Single crystal growth method, control device, and single crystal growth device
By compensating the lifting speed according to the position deviation of the crucible during the single crystal growth process, the single crystal defect problem caused by temperature gradient instability is solved, and the quality of the single crystal is improved.
Patent Information
- Application Number
- CN202411519832.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-02-07
AI Technical Summary
In the existing direct-pullization single crystal growth method, the instability of the temperature gradient leads to many defects in the single crystal, affecting the quality of the crystal.
By placing silicon material in the crucible of the crystal furnace and using the processor and memory control device, the pulling speed is compensated according to the deviation value of the actual position of the crucible and the target position, ensuring the stability of the ratio of the pulling speed to the temperature gradient.
By controlling the ratio of pulling speed to temperature gradient, the defects of single crystals are reduced and the quality and quality of single crystals are improved.
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Figure CN119392352A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a single crystal growth method, a control device and a single crystal growth device. Background Art
[0002] The Czochralski method is a commonly used single crystal growth method. In this method, polycrystalline silicon in a high-purity quartz crucible is melted in a straight cylindrical furnace using graphite resistance heating. A seed crystal is then inserted into the melt surface for welding while the seed crystal is rotated. The crucible is then reversed and the seed crystal is slowly lifted upward. After the processes of seeding, shoulder release, shoulder rotation, equal diameter growth, and finishing, it eventually grows into a crystal rod of the required diameter and length.
[0003] In the isodiametric stage, the pulling speed (V) and the temperature gradient (G) are important parameters that affect defects. According to Voronkov's V / G theory, more point defects are likely to occur when the V / G value is large or small: when the V / G value is large, too many point defects will be vacancies, which are the source of octahedral hole defects (D-defect for short); when the V / G value is small, the point defects are mainly self-interstitial atoms, which are the source of dislocation rings (A-swirl for short) and clusters (B-swirl for short).
[0004] With the development of semiconductors, the quality requirements of single crystals are getting higher and higher. In order to obtain defect-free single crystals, the V / G value needs to be controlled in a very small range. V can be precisely controlled by equipment, but G will be affected by many factors. One of the most important influences is the relative position of the graphite crucible and the heater at the same equal diameter length. The shoulder shape, quartz crucible size, crystal pulling diameter, etc. will cause the relative position of the graphite crucible and the heater to be different at the same equal diameter length, which will cause G to change, resulting in more defects in the single crystal and a decrease in the quality of the crystal pulling.
[0005] Therefore, it is necessary to propose a single crystal growth method to solve the problems in the prior art. Summary of the invention
[0006] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.
[0007] In view of the existing problems, the present application provides a single crystal growth method, including:
[0008] Placing silicon material in a crucible of a crystal growth furnace;
[0009] heating the crucible to melt the silicon material into a silicon melt;
[0010] The seed crystal is immersed in the silicon melt, and the seed crystal is rotated and pulled upward at a current pulling speed, so that the silicon melt solidifies and crystallizes at the lower end of the seed crystal to obtain a single crystal silicon crystal rod; wherein the preset pulling speed is compensated by the deviation value between the current actual position of the crucible and the current target position to obtain the current pulling speed to control the ratio of the current pulling speed of the crucible to the temperature gradient.
[0011] In some embodiments, compensating the preset pulling speed by the deviation value between the current actual position of the crucible and the current target position includes:
[0012] In the isodiameter growth stage, based on the current isodiameter length, a corresponding first proportional coefficient is obtained from a pre-obtained proportional relationship curve between the crucible rising distance and the isodiameter length;
[0013] Obtaining a compensation value of a preset pulling speed of the crucible according to the deviation value and the first proportional coefficient;
[0014] The preset pulling speed is compensated based on the compensation value to obtain a current pulling speed of the crucible.
[0015] In some embodiments, before compensating the preset pulling speed by the deviation value between the current actual position of the crucible and the current target position, the method further includes:
[0016] Obtaining a pre-generated corresponding relationship curve between the crucible rising distance and the equal diameter length;
[0017] Based on the current equal diameter length, the current target position of the crucible is obtained from the corresponding relationship curve.
[0018] In some embodiments, before obtaining the pre-generated corresponding relationship curve between the crucible rising distance and the equal diameter length, the method further includes:
[0019] Calculate the target lifting distance of the crucible according to the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible;
[0020] The corresponding relationship curve is generated according to the crucible target rising distance when the target diameter length is different.
[0021] In some embodiments, it also includes:
[0022] Calculate the target lifting distance of the crucible according to the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible;
[0023] According to the crucible target rising distance and the target equal diameter length, obtaining a ratio of the crucible target rising distance to the target equal diameter length;
[0024] The proportional relationship curve is generated according to the ratio of the crucible target rising distance to the target equal diameter length at different target equal diameter lengths.
[0025] In some embodiments, the target lifting distance of the crucible is calculated based on the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible, including:
[0026] Obtaining a target weight of the single crystal silicon according to the target shoulder weight, the target equal-diameter diameter and the target equal-diameter length;
[0027] The target lifting distance of the crucible is obtained according to the target weight of the silicon single crystal and the actual size of the crucible.
[0028] In some embodiments, placing silicon material in a crucible of a crystal growth furnace comprises:
[0029] Putting silicon material into the crucible;
[0030] The crystal growth furnace is closed and evacuated, and a protective gas is filled into the crystal growth furnace, wherein the protective gas includes argon.
[0031] In some embodiments, when the crucible is heated, the heating temperature is greater than or equal to 1420°C.
[0032] A second aspect of an embodiment of the present application provides a control device, including: a processor and a memory;
[0033] The memory is used to store computer programs;
[0034] The processor is used to execute the computer program stored in the memory so as to enable the control device to perform the single crystal growth method as described above.
[0035] A third aspect of the present application provides a single crystal growth device, including:
[0036] A crystal growth furnace is used to melt silicon material and solidify and crystallize it to obtain a single crystal silicon ingot;
[0037] A control device is used to control the pulling speed of the seed crystal during the growth of the single crystal silicon according to the single crystal growth method as described above.
[0038] The single crystal growth method provided in the present application compensates for the preset pulling speed by the deviation value between the current actual position of the crucible and the current target position, controls the current pulling speed and temperature gradient ratio of the crucible to remain unchanged, reduces single crystal defects, and improves single crystal quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.
[0040] In the attached figure:
[0041] Figure 1 A schematic diagram showing the structure of a crystal growth furnace used in a single crystal growth method according to an embodiment of the present application is shown;
[0042] Figure 2 A schematic diagram showing a process of a single crystal growth method according to an embodiment of the present application is shown;
[0043] Figure 3 A graph showing the relationship between the rising distance of a crucible and the equal diameter length according to an embodiment of the present application is shown;
[0044] Figure 4 A graph showing the current position and target position of the crucible in the equal diameter stage according to one embodiment of the present application;
[0045] Figure 5 A crucible position difference curve diagram of an equal diameter stage according to an embodiment of the present application is shown;
[0046] Figure 6 A schematic diagram showing the structure of a control device according to an embodiment of the present application is shown;
[0047] Figure 7 A schematic structural diagram of a single crystal growth device according to an embodiment of the present application is shown. DETAILED DESCRIPTION
[0048] Next, the present application will be described more completely in conjunction with the accompanying drawings, in which embodiments of the present application are shown. However, the present application can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, for clarity, the sizes and relative sizes of layers and regions may be exaggerated. The same reference numerals throughout represent the same elements.
[0049] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.
[0050] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.
[0051] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "a", "an", and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.
[0052] Embodiments of the invention are described herein with reference to cross-sectional views that are schematic diagrams of ideal embodiments (and intermediate structures) of the present application. Thus, variations from the shapes shown due to, for example, manufacturing techniques and / or tolerances can be expected. Therefore, embodiments of the present application should not be limited to the specific shapes of the zones shown herein, but include shape deviations due to, for example, manufacturing. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges, rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the actual shape of the region of the device and are not intended to limit the scope of the present application.
[0053] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by ordinary technicians in the field of this application. It will also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an ideal or overly formal sense unless expressly defined as such herein.
[0054] At present, the preparation method of single crystal silicon ingot is mainly the Czochralski method, and its main process steps include seeding, shouldering, equal diameter, and finishing. Voronkov's V / G theory reveals the dynamics of crystal growth and defects. However, the shoulder shape, quartz crucible size, crystal pulling diameter, etc. will lead to different relative positions of graphite crucible and heater at the same equal diameter length, which will cause G to change, resulting in more defects in the single crystal and reduce the quality of crystal pulling.
[0055] In response to the above problems, the present application provides a single crystal growth method, a control device and a single crystal growth device, which can improve the quality of single crystals, and are described in detail below.
[0056] In order to thoroughly understand the present application, detailed structures and / or steps will be presented in the following description to illustrate the technical solution proposed by the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.
[0057] The following will refer to Figures 1 to 3 , the growth method of silicon single crystals in some embodiments of the present application is described in detail.
[0058] first, Figure 1 A schematic diagram of a crystal growth furnace used in the single crystal growth method provided in the embodiment of the present application is shown. Figure 1As shown, the crystal growth furnace is used to grow silicon single crystals by the Czochralski method, and includes a furnace body 101, in which a heating device and a pulling device are provided. The heating device includes a quartz crucible 102, a graphite crucible 103, and a heater 104. Among them, the quartz crucible 102 is used to hold silicon materials, such as polycrystalline silicon. The silicon materials are heated therein to become silicon melt 105. The graphite crucible 103 is wrapped around the outside of the quartz crucible 102, and is used to provide support for the quartz crucible 102 during the heating process. The heater 104 is arranged on the outside of the graphite crucible 103. A heat shield is arranged above the quartz crucible 102, and the heat shield includes a guide tube 106. The guide tube 106 has an inverted cone-shaped screen-shaped object extending downward and surrounding the growth area of the silicon single crystal 107, which can block the direct heat radiation of the heater 104 and the high-temperature silicon melt 105 to the growing single crystal silicon ingot 107, and reduce the temperature of the single crystal silicon ingot 107. At the same time, the heat shield can also make the downward blowing protective gas spray directly near the growth interface, further enhancing the heat dissipation of the single crystal silicon ingot 107. The side wall of the furnace body 101 is also provided with a heat-insulating material, such as carbon felt.
[0059] The pulling device includes a vertically arranged seed crystal shaft 108 and a crucible shaft 109. The seed crystal shaft 108 is arranged above the quartz crucible 102, and the crucible shaft 109 is arranged at the bottom of the graphite crucible 103. The bottom of the seed crystal shaft 108 is equipped with a seed crystal through a clamp, and the top is connected to a seed crystal shaft driving device so that it can be slowly pulled upward while rotating. The bottom of the crucible shaft 109 is provided with a crucible shaft driving device so that the crucible shaft 109 can drive the crucible to rotate.
[0060] When growing a single crystal, firstly, silicon material is put into the quartz crucible 102 , and then the heater 104 is turned on to heat and melt the silicon material into a silicon melt 105 .
[0061] Next, the seed crystal is immersed in the silicon melt 105, and the seed crystal is driven to rotate and slowly pulled by the seed crystal axis 108, so that silicon atoms grow along the seed crystal into a single crystal silicon ingot 107. The seed crystal is cut or drilled from a silicon single crystal with a certain crystal orientation, and the seed crystal is generally a cylinder or a cuboid. The growth process of the single crystal silicon ingot 107 includes several stages, namely, seeding, shoulder release, shoulder rotation, equal diameter and finishing.
[0062] Specifically, the seeding stage is first performed. That is, when the silicon melt 105 stabilizes to a certain temperature, the seed crystal is immersed in the silicon melt, and the seed crystal is lifted at a certain pulling speed, so that the silicon atoms grow along the seed crystal into a thin neck with a certain diameter until the thin neck reaches a predetermined length. The main function of the seeding process is to eliminate the dislocation defects formed by single crystal silicon due to thermal shock, and to use the supercooling of the crystallization front to drive the silicon atoms to be arranged in order on the silicon solid at the solid-liquid interface to form single crystal silicon.
[0063] Then, it enters the shoulder release stage. When the neck reaches a predetermined length, the speed of pulling the seed crystal upward is slowed down, and the temperature of the silicon melt is slightly reduced. The cooling is performed to promote the lateral growth of the single crystal silicon, even if the diameter of the single crystal silicon increases. This process is called the shoulder release stage, and the conical crystal rod formed in this stage is the shoulder release section of the crystal rod.
[0064] Then, the shoulder turning stage is entered. When the diameter of the single crystal silicon increases to the target diameter, the heating power of the heater 104 is increased, the temperature of the silicon melt is increased, and the speed of pulling the seed crystal upward, the speed of rotation, and the rotation speed of the quartz crucible are adjusted at the same time, so as to suppress the lateral growth of the single crystal silicon and promote its longitudinal growth, so that the single crystal silicon grows with almost equal diameter, which is the shoulder release stage. During the crystal pulling process, in order to keep the liquid level position unchanged, the crucible rises at a certain speed as the internal solution decreases and changes with the crystal rise. During the shoulder turning process, there is a curved liquid surface at the junction of the crystal side wall and the melt, which becomes a meniscus. As the shoulder turning process proceeds, the width and brightness of the meniscus increase. The change in crystal diameter can be known by measuring the brightness and width of the meniscus, and the process parameters such as the crystal pulling rate can be adjusted in time to ensure the smooth progress of the shoulder turning process to achieve the expected crystal diameter.
[0065] Then, it enters the equal diameter stage. When the diameter of the single crystal silicon ingot reaches a predetermined value, it enters the equal diameter stage. The cylindrical ingot formed in this stage is the equal diameter section of the ingot. Specifically, the crucible temperature, crystal pulling speed, crucible rotation speed and crystal rotation speed are adjusted to stabilize the growth rate so that the crystal diameter remains unchanged until the crystal pulling is completed. The equal diameter process is the main stage of single crystal silicon growth, which can last for dozens of hours or even more than a hundred hours of growth.
[0066] In the present application, when semiconductor-grade single crystal silicon is produced, the seeding and shoulder release processes can be carried out according to conventional processes, while the pulling speed in the equal-diameter stage is optimized.
[0067] Based on this, refer to Figure 2 According to some embodiments of the present application, the single crystal growth method includes steps S210 to S230. Each step is described below.
[0068] In step S210 , silicon material is placed in a crucible of a crystal growth furnace.
[0069] Specifically, silicon material may be placed in the quartz crucible 102 , and then the crystal growth furnace is closed and evacuated, and a protective gas, which may be argon, is filled into the crystal growth furnace.
[0070] During the single crystal growth process, argon gas can be introduced from top to bottom onto the silicon melt, which can take away SiO above the silicon melt and cool the single crystal silicon rod, increasing its axial temperature gradient and allowing the single crystal to grow rapidly.
[0071] In step S220 , the crucible is heated to melt the silicon material into a silicon melt.
[0072] Specifically, the crucible may be heated by the heater 104 , and the heater 104 is heated to a melting temperature above 1420° C. to melt the silicon material into a silicon melt 105 .
[0073] In step S230, the seed crystal is immersed in the silicon melt, and the seed crystal is rotated and pulled upward at the current pulling speed, so that the silicon melt solidifies and crystallizes at the lower end of the seed crystal to obtain a single crystal silicon crystal rod; wherein the preset pulling speed is compensated by the deviation value between the current actual position of the crucible and the current target position to obtain the current pulling speed, so as to control the current pulling speed and temperature gradient ratio of the crucible.
[0074] In the present application, the current pulling speed and the preset pulling speed are the lifting speeds of the single crystal relative to the silicon melt liquid level. Compensating the preset pulling speed by the deviation between the current actual position of the crucible and the current target position is to compensate for the preset pulling speed in the equal-diameter growth stage. Here, the preset pulling speed is the ideal pulling speed in the existing single crystal silicon growth method, and the ideal pulling speed can have a corresponding relationship with the equal-diameter length, so the current preset pulling speed can be determined based on the current equal-diameter length.
[0075] During the entire single crystal growth process, the pulling speed of the seed crystal axis 108 (i.e., the pulling speed of the single crystal) is usually a preset fixed value. As the silicon melt solidifies and crystallizes at the lower end of the seed crystal, the liquid level of the silicon melt drops, and the pulling speed of the crystal relative to the liquid level, that is, the crystal process pulling speed, will change according to the speed of change of the liquid level position. The speed of change of the liquid level position is variable, so the pulling speed of the crystal relative to the liquid level, that is, the change of the crystal process pulling speed, will have a great impact on the growth of a perfect single crystal. The present application compensates for the preset pulling speed of the pulling speed of the seed crystal axis 108 by the deviation value between the current actual position of the crucible and the current target position, thereby controlling the current pulling speed of the crucible to remain unchanged with respect to the temperature gradient ratio, which helps to stabilize the single crystal growth conditions, thereby helping to grow high-quality single crystals.
[0076] After the equal diameter growth stage is completed, the finishing stage begins. During the finishing stage, the lifting rate is accelerated and the temperature of the silicon melt 105 is increased, so that the diameter of the crystal rod gradually decreases to form a cone. When the cone tip is small enough, it will eventually leave the liquid surface. The crystal rod that has completed the finishing is lifted to the upper furnace chamber and cooled for a period of time, and then taken out, completing a growth cycle.
[0077] The silicon single crystal growth method provided in the present application compensates for the preset pulling speed by the deviation value between the current actual position of the crucible and the current target position, controls the current pulling speed and temperature gradient ratio of the crucible to remain unchanged, reduces single crystal defects, and improves single crystal quality.
[0078] In some embodiments, the single crystal growth method comprises:
[0079] Before the single crystal is generated, the target lifting distance of the crucible is calculated according to the target shoulder weight, target equal diameter and target equal length of the single crystal silicon and the actual size of the crucible;
[0080] According to the crucible target rising distance and the target equal diameter length, a ratio of the crucible target rising distance to the target equal diameter length is obtained;
[0081] A proportional relationship curve is generated according to the ratio of the crucible target rising distance to the target equal diameter length at different target equal diameter lengths.
[0082] Figure 3 A graph showing the relationship between the crucible rise distance and the equal diameter length according to an embodiment of the present application is shown. Figure 3 As shown, in order to show it more clearly and directly, the horizontal axis is the ratio of the current equal-diameter length to the total equal-diameter length, and the vertical axis is the ratio of the crucible target rising distance to the equal-diameter length, that is, the first proportional coefficient.
[0083] In some embodiments, the single crystal growth method comprises:
[0084] Before the single crystal is generated, the target lifting distance of the crucible is calculated according to the target shoulder weight, target equal diameter and target equal length of the single crystal silicon and the actual size of the crucible;
[0085] The corresponding relationship curve is generated according to the crucible target rising distance when the target diameter length is different.
[0086] Figure 4 A graph showing the current position and target position of the crucible in the equal diameter stage of an embodiment of the present application is shown. The current position of the crucible in the graphite crucible is calculated based on a graphite crucible and a quartz crucible of standard size, a standard shoulder weight, and a crystal rod equal diameter of 308 mm. Figure 4 As shown, in order to show it more clearly and directly, the horizontal axis is the ratio of the current equal-diameter length to the total equal-diameter length, and the vertical axis is the crucible rising distance, wherein the dotted line curve is the target rising distance of the crucible in the equal-diameter stage, and the solid line curve is the actual rising distance of the crucible in the equal-diameter stage in an embodiment.
[0087] By simulating a standard curve of the crucible position as the equal diameter length increases, there will be an actual crucible position for each equal diameter length in the actual crystal pulling process. The two values are subtracted to calculate the deviation value, and the pulling speed can be calibrated through the relationship between the deviation value and the slope of the crucible position at the current position and the pulling speed, so as to achieve the purpose of defect-free crystal pulling.
[0088] Specifically, the target lifting distance of the crucible is calculated based on the target shoulder weight, target equal diameter and target equal length of the single crystal silicon and the actual size of the crucible, including:
[0089] According to the target shoulder weight, the target equal diameter and the target equal length, the target weight of the single crystal silicon is obtained;
[0090] According to the target weight of the single crystal silicon and the actual size of the crucible, the target lifting distance of the crucible is obtained.
[0091] It should be noted that the above method for obtaining the target lifting distance of the crucible based on the target weight of the single crystal silicon and the actual size of the crucible can adopt the existing method, which will not be elaborated here.
[0092] In some embodiments, the preset pulling speed is compensated by the deviation value between the current actual position of the crucible and the current target position, including steps S31 to S33, and each step is described in detail below.
[0093] In step S31, in the isodiametric growth stage, based on the current isodiametric length, a corresponding first proportional coefficient is obtained from a pre-obtained proportional relationship curve between the crucible rising distance and the isodiametric length.
[0094] In step S32, a compensation value of a preset pulling speed of the crucible is obtained according to the deviation value and the first proportionality coefficient.
[0095] Please continue reading Figure 4 After obtaining the actual lifting distance of the crucible in the equal diameter stage, based on the current equal diameter length, Figure 4 The crucible target rising distance, that is, the current target position of the crucible, can be obtained by real-time query in the corresponding relationship curve between the crucible rising distance and the equal diameter length, and then the deviation value between the two can be obtained.
[0096] Figure 5 A crucible position difference curve diagram of an equal diameter stage according to an embodiment of the present application is shown. Figure 5 It can be seen that the deviation between the two gradually increases.
[0097] Specifically, the compensation value of the preset pulling speed of the crucible is calculated according to the following formula:
[0098]
[0099] Among them, OPS is the compensation value of the preset pulling speed, in mm / min; △CP is the crucible position difference, in mm; SCP Slope is the first proportional coefficient, and K is the second proportional coefficient, whose size is related to the actual process parameters and generally ranges from -1 to 1.
[0100] In step S33, the preset pulling speed is compensated based on the compensation value to obtain the current pulling speed of the crucible.
[0101] Specifically, during the entire equal diameter process, the compensation value can be compensated to the initial set pulling speed through the programmable logic controller to achieve defect-free crystal pulling. According to the above formula, when the actual crucible position is 1 mm larger than the target crucible position, the pulling speed required to be compensated for different lengths is different. For example, at 50% length, the pulling speed needs to be increased by 0.1%-0.8%. When the actual crucible position is 1 mm smaller than the target crucible position, the pulling speed required to be compensated for different lengths is different. For example, at 50% length, the pulling speed needs to be reduced by 0.1%-0.8%, which can achieve defect-free crystal pulling.
[0102] So far, the introduction of the relevant steps of the silicon single crystal growth method of the embodiment of the present invention has been completed. It can be understood that the silicon single crystal growth method of this embodiment not only includes the above steps, but also may include other necessary steps before, during or after the above steps, which are all included in the scope of the growth method of this embodiment.
[0103] The present application also provides a control device.
[0104] Next, see Figure 6 To illustrate a control device according to an embodiment of the present application.
[0105] like Figure 6 As shown, the control device 60 includes: a memory 61 and a processor 62;
[0106] The memory 61 is used to store computer programs;
[0107] The processor 62 is used to execute the computer program stored in the memory 61 so as to enable the control device 60 to execute the single crystal growth method described in any of the above embodiments.
[0108] The memory 61 includes: ROM, RAM, disk, USB flash drive, memory card or optical disk, etc., which can store program codes.
[0109] Preferably, the processor 62 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.
[0110] It should be noted that it should be understood that the division of the various functional units of the above modules is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And these units can all be implemented in the form of software called by processing elements; they can also be all implemented in the form of hardware; they can also be partially implemented in the form of software called by processing elements, and partially implemented in the form of hardware. For example, the processor can be a separately established processing element, or it can be integrated in a chip of the above-mentioned device. In addition, it can also be stored in the memory of the above-mentioned device in the form of program code, and called and executed by a processing element of the above-mentioned device. The implementation of other modules is similar. In addition, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each module above can be completed by an integrated logic circuit of hardware in the processor element or instructions in the form of software.
[0111] The present application also provides a single crystal growth device.
[0112] like Figure 7 As shown, the single crystal growth device 70 includes:
[0113] The crystal growth furnace 71 is used to melt silicon material and solidify and crystallize it to obtain a single crystal silicon ingot;
[0114] The control device 72 is used to control the pulling speed of the seed crystal during the growth of single crystal silicon according to the single crystal growth method described in any of the above embodiments.
[0115] Specifically, the control device 72 is electrically connected to the crystal growth furnace 71 .
[0116] In some embodiments, the control device 72 can be any one of a programmable logic controller (PLC), an application specific integrated circuit (ASIC), and a field programmable gate array (FPGA).
[0117] In some embodiments, the crystal growth furnace 71 includes:
[0118] A furnace body, wherein a heat-insulating layer is provided on the inner side of the furnace body;
[0119] The crucible is arranged in the furnace body and is used to carry molten silicon, and one end of the single crystal is in contact with the liquid surface of the molten silicon;
[0120] A guide tube is arranged in the furnace body and extends from the outside of the crucible to the top of the molten silicon;
[0121] A single crystal pulling device, connected to the other end of the single crystal, is used to pull the single crystal during the single crystal growth process;
[0122] The heater is arranged between the crucible and the heat-insulating layer.
[0123] The structures of various devices or components in the crystal growth furnace can be implemented using existing technologies and will not be described in detail here.
[0124] Although multiple embodiments are described herein, it should be understood that a variety of other modifications and embodiments may be conceived by those skilled in the art, all of which will fall within the spirit and scope of the concepts disclosed herein. More particularly, various modifications and changes may be made to the arrangements and / or components of the subject matter in combination within the scope of the disclosure, drawings, and appended claims. In addition to modifications and changes to components and / or arrangements, the use of alternatives is also an obvious option for those skilled in the art.
Claims
1. A single crystal growth method, characterized in that: include: Placing silicon material in a crucible of a crystal growth furnace; heating the crucible to melt the silicon material into a silicon melt; The seed crystal is immersed in the silicon melt, and the seed crystal is rotated and pulled upward at a current pulling speed, so that the silicon melt solidifies and crystallizes at the lower end of the seed crystal to obtain a single crystal silicon crystal rod; wherein the preset pulling speed is compensated by the deviation value between the current actual position of the crucible and the current target position to obtain the current pulling speed to control the ratio of the current pulling speed of the crucible to the temperature gradient.
2. The single crystal growth method according to claim 1, characterized in that: The method of compensating the preset pulling speed by the deviation between the current actual position of the crucible and the current target position includes: In the isodiameter growth stage, based on the current isodiameter length, a corresponding first proportional coefficient is obtained from a pre-obtained proportional relationship curve between the crucible rising distance and the isodiameter length; Obtaining a compensation value of a preset pulling speed of the crucible according to the deviation value and the first proportional coefficient; The preset pulling speed is compensated based on the compensation value to obtain a current pulling speed of the crucible.
3. The single crystal growth method according to claim 2, characterized in that: Before compensating the preset pulling speed by the deviation value between the current actual position of the crucible and the current target position, the method further includes: Obtaining a pre-generated corresponding relationship curve between the crucible rising distance and the equal diameter length; Based on the current equal diameter length, the current target position of the crucible is obtained from the corresponding relationship curve.
4. The single crystal growth method according to claim 3, characterized in that: Before obtaining the pre-generated corresponding relationship curve of the crucible rising distance and the equal diameter length, it also includes: Calculate the target lifting distance of the crucible according to the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible; The corresponding relationship curve is generated according to the crucible target rising distance when the target diameter length is different.
5. The single crystal growth method according to claim 2, characterized in that: Also includes: Calculate the target lifting distance of the crucible according to the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible; According to the crucible target rising distance and the target equal diameter length, obtaining a ratio of the crucible target rising distance to the target equal diameter length; The proportional relationship curve is generated according to the ratio of the crucible target rising distance to the target equal diameter length at different target equal diameter lengths.
6. The single crystal growth method according to claim 4 or 5, characterized in that: The method of calculating the target lifting distance of the crucible according to the target shoulder weight, target equal diameter and target equal length of the silicon monocrystalline and the actual size of the crucible comprises: Obtaining a target weight of the single crystal silicon according to the target shoulder weight, the target equal-diameter diameter and the target equal-diameter length; The target lifting distance of the crucible is obtained according to the target weight of the silicon single crystal and the actual size of the crucible.
7. The single crystal growth method according to claim 1, characterized in that: Placing silicon material in the crucible of the crystal growth furnace comprises: Putting silicon material into the crucible; The crystal growth furnace is closed and evacuated, and a protective gas is filled into the crystal growth furnace, wherein the protective gas includes argon.
8. The single crystal growth method according to claim 1, characterized in that: When the crucible is heated, the heating temperature is greater than or equal to 1420°C.
9. A control device, characterized in that: include: Processor and memory; The memory is used to store computer programs; The processor is used to execute the computer program stored in the memory so that the control device performs the single crystal growth method according to any one of claims 1 to 8.
10. A single crystal growth device, characterized in that: include: A crystal growth furnace is used to melt silicon material and solidify and crystallize it to obtain a single crystal silicon ingot; A control device for controlling the pulling speed of the seed crystal during the growth of the single crystal silicon according to the single crystal growth method according to any one of claims 1 to 8.