CN210177001U - Crystal pulling furnace doping device - Google Patents

Abstract

The utility model provides a crystal pulling furnace doping device, which belongs to the technical field of polycrystalline silicon or monocrystalline silicon production. The crystal pulling furnace comprises a doping pipe, an isolating valve and a doping material filling assembly, wherein one end of the doping pipe is fixedly connected with a crystal pulling furnace platform, the doping material filling assembly is connected with the other end of the doping pipe, and the isolating valve is arranged on the doping pipe and used for isolating the doping material filling assembly from the crystal pulling furnace platform. The doping material filling assembly comprises a doping material storage tank, and an inert gas replacement pipe fitting and a pressure stabilizing pipe fitting which are arranged on the doping material storage tank. During doping operation, the isolating valve is closed, the doping agent is added into the doping material storage tank according to theoretical calculation amount, argon is introduced into the doping material storage tank for replacement, and after replacement is completed, a pressure stabilizing pipe fitting is opened, so that smooth feeding of the doping agent is guaranteed, and the device is simple to operate, safe and reliable. Independent feeding is realized, the dosage of the dopant can be accurately calculated according to actual production requirements, the resistivity of the drawn crystal bar is ensured, and the crystal pulling qualification rate is ensured.

Description

Crystal pulling furnace doping device

Technical Field

The utility model belongs to the technical field of polycrystalline silicon or monocrystalline silicon production, concretely relates to crystal pulling furnace doping device.

Background

At present, the heavily arsenic-doped silicon crystal bar has a wide market, but due to the physical characteristics of arsenic, the time for doping arsenic is in a state that a silicon material is melted, and due to evaporability, the arsenic in a silicon solution is evaporated in the crystal pulling process, so that the content is gradually reduced. After the crystal pulling fails and dissolves back, the doping needs to be supplemented to supplement the evaporated arsenic.

When a furnace platform of the existing arsenic-doped crystal pulling workshop is used for feeding a dopant, a doping tube doping mode is adopted, the arsenic dopant is stored by using a storage box during feeding, and the dopant is fed after melting. The arsenic stored in the first storage box is the doping amount calculated according to the resistivity specification of the crystal bar, the second storage box and the third storage box are fixed amounts, doping is carried out after crystal bar pulling fails and is re-dissolved, and the dopant cannot be added from the outside of the furnace body again in the crystal pulling process.

The first disadvantage of this doping method is that it can only ensure that the doping amount is accurate when the ingot is crystallized once, and if the ingot is drawn after being melted back, the doping amount is fixed, and the resistivity of the drawn ingot cannot be ensured. Secondly, the crystal pulling process can only ensure two to three times of complementary doping opportunities, once the dopant in the storage box is used up, the doping cannot be carried out, the resistivity of the pulled arsenic-doped crystal bar exceeds the standard, and the crystal bar is scrapped.

Disclosure of Invention

In view of this, the utility model provides a crystal pulling furnace doping apparatus that can add dopant to the crystal pulling furnace according to demand precision many times.

The utility model provides a technical scheme that its technical problem adopted is:

a crystal pulling furnace doping device comprises a doping pipe, an isolating valve and a doping material filling assembly, wherein one end of the doping pipe is fixedly connected with a crystal pulling furnace platform, the doping material filling assembly is connected with one end, far away from the crystal pulling furnace platform, of the doping pipe, and the isolating valve is arranged on the doping pipe and isolates the doping material filling assembly from the crystal pulling furnace platform; the doped material filling assembly comprises a doped material storage tank, an inert gas replacement pipe fitting and a pressure stabilizing pipe fitting, wherein the discharge end of the doped material storage tank is connected with the doped pipe and is positioned in front of the valve of the isolating valve, a doped material charging opening is formed in the upper end of the doped material storage tank, a sealing cover body is arranged on the doped material charging opening, and the inert gas replacement pipe fitting and the pressure stabilizing pipe fitting are respectively connected with the doped material storage tank.

Preferably, the inert gas replacement pipe fitting comprises an inert gas inlet pipe and an emptying pipe, the inert gas inlet pipe is communicated with the doping material storage tank and is provided with a replacement valve, and the emptying pipe is communicated with the doping material storage tank and is provided with an emptying valve.

Preferably, one end of the pressure stabilizing pipe fitting is communicated with the upper part of the doping material storage tank, the other end of the pressure stabilizing pipe fitting is communicated with the lower part of the doping material storage tank, and a pressure stabilizing valve is arranged on the pressure stabilizing pipe fitting.

Preferably, one end of the pressure stabilizing pipe fitting, which is far away from the lower part of the doping material storage tank, is communicated with the inert gas inlet pipe, and the pressure stabilizing valve and the replacement valve are arranged in parallel.

Preferably, one end of the emptying pipe, which is far away from the doping material storage tank, is connected with a vacuum generation pipe, a vacuum adjusting valve is arranged on the vacuum generation pipe, a vacuum meter is arranged on the doping material storage tank, and the vacuum meter is interlocked with the vacuum adjusting valve.

Preferably, an oxygen content analyzer is further arranged on the emptying pipe, and the oxygen content analyzer is interlocked with the replacement valve and the pressure stabilizing valve.

Preferably, the block valve is a solenoid valve or a pneumatic valve.

According to the technical scheme, the utility model provides a crystal pulling furnace doping device, its beneficial effect is: the doped material storage tank is separated from the crystal pulling furnace by the isolating valve through arranging the isolating valve and the doped material storage tank on the doped pipe. During doping operation, the isolating valve is closed, the doping agent is added into the doping material storage tank according to the theoretical calculation amount, the pipe fitting is replaced through the inert gas, argon is introduced into the doping material storage tank for replacement, and after replacement is completed, the pressure stabilizing pipe fitting is opened, so that smooth feeding of the doping agent is guaranteed, and the device is simple to operate, safe and reliable. The crystal pulling furnace doping device realizes independent feeding, can accurately calculate the dosage of the dopant according to actual production requirements, ensures the resistivity of a pulled crystal bar, can supplement the dopant into the crystal pulling furnace for multiple times, can accurately calculate the required dopant according to the residual quantity and the pulling time after crystal pulling failure and redissolution, accurately controls the resistivity of the crystal bar and ensures the crystal pulling qualification rate.

Drawings

FIG. 1 is a schematic view of the structure of a crystal pulling furnace doping apparatus.

In the figure: the device comprises a crystal pulling furnace doping device 10, a crystal pulling furnace platform 20, a doping pipe 100, an isolating valve 200, a doping material filling assembly 300, a sundry storage tank 310, a sealing cover body 311, an inert gas replacement pipe 320, an inert gas inlet pipe 321, a replacement valve 3211, an emptying pipe 322, an emptying valve 3221, a pressure stabilizing pipe 330, a pressure stabilizing valve 3301, a vacuum generation pipe 323 and a vacuum adjusting valve 3231.

Detailed Description

The following combines the drawings of the utility model to further elaborate the technical scheme and technical effect of the utility model.

Referring to FIG. 1, in one embodiment, a crystal puller doping apparatus 10 is used to add dopant to a crystal puller during production of heavily doped silicon rods. The crystal pulling furnace doping device 10 comprises a doping pipe 100, an isolating valve 200 and a doping material filling assembly 300, wherein one end of the doping pipe 100 is fixedly connected with the crystal pulling furnace platform 20, the doping material filling assembly 300 is connected with one end, far away from the crystal pulling furnace platform 20, of the doping pipe 100, and the isolating valve 200 is arranged on the doping pipe 100 and isolates the doping material filling assembly 300 from the crystal pulling furnace platform 20.

The dopant filling assembly 300 includes a dopant storage tank 310, an inert gas replacement pipe 320, and a pressure-stabilizing pipe 330, wherein a discharge end of the dopant storage tank 310 is connected to the dopant pipe 100 and is located in front of the valve of the isolating valve 200, a dopant charging port is disposed at an upper end of the dopant storage tank 310, the dopant charging port has a sealing cover 311 thereon, and the inert gas replacement pipe 320 and the pressure-stabilizing pipe 330 are respectively connected to the dopant storage tank 310.

When the heavily doped silicon rod is produced, the crystal pulling furnace doping device 10 is installed on the crystal pulling furnace and is communicated with the crystal pulling furnace through the doping pipe 100, and it is worth explaining that, in the present invention, the doping pipe 100 can be a commonly used doping pipe in the prior art, and the present invention is not limited in the present invention. When the dopant is required to be added into the crystal pulling furnace, the required dopant amount is calculated according to the actual material amount and the pulling time, the isolating valve 200 is closed, the sealing cover body 311 is opened, and the dopant is accurately added into the dopant storage tank 310. Closing the sealing cover body 311, opening the inert gas replacement pipe fitting 320, introducing argon gas into the doping material storage tank 310 for replacement until the content of the argon gas at the replacement gas outlet is more than 99.9%, closing the inert gas replacement pipe fitting 320, opening the pressure stabilizing pipe fitting 330, and ensuring that the doping agent can be discharged smoothly. When the time for adding the dopant is mature, the isolating valve 200 is opened, and the dopant in the dopant storage tank 310 is added into the crystal pulling furnace through the doping pipe 100, so that the dopant is added at one time. And after the addition is finished, closing the isolating valve, and repeating the operation to realize multiple times of dopant input. It should be noted that, in order to ensure the accuracy and timeliness of the dopant addition, the crystal pulling furnace doping apparatus 10 can be used alone or in parallel. In one preferred embodiment, the dopant filling assembly 300 includes at least two dopant storage tanks 310, and a plurality of dopant storage tanks 310 are disposed in parallel for switching use.

Further, the inert gas replacement pipe 320 includes an inert gas inlet pipe 321 and an emptying pipe 322, the inert gas inlet pipe 321 is connected to the doping material storage tank 310 and is provided with a replacement valve 3211, and the emptying pipe 322 is connected to the doping material storage tank 310 and is provided with an emptying valve 3221. One end of the pressure-stabilizing pipe 330 is communicated with the upper part of the doped material storage tank 310, and the other end is communicated with the lower part of the doped material storage tank 310, and a pressure-stabilizing valve 3301 is arranged on the pressure-stabilizing pipe 330. Preferably, one end of the pressure-stabilizing pipe 330, which is far away from the lower part of the dopant material storage tank 310, is communicated with the inert gas inlet pipe 321, and the pressure-stabilizing valve 3301 is arranged in parallel with the replacement valve 3211.

To prevent air from entering the crystal pulling furnace and affecting the crystal pulling quality, argon replacement of the dopant storage tank 310 and its accompanying plumbing is required after the dopant is added to the dopant storage tank 310. At this time, the replacement valve 3211 and the emptying valve 3221 are opened, argon is introduced into the doped material storage tank 310 for replacement, after a certain period of time, the argon content at the outlet of the emptying pipe 322 is detected, after the argon content is qualified, the replacement valve 3211 and the emptying valve 3221 are closed, and the pressure stabilizing valve 3301 is opened. It should be noted that, after the doping agent feeding is finished, a part of the doping agent may remain on the walls of the doping agent storage tank 310, which affects the doping agent feeding precision, so that, after the feeding is finished, the replacement valve 3211 may be opened, and argon may be introduced into the doping agent storage tank 310 for purging, so as to improve the doping agent feeding precision.

In a preferred embodiment, in order to reduce the influence on the atmosphere in the crystal pulling furnace during the dopant adding process, a vacuum generating pipe 323 is connected to one end of the emptying pipe 322, which is far away from the dopant storage tank 310, a vacuum regulating valve 3231 is arranged on the vacuum generating pipe 323, a vacuum gauge is arranged on the dopant storage tank 310, and the vacuum gauge is interlocked with the vacuum regulating valve 3231. After the doping agent is added into the doping material storage tank 310, the valve 3211 and the emptying valve 3221 are opened, the vacuum regulating valve is opened, argon gas replacement is performed on the crystal furnace doping device 10 system, and finally the pressure of the crystal furnace doping device 10 system and the pressure in the crystal pulling furnace are kept balanced.

Further, in order to realize the automatic and accurate control of the dopant feeding, an oxygen content analyzer is further arranged on the emptying pipe 322, and the oxygen content analyzer is interlocked with the replacement valve 3211 and the pressure stabilizing valve 3301. The block valve 200 is a solenoid valve or a pneumatic valve.

It should be noted that, in the above process, the related interlocks belong to the common technical knowledge of technicians in the automatic control category, and do not relate to technical improvement, and the present invention is not described in detail.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims (7)

1. A crystal pulling furnace doping device is characterized by comprising a doping pipe, an isolating valve and a doping material filling assembly, wherein one end of the doping pipe is fixedly connected with a crystal pulling furnace platform, the doping material filling assembly is connected with one end, far away from the crystal pulling furnace platform, of the doping pipe, and the isolating valve is arranged on the doping pipe and isolates the doping material filling assembly from the crystal pulling furnace platform;

the doped material filling assembly comprises a doped material storage tank, an inert gas replacement pipe fitting and a pressure stabilizing pipe fitting, wherein the discharge end of the doped material storage tank is connected with the doped pipe and is positioned in front of the valve of the isolating valve, a doped material charging opening is formed in the upper end of the doped material storage tank, a sealing cover body is arranged on the doped material charging opening, and the inert gas replacement pipe fitting and the pressure stabilizing pipe fitting are respectively connected with the doped material storage tank.

2. A crystal puller doping apparatus as set forth in claim 1 wherein said inert gas displacement tube includes an inert gas inlet tube and a vent tube, said inert gas inlet tube communicating with said dopant storage tank and being provided with a displacement valve, said vent tube communicating with said dopant storage tank and being provided with a vent valve.

3. A crystal puller doping apparatus as set forth in claim 2 wherein one end of the pressure stabilizing tube communicates with an upper portion of the dopant storage tank and the other end communicates with a lower portion of the dopant storage tank, and the pressure stabilizing tube is provided with a pressure stabilizing valve.

4. A crystal puller doping apparatus as set forth in claim 3 wherein an end of said pressure stabilizing tube remote from the lower portion of said dopant storage tank communicates with said inert gas inlet tube and said pressure stabilizing valve is disposed in parallel with said replacement valve.

5. A crystal pulling furnace doping apparatus as claimed in any one of claims 3 to 4, wherein an end of the evacuation tube remote from the dopant storage tank is connected to a vacuum generation tube, the vacuum generation tube is provided with a vacuum regulating valve, the dopant storage tank is provided with a vacuum gauge, and the vacuum gauge is interlocked with the vacuum regulating valve.

6. A crystal puller doping apparatus as set forth in claim 5 wherein an oxygen analyzer is also provided on the vent tube, the oxygen analyzer being interlocked with the replacement valve and the pressure maintaining valve.

7. A crystal puller doping apparatus as set forth in claim 1 wherein the block valve is a solenoid or pneumatic valve.

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