Ingot furnace

Abstract

The invention discloses an ingot furnace, and relates to the field of crystal growth, the ingot furnace comprises a cylindrical furnace body, and an accommodating space is arranged in the furnace body; the octagonal crucible is arranged in the furnace body; the octagonal protective plate is arranged on the outer side of the crucible; the bottom plate is arranged at the bottom of the crucible and matched with the protective plate to form a crucible accommodating space; the heater is a cylindrical heater, part of the heater is arranged above the crucible, and part of the heater is externally arranged on the outer side of the crucible protection plate; and the cylindrical heat insulation cage is arranged on the outer side of the heater. Through the design that the octagonal crucible is combined with the cylindrical heater and the circular / quasi-circular heat preservation cylinder, the maximum loading weight can reach 2000 KG, the productivity of silicon ingots is effectively improved, and the cost of the silicon ingots is reduced.

Description

Technical Field

[0001] The present application relates to the field of crystal growth technology, and in particular to an ingot casting furnace. Background Art

[0002] At present, the main production principle of cast single crystal is to use a polycrystalline ingot furnace to heat, melt, crystallize, anneal and cool the silicon material in five steps. Its core technology ensures that the seed crystal is not completely melted in the later stage of the silicon material, thereby providing a basic surface for the crystallization of the silicon liquid, so that the silicon liquid crystal grows along the atomic arrangement direction of the seed crystal to form a cast single crystal silicon ingot.

[0003] In order to further reduce the cost of casting single crystal silicon and increase the production capacity of a single furnace, the current thermal field of the ingot furnace is constantly expanding. The common thermal field is expanded from G5 to G7 or even G9, and the charge weight is increased from the earliest 500KG to 1300KG or even higher. However, most of the existing ingot furnaces use five-sided heating, including an upper heater and four side heaters, and no lower heater. In the production process of ingot single crystals, the melting time of silicon material is long, and the lateral temperature gradient of the entire thermal field is large. With the increase of charge amount, the larger the built-in heater is, the more difficult it is to ensure the uniformity of the entire temperature field, which is extremely unfavorable to the growth of cast single crystals, resulting in a low yield of single crystals and more difficult to stabilize the quality. Summary of the Invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a new ingot casting furnace that can make the heat radiated from the silicon ingot to the circular furnace body more uniform, resulting in a smoother and more uniform silicon ingot growth interface, less heat loss, and higher quality.

[0005] The present application proposes an ingot casting furnace, comprising:

[0006] Furnace body; the furnace body is cylindrical, and a accommodating space is provided in the furnace body;

[0007] Crucible; the crucible is octagonal and is arranged in the furnace body;

[0008] guard plate; the guard plate is octagonal and is arranged on the outside of the crucible;

[0009] Bottom plate; the bottom plate is arranged at the bottom of the crucible and cooperates with the guard plate to form a accommodating space for the crucible;

[0010] Heater; the heater is a cylindrical heater, the heater is partially arranged above the crucible, and partially arranged outside the crucible guard plate;

[0011] Insulation cage; the guard plate is cylindrical, and the insulation cage is arranged on the outside of the heater.

[0012] In an optional manner, the crucible includes a first side length and a second side length, and the length of the first side length is greater than the second side length;

[0013] More preferably, the first side length is 4-6 times the second side length;

[0014] In an optional embodiment, the length of the first side is 1345-1550 mm.

[0015] In an optional manner, the thermal insulation cage includes:

[0016] Steel frame; the steel frame includes a cylindrical steel frame body and a circular steel frame bottom plate, the steel frame body includes two identical steel frame bodies, and the two steel frame bodies are stacked; the steel frame bottom plate is arranged under one of the steel frame bodies, forming a storage space with the steel frame body;

[0017] Insulation tube; the insulation tube is a circular insulation tube; the insulation tube is arranged inside the steel frame and fits tightly with the steel frame; each steel frame is provided with a separate insulation tube.

[0018] In an optional manner, the heat-insulating cylinder is formed by at least one circular or quasi-circular layer surrounded by a plurality of flat plates, and the angle θ between adjacent flat plates is 120 to 180 degrees.

[0019] Preferably, the heat-insulating cylinder comprises at least two layers.

[0020] Preferably, the circular-shaped layer consists of at least 12 flat plates.

[0021] In an optional manner, the steel frame and the heat preservation cylinder are connected in a detachable locking manner.

[0022] In an optional embodiment, the heater includes: a side heater; the side heater is cylindrical; the side heater is composed of a first heating component and at least two foot plates spaced apart on the first heating component; the first electrode is provided on at least one foot plate;

[0023] A top heater; the top heater is square; the top heater is arranged above the side heater, the central axis of the top heater coincides with the central axis of the side heater, and the top heater consists of a second heating component and second electrodes spaced apart on the second heating component.

[0024] In an optional manner, the foot plate is arranged in the same plane as the top heater along the direction of the axial center line of the side heater and away from the end surface of the first heating element.

[0025] In an optional manner, the first electrode and the second electrode are arranged on the same plane, and a second electrode is arranged between any two adjacent first electrodes; and a first electrode is arranged between any two adjacent second electrodes.

[0026] In an optional manner, the first electrode and the second electrode are arranged on the same plane, and a second electrode is arranged between any two adjacent first electrodes; and a first electrode is arranged between any two adjacent second electrodes.

[0027] In an optional embodiment, the distance between the first electrode and the second electrode along the central axis of the heater and the edge of the crucible is greater than or equal to 50 mm; the distance between the orthographic projections of the first electrode and the second electrode along the central axis of the heater and the edge of the crucible is greater than or equal to 30 mm.

[0028] Compared with the prior art, in this application:

[0029] (1) By combining the design of an octagonal crucible with a cylindrical heater and a circular / quasi-circular insulation cylinder, the maximum loading weight can reach 2000KG, effectively improving the production capacity of silicon ingots and reducing the cost of silicon ingots.

[0030] (2) The maximum size that can be cut by the octagonal crucible set in this application is G9 (77 pieces of 158.75 mm). At the same time, the silicon ingot can also be cut into silicon blocks of specifications such as 166 mm, 182 mm, and 210 mm, and its cutting utilization rate is high, reaching more than 90% (taking the 158.75 silicon block as an example).

[0031] (3) The heat preservation tube in the present application adopts a quasi-circular structure, which is simple to prepare and convenient to maintain, and can be applied to the preparation of different silicon ingots.

[0032] (4) The combined design of the circular side heater and the top heater in this application makes the temperature field more uniform.

[0033] (5) The position setting of the first electrode and the second electrode in the present application makes the growth direction of the cast single crystal more stable and the overall quality of the cast single crystal silicon ingot is higher.

[0034] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1is a top view of an ingot casting furnace according to the present application;

[0037] Figure 2 yes Figure 1 A front view of the ingot casting furnace is shown;

[0038] Figure 3 This is a three-dimensional schematic diagram of an embodiment of the heat preservation cylinder of the present application;

[0039] Figure 4 for Figure 3 A schematic top view of the insulation cylinder shown;

[0040] Figure 5 for Figure 4 Schematic diagram of the AA direction;

[0041] Figure 6 for Figure 4 Schematic diagram of the BB direction;

[0042] Figure 7 for Figure 4 A partial enlarged schematic diagram of area A in the middle;

[0043] Figure 8 for Figure 7 Schematic diagram of the first type of circular layer;

[0044] Figure 9 for Figure 7 Schematic diagram of the second type of circular layer;

[0045] Figure 10 A three-dimensional schematic diagram of an embodiment of a heater of the present application;

[0046] Figure 11 for Figure 10 a side view of the heater shown;

[0047] Figure 12 for Figure 10 Top view of the heater shown.

[0048] Figure 13 A three-dimensional schematic diagram of an embodiment of a steel frame of the present application;

[0049] Figure 14 for Figure 13 The front view of the steel frame shown;

[0050] Figure 15 for Figure 13 a top view of the steel frame shown;

[0051] Figure 16 for Figure 13 A three-dimensional schematic diagram of the steel frame shown in FIG;

[0052] Figure 17A schematic diagram of an embodiment of a crucible of the present application;

[0053] Reference numerals:

[0054] 10-furnace body; 20-insulation tube; 30-steel frame; 40-heater; 50-bottom plate; 60-guard plate; 70-crucible;

[0055] 100 - first type circular layer; 110 - first flat plate; 111 - first upper surface; 112 - first lower surface; 113 - first side surface; 114 - second side surface; 115 - fitting surface; 120 - second flat plate; 121 - second upper surface; 122 - second lower surface; 123 - third side surface; 124 - fourth side surface; 200 - second type circular layer; 210 - third flat plate; 211 - third upper surface; 212 - third lower surface; 213 - fifth side surface; 214 - sixth side surface; 220 - fourth flat plate; 221 - fourth upper surface; 222 - fourth lower surface; 223 - seventh side surface; 224 - eighth side surface; 300 - second through hole;

[0056] 400-side heater; 410-first heating component; 411-first heating element; 4111-first heating plate; 4112-second heating plate; 412-second heating element; 420-first connecting plate; 421-first connecting portion; 422-second connecting portion; 423-third through hole; 430-foot plate; 431-first foot plate; 432-second foot plate; 440-first electrode; 500-top heater; 510-second heating component; 511-bent heating element; 520-second connecting plate; 530-second electrode.

[0057] 61 - Steel frame; 611 - Upper ring; 612 - Lower ring; 6121 - Connecting strip; 6122 - First fastener; 613 - Support plate; 6131 - First support plate; 6132 - Second support plate; 6133 - First through hole; 614 - Second fastener; 62 - Steel frame bottom plate; 621 - Arc plate; 622 - Structural plate; 623 - Third fastener; 63 - Accommodation space;

[0058] 901-first side length; 902-second side length; 903-silicon block. DETAILED DESCRIPTION

[0059] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0060] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the applicability of other processes and / or the use of other materials.

[0061] Below, refer to the attached Figure 1-2 As shown, the ingot casting furnace includes:

[0062] The furnace body 10 is cylindrical, and a furnace cavity inside the furnace body is provided with a accommodating space; an octagonal crucible 70 is arranged in the furnace body 10, and an octagonal guard plate 60 adapted to the shape of the crucible 70 is provided on the outside of the crucible 70, and a bottom plate 50 is provided at the bottom of the crucible 70. The bottom plate 50 can be octagonal, circular, rectangular or other irregular shapes. The shape of the bottom plate 50 is not limited, as long as the area of ​​the bottom plate 50 can completely cover the bottom of the crucible 70. The present application does not limit the shape of the bottom plate. Preferably, the bottom plate 50 and the guard plate 70 are adapted to be octagonal; the heater 40 is a cylindrical heater, and the heater 40 is partially arranged above the crucible 70; the heater 40 is partially arranged on the outside of the crucible guard plate 60; an insulation tube 20 is provided on the outside of the heater 60, and the insulation tube 20 is cylindrical or quasi-cylindrical.

[0063] In this application, the design of an octagonal crucible combined with a cylindrical heater and a circular or quasi-circular insulation cylinder can achieve a maximum loading weight of 2000KG, effectively improving the production capacity of silicon ingots and reducing the cost of silicon ingots.

[0064] In an optional embodiment, the crucible 70 includes a first side length 901 and a second side length 902 , wherein the first side length 901 is greater than the second side length 902 , thereby maximizing the utilization rate of the silicon ingot.

[0065] Preferably, the first side length 901 of the crucible 70 is 4-6 times the second side length 902 , for example, 4 times, 4.1 times, 4.2 times, 4.3 times, 4.4 times, 4.5 times, 4.6 times, 4.7 times, 4.8 times, 4.9 times, 5 times, 5.1 times, 5.2 times, 5.3 times, 5.4 times, 5.5 times, 5.6 times, 5.7 times, 5.8 times, 5.9 times, or 6 times; thereby maximizing the utilization rate of the silicon ingot.

[0066] More preferably, the length of the first side 901 is 1345-1550 mm, for example, 1345 mm, 1350 mm, 1355 mm, 1360 mm, 1365 mm, 1370 mm, 1375 mm, 1380 mm, 1385 mm, 1390 mm, 1395 mm, 1400 mm, 1405 mm, 1410 mm, 1415 mm, 1420 mm, 1425 mm, 1430 mm, 1445 mm, 1456 mm, 1460 mm, 1470 mm, 1480 mm, 1490 mm, 1501 mm, 1515 mm, 1520 mm, 1530 mm, 1540 mm, 1551 mm, 1565 mm, 1570 mm, 1580 mm, 1585 mm, 1590 mm, 1601 mm, 1610 mm, 1620 mm, 1625 mm, 1630 mm, 1640 mm, 1651 mm, 1660 mm, 1670 mm, 1680 mm, 1690 mm, 1701 mm, 1710 mm, 1715 mm, 1720 mm, 1725 mm, 1730 mm, 1731 mm, 1740 mm, 1741 mm, 1742 mm, mm, 1440mm, 1445mm, 1450mm, 1455mm, 1460mm, 1465mm, 1470mm, 1475mm, 1480mm, 1485mm, 1490mm, 14 95mm, 1500mm, 1505mm, 1510mm, 1515mm, 1520mm, 1525mm, 1530mm, 1535mm, 1540mm, 1545mm, 1550mm.

[0067] The size of the crucible will affect the amount of loss in the subsequent cutting of cast silicon blocks. When the size of the crucible is controlled so that the first side length is 1345-1550mm, the first side length is 4-6 times the second side length. This not only allows more silicon material to be loaded, but also minimizes the amount of loss in cutting, thereby effectively increasing the production capacity of silicon ingots and reducing the cost of silicon ingots.

[0068] In a specific embodiment, Figure 17 As shown, when the second side length 902 is 1510 mm and the first side length is 282.2 mm, 77 silicon blocks of 158.7 mm can be cut; the utilization rate of the silicon material (weight of the silicon ingot / amount of material) can reach more than 90%.

[0069] In the ingot casting furnace, the ingot casting furnace includes a crucible loaded with silicon material, a guard plate and a bottom plate are arranged outside the crucible, a heater is arranged above the crucible, and an insulation cage is arranged outside the guard plate and the bottom plate. The insulation cage includes a steel frame and an upper insulation layer, an insulation tube and a lower insulation layer, wherein the upper insulation layer is arranged on the inner side of the top of the steel frame; the insulation tube is arranged on the inner side of the middle of the steel frame, and the lower insulation layer is arranged on the inner side of the bottom of the steel frame; the steel frame is a split structure, divided into upper and lower steel frames, the inner side of the upper steel frame has an upper insulation layer and an upper insulation tube, and the inner side of the lower steel frame has a lower insulation tube and a lower insulation layer, and the upper and lower steel frames form a sealed insulation space that can be opened and closed. In the early stage of crystalline silicon melt and crystal growth in the ingot casting furnace, the insulation cage is a sealed insulation space. As the crystal growth progresses, the insulation cage gradually opens, allowing the heat inside the insulation cage to exchange with the heat outside the insulation cage. According to the different processes, different temperature gradients are formed, and finally the growth of crystalline silicon ingot is completed. It can be seen that the accommodation space formed by the insulation cage will affect the size of the crucible, and the insulation environment of the insulation cage also has a relatively important influence on the growth of ingot crystalline silicon; in addition, the insulation cage needs to support the insulation layer and insulation tube, so its strength and load-bearing capacity are also relatively important.

[0070] In an optional embodiment, the insulation cage is formed by combining a steel frame 30 and an insulation tube 20, wherein the steel frame 30 is a cylindrical steel frame 30; the steel frame 30 has an upper top; a middle side and a lower bottom; the insulation tube 20 is a cylindrical insulation tube 20; the insulation tube 20 is arranged on the inner side of the middle side of the steel frame 30, and fits tightly with the steel frame 30 to form a cylindrical insulation cage.

[0071] Among them, refer to the attached Figure 3-4 and 13-16, the steel frame 30 includes a cylindrical steel frame 30 body; the steel frame 30 body includes two identical steel frame bodies 61, and the two steel frame bodies 61 are symmetrically stacked to form the steel frame 30 body; the steel frame 30 includes a steel frame bottom plate 62, and the steel frame bottom plate 62 is arranged under one of the steel frame bodies 61, forming a steel frame 30 with a accommodating space 63 together with the steel frame 30 body.

[0072] The heat preservation tube 20 is a circular heat preservation tube 20, which is arranged inside the steel frame 61. Each separate steel frame 61 is provided with a separate circular heat preservation tube 20. Therefore, when the two steel frames 61 need to be separated, the heat preservation tube 20 can also be separated as the steel frames 61 are separated.

[0073] The combination of the circular insulation tube 20 and the circular steel frame 30 creates a heat-insulating cage with a circular housing 63. For the same ingot casting furnace, the circular housing 63 is significantly larger than the square housing 63, significantly increasing the space within the furnace. Furthermore, the circular heat dissipation method ensures more uniform heat distribution within the furnace, resulting in a smoother and more uniform silicon ingot growth interface, less heat loss, and higher quality.

[0074] In one embodiment, the steel frame 61 and the insulation cylinder 20 are connected by a removable locking mechanism, such as a bolt connection, a latch connection, or a slot connection. This not only increases the strength of the insulation cylinder 20 and the steel frame 61, but also facilitates disassembly and maintenance, effectively reducing maintenance costs for the insulation cage.

[0075] In an optional embodiment, the steel frame 61 includes an upper ring 611 and a lower ring 612, and a plurality of support plates 613 are disposed between the upper ring 611 and the lower ring 612 via second fasteners 614. This makes the steel frame 61 more secure.

[0076] Preferably, the upper ring 611 and the lower ring 612 are formed by connecting and assembling a plurality of connecting strips 6121 through a first fastener 6122; thus, the assembly is simple, and the disassembly and assembly are convenient, and maintenance is convenient.

[0077] In an optional embodiment, the insulation tube 20 is formed by splicing and enclosing at least twelve flat plates 22. The support plate 613 on the steel frame 61 includes a first support plate 6131. ​​Multiple first support plates 6131 are arranged at intervals between the upper ring 611 and the lower ring 612. The adjacent two first support plates 6131 are installed in cooperation with the flat plate 22.

[0078] In an optional embodiment, a flat plate 22 is provided between two adjacent first support plates 6131 , that is, the distance between two adjacent first support plates 6131 in the radial direction of the steel frame 30 body is equal to the size of one flat plate 22 of the insulation cylinder 20 ;

[0079] In an optional embodiment, the distance between two connected first support plates 6131 is the straight-line distance between the flat plate 22 of the heat preservation cylinder 20 and the steel frame 61 .

[0080] In a specific embodiment, Figure 6As shown, the insulation tube 20 includes two layers, and the outer insulation tube 20 is formed by 9 first flat plates 110 and 9 second flat plates 120. The upper side length of the cross section of the first flat plate 110 is a, and the distance on the upper side of the cross section of the first flat plate 110 is the straight-line distance of the flat plate 22 that fits the steel frame 61. The distance between the two first support plates 6131 is set to a, thereby making the insulation tube 20 more closely combined with the steel frame 61; the upper side length of the cross section of the second flat plate 120 is the same as the distance between the two first support plates 6131. The sides of the adjacent first flat plates 110 are on the same straight line segment, forming a distance b, where b is the straight-line distance of the flat plate 22 in contact with the steel frame 61. The distance between the two first support plates 6131 is set to b, and a second support plate 6132 can be set between the two first support plates 6131, with the second support plate 6132 being located in the middle of the two first support plates 6131. ​​This allows the thermal insulation cylinder 20 to be more tightly combined with the steel frame 61, thereby improving the overall strength and thermal insulation performance of the thermal insulation cage.

[0081] In one optional embodiment, the insulation tube 20 comprises two layers, each formed by joining at least twelve flat plates 22. The two insulation layers are connected by bonding, clamping, welding, bolts, latches, or the like, with an outer flat plate 22 disposed between the two connected first support plates 6131. ​​This allows for a tighter connection between the insulation tube 20 and the steel frame 61.

[0082] Preferably, the support plate 613 further includes a second support plate 6132 , and at least one second support plate 6132 is arranged between two first support plates 6131 , and the second support plate 6132 is arranged between the two first support plates 6131 , thereby further improving the overall strength and thermal insulation performance of the insulation cage.

[0083] More preferably, the second support plate 6132 is provided with a first through hole 1133, and the first through hole 1133 corresponds to the second through hole 300 on the flat plate 22 of the insulation tube 20 to which the second support plate 6132 is attached; thereby, a detachable connection method can be used, such as a pin connection, a screw connection, a bolt connection, etc. to connect the second support plate 6132 to the flat plate 22 on the insulation tube 20.

[0084] In an optional embodiment, the steel frame base plate 62 includes four arc plates 621 and at least two structural plates 122; the arc circumference of the four arc plates 621 is between 1 / 5 and 1 / 4 of the circumference of the steel frame base plate 62, and the four arc plates 621 are evenly arranged on the steel frame base plate 62 along the circumference of the steel frame base plate 62; a third fastener 623 is arranged between two adjacent arc plates 621; the two structural plates 122 are perpendicular to each other to form a cross structure, and the end faces of the two connecting plates are respectively arranged on the four arc plates 621.

[0085] Preferably, the steel plate bottom plate includes four structural plates 122 forming a tic-tac-toe structure and arranged on the four arc plates 621 .

[0086] In an alternative approach, such as Figure 3-9 As shown in the figure, the heat preservation tube 20 includes at least one circular or quasi-circular layer formed by the flat plates; wherein the flat plates are plate-shaped objects with two parallel and flat surfaces; the quasi-circular layer means that the heat preservation tube 20 is formed relatively close to a circle, for example, it can be a polygonal layer with more than twelve sides; the heat preservation tube 20 is formed by a plurality of flat plates, and the angle θ between adjacent flat plates is 120 to 180 degrees, for example, it can be 120 degrees, 125 degrees , 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 156 degrees, 157 degrees, 158 degrees, 159 degrees, 160 degrees, 161 degrees, 162 degrees, 163 degrees, 164 degrees, 165 degrees, 166 degrees, 167 degrees, 168 degrees, 169 degrees, 170 degrees, 171 degrees, 172 degrees, 17 degrees, 174 degrees, 175 degrees, 176 degrees, 177 degrees, 178 degrees or 179 degrees.

[0087] Among them, the flat plates are enclosed by welding, bonding, clamping, convex-groove, bolt assembly and other connection methods, which are not limited in this application.

[0088] In the present application, the heat-insulating tube 20 is formed into a circular layer by splicing a plurality of flat plates, which is easy to disassemble and maintain, thereby reducing the maintenance cost of the heat-insulating tube 20 .

[0089] In one optional embodiment, the circular or quasi-circular layer is composed of at least 12 flat plates; for example, there can be 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, etc.

[0090] In an optional manner, the flat plate includes an upper surface, a lower surface, a side surface and a cross section, and the cross section is a trapezoidal structure; the flat plate forms a quasi-circular layer by at least partial adhesion between the side surfaces or partial adhesion between the lower surface and the side surfaces.

[0091] In a specific embodiment, Figure 5-6As shown, the first plate 110 includes a first upper surface 111, a first lower surface 112, a first side surface 113, a second side surface 114, and a cross-section; the cross-section of the first plate 110 is a trapezoidal structure; the second plate 120 includes a second upper surface 121, a second lower surface 122, a third side surface 123, a fourth side surface 124, and a cross-section; the cross-section of the second plate 120 is a trapezoidal structure; the first side surface 113 of the first plate 110 and the fourth side surface 124 of the second plate 120 are completely or partially affixed to each other, connected end to end, and alternately spliced ​​to form a quasi-circular layer. Thus, through simple assembly, the thermal insulation cylinder 20 can be formed.

[0092] Furthermore, in a more specific embodiment, the cross-section of the first flat plate 110 is a symmetrical inverted trapezoidal structure; the acute angle of the first flat plate 110 is greater than the acute angle of the second flat plate 120. This allows the shape of the thermal insulation tube 20 to be closer to a circle. The difference between the angles of the first and second flat plates 110, 120 can further control the angles between the flat plates in the quasi-circular layer. In this specific embodiment, by controlling the acute angle of the first flat plate 110 to be greater than the acute angle of the second flat plate 120, the thermal insulation tube 20 is made closer to a circular shape.

[0093] It is worth noting that the cross-section of the flat plate in the present application is a trapezoidal or inverted trapezoidal structure, and the acute angle of the flat plate refers to the acute angle formed by the upper surface or lower surface of the flat plate and the side surface; for example, the first flat plate 110 is an inverted trapezoidal structure, and its acute angle is the acute angle formed by the first upper surface 111 and the first side surface 113 or the second side surface 114; the second flat plate 120 is a trapezoidal structure, and its acute angle is the acute angle formed by the second lower surface 122 and the third side surface 123 or the fourth side surface 124.

[0094] In a specific embodiment, Figure 5 and 7 As shown, the third plate 210 includes a third upper surface 211, a third lower surface 212, a fifth side surface 213, a sixth side surface 214, and a cross section; the cross section of the third plate 210 is a trapezoidal structure; the fourth plate 220 includes a fourth upper surface 221, a fourth lower surface 22, a seventh side surface 223, an eighth side surface 224, and a cross section; the cross section of the fourth plate 220 is a trapezoidal structure; one end of the third lower surface 212 of the third plate 210 partially abuts the seventh side surface 223 of the fourth plate 220; the other end of the fourth lower surface 22 of the third plate 210 partially abuts the eighth side surface 224 of the fourth plate 220, so that the third plate 210 and the fourth plate 220 are connected end to end to form a quasi-circular layer. Thus, the thermal insulation cylinder 20 can be formed by simple assembly.

[0095] Furthermore, in a more specific embodiment, the cross-section of the third plate 210 is a symmetrical trapezoidal structure; the cross-section of the fourth plate 220 is a symmetrical trapezoidal structure; the acute angle of the third plate 210 is equal to the acute angle of the fourth plate 220; thus, by controlling the angle between the third plate 210 and the fourth plate 220, the shape of the insulation tube 20 is more uniform and closer to a circular insulation tube 20.

[0096] It is worth noting that the cross-section of the flat plate in the present application is a trapezoidal or inverted trapezoidal structure, and the acute angle of the flat plate refers to the acute angle formed between the upper surface or lower surface of the flat plate and the side surface; for example, the third flat plate 210 is an inverted trapezoidal structure, and its acute angle is the acute angle formed by the third upper surface 211 and the fifth side surface 213 or the sixth side surface 214; the fourth flat plate 220 is a trapezoidal structure, and its acute angle is the acute angle formed by the fourth upper surface 221 and the seventh side surface 223 or the eighth side surface 224.

[0097] It is worth noting that in this application, "equal angles" does not mean exactly the same. Errors between + / - 2 degrees caused by processing errors, etc. fall within the range of equal angles in this application.

[0098] In one embodiment, the insulation tube 20 includes two layers: an inner layer and an outer layer. The inner layer is a first-type circular layer 100, and the outer layer is a second-type circular layer 200. The multi-layer structure of the insulation tube 20 not only improves the insulation performance of the insulation tube 20, but also makes the spliced ​​insulation tube 20 stronger.

[0099] In a specific embodiment, Figure 1-5 As shown, the first circular layer 100 of the heat preservation tube 20 is formed by the first flat plate 110 and the second flat plate 120 , and the second circular layer 200 is formed by the third flat plate 210 and the fourth flat plate 220 .

[0100] Specifically, in the first type circular layer 100, the first flat plate 110 includes a first upper surface 111, a first lower surface 112, a first side surface, a second side surface 114 and a cross section; the cross section of the first flat plate 110 is an inverted trapezoidal structure; the second flat plate 120 includes a second upper surface 121, a second lower surface 122, a third side surface 123, a fourth side surface 124 and a cross section; the cross section of the second flat plate 120 is an inverted trapezoidal structure; the first side surface of the first flat plate 110 and the fourth side surface 124 of the second flat plate 120 are completely or partially fitted together, connected end to end and alternately spliced ​​to form the first type circular layer 100. In the second type circular layer 200, the third plate 210 includes a third upper surface 211, a third lower surface 212, a fifth side surface 213, a sixth side surface 214 and a cross section; the cross section is a trapezoidal structure; the fourth plate 220; the fourth plate 220 includes a fourth upper surface 221, a fourth lower surface 22, a seventh side surface 223, an eighth side surface 224 and a cross section; the cross section is a trapezoidal structure; one end of the third lower surface 212 of the third plate 210 is partially aligned with the seventh side surface 223 of the fourth plate 220; the other end of the fourth lower surface 22 of the third plate 210 is partially aligned with the eighth side surface 224 of the fourth plate 220; so that the third plate 210 and the fourth plate 220 are connected end to end to form the second type circular layer 200.

[0101] Furthermore, in a specific embodiment, during the assembly of the inner and outer layers, the third flat plate 210 is bonded to the first flat plate 110, and the second flat plate 120 is bonded to the fourth flat plate 220. This allows for a tighter connection between the inner and outer layers, improved airtightness of the insulation tube 20, and better insulation performance.

[0102] Preferably, the upper surface of the first flat plate 110 has a contact surface 115 that contacts the lower surface of the fourth flat plate 220 , thereby further improving the heat preservation performance of the heat preservation cylinder 20 .

[0103] Preferably, the width of the third flat plate 210 in the radial direction of the axis of the insulation tube 20 is greater than the width of the lower surface of the first flat plate 110; and the width of the second flat plate 120 in the radial direction of the axis of the insulation tube 20 is equal to the width of the lower surface of the fourth flat plate 220. This further improves the insulation performance of the insulation tube 20. It is worth noting that in this application, the term "equal width" does not necessarily mean exactly the same. Errors of + / - 1 cm due to manufacturing errors, etc., fall within the scope of equal width in this application.

[0104] Preferably, the difference in acute angles between the first plate 110 and the second plate 120 is equal to the acute angle between the third plate 210 and the fourth plate 220. This allows the inner and outer layers to fit more closely together, resulting in better insulation performance and increased strength of the insulation tube 20.

[0105] In a specific embodiment, a second through hole 300 is provided on the first circular layer 100 and the second circular layer 200. The second through hole 300 can be used to set fasteners such as pins and bolts, thereby further increasing the strength of the insulation tube 20 and making the insulation tube 20 more tightly combined.

[0106] In an optional embodiment, the plate is made of graphite or carbon-carbon.

[0107] The insulation cylinder 20 provided in this application is easy to disassemble and maintain, which greatly reduces the maintenance cost of the insulation cylinder 20. In addition, the application of this type of circular insulation cylinder 20 in the ingot casting furnace can increase the accommodation space of the ingot casting furnace, effectively increase the production capacity of the ingot casting furnace, and reduce the cost of ingot casting.

[0108] In an alternative embodiment, see the attached Figure 10-12 , the heater includes a side heater 400 and a top heater 500;

[0109] The side heater 400 is cylindrical and consists of a first heating component 410 and at least two foot plates 430. The at least two foot plates 430 are spaced apart on the first heating component 410. Preferably, the at least two foot plates 430 are evenly spaced apart on the first heating component 410, and at least one foot plate 430 is provided with a first electrode 440.

[0110] The top heater 500 is square; the top heater 500 is arranged above the side heater 400, and the central axis of the top heater 500 coincides with the central axis of the side heater 400; the top heater 500 is composed of a second heating component 520 and a second electrode 530, and the second electrodes 530 are distributed at intervals on the second heating component 520; preferably, the second electrodes 530 are evenly distributed at intervals on the second heating component 520.

[0111] Therefore, by setting up a cylindrical side heater, the heat radiated to the silicon ingot by the heater is more uniform, making the growth direction of the cast single crystal silicon ingot or the cast polycrystalline silicon ingot more stable, thereby ensuring the overall quality of the cast single crystal silicon ingot or the cast polycrystalline silicon ingot, improving the single crystal yield, the weight of the single furnace charge, and reducing production costs.

[0112] In one optional embodiment, the first heating component 410 includes a first heating element 411 and a second heating element 412; the structure of the first heating element 411 is at least one of a U-shaped plate, an n-shaped plate, an S-shaped plate, or a serpentine plate. The first heating element 411 includes two connected side portions; it is worth noting that the U-shaped plate and the n-shaped plate have the same structure, except that the opening directions are opposite during the heater connection process; the S-shaped plate is a structure prepared by connecting a U-shaped plate and an n-type plate end to end; and the serpentine plate is a structure prepared by connecting multiple S-shaped plates end to end.

[0113] The second heating element 412 is a rectangular structure; for example, it can be a rectangle or a square; the second heating element 412 includes two connected side portions;

[0114] The second heating elements 412 are spaced apart between the first heating elements 411 ; preferably, the second heating elements 412 are evenly spaced apart between the first heating elements 411 ;

[0115] One side portion of any first heating element 411 is connected end to end with one side portion of another first heating element 411 or one side portion of the second heating element 412 via the first connecting plate 420 to enclose and form the first heating assembly 410 ;

[0116] The foot plate 430 includes a first foot plate 431 and a second foot plate 432. The first foot plate 431 is provided with a first electrode 440 and is connected to the second heating element 412. The second foot plate 432 is provided on the first heating element 411. The first foot plate 431 and the second foot plate 432 are alternately arranged on the first heating component.

[0117] Thus, the formation of the first heating element 411 and the second heating element 412 is realized by connecting the first heating element 411 and the second heating element 412, and the formation of the side heater 400 is realized by connecting the first foot plate 431, the second foot plate 432 and the first electrode 440 with the first heating element 411 and the second heating element 412.

[0118] Furthermore, the first heating element 411 is composed of a first heating plate 4111 with a U-shaped structure and a second heating plate 4112 with an n-shaped structure; one side of the first heating plate 4111 is connected end-to-end with one side of the second heating plate 4112 or one side of the second heating element 412; or one side of the second heating plate 4112 is connected end-to-end with one side of the first heating plate 4111 or one side of the second heating element 412. Thus, the first heating element 411 is formed.

[0119] Furthermore, the first heating plate 4111 and the second heating plate 4112 are flat plates; the flat plates are plates with parallel upper and lower surfaces and are straight planes, and their production is simpler and cheaper than that of curved plates or V-shaped plates, thereby further reducing the manufacturing cost of the heater.

[0120] Furthermore, the second heating element 412 is a flat plate, thereby further reducing the manufacturing cost of the heater.

[0121] In an optional embodiment, the second foot plate 432 is arranged on the second heating plate 4112, the lower end surface of the second foot plate 432 is aligned with the upper end surface of the n-type groove of the second heating element 412, and the central axis of the second foot plate 432 is aligned with the central axis of the second heating plate 4112; thereby better realizing the coordinated connection between the side heater 400 and the top heater 500.

[0122] In an optional embodiment, the lower end surface of the first foot plate 431 is aligned with the lower end surface of the second heating element 412, and the central axis of the first foot plate 431 is aligned with the central axis of the second heating element 412. This better realizes the connection between the side heater 400 and the top heater 500.

[0123] In an optional embodiment, the first connecting plate 420 includes a first connecting portion 421 and a second connecting portion 422, and the first connecting portion 421 and the second connecting portion 422 are at least partially connected to the side of the first heating element 411 or the second heating element 412, respectively. During the process of connecting the first heating element 411 or the second heating element 412, the first connecting portion 421 and the second connecting portion 422 can be completely connected to the side of the first heating element 411 or the second heating element 412, or can be partially connected; thus, the assembly of the heater is achieved by splicing, making subsequent disassembly and assembly simple, maintenance convenient, and reducing the maintenance cost of the heater.

[0124] Furthermore, the first connecting portion 421 and the second connecting portion 422 are formed as an arc-shaped plate or a V-shaped plate; since the first heating element 411 or the second heating element 412 is a flat plate and needs to be enclosed into a cylindrical shape; therefore, forming the first connecting plate 420 into an arc-shaped plate or a V-shaped plate can enable the first connecting plate 420 to better fit the side of the first heating element 411 or the second heating element 412, thereby further realizing the preparation of the heater.

[0125] Furthermore, the first connecting part 421 and / or the second connecting part 422 has a third through hole 423; the first heating element 411 and / or the second heating element 412 is connected to the first connecting part 421 and / or the second connecting part 422 by bolts, screws or pins; thereby, the preparation of the heater can be further realized.

[0126] In an optional manner, the second heating component 520 includes at least two bent heating elements 521 symmetrically arranged on the same plane; the second electrodes 530 are distributed on the second heating component 520 at intervals; preferably, the second electrodes 530 are evenly distributed on the second heating component 520.

[0127] Furthermore, a second connecting plate 520 is provided on the bent heating element 521. This allows the second heating component 520 to be spliced, making the second heating component 520 easier to maintain.

[0128] In an optional embodiment, the foot plate 430 is arranged in the same plane as the top heater 500 along the axial centerline of the side heater 400, away from the end surface of the first heating element 411. In this way, the side heater 400 can better support the top heater 500 and make the temperature in the furnace more uniform.

[0129] In an optional embodiment, the first electrode 440 and the second electrode 530 are arranged on the same plane, with a second electrode 530 disposed between any two adjacent first electrodes 440, and a first electrode 440 disposed between any two adjacent second electrodes 530. This allows for a more uniform temperature within the furnace, thereby ensuring the overall quality of the cast single crystal silicon ingot, improving the yield of the single crystal, the weight of the material in a single furnace, and reducing production costs.

[0130] The heater is formed by splicing flat plates, which is easy to disassemble and maintain, greatly reducing the maintenance cost of the heater.

[0131] In an optional embodiment, the first electrode 440 and the second electrode 530 are spaced at a distance of greater than or equal to 50 mm from the edge of the crucible 70 along the central axis of the heater 40 ; for example, the distance may be 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, or 100 mm;

[0132] The distance between the orthographic projection of the first electrode 440 and the second electrode 530 along the central axis of the heater 40 and the edge of the crucible 70 is greater than or equal to 30 mm. For example, the distance can be any of 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, or 100 mm. Preferably, the distance between the orthographic projection of the first electrode 440 and the second electrode 530 along the central axis of the heater 40 and the edge of the crucible 70 is greater than or equal to 30 mm and 60 mm. This can make the temperature in the furnace more uniform, thereby ensuring the overall quality of the silicon ingots in the single crystal casting furnace.

[0133] The ingot casting furnace disclosed in the present application is described in detail below with reference to several specific embodiments. It is worth noting that the following description is merely illustrative and not intended to limit the invention.

[0134] Example 1

[0135] refer to Figure 1-2As shown, the ingot furnace includes a cylindrical furnace body 10; the inner diameter of the furnace body is 2400mm, and an octagonal crucible 70 is arranged in the furnace body 10, the first side length of the octagonal crucible is 282.2mm, and the second side length is 1510mm; the inner diameter of the crucible is (1345-1510)X(1345-1510)X540mm, and an octagonal guard plate 60 adapted to the shape of the crucible 70 is arranged on the outside of the crucible 70, and a bottom plate 50 is arranged at the bottom of the crucible 70, and the bottom plate 50 is adapted to the guard plate 70 into an octagon; the heater 40 is a cylindrical heater, and the heater 40 is partially arranged above the crucible 70; the heater 40 is partially arranged on the outside of the crucible guard plate 60; an insulation tube 20 is arranged on the outside of the heater 60, and the insulation tube 20 is cylindrical; a steel frame 30 is arranged on the outside of the insulation tube 20; the insulation tube 20 and the steel frame 30 form an insulation cage.

[0136] The steel frame includes a steel frame body formed by two steel frame bodies 61 and a steel frame bottom plate 62 ; the heat-insulating cylinder 20 is arranged inside the steel frame body 61 , and each individual steel frame body 61 is provided with an individual circular heat-insulating cylinder 20 .

[0137] The heat preservation tube 20 consists of two layers, the outer layer is formed by nine first flat plates 110 and nine second flat plates 120 ; the inner layer is formed by nine third flat plates 210 and nine fourth flat plates 220 .

[0138] The heater includes a top heater 400 and a side heater 500; the side heater 500 is cylindrical and the top heater 400 is square; the top heater 400 is arranged above the side heater 500, and the central axis of the top heater 400 coincides with the central axis of the side heater 500.

[0139] The side heaters are arranged with three first electrodes 440, and the top heater is arranged with three second electrodes 530. The first electrodes 440 and the second electrodes 530 are arranged on the same plane. A second electrode 530 is arranged between any two adjacent first electrodes 440, and a first electrode 440 is arranged between any two adjacent second electrodes 530. The distance between the first and second electrodes 440, 530 and the edge of the crucible 70 along the central axis of the heater 40 is greater than or equal to 50 mm. The orthographic projections of the first and second electrodes 440, 530 along the central axis of the heater 40 are 30 mm from the edge of the crucible 70.

[0140] The ingot casting furnace is loaded with seed crystals and silicon materials at the bottom, and the silicon materials are heated and melted. When the seed crystals are not completely melted, the seed crystals are seeded and the silicon liquid is allowed to crystallize and grow along the atomic arrangement direction of the seed crystals to grow single crystal silicon ingots. The weight of the silicon material that can be loaded in the ingot casting furnace of this embodiment is 2000KG. The resistivity and minority carrier lifetime of the grown single crystal silicon ingots are tested, and the yield rate is 55-60%.

[0141] Example 2

[0142] The difference from Example 1 is that the first electrode 440 and the second electrode 530 are greater than or equal to 50 mm away from the edge of the crucible 70 along the central axis of the heater 40; the first electrode 440 and the second electrode 530 of the side heater used in Example 2 have a positive projection distance of 60 mm from the edge of the crucible 70 along the central axis of the heater 40.

[0143] The weight of silicon material that can be loaded into the ingot casting furnace of this embodiment is 2000 kg. The resistivity and minority carrier lifetime of the grown single crystal silicon ingot are tested, and the yield is 50-55%.

[0144] Comparative Example 1

[0145] The difference from the first embodiment is that a quadrilateral crucible is used, and the side length of the crucible is 1220 mm.

[0146] The weight of silicon material that can be loaded into the ingot casting furnace of this comparative example is 1200 kg. The resistivity and minority carrier lifetime of the grown single crystal silicon ingot are tested, and the yield is 50-55%.

[0147] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0148] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0149] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0150] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0151] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. An ingot casting furnace, characterized in that: include: Furnace body; the furnace body is cylindrical, and a accommodating space is provided in the furnace body; Crucible; The crucible is octagonal and is arranged in the furnace body; guard plate; the guard plate is octagonal and is arranged on the outside of the crucible; Bottom plate; the bottom plate is arranged at the bottom of the crucible and cooperates with the guard plate to form a accommodating space for the crucible; Heater; the heater is a cylindrical heater, the heater is partially arranged above the crucible, and partially arranged outside the crucible guard plate; The heat insulation cage is cylindrical and is arranged outside the heater.

2. The ingot casting furnace according to claim 1, characterized in that The crucible includes a first side length and a second side length; the length of the first side length is greater than the second side length; preferably, the first side length is 4-6 times the length of the second side length; more preferably, the length of the first side length is 1345-1550 mm.

3. The ingot casting furnace according to claim 1, wherein The thermal insulation cage comprises: Steel frame; the steel frame includes a cylindrical steel frame body and a circular steel frame bottom plate, the steel frame body includes two identical steel frame bodies, and the two steel frame bodies are stacked; the steel frame bottom plate is arranged under one of the steel frame bodies, forming a storage space with the steel frame body; Insulation tube; the insulation tube is a circular insulation tube; the insulation tube is arranged inside the steel frame and fits tightly with the steel frame; each steel frame is provided with a separate insulation tube.

4. The ingot casting furnace according to claim 3, characterized in that The heat-insulating cylinder is formed by a plurality of flat plates to form at least one circular or quasi-circular layer, and the angle θ between adjacent flat plates is 120-180 degrees.

5. The ingot casting furnace according to claim 4, characterized in that: The heat-insulating cylinder comprises at least two layers.

6. The ingot casting furnace according to claim 4, characterized in that The circular layer is composed of at least 12 flat plates.

7. The ingot casting furnace according to claim 3, characterized in that: The steel frame and the heat-insulating cylinder are connected in a detachable locking manner.

8. The ingot casting furnace according to claim 1, wherein: The heater comprises: The heater comprises: a side heater; the side heater is cylindrical; the side heater is composed of a first heating component and at least two foot plates spaced apart on the first heating component; a first electrode is provided on at least one foot plate; A top heater; the top heater is square; the top heater is arranged above the side heater, the central axis of the top heater coincides with the central axis of the side heater, and the top heater consists of a second heating component and second electrodes spaced apart on the second heating component.

9. The ingot casting furnace according to claim 8, characterized in that: The foot plate is arranged in the same plane as the top heater along the direction of the axial center line of the side heater and away from the end surface of the first heating element.

10. The ingot casting furnace according to claim 9, characterized in that: The first electrode and the second electrode are arranged on the same plane, and a second electrode is arranged between any two adjacent first electrodes; a first electrode is arranged between any two adjacent second electrodes; preferably, the distance between the first electrode and the second electrode along the central axis of the heater and the edge of the crucible is greater than or equal to 50 mm; the orthographic projections of the first electrode and the second electrode along the central axis of the heater are greater than or equal to 30 mm from the edge of the crucible.

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