A boltless splicing monocrystalline silicon heater

Abstract

This utility model discloses a boltless splicing monocrystalline silicon heater, including a main heating coil and electrode feet. The main heating coil is composed of multiple heating elements connected end-to-end by a mortise and tenon structure to form a ring structure. Each heating element has several alternating first and second recesses arranged vertically along its circumference. A foot plate connection area is provided on one side of each heating element, containing at least one foot plate boss, with multiple bosses evenly distributed within the connection area. The electrode feet are used to connect the monocrystalline furnace electrode and conduct current to the main heating coil. The upper end of the electrode feet has a foot plate groove that mates with the foot plate boss, forming a mortise and tenon structure. This utility model solves the problem of loosening and oxidation failure of metal bolts under high-temperature environments caused by differences in thermal expansion coefficients in traditional bolted connections.

Description

Technical Field

[0001] This utility model belongs to the technical field of monocrystalline silicon production equipment, and specifically relates to a boltless splicing monocrystalline silicon heater. Background Technology

[0002] In the Czochralski (CZ) single-crystal silicon production process, the heater is one of the core systems of the CZ furnace, and its performance directly determines the single-crystal formation rate and production stability. The core function of the heater is to provide continuous and uniform heat to the quartz crucible, melting the solid silicon raw material to form liquid silicon, and precisely maintaining the temperature gradient at the interface between the molten silicon and the single crystal growth to ensure that the single crystal grows stably according to the preset crystal orientation. Therefore, the structural reliability and service life of the heater are crucial to the production efficiency of single-crystal silicon.

[0003] Currently, graphite is the mainstream material for industrial heaters. Through multiple machining processes such as turning, milling, planing, and grinding, graphite blocks are processed into heater structures that meet the design requirements of the thermal field. Based on structural differences, graphite heaters on the market are mainly divided into two categories: integral and modular.

[0004] Existing integrated heaters, such as the monocrystalline silicon thermal field heater disclosed in CN222613538U, typically employ a one-piece molding process for their main heating coil, using graphite bolts or carbon-carbon bolts only for fixing it to the electrode feet. This type of heater suffers from two major drawbacks: 1. Maintenance and cost defects: The main heating coil is an integral structure. If a local area is damaged due to silicon vapor corrosion, aging, or thermal stress concentration caused by the use environment, the entire heater will be scrapped and cannot be repaired. In addition, the integral molding structure inevitably has the problem of low raw material utilization in the early machining process, which significantly increases production costs. 2. Large-size compatibility drawbacks: As the hot zone size of Czochralski single crystal furnaces develops towards larger dimensions, the size of the matching heaters also increases, requiring a larger volume of graphite blocks. However, the preparation of large-size isostatic graphite raw materials is difficult, and manufacturers have limited reserves, leading to a significant increase in raw material procurement costs, which further increases the production and application costs of integral heaters.

[0005] To address the shortcomings of monolithic heaters, modular heaters have emerged, such as the main heater disclosed in CN220555727U for reducing the oxygen content of monocrystalline silicon rods. The main heating coil of this type of heater is composed of multiple alternating arc-shaped lobes (such as a first arc-shaped lobe, a second arc-shaped lobe, etc.) forming a ring structure. The arc-shaped lobes are connected and fixed by splicing blocks and bolts, and the top of the L-shaped electrode feet is also connected to the arc-shaped lobes by bolts. Compared to monolithic heaters, modular heaters have two major advantages: Raw material savings: Small-sized graphite blocks can be used to process arc-shaped petals, avoiding the high cost of large-sized blocks. In addition, when local damage occurs, only the corresponding arc-shaped petal needs to be replaced, improving material utilization. Combination flexibility: The number and size of the arc-shaped lobes can be adjusted to adapt to different specifications of thermal fields, reducing the cost of customized production.

[0006] Although modular heaters are structurally superior to integral heaters, existing modular heaters all rely on bolts (graphite bolts or carbon-carbon bolts) to connect the arc-shaped lobes and the electrode feet. However, bolted connections have unavoidable defects in the high-temperature operating environment of single-crystal furnaces, becoming a major cause of heater structural failure, specifically manifested as follows: First, threaded assembly triggers initial cracks: During the assembly process of graphite or carbon-carbon bolts, the threads are prone to chipping when they mesh with the internal and external threads of the heater body's threaded hole, leading to the formation of initial cracks at the heater body's threaded hole. During each heating-cooling thermal cycle of single crystal growth, these initial cracks continue to extend and expand, eventually causing the heater body to break at the threaded connection.

[0007] Secondly, the difference in thermal properties exacerbates the risk of cracking: there are differences in the coefficient of thermal expansion and thermal conductivity between carbon carbon bolts and graphite materials. Under high temperature conditions, the interlayer compressive stress and thermal stress of rapid heating and cooling of carbon carbon bolts and graphite heater bodies are much greater than those of graphite bolts, which further accelerates the cracking of the threaded hole of the heater.

[0008] Third, concentrated heat and stress at bolted connections: The contact resistance at bolted connections is relatively high, which easily leads to localized concentrated heat. At the same time, the threaded structure itself causes stress concentration. Under the combined effect, there is an extremely high risk of localized cracking at the threaded hole of the heater connecting plate (or arc-shaped petal), which seriously shortens the service life of the heater. Utility Model Content

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a boltless monocrystalline silicon heater to solve the above-mentioned problems caused by the bolted connection of existing heaters.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A boltless, modular monocrystalline silicon heater, comprising: The main heating ring is used for conductive heating and to provide heat to the quartz crucible. The main heating ring is a ring structure formed by multiple heating plates connected end to end by a tenon and mortise structure. The heating plates are provided with several first and second recesses arranged alternately in the circumferential direction. A foot plate connecting area is provided on one side of the heating plate. At least one foot plate protrusion is provided in the foot plate connecting area. Multiple foot plate protrusions are evenly distributed in the foot plate connecting area. Preferably, there are 1-3 foot plate protrusions. The electrode foot plate is used to connect the single crystal furnace electrode and conduct current to the main heating coil. The upper end of the electrode foot plate is provided with a foot plate groove that matches the foot plate boss. The foot plate boss and the foot plate groove form a mortise and tenon structure.

[0011] Furthermore, the heating element includes a first heating element and a second heating element, which are alternately connected end to end; the tenon structure includes heating element grooves at both ends of the first heating element and heating element bosses at both ends of the second heating element, with the heating element grooves and heating element bosses engaging with each other; the foot plate bosses are provided on the first heating element or the second heating element.

[0012] Furthermore, the multiple heating elements adopt the same structure. One end of the heating element is provided with a heating element boss, and the other end of the heating element is provided with a heating element groove. Adjacent heating elements are connected by the engagement of the heating element boss and the heating element groove. There are at least two electrode feet. When there are two electrode feet, the two electrode feet are connected to the single crystal furnace electrode. When there are more than two electrode feet, the remaining electrode feet are used to support the main heating coil.

[0013] Furthermore, the included angle between the inner wall of the heating element groove and the end face of the heating element is 60°-85°, and the included angle between the side wall of the heating element boss and the end face of the heating element is 60°-85°, so that the first tenon structure is a dovetail groove structure; the second tenon structure is also a dovetail tenon structure.

[0014] Furthermore, the corners of the heating element groove, heating element boss, foot plate groove, and foot plate boss are all rounded.

[0015] Furthermore, there are assembly gaps between the heating element groove and the heating element boss, as well as between the foot plate boss and the foot plate groove, and the assembly gaps are filled with graphite glue.

[0016] Furthermore, the width of the assembly gap is 0.05mm-0.3mm.

[0017] Furthermore, the sidewalls of the heating element groove and the heating element boss, as well as the sidewalls of the foot plate groove and the foot plate boss, are provided with draft surfaces, and the wide end of the draft surface is located at the upper part, while the narrow end of the draft surface is located at the lower part.

[0018] Furthermore, the draft angle of the draft surface is 0.05°-0.5°.

[0019] The beneficial effects of this utility model are: (1) The multiple heating elements of this utility model and the connection between the heating elements and the electrode foot plate are all connected by mortise and tenon structure, which solves the risk of thermal stress concentration caused by the difference in thermal expansion coefficient of graphite or carbon bolts under high temperature environment due to the traditional bolt connection method, which in turn leads to tooth breakage and initial cracks.

[0020] (2) The dovetail tenon structure ensures the tightness of the connection between adjacent heating elements and between the heating elements and the electrode foot plate, thus ensuring the reliability and stability of the heater splicing.

[0021] (3) By setting rounded corners at the corners of the heating plate groove, heating plate boss, foot plate groove and foot plate boss, structural failures such as graphite fracture and edge chipping caused by stress concentration at sharp corners after assembly are avoided.

[0022] (4) By setting assembly gaps between the heating element groove and the heating element boss and between the foot plate boss and the foot plate groove, and filling the assembly gaps with graphite glue, the strength of the heater splicing connection is enhanced.

[0023] (5) Draft surfaces are provided on the side walls of the heating element groove and heating element boss, as well as the side walls of the foot plate groove and foot plate boss. The wide end of the draft surface is set at the upper part and the narrow end of the draft surface is set at the lower part. This not only reduces the difficulty of assembling the heating element, but also prevents the heating element from slipping off after the graphite glue fails, further enhancing the stability and safety of the heater during use. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of Example 1 of a boltless splicing monocrystalline silicon heater.

[0025] Figure 2 This is a schematic diagram of the structure of the first heating element in Example 1.

[0026] Figure 3 This is a partial top view of the first heating element in Example 1.

[0027] Figure 4 This is a schematic diagram of the structure of the second heating element in Example 1.

[0028] Figure 5 This is a partial bottom view of the second heating element in Example 1.

[0029] Figure 6 This is a schematic diagram of the electrode foot plate structure.

[0030] Figure 7 This is a schematic diagram of the structure of Example 2 of a boltless splicing monocrystalline silicon heater.

[0031] Figure 8 This is a schematic diagram of the heating element structure in Example 2.

[0032] In the figure, 1 is the heating element; 11 is the first recess; 12 is the second recess; 13 is the heating element groove; 14 is the foot plate boss; 15 is the heating element boss; 16 is the rounded corner; 2 is the electrode foot plate; 21 is the foot plate groove. Detailed Implementation

[0033] The following will be combined with the appendix Figures 1-8 The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0034] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] Example 1 like Figure 1 As shown, a boltless, spliced ​​single-crystal silicon heater includes a main heating coil and electrode feet 2. The main heating coil is used for conductive heating and to provide heat to the quartz crucible. The main heating coil is composed of multiple heating elements 1 connected end-to-end by a tenon and mortise structure to form a ring structure, as shown. Figure 2 , Figure 4 As shown, the heating element 1 has several alternating first recesses 11 and second recesses 12 arranged vertically in the circumferential direction; as Figure 2 As shown, a foot plate connecting area is provided on one side of the heating element 1, and at least one foot plate protrusion 14 is provided in the foot plate connecting area. Multiple foot plate protrusions 14 are evenly distributed in the foot plate connecting area. Preferably, there are 1-3 foot plate protrusions 14. In this embodiment, there is 1 foot plate protrusion 14.

[0036] Electrode foot plate 2 is used to connect the single crystal furnace electrode and conduct current to the main heating coil, such as... Figure 1 As shown, in this embodiment, there are two electrode feet 2, and the two electrode feet 2 are connected to the single crystal furnace electrode.

[0037] like Figure 6As shown, the upper end of the electrode foot plate 2 is provided with a foot plate groove 21 that cooperates with the foot plate boss 14. The foot plate boss 14 and the foot plate groove 21 form a mortise and tenon structure.

[0038] Compared to traditional bolted connections, this method eliminates the need for additional bolts and other fasteners, reducing the number of parts and manufacturing costs. It also avoids cracks caused by bolt assembly, and more importantly, it prevents concentrated heat and stress at bolted connections, ensuring the reliability and stability of the heater.

[0039] like Figures 2-5 As shown, the heating element 1 includes a first heating element and a second heating element, which are connected end to end alternately; the tenon structure includes heating element grooves 13 at both ends of the first heating element and heating element bosses 15 at both ends of the second heating element, and the heating element grooves 13 and heating element bosses 15 engage with each other; the foot plate bosses 14 are provided on the first heating element or the second heating element.

[0040] like Figure 3 , Figure 5 As shown, the angle between the inner wall of the heating element groove 13 and the end face of the heating element 1 is 60°-85°, and the angle between the side wall of the heating element boss 15 and the end face of the heating element 1 is 60°-85°, making the first tenon structure a dovetail groove structure; the second tenon structure is also a dovetail tenon structure.

[0041] The dovetail tenon structure ensures the tightness of the connection between adjacent heating elements and between the heating elements and electrode foot plate 2, thus ensuring the reliability and stability of the heater assembly.

[0042] like Figure 3 , Figure 5 As shown, the corners of the heating plate groove 13, heating plate boss 15, foot plate groove 21 and foot plate boss 14 are all provided with rounded corners 16, which avoids structural failures such as fracture and chipping of graphite (a hard and brittle material) caused by stress concentration at sharp corners after assembly.

[0043] Assembly gaps are provided between the heating element groove 13 and the heating element boss 15, and between the foot plate boss 14 and the foot plate groove 21. The assembly gaps are filled with graphite adhesive. Before the heater is assembled, a certain thickness of graphite adhesive is evenly applied to the mating surfaces of the heating element groove 13 and the heating element boss 15, as well as the foot plate boss 14 and the foot plate groove 21. After assembly, the heater is placed in an oven to cure the graphite adhesive. Then, electricity is applied to heat the graphite adhesive to carbonize it. The graphite adhesive overflowing from the assembly gaps is then ground off to complete the production of the boltless splicing heater. The graphite adhesive enhances the strength of the heater splicing connection and the continuity of electrical conductivity.

[0044] The width of the assembly gap is 0.05mm-0.3mm.

[0045] like Figure 3 , Figure 5 As shown, the side walls of the heating element groove 13 and heating element boss 15, as well as the side walls of the foot plate groove 21 and foot plate boss 14, are all provided with draft surfaces. The wide end of the draft surface is located at the upper part, and the narrow end of the draft surface is located at the lower part. This draft surface structure not only avoids repeated adjustments and collisions caused by inaccurate alignment of the boss and groove, reducing the difficulty of heating element assembly and improving assembly efficiency, but also prevents the heating element from slipping off after the graphite adhesive fails, further enhancing the stability and safety of the heater during use.

[0046] The draft angle of the draft surface is 0.05°-0.5°.

[0047] Example 2 Unlike Example 1, as Figure 8 As shown, in this embodiment, there are three foot plate protrusions 14, and the multiple heating elements 1 adopt the same structure. One end of each heating element 1 is provided with a heating element protrusion 15, and the other end is provided with a heating element groove 13. Adjacent heating elements are connected by the engagement of the heating element protrusion 15 and the heating element groove 13. At least two electrode foot plates 2 are provided, such as... Figure 7 As shown, in this embodiment, there are four electrode feet 2, two of which are connected to the single crystal furnace electrode, and the remaining electrode feet 2 are used to support the main heating coil to enhance the stability and load-bearing capacity of the heater.

[0048] Heating elements with the same structure have good interchangeability. When a heating element is damaged, it can be easily replaced with a new heating element of the same structure, which reduces maintenance difficulty and cost.

[0049] The above content is merely an example and illustration of the structure of this utility model. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the structure of the utility model, they should all fall within the protection scope of this utility model.

Claims

1. A boltless spliced single crystal silicon heater characterized by, include: The main heating ring is used to conduct electricity and generate heat to provide heat to the quartz crucible. The main heating ring is a ring structure formed by connecting multiple heating plates end to end through a tenon and mortise structure. The heating plates are provided with several first and second recesses arranged alternately in the circumferential direction. A foot plate connecting area is provided on one side of the heating plate. At least one foot plate protrusion is provided in the foot plate connecting area, and multiple foot plate protrusions are evenly distributed in the foot plate connecting area. The electrode foot plate is used to connect the single crystal furnace electrode and conduct current to the main heating coil. The upper end of the electrode foot plate is provided with a foot plate groove that matches the foot plate boss. The foot plate boss and the foot plate groove form a mortise and tenon structure.

2. The boltless splicing type single crystal silicon heater according to claim 1, wherein The heating element includes a first heating element and a second heating element, which are alternately connected end to end; the tenon structure includes heating element grooves at both ends of the first heating element and heating element bosses at both ends of the second heating element, with the heating element grooves and heating element bosses engaging with each other; the foot plate bosses are provided on the first heating element or the second heating element.

3. The boltless spliced single crystal silicon heater according to claim 1, wherein, Multiple heating elements adopt the same structure. One end of the heating element is provided with a heating element boss, and the other end of the heating element is provided with a heating element groove. Adjacent heating elements are connected by the engagement of the heating element boss and the heating element groove. There are at least two electrode feet. When there are two electrode feet, the two electrode feet are connected to the single crystal furnace electrode. When there are more than two electrode feet, the remaining electrode feet are used to support the main heating coil.

4. A boltless, spliced ​​monocrystalline silicon heater according to claim 2 or 3, characterized in that, The included angle between the inner wall of the groove of the heating element and the end face of the heating element is 60°-85°, and the included angle between the side wall of the boss of the heating element and the end face of the heating element is 60°-85°, so that the first tenon structure is a dovetail groove structure; the second tenon structure is also a dovetail tenon structure.

5. The boltless splicing type single crystal silicon heater according to claim 2 or 3, characterized in that, The corners of the heating element groove, heating element boss, foot plate groove, and foot plate boss are all rounded.

6. The boltless splicing type single crystal silicon heater according to claim 2 or 3, characterized in that, Assembly gaps are provided between the heating element groove and the heating element boss, as well as between the foot plate boss and the foot plate groove, and the assembly gaps are filled with graphite glue.

7. The boltless spliced single crystal silicon heater according to claim 6, wherein The width of the assembly gap is 0.05mm-0.3mm.

8. The boltless spliced single crystal silicon heater according to claim 4, wherein, The side walls of the heating element groove and heating element boss, as well as the side walls of the foot plate groove and foot plate boss, are all provided with draft surfaces, and the wide end of the draft surface is located at the upper part, while the narrow end of the draft surface is located at the lower part.

9. The boltless spliced single crystal silicon heater according to claim 8, wherein, The draft angle of the draft surface is 0.05°-0.5°.

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