Automatic feeding control method in monocrystalline silicon manufacturing

Abstract

The invention relates to the technical field of semiconductor manufacturing, in particular to an automatic feeding control method in monocrystalline silicon manufacturing, which comprises the following steps: S1, obtaining the weight of residual materials in a furnace; s2, determining the weight of materials which should be fed in the furnace, and rechecking the weight of the materials which should be fed in the furnace; s3, the corresponding actual minority carrier lifetime of the crystal bar in the Rn time period is obtained, and the cycle material proportion of the crystal bar in the Rn + 2 time period is adjusted; and S4, preparing materials in the material room according to the weight of the materials to be fed in the furnace and the proportion of the circulating materials. The requirement for manually calculating the feeding amount is reduced, labor hour waste and production delay caused by manual calculation errors are reduced, therefore, the reliability and accuracy of the production process are improved, the opportunity that personnel participate in dangerous operation is reduced, the possibility of safety accidents is reduced, meanwhile, the service life of the minority carrier of the crystal bar is monitored in real time, and the service life of the crystal bar is prolonged. And the proportion of the circulating material is dynamically adjusted, so that the quality consistency of the crystal bar in different growth stages is ensured, and the quality and the performance of a final product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to an automatic feeding control method in single crystal silicon manufacturing. Background Art

[0002] Monocrystalline silicon is one of the indispensable basic materials in the semiconductor industry and is widely used in integrated circuits, solar cells and other fields. The manufacture of monocrystalline silicon usually adopts technologies such as the CZ method or the zone melting method. Among them, the CZ method has become one of the mainstream monocrystalline silicon production methods due to its large feed volume, large single crystal diameter, and high degree of equipment automation.

[0003] The Czochralski method is a single crystal silicon production process optimized by a continuous feeding system. Its core lies in the use of a continuous feeding system to achieve efficient and continuous single crystal silicon rod pulling. The process first melts the polysilicon raw material by heating, and then uses the seed crystal to guide and continuously pull single crystal silicon under stable growth conditions. In this process, by precisely controlling the temperature gradient and pulling speed, the silicon atoms in the melt are rearranged and grown on the seed crystal to form high-quality single crystal silicon rods.

[0004] Compared with the traditional Czochralski method, the optimized Czochralski method (such as the RCZ method) uses a feeding device to add new silicon material into the crucible after the first pulling is completed, and repeats the above melting and growth process to pull the next crystal rod, thereby reducing the loading and melting time, improving production efficiency, and reducing production costs.

[0005] During the operation of a single crystal silicon furnace, when the crystal rod is broken or the end of the crystal rod is reached, the on-site personnel need to manually calculate the amount of remaining material in the furnace, evaluate the weight of the added material, and manually report it to the material preparation room. At the same time, the material preparation room starts preparing materials based on the information reported by the on-site production personnel. The material preparation personnel will deliver the barrels filled with raw materials to the site, and then re-add materials on site. However, this traditional manual operation method has the following disadvantages:

[0006] The process of manual calculation and information reporting is cumbersome and affects production efficiency. At the same time, errors may occur during manual calculation, leading to safety accidents. Manual operation increases additional labor costs and it is difficult for manual operation to quickly respond to changes in production line requirements. Summary of the invention

[0007] The purpose of the present invention is to provide an automated feeding control method in the manufacture of single crystal silicon, so as to solve the problem raised in the above background technology that manual material reporting is time-consuming and error-prone, resulting in low production efficiency and high production costs, thereby realizing effective monitoring and management of the crystal pulling process and improving production efficiency and product quality.

[0008] The technical solution of the present invention is: an automatic feeding control method in single crystal silicon manufacturing, the automatic feeding control method comprising the following steps:

[0009] S1: Obtain the weight of the remaining material in the furnace according to the drawing progress of the crystal rod;

[0010] S2: Determine the weight of the material to be added to the furnace by the weight of the remaining material in the furnace, and review the weight of the material to be added to the furnace. If the weight of the material to be added to the furnace passes the review, the next step is executed. Otherwise, an alarm is manually processed;

[0011] S3: obtaining an actual minority carrier lifetime corresponding to the crystal rod in the Rn period, determining a difference between the actual minority carrier lifetime corresponding to the Rn period and a target minority carrier lifetime corresponding to the Rn period, and adjusting a recycling material ratio of the crystal rod in the Rn+2 period according to the difference;

[0012] S4: The material room prepares materials according to the weight of materials to be added to the furnace and the proportion of circulating materials.

[0013] Furthermore, in step S1, the weight of the remaining material in the furnace is obtained as follows:

[0014] S1.1: Determine the wire breakage after the crystal ingot is drawn according to the drawing progress of the crystal ingot;

[0015] S1.2: Obtain the weight of the remaining material in the furnace according to the wire breakage condition of the crystal rod after being pulled.

[0016] Furthermore, the wire breakage situations after the crystal rod is pulled include but are not limited to taking a section to finish and adding materials, adding materials when the wire is broken, stopping the pulling without adding materials at the end, and re-leading without adding materials when the wire is broken.

[0017] Furthermore, in step S2, the weight of the material to be added to the furnace is reviewed as follows:

[0018] S2.1: Determine the weight of material to be added to the furnace based on the weight of the remaining material in the furnace, specifically:

[0019] D=Aa-10kg

[0020] Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and a is the remaining material in the single crystal furnace;

[0021] S2.2: Set the product retention rate and review the weight of the material to be added to the furnace. The review formula is as follows:

[0022] ρ×A+15kg≥D

[0023] Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and ρ is the product pot retention rate;

[0024] When the review formula is satisfied, the weight of the material to be added to the furnace is reviewed and passed, and the next step is executed. Otherwise, an alarm is manually processed.

[0025] Furthermore, in step S3, the circulating material ratio of the crystal rod in the Rn+2 period is adjusted as follows:

[0026] S3.1: Obtain the actual minority carrier lifetime corresponding to the crystal rod in the Rn period by measuring method;

[0027] S3.2: Set the target minority carrier lifetime corresponding to the crystal rod in the Rn period;

[0028] S3.3: Obtain the difference between the actual minority carrier lifetime and the target minority carrier lifetime corresponding to the crystal rod in the Rn period, and compare the difference with the preset difference. When the difference is not less than the preset difference, the circulating material ratio is set to the first-level downward adjustment ratio; otherwise, the circulating material ratio is set to the second-level downward adjustment ratio.

[0029] Furthermore, the measurement method includes but is not limited to a microwave photoconductivity decay method, a quasi-steady-state photoconductivity method, a surface photovoltage method, a diffusion length method, a transient photoconductivity decay method, and a steady-state photoconductivity method.

[0030] Furthermore, the first-level downward adjustment ratio is smaller than the second-level downward adjustment ratio.

[0031] Furthermore, the recycling material ratio is divided according to the pulling period of the crystal rod, as follows:

[0032] The proportion of recycled materials corresponding to the R1 period, R2 period and R3 period is as follows:

[0033] When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 30%-35%, otherwise, the second-level downward adjustment ratio is set to 40%-50%;

[0034] The proportion of recycled materials corresponding to the R4 period, R5 period and R6 period is as follows:

[0035] When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 30%-35%, otherwise, the second-level downward adjustment ratio is set to 45%-50%;

[0036] The proportion of recycled materials corresponding to the remaining period is as follows:

[0037] When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 40%-50%, otherwise, the second-level downward adjustment ratio is set to 50%-55%.

[0038] Furthermore, during the R1 period and the R2 period in the crystal rod pulling process, the material room prepares materials according to the weight of materials to be added to the furnace.

[0039] The present invention provides an automated feeding control method in single crystal silicon manufacturing through improvement, which has the following improvements and advantages compared with the prior art:

[0040] Firstly, the present invention reduces the need for manual calculation of the amount of material added through an automated control method, reduces the waste of man-hours and production delays caused by human calculation errors, thereby improving the reliability and accuracy of the production process, while also reducing the chances of personnel participating in dangerous operations and reducing the possibility of safety accidents;

[0041] Second, the present invention monitors the minority carrier lifetime of the crystal rod in real time and adjusts the feeding ratio according to the difference between the actual value and the target value of the minority carrier lifetime, thereby optimizing the use of recycled materials in the production process and improving the material utilization rate. At the same time, by monitoring and adjusting the minority carrier lifetime, the quality consistency of the crystal rod at different growth stages is ensured, thereby improving the quality and performance of the final product.

[0042] Thirdly, the present invention can dynamically adjust the proportion of circulating materials at different stages of crystal rod pulling, making the production process more flexible and able to respond to changes in production conditions in a timely manner, thereby ensuring the stability and continuity of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be further explained below in conjunction with the accompanying drawings and embodiments:

[0044] Figure 1 It is a schematic flow chart of the automatic feeding control method of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that, in the description of the present invention, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0047] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0048] It should be noted that like reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not require further detailed discussion and description in the description of the subsequent drawings.

[0049] refer to Figure 1 This embodiment provides an automatic feeding control method in single crystal silicon manufacturing, and the automatic feeding control method specifically includes the following steps:

[0050] Step S1: According to the pulling progress of the crystal rod, the weight of the remaining material in the furnace is obtained. The details are as follows:

[0051] Step S1.1: Determine the wire breakage after the ingot is pulled according to the ingot pulling progress. The wire breakage after the ingot is pulled includes but is not limited to adding material at the end of the segment, adding material after the wire is broken, stopping the pull without adding material at the end, and re-releasing without adding material after the wire is broken. That is, after the ingot is pulled, determine which of the above wire breakage conditions the wire breakage after the ingot is pulled belongs to.

[0052] Specifically, when it is the end of the segmentation and the end of the line feeding and the end of the line feeding, the next step needs to be executed to obtain the weight of the remaining material in the furnace. When it is the end of the line without feeding and the pulling is stopped, the pulling of the crystal rod can be directly ended, that is, the whole process stops. When it is the end of the line without feeding and re-leading, the crystal rod can be directly pulled without feeding, that is, the next step is not executed to obtain the weight of the remaining material in the furnace.

[0053] Step S1.2: Obtain the weight of the remaining material in the furnace according to the wire breakage after the crystal rod is pulled. Specifically, the amount of remaining material in the current single crystal furnace can be automatically obtained by weighing in the furnace, where weighing in the furnace includes but is not limited to weighing methods such as sensors and manual measurement. The amount of remaining material in the current single crystal furnace can also be obtained by setting a weighing device at the bottom of the furnace.

[0054] Step S2: Determine the weight of the remaining material in the furnace obtained in step S1.2, and verify the weight of the material to be added to the furnace by the product retention rate. If the weight of the material to be added to the furnace is verified, the next step will be executed. Otherwise, the alarm will be manually processed. The details are as follows:

[0055] Step S2.1: The actual amount to be added in the single crystal furnace is obtained by using the weight of the remaining material in the furnace obtained in step S1.2 and the weight of the full pot in the single crystal furnace, specifically:

[0056] D=Aa-10kg

[0057] Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and a is the remaining material in the single crystal furnace.

[0058] Furthermore, the full pot weight A in the single crystal furnace in this embodiment is an estimated weight, which is specifically estimated according to the crucible size. For example, a crucible with a height of 630 mm has a corresponding maximum charge weight of 860 kg, a crucible with a height of 680 mm has a corresponding maximum charge weight of 950 kg, and a crucible with a height of 750 mm has a corresponding maximum charge weight of 1020 kg.

[0059] Step S2.2: According to the actual needs of the drawing process, the value of the product pot retention rate is specifically set. That is, there is no clear limit on the size of the product pot retention rate, which can be selected according to the actual use needs.

[0060] Specifically, the weight of the material to be added to the furnace is reviewed by setting the product retention rate. In this embodiment, the review formula is specifically:

[0061] ρ×A+15kg≥D

[0062] Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and ρ is the product pot retention rate.

[0063] That is to say, when the actual amount D to be added in the single crystal furnace obtained in step S2.1 and the set product pot retention rate ρ meet the above-mentioned verification formula, it means that the actual amount D to be added in the single crystal furnace obtained in step S2.1 has passed the review, that is, the actual amount D to be added in the single crystal furnace obtained in step S2.1 is the actual amount to be added required in the subsequent step, and the next step S3 is executed at the same time. On the contrary, that is, when the actual amount D to be added in the single crystal furnace obtained in step S2.1 and the set product pot retention rate ρ do not meet the above-mentioned verification formula, it means that the actual amount D to be added in the single crystal furnace obtained in step S2.1 is too much, and an alarm is required at this time, and the actual amount D to be added in the single crystal furnace obtained in step S2.1 is reduced by manual operation.

[0064] Step S3: During the actual drawing process of the crystal rod, it can be divided into multiple time periods, and each time period will produce a certain number of crystal rods. It is worth noting that after the crystal rod is pulled, the crystal rod is usually reprocessed, such as cutting, grinding, etc. During this reprocessing process, the crystal rod will experience a certain degree of loss, which includes physical wear of the crystal rod itself and debris and scraps generated during the processing. The residual materials generated during these losses, those that meet the quality standards, can be collected as recycled materials and put back into the single crystal furnace for subsequent crystal rod pulling, thereby realizing the reuse of resources.

[0065] Specifically, the addition of recycled material will have a direct impact on the weight of the remaining material in the single crystal furnace. This is because each addition of recycled material will change the total amount of remaining silicon material in the furnace. This change not only affects the calculation of the subsequent feeding amount, but also affects the quality of the new crystal rod. In order to ensure the stability of the quality of the crystal rod, it is necessary to dynamically adjust the weight of the remaining material in the furnace and the subsequent feeding strategy according to the amount of recycled material added. Therefore, after obtaining the weight of the remaining material in the single crystal furnace, it is necessary to adjust the corresponding recycled material ratio so as to adjust the feeding plan in time. The details are as follows:

[0066] Step S3.1: During the Rn+2 period in the crystal rod pulling process, the actual minority carrier lifetime of the crystal rod corresponding to the Rn period in the pulling process can be obtained.

[0067] Specifically, the actual minority carrier lifetime of the crystal rod is one of the key parameters for measuring the quality of semiconductor materials, which can directly affect the conversion efficiency of photovoltaic cells. It is worth noting that in this embodiment, the actual minority carrier lifetime of the crystal rod can be obtained by a variety of measurement methods, including but not limited to microwave photoconductivity attenuation method, quasi-steady-state photoconductivity method, surface photovoltage method, diffusion length method, transient photoconductivity attenuation method and steady-state photoconductivity method.

[0068] Step S3.2: Set the target minority carrier lifetime of the crystal rod corresponding to the Rn period during the pulling process. Specifically, in different production stages or time periods, the setting of the target minority carrier lifetime of the crystal rod will be based on a variety of factors, including but not limited to product quality standards, final application requirements and production process conditions. Usually, the setting of the target minority carrier lifetime is formulated according to the specific requirements of the user or industry standards. For example, in the photovoltaic industry, a higher minority carrier lifetime means better conversion efficiency, so for high-performance solar panels, the target minority carrier lifetime will be set higher.

[0069] Step S3.3: Obtain the difference between the actual minority carrier lifetime corresponding to the Rn period of the crystal rod obtained in step S3.1 and the target minority carrier lifetime corresponding to the Rn period of the crystal rod set in step S3.2, and compare the difference with the preset difference corresponding to the period in which the crystal rod is located, and adjust the circulating material ratio of the crystal rod in the Rn+2 period according to the comparison result. That is to say, after obtaining the weight of the remaining material in the furnace, the automatic feeding control method in this embodiment adjusts the subsequent feeding plan in combination with the set circulating material ratio. That is, by dynamically adjusting the feeding ratio, not only can the quality of the crystal rod in each production period be ensured to be consistent, but also through strict control measures, it can be ensured that the use of circulating materials will not reduce the overall quality of the crystal rod.

[0070] Furthermore, when the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the circulating material ratio is set to the first-level downward adjustment ratio; otherwise, the circulating material ratio is set to the second-level downward adjustment ratio, and the first-level downward adjustment ratio is less than the second-level downward adjustment ratio.

[0071] Specifically, refer to Table 1 below, which corresponds to the specific adjustment range of each recycling material ratio.

[0072] Table 1

[0073]

[0074]

[0075] That is to say, according to Table 1 above, the adjustment of the circulating material ratio can be divided into three cases according to the pulling period of the crystal rod, that is, the R1 period, R2 period and R3 period correspond to the first case, the R4 period, R5 period and R6 period correspond to the second case, and the remaining period corresponds to the third case. At the same time, the specific adjustment corresponding to each case is as follows:

[0076] The first case corresponding to the R1 period, R2 period and R3 period is as follows:

[0077] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is not less than the preset difference of 50, the circulating material ratio is adjusted to 30%-35%, that is, the first-level downward adjustment ratio is set to 30%-35%.

[0078] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is less than the preset difference of 50, the circulating material ratio is adjusted to 40%-50%, that is, the secondary downward adjustment ratio is set to 40%-50%.

[0079] The second situation corresponding to the R4 period, the R5 period and the R6 period is as follows:

[0080] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is not less than the preset difference of 30, the circulating material ratio is adjusted to 30%-35%, that is, the first-level downward adjustment ratio is set to 30%-35%.

[0081] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is less than the preset difference of 30, the proportion of recycled material is adjusted to 45%-50%, that is, the secondary downward adjustment ratio is set to 45%-50%.

[0082] The third situation corresponding to the remaining period is as follows:

[0083] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is not less than the preset difference of 20, the recycling material ratio is adjusted to 40%-50%, that is, the first-level downward adjustment ratio is set to 40%-50%.

[0084] When the difference between the actual minority carrier lifetime of the crystal rod corresponding to the Rn period obtained in step S3.1 and the target minority carrier lifetime of the crystal rod corresponding to the Rn period set in step S3.2 is less than the preset difference of 20, the circulating material ratio is adjusted to 50%-55%, that is, the secondary downward adjustment ratio is set to 50%-55%.

[0085] Specifically, the reuse of recycled materials not only helps save raw materials and reduce production costs, but also reduces the generation of waste, which has positive significance for environmental protection. However, the quality of recycled materials is often inferior to that of original silicon materials. Therefore, in this embodiment, by accurately controlling the mixing ratio of recycled materials, the electrical properties of the crystal rod can be effectively maintained, ensuring that the crystal rod can meet the predetermined quality standards in each production period.

[0086] Step S4: Based on the actual amount D to be added in the single crystal furnace obtained in step S2.1 and successfully verified in step S2.2, and combined with the circulating material ratio determined in step S3.3, the material room prepares the materials.

[0087] In this embodiment, the silicon material barreling scheme is used to load the materials in separate barrels, and a new actual amount to be added is obtained. Specifically, the actual amount to be added can be recalculated, and the silicon material barreling scheme can be used to load the materials in separate barrels. The silicon material barreling scheme stipulates that the maximum value of a single barrel is 110kg and the minimum value is 20kg. Therefore, the total added weight needs to be distributed to multiple barrels so that the weight of each barrel is within the specified range. In this embodiment, the specific allocation method used includes but is not limited to the use of a greedy algorithm and a dynamic programming algorithm.

[0088] It is worth noting that there are many time periods in the process of crystal rod crystallization and pulling. Specifically, due to the intervals between time periods, and the crystal rod corresponding to each time period cannot be obtained immediately, that is, it takes a certain amount of time to obtain. In this embodiment, during the crystal rod crystallization and pulling process, the crystal rod result corresponding to the R1 time period can be obtained during the R3 time period. That is to say, during the crystal rod crystallization and pulling process, the actual amount D to be added in the single crystal furnace corresponding to the R1 time period and the R2 time period is the weight of the material to be added in the furnace obtained in the above step S2. However, the actual amount to be added after the R3 section needs to be set in combination with the circulating material ratio in step S3.

[0089] Specifically, the automatic feeding control method in this embodiment can dynamically adjust the proportion of circulating materials at different stages of single crystal silicon rod pulling to ensure that the minority carrier lifetime of the final product meets the predetermined standard. At the same time, this dynamic adjustment mechanism helps to optimize the production process, reduce waste, and improve the performance of the final product.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automated feeding control method in single crystal silicon manufacturing, characterized in that: The automatic feeding control method comprises the following steps: S1: Obtain the weight of the remaining material in the furnace according to the drawing progress of the crystal rod; S2: Determine the weight of the material to be added to the furnace by the weight of the remaining material in the furnace, and review the weight of the material to be added to the furnace. If the weight of the material to be added to the furnace passes the review, the next step is executed. Otherwise, an alarm is manually processed; S3: obtaining an actual minority carrier lifetime corresponding to the crystal rod in the Rn period, determining a difference between the actual minority carrier lifetime corresponding to the Rn period and a target minority carrier lifetime corresponding to the Rn period, and adjusting a recycling material ratio of the crystal rod in the Rn+2 period according to the difference; S4: The material room prepares materials according to the weight of materials to be added to the furnace and the proportion of circulating materials.

2. The method for controlling the automatic feeding in the production of single crystal silicon according to claim 1, characterized in that: In step S1, the weight of the remaining material in the furnace is obtained as follows: S1.1: Determine the wire breakage after the crystal ingot is drawn according to the drawing progress of the crystal ingot; S1.2: Obtain the weight of the remaining material in the furnace according to the wire breakage condition of the crystal rod after being pulled.

3. The method for controlling the automatic feeding in the production of single crystal silicon according to claim 2, characterized in that: The wire breakage situations after the crystal rod is pulled include but are not limited to taking a section to finish the tail and adding materials, adding materials when the wire is broken, stopping the pulling without adding materials at the end, and re-leading without adding materials when the wire is broken.

4. The method for controlling the automatic feeding in the production of single crystal silicon according to claim 1, characterized in that: In step S2, the weight of the material to be added to the furnace is reviewed as follows: S2.1: Determine the weight of material to be added to the furnace based on the weight of the remaining material in the furnace, specifically: D=Aa-10kg Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and a is the remaining material in the single crystal furnace; S2.2: Set the product retention rate and review the weight of the material to be added to the furnace. The review formula is as follows: ρ×A+15kg≥D Where: D is the actual amount to be added in the single crystal furnace, A is the full pot weight in the single crystal furnace, and ρ is the product pot retention rate; When the review formula is satisfied, the weight of the material to be added to the furnace is reviewed and passed, and the next step is executed. Otherwise, an alarm is manually processed.

5. The method for controlling automatic feeding in the production of single crystal silicon according to claim 1, characterized in that: In step S3, the circulating material ratio of the crystal rod in the Rn+2 period is adjusted as follows: S3.1: Obtain the actual minority carrier lifetime corresponding to the crystal rod in the Rn period by measuring method; S3.2: Set the target minority carrier lifetime corresponding to the crystal rod in the Rn period; S3.3: Obtain the difference between the actual minority carrier lifetime and the target minority carrier lifetime corresponding to the crystal rod in the Rn period, and compare the difference with the preset difference. When the difference is not less than the preset difference, the circulating material ratio is set to the first-level downward adjustment ratio; otherwise, the circulating material ratio is set to the second-level downward adjustment ratio.

6. The method for controlling automatic feeding in the production of single crystal silicon according to claim 5, characterized in that: The measuring methods include, but are not limited to, microwave photoconductivity decay method, quasi-steady-state photoconductivity method, surface photovoltage method, diffusion length method, transient photoconductivity decay method and steady-state photoconductivity method.

7. The method for controlling automatic feeding in the production of single crystal silicon according to claim 5, characterized in that: The first-level downward adjustment ratio is smaller than the second-level downward adjustment ratio.

8. The method for controlling automatic feeding in the production of single crystal silicon according to claim 5, characterized in that: The proportion of the recycled material is divided according to the pulling period of the crystal rod, as follows: The proportion of recycled materials corresponding to the R1 period, R2 period and R3 period is as follows: When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 30%-35%, otherwise, the second-level downward adjustment ratio is set to 40%-50%; The proportion of recycled materials corresponding to the R4 period, R5 period and R6 period is as follows: When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 30%-35%, otherwise, the second-level downward adjustment ratio is set to 45%-50%; The proportion of recycled materials corresponding to the remaining period is as follows: When the difference between the actual minority carrier lifetime and the target minority carrier lifetime is not less than the preset difference, the first-level downward adjustment ratio is set to 40%-50%, otherwise, the second-level downward adjustment ratio is set to 50%-55%.

9. The method for controlling automatic feeding in the production of single crystal silicon according to claim 1, 5 or 8, characterized in that: During the R1 and R2 periods of the crystal rod pulling process, the material room prepares materials according to the weight of materials to be added to the furnace.

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