JP2023160075A - Bubbler tube and bubbler - Google Patents

Abstract

To provide a bubbler tube that allows a bubbler to be excellent in chemical resistance and heat resistance and have a high degree of freedom in installation.SOLUTION: A bubbler tube includes: a first tube, at least part thereof being a porous structure, including a polytetrafluoroethylene; and a second tube having a non-porous structure and including a fluorine resin. The second tube has one end connected to one end of the first tube.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tube for a bubbler and a bubbler.

BACKGROUND ART In semiconductor manufacturing processes and the like, gas injectors, so-called bubblers, are used to prevent retention of chemical solutions and eliminate temperature unevenness. Bubblers used for these purposes are required to have excellent chemical resistance and heat resistance. Therefore, bubblers made of fluororesin having excellent chemical resistance and heat resistance are on the market.

Many of the known bubblers have a cylindrical, spherical, or flat plate shape that does not have flexibility, so there is a problem that the degree of freedom in installation is low. If the location of the bubbler is assumed at the time of design, the degree of freedom in installation is often not a major problem. However, for example, when relocating a bubbler to a location where it is not expected to be used, or when it is discovered that the agitation efficiency is poor for the first time after use, and a change in the installation location is required, etc., the bubbler may be relocated. In some cases, bubblers having the shapes described above tend to be space constrained.

Japanese Patent Application Publication No. 2000-331980 Japanese Patent Application Publication No. 61-66730

The present invention has been made in view of the above circumstances, and provides a bubbler tube that has excellent chemical resistance and heat resistance and can realize a bubbler with a high degree of freedom in installation, and a bubbler equipped with the bubbler tube. With the goal.

According to a first aspect of the invention, a tube for a bubbler is provided. The bubbler tube includes a first tube that has a porous structure at least in part and contains polytetrafluoroethylene, and a second tube that has a non-porous structure and contains a fluororesin. One end of the second tube is connected to one end of the first tube.

According to a second aspect of the invention, a bubbler is provided. The bubbler includes a bubbler tube according to the first side and a gas supply means. The gas supply means is connected to the other end of the second tube.

According to the present invention, it is possible to provide a bubbler tube that has excellent chemical resistance and heat resistance and can realize a bubbler with a high degree of freedom in installation, and a bubbler equipped with the bubbler tube.

FIG. 1 is a cross-sectional view schematically showing an example of a bubbler tube according to an embodiment. FIG. 3 is a cross-sectional view schematically showing a state in which a bubbler tube according to a reference example is connected to a gas supply means. FIG. 2 is a cross-sectional view schematically showing a state in which a bubbler tube according to an embodiment is connected to a gas supply means. FIG. 3 is a cross-sectional view schematically showing another example of the bubbler tube according to the embodiment. FIG. 3 is a cross-sectional view schematically showing another example of the bubbler tube according to the embodiment. The perspective view which shows roughly an example of the 3rd tube which the tube for bubblers concerning an embodiment may include. FIG. 7 is a cross-sectional view of the third tube shown in FIG. 6 taken along line XII-XII. FIG. 7 is a diagram schematically showing an example of a bubbler according to another embodiment.

Hereinafter, embodiments will be described with reference to the drawings as appropriate. Note that common components throughout the embodiments are denoted by the same reference numerals, and redundant explanations will be omitted. In addition, each figure is a schematic diagram for explaining the embodiment and promoting understanding thereof, and the shape, dimensions, ratio, etc. may differ from the actual device, but these are in accordance with the following explanation and known technology. The design can be changed as appropriate by taking into consideration.

(First embodiment)
A bubbler tube according to an embodiment includes a first tube at least partially having a porous structure. The porous structure of the first tube is due to the properties of polytetrafluoroethylene (PTFE), which does not exhibit thermal fluidity. That is, the porous structure of the first tube is a fine structure consisting of nodes and fibrils made of PTFE. When a tube with a solid structure containing PTFE is uniaxially stretched, fibrils are pulled out from the nodes roughly along the stretching direction. Nodes refer to areas where the polymer fibers are not stretched and the PTFE material is aggregated. Fibrils refer to polymer fibers that exist between nodes and are oriented along the stretching direction.

A large number of through holes (communication holes) are formed between nodes, between fibrils, and between nodes and fibrils. Since the wall surface of the first tube has at least a part of the porous structure having such a microstructure, only particles larger than the through hole pass through the part having the porous structure, and particles larger than the through hole pass through the part having the porous structure. It has the function of blocking the passage of small particles. Therefore, for example, by immersing a portion of the first tube having a porous structure in a chemical solution and injecting gas into the inner peripheral surface of the first tube, the gas is supplied into the chemical solution through the porous structure. At the same time, it is possible to prevent the chemical solution from entering the first tube.

Since the first tube has a cylindrical tube shape, it has flexibility. Therefore, it is easy to enter and place the first tube in a narrow or complicated place, and it is also easy to move the first tube within a stirring container filled with a chemical solution or the like. Further, there is an advantage that bending can be performed to match the required installation shape. That is, the degree of freedom in installing the bubbler tube including the first tube is high. Furthermore, since the first tube contains PTFE, it has excellent chemical resistance and heat resistance.

Hereinafter, a bubbler tube according to an embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an example of a bubbler tube.

The bubbler tube 10 includes a first tube 11 and a second tube 12. The bubbler tube 10 shown in FIG. 1 further includes a fluororesin-containing cap 16 at the end of the first tube 11, but the fluororesin-containing cap 16 can be omitted depending on the use of the bubbler tube 10. In FIG. 1, the symbol C indicates the center line of the bubbler tube 10.

The first tube 11 has a porous structure at least in part and contains polytetrafluoroethylene. The first tube 11 may be made of polytetrafluoroethylene. The first tube 11 is a tube extending from one end 110 to the other end 111. The first tube 11 has an inner peripheral surface 11a and an outer peripheral surface 11b. The first tube 11 is, for example, a cylindrical tube having a predetermined inner diameter and outer diameter.

For example, the porous structure portion included in the first tube 11 may occupy 50% by volume or more, 80% by volume or more, or 100% by volume of the first tube 11. good. In this specification and claims, a porous structure refers to a portion having a porosity of 5% or more. The upper limit of the porosity is, for example, 80%. The porosity is preferably within the range of 10% to 40%.

The first tube containing PTFE can also be used as a bubbling section for, for example, chemical solutions such as resists, developers, organic solvents, strong acids, and strong alkalis used in semiconductor manufacturing. In the bubbler tube 10 shown in FIG. 1, a portion of the first tube 11 whose outer peripheral surface 11b is exposed can function as a bubbling section 30. The bubbling portion 30 is a portion in which at least a portion of the outer peripheral surface has a porous structure. The bubbling portion 30 is, for example, a portion immersed in a chemical solution or the like. Portions other than the bubbling portion 30 may also be immersed in a chemical solution or the like.

When the first tube is immersed in a chemical solution, etc. and injected with air, there is no problem if the entire part of the porous structure is immersed in the chemical solution, etc., but if a part of the porous structure is not immersed in the chemical solution, etc. When the first tube is exposed to the atmosphere, there is a problem in that part of the gas supplied into the first tube ends up being released (leaked) into the atmosphere through this exposed portion.

FIG. 2 is a sectional view schematically showing a state in which a bubbler tube 50 according to a reference example is connected to a gas supply means. The bubbler tube 50 shown in FIG. 2 consists of only the first tube 11 which has a porous structure as a whole. The fitting 60 is directly connected to the end of the first tube 11 . The joint 60 includes, for example, a socket 61 and a plug 62. An end of the joint 60 on the side of the plug 62 is connected to a gas supply means (not shown). The socket 61 included in the joint 60 may be attached to a portion of the first tube 11 having a porous structure, for example. Here, as an example, a case is shown in which the entire first tube 11 has a porous structure, but as described above, at least a portion of the first tube 11 has a porous structure. That's fine.

When immersing the bubbler tube 50 according to the reference example shown in FIG. Do not immerse the product in water. The reason for this is, for example, because the chemical resistance of the joint 60 is poor compared to that of the first tube 11, so there is a risk that the joint 60 may be corroded by the chemical liquid or the like. In this case, since the entire first tube 11 having a porous structure is not immersed in the chemical solution, a portion of the gas injected into the first tube 11 from the gas supply means through the joint 60 is absorbed into the portion 15. There is a possibility that the liquid may leak out from the first tube 11 through the porous structure.

On the other hand, FIG. 3 is a sectional view schematically showing a state in which the bubbler tube 10 according to the embodiment is connected to a gas supply means. In the bubbler tube 10 shown in FIG. 3, the one end 120 side of the second tube 12 having a non-porous structure is connected to the one end 110 side of the first tube 11 via a fused portion 122. In the bubbler tube 10, a joint 60 is connected to the other end 121 of the second tube 12. The joint 60 includes, for example, a socket 61 and a plug 62. An end of the joint 60 on the side of the plug 62 can be connected to a gas supply means (not shown). Note that the bubbler tube 10 shown in FIG. 3 may or may not include the joint 60. As the joint 60, a known joint can be used.

The second tube 12 is a tube having a non-porous structure (solid structure). Therefore, even if the entire bubbling portion 30 of the first tube 11 whose outer circumferential surface 11b is exposed is immersed in a chemical solution or the like, the joint 60 will not come into contact with the chemical solution or the like. Moreover, the gas supplied into the bubbler tube 10 through the joint 60 does not leak from the wall surface of the second tube 12, which has a non-porous structure. Therefore, according to the bubbler tube 10 shown in FIG. 3, the gas supplied into the bubbler tube 10 from the joint 60 side is suppressed from leaking into the atmosphere, and the chemical liquid etc. is injected from the bubbling part 30. You can do it with care.

In addition, since the second tube 12 does not have a porous structure, the other end 121 of the second tube 12 can be fitted with various commonly used devices such as flanges and nuts, not limited to the joint 60. Or it can be easily processed. Therefore, the installation cost of the bubbler tube according to the embodiment is low. When such processing is performed directly on a tube with a porous structure, some additional processing is required to prevent gas leakage as described above or to reinforce the mechanical strength of the tube. Since this is necessary, there is a concern that the cost will increase.

(1st tube)
The inner diameter of the first tube 11 is not particularly limited, but is, for example, within a range of 0.5 mm to 30 mm. The outer diameter of the first tube 11 is not particularly limited, but is, for example, within a range of 0.7 mm to 40 mm. The wall thickness of the first tube 11 is, for example, within a range of 0.1 mm to 5.0 mm. The thickness of the wall surface of the first tube 11 is defined by the distance in the radial direction from the inner circumferential surface 11a of the first tube 11 to the nearest outer circumferential surface 11b.

The inner and outer diameters of the tube can be measured using a pin gauge or caliper with an accuracy of 1/1000 mm.

If the wall surface of the first tube 11 is excessively thick, the flexibility of the first tube 11 may become poor.

The apparent specific gravity of the first tube 11 alone is, for example, within a range of 0.10 to 2.0. The apparent specific gravity of the first tube 11 alone may be within the range of 0.11 to 1.87. It is desirable that the apparent specific gravity of the first tube 11 be larger than the specific gravity of the chemical solution or the like in which the first tube 11 is immersed. In this case, even if bubbling is performed while the first tube 11 is immersed in a chemical solution or the like, lifting of the first tube 11 can be suppressed. That is, it is possible to suppress a decrease in stirring efficiency due to bubbling. In this case, since there is no need to fix the first tube 11 from the outside, it is possible to increase the degree of freedom in installing the bubbler tube according to the embodiment. The specific gravity of the first tube 11 can be measured by measuring specific gravity using an underwater displacement method. Note that when the bubbling section 30 is composed of the first tube 11 alone, the apparent specific gravity of the first tube 11 may be the apparent specific gravity of the bubbling section 30.

The length of the first tube 11 is not particularly limited, but is, for example, within a range of 0.1 m to 5.0 m. The length of the first tube 11 refers to the length from one end 110 to the other end 111. If the length of the first tube 11 is excessively long, the gas pressure in the vicinity of the other end 111 of the first tube 11 decreases significantly compared to the vicinity of one end 110 of the first tube 11 near the gas inlet, which is not preferable. This tendency is particularly noticeable when the entire first tube 11 has a porous structure.

One way to suppress the increase in pressure loss near the other end 111 of the first tube 11 is to shorten the length of the first tube 11. Alternatively, when a third tube including a large number of solid structures is provided on the inner diameter side of the first tube 11 as in a second modification example described later, an increase in pressure loss can be suppressed.

The other end 111 of the first tube 11 may be one end 100 of the bubbler tube 10.

(Second tube)
The second tube 12 has a non-porous structure and contains fluororesin. The second tube may be made of fluororesin. The second tube 12 is a tube extending from one end 120 to the other end 121. The second tube 12 has an inner peripheral surface 12a and an outer peripheral surface 12b. The second tube 12 is, for example, a cylindrical tube having a predetermined inner diameter and outer diameter.

The non-porous structural portion included in the second tube 12 may, for example, occupy 50% by volume or more, 80% by volume or more, or 100% by volume of the second tube 12. Good too. In this specification and claims, a non-porous structure refers to a portion with a porosity of less than 5%. The lower limit of the porosity is not particularly limited, and may be 0%.

The inner diameter of the second tube 12 is not particularly limited, but is, for example, within the range of 0.7 mm to 40 mm. The outer diameter of the second tube 12 is not particularly limited, but is, for example, within the range of 1.3 mm to 50 mm. The inner diameter of the second tube 12 is preferably larger than the outer diameter of the first tube 11.

The wall thickness of the second tube 12 is, for example, within a range of 0.3 mm to 5.0 mm. The thickness of the wall surface of the second tube 12 is defined by the distance in the radial direction from the inner circumferential surface 12a of the second tube 12 to the nearest outer circumferential surface 12b.

The length of the second tube 12 is not particularly limited, but is, for example, within a range of 0.1 m to 5.0 m.

One end 120 side of the second tube 12 is connected to the one end 110 side of the first tube 11 . For example, on the one end 110 side of the first tube 11 and the one end 120 side of the second tube 12, a part of the outer peripheral surface 11b of the first tube 11 faces, for example, a part of the inner peripheral surface 12a of the second tube 12. are doing. The connection between the one end 120 of the second tube 12 and the one end 110 of the first tube 11 is such that, for example, as shown in FIG. This is done by fusing one end 120 of the second tube 12 to the outer peripheral surface 11b of the first tube 11. That is, one end 120 of the second tube 12 is fused to the outer circumferential surface 11b of the first tube 11 via the fused portion 122.

Preferably, one end 120 of the second tube 12 is not butted against one end 110 of the first tube 11. The fused portion 122 may be a portion where the second tube 12 itself is melted, or may be a portion containing a separately prepared melt-flowable fluororesin.

Examples of the fluororesin contained in the second tube 12 include polytetrafluoroethylene (PTFE), modified PTFE, perfluoroalkoxyalkane (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), and perfluoroethylene propene copolymer (FEP). and polyvinylidene fluoride (PVDF). The fluororesin contained in the second tube 12 is preferably PFA from the viewpoint of exhibiting excellent chemical resistance and heat resistance as well as an anchoring effect to the first tube 11.

The fused portion 122 may include at least one type of melt-flowable fluororesin selected from the group consisting of PFA, ETFE, FEP, and PVDF.

The other end 121 of the second tube 12 may be the other end 101 of the bubbler tube 10.

The entire length of the bubbler tube 10 is defined from the other end 111 of the first tube 11 to the other end 121 of the second tube 12. The total length of the bubbler tube 10 is not particularly limited, but is, for example, within a range of 0.2 m to 10 m. The bubbling portion 30 described above may be a portion of the entire length of the bubbler tube 10 where the outer peripheral surface 11b of the first tube 11 is exposed. The length of the bubbling section 30 is not particularly limited, but is, for example, within a range of 0.1 m to 5.0 m.

(Cap containing fluororesin)
The fluororesin-containing cap 16 shown in FIG. 1 can suppress the release of gas that may be released from the other end 111 of the first tube 11 to the outside of the bubbler tube 10. In other words, the fluororesin-containing cap 16 can seal the other end 111 of the first tube 11. The size and shape of the fluororesin-containing cap 16 are not particularly limited. Although not shown, the other end 111 of the first tube 11 may be sealed by ultrasonic welding with the edges of the tube overlapped, instead of being provided with the fluororesin-containing cap 16.

The fluororesin contained in the fluororesin-containing cap 16 is not particularly limited, but is, for example, a melt-flowable fluororesin. As the melt-flowable fluororesin, for example, the type described above for the fused portion 122 can be used.

(First modification)
The bubbler tube according to the embodiment can further include an intermediate layer 14. FIG. 4 is a cross-sectional view schematically showing an example in which the bubbler tube 10 further includes an intermediate layer 14. The intermediate layer 14 can also be called a spacer.

The bubbler tube 10 shown in FIG. 4 includes an intermediate layer 14 between the inner peripheral surface 12a of the second tube 12 and the outer peripheral surface 11b of the first tube 11, which is fused to both. The intermediate layer 14 may be formed, for example, at least in part of the portion where the inner circumferential surface 12a of the second tube 12 and the outer circumferential surface 11b of the first tube 11 face each other. A portion of the intermediate layer 14 may be further formed in a portion where the inner circumferential surface 12a of the second tube 12 and the outer circumferential surface 11b of the first tube 11 do not face each other. The intermediate layer 14 has, for example, a cylindrical shape that covers the outer peripheral surface 11b of the first tube 11.

The intermediate layer 14 includes, for example, a melt-flowable fluororesin. As the melt-flowable fluororesin contained in the intermediate layer 14, for example, at least one melt-flowable fluororesin selected from the group consisting of PFA, ETFE, FEP, and PVDF can be used.

The thickness of the intermediate layer 14 is not particularly limited, but is, for example, within a range of 0.005 mm to 5.0 mm. When the outer diameter of the first tube 11 is small and the inner diameter of the second tube 12 is large, the gap between the first tube 11 and the second tube 12 is reduced by forming an intermediate layer 14 having a relatively large thickness. It is effective to fill it in. Thereby, the formation of wrinkles and the like at the joint between the first tube 11 and the second tube 12 can be suppressed. Therefore, when used as a bubbler, it is possible to suppress gas leakage at the joint and intrusion of chemical liquid and the like into the tube. On the other hand, when the outer diameter of the first tube 11 is large and the inner diameter of the second tube 12 is small, it is not possible to fill the gap between the first tube 11 and the second tube 12 with the intermediate layer 14 having a relatively small thickness. can.

The presence of the intermediate layer 14 makes the bond between the first tube 11 and the second tube 12 stronger. Therefore, for example, even when the bubbler tube 10 is used in an installation method in which the bending radius becomes large, gas leakage from the joint between the first tube 11 and the second tube 12 can be suppressed. I can do it.

(Second modification)
The bubbler tube according to the embodiment may further include a third tube. FIG. 5 is a cross-sectional view schematically showing an example in which the bubbler tube 10 further includes a third tube 13. First, an example of the third tube will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view schematically showing an example of the third tube 13. FIG. 7 is a schematic cross-sectional view taken along line XII-XII in FIG. 6.

The third tube 13 is a tube at least partially having a non-porous structure (solid structure). The entire third tube 13 may have a non-porous structure. However, the third tube 13 has at least one through hole 132. The third tube 13 is a tube extending from one end 130 to the other end 131. The third tube 13 has an inner peripheral surface 13a and an outer peripheral surface 13b. The third tube 13 is, for example, a cylindrical tube having a predetermined inner diameter and outer diameter.

The non-porous structural portion included in the third tube 13 may occupy, for example, 50% by volume or more, 80% by volume or more, or 100% by volume of the third tube 13. Good too. However, the volume of the hollow portion formed by the through hole 132 is excluded here. That is, in the third tube 13, the above volume percentage is applied to the substantial portion other than the through hole 132.

The thickness of the wall surface of the third tube 13 is, for example, within a range of 0.1 mm to 5.0 mm. The thickness of the wall surface of the third tube 13 is defined by the distance in the radial direction from the inner circumferential surface 13a of the third tube 13 to the nearest outer circumferential surface 13b. If the wall surface of the third tube 13 is excessively thick, the tube may have poor flexibility. In order for the third tube 13 to have excellent flexibility, the thickness of the wall surface of the third tube 13 is preferably within the range of 0.5 mm to 1.5 mm.

It is preferable that the third tube 13 includes two or more through holes 132. The through hole 132 is a hole that penetrates the wall surface of the third tube 13. That is, the through hole 132 is a hole that penetrates from the inner circumferential surface 13a to the outer circumferential surface 13b. It is preferable that the two or more through holes 132 are arranged along the longitudinal direction of the third tube 13, that is, in the direction from one end 130 to the other end 131. The two or more through holes 132 do not need to be arranged along one direction.

Although the size of the through hole 132 is not particularly limited, the diameter of the hole is, for example, within a range of 0.1 mm to 5.0 mm.

When there are two or more through holes 132, the arrangement interval (distance between the centers of the holes) is not particularly limited, but is, for example, within the range of 10 mm to 500 mm. The two or more through holes 132 may be arranged at regular intervals, or may be arranged at arbitrary intervals. For example, the interval between two adjacent through holes 132 provided at a certain position is different from the interval between two adjacent through holes 132 provided at a different position. Good too.

The resin constituting the third tube 13 is not limited to fluororesin, and various thermoplastic resins and thermosetting resins can be used. From the viewpoint of chemical resistance and heat resistance, it is preferable that the third tube 13 contains a fluororesin. Examples of the fluororesin contained in the third tube 13 include polytetrafluoroethylene (PTFE), modified polytetrafluoroethylene, perfluoroalkoxyalkane (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), and perfluoroethylene propene copolymer ( FEP) and polyvinylidene fluoride (PVDF).

Next, the bubbler tube 10 including the third tube 13 described above will be described with reference to FIG. 5. The bubbler tube 10 shown in FIG. 5 has the same configuration as the bubbler tube 10 shown in FIG. 4 except that it further includes a third tube 13.

The third tube 13 is arranged on the inner diameter side of the first tube 11. Therefore, the outer diameter of the third tube 13 may be smaller than the inner diameter of the first tube 11. At least a portion of the outer peripheral surface 13b of the third tube 13 is fused to the inner peripheral surface 11a of the first tube 11 via the fusion layer 20. A tube having a two-layer structure of the third tube 13 and the first tube 11 can also be called a composite tube.

The thickness of the wall surfaces of the first tube and the third tube in the composite tube can be measured by observing a cross section of the composite tube with a scanning electron microscope (SEM). Specifically, it is determined by preparing at least five cross sections of the tube to be measured and calculating a simple average of the measured values for each cross section.

In FIG. 5, as an example, the fusion layer 20a fuses the vicinity of one end 110 of the first tube 11 and the vicinity of one end 130 of the third tube 13. Further, the fusion layer 20b fuses the vicinity of the other end 111 of the first tube 11 and the vicinity of the other end 131 of the third tube 13.

The fusion layers 20a and 20b are each provided in an annular shape on the outer circumferential surface 13b of the third tube 13.

The adhesive layer 20 includes, for example, a melt-flowable fluororesin. The melt-flowable fluororesin is, for example, at least one selected from the group consisting of perfluoroalkoxyalkane (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoroethylene propene copolymer (FEP), and polyvinylidene fluoride (PVDF). Examples include seeds.

At least a portion of the outer peripheral surface 11b of the first tube 11 faces the inner peripheral surface 12a of the second tube 12 with the intermediate layer 14 in between. Therefore, the outer diameter of the first tube 11 may be smaller than the inner diameter of the second tube 12.

Of the entire length of the bubbler tube 10, in a composite tube formed by laminating the first tube 11 and the third tube 13, a portion where the outer circumferential surface 11b of the first tube 11 is exposed can function as the bubbling portion 30.

The apparent specific gravity of the bubbling portion 30 in the composite tube may be within the range of 0.10 to 2.0, or may be within the range of 0.11 to 1.87. It is desirable that the apparent specific gravity of the bubbling section 30 be larger than, for example, the specific gravity of the chemical solution or the like in which the bubbling section 30 is immersed. In this case, even if bubbling is performed while the bubbling part 30 is immersed in a chemical solution or the like, it is possible to suppress the bubbling part 30 from floating up. The apparent specific gravity of the bubbling section 30 can be measured by measuring specific gravity using an underwater displacement method.

The other end 111 of the first tube 11 and the other end 131 of the third tube 13 may be one end 100 of the bubbler tube 10. The other end 121 of the second tube 12 may be the other end 101 of the bubbler tube 10. The entire length of the bubbler tube 10 is defined, for example, from the other end 111 of the first tube 11 to the other end 121 of the second tube 12.

As shown in FIG. 5, when the third tube 13 is arranged on the inner diameter side of the first tube 11, even if the first tube 11 becomes long, It is possible to suppress an increase in pressure loss of the gas flowing in. Specifically, for example, gas flowing into the bubbler tube 10 from the other end 121 of the second tube 12 mainly passes through the third tube 13 and reaches the one end 100 of the bubbler tube 10. Although the third tube 13 has at least one through hole 132, its inner peripheral surface 13a has a non-solid structure, for example. Therefore, pressure loss can be reduced compared to the case where gas flows directly inside the first tube 11 having a porous structure.

The gas flowing in the third tube 13 passes through the through hole 132 from the inner circumferential surface 13a side of the third tube 13 and between the outer circumferential surface 13b of the third tube 13 and the inner circumferential surface 11a of the first tube 11. The liquid then passes through the porous structure of the first tube 11 and is discharged to the outside of the first tube 11. Since the third tube 13 is provided, gas can be released relatively uniformly from the entire outer circumferential surface 11b of the first tube 11.

(Production method)
An example of a method for manufacturing a bubbler tube according to an embodiment will be described below.
The first tube can be manufactured, for example, by uniaxially stretching a PTFE tube having a non-porous structure (solid structure). The solid-structured PTFE tube that is the precursor of the first tube can be, for example, an extrusion. An example of extrusion molding will be described below.

As raw materials for the extrusion molded product, PTFE fine powder and an extrusion aid such as a lubricant can be used. A paste-like mixture can be obtained by mixing an extrusion aid such as a lubricant with PTFE fine powder. A tube-shaped extruded product can be obtained by extruding a mixture containing PTFE fine powder into a tube shape.

Examples of extrusion aids include commonly used solvent naphtha (e.g., registered trademark: Isoper E, manufactured by Exxon Chemical Co., Ltd.), white oil, and liquid paraffin having 6 to 12 carbon atoms (e.g., registered trademark: Cactus Normal). Paraffin N-10 (manufactured by Japan Energy Co., Ltd.) can be mentioned.

The mixture obtained by mixing the PTFE fine powder and the extrusion aid may be aged before being subjected to extrusion molding. Alternatively, a compression molded body (billet) may be produced by compressing the aged mixture. Compression can remove air in the PTFE fine powder and improve the uniformity of the extruded product. The shape of the compression molded body is not particularly limited, but may be, for example, cylindrical.

Subsequently, the PTFE tube produced as the first tube precursor is uniaxially stretched. When uniaxial stretching is performed, polymer fibers are pulled out from the polymer material contained in the first tube precursor and stretched in the stretching direction. In this way, a fine structure including nodes and fibrils can be formed.

By adjusting the stretching ratio during uniaxial stretching, the specific gravity or porosity of the first tube can be adjusted. By increasing the stretching ratio during uniaxial stretching, a first tube having a low specific gravity can be formed. By lowering the stretching ratio during uniaxial stretching, a first tube having a high specific gravity can be formed. For example, if the stretching ratio during uniaxial stretching is doubled, a first tube with a porosity of approximately 50% can be manufactured. The stretching ratio can be adjusted as appropriate depending on the desired specific gravity, and is, for example, within the range of 1.2 times to 6 times. It can be adjusted as appropriate depending on the desired specific gravity.

Subsequently, the unfired first tube is dried and fired. Drying is performed, for example, in a drying oven. By drying at a temperature higher than the boiling point of the previously used petroleum extrusion aid, the aid can be volatilized. Subsequently, the dried tube is fired by heating at a temperature equal to or higher than the melting point of PTFE, for example, at a temperature equal to or higher than 330°C. In this way, the first tube can be manufactured.

The second tube having a non-porous structure is manufactured using, for example, the above-mentioned fluororesin. The second tube can be manufactured by a known molding method such as extrusion molding or injection molding.

The inner diameter and outer diameter of the first tube and the inner diameter and outer diameter of the second tube can be designed and manufactured to desired values. As mentioned above, in one example, the inner diameter of the second tube is made larger than the outer diameter of the first tube.

One end of the produced first tube is inserted into one end of the second tube, and heat treatment is performed at a temperature higher than the melting point of the fluororesin constituting the second tube, so that the one end of the second tube becomes the outer periphery of the first tube. Can be fused onto a surface. Thereby, for example, the bubbler tube 10 having the fused portion 122 described with reference to FIG. 1 can be manufactured.

Moreover, when manufacturing the bubbler tube 10 further including the intermediate layer 14 described with reference to FIG. 4, it can be manufactured, for example, as follows.

After producing the first tube, a dispersion containing fluororesin particles for forming the intermediate layer 14 is produced. As the fluororesin particles, it is preferable to use the above-mentioned melt-flowable fluororesin particles.

The dispersion includes a dispersion medium and a melt-flowable fluororesin powder in the dispersion medium. As the melt-flowable fluororesin powder, it is possible to use a material commonly used in a method of forming a resin tube by coating, such as a dip coating method. For example, a dispersion is an aqueous dispersion in which melt-flowable fluororesin powder is dispersed in an aqueous dispersion medium by emulsion polymerization.

The dispersion medium can be, for example, water. The composition of the dispersion is not particularly limited, and for example, a dispersion or suspension having a composition commonly used in techniques such as dip coating can be used. The dispersion may or may not further contain fillers or additives different from the melt-flowable fluororesin powder.

The prepared dispersion is applied to a part of the outer peripheral surface of the first tube to form a coating film. Next, one end of the first tube is inserted into one end of the second tube, and at least a portion of the coating is covered with the inner peripheral surface of the second tube. Thereafter, the joint portion of the first tube and the second tube is subjected to heat treatment. In this way, the intermediate layer can be formed in at least a portion of the portion where the outer circumferential surface of the first tube and the inner circumferential surface of the second tube face each other.

Moreover, the bubbler tube 10 further including the third tube described with reference to FIG. 5 can be produced, for example, by the following method.

First, a third tube is produced. The third tube can be produced, for example, by forming desired through holes with a drill or the like in a resin tube having a non-porous structure produced by a known molding method such as extrusion molding or injection molding. . When a plurality of through holes are provided in the third tube, these through holes may or may not be arrayed along one direction.

Next, the produced third tube is combined with the first tube. Specifically, first, a dispersion containing melt-flowable fluororesin particles is applied to the outer peripheral surface of the third tube near one end and the other end of the third tube. As this dispersion, those mentioned above can be used. After that, a third tube is inserted into the inner diameter side (inner peripheral surface side) of the first tube and is subjected to heat treatment, thereby melting the fluororesin particles contained in the coating film and forming a fusion layer. . In this way, a composite tube having a two-layer structure of the third tube 13 and the first tube 11 can be manufactured.

Subsequently, the second tube is joined onto the outer peripheral surface of the first tube combined with the third tube in the same manner as described above. In this way, a bubbler tube further including the third tube can be produced.

In the bubbler tube according to the embodiment, either one of the first modification and the second modification may be employed, or both of these may be employed. Furthermore, it is not necessary to employ both the first modification example and the second modification example.

(Second embodiment)
According to the second embodiment, a bubbler including the bubbler tube according to the first embodiment and a gas supply means is provided. The gas supply means is connected to the other end of the second tube included in the bubbler tube according to the first embodiment. Although not shown, the bubbler may be equipped with two gas supply means. That is, gas supply means may be provided at one end and the other end of the bubbler tube, respectively.

The type of gas supply means is not particularly limited. The gas supply means may be a conventionally known device. The gas supply means is, for example, a device capable of emitting a gaseous material at a constant supply amount per unit time. The gaseous material can be supplied from the device through the gas supply pipe into the bubbler tube according to the first embodiment.

The type of gas to be supplied can be changed as appropriate depending on the purpose of the bubbler, and is, for example, at least one type selected from the group consisting of air, nitrogen, ozone gas, ammonia, and the like.

FIG. 8 is a diagram schematically showing an example of the bubbler according to the embodiment. In the bubbler shown in FIG. 8, a gas supply means 40 is connected to the other end of the second tube 12 provided in the bubbler tube via a gas supply pipe 41. A device such as a one-touch joint may be installed at the connection between the other end of the second tube 12 and the gas supply pipe 41, if necessary.

The first tube 11 of the bubbler tube is immersed in a liquid material 43 stored in a container 42 . In this state, by supplying gas from the gas supply means 40 into the bubbler tube, the gas can be diffused into the liquid material 43 through the wall surface of the first tube 11 having a porous structure. That is, bubbling can be performed.

The type of liquid material can be changed as appropriate depending on the purpose of the bubbler, and may include, for example, resists used in semiconductor manufacturing, developers, organic solvents, various aqueous solutions, strong acids, strong alkalis, and the like. An example of the various aqueous solutions includes an aqueous sodium hypochlorite solution.

It is preferable that the apparent specific gravity of the above-mentioned bubbling portion, that is, the portion of the entire length of the bubbler tube where the outer circumferential surface of the first tube 11 is exposed, is greater than that of the liquid material 43. In this case, it is possible to prevent the bubbling portion from floating near the liquid surface and reducing the efficiency of stirring the liquid material due to bubbling.

The bubbler according to the second embodiment includes the bubbler tube according to the first embodiment. For example, since the bubbling section constituted by the first tube 11 has a tube shape, it can be easily bent to match the installation shape and moved within the liquid material 43 stored in the container 42. . That is, according to the second embodiment, a bubbler that is excellent in chemical resistance and heat resistance, and has a high degree of freedom in installation is provided.

Note that the present invention is not limited to the above-described embodiments, and can be variously modified at the implementation stage without departing from the gist thereof. Moreover, each embodiment may be implemented in combination as appropriate, and in that case, the combined effect can be obtained. Furthermore, the embodiments described above include various inventions, and various inventions can be extracted by combinations selected from the plurality of constituent features disclosed. For example, if a problem can be solved and an effect can be obtained even if some constituent features are deleted from all the constituent features shown in the embodiment, the configuration from which these constituent features are deleted can be extracted as an invention.

DESCRIPTION OF SYMBOLS 10... Bubbler tube, 11... First tube, 11a... Inner circumferential surface, 11b... Outer circumferential surface, 12... Second tube, 12a... Inner circumferential surface, 12b... Outer circumferential surface, 13... Third tube, 13a... Inner circumference Surface, 13b... Outer peripheral surface, 14... Intermediate layer, 16... Fluororesin-containing cap, 20... Fusion layer, 30... Bubbling section, 40... Gas supply means, 41... Gas supply pipe, 42... Container, 43... Liquid material , 60... Joint, 61... Socket, 62... Plug, 122... Fusion part, 132... Through hole.

Claims (8)

a first tube at least partially having a porous structure and containing polytetrafluoroethylene;
It has a non-porous structure and includes a second tube containing a fluororesin,
One end of the second tube is a bubbler tube connected to one end of the first tube. A portion of the outer circumferential surface of the first tube faces a portion of the inner circumferential surface of the second tube,
The bubbler tube according to claim 1, further comprising an intermediate layer interposed between the outer peripheral surface of the first tube and the inner peripheral surface of the second tube. further comprising a third tube having an inner circumferential surface and an outer circumferential surface,
The first tube covers at least a portion of the outer circumferential surface of the third tube, and at the one end and the other end of the first tube, the inner circumferential surface of the first tube covers at least a portion of the outer circumferential surface of the third tube. It is fused to the outer peripheral surface via a fusion layer,
Claim 1: The third tube has a plurality of through holes that penetrate from the inner circumferential surface to the outer circumferential surface and are arranged in a direction from one end of the third tube to the other end. Or the bubbler tube according to 2. Of the entire length of the bubbler tube defined from the other end of the first tube to the other end of the second tube, a portion where the outer peripheral surface of the first tube is exposed is a bubbling portion,
The tube for a bubbler according to claim 1 or 2, wherein the apparent specific gravity of the bubbling portion is within a range of 0.10 to 2.0. The tube for a bubbler according to claim 1 or 2, wherein the length of the first tube is within a range of 0.1 m to 5.0 m. Further equipped with a fluororesin-containing cap,
The bubbler tube according to claim 1 or 2, wherein the other end of the first tube is sealed by the fluororesin-containing cap. A bubbler tube according to claim 1 or 2,
and a gas supply means,
The gas supply means is a bubbler connected to the other end of the second tube. A bubbler for bubbling liquid material,
Of the entire length of the bubbler tube defined from the other end of the first tube to the other end of the second tube, a portion where the outer peripheral surface of the first tube is exposed is a bubbling portion,
The bubbler according to claim 7, wherein the apparent specific gravity of the bubbling portion is greater than the specific gravity of the liquid material.