Technological method of finished-section silicon single crystal rod

Abstract

The invention relates to the technical field of monocrystalline silicon rod manufacturing, particularly provides a process method of a finished section monocrystalline silicon rod, and aims to solve the problems of more broken lines at the finished section and lower crystal pulling and forming rate of crystal pulling in a crystal pulling process after single crystal furnace equipment is upgraded. In order to achieve the purpose, the technological method of the silicon single crystal rod at the finishing section comprises the steps of seeding, necking down, shouldering, rotating shoulders and carrying out equal-diameter growth until crystal pulling is finished; wherein when the equal-diameter length of the single crystal silicon rod at the finishing section reaches 2000-2500mm, the power of the main heater is started to be increased, so that temperature compensation is carried out; and when the residual material in the crucible is reduced to 30%-35% of the feeding amount, the bottom heater is started so as to cooperate with the main heater for temperature compensation. Compared with the prior art, the temperature compensation is started in advance, and the bottom heater is started to cooperate with the main heater to compensate the temperature when the residual material in the crucible is reduced to 30-35% of the feeding amount, so that the temperature compensation requirement can be conveniently met, the line breaking condition of the finishing section is reduced, and the crystal pulling and forming rate is improved.

Description

Technical Field

[0001] The invention relates to the technical field of single crystal silicon rod manufacturing, and specifically provides a process method for a finished section of single crystal silicon rod. Background Art

[0002] At present, the production of single crystal silicon usually adopts the re-feeding direct pulling process, and its brief process includes: charging and melting, first loading solid silicon material into the quartz crucible, sealing the furnace body, introducing argon gas and making the entire single crystal furnace in a vacuum state, and pumping the gas and volatiles in the single crystal furnace to the outside of the single crystal furnace through a dry pump, and the main heater and the bottom heater heat the solid silicon material block to about 1420℃ to melt into silicon liquid; crystal seeding; diameter reduction; shoulder release; shoulder rotation; equal diameter; finishing and other process steps are cyclically operated; the last cycle of crystal pulling process becomes the completion section, and the previous cycle of crystal pulling process becomes the cycle section. Among them, only the main heater is used for heating during crystal seeding, diameter reduction, shoulder release, shoulder rotation, equal diameter, and finishing. As the running time increases, the single crystal furnace pipeline will be vented poorly, and the crucible will run for too long. The crucible will be reported as finished at around 400-450 hours according to the actual crystal pulling situation in the workshop. In the finishing stage, as the remaining material in the crucible decreases in the later stage, the overall temperature in the crucible drops rapidly, requiring timely heating and frequent attention. During the equal diameter growth process in the finishing stage, the power of the main heater is increased to compensate for the temperature to ensure the normal operation of the crystal pulling.

[0003] However, with the continuous updating of single crystal furnace equipment, the inventors of the present invention found that the original temperature compensation process could no longer meet the temperature compensation requirements of the finishing section, and it was difficult to effectively meet the temperature compensation requirements after adjusting the temperature compensation power for many times. The single crystal was severely deformed and twisted, the crystal pulling rate was low, and there were many wire breaks in the finishing section, which seriously affected the production efficiency and output of the workshop.

[0004] Therefore, this field needs a new technical solution to solve the above problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, namely, to solve the problem of frequent wire breakages in the completion section of the crystal pulling process and low crystal pulling rate after the single crystal furnace equipment is updated.

[0006] The present invention provides a process method for a single crystal silicon rod in a finishing section, the process method comprising seeding, necking, shoulder release, shoulder rotation, and equal-diameter growth until the crystal pulling is completed; wherein, when the equal-diameter length of the single crystal silicon rod in the finishing section reaches 2000 mm to 2500 mm, the power of the main heater begins to be increased for temperature compensation; when the remaining material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on to cooperate with the main heater for temperature compensation.

[0007] In the preferred technical solution of the above process method, the step of "when the remaining material in the crucible is reduced to 30% to 35% of the feeding amount, turning on the bottom heater to cooperate with the main heater for temperature compensation" specifically includes: when the remaining material in the crucible is reduced to 30% to 35% of the feeding amount, turning on the bottom heater and heating the bottom heater at a power of 0.5kw to 1.5kw to cooperate with the main heater for temperature compensation.

[0008] In the preferred technical solution of the above process method, the step of "heating the bottom heater at a power of 0.5-1.5kw" specifically includes: gradually increasing the heating power of the bottom heater to 0.5kw to 1.5kw.

[0009] In the preferred technical solution of the above process method, the liquid-to-mouth distance in the process of "equal-diameter growth until the end of crystal pulling" is greater than the liquid-to-mouth distance in the equal-diameter growth process of the circulation section.

[0010] In the preferred technical solution of the above process method, the liquid-to-mouth distance in the process of "equal-diameter growth until the end of crystal pulling" is 3 mm to 5 mm larger than the liquid-to-mouth distance in the equal-diameter growth process of the circulation section.

[0011] In the preferred technical scheme of the above-mentioned process method, the step of "when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, start to increase the power of the main heater for temperature compensation" specifically includes: when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, start to gradually increase the power of the main heater; when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 4000mm to 5000mm, the increase in the power of the main heater reaches a preset maximum value and remains unchanged during the subsequent growth process; wherein, the preset maximum value is 4kw to 7kw.

[0012] In the preferred technical solution of the above process method, when the equal diameter length of the single crystal silicon rod in the finishing section reaches 1500mm to 1700mm, the argon flow rate begins to increase; when the equal diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the furnace pressure begins to increase.

[0013] In the preferred technical scheme of the above-mentioned process method, the step of "starting to increase the argon gas flow rate when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm" specifically includes: before the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm, the argon gas flow rate is 100slpm; when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm, the argon gas flow rate is increased from 100slpm to 110slpm and remains unchanged during the subsequent equal diameter growth process; "when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm The step of "starting to increase the furnace pressure when the equal diameter length of the single crystal silicon rods in the finished section reaches 2000mm to 2500mm" includes: before the equal diameter length of the single crystal silicon rods in the finished section reaches 2000mm to 2500mm, the furnace pressure is 7 Torr; when the equal diameter length of the single crystal silicon rods in the finished section reaches 2000mm to 2500mm, the furnace pressure begins to gradually increase from 7 Torr; when the equal diameter length of the single crystal silicon rods in the finished section reaches 3000mm to 3500mm, the furnace pressure is increased to 10 Torr and remains unchanged during the subsequent equal diameter growth process.

[0014] In the preferred technical scheme of the above-mentioned process method, during the equal-diameter growth process, the pulling speed and the crucible speed both increase continuously when the equal-diameter length increases from 0 mm to 600 mm, remain unchanged when the equal-diameter length increases from 600 mm to 3000 mm, the pulling speed decreases when the equal-diameter length increases from 3000 mm to 6000 mm, and the crucible speed decreases when the equal-diameter length increases from 3000 mm to 3500 mm and remains unchanged in the subsequent process.

[0015] In the preferred technical solution of the above process method, the seeding power and the iso-crystal power of the finishing stage are respectively 0.8W to 1.2W smaller than the seeding power and the iso-crystal power of the circulation stage.

[0016] When the above technical solution is adopted, the process method of the single crystal silicon rod in the finishing section includes seeding, necking, shoulder release, shoulder rotation, and equal-diameter growth until the crystal pulling is completed; wherein, when the equal-diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the power of the main heater is increased to compensate for the temperature; when the remaining material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on to cooperate with the main heater for temperature compensation.

[0017] It should be noted that 2000 mm to 2500 mm refers to a numerical range including the two endpoints of 2000 mm and 2500 mm, and other expressions of the same manner in the present invention are all numerical ranges including the two endpoints.

[0018] After careful analysis and experimental verification, the inventor of the present invention found that the main reason for the frequent disconnection of the end section of the crystal pulling process and the low crystal pulling rate after the single crystal furnace equipment was replaced was that the vertical size of the main heater of the single crystal furnace was getting smaller and smaller. In recent years, with the improvement of single crystal furnace technology, in order to better control the content of oxygen and carbon and stabilize the solid-liquid interface to improve the quality of crystal pulling, the vertical size of the main heater of the single crystal furnace has become smaller and smaller. Although this can improve the quality of crystal pulling and reduce energy consumption, there are many disconnections in the end section of the crystal pulling process and the crystal pulling rate is low. The inventor of the present invention breaks through the conventional thinking in this field. When the equal diameter length of the single crystal silicon rod in the end section reaches 2000mm to 2500mm, the power of the main heater is increased to compensate for the temperature. Compared with the original process, the temperature compensation is started earlier, and when the residual material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on to cooperate with the main heater for temperature compensation, which can easily meet the temperature compensation requirements, reduce the disconnection of the end section, and improve the crystal pulling rate. In addition, the process method of the single crystal silicon rod in the finishing section of the present invention grows at a constant diameter until the crystal pulling is completed, and no finishing is performed, so that the constant diameter length of the pulled single crystal silicon rod is longer, thereby improving the yield.

[0019] Preferably, the step of "when the remaining material in the crucible is reduced to 30% to 35% of the amount of material fed, turning on the bottom heater to cooperate with the main heater for temperature compensation" specifically includes: when the remaining material in the crucible is reduced to 30% to 35% of the amount of material fed, turning on the bottom heater and heating it at a power of 0.5kw to 1.5kw to cooperate with the main heater for temperature compensation.

[0020] Through such a setting, the temperature compensation requirements can be met more effectively, the wire breakage in the finishing section can be reduced, and the crystal pulling rate can be improved.

[0021] Preferably, the liquid-to-mouth distance in the process of "constant-diameter growth until the end of crystal pulling" is greater than the liquid-to-mouth distance in the constant-diameter growth process of the circulation section.

[0022] Through such an arrangement, impurities evaporated from the solution in the crucible can be discharged from the single crystal furnace more quickly along with the argon gas, thereby reducing the influence of the impurities on the quality of the single crystal silicon rod.

[0023] Preferably, the step of "when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, start to increase the power of the main heater for temperature compensation" specifically includes: when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, start to gradually increase the power of the main heater; when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 4000mm to 5000mm, the increase in the power of the main heater reaches a preset maximum value and remains unchanged during the subsequent growth process; wherein, the preset maximum value of the power of the main heater is 4kw to 7kw.

[0024] Through such a setting, the heat loss caused by the increase in the liquid nozzle distance can be compensated, so that the temperature gradient in the single crystal furnace is maintained at a better state, reducing the risk of wire breakage in the finishing section, so as to ensure the quality of crystal pulling.

[0025] Preferably, when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm, the argon flow rate begins to increase; when the equal diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, the furnace pressure begins to increase.

[0026] Through such an arrangement, it is possible to further promote the impurities evaporated from the solution in the crucible to be discharged from the single crystal furnace along with the argon gas, thereby reducing the influence of the impurities on the quality of the single crystal silicon rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0028] Figure 1 It is a schematic diagram of the main steps of the process method for producing a single crystal silicon rod in the finishing stage of the present invention. DETAILED DESCRIPTION

[0029] First, it should be understood by those skilled in the art that the embodiments described below are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the invention, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] Based on the problem mentioned in the background technology that after the single crystal furnace equipment is upgraded, the completion stage of the crystal pulling process has many broken wires and the crystal pulling rate is low, the present invention provides a process method for the completion stage of the single crystal silicon rod. Figure 1 As shown, the process method of the single crystal silicon rod of the finishing stage of the present invention includes:

[0031] Step S100, seeding;

[0032] Step S200, necking;

[0033] Step S300, release the shoulders;

[0034] Step S400, rotating shoulders;

[0035] Step S500, equal diameter growth, when the equal diameter length reaches 2000 mm to 2500 mm, the power of the main heater begins to increase, and when the remaining material in the crucible is reduced to 30% to 35% of the feeding amount, the bottom heater is turned on;

[0036] Finish.

[0037] Compared with the original process method of the finishing section, the process method of the single crystal silicon rod of the finishing section of the present invention advances the temperature compensation node to the equal-diameter length of 2000mm to 2500mm during the equal-diameter growth process (the temperature compensation node of the single crystal silicon rod of the original process method of the finishing section during the equal-diameter growth process is at the equal-diameter length of 3000mm), and during the equal-diameter growth process of the finishing section, when the remaining material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on so that the bottom heater is used in cooperation with the main heater for temperature compensation (the original process method of the single crystal silicon rod of the finishing section only uses the main heater for temperature compensation during the equal-diameter growth process). When the remaining material in the crucible is reduced to 30% to 35% of the feed amount or less, the remaining material in the crucible is at the bottom of the crucible, especially when the liquid level of the remaining material melt in the crucible is below the R angle of the crucible, the main heater is relatively weak in the ability to compensate for the temperature, and it is relatively difficult to maintain a stable temperature. By advancing the compensation node, the trend of rapid temperature drop can be weakened, and during the equal-diameter growth process of the finishing section, when the remaining material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on, and the bottom heater is used to compensate for the temperature in coordination with the main heater to increase the temperature of the bottom of the crucible in a targeted manner, which can more effectively meet the compensation requirements, reduce temperature fluctuations, reduce the breakage of the finishing section, and improve the crystallization rate of the crystal pulling. In addition, the process method of the single crystal silicon rod in the finishing section of the present invention is equal-diameter growth until the end of crystal pulling, and no tailing is performed, so that the equal-diameter length of the pulled single crystal silicon rod is longer, and the yield is improved.

[0038] The step of "turning on the bottom heater when the remaining material in the crucible is reduced to 30% to 35% of the charged amount" specifically includes: when the remaining material in the crucible is reduced to 30% to 35% of the charged amount, turning on the bottom heater and heating the bottom heater at a power of 0.5kw to 1.5kw, so as to cooperate with the main heater for temperature compensation.

[0039] Through such a setting, the temperature compensation requirements can be met more effectively, the wire breakage in the finishing section can be reduced, and the crystal pulling rate can be improved.

[0040] Preferably, the liquid-to-mouth distance in the equal-diameter growth process of the finishing section of the present invention is greater than the liquid-to-mouth distance in the equal-diameter growth process of the circulation section.

[0041] Through such an arrangement, impurities evaporated from the melt in the crucible can be discharged from the single crystal furnace more quickly along with the argon gas, thereby reducing the influence of the impurities on the quality of the single crystal silicon rod.

[0042] Preferably, the step of "starting to increase the power of the main heater when the equal-diameter length reaches 2000mm to 2500mm" specifically includes: when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, starting to gradually increase the power of the main heater; when the equal-diameter length of the single crystal silicon rods in the finishing section reaches 4000mm to 5000mm, the increase in the power of the main heater reaches a preset maximum value and remains unchanged during the subsequent growth process; wherein, the preset maximum value of the power of the main heater is 4kw to 7kw.

[0043] As the distance between the liquid and the nozzle increases, the amount of heat lost increases, which will cause the temperature to drop. Through the above-mentioned setting, the heat loss caused by the increase in the distance between the liquid and the nozzle can be compensated, so that the temperature gradient in the single crystal furnace is maintained at a better state, and the risk of wire breakage in the finishing section is reduced, so as to ensure the quality of crystal pulling.

[0044] Preferably, when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500mm to 1700mm, the argon flow rate begins to increase; when the equal diameter length of the single crystal silicon rods in the finishing section reaches 2000mm to 2500mm, the furnace pressure begins to increase.

[0045] Through such an arrangement, it is possible to further promote the impurities evaporated from the melt in the crucible to be discharged from the single crystal furnace along with the argon gas, thereby reducing the influence of the impurities on the quality of the single crystal silicon rod.

[0046] The process of the single crystal silicon rod finishing stage of the present invention is described below in conjunction with the following comparative examples and embodiments.

[0047] Comparative Example

[0048] The process method of the single crystal silicon rod of the finishing stage includes:

[0049] Step DS100, seeding;

[0050] Step DS200, necking;

[0051] Step DS300, release shoulders;

[0052] Step DS400, shoulder rotation;

[0053] Step DS500, equal diameter growth;

[0054] Step DS600, ending.

[0055] Among them, the process parameters of step DS100, step DS200, step DS300, step DS400, and step DS600 are consistent with the parameters of the circulation section, and in step DS500, during the equal-diameter growth process, when the equal-diameter length is 3000mm, the power of the main heater is increased to compensate for the temperature.

[0056] The specific parameters of step DS500 are shown in Table 1: Table 1

[0057] It can be seen from Table 1 that when the equal diameter length of the single crystal silicon rod is 0mm, the growth setting pulling speed of the single crystal silicon rod is 72mm / hr, and when the equal diameter length of the single crystal silicon rod reaches 800mm, the growth setting pulling speed of the single crystal silicon rod reaches a peak value, and the peak value of the growth setting pulling speed of the single crystal silicon rod is 86mm / hr. In the process of the single crystal silicon rod from the equal diameter length of 800mm to 6000mm, the growth setting pulling speed of the single crystal silicon rod remains unchanged at 86mm / hr; during the equal diameter growth of the single crystal silicon rod, the rotation speed of the crucible is 4rpm to 6rpm, when the equal diameter length of the single crystal silicon rod is 0mm, the rotation speed of the crucible is 4rpm, and in the process of the single crystal silicon rod from the equal diameter length of 0mm to 600mm, the rotation speed of the crucible gradually increases from 4rpm to 6rpm, and in the process of the single crystal silicon rod from the equal diameter length The rotation speed of the crucible is maintained at 6rpm during the process of the equal diameter length of the single crystal silicon rod from 600mm to 6000mm; the liquid mouth distance is gradually reduced from 26mm to 18mm during the process of the equal diameter length of the single crystal silicon rod from 0mm to 800mm, and the liquid mouth distance is maintained at 18mm during the process of the equal diameter length of the single crystal silicon rod from 800mm to 6000mm; when the equal diameter length of the single crystal silicon rod reaches 3000mm, the power of the main heater begins to increase, and the power increase of the main heater increases with the increase of the equal diameter length. When the equal diameter length of the single crystal silicon rod reaches 6000mm, the power increase of the main heater reaches 5kw; during the entire equal diameter growth process of the single crystal silicon rod, the argon gas flow rate is maintained at 100slpm; during the entire equal diameter growth process of the single crystal silicon rod, the furnace pressure is maintained at 6torr.

[0058] According to the process method of the comparative example, the single crystal silicon rods of the finished section were pulled, and the broken wires accounted for about 20% of the single crystal silicon rods of the finished section.

[0059] Currently, the proportion of broken wires in the completed monocrystalline silicon rods in the industry is usually around 15%.

[0060] Example

[0061] The process method of the single crystal silicon rod of the finishing stage includes:

[0062] Step S110, seeding;

[0063] Step S210, necking;

[0064] Step S310, release shoulders;

[0065] Step S410: rotating shoulders;

[0100] Step S510, equal diameter growth;

[0101] Finish.

[0102] Among them, the seeding power in step S110 is 0.8kw to 1.2kw less than the seeding power in the circulation section, the isocrystal power in step S510 is 0.8kw to 1.2kw less than the isocrystal power in the circulation section, and the liquid inlet distance in step S510 is larger than the liquid inlet distance in the circulation section.

[0103] The specific parameters of step S510 are shown in Table 2: Table 2

[0104] It can be seen from Table 2 that when the equal diameter length of the single crystal silicon rod is 0mm, the growth setting pulling speed of the single crystal silicon rod is 72mm / hr, and when the equal diameter length of the single crystal silicon rod reaches 800mm, the growth setting pulling speed of the single crystal silicon rod reaches a peak value, and the peak value of the growth setting pulling speed of the single crystal silicon rod is 80mm / hr. In the process of the single crystal silicon rod from the equal diameter length of 800mm to 6000mm, the growth setting pulling speed of the single crystal silicon rod remains unchanged at 80mm / hr; during the equal diameter growth of the single crystal silicon rod, the rotation speed of the crucible is 4rpm to 6rpm, and the rotation speed of the crucible is 4rpm when the equal diameter length of the single crystal silicon rod is 0mm. In the process of the single crystal silicon rod from the equal diameter length of 0mm to 600mm, the rotation speed of the crucible is gradually increased from 4rpm to 6rpm. The crucible speed is gradually increased to 6rpm. When the single crystal silicon rod is from 600mm to 3000mm in equal diameter, the crucible speed is kept at 6rpm. When the single crystal silicon rod is from 3000mm to 3500mm in equal diameter, the crucible speed is gradually reduced from 6rpm to 5.5rpm. When the single crystal silicon rod is from 3500mm to 6000mm in equal diameter, the crucible speed is kept at 5.5rpm. When the single crystal silicon rod is from 0mm to 600mm in equal diameter, the liquid inlet distance is gradually reduced from 26mm to 22mm. When the single crystal silicon rod is from 600mm to 6000mm in equal diameter, the liquid inlet distance is kept at 22mm. When the single crystal silicon rod is from 2000mm to 6000mm in equal diameter, the crucible speed is gradually reduced from 6rpm to 5.5rpm. When the single crystal silicon rod is from 3000mm to 3500mm in equal diameter, the crucible speed is kept at 5.5rpm. When the equal diameter length of the single crystal silicon rod reaches 2500mm, the power of the main heater begins to increase, and the power increase of the main heater increases with the increase of the equal diameter length. When the equal diameter length of the single crystal silicon rod reaches 5000mm, the power increase of the main heater reaches 6kw, and the power of the main heater remains unchanged at 6kw during the process of the single crystal silicon rod from 600mm to 6000mm in length; when the equal diameter length of the single crystal silicon rod reaches 3500mm to 4500mm, the bottom heater is started to be turned on, and the heating power of the bottom heater increases with the increase of the equal diameter length of the single crystal silicon rod. When the equal diameter length of the single crystal silicon rod reaches 6000mm, the heating power of the bottom heater reaches 1.5kw; when the equal diameter length of the single crystal silicon rod is from 0mm to 1 During the process of the single crystal silicon rod increasing from 0mm to 2000mm, the furnace pressure remained unchanged at 7torr, the furnace pressure increased from 7torr to 10torr when the single crystal silicon rod was lengthened from 2000mm to 3500mm, and the furnace pressure remained unchanged at 10torr when the single crystal silicon rod was lengthened from 3500mm to 6000mm.

[0105] The single crystal silicon rods of the finished section were pulled using a single crystal furnace with a 34-inch, 37-inch, or 40-inch heat field according to the process method of the embodiment, and the broken wire ratio of the single crystal silicon rods of the finished section was 8% to 10%.

[0106] It can be seen that, according to the process method of the embodiment of the present invention, the broken wire ratio of the single crystal silicon rod in the finished section is much lower than the broken wire ratio of the single crystal silicon rod in the finished section drawn according to the original process method and the common broken wire ratio of the single crystal silicon rod in the finished section in the industry.

[0107] It should be noted that the bottom heater is turned on when the equal diameter length of the single crystal silicon rod reaches 3500mm to 4500mm. This is only a specific setting method, which can be adjusted in actual application, as long as the remaining material in the crucible is reduced to 30% to 35% of the feeding amount. In addition, when the equal diameter length of the single crystal silicon rod reaches 6000mm, the heating power of the bottom heater reaches 1.5kw. This is also a specific setting method, which can be adjusted in actual application. For example, the maximum heating power when the bottom heater cooperates with the main heater for temperature compensation is 0.5kw to 1.5kw. Of course, it can also be adaptively adjusted according to the collective thermal field.

[0108] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A process for finishing a single crystal silicon rod, characterized in that: The process method includes seeding, necking, shoulder release, shoulder rotation, and equal diameter growth until the crystal pulling is completed; Among them, when the equal diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the power of the main heater begins to be increased for temperature compensation; when the remaining material in the crucible is reduced to 30% to 35% of the feed amount, the bottom heater is turned on to cooperate with the main heater for temperature compensation.

2. The process according to claim 1, characterized in that: The step of "when the remaining material in the crucible is reduced to 30% to 35% of the amount of material charged, turning on the bottom heater to cooperate with the main heater for supplementary temperature" specifically includes: When the remaining material in the crucible is reduced to 30% to 35% of the feeding amount, the bottom heater is turned on and heated at a power of 0.5kw to 1.5kw to cooperate with the main heater for temperature compensation.

3. The process according to claim 2, characterized in that: The step of "heating the bottom heater at a power of 0.5 kW to 1.5 kW" specifically includes: The heating power of the bottom heater is gradually increased to 0.5 kw to 1.5 kw.

4. The process according to claim 1, characterized in that: The liquid-to-mouth distance in the process of "equal-diameter growth until the end of crystal pulling" is greater than the liquid-to-mouth distance in the equal-diameter growth process of the circulation section.

5. The process according to claim 4, characterized in that: The liquid inlet distance in the process of "constant diameter growth until the end of crystal pulling" is 3 mm to 5 mm larger than the liquid inlet distance in the constant diameter growth process of the circulation section.

6. The process according to claim 5, characterized in that: The step of "when the equal diameter length of the single crystal silicon rods in the finishing section reaches 2000 mm to 2500 mm, starting to increase the power of the main heater to compensate for the temperature" specifically includes: When the equal diameter length of the single crystal silicon rods in the finishing section reaches 2000 mm to 2500 mm, the power of the main heater begins to be gradually increased; When the equal diameter length of the single crystal silicon rod in the finishing section reaches 4000 mm to 5000 mm, the increase value of the power of the main heater reaches a preset maximum value and remains unchanged during the subsequent growth process; Among them, the preset maximum value is 4kw to 7kw.

7. The process according to any one of claims 1 to 6, characterized in that: When the equal diameter length of the single crystal silicon rod in the finishing section reaches 1500 mm to 1700 mm, the argon gas flow rate begins to increase; When the equal diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the furnace pressure begins to increase.

8. The process according to claim 7, characterized in that: The step of "starting to increase the argon gas flow rate when the equal diameter length of the single crystal silicon rods in the finishing section reaches 1500 mm to 1700 mm" specifically includes: When the equal diameter length of the single crystal silicon rod in the finishing section reaches 1500 mm to 1700 mm, the argon gas flow rate is 100 slpm; When the equal diameter length of the single crystal silicon rod in the finishing section reaches 1500 mm to 1700 mm, the argon gas flow rate is increased from 100 slpm to 110 slpm and remains unchanged during the subsequent equal diameter growth process; The step of "starting to increase the furnace pressure when the equal diameter length of the single crystal silicon rods in the finishing section reaches 2000 mm to 2500 mm" includes: When the equal diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the furnace pressure is 7torr; When the equal diameter length of the single crystal silicon rod in the finishing section reaches 2000mm to 2500mm, the furnace pressure begins to gradually increase from 7torr; When the equal-diameter length of the single crystal silicon rod in the finishing section reaches 3000mm to 3500mm, the furnace pressure is increased to 10torr and remains unchanged during the subsequent equal-diameter growth process.

9. The process according to claim 7, characterized in that: During the equal-diameter growth process, the pulling speed and the crucible speed increased continuously when the equal-diameter length increased from 0 mm to 600 mm, remained unchanged when the equal-diameter length increased from 600 mm to 3000 mm, the pulling speed decreased when the equal-diameter length increased from 3000 mm to 6000 mm, and the crucible speed decreased when the equal-diameter length increased from 3000 mm to 3500 mm and remained unchanged in the subsequent process.

10. The process according to claim 7, characterized in that: The seeding power and iso-crystal power of the finishing stage are respectively 0.8W to 1.2W smaller than the seeding power and iso-crystal power of the circulation stage.

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