SiC-CVD rotating shaft

Abstract

The invention relates to the field of rotating shafts, in particular to a SiC-CVD rotating shaft which comprises a rotating middle shaft, an exhaust guide cylinder, a graphite protective sleeve, a rotating shaft supporting ring, a graphite gas supply pipeline, a graphite gas uniformizing disc, a graphite supporting ring, a middle shaft exhaust outer pipe, a base element and a tray. The outer side of the rotating middle shaft is sleeved with a graphite protective sleeve; a rotating shaft supporting ring is mounted at the upper end of the rotating middle shaft; according to the rotating shaft of the SiC-CVD equipment, inert protective gas is introduced into a gap among the rotating middle shaft, the rotating shaft supporting ring and the graphite protective sleeve, so that positive pressure is always kept in the gap in the running process of the equipment, air cooling of the rotating middle shaft can be realized by utilizing the introduced inert gas, and the rotating shaft can be cooled by utilizing the graphite protective sleeve; the air-cooling and anti-corrosion rotating shaft structure has the advantages that the air-cooling and anti-corrosion rotating shaft structure is simple in structure, reaction gas in a furnace chamber can be prevented from entering and contacting with the rotating center shaft made of metal materials through the gaps, corrosion is prevented, maintenance-free operation of the rotating center shaft can be achieved after the air-cooling and anti-corrosion rotating shaft structure is used, and production efficiency and safety of equipment are improved.

Description

Technical Field

[0001] The invention relates to the field of rotating shafts, and in particular to a SiC-CVD rotating shaft. Background Art

[0002] At present, SiC-CVD rotating shafts are mainly made of SUS 316L material. However, in a high temperature environment, the salt acid gas will cause serious corrosion to metal parts as the temperature rises. The corrosion rate of SUS 316L at 480°C is relatively low, less than 0.254 mm per year; but when the temperature rises to 595°C, its corrosion rate will increase sharply, exceeding 1.27 mm per year.

[0003] Currently, in the SiC-CVD process, trichloromethylsilane (CH3SiCl3, abbreviated as MTS) and hydrogen are used as precursor systems and are widely used because of their easy operation and control. MTS, as a reaction gas in the SiC-CVD process, has a large thermal decomposition temperature range. MTS will undergo thermal decomposition in the range of 900 to 1600°C to produce hydrochloric acid.

[0004] Therefore, in view of the problem that in the above process, the hydrochloric acid gas decomposed by the reaction gas at high temperature can easily destroy the purification membrane on the surface of the 316L stainless steel shaft, which will cause serious corrosion of the 316L stainless steel shaft, and then cause the stainless steel shaft to fail and affect the normal operation of the stainless steel shaft, a SiC-CVD rotating shaft can be designed. Summary of the invention

[0005] In order to overcome the problem of corrosion of the stainless steel central axis by hydrochloric acid gas decomposed from the reaction gas at high temperature of the rotating device.

[0006] The technical solution of the present invention is: a SiC-CVD rotating shaft, including a rotating central shaft, an exhaust guide cylinder, a graphite protective sleeve, a rotating shaft support ring, a graphite gas supply pipeline, a graphite gas uniforming disk, a graphite support ring, a central shaft exhaust outer tube, a base element and a tray; a graphite protective sleeve is sleeved on the outer side of the rotating central shaft; a rotating shaft support ring is installed on the upper end of the rotating central shaft; an exhaust guide sleeve is sleeved on the outer side of the graphite protective sleeve; a central shaft exhaust outer tube is arranged on the outer side of the exhaust guide cylinder; a graphite gas supply pipeline is horizontally penetrated between the central shaft exhaust outer tube and the exhaust guide cylinder at the lower end; a graphite gas uniforming disk is installed on the upper end of the graphite gas supply pipeline; the graphite gas uniforming disk is placed on the upper end of the graphite support ring; the upper end of the rotating central shaft is connected to the tray base; and a base element is placed on the upper end of the tray.

[0007] Preferably, Figure 2The dotted arrow in the middle shows the flow path of the protective gas, which is supplied to the gap formed between the gas-distributing plate 6, the graphite support ring 7 and the exhaust guide cylinder 2 through the graphite gas supply pipe 5 to form a certain positive pressure, and then the inert gas is evenly dispersed through the gas-distributing plate 6 to enter the annular gap formed by the rotating central axis 1 and the graphite protective sleeve 3. By continuously introducing the inert gas into the annular gap, the reaction gas is prevented from entering the annular gap through the gap between the graphite protective sleeve 3 and the rotating shaft support ring 4 due to gas diffusion and contacting the metal rotating central axis 1.

[0008] Figure 2 The middle arrow shows the flow path of the protective gas. In order to better prevent the hydrochloric acid gas from entering the gap between the rotating central shaft 1, the rotating shaft support ring 4 and the graphite protective sleeve 3, the gas distribution plate 6 is placed on the graphite support ring 7 and has at least one circle of exhaust holes 12, such as Figure 4 As shown;

[0009] In the present device, at least one circle of exhaust holes 12 is provided on the surface of the gas-distributing disk 6, each circle includes a plurality of exhaust holes, and the shape of the exhaust holes can be any shape such as circular, arc-shaped, rectangular, etc., which is not specifically limited here. When the exhaust holes 12 are circular holes, the diameter of the vent holes can be but not limited to 0.1 mm to 5 mm. After passing through the gas-distributing disk 6, the gas can be evenly blown out before entering the annular gap to obtain a better purge effect, such as Figure 3 shown.

[0010] Preferably, the gap between the rotating shaft support ring and the graphite protection sleeve is directly connected to the furnace chamber.

[0011] Preferably, the graphite gas-distributing disk has at least one circle of exhaust holes; the exhaust holes are distributed in an annular shape with equal spacing; the diameter of the exhaust holes is not limited, but is preferably 0.1 mm to 5 mm.

[0012] Preferably, one end of the graphite gas supply pipeline is connected to the gas supply source; the other end of the graphite gas supply pipeline extends to the inner wall of the graphite protective sleeve.

[0013] Preferably, the upper end of the graphite gas supply pipeline is connected to the gap between the graphite gas uniforming plate, the graphite support ring, and the exhaust guide cylinder.

[0014] Preferably, an annular gap is provided between the rotating central shaft and the graphite protective sleeve.

[0015] Preferably, the gap between the exhaust guide tube and the graphite protective sleeve is connected to the tail gas exhaust pipe.

[0016] Beneficial effects of the present invention:

[0017] The present invention is a rotating shaft device used in a SiC-CVD furnace. By using an inert gas to purge the surface of the rotating shaft, the problem of corrosion and damage of the metal rotating shaft by hydrochloric acid gas in a high temperature environment can be effectively avoided.

[0018] This patent invents a rotating shaft of SiC-CVD equipment. By introducing inert protective gas into the gap between the rotating central shaft, the rotating shaft support ring and the graphite protective sleeve, it is ensured that the above gap is always under positive pressure during the operation of the equipment. The introduced inert gas can be used to achieve air cooling of the rotating central shaft, and the reaction gas in the furnace chamber can be prevented from entering the rotating central shaft in contact with the metal material through the above gap, thereby playing a role in preventing corrosion. Compared with the existing equipment, after a single processing of 2 weeks and 24 hours of operation per day, the surface of the rotating central shaft is severely corroded and damaged and cannot be used any longer. After using this air-cooled, corrosion-resistant rotating shaft structure, the maintenance-free operation of the rotating central shaft can be achieved, which greatly reduces the overall failure rate of the equipment and improves the production efficiency and safety of the equipment:

[0019] (1) Air cooling structure

[0020] In the SiC-CVD rotating center axis structure designed in this patent, a graphite gas supply pipeline is passed through the center axis exhaust outer pipe, and a suitable flow of low-temperature inert gas, such as argon, is introduced to flow through the surface of the rotating center axis to take away heat and reduce the temperature.

[0021] (2) Anti-corrosion methods

[0022] The rotating central axis designed by this patent can be applied to equipment with corrosive reaction gases. The inert gas introduced into the gap between the gas-distributing disk, the rotating central axis and the graphite protective sleeve is evenly dispersed through the gas-distributing disk, and a positive pressure is formed in the gap between the rotating central axis and the rotating graphite protective sleeve, thereby preventing the corrosive gas in the reactor chamber of the equipment from entering and contacting the surface of the rotating central axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The diagram shows a cross-sectional structure diagram of a central shaft support of a conventional device for a rotating shaft of the present invention;

[0024] Figure 2 Shown is a schematic diagram of the flow path of the protective gas of the rotating shaft of the present invention;

[0025] Figure 3 Shown is a partial enlarged schematic diagram of the rotating shaft of the present invention;

[0026] Figure 4 Shown is a schematic diagram of the distribution of exhaust holes on the surface of the gas-distributing disk of the pressing assembly of the rotating shaft of the present invention;

[0027] Figure 5 Shown is a schematic diagram of the interior of a furnace chamber of a rotating shaft according to the present invention.

[0028] Explanation of the accompanying drawings: 1. rotating central axis; 2. exhaust guide cylinder; 3. graphite protective sleeve; 4. rotating shaft support ring; 5. graphite gas supply pipe; 6. graphite gas uniforming disk; 7. graphite support ring; 8. central axis exhaust outer pipe; 9. tail gas exhaust pipe; 10. base element; 11. tray; 12. exhaust hole; 13. furnace chamber. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] See also Figure 1-5 The present invention provides an embodiment: a SiC-CVD rotating axis, comprising a rotating central axis 1; characterized in that: it also comprises an exhaust guide cylinder 2, a graphite protective sleeve 3, a rotating axis support ring 4, a graphite gas supply pipeline 5, a graphite gas uniforming disk 6, a graphite support ring 7, a central axis exhaust outer pipe 8, a base element 10 and a tray 11; the outer side of the rotating central axis 1 is sleeved with a graphite protective sleeve 3; the upper end of the rotating central axis 1 is equipped with a rotating axis support ring 4; the outer side of the graphite protective sleeve 3 is sleeved with an exhaust guide cylinder 2; the outer side of the central axis exhaust outer pipe 8 is arranged on the outer side of the exhaust guide cylinder 2; a graphite gas supply pipeline 5 is horizontally penetrated between the central axis exhaust outer pipe 8 and the exhaust guide cylinder 2 at the lower end; a graphite gas uniforming disk 6 is installed at the upper end of the graphite gas supply pipeline 5; the graphite gas uniforming disk 6 is placed on the upper end of the graphite support ring 7; the upper end of the rotating central axis 1 is connected to the base of the tray 11; the base element 10 is placed on the upper end of the tray 11.

[0031] See also Figure 3 In this embodiment, the gap between the rotating shaft support ring 4 and the graphite protective sleeve 3 is directly connected to the furnace chamber 13; one end of the graphite gas supply pipe 5 is connected to the gas supply source; the other end of the graphite gas supply pipe 5 extends to the inner wall of the graphite protective sleeve 3; the upper end of the graphite gas supply pipe 5 is connected to the gap between the graphite gas uniforming plate 6, the graphite support ring 7, and the exhaust guide cylinder 2; an annular gap is provided between the rotating central axis 1 and the graphite protective sleeve 3; the gap between the exhaust guide cylinder 2 and the graphite protective sleeve 3 is connected to the exhaust pipe 9.

[0032] See also Figure 4 In this embodiment, the surface of the graphite gas distribution disk 6 is provided with at least one circle of exhaust holes 12; the exhaust holes 12 are distributed in an annular shape with equal spacing; the diameter of the exhaust holes 12 is not limited, preferably 0.1 mm to 5 mm.

[0033] Figure 2 The flow path of the reaction gas is shown in the figure. The graphite gas supply pipe 5 vertically penetrates the central axis exhaust outer pipe 8 and the exhaust guide tube 2, one end of which is connected to a gas supply source, and the other end extends to the inner wall of the graphite protective sleeve 3, and a low-temperature inert gas such as argon is introduced (at 10% of the flow rate of the reaction gas);

[0034] Figure 2The dotted arrow in the middle shows the flow path of the protective gas, which is supplied to the gap formed between the graphite gas-distributing plate 6, the graphite support ring 7 and the exhaust guide cylinder 2 through the graphite gas supply pipe 5 to form a certain positive pressure, and then the inert gas is evenly dispersed through the graphite gas-distributing plate 6 to enter the annular gap formed by the rotating central axis 1 and the graphite protective sleeve 3. By continuously introducing the inert gas into the annular gap, the reaction gas is prevented from entering the annular gap through the gap between the graphite protective sleeve 3 and the rotating shaft support ring 4 due to gas diffusion and contacting the metal rotating central axis 1;

[0035] Figure 2 The arrow in the middle shows the flow path of the protective gas. In order to better prevent the hydrochloric acid gas from entering the gap between the rotating central shaft 1, the rotating shaft support ring 4 and the graphite protective sleeve 3, the graphite gas distribution plate 6 is placed on the graphite support ring 7 and has at least one circle of exhaust holes 12, such as Figure 4 As shown;

[0036] In the present device, at least one circle of exhaust holes 12 is provided on the surface of the gas-distributing disk 6, each circle includes a plurality of exhaust holes, and the shape of the exhaust holes can be any shape such as circular, arc-shaped, rectangular, etc., which is not specifically limited here. When the exhaust holes 12 are circular holes, the diameter of the vent holes can be but not limited to 0.1 mm to 5 mm. After passing through the gas-distributing disk 6, the gas can be evenly blown out before entering the annular gap to obtain a better purge effect, such as Figure 3 shown.

[0037] Through the above steps, by passing the inert protective gas into the gap between the rotating central shaft 1, the rotating shaft support ring 4 and the graphite protective sleeve 3, it is ensured that the above gap is always at a positive pressure during the operation of the equipment. The introduced inert gas can be used to achieve air cooling of the rotating central shaft 1, and the reaction gas in the furnace chamber 13 can be prevented from entering the rotating central shaft 1 that contacts the metal material through the above gap, thereby playing a role in preventing corrosion.

Claims

1. A SiC-CVD rotating axis, comprising a rotating central axis (1); characterized in that: It also includes an exhaust guide cylinder (2), a graphite protective sleeve (3), a rotating shaft support ring (4), a graphite gas supply pipeline (5), a graphite gas distribution disk (6), a graphite support ring (7), a central axis exhaust outer pipe (8), a base element (10) and a tray (11); the outer side of the rotating central axis (1) is covered with a graphite protective sleeve (3); the upper end of the rotating central axis (1) is equipped with a rotating shaft support ring (4); the outer side of the graphite protective sleeve (3) is covered with an exhaust guide cylinder (2); the outer side of the central axis exhaust outer pipe (8) is arranged on the outer side of the exhaust guide cylinder (2); a graphite gas supply pipeline (5) is horizontally penetrated between the central axis exhaust outer pipe (8) and the exhaust guide cylinder (2) at the lower end; a graphite gas distribution disk (6) is installed at the upper end of the graphite gas supply pipeline (5); the graphite gas distribution disk (6) is placed on the upper end of the graphite support ring (7); the upper end of the rotating central axis (1) is connected to the base of the tray (11); and the base element (10) is placed on the upper end of the tray (11).

2. The SiC-CVD rotating shaft according to claim 1, characterized in that: The gap between the rotating shaft support ring (4) and the graphite protection sleeve (3) is directly connected to the furnace chamber (13).

3. The SiC-CVD rotating shaft according to claim 1, characterized in that: The surface of the graphite gas-distributing disk (6) is provided with at least one circle of exhaust holes (12); the exhaust holes (12) are distributed in a circular shape with equal spacing; the diameter of the exhaust holes (12) is not limited, and is preferably 0.1 mm to 5 mm.

4. The SiC-CVD rotating shaft according to claim 1, characterized in that: One end of the graphite gas supply pipeline (5) is connected to the gas supply source; the other end of the graphite gas supply pipeline (5) extends to the inner wall of the graphite protective sleeve (3).

5. The SiC-CVD rotating shaft according to claim 1, characterized in that: The upper end of the graphite gas supply pipeline (5) is connected to the gap between the graphite gas uniforming plate (6), the graphite support ring (7) and the exhaust guide cylinder (2).

6. The SiC-CVD rotating shaft according to claim 1, characterized in that: An annular gap is provided between the rotating central shaft (1) and the graphite protective sleeve (3).

7. The SiC-CVD rotating shaft according to claim 1, characterized in that: The gap between the exhaust guide tube (2) and the graphite protection sleeve (3) is communicated with the tail gas exhaust pipeline (9).

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