KR20110088164A - Melt gap control system, single crystal growth apparatus and single crystal growth method including the same - Google Patents

Abstract

Embodiments relate to a melt gap control system, a single crystal growth apparatus and a single crystal growth method including the same.
The melt gap control system according to the embodiment is a melt gap control system of a single crystal growth apparatus including a crucible and a heat shield for accommodating a melt, the melt gap being controlled by whether a current flows when the surface of the melt is in contact with the bottom of the heat shield. The gap can be controlled.

Description

Melt Gap Control System, Single Crystal Grower and Method of Manufacturing Single Crystal including the Melt Gap Controlling System}

Embodiments relate to a melt gap control system, a single crystal growth apparatus and a single crystal growth method including the same.

In order to manufacture a silicon wafer, single crystal silicon must first be grown in an ingot form, and the Czochralski (CZ) method may be applied.

The conventional silicon single crystal growth apparatus includes a heat shield to prevent heat radiated from the surface of the silicon melt SM and the heater from being transferred to the silicon single crystal ingot IG.

On the other hand, according to the related art, when the heat shield is installed, it is installed while maintaining a constant gap between the lower end of the heat shield and the free surface of the silicon melt (SM). The melt gap must be kept constant to improve the quality of IG) and increase productivity.

By the way, according to the prior art, the position on the figure is estimated by referring to the design drawing of the single crystal growth apparatus, and then the heat shield is supported and installed at a constant height.

However, when the heat shield is installed by the conventional method, it is difficult to control the melt gap accurately.

Therefore, the prior art measures the melt gap between the heat shield and the melt by contacting the bottom of the heat shield and the surface of the silicon melt for setting the melt gap or measuring the melt gap after the melting process of the silicon melt is completed.

That is, according to the prior art, the operator of the silicon single crystal growth apparatus visually observes the melt surface and the lower end of the heat shield through an external observation mirror, while raising the quartz crucible by a predetermined distance to contact the surface of the silicon melt with the lower end of the heat shield.

Then, by lowering the quartz crucible by a predetermined melt gap distance, the gap between the surface of the heat shield and the silicon melt SM is matched with the preset melt gap.

However, according to the prior art, as the contact between the surface of the silicon melt and the bottom of the heat shield is checked by the naked eye of the operator, an error may occur in the accurate determination of whether the contact is made, thereby precisely controlling the melt gap. There is a difficulty in doing this, and there is a limit in automatically controlling the melt gap since an operator must manually engage in the process in every process.

Embodiments provide a melt gap control system, a single crystal growth apparatus and a single crystal growth method including the same, which improve the accuracy of melt gap control and enable automatic melt gap control.

The melt gap control system according to the embodiment is a melt gap control system of a single crystal growth apparatus including a crucible and a heat shield for accommodating a melt, the melt gap being controlled by whether a current flows when the surface of the melt is in contact with the bottom of the heat shield. The gap can be controlled.

In addition, the single crystal growth apparatus according to the embodiment is a crucible containing a melt; A heat shield installed above the crucible; And a melt gap control system capable of automatically measuring a melt gap, which is a distance between a surface of the melt and a lower end of the heat shield.

In addition, the single crystal growth method according to the embodiment is a single crystal growth apparatus including a crucible and a heat shield, comprising: loading polysilicon into the crucible and heating to form a melt; Contacting the surface of the melt with the bottom of the heat shield; And determining whether a current flows when the surface of the melt and the bottom of the heat shield come into contact with each other.

According to the melt gap control system, the single crystal growth apparatus and the single crystal growth method including the same, the melt gap control is improved by determining whether the melt surface is in contact with the heat shield through the application of current, thereby increasing the accuracy of the melt gap control and automating the melt gap control. May be possible.

In addition, according to the embodiment, by minimizing the melt gap measurement error, it is possible to reduce the defect rate by minimizing the change of the single crystal quality, it is possible to prevent the process accident due to the change of the melt gap in the process.

1 is a schematic view of a single crystal growth apparatus according to the embodiment.
2 to 3 is a melt gap control process chart in the single crystal growth apparatus according to the embodiment.
4 is a diagram illustrating current measurement in a melt gap control system according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

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.

Hereinafter, a melt gap control system according to an embodiment, a single crystal growth apparatus including the same, and a single crystal growth method will be described in detail with reference to the accompanying drawings.

(Example)

1 is a schematic diagram of a single crystal growth apparatus 100 according to an embodiment.

The silicon single crystal growth apparatus 100 according to the embodiment may include a chamber 110, a crucible 120, a heater 130, a pulling unit 140, a heat shield 150, and the like.

For example, the single crystal growth apparatus 100 according to the embodiment is provided in the chamber 110, the inside of the chamber 110, the crucible 120 containing the silicon solution, and the inside of the chamber 110. Is provided in, and may include a heater 130 and a heat shield 150 for heating the crucible 120.

The chamber 110 provides a space in which predetermined processes are performed to grow a single crystal ingot for a silicon wafer used as an electronic component material such as a semiconductor.

Radiant heat insulator 132 may be installed on the inner wall of the chamber 110 to prevent heat of the heater 130 from being discharged to the side wall of the chamber 110.

The embodiment may adjust various factors such as pressure conditions inside the rotation of the quartz crucible 120 to control the oxygen concentration during silicon single crystal growth. For example, in an embodiment, argon gas may be injected into the chamber 110 of the silicon single crystal growth apparatus to discharge the oxygen to control the oxygen concentration.

The crucible 120 is provided inside the chamber 110 to contain the silicon melt SM and may be made of quartz. A crucible support 122 made of graphite may be provided outside the crucible 120 to support the crucible 120.

The crucible support 122 is fixedly installed on the rotary shaft 140, and the rotary shaft 140 is rotated by a driving means (not shown) to rotate and elevate the crucible 120 while having the same interface between the single crystal and the melt. You can keep the height.

The heater 130 may be provided inside the chamber 110 to heat the crucible 120. For example, the heater 130 may be formed in a cylindrical shape surrounding the crucible support 122. The heater 130 melts a high-purity polycrystalline silicon mass loaded in the crucible 120 into a silicon melt SM.

The pulling means 160 may be installed on the upper portion of the chamber 110 so that the cable can be rolled up. Seed crystals S may be installed at the bottom of the cable.

The embodiment may employ a Czochralsk (CZ) method in which seed crystals (S), which are single crystals, are immersed in a silicon melt (SM), and then the crystals are grown while being slowly pulled up.

According to this method, first, a necking process of growing thin and long crystals from seed crystals (S) is followed by a soldering process of growing crystals in a radial direction to a target diameter. After the body growing process to grow into a crystal having a diameter, and after the body grows to a certain length, the single crystal grows through a tailing process that gradually reduces the diameter of the crystal and eventually separates it from the molten silicon. This is the finish.

Meanwhile, before the necking process of the single crystal growth process, polysilicon is loaded into a crucible and heated to form a silicon melt (SM), and a melting process and a stabilization process of the melt are performed.

Thereafter, a process of contacting the bottom of the heat shield 150 and the surface of the silicon melt for setting a melt gap or measuring a melt gap is performed.

In the prior art, as the contact of the surface of the silicon melt and the lower end of the heat shield is checked by the naked eye of the operator, it is difficult to accurately control the melt gap because an error may occur in the accurate determination of the contact. In addition, there is a limit to automatically control the melt gap because the operator must be involved in the process manually in every process.

Embodiments provide a melt gap control system, a single crystal growth apparatus and a single crystal growth method including the same, which improve the accuracy of melt gap control and enable automatic melt gap control.

To this end, the single crystal growth apparatus includes a crucible 120 accommodating the melt SM, a heat shield 150 installed on the crucible 120 and a surface of the melt SM and a lower end of the heat shield 150. It may include a melt gap control system that can automatically measure the melt gap, which is the distance of.

In an embodiment, the melt gap control system contacts the surface of the melt SM with the bottom of the heat shield 150 by whether a current flows when the surface of the melt SM contacts the bottom of the heat shield 150. It is possible to precisely control the melt gap by judging.

Melt gap control system of the embodiment is a power supply (not shown) for applying a current to the crucible 120 or the heat shield 150, the contact of the surface of the melt (SM) and the bottom of the heat shield 150 It may include a current measuring sensor (not shown) for measuring the flow of current and a control unit (not shown) for controlling the melt gap control system.

In the single crystal growth apparatus according to the embodiment, a melt gap measuring rod 152 may be provided at a lower end of the heat shield 150. The melt gap measuring rod 152 may be a silicon single crystal ingot IG to prevent contamination by the melt gap measuring rod 152 and may be a material that does not melt inside the high-temperature chamber 110, and is electrically conductive. Can be.

The embodiment may control the melt gap by flowing a current when the surface of the melt SM contacts the melt gap measuring rod 152 in order to increase the precision of the melt gap control.

Hereinafter, the melt gap control process in the single crystal growth apparatus according to the embodiment will be described with reference to FIGS. 2 to 3.

First, polysilicon is loaded into the crucible 120 and heated to form a melt SM. Thereafter, the stabilization process for the melt (SM) is performed.

Thereafter, as shown in FIG. 2, the step of contacting the surface of the melt SM and the lower end of the heat shield 150 is performed. For example, the crucible 120 may be raised to allow the surface of the melt SM to contact the lower end of the heat shield 150, but is not limited thereto.

At this time, in the embodiment, the melt gap measuring rod 152 is installed at the bottom of the heat shield in order to increase the precision of the melt gap control, and a current flows when the surface of the melt SM contacts the melt gap measuring rod 152. The melt gap can be controlled by whether or not.

Thereafter, as shown in FIG. 3, it may be determined whether current flows when the surface of the melt SM is in contact with the bottom of the heat shield 150.

For example, determining whether current flows when the surface of the melt SM and the bottom of the heat shield 150 are in contact with each other, may apply a current to the crucible 120 or the heat shield 150. .

To this end, an embodiment of the present invention provides a power supply (not shown) for applying a current to the crucible 120 or the heat shield 150, and a current at the contact of the surface of the melt SM and the bottom of the heat shield 150. It may include a current measuring sensor (not shown) for measuring the flow and a controller (not shown) for controlling the melt gap control system.

When a current is applied to the crucible 120 or the heat shield 150, a closed circuit is formed when the bottom of the heat shield 150 contacts the surface of the melt SM, so that a condition may be established in which a current can flow.

4 is an exemplary view illustrating a current measurement in a melt gap control system according to an embodiment, wherein the X axis is a flow of time required for controlling the melt gap, and a unit may be seconds, but is not limited thereto. The current value measured by the measuring sensor may be amperes.

As shown in FIG. 4, the current It according to the contact (Δt = t 2 -t 1) during the contact time between the surface of the melt SM and the bottom of the heat shield 150 may be measured. Then, the crucible 120 is measured as the current value is 0 ampere.

According to the embodiment, when the current It value according to the contact is measured in the current measuring sensor, the melting gap D1 may be set in the process conditions by stopping the crucible rising and lowering the crucible 120.

For example, in FIG. 3, when the length of the melt gap measuring rod 152 from the bottom of the heat shield 150 is referred to as L, the L gap at the melt gap D1 may be set to set the melt gap D1 of desired process conditions. The melting gap can be precisely controlled by lowering the crucible by D2 minus length.

According to the melt gap control system, the single crystal growth apparatus and the single crystal growth method including the same, the melt gap control is improved by determining whether the melt surface is in contact with the heat shield through the application of current, thereby increasing the accuracy of the melt gap control and automating the melt gap control. May be possible.

In addition, according to the embodiment, by minimizing the melt gap measurement error, it is possible to reduce the defect rate by minimizing the change of the single crystal quality, it is possible to prevent the process accident due to the change of the melt gap in the process.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

In addition, the above description has been made with reference to the embodiments, which are merely examples and are not intended to limit the embodiments, and those skilled in the art to which the embodiments belong may not be exemplified above without departing from the essential characteristics of the embodiments. It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to these modifications and applications will have to be construed as being included in the scope of the embodiments defined in the appended claims.

Claims (11)

In the melt gap control system of a single crystal growth apparatus comprising a crucible and a heat shield for receiving a melt,
Melt gap control system for controlling the melt gap by the flow of current in the contact of the surface of the melt and the bottom of the heat shield. The method according to claim 1,
A power supply for applying a current to the crucible;
A current measuring sensor measuring a flow of current when the surface of the melt is in contact with the bottom of the heat shield; And
Melt gap control system comprising a; control unit for controlling the power supply, the current measuring sensor. The method according to claim 1,
A power supply unit applying a current to the heat shield;
A current measuring sensor measuring a flow of current when the surface of the melt is in contact with the bottom of the heat shield; And
Melt gap control system comprising a; control unit for controlling the power supply, the current measuring sensor. A crucible to accommodate the melt;
A heat shield installed above the crucible; And
And a melt gap control system capable of automatically measuring a melt gap, the distance between the surface of the melt and the bottom of the heat shield. The method of claim 4, wherein
The melt gap control system,
Single crystal growth apparatus for controlling the melt gap by the flow of current when the surface of the melt and the bottom of the heat shield in contact. The method of claim 5,
The melt gap control system,
A power supply for applying a current to the crucible or the heat shield;
A current measuring sensor measuring a flow of current when the surface of the melt is in contact with the bottom of the heat shield; And
And a control unit for controlling the melt gap control system. The method of claim 4, wherein
Single crystal growth apparatus having a melt gap measuring rod at the lower end of the heat shield. The method of claim 7, wherein
The melt gap control system,
Single crystal growth apparatus for controlling the melt gap by the flow of current when the melt gap measuring rod and the surface of the melt. In the single crystal growth apparatus comprising a crucible and a heat shield,
Loading polysilicon into the crucible and heating to form a melt;
Contacting the surface of the melt with the bottom of the heat shield; And
And determining whether a current flows when the surface of the melt and the bottom of the heat shield come into contact with each other. 10. The method of claim 9,
The step of contacting the surface of the melt and the bottom of the heat shield,
Single crystal growth method of moving the crucible to contact the surface of the melt and the bottom of the heat shield. 10. The method of claim 9,
Determining whether the current flows when the surface of the melt and the bottom of the heat shield contacts,
Applying a current to the crucible or the heat shield;
And measuring the flow of current upon contact of the surface of the melt with the bottom of the heat shield.

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