JPH0322276Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an FZ method single crystal manufacturing apparatus, and particularly to a bellows protection device of an FZ apparatus equipped with a bellows.

[Prior Art] Conventionally, when manufacturing a semiconductor single crystal by the floating zone method (FZ method), an apparatus as shown in FIG. 5 has been used.

In FIG. 5, 1a is a telescopic upper bellows, 1
b is a lower bellows, 2 is a fixed heating chamber, 3 is a crystal melting section, 4 is a heating coil, 5 is a seed crystal, 6 is a polycrystalline rod, and 7 is a feed screw.

A polycrystalline rod 6 is lowered through a heating coil 4 in a fixed heating chamber 2 to produce a single crystal.

The produced single crystal and raw material polycrystal are lowered by the feed screw 7.
However, since the heating chamber 2 is fixed,
As it descends, the upper bellows 1a contracts and the lower bellows 1b expands. When the production is completed, a new polycrystal is set and the same operation is repeated.

[Problems to be solved by the invention] In this way, the bellows 1a and 1b repeatedly expand and contract. Also, due to the radiant heat from the crystal melting section 3, the temperature of the bellows near the heating chamber becomes around 300°C.
Therefore, deterioration of the bellows is inevitable.

In particular, the lower bellows 1b is constantly exposed to falling and scattering melts from the crystal melting portion 3 in the heating chamber 2, and these melts entering the folds of the bellows
This can damage and damage expensive bellows, shortening their lifespan.

In addition, the inside of the FZ device is normally filled with argon gas, but if the bellows is damaged and the sealing performance is impaired, the physical properties of the single crystal may deteriorate due to the intrusion of outside air impurities, or in some cases, Single crystal production becomes completely impossible.

In order to solve this problem, Japanese Patent Application Laid-Open No. 53-82604 discloses a technique in which a telescoping cylinder is provided inside the bellows to completely protect the inside.

However, the bellows itself is exposed to high temperatures and is susceptible to deterioration.

As described above, the present invention solves problems such as deterioration of expensive bellows at high temperatures, damage due to melt entrapped in the bellows folds, shortened lifespan, resulting deterioration of single crystal physical properties, and risk of production interruption. This was done to solve the problem.

[Means for Solving the Problems] In other words, the present invention provides a single crystal manufacturing apparatus using the FZ method, which has an upper bellows, a lower bellows, and a fixed heating chamber, and a protective tube is provided inside the bellows. The tube is composed of an upper protection tube and a nested lower protection tube, and the lower protection tube is composed of a lower upper protection tube, a lower middle protection tube, and a lower lower protection tube, and the upper protection tube and the lower middle protection tube are It is characterized by having a cooling jacket structure.

The present invention will be explained below based on one embodiment.

[Embodiment] FIG. 1 shows a schematic cross-sectional view of an embodiment of the FZ method single crystal manufacturing apparatus according to the present invention.

In FIG. 1, 8 is an upper protection tube, 9 is a lower upper protection tube, 10 is a lower middle protection tube, and 11 is a lower lower protection tube.

The upper protection tube 8 is cylindrical and has a jacket structure, and is designed to be cooled by water passage.The upper end is open, and the lower end is connected to the lower end of the upper bellows 1a and the fixed heating chamber 2, and is kept airtight with an O-ring 30. , its height is approximately the same as the height when the upper bellows 1a is most contracted, and its thickness is approximately 6 mm. For example, stainless steel (SUS304) can be used as the material.

The lower upper protection cylinder 9 is cylindrical and has a jacket structure, and is designed to be cooled by water passage, and its upper end is connected to the upper end of the lower bellows 1b.
Further, it is connected and fixed to the fixed heating chamber 2, and is kept airtight with an O-ring 30, and a stopper 12 is attached to the lower end. The lower middle protection cylinder 10 is cylindrical,
Stopper 13 at the upper end and stopper 14 at the lower end
is attached.

The lower protection cylinder 11 has a cylindrical shape, has a stopper 15 attached to its upper end, and has its lower end fixed to the pulling furnace main body.

The protection tubes 9, 10, and 11 are disposed inside the lower bellows 1b, and the protection tube 10 is of a telescopic type so that it can slide between the inside of the protection tube 11 and the outside of the protection tube 9. and 10 are locked with stoppers 12 and 13, and the protective tube 10 and the protective tube 11
is designed to be locked by stoppers 14 and 15.

The heights of the protective tubes 9, 10, and 11 are approximately equal, the total height is approximately equal to the height when the lower bellows 1b is fully extended, and the height of each is approximately equal to the height when the lower bellows 1b is fully contracted. The height is approximately equal to the height of

The thickness of the protective tube 9 is approximately 6 mm, and the thickness of the protective tube 1 is approximately 6 mm.
The thickness of 0 and 11 is 3 to 4 mm, and the material may be stainless steel (SUS304), for example.

In this embodiment, the lower protection cylinder has a three-stage structure of upper, middle, and lower stages, but it can also have a two-stage structure, upper and lower.

Next, the jacket of the protective tube will be explained using FIG. 1.

The upper protection tube 8 has a cavity 16 as shown in the figure, and a part of the bottom of the protection tube is filled with cooling water into the cavity 1.
A tube 17 is provided for leading to the opening 1
7a is provided at the bottom of the cavity 16, and a water supply port 17b is provided at the bottom of the upper protection tube 8.

In addition, a drain pipe 18 is provided in another part of the protective cylinder, and its opening 18a is located at the upper part of the cavity 16.
The drain port 18b is provided at the bottom of the protection cylinder.

The cooling water led from the water supply port 17b flows through the opening 17.
When the water enters the upper protective cylinder 8 through the opening 18a and fills the cavity 16, it is led to the drain pipe 18 through the opening 18a and drained through the drain port 18b.

Note that the lower upper protection tube 9 also has a similar structure.

[Function] Figure 2 shows the protection tube 9 at the start of the float zone.
3 shows the state in the middle of implementing the float zone, and FIG. 4 shows the state when the float zone is completed.

At the start of the float zone, the lower bellows 1b is in its most contracted state. Therefore, the protective tubes 9, 1
0 and 11 have shrunk as shown in Figure 2. As the float zone advances, the lower intermediate protection tube 10 and the lower lower protection tube 11 both descend, as shown in FIG. When it begins to descend and completes the float zone, it is stopped by stoppers 14 and 15, as shown in FIG.

The upper protection cylinder 8 remains connected and fixed to the fixed heating chamber 2 from the start of the float zone until the completion of the float zone.

The temperature of the upper protection tube 8 and the upper upper protection tube 9 rises to approximately 300° C. due to radiant heat from the float zone. For this purpose, water is passed through the jackets of the protective tubes 8 and 9 to cool them. By doing this, both the upper bellows 1a and the lower bellows 1b can be prevented from rising in temperature due to radiant heat from the start of the float zone to the completion of the float zone, and the bellows, especially the lower bellows, can be prevented from rising due to radiant heat from the float zone. Molten material that enters the folds of the bellows may damage the expensive bellows as the bellows expands and contracts.
It can be completely prevented from being damaged.

[Effects of the invention] As detailed above, the invention not only completely prevents the upper bellows 1a and the lower bellows 1b from being damaged or shortened in life due to falling and scattering of molten material from the float zone, but also prevents the sealing. This has a great effect in greatly reducing the risk of deterioration in single crystal quality or interruption of production as a result of impurities from the outside air entering the crystal due to poor properties.

Further, as a result of water cooling the upper protection tube and the lower protection tube, there is a great effect of preventing the temperature rise of the upper and lower bellows and preventing deterioration of the bellows.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the FZ method single crystal manufacturing apparatus according to the present invention. FIG. 2, FIG. 3, and FIG. 4 are reference vertical sectional views showing the operating state of the protection tube. FIG. 5 is a longitudinal cross-sectional view of a conventional FZ method single crystal manufacturing apparatus.

Claims (1)

[Scope of utility model registration request] In the FZ method single crystal manufacturing apparatus, which has an upper bellows 1a, a lower bellows 1b, and a fixed heating chamber 2, and a protective tube is provided inside the bellows, the protective tube includes an upper protective tube and a nested lower protective tube. The lower protection tube is composed of a lower upper protection tube 9, a lower middle protection tube 10, and a lower lower protection tube 11, and the upper protection tube 8 and the lower upper protection tube 9 have a cooling jacket structure. Single crystal manufacturing equipment.