A method for controlling micro-defects in silicon crystals

Abstract

A method for controlling bulk microdefects (BMDs) within a silicon crystal involves segmenting and measuring the temperature of the drawn constant-diameter segments during the constant-diameter growth process. The measured temperature values ​​of each segment are compared with the standard temperatures of the corresponding segments to select a suitable holding method for each segment, ensuring that the temperature of each segment remains within its standard temperature range. Furthermore, based on the bulk microdefect density (BMD) index of the silicon crystal, the holding time for each segment within its standard temperature range is determined by comparing it with a standard BMD density, thereby obtaining a silicon crystal with a BMD density that meets the specified index. This invention can alter the nucleation degree of oxygen precipitates within different gradient segmented temperature ranges in the silicon crystal, thereby changing the BMD growth pattern and obtaining silicon crystals with different required BMD densities to suit the BMD density requirements of various end products.

Description

Technical Field

[0001] This invention belongs to the field of Czochralski single crystal growth technology, and in particular relates to a method for controlling micro-defects in silicon crystals. Background Technology

[0002] For Czochralski-grown silicon single crystals used in large-scale integrated circuit manufacturing, BMD (Bulk Micro Defect) is generally considered to be supersaturated in interstitial states because oxygen is introduced into the silicon wafer at approximately 1400°C at the melting point. Therefore, within the typical device manufacturing temperature range (≤1200°C), oxygen in this interstitial state is supersaturated. During the thermal cycling of the device manufacturing process, these oxygen impurities precipitate due to decreased solid solubility, potentially inducing secondary defects such as dislocations and stacking faults. Excessive oxygen precipitation can also cause slip and warping, severely impacting device yield. However, this defect also possesses internal gettering properties, effectively removing point defects within the silicon single crystal and heavy metal impurities introduced during device manufacturing, reducing contamination of the surface source region.

[0003] Oxygen precipitates also possess a strong ability to pin dislocations, significantly improving the mechanical strength of silicon wafers. During subsequent thermal cycling, they can largely suppress wafer warpage and increase device yield. These properties are all related to the density of oxygen precipitates generated during the cooling process of silicon single crystals.

[0004] In the aforementioned applications, the BMD of these oxygen precipitates needs to be correlated with and matched to the chip thermal process, rather than simply pursuing excessively low or high BMD. In existing conventional single-crystal growth processes, after the silicon crystal leaves the solid-liquid interface, it sequentially enters the secondary chamber from the main chamber without further operations. This makes it impossible for existing crystal pulling methods to achieve further control over BMD; instead, it is determined by the initial crystal crystallization process. Consequently, it is impossible to control the BMD defect density, causing problems for subsequent chip fabrication processes.

[0005] Therefore, how to dynamically control the BMD density during the single-crystal silicon growth process has become a major problem that needs to be solved in order to improve the quality, utilization rate and yield of semiconductor silicon crystals. Summary of the Invention

[0006] This invention provides a method for controlling bulk microdefects in silicon crystals, which solves the technical problem in the prior art that the density of bulk defects (BMD) cannot be dynamically controlled during the growth of silicon crystals.

[0007] To solve at least one of the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for controlling bulk micro-defects in a silicon crystal, comprising the following steps:

[0009] During the constant-diameter growth process of silicon crystal, the temperature of the pulled-out constant-diameter segment is measured in segments.

[0010] The temperature values ​​of each equal-diameter segment of the silicon crystal are obtained and compared with the standard temperature of the corresponding equal-diameter segment. A suitable heat preservation method is selected for each equal-diameter segment of the silicon crystal so that the temperature of each equal-diameter segment of the silicon crystal is within the standard temperature range of the corresponding segment.

[0011] Based on the bulk microdefect density index of the silicon crystal, and compared with the standard bulk microdefect density, the holding time of the constant diameter section within its standard temperature range is determined to obtain the silicon crystal with a bulk microdefect density that meets the index.

[0012] Furthermore, the selection of a suitable heat preservation method for each equal-diameter segment of the silicon crystal specifically includes:

[0013] The temperature of each segment of the drawn constant diameter section of the silicon crystal was measured along the pulling direction.

[0014] Determine whether the measured temperature of each equal-diameter segment of the silicon crystal is within the standard temperature range of that equal-diameter segment;

[0015] If so, continue to monitor the temperature of that constant-diameter section;

[0016] If the temperature is lower than its standard temperature, then the equal-diameter section is heated.

[0017] If the temperature exceeds its standard temperature, then the equal-diameter section should be cooled.

[0018] The temperature measurement location for each constant-diameter segment is the point closest to the solid-liquid interface within that segment.

[0019] Furthermore, the segmentation of the equal-diameter section of the silicon crystal is determined based on the height corresponding to the nucleation temperature range of point micro-defects and the nucleation temperature range of bulk micro-defects, including a first segment and a second segment connected sequentially from bottom to top along its length direction, with the second segment positioned closer to the head side; the standard temperature of the first segment is greater than the standard temperature of the second segment.

[0020] Furthermore, the first segment is located within a height of 500-900 mm from the solid-liquid interface;

[0021] The second segment is located within a height of 700-1100 mm from the solid-liquid interface.

[0022] Furthermore, the first segment corresponds to the location where the point micro-defect is formed; the second segment corresponds to the location where the volume micro-defect is formed.

[0023] Furthermore, the nucleation temperature range of the point micro-defects is 950-1150℃; the nucleation temperature range of the volume micro-defects is 600-950℃.

[0024] Furthermore, the standard temperature of the first segment is the highest value of the nucleation temperature of the point micro-defect, which is 1150±50℃.

[0025] Furthermore, the standard temperature of the second segment is the highest value of the nucleation temperature of the bulk microdefect, which is 950±50℃.

[0026] Furthermore, determining the insulation time of the equal-diameter section within its standard temperature range specifically includes:

[0027] Control each equal-diameter section within its standard temperature range;

[0028] The index used to determine the bulk microdefect density of the silicon crystal is compared with the index of its standard bulk microdefect density.

[0029] Then, based on the standard heat preservation time of each equal-diameter segment of the silicon crystal, the heat preservation time of each equal-diameter segment of the silicon crystal is adjusted.

[0030] The standard volumetric microdefect density of the silicon crystal is 1E+9-5E+9.

[0031] Furthermore, when the bulk microdefect density of the silicon crystal is greater than its standard bulk microdefect density, the heat preservation time of the first segment is controlled to be less than the standard heat preservation time of the first segment, and the heat preservation time of the second segment is greater than the standard heat preservation time of the second segment.

[0032] Furthermore, when the bulk micro-defect density of the silicon crystal is less than its standard bulk micro-defect density, the heat preservation time of the first segment is controlled to be greater than the standard heat preservation time of the first segment, and the heat preservation time of the second segment is less than the standard heat preservation time of the second segment.

[0033] Furthermore, the standard insulation time for the first segment is 1-3 hours; the standard insulation time for the second segment is 3-5 hours.

[0034] This invention discloses a method for controlling micro-defects within silicon crystals. By monitoring the surface temperature of different equal-diameter segments of the pulled silicon crystal, the heat preservation method of each segment is adjusted. Furthermore, based on the required BMD density of the silicon crystal, the heat preservation time of different equal-diameter segments is selected to alter the nucleation degree of oxygen precipitates within different temperature gradients of the silicon crystal. This dynamically changes the BMD growth, resulting in silicon crystals with different required BMD densities to suit the BMD density requirements of various end products. Attached Figure Description

[0035] Figure 1 This is a flowchart of a method for controlling micro-defects within a silicon crystal according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the silicon crystal pulling state according to an embodiment of the present invention;

[0037] Figure 3 This is a microscopic image of the standard volumetric microdefect density in the NPC standard single crystal of this invention;

[0038] Figure 4 This is a microscopic image of the density of micro-defects in the silicon crystal of Example 1 of this invention;

[0039] Figure 5 This is a microscopic image of the density of micro-defects in the silicon crystal of Example 2 of this invention.

[0040] In the diagram: 10, main chamber; 20, auxiliary chamber; 30, silicon crystal; 31, first segment; 32, second segment; 40, first temperature stabilizing device; 50, second temperature stabilizing device; 60, temperature measuring instrument. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] This embodiment proposes a method for controlling micro-defects within silicon crystals, such as... Figure 1 As shown, the steps include:

[0043] S1. During the constant diameter growth process of silicon crystal 30, the temperature of the drawn constant diameter segment is measured in segments.

[0044] The silicon crystal 30 can be grown using any process, such as CZ, MCZ, and FZ; in this embodiment, the silicon crystal 30 prepared by the CZ method is taken as an example, and the pulled structure is as follows. Figure 2 As shown.

[0045] During the growth of silicon crystal 30, polycrystalline silicon is first melted into molten silicon, and then seed crystals are introduced by fusion bonding with the molten silicon to eliminate dislocations. Growth then proceeds through stages such as shoulder expansion, shoulder rotation, and equal-diameter sections. Defects are always present during the growth of single silicon crystals. In silicon crystal 30, these defects evolve from point defects to micro-defects as the temperature decreases, and then gradually form bulk micro-defects. Because many defects exist at the head of silicon crystal 30 and need to be removed, only the equal-diameter section of silicon crystal 30 is the finished product.

[0046] Specifically, the solid-liquid interface temperature at the start of silicon crystal growth (30) is approximately 1420°C. Since point defects generated at the solid-liquid interface maintain an equilibrium temperature, the gaps and vacancies at the interface are balanced. After solidification, silicon crystal (30) continues to be pulled upwards. As it rises, the constant-diameter section after leaving the solid-liquid interface begins to gradually cool. This section cools from 1400°C initially. At this point, oxygen within the constant-diameter section begins to diffuse outwards, and the gaps and vacancies within the section begin to recombine, forming point defects. When the temperature drops to 1150°C, supersaturated point defects begin to precipitate, forming micro-point defects such as COP, FPD, and LSTD. As the constant-diameter segment of silicon crystal 30 continues to move upwards, the point micro-defects within silicon crystal 30 decrease in temperature from 1150℃ to 950℃. These point micro-defects consume neighboring point defects, causing vacancies to polymerize with oxygen to form oxygen complexes, thus initiating nucleation and growth of the point micro-defects. When the temperature of silicon crystal 30 continues to decrease from 950℃ to 600℃, vacancies and oxygen atoms form oxygen polymers, and the remaining vacancy sites promote the nucleation of oxygen precipitates, forming bulk micro-defects. Therefore, the temperature range for point defects is 1150-1400℃; the nucleation temperature range for point micro-defects is 950-1150℃; and the nucleation temperature range for bulk micro-defects is 600-950℃.

[0047] In this field, semiconductor-grade silicon single crystals are referred to as NPC standard single crystals. The density of bulk microdefects in their constant-diameter segments is the standard bulk microdefect density of silicon crystal 30, which is 1E+9-5E+9. The standard segmentation of the constant-diameter segments of the NPC standard single crystal is the segmentation standard of the constant-diameter segments already pulled from silicon crystal 30. This segmentation standard is determined based on the height corresponding to the nucleation temperature range of point microdefects and the nucleation temperature range of bulk microdefects in silicon crystal 30. That is, the segmentation of the constant-diameter segments of the NPC standard single crystal is the segmentation of the constant-diameter segments of silicon crystal 30, which is the first segment 31 and the second segment 32 connected and divided sequentially from bottom to top along the pulling direction of silicon crystal 30; and the standard temperature of the first segment 31 is higher than the standard temperature of the second segment 32.

[0048] The first segment 31 is located within a height of 500-900 mm from the solid-liquid interface, spanning the main chamber 10 and the secondary chamber 20; the second segment 32 is located within a height of 700-1100 mm from the solid-liquid interface, within the secondary chamber 20 and close to one end of the cavity. Since the nucleation temperature range for point microdefects is 950-1150℃, and the nucleation temperature range for volume microdefects is 600-950℃, the first segment 31 corresponds to the formation location of point microdefects, and the second segment 32 corresponds to the formation location of volume microdefects.

[0049] Since the temperature change of the silicon crystal 30 is from high to low, the initial nucleation temperature for point defects to form micro-defects after entering the first segment 31 should be the highest temperature value of the point micro-defects; correspondingly, the initial nucleation temperature for point micro-defects to form bulk micro-defects after entering the second segment 32 should be the highest temperature value of the bulk micro-defects. Meanwhile, since the nucleation temperatures have a certain range of variation, and to improve the accuracy of the nucleation temperatures, the standard temperature of the first segment 31 is set as the maximum nucleation temperature of point micro-defects, which is 1150±50℃; the standard temperature of the second segment 32 is set as the maximum nucleation temperature of bulk micro-defects, which is 950±50℃; this ensures that the temperatures entering the first segment 31 and the second segment 32 are reasonable and controllable. Therefore, the temperature measurement point for each equal-diameter segment of the silicon crystal 30 should be the temperature of the point closest to the solid-liquid interface within that segment. That is, the temperature measurement point for the first segment 31 is the lowest point of the first segment 31, and monitoring the inlet temperature of the first segment 31 is its measured temperature. Similarly, the temperature measurement point for the second segment 32 is the lowest point of the second segment 32, and monitoring the inlet temperature of the second segment 32 is its measured temperature. A commonly used infrared thermometer is used for temperature measurement; that is, a thermometer 60 is installed at the lowest point of both the first and second segments 31 to measure the temperature of the equal-diameter segments of both segments.

[0050] For NPC standard single crystals, point microdefects are extremely unstable at high temperatures, resulting in rapid nucleation and a shorter nucleation time. Conversely, bulk microdefects nucleate and grow at lower temperatures, requiring more time. Therefore, for semiconductor-grade silicon crystals, if the nucleation temperature of point microdefects in the first segment 31 is consistently within the range of 950-1150℃ with a holding time of 1-3 hours, and the nucleation temperature of bulk microdefects in the second segment 32 is consistently within the range of 600-950℃ with a holding time of 3-5 hours, then an NPC standard single crystal with a standard bulk microdefect density of 1E+9-5E+9 can be obtained. That is, the standard holding time T1 for the first segment 31 is 1-3 hours, the standard holding time T2 for the second segment 32 is 3-5 hours, and the standard bulk microdefect density is 1E+9-5E+9.

[0051] S2. Obtain the temperature values ​​of each equal-diameter segment of the silicon crystal 30, compare them with the standard temperature of the corresponding equal-diameter segment, and select a suitable heat preservation method for each equal-diameter segment of the silicon crystal 30 so that the temperature of each equal-diameter segment of the silicon crystal 30 is within the standard temperature range of the corresponding segment.

[0052] Specifically, it includes:

[0053] The temperature of each segment was measured along the pulling direction of the 30mm diameter section of the silicon crystal.

[0054] The temperature measuring instruments 60, which are respectively installed in the first segment 31 and the second segment 32, are used to obtain the measured values ​​of the first segment 31 and the second segment 32 in sequence.

[0055] To ensure the temperature of the silicon crystal 30 within the corresponding segments, a first temperature stabilizing device 40 and a second temperature stabilizing device 50 are sequentially installed within the height range of the first segment 31 and the second segment 32, respectively. Both the first temperature stabilizing device 40 and the second temperature stabilizing device 50 have heating and cooling functions. Heating can be achieved using electromagnetic induction heating or water heating through copper pipes; cooling can be achieved using circulating cold water pipes or cooling with inert gas. Regardless of the method, as long as it has heating and cooling functions, it is acceptable. This is a conventional device in the art, and its structure is omitted here. The first temperature stabilizing device 40 and the second temperature stabilizing device 50 are located within the height range of the first segment 31 and the second segment 32, respectively, and their height range is 50-150 mm.

[0056] Determine whether the measured temperature of each equal-diameter section is within the standard temperature range for that equal-diameter section.

[0057] The silicon crystal 30 rises steadily and gradually at a constant pulling speed. Regardless of which segment of the silicon crystal 30 it is, it must pass through the first segment 31 and the second segment 32 in sequence. In the first segment 31 and the second segment 32, the constant diameter segment of the silicon crystal 30 is monitored simultaneously.

[0058] If the measured temperature is within the standard temperature range, temperature monitoring will continue for that equal-diameter section. That is, if the measured temperature of the first segment 31 is within the range of 1150±50℃ or the measured temperature of the second segment 32 is within the range of 950±50℃, temperature monitoring will continue.

[0059] If the measured temperature is lower than its standard temperature, the equal-diameter section is heated. If the measured temperature of the first section 31 is less than 1150±50℃, the first insulation device 40 is controlled to heat the first section 31 to make its temperature meet the standard temperature requirement. If the measured temperature of the second section 32 is less than 950±50℃, the second insulation device 50 is controlled to heat the second section 32 to make its temperature meet the standard temperature requirement.

[0060] If the measured temperature is higher than its standard temperature, the equal-diameter section is cooled. If the measured temperature of the first section 31 is greater than 1150±50℃, the first insulation device 40 is controlled to cool the first section 31 to bring its temperature to the standard temperature requirement. If the measured temperature of the second section 32 is greater than 950±50℃, the second insulation device 50 is controlled to cool the second section 32 to bring its temperature to the standard temperature requirement.

[0061] S3. Based on the bulk micro-defect density index of silicon crystal 30, compare it with the standard bulk micro-defect density to determine the heat preservation time of the equal diameter section within its standard temperature range, so as to obtain silicon crystal 30 with a bulk micro-defect density that meets the index.

[0062] The required bulk microdefect density varies depending on the type of silicon wafer used.

[0063] First, control each equal-diameter section within its standard temperature range, that is, ensure that the measured temperature of the first section 31 is within 1150±50℃ and the measured temperature of the second section 32 is within 950±50℃. This will ensure that the overall temperature of the first section 31 is within the range of 950-1150℃ and the overall temperature of the second section 32 is within the range of 600-950℃.

[0064] By comparing the target index of the bulk micro-defect density of silicon crystal 30 with the standard bulk micro-defect density 1E+9-5E+9, and based on the standard heat preservation time of each equal-diameter segment of silicon crystal 30, the heat preservation time of each equal-diameter segment of silicon crystal 30 is adjusted.

[0065] When the bulk micro-defect density of silicon crystal 30 is greater than the standard bulk micro-defect density 1E+9-5E+9, the holding time t1 of the first segment 31 is controlled to be less than the standard holding time T1 of the first segment 31, and the holding time t2 of the second segment 32 is controlled to be greater than the standard holding time T2 of the second segment 32. That is, the first holding device 40 is controlled to keep the temperature of the first segment 31 within the range of 950-1150℃, and the second holding device 50 is controlled to keep the temperature of the second segment 32 within the range of 600-950℃. Furthermore, compared to the standard holding time, the holding time t1 of the first segment 31 is shortened, and the holding time t2 of the second segment 32 is increased. This reduces the nucleation time of point micro-defects and increases the nucleation time of bulk micro-defects, thereby obtaining a greater number of bulk micro-defects and thus obtaining a silicon crystal 30 with a higher bulk micro-defect density than the standard bulk micro-defect density.

[0066] When the bulk micro-defect density of silicon crystal 30 is less than its standard bulk micro-defect density 1E+9-5E+9, the holding time t1 of the first segment 31 is controlled to be greater than the standard holding time T1 of the first segment 31, and the holding time t2 of the second segment 32 is less than the standard holding time T2 of the second segment 32. That is, the first holding device 40 is controlled to keep the temperature of the first segment 31 within the range of 950-1150℃, and the second holding device 50 is controlled to keep the temperature of the second segment 32 within the range of 600-950℃. Furthermore, compared to the standard holding time, extending the holding time t1 of the first segment 31 and shortening the holding time t2 of the second segment 32 increases the nucleation time of point micro-defects and shortens the nucleation time of bulk micro-defects, thereby obtaining a smaller number of bulk micro-defects and thus obtaining a silicon crystal 30 with a lower bulk micro-defect density than the standard bulk micro-defect density.

[0067] To enable those skilled in the art to further understand the method of the present invention, the technical solution of the present invention will be explained in detail below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1:

[0068] S1. During the constant diameter growth process of silicon crystal 30, the first segment 31 and the second segment 32 of the drawn constant diameter section are measured in segments, and the measured temperature of the first segment 31 is 1120℃ and the measured temperature of the second segment 32 is 960℃.

[0069] S2. Since the measured temperature values ​​of the first segment 31 and the second segment 32 are both within their standard temperature ranges, there is no need to heat or cool the first segment 31 and the second segment 32.

[0070] The target index for the iron micro-defect density of S3 and silicon crystal 30 is 5E+10, which is greater than the standard micro-defect density of 1E+9-5E+9.

[0071] Then the first heat preservation device 40 is controlled to keep the temperature of the first segment 31 within the range of 950-1150℃, and the heat preservation time t1 of the first segment 31 is set to 50% of the standard heat preservation time T1 of the first segment 31.

[0072] Furthermore, the second insulation device 50 is controlled to keep the temperature of the second section 32 within the range of 600-950℃, and the insulation time t2 of the second section 32 is 3 hours longer than the standard insulation time T2 of the second section 32.

[0073] In this embodiment, the nucleation time of point microdefects is reduced and the nucleation time of bulk microdefects is increased to obtain a greater number of bulk microdefects, thereby obtaining a silicon crystal 30 with a higher bulk microdefect density than the standard bulk microdefect density. The final microstructure of the silicon crystal 30 is shown in the figure below. Figure 4 As shown; and as Figure 3 Compared to the microscopic image of silicon crystal 30 with standard bulk microdefect density shown, the number of bulk microdefects in this embodiment is greater. Example 2:

[0074] S1. During the constant diameter growth process of silicon crystal 30, the first segment 31 and the second segment 32 of the drawn constant diameter section are measured in segments, and the measured temperature of the first segment 31 is 1250℃ and the measured temperature of the second segment 32 is 800℃.

[0075] S2. If the measured temperature value of the first segment 31 is greater than the standard temperature value of the first segment 31, then the first heat preservation device 40 is controlled to turn on the cooling function to reduce the temperature of the first segment 31 and keep its temperature within 950-1150℃.

[0076] If the measured temperature value of the second segment 32 is less than the standard temperature value of the second segment 32, the second heat preservation device 50 is controlled to turn on the heating function to increase the temperature of the second segment 31 and keep it within 600-950℃.

[0077] The target index for the iron micro-defect density of S3 and silicon crystal 30 is 1E+5, which is less than the standard micro-defect density of 1E+9-5E+9.

[0078] Then the first heat preservation device 40 is controlled to keep the temperature of the first segment 31 within the range of 950-1150℃, and the heat preservation time t1 of the first segment 31 is twice the standard heat preservation time T1 of the first segment 31.

[0079] Furthermore, the second insulation device 50 is controlled to keep the temperature of the second section 32 within the range of 600-950℃, and the insulation time t2 of the second section 32 is 70% of the standard insulation time T2 of the second section 32.

[0080] In this embodiment, the nucleation time of point microdefects is increased while the nucleation time of bulk microdefects is decreased to obtain a smaller number of bulk microdefects, thereby obtaining a silicon crystal 30 with a lower bulk microdefect density than the standard bulk microdefect density. The final microstructure of the obtained silicon crystal 30 is shown in the figure below. Figure 5 As shown; and as Figure 3 Compared to the microscopic image of silicon crystal 30 with standard bulk microdefect density shown, the number of bulk microdefects in this embodiment is small.

[0081] This invention discloses a method for controlling micro-defects within silicon crystals, applicable to silicon crystals grown using CZ, MCZ, and FZ processes. By monitoring the surface temperature of different equal-diameter segments of the pulled silicon crystal, the heat preservation method for each segment is adjusted. Furthermore, based on the required BMD density of the silicon crystal, the heat preservation time for different equal-diameter segments is selected to alter the nucleation degree of oxygen precipitates within different temperature gradients of the silicon crystal. This dynamically changes the BMD growth, resulting in silicon crystals with varying required BMD densities to suit the BMD densities required for different end products.

[0082] The embodiments of the present invention have been described in detail above. These descriptions are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for controlling micro-defects within a silicon crystal, characterized by the following steps: include: During the constant diameter growth process of silicon crystal, the pulled constant diameter segment is segmented for temperature measurement. The segmentation is determined based on the height corresponding to the nucleation temperature range of point micro-defects and the nucleation temperature range of bulk micro-defects, including a first segment and a second segment connected sequentially from bottom to top along its length direction. The temperature values ​​of each equal-diameter segment of the silicon crystal are obtained and compared with the standard temperature of the corresponding equal-diameter segment. The standard temperature of the first segment is the highest value of the nucleation temperature of the point micro-defect, which is 1150±50℃; the standard temperature of the second segment is the highest value of the nucleation temperature of the bulk micro-defect, which is 950±50℃. Select a suitable heat preservation method for each equal-diameter segment of the silicon crystal so that the temperature of each equal-diameter segment of the silicon crystal is within the standard temperature range of the corresponding segment. Based on the bulk microdefect density index of the silicon crystal, it is compared with the standard bulk microdefect density, wherein the standard bulk microdefect density of the silicon crystal is 1E+9-5E+9; the heat preservation time of the constant diameter section within its standard temperature range is determined to obtain the silicon crystal with a bulk microdefect density that meets the index. The standard insulation time for the first segment is 1-3 hours; the standard insulation time for the second segment is 3-5 hours.

2. The method for controlling micro-defects within a silicon crystal according to claim 1, characterized in that, The selection of a suitable heat preservation method for each equal-diameter segment of the silicon crystal specifically includes: The temperature of each segment of the drawn constant diameter section of the silicon crystal was measured along the pulling direction. Determine whether the measured temperature of each equal-diameter segment of the silicon crystal is within the standard temperature range of that equal-diameter segment; If so, continue to monitor the temperature of that constant-diameter section; If the temperature is lower than its standard temperature, then the equal-diameter section is heated. If the temperature exceeds its standard temperature, then the equal-diameter section should be cooled. The temperature measurement location for each constant-diameter segment is the point closest to the solid-liquid interface within that segment.

3. A method for controlling micro-defects within a silicon crystal according to claim 1 or 2, characterized in that, The first segment is located within a height of 500-900 mm from the solid-liquid interface; The second segment is located within a height of 700-1100 mm from the solid-liquid interface.

4. The method for controlling micro-defects within a silicon crystal according to claim 3, characterized in that, The first segment corresponds to the location where the point micro-defect is formed; the second segment corresponds to the location where the volume micro-defect is formed.

5. The method for controlling micro-defects within a silicon crystal according to claim 4, characterized in that, The nucleation temperature range of the point micro-defects is 950-1150℃; the nucleation temperature range of the volume micro-defects is 600-950℃.

6. The method for controlling micro-defects within a silicon crystal according to claim 1, characterized in that, The determination of the insulation time for the equal-diameter section within its standard temperature range specifically includes: Control each equal-diameter section within its standard temperature range; The index used to determine the bulk microdefect density of the silicon crystal is compared with the magnitude of its standard bulk microdefect density; Then, based on the standard heat preservation time of each equal-diameter segment of the silicon crystal, the heat preservation time of each equal-diameter segment of the silicon crystal is adjusted.

7. The method for controlling micro-defects within a silicon crystal according to claim 6, characterized in that, When the bulk microdefect density of the silicon crystal is greater than its standard bulk microdefect density, the heat preservation time of the first segment is controlled to be less than the standard heat preservation time of the first segment, and the heat preservation time of the second segment is greater than the standard heat preservation time of the second segment.

8. The method for controlling micro-defects within a silicon crystal according to claim 7, characterized in that, When the bulk microdefect density of the silicon crystal is less than its standard bulk microdefect density, the heat preservation time of the first segment is controlled to be greater than the standard heat preservation time of the first segment, and the heat preservation time of the second segment is less than the standard heat preservation time of the second segment.

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