JPH10291520A - Chemical liquid container - Google Patents

Abstract

(57) [Problem] To provide a fluororesin container suitable as a chemical liquid container for semiconductor production. SOLUTION: The container wall is composed of a single layer of PFA or FEP in which the unstable group at the molecular terminal is stabilized, or a multilayer having the terminal stabilized PFA or FEP layer as the innermost layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorochemical liquid container suitable for storing and transporting a high-purity liquid chemical. In particular, the present invention relates to a chemical solution container which is suitable for storing and transporting a chemical solution used for manufacturing a semiconductor and which can be increased in size.

[0002]

2. Description of the Related Art Fluororesins are excellent in chemical resistance and have been used as chemical containers for storing and transporting various chemicals.

Among these, chemicals used for semiconductor production, such as surfactants, strong acids (such as hydrofluoric acid), and strong alkalis, are required to be highly purified with the increasing integration of devices. There is a demand for minimizing contamination (mixing of anions, metal impurities, fine particles, etc.) in the manufacturing process as much as possible. For example, the permissible mixing unit of metal impurities has become stricter from ppb to ppt, and the permissible particle diameter of fine particles has become stricter from 0.2 μm to 0.1 μm, and the demand for higher purity is expected to be further increased.

[0004] However, no matter how high the purity of the chemical solution during the manufacturing process, if the produced chemical solution is contaminated while being stored and transported in a container, it is all useless.

The following requirements are required for such a chemical solution container for semiconductor production.

(1) Material side: It has a broad chemical resistance to various chemicals such as strong acids, strong alkalis and surfactants, and does not deteriorate with time.

[0007] (Metal) impurities and anions should not be eluted from the container itself.

(2) Manufacturing aspect: No contaminants adhere at the manufacturing stage.

(3) Shape surface: The inner surface of the container is smooth and fine particles and the like do not adhere.

[0010] In response to such demands, at present, from the viewpoint of material, fluororesins (PFA, FEP, ETFE, EPE, etc.)
And polyethylene are used. In terms of production, blow molding and rotational molding (roto molding)
Method and welding lining method are adopted.

[0011] Polyethylene chemical solution containers are most widely used in terms of price, ease of molding, etc., but are poor in environmental resistance (for example, poor in chemical resistance to some chemicals such as surfactants). Point, inferior weather resistance, deterioration with time, environmental stress cracking, etc.), silica (Si) elution caused by the catalyst used in the production of polyethylene, and prevention of the deterioration with time. Problems have been pointed out, such as dissolution of additives to be blended.

To solve these problems, PFA,
A chemical container made of a fluororesin such as FEP, ETFE, and EPE has also been proposed. When using fluororesin,
Certainly, the chemical resistance and the deterioration over time are improved, but problems such as generation of fluorine ions due to decomposition of the resin during molding and elution of fluorine ions into the chemical solution remain.

[0013] Fluororesins, especially melt-moldable fluororesins, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (PFA) and tetrafluoroethylene / hexafluoropropylene copolymer (F
EP) and the like is, -CH ₂ OH derived from the polymerization initiator used in the polymerization (APS, -COOH or molecular weight modifier derived from KPS etc.) (lower alcohol)
And terminal groups such as —COOCH ₃ remain.

These terminal groups are thermally unstable and thermally decompose during melt molding to form --COF. Furthermore, this-
COF is also hydrolyzed and causes elution of fluorine ions and the like.

[0015]

DISCLOSURE OF THE INVENTION The present invention relates to a chemical solution container which is excellent in chemical resistance to various chemical solutions, does not deteriorate with time, suppresses elution of impurities, and can achieve a high degree of smoothness of the inner surface. The purpose is to provide.

[0016]

That is, the present invention relates to a chemical solution container comprising a single layer of PFA or FEP in which unstable groups at the molecular terminals are stabilized.

The present invention also relates to a chemical solution container having a multi-layered container wall having the PFA or FEP layer as the innermost layer.

These chemical containers are most suitable as containers for storing and transporting chemicals for manufacturing semiconductors.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) One embodiment of the drug solution container of the present invention is a container having a single layer of terminal-stabilized PFA or FEP as a container wall.

PFA or FEP used in the present invention is tetrafluoroethylene (TFE) and a compound represented by the formula (I): CF ₂ ＣＦCF—R _f (I) (where R _f is —OR ¹ _f (R ¹ _f is a copolymer of a monomer represented by a perfluoroalkyl group) or -CF ₃₎ of 1 to 5 carbon atoms, in which labile groups at the molecular ends is stabilized. When R _f of the monomer of the formula (I) is —OR _f ¹ , that is, perfluoro (alkyl vinyl ether)
Is PFA, and R _f is —CF ₃
, Ie, hexafluoropropylene (HFP)
The obtained copolymer is FEP. In the case of PFA, the molar ratio of TFE / perfluoro (alkyl vinyl ether) is 99.7 / 0.3 to 85/15, preferably 99/1 to 95/5, and in the case of FEP,
/ HFP is 99.7 / 0.3 to 85/15, preferably 95/5 to 90/10, in a molar ratio.

Of these, PFA is preferred from the viewpoint of environmental resistance (particularly mechanical strength).

As described above, PFA or FEP has --COF, --COOH, --CH ₂ OH, --C
Although unavoidably has an unstable group such as OOCH ₃ ,
These unstable groups are fluorinated, and if necessary, treated with ammonia gas or the like to obtain -CF ₃ , -CON
By converting to a stable group such as H ₂ , the terminal stabilized PFA or FEP used in the present invention can be obtained. As a method for stabilizing the terminal, for example, JP-A-60-240713,
JP-A-61-98709, JP-A-62-104822
JP-A-3-250008, JP-A-4-20507
JP-A-6-128335, JP-A-8-28333
A known method described in Japanese Patent Publication No. 8 and the like can be employed. For example, there is a method in which PFA or FEP is brought into contact with fluorine gas and then brought into contact with ammonia gas again to convert the terminal unstable group into stable -CONH ₂ (JP-A-4-20507).

The terminally stabilized PFA or FEP is
Usually, the number of carbon atoms of the resin 10 ⁶ per -COF and -COO
H and the -CH ₂ OH sum of them 50 or less, preferably only contains 30 or less.

Such terminal-stabilized PFA or FEP can be melt-molded, and can be formed into a predetermined chemical solution container by a blow molding method, a rotational molding method, a welding lining method, or the like.

When the container of the present invention is used particularly as a chemical liquid container for manufacturing semiconductors, the blow molding method among the above molding methods is advantageous in that a smooth inner surface is easily obtained and the molding cost is low. Is advantageous. A conventional blow molding method can be adopted as the blow molding method.

Incidentally, other molding methods, for example, a rotational molding method,
The conventional method may be used for the welding lining method and the like.

Next, the shape and dimensions of the chemical solution container according to the first embodiment will be described.

The shape is generally spherical or cylindrical, but is not limited to these.

As for the dimensions, those for 0.1 to 1000 liters can be usually manufactured, and the thickness of the container wall is about 0.1 to 5 liters.
mm, preferably about 1 to 3 mm.

The chemical container of the present invention can be used for various chemical solutions. Typical chemicals include, for example, sulfuric acid, hydrochloric acid, aqueous ammonia, aqueous hydrogen peroxide, hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid containing a surfactant, phosphoric acid, nitric acid, acetic acid, isopropyl alcohol for semiconductor production. N-butyl acetate, monoethanolamine and the like. In addition, it is also useful as a container for storing and transporting pharmaceutical intermediates and blood.

The chemical solution container of the present invention thus manufactured can be used as it is as various types of chemical solution containers.
For example, when used as a chemical solution container for semiconductor production, in many cases, it is used in another outer container called a container. The container is intended to reinforce or transport the internal container, and is known to be made of metal, FRP, polypropylene, or the like.

(Embodiment 2) In Embodiment 2 of the present invention, the container wall of the chemical solution container is multi-layered into two or more layers, and the innermost layer is the terminal-stabilized PFA or F
The present invention relates to a drug solution container manufactured by EP.

The terminal-stabilized PFA or FEP used in this embodiment is the same as in the first embodiment.

The material of the layers other than the innermost layer may be the same as or different from the material of the innermost layer. Examples of different kinds of materials include PFA and FEP before terminal stabilization; resins reinforced by blending them with fillers; P having reactive groups;
FA and FEP; other known fluororesins such as ETFE, ECTFE, and PVdF; FRP; Particularly in blow molding, it is more economically advantageous if the upper and lower loss portions of the parison are re-ground and used as the material of the outer layer.

The multilayer structure has a PF in which the innermost layer is terminal-stabilized.
If it is A or FEP, it may have a structure of two or three or more layers. From the inner surface side, preferred layer structures include terminal-stabilized PFA / non-terminal-stabilized PFA, terminal-stabilized PFA / non-terminal-stabilized FEP, terminal-stabilized PFA / ETFE, terminal-stabilized PFA / PVdF, Examples include a two-layer structure such as terminal-stabilized PFA / ECTFE, but are not limited thereto.

As the molding method, the same molding method as in the first embodiment can be adopted. For example, in order to form a multilayer structure by a blow molding method, a parison may be extruded by a co-extrusion method and blow molding may be performed.

The shape of the container in the second embodiment is the same as that in the first embodiment. Regarding the dimensions, since the strength and durability of the entire container are improved by forming a multilayer structure, it is possible to further increase the size and reduce the thickness of the innermost layer. In the case of multiple layers, the thickness of the container wall is about 0.1 to 10 mm in total, usually 1
About 5 mm. Especially the innermost layer of PFA or FEP
The thickness of the layer is about 0.05 to 2 mm, preferably about 0.1 to 2 mm.
The thickness can be reduced to 1 mm, and cost reduction and weight reduction can be achieved.

The chemical solution container of the second embodiment is also the same as that of the first embodiment.
It is suitable for use as a chemical liquid container for semiconductor production.

[0039]

According to the chemical solution container of the present invention (Embodiment 1), it has excellent chemical resistance to strong acids, strong alkalis, various surfactants, etc., less elution of impurities such as metals and fluorine ions, and weather resistance. It has excellent resistance to environmental degradation, has little deterioration over time, can be used for a long time, has a highly smooth inner surface of the container, has no adhesion or residue of fine particles (especially blow molding), and is easy to mold at low cost. There is an advantage that it can be manufactured (especially blow molding). According to the second embodiment, in addition to these advantages, mechanical strength is large, durability is improved, weight can be reduced, and relatively expensive. Advantages such as a reduction in the amount of PFA and FEP used and a reduction in the cost of the container can be achieved.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasuyuki Yamaguchi 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yodogawa Works (72) Inventor Ken Ken Okanishi 1-1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries (72) Inventor Minoru Yoshida 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd.

Claims (3)

[Claims] 1. A chemical container comprising a single layer of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer or a tetrafluoroethylene / hexafluoropropylene copolymer in which an unstable group at a molecular end is stabilized. 2. A multilayer having a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer layer or a tetrafluoroethylene / hexafluoropropylene copolymer layer in which an unstable group at a molecular terminal is stabilized as an innermost layer. Liquid container having a closed container wall. 3. The chemical solution container according to claim 1, which is used as a container for a chemical solution for semiconductor production.