JP2940892B2 - Single crystal pulling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CZ (Czochralski)
The present invention relates to a single crystal pulling apparatus by a method.

[0002]

2. Description of the Related Art As a conventional silicon single crystal pulling apparatus by the CZ method, there is one described in, for example, Japanese Patent Publication No. 57-40119. In this apparatus, a space in contact with a silicon melt, a quartz crucible, and a graphite susceptor was covered by a conical screen during pulling up of a silicon single crystal rod. This screen prevents heat radiation from the silicon melt to the growing silicon single crystal rod, and also prevents reaction with carbon monoxide from carbon parts such as a heater and a graphite susceptor.

[0003]

However, in such a conventional single crystal pulling apparatus by the CZ method, for example, by raising the temperature of the melt to prepare a tail, the single crystal constant diameter portion is formed. Thermal history of the part near the tail of the crystal (time during which each part of the crystal is exposed to an arbitrary temperature during pulling)
However, it differs from the upper and middle fixed diameters. For this reason, the OSF (Oxidation induced Stacking Folding) is often placed on the tail of the pulled silicon single crystal rod and its vicinity.
There is a problem that a stacking fault called “ault” occurs, and there is a problem to prevent this. Further, since oxygen precipitation also becomes abnormal, there was a problem that the oxygen precipitation was made the same as the upper part.

[0004] Therefore, the present invention provides a method of manufacturing a silicon single crystal rod in which 850 to 1
Provided is a single crystal pulling apparatus capable of suppressing the occurrence of OSF in a silicon single crystal rod and improving the quality of the silicon single crystal rod by not receiving a heat history in a temperature range of about 050 ° C. for a long time. Is its purpose.

[0005]

According to a first aspect of the present invention, there is provided a single crystal pulling apparatus, comprising: a quartz crucible for holding a crystal melt;
A heater that heats the crystal melt, a pulling mechanism that pulls a single crystal rod from the crystal melt, and a shield that shields heat that propagates from the crystal melt to the single crystal rod, while the single crystal rod is pulled up In a single crystal pulling apparatus provided with a shielding member having an opening, the area of the opening of the shielding member is made variable.

[0006]

In the single crystal pulling apparatus according to the present invention, the heat history is equalized over the entire crystal by raising the single crystal rod and changing the area of the opening of the shielding member so that the tail portion is A temperature range that promotes the generation of OSF,
For example, it is possible to shorten the time of being located in a temperature range of about 850 to 1050 ° C. As a result, the O
Generation of SF can be prevented, and a uniform single crystal can be manufactured.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a single crystal silicon pulling apparatus according to one embodiment of the present invention. FIG. 2 shows II-II in FIG.
It is a line sectional view.

As shown in these figures, a silicon melt 6 is held in a quartz crucible 5 of the single crystal pulling apparatus 1. A heater 7 for heating the silicon melt 6 is provided so as to surround the outside of the quartz crucible 5. Above the quartz crucible 5, a pulling mechanism (not shown) for pulling the single crystal silicon rod 8 is provided. These quartz crucibles 5,
The pulling-up mechanism and the heater 7 are the same as those having a conventionally known configuration, and the quartz crucible 5 is rotatable.

A heat shielding mechanism 9 is provided above the silicon melt 6 and close to the melt surface. This heat shielding mechanism 9 has a screen 15. The shape of the screen 15 is such that the upper part of the screen 15 is a circular tube,
The lower part is frustoconical. This lower end opening 15A
Through which the single-crystal silicon rod 8 is pulled upward. In the heat shielding mechanism 9, an outer cover 10 suspended by an outer cover wire 16 is provided between the outer peripheral surface of the silicon single crystal rod 8 and the inner peripheral surface of the screen 5. The shape of the outer cover 10 is substantially a hemisphere. Further, an inner cover 11 is pivotally mounted on the inner side of the outer cover 10 by pins 12. The inner cover 11 is also suspended by the inner cover wire 17. The shape of the inner cover 11 is also substantially quarter hemispherical. The lower end opening 1 is formed from the inner peripheral surface of the screen 15 below the outer cover 10.
The rail 14 is inclined and fixed toward the opening 5A. The outer cover 10 controls the outer cover wire 16 and the inner cover wire 17 up and down,
The slider 13 can slide on the rail 14 via the slider 13 (see FIG. 3). The inner cover 11 can rotate around the pin 12 by immobilizing the outer cover wire 16 and loosening the inner cover wire 17. The heat shielding mechanism 9 is provided with the outer cover 10.
The movement of the inner cover 11 can control the shielding of heat from the silicon melt 6 in the quartz crucible 5.

Further, in this single crystal pulling apparatus 1,
It has a chamber 2 as in the prior art. A shaft 3 rotated by a motor (not shown) is provided at the center of the chamber 2. A substantially hemispherical graphite susceptor 4 is attached to the upper end of the shaft 3. This graphite susceptor 4
, A quartz crucible 5 is detachably held. The pulling mechanism causes the pulling wire 18 to move up and down above the quartz crucible 5 while rotating in the opposite direction to the quartz crucible 5. A silicon single crystal seed crystal (not shown) is attached to the tip of the pulling wire 18 via a seed chuck (not shown). Then, the seed crystal is raised after being immersed in the silicon melt 6. This allows
The silicon single crystal rods 8 grown sequentially from the seed crystal as a starting point are pulled up in an argon atmosphere.

Next, a method for pulling a silicon single crystal using the single crystal pulling apparatus will be described. Prior to pulling, high-purity polycrystalline silicon is placed in quartz crucible 5 and
A small piece of n-type silicon crystal highly doped with antimony is placed. These are all attached to the shaft 3. The inside of the chamber 2 is evacuated by a vacuum device, an argon gas is supplied into the chamber 2, and the inside of the chamber 2 is set to an argon atmosphere of 10 to 20 Torr. The heater 7 is energized to heat the quartz crucible 5 to melt the raw material such as silicon. Next, the seed crystal suspended by the pulling wire 18 is brought into contact with the center of the silicon melt 13. Simultaneously with this contact, the seed crystal is slowly raised while rotating the shaft 3 in one direction at a predetermined crucible rotation speed by a motor and rotating the shaft 3 in the other direction at a predetermined crystal rotation speed by a pulling mechanism. A silicon single crystal rod 8 grows from the seed crystal and is pulled up.

At this time, the heat generated from the silicon melt 6 is transmitted to the top of the silicon single crystal rod 8 and the vicinity of the top by the screen 15 of the heat shielding mechanism 9.
Temperature range for promoting the generation of SF, for example, 850 to 10
In a temperature range of about 50 ° C., the time during which these parts are located is shortened. Next, as shown in FIG.
After pulling up of silicon single crystal rod 8 (after tailing)
The outer cover wire 16 and the inner cover wire 17
And move the outer cover 10 downward. At this time, the slider 13 slides to the lower end of the rail 14.
The inner cover 11 also moves to near the liquid surface of the silicon melt 6 together with the outer cover 10. The outer cover wire 16 is immobilized, and the inner cover wire 17 is loosened. This allows
The inner cover 11 rotates about the pin 12. At this time,
Part of the inner cover 11 overlaps. The tail of the silicon single crystal rod 8 is completely shielded from the heat transmitted from the silicon melt 6. As a result, in the temperature range of about 850 to 1050 ° C. in and around the tail of the silicon single crystal rod 8, the time during which these parts are located is shortened. Therefore, the silicon single crystal rod 8 pulled up by using the single crystal pulling apparatus 1 of the present embodiment does not generate OSF over the whole, and the quality thereof can be improved.

[0013]

As described above, according to the single crystal pulling apparatus according to the present invention, the single crystal rod is not subjected to the heat history in the predetermined temperature range for a long time, so that the OSF in the single crystal rod can be prevented. Generation can be suppressed, and as a result, the quality of the single crystal rod can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a single crystal pulling apparatus according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view of a main part of a single crystal pulling apparatus according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 5 Quartz crucible 6 Silicon melt (crystal melt) 7 Heater 8 Silicon single crystal rod 9 Heat shielding mechanism

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Shinkonai 1-297 Kitabukurocho, Omiya-shi, Saitama Mitsui Materials Co., Ltd. Central Research Laboratory (72) Inventor Junichi Matsubara 3-8 Iwamotocho, Chiyoda-ku, Tokyo No. 16 Inside Mitsubishi Materials Silicon Co., Ltd. (72) Inventor Yasushi Shimanuki 3-8-16 Iwamotocho, Chiyoda-ku, Tokyo Examiner, Mitsubishi Materials Silicon Co., Ltd. Takeshi Isagami (56) References JP-A-63-303887 (JP, A) JP-A 2-140980 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) C30B 1/00-35/00

Claims (1)

(57) [Claims] A quartz crucible for holding the crystal melt; a heater for heating the crystal melt; a pulling mechanism for pulling a single crystal rod from the crystal melt; A shielding member having an opening through which the single crystal rod is pulled up, while shielding the propagating heat, wherein the area of the opening of the shielding member is made variable. Single crystal pulling device.