Magnetic fluid sealing device and extension equipment

Abstract

The utility model belongs to the technical field of CVD equipment, and discloses a magnetofluid sealing device and epitaxy equipment, the magnetofluid sealing device comprises a cooling body and a magnetofluid assembly, the cooling body is provided with a first inlet and a first outlet, and the first inlet and the first outlet are communicated through a first flow channel arranged in the cooling body; the magnetic fluid assembly comprises a magnetic current cavity and a rotating shaft; the first end of the cooling body penetrates through the magnetic flow cavity, so that the first inlet and the first outlet are located outside the magnetic flow cavity, a magnetic flow cavity capable of containing the magnetic fluid is formed between the cooling body and the magnetic flow cavity, the rotating shaft is connected to the cooling body, and the second end of the cooling body can be connected with the driving part to drive the cooling body and the rotating shaft to rotate; the epitaxy equipment adopts the magnetofluid sealing device to perform heat exchange on the rotating shaft and the magnetofluid in the magnetic flow cavity, so that the temperature of the rotating shaft and the magnetofluid is reduced, and normal operation of the rotating shaft and the magnetofluid is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to CVD equipment technical field especially relates to a magnetic fluid sealing device and epitaxial equipment. BACKGROUND

[0002] Chemical vapor deposition (CVD) can be divided into horizontal type and vertical type, and the uniformity of the epitaxial thickness and the doping concentration of the epitaxial wafer is a key parameter affecting the performance of silicon carbide devices, and the epitaxial wafer of the horizontal type is farther away from the air inlet position, and the thickness is thinner, and the air inlet of the vertical type is located at the center, so the center thickness of the epitaxial wafer is thick, and the periphery is thin.

[0003] In the prior art, the rotation of the base drives the rotation of the epitaxial wafer, which can greatly reduce the thickness and the non-uniformity of the doping concentration. However, since the rotating shaft needs to pass through the cavity and be connected with the motor, and the cavity needs to be sealed and maintain a certain degree of vacuum, the magnetic fluid sealing device is usually used to dynamically seal the rotating shaft in the prior art. In the process engineering, the temperature in the cavity can reach 1700 DEG C at the highest, at which time the temperature conducted on the rotating shaft will also be very high, and the working temperature of the ordinary magnetic fluid sealing device is limited to about 80 DEG C-120 DEG C, and by using special high-temperature carrier liquid and magnetic material, a temperature as high as 300 DEG C can be tolerated. However, at a higher temperature (such as more than 400 DEG C), its performance will be severely affected, so the magnetic fluid sealing device needs to be cooled when used. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a kind of magnetic fluid sealing device and epitaxial equipment to solve the problem of cooling magnetic fluid sealing device.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] The magnetic fluid sealing device comprises:

[0007] The cooling body is provided with a first inlet and a first outlet, and the first inlet and the first outlet are communicated by a first flow channel arranged in the cooling body;

[0008] The magnetic fluid assembly comprises a magnetic flow cavity and a rotating shaft; the first end of the cooling body penetrates the magnetic flow cavity, and the first inlet and the first outlet are located outside the magnetic flow cavity; a magnetic flow cavity capable of containing magnetic fluid is formed between the cooling body and the magnetic flow cavity, the rotating shaft is connected to the cooling body, and the second end of the cooling body can be connected to a driving member to drive the cooling body and the rotating shaft to rotate.

[0009] In some embodiments, the magnetic fluid sealing device further comprises a support seat capable of being sealingly connected to the magnetic flow cavity and the external cavity, the support seat having a through cavity through which the rotating shaft passes, the support seat being provided with a second inlet and a second outlet, the second inlet and the second outlet being in communication through a second flow channel provided in the support seat.

[0010] In some embodiments, the inner cavity wall of the through cavity is provided with a third groove at the second flow channel.

[0011] In some embodiments, the third groove is circumferentially arranged along the inner cavity wall of the through cavity.

[0012] In some embodiments, a plurality of the third grooves are distributed along the axial direction of the through cavity.

[0013] In some embodiments, the end surface of the support seat facing the magnetic flow cavity is provided with a seal around the through cavity.

[0014] In some embodiments, the end surface of the support seat facing the magnetic flow cavity is provided with a groove around the through cavity, and the seal is embedded in the groove.

[0015] In some embodiments, the second end of the cooling body is further provided with a synchronous wheel connected to the driving member.

[0016] In some embodiments, the magnetic fluid sealing device further comprises a slip ring having a liquid inlet flow channel and a liquid outlet flow channel, the liquid inlet flow channel being in communication with the first inlet, and the liquid outlet flow channel being in communication with the first outlet.

[0017] Also provided is an epitaxial device comprising a reaction cavity and the magnetic fluid sealing device as described above, the rotating shaft being capable of penetrating into the reaction cavity away from the one end of the cooling body to connect a susceptor for fixing a substrate in the reaction cavity.

[0018] The utility model discloses the beneficial effects of:

[0019] The cooling fluid flows through the first flow channel, so that the cooling body can directly exchange heat with the rotating shaft on one hand, and can also directly exchange heat with the magnetic fluid on the other hand, thereby reducing the temperature of the two and ensuring normal operation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is the sectional view of the magnetic fluid sealing device in the utility model;

[0021] Fig. 2 is the connection schematic diagram of the cooling body and the magnetic fluid assembly in the utility model;

[0022] Fig. 3 is a sectional view of the support seat in the utility model.

[0023] In the drawing:

[0024] 10, cooling body; 11, first flow channel; 12, first inlet; 13, first outlet; 14, mounting hole;

[0025] 20, magnetic fluid assembly; 21, magnetic flow cavity; 22, rotating shaft; 23, magnetic flow cavity; 24, bearing;

[0026] 30, support seat; 31, through cavity; 32, second flow channel; 33, third groove; 34, embedding groove;

[0027] 40, synchronous wheel;

[0028] 50, slip ring; 51, liquid inlet flow channel; 52, liquid outlet flow channel;

[0029] 60, reaction cavity;

[0030] 70, base. DETAILED DESCRIPTION

[0031] The utility model will be further explained in detail below in combination with the drawings and examples. It can be understood that the specific examples described here are only used to explain the utility model, and not limited to the utility model. In addition, it should be noted that in order to facilitate the description, only the part related to the utility model is shown in the drawing, not all the structures.

[0032] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0033] In the utility model, unless otherwise explicitly specified and limited, the first feature "on" or "below" the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0034] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0035] As shown in Figs. 1 to 3 The present application provides a magnetic fluid sealing device, which comprises a cooling body 10 and a magnetic fluid assembly 20, the cooling body 10 is provided with a first inlet 12 and a first outlet 13, the first inlet 12 and the first outlet 13 are communicated through a first flow channel 11 arranged in the cooling body 10; the magnetic fluid assembly 20 comprises a magnetic flow cavity 21 and a rotating shaft 22; the first end of the cooling body 10 penetrates the magnetic flow cavity 21, the first inlet 12 and the first outlet 13 are located outside the magnetic flow cavity 21, the magnetic flow cavity 23 capable of containing magnetic fluid is formed between the cooling body 10 and the magnetic flow cavity 21, the rotating shaft 22 is connected to the cooling body 10, and the second end of the cooling body 10 can be connected to a driving member to drive the cooling body 10 and the rotating shaft 22 to rotate.

[0036] Thus, the cooling fluid flows through the first flow channel 11, so that the cooling body 10 can directly exchange heat with the rotating shaft 22 on the one hand, and can also directly exchange heat with the magnetic fluid on the other hand, thereby reducing the temperature of the two and ensuring normal operation.

[0037] It should be noted here that a magnet is arranged in the magnetic flow cavity 23 to stabilize the magnetic fluid contained therein for sealing by the magnetic fluid. This is a prior art for fixing the magnetic fluid when the magnetic fluid is used for sealing, and will not be described in detail.

[0038] As shown in Fig. 2 In some embodiments, in order to stabilize the cooling body 10, a bearing 24 is further arranged in the magnetic flow cavity 21, and the cooling body 10 is rotatably connected to the magnetic flow cavity 21 through the bearing 24 to ensure stable rotation.

[0039] In some embodiments, in order to facilitate installation of the rotating shaft 22, the first end of the cooling body 10 is provided with a mounting hole 14, and the end of the rotating shaft 22 is fixed in the mounting hole 14. In the present embodiment, the mounting hole 14 extends as far as possible from the first end to the second end of the cooling body 10, so that the rotating shaft 22 extends as far as possible into the cooling body 10. Further, the first flow channel 11 is located between the rotating shaft 22 and the magnetic flow cavity 23, thereby improving the heat exchange efficiency.

[0040] In some embodiments, the magnetic fluid sealing device further comprises a support base 30, which is capable of being sealingly connected to the magnetic flow cavity 21 and the external cavity, and has a through cavity 31 through which the rotating shaft 22 passes, and is provided with a second inlet and a second outlet, which are in communication through a second flow channel 32 arranged in the support base 30, so that the cooling fluid flows through the first flow channel 11 and the second flow channel 32 to exchange heat with the magnetic fluid in the rotating shaft 22 and the magnetic flow cavity 21, thereby improving the heat exchange efficiency.

[0041] Based on the following formula:

[0042] Formula one: Q 总 = Q1+Q2; Formula two: Q1= C0×∈ 12 ×F1[(T1 / 100) 4 -(T2 / 100) 4 ]; Formula three: ∈ 12 =1 / (1 / ∈1+F1 / F2(1 / ∈1-1)); Formula four: Q2=h×A(T S -T f );

[0043] Wherein, Q 总 is the total heat; Q1 is the radiation heat exchange heat; Q2 is the convection heat exchange heat; C O is the radiation coefficient of a black body; F1 is the surface area of the internal object; F2 is the surface area of the external object; h is the convection heat exchange coefficient; T1 is the surface temperature of the high-temperature object; T2 is the surface temperature of the low-temperature object; ∈1 is the black body radiation coefficient of the internal object; ∈2 is the black body radiation coefficient of the external object; T S : surface temperature of the object; T f fluid temperature;

[0044] As Fig. 3 shown, in some embodiments, the inner cavity wall of the through cavity 31 is provided with a third groove 33 at the second flow channel 32, which increases the surface area of the through cavity 31, thereby increasing F2 and Q1, i.e., the heat exchanged by the rotating shaft 22 to the second flow channel 32 through radiation heat exchange is increased, thereby improving the heat exchange efficiency. Specifically, the third groove 33 is circumferentially arranged along the inner cavity wall of the through cavity 31, so that the third groove 33 surrounds the rotating shaft 22, thereby ensuring the heat exchange efficiency. Further, the third groove 33 is provided with a plurality of third grooves 33, which are distributed along the axial direction of the through cavity 31, thereby improving the heat exchange efficiency. It should be noted that the second flow channel 32 in the support base 30 not only exchanges heat with the rotating shaft 22, but also reduces the ambient temperature of the periphery of the support base 30.

[0045] The end face of the support base 30 facing the magnetic flow cavity 21 is provided with an embedding groove 34 surrounding the through cavity 31, and a sealing element is arranged in the embedding groove 34, so that the sealing element is squeezed by the support base 30 and the magnetic flow cavity 21 together, thereby ensuring the sealing between the support base 30 and the magnetic flow cavity 21. The magnetic flow cavity 21 and the support base 30 can be provided with connecting holes for connection, which can be but are not limited to counter-sunk holes or screw holes and the like.

[0046] In some embodiments, in order to drive the rotation of the rotating shaft 22, the second end of the cooling body 10 is further provided with a synchronous wheel 40, so that an external driving member can drive the cooling body 10 to rotate the rotating shaft 22 through the synchronous wheel 40. It can be understood that, since the synchronous wheel 40 drives the rotating shaft 22 to rotate, in order to facilitate the inflow and outflow of cooling fluid, the magnetic fluid sealing device further comprises a slip ring 50, which has an inflow channel 51 and an outflow channel 52, and the inflow channel 51 and the outflow channel 52 are connected with the first inlet 12 and the first outlet 13 respectively, so that the cooling fluid is injected through the slip ring 50. The slip ring 50 is a prior structure and will not be described in detail.

[0047] The application also provides an epitaxial equipment, which comprises a reaction cavity 60 and the above-mentioned magnetic flow sealing device. The end of the support base 30 away from the magnetic fluid assembly 20 is sealingly fixed on the reaction cavity 60, and the end of the rotating shaft 22 away from the cooling body 10 penetrates into the reaction cavity 60, and is connected with a base 70 for fixing a substrate in the reaction cavity 60, so that the rotating shaft 22 can be heat-exchanged through the first flow channel 11 on the magnetic flow cavity 21 and the second flow channel 32 in the support base 30, thereby reducing the temperature of the rotating shaft 22 and the magnetic fluid assembly 20 and ensuring the normal operation thereof. Exemplarily, the support base 30 and the reaction cavity 60 can also be sealed by a sealing element, and details will not be described herein.

[0048] Obviously, the above embodiments of the application are merely exemplary and are not intended to limit the embodiments of the application. Those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the protection scope of the application. It is unnecessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement made within the spirit and principle of the application shall be included in the protection scope of the claims of the application.

Claims

1. A magnetic fluid seal apparatus, characterized by, The application relates to a magnetic fluid sealing device. The magnetic fluid sealing device comprises a cooling body (10) provided with a first inlet (12) and a first outlet (13) which are communicated through a first flow channel (11) arranged in the cooling body (10); a magnetic fluid assembly (20) comprising a magnetic fluid cavity (21) and a rotating shaft (22); the first end of the cooling body (10) penetrates the magnetic fluid cavity (21), and the first inlet (12) and the first outlet (13) are located outside the magnetic fluid cavity (21); a magnetic fluid cavity (23) capable of containing magnetic fluid is formed between the cooling body (10) and the magnetic fluid cavity (21), and the rotating shaft (22) is connected to the cooling body (10), and the second end of the cooling body (10) can be connected to a driving member to drive the cooling body (10) and the rotating shaft (22) to rotate. The magnetic fluid sealing device further comprises a support seat (30) which can be sealingly connected to the magnetic fluid cavity (21) and an external cavity, and the support seat (30) has a through cavity (31) through which the rotating shaft (22) penetrates, and the support seat (30) is provided with a second inlet and a second outlet which are communicated through a second flow channel (32) arranged in the support seat (30).

2. The magnetic fluid seal of claim 1, wherein, The inner cavity wall of the through cavity (31) is provided with a third groove (33) corresponding to the second flow channel (32).

3. The magnetic fluid seal of claim 2, wherein, The third groove (33) is circumferentially arranged along the inner cavity wall of the through cavity (31).

4. The magnetic fluid seal of claim 3, wherein, A plurality of third grooves (33) are distributed along the axial direction of the through cavity (31).

5. The magnetic fluid seal of claim 4, wherein, The end surface of the support seat (30) facing the magnetic fluid cavity (21) is provided with a sealing member surrounding the through cavity (31).

6. The magnetic fluid seal of claim 2, wherein, The end surface of the support seat (30) facing the magnetic fluid cavity (21) is provided with a groove (34) surrounding the through cavity (31), and the sealing member is embedded in the groove (34).

7. The magnetic fluid seal of claim 6 wherein, The second end of the cooling body (10) is further provided with a synchronous wheel (40) connected to the driving member.

8. The magnetic fluid seal of claim 1, wherein, The magnetic fluid sealing device further comprises a slip ring (50) having a liquid inlet flow channel (51) and a liquid outlet flow channel (52), wherein the liquid inlet flow channel (51) communicates with the first inlet (12), and the liquid outlet flow channel (52) communicates with the first outlet (13).

9. The magnetic fluid seal of claim 3 wherein, The magnetic fluid sealing device according to any one of claims 1-9, wherein one end of the rotating shaft (22) away from the cooling body (10) can penetrate into a reaction cavity (60) to be connected to a pedestal (70) for fixing a substrate in the reaction cavity (60).

10. Epitaxial apparatus comprising a reaction chamber (60), characterized in that ​

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