JPH04202084A - Single crystal producing apparatus - Google Patents

Abstract

PURPOSE:To prevent the deposits to a shielding means and to prevent deposition by discharging an inert gas from the surface on the furnace body side of the shielding member which shields the furnace body and a growth chamber. CONSTITUTION:A crucible 52 packed with a melt 54 is disposed in the furnace body 50 and an isolation valve 12 is erected to communicate the furnace body 50 and the growth chamber 62. A seed crystal 58 is immersed into the melt 54 and is pulled up to grow the single crystal A. After the single crystal A of a prescribed length is pulled up into the growth chamber 62, the isolation valve 12 is turned in an arrow (a) direction to shield the growth chamber 62 and the furnace body 50. After the inert gas is discharged from a discharge port 14 on the furnace body 50 side front face of the isolation valve 12, the growth chamber 62 is released to the atm. and the single crystal A is taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for manufacturing a semiconductor single crystal using the Czochralski method.

<Conventional technology> As a manufacturing method for semiconductor single crystals such as silicon, a seed crystal is immersed in a melt filled in a crucible, and the seed crystal is pulled upward while rotating to grow a single crystal under the seed crystal. The ski method (cZ method) is known.

As a method for improving operational productivity when manufacturing single crystals using this Czochralski method, Japanese Patent Application Laid-Open No. 2-9782
A single crystal manufacturing apparatus as shown in FIG.
FIG. 4 shows a schematic diagram of this single crystal manufacturing apparatus.

The single crystal manufacturing apparatus (hereinafter referred to as the manufacturing apparatus) shown in FIG. The single crystal A is continuously grown by pulling up the seed crystal 58 into the growth chamber 62 above by the pulling shaft 60 while rotating it (or while the crucible 52 is also rotating in the opposite direction).

In this manufacturing apparatus, the crucible 52 is composed of an outer tank 52a and an inner tank 52b, and a polycrystalline 66 as a raw material is supplied to the outer tank 52a from a long polycrystal supply device 64 according to the growth capacity of the single crystal A. The structure is such that the amount of the melt 54 can be kept constant and a large amount of single crystal A can be continuously produced.

Here, when the single crystal A has grown to a predetermined length, it is necessary to take out the single crystal A from the growth chamber 62. For this purpose, a shielding member is used to shield the furnace body 50 and the growth chamber 62. An isolation valve 68 must be provided. In other words, in this manufacturing equipment, a single crystal A of a predetermined length is used.
After pulling the single crystal A into the growth chamber 62, the isolation valve 68 is turned in the direction shown by arrow a to shield the furnace body 50 and the growth chamber 62, and the growth chamber 62 is opened to atmospheric pressure to grow the single crystal A. It is something to take out.

Furthermore, as shown in FIG. 5, in Japanese Patent Application Laid-open No. 1-246191, a valve storage section 70 is provided at the lower end of the growth chamber 62, and the isolation valve 72 is slid in the direction of the arrow inside this storage chamber. A manufacturing apparatus is disclosed in which the furnace body 50 and the growth chamber 62 are shielded by doing so.

<Problems to be Solved by the Invention> Incidentally, in such a single crystal manufacturing apparatus, gases generated from the melt may occur on the surface of the isolation valve 68 (72) on the side of the furnace body 50 or on the inner wall of the furnace body 50. There is a problem in that a deposit 74 such as SiO is formed and deposited, and this deposit 74 falls into the crucible 52. When such deposits 74 enter the crucible 52,
This deposit 74 becomes suspended on the surface of the melt 54, and when the single crystal A is pulled, it adheres to the single crystal and causes polycrystallization.

However, in the manufacturing apparatus shown in FIG. 4, such deposits 74 tend to form on the surface of the isolation valve 68 on the furnace body 50 side.
There is a problem in that the deposits 74 fall when the tube is closed or blocked. Furthermore, in a device to which the isolation valve 72 as shown in FIG. 5 is applied, there is less deposit 74 attached to the isolation valve 72 than in the example shown in FIG. Furnace body 50 due to vibration due to time slide
Deposits attached to the inner wall may fall off, and as the use continues, the isolation valve 72 may become damaged.
There is a problem in that deposits 74 are formed on the surface of the crucible 52 and fall into the crucible 52.

An object of the present invention is to solve the problems of the prior art described above, and to prevent the formation and deposition of deposits on the shielding means (isolation valve) between the furnace body and the growth chamber, and to always maintain a good semiconductor. An object of the present invention is to provide a single crystal manufacturing apparatus that can manufacture a single crystal and is therefore superior in manufacturing costs for semiconductor single crystals.

Means for Solving the Problems> In order to achieve the above object, the present invention provides the steps of: melting polycrystals and supplying the melt to a crucible disposed in a furnace;
A single crystal is pulled into a growth chamber from this melt, the single crystal is grown, and after pulling the single crystal of a predetermined length, it is possible to take out the single crystal by shielding the furnace body and the growth chamber with a shielding member. The present invention provides a single crystal manufacturing apparatus comprising: a means for discharging an inert gas from a surface of the shielding member on the furnace body side;

Further, it is preferable that the shielding means has a convex shape on the furnace body side.

Hereinafter, the single crystal manufacturing apparatus of the present invention will be explained in detail.

FIG. 1 shows a schematic cross-sectional view of an example of a single crystal manufacturing apparatus according to the present invention. The basic configuration of the single-crystal manufacturing apparatus shown in FIG. 1 is the same as the single-crystal manufacturing apparatus shown in FIG. is omitted.

The single crystal manufacturing apparatus 10 (hereinafter referred to as the manufacturing apparatus 10) shown in FIG. The single crystal A is grown by rotating the crystal 58 (or the crucible 52 as well) and pulling it upward, and the polycrystal 66 is grown in the outer tank 52 of the crucible 52 according to the growth capacity of the single crystal A.
By charging the melt 54 to a constant amount, it is possible to continuously produce a large amount of single crystal A.

Furthermore, in the manufacturing apparatus 10 according to the present invention, the growth chamber 62
The isolation valve 12 is provided as a shielding member that shields the furnace body 50 and the growth chamber 62 when taking out the single crystal A of a predetermined length that has been pulled up.

That is, in the illustrated manufacturing apparatus 10, the isolation valve 12 is operated as shown in FIG. 2a (FIG.
The furnace body 50 and the growth chamber 62 are in communication with each other. On the other hand, single crystal A
When the single crystal A grows to a predetermined length, the single crystal A is pulled into the growth chamber 62, and then the isolation valve 12 is rotated in the direction of arrow a and placed at the position shown in FIG. 2b (dotted line in FIG. 1). The furnace body 50 and the growth chamber 62 are shielded.
In this state, the growth chamber 62 is released to atmospheric pressure, and the single crystal A is taken out from the growth chamber 62. After the extraction is completed, the isolation valve 12 is again set to the position shown in FIG. 2a, the furnace body 50 and the growth chamber 62 are communicated with each other, and continuous growth is performed by starting pulling the single crystal A again.

Here, in the manufacturing apparatus 10 according to the present invention, the furnace body 5
The isolation valve 12, which is a means for shielding between the growth chamber 62 and the growth chamber 62, is configured to exhaust inert gas from the surface on the furnace body 50 side. The furnace body 50 side of the valve 12 has a convex shape.

As mentioned above, in a semiconductor single crystal manufacturing apparatus having an isolation valve, one of the factors that hinders the growth of a good single crystal is the presence of melt on the surface of the isolation valve on the side of the furnace body 50 or on the inner wall of the furnace body 50. SiO, etc. contained in the gas generated from 54 adheres and accumulates, and this is deposited in the crucible 5.
When the single crystal A grows, this deposit 74 adheres to the single crystal A and causes polycrystallization.

In the manufacturing apparatus 10 of the present invention, by discharging inert gas from the surface of the isolation valve 12 on the furnace body 50 side, gas containing SiO etc. (hereinafter referred to as SiO gas) generated from the melt 54 is removed. This prevents contact with the isolation valve 12 and prevents the deposits 74 from adhering to the isolation valve 12. In the illustrated manufacturing apparatus 10, an inert gas supply means (not shown) is connected to the isolation valve 12 to discharge this inert gas.
Contact of the SiO gas to the isolation valve 12 is prevented by discharging the inert gas from the discharge port 14 formed on the surface of the furnace body 50 of No. 2, for example, as shown in FIG.

Therefore, according to the single crystal manufacturing apparatus of the present invention, polycrystalization can be prevented and semiconductor single crystals such as silicon single crystals can always be manufactured in good quality. It is also possible to reduce costs.

There is no particular limitation on the amount of inert gas discharged, and the amount that can suitably prevent SiO gas from coming into contact with the surface of the isolation valve 12 is determined by the shape and size of the isolation valve 12, as well as the discharge port 14 formed. It may be determined as appropriate depending on the shape, number, size, etc. Similarly, there are no particular limitations on the shape, number, size, or position of the discharge ports 14.

There is no particular limitation on the inert gas that can be applied, and any inert gas that is used as an atmospheric gas for the production of normal semiconductor single crystals can be used. Furthermore, any of various known methods can be applied to the inert gas supply means.

The method of discharging inert gas from the surface of the isolation valve 12 applied to the present invention is not limited to the method of discharging the inert gas from the discharge port 14 formed on the surface of the isolation valve 12 on the furnace body 50 side as in the illustrated example. , for example, by providing a nozzle on the surface of the isolation valve 12 on the furnace body 50 side to spray an inert gas onto the surface of the isolation valve 12. Various methods can be applied as long as it is possible to suitably prevent contact with the surface.

The inert gas may be discharged constantly or only when necessary.

According to the studies of the present inventors, by discharging the inert gas only when the isolation valve 12 shields the furnace body 50 and the growth chamber 62, preferably from immediately after the completion of pulling the single crystal to immediately before restarting. , the formation and deposition of deposits 74 can be largely prevented.

In the illustrated manufacturing apparatus 10, as a preferred embodiment, the isolation valve 12 on the furnace body 50 side has a convex shape. With such a configuration, the pressure of SiO gas on the isolation valve 12 can be weakened, and adhesion of SiO, etc. to the isolation valve 12 can be more preferably prevented.

The shape of the convex shape is not particularly limited, and various shapes are applicable, but a curved surface like the illustrated example or a spherical shape is preferable because pressure can be dispersed more appropriately. Further, the amount of convexity is not particularly limited, but is preferably about 15 to 20 mm at the maximum position.

Although the single crystal manufacturing apparatus according to the present invention has been described in detail above, the present invention is not limited thereto, and various improvements and changes may be made without departing from the gist of the present invention. Of course.

<Example> Hereinafter, the present invention will be explained in more detail by giving specific examples of the present invention.

A silicon single crystal was manufactured using the manufacturing apparatus 10 of the present invention shown in FIG.

The applied isolation valve 12 has a diameter of 250 m.
m, has a spherical shape that is convex by a maximum of 16 mm on the furnace body 50 side, and has one discharge port 14 with a diameter of 3 mm on the side of the furnace body 50.
Six pieces were formed as shown in FIG. 3, and argon gas was supplied at 60 fL/min using a feeder not shown.

Using the manufacturing apparatus 10 of the present invention as described above and a conventional manufacturing apparatus having a similar configuration except for applying a normal isolation valve, when the length of the single crystal A becomes 1 m, an isolation valve is installed. The operation of closing the chamber, taking out the single crystal, and pulling the single crystal again after taking it out was repeated.

FIG. 6 shows the probability of polycrystallization of the single crystal A due to the deposits 74 falling into the crucible 52 and adhering to the single crystal A in each manufacturing apparatus.

From the results shown in FIG. 6, the production apparatus of the present invention can reduce the probability of polycrystallization to less than half,
Furthermore, it can be seen that the increase in polycrystallization can be suppressed even when the single crystal is repeatedly pulled.

From the above results, the effects of the present invention are clear.

<Effects of the Invention> As explained in detail above, the single crystal manufacturing apparatus of the present invention having the above-mentioned predetermined configuration has the following features: Since the shielding means has a means for discharging inert gas from the surface on the furnace body side, gas containing SiO etc. generated from the melt is prevented from coming into contact with the shielding means.
It is possible to prevent 0 etc. from adhering. Also,
Preferably, by forming the furnace body side surface of the shielding means into a convex shape, the pressure of the gas generated from the melt against the shielding means can be weakened, and adhesion of SiO, etc. to the shielding means can be more preferably prevented.

Therefore, by applying the single crystal manufacturing apparatus of the present invention, Si can be deposited in the crucible from the shielding means that shields the furnace body and the growth chamber.
There is very little chance that deposits such as O will fall, and a good semiconductor single crystal can always be produced. Further, since there is no contamination of deposits into the crucible, the yield can be improved and the manufacturing cost of semiconductor single crystals can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a single crystal manufacturing apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view showing the vicinity of the isolation valve of the single crystal manufacturing apparatus shown in FIG. 3 is a plan view showing the furnace body side of the isolation valve of the single crystal manufacturing apparatus shown in FIG. 1. FIG. FIG. 4 is a schematic cross-sectional view showing an example of a conventional single crystal manufacturing apparatus. FIG. 5 is a conceptual diagram showing another example of the vicinity of the isolation valve of a conventional single crystal manufacturing apparatus. FIG. 6 is a graph showing the probability of polycrystallization of a single crystal in the single crystal manufacturing apparatus of the present invention and the conventional single crystal manufacturing apparatus. Explanation of symbols 10...Single crystal production equipment, 12.68.72...Isolation valve, 14
... Discharge port, 50 ... Furnace body, 52 ... Crucible, 54 ... Melt, 56 ... Chuck, 58 ... Seed crystal, 60 ... Pulling shaft, 62 ...・Growth chamber, 64... Polycrystal supply device, 66... Polycrystal, 70... Valve housing part, 74... Deposit, A... Single crystal

Claims (1)

[Claims] (1) While melting the polycrystal, supply the melt to a crucible placed in the furnace, pull the single crystal from the melt into the growth chamber, grow the single crystal, and pull the single crystal of a predetermined length. After that, the single crystal manufacturing apparatus is configured to be able to take out the single crystal by shielding the furnace body and the growth chamber with a shielding member, wherein an inert gas is introduced from a surface of the shielding member on the furnace body side. A single crystal production apparatus characterized by having a means for discharging.