Heater for single crystal furnace and single crystal furnace

Abstract

A heater for a single crystal furnace and the single crystal furnace. The heater comprises: a plurality of heater units, the plurality of heater units being connected to form a cylindrical heating body; and a plurality of electrode pins, two adjacent heater units being physically connected by means of one electrode pin, and two ends of each heater unit being respectively and electrically connected to two electrode pins. The number of the electrode pins is an integer multiple of three, and the integer is greater than or equal to two; and the plurality of electrode pins are respectively and electrically connected to a three-phase alternating current of an alternating current power supply. By electrically connecting the electrode pins to the alternating current power supply, and assembling the plurality of heater units to form the heating body, the power efficiency of the power supply is improved, the operating current is reduced, and the stability of molten silicon is enhanced.

Description

Heater for single crystal furnace and single crystal furnace

[0001] The present application claims priority to the Chinese patent application No. 202410660341.5, filed on May 24, 2024, entitled "Heater for single crystal furnace and single crystal furnace", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of Czochralski furnace, more particularly to a heater for single crystal furnace and single crystal furnace. BACKGROUND

[0003] Monocrystalline silicon is one of the main substrate materials for semiconductor devices, and the Czochralski method is the most important method for the preparation of monocrystalline silicon. The heater is one of the main components of the Czochralski silicon growth thermal field system, and its main function is to convert electrical energy into thermal energy to maintain the temperature and temperature distribution required by the thermal field system. In addition, the monocrystalline silicon thermal field also includes a heat shield, a graphite crucible, a crucible tray, a heat preservation cylinder, a heat preservation felt and other components.

[0004] In the growth process of Czochralski monocrystalline silicon, the polycrystalline silicon raw material is first loaded into a quartz crucible and melted at a temperature above 1420℃. After the temperature is stabilized to the target temperature, the single crystal silicon seed crystal with a determined crystal direction is fused with the melt to initiate crystal growth, and then the process of growing single crystal silicon is completed through the processes of shoulder, shoulder, equal diameter, tail, cooling and other processes. The whole process is completed in a single crystal heating furnace. It should be noted that the disturbance of the single crystal silicon growth process may reduce the stability of the crystal growth system. The conventional single crystal furnace uses a two-electrode direct current power supply to supply power to the heater, which requires converting alternating current into direct current. The power conversion efficiency is low, resulting in power loss, and the working voltage is high, which makes it easy for the heater and the surrounding components to exist "arc" discharge risk, and in severe cases, it can cause the heater to fail and cause an emergency shutdown accident. SUMMARY

[0005] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to attempt to limit the key features and necessary technical features of the claimed technical solutions, nor does it mean to attempt to determine the protection scope of the claimed technical solutions.

[0006] The present application is proposed to solve the above problems. According to one aspect of the present application, a heater for a single crystal furnace is provided, comprising: a plurality of heater units connected to form a cylindrical heating body; a plurality of electrode pins, two adjacent heater units are connected to one electrode pin, each heater unit is electrically connected to two electrode pins at two ends respectively, and the number of electrode pins is an integer multiple of 3, the integer being greater than or equal to 2; and the plurality of electrode pins are respectively used to electrically connect three-phase alternating current of an alternating current power supply.

[0007] In one embodiment of the present application, the integer ranges from 2 to 4.

[0008] In one embodiment of the present application, the plurality of electrode pins are symmetrically distributed about the central axis of the cylindrical heating body.

[0009] In one embodiment of the present application, two electrode pins adjacent in the axial direction correspond to three-phase alternating current of different phases respectively.

[0010] In one embodiment of the present application, the plurality of electrode pins are uniformly distributed at equal intervals along the circumferential direction of the cylindrical heating body.

[0011] In one embodiment of the present application, the electrode pin is located at the bottom of the inner surface of the cylindrical heating body, and when the heater is arranged in the single crystal furnace, the bottom is away from the opening of the crucible in the single crystal furnace.

[0012] In one embodiment of the present application, a gap is provided between two adjacent heater units, and in the axial direction, each gap is spaced apart from the corresponding electrode pin by a predetermined distance.

[0013] In one embodiment of the present application, the length of the gap in the axial direction is less than the height of the heater unit in the axial direction.

[0014] In one embodiment of the present application, at least one aperture is further provided in each heater unit, and the aperture extends along the axial direction of the cylindrical heating body.

[0015] In one embodiment of the present application, the cylindrical heating body has a first end portion and a second end portion opposite to the first end portion, the aperture extends from the first end portion to the second end portion, and there is a gap between the aperture and the second end portion, or the aperture extends from the second end portion to the first end portion, and there is a gap between the aperture and the first end portion.

[0016] In one embodiment of the present application, the heater unit has a plurality of apertures, the plurality of apertures include at least one first aperture and at least one second aperture, the first aperture and the second aperture are alternately arranged along the circumferential direction, the first aperture extends from the first end portion to the second end portion, and the second aperture extends from the second end portion to the first end portion.

[0017] In an embodiment of the present application, the length of the slit in the axial direction is less than the height of the heater unit in the axial direction.

[0018] In an embodiment of the present application, the plurality of heater units are integrally formed; or, the plurality of heater units and the plurality of electrode pins are integrally formed.

[0019] In an embodiment of the present application, the plurality of heater units are spliced to form the cylindrical heating body, and two adjacent heater units are physically connected by one electrode pin.

[0020] In an embodiment of the present application, the electrode pin connects two adjacent heater units by a fastener.

[0021] In an embodiment of the present application, the electrode pin extends in a direction parallel to the axial direction of the cylindrical heating body and away from the cylindrical heating body.

[0022] In an embodiment of the present application, the material of the heater unit comprises graphite.

[0023] In an embodiment of the present application, the height of the heater unit ranges from 50 mm to 500 mm.

[0024] According to another aspect of the present application, a single crystal furnace is provided, comprising: a furnace body having a receiving cavity therein; a crucible arranged in the receiving cavity and used for containing a raw material melt for making a single crystal rod; the above-mentioned heater arranged around the crucible, and the cavity in the cylindrical heating body serving as a core hot field interval and a growth channel for the single crystal rod.

[0025] In an embodiment of the present application, the heater has one end of the electrode pin away from the opening of the crucible.

[0026] The heater for a single crystal furnace and the single crystal furnace of the present application connect three-phase alternating current of an alternating current power supply by a plurality of electrode pins, and connect a plurality of heater units into a heater heating body, thereby reducing the resistance between two adjacent electrodes, so that the input working voltage of the heater is lower, the safety distance of the heater and surrounding components is improved, the risk of "arc" discharge existing in the traditional heater is reduced, and the risk of emergency shutdown accident caused by failure of the heater is reduced. Moreover, the heater of the present application uses three-phase alternating current, which improves the power efficiency of the power supply compared with direct current power supply. BRIEF DESCRIPTION OF DRAWINGS

[0027] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description thereof taken in conjunction with the accompanying drawings, in which:

[0028] FIG. 1 shows a top view of a heater according to an embodiment of the present application;

[0029] FIG. 2A shows a front view of a heater according to an embodiment of the present application;

[0030] FIG. 2B shows a structure view of a heater unit of a heater according to an embodiment of the present application;

[0031] FIG. 3A shows a schematic view of a heater according to an embodiment of the present application;

[0032] FIG. 3B shows a schematic view of a heater according to another embodiment of the present application;

[0033] FIG. 4 shows a circuit diagram of a three-phase alternating current according to an embodiment of the present application;

[0034] FIG. 5 shows a schematic view of a heater circuit connection according to an embodiment of the present application;

[0035] FIG. 6 shows a partial schematic block diagram of a single crystal furnace according to an embodiment of the present application;

[0036] FIG. 7 shows a schematic view of a heater and a crucible combined according to an embodiment of the present application;

[0037] FIG. 8A shows a simulation diagram of a Lorentz force value generated by a heater with 3 electrode pins in a silicon melt in the related art;

[0038] FIG. 8B shows a simulation diagram of a Lorentz force value generated by a heater with 6 electrode pins in a silicon melt according to an embodiment of the present application;

[0039] FIG. 8C shows a simulation diagram of a Lorentz force value generated by a heater with 9 electrode pins in a silicon melt according to an embodiment of the present application.

[0040] Reference numerals: 11 heater unit, 12 electrode pin, 13 gap, 14 fastener, 15 gap, 16 first end portion 16, second end portion 17. DETAILED DESCRIPTION

[0041] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present application. However, it will be apparent to one of skill in the art upon

[0042] It should be understood that the present application can be practiced with the elements in different forms and should not be limited to the embodiments set forth. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions can be exaggerated for clarity. Like reference numerals can represent like elements throughout.

[0043] It will be understood that when an element or layer is referred to as being "on" or "adjacent" or "connected" or "coupled" to another element or layer, it can be directly on, adjacent, connected or coupled to the other element or layer or one or more intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on," "directly adjacent," "directly connected" or "directly coupled" to another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0044] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and / or the present specification, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0046] In order to make the objects, technical solutions and advantages of the present application more obvious, the following will describe the example embodiments according to the present application in detail with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present application.

[0047] First, the heater for implementing the embodiments of the present application is described with reference to FIGS. 1 to 5. FIG. 1 shows a top view of a heater according to an embodiment of the present application. FIG. 2A shows a front view of the heater according to an embodiment of the present application. FIG. 2B shows a structure of a heater unit of the heater according to an embodiment of the present application. FIG. 3A shows a schematic diagram of the heater according to an embodiment of the present application. FIG. 3B shows a schematic diagram of the heater according to another embodiment of the present application. FIG. 4 shows a circuit diagram of three-phase alternating current according to an embodiment of the present application. FIG. 5 shows a schematic diagram of a heater circuit connection according to an embodiment of the present application.

[0048] The heater according to an embodiment of the present application, which is used to provide thermal energy for a silicon melt in a single crystal furnace, can include a plurality of heater units 11 and a plurality of electrode pins 12. The plurality of heater units 11 are connected to form a cylindrical heater body, two adjacent heater units 11 are connected to one electrode pin 12, two electrode pins 12 are electrically connected to two ends of each heater unit 11, respectively, and the number of electrode pins 12 is an integer multiple of 3, the integer being greater than or equal to 2, and the plurality of electrode pins 12 are electrically connected to three-phase alternating current of an alternating current power source, respectively.

[0049] The heater for a single crystal furnace and the single crystal furnace of the present application connect three-phase alternating current of an alternating current power source through a plurality of electrode pins, and connect a plurality of heater units to form a heater body, thereby reducing the resistance between two adjacent electrodes, so that the input working voltage of the heater is lower, the safety distance of the heater and surrounding components is improved, the risk of "arc" discharge existing in the conventional heater is reduced, and the heater of the present application uses three-phase alternating current, which improves the power efficiency of the power source compared with a direct current power source.

[0050] In one embodiment, the material of the heater unit 11 comprises graphite or other suitable conductive material. The heater unit 11 is part of the heating body of the heater, and is required to provide stable and continuous energy supply for the single crystal furnace. When the heater fails, the single crystal furnace loses the only heat source, resulting in forced shutdown. Therefore, the material of the heater unit 11 is crucial to the heater. Graphite material has excellent electrical conductivity, generally lower cost than metal, and is very easy to use. Therefore, in the embodiment of the present application, the material of the heater unit 11 comprises graphite.

[0051] The heater adopts a multi-stage structure connected by multiple heater units. Each heater unit is between two adjacent electrode pins. The number of heater units increases, and the volume of the heater unit decreases accordingly. The corresponding resistance of the heater unit also decreases, thereby reducing the resistance between the two adjacent electrodes. Therefore, a lower heater input voltage can be used. Optionally, the heater input voltage can be 12-60V. Preferably, the input voltage can be a safe voltage of 20-36V. Compared with the voltage of the direct current power supply, which is generally 30-60V, the input voltage of the heater of the present application can be lower.

[0052] Since a lower heater input voltage can be used, the safety distance of the heater from the surrounding components can be increased, and the risk of "arcing" existing in traditional heaters can be reduced. The "arcing" risk refers to a phenomenon in high-voltage electrical equipment in which when the potential difference between two conductors reaches a certain level, molecules in the air are ionized to form plasma, thereby causing a discharge phenomenon. This phenomenon can cause damage to the equipment or cause a fire and other serious consequences. Therefore, the heater of the present application is connected by multiple heater units. The heater is electrically connected to multiple groups of three-phase alternating current by multiple electrode pins 12. After the input voltage of the heater is reduced, the probability of this risk is also reduced.

[0053] In some embodiments, one heater unit 11 can comprise one heater subunit, or in some embodiments, one heater unit 11 can comprise at least two heater subunits. The at least two heater subunits are connected to form one heater unit 11, for example, the at least two heater subunits are arranged and connected in the axial direction or arranged and connected in the circumferential direction. By dividing it into at least two heater subunits, it can be easier to process and reduce processing costs. In one embodiment, the cross section of the heater unit 11 perpendicular to the axial direction of the heater is a circular arc surface.

[0054] In one embodiment of the present application, as shown in FIG. 2A, two adjacent heater units 11 are connected by one electrode pin 12, for example, a plurality of heater units 11 are spliced to form a cylindrical heating body, and two adjacent heater units 11 are physically connected by one electrode pin 12. More specifically, the electrode pin 12 is connected to the heater unit 11 by, for example, a fastener 14, thereby achieving physical connection of the two heater units 11. For example, as shown in FIG. 2B, each heater unit 11 is provided with a connecting hole 141, and the electrode pin 12 is provided with connecting holes (not shown), for example, at least two connecting holes, part of the at least two connecting holes are used to correspondingly match the connecting holes in one of the two adjacent heater units 11, and the other part of the at least two connecting holes are used to correspondingly match the connecting holes in the other of the two adjacent heater units 11. The fastener can be arranged in the connecting hole 141 and the connecting hole of the electrode pin 12, thereby achieving physical connection of the two heater units 11 by one electrode pin 12. The two ends (i.e. the two ends in the circumferential direction, which can also be referred to as the two sides in the circumferential direction) of each heater unit 11 are electrically connected to two electrode pins 12, respectively. The electrode pins 12 are connected to the power supply to supply current to the heater, and the heater converts electrical energy into heat energy. The cylindrical heating body formed by splicing the heater units 11 generates heat to provide the required heat for the system. Compared with the conventional heater which is machined as a whole, the material cost and machining cost are greatly reduced. In one embodiment, the number of heater units 11 is equal to the number of electrodes.

[0055] In some examples, without considering the difficulty of machining, a plurality of heater units are integrally formed, and the electrode pins can be connected to the heater units by, for example, a fastener, or, in other examples, as shown in FIGS. 3A and 3B, a plurality of heater units and a plurality of electrode pins are integrally formed.

[0056] The conventional direct current power supply heater for pulling single crystal silicon has low power conversion efficiency and high operating voltage. The power supply system adopts modular design and combined structure, which is composed of alternating current input, transformer, rectifier, filter circuit, voltage stabilizer, direct current output and the like. However, the design of such power supply is usually complex. Therefore, the heater in the embodiment of the present application uses alternating current power supply, which can improve the power efficiency of the power supply. The heater of the present application needs to be connected to a three-phase alternating current power supply, and the output voltage is low and adjustable. Therefore, the power supply design of the single crystal furnace is relatively simple compared with the direct current power supply, and only voltage stabilization and transformation are required without rectification and filtering. The electrical elements of the entire power supply system are reduced, and the power factor is improved. Not only the hardware cost of the equipment is reduced, but also the power loss is reduced.

[0057] Three-phase alternating current is a form of electric energy transmission, referred to as three-phase power. Three-phase alternating current power is a power source composed of three alternating current potentials with the same frequency, equal amplitude and phase difference of 120°. Actual three-phase alternating current is generated by a three-phase generator, in which three identical windings are evenly distributed with a phase difference of 120°. The three-phase windings of the generator are respectively referred to as A-phase winding, B-phase winding and C-phase winding.

[0058] In an embodiment of the present application, the plurality of electrode pins 12 are respectively used for electrically connecting three-phase alternating current of an alternating current power source. Three phases of industrial power (alternating current) are respectively connected to the three electrode pins 12 after being processed by voltage transformation and voltage stabilization of the alternating current power source. Each three electrode pins arranged along the inner surface of the cylindrical heating body in turn correspond to one phase of the three-phase alternating current.

[0059] Exemplarily, the number of electrode pins 12 is an integer multiple of 3, and the integer is greater than or equal to 2. In an embodiment, the integer ranges from 2 to 4, for example, as shown in FIG. 3A, the number of electrode pins 12 can be 6, as shown in FIG. 3B, the number of electrode pins 12 can be 9. One set of three-phase alternating current connects three electrode pins 12, two sets of three-phase alternating current connect six electrode pins 12, and three sets of three-phase alternating current connect nine electrode pins 12. Although a heater with only one set of three-phase alternating current power supply can also improve power utilization efficiency, the heater itself will generate a Lorentz force in the melt to drive the melt flow, which is not conducive to the stability of crystal growth. Therefore, in the present application, by setting the number of electrode pins 12 to be an integer multiple of 3, and the integer being greater than or equal to 2, the heater can connect at least two sets of three-phase alternating current power supply through the electrode pins 12. Compared with a single set of three-electrode alternating current heater, after the number of electrodes increases, the current between the electrodes decreases, according to the principle of electromagnetic induction, the strength of the electromagnetic field generated decreases, and the Lorentz force exerted in the silicon melt decreases. With the increase of the number of electrodes of the heater, the influence of alternating current on the convection of the melt is basically eliminated, similar results to direct current heaters are achieved, and the stability of crystal growth is enhanced. In an embodiment, the plurality of electrode pins 12 are symmetrically distributed about the central axis of the cylindrical heating body. The symmetric distribution of the plurality of electrode pins 12 causes the Lorentz forces generated by the A-phase and C-phase currents in the melt to cancel each other out, without changing the convection structure of the melt. Moreover, the electrode pins themselves are also heating components, and the symmetric distribution of the plurality of electrode pins 12 can improve the symmetry of the thermal field in the single crystal furnace and enhance the stability of crystal growth. The plurality of heater units 11 are connected to each other through the electrode pins 12, and the plurality of heater units 11 are connected to form a cylindrical heating body. The plurality of heater units 11 are identical in shape and equal in size, and the plurality of electrode pins 12 are uniformly distributed at equal intervals along the circumference of the cylindrical heating body. The electrode pins 12 connected to the heater units 11 are symmetrically distributed about the central axis of the cylindrical heating body. The included angle between 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 alternating current, and the integer multiple is greater than or equal to 2. For example, when there are 6 electrode pins 12, the included angle between two electrode pins 12 is 60°.

[0060] It is worth mentioning that the plurality of heater units 11 can also have different sizes, for example, different radii.

[0061] In one embodiment, two electrode pins 12 adjacent in the circumferential direction correspond to connecting different phases of three-phase alternating current respectively. As shown in FIG. 4, three-phase alternating current refers to a power supply capable of providing three voltages or currents with the same frequency but different phases, each of which is referred to as a phase, namely the A phase, the B phase and the C phase of the alternating current. Two electrode pins 12 adjacent in the circumferential direction correspond to connecting different phases of three-phase alternating current respectively. For example, one electrode pin 12 connects the A phase of three-phase alternating current, and the adjacent electrode pin 12 connects the B phase or the C phase of three-phase alternating current. Three electrode pins 12 adjacent in the circumferential direction correspond to connecting the A phase, the B phase and the C phase of three-phase alternating current respectively.

[0062] In one embodiment, as shown in FIG. 5, the heater includes 6 electrode pins 12 and 6 heater units 11, and the included angle of each heater unit 11 is 60°, and the included angle between two adjacent electrode pins 12 is 60°. The heater is connected to two groups of three-phase alternating current power supplies through 6 electrode pins 12, and the electrode pins 12 are symmetrically connected to the A phase, the B phase and the C phase of the three-phase alternating current power supply. The working voltage is selected in the range of 12V-60V, for example, 24V. The experiment is carried out in a 32-inch hot field, and a single crystal rod with a diameter of 300mm is grown. Compared with the heater using direct current, the working voltage of the heater using direct current is about 60V. After the silicon material is loaded into the furnace and after similar heating, melting, crystal pulling, shoulder growth, diameter growth, tailing, cooling and other steps, the crystal rod is removed for subsequent processing and analysis and testing. It is found that the crystal growth process is stable, no abnormal events related to the crystal rod growth process using the direct current heater are found, and the unit power consumption of the crystal rod is reduced by about 5%.

[0063] In the embodiment of the present application, the electrode pins 12 are located at the bottom of the inner surface of the cylindrical heating body. When the heater is arranged in the single crystal furnace, the bottom is the end away from the opening of the crucible in the single crystal furnace, that is, the end away from the raw material melt in the single crystal furnace. In one embodiment, the bottoms of adjacent heater units 11 of the heater are connected through the electrode pins 12 at the bottom of the inner surface, and the tops of adjacent heater units 11 can also be connected through the connecting pieces. The heater is placed in a Czochralski single crystal furnace, and the crucible is placed in the cylindrical heating body composed of a plurality of heater units 11 connected to each other. The material in the crucible is heated by the heater, and the bottom of the cylindrical heating body is the end away from the opening of the crucible in the single crystal furnace.

[0064] In the embodiments of the present application, a gap 13 is arranged between two adjacent heater units 11, and in the axial direction, each gap 13 is spaced apart from the corresponding electrode pin 12 by a predetermined distance. In order to ensure the heating effect of the heater, the width of the above-mentioned gap 13 is generally not too large, but also not too small, so as to prevent the accumulation of dust between the heater units and the short circuit of the heater units, and is usually 6-12 mm, which is adjusted according to the design of the resistance value of the heater. The electrode pin 12 is arranged at the bottom of the heater unit 11, and the gap 13 between the two adjacent heater units 11 does not reach the bottom of the heater unit 11 in the radial direction, so that each gap 13 is spaced apart from the corresponding electrode pin 12 by a predetermined distance. Alternatively, the length of the gap 13 in the axial direction is less than the height of the heater unit 11 in the axial direction.

[0065] As shown in FIG. 2B, which is used to show the heater unit 11 in the dashed box of FIG. 1 and FIG. 5, in the embodiments of the present application, at least one gap 15 is further arranged in each heater unit 11, and the gap 15 extends along the axial direction of the cylindrical heating body. The gap 15 arranged in each heater unit 11 extends along the axial direction of the cylindrical heating body, wherein the cylindrical heating body has a first end portion 16 and a second end portion 17 opposite to the first end portion 16, the gap 15 extends from the first end portion 16 to the second end portion 17, and there is a gap between the gap 15 and the second end portion 17, or the gap 15 extends from the second end portion 17 to the first end portion 16, and there is a gap between the gap 15 and the first end portion 16. Specifically, the gap 15 can extend from the bottom of the heater unit 11 to the top, and there is a gap between the gap 15 and the top of the heater unit 11; or the gap 15 can extend from the top (i.e. the first end portion 16) of the heater unit 11 to the bottom (i.e. the second end portion 17), and there is a gap between the gap 15 and the bottom of the heater unit 11. By the plurality of gaps 15, the heater unit 11 is formed into a S-shaped resistance, wherein the length of the gap 15 in the axial direction is less than the height of the heater unit 11 in the axial direction. Alternatively, in the radial direction, the gap 15 can also penetrate the inner and outer circumferential surfaces of the heating unit, or can not penetrate the inner and outer circumferential surfaces of the heating unit, which can be reasonably selected according to actual needs.

[0066] In the embodiments of the present application, as shown in FIG. 2B, the heater unit 11 has a plurality of gaps 15, which can include at least one first gap and at least one second gap, the first gap and the second gap are arranged alternately in the circumferential direction, the first gap extends from the first end portion 16 to the second end portion 17, the second gap extends from the second end portion 17 to the first end portion 16, or the second gap extends from the first end portion 16 to the second end portion 17, and the first gap extends from the second end portion 17 to the first end portion 16, which is not specifically limited. Wherein, the length of the gap 15 in the axial direction is less than the height of the heater unit 11 in the axial direction.

[0067] In the embodiment of the present application, 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 in the axial direction of the cylindrical heating body. Since multiple heater units 11 are connected to form the cylindrical heating body, the height of the heater unit 11 determines the height of the heater heating body, and the height of the heater heating body determines the height of the heater, which can be comparable to the height of the crucible of the single crystal furnace or can be enlarged or reduced according to the process design.

[0068] Therefore, the heater for a single crystal furnace according to the present application connects three-phase alternating current of an alternating current power supply through multiple electrode pins and splices multiple heater units to form a heater heating body, which reduces the resistance between adjacent two electrodes, so that the input working voltage of the heater is lower, the safety distance of the heater and surrounding components is improved, and the risk of "arc drawing" existing in the traditional heater is reduced. Since the heating body of the present application can be spliced by multiple heater units, compared with the traditional direct current heater which is integrally processed, the processing difficulty is small, the material cost and processing cost of the heater are reduced, and the heater of the present application uses three-phase alternating current, which improves the power efficiency of the power supply, reduces the working current, and enhances the stability of the molten silicon, compared with the direct current power supply.

[0069] The single crystal furnace, the heater and the crucible according to another aspect of the present application are described below in combination with FIG. 6 and FIG. 7. FIG. 6 shows a partial schematic structural block diagram of a single crystal furnace according to an embodiment of the present application. FIG. 7 shows a schematic diagram of a heater and a crucible according to an embodiment of the present application.

[0070] 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:

[0071] The furnace body 21 has a receiving cavity in the furnace body 21;

[0072] The crucible 22 is arranged in the receiving cavity and is used to hold a raw material melt 24 for making a single crystal rod, wherein the crucible 22 can include a quartz crucible 221 and a graphite crucible 222, and the quartz crucible 221 is arranged in the graphite crucible 222;

[0073] The heater 23 described above is arranged around the crucible 22, and the cavity in the cylindrical heating body serves as a core thermal field space and a growth channel of the single crystal rod.

[0074] In one embodiment, the heater 23 has one end of the electrode pin 12 away from the crucible 22.

[0075] A single crystal silicon growth local model is established, which includes a heater 23, a quartz crucible 221, a graphite crucible 222, a raw material melt 24, and the like. By using the finite element method and Maxwell equations, the Lorentz force generated in the raw material melt 24 (for example, a silicon melt) by the heater 23 with different electrodes is simulated and calculated under the condition of the same power frequency (for example, 50 Hz) and the same output power.

[0076] The numerical simulation results of the Lorentz force generated in the silicon melt by the heater with six electrode pins (as shown in FIG. 3A) and the heater with nine electrode pins (as shown in FIG. 3B) in the embodiments of the present application under the same heating power condition (for example, alternating current frequency of 50 Hz) are shown in FIGS. 8A, 8B and 8C. The maximum value corresponds to the position of the electrode. As shown in FIG. 8A, for the heater with three electrode pins in the related art, the maximum Lorentz force generated on the melt is more than 12 (N / m 3 ). However, as shown in FIGS. 8B and 8C, for the heater with six electrode pins and the heater with nine electrode pins according to the present application, the maximum Lorentz force generated in the silicon melt by the heater with six electrode pins is reduced to about 1.6 (N / m 3 ), and the maximum Lorentz force generated in the silicon melt by the heater with nine electrode pins is reduced to about 1 (N / m 3 ), which is reduced to 13% and 8% of the heater with three electrode pins, which means that the force acting on the initial movement of the silicon melt is greatly reduced.

[0077] Those skilled in the art can understand the structure and specific operation of each module in the single crystal furnace according to the embodiments of the present application in combination with the foregoing content, and thus the description is not repeated here for the sake of brevity.

[0078] Based on the above description, the heater for a single crystal furnace and the single crystal furnace according to the present application use three-phase alternating current connected by multiple electrode pins to connect an alternating current power supply, and connect multiple heater units into a heater heating body, which reduces the resistance between adjacent two electrodes, so that the input working voltage of the heater is lower, the safety distance of the heater and the surrounding components is improved, the risk of "arc" discharge existing in the traditional heater is reduced, and the heater according to the present application uses three-phase alternating current, which improves the power efficiency of the power supply, reduces the working current, and enhances the stability of the silicon melt, compared with the direct current power supply.

[0079] Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are only exemplary and are not intended to limit the scope of the present application. Those of ordinary skill in the art can make various changes and modifications without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0080] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0081] As will be understood by those familiar with the art, the disclosure herein describes a number of specific details any of which can be varied. It is to be understood that the disclosure in this specification includes all combinations of features described herein and any method or device disclosed or suggested herein. It is to be understood that each feature disclosed in this specification (including any accompanying claims, abstract and drawings) can be replaced by alternative features serving the same, equivalent or a similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed

[0082] It is to be understood that the features mentioned in the description are intended to be combined in all combinations, while features of the application are not limited to only those combinations. In particular, the above description has been presented for the purposes of clarity and brevity and is not intended to limit the application as claimed. It will be appreciated that features of the application are susceptible to alterations and / or modifications without departing from the scope of the application. Further, it is the intention that every aspect of the application disclosed in this specification (including any accompanying claims, abstract and drawings) can be claimed in any combination and that the disclosure is intended to cover these and any other combinations.

[0083] The above description is only specific example of the application. The scope of the application is not limited to the above description, and any person skilled in the art can easily make changes or substitutions within the scope of the application disclosed in this specification. The scope of the application should be determined by the scope of the claims.

Claims

1. A heater for a single crystal furnace, characterized by comprising: The heater comprises: a plurality of heater units, the plurality of heater units being connected to form a cylindrical heating body; a plurality of electrode pins, two adjacent heater units being connected to one electrode pin, two electrode pins being electrically connected to two ends of each heater unit, and the number of electrode pins being an integer multiple of 3, the integer being greater than or equal to 2; the plurality of electrode pins being used to electrically connect three-phase alternating current of an alternating current power supply.

2. The heater of claim 1, wherein The integer is in the range of 2-4.

3. The heater as claimed in claim 1 or 2, wherein The plurality of electrode pins are symmetrically distributed about the central axis of the cylindrical heating body.

4. The heater of any one of claims 1 to 3, wherein, Two circumferentially adjacent electrode pins correspond to different phases of the three-phase alternating current.

5. The heater of any one of claims 1 to 4, wherein, The plurality of electrode pins are uniformly distributed along the circumference of the cylindrical heating body.

6. The heater of claim 5, wherein, The electrode pins are located at the bottom of the inner surface of the cylindrical heating body, and when the heater is arranged in the single crystal furnace, the bottom is away from the opening of the crucible in the single crystal furnace.

7. The heater of any one of claims 1 to 6, wherein, A gap is provided between two adjacent heater units, and in the axial direction, each gap is spaced apart from the corresponding electrode pin by a predetermined distance.

8. The heater of claim 7, wherein, The length of the gap in the axial direction is less than the height of the heater unit in the axial direction.

9. The heater of any one of claims 1 to 8, wherein, At least one opening is further provided in each heater unit, and the opening extends along the axial direction of the cylindrical heating body.

10. The heater of claim 8, wherein The cylindrical heating body has a first end and a second end opposite to the first end, the opening extends from the first end to the second end, and there is a gap between the opening and the second end, or the opening extends from the second end to the first end, and there is a gap between the opening and the first end.

11. The heater of claim 9 or 10, wherein The heater unit has a plurality of openings, the plurality of openings include at least one first opening and at least one second opening, the first opening and the second opening are alternately arranged along the circumferential direction, the first opening extends from the first end to the second end, and the second opening extends from the second end to the first end.

12. The heater of any one of claims 9 to 11, wherein, The length of the opening in the axial direction is less than the height of the heater unit in the axial direction.

13. The heater of any one of claims 1 to 12, wherein, The plurality of heater units are integrally formed; or The plurality of heater units and the plurality of electrode pins are integrally formed.

14. The heater of any one of claims 1-13, wherein: The plurality of heater units are connected to form a cylindrical heating body, and two adjacent heater units are physically connected by one electrode pin.

15. The heater of claim 14, wherein, The electrode pin connects two adjacent heater units by a fastener.

16. The heater of any one of claims 1 to 15, wherein, The electrode pin extends in a direction parallel to the axial direction of the cylindrical heating body and away from the cylindrical heating body.

17. The heater of any one of claims 1 to 16, wherein, The material of the heater unit includes graphite.

18. The heater of any one of claims 1 to 17, wherein, The height of the heater unit is in the range of 50-500 mm.

19. A single crystal furnace, characterized by comprising: The single crystal furnace comprises: a furnace body having a receiving cavity therein; a crucible arranged in the receiving cavity and used to hold a raw material melt for making a single crystal rod; The heater of any one of claims 1-18 is arranged around the crucible, and the cavity in the cylindrical heating body serves as a core thermal field space and a growth channel of the single crystal rod.

20. The single crystal furnace of claim 19, wherein, The heater has one end of the electrode pin away from the opening of the crucible.

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