter measurement value; And a control unit.

The present embodiment is advantageous in that the ingot can be produced in the defect-free region by accurately controlling the temperature gradient G by maintaining the target melt gap through measurement of the melt gap in real time.

Further, when the crucible lifting speed is changed for controlling the melt gap, the diameter change of the ingot is predicted in advance, and the pulling speed of the ingot is controlled so that the diameter of the ingot can be uniformly maintained without any deviation.

1 shows a schematic view of an ingot growing apparatus according to an embodiment of the present invention.
FIG. 2 is a graph illustrating actual measured ADC values and corrected ADC values according to an embodiment of the present invention. FIG.
Figure 3 shows a target diameter correction value (Dia. Target Scheduler) for correcting an actually measured ADC value according to an embodiment of the present invention.
4 is a schematic block diagram of an ingot growing apparatus according to another embodiment of the present invention.
5 is a flow chart for crucible lifting speed and lifting speed control according to another embodiment of the present invention.
6 shows a real-time diameter correction value according to the crucible lifting speed change according to another embodiment of the present invention.
Figure 7 is a graph of real-time ADC correction values calculated from a target diameter correction value (dia. Target scheduler) of an embodiment of the present invention and a measured melt gap of another embodiment of the present invention.

Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. It should be understood, however, that the scope of the inventive concept of the present embodiment can be determined from the matters disclosed in the present embodiment, and the spirit of the present invention possessed by the present embodiment is not limited to the embodiments in which addition, Variations.

<Embodiment>

1 shows a schematic view of an ingot growing apparatus according to an embodiment of the present invention.

1, the ingot growing apparatus of the present embodiment includes a chamber 10, a quartz crucible 20 for containing a silicon melt, a heater 40 for transferring heat energy to the quartz crucible 20, A heat shield 50 for forming a melt gap as a heat insulating means on the silicon melt, a seed chuck 60 for fixing a seed contained in the silicon melt for lifting an ingot, And a pulling system 400 for rotating and lifting the seed chuck 60 through a pull cable connected to the chuck 60 to grow an ingot.

Further, the ingot growing apparatus of this embodiment includes a view port disposed at one side of the chamber 10 for observing the inside of the chamber 10 which is hermetically sealed, and a diameter measuring sensor for measuring the diameter of the ingot growing through the view port (300).

The diameter measuring sensor 300 is a sensor for measuring the diameter of the ingot and outputting it as raw data. Various sensors such as an IR sensor, a CCD camera or a pyrometer may be used, It is not.

The data measured by the diameter measuring sensor 300 is transmitted to the pulling rate controller 350. The pulling rate controller 350 analyzes the data and converts the data into data indicating the diameter of the ingot, And compared with the target diameter data.

When the measured data and the target diameter data are different from each other, the pulling rate control unit 350 changes the pulling speed by controlling the pulling means 400 to reduce the difference between the measured data and the target diameter data By repeating the process, the diameter of the ingot can be controlled to be constant.

In the present embodiment, an ADC sensor (Automatic Diameter Control) is used for the diameter measuring sensor 300 and the pulling-up speed controller 350. The ADC sensor measures the brightness of the meniscus of the ingot to be grown, converts the diameter of the ingot into the ADC value, and controls the pulling speed by comparing the predetermined target ADC value with the measured current ADC value, This corresponds to a sensor for controlling the diameter of the ingot.

In the following description, the diameter measurement sensor 300 and the pull-up speed control unit 350 will be described as an ADC sensor for convenience, but the present invention is not limited thereto.

A quartz crucible 20 in which a silicon melt is accommodated as a hot zone structure is disposed in the chamber 10 and a crucible support 30 for supporting the load of the quartz crucible 20, 120 are coupled to the lower portion of the quartz crucible 20. [ The pedestal 120 is connected to the crucible lifting means 100 through the crucible supporting shaft 110 so that the quartz crucible 20 can be lifted and lowered by the crucible lifting means 100.

The melt gap sensor 200 for measuring a melt gap (hereinafter referred to as "M / G" for convenience), which is a distance between the silicon melt and the heat shield 50, is provided in the ingot growing apparatus of this embodiment And a lift unit driving unit 150 for controlling the crucible elevating unit 100 by comparing the measured melt gap with the target melt gap.

That is, since the melt gap is changed according to the ascending / descending speed of the quartz crucible 20, the melt gap sensor 200 measures the melt gap in real time and transmits the measured melt gap to the lift unit driving unit 150, The elevating device driving unit 150 controls the crucible elevating means 100 by comparing the measured melt gap with a target melt gap (target M / G) which is a predetermined target value. As described above, since the melt gap affects the temperature gradient G, the measured melt gap is maintained at a designed melt gap value according to the length of the ingot to prevent crystal defects of the ingot from being generated.

However, when the crucible lifting means 100 changes the crucible lifting speed, not only the melt gap but also the diameter of the ingot are changed.

More specifically, since the diameter of the ingot is influenced by the pulling speed of the seed chuck 60 and the speed of raising and lowering the quartz crucible 20, a fluctuation occurs in the diameter if the diameter of the ingot is not considered The ingot quality is deteriorated.

From the viewpoint of controlling the pulling speed of the ingot, a difference in melt gap occurs even when the pulling rate is changed. Therefore, if the pulling rate is determined considering only the measured diameter of the ingot, the melt gap can not be precisely controlled Occurs.

That is, since the crucible lifting speed controlled by the measured diameter and the controlled melt gap are closely related, there is a need to consider each other when controlling the both.

FIG. 2 is a graph showing an actual measured ADC value and a corrected ADC value according to an embodiment of the present invention, and FIG. 3 is a graph illustrating a relationship between a target diameter for correcting an actually measured ADC value Represents a correction value (Dia. Target scheduler).

Referring to FIGS. 2 and 3, it can be seen that the corrected ADC value is obtained by subtracting the target diameter correction value from the ADC value actually measured by the ADC sensor.

This is because the melt gap is changed as the pulling speed is controlled, so that it is predicted that the crucible lifting speed will also be changed by the changed melt gap to control the pulling speed.

More specifically, if the pulling rate is controlled only by the actually measured ADC value, a difference in melt gap occurs and the crucible lifting speed is changed. The change of the crucible lifting speed changes the diameter of the ingot again, and the actually measured ADC value is changed again to change the pulling speed, so that a fluctuation occurs in the diameter of the ingot.

In order to prevent this, the target diameter correction value is predicted in advance through a batch or the like to change the crucible lifting speed when the pulling rate is changed, and then the actual measured ADC value in the ingot growing process is set as the target diameter correction value To change the pulling rate, it is possible to prevent the diameter from fluctuating.

That is, the ADC sensor calculates the corrected ADC value by subtracting the target diameter correction value from the measured ADC value, and controls the pull-up speed to the corrected ADC value, thereby making it possible to produce an ingot having a uniform diameter.

However, the target diameter correction value is designed according to the length of the ingot through data such as the diameter of the ingot grown in the previous batches, the melt gap value, and the like. The target diameter correction value thus determined is the value determined by the previous processes, and there is a difference in various aspects from the present process situation.

For example, since the difference between the previous process condition and the current process condition is inevitable in the process conditions such as the temperature condition inside the chamber 10, the atmosphere, the heater power, etc., the target diameter correction value, The situation can not be reflected as it is.

In particular, since the target diameter correction value can not reflect the degree of change of the melt gap in the current process, there may be a limit in which the fluctuation of the diameter can not be completely controlled only by the target diameter correction value.

<Other Embodiments>

Hereinafter, another embodiment of the present invention will be described with reference to FIGS. 4 to 6. FIG.

Another embodiment of the present invention is to overcome the limitations of the embodiment as described above. By controlling the pulling rate in real time by measuring and reflecting the melt gap in the current process, the diameter of the ingot can be uniformly maintained, .

However, descriptions common to the components described in the embodiment of the present invention will be omitted.

FIG. 4 is a schematic block diagram of an ingot growing apparatus according to another embodiment of the present invention, and FIG. 5 is a flow chart for crucible lifting and pulling rate control according to another embodiment of the present invention, 6 shows a real-time diameter correction value according to the crucible lifting speed change according to another embodiment of the present invention.

4, the ingot growing apparatus of the present embodiment includes a pulling system 400 for adjusting a pulling speed of a cable connected to a seed chuck to adjust a pulling speed, a quartz crucible containing a silicon melt, A melt gap sensor 200 (M / G sensor) for measuring the melt gap, a diameter measuring sensor 300 (ADC sensor) for measuring the diameter of the ingot, And a lifting means control unit 350 (ADC) for controlling the lifting speed to a corrected diameter measurement value.

Particularly, in the ingot growing apparatus of this embodiment, the diameter and the melt gap measured from the diameter measuring sensor 300 and the melt gap sensor 200 are received, and the crucible lifting / lowering speed is controlled through the crucible lifting means 100 And a direct controller 500 for outputting the corrected ADC value to the lifting means control unit 350. [

More specifically, the direct controller 500 receives the melt gap measured in real time from the melt gap sensor 200 and compares the melt gap with the target melt gap to control the crucible lift speed when the error gap is exceeded, The target melt gap can be maintained.

The direct controller 500 predicts that the diameter of the ingot will change due to the change in the crucible lifting speed and corrects the actual ADC value transmitted from the diameter measuring sensor 300 to the lifting means control unit 350 .

The lifting means control unit 350 can raise the ingot at the pulling rate reflecting the melt gap value measured in real time by controlling the lifting means 400 with the corrected ADC value.

For example, the lifting means control unit 350 can improve the diameter deviation of the ingot body portion to within 1 mm by controlling the pulling up speed with the corrected ADC value.

In the above description, the direct controller 500 and the pull-up means control unit 350 are described as separate components, but it is also possible that the direct controller 500 and the pull-

Hereinafter, the process of controlling the crucible lifting speed and the pulling-up speed will be described in more detail with reference to FIG.

First, when the ingot growth process is started, the melt gap between the heat shield and the silicon melt is measured, and the diameter of the ingot to be grown is measured as the actual ADC value. (S101)

The measured actual melt gap (actual M / G) is compared with the target melt gap (target M / G) set to the target value according to the ingot length to determine whether a difference occurs (S102)

At this time, if the difference between the actual melt gap and the target melt gap does not exceed the allowable value, the crucible lifting speed is maintained and the ADC correction value for correcting the measured ADC value is maintained. (S103)

However, when the difference between the actual melt gap and the target melt gap exceeds the allowable value, the crucible lift speed is changed to control the actual melt gap to the target melt gap. (S104)

For example, if the actual melt gap is smaller than the target melt gap, the crucible lifting speed is slowed down. If the actual melt gap is larger than the target melt gap, the crucible lifting speed is controlled to be faster.

On the other hand, as described above, when the crucible lifting speed is changed, the diameter of the ingot is changed. In order to prevent this, it is necessary to correct the pulling speed in advance when the crucible lifting speed is changed.

Therefore, the ADC correction value is calculated using the actual melt gap while changing the crucible lifting speed, and then corrected by subtracting it from the measured actual ADC value to calculate the corrected ADC value. (S105)

More specifically, the ADC correction value is calculated by calculating the measured actual melt gap with predetermined control logic.

For example, referring to Fig. 6, when the crucible lifting speed is increased by 0.002 [mm / min], the ADC correction value can be calculated as 10 points.

Alternatively, the ADC correction value may be calculated by substituting the actually measured melt gap into the X value, as shown in Equation (2).

For example, if the measured melt gap is 22 mm, the corrected ADC value can be obtained by calculating 247.8, which is calculated by substituting in Equation 2, as the ADC correction value, and subtracting 247.8 from the actual ADC value.

However, as described above, the method of calculating the ADC correction value by the melt gap is only an example, and the present embodiment is not limited thereto.

Then, the corrected ADC value can be calculated by subtracting the ADC correction value from the actual ADC value, as shown in Equation (3).

Finally, the pulling rate is controlled by the corrected ADC value calculated as above, and the ingot growing process is performed. (S106) In other words, the present embodiment can produce ingots having a uniform diameter through feed forward control reflecting process conditions.

Figure 7 is a graph of real-time ADC correction values calculated from a target diameter correction value (dia. Target scheduler) of an embodiment of the present invention and a measured melt gap of another embodiment of the present invention.

Referring to FIG. 7, it can be seen that there is a difference between the target diameter correction value designed from the previous processes and the ADC correction value calculated in real time.

As a result, it can be seen that the diameter of the ingot is controlled more precisely by controlling the process in real time in accordance with each process situation, as opposed to controlling the current process with a fixed target diameter correction value without reflecting the process condition.

10: chamber
20: Quartz crucible
50: Thermal Shield
60: Sid Chuck
100: crucible lifting means
200: Melt gap sensor
300: Diameter measuring sensor
400: Impression means
500: Direct controller

Claims (11)

1. An ingot diameter control device for controlling an ingot growing apparatus for pulling up an ingot from a silicon melt contained in a quartz crucible by using a seed,
A pull-up means control unit for controlling a pull-up speed of the seed;
A direct controller which receives a measurement value of a melt gap, which is a distance between the silicon melt and the heat shield, from the ingot growing apparatus, and controls the rotation and elevation speed of the quartz crucible in accordance with the melt gap measurement value; And
And an ADC sensor measuring the brightness of the meniscus of the pulled ingot and transmitting the measured diameter value of the ingot to the direct controller as an actual ADC value,
Wherein the direct controller receives an ingot diameter measurement value from the ingot growing apparatus, corrects the diameter measurement value in accordance with the melt gap measurement value, and outputs the corrected diameter measurement value to the lifting means control unit . delete The method according to claim 1,
Wherein the direct controller subtracts the designed target diameter correction value from the diameter measurement value to calculate the corrected diameter measurement value. The method according to claim 1,
Wherein the direct controller calculates the diameter correction value in accordance with the melt gap measurement value and then calculates the corrected diameter measurement value by subtracting the diameter correction value from the diameter measurement value. A quartz crucible for receiving a silicon melt;
A seed chuck for fixing a seed for pulling up the ingot from the silicon melt;
A seed lifting means for lifting the seed chuck by immersing the seed chuck in the silicon melt and lifting the ingot while rotating the seed chuck;
A heat shield forming a melt gap as a heat insulating means on the upper portion of the silicon melt;
A diameter measuring sensor for measuring the diameter of the ingot being pulled up;
A melt gap measurement sensor for measuring the melt gap;
A pull-up means control unit for controlling pull-up speed for pulling up the seed; And
A direct controller that receives the melt gap measurement value from the melt gap measurement sensor and adjusts the rotation and elevation speed of the quartz crucible; Lt; / RTI &gt;
Wherein the direct controller receives a diameter measurement value from the diameter measurement sensor, corrects the diameter measurement value according to the melt gap measurement value, and transmits the corrected diameter measurement value to the lifting means control unit,
Wherein the diameter measuring sensor measures the brightness of the meniscus of the pulled ingot and outputs the measurement value of the diameter of the ingot as an actual ADC value. delete 6. The method of claim 5,
Wherein the direct controller calculates an ADC correction value using the melt gap measurement value and subtracts the ADC correction value from the actual ADC value to output a corrected ADC value. The melt gap at which the ingot growth process is initiated and the distance between the heat shield and the surface of the silicon melt contained in the quartz crucible and the diameter of the ingot to be grown are measured as a current value;
Calculating a difference between the measured current melt gap and a preset target melt gap value to a target value;
Changing the elevation speed of the quartz crucible when the difference is out of a predetermined allowable range and calculating a diameter correction value according to the current melt gap;
Calculating a corrected diameter measurement value by correcting the current diameter measurement value to the diameter correction value;
Controlling the pulling speed of the ingot to the corrected diameter measurement value; &Lt; / RTI &gt; 9. The method of claim 8,
Wherein the step of calculating the diameter correction value calculates the diameter correction value by subtracting the diameter correction value from the current diameter measurement value. 9. The method of claim 8,
Maintaining the previous crucible lifting speed and diameter correction value when the difference is within a predetermined allowable range at the step of calculating the difference; Further comprising the steps of: 9. The method of claim 8,
Wherein the diameter measurement value is measured as an actual ADC value, the diameter correction value is calculated as an ADC correction value, and the corrected diameter measurement value is a correction ADC value.

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