Ultra-pure composite stainless steel pipe for semiconductor

Abstract

The utility model discloses a kind of ultra-high purity composite structure stainless steel pipes for semiconductor, it is related to semiconductor material conveying technical field, including outer layer base pipe and inner layer cladding pipe arranged in outer layer base pipe, vacuum insulation layer is arranged between outer layer base pipe and inner layer cladding pipe, and the outside of outer layer base pipe is provided with protective layer, and the outside of outer layer base pipe is provided with suction hole. The ultra-high purity composite structure stainless steel pipe for semiconductor, the performance and economy are considered, only in the inner layer using expensive VIM+VAR grade material with medium contact, thickness is thinner;Outer layer uses ordinary 316L material pressure, substantially reduces raw material cost, and the cost performance is extremely high;Double protection ultra-high purity: vacuum insulation layer effectively prevents the impurities in outer layer base pipe from migrating to inner layer flow passage by grain boundary diffusion and other ways, can also isolate the pollution of external environment to inner layer flow passage, and reliability is far more than single material pipe.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor material delivery technology, specifically to an ultra-high purity composite stainless steel tube for semiconductors. Background Technology

[0002] Stainless steel pipes used in semiconductor manufacturing to transport ultrapure water, high-purity specialty gases, and high-purity chemicals require extremely smooth inner surfaces (low roughness Ra value) and extremely low metal ion precipitation rates. Currently, 316LEP (electrochemically polished) steel pipes made of a single material are commonly used.

[0003] Patent CN218378167U discloses a high-strength stainless steel pipe that is resistant to pressure and deformation. The first and second clamping blocks make the connection between the stainless steel pipes more secure and improve the stability of the connection. Furthermore, the carbon steel layer enhances the pressure resistance and deformation resistance of the first and second steel pipe bodies, thereby increasing the service life of the stainless steel pipe.

[0004] While the stainless steel pipe in the aforementioned patent solves the pressure resistance problem, the following issues still exist: In order to minimize precipitation, the aforementioned patented technology requires the use of extremely expensive 316LVV (such as 316LVIM+VAR) material to make the pipe. The use of 316LVV material to make the pipe will increase the cost, so its economic efficiency is poor. If ordinary 316L is used as the matrix and only the inner wall is treated, the risk of precipitation of the main body material still exists.

[0005] To address the aforementioned issues, innovative designs are urgently needed based on the existing stainless steel pipe structure. Utility Model Content

[0006] The purpose of this invention is to provide an ultra-high purity composite stainless steel tube for semiconductors, in order to solve the problems mentioned in the background art, such as the high cost of manufacturing the entire tube with a single high-purity material and the possibility of impurities in ordinary matrix materials migrating and precipitating into the medium inside the tube.

[0007] To achieve the above objectives, this utility model provides the following technical solution: an ultra-high purity composite stainless steel tube for semiconductors, comprising an outer base tube and an inner coating tube disposed inside the outer base tube, wherein a vacuum isolation layer is disposed between the outer base tube and the inner coating tube, and a protective layer is disposed on the outer side of the outer base tube, and an air extraction hole is provided on the outer side of the outer base tube, and the inner coating tube and the outer base tube are sealed and welded at both ends by vacuum electron beam welding to form the vacuum isolation layer.

[0008] Preferably, the outer base tube is a common 316L stainless steel tube with an outer diameter of 60.5 mm and a wall thickness of 2.5 mm, and the outer base tube and the inner covering tube are coaxially arranged, the main function of which is to provide structural strength and rigidity.

[0009] Preferably, the inner cladding tube is a 316LVIM+VAR stainless steel tube with an outer diameter of 54mm and a wall thickness of 1.5mm. Both the inner and outer surfaces of the inner cladding tube have a mirror-like structure. The inner cladding tube is a thin-walled 316LVIM+VAR stainless steel tube with ultra-low carbon and low impurity content. Its inner surface is electrochemically polished to achieve a mirror effect with a surface roughness Ra≤0.1µm, forming an ultra-high cleanliness flow channel in contact with the medium.

[0010] Preferably, the vacuum isolation layer is a vacuum ring structure with an outer diameter of 58 mm and a thickness of 4 mm, and the vacuum isolation layer is connected to the air extraction hole. The vacuum isolation layer is a vacuum cavity located between the outer base tube and the inner coating tube, and its function is to block the path of ions and other impurities that may be precipitated in the outer base tube to migrate to the inner layer.

[0011] Preferably, the protective layer is made of polyurethane and has a thickness of 0.1 mm. The polyurethane material is used to isolate the influence of electrons in the air on the performance of the pipeline.

[0012] Preferably, an arc-shaped rubber ring is bonded to the outer side of the outer base tube, and an arc-shaped magnetic plate is bonded to the outer side of the arc-shaped rubber ring. The arc-shaped rubber ring is used to isolate the contact between the tube and the arc-shaped magnetic plate.

[0013] Preferably, the arc-shaped rubber ring and the arc-shaped magnetic plate are equidistantly arranged on the outer side of the outer base tube, and the arc-shaped rubber ring and the arc-shaped magnetic plate have a ring-shaped structure when viewed from the side.

[0014] Compared with the prior art, the beneficial effects of this utility model are: 1. This ultra-high purity composite stainless steel pipe combines ultimate performance with economy. Not only does it use expensive VIM+VAR grade material in the inner layer that comes into contact with the medium, resulting in a thinner thickness, but it also uses ordinary 316L material in the outer layer to withstand pressure, which greatly reduces the cost of raw materials and makes it extremely cost-effective.

[0015] 2. This ultra-high purity composite stainless steel pipe provides double protection for ultra-high purity. The vacuum isolation layer effectively prevents impurities (such as sulfur and phosphorus inclusions) in the outer base pipe from migrating to the inner flow channel through grain boundary diffusion, while also isolating the inner flow channel from external environmental contamination. Its reliability far exceeds that of single-material pipes.

[0016] 3. The ultra-high purity composite stainless steel pipe has reliable connections and consistent performance. The unique end processing and welding technology ensures that the material purity and inner wall quality at the connection joints are completely consistent with the inner layer of the pipe, with no weak points.

[0017] 4. This ultra-high purity composite stainless steel pipe has additional thermal insulation properties. The vacuum insulation layer structure effectively reduces the heat exchange between the ambient temperature and the medium inside the pipe, which is conducive to maintaining the stability of the process medium temperature.

[0018] 5. This ultra-high purity composite stainless steel pipe has a long service life and low maintenance cost. The high-purity material of the inner layer itself has better corrosion resistance. Combined with vacuum protection, it extends the service life of the pipeline system under harsh working conditions and reduces the maintenance cost throughout the entire life cycle.

[0019] 6. This ultra-high purity composite stainless steel conveyor has a fast conveying speed. The outer arc-shaped magnetic plate can change the magnetic field inside the pipe. When conveying materials with electronic properties, the change in the strength of the magnetic field can increase the material's movement speed and shorten the material conveying time. Attached Figure Description

[0020] Figure 1 This is a top view of the structure of this utility model; Figure 2 This is a three-dimensional structural diagram of the present invention; Figure 3 This is a three-dimensional structural diagram of the present invention in an exploded state; Figure 4 This is a top view of the outer base tube structure of this utility model; Figure 5 This is a schematic diagram of the left-side structure of this utility model; Figure 6 This is a three-dimensional structural diagram of the outer base tube of this utility model, viewed from below.

[0021] In the diagram: 1. Outer base tube; 2. Vacuum insulation layer; 3. Inner coating tube; 4. Protective layer; 5. Arc-shaped rubber ring; 6. Arc-shaped magnetic plate; 7. Air extraction hole. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] In a specific embodiment, this utility model provides the following technical solution: an ultra-high purity composite structure stainless steel tube for semiconductors, such as... Figures 1-6 As shown; The outer base tube 1 and the inner covering tube 3 are arranged inside the outer base tube 1. A vacuum isolation layer 2 is provided between the outer base tube 1 and the inner covering tube 3. A protective layer 4 is provided on the outside of the outer base tube 1, and an air extraction hole 7 is opened on the outside of the outer base tube 1. The outer base tube 1 is a common 316L stainless steel tube with an outer diameter of 60.5mm and a wall thickness of 2.5mm. The outer base tube 1 and the inner covering tube 3 are arranged coaxially. The inner covering tube 3 is a 316LVIM+VAR stainless steel tube with an outer diameter of 54mm and a wall thickness of 1.5mm. Furthermore, both the inner and outer surfaces of the inner layer tube 3 are mirror-like structures. The vacuum isolation layer 2 is a vacuum ring structure with an outer diameter of 58 mm and a thickness of 4 mm. The vacuum isolation layer 2 is connected to the air extraction hole 7. The protective layer 4 is made of polyurethane and has a thickness of 0.1 mm. The function of the vacuum isolation layer 2 is to block the migration path of ions and other impurities that may be precipitated in the outer base tube to the inner layer. The inner surface of the inner layer tube 3 is electrochemically polished to achieve a mirror effect with a surface roughness Ra≤0.1µm, forming an ultra-high cleanliness flow channel in contact with the medium.

[0024] When using this semiconductor-grade ultra-high purity composite stainless steel tube, pretreatment of the outer base tube 1 and the inner coating tube 3 is required. During the pretreatment process, a standard 316L stainless steel tube with an outer diameter of 60.5mm and a wall thickness of 2.5mm is selected as the outer base tube 1, and polyurethane material is sprayed onto the outside of the outer base tube 1. Then, a 316LVIM+VAR stainless steel tube with an outer diameter of 54mm and a wall thickness of 1.5mm is selected as the inner coating tube 3, and the inner and outer surfaces of the inner coating tube 3 are initially polished. At this point, the outer base tube 1 and the inner coating tube 3 can be assembled: the inner coating tube 3 is inserted into the outer base tube 1, keeping the two sets of tubes coaxial, and welding positions are reserved at both ends. Then, the ends of the two sets of tubes are sealed and welded. The assembled tubes are then placed in a vacuum. In the electron beam welding machine, the ends of the inner layer cladding tube 3 and the outer layer base tube 1 are fused together by an electron beam at both ends of the tube to form a vacuum electron beam weld. This welding process is completed in a high vacuum environment to ensure that the weld is pure and can be effectively sealed. After the welding is completed, a vacuum needs to be drawn through the evacuation hole 7: the cavity between the inner and outer layers is drawn to a high vacuum of ≤10-3Pa through the evacuation hole 7 pre-drilled on the outer layer base tube 1, and then the evacuation hole 7 is sealed by electron beam welding to finally form a vacuum isolation layer 2. Finally, the inner surface of the inner layer cladding tube 3 can be finally treated: the inner wall of the inner cavity of the formed composite tube, i.e. the inner layer cladding tube 3, is finally electrochemically polished to ensure that its surface roughness Ra value is not greater than 0.1µm. This completes the tube processing process. An arc-shaped rubber ring 5 is bonded to the outside of the outer base tube 1, and an arc-shaped magnetic plate 6 is bonded to the outside of the arc-shaped rubber ring 5. The arc-shaped rubber ring 5 and the arc-shaped magnetic plate 6 are equidistantly arranged on the outside of the outer base tube 1, and the arc-shaped rubber ring 5 and the arc-shaped magnetic plate 6 form a ring structure when viewed from the side. The main function of the outer base tube 1 is to provide structural strength and rigidity.

[0025] Furthermore, an arc-shaped rubber ring 5 is bonded to the outside of the outer base pipe 1 of the pipe, so that the two sets of arc-shaped rubber rings 5 ​​are joined together to form a ring-shaped rubber ring. Then, arc-shaped magnetic plates 6 of different thicknesses can be bonded to the inside of the arc-shaped rubber ring 5. It should be noted that the thickness of the arc-shaped magnetic plate 6 gradually increases in the direction of pipe conveying, in order to enhance the magnetic field inside the pipe, thereby accelerating the conveying speed of materials with electronic properties inside the pipe.

[0026] During pipe end processing, at each end requiring connection, approximately 30mm of the outer base pipe 1 and vacuum insulation layer 2 are cut off using a lathe, causing the inner coating pipe 3 to extend outward by about 25mm, forming a connector made of pure VIM+VAR material. During pre-welding preparation, the exposed inner coating pipe 3 connector is cleaned and degreased. Welding is then performed using an automatic rail welding machine under high-purity argon protection, aligning and welding the connectors of the two pipes together to form an automatic rail weld. Welding parameters must be precisely controlled to ensure full penetration and good back-side formation. Post-weld processing involves necessary localized electrochemical polishing of the welded joint's inner surface to ensure the weld's inner surface roughness matches that of the inner pipe wall, completing the connection. This completes the overall pipe processing, increasing its practicality.

[0027] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-purity composite stainless steel tube for semiconductor applications, characterized in that: It includes an outer base tube (1) and an inner coating tube (3) disposed inside the outer base tube (1). A vacuum isolation layer (2) is disposed between the outer base tube (1) and the inner coating tube (3). A protective layer (4) is disposed on the outside of the outer base tube (1). An air extraction hole (7) is opened on the outside of the outer base tube (1). The outer base tube (1) and the inner coating tube (3) are provided to prevent the precipitation of the transported material.

2. The ultra-high purity composite stainless steel tube for semiconductors according to claim 1, characterized in that: The outer base tube (1) is a ring structure with an outer diameter of 60.5 mm and a wall thickness of 2.5 mm when viewed from above, and the outer base tube (1) and the inner covering tube (3) are coaxially arranged.

3. The ultra-high purity composite stainless steel tube for semiconductors according to claim 1, characterized in that: The inner layer covering tube (3) is a ring structure with an outer diameter of 54 mm and a wall thickness of 1.5 mm when viewed from above, and both the inner and outer surfaces of the inner layer covering tube (3) are mirror-like structures.

4. The ultra-high purity composite stainless steel tube for semiconductors according to claim 1, characterized in that: The vacuum isolation layer (2) is a vacuum ring structure with an outer diameter of 58 mm and a thickness of 4 mm, and the vacuum isolation layer (2) is connected to the air extraction hole (7).

5. The ultra-high purity composite stainless steel tube for semiconductors according to claim 1, characterized in that: The protective layer (4) is made of polyurethane and has a thickness of 0.1 mm.

6. The ultra-high purity composite stainless steel tube for semiconductors according to claim 1, characterized in that: An arc-shaped rubber ring (5) is bonded to the outside of the outer base tube (1), and an arc-shaped magnetic plate (6) is bonded to the outside of the arc-shaped rubber ring (5).

7. The ultra-high purity composite stainless steel tube for semiconductors according to claim 6, characterized in that: The arc-shaped rubber ring (5) and the arc-shaped magnetic plate (6) are equidistantly arranged on the outside of the outer base tube (1), and the arc-shaped rubber ring (5) and the arc-shaped magnetic plate (6) have a ring structure when viewed from the side.

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