JPH06199590A - Device for producing semiconductor single crystal rod - Google Patents

Abstract

PURPOSE:To obtain a large diameter semiconductor single crystal rod few in crystal fault at a low cost by providing the subject device with the flow straighteing cooling cylinder which is formed integrately with the ceiling part of the heating chamber so that it surrounds concentrically the semiconductor single crystal rod being pulled-up. CONSTITUTION:The production device for the semiconductor single crystal rod consisting of the heating chamber 2a accommodating the crucible 5 which houses the fused liq. of a semiconductor and the heater which heats the starting material semiconductor in the crucible 5 and the pulling-up chamber 3 which is placed at the central part of the ceiling part 2b of the heating chamber which covers the opening part of the heating chamber 2a and houses the pulled-up semiconductor single crystal rod is formed as described later. That is, the flow straightening cooling cylinder 25 which extends from the connecting part of the ceiling part 2b of the heating chamber and the pulling-up chamber 3 toward the inside of the heating chamber 2a and surrounds the pulled-up semiconductor single crystal rod is formed integrately with the ceiling part 2b of the heating chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a semiconductor single crystal ingot 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.

Up to now, the apparatus for producing a single crystal ingot by the CZ method has been improved to reduce dislocations and various crystal defects as much as possible and to produce a single crystal ingot at a lower cost. There is.

One of them is that a cooling cylinder is provided inside the heating chamber so as to surround the single crystal rod being pulled, and by efficiently cooling the single crystal rod being pulled, dislocations and crystals are increased even if the pulling speed is increased. Various methods and devices have been proposed to prevent defects and the like. An example of the pulling method and its apparatus provided with such a cooling cylinder is disclosed in JP-A-47-
26,388, Japanese Patent Publication No. 3-35,279 and Japanese Patent Application Laid-Open No. 2-97,481.

In the technique disclosed in Japanese Patent Application Laid-Open No. 47-26388, the lower portion of the pulling chamber is extended to project into the heating chamber, and a small cylinder is provided so as to surround the single crystal rod, and an inert gas is provided. There is disclosed a pulling method and an apparatus for blowing the above from above the pulling chamber. According to this method, the solidification interface is smoothed by the forced cooling of the single crystal ingot to reduce various lattice defects.
However, in the method according to this publication, since the cooling depends only on the forced cooling by the gas, the diameter is 100 m.
The cooling effect is insufficient at present when the diameter of crystals exceeding m and the operation under reduced pressure have become common.

Next, in the technique disclosed in Japanese Patent Publication No. 3-35,279, the structure is a tapered tubular body that coaxially surrounds a single crystal that is being pulled up and the tip of which is close to the melt. , And has a three-layer structure in which the thermal emissivity is specified. In this method and apparatus, heat removal of the tubular body is insufficient because the tapered tubular body is only placed at the entrance of the pulling chamber, and the outer surface of the tubular body is not made of graphite, silicon carbide, or silicon nitride. However, even if a heat insulating layer is provided in the middle, it is difficult to completely prevent the heating effect on the inner surface side.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 2-97,481, the cooling efficiency of the cooling cylinder is improved by providing the refrigerant passage with the tapered cooling cylinder concentrically surrounding the single crystal being pulled. . In this method and apparatus, since the structure is complicated and expensive, it is costly to keep the cooling cylinders of various lengths depending on the pulling conditions, and the cost is increased. SiO adheres easily, and the adhered SiO sometimes drops to cause dislocation of crystals.

[0008]

As described above, various improvements have been made in the conventional method and apparatus for manufacturing a semiconductor single crystal ingot, but in recent years, the diameter of the semiconductor single crystal ingot has been increased and the cost has been reduced. In order to obtain non-defective products, it is still not a satisfactory method and device.

Therefore, an object of the present invention is to provide a semiconductor single crystal ingot producing apparatus for producing a large diameter semiconductor single crystal ingot having few crystal defects at low cost.

[0010]

The above objects are to cover a crucible in which a semiconductor melt is housed and a heating chamber main body containing a heater for heating a raw material semiconductor in the crucible, and an opening of the heating chamber. In a manufacturing apparatus for a semiconductor single crystal ingot, which comprises a heating chamber ceiling and a pulling chamber located in a central portion of the heating chamber ceiling and housing a pulled semiconductor single crystal ingot, the heating chamber ceiling and the pulling chamber An apparatus for producing a semiconductor single crystal rod, characterized in that a rectifying and cooling cylinder extending from the joining portion to the inside of the heating chamber toward the inside of the heating chamber and surrounding the semiconductor single crystal rod being pulled is integrally formed with the ceiling portion of the heating chamber. Achieved by

The present invention is the apparatus for producing a semiconductor single crystal ingot, wherein the rectifying and cooling cylinder is reduced in diameter from the lower portion of the pulling chamber toward the inside of the heating chamber. Also,
In the present invention, the rectification cooling cylinder is formed of at least one material selected from the group consisting of copper, nickel and copper, nickel, titanium, molybdenum, tungsten or copper or nickel coated with a platinum group element. And a semiconductor single crystal ingot manufacturing apparatus. further,
The present invention, graphite, so as to fit inside the rectification cooling cylinder,
An apparatus for producing a semiconductor single crystal ingot, further comprising an internal cooling cylinder made of at least one material selected from the group consisting of silicon carbide and graphite whose surface is coated with silicon carbide.

[0012]

In the semiconductor single crystal ingot manufacturing apparatus of the present invention configured as described above, the semiconductor single crystal that is being pulled is extended toward the inside of the heating chamber from the joint between the ceiling of the heating chamber and the pulling chamber. By forming the rectification cooling cylinder surrounding the rod integrally with the heating chamber ceiling, heat removal of the rectification cooling cylinder is effectively performed by the heating chamber ceiling, so that the semiconductor single crystal rod being pulled is rapidly cooled. can do. At least one selected from the group consisting of high thermal conductivity copper, nickel and copper or nickel or low vapor pressure titanium, molybdenum, tungsten, or copper or nickel coated with a white metal element is used for the rectification cooling cylinder. By being formed of one material, it is possible to prevent contamination inside the chamber.

Further, an inner cooling cylinder made of 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 is fitted inside the rectification cooling cylinder. By combining them, the semiconductor rod can be cooled more efficiently. Then, by reducing the diameter of the rectification cooling cylinder toward the inside of the heating chamber, the internal cooling cylinder can be easily fitted,
Since the diameter of the straightening cooling cylinder is reduced toward the inside of the heating chamber, the contact area with the internal cooling cylinder can be increased, and the diameter of the straightening cooling cylinder and the internal cooling cylinder are reduced. Even if the inner and outer diameter of changes due to thermal expansion,
Since the change can be followed, the heat transfer between the internal cooling cylinder and the rectification cooling cylinder can be kept good, so that the heat removal of the internal cooling cylinder is always performed effectively.

[0014]

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

This single crystal ingot manufacturing apparatus 1 has a member for melting semiconductor raw materials such as silicon and a mechanism for pulling out crystallized silicon. The member for melting silicon is the heating chamber body 2a. Also, the heating chamber main body 2a and the heating chamber ceiling 2b are housed in a chamber 2 composed of a heating chamber ceiling 2b, and a mechanism for pulling a silicon single crystal is provided inside and outside the pulling chamber 3. ing.

A crucible 5 containing molten silicon is provided in the heating chamber main body 2a, and the crucible 5 is supported by a rotary shaft 4 of a drive unit (not shown) so as to be rotatable and movable up and down. . The drive device raises the crucible 5 by the amount corresponding to the liquid level lowering in order to compensate for the liquid level lowering accompanying the pulling of the silicon single crystal ingot S, and also keeps the crucible 5 at a predetermined rotation speed for stirring the silicon melt. Rotate with. The rotary shaft 4 penetrates 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 bad temperature conditions. The crucible 5 is a quartz crucible 5b as in the conventional case.
And a crucible 5a made of graphite for protecting the same.

A heater 6 for melting silicon is arranged on the side wall of the crucible 5 so as to surround the periphery thereof. The heater 6 is provided outside the heater 6.
A heat insulating member 11 is provided so as to surround the periphery of the heating chamber main body 2a, which is prevented from being radiated directly to the heating chamber main body 2a. The heater 6 and the heat insulating member 11 are attached to the support base 24.

In the lifting chamber 3, the wire hoist 1
No. 0 has one end attached thereto, and a pulling wire 7 penetrating through the top wall of the pulling chamber 3 is provided. At the lower end of the pulling wire 7, a chuck 9 for holding a seed crystal is attached. There is. Wire hoist 1
In 0, the silicon single crystal rod S gradually growing to the lower end side of the seed crystal is pulled up according to its growth rate, and at the same time, the crucible 5 is always rotated in the opposite direction to the rotation direction.

Argon gas is introduced into the interior of the chamber 2 from a gas inlet 12 provided in the pulling chamber 3 and flows through the interior of the chamber 2. At the atmospheric pressure or a pressure lower than the atmospheric pressure by several Torr during pulling of the single crystal rod. It is kept and discharged from the gas outlet 13. In order to circulate the argon gas in this way, SiO generated inside the chamber due to melting of silicon adheres to various members inside the chamber,
This is to prevent the contamination of the silicon melt and the formation of dislocations in the crystal due to the dropping onto the silicon melt, and to cool the silicon single crystal ingot being pulled by the argon gas.

The heating chamber body 2a and the heating chamber ceiling portion 2b are made of stainless steel, and are cooled by water through a cooling pipe. Further, the heating chamber ceiling 2b is integrally formed with the heating chamber 2b so as to surround the single crystal ingot from the lower part of the pulling chamber 3 toward the inside of the heating chamber main body 2a. A rectifying / cooling cylinder 30 having a diameter reduced toward the inside of 2a is provided. This straightening cooling cylinder 30
Is a material with good thermal conductivity such as copper, nickel and copper, nickel or titanium, molybdenum, tungsten with low vapor pressure,
It is formed of a material such as copper or nickel coated with a metal such as a platinum group element, and is preferably made of graphite having excellent thermal conductivity and plated with nickel. Does not react with graphite when the internal cooling cylinder 25 is fitted, and since nickel has a lower vapor pressure than copper, it contaminates the interior of the chamber 2 even if it is at a high temperature. Never.

Since this rectifying cooling cylinder has an integral structure with the ceiling portion of the heating chamber which is water-cooled, sufficient heat is removed, and the internal cooling cylinder 25 described below is used.
Also, it is possible to suppress the temperature rise of the argon gas flowing along the single crystal rod S that is being pulled inside the inner cooling cylinder 25. Further, since the material of the rectification cooling cylinder 30 is nickel-plated as described above, the radiant heat inside the chamber is reflected at the outer portion of the rectification cooling cylinder, so that the temperature rise of the rectification cooling cylinder itself is small. End

Further, the length of the rectification cooling cylinder 30 is equal to or larger 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 this 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, the raw silicon mass before melting is placed in the crucible 5. This is because the bulk of the raw material silicon comes into contact with the bulk of the raw material silicon when it is put in, and the raw material silicon is contaminated, or the chamber ceiling portion 2b is not tightened, which causes a problem. Further, inside the rectifying cooling cylinder 30, a removable internal cooling cylinder 25 made of graphite that extends toward the melt interface of the crucible 5 is provided.
Is fitted in the rectified cooling cylinder 30 whose diameter is reduced. The internal cooling cylinder 25 is shielded from the radiant heat from the heater 6 and the silicon melt by the rectification cooling cylinder 30 so that the single crystal rod S being pulled can be rapidly cooled.

Since the internal cooling cylinder 25 can be freely removed, it is possible to change the quenching region of the single crystal rod during pulling by collecting the internal cooling cylinders 25 of various lengths and thicknesses and exchanging them appropriately. It is possible to obtain a silicon single crystal of desired quality. That is, the internal cooling cylinder 2
When 5 is extended to near the melt interface, the silicon single crystal ingot S being pulled can be rapidly cooled immediately after being pulled, and a silicon single crystal of the quality of the top of the single crystal ingot can be obtained.
When the internal cooling cylinder 25 is shortened and the distance from the melt interface is increased, the internal cooling cylinder 25 is gradually cooled immediately after pulling, so that a silicon single crystal having the quality of the bottom of the single crystal rod can be obtained.

Further, the graphite used as the material of the internal cooling cylinder 25 is installed near the melt interface and does not fall into the melt even if SiO adheres to it, thereby preventing contamination of the melt and dislocation of crystals. It never happens.

The results of manufacturing a silicon single crystal using the semiconductor single crystal ingot manufacturing apparatus according to the present invention having the above-described structure are shown in the case where only the rectification cooling cylinder 30 is used, and the inside cooling cylinder is provided inside the rectification cooling cylinder. Table 1 shows the case of manufacturing by fitting 25. For comparison, when a silicon single crystal ingot is manufactured by using the semiconductor single crystal ingot manufacturing apparatus without a rectification cooling tube according to the present invention, and instead of the rectification cooling tube, a graphite cooling tube is simply used as a heating chamber ceiling part. Table 1 also shows the case where a silicon single crystal ingot was manufactured by hanging it from 2b. The crucible used at this time had a diameter of 16 inches, and the manufactured single crystal rod had a nominal diameter of 6 inches.

[0026]

[Table 1]

As can be seen from Table 1, the silicon single crystal ingot produced by the semiconductor single crystal ingot producing apparatus of the present invention has a high dislocation-free single crystal pulling rate and a high pulling rate.

[0028]

As described above, in the semiconductor single crystal ingot manufacturing apparatus of the present invention, the metal rectification cooling cylinder is integrated with the water-cooled heating chamber ceiling so that the rectification cooling cylinder itself can be removed. It is excellent in heat and can suppress the temperature rise of the argon gas flowing inside, and at the same time can reflect the radiant heat from the raw material semiconductor melt, so that the single crystal rod can be cooled more rapidly. Furthermore, it is possible to rapidly cool the single crystal rod being pulled from directly above the raw material melt by fitting a removable graphite internal cooling cylinder inside. And
Since this graphite internal cooling tube is removable,
It is possible to manufacture a semiconductor single crystal ingot of desired quality without incurring a large cost increase, even if those having various lengths and shapes are always provided.

[Brief description of drawings]

FIG. 1 is a view for explaining a semiconductor single crystal ingot 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 part, 3 ... pulling chamber,
4 ... Rotary axis, 5 ... Crucible,
5a ... Graphite crucible, 5b ... Quartz crucible,
6 ... Heater, 7 ... Wire,
9 ... Chuck, 10 ... Wire hoist, 11 ... Insulation material, 12 ...
Gas inlet port, 13 ... Gas outlet port, 20 ... Separation mechanism, 25 ...
Rectifying cooling cylinder, 30 ... Internal cooling cylinder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masamichi Okubo 3434 Shimada, Higashi, Yamaguchi Prefecture, Nittatsu Electric Co., Ltd. Within the development headquarters

Claims (4)

[Claims] 1. A heating chamber main body containing a crucible containing 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, and a heating chamber ceiling. In a manufacturing apparatus for a semiconductor single crystal ingot, which is located in a central portion of the heating chamber and has a pulling chamber for accommodating a pulled up semiconductor single crystal ingot, in a heating chamber inside from a joint portion between the heating chamber ceiling and the pulling chamber. 1. A semiconductor single crystal ingot manufacturing apparatus, characterized in that a rectifying and cooling cylinder that extends toward the front and surrounds the semiconductor single crystal ingot being pulled is integrally formed with the ceiling portion of the heating chamber. 2. The semiconductor single crystal ingot manufacturing apparatus according to claim 1, wherein at least a part of the rectifying and cooling cylinder has a diameter reduced toward the inside of the heating chamber. 3. The straightening cooling cylinder is made of copper, nickel and copper,
It is formed of at least one material selected from the group consisting of copper or nickel coated with nickel, titanium, molybdenum, tungsten, or a platinum group element, according to any one of claims 1 to 2. The semiconductor single crystal ingot manufacturing apparatus described. 4. A graphite selected from the group consisting of graphite fitted inside the rectifying cooling cylinder and extending from the rectifying cooling cylinder further into the heating chamber, silicon carbide and graphite whose surface is coated with silicon carbide. The semiconductor single crystal rod manufacturing apparatus according to claim 1, further comprising an internal cooling cylinder formed of at least one material.