Superconducting magnet for monocrystalline silicon drawing process and process magnetic field adjusting method
By combining movable coil components and magnetically controlled sliding sleeves, rapid, flexible, and precise magnetic field adjustment of superconducting magnets is achieved, solving the problems of poor versatility and difficulty in adjustment in existing technologies, and improving production efficiency and yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG JINGSHENG MECHANICAL & ELECTRICAL CO LTD
- Filing Date
- 2026-01-22
- Publication Date
- 2026-05-05
AI Technical Summary
Existing superconducting magnets have poor versatility, are difficult to adjust the magnetic field, are hard to adapt to crucibles of different sizes and crystal pulling process requirements, and are costly.
Electromagnetic drive is achieved by using movable first and second coil assemblies, combined with magnetically controlled sliding sleeves for positioning, enabling rapid, flexible, and precise adjustment of the magnetic field.
This improves the versatility and production efficiency of superconducting magnets, reduces the difficulty and cost of magnetic field adjustment, and increases the yield rate.
Smart Images
Figure CN121983407A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of single crystal preparation technology, and in particular to a superconducting magnet for single crystal silicon pulling process and a method for adjusting the process magnetic field. Background Technology
[0002] In the crystal pulling process of semiconductor materials such as single-crystal silicon, the magnetron Czochralski (MCZ) method is typically used within a single-crystal furnace. The MCZ method precisely controls the growth process and final crystal quality by applying a specific magnetic field outside the magnetofluid within the single-crystal furnace to suppress thermal convection in the magnetofluid. This magnetic field is usually generated by a superconducting magnet positioned outside the single-crystal furnace.
[0003] However, existing mainstream four-coil superconducting magnets typically have a fixed structure. This fixed structure can only generate a fixed magnetic field distribution, and the process window for this fixed magnetic field is very small, resulting in insufficient versatility in magnetic field adjustment. Specifically, when dealing with crucibles of different sizes (e.g., mainstream 24-inch, 28-inch, 32-inch, and 36-inch sizes) or different crystal pulling process requirements, the fixed magnetic field distribution is difficult to provide a satisfactory process window, potentially requiring repeated, time-consuming, and laborious manual adjustments, or even complete magnet replacement. Although there are solutions that utilize six-coil superconducting magnets and adjust the current in the corresponding superconducting magnet coils to adjust the magnetic field, this technology requires additional coils and corresponding cryogenic cooling systems, making it too costly.
[0004] Therefore, how to improve the versatility and / or process adaptability of superconducting magnets in a low-cost and effective manner is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] This application aims to solve the technical problems of poor versatility of superconducting magnets and difficulty in magnetic field adjustment in the prior art, and provides a superconducting magnet for single crystal silicon pulling process and a method for adjusting the process magnetic field, so as to achieve rapid, flexible and precise adjustment of the crystal pulling magnetic field.
[0006] To achieve the above objectives, this application provides a superconducting magnet for single-crystal silicon pulling processes, comprising a body, at least one pair of coil carriers, a first coil assembly mounted on each coil carrier, a second coil assembly mounted on each coil carrier, and a magnetically controlled sliding sleeve; the coil carriers are movably mounted on the body; the first coil assembly is used to generate a process magnetic field; the second coil assembly is used to drive the pair of coil carriers to move by generating electromagnetic force; the magnetically controlled sliding sleeve is used to position or unlock the coil carriers from the body, and the magnetically controlled sliding sleeve includes a third coil assembly for changing the fluid state of a magnetic fluid; when the third coil assembly is de-energized, the magnetic fluid is in a low-viscosity fluid state, and the magnetically controlled sliding sleeve is in an unlocked first state; when the third coil assembly is energized, the magnetic fluid is in a high-viscosity fluid state, and the magnetically controlled sliding sleeve is in a positioned second state.
[0007] In some embodiments, the body is a ring structure and is provided with at least one section of slide rail. The coil carrier is mounted on the slide rail by a magnetically controlled sliding sleeve and can move along the slide rail.
[0008] In some embodiments, an adjustable angle is formed between the axes of a pair of first coil assemblies.
[0009] In some embodiments, a second coil assembly is mounted between a pair of coil carriers. By passing currents in different directions through the second coil assembly, electromagnetic forces that attract or repel each other are generated, thereby driving the pair of coil carriers to move closer or further apart along a slide rail.
[0010] In some embodiments, a second coil assembly is mounted on each of the opposite end faces of a pair of coil carriers. When currents of different directions are passed through the pair of second coil assemblies, electromagnetic forces that attract or repel each other are generated, and the second coil assemblies move closer or further away from each other along the slide rail with the coil carriers.
[0011] Alternatively, a pair of second coil assemblies are provided between the opposing end faces of a pair of coil carriers. The pair of second coil assemblies are fixed to the main body. When currents of different directions are passed through the pair of second coil assemblies, electromagnetic forces that attract or repel each other are generated, and the coil carriers move closer or further apart along the slide rail.
[0012] In some embodiments, the slide rail is provided with a slide rail positioning groove. When the magnetically controlled slide sleeve is in the second state, the magnetic fluid cooperates with the slide rail positioning groove to achieve the positioning of the coil carrier.
[0013] Secondly, this application also provides a method for adjusting the magnetic field in a single-crystal silicon pulling process, applied to the aforementioned superconducting magnet, the method comprising: Power is de-energized to the third coil assembly, placing the magnetically controlled sliding sleeve in the unlocked first state to allow the coil carrier to move; When the second coil assembly is energized, an electromagnetic force is generated to drive the coil carrier to move along the body to the target position; Once the coil carrier reaches the target position, the third coil assembly is energized to switch the magnetically controlled sliding sleeve to the second positioning state, thereby fixing the coil carrier. The first coil assembly is energized to generate a process magnetic field.
[0014] In some embodiments, energizing the second coil assembly to generate an electromagnetic force to drive the coil carrier to move along the body to a target position includes: By controlling the direction of the current flowing into the second coil assembly, electromagnetic forces that attract or repel each other are selectively generated to drive the coil carriers closer or further apart.
[0015] In some embodiments, the superconducting magnet includes two pairs of first coil assemblies, and the magnetic field adjustment method adjusts the included angle between the axes of the two pairs of first coil assemblies by moving the position of the coil carrier.
[0016] In some embodiments, before de-energizing the third coil assembly to place the magnetically controlled slide in an unlocked first state to allow movement of the coil carrier, the method further includes: The first and second coil assemblies are de-energized and demagnetized.
[0017] Compared with the prior art, this application has the following beneficial effects: This application achieves rapid, flexible, and precise adjustment of the crystal pulling magnetic field by setting a movable first coil assembly, using a second coil assembly for electromagnetic drive, and employing a magnetically controlled sliding sleeve containing a magnetofluid for positioning. This solution effectively solves the problems of poor versatility of superconducting magnets and difficulty in magnetic field adjustment in existing technologies, improving production efficiency and yield, while maintaining a relatively simple structure and good cost control. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the structure of a superconducting magnet provided in an embodiment of this application.
[0019] Figure 2 This is a schematic diagram of a magnetically controlled sliding sleeve provided in an embodiment of this application.
[0020] Figure 3 This is a cross-sectional view of the magnetically controlled sliding sleeve along the AA direction provided in an embodiment of this application.
[0021] Figure 4 This is a schematic diagram showing the included angle between the axes of a pair of first coils in a superconducting magnet provided in an embodiment of this application.
[0022] Figure 5 This is a schematic diagram illustrating the repulsive electromagnetic force generated between a pair of second coil components provided in an embodiment of this application.
[0023] Figure 6 This is a schematic diagram illustrating the generation of an attractive electromagnetic force between a pair of second coil components, as provided in an embodiment of this application.
[0024] Figure 7 A flowchart illustrating the method for adjusting the magnetic field in the single-crystal silicon pulling process provided in this application embodiment. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings.
[0026] It should be noted that in the specification, claims, and accompanying drawings of this application, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should also be understood that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.
[0027] This application provides a superconducting magnet 1, which is particularly suitable for single crystal furnaces, for applying a specific magnetic field during the pulling process of semiconductor materials such as single crystal silicon to suppress thermal convection in the magnetofluid, thereby precisely controlling the growth process of the single crystal and the final crystal quality.
[0028] like Figure 1 As shown, the superconducting magnet 1 includes a body 10, at least one pair of coil carriers 20, a first coil assembly 30 and a second coil assembly 40 mounted on the body 10 via the coil carriers 20, and each coil carrier 20 is provided with a first coil assembly 30 and a second coil assembly 40. The body 10 has a ring structure, and a slide rail 11 is provided along the circumference of the ring structure. The body 10 also includes a magnetically controlled sliding sleeve 12 mounted on the slide rail 11 and slidable along the extension direction of the slide rail 11.
[0029] like Figure 2 and Figure 3 As shown, the magnetically controlled sliding sleeve 12 includes a sliding sleeve housing 121, positioning blocks 122 located at both ends of the sliding sleeve housing 121, and a third coil assembly 124. A cavity 123 is formed inside the sliding sleeve housing 121, and the third coil assembly 124 can be disposed in the cavity 123. The coil carrier 20 is provided with a storage space to store the corresponding slide rail 11 and the magnetically controlled sliding sleeve 12 mounted thereon, and is provided with a positioning plate 21 that is fastened to the positioning block 122, thereby allowing the coil carrier 20 to move along the slide rail 11.
[0030] The third coil assembly 124 of the magnetically controlled sliding sleeve 12 encloses and houses the magnetic fluid. The third coil assembly 124 includes a third coil frame and a third coil. The slide rail 11 includes a slide rail positioning groove 111 for housing the magnetic fluid. When the third coil is not energized, no magnetic field is applied in the cavity 123, and the magnetically controlled sliding sleeve 12 is in its first working state, i.e., the magnetic fluid is in a Newtonian fluid state, and the magnetically controlled sliding sleeve 12 can slide freely along the slide rail 11. When the third coil is energized, a magnetic field is applied in the cavity 123, and the magnetically controlled sliding sleeve 12 is in its second working state, i.e., the magnetic fluid is in a Bingham fluid state. The magnetic fluid will instantly solidify, transforming into a quasi-solid or even solid-like substance with high damping / high viscosity, which cooperates with the slide rail positioning groove 11 to achieve the positioning of the corresponding magnetically controlled sliding sleeve 12 on the slide rail 11.
[0031] like Figure 4 and Figure 5 As shown, the first coil assembly 30 includes a first coil frame 31 and a first coil 32. The first coil frame 31 is mounted on the outer side of the coil carrier 20 away from the center of the annular structure of the body 10. The first coil 32 is wound around the first coil frame 31, and the axis of the first coil 32 is aligned with the axis of the annular structure of the body 10. The first coil 32 is a superconducting coil used to generate the process magnetic field, i.e., the transverse magnetic field for realizing the single crystal pulling process.
[0032] The second coil assembly 40 includes a second coil frame 41 and a second coil 42. The second coil frame 41 is mounted on one end face of the coil body 20, and this end face is perpendicular to the circumferential direction of the body 10. The second coil 42 is wound around the second coil frame 41, and the axis of the second coil 42 is tangent to the circumferential direction of the annular structure of the body 10.
[0033] In this embodiment, the superconducting magnet 1 includes at least one pair of coil carriers 20, and the axis of the first coil assembly 30 disposed on the pair of coil carriers 20 forms an included angle θ. Specifically, the first coil 32 is wound around the first coil frame 31 along the circumferential direction of the first coil frame 31, and the axis of the first coil assembly 30 coincides with the center line of the circular area formed by the first coil 32. The second coil 42 is mounted on the end face of one coil body 20 near the other coil body 20.
[0034] The slide rail 11 is divided into two sections, which are close enough but not connected. The degree of closeness between the two slide rail sections and the length of each slide rail section satisfy the specific angular requirements between the first coil assembly 30 described below.
[0035] The movement of the coil carrier 20 on the slide rail 11, changing the position of the coil carrier 20 on the slide rail 11, is driven by the electromagnetic force generated by the second coil 42. Specifically, in Figure 5 From the provided perspective, currents flow from top to bottom and from bottom to top respectively through the second coil 42 of each of the pair of coil carriers 20. Based on the right-hand rule, a repulsive electromagnetic force F1 is generated between the pair of second coils 42. If one of the coil carriers 20 or both of the coil carriers 20 are movable, this electromagnetic force F1 will push one coil carrier 20 with a second coil 42 away from the other coil carrier 20 with a second coil 42. Similarly, in Figure 6From the provided perspective, a top-down current is passed through the second coil 42 of each of the pair of coil carriers 20. Based on the right-hand rule, an electromagnetic force F2 is generated between the pair of second coils 42. If one of the coil carriers 20 or both of the coil carriers 20 are movable, the electromagnetic force F2 will pull one coil carrier 20 with a second coil 42 closer to the other coil carrier 20 with a second coil 42.
[0036] In some embodiments, the superconducting magnet 1 includes at least two pairs of coil carriers 20, and a partition plate 13 fixed to the slide rail 11 is provided between adjacent pairs of coil carriers 20 (see Figure 1 Furthermore, the partition plate 13 cannot move relative to the slide rail 11. Each pair of coil carriers 20 is arranged in the manner described above, such that the axes of the two first coil assemblies 30 in any pair of coil carriers 20 form an included angle θ.
[0037] The slide rails 11 are divided into two groups, and the two groups of slide rails 11 are horizontally placed on both sides of the ring structure. Each group of slide rails 11 has two slide rails 11 that are close enough but not connected. The degree of closeness between the two slide rails 11 and the length of each slide rail 11 meet the specific angle requirements between the first coil assembly 30 described below.
[0038] When a pair of coil carriers 20, each carrying its own first coil 32, are in a first position on the slide rail 11, a first included angle θ1 is formed between the axes of the pair of first coil assemblies 30. When a pair of coil carriers 20, each carrying its own first coil 32, are in a second position on the slide rail 11, a second included angle θ2 is formed between the axes of the pair of first coil assemblies 30. The angle difference between the first included angle θ1 and the second included angle θ2 ranges from 5° to 15°. Further, the angle difference between the first included angle θ1 and the second included angle θ2 ranges from 7° to 13°. Preferably, the angle difference between the first included angle θ1 and the second included angle θ2 ranges from 10°. This arrangement prevents the pair of coil carriers 20 from moving away from each other under the action of the electromagnetic force F, thus avoiding interference between the process magnetic field generated by the first coil 32 on one pair of coil carriers 20 and the process magnetic field generated by the first coil 32 on the other pair of coil carriers 20. Furthermore, it prevents the pair of coil carriers 20 from moving closer together under the action of the electromagnetic force F, thus avoiding overlap of the process magnetic fields generated by the first coil 32 on the pair of coil carriers 20.
[0039] In some embodiments, the superconducting magnet 1 further includes a control unit and a power supply. The control unit and the power supply are electrically connected to the first coil 32, the second coil 42, and the third coil, providing controlled current to each coil.
[0040] In summary, this application achieves rapid, flexible, and precise adjustment of the crystal pulling magnetic field by setting a movable first coil assembly 30, using a second coil assembly 40 for electromagnetic drive, and employing a magnetically controlled sliding sleeve 12 containing a magnetic fluid for positioning. This solution effectively solves the problems of poor versatility of superconducting magnets and difficulty in magnetic field adjustment in existing technologies, improves production efficiency and yield, and has a relatively simple structure and good cost control.
[0041] like Figure 7 As shown in the embodiments of this application, a method for adjusting the magnetic field in the single-crystal silicon pulling process is also provided, applied to the aforementioned superconducting magnet. This adjustment method includes: Step S701: De-energize the third coil assembly 124 to put the magnetically controlled sliding sleeve 12 in the unlocked first state to allow the coil carrier 20 to move.
[0042] For example, the current control of the third coil assembly 124 is realized by the control unit. Before the third coil assembly 124 is de-energized and demagnetized, the control unit de-energizes and demagnetizes all the first coils 32 and the second coils 42 to ensure that the magnetofluid is in a Newtonian fluid state, and the magnetically controlled sliding sleeve 12 can slide freely along the slide rail 11.
[0043] Step S702: Power on the second coil assembly 40 to generate electromagnetic force to drive the coil carrier 20 to move along the circumference of the body 10 to the target position.
[0044] For example, the control unit sets the target position of the first coil assembly 30 on the slide rail 11 according to process requirements and / or crucible size, etc. The control unit controls the direction of the current supplied to the second coil assembly 40, selectively generating attractive or repulsive electromagnetic forces to drive the coil carriers 20 closer to or further apart from each other. By moving the position of the coil carriers 20, the included angle θ between the axes of the pair of first coil assemblies 30 is adjusted.
[0045] Specifically, the control unit applies a current in the corresponding direction that will generate an attractive electromagnetic force according to the right-hand rule to the second coil 42 on a pair of coil carriers 20, thereby generating a pulling force between the pair of coil carriers 20 and driving the coil carriers 20 to move along the slide rail 11 to the target position, so that the included angle θ between the axes of the first coil assembly 30 decreases.
[0046] Alternatively, the control unit can supply a current in the corresponding direction that will generate a repulsive electromagnetic force according to the right-hand rule to the second coil 42 on a pair of coil carriers 20, thereby generating a thrust between the pair of coil carriers 20 and driving the coil carriers 20 to move along the slide rail 11 to the target position, thereby increasing the included angle θ between the axes of the first coil assembly 30.
[0047] Step S703: After the coil carrier 20 reaches the target position, the third coil assembly 124 is energized to switch the magnetically controlled sliding sleeve 12 to the second positioning state to fix the coil carrier 20.
[0048] For example, when either coil carrier 20 reaches the target position, the control unit energizes the third coil and positions the coil carrier 20 by positioning the corresponding magnetically controlled sliding sleeve 12. When both coil carriers 20 reach the target position, the second coil 42 of the corresponding second coil assembly 40 is de-energized.
[0049] Step S704: Energize the first coil assembly 30 to generate a process magnetic field.
[0050] For example, the control unit energizes each of the first coils 32 to provide a process magnetic field for the single crystal furnace. If necessary, the current supplied to each of the first coils 32 can be different to further provide additional magnetic field variations and increase the versatility of the superconducting magnet 1.
[0051] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A superconducting magnet for single-crystal silicon pulling process, characterized in that, include: Ontology(10); At least one pair of coil carriers (20) are movably mounted on the body (10); The first coil assembly (30) installed on each of the coil carriers (20) is used to generate a process magnetic field; The second coil assembly (40) mounted on each of the coil carriers (20) is used to drive a pair of the coil carriers (20) to move by generating an electromagnetic force; A magnetically controlled sliding sleeve (12) is used to position or unlock the coil carrier (20) to the body (10). The magnetically controlled sliding sleeve (12) includes a third coil assembly (124) for changing the fluid state of the magnetic fluid. When the third coil assembly (124) is de-energized, the magnetic fluid is in a low-viscosity fluid state, and the magnetically controlled sliding sleeve (12) is in an unlocked first state. When the third coil assembly (124) is energized, the magnetic fluid is in a high-viscosity fluid state, and the magnetically controlled sliding sleeve (12) is in a positioned second state.
2. The superconducting magnet according to claim 1, characterized in that, The main body (10) is a ring structure and is provided with at least one section of slide rail (11). The coil carrier (20) is installed on the slide rail (11) through the magnetic control slide sleeve (12) and can move along the slide rail (11).
3. The superconducting magnet according to claim 2, characterized in that, An adjustable angle is formed between the axes of a pair of the first coil assemblies (30).
4. The superconducting magnet according to claim 3, characterized in that, The second coil assembly (40) is installed between the pair of coil carriers (20). By passing currents in different directions through the second coil assembly (40), electromagnetic forces that attract or repel each other are generated, thereby driving the pair of coil carriers (20) to move closer or further apart along the slide rail (11).
5. The superconducting magnet according to claim 3, characterized in that, The second coil assembly (40) is installed on the opposite end faces of the pair of coil carriers (20). When currents of different directions are passed into the pair of second coil assemblies (40), electromagnetic forces that attract or repel each other are generated. The second coil assemblies (40) move closer or further away from each other along the slide rail (11) with the coil carriers (20). Alternatively, a pair of second coil assemblies (40) are provided between the opposing end faces of a pair of coil carriers (20), and the pair of second coil assemblies (40) are fixed to the body (10). When currents of different directions are passed into the pair of second coil assemblies (40), electromagnetic forces that attract or repel each other are generated, and the coil carriers (20) move closer or further away from each other along the slide rail (11).
6. The superconducting magnet according to claim 2, characterized in that, The slide rail (11) is provided with a slide rail positioning groove (111). When the magnetic control slide sleeve (12) is in the second state, the magnetic fluid cooperates with the slide rail positioning groove (111) to position the coil carrier (20).
7. A method for adjusting the magnetic field in a single-crystal silicon pulling process, applied to the superconducting magnet as described in any one of claims 1-6, characterized in that, The adjustment method includes: Power is de-energized to the third coil assembly (124), and the magnetically controlled sliding sleeve (12) is placed in an unlocked first state to allow the coil carrier (20) to move; When the second coil assembly (40) is energized, an electromagnetic force is generated to drive the coil carrier (20) to move along the body (10) to the target position; When the coil carrier (20) reaches the target position, the third coil assembly (124) is energized, so that the magnetically controlled sliding sleeve (12) switches to the second positioning state to fix the coil carrier (20); The first coil assembly (30) is energized to generate a process magnetic field.
8. The method for adjusting the magnetic field in the single-crystal silicon pulling process according to claim 7, characterized in that, The step of energizing the second coil assembly (40) to generate an electromagnetic force to drive the coil carrier (20) to move along the body (10) to the target position includes: By controlling the direction of the current flowing into the second coil assembly (40), electromagnetic forces that attract or repel each other are selectively generated to drive the coil carriers (20) closer to or further apart.
9. The method for adjusting the magnetic field in the single-crystal silicon pulling process according to claim 7, characterized in that, The superconducting magnet includes a pair of first coil assemblies (30), and the adjustment method adjusts the included angle between the axes of the pair of first coil assemblies (30) by moving the position of the coil carrier (20).
10. The method for adjusting the magnetic field in the single-crystal silicon pulling process according to any one of claims 7-9, characterized in that, Before de-energizing the third coil assembly (124) to place the magnetically controlled sliding sleeve (12) in an unlocked first state to allow the coil carrier (20) to move, the method further includes: The first coil assembly (30) and the second coil assembly (40) are de-energized and demagnetized.