KR20070009838A - Apparatus for growing the silicon single crystal - Google Patents

Abstract

An apparatus for growing silicon single crystal is provided to finely control a melt convection rotary region by supplying electric currents to an electrode, while the electrode and an electrode protective pipe are moved in a longitudinal direction of an ingot. A case(16) is installed on an upper portion of a furnace, and an electrode(21) is immersed in a silicon solution to supply an electric current to the silicon solution. An electrode protective pipe(22) encloses an outer periphery of the electrode to protect the electrode and maintain an electrically conducted state between the electrode and the silicon solution. An electrode moving member(10) is installed to one side of the case to move the electrode and the electrode protective pipe in the furnace. The electrode moving member has a horizontally moving member and a vertically moving member.

Description

Silicon single crystal growth apparatus {APPARATUS FOR GROWING THE SILICON SINGLE CRYSTAL}

Figure 1a schematically shows the configuration of a silicon single crystal growth apparatus according to the present invention.

FIG. 1B is a schematic plan view as seen from 'A' of FIG. 1A; FIG.

Figure 2a is a schematic view showing the configuration of the left and right moving device of the electrode moving device of FIG.

FIG. 2B is a schematic side view of FIG. 2A;

FIG. 2C is a schematic plan view of FIG. 2A;

Figure 3a is a schematic view showing the configuration of a moving device of the electrode moving device of Figure 1;

3B is a schematic side view of FIG. 3A.

3C is a schematic plan view of FIG. 3A.

4A and 4B illustrate a state in which the Lorentz force application region is varied according to the position of the electrode.

5A and 5B show the location of the crucible and the Lorentz force application region according to the beginning and the end of the body.

6a and 6b are schematic views showing the position and the moving direction of the electrode according to the installation of two or more electrodes.

<Description of the symbols for the main parts of the drawings>

1. Chamber

2. axis of rotation

3. Crucible

4. Heater

5. Support

6. Ingot

7. Thermostat

8. Silicone Melt (SM)

10. Electrode moving device

11. Base

12. Left and Right Travel Motor

13. Left & Right Pinion Gears

14. Left & Right Movement Racks

15. Roller guide

16. Case

21. Electrode

22. Electrode protection tube

31. First Motor

32. First roller guide

33. First Rack Gear

34. First Pinion Gear

35. Second Motor

36. 2nd Pinion Gear

37. Second Rack Gear

38. Second roller guide

41. Wire connection

The present invention relates to a silicon single crystal growth apparatus, and more particularly, to a silicon single crystal growth apparatus for increasing the uniformity of the quality in the radial direction and the quality in the longitudinal direction by employing an electrode moving device.

A semiconductor single crystal wafer used as a substrate for an ultra-high density (VLSI) electronic device is a Czochralski that pulls a semiconductor single crystal from the silicon melt SM rotating in a silicon single crystal growth device while rotating the semiconductor single crystal in the opposite direction to the melt. , CZ) is fostered by law.

The silicon melt held in the crucible receives heat from a heater installed around the crucible, and the crucible is rotated to make the temperature distribution in the melt axially symmetric with respect to the pulling axis of the crystal.

Conventional techniques have generally been a method of mechanically rotating an axis supporting a crucible in a heater. In this method, when the grown semiconductor crystal has a large diameter such as 30 cm or more, the amount of supported silicon melt becomes 300 kg or more, and the whole apparatus is enlarged. When the crucible is rotated at a constant rotational speed with the enlargement of the apparatus, The axis of rotation is eccentric.

On the other hand, as a method of spontaneously rotating the silicon melt, there is a method of energizing a phase alternating current to the heater. However, in this method, the temperature fluctuation of the heater occurs for alternating current supply, and the temperature fluctuation also occurs in the silicon melt. When the semiconductor single crystal thus grown is large-sized, deformation of the heater due to alternating current is generated, and the reinforcement of the heater is required, which is not suitable for large-size.

Another method for spontaneously rotating the silicon melt is a method of forming a rotating magnetic field by an electromagnet coil. In order to uniformly rotate the magnetic field by this method, it is necessary to control the energization phase of the coil, to precisely control the coil positional relationship, and to control at an arbitrary rotation speed.

In addition, a method of preventing the incorporation of impurities for semiconductors and other impurities other than oxygen into the grown semiconductor crystals by applying a current to the silicon melt with electrodes made of the same composition as the semiconductor single crystals grown during single crystal growth. No. 1999-263691.

However, this method can prevent the incorporation of impurities because the single crystal of the semiconductor and the material of the electrode are the same, but there is a problem in that the electrode is melted by the heat of the silicon melt and is disconnected.

In order to solve this problem, a semiconductor crystal growing apparatus is disclosed in Japanese Patent Laid-Open No. 2000-53488 in which an electrode for applying a current in a silicon melt is passed through a tube surrounding the electrode. This technique arranges a protective tube made of a crucible-like material around an electrode made of a material of the same composition for applying a current to the silicon melt so that the contact between the electrode and the silicon melt does not break out, and the current is always applied during crystal growth. It is a method of growing crystals, preventing deformation of the semiconductor surface due to insertion of electrodes, and increasing rotational symmetry of the melt.

However, in the case of the above technique, the electrode is made of a solid phase of the same material as the silicon melt to prevent contamination of the melt. However, when remelting the grown ingot, the temperature is significantly higher than that of the melt used for ingot growth. Will be maintained. As a result, the electrode for supplying the current to the melt becomes at a temperature equal to or higher than the melting point and is melted to damage the electrode. In addition, even when a protective tube surrounding the electrode is provided to protect the electrode, the protective tube is made of quartz in the growth apparatus of the silicon single crystal ingot, and thus there is a risk of damage such as partial melting due to remelting heat.

In order to solve such a problem, Korean Patent Application No. 2003-0076418, filed by the applicant of the present invention, regenerates a single crystal grown in the case of dislocation occurring during single crystal growth by raising the temperature of the silicon melt to a very high temperature. When growing, a silicon single crystal growth apparatus is disclosed, which maintains the electrode and the electrode protecting tube stably by using an electrode protecting tube moving device and an electrode moving device and continuously applies current again when growing the single crystal.

On the other hand, as the body process proceeds, as the length of the ingot increases, the free surface of the silicon melt gradually decreases as the residual amount of the silicon melt decreases. To prevent this, the crucible is gradually raised upwards during the body process. As described above, when the amount of application of the Lorentz force is the same as the residual amount of the silicon melt is different, the Lorentz force is relatively changed in the initial body process and the late process.

Therefore, the above-described technology is merely a method of protecting the electrode and the electrode protective tube from re-melting heat, and the above-mentioned problem occurs. Also, the Lorentz force is relatively different in the ingot crystal length and radial directions. It causes unevenness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a silicon single crystal growth apparatus which increases the symmetry of the Lorentz force applied region to increase the uniformity of the quality in the radial direction and the quality in the longitudinal direction. The purpose is to provide.

Silicon single crystal growth apparatus of the present invention for achieving the above object, the silicon single crystal growth apparatus for rotating the silicon melt in the crucible to be grown into a single crystal ingot by electromagnetic force, the case provided on the top of the crucible; An electrode installed in the silicon melt to supply current to the silicon melt; An electrode protective tube surrounding the outer circumferential surface of the electrode to protect the electrode and maintaining an energized state between the electrode and the silicon melt; And an electrode moving device installed at one side of the case to move the electrode and the electrode protective tube vertically and horizontally in the crucible.

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

Figure 1a is a front view schematically showing the configuration of a silicon single crystal growth apparatus according to the present invention, Figure 1b is a schematic plan view seen from 'A' in Figure 1a, Figures 2a to 2c is Figure 1a The configuration of the electrode transfer device is shown in more detail.

Referring to the drawings, the silicon single crystal growth apparatus according to the present invention rotates the silicon melt (SM) 8 in the crucible 3 grown to the single crystal ingot 6 by electromagnetic force, The silicon single crystal ingot 6 grows inside. That is, a crucible 3 made of quartz and containing a silicon melt 8 is installed in the chamber 1, and a support 5 for supporting the crucible 3 made of graphite is provided outside the crucible 3. It is installed to enclose the crucible 3.

And the support (5) is fixedly installed on the rotating shaft (2), the rotating shaft (2) is rotated by a driving means (not shown) to raise while rotating the crucible (5) the solid-liquid interface is the same height Keep it.

The support 5 is also surrounded by a cylindrical heater 4 at predetermined intervals, which is surrounded by a thermos 7. The heater 4 melts the high-purity polycrystalline silicon mass loaded in the crucible 3 into a silicon melt 8, and the heat insulating tube 7 has heat generated from the heater 4 in the chamber 1. Improves thermal efficiency by preventing diffusion to the wall.

Also, as a feature of the present invention, as illustrated in FIGS. 1A and 1B, the case 16 installed on the top of the crucible 3 and the silicon melt 8 for supplying current to the silicon melt 8 are provided. 8 and an electrode protective tube for protecting the electrode 21 by surrounding the outer circumferential surface of the electrode 21 and holding the energized state between the electrode 21 and the silicon melt 8. And an electrode moving device 10 provided on one side of the case 16 to move the electrode 21 and the electrode protective tube 22 up, down, left and right in the crucible 3.

In addition, the electrode moving device 10, as shown in Figure 2a to 2c, is installed on the other side of the case 16, the left and right moving device for moving the electrode 21 and the electrode protective tube 22 to the left and right. And, and as shown in Figure 3a to 3c, is installed on one side of the case 16 is configured to include a moving device for moving the electrode 21 and the electrode protective tube 22 up and down.

More specifically, the left and right movement apparatus, as shown in Figs. 2a to 2c, the base 11 is installed on one side of the case 16 so as to be movable left and right, the base 11 and the case 16 It is installed on each side of the) is configured to include a base moving means for moving the base 11 to the left and right to move the electrode 21 and the electrode protective tube 22 to the left and right.

The base moving means includes a left and right moving motor 12 provided on one side of the base 11, a left and right moving pinion gear 13 provided on a motor shaft of the left and right moving motor 12, and the left and right moving pinion gear. It is configured to include a left and right moving rack gear 14 provided on one side of the case 16 to engage with (13).

In addition, the roller guide 15 is installed at one side of the bottom of the base 11 to facilitate the movement of the base 11.

Specifically, as shown in FIGS. 3A to 3C, the movable device is rotatably installed on one side of the base 11 and the upper side of the base 11 so as to be rotatable. The first roller guide 32 for guiding the 21, the second roller guide 38 for rotatable at the lower side of the base 11 to guide the electrode protective tube 22, and the first, It comprises a rotating means for rotating the two roller guides (32, 38).

The rotation means includes a first motor 31 provided on an upper side of the base 11, a first pinion gear 34 provided on a motor shaft of the first motor 31, and the first pinion gear. The first rack gear 33 and the second motor provided on the lower side of the base 11 and the first rack guide 32 is engaged with the (34) and is moved up and down to rotate the first roller guide (32). (35), the second pinion gear (36) provided on the motor shaft of the second motor (35), and the second pinion gear (36) are engaged with and lifted to rotate the first roller guide (32) to rotate the electrode. It comprises a second rack gear 37 to allow the protective tube 22 to be elevated.

In addition, as shown in FIGS. 6A and 6B to be described later, at least two electrode moving devices 10 configured as described above are provided, and thus two or more electrodes 21 are installed at the same angle. However, the present invention is not necessarily limited thereto.

Meanwhile, reference numeral 41, which is not described in FIGS. 3A and 3B, shows a wire connection part.

Referring to the operation of the silicon single crystal growth apparatus according to the present invention having the configuration as described above is as follows.

Referring back to the drawings, the silicon single crystal growth apparatus according to the present invention is a device for applying a magnetic field to the silicon melt 8 as a method of spontaneously rotating the silicon melt 8 by the Czochralski (CZ) method, and a magnetic field. A device for applying a current orthogonal to the silicon melt 8 and a method for continuously applying a current using the electrode 21 for applying a current to the silicon melt 8 are applied.

In the silicon single crystal growth apparatus according to the present invention, the current-applying electrode 21 moves in the radial direction during the growing process, and supplies a current to fine the size of the melt convection rotation region by the Lorentz force. This is to increase the uniformity of the quality of the wafer in the radial direction and the quality of the ingot 6 in the longitudinal direction.

This will be described in more detail.

First, the silicon single crystal growth apparatus according to the present invention includes an electrode movement apparatus including a left and right movement apparatus for moving the electrodes 21 and the electrode protective tube 22 up and down and up and down and the shank movement apparatus on the chamber 1 ( 10), in particular, the left and right movement apparatus moves the base 11 of the case 16 to the left and right as shown in FIGS. 2A to 2C so that the electrode 21 and the electrode protective tube 22 are left and right. It consists of a left and right movement motor 12, a left and right movement pinion gear 13, and the left and right movement rack gear 14 to drive the left and right movement motor 12 to move to the left and right movement pinion gear 13 and left and right. By rotating the movable rack gear 14, the electrode 21 and the electrode protective tube 22 are moved left and right. At this time, the roller guide 15 is installed at the bottom of the base 11, the movement of the base 11 is smooth.

As shown in FIGS. 3A to 3C, the movable device includes first and second roller guides 32 and 38 for guiding the electrode 21 and the electrode protective tube 22 on the upper and lower portions of the base 11. ), And the first and second motors 31 and 35 are driven to rotate the first and second pinion gears 34 and 35 and the first and second rack gears 33 and 37. 21 and the electrode protective tube 22 are simultaneously raised and lowered.

By moving the electrodes 21 and the electrode protective tubes 22 in the right and left directions as described above, the Lorentz force applying regions A and B can be changed as necessary as shown in Figs. 4A and 4B.

That is, when the position of the electrode 21 is closest to the ingot 6 as a as shown in FIG. 4A, the Lorentz force applying region (hatched 'A') is the electrode 21 of FIG. 4B as shown in the lower figure. ) It is much smaller than the Lorentz force application area (hatched 'B') at position b. When the Lorentz force application region B is small, the rotation region of the silicon melt 8 is also reduced. A marangoni force is applied to the free surface of the silicon melt 8, and the magnitude of the marangoni force can be controlled by adjusting the sizes of the Lorentz force applying regions A and B. This can further increase the uniformity of the quality of the wafer.

During the body growth of the ingot 6, the electrode 21 may move from FIG. 4A to FIG. 4B at a constant speed, or vice versa.

In order to grow the silicon melt 8, the polycrystalline semiconductor raw material is first put into the crucible 3, the chamber 1 containing the crucible 3 is kept close to a vacuum, and then the heater 4 surrounding the crucible 3 is formed. The power is gradually raised to completely melt the solid polycrystalline semiconductor. After the temperature of the fully melted silicon melt 8 is set to an appropriate temperature for drawing, the prepared single crystal seed crystals are immersed in the silicon melt 8.

At this time, the electrode 21 for applying the current is immersed in the silicon melt 8 together using a moving device for moving the electrode 21 up and down as shown in FIGS. 3A to 3C. After a predetermined time has elapsed, the seed crystal is pulled upward at a constant speed to perform a necking process for dislocation removal, and a shouldering process for growing the necessary diameter. The body process starts immediately after the shouldering process.

Note that the position of the crucible 3 is fixed until the shouldering process. However, as the length of the ingot 6 increases as the body progresses, the free surface of the silicon melt 8 gradually decreases as the residual amount of the silicon melt 8 decreases. The position of (3) is gradually raised upward.

In the first half of the body, the amount of the silicon melt 8 is high and the position of the crucible 3 is low, as in FIG. 5A. In the second half of the body, the amount of the silicon melt 8 is small and the position of the crucible 3 is low, as shown in FIG. 5B. Will be higher.

As the residual amount of the silicon melt 8 is changed as described above, when the application area of the Lorentz force is the same, the force applied to the silicon melt 8 becomes relatively different at the beginning and the second half of the body.

However, by applying the silicon single crystal growth apparatus according to the present invention, by placing the electrode 21 in the position of b as shown in Fig. 5a at the beginning of the body, the position of the electrode 21 in the latter part of the body as shown in Fig. 5b by Lorentz It is possible to change the force application area (hatched part B) and to keep the relative force of Lorentz force the same at the beginning and the end of the body.

Thereby, the uniformity of the quality in the crystal longitudinal direction and the quality in the radial direction of the ingot 6 can be increased. If necessary, the operation may be performed in the reverse manner to those in FIGS. 5A and 5B.

6A and 6B illustrate a case where two or more electrodes 21 are applied by applying two or more electrode moving devices 10. Thus, in order to increase the symmetry of the Lorentz force application region C, there may be a case where two or more electrodes 21 are used. In this case, the electrode during the body drawing process using the electrode moving device 10 may be applied. The position of 21 may be varied, and the size of the Lorentz force application region C may be varied.

In addition, although not shown in the figure, it is also possible to move the position of the electrode 21 up and down, as well as to move the position of the electrode 21 to the left and right during body drawing.

After the body is finished, the ingot 6 is cooled in the chamber 1 after the tailing process is performed to reduce the diameter of the ingot 6 again. Then it is taken out, cut and made into wafers.

As described above, the silicon single crystal growth apparatus according to the present invention has the following effects.

During the drawing process, the current applying electrode and the electrode protective tube are moved in the radial direction of the silicon melt and the longitudinal direction of the ingot, and the current is supplied to finely control the size of the melt convection rotation region by the Lorentz force. And the uniformity of the quality in the ingot length direction can be increased.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (9)

In a silicon single crystal growth apparatus for rotating a silicon melt in a crucible grown into a single crystal ingot by electromagnetic force, A case installed on the top of the crucible; An electrode installed in the silicon melt to supply current to the silicon melt; An electrode protective tube surrounding the outer circumferential surface of the electrode to protect the electrode and maintaining an energized state between the electrode and the silicon melt; And an electrode moving device installed at one side of the case to move the electrode and the electrode protective tube vertically and horizontally in the crucible. The method of claim 1, The electrode moving device, A left and right moving apparatus installed on the other side of the case to move the electrode and the electrode protective tube from side to side; And a copper moving device installed on one side of the case to move the electrode and the electrode protection tube up and down. The method of claim 2, The left and right moving device, A base installed to be movable left and right on one side of the case; And a base moving unit installed at each side of the base and the case to move the base from side to side to move the electrode and the electrode protective tube from side to side. The method of claim 3, The base moving means, A left and right moving motor installed at one side of the base; A left and right moving pinion gear mounted to a motor shaft of the left and right moving motors; And a left and right shifting rack gear installed on one side of the case so as to be engaged with the left and right shifting pinion gears. The method of claim 4, wherein Silicon single crystal growth apparatus, characterized in that the roller guide is installed on one side of the bottom of the base to facilitate the movement of the base. The method of claim 2, The Shanghai copper device, A base installed on one side of the case; A first roller guide rotatably installed at an upper side of the base to guide the electrode; A second roller guide rotatably installed at one lower side of the base to guide the electrode protective tube; And a pivoting means for rotating the first and second roller guides. The method of claim 6, The rotation means, A first motor installed at an upper side of the base; A first pinion gear installed at the motor shaft of the first motor; A first rack gear meshed with the first pinion gear and lifted to rotate the first roller guide to lift and lower the electrode; A second motor installed at one lower side of the base; A second pinion gear installed on the motor shaft of the second motor; And a second rack gear meshed with the second pinion gear and lifted to rotate the first roller guide to lift and lower the electrode protective tube. The method of claim 1, At least two electrode moving devices are installed. The method of claim 8, And at least two electrodes of the electrode transfer device are installed at the same angle.

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