A new type of induction heating structure

Abstract

The present invention relates to the technical field of silicon carbide crystal growth equipment. A novel induction heating structure comprises a heater body, the heater body comprises a coil assembly and a mounting base supporting the coil assembly, the mounting base is mounted in a silicon carbide crystal growth furnace through a centering structure; the centering structure comprises an outwardly convex positioning step arranged on the lower side of the mounting base and an inwardly concave step hole provided at the center of the silicon carbide crystal growth furnace, the step hole is used to embed the positioning step; the mounting base is provided with circumferentially arranged waist-shaped holes, the mounting base is fixed in the silicon carbide crystal growth furnace by screws passing through the waist-shaped holes; an upwardly extending hollow column is fixed on the mounting base; the coil assembly comprises a supporting foot, the supporting foot is provided with a through hole through which an adjusting screw is passed, the bottom of the adjusting screw is threadedly connected to the hollow column, and the top of the adjusting screw is threadedly connected to a locking nut. The present invention realizes rapid centering installation and position adjustment of the coil assembly through the centering structure.

Description

Technical Field

[0001] The invention relates to the field of silicon carbide crystal growth equipment, in particular to a silicon carbide furnace heater. Background Art

[0002] The silicon carbide furnace uses physical vapor transport (PVT) to grow crystals. Under certain atmosphere and pressure conditions, silicon carbide raw materials are added to the graphite crucible, heated at high temperature to sublimate, and then transported to the growth seed crystal for condensation and crystallization. The crucible can be rotated in the coil, and the coil can be raised and lowered relative to the thermal field to adjust its position to match the temperature field.

[0003] The heater is the main component of the silicon carbide crystal growth furnace. With the vigorous development of the semiconductor industry, semiconductor materials have evolved from the first generation to the current third generation. The first generation of semiconductor materials, represented by silicon, has a power of about 100W, but a frequency of only about 3GHz; the second generation, represented by gallium arsenide, has a power of less than 100W, but a frequency of up to 100GHz. Therefore, the first two generations of semiconductor materials are more complementary to each other. The third generation of semiconductors, represented by gallium nitride and silicon carbide, can have a power of more than 1000W and a frequency close to 100GHz, with obvious advantages.

[0004] The heater of the existing silicon carbide crystal growth furnace has the following defects:

[0005] 1) Complex structure, difficult installation, time-consuming debugging and low efficiency;

[0006] 2) It is difficult to center the heater in the furnace, and the height deviation makes it difficult to connect with the electrode;

[0007] 3) It is inconvenient to disassemble when connected to the electrode;

[0008] 4) The vacuum seal is not very good after docking with the electrode, which affects the overall vacuum leak detection of the equipment. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a novel induction heating structure to solve at least one of the above technical problems.

[0010] In order to achieve the above object, the present invention provides a novel induction heating structure, comprising a heater body, wherein the heater body comprises a coil assembly and a mounting base supporting the coil assembly, wherein the mounting base is mounted in a silicon carbide crystal growth furnace through a centering structure;

[0011] The centering structure includes an outwardly protruding positioning step arranged on the lower side of the mounting base and an inwardly concave step hole opened at the center of the silicon carbide crystal growth furnace, wherein the step hole is used to embed the positioning step;

[0012] The mounting base is provided with waist-shaped holes arranged circumferentially, and the mounting base is fixed in the silicon carbide crystal growth furnace by screws passing through the waist-shaped holes;

[0013] A hollow column extending upward is fixed on the mounting base;

[0014] The coil assembly includes a supporting foot, the supporting foot is provided with a through hole for passing an adjusting screw, the bottom of the adjusting screw is threadedly connected to the hollow column, and the top of the adjusting screw is threadedly connected to a locking nut.

[0015] The present invention realizes the rapid centering installation of the coil assembly through the centering structure. The waist-shaped hole facilitates the adjustment of the circumferential angle position of the coil assembly. The connection structure of the coil assembly and the mounting base is optimized to facilitate the adjustment of the height of the heater. The height is adjusted to align with the electrode mounting hole on the side of the furnace body, and the horizontal position of the heater can also be adjusted to the required accuracy.

[0016] Further preferably, the coil assembly further comprises at least three circumferentially arranged ceramic columns, and the bottom of each ceramic column is detachably connected to the supporting foot;

[0017] The ceramic column is provided with a coil positioning and mounting hole;

[0018] The coil assembly comprises a coil, a copper stud is fixed on the coil, and the copper stud passes through the coil positioning installation hole and is locked and fixed by a copper nut.

[0019] Ensure the turn spacing of the coil so that the heat it emits is uniform.

[0020] Further preferably, the coil assembly further includes a copper electrode arranged outside the silicon carbide crystal growth furnace;

[0021] The copper electrode is detachably connected to the coil.

[0022] Easy to assemble.

[0023] Further preferably, a connecting flange is welded and fixed to the end of the coil;

[0024] A sealing ring is provided between the copper electrode and the connecting flange to ensure that the vacuum and cooling water do not leak.

[0025] It also includes a clamp, which clamps and fixes the copper electrode and the connecting flange.

[0026] Convenient for detachable setting of copper electrodes and coils.

[0027] Further preferably, the clamp comprises two clamping members arranged opposite to each other, and the clamping members are detachably connected by bolts.

[0028] Further preferably, the inner wall of the clamping member is provided with a slot having a trapezoidal cross section that is wide inside and narrow outside;

[0029] The outer structure after the copper electrode and the connecting flange are assembled matches the slot.

[0030] Further preferably, a water-cooling flange is installed on the side wall of the silicon carbide crystal growth furnace, and the copper electrode extends out of the silicon carbide crystal growth furnace from the water-cooling flange;

[0031] A sealing structure is provided between the copper electrode and the water-cooling flange.

[0032] Further preferably, the sealing structure comprises an insulating sleeve, a sealing flange, a flange sealing ring and an electrode sealing ring;

[0033] The sealing flange is detachably connected to the water-cooling flange, and the flange sealing ring is installed between the sealing flange and the water-cooling flange;

[0034] The sealing flange is sleeved on the periphery of the copper electrode, and the electrode sealing ring is installed between the sealing flange and the copper electrode;

[0035] The insulating sleeve is fixed on the copper electrode, and the inner side of the sealing flange abuts against the outer side of the insulating sleeve;

[0036] The insulating sleeve is inserted into the mounting hole on the water-cooling flange.

[0037] Further preferably, the sealing flange is made of Teflon.

[0038] Further preferably, two mounting holes for inserting insulating sleeves are provided on the water-cooling flange, and the two mounting holes are used for extending copper electrodes connected to both ends of the coil.

[0039] Beneficial effects:

[0040] 1) Its structure is easy to install, easy to adjust the level and height, and easier to connect with the electrode outside the furnace. It is a new type of heater structure and has been applied in actual production in batches.

[0041] 2) The position of the coil can be adjusted in multiple dimensions. A positioning step is designed under the furnace chassis, and the coil base is directly positioned in the center of the furnace bottom; a circumferential waist hole and three cylinders with internal threads are designed within the circumference of the coil base to facilitate the adjustment of the angle and height of the heater in the horizontal circumferential direction; the three supporting feet of the heater are designed with height-adjustable adjustment axes to facilitate the adjustment of the horizontal height of the heater.

[0042] 3) The coil is evenly distributed with studs, which are fixed and supported by copper nuts and three ceramic columns.

[0043] 4) The coil and the copper electrode are connected by a clamp, and the sealing surface is designed with an O-ring, which can prevent the internal cooling water from leaking and ensure vacuum sealing, and is easy to install and disassemble. A ceramic insulating sleeve and an O-ring are designed between the copper electrode and the sealing flange, and the copper electrode can be easily disassembled from the entire vacuum chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a cross-sectional view in the axial direction of the specific embodiment 1 of the present invention;

[0045] Figure 2 A cross-sectional view in the radial direction of a specific embodiment 1 of the present invention;

[0046] Figure 3 This is a cross-sectional view of the connection between the coil and the copper electrode in specific embodiment 1 of the present invention.

[0047] Among them: 1 is a silicon carbide crystal growth furnace; 3 is a mounting base; 4 is an adjusting screw; 5 is a supporting foot; 6 is a locking nut; 7 is a ceramic column; 8 is a coil; 9 is a copper nut; 10 is a screw; 11 is a copper electrode; 12 is a clamp; 13 is a sealing ring; 14 is an insulating sleeve; 15 is a water-cooling flange; 16 is a flange sealing ring; 17 is an electrode sealing flange; 18 is an electrode sealing ring. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings.

[0049] Specific embodiment 1, see Figures 1 to 3A novel induction heating structure includes a heater body, the heater body includes a coil assembly and a mounting base 3 supporting the coil assembly, the mounting base 3 is installed in a silicon carbide crystal growth furnace 1 through a centering structure; the centering structure includes an outward convex positioning step arranged on the lower side of the mounting base 3 and an inward concave step hole provided at the center of the silicon carbide crystal growth furnace 1, the step hole is used to embed the positioning step; the mounting base 3 is provided with waist-shaped holes arranged circumferentially, the mounting base 3 is fixed in the silicon carbide crystal growth furnace 1 by screws 10 passing through the waist-shaped holes; a hollow column extending upward is fixed on the mounting base 3; the coil assembly includes a supporting foot 5, the supporting foot 5 is provided with a through hole passing through an adjusting screw 4, the bottom of the adjusting screw 4 is threadedly connected to the hollow column, and the top of the adjusting screw 4 is threadedly connected with a locking nut 6. The present invention realizes rapid centering installation of the coil assembly through the centering structure. Through the waist-shaped hole, it is convenient to adjust the angular position of the coil assembly in the circumferential direction. Through the optimization of the connection structure of the coil assembly and the mounting base 3, it is convenient to adjust the height of the heater. The height is adjusted to align with the electrode mounting hole on the side of the furnace body, and the horizontal position of the heater can also be adjusted to the required accuracy. The outer wall of the adjusting screw 4 is provided with a limit protrusion that abuts against the bottom of the supporting foot. The limit protrusion and the locking nut clamp the supporting foot. The hollow column abuts against the nut, and the nut is threadedly connected to the adjusting screw. It is convenient for position locking.

[0050] The coil assembly also includes at least three circumferentially arranged ceramic columns 7, each of which is detachably connected to a support foot 5 at the bottom; a coil positioning and mounting hole is provided on the ceramic column 7; the coil assembly includes a coil 8, on which a copper stud is fixed, and after the copper stud passes through the coil positioning and mounting hole, it is locked and fixed by a copper nut 9. The turn spacing of the coil is ensured so that the heat it emits is uniform.

[0051] See also Figure 3, the coil assembly also includes a copper electrode 11 arranged on the outside of the silicon carbide crystal growth furnace 1; the copper electrode 11 is detachably connected to the coil. It is convenient for assembly. A connecting flange is welded and fixed at the end of the coil; and a sealing ring is sandwiched between the copper electrode and the connecting flange. The sealing ring is located on the outside of the coil end. It also includes a clamp 12, which clamps and fixes the copper electrode 11 and the connecting flange. It is convenient for the copper electrode 11 and the coil to be detachably arranged. The clamp 12 includes two clamping parts arranged opposite to each other, and the clamping parts are detachably connected by bolts. The inner wall of the clamping part is provided with a slot with a cross-section of a trapezoid with a wide inside and a narrow outside; the outer structure of the copper electrode 11 and the connecting flange after splicing matches the slot. A water-cooled flange 15 is installed on the side wall of the silicon carbide crystal growth furnace 1, and the copper electrode 11 extends out of the silicon carbide crystal growth furnace 1 from the water-cooled flange 15; a sealing structure is provided between the copper electrode 11 and the water-cooled flange 15. The sealing structure includes an insulating sleeve 14, a sealing flange 17, a flange sealing ring 16 and an electrode sealing ring 18; the sealing flange 17 is detachably connected to the water-cooling flange 15, and a flange sealing ring 16 is installed between the sealing flange 17 and the water-cooling flange 15; the sealing flange 17 is sleeved on the periphery of the copper electrode 11, and an electrode sealing ring 18 is installed between the sealing flange 17 and the copper electrode 11; the insulating sleeve 14 is fixed on the copper electrode 11, and the inner side of the sealing flange 17 is against the outer side of the insulating sleeve 14; the insulating sleeve 14 is inserted into the mounting hole on the water-cooling flange 15. The sealing flange 17 is Teflon. Two mounting holes for inserting the insulating sleeve 14 are provided on the water-cooling flange 15, and the two mounting holes are used for the extension of the copper electrode 11 connected at both ends of the coil. The insulating sleeve is ceramic.

[0052] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A novel induction heating structure, comprising a heater body, wherein the heater body comprises a coil assembly and a mounting base supporting the coil assembly, characterized in that: The mounting base is mounted in the silicon carbide crystal growth furnace through a centering structure; The centering structure includes an outwardly protruding positioning step arranged on the lower side of the mounting base and an inwardly concave step hole opened at the center of the silicon carbide crystal growth furnace, wherein the step hole is used to embed the positioning step; The mounting base is provided with waist-shaped holes arranged circumferentially, and the mounting base is fixed in the silicon carbide crystal growth furnace by screws passing through the waist-shaped holes; A hollow column extending upward is fixed on the mounting base; The coil assembly comprises a supporting foot, the supporting foot is provided with a through hole for passing an adjusting screw, the bottom of the adjusting screw is threadedly connected to the hollow column, and the top of the adjusting screw is threadedly connected to a locking nut; The coil assembly further comprises at least three circumferentially arranged ceramic columns, and the bottom of each ceramic column is detachably connected to the supporting foot; The ceramic column is provided with a coil positioning and mounting hole; The coil assembly comprises a coil, a copper stud is fixed on the coil, and the copper stud passes through the coil positioning installation hole and is locked and fixed by a copper nut; The coil assembly also includes a copper electrode arranged outside the silicon carbide crystal growth furnace; The copper electrode is detachably connected to the coil; A connecting flange is welded and fixed at the end of the coil; A sealing ring is provided between the copper electrode and the connecting flange; The coil assembly also includes a clamp, which clamps and fixes the copper electrode and the connecting flange; A water-cooling flange is installed on the side wall of the silicon carbide crystal growth furnace, and the copper electrode extends out of the silicon carbide crystal growth furnace from the water-cooling flange; A sealing structure is provided between the copper electrode and the water-cooling flange; The sealing structure comprises an insulating sleeve, a sealing flange, a flange sealing ring and an electrode sealing ring; The sealing flange is detachably connected to the water-cooling flange, and the flange sealing ring is installed between the sealing flange and the water-cooling flange; The sealing flange is sleeved on the periphery of the copper electrode, and the electrode sealing ring is installed between the sealing flange and the copper electrode; The insulating sleeve is fixed on the copper electrode, and the inner side of the sealing flange abuts against the outer side of the insulating sleeve; The insulating sleeve is inserted into the mounting hole on the water-cooling flange.

2. A novel induction heating structure according to claim 1, characterized in that: The clamp comprises two clamping parts arranged opposite to each other, and the clamping parts are detachably connected by bolts.

3. A novel induction heating structure according to claim 2, characterized in that: The inner wall of the clamping piece is provided with a clamping groove with a trapezoidal cross section that is wide inside and narrow outside; The outer structure after the copper electrode and the connecting flange are assembled matches the slot.

4. A novel induction heating structure according to claim 1, characterized in that: The sealing flange is made of Teflon.

5. A novel induction heating structure according to claim 1, characterized in that: The water-cooling flange is provided with two mounting holes for inserting insulating sleeves, and the two mounting holes are used for extending the copper electrodes connected to the two ends of the coil.

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