WO2005007941A1

WO2005007941A1 - An apparatus and method for recharge raw material

Info

Publication number: WO2005007941A1
Application number: PCT/CN2003/000579
Authority: WO
Inventors: Jianzhong Yuan
Original assignee: Jianzhong Yuan
Priority date: 2003-07-18
Filing date: 2003-07-18
Publication date: 2005-01-27
Also published as: CN1788113A; AU2003255078A1; CN1327040C

Abstract

An apparatus and method for recharge raw material in the crystal growth. Use a feed tube to recharge raw material in a crucible. Cover the lower end of the tube with a plate. The plate is made of the same raw material as the charge in the crucible. Load the raw material in the tube, and then lower the tube into the melt in crucible. When the plate is melted, the raw material in the tube is droped into the crucible. It can be recharged using the feed tube after pulling a ingot, sequentially multiple ingots can be grown by using one crucible. In this apparatus and methods, there are not limited for the shape and size of the raw material, and increase the quantity of the raw material with one time. This apparatus and method can improve productivity, product quality and yield. Lowering material consumption, energy and cost.

Description

TECHNICAL FIELD The present invention relates to a device and method for growing crystals, and in particular, to a device and method for growing crystals by repeated feeding. Background technique

1. Method for growing crystals

At present, the most common method for growing crystals is the direct drawing method. For example, more than 95% of single crystal silicon is produced by the CZ method in the world. The direct drawing method is to add a growth raw material in a melt crucible, melt the growth raw material by resistance heating in a single crystal furnace, and grow a whole crystal rod through a seed crystal.

2, the current method of repeated feeding

In the direct drawing method, because a melt crucible is used, and because of the structure of the direct drawing single crystal furnace, most of the crystal rods can only be fed at a time to pull one crystal rod. Only a few companies have adopted re-feeding technology. But they can only use rod-shaped growth materials, or granular growth materials, or small growth materials. The rod-shaped growth raw material is made into a rod-shaped growth raw material, hung by a seed crystal hook, and then put into a melt crucible for melting. Granular growth The raw materials are granules with a diameter of a few millimeters, or small pieces of material are poured into a melt crucible by a device and melted to achieve the purpose of feeding.

In the prior art, Dr. John Holder of MEMC Electronic Materials Co., Ltd. introduced the granular material repetition and mixed feeding method at the 2001 International Conference on Semiconductor Equipment and Materials (SEMICON China), and introduced the United States The purpose of repetitive addition of the granular mixture described in Patent Nos. 5,588,993 and 5,919,303.

The above-mentioned repeated feeding methods are all limited to the use of rods, or granular materials, or small pieces. In fact, the vast majority of production uses lumpy raw materials. Not smashing small pieces. Therefore, the prior art greatly limited the application of repeated feeding.

3. The significance of repeated feeding

a. Repeated feeding can increase the amount of charge in a melt crucible, thereby increasing productivity and reducing Consumables, reduce energy consumption, achieve the goal of increasing production and reducing costs.

b. Repeated feeding can pull several crystal rods in one melt crucible, which further reduces consumables, saves energy, and reduces costs.

Take the growth of single crystal silicon as an example. According to Dr. M Holder of MEMC, the first single crystal silicon rod is drawn. Because more material is added to the melt crucible, the cost can be reduced from 100% to 94% without repeated feeding. When drawing the second single crystal silicon rod, the cost is 74% of the cost without repeated feeding, and the third single crystal silicon rod can reach 60%. This is undoubtedly of great economic value for the global monocrystalline silicon industry with over US $ 10 billion. We know that more than 90% of straight-pull single crystal silicon uses bulk materials as growth raw materials. Therefore, for the production of single crystal silicon, the repeated use of bulk materials can really increase the production capacity and reduce the cost. This example also shows the significance of repeated feeding, especially for block feeding. Summary of the invention

In order to use bulk growth raw materials without restriction on size and shape, the present invention can provide multiple feeding and multiple repeated feedings for one melt crucible, and provides a device and method for growing crystals repeatedly.

The crystal growing device of the present invention mainly includes: a melt crucible 12 for melting growth raw materials, and the melt crucible 12 is placed in a graphite crucible 11 in a graphite heater 10. The feeding tube which is repeatedly fed into the melt crucible 12, and the bottom port of the feeding tube is covered with a bottom plate made of the same raw material as the growing raw material.

In the device of the present invention as described above, the specific method steps of repeatedly adding growing materials to growing crystals are −

1. First, cover the bottom port of the feeding tube with a bottom plate made of the same raw material as the growing raw material;

2. Fill the growth material into the feeding tube;

3. Hang the top of the feeding tube on the seed crystal hook;

4. When there is molten melt in the melt crucible, put the bottom plate of the bottom end of the feeding tube containing the growth raw material into the melt;

5. After the bottom plate is melted, the growth material falls into the melt crucible, and the feeding tube is raised;

6. When all the growth raw materials in the feeding tube fall into the melt crucible, raise the empty feeding tube, and when all the growth raw materials are melted into the melt, put the seed crystals to grow crystals and start pulling the crystals;

7. After drawing a complete crystal rod, repeat the above steps repeatedly. At this point, the above steps can be repeated to draw multiple complete crystal rods.

Obviously, in the above apparatus and method of the present invention, a growth tube is added to the melt crucible with a feeding tube. The material is not limited by whether the growing raw material is blocky, or small, or granular. For a melt crucible, not only can feed more at one time, but also it can be repeatedly fed multiple times. This is of great significance for the production of crystals. The quality of the crystal rods grown is improved by increasing the loading amount at one time. For example, the grown single crystal silicon rod has good resistivity uniformity and high product utilization. In short, feeding with the feeding pipe of the present invention improves the output, reduces the loss, and reduces the cost. Repeatedly adding the growth raw material multiple times, in the same melt crucible, several crystal rods can be drawn. This, of course, greatly reduces consumables, saves energy, and will double the cost. The above-mentioned device and method of the present invention can be applied to a variety of crystals grown by the direct-drawing method. For example, it can be used for crystal growth of silicon, lithium niobate, lithium osmate, sapphire, potassium arsenide and the like. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of repeated feeding with the whole rod in the prior art.

Fig. 2 is a schematic diagram of repeated feeding with granular or small blocks in the prior art.

Figure 3 is a schematic diagram of crystal growth from a melt.

Figure 4 is a schematic diagram of the residual melt in the melt crucible after growing a crystal rod.

Fig. 5 is a schematic diagram of a device for repeatedly feeding with a feeding tube according to the present invention.

FIG. 6 is a schematic diagram of the growth raw material falling into the melt after the bottom plate of the bottom port of the feeding tube is melted. Figure 7 shows the feed tube being lifted upwards, with more growth material falling into the melt.

Fig. 8 shows that after all the feeding tubes are raised out of the liquid surface, the growth raw materials in all the feeding tubes are added to the melt crucible.

Figure 9 shows that when the growth feedstock is repeatedly added once, there is more melt of the growth feedstock in the melt crucible. detailed description

The device and method of the present invention are further described below with reference to the drawings and specific embodiments.

FIG. 1 shows a prior art in which a melt crucible 12 is placed in a graphite crucible 11 in a graphite heater 10. A whole rod-shaped growth raw material 101 is repeatedly fed into the melt crucible 12. A part of the growing raw material in the melt crucible 12 becomes a melt 13. Under the graphite crucible 11, there are heater wires 14 between the graphite heaters 10. FIG. 2 shows that in the prior art, a feeder 201 is used to repeatedly feed granular or small block growth raw material 202 into the melt crucible 12. The granular growth raw material 202 is particles having a diameter of several millimeters.

Fig. 3 shows that all the growth raw materials in the melt crucible 12 are melted into a melt, and crystals will be drawn from the melt.

Fig. 4 shows that after the growth of a crystal rod is completed, some molten material 13 of the growing material always remains in the melting crucible 12.

Fig. 5 is a device for repeated feeding by a feeding tube according to the present invention.

The bottom port of the feeding tube 18 is blocked by a bottom plate 19 composed of the same raw material as the growing raw material. The feed pipe 18 is filled with the growth raw material 15. At the top of the feeding tube 18, a connector 17 is suspended from the seed crystal hook 16. In the figure, the bottom plate 19 of the feeding tube 18 has been placed in the growth raw material melt 13 in the melt crucible 12. The feeding tube 18 may be made of the same material as the melt crucible 12, or a high melting point material having a melting point higher than that of the growing material. Such as quartz, ceramic, platinum, iridium and so on.

Fig. 6 shows that the bottom plate 19 at the bottom of the feeding tube 18 entering the melt crucible 12 in Fig. 5 has been partially melted. In the figure, 21 is a part of the baseplate after being plutonized. A part of the growth raw material 20 has fallen from the feeding tube 18 into the melt crucible 12.

Figure Ί shows that when the bottom plate 19 on the bottom port of the feeding tube 18 is completely melted, more growth raw material 22 flows from the feeding tube 18 into the melt crucible 12 and is melted in the growth raw material melt 13. 18 promotion.

FIG. 8 shows that all the growth raw materials 22 are added to the melt crucible 12 after all the feeding tubes 18 are raised out of the liquid surface.

FIG. 9 shows that when all the growth raw materials in the feeding tube are added to the melt crucible 12, the empty feeding tube 18 has been raised. After the repeated feeding process is completed, the growth raw materials are all melted, and there are more in the melt crucible 12 Growth raw melt.

The specific method steps for repeated feeding with the feeding tube of the present invention are:

First, the method steps of the first furnace charging are:

1. First cover the bottom port of the feeding tube with a bottom plate made of the same raw material as the growing raw material;

2. Fill the growth material into the feeding tube;

3. Charge and melt in the melt crucible according to the conventional method;

4. Hang the top of the feeding tube on the seed crystal hook and wait for the growing material in the melt crucible to melt. Place the bottom plate of the bottom port of the feeding tube into the molten growth raw material melt. After the bottom port bottom plate melts and falls off, the growth raw material in the feeding tube falls into the melt crucible and melts to raise the feeding tube;

5. The raw materials to be grown all fall into the melt crucible, and the empty feeding tube is raised. After all the growing materials are melted, the seed crystals of the growing crystals are put in, and the crystals are then drawn.

Second, the steps for repeated feeding of more than one complete crystal rod are-

1. Cover the bottom port of the feeding tube with a bottom plate made of the same raw material as the growing raw material;

2. Fill the growth material into the feeding tube;

3. After removing a complete crystal rod grown in the single crystal furnace, hang the top of the feeding tube on the seed crystal hook;

4. Maintain the temperature of the melt crucible;

5. Put the feeding tube into the molten growth raw material melt. After the bottom plate of the bottom port melts and falls off, the growth raw material in the feeding tube also falls into the melt crucible and melts to raise the feeding tube;

6. When all the growth materials in the feeding tube fall into the melt crucible, raise the empty feeding tube. After all the growth raw materials are melted, put the seed crystal into the crystal and start to pull the crystal;

7. After pulling a complete crystal rod out, repeat the steps in this second part. Repeat the steps in this second part repeatedly, that is, repeatedly repeat the feeding, to achieve the purpose of drawing multiple crystal rods in a melt crucible.

Claims

Rights request

1. A device for repeatedly adding and growing crystals, mainly comprising: a melt crucible for melting and growing crystal raw materials, and the melt crucible being placed in a graphite crucible in a graphite heater, which is characterized by containing a material for adding growth materials to the melt crucible. The feeding tube, the bottom port of the feeding tube is covered with a bottom plate made of the same raw material as the growing raw material.

2. The method for repeating the device for growing crystals according to claim 1, characterized in that the specific method steps are-

(1) First, cover the bottom port of the feeding tube with a bottom plate made of the same raw material as the growing raw material;

(2) Fill the growth material into the feeding tube;

(3) Hang the top of the feeding tube on the seed crystal hook;

(4) When there is a molten melt in the melt crucible, put the bottom plate of the feeding tube containing the growth raw material into the melt;

(5) After the bottom plate of the bottom end of the feeding tube is melted, a part of the growth raw material falls into the melting crucible, and the feeding tube is lifted;

(6) When all the growing materials in the feeding tube fall into the melt crucible, raise the empty feeding tube, and when all the growing materials are melted into the melt, insert the seed crystals of the crystals to be grown and start pulling the crystals;

(7) After drawing and pulling out a complete crystal rod, repeat the above steps.