Heater for single crystal pulling furnace and single crystal pulling furnace

Abstract

A heater for a single crystal furnace and the single crystal furnace thereof. The heater includes: multiple heater units, which are assembled to form a cylindrical heating element; multiple electrode pins, with adjacent heater units physically connected through one electrode pin, and each heater unit electrically connected to two electrode pins at both ends, wherein the number of electrode pins is an integer multiple of 3, and the integer is greater than or equal to 2; the multiple electrode pins are electrically connected to a three-phase AC power supply. The heater of this invention, by electrically connecting to an AC power supply through electrode pins and assembling multiple heater units into a heating element, improves the power efficiency of the power supply and reduces the material and processing costs of the heater.

Description

[Technical Field]

[0001] This application relates to the field of Czochralski single crystal furnace technology, and more specifically to a heater for a single crystal furnace and a single crystal furnace. [Previous Technology]

[0002] Single-crystal silicon is one of the main substrate materials in semiconductor manufacturing, and the Czochralski method is the most important growth and preparation method for single-crystal silicon. The heater is one of the main components of the Czochralski single-crystal silicon growth thermal field system, and its main function is to convert electrical energy into heat energy to maintain the required temperature and temperature distribution of the thermal field system. In addition, the single-crystal silicon thermal field also includes components such as heat shields, graphite crucibles, crucible trays, insulation cylinders, and insulation felt.

[0003] In the Czochralski method for growing single-crystal silicon, polycrystalline silicon raw material is first placed in a quartz crucible and melted at a temperature above 1420℃. After the temperature stabilizes at the target temperature, a single-crystal silicon seed crystal with a determined crystal orientation is fused to the melt, and then pulled into a crystal. The growth process then involves shoulder formation, shoulder rotation, equal diameter shaping, tailing, and cooling to complete the single-crystal silicon growth. The entire process is completed within a single-crystal furnace. It is important to note that disturbances during the single-crystal silicon growth process can reduce the stability of the crystal growth system. Conventional single-crystal furnaces use a two-electrode DC power supply to power the heater, which requires converting AC to DC. This conversion has low efficiency, resulting in power loss. Furthermore, the high operating voltage makes the heater susceptible to arc discharge between itself and surrounding components, potentially leading to heater failure and an emergency shutdown. Additionally, the integrated processing of traditional DC heaters is difficult, requires high-quality materials, and incurs high material and processing costs. [Summary of the Invention]

[0004] 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 section. The Summary of the Invention section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] This application is made to solve the above problems. According to one aspect of this application, a heater for a single crystal furnace is provided, comprising: a plurality of heater units, wherein the plurality of heater units are spliced ​​to form a cylindrical heating element; a plurality of electrode pins, wherein two adjacent heater units are physically connected through one electrode pin, and two electrode pins are electrically connected to both ends of each heater unit, and the number of electrode pins is an integer multiple of 3, wherein the integer is greater than or equal to 2; and the plurality of electrode pins are respectively electrically connected to a three-phase alternating current power supply.

[0006] In one embodiment of this application, the range of the integer is 2-4.

[0007] In one embodiment of this application, the plurality of electrode pins are symmetrically distributed about the central axis of the cylindrical heating element.

[0008] In one embodiment of this application, two adjacent electrode pins in the axial direction are respectively connected to three-phase alternating current of different phases.

[0009] In one embodiment of this application, the inner circumferential surface of the cylindrical heating element is evenly distributed at equal intervals.

[0010] In one embodiment of this application, the electrode pin is located at the bottom of the inner surface of the cylindrical heating element. When the heater is placed in the single crystal furnace, the bottom is the end away from the raw material melt in the single crystal furnace.

[0011] In one embodiment of this application, a gap is provided between two adjacent heater units, and in the axial direction, each gap is spaced a predetermined distance from the corresponding electrode pin.

[0012] In one embodiment of this application, each heater unit is further provided with at least one cutout, the cutout extending along the axial direction of the cylindrical heating element.

[0013] In one embodiment of this application, the material of the heater unit includes graphite.

[0014] In one embodiment of this application, the height of the heater unit is in the range of 50 mm to 500 mm.

[0015] According to another aspect of this application, a single crystal furnace is provided, the single crystal furnace comprising: a furnace body having a accommodating cavity; a crucible disposed in the accommodating cavity for holding the raw material melt for making a single crystal rod; and the aforementioned heater disposed around the crucible, wherein the cavity within the cylindrical heating body serves as the core thermal field region and growth channel for the growth of the single crystal rod.

[0016] In one embodiment of this application, the heater has one end with the electrode pins located away from the crucible.

[0017] The heater and single crystal furnace of this application are connected to a three-phase AC power supply through multiple electrode pins, and multiple heater units are spliced ​​together to form a heater heating element. This reduces the resistance between two adjacent electrodes, thereby making the heater input operating voltage lower, increasing the safe distance between the heater and surrounding components, reducing the risk of arc discharge present in traditional heaters, and thus reducing the risk of emergency shutdown accidents caused by heater failure. Since the heating element of this application is spliced ​​together from multiple heater units, it is easier to process than a traditional DC heater that is processed as a single piece, reducing the material cost and processing cost of the heater. In addition, the heater of this application uses three-phase AC power, which improves the power efficiency of the power supply compared to DC power.

Implementation Method

[0019] Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art to which this invention pertains that the invention may be practiced without one or more of these details. In other instances, certain technical features commonly known in the art have not been described in order to avoid confusion with the invention.

[0020] It should be understood that the present invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which this pertains. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0021] 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 may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, 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., may be used to describe various elements, elements, areas, layers, and / or portions, these elements, elements, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, element, area, layer, or portion from another element, element, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, element, area, layer, or portion discussed below may be referred to as a second element, element, area, layer, or portion.

[0022] Spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., may be used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relations, terms, etc., are intended to also include different orientations of elements in use and operation. For example, if an element in the figure is flipped, then an element or feature described as "below" or "under" or "below" other elements will be oriented "above" other elements or features. Thus, the exemplary terms "below" and "below" can include both upper and lower orientations. Elements may be oriented in other ways (rotated 90 degrees or other orientations) and the spatial descriptions used herein will be interpreted accordingly.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms as defined in commonly used dictionaries shall be construed as having a meaning consistent with their meaning in the relevant field and / or the context of this specification, and shall not be interpreted in an ideal or overly formal sense, unless expressly defined herein.

[0024] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art to which this application pertains without progressive effort should fall within the protection scope of the present invention.

[0025] First, the heater used to implement the embodiments of the present invention will be described with reference to Figures 1 and 5. Figure 1 shows a top view of the heater according to an embodiment of the present application. Figure 2A shows a front view of the heater according to an embodiment of the present application. Figure 2B shows a structural schematic diagram of the heater unit of the heater according to an embodiment of the present application; Figure 3A shows a schematic diagram of the heater according to one embodiment of the present application; Figure 3B shows a schematic diagram of the heater according to another embodiment of the present application; Figure 4 shows a circuit schematic diagram of a three-phase AC power supply according to an embodiment of the present application; Figure 5 shows a circuit connection schematic diagram of the heater according to an embodiment of the present application.

[0026] The heater according to an embodiment of this application is used to provide heat energy in a single crystal furnace, and includes: a plurality of heater units 11 and a plurality of electrode pins 12. The plurality of heater units 11 are spliced ​​to form a cylindrical heating element, and two adjacent heater units 11 are physically connected through an electrode pin 12. Each heater unit 11 is electrically connected to two electrode pins 12 at both ends, and the number of electrode pins 12 is an integer multiple of 3, wherein the integer is greater than or equal to 2. The plurality of electrode pins 12 are electrically connected to a three-phase AC power supply.

[0027] The heater and single crystal furnace of this application are connected to a three-phase AC power supply through multiple electrode pins, and multiple heater units are spliced ​​together to form a heater heating element. This reduces the resistance between two adjacent electrodes, thereby making the heater input operating voltage lower, increasing the safe distance between the heater and surrounding components, and reducing the risk of arc discharge present in traditional heaters. Since the heating element of this application is composed of multiple heater units spliced ​​together, it is easier to process than a traditional DC heater that is processed in one piece, reducing the material cost and processing cost of the heater. In addition, the heater of this application uses three-phase AC power, which improves the power efficiency of the power supply compared to DC power.

[0028] In one embodiment, the material of the heater unit 11 includes graphite or other suitable conductive materials. The heater unit 11 is part of the heating element of the heater and needs to provide a stable and continuous energy supply to the single crystal furnace. When the heater fails, the single crystal furnace loses its only heat source, leading to a forced shutdown. Therefore, the material of the heater unit 11 is crucial to the heater. Graphite has excellent electrical conductivity, is generally cheaper than metals, and is very easy to use. Therefore, the material of the heater unit 11 in this embodiment includes graphite or other suitable conductive materials.

[0029] The heater adopts a multi-stage structure composed of multiple heater units spliced ​​together. There is a heater unit between two electrode pins. As the number of heater units increases, the volume of the heater unit will decrease accordingly, and its corresponding resistance will also decrease, thereby reducing the resistance between adjacent electrodes. Therefore, a lower heater input voltage can be used. Optionally, the heater input voltage can be 12-60V, and more preferably, the input voltage can be a safe voltage of 20-36V. Compared with the DC power supply voltage of approximately 30-60V, the input voltage of the heater in this application can be lower.

[0030] Because a lower heater input voltage can be used, the safe distance between the heater and surrounding components can be increased, reducing the arc risk present in traditional heaters. Arc risk refers to the phenomenon in high-voltage electrical equipment where, when the potential difference between two conductors reaches a certain level, air molecules are ionized, forming plasma and causing a discharge. This phenomenon can cause serious consequences such as equipment damage or fire. Therefore, the heater in this application is composed of multiple heater units connected together. The heater is electrically connected to multiple sets of three-phase AC power supplies through multiple electrode pins 12. Lowering the heater's input voltage reduces the probability of this risk occurring.

[0031] In some embodiments, a heater unit 11 may include a heater subunit, or in some embodiments, a heater unit 11 may include at least two heater subunits connected to form a heater unit 11, for example, at least two heater subunits arranged and spliced ​​in the axial direction, or arranged and spliced ​​in the circumferential direction. Dividing it into at least two heater subunits makes it easier to process and reduces processing costs. In one embodiment, the cross-section of the heater unit 11 in the direction perpendicular to the heater axial direction is an arc surface.

[0032] In one embodiment of this application, as shown in FIG2A, two adjacent heater units 11 are physically connected through an electrode pin 12. For example, multiple heater units 11 are spliced ​​together to form a cylindrical heating element. Two adjacent heater units 11 are physically connected through an electrode pin 12. More specifically, the two ends of an electrode pin 12 are connected to a heater unit 11 through, for example, a fastener 14, thereby realizing the physical connection of two heater units 11. For example, as shown in FIG2B, each heater unit 11 is provided with a connection hole 141, and the electrode pin 12 is provided with a connection hole (not shown). For example, at least two connection holes are provided. Part of the connection holes in the at least two connection holes are used to correspond and match with the connection hole in one of the two adjacent heater units 11, and the other part of the connection holes is used to correspond and match with the connection holes in the two adjacent heater units 11. The fastener can be inserted into the connection hole 141 and the connection hole of the electrode pin 12, thereby realizing the physical connection of two heater units 11 using an electrode pin 12. The two ends of each heater unit 11 are electrically connected to two electrode pins 12 respectively. Electrode pins 12, connected to a power source, supply current to the heater, which converts electrical energy into heat energy. The cylindrical heating element, composed of heater units 11, generates heat, providing the system with the required heat. Compared to heaters manufactured as a single unit, this significantly reduces material and manufacturing costs. In one embodiment, the number of heater units 11 is equal to the number of electrodes.

[0033] In some examples, without considering the difficulty of processing, multiple heater units are integrally formed, and the electrode pins can be connected to the heater units by, for example, fasteners. Or, in other examples, as shown in Figures 3A and 3B, multiple heater units and multiple electrode pins are integrally formed.

[0034] Traditional Czochralski single-crystal silicon furnaces use DC power supplies for heaters, resulting in low power conversion efficiency and high operating voltage. The power supply system employs a modular design and combined structure, consisting of AC input, transformer, rectifier, filter circuit, voltage regulator, and DC output. However, the design of this power supply is typically quite complex. Therefore, the heater in this embodiment uses AC power, which improves the power efficiency. The heater in this application requires connection to a three-phase AC power supply, and the output voltage is low-voltage adjustable. Therefore, the power supply design for the single-crystal furnace is simpler than that of a DC power supply, requiring only transformation and voltage regulation, eliminating the need for rectification and filtering. This reduces the number of electrical components in the entire power supply system, improves the power factor, reduces equipment hardware costs, and lowers energy consumption.

[0035] Three-phase alternating current (AC) is a form of electrical energy transmission, often simply called three-phase electricity. A three-phase AC power source consists of three alternating electromotive forces with the same frequency, equal amplitude, and phases differing by 120°. Actual three-phase AC is generated by a three-phase generator, which has three identical windings evenly distributed with a spatial phase difference of 120°. These three windings are referred to as phase A, phase B, and phase C.

[0036] In one embodiment of this application, the plurality of electrode pins 12 are electrically connected to the three-phase AC power supply. The three phases of industrial power (AC) are connected to the three electrode pins 12 after being transformed and regulated by the AC power supply. Each set of three electrode pins arranged sequentially along the inner surface of the cylindrical heating element is connected to one phase of the three-phase AC power supply.

[0037] Exemplarily, the number of electrode pins 12 is an integer multiple of 3, where the integer is greater than or equal to 2. In one embodiment, the integer ranges from 2 to 4. For example, as shown in FIG3A, the number of electrode pins 12 can be 6, and as shown in FIG3B, the number of electrode pins 12 can be 9. One set of three-phase AC power connects three electrode pins 12, two sets of three-phase AC power connect six electrode pins 12, and three sets of three-phase AC power connect nine electrode pins 12. Although a heater with only one set of three-phase AC power can improve power utilization efficiency, the heater itself will drive the melt flow with the Lorentz force generated in the melt, which is not conducive to the stability of crystal growth. Therefore, in this application, by setting the number of electrode pins 12 to an integer multiple of 3, where the integer is greater than or equal to 2, the heater can be connected to at least two sets of three-phase AC power through the electrode pins 12. Compared with a single set of three-electrode AC power heater, after the number of electrodes increases, the current between the electrodes decreases. According to the principle of electromagnetic induction, the intensity of the electromagnetic field generated decreases, and the Lorentz force applied to the silicon melt decreases. As the number of heater electrodes increases, the influence of alternating current on melt convection is essentially eliminated, achieving results similar to those of direct current heaters and enhancing the stability of crystal growth. In one embodiment, multiple electrode pins 12 are symmetrically distributed about the central axis of the cylindrical heating element. This symmetrical distribution of multiple electrode pins ensures that the Lorentz forces generated by the A-phase and C-phase currents in the melt cancel each other out, without altering the melt's convection structure. Furthermore, the electrode pins themselves are also heating elements. The symmetrical distribution of multiple electrode pins improves the symmetry of the thermal field within the single-crystal furnace, enhancing the stability of crystal growth. Multiple heater units 11 are interconnected via electrode pins 12, and these units are assembled into a cylindrical heating element. The multiple heater units 11 are identical in shape and size, and the multiple electrode pins 12 are evenly distributed at equal intervals along the circumference of the cylindrical heating element. The electrode pins 12 connected to the heater units 11 are symmetrically distributed about the central axis of the cylindrical heating element. The included angle between the two electrode pins 12 is 360 / n, where n is the number of electrode pins 12. The number of electrode pins 12 can be an integer multiple of the number of phases of the AC current, which is greater than or equal to 2. For example, when there are 6 electrode pins 12, the included angle between the two electrode pins 12 is 60°.

[0038] It is worth mentioning that the multiple heater units 11 may also have different sizes, for example, different curvatures.

[0039] In one embodiment, two adjacent electrode pins 12 in the axial direction are respectively connected to three-phase AC power of different phases. As shown in Figure 4, a three-phase AC power supply refers to a power supply that can provide three voltages or currents with the same frequency but different phases, where each power supply is called a phase, namely phase A, phase B, and phase C of the AC power supply. Two adjacent electrode pins 12 in the circumferential direction are respectively connected to three-phase AC power of different phases. For example, one electrode pin 12 is connected to phase A of the three-phase AC power, and an adjacent electrode pin 12 is connected to phase B or phase C of the three-phase AC power. Three adjacent electrode pins 12 in the circumferential direction are respectively connected to phase A, phase B, and phase C of the three-phase AC power.

[0040] In one embodiment, as shown in FIG. 5, the heater includes 6 electrode pins 12 and 6 heater units 11, each heater unit 11 having an included angle of 60°, and the included angle between two adjacent electrode pins 12 being 60°. The heater is connected to two sets of three-phase AC power through the 6 electrode pins 12, which are symmetrically connected to phases A, B, and C of the three-phase AC power. The operating voltage is selected from 12 V to 60 V, for example, 24 V. The experiment is conducted in a 32-inch hot zone, growing a single crystal rod with a diameter of 300 mm. In contrast, a heater using DC power, with an operating voltage of approximately 60 V, undergoes similar heating, melting, crystal pulling, shoulder formation, constant diameter growth, finishing, and cooling steps after the silicon material is loaded into the furnace. The crystal rod is then removed for subsequent processing and analysis. It was found that the crystal growth process is stable with the heater of this application, and no abnormal events related to the crystal rod growth process using a DC power heater were observed. The power consumption per unit of the crystal rod is reduced by approximately 5%.

[0041] In an embodiment of this application, the electrode pin 12 is located at the bottom of the inner surface of the cylindrical heating element. When the heater is placed in a single crystal furnace, the bottom is the end away from the raw material melt in the single crystal furnace. In one embodiment, the bottoms of adjacent heater units 11 are physically connected through the electrode pin 12 at the bottom of the inner surface, and the tops of adjacent heater units 11 are connected through a connector. The heater is placed in a Czochralski single crystal furnace, and the crucible is placed in a cylindrical heating element composed of multiple heater units 11. The heater heats the material in the crucible, and the bottom of the cylindrical heating element is the end away from the raw material melt in the single crystal furnace.

[0042] In the embodiments of this application, a gap 13 is provided between two adjacent heater units 11. In the axial direction, each gap 13 is spaced a predetermined distance from its corresponding electrode pin 12. To ensure the heating effect of the heater, the width of the gap 13 is generally not very large, but also not very small, to prevent dust accumulation and short circuits between heater units. It is usually 6 mm-12 mm, adjusted according to the design of the heater resistance value. The electrode pin 12 is located at the bottom of the heater unit 11, and the gap 13 between two adjacent heater units 11 does not reach the bottom of the heater unit 11 in the radial direction. Therefore, each gap 13 is spaced a predetermined distance from its corresponding electrode pin 12. Optionally, the axial length of the gap 13 is less than the axial height of the heater unit 11.

[0043] As shown in Figure 2B, which is used to show the heater unit 11 in the dashed box of Figures 1 and 5, in the embodiments of this application, each heater unit 11 is further provided with at least one cut 15, which extends axially along the cylindrical heating element. The cut 15 provided in each heater unit 11 extends axially along the cylindrical heating element, wherein the cylindrical heating element has a first end 16 and a second end 17 opposite to the first end 16. The cut 15 extends from the first end 16 to the second end 17, and there is a gap between the cut 15 and the second end 17. Alternatively, the cut 15 may also extend from the second end 17 to the first end 16, and there is a gap between the cut 15 and the first end 16. Specifically, the cut 15 may extend from the bottom to the top of the heater unit 11, and there is a gap between the cut 15 and the top of the heater unit 11; the cut 15 may also extend from the top to the bottom of the heater unit 11, and there is a gap between the cut 15 and the bottom of the heater unit 11. The heater unit 11 is formed into an S-shaped resistor by means of multiple cuts 15, wherein the length of the cuts 15 along the axial direction is less than the height of the heater unit in the axial direction.

[0044] In an embodiment of this application, as shown in FIG2B, the heater unit 11 has a plurality of cuts 15. The plurality of cuts 15 may include at least one first cut and at least one second cut. The first cut and the second cut are alternately arranged circumferentially. The first cut extends from the first end 16 to the second end 17, and the second cut extends from the second end 17 to the first end 16. Alternatively, the second cut extends from the first end 16 to the second end 17, and the first cut extends from the second end 17 to the first end 16. This is not specifically limited. The axial length of the cut 15 is less than the axial height of the heater unit 11.

[0045] In this embodiment, the height of the heater unit 11 ranges from 50 mm to 500 mm. The height of the heater unit 11 refers to the dimension of the heater unit 11 along the axial direction of the cylindrical heating element. Since multiple heater units 11 are spliced ​​together to form a cylindrical heating element, the height of the heater unit 11 determines the height of the heating element, and the height of the heating element determines the height of the heater. The height of the heater can be comparable to the height of the single crystal furnace crucible or can be enlarged or reduced according to the process design.

[0046] Therefore, the heater for a single crystal furnace according to this application is connected to a three-phase AC power supply through multiple electrode pins, and multiple heater units are spliced ​​together to form a heater heating element, which reduces the resistance between two adjacent electrodes, thereby making the heater input operating voltage lower, increasing the safe distance between the heater and surrounding components, and reducing the risk of electric arc present in traditional heaters. Since the heating element of this application is spliced ​​together from multiple heater units, it is easier to process than a traditional DC heater that is processed in one piece, reducing the material cost and processing cost of the heater. Furthermore, the heater of this application uses three-phase AC power, which improves the power efficiency of the power supply compared to DC power.

[0047] The single crystal furnace, heater, and crucible provided according to another aspect of this application are described below with reference to FIG. 6. FIG. 6 shows a schematic structural diagram of a single crystal furnace according to an embodiment of this application. FIG. 7 shows a schematic diagram of a heater and crucible according to an embodiment of this application. As shown in FIG. 6 and FIG. 7, the single crystal furnace includes a furnace body 21, a crucible 22, and a heater 23, wherein: the furnace body 21 has a receiving cavity; the crucible 22 is disposed in the receiving cavity for holding the raw material melt 24 for making a single crystal rod; wherein the crucible 22 may include a quartz crucible 221 and a graphite crucible 222, with the quartz crucible 221 disposed in the graphite crucible 222; the heater 23 mentioned above is disposed around the crucible 22, and the cavity inside the cylindrical heating body serves as the core thermal field space and growth channel for the single crystal rod.

[0048] In one embodiment, the heater 23 has one end with electrode pin 12 away from the crucible 22.

[0049] A local model for single-crystal silicon growth is established, including components such as heater 23, quartz crucible 221, graphite crucible 222, and raw material melt 24. Using the finite element method and Maxwell's equations, the Lorentz force generated in the raw material melt 24 (e.g., silicon melt) under the same power supply frequency (e.g., 50Hz) and the same output power of heater 23 with different electrodes is simulated and calculated.

[0050] The numerical simulation results of the Lorentz force generated by the heaters with six electrode pins (as shown in Figure 3A) and nine electrode pins (as shown in Figure 3B) in the molten silicon under the same heating power conditions (e.g., AC frequency 50Hz) show that the maximum value corresponds to the location of the electrode. As shown in Figure 8A, for the heaters with three electrode pins in the related art, the maximum Lorentz force generated on the melt reaches more than 12 (N / m3); while for the heaters with six electrode pins and nine electrode pins of this application, as shown in Figures 8B and 8C, the maximum Lorentz force generated by the heater with six electrode pins in the molten silicon decreases to about 1.6 (N / m3), and the maximum Lorentz force generated by the heater with nine electrode pins in the molten silicon decreases to about 1 (N / m3), which is 13% and 8% of that of the heater with three electrode pins, respectively. This means that the initial motion force on the molten silicon is significantly reduced.

[0051] Those skilled in the art to which this application pertains can understand the structure and specific operation of each module in the single crystal furnace according to the embodiments of this application by referring to the content described above. For the sake of brevity, it will not be described again here.

[0052] Based on the above description, the heater and single crystal furnace of this application for a single crystal furnace are connected to a three-phase AC power supply through multiple electrode pins, and multiple heater units are spliced ​​together to form a heater heating element, which reduces the resistance between two adjacent electrodes, thereby making the heater input operating voltage lower, increasing the safe distance between the heater and surrounding components, and reducing the risk of arc discharge present in traditional heaters. Since the heating element of this application is spliced ​​together from multiple heater units, it is easier to process than a traditional DC heater that is processed in one piece, reducing the material cost and processing cost of the heater. In addition, the heater of this application uses three-phase AC power, which improves the power efficiency of the power supply compared to DC power.

[0053] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art to which this application pertains without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0054] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, methods, structures, and techniques of ordinary knowledge have not been shown in detail so as not to obscure the understanding of this specification.

[0055] It will be understood by those skilled in the art to which this case pertains that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0056] Furthermore, those skilled in the art to which this application pertains will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claim, any one of the claimed embodiments can be used in any combination.

[0057] The above description is merely a specific embodiment or description of the specific embodiment of this application. The protection scope of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application shall be determined by the protection scope of the claims. [Simplified Explanation of the Diagram]

[0018] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the accompanying drawings, the same reference numerals generally represent the same elements or steps. Figure 1 shows a top view of a heater according to an embodiment of the present application; Figure 2 shows a front view of a heater according to an embodiment of the present application; Figure 3 shows a structural schematic diagram of a heater unit according to an embodiment of the present application; Figure 4 shows a circuit schematic diagram of a three-phase alternating current according to an embodiment of the present application; Figure 5 shows a top view of a heater according to an embodiment of the present application; Figure 6 shows a schematic structural diagram of a single crystal furnace according to an embodiment of the present application; Figure 7 shows a schematic diagram of a heater and crucible combined according to an embodiment of the present application; Figure 8A shows a simulation diagram of the Lorentz force generated in a silicon melt by a heater with 3 simulated electrode pins in the related art; Figure 8B shows a simulation diagram of the Lorentz force generated in a silicon melt by a heater with 6 simulated electrode pins in an embodiment of the present application; Figure 8C shows a simulation diagram of the Lorentz force generated in a silicon melt by a heater with 9 simulated electrode pins in an embodiment of the present application.

Claims

1. A heater for a single crystal furnace, comprising: Multiple heater units, which are spliced ​​together to form a cylindrical heating element; Multiple electrode pins, two adjacent heater units are physically connected through one electrode pin, each heater unit is electrically connected to two electrode pins at both ends, and the number of electrode pins is an integer multiple of 3, where the integer is greater than or equal to 2; and the multiple electrode pins are electrically connected to a three-phase AC power supply.

2. The heater as claimed in claim 1, wherein, The range of the integers is 2-4.

3. The heater as claimed in claim 1, wherein, The plurality of electrode pins are symmetrically distributed about the central axis of the cylindrical heating element.

4. The heater as claimed in claim 1, wherein, Two adjacent electrode pins in the axial direction are respectively connected to three-phase AC power of different phases.

5. The heater as claimed in claim 1, wherein, The cylindrical heating element has evenly spaced distributions on its inner circumferential surface.

6. The heater as claimed in claim 5, wherein, The electrode pins are located at the bottom of the inner surface of the cylindrical heating element. When the heater is placed in the single crystal furnace, the bottom is the end away from the raw material melt in the single crystal furnace.

7. The heater as claimed in claim 1, wherein, A gap is provided between two adjacent heater units, and in the axial direction, each gap is spaced a predetermined distance from the corresponding electrode pin.

8. The heater as claimed in claim 1, wherein, Each of the heater units is also provided with at least one cutout that extends axially along the cylindrical heating element.

9. The heater as claimed in any one of claims 1 to 8, wherein, The heater unit is made of graphite.

10. The heater as claimed in any one of claims 1 to 8, wherein, The height of the heater unit ranges from 50 mm to 500 mm.

11. A single crystal furnace, wherein, The single crystal furnace includes: a furnace body having a accommodating cavity; a crucible disposed in the accommodating cavity for holding the raw material melt for making a single crystal rod; and a heater as claimed in any one of claims 1 to 10, disposed around the crucible, wherein the cavity within the cylindrical heating body serves as the core thermal field space and growth channel for the single crystal rod.

12. The single crystal furnace as claimed in claim 11, wherein, The heater has one end with the electrode pins located away from the crucible.

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