Control method, device and readable medium for automatic shoulder release of heavily doped single crystal

Abstract

The present invention provides a control method, device and readable medium for automatic shouldering of a heavily doped single crystal, belonging to the field of electrical control technology for crystal pulling. The pulling speed is feedback-adjusted through the actual diameter collected in real time, and power intervention is performed so that the shouldering process is performed in accordance with a predetermined longitudinal growth first, then stable growth, and finally lateral growth. Thus, the control accuracy of the pulling speed is improved during the heavily doped shouldering process, and temperature compensation is appropriately performed through power, so that the stability during the shouldering process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal pulling electrical control, and in particular to a control method, device and readable medium for automatic shouldering of a heavily doped single crystal. Background Art

[0002] Single crystal manufacturing is the process of melting silicon material and then using the Czochralski technique to convert polycrystalline into dislocation-free single crystals. However, during the process of converting polycrystalline into single crystals, dislocations may occur for some reason, and the crystal will lose its single crystal properties and turn into polycrystalline. At this time, crystal growth fails (called NG).

[0003] When the impurity concentration is higher or the furnace pressure and argon gas are higher, the probability of the seeding shoulder not being able to survive is getting higher and higher. More than 60% of the NG positions are concentrated in the shoulder release stage. How to reduce the number of shoulder release NGs under the increasingly higher impurity concentration and increasingly stringent process conditions is an urgent problem to be solved. In the prior art, such as the authorization announcement No. CN114717648B discloses a method for improving <100> The shoulder releasing method for improving the survival rate of single crystal uses a steep shoulder for pulling and fixes a shoulder releasing angle before shoulder releasing. Although this method can effectively reduce the number of shoulder releasing NGs, it has poor stability in the face of increasingly high impurity concentrations and increasingly stringent process conditions. It requires a lot of manpower to track and adjust the shoulder releasing process. Such a process adjustment mode cannot cope with large-scale production. Summary of the invention

[0004] In view of this, the present invention provides a control method, device and readable medium for automatic shoulder release of heavily-doped single crystals with high stability and adaptability to large-scale production.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for controlling automatic shoulder release of a heavily doped single crystal comprises the following steps:

[0007] S1: Obtain the angle setting value of the shoulder angle at different shoulder heights;

[0008] S2: according to the obtained shoulder angle setting values ​​of different shoulder heights, the corresponding shoulder diameter setting values ​​under different shoulder heights are obtained by a predetermined calculation formula;

[0009] S3: collect the actual diameter in the shoulder release process in real time according to the shoulder release height;

[0010] S4: Compare the actual diameter collected in real time with the diameter setting value to obtain a diameter difference Δd;

[0011] S5: taking the diameter difference Δd as the input of PID control to obtain the casting speed adjustment value and the power intervention operation amount output by PID;

[0012] S6: adjusting the real-time pulling speed according to the pulling speed adjustment value and the power intervention operation amount output by the PID, and performing power intervention to obtain a symmetrical stepped shoulder shape.

[0013] Preferably, the predetermined calculation formula is: D=2Htan(α / 2)

[0014] Where: D is the setting value of the shoulder diameter, H is the shoulder height, and α is the setting value of the shoulder angle.

[0015] Preferably, the step S5 includes: taking the diameter difference Δd as an input of PID control, and outputting a corresponding pulling speed adjustment value and a power intervention operation amount according to a first predetermined judgment formula and a second predetermined judgment formula.

[0016] Preferably, the first judgment formula is: when 0mm<Δd≤3mm, the pulling speed increases by 0.1mm / min-0.2mm / min, and when 3mm<Δd, the pulling speed increases by 0.3mm / min;

[0017] When -3mm≤Δd<0mm, the pulling speed is reduced by 0.1mm / min-0.2mm / min; when Δd<-3mm, the pulling speed is reduced by 0.3mm / min.

[0018] Preferably, the second judgment formula is:

[0019] Δd≤1mm, no first power intervention;

[0020] 1mm<Δd, power operation amount is reduced by 0.2kw.

[0021] Preferably, the reaction period of the casting speed adjustment value according to the change of the diameter difference Δd is less than 1 minute.

[0022] Preferably, the reaction period of the power intervention according to the change in the diameter difference Δd is less than 5 minutes.

[0023] A control device for automatic shoulder release of heavily doped single crystal, comprising:

[0024] Acquisition module: used to obtain the angle setting value of the shoulder angle at different shoulder heights;

[0025] Calculation module: used for calculating the corresponding shoulder diameter setting values ​​at different shoulder heights according to the angle setting values ​​of the shoulder type angles at different shoulder heights obtained by the acquisition module;

[0026] Collection module: used to collect the actual diameter of different shoulder heights in real time.

[0027] Comparison module: used for comparing the actual diameter at the same shoulder height collected by the collection module with the diameter setting value calculated by the calculation module to obtain the diameter difference Δd;

[0028] PID control module: used to use the diameter difference Δd obtained by the comparison module as the input of the PID control module, and obtain the adjustment value of the pulling speed or the power intervention operation amount through the PID algorithm.

[0029] Adjustment module: used to adjust the real-time pulling speed according to the pulling speed adjustment value output by the PID control module to obtain the actual pulling speed;

[0030] Used to perform power intervention according to the power intervention operation amount output by the PID control module.

[0031] A computing device comprising: at least one memory and at least one processor;

[0032] The at least one memory is used to store a machine-readable program;

[0033] The at least one processor is used to call the machine-readable program to execute any one of the above methods for controlling automatic shoulder release of a heavily-doped single crystal.

[0034] A computer-readable medium stores computer instructions, which, when executed by a processor, cause the processor to execute any of the above methods for controlling automatic shouldering of a heavily-doped single crystal.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention feedback-adjusts the pulling speed through the actual diameter collected in real time, and performs power intervention, so that the shouldering process is carried out in accordance with the predetermined longitudinal growth first, then stable growth, and finally lateral growth, and temperature compensation is appropriately performed through power, so that the control accuracy of the pulling speed in the heavy-doping shouldering process is improved, and then the stability in the shouldering process is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a graph of the target pulling speed curve, the target pulling speed upper limit curve, and the target pulling speed lower limit curve of the first embodiment.

[0038] Figure 2 It is the predetermined shoulder power curve.

[0039] Figure 3 It is a shoulder-type diagram of embodiment one.

[0040] Figure 4 It is a shoulder-to-shoulder type diagram in proportion.

[0041] Figure 5 Comparison chart of average shoulder release times between Example 1 and Comparative Example 1.

[0042] Figure 6 Illustration of the control device for automatic shoulder placement of heavily doped single crystals.

[0043] Figure 7 A diagram of a computing device.

[0044] Among them: a control device 10 for automatic shoulder release of heavily-doped single crystal, an acquisition module 100, a calculation module 200, a collection module 300, a comparison module 400, a PID control module 500, an adjustment module 600, a pulling speed adjustment unit 610, and a power intervention unit 620.

[0045] Computing device 20 , memory 21 , processor 22 . DETAILED DESCRIPTION

[0046] The technical scheme and technical effects of the present invention are further elaborated in detail below in conjunction with the accompanying drawings of the present invention.

[0047] A method for controlling automatic shoulder release of a heavily doped single crystal comprises the following steps:

[0048] S1: Obtain the angle setting value of the shoulder angle at different shoulder heights;

[0049] S2: according to the obtained shoulder angle setting values ​​of different shoulder heights, the corresponding shoulder diameter setting values ​​under different shoulder heights are obtained by a predetermined calculation formula;

[0050] S3: collect the actual diameter in the shoulder release process in real time according to the shoulder release height;

[0051] S4: Compare the actual diameter collected in real time with the diameter setting value to obtain a diameter difference Δd; the diameter difference Δd at the same shoulder height = actual diameter - diameter setting value;

[0052] S5: taking the diameter difference Δd as the input of PID control to obtain the casting speed adjustment value and the power intervention operation amount output by PID;

[0053] S6: According to the pulling speed adjustment value and the power intervention operation amount output by the PID, the real-time pulling speed is adjusted accordingly, and power intervention is performed to adjust the temperature and pulling speed in time to prevent the loss of the crystal structure during the shoulder release process, thereby obtaining a symmetrical stepped shoulder shape.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The present invention feedback-adjusts the pulling speed through the actual diameter collected in real time, and performs power intervention, so that the shouldering process is carried out in accordance with the predetermined longitudinal growth first, then stable growth, and finally lateral growth, and temperature compensation is appropriately performed through power, so that the control accuracy of the pulling speed in the heavy-doping shouldering process is improved, and then the stability in the shouldering process is improved.

[0056] Furthermore, the predetermined calculation formula is: D=2Htan(α / 2)

[0057] Where: D is the setting value of the shoulder diameter, H is the shoulder height, and α is the setting value of the shoulder angle.

[0058] Furthermore, the step S5 includes: using the diameter difference Δd as an input of PID control, and according to the first predetermined judgment formula and the second predetermined judgment formula, PID outputs the corresponding pulling speed adjustment value and power intervention operation amount.

[0059] Furthermore, the first judgment formula is: when 0mm<Δd≤3mm, the pulling speed increases by 0.1mm / min-0.2mm / min, and when 3mm<Δd, the pulling speed increases by 0.3mm / min;

[0060] When -3mm≤Δd<0mm, the pulling speed is reduced by 0.1mm / min-0.2mm / min; when Δd<-3mm, the pulling speed is reduced by 0.3mm / min.

[0061] Further, the first judgment formula is: when 0mm<Δd≤1mm, the pulling speed increases by 0.1mm / min, when 1mm<Δd≤3mm, the pulling speed increases by 0.2mm / min, and when 3mm<Δd, the pulling speed increases by 0.3mm / min;

[0062] When -1mm≤Δd<0mm, the pulling speed is reduced by 0.1mm / min; when -3mm≤Δd<1mm, the pulling speed is reduced by 0.2mm / min; when Δd<-3mm, the pulling speed is reduced by 0.3mm / min.

[0063] Furthermore, the second judgment formula is:

[0064] Δd≤1mm, no first power intervention;

[0065] 1mm<Δd, power operation amount is reduced by 0.2kw.

[0066] Furthermore, the reaction period of the casting speed adjustment value according to the change of the diameter difference Δd is less than 1 minute.

[0067] Furthermore, the reaction period of the power intervention according to the change of the diameter difference Δd is less than 5 minutes.

[0068] Please see Figure 6 , a heavily doped single crystal automatic shoulder control device 10, comprising:

[0069] Acquisition module 100: used to acquire the angle setting value of the shoulder angle at different shoulder heights;

[0070] Calculation module 200: used for calculating the corresponding shoulder diameter setting values ​​at different shoulder heights according to the shoulder angle setting values ​​at different shoulder heights obtained by acquisition module 100;

[0071] Collection module 300: used to collect the actual diameters of different shoulder heights in real time,

[0072] Comparison module 400: used to compare the actual diameter at the same shoulder height collected by the collection module 300 with the diameter setting value calculated by the calculation module 200 to obtain a diameter difference Δd;

[0073] PID control module 500: used to use the diameter difference Δd obtained by the comparison module 400 as the input of the PID control module 500, and obtain the adjustment value of the casting speed or the power intervention operation amount through the PID algorithm.

[0074] The regulating module 600 is used to adjust the real-time pulling speed according to the pulling speed regulating value output by the PID control module 500 to obtain the actual pulling speed; and to perform power intervention according to the power intervention operation amount output by the PID control module 500.

[0075] Furthermore, the regulating module 600 includes a pulling speed regulating unit 610 and a power intervention unit 620;

[0076] The pulling speed adjustment unit 610 is used to adjust the real-time pulling speed according to the pulling speed adjustment value output by the PID control module 500 to obtain the actual pulling speed;

[0077] The power intervention unit 620 is used to perform power intervention according to the power intervention operation amount output by the PID control module 500.

[0078] Please see Figure 7 , a computing device 20, comprising: at least one memory 21 and at least one processor 22;

[0079] The at least one memory 21 is used to store a machine-readable program;

[0080] The at least one processor 22 is coupled to the at least one memory 21, and is used to call the machine-readable program to execute the method for controlling the quality of heavily-doped single crystal seeding as described in any one of the above embodiments.

[0081] A computer-readable medium having computer instructions stored thereon, wherein when the computer instructions are executed by a processor, the processor is caused to execute the method for controlling the quality of heavily-doped single crystal seeding as described in any one of the above embodiments. Specifically, a system or device equipped with a storage medium may be provided, wherein the storage medium stores software program codes for implementing the functions of any one of the above embodiments, and a computer (or CPU or MPU) of the system or device is caused to read and execute the program codes stored in the storage medium.

[0082] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0083] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer via a communication network.

[0084] Specifically, the present invention is described by the following examples and comparative examples.

[0085] The following embodiments and comparative examples are based on single crystals drawn to 8 inches, with a resistivity of less than 0.002Ω·cm, a doping ratio of >8 times the feed amount, and a furnace pressure of >33Kpa. Embodiment 1:

[0086] Through PID control, in the system (FT-CZ2408S2-3212SE-PCE-Ver4.209), the shoulder angles of different shoulder heights are obtained as follows: the shoulder height is 0mm to 80mm, the shoulder angle is 35°~40°, the shoulder height is 85mm to 210mm, the shoulder angle is 40°~45°, the shoulder height is 215mm to 280mm, and the shoulder angle is 45°~55°. Figure 1 The target pulling speed curve, the target pulling speed upper limit curve, the target pulling speed lower limit curve and the like Figure 2 The shoulder is released according to the preset shoulder release power curve shown in the figure. During the shoulder release process, the pulling speed is adjusted and the power intervention compensation is performed according to the diameter difference Δd between the instantaneous diameter and the diameter setting value. Figure 1 As described above, the shoulders are automatically released according to the control method; the shoulder shape obtained by releasing the shoulders is as follows Figure 3 shown.

[0087] Comparative Example 1

[0088] For example, the authorization announcement number CN114717648B discloses a method for improving <100> In the specific implementation method of the single crystal survival rate shoulder release method, the scheme in embodiment 1 is performed, and the shoulder release shoulder type is as follows Figure 4 As shown, the parameters not mentioned are the same as those in the first embodiment.

[0089] According to the scheme of Example 1 and Comparative Example 1, the experiment was carried out for a period of one month, and the number of shoulder releases obtained was as follows: Figure 5 shown.

[0090] Depend on Figure 3 , Figure 4 It can be seen that when the heavy doping concentration is high and the furnace pressure is high, the shoulder diameter of Example 1 can be stably controlled within ±0.5mm (the difference between the actual shoulder diameter and the set diameter), and the shoulder diameter difference of Comparative Example 1 can be controlled within ±4mm. The shoulder diameter difference of the present invention is greatly reduced compared with Comparative Example 1, so that the stability of the drawing process is greatly improved. Through the control method of the present invention, the difference between the shoulder shape obtained by drawing and the target shoulder shape is small, and thus the stability is high; and from Figure 5 It can also be seen that the control stability of the present invention is high and the NG ratio is significantly lower than that of the comparative example 1. Therefore, the application range of the present invention is wide, and it is more conducive to large-size crystallization with high heavy doping concentration, and it has strong control effect and high stability.

[0091] While for comparative example 1, when the doping ratio is suitable for 6.5-7.0 times of the feed amount and the pressure in the furnace is in the range of <26Kpa, the drawing stability is high and the NG rate is low.

[0092] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for controlling automatic shoulder release of heavily doped single crystal, characterized in that: The following steps are involved: S1: Obtaining the angle setting values ​​of the shoulder angles of different shoulder heights; the shoulder height is 0mm to 80mm, and the shoulder angle is 35°~40°; the shoulder height is 85mm to 210mm, and the shoulder angle is 40°~45°; the shoulder height is 215mm to 280mm, and the shoulder angle is 45°~55°; S2: according to the obtained shoulder angle setting values ​​of different shoulder heights, the corresponding shoulder diameter setting values ​​under different shoulder heights are obtained by a predetermined calculation formula; S3: collect the actual diameter in the shoulder release process in real time according to the shoulder release height; S4: Compare the actual diameter collected in real time with the diameter setting value to obtain a diameter difference Δd; S5: taking the diameter difference Δd as the input of PID control to obtain the casting speed adjustment value and the power intervention operation amount output by PID; The step S5 includes: taking the diameter difference Δd as the input of PID control, and outputting the corresponding pulling speed adjustment value and power intervention operation amount according to the first predetermined judgment formula and the second predetermined judgment formula; The first judgment formula is: when 0mm<Δd≤3mm, the pulling speed increases by 0.1mm / min-0.2mm / min, and when 3mm<Δd, the pulling speed increases by 0.3mm / min; When -3mm≤Δd<0mm, the pulling speed is reduced by 0.1mm / min-0.2mm / min, and when Δd<-3mm, the pulling speed is reduced by 0.3mm / min; The second judgment formula is: Δd≤1mm, and the first power intervention is not performed; 1mm<Δd, power operation amount is reduced by 0.2kw; S6: adjusting the real-time pulling speed according to the pulling speed adjustment value and the power intervention operation amount output by the PID, and performing power intervention to obtain a symmetrical stepped shoulder shape.

2. The method for controlling automatic shoulder release of heavily doped single crystal according to claim 1, characterized in that: The predetermined calculation formula is: D=2Htan(α / 2) Where: D is the setting value of the shoulder diameter, H is the shoulder height, and α is the setting value of the shoulder angle.

3. The control method for automatic shoulder release of heavily doped single crystal according to claim 1, characterized in that: The reaction period of the pulling speed adjustment value according to the change of the diameter difference Δd is less than 1 minute.

4. The method for controlling automatic shoulder release of heavily doped single crystal according to claim 1, characterized in that: The reaction period of the power intervention according to the change of the diameter difference Δd is less than 5 minutes.

5. A control device for automatic shoulder release of heavily doped single crystal, characterized in that: include: Acquisition module: Acquisition of the angle setting values ​​of the shoulder angle at different shoulder heights; wherein, when the shoulder height is 0mm to 80mm, the shoulder angle is 35°~40°; when the shoulder height is 85mm to 210mm, the shoulder angle is 40°~45°; when the shoulder height is 215mm to 280mm, the shoulder angle is 45°~55°; Calculation module: according to the obtained angle setting values ​​of the shoulder type angles of different shoulder release heights, the corresponding shoulder release diameter setting values ​​under different shoulder release heights are obtained through a predetermined calculation formula; Collection module: collects the actual diameter in the shoulder release process in real time according to the shoulder release height; Comparison module: compares the actual diameter collected in real time with the diameter setting value to obtain a diameter difference Δd; PID control module: taking the diameter difference Δd as the input of PID control, obtaining the pulling speed adjustment value and the power intervention operation amount output by PID; wherein, taking the diameter difference Δd as the input of PID control, according to the first predetermined judgment formula and the second predetermined judgment formula, the pulling speed adjustment value and the power intervention operation amount corresponding to the PID output are obtained; Among them, the first judgment formula is: when 0mm<Δd≤3mm, the pulling speed increases by 0.1mm / min-0.2mm / min, and when 3mm<Δd, the pulling speed increases by 0.3mm / min; When -3mm≤Δd<0mm, the pulling speed is reduced by 0.1mm / min-0.2mm / min, and when Δd<-3mm, the pulling speed is reduced by 0.3mm / min; The second judgment formula is: Δd≤1mm, the first power intervention is not performed; 1mm<Δd, power operation amount is reduced by 0.2kw; Adjustment module: adjust the real-time pulling speed according to the pulling speed adjustment value and power intervention operation amount output by the PID, and perform power intervention to obtain a symmetrical stepped shoulder shape.

6. A computing device comprising: at least one memory and at least one processor; The at least one memory is used to store a machine-readable program; The at least one processor is used to call the machine-readable program to execute the control method for automatic shoulder release of the heavily-doped single crystal as described in any one of claims 1 to 4.

7. A computer-readable medium having computer instructions stored thereon, wherein when the computer instructions are executed by a processor, the processor is caused to execute the method for controlling automatic shoulder release of a heavily-doped single crystal as claimed in any one of claims 1 to 4.

Images