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

Abstract

The invention 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] The invention relates to the field of semiconductor technology, and in particular to a medium-high frequency induction heating furnace with a combined thermal insulation structure. Background Art

[0002] With the rapid development of the semiconductor industry, the demand for crystal materials is becoming more and more vigorous, and the production efficiency and cost of high-temperature heat treatment are increasingly valued by the industry. In the production process of crystal materials, medium and high frequency induction heating furnaces are generally used to process and produce materials.

[0003] The insulation layer of the existing induction heating furnace is usually realized by winding a single carbon fiber felt around the outside of a graphite crucible, and for the convenience of manufacturing, an integral carbon fiber felt is usually used for wrapping and winding. However, carbon fiber felt is a conductive material. Under the action of the magnetic field generated by the induction coil, a certain current will be generated in the wrapped carbon fiber felt, causing the carbon fiber felt to self-heat. In order to avoid the self-heating of the insulation material, the prior art has used porcelain parts to separate the insulation layer in the circumferential direction, making it discontinuous in the circumferential direction. Since porcelain parts cannot withstand high temperatures above 2000°C, this insulation structure cannot be used in medium and high frequency induction heating furnaces above 2000°C. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a medium-high frequency induction heating furnace with a combined insulation structure in view of the problem that the insulation layer of the medium-high frequency induction heating furnace with a combined insulation structure in the prior art is prone to self-heating.

[0005] The technical solution to the technical problem of the present invention is: constructing a medium-high frequency induction heating furnace with a combined insulation structure, including a furnace shell, a graphite crucible arranged in the furnace shell, an insulation layer arranged outside the graphite crucible, and an induction heating coil arranged between the insulation layer and the furnace shell, the insulation layer includes at least two layers of insulation tubes arranged concentrically, and a high-temperature ceramic pad is provided between two adjacent insulation tubes.

[0006] Furthermore, the single-layer heat-insulating cylinder is provided with a vertical gap in the circumferential direction, which can disconnect the conductive path in the circumferential direction of the heat-insulating cylinder, thereby avoiding the generation of self-inductance current.

[0007] Furthermore, the vertical gaps between two adjacent layers of insulation tubes are staggered in the circumferential direction to prevent the heat radiation of the crucible from passing through the vertical gap directly to the furnace shell, thereby damaging the furnace shell.

[0008] Furthermore, the high-temperature ceramic pad provided between the innermost circle insulation tube and the adjacent insulation tube and the vertical gap between the innermost circle insulation tube are staggered to avoid direct heat radiation to the high-temperature ceramic pad.

[0009] Furthermore, a heat-insulating tube reinforcement layer is provided on the outermost side of the heat-insulating layer to prevent the heat-insulating layer from collapsing outwards and also to play a heat-insulating role.

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

[0011] Furthermore, the insulation tube is formed by stacking a combination of a carbon insulation felt with low thermal conductivity and low specific heat and an insulation felt with low thermal conductivity and low electrical conductivity. The insulation tube formed by the combined material has good thermal insulation properties and reduces the electrical conductivity of the insulation tube.

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

[0013] Furthermore, the graphite crucible is formed by splicing an upper graphite tube and a lower graphite tube, and a sealing step that cooperates with each other is provided at the splicing position of the upper graphite tube and the lower graphite tube.

[0014] The implementation of the medium-high frequency induction heating furnace with a combined insulation structure described in the present invention has the following beneficial effects: by providing an insulation layer including at least two layers of insulation tubes arranged concentrically, the cross-sectional area of ​​a single-layer insulation tube is reduced, and the magnetic flux of a single insulation layer is reduced, thereby greatly reducing the induced current generated by the insulation tube and reducing the risk of self-heating of the insulation layer. By providing a high-temperature ceramic pad between two adjacent insulation tubes, insulation is provided between the two adjacent insulation tubes to avoid the generation of large currents in the insulation tubes. Furthermore, by providing a vertical gap in the circumferential direction of a single-layer insulation tube, the conductive path in the circumferential direction of the insulation tube is disconnected, thereby avoiding the generation of self-induced current in the insulation tube and further reducing the risk of self-heating of the insulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure shows a front view of a preferred embodiment of a medium-high frequency induction heating furnace with a combined heat-insulating structure according to the present invention;

[0016] Figure 2 Shown Figure 1 AA section view;

[0017] Figure 3 Shown Figure 2 Enlarged view of part I. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] It should also be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] like Figure 1 , 2 As shown in Figure 3, in the preferred embodiment of the medium-high frequency induction heating furnace with a combined insulation structure of the present invention, it mainly includes a furnace shell 10, a graphite crucible 1 arranged in the furnace shell, an insulation layer 20 arranged outside the graphite crucible, and an induction heating coil 2 arranged between the insulation layer 20 and the furnace shell 10. The insulation layer 20 includes at least two layers of insulation tubes arranged concentrically. In this preferred embodiment, the insulation layer 20 preferably includes two layers of insulation tubes, namely an inner insulation tube 21 and an outer insulation tube 22. A gap 23 is provided between the two adjacent insulation tubes. A high-temperature ceramic pad 24 is provided in the gap 23 to separate the two insulation tubes to prevent the formation of a large range of induced current. The induction heating coil 2 is connected to an external medium-high frequency AC power supply to provide a sufficient electromagnetic field to the graphite crucible 1 to achieve induction heating. The graphite crucible 1 is configured to be cylindrical and located in the central area of ​​the induction heating coil 2.

[0022] In this preferred embodiment, vertical gaps 25 are preferably provided in the circumferential direction of the single-layer insulation tubes 21 and 22, and the vertical gaps 25 run through the entire insulation tube. The vertical gaps 25 of two adjacent insulation tubes are preferably staggered in the circumferential direction to prevent the heat of the graphite crucible 1 from being directly radiated to the furnace shell 10, thereby protecting the furnace shell.

[0023] In order to prevent the heat of the graphite crucible 1 from directly irradiating the high-temperature ceramic pad 24, it is preferred to stagger the vertical gap between the innermost insulation tube and the high-temperature ceramic pad between the adjacent insulation tube and the innermost insulation tube, that is, the high-temperature ceramic pad 24 between the inner insulation tube 21 and the outer insulation tube 22 avoids the vertical gap of the inner insulation tube 21.

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

[0025] In the above embodiment, it is preferred that the insulation tube 20 is formed by stacking a carbon insulation felt with low thermal conductivity and low specific heat and an insulation felt with low thermal conductivity and low electrical conductivity. The carbon insulation felt with low thermal conductivity and low specific heat can be a soft carbon felt, and the insulation felt with low thermal conductivity and low electrical conductivity can be a ceramic fiber felt. The insulation tube formed by the two combined materials has good thermal insulation performance and reduces the electrical conductivity of the entire insulation tube.

[0026] In the above embodiment, when a large-sized workpiece needs to be processed, the graphite crucible needs to have a larger height dimension, but a large-sized graphite crucible cannot be formed and processed at one time. The graphite crucible can be configured to be spliced ​​by an upper graphite tube 1a and a lower graphite tube 1b to reduce the manufacturing cost; and preferably, a sealing step 1c that cooperates with each other is provided at the splicing of the upper graphite tube and the lower graphite tube.

[0027] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work, any modifications, equivalent substitutions, improvements, etc. made should be included in the protection scope of the present invention.

Claims

1. A medium-high frequency induction heating furnace with a combined insulation structure, comprising a furnace shell, a graphite crucible arranged in the furnace shell, an insulation layer arranged outside the graphite crucible, and an induction heating coil arranged between the insulation layer and the furnace shell, characterized in that: The heat-insulating layer comprises at least two layers of heat-insulating tubes which are arranged concentrically, and a high-temperature ceramic pad is arranged between two adjacent heat-insulating tubes.

2. The medium-high frequency induction heating furnace with a combined insulation structure according to claim 1, characterized in that: The single-layer heat-insulating cylinder is provided with a vertical gap in the circumferential direction.

3. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 2, characterized in that: The vertical gaps between two adjacent layers of thermal insulation tubes are staggered in the circumferential direction.

4. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 3, characterized in that: The high-temperature ceramic pad arranged between the innermost circle insulation tube and the adjacent insulation tube and the vertical gap between the innermost circle insulation tube are staggered.

5. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 3, characterized in that: The outermost side of the thermal insulation layer is also provided with a thermal insulation tube reinforcement layer.

6. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 5, characterized in that: The insulation tube reinforcement layer is formed by winding a low thermal conductivity and low electrical conductivity insulation felt along the circumferential direction of the outermost insulation tube.

7. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to any one of claims 1 to 6, characterized in that: The heat-insulating tube is formed by stacking a combination of a carbon heat-insulating felt with low heat conductivity and low specific heat and a heat-insulating felt with low heat conductivity and low electrical conductivity.

8. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 7, characterized in that: The carbon insulation felt with low thermal conductivity and low specific heat is soft carbon felt, and the low thermal conductivity and low electrical conductivity insulation felt is ceramic fiber felt.

9. The medium-high frequency induction heating furnace with a combined thermal insulation structure according to claim 7, characterized in that: The graphite crucible is formed by splicing an upper graphite tube and a lower graphite tube, and a sealing step that cooperates with each other is provided at the splicing position of the upper graphite tube and the lower graphite tube.

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