WO2018099334A1

WO2018099334A1 - Method for continuously drawing monocrystalline silicon rod by synchronously carrying out crystal drawing, material feeding, material melting and impurity separation

Info

Publication number: WO2018099334A1
Application number: PCT/CN2017/112963
Authority: WO
Inventors: 袁玉平; 袁佳斌
Original assignee: 江苏拜尔特光电设备有限公司
Priority date: 2016-11-30
Filing date: 2017-11-25
Publication date: 2018-06-07
Also published as: CN106544726A

Abstract

The present invention relates to a method for continuously drawing a monocrystalline silicon rod by synchronously carrying out crystal drawing, material feeding, material melting and impurity separation. The method comprises: filling a material into a crucible; heating the material to melt the material; synchronously carrying out crystal drawing, material feeding, material melting and impurity separation; drawing, by means of a drawing head on a drawing device, the obtained material to form a rod having a specified length or a certain length; continuing to carry out crystal drawing, material feeding, material melting and impurity separation by means of another drawing head on the drawing device; and repeating the drawing until the quality of the silicon rod approaches a standard requirement due to an impurity impact, shutting down a furnace, and cleaning the furnace. By means of the present invention, crystal drawing costs can be greatly reduced, and the quality of the monocrystalline silicon rod can also be improved.

Description

Method for continuously drawing single crystal silicon rod by pulling crystal, feeding, chemical material and separating impurities simultaneously

[0001] The present invention relates to a method for drawing a single crystal silicon rod, and more particularly to a method for continuously drawing a single crystal silicon rod.

[0002] With the development of society, the people's life is constantly improving, and the demand for electricity is increasing. Traditional coal and petrochemical raw materials generate not only non-renewable resources but also cause serious pollution to the atmosphere. It has been recognized by people all over the world, especially solar power is the most ideal energy source in clean energy. However, due to the high production cost, it has seriously restricted its large-scale development.

technical problem

[0003] At present, the method of drawing a single crystal silicon rod is a step-by-step method, and the so-called step method is: charging - chemical material - pulling crystal - pulling the available material - stopping the furnace - taking the rod - cleaning the furnace, are Independently, it has problems such as low production efficiency, low quality of single crystal silicon rods, and high production cost.

Problem solution

Technical solution

OBJECT OF THE INVENTION: The object of the present invention is to overcome the deficiencies in the prior art and to provide a crystal pulling, feeding, chemical, and separating impurities which can greatly reduce the cost of pulling crystals and improve the quality of single crystal silicon rods. A method of continuously drawing a single crystal silicon rod simultaneously.

[0005] Technical Solution: In order to solve the above technical problem, a method for continuously drawing a single crystal silicon rod by pulling crystal, feeding, chemical, and separating impurities simultaneously according to the present invention includes the following steps:

[0006] (1) charging in the crucible;

[0007] (2) heating the material;

[0008] (3) pulling, feeding, chemical, and separating impurities are simultaneously performed;

[0009] (4) drawing a rod of a predetermined length or a length by a pulling head on the pulling device; [0010] (5) by converting another pulling head on the pulling device to continue pulling, feeding, chemicalizing, separating impurities;

[0011] (6) Repeated drawing until the quality of the silicon rod is close to the standard requirement due to the influence of impurities, and then the furnace is shut down and the furnace is cleaned.

[0012] In the step (3), the level of the material in the crucible is maintained at the level of the material level after the complete materialization in the step (2).

[0013] In the step (3), polysilicon and a master alloy are added in the same manner.

[0014] in the step (3), the weight of the pull-out device is provided by the weighing device on the pulling device, and then the PLC sends a command to the feeding device to perform synchronous and equal-feeding, so as to pull out the quality of the crystal and The quality of the added silicon material is consistent.

[0015] In the step (4), the two lifting heads on the pulling device are repeatedly switched.

Advantageous effects of the invention

Beneficial effect

[0016] Compared with the prior art, the present invention has the significant advantages of:

[0017] (1) High efficiency: Synchronized by pulling crystal, feeding, chemical, and separating impurities, saving the time of the previous charging, chemical, crystal rod cooling, shutdown, and cleaning, the pulling speed is obviously improved, pulling The stability of the crystal is also obviously improved. Through two lifting heads that can be repeatedly switched, the cooling and the rod are synchronously performed with the pulling crystal, which greatly saves the daytime, and the production capacity is 2.5 times or more of the current single crystal furnace;

[0018] (2) High quality: Single crystal rods drawn by conventional methods, the resistance distribution of the single crystal rods is uneven, generally the head is high, the tail is low, and the gap is large, because the conventional method is single crystal furnace pulling The mother alloy is added in one step before the crystal, and then some of the mother alloy will precipitate downward during the pulling process due to the long draw between the turns, so the resistance to the tail will be low, and the method is stepwise in the drawing process. The addition of the master alloy is consistent in the amount of consumption and the amount of addition. Therefore, the head and the tail of the single crystal rod which is pulled by the method of the present invention are substantially identical, and the quality of the silicon rod is greatly improved;

[0019] (3) Good stability: In the present invention, since the pull crystal is consistent in mass and the quality of the added silicon material, the liquid crystal surface position is constant, and the temperature fluctuation of the crystal liquid surface is very high. Small, long-crystal bismuth will be very stable, and the conventional method of pulling the crystal, the stability of the liquid crystal surface is adjusted by the diameter of the crystal rod and the ratio of the diameter of the crucible, the accuracy is poor, so the stability of the liquid surface not good;

[0020] (4) Low cost: the unit cost of drawing a single crystal silicon rod by the method of the invention is lower than that of the conventional method for drawing single crystal silicon The unit cost of the rod should be saved by more than 50%, mainly in the electricity cost and quartz crucible and thermal field loss and labor cost; the electricity bill is mainly reflected in the need to stop the furnace and separate materials, and lose a lot of heat during the furnace shutdown process. From high temperature to low temperature, and then need to heat the low temperature to high temperature, the separate material needs to be carried out under high power, which wastes electrical energy and is easy to damage the equipment. The thermal field is easily aged after repeated high temperature and low temperature conversion. In addition, a large amount of quartz crucible is saved. The consumption of quartz crucible is one tenth of that of the conventional method, and the service life of the thermal field is more than five times higher than that of the conventional method. The labor cost is also significantly reduced, saving the furnace. The cost of drawing the finished single crystal silicon rod per ton in the traditional method is 75,000 yuan (the electricity cost is 0.8 yuan per degree), and the cost of drawing the finished single crystal silicon rod per ton by the method of the invention is 30,000 yuan (the electricity cost is 0.8 yuan per Calculation of the degree) The single crystal furnace produced by the method of the present invention can save a cost of 2.16 million yuan per year compared with the conventional single crystal furnace.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] The present invention will be further described below in conjunction with the embodiments.

[0022] A method for continuously drawing a single crystal silicon rod by pulling crystal, feeding, chemical, and separating impurities simultaneously according to the present invention, which comprises the following steps,

[0023] (1) charging in the crucible;

[0024] (2) heating the material;

[0025] (3) pulling, feeding, chemical, separating impurities simultaneously: feeding is the same as adding polysilicon and mother alloy; pulling and feeding simultaneously, is to pull out the crystal through the weighing device on the lifting device The quality is then sent to the feeding device through the PLC to perform synchronous and equal feeding, so that the quality of the pulled crystal is consistent with the quality of the added silicon material, so that the liquid level in the crucible remains in the step (2). After the liquid level of the material;

[0026] (4) drawing a rod of a predetermined length or a length by a pulling head on the pulling device;

[0027] (5) continuing to pull crystal, feed, material, and separate impurities by switching another pulling head on the pulling device;

[0028] (6) Repeated drawing until the quality of the silicon rod is close to the standard requirement due to the influence of impurities, and then the furnace is shut down and the furnace is cleaned.

[0029] In the step (4), the two lifting heads on the pulling device are repeatedly switched.

[0030] In the present invention, the crystal pulling, the feeding, the material, and the separation of impurities are simultaneously performed, thereby saving the previous charging and chemicalization. The material, the crystal rod is cooled, the furnace is shut down, and the furnace is cleaned. Through two lifting heads that can be repeatedly switched, the cooling and the rod are synchronized with the pulling crystal, which greatly saves the daytime and gradually adds during the drawing process. The mother alloy has the same consumption and the added amount. Therefore, the single crystal rod which is pulled by the method of the invention has the same resistance head and tail, which greatly improves the quality of the silicon rod, and the crystal quality and the addition of silicon material are extracted in the crystal pulling crucible. The quality is consistent. Because the liquid crystal surface position is constant, the temperature fluctuation of the long crystal liquid surface is very small, and the crystal growth time is very stable. Generally, the quality of the raw material is no problem, and the continuous drawing can be more than one month.

The present invention provides an idea and a method. The method and the method for implementing the technical solution are numerous. The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art do not leave In the premise of the principles of the present invention, a number of improvements and refinements can also be made. These improvements and refinements should also be considered as the scope of protection of the present invention, and various components that are not explicitly defined in this embodiment can be implemented by the prior art.

Claims

The invention relates to a method for continuously drawing a single crystal silicon rod which is simultaneously carried out by pulling crystal, feeding, chemical material and separating impurities, and is characterized in that it comprises the following steps:

(1) charging in the crucible;

(2) heating the material;

(3) Pulling crystals, feeding materials, chemical materials, and separating impurities simultaneously;

(4) Pulling a rod of a specified length or length by a pulling head on the pulling device;

(5) Continue to pull crystal, feed, chemical, and separate impurities by switching another lifting head on the lifting device;

(6) Repeat the drawing until the quality of the silicon rod is close to the standard due to the influence of impurities, then stop the furnace and clean the furnace.

The method for continuously drawing a single crystal silicon rod by pulling crystal, feeding, chemicalizing, and separating impurities according to claim 1, wherein: in the step (3), the liquid level in the crucible is always Maintain the level of the material after complete materialization in step (2).

The method for continuously drawing a single crystal silicon rod by pulling crystal, feeding, chemicalizing, and separating impurities according to claim 1, wherein: in the step (3), adding polysilicon and a mother alloy to the same layer .

The method for continuously drawing a single crystal silicon rod by pulling crystal, feeding, chemicalizing, and separating impurities according to claim 1, wherein: in the step (3), the scale on the pulling device is The weight device provides the quality of the pull-out crystal, and then sends a command to the feeding device through the PLC to perform synchronous and equal-feeding, so that the quality of the pulled-out crystal is consistent with the quality of the added silicon material.

The method for continuously drawing a single crystal silicon rod simultaneously with pulling, feeding, chemicalizing, and separating impurities according to claim 1, wherein: in the step (4), two on the pulling device The lifting head repeats the switching.