KR101069911B1 - a silicon single crystal ingot grower used czochralski method and controlling method of the same - Google Patents

Abstract

The silicon single crystal ingot growth apparatus of the present invention forms and maintains a constant thermal environment around the silicon single crystal ingot interface to improve the quality of the ingot and the pulling speed, and to facilitate the pulling speed control. a chamber forming a hot zone, a seed crystal chuck positioned vertically inside the chamber, an impression drive connected to the seed crystal chuck outside the chamber, and containing molten silicon in a hot zone inside the chamber. Crucible, rotary driving device for supporting the crucible from the outside of the chamber, a plurality of heaters each independently disposed and controlled in the upward direction of the crucible while enclosing the periphery of the crucible, and a heat shield between the heater and the chamber .

Heater, Crucible, Seed Crystal, Ingot, Interface, Thermal Environment

Description

{A silicon single crystal ingot grower used czochralski method and controlling method of the same}

1 is a cross-sectional view schematically showing a silicon single crystal ingot growth apparatus according to an embodiment of the present invention.

2 is a block diagram of a silicon single crystal ingot growth apparatus according to an embodiment of the present invention.

3 to 5 are control state diagrams over time for growing a silicon single crystal ingot as a method for controlling a silicon single crystal ingot growth apparatus according to an embodiment of the present invention.

The present invention relates to a method for controlling a silicon single crystal ingot growth apparatus, and more particularly, to uniformly form and maintain a thermal environment around a silicon single crystal ingot interface, to maintain the quality and pulling speed of the ingot even if the length of the ingot increases. The present invention relates to a silicon single crystal ingot growth apparatus for facilitating pulling rate control and a control method thereof.

In general, in a silicon single crystal ingot growth apparatus, a silicon single crystal ingot (ingot) is a molten silicon formed by melting polysilicon and a dopant in a crucible, using an impression driving apparatus. This is produced by dipping the seed crystals and slowly pulling up the seed crystals while rotating the seed crystals and the crucible in opposite directions.

The silicon single crystal ingot growth apparatus is a seed crystal chuck which is connected to the impression driving device, the chamber, and the impression driving device, and a crucible in which molten silicon is contained in a hot zone inside the chamber. And a heat shield for shielding the heat generated from the heater from being radiated to the outside and the temperature of the molten silicon from being lowered.

In the Czochralski method, the level of molten silicon decreases as the ingot grows, but the crucible height is raised by the level reduction of the molten silicon to keep the level of molten silicon constant for the heater.

However, since the heater is integrally formed around the crucible and maintained in a fixed state, as the length of the ingot becomes longer, a relative position difference between the crucible and the crucible operating in the heater increases. This position difference causes a change in the thermal environment around the ingot interface as the ingot grows.

Changes in the thermal environment around this ingot interface make it difficult to achieve uniform quality of the ingot. In addition, at the end of ingot growth, most of the heat radiated from the heater does not act on the heating of the crucible, and only a part of the crucible heats the bottom of the crucible, making it difficult to control the pulling speed of the ingot, and the change of the thermal environment around the ingot interface is intensified. Will slow down the pulling speed.

Most of the heat generated in the heater does not act on the heating of the crucible, and thus, the ingot growth time is delayed because the pulling speed of the ingot is lowered. This wastes unnecessary power.

In addition, as the diameter and size of the silicon wafer are increased, the necessity of controlling the rapid thermal environment change around the ingot interface due to the pulling of the large diameter ingot is required.

The present invention is to solve the above problems, an object of the present invention is to form and maintain a constant thermal environment around the silicon single crystal ingot interface to improve the quality and pulling speed of the ingot, easy to control the pulling speed The present invention provides a method of controlling a silicon single crystal ingot growth apparatus.

The silicon single crystal ingot growth apparatus according to the present invention includes a chamber for forming a hot zone therein, a seed crystal chuck positioned vertically inside the chamber, and connected to the seed crystal chuck outside the chamber. Impression driving device, crucible containing molten silicon in the hot zone inside the chamber, rotary driving device supporting the crucible from the outside of the chamber, and a plurality of independently controlled and arranged in the rising direction of the crucible while surrounding the crucible And a heat shield interposed between the heater and the chamber.

The heater is a first heater disposed in the lower side in the rising range of the crucible, a second heater disposed in a straight line on the upper side of the first heater, and a third heater disposed in a straight line on the upper side of the second heater. It may include a heater.

The heater may be formed of a carbon heater in which heat generation is turned on / off through resistance heat generation, or may be formed of a carbon heater in which the output is variable through resistance resistance.

Preferably, the heater, that is, the first heater, the second heater, and the third heater are connected to a control unit for controlling the pulling-up driving device and the rotary driving device, and are controlled on / off corresponding to the rising position of the crucible.

In addition, the method for controlling a silicon single crystal ingot growth apparatus according to the present invention is a method for controlling a silicon single crystal ingot growth apparatus in which polycrystalline silicon is melted by a Czochralski method and grown into a silicon single crystal ingot. Is raised in a plurality of heaters arranged in its upward direction, and during the step, the position of the ingot interface formed between the lower end of the ingot and the molten silicon changes in the crucible corresponding to this ingot interface position. Selectively turning on / off the heaters.

The control step may initially control the heaters in the rising range of the crucible to be initially turned on, and sequentially control off the heaters corresponding to the position away from the bottom of the crucible as the crucible is raised.

The control step initially controls the first heater, the second heater, and the third heater, which are sequentially disposed in this rising direction within the rising range of the crucible, to be turned on, and the position of the crucible as it is lifted off from the lower end of the crucible. The first heater and the second heater corresponding to the off can be sequentially controlled.

The control step may vary the output according to the diameter of the ingot.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing a silicon single crystal ingot growth apparatus according to an embodiment of the present invention.

Referring to this figure, the silicon single crystal ingot growth apparatus includes a chamber 2 forming a main body of the apparatus and forming a hot zone (H / Z) therein, and an up and down direction inside the chamber (2). A seed crystal chuck 4 for fixing the seed crystal S, positioned in the vertical direction in the drawing), and an impression driving device 6 connected to the seed crystal chuck 4 for raising and rotating the seed crystal S therein; ), A crucible (8) provided in the hot zone (H / Z) containing polycrystalline molten silicon (M), connected to and supporting the crucible (8) while being pulled and rotated by the impression driving device (6). The rotary drive device 10 which raises the crucible 8 while rotating in the opposite direction to the rotation direction of the seed crystal chuck 4, which surrounds the periphery of the crucible 8. A plurality of heaters 12 sequentially controlled from bottom to top according to independent control, and And a heat shield 14 is located between (12) and chamber (2).

In this case, the seed crystal chuck 4 is connected to the impression driving device 6 provided outside the chamber 2 through the cable 16. The seed crystal chuck 4 may be formed in a variety of structures and types, and a well-known configuration may be applied, so a detailed description thereof will be omitted here.

When growing and producing a silicon single crystal ingot (I) from polycrystalline molten silicon (M) using the apparatus of this embodiment, the seed crystals (S) described above are required, and the seed crystal chuck (4) It is sufficient if it is configured to be fixed and to transmit the lifting and rotational operating force of the impression driving device (6).

That is, in the Czochralski method, the seed crystal chuck 4 is connected to the pulling-up driving device 6 to dip the seed crystal S into the molten silicon M and pull the seed crystal M again. , To bear the load of the ingot (I) formed by the growth of the silicon single crystal at the end of the seed crystal (S), and rotates the seed crystal (S) while rotating operation in the direction with this pulling operation.

When the seed crystal chuck 4 transmits the pulling actuation force and the rotational force through the cable 16 to the seed crystal S, the rotation center of the cable 16 coincides with the rotation center of the seed crystal S by vibration or the like. In order to maintain and maintain the state, it is preferable to form a weight having a weight capable of sufficiently absorbing vibrations that may occur during lifting and rotation to serve as a weight.

The crucible 8 is a container containing polycrystalline molten silicon (M), which is formed of a quartz crucible which does not react with or reacts with silicon (S ⁺ ) and a graphite crucible that surrounds the quartz crucible from the outside. It can be made of a crucible. The molten silicon M in this crucible 8 forms an ingot interface L in contact with the end of the ingot I grown as a single crystal.

The rotary drive device 10 raises the crucible 8 while rotating the ingot I in the above-mentioned direction when the ingot I grows, so that the interface of the molten silicon M decreases due to the growth of the single crystal ingot I. It is possible to keep the L in a position within a predetermined range with respect to the heater 12. To this end, the rotary drive device 10 is provided on the outside of the chamber 2, the rotary shaft 18 is installed over the inside and outside of the chamber 2 and the support plate 20 provided at the tip of the rotary shaft 18 It is connected to the crucible (8), it is configured to be raised while rotating the crucible (8) through the rotary shaft 18 and the support plate (20).

In the Czochralski method in which polycrystalline silicon is melted to grow a single crystal ingot (I) from the molten silicon (M), the heater 12 radiates heat to the crucible 8 to maintain the molten state of the silicon and the hot zone ( H / Z). In addition, the heat shield 14 prevents heat generated from the heater 12 from being radiated to the outside of the chamber 2 to prevent the temperature of the molten silicon M in the crucible 8 from being lowered.

On the other hand, the heater 12 is composed of a plurality along the upward direction (up and down direction in the drawing) of the crucible 8 forming the ingot I interface L, and sequentially from the lower side to the upper side of the hot zone H / Z. 2 and are respectively connected to the control unit 22 so as to be independently controllable. The control unit 22 may be connected to the impression driving device 6 and the rotary driving device 10.

The heater 12 may be formed in two or more, but in the present embodiment, it consists of three of the first, second, and third heaters 12a, 12b, and 12c, and the first, second, and third heaters. The heaters 12a, 12b, 12c are sequentially arranged along the rising direction of the crucible 8.

That is, the first heater 12a is disposed below the crucible 8 in the rising range, and the second heater 12b is disposed above the first heater 12a in a straight line with the third heater 12c. ) Is disposed in a straight line with the second heater 12b. The first, second, and third heaters 12a, 12b, and 12c may be three, two, or one selected by the control unit 22 to be independently turned on or off.

During ingot I growth, the position of the ingot interface L formed between the lower end of the ingot I and the molten silicon M is changed in the crucible 8. Thus, by raising the crucible 8, the ingot interface L is formed and maintained at a position within a predetermined range with respect to the heater 12.

Therefore, since the heater 12 is fixed in the chamber 2 and the crucible 8 is synergistic in the heater 12, the heater 12 and the crucible 8 are both shown in FIGS. 3 to 5. As shown, there is a relative position difference as the ingot I growth time elapses.

That is, FIG. 3 shows a relative position where the crucible 8 is formed corresponding to the first, second, and third heaters 12a, 12b, 12c, and FIG. 4 shows that the crucible 8 is the second, third heater. The relative position formed corresponding to (12b, 12c) is shown, and FIG. 5 shows the relative position where the crucible 8 is formed corresponding to the 3rd heater 12c.

Despite this relative position difference, it is necessary to maintain a thermal environment within a range around the ingot interface L formed in the crucible 8. As the diameter of the ingot I becomes large, the distance to the center of the heater 12 and the ingot I becomes far. Therefore, the area around the interface L of the large diameter ingot I should be maintained in a thermal environment within a more limited range.

The heater 12 which forms and maintains such a thermal environment may be formed in various ways, and may be configured as a carbon heater that controls heat generation on or off through resistance heat generation.

In addition, although the heater 12 may give the same output, it is more preferable that it is formed with the carbon heater which can change an output through variable resistance. This variable heater 12 can be suitably used for the growth of ingot I having various diameters.

Hereinafter, a control method for controlling the silicon ingot growth apparatus configured as described above will be described. By this control method, single crystal silicon ingot I is grown and manufactured. This control method includes raising the crucible 8 forming the interface L of the ingot I in a plurality of heaters 12 arranged in the upward direction thereof, and during this rising step, the ingot I As the position of the ingot interface L formed between the lower end and the molten silicon M changes in the crucible 8, the heaters 12 corresponding to this ingot interface position are selectively turned on or off.

The ascending step raises the crucible 8 by the rotary drive device 10 and rotates it in a direction opposite to the direction of rotation of the crystal seed chuck 4.

The control step intermittently proceeds at an appropriate time during the ascent step. This control step initially controls the heaters 12 that are within the rising range of the crucible 8 to be initially turned on, and as the crucible 8 is raised, the heater 12 corresponding to the position deviated from the lower end of the crucible 8. To control off sequentially.

That is, the on or off control of the heater 12 is implemented by the control unit 22, for example, the control unit 22 is provided with a separate detection sensor (not shown) the crucible (8) detected by this sensor Correlation between the height of the crucible 8 and the operating time of the impression driving device 6 or the rotary driving device 10 built in the control unit 22 or based on the relative position difference signal of the heater 12). The heater 12 corresponding to the portion of the crucible 8 in which the interface L of the ingot I and the molten silicon M remain, is turned on by using the data having the data, and the heater is out of the crucible 8. (12) may be controlled to be off. Therefore, the present invention is not limited to the method in which the control unit 22 determines the relative position difference between the heater 12 and the crucible 8.

In more detail, as shown in FIGS. 3 to 5.

Referring to FIG. 3, the controller 22 operates all of the first, second, and third heaters 12a, 12b, and 12c at an initial stage of ingot I growth. At this time, the crucible 8 is positioned corresponding to the first, second, and third heaters 12a, 12b, 12c, and at this time, the ingot interface L formed in the molten silicon M in the crucible 8 is the third heater. It is formed corresponding to 12c.

As the first, second, and third heaters 12a, 12b, and 12c are all turned on, the heat generated by the first, second, and third heaters 12a, 12b, and 12c is reduced in the crucible 8. It radiates to the whole range, and keeps the thermal environment of the interface L constant, keeping the temperature of molten silicon M constant.

Referring to FIGS. 4 and 5, ingot I growth continues in the state of FIG. 3, and when the state of FIG. 4 and the state of FIG. 5 are sequentially formed, the controller 22 is a lower end of the crucible 8. The first heater 12a and the second heater 12b corresponding to the position away from the control are sequentially turned off. Therefore, around the interface (L) of the ingot (I) formed in the crucible (8) by the second, third heater (12b, 12c) or the third heater (12c) to maintain the on state, the same thermal environment as the initial Will be maintained.

In FIG. 4, since the lower end of the crucible 8 is out of the range of the first heater 12a, the controller 22 controls off the first heater 12a, thereby generating unnecessary heat that does not act to heat the crucible 8. prevent. Despite this, the ingot I interface L in the crucible 8 is formed at a position corresponding to the third heater 12c as in the initial state, and the surrounding crucible 8 forming this interface L is formed. ) Part is heated by the 2nd, 3rd heaters 12b and 12c, and the surroundings of interface L form and maintain the thermal environment state like the initial stage.

In FIG. 5, since the lower end of the crucible 8 is out of the range of the first and second heaters 12a and 12b, the controller 22 controls the first and second heaters 12a and 12b to turn off the crucible 8. Prevents the generation of unnecessary heat that does not act as a heating. Nevertheless, as described above, the ingot I interface L in the crucible 8 is formed at a position corresponding to the third heater 12c as in the initial state, and the surrounding area forming this interface L is formed. The crucible 8 portion is heated by the third heater 12c so that the surroundings of the interface L continue to form and maintain the same thermal environment as the initial stage.

In addition, in the control step as described above, the control unit 22 may appropriately cope with growth production of the large diameter ingot I by varying the output of the heater 12 according to the diameter of the ingot I. That is, in controlling the first, second, and third heaters 12a, 12b, and 12c on or off as described above, the first, second, and third heaters 12a, 12b according to the diameter of the ingot 1. , 12c) can increase or decrease the output.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

As described above, according to the present invention, in growing and manufacturing a single crystal silicon ingot by the Czochralski method, a heater provided around the crucible is provided to be independently controlled in multiple stages, and despite the rise of the crucible due to ingot growth, By selectively controlling the heater out of the crucible by turning the heater on, the thermal environment around the ingot interface can be uniformly formed and maintained, thereby improving the quality of the ingot and increasing the amount of molten silicon at the end of growth. Even if it is reduced, the pulling speed can be maintained as it is, and since the output of the heater is controlled according to the diameter of the ingot, there is an effect of facilitating the pulling speed control.

Claims (9)

delete delete delete delete delete In the control method of the silicon single crystal ingot growth apparatus for melting polycrystalline silicon by Czochralski method and growing into silicon single crystal ingot, Elevating the crucible forming the ingot interface in a plurality of heaters arranged in the upward direction of the crucible; During the step, selectively turning on / off the heaters corresponding to the position of the ingot interface as the position of the ingot interface formed between the lower end of the ingot and the molten silicon is changed in the crucible. Ingot growth device control method. The method according to claim 6, The controlling step initially controls the heaters within the rising range of the crucible to be turned on, And a control method of the silicon single crystal ingot growth apparatus that sequentially turns off the heater corresponding to the position deviated from the lower end of the crucible as the crucible is raised. The method according to claim 6, The control step may initially control the first heater, the second heater, and the third heater, which are sequentially disposed in the rising direction of the crucible within the rising range of the crucible, And controlling the first heater and the second heater to sequentially turn off the first heater and the second heater corresponding to the position deviating from the lower end of the crucible as the crucible is raised. The method according to claim 6, The control step is a control method of a silicon single crystal ingot growth apparatus for varying the output in accordance with the diameter of the ingot.

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