Evacuator for single crystal furnace and system for reducing oxygen content of single crystal

Abstract

The utility model discloses an evacuator for a single crystal furnace and a system for reducing the oxygen content of a single crystal. The evacuator for the single crystal furnace comprises a dust removal unit and a vacuum pump, wherein one end of the dust removal unit is connected with the middle upper part of the single crystal furnace, the other end of the dust removal unit is connected with the vacuum pump, and the vacuum pump is also connected with the bottom of the single crystal furnace. According to the evacuator for the single crystal furnace, secondary introduction of oxygen can be prevented, the content of oxygen is reduced, the quality of a crystal bar is improved, meanwhile, corrosion of volatile matters to a heater is reduced, and the service life of the heater is prolonged.

Description

Technical Field

[0001] The utility model relates to an evacuation device for a single crystal furnace and a system for reducing the oxygen content of a single crystal. Background Art

[0002] During the single crystal pulling process, the quartz crucible wall reacts with the molten silicon liquid: SiO2(s)→Si(l)+2O; the oxygen atoms generated by the quartz crucible wall are stirred by natural convection and evenly distributed in the silicon liquid; the oxygen atoms transmitted to the surface of the silicon solution by convection will evaporate in the form of SiO. (Si(l)+O→SiO(g); most of the volatilized SiO gas stays in the "area" as shown in the figure or even returns to the surface of the silicon liquid, causing oxygen to enter the silicon liquid for the second time, which will affect the quality of the oxygen content of the crystal rod (high oxygen will increase the proportion of concentric circles, affecting the minority carrier life of the single crystal and other unfavorable factors). N-type single crystals will have 100mm of the head length cut off due to the high oxygen content in the head of the single crystal, resulting in a waste of cost. On the other hand, according to the existing argon flow method, the argon gas introduced from the upper part will take away the volatiles generated in the furnace from the lower part of the furnace bottom. This path must pass through the heater (graphite material), which will react with the volatiles to form attachments attached to the heater. When cleaning the heater, it will be polished, resulting in a reduced service life of the heater. Utility Model Content

[0003] In view of this, one object of the utility model is to provide an evacuation device for a single crystal furnace, which can prevent the secondary introduction of oxygen, reduce the oxygen content, improve the quality of the crystal rod, and reduce the corrosion of the heater by volatiles, thereby extending the life of the heater. Another object is to provide a system for reducing the oxygen content of a single crystal.

[0004] The utility model adopts the following technical solutions to achieve the above purpose.

[0005] On the one hand, the utility model provides an evacuation device for a single crystal furnace, comprising a dust removal unit and a vacuum pump; wherein:

[0006] One end of the dust removal unit is connected to the middle and upper part of the single crystal furnace, and the other end is connected to the vacuum pump, and the vacuum pump is also connected to the bottom of the single crystal furnace.

[0007] In the utility model, the vacuum device for the single crystal furnace is mainly composed of a vacuum pump and a dust removal unit. One end of the dust removal unit is connected to the single crystal furnace, and the other end is connected to the vacuum pump, and the other end of the vacuum pump is connected to the bottom of the single crystal furnace. The vacuum pump is used to evacuate the "area" position in the furnace, and a part of the oxides produced by the reaction and volatilization of the silicon liquid and the quartz crucible are directly taken away from the pipeline connected to the upper insulation cylinder, preventing oxygen from staying in the internal "area" and returning to the silicon liquid, causing secondary introduction of oxygen. At the same time, this part of the oxides does not need to pass through the heater, which also reduces the corrosion of the heater by volatiles and extends the life of the heater.

[0008] According to the vacuuming device for a single crystal furnace described in the utility model, preferably, it also includes a pipeline; the pipeline includes a first pipeline, a second pipeline and a third pipeline; one end of the dust removal unit is connected to the middle and upper part of the single crystal furnace through the first pipeline, and the other end is connected to the vacuum pump through the second pipeline, and the vacuum pump is also connected to the bottom of the single crystal furnace through the third pipeline.

[0009] According to the evacuation device for a single crystal furnace of the utility model, preferably, a ball valve is provided in the first pipeline, so that the flow rate of the gas can be controlled.

[0010] According to the vacuuming device for a single crystal furnace described in the utility model, preferably, the dust removal unit includes a dust removal tank and a dust removal bag, the dust removal bag is hung on the dust removal tank, one end of the dust removal tank is connected to the first pipe, and the other end is connected to the second pipe.

[0011] In the utility model, a dust removal unit is provided, which is mainly used to remove part of the volatile matter to prevent the blockage of the subsequent pipeline. There are no special requirements for the dust removal unit, and those dust removal devices already available in the art can be used. According to a specific embodiment of the utility model, the dust removal unit is provided as a dust removal tank, on which a dust removal bag is provided.

[0012] According to the vacuum pump for a single crystal furnace described in the utility model, preferably, the third pipeline includes a main pipeline, a first branch pipeline, a second branch pipeline and an outlet, the main pipeline is connected to the vacuum pump, the first branch pipeline and the second branch pipeline are respectively arranged perpendicular to the main pipeline, and are respectively connected to the bottom of the single crystal furnace; the outlet is arranged on the main pipeline.

[0013] According to the evacuation device for a single crystal furnace described in the utility model, preferably, the main pipeline is arranged horizontally; the first branch pipeline and the second branch pipeline are arranged at intervals and are located on the same side of the main pipeline; and the outlet is arranged on the other side of the main pipeline.

[0014] On the other hand, the utility model also provides a system for reducing the oxygen content of a single crystal, comprising a single crystal furnace and the evacuation device for the single crystal furnace as described above.

[0015] According to the system for reducing the oxygen content of a single crystal of the utility model, preferably, the single crystal furnace comprises a guide tube, an upper insulation tube, an insulation felt, a heater and a crucible; wherein,

[0016] The guide tube and the upper heat-insulating tube are both located above the crucible; the heater is arranged near the upper part of the crucible; and the heat-insulating felt is arranged outside the upper heat-insulating tube.

[0017] According to the system for reducing the oxygen content of a single crystal of the utility model, preferably, a first exhaust pipe and a second exhaust pipe are provided at the bottom of the single crystal furnace; the first exhaust pipe and the second exhaust pipe are vertically and spaced apart.

[0018] According to the system for reducing the oxygen content of a single crystal of the utility model, preferably, the first exhaust pipe is connected to the first branch pipe; and the second exhaust pipe is connected to the second branch pipe.

[0019] The system of the utility model mainly operates in two paths: one is to discharge the volatiles carried by the argon gas to the main pipeline through the external vacuum device, and the other is to discharge the volatiles carried by the argon gas to the first branch pipeline and the second branch pipeline through the first exhaust pipe and the second exhaust pipe according to the existing path, and then the exhaust pipes are combined and discharged through the outlet. This not only reduces the oxygen content as a whole, but also reduces the corrosion of the heater.

[0020] Compared with the prior art, the vacuum device for single crystal furnace of the utility model has the following beneficial effects:

[0021] (1) Use a vacuum pump to evacuate the "zone" in the furnace, and take away the oxides produced by the reaction of silicon liquid and quartz crucible directly from the upper insulation tube vacuum pipe connected to the external vacuum system to prevent oxygen from staying in the internal "zone" and returning to the silicon liquid, causing secondary introduction of oxygen.

[0022] (2) It reduces the corrosion of volatile substances to the heater, which also plays a certain role in the life of the heater.

[0023] (3) Reduce the oxygen content, improve the quality of the crystal rod, improve the single crystal that is cut due to oxygen content, and increase the weight of the output finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the system for reducing the oxygen content of a single crystal according to the utility model.

[0025] Description of reference numerals:

[0026] 1-first pipeline, 11-ball valve;

[0027] 21-dust removal tank, 22-dust removal bag;

[0028] 3- Vacuum pump;

[0029] 4- Second pipeline;

[0030] 5-third pipeline, 51-main pipeline, 52-first branch pipeline, 53-second branch pipeline, 54-export;

[0031] 210 - flow guide tube, 220 - upper heat preservation tube, 230 - heat preservation felt, 240 - heater, 250 - crucible, 260 - first exhaust pipe, 261 - second exhaust pipe. DETAILED DESCRIPTION

[0032] Hereinafter, preferred embodiments of the present utility model will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in this specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but are interpreted based on the meanings and concepts corresponding to the technical aspects of the present utility model, which are based on the principle of allowing the inventor to appropriately define the terms for the best explanation.

[0033] In addition, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present disclosure. Therefore, it should be understood that other equivalents and modifications may be made thereto without departing from the spirit and scope of the present invention when the present application was filed.

[0034] Example 1

[0035] Figure 1 It is a schematic diagram of the structure of the system for reducing the oxygen content of a single crystal according to the utility model.

[0036] like Figure 1 As shown, the vacuum device for a single crystal furnace of the utility model comprises a first pipeline 1, a dust removal unit, a vacuum pump 3, a second pipeline 4 and a third pipeline 5. One end of the dust removal unit is connected to the first pipeline 1, and the other end is connected to the vacuum pump 3 through the second pipeline 4, and the vacuum pump 3 is also connected to the third pipeline 5. Among them, the end of the first pipeline 1 away from the dust removal unit is connected to the middle and upper part of the single crystal furnace, and the part of the third pipeline away from the vacuum pump 3 is connected to the bottom of the single crystal furnace.

[0037] The dust removal unit includes a dust removal tank 21 and a dust removal bag 22. The dust removal bag 22 is hung on the dust removal tank 21. The inlet end of the first pipe 1 is connected to the upper insulation cylinder 220 of the single crystal furnace, and the outlet end of the first pipe 1 is connected to the top of the dust removal tank 21. The bottom end of the dust removal tank 21 is connected to one end of the second pipe 4, and the other end of the second pipe 4 is connected to the vacuum pump 3. The vacuum pump 3 is also connected to the bottom of the single crystal furnace through the third pipe 5.

[0038] A ball valve 11 is provided in the first pipeline 1 to control the flow rate of the gas.

[0039] The third pipeline 5 includes a main pipeline 51, a first branch pipeline 52, a second branch pipeline 53 and an outlet 54. The main pipeline 51 is arranged horizontally and connected to the vacuum pump 3. The first branch pipeline 52 and the second branch pipeline 53 are respectively perpendicular to the main pipeline 51, and the two are arranged at intervals and located on the same side of the main pipeline 51. The outlet 54 is arranged on the other side of the main pipeline 51. The first branch pipeline 52 and the second branch pipeline 53 are respectively connected to the bottom of the single crystal furnace.

[0040] The following describes in detail the method for using the vacuum device for a single crystal furnace of this embodiment:

[0041] like Figure 1 As shown, argon gas is blown directly on the surface of silicon liquid through the guide tube 210, and the gas flows back into the internal area of ​​the upper insulation barrel 220 to form a concentrated reflux. A part of it passes through the first pipe 1 with a ball valve 11 on the outside. At the same time, with the help of the suction force of the vacuum pump 3, the volatile oxygen in the internal area of ​​the upper insulation barrel 220 is sucked into the first pipe 1, flows through the dust removal tank 21, and passes through the dust removal bag 22 to remove part of the volatiles to prevent blockage of the subsequent pipelines. When the furnace is stopped, the volatiles on it are cleaned. Finally, the volatiles carried by the argon gas enter the main pipeline 51 through the second pipeline 4 and the vacuum pump 3. Another part of the argon gas will be discharged to the first branch pipeline 52 and the second branch pipeline 53 through the first exhaust pipe 260 and the second exhaust pipe 261 according to the existing path. After the several are merged, they are discharged through the outlet 54.

[0042] Example 2

[0043] like Figure 1 As shown, this embodiment provides a system for reducing the oxygen content of a single crystal, including a single crystal furnace and an evacuation device as described in Example 1, wherein the single crystal furnace specifically includes: a guide tube 210, an upper insulation tube 220, an insulation felt 230, a heater 240, a crucible 250, a first exhaust pipe 260, and a second exhaust pipe 261.

[0044] The guide tube 210 and the upper heat-insulating tube 220 are both located above the crucible 250. The heater 240 is disposed near the upper portion of the crucible 250. The heat-insulating felt 230 is disposed outside the upper heat-insulating tube 220;

[0045] The bottom of the single crystal furnace is provided with a first exhaust pipe 260 and a second exhaust pipe 261. The first exhaust pipe 260 is connected to the first branch pipe 52. The second exhaust pipe 261 is connected to the second branch pipe 53.

[0046] In the prior art, argon is introduced from the upper part of the single crystal furnace, passes through the heater 240, and is discharged from the first exhaust pipe 260 and the second exhaust pipe 261 at the lower part of the furnace bottom to take away the volatiles generated in the furnace. The utility model adopts an external evacuation device, so that a part of the argon is directly taken away from the pipeline connected to the upper insulation cylinder 220 to prevent the secondary introduction of oxygen. At the same time, this part of the argon does not need to pass through the heater 240. Compared with the prior art, the corrosion of the heater 240 by volatiles is reduced, and the life of the heater 240 is increased.

[0047] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement, and substitution that can be thought of by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A vacuum device for a single crystal furnace, characterized in that: It includes a dust removal unit and a vacuum pump; wherein, One end of the dust removal unit is connected to the middle and upper part of the single crystal furnace, and the other end is connected to the vacuum pump, and the vacuum pump is also connected to the bottom of the single crystal furnace.

2. The evacuation device for a single crystal furnace according to claim 1, characterized in that: It also includes pipelines; the pipelines include a first pipeline, a second pipeline and a third pipeline; one end of the dust removal unit is connected to the upper and middle part of the single crystal furnace through the first pipeline, and the other end is connected to the vacuum pump through the second pipeline, and the vacuum pump is also connected to the bottom of the single crystal furnace through the third pipeline.

3. The evacuation device for a single crystal furnace according to claim 2, characterized in that: A ball valve is arranged in the first pipeline.

4. The evacuation device for a single crystal furnace according to claim 3, characterized in that: The dust removal unit comprises a dust removal tank and a dust removal bag, wherein the dust removal bag is hung on the dust removal tank, one end of the dust removal tank is connected to the first pipe, and the other end of the dust removal tank is connected to the second pipe.

5. The evacuation device for a single crystal furnace according to claim 4, characterized in that: The third pipeline includes a main pipeline, a first branch pipeline, a second branch pipeline and an outlet. The main pipeline is connected to the vacuum pump. The first branch pipeline and the second branch pipeline are respectively arranged perpendicular to the main pipeline and are respectively connected to the bottom of the single crystal furnace; the outlet is arranged on the main pipeline.

6. The evacuation device for a single crystal furnace according to claim 5, characterized in that: The main pipeline is arranged transversely; the first branch pipeline and the second branch pipeline are arranged at intervals and are located on the same side of the main pipeline; and the outlet is arranged on the other side of the main pipeline.

7. A system for reducing the oxygen content of a single crystal, characterized in that: It comprises a single crystal furnace and an evacuation device for the single crystal furnace as claimed in claim 6.

8. The system for reducing the oxygen content of a single crystal according to claim 7, characterized in that: The single crystal furnace comprises a guide tube, an upper insulation tube, insulation felt, a heater and a crucible; wherein, The guide tube and the upper heat-insulating tube are both located above the crucible; the heater is arranged near the upper part of the crucible; and the heat-insulating felt is arranged outside the upper heat-insulating tube.

9. The system for reducing the oxygen content of a single crystal according to claim 8, characterized in that: A first exhaust pipe and a second exhaust pipe are arranged at the bottom of the single crystal furnace; the first exhaust pipe and the second exhaust pipe are arranged vertically and at intervals.

10. The system for reducing oxygen content in a single crystal according to claim 9, characterized in that: The first exhaust pipe is connected to the first branch pipe; the second exhaust pipe is connected to the second branch pipe.

Images