JP2575428B2 - Powder supply pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a powdery material supply pipe, particularly to a supply pipe for continuously supplying polycrystalline silicon into a crucible for a single crystal pulling apparatus.

[Prior art] A crucible is provided in a vacuum melting furnace of a single crystal pulling apparatus, and a silicon polycrystal is heated in this crucible,
It becomes a silicon melt. In order to keep the concentration of impurities in the silicon melt constant as the single crystal is pulled, polycrystalline silicon particles are supplied into the crucible.

[Problems to be Solved by the Invention] However, since the replenished silicon polycrystalline powder has a particle size distribution of 100 μm to 3 mm, some of the fine particles are directly discharged after being discharged from the supply pipe. Instead of dropping on the liquid surface of the melt, it floats in the air and reaches near the solid-liquid interface of the single crystal. As a result, the uniformity of the characteristics of the grown single crystal deteriorates. In addition, some of the coarse particles of the powder and granules do not dissolve quickly and reach the vicinity of the solid-liquid interface as a solid.

An object of the present invention is to prevent a powder or a granular material to be supplied into a crucible for a single crystal pulling apparatus from floating in the air near a solid-liquid interface of a single crystal to be pulled, and directly into the crucible. It is an object of the present invention to provide an apparatus for supplying a granular material capable of dropping onto a liquid surface of a melt.

[Means for Solving the Problems] According to the present invention, the object is to supply silicon polycrystal powder to a crystal component melt contained in a quartz crucible for a single crystal pulling apparatus. A tube oriented downward above the crucible, and a solid-liquid interface of a single crystal from which a space between the tube and the liquid surface of the melt is to be raised in cooperation with an inner peripheral surface of the crucible. A quartz isolating member fixed to the tube for isolation, the isolating member is a plate-shaped member having a developed rectangular shape and arranged vertically, and each of both side edges of the plate-shaped member is provided. Is close to the inner peripheral surface of the crucible with a small interval, the upper edge of the plate-shaped member is located above the open end of the tube, and the lower edge of the plate-shaped member is In contact with or slightly above the level of the melt in the crucible This is achieved by a powder supply pipe characterized in that:

[Operation] According to the present invention, the particles to be supplied into the crucible for the single crystal pulling apparatus are prevented from floating in the air near the solid-liquid interface of the single crystal to be pulled, and are directly prevented. It is possible to provide an apparatus for supplying a granular material that can be dropped onto a liquid surface of a molten liquid in a crucible.

The separating member according to the present invention is composed of a plate-like member having a developed shape of a rectangle and arranged vertically, and each of both side edges of the plate-like member approaches the inner peripheral surface of the crucible at a small interval. The upper edge of the plate-shaped member is located above the open end of the tube, and the lower edge of the plate-shaped member is in contact with or slightly above the liquid level of the melt in the crucible. It is located in.

This can prevent the particles supplied from the tube from floating in the air near the solid-liquid interface, and also prevent the particles suspended on the liquid surface from moving to the solid-liquid interface. obtain.

Further, the molten material contained in the plate-like member can be maintained at a high temperature by heat from a heater to be provided around the peripheral side of the crucible, and as a result, the granular material supplied from the tube is quickly melted. Can be done.

The plate-shaped member may be composed of a half-cylindrical body cut along a longitudinal surface including a diameter.

When the inner diameter of the crucible is 16 inches, the radius of curvature of the half-cylindrical body is preferably 80 mm or less, particularly preferably 40 mm.

The plate-shaped member may be formed of a half-split body of an elliptical ring-shaped body cut along a longitudinal surface including a long axis.

The distance between the open end of the tube according to the invention and the liquid level is preferably less than 80 mm, particularly preferably 20 mm.

Specific Examples Hereinafter, the present invention will be described in more detail with reference to specific examples shown in the drawings.

In one embodiment of the supply tube of the invention according to FIG. 1, a crucible 1 is surrounded around a cylindrical quartz crucible 1 arranged under vacuum pressure in a vacuum melting furnace for a single crystal pulling device. An annular heater (not shown) is provided. The inner diameter of the crucible 1 is 16 inches. The heat generated by the heater dissolves the polycrystalline silicon contained in the crucible 1,
It becomes a silicon melt 2 as a crystal component melt. In order to keep the impurity concentration of the melt 2 constant, the supply means of the silicon polycrystal powder (not shown) supplies the silicon polycrystal powder via a quartz supply pipe 3 having a diameter of 10 mm. The liquid is supplied to the liquid level 4 as indicated by an arrow 5. The distal end of the tube 3 is disposed vertically, and is located near the peripheral side of the crucible 1. The distance between the open end of the tube 4 and the liquid surface 4 is 20 mm. Particle size distribution of supplied granules is 100
From microns to 3 millimeters.

The quartz cylinder half 6 as an isolating member is
The tube 3 is fixed to the distal end of the tube 3 by a quartz rod 7 disposed above the tube 3 so as to receive the tube 3. The fixing of the pipe 3 and the rod 7 and the fixing of the half-split body 6 and the rod 7 are performed by welding.

The radius of curvature of the half-split body 6 is preferably 40 millimeters, the depth is 50 millimeters, and the plate thickness is 3 millimeters. The diameter of the bar 7 is 5 millimeters.

The half-split body 6 is arranged such that the distance between each of the side edges of the half-split body 6 and the inner peripheral surface of the crucible 1 is small, and the lower edge of the half-split body 6 is in contact with the liquid surface 4 or It is arranged to be located slightly above. Thereby, the rotation of the crucible 1 can be allowed, and the powder and granular material discharged from the tube 3 flows in the air and on the liquid level 4 to the outside of the half-split body 6, that is, to the solid-liquid interface of the single crystal to be pulled (not shown). Floating can be prevented and, in addition, the melt 2 contained in the half-pieces 6 can be kept at a high temperature by the heat from the above-mentioned heater, so that the granular material supplied from the pipe 3 is Can be rapidly dissolved.

Next, another example of the supply pipe of the present invention will be described with reference to FIG. 2, the same members as those in FIG. 1 are denoted by the same reference numerals, and their structures and functions will not be described.

The bent plate 8 made of quartz as an isolating member in the supply pipe of FIG. A circular arc portion 9 disposed coaxially with and vertically to each of the circular arc portions 1 is provided integrally with each of both side ends of the circular arc portion 9 and is inclined toward the outer peripheral side of the circular arc portion 9 to be horizontal. It is composed of flat plate portions 10 and 11 having a length in the direction of 30 mm, a depth of 40 mm and a thickness of 3 mm. The arc plate 10 is suitably fixed to the tube 3 by means of a bar 7. The distance between the crucible 1 and the arc plate 10 is 20
Millimeters.

Here, the arc plate 9 is arranged such that the distance between each side edge of the flat plate portions 10 and 11 and the inner peripheral surface of the crucible 1 is small, and whether the lower edge of the curved plate 8 is in contact with the liquid surface 4. Alternatively, it is arranged to be located slightly above.

According to the curved plate 8, in addition to the same effect as the effect of the supply pipe of FIG. 1, since the arc plate 9 is provided along the circumferential direction of the crucible 1, when the crucible 1 rotates. , The molten liquid 2 can smoothly turn around the curved plate 8.

[Effects of the present invention] According to the present invention, it is possible to prevent a powdery substance to be supplied into a crucible for a single crystal pulling apparatus from floating in the air to near a solid-liquid interface of the single crystal to be pulled. In addition, it is possible to provide a supply device of a granular material that can be directly dropped on a liquid surface of a molten liquid in a crucible.

[Brief description of the drawings]

FIG. 1 is a perspective view of one specific example of the supply pipe of the present invention, and FIG. 2 is a perspective view of another specific example of the supply pipe of the present invention. 1 ... crucible, 2 ... silicon polycrystalline melt, 3 ... supply tube, 6 ... half-cylindrical body.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuo Wakasa 378 Oguni-cho, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Prefecture Inside the Oguni Plant of Toshiba Ceramics Corporation 63-42164 (JP, U)

Claims (3)

(57) [Claims] A tube oriented downwardly above the crucible to supply silicon polycrystalline powder to a crystal component melt contained in a quartz crucible for a single crystal pulling apparatus; A quartz separating member fixed to the tube so as to isolate a space between the tube and the liquid surface of the melt from a solid-liquid interface of a single crystal to be pulled in cooperation with an inner peripheral surface of the crucible; The separating member is formed of a plate-like member having a developed shape of a rectangle and arranged vertically, and each of both side edges of the plate-like member approaches the inner peripheral surface of the crucible at a small interval. The upper edge of the plate-shaped member is located above the open end of the tube, and the lower edge of the plate-shaped member is in contact with or slightly above the liquid level of the melt in the crucible. Powder supply pipe characterized by being located in the. 2. The supply pipe according to claim 1, wherein said plate-like member is formed of a half-cylindrical body cut along a longitudinal surface including a diameter. 3. The supply pipe according to claim 1, wherein said plate-like member is made of a half-split body of an elliptical ring-shaped body cut along a longitudinal plane including a major axis.