JP3220542B2 - Semiconductor single crystal rod manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a semiconductor single crystal rod by the Czochralski method.

[0002]

2. Description of the Related Art A single crystal rod manufactured by the Czochralski (hereinafter abbreviated as CZ) method is used for manufacturing a semiconductor single crystal used for manufacturing various integrated circuits, particularly a silicon single crystal.

[0003] Up to now, a single crystal rod manufacturing apparatus by the CZ method has been greatly improved in order to minimize dislocations and various crystal defects, and to manufacture a single crystal rod at lower cost. I have.

[0004] One of them is to provide a cooling cylinder inside the heating chamber so as to surround the single crystal rod being pulled up, and to efficiently cool the single crystal rod being pulled up, so that even if the pulling speed is increased, dislocations or crystals are generated. Methods and apparatuses have been proposed that do not cause defects or the like. As a pulling method and a device provided with such a cooling cylinder, for example, JP-B-3-35,2
There is one disclosed in Japanese Patent Publication No. 79.

In the technique disclosed in Japanese Patent Publication No. 3-35,279, a single crystal being pulled is coaxially surrounded, and its tip is a tapered tubular body which is close to the melt, and its structure is thermal conductivity and heat radiation. It has a three-layer structure with specific rates. In this method and apparatus, the outer surface of the tubular body is made of graphite, silicon carbide, or silicon nitride having a high emissivity, so that the tip of the cooling cylinder extends to the vicinity of the raw material semiconductor melt and cools the single crystal rod being pulled. However, if the heat removal of the cooling cylinder itself is insufficient, the vicinity of the raw material semiconductor melt is heated to a high temperature. Rather, the cooling cylinder is formed of graphite or the like, and exhibits a heater-like effect. In some cases, the single crystal rod being pulled may be heated. For this reason, in the technology of this publication, the temperature rise of the cooling cylinder is suppressed by providing the heat insulating layer in the middle of the cooling cylinder. However, there is a problem that the function of the cooling cylinder cannot be eliminated. In particular, when the heat capacity of a high-temperature source such as a raw material melt or a heater inside a single crystal rod manufacturing apparatus becomes large as well as a single crystal rod due to an increase in diameter of the single crystal rod, it is necessary to sufficiently remove heat from the cooling cylinder itself.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a semiconductor single crystal rod manufacturing apparatus for manufacturing a large-diameter semiconductor single crystal rod which suppresses a temperature rise of the rectifying cooling cylinder itself and has few crystal defects. The purpose is to:

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to cover a crucible accommodating a semiconductor melt, a heating chamber main body containing a heater for heating a raw material semiconductor in the crucible, and an opening of the heating chamber. A heating chamber ceiling portion, a pulling chamber portion located at a central portion of the heating chamber ceiling portion for storing the pulled semiconductor single crystal rod, and a joining portion between the heating chamber ceiling portion and the pulling chamber portion, inside the heating chamber. In the apparatus for manufacturing a semiconductor single crystal rod provided with a rectifying cooling cylinder surrounding the semiconductor single crystal rod during pulling, the rectifying cooling cylinder is formed of a metal outer cooling cylinder and an outer cooling cylinder. Consists of an internal cooling cylinder made of at least one material selected from the group consisting of graphite to be fitted, silicon carbide and graphite coated on the surface with silicon carbide It is achieved by a semiconductor single crystal ingot production device which is a heavy structure.

According to the present invention, the outer cooling cylinder is formed of at least one material selected from the group consisting of copper, nickel and copper or nickel coated with copper, nickel, titanium, molybdenum, tungsten or a white metal element. A semiconductor single crystal rod manufacturing apparatus.

[0009]

The semiconductor single crystal rod manufacturing apparatus of the present invention constructed as described above extends from the junction between the heating chamber ceiling and the pulling chamber toward the inside of the heating chamber, and pulls the semiconductor single crystal during pulling. The rectifying cooling cylinder surrounding the rod has a double structure consisting of a metal outer cooling cylinder and an internal cooling cylinder fitted inside the outer cooling cylinder, so that a metal,
For example, an outer cooling cylinder formed of a metal having a high thermal conductivity, such as copper, nickel or copper, nickel, titanium, molybdenum, tungsten, copper or nickel coated with a white metal element, is made of a material semiconductor melt or a heater. To prevent the single crystal rod being heated from being heated by reflecting the radiant heat of the rectifying cooling cylinder itself, and to sufficiently remove the heat of the internal cooling cylinder fitted inside. Can be. And by forming the internal cooling cylinder from at least one material selected from the group consisting of graphite having excellent emissivity, silicon carbide and graphite whose surface is coated with silicon carbide, Can efficiently absorb the radiant heat of the semiconductor rod and cool the semiconductor rod.
As described above, since the outside of the internal cooling cylinder is fitted to the metal external cooling cylinder, the heat removal is efficiently performed,
The temperature rise of the argon gas flowing inside the internal cooling cylinder is suppressed, and the gas cooling effect is enhanced.

Further, by reducing the diameter of the outer cooling cylinder and the inner cooling cylinder toward the inside of the heating chamber, the inner cooling cylinder can be easily fitted, and the outer cooling cylinder and the inner cooling cylinder can be brought into contact with each other. Even if the inner and outer diameters of the outer cooling cylinder and the inner cooling cylinder change due to thermal expansion due to the reduced diameter, the inner cooling cylinder and the outer cooling cylinder can follow the change. The heat transfer effect of the internal cooling cylinder is not impaired because the heat transfer property of the internal cooling tube can be kept good.

The length of the outer cooling cylinder and the inner cooling cylinder is
It is not necessarily the same length, preferably, the internal cooling cylinder formed of graphite or the like is extended to just above the raw material semiconductor melt, and the outer cooling cylinder made of metal is set to about 100 mm or more from the raw semiconductor melt. Is good. This is because even if graphite or silicon carbide is placed directly above the source semiconductor melt, for example, when the source semiconductor is silicon, even if SiO coming out of the source semiconductor melt adheres, it falls and contaminates the melt. This is because, in the case of metal, if SiO adheres, it may fall and contaminate the melt.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an apparatus for manufacturing a semiconductor single crystal rod according to the present invention.

The apparatus 1 for manufacturing a single crystal rod has a member for melting a semiconductor raw material, for example, silicon, a mechanism for pulling up crystallized silicon, and the like. The heating chamber main body 2a and the heating chamber ceiling 2b are separable by a separation mechanism 20, and a mechanism for pulling a silicon single crystal is provided inside and outside the pulling chamber 3. ing.

A crucible 5 for accommodating molten silicon is provided in the heating chamber main body 2a. The crucible 5 is supported by a rotating shaft 4 of a driving device (not shown) so as to be rotatable and vertically movable. . The driving device raises the crucible 5 by an amount corresponding to the lowering of the liquid level in order to compensate for the lowering of the liquid level due to the pulling up of the silicon single crystal rod S. Rotate with. The rotating shaft 4 penetrates through the heating chamber main body 2a, but is held by a special bearing in order to maintain airtightness inside and outside the chamber and to be used under extremely poor temperature conditions. The crucible 5 is made of quartz crucible 5b as in the prior art.
And a graphite crucible 5a for protecting the same.

A heater 6 for melting silicon is disposed on the side wall of the crucible 5 so as to surround the periphery thereof. Outside the heater 6, a heater 6
A heat insulating member 11 for preventing heat from being directly radiated to the heating chamber main body 2a is provided so as to surround the periphery thereof. Note that the heater 6 and the heat insulating member 11 are attached to a support 24.

The lifting chamber 3 includes a wire hoisting machine 1
0 is provided with a pull-up wire 7 which is inserted through the top wall of the pull-up chamber 3 and is suspended therefrom. At the lower end of the pull-up wire 7, a chuck 9 for holding a seed crystal is mounted. I have. Wire hoisting machine 1
Numeral 0 pulls up the silicon single crystal rod S that gradually grows on the lower end side of the seed crystal in accordance with the growth rate or the like, and at the same time, constantly rotates the crucible 5 in the opposite direction to the rotation direction.

The inside of the chamber 2 is supplied with an argon gas through a gas inlet 12 provided in the pulling chamber 3 and circulates therethrough. During the pulling of the single crystal rod, the pressure is maintained at atmospheric pressure or a low pressure of about several Torr. , Gas outlet 13
Is discharged from The argon gas is circulated in this manner because SiO generated inside the chamber due to the melting of silicon adheres to various members inside the chamber, and contamination of the silicon melt due to the falling of the SiO 2 onto the silicon melt. This is for preventing dislocation of the crystal and cooling the silicon single crystal rod being pulled by the argon gas.

The heating chamber main body 2a and the heating chamber ceiling 2b are made of stainless steel, and are water-cooled through a cooling pipe. The heating chamber 2b is placed on the heating chamber ceiling 2b from the lower part of the pulling chamber 3 toward the inside of the heating chamber main body 2a so as to surround the single crystal rod. An outer cooling cylinder 30 having a diameter reduced toward the inside, and an inner cooling cylinder 25 fitted to the outer cooling cylinder.
Rectifying cooling cylinder having a double structure is provided. The outer cooling cylinder 30 is formed of a material such as copper or nickel coated with a metal such as copper, nickel and copper, nickel, or titanium molybdenum, tungsten or a low-metal element having a low vapor pressure, which has good heat conductivity. Preferably, it is formed of copper plated with nickel or platinum so that it does not react with graphite when the internal cooling cylinder 25 made of graphite is fitted. Further, copper has excellent thermal conductivity, and nickel and platinum have lower vapor pressures than copper, so that even inside the chamber 2 where the temperature becomes high, the inside of the chamber 2 is not contaminated.

Since the internal cooling cylinder 25 is sufficiently discharged, the temperature rise of the argon gas flowing along the single crystal rod S while the inside of the internal cooling cylinder 25 is being pulled can be suppressed. . Further, since the material of the outer cooling cylinder 30 is plated with copper, nickel, or platinum as described above, the outer portion of the outer cooling cylinder reflects the radiant heat inside the chamber 2, so that the cooling cylinder 30 itself is reflected. The temperature rise of the steel can be reduced.

The length of the outer cooling cylinder 30 is not less than the crystal diameter of the single crystal rod S, and is 300 to 300 mm from the silicon melt interface.
It is desirable to set it to about 100 mm. If the length is shorter than the crystal diameter, the radiant heat from the crystal rod S cannot be sufficiently removed, while if it is closer to the melt interface than 100 mm, SiO adheres and drops and melts. The liquid may be contaminated.

Since the internal cooling cylinder 25 can be freely removed, the quenching area of the single crystal rod during pulling can be changed by having various lengths and thicknesses of the internal cooling cylinder 25 and replacing them appropriately. Thus, it becomes possible to obtain a silicon single crystal of a desired quality. That is, the internal cooling cylinder 2
In the case where 5 is extended to near the melt interface, the silicon single crystal rod S during pulling can be rapidly cooled immediately after pulling, and a silicon single crystal of the top quality of the single crystal rod can be obtained,
When the internal cooling cylinder 25 is shortened and the distance from the melt interface is increased, cooling is performed gradually immediately after the pulling, and a silicon single crystal having a quality on the bottom side of the single crystal rod is obtained.

The graphite used as the material of the internal cooling cylinder 25 does not fall into the melt even if it is placed near the melt interface and SiO adheres to the melt without causing contamination of the melt or dislocation of crystals. Does not occur.

Table 1 shows the results of the single crystal pulling rate and the crystal defect generation rate when a silicon single crystal was manufactured using the semiconductor single crystal rod manufacturing apparatus according to the present invention configured as described above. Also, for comparison, as a rectifying cooling cylinder,
Table 1 also shows a case where a rectifying cooling cylinder made of metal is used and a case where a rectifying cooling cylinder made of only graphite is used. In this case, the crucible used had a diameter of 16 inches, the manufactured single crystal rod had a nominal diameter of 6 inches, and the lower part of the cooling cylinder was extended to 70 mm from the silicon melt interface. Was.

[0024]

[Table 1]

As can be seen from Table 1, the silicon single crystal rod manufactured by the semiconductor single crystal rod manufacturing apparatus according to the present invention has a low crystal defect occurrence rate and can increase the pulling speed.

[0026]

As described above, in the semiconductor single crystal rod manufacturing apparatus of the present invention, the rectifying cooling cylinder has a double structure of an outer cooling cylinder made of metal and an inner cooling cylinder made of graphite or the like.
Since the rectifying cooling cylinder itself is excellent in heat removal, the temperature rise of the argon gas flowing inside can be suppressed, and the radiant heat from the raw material semiconductor melt can be reflected, so that the single crystal rod can be cooled more rapidly. Further, by fitting the internal cooling cylinder made of graphite inside, it is possible to rapidly cool the single crystal rod being pulled from just above the raw material melt.

[Brief description of the drawings]

FIG. 1 is a view for explaining a semiconductor single crystal rod manufacturing apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor single crystal rod manufacturing apparatus, 2 ... Chamber, 2a ... Heating chamber main body, 2b ...
Heating chamber ceiling, 3 ... pulling chamber,
4 ... rotary axis, 5 ... crucible,
5a: graphite crucible, 5b: quartz crucible,
6 ... heater, 7 ... wire,
9: chuck, 10: wire winding machine, 11: heat insulating material, 12:
Gas inlet 13 Gas outlet 20 Separation mechanism 25
Internal cooling cylinder, 30 ... Outer cooling cylinder.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-286793 (JP, A) JP-A-4-89388 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00

Claims (2)

(57) [Claims] 1. A heating chamber body containing a crucible accommodating a semiconductor melt and a heater for heating a raw material semiconductor in the crucible; a heating chamber ceiling covering an opening of the heating chamber; The pulling chamber portion, which is located at the central portion of the ceiling portion and accommodates the pulled semiconductor single crystal rod, extends from the junction between the heating chamber ceiling portion and the pulling chamber portion toward the inside of the heating chamber, during the pulling. In a semiconductor single crystal rod manufacturing apparatus provided with a rectifying cooling cylinder surrounding a semiconductor single crystal rod, the rectifying cooling cylinder has a metal outer cooling cylinder, and graphite, silicon carbide, and a surface fitted inside the outer cooling cylinder. Is a double structure comprising an internal cooling cylinder formed of at least one material selected from the group consisting of graphite coated with silicon carbide. Semiconductor single crystal rod manufacturing equipment. 2. The metallic outer cooling cylinder is made of copper, nickel and at least one material selected from the group consisting of copper, nickel, titanium, molybdenum, tungsten or copper or nickel coated with a white metal element. The semiconductor single crystal rod manufacturing apparatus according to claim 1, wherein: