Multi-layer pipe

Abstract

To provide a pipe for semiconductor cleaning liquid that can suppress an elution amount of calcium and organic components to a level that satisfies quality requirements of semiconductor cleaning liquid, and can be used as a pipe having mechanical characteristics at 60°C.SOLUTION: A pipe for semiconductor cleaning liquid of the present invention comprises a first polyolefin resin layer constituting the innermost layer, and a second polyolefin resin layer arranged on the outside of the first polyolefin resin layer, where an elution amount of calcium from the first polyolefin resin layer measured in accordance with SEMI F-57 is less than 30 μg / m2, and a thickness of the first polyolefin resin layer is 0.06 to 0.95 mm. This configuration can suppress an elution amount of calcium and organic substance to a level that satisfies quality requirements of semiconductor cleaning liquid, and can be used as a pipe having strength required for a use environment of 60°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-layer pipe, and more specifically, to a polyolefin resin pipe used as a piping for semiconductor cleaning liquid. [Background technology]

[0002] Conventionally, in the manufacture of semiconductor precision devices, ultrapure water refined to an extremely high degree of purity and ultra-high purity cleaning solutions refined to an extremely high degree of purity with the necessary components have been used as semiconductor cleaning solutions in wet processes such as cleaning. If metal ions and / or organic substances are present in a semiconductor cleaning solution at a concentration above a certain level, the metals and / or organic substances are adsorbed onto the wafer surface or the like, adversely affecting the quality of the precision device, and therefore, the impurities in semiconductor cleaning solutions such as ultrapure water and high purity cleaning solutions are strictly restricted.

[0003] Impurities can also get mixed into the semiconductor cleaning solution in the piping that constitutes the transport line of the semiconductor cleaning solution. Although metals such as stainless steel, which have excellent gas barrier properties, have been used as the material for the piping, it is considered preferable to use resin in consideration of the influence of metal elution from the piping.

[0004] Resins used as materials for semiconductor cleaning liquid piping are fluororesins that are chemically inactive, have gas barrier properties, and are very little eluted into semiconductor cleaning liquids. For example, Patent Document 1 discloses a fluororesin double tube, in which two layers of fluororesin are laminated, as piping used in semiconductor manufacturing equipment, in which an inner layer tube is made of a fluororesin that is excellent in corrosion resistance and chemical resistance (e.g., tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or tetrafluoroethylene-ethylene copolymer (ETFE)), and an outer layer tube is made of a fluororesin that can suppress gas permeation (e.g., polyvinylidene fluoride (PVDF)). Patent Document 2 discloses a multi-layer pipe for piping ultrapure water, characterized in that it comprises a first resin layer made of a fluororesin that comes into contact with the ultrapure water, and a second resin layer made of a gas-impermeable resin that is provided on the outer peripheral surface of the first resin layer, and further discloses that a third resin layer that protects the second resin layer is provided on the outer peripheral surface of the second resin layer, and that polyethylene is used for the third resin layer.

[0005] Among the resins used as materials for piping for semiconductor cleaning solutions, polyvinylidene fluoride (PVDF) is used in all practical applications in the semiconductor industry, such as piping within semiconductor cleaning solution manufacturing equipment and piping for transporting semiconductor cleaning solutions from semiconductor cleaning solution manufacturing equipment to use points, and has become the technical standard for semiconductor cleaning solution piping.

[0006] Recently, with the increase in the integration density of semiconductor chips, circuit patterns have become finer and finer, making them more susceptible to even low-level impurities. Therefore, the quality requirements for semiconductor cleaning fluids have become increasingly strict. For example, the standard for the quality of semiconductor cleaning fluids used in semiconductor manufacturing has been published as SEMI F75, and is updated every two years. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-299808 A [Patent Document 2] JP 2010-234576 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the context of increasingly strict quality requirements for semiconductor cleaning fluids, fluororesin piping such as PVDF is the only option that meets the required water quality, and its outstanding performance is strongly supported. However, due to the special nature of its use, it is disadvantageous in terms of construction and cost compared to other general piping. In addition, there are problems such as rapid deterioration because ultra-high purity cleaning fluids often contain diaminoalkanes such as 3-diaminopropane and are used under conditions of 60°C.

[0009] Therefore, the present inventors have dared to focus on replacing the material of the pipe for the semiconductor cleaning liquid. Specifically, in view of the fact that polyolefin-based resins, which are excellent in workability and cost, are used as general piping materials, the inventors have attempted to replace the material of the pipe for the semiconductor cleaning liquid with polyolefin-based resins.

[0010] However, polyolefin resins, which are widely used as piping materials, are synthesized by polymerization using a chlorine-based catalyst, and it is necessary to mix neutralizing agents such as calcium stearate and hydrocalcite to neutralize the catalyst residue after polymerization. For this reason, polyolefin resin pipes dissolve calcium and organic substances derived from the neutralizing agent into the water they transport. Furthermore, the level of dissolution of these calcium and organic substances is far below the quality required for semiconductor cleaning fluids.

[0011] The inventors attempted to dramatically reduce the amount of calcium and organic matter elution to a level that had previously only been achieved with fluororesin piping such as PVDF by using a material for polyolefin resin pipes in which the amount of neutralizing agent added to the catalyst in the polyolefin resin is extremely small compared to the original amount intended for neutralizing the catalyst residue. However, on the other hand, the inventors also faced a new problem in that the catalyst residue in such polyolefin resins maintains its activity, accelerating oxidative deterioration, and as a result, the mechanical strength (specifically, long-term durability against internal pressure) that piping should have cannot be met, and the deterioration is particularly noticeable in the environment of semiconductor cleaning solutions at 60°C.

[0012] In other words, it was found that if the material for semiconductor cleaning solution piping is replaced with polyolefin-based resin, there is a unique issue in that it is not possible to simultaneously suppress the amount of calcium and organic substance elution to a level that satisfies the required quality of semiconductor cleaning solution and to create piping with mechanical properties that take into account the 60°C usage environment.

[0013] In view of the above, an object of the present invention is to provide a piping for a semiconductor cleaning liquid made of a polyolefin resin, which suppresses the amount of calcium and organic substance elution to a level that satisfies the required quality of a semiconductor cleaning liquid, and which can be used as a piping having mechanical properties (specifically, this refers to long-term durability against internal pressure; hereinafter, this may also be simply referred to as strength) that take into account a usage environment of 60°C. [Means for solving the problem]

[0014] As a result of intensive research, the present inventors have found that by forming a polyolefin resin pipe into a multi-layer structure, disposing an inner layer of a polyolefin resin layer made of a polyolefin resin material that suppresses the amount of calcium and organic substance elution to a predetermined amount, and designing the thickness of the inner layer of the polyolefin resin layer to be within a predetermined range, it is possible to obtain a pipe that has mechanical properties that take into account the usage environment of 60°C while suppressing the amount of calcium and organic substance elution to a level that satisfies the required quality of a semiconductor cleaning solution. The present invention has been completed based on this finding and through further research. That is, the present invention provides the following aspects.

[0015] Item 1. A thermal insulation film comprising a first polyolefin-based resin layer constituting an innermost layer and a second polyolefin-based resin layer disposed on the outer side of the first polyolefin-based resin layer, The amount of calcium elution of the first polyolefin resin layer measured in accordance with SEMI F-57 is 30 μg / m 2 is less than The pipe for a semiconductor cleaning liquid, wherein the first polyolefin resin layer has a thickness of 0.06 to 0.95 mm. Item 2. The pipe for a semiconductor cleaning liquid according to Item 1, wherein a ratio of a thickness of the first polyolefin resin layer to a total thickness of the first polyolefin resin layer and the second polyolefin resin layer is 0.011 or more. Item 3. The pipe for a semiconductor cleaning liquid according to Item 1 or 2, wherein a ratio of a thickness of the first polyolefin resin layer to a total thickness of the first polyolefin resin layer and the second polyolefin resin layer is 0.17 or less. Item 4. The amount of calcium elution of the second polyolefin resin layer measured in accordance with SEMI F-57 is 30 μg / m 2 4. The pipe for a semiconductor cleaning liquid according to any one of Items 1 to 3, which is as described above. Item 5. The pipe for a semiconductor cleaning liquid according to any one of Items 1 to 4, wherein in an integrated molecular weight distribution curve of the first polyolefin resin layer measured by gel permeation chromatography, a proportion of components having a molecular weight of 1000 or less is 0.15% or more. Item 6. The pipe for a semiconductor cleaning liquid according to any one of Items 1 to 5, further comprising a gas barrier layer on the outside of the second polyolefin resin layer. Item 7. The pipe for a semiconductor cleaning liquid according to any one of Items 1 to 6, wherein the semiconductor cleaning liquid is used in a wet processing step of a semiconductor element having a minimum line width of 65 nm or less. Item 8. A thermal insulation film comprising a first polyolefin-based resin layer constituting an innermost layer and a second polyolefin-based resin layer disposed on the outer side of the first polyolefin-based resin layer, The amount of calcium elution of the first polyolefin resin layer measured in accordance with SEMI F-57 is 30 μg / m 2 is less than The first polyolefin resin layer has a thickness of 0.06 to 0.95 mm. Effect of the Invention

[0016] The polyolefin resin piping for semiconductor cleaning liquid of the present invention can suppress the amount of calcium and organic substances eluted to a level that satisfies the quality requirements for semiconductor cleaning liquid, and can provide piping that has the strength required for use in an environment of 60°C. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a semiconductor cleaning liquid pipe according to the present invention. [Diagram 2] FIG. 4 is a schematic cross-sectional view showing another example of the semiconductor cleaning liquid pipe of the present invention. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing still another example of the semiconductor cleaning liquid pipe of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [1. Piping Layer Configuration] The semiconductor cleaning liquid piping of the present invention includes a first polyolefin resin layer constituting the innermost layer and a second polyolefin resin layer disposed on the outside of the first polyolefin resin layer, and is used for transporting a semiconductor cleaning liquid (i.e., ultrapure water and / or a high-purity cleaning liquid). Examples of the semiconductor cleaning liquid piping of the present invention are shown in Figures 1 to 3.

[0019] The semiconductor cleaning liquid pipe 100 shown in Fig. 1 includes a first polyolefin-based resin layer 210 and a second polyolefin-based resin layer 220. The first polyolefin-based resin layer 210 constitutes the innermost layer of the semiconductor cleaning liquid pipe 100, and the second polyolefin-based resin layer 220 is laminated in contact with the first polyolefin-based resin layer 210. The semiconductor cleaning liquid pipe 100a shown in Fig. 2 includes a first polyolefin-based resin layer 210a and a second polyolefin-based resin layer 220. The first polyolefin-based resin layer 210a has a multi-layer structure. Although not shown, the semiconductor cleaning liquid pipe of the present invention may include a first polyolefin resin layer having a single layer structure and a second polyolefin resin layer having a multilayer structure; may include a first polyolefin resin layer having a multilayer structure and a second polyolefin resin layer having a multilayer structure; or may include another layer between the first polyolefin resin layer 210 and the second polyolefin resin layer 220. The semiconductor cleaning liquid pipe 100b shown in FIG. 3 includes the first polyolefin resin layer 210, the second polyolefin resin layer 220, and a gas barrier layer 300. The gas barrier layer 300 may be laminated on the outside of the second polyolefin resin layer 220. The gas barrier layer 300 may constitute the outermost layer of the semiconductor cleaning liquid pipe 100b, or another layer may be provided further outside the gas barrier layer 300.

[0020] [2. First polyolefin resin layer] The polyolefin resin constituting the first polyolefin resin layer is not particularly limited, and may be a polymer containing a monomer unit derived from an olefin. Examples include polyethylene resins, ethylene-alkenyl carboxylate ester copolymer resins, ethylene-α-olefin copolymer resins, polypropylene resins, polybutene resins, and poly(4-methyl-1-pentene) resins. These polyolefin resins may be used alone or in combination of two or more. Among these polyolefin resins, polyethylene resins and polypropylene resins are preferred from the viewpoint of improving the strength of the semiconductor cleaning liquid pipe. Furthermore, among the polyethylene resins and polypropylene resins, polyethylene resins are more preferred from the viewpoint of suppressing the content of low molecular weight components and suppressing the elution of organic components into ultrapure water.

[0021] The polyethylene resin is not particularly limited, but examples thereof include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), etc. Among these, high-density polyethylene (HDPE) is preferred from the viewpoint of suppressing the elution of organic components into ultrapure water.

[0022] Examples of the alkenyl carboxylate in the ethylene-alkenyl carboxylate copolymer resin include vinyl acetate, vinyl propionate, vinyl butyrate, isopropenyl acetate, and allyl acetate, and preferably vinyl acetate.

[0023] Examples of ethylene-α-olefin copolymers include copolymers in which ethylene is copolymerized with an α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, or 1-octene as a copolymerization component at a ratio of about several mol %.

[0024] Examples of polypropylene resins include homopolypropylene, block polypropylene, and random polypropylene. The copolymerization component in block polypropylene and random polypropylene usually includes ethylene. Examples of polybutene resins include polybutene-1.

[0025] The proportion of components with a molecular weight of 1000 or less in an integrated molecular weight distribution curve measured by gel permeation chromatography (polystyrene equivalent) of the polyolefin resin used in the first polyolefin resin layer is, for example, 0.15% or more. From the viewpoint of obtaining good processability during pipe molding, the above proportion is preferably 0.45% or more, more preferably 0.65% or more, and even more preferably 0.7% or more. The upper limit of the above proportion is not particularly limited, but is, for example, 0.9% or less, preferably 0.8% or less.

[0026] The molecular weight of the polyolefin resin used in the first polyolefin resin layer is not particularly limited, and may be, for example, 1×10 as the weight average molecular weight Mw. 5 ~7×10 5 In order to suppress the elution of organic components into ultrapure water and obtain surface smoothness, for example, a weight average molecular weight Mw of 1×10 5 ~5×10 5 , preferably 2 x 10 5 ~3×10 5 The weight average molecular weight Mw is a value measured by gel permeation chromatography in terms of polystyrene.

[0027] The molecular weight distribution (Mw / Mn) of the polyolefin resin used in the first polyolefin resin layer is 2 or more, for example, 2 to 30, from the viewpoint of processability during pipe molding. Furthermore, from the viewpoint of suppressing the elution of organic components into ultrapure water, the molecular weight distribution (Mw / Mn) is preferably 2 to 20. From the viewpoint of obtaining these effects more effectively, the molecular weight distribution (Mw / Mn) of the polyolefin resin used in the first polyolefin resin layer is preferably 2 to 15, more preferably 2 to 10, even more preferably 2 to 7, and even more preferably 3 to 6. The molecular weight distribution (Mw / Mn) is a value (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene by gel permeation chromatography measurement.

[0028] The amount of calcium elution of the material (polyolefin resin composition) of the first polyolefin resin layer, measured in accordance with EMI F-57, is 30 μg / m 2 The amount of calcium elution is less than 30 μg / m 2 If a material having a calcium solubility of 200 μg / m or more is used, the amount of calcium eluted into the semiconductor cleaning liquid during use of the semiconductor cleaning liquid piping becomes excessive, and the required quality of the semiconductor cleaning liquid cannot be met. From the viewpoint of further suppressing the amount of calcium eluted into the semiconductor cleaning liquid, the amount of calcium eluted from the material of the first polyolefin-based resin layer is preferably 29 μg / m 2 Less than or equal to 28 μg / m 2 The lower the amount of calcium elution from the material of the first polyolefin resin layer, the more preferable it is. Therefore, the most preferable lower limit is 0 μg / m 2 However, when a chlorine-based catalyst such as a Ziegler-Natta catalyst is used in the synthesis of the polyolefin resin used in the first polyolefin resin layer, and a small amount of neutralizing agent is further used, it is inevitable that a small amount of calcium is mixed in. In this case, the amount of calcium elution from the material of the first polyolefin resin layer is, for example, 1 μg / m 2 More than 5μμg / m 2 More than 10μg / m 2 More than 15μg / m 2More than 20μg / m 2 or more than 25 μg / m 2 The above can be mentioned.

[0029] The calcium concentration in the material (polyolefin resin composition) of the first polyolefin resin layer is not particularly limited as long as it satisfies the above calcium elution amount, but may be, for example, 10 ppm or less. From the viewpoint of further suppressing the amount of calcium elution into the semiconductor cleaning solution, the calcium concentration in the material of the first polyolefin resin layer is preferably 5 ppm or less, more preferably 3 ppm or less, and even more preferably 1 ppm or less. The lower the calcium concentration in the first polyolefin resin layer, the less calcium elution into ultrapure water, so from this viewpoint, the most preferable is 0 ppm. However, when a chlorine-based catalyst such as a Ziegler-Natta catalyst is used in the synthesis of the polyolefin resin used in the first polyolefin resin layer and a small amount of neutralizing agent is used, in the case where the inclusion of a trace amount of calcium is unavoidable, the calcium concentration in the first polyolefin resin layer may be, for example, 0.3 ppm or more, or 0.5 ppm or more.

[0030] The amount of organic components (total organic carbon; TOC) eluted from the material (polyolefin resin composition) of the first polyolefin resin layer, as measured in accordance with EMI F-57, is, for example, 800 μg / m 2 From the viewpoint of further suppressing the amount of organic components eluted into the semiconductor cleaning solution, the amount of organic components eluted from the material of the first polyolefin-based resin layer is preferably 600 μg / m 2 Less than or equal to 400 μg / m 2 Less than 360 μg / m 2 The lower the amount of organic components eluted from the material of the first polyolefin resin layer, the more preferable it is. Therefore, the most preferable lower limit is 0 μg / m 2 is However, when a chlorine-based catalyst such as a Ziegler-Natta catalyst is used in the synthesis of the polyolefin resin used in the first polyolefin resin layer, and a small amount of a neutralizing agent is further used, the inclusion of a small amount of organic components is unavoidable. In such a case, the amount of organic components eluted from the material of the first polyolefin resin layer is, for example, 5 μg / m 2 More than 10μμg / m 2 More than 100μg / m 2 More than 200μg / m 2 or more than 300μg / m 2 The above can be mentioned.

[0031] In addition, when the first polyolefin resin layer 210a is multi-layered, such as in the semiconductor cleaning liquid pipe 100a, the calcium elution amount, calcium concentration, and / or organic component elution amount of the material of the innermost layer of the multi-layered first polyolefin resin layer 210a can be designed to be lower than the materials of the other layers of the first polyolefin resin layer 210a.

[0032] In addition, by providing a degassing device for removing oxygen in the semiconductor cleaning liquid pipe, an antioxidant is not required in the first polyolefin resin layer. By not including an antioxidant in the first polyolefin resin layer, it is possible to further suppress the elution of organic components into the ultrapure water. In addition, the unnecessary antioxidant is not particularly limited as long as it is one used in ordinary polyolefin resins, and examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, aromatic amine-based antioxidants, and lactone-based antioxidants.

[0033] The thickness t1 of the first polyolefin resin layer is 0.06 to 0.95 mm. If the thickness t1 of the first polyolefin resin layer is less than 0.06 mm, the migration of calcium and organic components contained in the second polyolefin resin layer into the semiconductor cleaning liquid during use cannot be sufficiently prevented, and the amount of calcium and organic components eluted into the semiconductor cleaning liquid becomes excessive, making it impossible to meet the required quality of the semiconductor cleaning liquid. If the thickness t1 of the first polyolefin resin layer exceeds 0.95 mm, the strength of the semiconductor cleaning liquid pipe cannot be ensured in a 60°C operating environment.

[0034] From the viewpoint of further suppressing the amount of calcium and organic components eluted into the semiconductor cleaning liquid, the lower limit of the thickness t1 range of the first polyolefin resin layer is preferably 0.1 mm or more. Also, depending on the thickness of the second polyolefin resin layer, for example, when the thickness t2 of the second polyolefin resin layer is 4 mm or more, from the viewpoint of further suppressing the amount of calcium and organic components eluted into the semiconductor cleaning liquid, the lower limit of the thickness t1 range of the first polyolefin resin layer is more preferably 0.3 mm or more, even more preferably 0.5 mm or more, even more preferably 0.7 mm or more, and particularly preferably 0.8 mm or more. Also, from the viewpoint of further improving the strength of the semiconductor cleaning liquid pipe against a 60°C usage environment, the upper limit of the thickness range t1 of the first polyolefin resin layer is preferably 0.9 mm or less.

[0035] The ratio t1 [t1 / (t1+t2)] of the thickness of the first polyolefin resin layer to the sum of the thickness t1 of the first polyolefin resin layer and the thickness t2 of the second polyolefin resin layer is determined by the respective thicknesses t1 and t2, and from the viewpoint of further suppressing the amount of calcium and / or organic components eluted into the semiconductor cleaning liquid, the lower limit is, for example, 0.011 or more, preferably 0.013 or more, more preferably 0.04 or more, even more preferably 0.08 or more, even more preferably 0.12 or more, and particularly preferably 0.15 or more. The upper limit of the ratio is, for example, 0.17 or less, preferably 0.165 or less, and more preferably 0.16 or less, from the viewpoint of further improving the strength of the semiconductor cleaning liquid pipe against a 60°C usage environment.

[0036] Furthermore, it is more preferable that the thickness of the first polyolefin resin layer is adjusted so that the SDR (standard outer diameter / minimum wall thickness) is within a range of 7 to 17. An SDR of 7 or more is preferable because it is easy to ensure the transport amount of ultrapure water by ensuring a sufficient inner diameter relative to the outer diameter. Also, an SDR of 17 or less is preferable because it ensures the thickness of the second polyolefin resin layer, compensates for the lack of strength of the first polyolefin resin layer itself, and provides the semiconductor cleaning liquid piping as a whole with a more preferable strength suitable for practical use.

[0037] [3. Second polyolefin resin layer] The polyolefin resin used in the second polyolefin resin layer is not particularly limited, and can be appropriately selected from the polyolefin resins listed above as the polyolefin resins used in the first polyolefin resin layer. Among the above-mentioned polyolefin resins, high density polyethylene (HDPE) is preferred from the viewpoint of suppressing the elution of low molecular weight components and / or from the viewpoint of durability when pipes are washed with chemicals. The polyolefin resin used in the second polyolefin resin layer may be the same or different from the polyolefin resin used in the first polyolefin resin layer, but when both layers are laminated in contact with each other, it is more preferable that they are the same type of polyolefin resin from the viewpoint of improving the adhesion between the two layers and expressing a preferred strength.

[0038] The molecular weight of the polyolefin resin used in the second polyolefin resin layer is not particularly limited. From the viewpoint of strength, the molecular weight of the polyolefin resin used in the first polyolefin resin layer is preferably larger than that of the polyolefin resin used in the second polyolefin resin layer. For example, the weight average molecular weight Mw is preferably 5×10 5 ~8×10 5 , preferably 5.5 x 10 5 ~8×10 5 , more preferably 6 × 10 5 ~8×10 5 From the viewpoint of strength, the weight average molecular weight of the polyolefin resin used in the second polyolefin resin layer is 1.5 to 4 times, and preferably 2 to 4 times, the weight average molecular weight of the polyolefin resin used in the first polyolefin resin layer.

[0039] The molecular weight distribution (Mw / Mn) of the polyolefin resin used in the second polyolefin resin layer is not particularly limited, and may be 20 to 40. The molecular weight distribution (Mw / Mn) of the polyolefin resin used in the second polyolefin resin layer is preferably 20 or more, particularly when the weight average molecular weight of the polyolefin resin used in the second polyolefin resin layer is 1.5 to 4 times, preferably 2 to 4 times, the weight average molecular weight of the polyolefin resin used in the first polyolefin resin. In other words, the molecular weight distribution (Mw / Mn) of the polyolefin resin used in the second polyolefin resin layer is preferably 20 or more from the viewpoint of obtaining good strength by sufficiently securing low molecular weight components at the layer interface with the first polyolefin resin layer (i.e., by sufficiently securing the overlapping portion of the molecular weight distribution between both layers), thereby improving adhesion, and the molecular weight distribution of 40 or less is preferable from the viewpoint of obtaining the strength of the second polyolefin resin layer itself. In order to obtain these effects more satisfactorily, the molecular weight distribution (Mw / Mn) of the polyolefin resin used in the second polyolefin resin layer is preferably 22-30.

[0040] The amount of calcium elution from the material of the second polyolefin resin layer (polyolefin resin composition) measured in accordance with EMI F-57 is set to 30 μg / m from the viewpoint of ensuring the strength of the semiconductor cleaning solution pipe in a 60°C operating environment. 2 or more, preferably 50 μg / m 2 More preferably, 70 μg / m 2 More preferably, 80 μg / m 2 More preferably, 90 μg / m 2 More preferably, 95 μg / m 2 The above are some of the examples. The semiconductor cleaning liquid pipe of the present invention has an excellent effect of suppressing the elution of calcium and organic components, and therefore can effectively suppress the elution of calcium even if the material of the second polyolefin resin layer contains a large amount of calcium. From this viewpoint, a suitable example of the amount of calcium elution is 80 μg / m within the above range. 2 More than 90μg / m 2 or more than 95 μg / m 2 The upper limit of the amount of calcium elution is not particularly limited, but from the viewpoint of suppressing calcium elution, it is preferably 120 μg / m 2 Below, 110μg / m 2 or less than 100μg / m 2 The following are included:

[0041] The calcium concentration in the material (polyolefin resin composition) of the second polyolefin resin layer is not particularly limited as long as it satisfies the above calcium elution amount, but may be, for example, 20 ppm or more, preferably 30 ppm or more, more preferably 40 ppm or more, even more preferably 50 ppm or more, and even more preferably 60 ppm or more, from the viewpoint of ensuring the strength of the semiconductor cleaning liquid pipe in a usage environment of 60° C. The upper limit of the calcium concentration range may be, for example, 200 ppm or less, preferably 150 ppm or less, more preferably 130 ppm or less, and even more preferably 100 ppm or less, from the viewpoint of suppressing a lack of strength caused by the contained calcium itself becoming the starting point of fracture, and from the viewpoint of suppressing the elution of calcium and organic components.

[0042] The amount of organic components (TOC) eluted from the material (polyolefin resin composition) of the second polyolefin resin layer, as measured in accordance with EMI F-57, is, for example, 30,000 μg / m 2 The semiconductor cleaning liquid pipe of the present invention has an excellent effect of suppressing the elution of calcium and organic components, and therefore can effectively suppress the elution of organic components even if the material of the second polyolefin resin layer contains a large amount of organic components. From this viewpoint, a suitable example of the amount of eluted organic components is 31,000 μg / m 2 or more, preferably 31500 μg / m 2 The upper limit of the amount of eluted organic components is not particularly limited, but from the viewpoint of suppressing elution of organic components, it is preferably, for example, 35,000 μg / m 2 Less than or equal to 34000 μg / m 2 Less than or equal to 33,000 μg / m 2 More preferably, 32000 μg / m 2 The following are included:

[0043] The second polyolefin resin layer preferably contains an antioxidant. Examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, aromatic amine-based antioxidants, and lactone-based antioxidants. The content of the antioxidant in the second polyolefin resin layer is, for example, 0.01% by weight or more, preferably 0.1% by weight or more, from the viewpoint of suppressing the influence of oxygen and ensuring a preferable strength, and the upper limit of the content of the antioxidant is, for example, 5% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less.

[0044] [4. Gas barrier layer] When the semiconductor cleaning liquid pipe of the present invention has a gas barrier layer, the gas barrier layer is provided on the outside of the second polyolefin resin layer. The gas barrier layer prevents oxygen from the outer surface of the semiconductor cleaning liquid pipe from penetrating into the second polyolefin resin layer and further into the first polyolefin resin layer, thereby improving the strength of the semiconductor cleaning liquid pipe. In addition, providing a gas barrier layer is also preferable in that it can effectively suppress gas dissolution in ultrapure water.

[0045] Examples of materials for the gas barrier layer include polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride resin (PVDC), and polyacrylonitrile (PAN), and preferably polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

[0046] The thickness of the gas barrier layer is not particularly limited as long as it is a thickness that can ensure gas barrier properties to the extent that at least the strength reduction due to oxidative degradation of the polyolefin resin is suppressed, and examples of the thickness include 50 to 300 μm, preferably 100 to 250 μm, and more preferably 150 to 250 μm.

[0047] [5. Applications of semiconductor cleaning fluid piping] The semiconductor cleaning liquid piping of the present invention is used for transporting the semiconductor cleaning liquid. As the semiconductor cleaning liquid, ultrapure water refined to an extremely high purity and from which unnecessary substances have been strictly removed, or an ultra-high purity cleaning liquid from which unnecessary substances other than the necessary composition have been strictly removed, is used. In other words, in the present invention, the semiconductor cleaning liquid includes both ultrapure water and high purity cleaning liquid.

[0048] The semiconductor cleaning liquid piping of the present invention has excellent strength against an operating environment of 60° C., and therefore, when used to transport an ultra-high purity cleaning liquid, even when used to transport an ultra-high purity cleaning liquid obtained by diluting an undiluted cleaning liquid containing at least an amino compound (for example, an undiluted cleaning liquid containing an amino compound such as diaminoalkane, a chelating agent, a surfactant, and a pH adjuster) with ultra-pure water, it has excellent strength against an operating environment of 60° C. Note that, although a high purity cleaning liquid is itself composed of various organic components as exemplified above as necessary compositions, by transporting the high purity cleaning liquid using the semiconductor cleaning liquid piping of the present invention, which has excellent TOC elution suppression ability, contamination by unnecessary organic components derived from the piping material other than the necessary compositions can be suppressed.

[0049] The semiconductor cleaning liquid piping of the present invention can be used as piping in a semiconductor cleaning liquid production apparatus, piping for transporting a semiconductor cleaning liquid from a semiconductor cleaning liquid production apparatus to a use point, piping for returning a semiconductor cleaning liquid from a use point, etc. The semiconductor cleaning piping of the present invention may also be used as piping for transporting a semiconductor cleaning liquid after semiconductor cleaning for purification and reuse.

[0050] The semiconductor cleaning liquid pipe of the present invention is used in a wet cleaning process in the manufacturing process of semiconductor elements. The semiconductor elements are preferably those with a higher integration density, specifically, semiconductor elements with a minimum line width of 65 nm or less. Standards relating to the quality of semiconductor cleaning liquids used in semiconductor manufacturing include, for example, SEMI F75.

[0051] In addition, the semiconductor cleaning liquid pipe of the present invention is easy to join pipes to each other and has excellent workability. Furthermore, since both the line used for transporting ultrapure water and the line used for transporting ultrapure cleaning liquid can be made of polyolefin resin, the two lines can be easily joined to each other and has excellent workability. In joining the semiconductor cleaning liquid pipe of the present invention, for example, fusion construction such as butt fusion joining and EF (electrical fusion) joining can be easily performed at a relatively low temperature.

[0052] [6. Manufacturing of piping for semiconductor cleaning fluid] The semiconductor cleaning liquid pipe of the present invention can be manufactured by preparing a material for the first polyolefin resin layer, a material for the second polyolefin resin layer, and, if necessary, a material for the gas barrier layer, and co-extrusion molding the materials so that each layer has a predetermined thickness. Since the semiconductor cleaning liquid pipe of the present invention is made of polyolefin resin, it can be manufactured inexpensively.

[0053] The polyolefin resins constituting the first polyolefin resin layer and the second polyolefin resin layer can both be synthesized by polymerization using a chlorine-based catalyst such as the commonly used Ziegler-Natta catalyst (a catalyst made of triethylaluminum and titanium tetrachloride).

[0054] The amount of calcium and organic components eluted from each polyolefin resin layer is directly controlled by adjusting the amount of neutralizing agent added after polymerization. In addition, since the amount of neutralizing agent is affected by the amount of chlorine-based catalyst, the amount of calcium and organic components eluted can also be indirectly controlled by adjusting the amount of chlorine-based catalyst. In addition, the molecular weight distribution (Mw / Mn) in the polyolefin resin layer can be controlled by adjusting the amount of chlorine-based catalyst and / or the polymerization process (single-stage polymerization or multi-stage polymerization of two or more stages). For example, by increasing the amount of chlorine-based catalyst, the molecular weight distribution (Mw / Mn) tends to become larger. In addition, by performing multi-stage polymerization of two or more stages, the molecular weight distribution (Mw / Mn) can be increased.

[0055] More specifically, the polyolefin resin used in the first polyolefin resin layer can be prepared by, for example, polymerizing (e.g., one-stage polymerization) using a chlorine-based catalyst in an amount appropriately determined by a person skilled in the art, and then adding a predetermined amount of a neutralizing agent (e.g., calcium stearate, hydrocalcite, etc.) to a calcium concentration of 10 ppm or less. Alternatively, a neutralizing agent may not be added. The polyolefin resin used in the first polyolefin resin layer may also be polymerized using a polymerization catalyst other than the above chlorine-based catalyst, such as a chromium-based catalyst or a metallocene catalyst. In this case, it is not necessary to add a neutralizing agent.

[0056] The polyolefin resin used in the second polyolefin resin layer can be prepared by polymerizing (multi-stage polymerization, preferably two-stage polymerization) using a chlorine-based catalyst in an amount appropriately determined by a person skilled in the art, and then adding a predetermined amount (e.g., 20 to 200 ppm in terms of calcium concentration) of a neutralizer (e.g., calcium stearate, hydrocalcite, etc.), and preferably an antioxidant as well. EXAMPLES

[0057] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0058] (1) Preparation of piping for semiconductor cleaning solution Novatec HB534N (manufactured by Japan Polyethylene Co., Ltd.) was used as polyolefin (HDPE1) for the first polyolefin resin layer (first PO layer). Novatec HB534N is a completely additive-free high density polyethylene that does not contain any antioxidants. In addition, in the integral molecular weight distribution curve using standard polystyrene measured by gel permeation chromatography, the proportion of components with a molecular weight of 1000 or less was 0.75%. Furthermore, the calcium elution amount and organic component elution amount of the material for the first polyolefin resin layer (first PO layer) are as shown in Tables 1 and 2, respectively. Novatec HE222W (manufactured by Japan Polyethylene Co., Ltd.) was used as polyolefin (HDPE2) for the second polyolefin resin layer (second PO layer). Novatec HE222W is a PE100 grade high density polyethylene that contains an antioxidant. Furthermore, the amounts of calcium elution and organic components eluted from the material of the second polyolefin resin layer (first PO layer) are as shown in Tables 1 and 2, respectively.

[0059] Each resin composition was co-extrusion molded to have the thickness shown in Tables 1 and 2. Comparative Examples 1 and 2 were molded into single-layer pipes, and Examples 1 to 5 were molded into multi-layer pipes.

[0060] (2) Performance evaluation (2-1) Measurement of calcium elution amount and organic matter (TOC) elution amount The obtained semiconductor cleaning solution pipe was cut to a length of 200 mm, ultrapure water was sealed inside, both ends were plugged with polytetrafluoroethylene (PTFE), and the pipe was fixed from the outside with wire to obtain a test sample. The ultrapure water used was one in which the calcium concentration and TOC amount were below the detection limit of the measuring device (the ISP-MS device and TOC meter described below). The test sample was left to stand for 7 days under the condition of 85°C ± 5°C to perform dissolution. After dissolution, the amount of calcium and TOC in the water in the test sample were measured using an ISP-MS device (Agilent Technologies, model number Agilent7500cs) and a TOC meter (Thermo Fisher Scientific, model number ICS2000), respectively. The standard value that must be met for the amount of calcium dissolution is 30 μg / m 2 based on the SEMI F57 standard. 2 The TOC elution standard is 30,000 μg / m 2 The results are shown in Tables 1 and 2.

[0061] (3-2) Strength (internal pressure creep performance) measurement A semiconductor cleaning solution pipe with an outer diameter of 60 mm was prepared, cut to a length of 300 mm, and both ends were sealed with metal fixtures to obtain a test sample. According to the internal pressure creep test method described in JIS K6761, the pipe was subjected to conditions of 60°C and 1 MPa for 165 hours, and it was checked whether or not it broke. If it broke, it was evaluated as ×, and if it did not break, it was evaluated as ○. The results are shown in Tables 1 and 2.

[0062] [Table 1]

[0063] [Table 2]

[0064] As shown in the table above, the calcium elution amount is 30 μg / m 2 In the case of the pipe made of a material less than 1000 g / m2 (Comparative Example 1), the amount of calcium elution and TOC elution in ultrapure water was small, but the strength in a 60°C environment was not obtained, and the amount of calcium elution was 30 μg / m2.2 The pipe made of the above materials (Comparative Example 2) had sufficient strength in a 60°C environment, but had excessive calcium elution into ultrapure water and could not meet the quality requirements for semiconductor cleaning fluids. The TOC elution amount also did not meet the standards of this test. Calcium elution amount: 30 μg / m 2 The inner layer is made of materials with a calcium elution rate of 30 μg / m 2 In the case of a multi-layer pipe composed of an outer layer made of the above materials, when the thickness of the inner layer was more than 0.95 mm (Comparative Example 1), a significant decrease in the amount of calcium elution was observed, probably due to the calcium in the inner layer migrating to the outer layer side as a result of the stacking of the outer layers, resulting in a calcium gradient in the thickness direction, while the internal pressure creep measurement showed destruction in 133 hours, and strength in an environment of 60°C was not obtained. Also, when the thickness of the inner layer was less than 0.06 mm (Comparative Example 2), although strength in an environment of 60°C was obtained, calcium in the outer layer migrated to the inner layer side due to the stacking of the outer layer and was excessively eluted into the ultrapure water, failing to meet the quality requirements for semiconductor cleaning fluid, and the amount of TOC elution did not meet the standards of this test.

[0065] In contrast, when the thickness of the inner layer is 0.06 to 0.95 mm (Examples 1 to 5), not only is the amount of calcium elution suppressed to a level that satisfies the required quality of the semiconductor cleaning liquid, but a decrease in the amount of calcium elution is observed, probably due to the migration of calcium in the inner layer to the outer layer side as a result of the lamination of the outer layer, which creates a calcium gradient in the thickness direction, and strength is also obtained in a 60°C environment. In addition, a decrease in the amount of TOC elution is also observed. In view of these levels of calcium and TOC elution, it is recognized that the semiconductor cleaning liquid pipes of Examples 1 to 5 are suitable for transporting semiconductor cleaning liquid suitable for wet processing of semiconductor elements with a minimum line width of 65 nm or less. [Explanation of symbols]

[0066] 100, 100a, 100b Semiconductor cleaning solution piping 210, 210a First polyolefin resin layer 220 Second polyolefin resin layer 300 Gas barrier layer t1 Thickness of the first polyolefin resin layer t2 Thickness of the second polyolefin resin layer

Claims

1. The present invention includes a first polyolefin resin layer constituting an innermost layer, and a second polyolefin resin layer disposed on an outer side of the first polyolefin resin layer, The amount of calcium elution of the first polyolefin resin layer measured in accordance with SEMI F-57 is 30 μg / m 2 is less than The first polyolefin resin layer has a thickness of 0.1 to 0.95 mm, the polyolefin resin in the second polyolefin resin layer is high-density polyethylene and / or polypropylene; the amount of calcium elution from the second polyolefin resin layer is 95 μg / m 2 or more as measured in accordance with SEMI F-57; A pipe for a semiconductor cleaning liquid, wherein a ratio of a thickness of the first polyolefin resin layer to a total thickness of the first polyolefin resin layer and the second polyolefin resin layer is 0.013 to 0.

155.

2. 2. The semiconductor cleaning liquid pipe according to claim 1, wherein in an integrated molecular weight distribution curve of the first polyolefin resin layer measured by gel permeation chromatography, a proportion of components having a molecular weight of 1000 or less is 0.15% or more.

3. 3. The semiconductor cleaning liquid pipe according to claim 1, further comprising a gas barrier layer on the outside of the second polyolefin resin layer.

4. 4. The semiconductor cleaning liquid piping according to claim 1, wherein the semiconductor cleaning liquid is used in a wet processing step of a semiconductor element having a minimum line width of 65 nm or less.

5. The present invention includes a first polyolefin resin layer constituting an innermost layer, and a second polyolefin resin layer disposed on an outer side of the first polyolefin resin layer, The amount of calcium elution of the first polyolefin resin layer measured in accordance with SEMI F-57 is 30 μg / m 2 is less than The first polyolefin resin layer has a thickness of 0.1 to 0.95 mm, the polyolefin resin in the second polyolefin resin layer is high-density polyethylene and / or polypropylene; the amount of calcium elution from the second polyolefin resin layer is 95 μg / m 2 or more as measured in accordance with SEMI F-57; A multi-layer pipe, wherein a ratio of a thickness of the first polyolefin resin layer to a total thickness of the first polyolefin resin layer and the second polyolefin resin layer is 0.013 to 0.155.

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