Medium-high frequency induction heating furnace with combined heat preservation structure

Abstract

The utility model discloses a medium-high frequency induction heating furnace with a combined heat preservation structure, which comprises a furnace shell, a graphite crucible arranged in the furnace shell, a heat preservation layer arranged on the outer side of the graphite crucible, and an induction heating coil arranged between the heat preservation layer and the furnace shell, a high-temperature porcelain pad is arranged between every two adjacent heat preservation cylinders. The heat preservation layer comprises at least two layers of heat preservation cylinders which are concentrically arranged, the sectional area of the single-layer heat preservation cylinder is reduced, the magnetic flux of the single heat preservation layer is reduced, and therefore induced current generated by the heat preservation cylinders is greatly reduced, and the risk of spontaneous heating of the heat preservation layer is reduced. The high-temperature porcelain pad is arranged between the two adjacent heat preservation cylinders, so that the two adjacent layers of heat preservation cylinders are insulated, and large current is prevented from being generated in the heat preservation cylinders.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a medium- and high-frequency induction heating furnace with a combined heat preservation structure. Background Technology

[0002] With the rapid development of the semiconductor industry, the demand for crystal materials is increasing, and the production efficiency and cost of high-temperature heat treatment are receiving more and more attention from the industry. In the production process of crystal materials, medium and high frequency induction heating furnaces are generally used to process the materials.

[0003] Existing induction heating furnaces typically use a single carbon fiber felt wrapped around the outside of a graphite crucible for insulation, often in a single, integral wrapping for ease of fabrication. However, carbon fiber felt is a conductive material; under the influence of the magnetic field generated by the induction coil, a current is induced within the wrapped felt, causing it to self-heat. To prevent this self-heating, existing technologies employ ceramic components to create a circumferential break in the insulation layer. However, since ceramic components cannot withstand temperatures above 2000℃, this insulation structure is unsuitable for medium- to high-frequency induction heating furnaces operating above 2000℃. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the insulation layer of the existing medium-high frequency induction heating furnace with combined insulation structure is prone to self-heating, and a medium-high frequency induction heating furnace with combined insulation structure is provided.

[0005] The technical solution to this problem is: to construct a medium-high frequency induction heating furnace with a combined heat preservation structure, including a furnace shell, a graphite crucible disposed inside the furnace shell, a heat preservation layer disposed outside the graphite crucible, and an induction heating coil disposed between the heat preservation layer and the furnace shell. The heat preservation layer includes at least two concentrically arranged heat preservation cylinders, and a high-temperature ceramic pad is disposed between two adjacent heat preservation cylinders.

[0006] Furthermore, the single-layer insulation cylinder has a vertical gap in the circumferential direction, which can disconnect the conductive path in the circumferential direction of the insulation cylinder, thereby avoiding the generation of self-induced current.

[0007] Furthermore, the vertical gaps between adjacent insulation cylinders are staggered in the circumferential direction to prevent the heat radiation from the crucible from passing directly through the vertical gaps to the furnace shell, which could damage the furnace shell.

[0008] Furthermore, the high-temperature ceramic pads placed between the innermost insulation cylinder and the adjacent insulation cylinders are staggered with the vertical gaps of the innermost insulation cylinder to prevent heat radiation from directly hitting the high-temperature ceramic pads.

[0009] Furthermore, the outermost layer of the insulation layer is reinforced with an insulation cylinder to prevent the insulation layer from collapsing outward and to provide insulation.

[0010] Furthermore, the insulation cylinder reinforcement layer is formed by winding a low thermal conductivity and low electrical conductivity insulation felt along the circumference of the outermost insulation cylinder.

[0011] Furthermore, the insulation cylinder is composed of a combination of carbonaceous insulation felt with low thermal conductivity and low specific heat and insulation felt with low thermal conductivity and low electrical conductivity. The insulation cylinder formed by the combination of materials has both good thermal insulation properties and reduced electrical conductivity.

[0012] Furthermore, the low thermal conductivity and low specific heat carbonaceous insulation felt is a soft carbon felt, and the low thermal conductivity and low electrical conductivity insulation felt is a ceramic fiber felt.

[0013] Furthermore, the graphite crucible is composed of an upper graphite cylinder and a lower graphite cylinder joined together, and the joint between the upper and lower graphite cylinders is provided with mutually cooperating sealing steps.

[0014] The medium-high frequency induction heating furnace with a combined insulation structure described in this utility model has the following beneficial effects: By setting the insulation layer including at least two concentrically arranged insulation cylinders, the cross-sectional area of ​​a single insulation cylinder is reduced, and the magnetic flux of a single insulation layer is lowered, thereby significantly reducing the induced current generated by the insulation cylinder and reducing the risk of self-heating of the insulation layer. By setting a high-temperature ceramic pad between two adjacent insulation cylinders, insulation is achieved between the two adjacent insulation cylinders, preventing the generation of large currents within the insulation cylinders. Furthermore, by setting a vertical gap in the circumferential direction of a single insulation cylinder, the conductive path in the circumferential direction of the insulation cylinder is broken, thereby preventing the generation of self-induced current within the insulation cylinder and further reducing the risk of self-heating of the insulation layer. Attached Figure Description

[0015] Figure 1 The image shown is a front view of a preferred embodiment of the medium-high frequency induction heating furnace with a combined heat preservation structure according to this utility model.

[0016] Figure 2 As shown Figure 1 AA section view;

[0017] Figure 3 As shown Figure 2 Enlarged view of part I. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] It should also be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 simplifying the description, 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.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] like Figure 1 , 2 As shown in Figure 3, in a preferred embodiment of the medium-high frequency induction heating furnace with a combined insulation structure described in this utility model, it mainly includes a furnace shell 10, a graphite crucible 1 disposed inside the furnace shell, an insulation layer 20 disposed outside the graphite crucible, and an induction heating coil 2 disposed between the insulation layer 20 and the furnace shell 10. The insulation layer 20 comprises at least two concentrically arranged insulation cylinders. In this preferred embodiment, the insulation layer 20 preferably comprises two insulation cylinders: an inner insulation cylinder 21 and an outer insulation cylinder 22. A gap 23 is provided between adjacent insulation cylinders, and a high-temperature ceramic pad 24 is disposed within the gap 23 to separate the two insulation cylinders and prevent the formation of a large-scale induced current. The induction heating coil 2 is connected to an external medium-high frequency AC power supply to provide sufficient electromagnetic field to the graphite crucible 1 to achieve induction heating. The graphite crucible 1 is cylindrical and located in the central region of the induction heating coil 2.

[0022] In this preferred embodiment, a vertical gap 25 is preferably provided in the circumferential direction of the single-layer insulation cylinders 21 and 22, and the vertical gap 25 extends through the entire insulation cylinder. Preferably, the vertical gaps 25 of adjacent insulation cylinders are staggered in the circumferential direction to prevent the heat of the graphite crucible 1 from directly radiating to the furnace shell 10, thus protecting the furnace shell.

[0023] To prevent the heat from the graphite crucible 1 from directly hitting the high-temperature ceramic pad 24, it is preferable to stagger the vertical gaps between the innermost insulating cylinder and the high-temperature ceramic pad between the innermost insulating cylinder and the adjacent insulating cylinder, that is, the high-temperature ceramic pad 24 between the inner insulating cylinder 21 and the outer insulating cylinder 22 avoids the vertical gap of the inner insulating cylinder 21.

[0024] In this preferred embodiment, a thermal insulation cylinder reinforcement layer 26 is preferably provided on the outermost side of the thermal insulation layer to prevent the thermal insulation layer 20 from collapsing outward. This thermal insulation cylinder reinforcement layer 26 is preferably formed by winding a low thermal conductivity and low electrical conductivity thermal insulation felt along the circumference of the outermost thermal insulation cylinder. This low thermal conductivity and low electrical conductivity thermal insulation felt can be a ceramic fiber felt.

[0025] In the above embodiments, the insulation cylinder 20 is preferably constructed by stacking a combination of carbonaceous insulation felt with low thermal conductivity and low specific heat and insulation felt with low thermal conductivity and low electrical conductivity. The carbonaceous insulation felt with low thermal conductivity and low specific heat can be soft carbon felt, and the insulation felt with low thermal conductivity and low electrical conductivity can be ceramic fiber felt. The insulation cylinder formed by using these two combined materials has good thermal insulation properties while reducing the overall electrical conductivity of the insulation cylinder.

[0026] In the above embodiments, when processing large-sized workpieces, the graphite crucible needs to have a large height, but large-sized graphite crucibles cannot be formed in one step. The graphite crucible can be configured to be composed of an upper graphite cylinder 1a and a lower graphite cylinder 1b, to reduce manufacturing costs; and preferably, a mutually cooperating sealing step 1c is provided at the joint between the upper and lower graphite cylinders.

[0027] Based on the embodiments of this utility model, any modifications, equivalent substitutions, improvements, etc., made by all other embodiments obtained by those skilled in the art without creative effort should be included within the protection scope of this utility model.

Claims

1. A medium-high frequency induction heating furnace with a combined insulation structure, comprising a furnace shell, a graphite crucible disposed within the furnace shell, an insulation layer disposed outside the graphite crucible, and an induction heating coil disposed between the insulation layer and the furnace shell, characterized in that, The heat preservation layer comprises at least two concentrically arranged heat preservation cylinders, and high-temperature porcelain pads are arranged between adjacent heat preservation cylinders.

2. The medium-high frequency induction heating furnace with the combined heat retaining structure according to claim 1, characterized in that, The single-layer heat preservation cylinder is provided with vertical gaps in the circumferential direction.

3. The medium-high frequency induction heating furnace with the combined heat retaining structure according to claim 2, characterized in that, The vertical gaps of adjacent two layers of heat preservation cylinders are staggered in the circumferential direction.

4. The medium-high frequency induction heating furnace with the combined heat retaining structure according to claim 3, characterized in that, The high-temperature porcelain pad arranged between the innermost heat preservation cylinder and the adjacent heat preservation cylinder is staggered with the vertical gap of the innermost heat preservation cylinder.

5. The medium-high frequency induction heating furnace with the combined heat retaining structure according to claim 3, characterized in that, The outermost side of the heat preservation layer is further provided with a heat preservation cylinder reinforcing layer.

6. The medium-high frequency induction heating furnace with the combined heat retaining structure according to claim 5, characterized in that, The heat preservation cylinder reinforcing layer is formed by winding low-thermal-conductivity and low-electric-conductivity heat preservation felt along the circumferential direction of the outermost heat preservation cylinder.

7. The medium-high frequency induction heating furnace with the combined heat retaining structure according to any one of claims 1 to 6, characterized in that, The graphite crucible is formed by splicing an upper graphite cylinder and a lower graphite cylinder, and the splicing positions of the upper graphite cylinder and the lower graphite cylinder are provided with mutually matched sealing steps.

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