JPS5848368Y2 - Crucible equipment for melting semiconductor materials - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a crucible device for melting semiconductor materials.

A quartz crucible 1 and a graphite crucible 3 as shown in FIG. 1 are used to melt a semiconductor material such as silicon for refining it into a single crystal.

A quartz crucible 1 is for containing and melting a semiconductor material 2.

The graphite crucible 3 has a concave portion having a substantially similar external shape to the quartz crucible 1.

Usually, the quartz crucible 1 has a circular cross section and a vertical cross section of approximately U.
It is composed of letters.

Into such a quartz crucible 1 a semiconductor material 2 is placed as described above.

Such a quartz crucible 1 is housed in a recessed portion of a graphite crucible 3.

At that time, the side wall surface of the concave part of graphite crucible 3 and the quartz crucible 1
Provide a slight gap between the outer wall surface and the outer wall surface.

The quartz crucible 1 and graphite crucible 3 are heated in a melting furnace using a high frequency induction device, resistance heating, etc.
The semiconductor substance 2 is melted and refined into a single crystal by a pulling operation.

The gap that existed between the outer wall surface of the quartz crucible 1 and the inner wall surface of the concave portion of the graphite crucible 3 before the semiconductor material 2 was melted caused by the deformation of the quartz crucible 1 due to the heat of melting the semiconductor material 2, and disappears due to volumetric expansion due to heat.

That is, the quartz crucible 1 and the graphite crucible 3 are in close contact with each other.

This phenomenon occurs because the volumetric expansion of graphite due to heat is significantly larger than that of quartz.

Another major reason is that the quartz crucible softens and is deformed outward by the weight of the melt.

Furthermore, due to the difference in thermal expansion coefficients between graphite and quartz glass, the quartz crucible 1 and graphite crucible 3 are brought into a more closely fitted state during cooling.

Therefore, a large stress is generated between the quartz crucible 1 and the graphite crucible 3, and there is a risk that one of them will be damaged during the cooling stage.

Even if it were not damaged, it would be extremely difficult to remove it from the quartz crucible 1 and graphite crucible 3.

Therefore, in the past, various efforts have been made to solve these difficulties.

For example, a proposal has been made to divide the graphite crucible 3 into two or more parts in the vertical or horizontal direction to make it easier to remove the quartz crucible 1.

However, in the past, the graphite crucible was simply divided in the vertical direction, which had the disadvantage that the divisions tended to separate from each other during use.

For example, when the graphite crucible 3 and the quartz crucible 1 are heated near the melting point of the semiconductor material 2 during pulling of a single crystal of the semiconductor material 2, the quartz crucible 1 is softened, and as a result, the molten material of the semiconductor material The quartz crucible 1 and graphite crucible 3 are pushed outward and expanded by their own weight.

For this reason, the divided surfaces of the graphite crucible 3 tend to move away from each other, and as a result, voids are created between the divided surfaces.

Such voids cause radiant heat to be transferred directly from the heated object to the quartz crucible 1, thereby changing the heat transfer conditions and having an adverse effect on the quality of the crystal.

Another drawback is that the crucible device cannot be stabilized during rotation and pulling.

The purpose of this invention is to provide a crucible device for melting semiconductor materials that eliminates the drawbacks seen in the prior art as described above and allows the dividing surfaces to be separated during use, making it easier to maintain good processing conditions. It is in.

The present invention is a graphite crucible that houses a quartz or Si3N4 crucible for storing and melting a semiconductor material, and the graphite crucible has a concave portion that is substantially similar in external shape to that of the quartz or Si3N4 crucible. It is divided into two or more pieces in the vertical direction by the first and second dividing planes.

Further, the first dividing plane intersects with the second dividing plane.

Preferably, the two second dividing planes are substantially parallel to each other,
One first dividing surface is formed between both ends of these second dividing surfaces.

Furthermore, each divided body divided by the first and second dividing planes may be constructed line-symmetrically with respect to the central axis of the graphite crucible, so that the first dividing plane passes through the central axis of the graphite crucible, and It is desirable that the first and second dividing planes are nearly perpendicular.

Hereinafter, preferred embodiments of this invention will be described with reference to the drawings.

2 and 3 show a first embodiment of this invention.

The graphite crucible 3 is constructed such that a quartz crucible 1 as shown in FIG. 1 is housed in a recessed portion 3a thereof.

The inner wall surface of the concave portion 3a has a configuration similar to the outer shape of a quartz crucible.

The cross-sectional shape of the graphite crucible 3 is circular.

The vertical cross-sectional shape of the concave portion 3a is approximately (1-shaped).

Further, the outer wall side surface of the graphite crucible 3 has a cylindrical shape.

A tray portion can be provided on the bottom surface of the graphite crucible 3.

In some embodiments, such a receiver may omit the dish portion.

Now, in the crucible devices according to these inventions, the graphite crucible 3 is divided into two or more pieces in the vertical direction.

In the embodiment of FIGS. 2 and 3, the graphite crucible 3 is divided into two parts.

A first dividing surface D1 extending from the center O of the graphite crucible 3 toward the outer periphery intersects with a second dividing surface D2 extending from the outer periphery toward the concave portion 3a.

In the illustrated example, as can be seen from Figure 2,
The first dividing plane D1 and the second dividing plane D2 intersect each other at almost right angles, and the first dividing plane D1 and the second dividing plane D1
and D2 are set to approximately the same length, and as a whole, the first and second dividing planes D1 and D2 correspond to two sides of a right-angled isosceles triangle.

In the example shown in FIG. 2, one first dividing surface Dl and two second dividing surfaces D2 have a shape close to Z.

Note that the inner wall surface of the graphite crucible 3 extends downward in a straight line from the upper end to point P1, and is a curved surface from point P1 to the center.

As a result, when viewed in plan, the second dividing plane D2 becomes linear as shown in FIG.

When viewed from the side, point P as shown in Figure 3
1 to point P2, the second dividing plane D2
appears in a curved line.

4 and 5 show other embodiments of this invention.

In this embodiment, the graphite crucible 3 has a concave portion 3a having a substantially similar external shape to the quartz crucible, and is divided into three parts in the vertical direction.

The first dividing surface D1 extending from the center O of the graphite crucible 3 toward the outer periphery and the second dividing surface D2 extending from the outer periphery toward the concave portion 3a intersect at a substantially right angle as in the first embodiment.

Furthermore, the first and second dividing planes D1 and D2 are set to have substantially equal lengths, and both correspond to two sides of a right-angled isosceles triangle.

Then, the three first dividing planes D1 are arranged at the same angle.
distributed in the direction.

That is, the angle between the first dividing planes D1 is set to 120°.

Since the crucible device according to this invention is constructed as described above, the area of the dividing plane is significantly increased, and a remarkable effect is obtained in that the divided bodies of the graphite crucible are difficult to separate from each other during use.

That is, the mutual contact area of the divided bodies of the graphite crucible increases, and as a result, it becomes easier to stably hold the divided bodies in a predetermined shape.

As a result, the occurrence of gaps between the dividing surfaces of the graphite crucible is minimized, and radiant heating from direct heat from the heating element can be prevented.
The undesirable effects of the conventional method can be kept to a minimum.

Local heating of the quartz crucible can be avoided, temperature distribution can be kept uniform during use, and as a result, good pulling conditions can be ensured.

By dividing the graphite crucible, the quartz crucible can be accurately accommodated in the graphite crucible in the appropriate state even if there are variations in the external shape of the quartz crucible.

Furthermore, it is possible to sufficiently cope with deformation of the quartz crucible that occurs due to melting.

Conversely, it becomes extremely easy to interiorize the inner wall surface of the graphite crucible 3.

In other words, flexibility is increased between quartz crucibles and graphite crucibles.

In addition, by dividing the graphite crucible in this way, there was no damage to the crucible, and as a result, the number of times it could be used was significantly increased.

In addition, taking out the quartz crucible has become extremely easy, improving work efficiency.

In addition, there is no need to provide a gap between the quartz crucible and graphite crucible, and since both crucibles can be assembled in close contact with each other before melting, heat conduction to the graphite crucible is extremely good, and the side of the quartz crucible due to melting is There is also little deformation of the wall surface.

In particular, if the first dividing plane and the second dividing plane of the graphite crucible are almost perpendicular, the centrifugal force will be effectively dispersed when the crucible device is rotated, and the graphite crucible's dividing bodies will always have a wide dividing plane. This ensures good contact.

Such an effect is maximized when the first dividing plane and the second dividing plane intersect at approximately right angles and are set in a line-symmetrical shape.

Note that this invention is not limited to the above-described embodiments, but includes various other modifications.

For example, instead of a quartz crucible, a Si3N4 crucible may be used.

The first dividing plane does not need to pass through the central axis of the graphite crucible.

The first and second dividing planes may be obtuse angles or acute angles.

Further, as shown in FIGS. 6 to 9, the intersection of the first and second dividing planes may be rounded to avoid concentration of stress.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the outer fence showing a conventional crucible device for melting semiconductor materials, FIG. 2 is a plan view showing an example of the crucible device for melting semiconductor materials according to the present invention, and FIG. 3 is a vertical cross-sectional view thereof. FIG. 4 is a plan view showing another embodiment of the present invention, and FIG. 5 is a longitudinal sectional view thereof. 6 and 7 are a plan view and a sectional view showing another embodiment, and FIGS. 8 and 9 are a plan view and a sectional view showing still another embodiment. 1...Quartz crucible, 2...Semiconductor material, 3...Graphite crucible, 3a...Concave portion, Dl...Graphite crucible A first dividing plane from the center to the outer periphery, D2... A second dividing plane extending from the outer periphery of the graphite crucible to the concave portion, O... The center of the graphite crucible.

Claims (5)

[Scope of utility model registration request] (1) Quartz or S for containing and melting semiconductor materials
In a graphite crucible containing an i3N4 crucible, the graphite crucible has a concave portion substantially similar to the outer shape of the quartz or Si3N4 crucible, and is divided into two or more parts in the vertical direction by first and second dividing surfaces. 1.
A crucible device for melting a semiconductor material, characterized in that a dividing plane intersects with the second dividing plane. (2) A crucible for melting a semiconductor material according to claim 1, wherein the two second dividing planes are substantially parallel to each other, and one first dividing plane is formed on both end faces of the second dividing planes. Device. (3) The semiconductor material melting device according to claim 1, wherein each of the divided trees divided by the first and second dividing planes is constructed line-symmetrically with respect to the central axis of the graphite crucible. Crucible device. (4) The crucible device for melting semiconductor materials according to claim 1, wherein the first dividing plane passes approximately through the central axis of the graphite crucible. (5) The crucible device for melting a semiconductor material according to claim 1, wherein the first and second dividing planes are substantially orthogonal.