Crystal pulling growth control method
By adjusting the region melting voltage and supply speed of the polycrystalline silicon rod in real time, and automatically adjusting the parameters according to the shape deviation of the single crystal silicon, the problems of low standardization and large yield fluctuations caused by human interference in traditional processes are solved, and the growth of single crystal silicon is improved Efficiency and yield.
Patent Information
- Application Number
- CN202411662185.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-01-10
AI Technical Summary
During the growth of single crystal silicon, traditional manual control processes are more disturbed by human factors, resulting in low standardization, large fluctuations in crystal yields, difficulty in developing on a large scale, and slow improvement in efficiency.
By setting the region melting voltage P and supply speed VP of the polycrystalline silicon rod, and obtaining the diameter and cone height of the single crystal silicon in real time, calculating the deviation amount Δh, adjusting the supply speed VP and region melting voltage P to achieve automatic single crystal silicon Grow, ensuring that its shape is close to the theoretical standard shape.
The growth efficiency and crystal yield of single crystal silicon are improved, the automatic growth of single crystal silicon is achieved, artificial interference is reduced, and the consistency and quality of the product are improved.
Smart Images
Figure CN119287494A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a method for controlling crystal growth. Background Art
[0002] In the growth process of single crystal silicon, the zone melting method is a process that uses a high-frequency magnetic field to heat polycrystalline silicon rods, melts local areas into molten silicon, and then cools and solidifies to grow into single crystal silicon. The zone melting method is also called the floating zone melting method. Because it does not directly contact other impurity sources, the crystal impurity content is extremely low, and the purity and quality are excellent. However, the process of the zone melting method increases with the size of the single crystal silicon. There are many influencing factors in the growth process of large-size single crystal silicon. The traditional manual control process is more interfered by human factors, has a low degree of standardization, and the crystal yield fluctuates greatly. It is difficult to develop on a large scale, and the efficiency and yield increase slowly and fluctuate greatly. Summary of the invention
[0003] The purpose of the present application is to provide a crystal pulling growth control method, which can improve the growth efficiency of single crystal silicon and improve the crystal yield.
[0004] The present application provides a method for controlling crystal growth, including:
[0005] Set the melting zone voltage P and supply speed V of the polysilicon rod P , so that the polycrystalline silicon rods are zone melted to form single crystal silicon;
[0006] Obtaining a single crystal silicon diameter d and a single crystal silicon cone height h of the single crystal silicon in each time period T;
[0007] According to the diameter d of the single crystal silicon, a theoretical crystal cone height h0 is obtained;
[0008] Subtract the height h of the single crystal silicon cone from the theoretical crystal cone height h0 to obtain a deviation Δh;
[0009] According to the deviation Δh, the supply speed V is adjusted. P and the zone melting voltage P to achieve the single crystal silicon growth.
[0010] In some embodiments, the step of obtaining the theoretical crystal cone height h0 according to the single crystal silicon diameter d comprises:
[0011] According to the diameter d of the single crystal silicon, the growth rate V of the single crystal silicon is obtained. S ;
[0012] According to the growth rate V of the single crystal silicon S , obtain the crystal theoretical cone height h0.
[0013] In some embodiments, the growth rate V of the single crystal silicon is obtained according to the diameter d of the single crystal silicon. S The steps include:
[0014] A first theoretical function is established, wherein the expression of the first theoretical function is: Where d0 represents the theoretical equivalent diameter of the crystal, V S0 represents the theoretical growth rate of the crystal, d1 represents the standard diameter of the crystal, V S1 represents the standard growth rate of the first crystal, D represents the standard equal diameter of the crystal, V SD represents the standard growth rate of the second crystal, and H represents the standard cone height of the crystal;
[0015] Let d0 = d, and obtain the corresponding growth rate V of the single crystal silicon through the first theoretical function. S0 , the growth rate V S =V S0 .
[0016] In some embodiments, according to the growth rate V of the single crystal silicon S , the steps of obtaining the crystal theoretical cone height h0 include:
[0017] A second theoretical function is established, and the expression of the second theoretical function is:
[0018] Let V S0 =V S And through the second theoretical function, the crystal theoretical cone height h0 is obtained.
[0019] In some embodiments, the polycrystalline silicon rod has a polycrystalline silicon rod diameter D0, and in the process of zone melting the polycrystalline silicon rod to form single crystal silicon, the volume of the melted polycrystalline silicon rod and the volume of the formed single crystal silicon satisfy: Among them, V S represents the growth rate of single crystal silicon, K1 represents the correction coefficient of the growth time of single crystal silicon, and t represents the growth time of single crystal silicon.
[0020] In some embodiments, the supply speed V P Satisfaction: V P =V P1 +ΔV P2 , where V P1 Indicates the supply speed V P The first correction value, ΔV P2 Indicates the supply speed V P The second correction value of .
[0021] In some embodiments, the first correction value VP1 satisfy:
[0022] In some embodiments, the supply speed V is obtained according to the deviation Δh. P The second correction value ΔV P2 ,
[0023] The second correction value ΔV P2 satisfy: Among them, K p Represents proportional gain; T t represents the integral time constant; T D represents the differential time constant.
[0024] In some embodiments, the zone melting voltage P satisfies: P n =P n-1 +ΔP, where n is an integer greater than or equal to 2, P n is the zone melting voltage of the polysilicon rod at the nth time period T, P n-1 is the zone melting voltage of the polysilicon rod in the n-1th time period T, and ΔP is the change of the zone melting voltage P between two adjacent time periods.
[0025] In some embodiments, the variation ΔP of the zone melting voltage P satisfies: Wherein, K2 represents the correlation coefficient between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP.
[0026] In some embodiments, a correlation coefficient K2 between a change in the volume of the polycrystalline silicon rod and a change in the zone melting voltage P ΔP ranges from 0 to 10.
[0027] In some embodiments, the correction coefficient K1 of the growth time ranges from 0 to 3.
[0028] In some embodiments, the time period T ranges from 0.2 to 300 seconds.
[0029] The beneficial effects of this application are:
[0030] The present application provides a method for controlling crystal growth, comprising: setting a zone melting voltage P and a supply speed V of a polycrystalline silicon rod; p , so that the polycrystalline silicon rod is zone melted to form single crystal silicon; obtain the single crystal silicon diameter d and the single crystal silicon cone height h of the single crystal silicon in each time period T; obtain the crystal theoretical cone height h0 according to the single crystal silicon diameter d; subtract the single crystal silicon cone height h from the crystal theoretical cone height h0 to obtain the deviation Δh; adjust the supply speed V according to the deviation Δh Pand zone melting voltage P to achieve the growth of single crystal silicon. During the growth of single crystal silicon, the single crystal silicon diameter d is the actual growth diameter of the single crystal silicon, the single crystal silicon cone height h is the actual cone height of the single crystal silicon corresponding to the actual growth diameter of the single crystal silicon, and the crystal theoretical equal diameter d0 is the theoretical equal diameter of the single crystal silicon. In the process of single crystal silicon growing from seed crystal to crystal standard equal diameter D, in each time period T, the single crystal silicon diameter d and the single crystal silicon cone height h, as well as the deviation Δh between the single crystal silicon diameter d and the crystal theoretical equal diameter d0, can reflect the actual shape of the single crystal silicon during the growth process. By comparing the actual shape of the single crystal silicon with the theoretical shape, the data signal of the deviation Δh can be used to adjust the supply speed V of the polycrystalline silicon rod. p and zone melting voltage P to achieve automatic growth of single crystal silicon. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 A schematic diagram of the structure of the crystal pulling growth provided in this application;
[0032] Figure 2 A schematic diagram of the structure of the single crystal silicon provided in this application;
[0033] Figure 3 A flow chart of the crystal pulling growth control method provided in this application;
[0034] Figure 4 A schematic diagram of a method for obtaining a deviation Δh in the crystal pulling growth control method provided in the present application;
[0035] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0036] 10. Polycrystalline silicon rod; 20. Seed crystal; 30. Single crystal silicon. DETAILED DESCRIPTION
[0037] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments and drawings of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) within the indicated range.
[0038] like Figure 1-2 As shown, the polycrystalline silicon rod 10 is zone melted, and then the seed crystal 20 is melted into the melted area of the polycrystalline silicon rod 10. The melt will be suspended between the seed crystal 20 and the polycrystalline silicon rod 10 by the surface tension of the molten crystal. As time goes by, the molten crystal near one end of the seed crystal 20 can solidify to form a single crystal silicon 30 with the same crystal orientation as the seed crystal 20.
[0039] By setting a standard crystal shape for the single crystal silicon 30 and establishing a theoretical shape, the growth parameters during the growth of the single crystal silicon 30, such as the zone melting voltage P and the supply speed V of the polycrystalline silicon rod 10, are adjusted. p , and the growth rate V of the single crystal silicon 30 S Adjustment is performed to achieve that the actual growth shape of the single crystal silicon 30 is close to the standard shape of the crystal. P is the traveling speed of the polycrystalline silicon rod 10 along the axial direction Y, and the growth speed V of the single crystal silicon 30 S is the traveling speed of the single crystal silicon 30 along the axial direction Y.
[0040] like Figure 3 As shown, the embodiment of the present application provides a method for controlling crystal growth, comprising:
[0041] Step S1: Setting the zone melting voltage P and supply speed V of the polycrystalline silicon rod 10 P , so that the polycrystalline silicon rod 10 is zone-melted to form a single crystal silicon 30;
[0042] Step S2: obtaining the single crystal silicon diameter d and the single crystal silicon cone height h of the single crystal silicon 30 in each time period T;
[0043] Step S3: Obtaining the theoretical crystal cone height h0 according to the single crystal silicon diameter d;
[0044] Step S4: subtract the single crystal silicon cone height h from the crystal theoretical cone height h0 to obtain a deviation Δh;
[0045] Step S5 : According to the deviation Δh, the supply speed VP and the zone melting voltage P are adjusted to achieve the growth of the single crystal silicon 30 .
[0046] like Figure 4 As shown, it can be understood that, during the growth process of the single crystal silicon 30, the single crystal silicon diameter d is the actual growth diameter of the single crystal silicon 30, the single crystal silicon cone height h is the actual cone height of the single crystal silicon 30 corresponding to the actual growth diameter of the single crystal silicon 30, and the crystal theoretical equal diameter d0 is the theoretical equal diameter of the single crystal silicon 30. In the process of the single crystal silicon 30 growing from the seed crystal 20 to the crystal standard equal diameter D, in each time period T, the single crystal silicon diameter d and the single crystal silicon cone height h, as well as the deviation Δh between the single crystal silicon diameter d and the crystal theoretical equal diameter d0, can reflect the actual shape of the single crystal silicon 30 during the growth process of the single crystal silicon 30. By comparing the actual shape of the single crystal silicon 30 with the theoretical shape and using the data signal of the deviation Δh, the supply speed V of the polycrystalline silicon rod 10 can be adjusted. p and zone melting voltage P to achieve automatic growth of single crystal silicon 30.
[0047] In some embodiments, the single crystal silicon diameter d and the single crystal silicon cone height h can be measured and output in real time by a visual testing system.
[0048] In some embodiments, the step of obtaining the theoretical crystal cone height h0 according to the single crystal silicon diameter d includes:
[0049] According to the diameter d of the single crystal silicon, the growth rate V of the single crystal silicon 30 is obtained. S ;
[0050] According to the growth rate V of the single crystal silicon 30 S , obtain the crystal theoretical cone height h0.
[0051] It can be understood that the growth rate V of the single crystal silicon 30 is S is the speed of the single crystal silicon 30 running along the axial direction Y, which directly affects the growth of the single crystal silicon diameter d. The growth speed V of the single crystal silicon 30 can be calculated by the single crystal silicon diameter d. S , and adjust and set according to this value; through the growth rate V of the single crystal silicon 30 S , the theoretical equivalent diameter d0 of the crystal can be obtained.
[0052] In some embodiments, the growth rate V of the single crystal silicon 30 is obtained according to the diameter d of the single crystal silicon. SThe steps include:
[0053] A first theoretical function is established, wherein the expression of the first theoretical function is: Where d0 represents the theoretical equivalent diameter of the crystal, V S0 represents the theoretical growth rate of the crystal, d1 represents the standard diameter of the crystal, V S1 represents the standard growth rate of the first crystal, D represents the standard equal diameter of the crystal, V SD represents the standard growth rate of the second crystal, and H represents the standard cone height of the crystal;
[0054] Let d0 = d, and obtain the corresponding growth rate V of the single crystal silicon 30 through the first theoretical function: S , then the growth rate V corresponding to the diameter d of the single crystal silicon at this time S =V S0 .
[0055] It can be understood that the first crystal standard growth rate V S1 The growth rate corresponding to the crystal diameter is the crystal standard diameter d1, and the crystal standard diameter d1 and the first crystal standard growth rate V S1 As the first boundary condition of the first theoretical function, the second crystal standard growth rate V SD The growth rate corresponding to the crystal diameter is the crystal standard equal diameter D, and the crystal standard equal diameter D is the second crystal standard growth rate V SD As well as the crystal standard cone height H as the second boundary condition of the first theoretical function, the crystal theoretical growth rate V is established S0 Regarding the first theoretical function of the crystal theoretical equal diameter d0, the single crystal silicon diameter d is substituted into the first theoretical function as the crystal theoretical cone height d0 to obtain the corresponding growth rate V of the single crystal silicon 30 S .
[0056] In some embodiments, the standard crystal diameter d1 ranges from 30 to 100 mm, and the first crystal standard growth rate V S1 The range of the first crystal standard growth rate V is 3 to 6 mm / min. Specifically, the crystal standard diameter d1 can be any one of 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm, or a range consisting of any two values; the first crystal standard growth rate V S1 It can be any one of 3 mm / min, 3.5 mm / min, 4 mm / min, 4.5 mm / min, 5 mm / min, 5.5 mm / min, and 6 mm / min, or a range consisting of any two of the values.
[0057] It can be understood that the standard crystal diameter d1 is generally in the range of 30 to 100 mm, which is mainly related to the measurement accuracy of the visual system and the target single crystal equal diameter to be pulled. The first crystal standard growth rate V S1 The range is 3 to 6 mm / min, which is mainly related to the target single crystal equal diameter to be pulled.
[0058] In some embodiments, the standard equal diameter D of the crystal is in the range of 60 to 300 mm, and the second crystal standard growth rate V SD The range of the crystal standard cone height H is 0.5-3 mm / min, and the range of the crystal standard cone height H is 100-1500 mm. Specifically, the crystal standard equal diameter D can be any one of 60 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm or a range consisting of any two values; the second crystal standard growth rate V SD It can be any one of 0.5 mm / min, 1 mm / min, 1.5 mm / min, 2 mm / min, 2.5 mm / min, and 3 mm / min, or a range consisting of any two of the values.
[0059] It can be understood that the standard crystal diameter D ranges from 60 to 300 mm and the second crystal standard growth rate V SD The range is 100 to 1500 mm, which is mainly related to the equal-diameter diameter of the target single crystal to be pulled.
[0060] In some embodiments, according to the growth rate V of the single crystal silicon 30 S , the steps of obtaining the theoretical cone height h0 of the crystal include:
[0061] The second theoretical function is established, and the expression of the second theoretical function is:
[0062]
[0063] Let V S0 =V S And through the second theoretical function, the crystal theoretical cone height h0 is obtained.
[0064] It can be understood that the crystal standard diameter d1 and the first crystal standard growth rate V S1 As the first boundary condition, the crystal standard equal diameter D and the second crystal standard growth rate V SD As the second boundary condition, the theoretical crystal cone height h0 is established with respect to the theoretical crystal growth rate V S0 The second theoretical function is to convert the growth rate V of single crystal silicon 30 S As the theoretical crystal growth rate V S0Substituting into the second theoretical function, the crystal theoretical cone height h0 can be obtained.
[0065] In some embodiments, the polycrystalline silicon rod 10 has a polycrystalline silicon rod diameter D0. In the process of zone melting the polycrystalline silicon rod 10 to form the single crystal silicon 30, the volume of the melted polycrystalline silicon rod 10 and the volume of the formed single crystal silicon 30 satisfy: Among them, V S represents the growth rate of the single crystal silicon 30 , K1 represents the correction coefficient of the growth time of the single crystal silicon 30 , and t represents the growth time of the single crystal silicon 30 .
[0066] It can be understood that the diameter D0 of the polycrystalline silicon rod remains constant during the growth of the single crystal silicon 30. In the process of zone melting the polycrystalline silicon rod 10 to form the single crystal silicon 30, the volume of the melted polycrystalline silicon rod 10 and the volume formed by the single crystal silicon 30 satisfy the volume conservation relationship. However, in the actual growth process of the single crystal silicon 30, there is a certain time difference between the solidification of the molten polycrystalline silicon rod 10 into the solid single crystal silicon 30, which leads to the actual setting of the supply speed V of the polycrystalline silicon rod 10. P When the growth time of the single crystal silicon 30 is increased, a correction factor K1 is required.
[0067] In some embodiments, the supply speed V P Satisfaction: V P =V P1 +ΔV P2 , where V P1 Indicates the supply speed V P The first correction value, ΔV P2 Indicates the supply speed V P The second correction value.
[0068] It is understandable that, in the actual growth process of the single crystal silicon 30, there is a certain time difference between the solidification of the molten polycrystalline silicon rod 10 into the solid single crystal silicon 30, and the supply speed V P It is necessary to make corrections so that the supply speed V P With the first correction value V P1 In addition, there is a deviation Δh between the single crystal silicon cone height h and the crystal theoretical cone height h0. The deviation Δh can be used as the polycrystalline silicon rod supply speed V P The control signal is corrected by the standard PID (Proportional Integral Differential) mathematical formula, so that the supply speed V P With a second correction value ΔV P2 , so the supply speed V P Meet V P =V P1 +ΔV P2 , and adjust the settings according to this value.
[0069] In some embodiments, the standard PID mathematical formula is: Among them, K p Represents proportional gain; T t represents the integral time constant; T D represents the differential time constant; u(t) represents the output signal of the PID controller; e(t) represents the deviation between the given standard value and the measured value.
[0070] In some embodiments, the proportional gain K p The range is 0 to 2, the integral time constant The range is 0 to 1, and the differential time constant T D The range of is 0 to 1. Specifically, the proportional gain K p It can be any value among 0, 0.5, 1, 1.5, 2 or a range consisting of any two values; the integral time constant It can be any one of 0, 0.2, 0.4, 0.6, 0.8, 1 or a range consisting of any two values; the differential time constant T D It can be any value among 0, 0.2, 0.4, 0.6, 0.8, 1, or a range consisting of any two values.
[0071] It is understandable that the parameter adjustment of PID is related to factors such as the size of the polysilicon rod diameter D0 and the capacity of the equipment, and different value combinations will produce different degrees of signal output.
[0072] In some embodiments, the first correction value V P1 satisfy:
[0073] It is understandable that in the actual growth process of the single crystal silicon 30, there is a certain time difference between the solidification of the molten polycrystalline silicon rod 10 into the solid single crystal silicon 30, so it is necessary to introduce a correction coefficient K1 of the growth time of the single crystal silicon 30 to the supply speed V P Correction is required, the first correction value V P1 satisfy:
[0074] In some embodiments, the supply speed V is obtained according to the deviation Δh. P The second correction value ΔV P2 ,
[0075] Second correction value ΔV P2 satisfy: Among them, K p Represents proportional gain; T t represents the integral time constant; T D Represents the differential time constant.
[0076] It can be understood that there is a deviation Δh between the single crystal silicon cone height h and the crystal theoretical cone height h0, and the deviation Δh can be used as the polycrystalline silicon rod supply speed V P Through the PID correction control signal, the supply speed V P With a second correction value ΔV P2 , the second correction value ΔV P2 satisfy:
[0077] In some embodiments, the zone melting voltage P satisfies: P n =P n-1 +ΔP, where n is an integer greater than or equal to 2, P n is the zone melting voltage of the polysilicon rod 10 during the nth time period T, P n-1 is the zone melting voltage of the polysilicon rod 10 in the n-1th time period T, and ΔP is the variation of the zone melting voltage P between two adjacent time periods.
[0078] In some embodiments, the variation ΔP of the zone melting voltage P satisfies: Wherein, K2 represents the correlation coefficient between the change in volume of the polycrystalline silicon rod 10 and the change in the zone melting voltage P ΔP.
[0079] It can be understood that the zone melting voltage P is mainly related to the diameter D0 of the polycrystalline silicon rod 10 and the supply speed V P It is also mainly related to the volume of the polycrystalline silicon rod 10 to be melted. Therefore, by introducing the correlation coefficient between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP, the expression of the change in the zone melting voltage P ΔP is obtained. The change in the zone melting voltage P ΔP satisfies And adjust the settings according to this value.
[0080] In some embodiments, the correlation coefficient K2 between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP ranges from 0 to 10. Specifically, the correlation coefficient K2 between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP can be any one of 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range consisting of any two values.
[0081] It can be understood that by controlling the range of the correlation coefficient K2 between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP within 0 to 10, the zone melting voltage P can be corrected.
[0082] In some embodiments, the correction coefficient K1 of the growth time ranges from 0 to 3. Specifically, the correction coefficient K1 of the growth time can be any one of 0.1, 0.5, 1, 1.5, 2, 2.5, and 3, or a range consisting of any two values.
[0083] It can be understood that by controlling the correction coefficient K1 of the growth time within the range of 0.8 to 1.2, the supply speed V P Make corrections.
[0084] In some implementations, the time period T ranges from 0.2 to 300 seconds. Specifically, the time period T may be any one of 0.2 seconds, 10 seconds, 50 seconds, 100 seconds, 150 seconds, 200 seconds, 250 seconds, and 300 seconds, or a range consisting of any two of the values.
[0085] It can be understood that the smaller the value of the time period T is set, the higher the accuracy of the correction is, so different time periods T can be selected for different situations.
[0086] In some embodiments, the polycrystalline silicon rod 10 has a first rotation speed R P , the first speed R P The range of the first speed R is 0 to 1 r / min. p It can be any one of 0 r / min, 0.1 r / min, 0.5 r / min, 1 r / min, or a range consisting of any two values.
[0087] It is understandable that in order to ensure uniform zone melting of the polycrystalline silicon rod 10, the polycrystalline silicon rod 10 can be rotated at a first rotation speed R P Rotation. In the actual process, the rotation speed R of the polycrystalline rod P It is related to the diameter of the polycrystalline silicon rod 10 and the like.
[0088] In some embodiments, the single crystal silicon 30 has a second rotation speed R S , the second speed R S The range of the second speed R is 1 to 20 r / min. S It can be any one of 1 r / min, 5 r / min, 10 r / min, 15 r / min, 20 r / min, or a range consisting of any two values.
[0089] It is understandable that, during the growth process of the single crystal silicon 30, in order to ensure that the single crystal silicon 30 is heated evenly, the single crystal silicon 30 can be grown at the second rotation speed R S Rotation. In the actual process, the rotation speed of single crystal silicon is R S Related to the target single crystal equal diameter, etc.
[0090] The crystal pulling growth control method provided in the present application makes the supply speed V of the polycrystalline silicon rod 10 smaller than 100 during the growth process of the single crystal silicon 30. P and the melting zone voltage P and the growth rate V of the single crystal silicon 30 S By adjusting according to the corresponding relationship, the actual growth shape of the single crystal silicon 30 is made close to the standard shape of the single crystal silicon 30, that is, the crystal pulling growth control method provided in the present application, the actual shape of the grown single crystal silicon 30 can be corrected and adjusted according to known standards to make the shape tend to be consistent with the standard, which can increase the growth rate of the single crystal silicon 30 and improve the product yield of the single crystal silicon 30.
[0091] The present application will be described below by taking the growth of a single crystal silicon 30 having a uniform diameter of 8 inches as an example.
[0092] Providing a polycrystalline silicon rod 10, the diameter D0 of the polycrystalline silicon rod 10, D0 = 160 mm;
[0093] During the growth of the single crystal silicon 30, the supply speed V of the polycrystalline silicon rod 10 is set to P and the melting zone voltage P and the growth rate V of the single crystal silicon 30 S According to the corresponding relationship, the supply speed V of the polysilicon rod 10 is adjusted. P satisfy The zone melting voltage P satisfies Growth rate V of single crystal silicon 30 S satisfy
[0094]
[0095] During several time periods T of growth of the single crystal silicon 30 , the above adjustment steps are repeated, and the single crystal silicon growth parameters in each time period T are shown in Table 1.
[0096] Table 1
[0097]
[0098]
[0099] According to Table 1, the crystal pulling growth control method provided by the present application continuously updates and iterates the monitoring cycle during the growth of the silicon single crystal, continuously inputs the monitoring value to participate in the calculation in each cycle, continuously corrects the value, realizes automatic parameter control, and realizes automatic crystal growth. P and the melting zone voltage P and the growth rate V of single crystal silicon SBy adjusting according to the corresponding relationship, the actual growth shape of the single crystal silicon is made close to the standard shape of the single crystal silicon, which can increase the growth rate of the single crystal silicon and improve the product yield of the single crystal silicon.
[0100] The above is a detailed introduction to the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.
Claims
1. A method for controlling crystal growth, characterized in that: include: Set the melting zone voltage P and supply speed V of the polysilicon rod P , so that the polycrystalline silicon rods are zone melted to form single crystal silicon; Obtaining a single crystal silicon diameter d and a single crystal silicon cone height h of the single crystal silicon in each time period T; According to the diameter d of the single crystal silicon, a theoretical crystal cone height h0 is obtained; Subtract the height h of the single crystal silicon cone from the theoretical crystal cone height h0 to obtain a deviation Δh; According to the deviation Δh, the supply speed V is adjusted. P and the zone melting voltage P to achieve the single crystal silicon growth.
2. The crystal pulling growth control method according to claim 1, characterized in that: The step of obtaining the theoretical crystal cone height h0 according to the single crystal silicon diameter d comprises: According to the diameter d of the single crystal silicon, the growth rate V of the single crystal silicon is obtained. S ; According to the growth rate V of the single crystal silicon S , obtain the crystal theoretical cone height h0.
3. The crystal pulling growth control method according to claim 2, characterized in that: According to the diameter d of the single crystal silicon, the growth rate V of the single crystal silicon is obtained. S The steps include: A first theoretical function is established, wherein the expression of the first theoretical function is: Where d0 represents the theoretical equivalent diameter of the crystal, d1 represents the standard diameter of the crystal, and V S1 represents the standard growth rate of the first crystal, D represents the standard equal diameter of the crystal, V SD represents the standard growth rate of the second crystal, and H represents the standard cone height of the crystal; Let d0 = d, and obtain the corresponding growth rate V of the single crystal silicon through the first theoretical function. S0 , the growth rate V S =V S0 .
4. The crystal pulling growth control method according to claim 3, characterized in that: According to the growth rate V of the single crystal silicon S , the steps of obtaining the crystal theoretical cone height h0 include: A second theoretical function is established, and the expression of the second theoretical function is: Let V S0 =V S And through the second theoretical function, the crystal theoretical cone height h0 is obtained.
5. The crystal pulling growth control method according to claim 1, characterized in that: The polycrystalline silicon rod has a polycrystalline silicon rod diameter D0. In the process of melting the polycrystalline silicon rod to form single crystal silicon, the volume of the melted polycrystalline silicon rod and the volume of the formed single crystal silicon satisfy: Among them, V S represents the growth rate of single crystal silicon, K1 represents the correction coefficient of the growth time of single crystal silicon, and t represents the growth time of single crystal silicon.
6. The crystal pulling growth control method according to claim 5, characterized in that: The supply speed V P Satisfaction: V P =V P1 +ΔV P2 , where V P1 Indicates the supply speed V P The first correction value, ΔV P2 Indicates the supply speed V P The second correction value.
7. The crystal pulling growth control method according to claim 6, characterized in that: The first correction value V P1 satisfy:
8. The crystal pulling growth control method according to claim 6, characterized in that: According to the deviation Δh, the supply speed V is obtained. P The second correction value ΔV P2 , The second correction value ΔV P2 satisfy: Among them, K p Represents proportional gain; T t represents the integral time constant; T D represents the differential time constant.
9. The crystal pulling growth control method according to claim 5, characterized in that: The zone melting voltage P satisfies: n =P n-1 +ΔP, where n is an integer greater than or equal to 2, P n is the zone melting voltage of the polysilicon rod at the nth time period T, P n-1 is the zone melting voltage of the polysilicon rod in the n-1th time period T, and ΔP is the change of the zone melting voltage P between two adjacent time periods.
10. The crystal pulling growth control method according to claim 9, characterized in that: The variation ΔP of the zone melting voltage P satisfies: Wherein, K2 represents the correlation coefficient between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP.
11. The crystal pulling growth control method according to claim 10, characterized in that: The correlation coefficient K2 between the change in the volume of the polycrystalline silicon rod and the change in the zone melting voltage P ΔP ranges from 0 to 10.
12. The crystal pulling growth control method according to claim 5, characterized in that: The correction coefficient K1 of the growth time ranges from 0 to 3.
13. The crystal pulling growth control method according to claim 1, characterized in that: The time period T ranges from 0.2 to 300 seconds.