Thermal field adjusting device, single crystal furnace and thermal field adjusting method

Abstract

The invention provides a thermal field adjusting device, a single crystal furnace and a thermal field adjusting method.The thermal field adjusting device is applied to the single crystal furnace, the single crystal furnace comprises a furnace body, a guide cylinder is arranged in the furnace body, the center of the guide cylinder is arranged to be a crystal bar lifting area, and the thermal field adjusting device is arranged between the inner side wall of the guide cylinder and the crystal bar lifting area; the thermal field adjusting device comprises an electric heating film and an electrode layer which are stacked in the radial direction of the guide cylinder, and a control unit arranged outside the furnace body; the control unit is configured to adjust the intensity of an electric field applied to the electric heating film by controlling the power-on state of the electrode layer, so that the electric heating film is switched between a heat absorption state and a heat release state. Based on the electrothermal effect principle, the control unit controls the electrode layer to be powered on and powered off so that the electrothermal film can be switched between the heat absorption state and the heat release state, the response speed of a thermal field can be remarkably increased, and instantaneous temperature fluctuation can be effectively restrained.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor product manufacturing technology, and in particular to a thermal field conditioning device, a single crystal furnace, and a thermal field conditioning method. Background Technology

[0002] There are two main methods for manufacturing single-crystal silicon rods: the zone melting method and the Czeklaussky method, with the Czeklaussky method (CZ method) being the most commonly used. Under argon protection, the CZ method involves placing polycrystalline silicon material in a quartz crucible within a crystal pulling furnace. The polycrystalline silicon material is melted by a heater to obtain molten silicon, which is then continuously kept at a constant temperature. A rod-shaped seed crystal (called a seed crystal) is brought into contact with the surface of the molten silicon. At a suitable temperature, silicon atoms in the molten silicon crystallize regularly at the solid-liquid interface, following the atomic arrangement of the seed crystal, forming a single crystal. The seed crystal is then rotated and pulled, allowing the silicon atoms in the molten silicon to continue crystallizing on the previously formed single crystal, maintaining their regular atomic arrangement. This process accelerates the pulling process, producing a single-crystal silicon rod with the target diameter and quality. However, current CZ method single-crystal silicon growth processes suffer from technical defects such as high thermal inertia, crude control methods leading to low precision and poor stability in crystal growth process control. Summary of the Invention

[0003] To address the aforementioned technical problems, this disclosure provides a thermal field conditioning device, a single crystal furnace, and a thermal field conditioning method, thereby resolving the issue of poor thermal field stability.

[0004] To achieve the above objectives, the technical solution adopted in this disclosure is: a thermal field regulating device applied to a single crystal furnace, the single crystal furnace including a furnace body, a flow guide cylinder disposed within the furnace body, and the center of the flow guide cylinder being designated as a crystal rod pulling region.

[0005] The thermal field adjustment device is disposed between the inner wall of the guide tube and the crystal rod pulling area. The thermal field adjustment device includes: an electrothermal film and an electrode layer stacked along the radial direction of the guide tube, and a control unit externally disposed in the furnace body.

[0006] The control unit is configured to adjust the intensity of the electric field applied to the electrothermal film by controlling the energization state of the electrode layer, so that the electrothermal film switches between an endothermic state and an exothermic state.

[0007] Optionally, in the axial direction of the guide tube, the electrode layer includes a plurality of first sub-electrode layers spaced apart.

[0008] Optionally, the control unit includes a first control unit for independently controlling the energizing state of multiple first sub-electrode layers.

[0009] Optionally, the control unit includes a second control unit for synchronously controlling the energizing state of multiple first sub-electrode layers.

[0010] Optionally, at least one of the first sub-electrode layers includes a plurality of second sub-electrode layers in the circumferential direction of the guide tube.

[0011] Optionally, the control unit further includes a third control unit for independently controlling the energizing state of the plurality of second sub-electrode layers.

[0012] Optionally, an insulating portion is provided between adjacent first sub-electrode layers.

[0013] Optionally, in the axial direction of the guide tube, the inner wall of the guide tube includes a first portion near the top of the furnace body and a second portion away from the top of the furnace body, and the electrothermal film of the guide tube is disposed on the inner wall of the guide tube and at least covers the second portion.

[0014] Optionally, an insulating layer is provided between the electrothermal film and the flow guide tube.

[0015] Optionally, a protective layer is provided on the side of the electrode layer away from the guide tube.

[0016] Optionally, the control unit is configured to apply a DC voltage to the electrode layer, or the control unit is configured to adjust the duty cycle of the target voltage applied to the electrode layer within a fixed period by means of pulse width modulation, so as to control the electric field strength applied to the electrothermal film.

[0017] Optionally, it also includes a crystal rod diameter measuring structure for measuring the diameter of the crystal rod in real time and transmitting a signal to the control unit. The control unit is configured to increase the electric field strength when the signal indicates that the measured diameter of the crystal rod is less than a preset diameter, and to decrease the electric field strength when the signal indicates that the measured diameter of the crystal rod is greater than the preset diameter.

[0018] This disclosure also provides a single crystal furnace, including a furnace body and the aforementioned thermal field conditioning device disposed within the furnace body.

[0019] This disclosure also provides a thermal field conditioning method applied to the above-described thermal field conditioning device, the thermal field conditioning method comprising:

[0020] Measure the diameter of the crystal rod;

[0021] When the measured diameter of the crystal rod is smaller than the preset diameter, the electric field strength applied to the electrothermal film is increased to increase the heat release of the electrothermal film. When the measured diameter of the crystal rod is larger than the preset diameter, the electric field strength applied to the electrothermal film is decreased to increase the heat absorption of the electrothermal film.

[0022] The beneficial effects of this disclosure are as follows: The thermal field adjustment device provided by this disclosure is disposed between the inner wall of the guide tube and the crystal rod pulling area. The thermal field adjustment device includes: an electrothermal film and an electrode layer stacked along the radial direction of the guide tube, and a control unit externally disposed in the furnace body. Based on the principle of electrothermal effect, the control unit controls the on and off of the electrode layer to make the electrothermal film switch between the heat absorption state and the heat release state, which can significantly improve the response speed of the thermal field and effectively suppress instantaneous temperature fluctuations. Attached Figure Description

[0023] Figure 1 A schematic diagram showing the distribution of electric dipoles when no electric field is applied;

[0024] Figure 2 A schematic diagram showing the distribution of electric dipoles under the influence of an electric field;

[0025] Figure 3 A schematic diagram showing the structure of a single crystal furnace;

[0026] Figure 4 This is a schematic diagram of the thermal field control device. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0028] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0029] refer to Figure 3 and Figure 4 This embodiment provides a thermal field adjustment device applied to a single crystal furnace. The single crystal furnace includes a furnace body, a flow guide cylinder 1, a crucible, and a heater 2 arranged around the crucible. The center of the flow guide cylinder 1 is designated as a crystal rod pulling region.

[0030] The heat field adjustment device is disposed between the inner side wall of the guide tube 1 and the crystal rod pulling area. The heat field adjustment device includes: an electrothermal film 3 and an electrode layer 7 stacked along the radial direction of the guide tube 1, and a control unit 5 externally placed in the furnace body. The control unit is connected to the electrode layer 7 via a connecting line 4.

[0031] The control unit 5 is configured to adjust the intensity of the electric field applied to the electrothermal film 3 by controlling the energizing state of the electrode layer 7, so that the electrothermal film 3 switches between a heat-absorbing state and a heat-releasing state.

[0032] The control unit 5 is configured to switch the electrothermal film 3 between a heat-absorbing state and a heat-releasing state by energizing or de-energizing the electrode layer 7. Specifically, the control unit 5 energizes the electrode layer 7 to apply an electric field to the electrothermal film 3, causing the electrothermal film 3 to be in the heat-releasing state. The control unit 5 stops energizing the electrode layer and removes the electric field applied to the electrothermal film 3, causing the electrothermal film 3 to be in the heat-absorbing state.

[0033] The operation of the electrothermal thin film 3 is based on a reversible electrothermal effect, which is essentially a thermodynamic process driven by an electric field to change the polarization state of the material, accompanied by the exchange of entropy and heat. Its operation can be divided into two stages: polarization exothermic under the influence of the electric field and depolarization endothermic after the electric field is removed.

[0034] Polarized Ordered Exothermic Process: When an external electric field is applied to the electrothermal film 3, the inherent electric dipoles inside the material are redirected under the influence of the electric field force, changing from a disordered state to an ordered arrangement. (Refer to...) Figure 1 and Figure 2 , Figure 1 This diagram illustrates the disordered state of an electric dipole when no electric field is applied. Figure 2 This diagram illustrates an electric dipole in an ordered state when an electric field is applied. Figure 2 The arrow in the diagram indicates the direction of the electric field E. This process causes a decrease in the polarization entropy of the material, while the total entropy of the system remains unchanged. To maintain the conservation of total entropy, the energy corresponding to this decrease in entropy will be released to the outside world in the form of heat energy. Macroscopically, this manifests as an instantaneous increase in the temperature of the electrothermal film, thereby releasing heat (heating) to the surrounding environment.

[0035] Depolarization disorder endothermic process: When the external electric field is removed or significantly weakened, the electric dipoles lose their electric field constraint and rapidly return to their initial disordered state under the influence of lattice thermal vibrations. This process leads to an increase in the material's polarization entropy. To maintain the system's energy balance, the electrothermal film absorbs equivalent thermal energy from its surrounding environment, macroscopically manifested as an instantaneous decrease in the film's temperature, thus achieving active heat absorption (cooling) of the surrounding environment.

[0036] The thermal field adjustment device provided in this embodiment includes an electrothermal film 3 and an electrode layer 7 stacked along the radial direction of the guide tube 1, and a control unit 5 externally placed in the furnace body. Based on the principle of electrothermal effect, the control unit 5 controls the on and off of the electrode layer 7 to make the electrothermal film 3 switch between heat absorption and heat release states, which can significantly improve the response speed of the thermal field and effectively suppress instantaneous temperature fluctuations.

[0037] In this embodiment, the thermal field adjustment device is disposed between the inner wall of the guide tube 1 and the crystal rod pulling area. The distance between the thermal field adjustment device and the crystal rod is smaller than the distance between the guide tube 1 and the crystal rod. The electrothermal effect originates from the order-disorder transition of the dipoles inside the electrothermal film 3 under the action of the electric field. This process occurs at the molecular scale and has an extremely high response speed. Compared with traditional heaters, it can achieve a faster thermal response, thereby enabling more precise thermal control.

[0038] For example, the distance between the guide tube 1 and the crystal rod pulling area is less than 10mm, and the thickness of the thermal field adjustment device in the radial direction of the guide tube 1 is 1-2mm, but not limited thereto.

[0039] In an exemplary embodiment, the electrode layer 7 may be a conductive film layer structure or a metal mesh structure.

[0040] In an exemplary embodiment, the electrode layer 7 is an integral structure, the electrode layer 7 is attached to the inner wall of the guide tube 1, and the electrode layer 7 is a cylindrical structure that conforms to the shape of the guide tube 1.

[0041] The electrode layer 7 adopts a complete and continuous integral structure, which can apply a uniform electric field to the surface of the electrothermal film 3, ensuring that the polarization / depolarization process in each region of the electrothermal film 3 is carried out synchronously, avoiding local thermal field distortion and improving the consistency of thermal regulation. In terms of process preparation, it can be directly prepared using mature thin film processes such as sputtering, evaporation, or coating, reducing the process difficulty and possessing good mechanical stability and high-temperature adaptability.

[0042] In an exemplary embodiment, in the axial direction of the guide tube 1, the electrode layer 7 includes a plurality of first sub-electrode layers spaced apart.

[0043] For example, an insulating portion 9 is provided between adjacent first sub-electrode layers. Thus, each appropriate first sub-electrode layer can be controlled independently or in groups, thereby enabling the formation of multiple independently controllable thermally modulated zones along the axial direction.

[0044] In an exemplary embodiment, the control unit 5 includes a first control unit for independently controlling the energizing state of multiple first sub-electrode layers.

[0045] The control unit 5 includes a first control unit for independently addressing and controlling each first sub-electrode layer. The first control unit can apply electric field signals of different voltages, frequencies, or timings to any first sub-electrode layer, thereby independently achieving heating or cooling within its corresponding axial segment.

[0046] In an exemplary embodiment, the control unit 5 includes a second control unit for synchronously controlling the energizing state of multiple first sub-electrode layers.

[0047] The control unit 5 also includes a second control unit, which can be used to synchronously or in conjunction with multiple first sub-electrode layers using preset logic or unified instructions. For example, when it is necessary to raise or lower the overall temperature of the entire lifting area, all first sub-electrode layers can be quickly and synchronously triggered to enter the same working state, ensuring the uniformity and consistency of the global thermal field change.

[0048] It should be noted that the control unit 5 may only include the first control unit. In this mode, each first sub-electrode layer has independent addressing and control capabilities. This is suitable for growth processes where the thermal field exhibits significant gradient changes along the axial direction or requires localized fine-tuning thermal compensation, and is particularly beneficial for handling critical stages sensitive to axial thermal distribution, such as dynamic adjustment of the solid-liquid interface and crystal neck narrowing. The control unit 5 may also only include the second control unit. In this mode, multiple first sub-electrode layers are driven by unified control commands, and their operating states remain synchronized. This is suitable for crystal constant-diameter growth stages with high requirements for thermal field uniformity and stable axial gradients, simplifying the complexity of the control system and improving the response speed and consistency of global thermal field control. The control unit 5 may also simultaneously include both the first and second control units. In this integrated mode, it can dynamically switch between independent control and collaborative control or operate in a hybrid manner according to process needs. For example, synchronous control can be used in the main constant-diameter growth stage to maintain overall thermal field stability, while independent control can be automatically activated to quickly compensate the corresponding sub-electrode layer when a local temperature anomaly is detected. This configuration combines control flexibility and system efficiency, and is suitable for advanced crystal growth processes with multi-stage and multi-objective optimization.

[0049] In an exemplary embodiment, the second control unit is further configured to group and control multiple first sub-electrode layers. Based on the thermal field distribution characteristics or process stage requirements during crystal growth, it can divide several axially adjacent or non-adjacent sub-electrode layers into different control groups and implement differentiated or coordinated electric field control strategies for each group. For example, the first sub-electrode layer near the solid-liquid interface can be divided into a first control group, and the first sub-electrode layer far from the solid-liquid interface can be divided into a second control group. For the first control group, high-frequency, small-amplitude adjustments are used to address transient fluctuations, while for the second control group, a stable output is used to maintain the overall thermal environment. Alternatively, the first sub-electrode layers located at different axial positions in the guide tube 1 can be assigned to different control groups. By setting different electric field strengths or duty cycles between each control group, a preset axial temperature gradient curve can be constructed and maintained within the crystal rod pulling region.

[0050] In an exemplary embodiment, the width of the first sub-electrode layer in the axial direction of the guide tube 1 can be 60-80 mm, but is not limited thereto.

[0051] In an exemplary embodiment, an insulating portion 9 is provided between adjacent first sub-electrode layers.

[0052] In an exemplary embodiment, the width of the insulating portion 9 in the axial direction of the guide tube 1 is 10-16 mm, that is, the spacing between adjacent first sub-electrode layers is 10-16 mm, but it is not limited thereto.

[0053] In an exemplary embodiment, at least one first sub-electrode layer includes a plurality of second sub-electrode layers in the circumferential direction of the flow guide tube 1.

[0054] By employing the above technical solution, at least one first sub-electrode layer includes multiple second sub-electrode layers in the circumferential direction of the guide tube 1. Differentiated thermal adjustment can be performed in different circumferential directions at preset axial positions.

[0055] In an exemplary embodiment, the control unit 5 further includes a third control unit for independently controlling the energizing state of the plurality of second sub-electrode layers.

[0056] The control unit 5 is equipped with a third control unit, which is used to independently control the energizing state of each second sub-electrode layer within the same axial segment. This enables asymmetric adjustment of the temperature distribution along the crystal cross-section, compensating for circumferential thermal field inhomogeneities caused by gas flow, heater layout, or thermal shield openings, and optimizing the radial growth quality and crystallization symmetry of the crystal.

[0057] In this embodiment, by partitioning the electrode layer 7 axially and circumferentially, and combining it with independently controllable multi-channel drive, high-resolution, dynamic, and programmable control of the single-crystal furnace thermal field in three-dimensional space is achieved, significantly improving the adaptability to complex thermal environments. Axial and circumferential control modes can be flexibly configured according to the specific thermal field requirements of different crystal materials, diameters, and growth stages, supporting diverse control strategies from globally uniform heating to locally precise compensation.

[0058] In an exemplary embodiment, in the axial direction of the guide tube 1, the inner wall of the guide tube 1 includes a first portion near the top of the furnace body and a second portion away from the top of the furnace body, and the electric heating film 3 is disposed on the inner wall of the guide tube 1 and at least covers the second portion.

[0059] By adopting the above technical solution, the thermal field adjustment device is concentrated in areas that have a more direct impact on crystal growth, especially near the solid-liquid interface and the high-temperature zone in the lower half of the guide tube 1. This design can effectively provide dynamic compensation for areas where the radiation and convection effects of the main heat sources are significant, thereby optimizing the longitudinal thermal environment for crystal growth.

[0060] To further improve the uniformity and controllability of the overall thermal field, the coverage of the electrothermal film 3 can also be extended upward to the first part, forming a complete or segmented coverage of the inner wall of the guide tube 1, thereby constructing a fully adjustable thermal field from the thermal screen area to the growth interface.

[0061] In an exemplary embodiment, an insulating layer 6 is provided between the electrothermal film 3 and the flow guide tube 1.

[0062] The insulating layer 6 can be made of high-temperature ceramic film or yttrium oxide, etc., to ensure that it can effectively block the current path between the electrode layer 7 and the guide tube 1, prevent leakage or short circuit, and ensure the long-term stable and safe operation of the system.

[0063] In an exemplary embodiment, a protective layer 8 is provided on the side of the electrode layer 7 away from the flow guide tube 1.

[0064] The protective layer 8 provides a mechanical barrier for the underlying electrode layer 7 and the electrothermal film 3, preventing damage caused by airflow erosion, physical contact, or thermal shock.

[0065] For example, the protective layer 8 can be made of silicon carbide. Silicon carbide maintains structural stability and mechanical strength at high temperatures (typically withstanding temperatures above 1600°C for extended periods), without softening, deformation, or significant evaporation, making it suitable for the high-temperature operating environment near the heat source in single-crystal furnaces. In the atmosphere of molten silicon volatilization and inert gas environments, silicon carbide exhibits good chemical stability, is not easily reacted with common furnace materials (such as SiO, Si, etc.), and can effectively isolate the electrode layer 7, preventing contamination from spreading to the crystal growth area. Furthermore, silicon carbide has high thermal conductivity (approximately 120-200 W / m·K at room temperature), which facilitates rapid heat transfer within the protective layer 8, reduces localized overheating, promotes uniform thermal field distribution, and does not affect the response speed of the electrothermal film 3.

[0066] In an exemplary embodiment, the electrode layer 7 and the protective layer 8 can be integrated into one unit. That is, the electrode layer 7 can be directly fabricated from a material that combines high conductivity and high environmental stability, so that it can perform its conductive function while also effectively protecting the underlying electrothermal film 3 and its own structure. For example, the electrode layer 7 can be made of platinum, molybdenum, or a high-temperature resistant ceramic composite material.

[0067] By eliminating the separate protective layer 8 structure, the number of interfaces is reduced, thereby lowering the risk of failure due to interlayer thermal expansion mismatch or interface degradation, and improving the overall structural strength and long-term operational reliability of the device.

[0068] For example, the side of the protective layer 8 away from the electrode layer 7 is a smooth surface, which facilitates cleaning, prevents the accumulation of impurities, and ensures the uniformity of the electrothermal film 3 and the electric field.

[0069] In an exemplary embodiment, the control unit 5 is configured to apply a DC voltage to the electrode layer 7, or the control unit 5 is configured to adjust the duty cycle of the target voltage applied to the electrode layer 7 within a fixed period by means of pulse width modulation, so as to control the electric field strength applied to the electrothermal film 3.

[0070] The control unit 5 can apply a constant DC voltage to the electrode layer 7. By adjusting the magnitude of this DC voltage, the static electric field intensity acting on the electrothermal film 3 can be directly controlled. This mode is suitable for scenarios that require stable and continuous heat output, such as basic heating of the thermal field or process stages that maintain a constant temperature gradient for a long time.

[0071] The control unit 5 can also indirectly achieve dynamic adjustment of the equivalent electric field strength on the electrothermal film 3 by adjusting the duty cycle (i.e., the ratio of conduction time to total cycle time) of the target voltage pulse applied to the electrode layer 7 within a fixed period. By changing the duty cycle, the average power output to the electrode layer 7 can be continuously and linearly adjusted, thereby finely controlling the heat release / absorption intensity of the electrothermal film 3.

[0072] In an exemplary embodiment, the thermal field adjustment device further includes a temperature detection structure for real-time monitoring of the temperature distribution in key areas of the furnace body and feeding the temperature signal back to the control unit 5 to form a closed-loop control system.

[0073] For example, the temperature detection structure may include a temperature sensor disposed inside the furnace. The position and number of the temperature sensor can be set according to actual needs, such as being disposed at different axial positions of the crystal rod, near the solid-liquid interface, etc.

[0074] For example, the temperature sensor may be a non-contact infrared temperature sensor.

[0075] In an exemplary embodiment, the thermal field adjustment device further includes a crystal rod diameter measuring structure for measuring the diameter of the crystal rod in real time and transmitting a signal to the control unit 5. The control unit 5 is configured to increase the electric field strength when the signal indicates that the measured diameter of the crystal rod is less than a preset diameter, and to decrease the electric field strength when the signal indicates that the measured diameter of the crystal rod is greater than the preset diameter.

[0076] The thermal field adjustment device also includes a crystal rod diameter measurement structure for real-time monitoring of the diameter change of the crystal rod during growth and transmitting the measurement signal to the control unit 5. The control unit 5 dynamically adjusts the electric field intensity applied to the electrode layer 7 based on the deviation between the received diameter signal and the preset diameter target value, achieving feedback control of the thermal field. For example, when the measured diameter is smaller than the preset diameter: the control unit 5 increases the electric field intensity applied to the electrode layer 7 (e.g., by increasing the DC voltage amplitude or increasing the pulse width modulation duty cycle), driving the electrothermal film 3 to enhance heat release, thereby raising the temperature near the solid-liquid interface, increasing the melt undercooling, promoting radial crystal growth, and gradually restoring the diameter to the target range. When the measured diameter is larger than the preset diameter: the control unit 5 weakens the electric field intensity applied to the electrode layer 7 (e.g., by reducing the DC voltage or decreasing the pulse width modulation duty cycle), causing the electrothermal film 3 to switch to heat absorption or reduced heat release, lowering the interface temperature, reducing the melt undercooling, suppressing radial crystal growth, and gradually shrinking the diameter to the preset target.

[0077] For example, the crystal rod diameter measuring structure may include a reflective or through-beam laser sensor, and the crystal rod diameter measuring structure may also include an image acquisition unit, which acquires an image of the crystal rod and calculates the diameter of the crystal rod in real time using an image processing algorithm.

[0078] In an exemplary embodiment, the thermal field adjustment device further includes a solid-liquid interface morphology monitoring structure for acquiring solid-liquid interface morphology information in real time and transmitting a signal to the control unit 5. The control unit 5 is configured to enhance the electric field strength when the signal indicates that the solid-liquid interface is convex to the crystal rod.

[0079] When the solid-liquid interface is convex towards the crystal rod, i.e., the interface is convex, the temperature in the center of the crystal rod is relatively high and the temperature at the edge is low. In this case, it is necessary to increase the temperature at the edge of the crystal rod to obtain a flat solid-liquid interface. Under this control strategy, the heat released by the electrothermal film 3 increases, which raises the temperature of the edge region of the crystal rod, thereby reducing the temperature difference between it and the center region. This adjustment helps to reduce the supercooling gradient between the edge and the center of the crystal rod, so that the growth rate at the edge is relatively slowed down and the growth rate at the center is relatively increased. This, in turn, promotes the transformation of the solid-liquid interface from convex to flat or moderately concave, optimizes the thermodynamic conditions at the crystal growth front, and improves the internal quality and radial uniformity of the crystal.

[0080] For example, the solid-liquid interface monitoring structure includes an image acquisition unit, which acquires an image of the solid-liquid interface and obtains the morphological information of the solid-liquid interface in real time through an image processing algorithm.

[0081] For example, the electrothermal film 3 can be achieved using a variety of electrothermal material systems to achieve efficient thermal regulation. Based on the fundamental principle of the electrothermal effect, material systems with different structures and properties exhibit different electrothermal properties. Current research focuses on materials such as relaxor ferroelectric ceramics, polymer composite electrothermal films, and superlattice films, all of which exhibit excellent electrothermal response characteristics.

[0082] For example, the antiferroelectric ceramic material (Pb0.97La0.02)(Zr0.95Ti0.05)1₊yO3 (y=-0.01, thickness 0.8mm) can achieve a temperature change as high as 12.45K under an applied electric field of 50V / μm. Other studies have optimized modified barium titanate-based ferroelectric ceramics, achieving significant temperature changes of 1.07K and 2.19K at lower electric fields of 8V / μm and 18V / μm, respectively. Furthermore, Zhang Tiandong et al. achieved good electrothermal performance and temperature stability over a wide temperature range by designing a multilayer thin film structure with gradually varying composition. Other research shows that by designing thin films with non-uniform thickness, differentiated thermal responses can be generated in different regions, thereby achieving controllable adjustment of the spatial distribution of the thermal field. The electrothermal thin film material 3 of this device can be selected from the above material systems or optimized through composite processes according to specific process requirements to achieve dynamic control of the thermal field with high response, high efficiency, and long lifespan. For example, the material of the electrothermal film 3 in this embodiment can be at least one of antiferroelectric ceramic material or modified barium titanate-based ferroelectric ceramic. The thickness of the electrothermal film 3 can be designed as a uniform structure or a non-uniform structure according to the requirements of thermal field control. When the electrothermal film 3 adopts a non-uniform structure, the thickness of the electrothermal film 3 can be set in a gradient in the axial direction of the guide tube 1, and the thickness of the electrothermal film 3 gradually increases along the direction close to the solid-liquid interface.

[0083] For example, in order to better control the morphology of the solid-liquid interface, the electrothermal film 3 extends in the axial direction of the guide tube 1 and covers the bottom surface of the guide tube 1, that is, the end face facing the solid-liquid interface. An electrode layer 7 is also covered on the electrothermal film 3 located on the bottom surface of the guide tube 1.

[0084] This disclosure also provides a single crystal furnace, including a furnace body and the aforementioned thermal field regulating device disposed within the furnace body. The thermal field regulating device is disposed between the inner wall of the guide tube 1 and the crystal rod pulling region. Along the radial direction of the guide tube 1, the thermal field regulating device includes a stacked electrothermal thin film 3 and an electrode layer 7. The thermal field regulating device further includes a control unit 5 for controlling the energizing state of the electrode layer 7 to control the electric field strength of the electrothermal thin film 3. The thermal field regulating device also includes a temperature detection structure, a crystal rod diameter measurement structure, and a solid-liquid interface morphology monitoring structure.

[0085] In this embodiment, by acquiring solid-liquid interface morphology information in real time, when the interface shape deviates from the preset target (such as excessive convexity, asymmetry, or local distortion), the control unit 5 automatically identifies the axial and circumferential electrode layer 7 partitions corresponding to the abnormal interface region and applies directional control signals to these partitions: if local growth needs to be promoted, the corresponding partition's electrothermal film 3 is driven to release heat, increasing the temperature of the region and reducing supercooling, causing the interface to advance locally; if local growth needs to be suppressed, the corresponding partition is driven to absorb heat, decreasing the temperature of the region and increasing supercooling, causing the interface to retract locally. Through this rapid thermal modulation of partitions, the interface shape can be dynamically corrected, making it stably approach the ideal target morphology, thereby improving crystal uniformity and defect distribution.

[0086] In this embodiment, the signal from the diameter measurement sensor is connected to the control unit 5 to form a fast response loop: for high-frequency, small-amplitude fluctuations in diameter (such as those caused by melt convection, mechanical vibration, etc.), the electric field strength of the corresponding region's electrothermal film 3 is adjusted to perform millisecond-level rapid thermal compensation, thereby achieving immediate suppression of diameter fluctuations; the main heater (such as the side or bottom heater) is freed from the high-frequency adjustment task and focuses on the macroscopic adjustment of low-frequency, trend-based changes in diameter, thereby improving the overall system's control stability and energy efficiency ratio.

[0087] It should be noted that when there is a conflict between solid-liquid interface control and crystal rod diameter control, the morphology of the solid-liquid interface can be prioritized, and the crystal rod diameter can be adjusted by controlling the Czochralski pulling speed. For example, when the solid-liquid interface has excessive convexity and requires local cooling to flatten it, it may simultaneously be detected that the diameter is too small and requires heating to promote growth; the two thermal control needs are opposite. In this case, maintaining the solid-liquid interface at the target morphology can be prioritized. This is because the shape of the solid-liquid interface directly affects the crystallization quality, defect distribution, and radial uniformity, and is a key factor determining crystal performance.

[0088] This disclosure also provides a thermal field conditioning method applied to the above-described thermal field conditioning device, the thermal field conditioning method comprising:

[0089] Measure the diameter of the crystal rod to obtain the real-time diameter signal of the crystal rod during the growth process;

[0090] When the measured diameter of the crystal rod is smaller than the preset diameter, the electric field strength applied to the electrothermal film 3 is increased to increase the heat release of the electrothermal film 3. When the measured diameter of the crystal rod is larger than the preset diameter, the electric field strength applied to the electrothermal film 3 is decreased to increase the heat absorption of the electrothermal film 3.

[0091] For example, the thermal field conditioning method further includes:

[0092] Real-time acquisition of solid-liquid interface morphology information;

[0093] The electric field strength of the electrothermal film 3 is dynamically adjusted based on the difference between the solid-liquid interface morphology information and the preset standard morphology.

[0094] When a solid-liquid interface is detected to be convex toward the crystal rod (central convexity), the electric field intensity in the corresponding orientation (especially the edge region) is increased, which increases the heat release of the electrothermal film 3 in that region, thereby raising the edge temperature, reducing the difference in supercooling between the center and the edge, and promoting the interface to become flatter.

[0095] When a concave solid-liquid interface is detected towards the melt (central depression), the electric field strength in the edge region is weakened or the corresponding central region is strengthened to drive the thin film to absorb or selectively release heat, thereby adjusting the heat flow distribution and restoring the interface to its standard morphology.

[0096] Furthermore, embodiments of this disclosure provide an electronic device including a memory, a processor, and one or more programs stored in the memory and executable on the processor, wherein when the one or more programs are executed by the processor, the electronic device performs the thermal field conditioning method as described above.

[0097] In one embodiment, this disclosure also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0098] The aforementioned computer-readable storage medium, since the computer program stored in its memory is executed by the processor to implement the steps in the above-described method embodiments, can similarly bring about the beneficial effects of the above-described silicon wafer placement and removal method, which will not be elaborated here.

[0099] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0100] The following points need to be explained:

[0101] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0102] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0103] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0104] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A thermal field adjusting device applied to a single crystal furnace, the single crystal furnace comprising a furnace body, a flow guide cylinder being arranged in the furnace body, and a center of the flow guide cylinder being arranged as a crystal bar pulling area, characterized in that, the thermal field adjusting device is arranged between an inner side wall of the flow guide cylinder and the crystal bar pulling area, the thermal field adjusting device comprising: an electrothermal film and an electrode layer being arranged in a radial direction of the flow guide cylinder in a stacked manner, and a control unit being arranged outside the furnace body; the control unit is configured to adjust an intensity of an electric field applied to the electrothermal film by controlling an energization state of the electrode layer, so that the electrothermal film is switched between a heat absorption state and a heat release state. In an axial direction of the flow guide cylinder, the electrode layer comprises a plurality of first sub-electrode layers being arranged in a spaced manner. The control unit comprises a first control unit for independently controlling the energization state of the plurality of first sub-electrode layers.

2. The thermal field adjusting device according to claim 1, characterized by The control unit comprises a second control unit for synchronously controlling the energization state of the plurality of first sub-electrode layers.

3. The thermal field adjusting device according to claim 2, characterized in that At least one of the first sub-electrode layers comprises a plurality of second sub-electrode layers in a circumferential direction of the flow guide cylinder.

4. The thermal field adjusting device according to claim 2 or 3, characterized by 6.The thermal field adjusting device according to claim 5, characterized in that, the control unit further comprises a third control unit for independently controlling the energization state of the plurality of second sub-electrode layers.

5. The thermal field adjusting device according to claim 4, characterized in that An insulating part is arranged between adjacent first sub-electrode layers. In the axial direction of the flow guide cylinder, the inner side wall of the flow guide cylinder comprises a first part close to a top of the furnace body and a second part away from the top of the furnace body, the electrothermal film is arranged on the inner side wall of the flow guide cylinder and covers at least the second part. An insulating layer is arranged between the electrothermal film and the flow guide cylinder.

7. The thermal field adjusting device according to claim 2, wherein A protective layer is arranged on a side of the electrode layer away from the flow guide cylinder.

8. The thermal field adjusting device according to claim 1, wherein The control unit is configured to apply a direct current voltage to the electrode layer, or the control unit is configured to adjust a duty cycle of a target voltage applied to the electrode layer in a fixed period by a pulse width modulation mode, so as to control the intensity of the electric field applied to the electrothermal film.

9. The thermal field adjusting device according to claim 8, characterized in that Further comprising a crystal bar diameter measuring structure for measuring a diameter of the crystal bar in real time and transmitting a signal to the control unit, the control unit being configured to increase the intensity of the electric field when the signal is that the measured diameter of the crystal bar is less than a preset diameter, and to decrease the intensity of the electric field when the signal is that the measured diameter of the crystal bar is greater than the preset diameter.

10. The thermal field adjusting device according to claim 8, wherein The single crystal furnace comprises the furnace body and the thermal field adjusting device according to any one of claims 1-12.

11. The thermal field adjusting device of claim 1, wherein The thermal field adjusting method comprises:

12. The thermal field adjusting device according to claim 11, wherein measuring a diameter of the crystal bar; 13. A single crystal furnace characterized by comprising: when the measured diameter of the crystal bar is less than a preset diameter, increasing the intensity of the electric field applied to the electrothermal film to increase a heat release amount of the electrothermal film, and when the measured diameter of the crystal bar is greater than the preset diameter, decreasing the intensity of the electric field applied to the electrothermal film to increase a heat absorption amount of the electrothermal film.

14. A method of thermal field adjustment, applied to the thermal field adjustment device according to any one of claims 1-12, characterized in that, ​ ​ ​

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