A heater structure for a silicon carbide deposition furnace

Abstract

This utility model discloses a heater structure for a silicon carbide deposition furnace, belonging to the technical field of carbon-based material production equipment. It includes a graphite electrode, an upper connecting plate, heating rods, and a lower connecting plate. Several heating rods are connected between the upper and lower connecting plates and are evenly arranged. The bottom of the graphite electrode is inserted and fixed to the upper connecting plate. A lower graphite ring is provided at the connection between the graphite electrode and the upper connecting plate, and an upper graphite ring is provided at the connection between the heating rod and the upper and lower connecting plates. The outer walls of both the upper and lower graphite rings are concave arc-shaped, forming an arc transition at the connection between the graphite electrode and the upper connecting plate, and at the connection between the heating rod and the upper and lower connecting plates. This utility model solves the problems of uneven heating within the furnace and crystal cracking at right angles of the heater connection.

Description

Technical Field

[0001] This utility model relates to the field of carbon-based material production equipment technology, specifically a heater structure for a silicon carbide deposition furnace. Background Technology

[0002] Silicon carbide possesses excellent physicochemical properties such as high melting point, high hardness, corrosion resistance, and oxidation resistance, thus having broad application prospects. Silicon carbide is typically obtained using chemical vapor deposition (CVD). The deposition furnace used for CVD is a core component of vacuum coating equipment and CVD equipment; depending on the furnace structure, deposition furnaces are classified into horizontal deposition furnaces, vertical deposition furnaces, etc.

[0003] The vertical deposition furnace uses a four-sided heating system, with graphite heaters suspended around the inner wall of the furnace. If the heaters inside the furnace heat unevenly, it will lead to uneven heating within the furnace, thus affecting product quality. Furthermore, the existing heaters are complex to install, have poor repeatability and consistency, and consume a lot of time. The heating system is made of graphite, which is relatively brittle. During the process, silicon carbide crystals will also adhere to the heaters, especially at right-angle transitions where the heaters can easily accumulate thicker crystals, generating significant internal stress. When the stress exceeds the tensile strength limit of the silicon carbide crystals at that temperature, it will cause the crystals to crack. The fragmented crystals scattered on the substrate will severely affect product quality. Utility Model Content

[0004] This invention overcomes the shortcomings of the prior art by proposing a heater structure for a silicon carbide deposition furnace, which solves the problems of uneven heating inside the furnace and crystal cracking at the right angle of the heater connection.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: A heater structure for a silicon carbide deposition furnace, wherein the heater structure is generally square, including a graphite electrode, an upper connecting plate, heating rods and a lower connecting plate; a plurality of heating rods are connected between the upper connecting plate and the lower connecting plate; the plurality of heating rods are evenly arranged; the bottom of the graphite electrode is inserted and fixed to the upper connecting plate; A lower graphite ring is provided at the connection between the graphite electrode and the upper connecting plate, and an upper graphite ring is provided at the connection between the heating rod and the upper and lower connecting plates; the outer walls of both the upper and lower graphite rings are concave arc-shaped, so that the connection between the graphite electrode and the upper connecting plate, as well as the connection between the heating rod and the upper and lower connecting plates, form an arc transition.

[0006] Furthermore, the upper and lower connecting plates have the same external structure, both being in the shape of a door; the two symmetrical upper connecting plates are arranged on the upper left and right, and the two symmetrical lower connecting plates are arranged on the lower front and back.

[0007] Furthermore, the upper connecting plate is evenly provided with first connecting holes, and the first connecting holes are provided with threaded structures; the lower connecting plate is evenly provided with second connecting holes, the inner diameter of the second connecting holes is adapted to the outer diameter of the heating rod; and the first connecting holes and the second connecting holes correspond one-to-one.

[0008] Furthermore, the upper end of the heating rod is provided with an external thread, and the upper end of the heating rod is threadedly connected to the first connecting hole of the upper connecting plate; the lower end of the heating rod is inserted into the second connecting hole, and the lower end of the heating rod is provided with an internal thread, and the heating rod is tightened to the second connecting hole by a graphite nut.

[0009] Furthermore, the exposed portion of the graphite nut is chamfered, creating a rounded transition at the connection between the graphite nut and the lower connecting plate.

[0010] Furthermore, a third connection hole is provided at the center of the upper connecting plate, and the bottom of the graphite electrode is inserted into the third connection hole and fixedly connected by graphite screws.

[0011] Furthermore, the exposed portion of the graphite screw has a chamfered structure, creating a rounded transition at the connection between the graphite screw and the upper connecting plate.

[0012] Furthermore, both the upper and lower connecting plates are integral structures.

[0013] The beneficial effects of this utility model compared to the prior art are as follows: 1. The heater structure described in this utility model is simple to install, relying on plane and circumferential positioning and screw tightening, the position is accurate and reliable, reducing errors in the installation process, ensuring the accuracy of heater fit, reducing heater installation and debugging time, and improving the accuracy of repeated installation.

[0014] 2. The heater structure described in this utility model has chamfered structures on the upper graphite ring, lower graphite ring, graphite screw, and graphite nut to eliminate the sharp point effect, thereby reducing the internal stress of each component, avoiding airflow dead zones, solving the problem of crystal breakage at the right angle of the heater connection in the later stage of the process, and ensuring product quality.

[0015] 3. The heater structure of this utility model is symmetrically and uniformly distributed, and the heating inside the furnace is uniform, which is conducive to uniform crystal growth. Attached Figure Description

[0016] Figure 1 This is a three-dimensional model schematic diagram of the heater structure described in this utility model; Figure 2 A cross-sectional view showing the connection between the heating rod, the upper connecting plate, and the upper graphite ring; Figure 3 A cross-sectional schematic diagram showing the connection between the graphite electrode, the upper connecting plate, and the lower graphite ring; Figure 4A cross-sectional schematic diagram showing the connection between the heating rod, the lower connecting plate, and the graphite nut; In the diagram: 1. Graphite electrode; 2. Upper connecting plate; 3. Heating rod; 4. Lower connecting plate; 5. Upper graphite ring; 6. Lower graphite ring; 7. Graphite screw; 8. Graphite nut; 9. First connecting hole; 10. Second connecting hole; 11. Third connecting hole. Detailed Implementation

[0017] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, this utility model will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it. The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0018] See Figures 1 to 4 This embodiment proposes a heater structure for a silicon carbide deposition furnace. The heater structure is generally square and includes a graphite electrode 1, an upper connecting plate 2, a heating rod 3, a lower connecting plate 4, an upper graphite ring 5, a lower graphite ring 6, a graphite screw 7, and a graphite nut 8.

[0019] The upper connecting plate 2 and the lower connecting plate 4 have the same external structure, both being in the shape of a door. The upper connecting plate 2 is evenly provided with first connecting holes 9, and the first connecting holes 9 are provided with threaded structures. The lower connecting plate 4 is evenly provided with second connecting holes 10, and the inner diameter of the second connecting holes 10 is adapted to the outer diameter of the heating rod 3. The two symmetrical upper connecting plates 2 are arranged on the upper left and right, and the two symmetrical lower connecting plates 4 are arranged on the lower front and back, and the first connecting holes 9 and the second connecting holes 10 correspond one-to-one. Several heating rods 3 are connected between the upper connecting plate 2 and the lower connecting plate 4. The upper connecting plate 2 and the lower connecting plate 4 are both designed as a single piece, and the intersecting separate installation is simpler and the structure is more stable and less prone to deformation.

[0020] Specifically, the upper end of the heating rod 3 is provided with external threads, and the upper end of the heating rod 3 is threadedly connected to the first connecting hole 9 of the upper connecting plate 2; the lower end of the heating rod 3 is inserted into the second connecting hole 10, and the lower end of the heating rod 3 is provided with internal threads. The heating rod 3 and the second connecting hole 10 are tightened with graphite nuts 8, thereby fixing the heating rod 3 to the lower connecting plate 4. The connection method between the heating rod 3 and the upper connecting plate 2 and the lower connecting plate 4 is simple and easy to disassemble and assemble, which greatly improves the installation efficiency. The heating rods 3 are evenly spaced and symmetrically distributed, which makes the heating in the furnace uniform and reduces the impact of temperature gradient on the product.

[0021] A third connecting hole 11 is provided at the center of the upper connecting plate 2. The bottom of the graphite electrode 1 is inserted into the third connecting hole 11 and then fixed by the graphite screw 7. This insertion connection method prevents the lower end of the graphite electrode 1 from being directly exposed in the furnace body, increasing the frequency of use of the graphite electrode 1; moreover, this structure is simple to install and has high repeatability, making installation and disassembly simpler.

[0022] A lower graphite ring 6 is provided at the transition point where the graphite electrode 1 connects to the upper connecting plate 2, and an upper graphite ring 5 is provided at the transition point where the heating rod 3 connects to the upper connecting plate 2 and the lower connecting plate 4. The outer walls of both the upper graphite ring 5 and the lower graphite ring 6 are concave arc shapes, so that the connection points between the graphite electrode 1 and the upper connecting plate 2, as well as the connection points between the heating rod 3 and the upper connecting plate 2 and the lower connecting plate 4, form arc transitions.

[0023] The exposed parts of the graphite screw 7 and graphite nut 8 are provided with a chamfer structure, so that the connection between the graphite screw 7 and the upper connecting plate 2 forms an arc transition, and the connection between the graphite nut 8 and the lower connecting plate 4 forms an arc transition.

[0024] Existing deposition furnaces suffer from sharp point effects and uneven temperature fields at right angles in the heaters, and these right angles also act as dead zones for airflow. This leads to faster and more rapid silicon carbide crystal growth at these locations. When abnormally deposited silicon carbide crystals become tightly bonded to the heater surface, the inconsistent expansion and contraction during subsequent heating or cooling processes generates significant internal stress. When this stress exceeds the tensile strength of the silicon carbide crystal at that temperature, it causes the crystal to fracture. The fragmented crystal debris scattered on the substrate severely impacts product quality. The chamfered structure at the connection points in this embodiment improves the uniformity of the thermal field, eliminates sharp points, avoids dead zones for airflow, and allows for cost control by replacing the graphite ring separately.

[0025] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all such deductions or substitutions should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A heater structure for a silicon carbide deposition furnace, characterized in that, The heater structure is generally square, including a graphite electrode (1), an upper connecting plate (2), heating rods (3) and a lower connecting plate (4); several heating rods (3) are connected between the upper connecting plate (2) and the lower connecting plate (4); several heating rods (3) are evenly arranged; the bottom of the graphite electrode (1) is inserted and fixed on the upper connecting plate (2); A lower graphite ring (6) is provided at the connection between the graphite electrode (1) and the upper connecting plate (2), and an upper graphite ring (5) is provided at the connection between the heating rod (3) and the upper connecting plate (2) and the lower connecting plate (4); the outer walls of the upper graphite ring (5) and the lower graphite ring (6) are both concave arc shapes; so that the connection between the graphite electrode (1) and the upper connecting plate (2), and the connection between the heating rod (3) and the upper connecting plate (2) and the lower connecting plate (4) form arc transitions.

2. The heater structure for a silicon carbide deposition reactor of claim 1, wherein The upper connecting plate (2) and the lower connecting plate (4) have the same external structure, both being in the shape of a door; the two symmetrical upper connecting plates (2) are arranged on the upper left and right, and the two symmetrical lower connecting plates (4) are arranged on the lower front and back.

3. The heater structure for a silicon carbide deposition reactor of claim 2, wherein The upper connecting plate (2) is uniformly provided with first connecting holes (9), and the first connecting holes (9) are provided with threaded structures; the lower connecting plate (4) is uniformly provided with second connecting holes (10), the inner diameter of the second connecting holes (10) is adapted to the outer diameter of the heating rod (3); and the first connecting holes (9) and the second connecting holes (10) correspond one-to-one.

4. The heater structure for a silicon carbide deposition reactor of claim 3, wherein The upper end of the heating rod (3) is provided with an external thread, and the upper end of the heating rod (3) is threadedly connected to the first connecting hole (9) of the upper connecting plate (2); the lower end of the heating rod (3) is inserted into the second connecting hole (10), and the lower end of the heating rod (3) is provided with an internal thread. The heating rod (3) and the second connecting hole (10) are tightened by a graphite nut (8).

5. The heater structure for a silicon carbide deposition reactor of claim 4, wherein The exposed part of the graphite nut (8) is provided with a chamfer structure, so that the connection between the graphite nut (8) and the lower connecting plate (4) forms an arc transition.

6. The heater structure for a silicon carbide deposition reactor of claim 3, wherein A third connection hole (11) is provided at the center of the upper connecting plate (2). The bottom of the graphite electrode (1) is inserted into the third connection hole (11) and fixedly connected by a graphite screw (7).

7. The heater structure for a silicon carbide deposition reactor of claim 6, wherein, The exposed part of the graphite screw (7) is provided with a chamfer structure so that the connection between the graphite screw (7) and the upper connecting plate (2) forms an arc transition.

8. The heater structure for a silicon carbide deposition reactor of claim 2, wherein, The upper connecting plate (2) and the lower connecting plate (4) are both integral structures.

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