KR102489717B1 - Container for storing high-purity hydrogen fluoride using a metal substrate having low corrosion resistance, and a method for manufacturing the same - Google Patents

Abstract

The present invention relates to a container for storing high-purity hydrogen fluoride, using an inexpensive metal substrate such as carbon steel, adjusting the surface roughness R _a of the substrate to 0.5 μm or less, and then plating the surface with nickel. It relates to a container for storing high-purity hydrogen fluoride, which is made to have sufficient corrosion resistance by increasing the density of a plating film.

Description

Container for storing high-purity hydrogen fluoride using a metal substrate having low corrosion resistance, and a method for manufacturing the same}

The present invention relates to a container for storing high-purity hydrogen fluoride, wherein a metal substrate having weak corrosion resistance is used, and a nickel plating film is formed after adjusting the surface roughness of the low corrosion resistance metal, thereby forming a nickel plating film and a fluoride passivation film. It relates to a container for storing high-purity hydrogen fluoride, which further improves efficiency and corrosion resistance so that hydrogen fluoride, a corrosive gas, can be stored and transported in high purity.

In the manufacturing process of semiconductor devices, MEMS (Micro Electro Mechanical Systems) devices, liquid crystal TFT (Thin Film Transistor) panels, and solar cell panels, nearly 150 types of gases are used depending on process characteristics such as etching process, film formation process, and cleaning process. It is being used.

For example, in the semiconductor manufacturing process, hydrogen chloride (HCl), boron trichloride (BCl ₃ ), fluorine (F ₂ ), nitrogen trifluoride (NF ₃ ), chlorine trifluoride (ClF ₃ ), hydrogen bromide (HBr), hydrogen fluoride Halogen-based special gases with high reactivity and corrosiveness, such as (HF), are used. In particular, in etching gas and cleaning processes, hydrogen fluoride (HF) is used as a highly active corrosive gas, and the hydrogen fluoride is Ultra-high purity is required to minimize the defect rate due to the increasingly increasing nature of the semiconductor process.

However, hydrogen fluoride is a highly active corrosive gas, which is easily hydrolyzed by moisture in the air and very easily corrodes metal materials or metal film structures constituting storage containers, valves, pipes, reaction chambers, etc. that handle hydrogen fluoride. As a result, it is very difficult to store it in high purity without contamination due to corrosion.

In particular, substances such as impurities H ₂ and CH ₄ are formed by reacting with HF even in a container made of SUS316L, which has strong corrosion resistance, and the impurities increase over time. Manufacturing of semiconductor devices with gas containing the generated impurities In order to solve this problem, it is necessary to use a material with strong corrosion resistance because it adversely affects the semiconductor device. In order to solve this problem, as an alloy and metal film with excellent corrosion resistance that can handle hydrogen fluoride, Japanese Patent Registration No. 3891815 (2006.12.15) is an alloy with excellent corrosion resistance, containing 4.0 to 5.0 mass% of Mg and 0.02 to 0.1 mass% of Cr, and each content of Si, Fe, Cu, Mn, Zn, and Ni as impurities is 0.1 mass%, respectively. An aluminum alloy for film forming treatment, which is regulated below and the balance is composed of Al and other impurities, is known, and it is disclosed that the alloy and alloy material are suitable as materials for semiconductor manufacturing equipment. However, in the case of the prior literature, there is a problem in that it is difficult to maintain corrosion resistance when limited to aluminum alloys, manufacturing and refining processes to have such a composition are complex, and scratches are formed by external stimuli.

Therefore, in general, by plating a metal substrate with a metal having corrosion resistance or by fluorination to passivate the fluoride, it is being developed to exhibit very high corrosion resistance to corrosive gases.

Since the passivation layer using such fluorine gas is not thick and is vulnerable to scratches, Korean Patent Registration No. 10-0308688 (November 30, 2001) discloses a metal made of nickel or nickel alloy to form a thick passivation layer. After forcibly oxidizing the surface of a material or nickel or nickel alloy film, passivating the forced oxidized layer using fluorine or the like to form a fluoride layer of 1 μm or more on the surface to improve corrosion resistance has been disclosed. However, in the case of the prior literature, the surface of the nickel or nickel alloy film is forcibly oxidized, and the fluoride layer must also be formed to a considerable thickness of 1 μm or more, so the process is complex, as well as the relationship between the fluoride layer and the base material. Adhesion is reduced, and it is unreasonable to improve wear resistance and durability to a satisfactory level with a fluorinated layer and maintain it for a considerable period of time.

In addition, Hastelloy, which is a nickel-based alloy with very strong corrosion resistance, and Inconel, which has nickel as the main component and 15% of chromium, has excellent heat resistance and corrosion resistance, are considered as device materials for handling hydrogen fluoride. However, in the case of these alloys, they are expensive and have poor processability, which reduces economic feasibility and process efficiency. It is being developed to express high corrosion resistance.

Therefore, the present invention was conceived to solve the above problems, and when the surface roughness of the metal substrate is adjusted within a certain range, the corrosion resistance of the metal substrate itself and the adhesion to the coating film formed on the substrate and the density of the coating film are improved. It was found that it exhibits corrosion resistance even against strong acids such as hydrogen fluoride, and the present invention was completed.

According to the present invention, low corrosion resistance materials such as carbon steel, which easily react with oxygen and corrode, can also be applied as metal substrates for storage containers of high-purity fluorine gas, especially high-purity hydrogen fluoride for semiconductors, thereby improving economic feasibility.

Japanese Patent Registration No. 3891815 (2006.12.15) Korean Patent Registration No. 10-0308688 (2001.11.30)

An object of the present invention is to provide a storage container for storing high-purity hydrogen fluoride using a low-cost, low-corrosion-resistant carbon steel-based metal.

In addition, the present invention has another problem to provide a method for manufacturing a container for storing high-purity hydrogen fluoride using a low-cost, low-corrosion-resistant metal such as carbon steel.

In order to solve the above problems, the present invention is a container for storing high-purity fluorine gas, the container includes a material in which a nickel plating film is plated on the surface of a metal substrate, the nickel plating film is used as the inner surface of the container, The metal substrate provides a storage container for storing high-purity hydrogen fluoride, characterized in that the center line average roughness (R _a ) is 0.5 μm or less in surface roughness.

In one embodiment of the present invention, the metal substrate may be carbon steel, and a fluoride passivation film may be formed on the surface of the nickel plating film.

In one embodiment of the present invention, the thickness of the fluorinated passivation film is characterized in that 0.1 ~ 1 ㎛.

In addition, the present invention is a method for manufacturing a container for storing high-purity fluorinated gas, (1) a metal substrate constituting the inner surface of the storage container is prepared so that the center line average roughness (R _a ) of the surface of the metal substrate is 0.5 μm or less polishing; (2) plating nickel on the polished metal substrate to form a nickel plating film; it provides a method for manufacturing a container for storing high-purity hydrogen fluoride, characterized in that it includes.

In one embodiment of the present invention, the metal substrate in step (1) may be carbon steel, and after step (2), (3) further comprising the step of forming a fluoride passivation film by fluorination treatment of the nickel plating film. can do.

In one embodiment of the present invention, in the step of forming a fluorinated passivation film of (3), prior to fluorinating the nickel plating film, a step of oxidizing the nickel plating film may be further included.

The present invention uses an inexpensive metal as a metal substrate for a high-purity hydrogen fluoride storage container, but also improves the corrosion resistance of the substrate itself by adjusting the surface roughness of the metal substrate, as well as the nickel plating film formed on the metal substrate. As the coating film stability and density are improved, carbon steel with strong corrosiveness can also be applied as a metal substrate, and thus, economic feasibility and strength stability can be improved.

In addition, the present invention improves the corrosion resistance to hydrogen fluoride of the inner surface of the storage container by improving the adhesion and density of the fluoride passivation film as well as the nickel plating film by adjusting the surface roughness of the metal substrate.

In addition, according to the present invention, not only the inner surface of the container but also the connected valves are treated with fluoride passivation by removing a chemical substance having a fluoride group inside the container through a valve mounted on the container after being aged for a certain period of time after filling the container. By improving the corrosion resistance, it is possible to maintain high purity of the high-purity hydrogen fluoride stored inside the container.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is one well known and commonly used in the art.

When it is said that a certain part "includes" a certain component throughout this specification, it means that it may further include other components, not excluding other components unless otherwise stated.

Hereinafter, the present invention will be described in detail.

High integration is progressing in the field of semiconductor and liquid crystal manufacturing, and ultra-fine pattern processing of 1 μm or less is required. In this ultra-LSI manufacturing process, a large amount of gas is used for microfabrication on a Si wafer, such as film formation and etching, and recently, the amount of fluorinated gas used as an etching and cleaning gas has increased. In the semiconductor manufacturing process, even if minute dust or a small amount of impurity gas adheres to or adsorbs on the wiring pattern, it can cause a circuit defect. As a highly corrosive gas, it is easily hydrolyzed by moisture present in the atmosphere to generate hydrofluoric acid, etc., and metal materials or metal film structures constituting valves, pipes, storage containers, etc. that handle this gas are very easily corroded. It becomes difficult to maintain high purity.

Therefore, Hastelloy as a nickel alloy, which is a corrosion-resistant metal that is resistant to corrosive gases such as hydrogen fluoride, and Inconel, which has excellent heat resistance and corrosion resistance, are used as a main component of nickel and 15% of chromium is added. , Since the metal is expensive, it is difficult to meet the economic feasibility, and therefore, it is necessary to develop a technology capable of using low-cost metals such as carbon steel.

Accordingly, the present invention is a container for storing high-purity fluorinated gas, wherein the container includes a material in which a nickel plating film is plated on the surface of a metal substrate, the nickel plating film is used as the inner surface of the container, and the metal substrate has a surface roughness Provides a storage container for storing high-purity hydrogen fluoride, characterized in that the center line average roughness (R _a ) is 0.5 μm or less.

In the present invention, the metal substrate is not particularly limited as long as it has stability and compactness usable as a container, but is preferably selected from carbon steel, aluminum, aluminum alloy, nickel, nickel alloy, copper, copper alloy, chromium and stainless steel. It may be any one, more preferably carbon steel, and the thickness of the metal substrate is in a range that meets gas stability standards.

Carbon steel is an alloy steel of iron and carbon that contains 0.02 to 2.1% of carbon and may contain silicon, manganese, phosphorus, sulfur, etc. as impurities. When used as a substrate, the strength and economic efficiency of the container can be improved, but it is difficult to use it as a container for strong acids such as hydrogen fluoride as it easily reacts with oxygen and corrodes.

However, the container material of the present invention includes a nickel plating film and a passivated fluoride film having excellent acid resistance formed on the top of the metal substrate together with a metal substrate, and significantly improves corrosion resistance by adjusting the surface roughness of the metal substrate within a certain range. , Even if the metal substrate is easily corroded carbon steel, it can have corrosion resistance, especially corrosion resistance to hydrogen fluoride, so that inexpensive metal can be used as a material for a storage container of high purity hydrogen fluoride, thereby improving both economic efficiency, strength and corrosion resistance. can

The metal substrate of the present invention has a center line average roughness (R _a ) of 0.5 μm or less in surface roughness.

Surface roughness refers to the degree of fine irregularities that occur on the surface when the metal surface is trimmed. It can be defined by maximum height (R _max ), ten point average roughness (R _z ) and center line average roughness (R _a ), and affects the physical and chemical properties of the contact part.

When the R _a of the metal substrate exceeds 0.5 μm, the surface of the metal substrate is easily On the other hand, when R _a of the metal substrate is 0.5 μm or less, the contact area of the metal substrate is minimized, which may exist on the surface of the metal substrate due to oxygen in the air, moisture, etc. - OH and oxygen are minimized, and furthermore, generation of H ₂ and CH ₄ by the reaction between OH and HF is suppressed. That is, the metal substrate with R _a adjusted to 0.5 μm or less has reduced contact and reactivity with oxygen, moisture and corrosive substances in the atmosphere by minimizing the contact area with the reactant, thereby suppressing the generation of impurities due to the reaction, It can maintain the purity of my hydrogen fluoride gas.

In addition, when nickel plating is performed on a metal substrate where R _a is adjusted to 0.5 μm or less, particles generated during the nickel plating process, which occur when nickel plating is performed on a metal substrate where R _a is not adjusted, are inside the container. There is no residual problem in

When the Ra of the inner surface of the container is more than 0.5 ㎛ and the surface roughness is poor, the amount of metal material eluted during nickel plating is relatively large, and the material of the eluted metal remains on the surface of the plating layer and remains as metal particles and reacts with hydrogen fluoride This adversely affects the generation of metal ions in hydrogen fluoride and the maintenance of high purity of hydrogen fluoride. Therefore, it is important to maintain the surface roughness of the metal substrate to 0.5 μm or less during plating.

In addition, when plating is performed on a metal substrate in which R _a is adjusted to 0.5 μm or less, the surface roughness of the plated film after nickel plating is improved, so that a sufficiently uniform nickel plated film is formed even without making the nickel plated film thick. When the plating film is treated with fluoride, a more stable fluoride passivation film containing nickel fluoride is formed, and the formed fluoride passivation film also has density, thereby improving corrosion resistance and high purity hydrogen fluoride due to contamination It can be stored without loss of purity.

The fluorinated passivation film may be formed by fluorination treatment using fluorinated gas, and the fluorinated gas used is fluorine (F ₂ ), hydrogen fluoride (HF), chlorine trifluoride (ClF ₃ ) and nitrogen fluoride (NF ₃ ), methane fluoride At least one type of gas selected from the group consisting of (CH ₃ F) or a gas obtained by diluting this gas with an inert gas is exemplified.

Chlorine trifluoride is thermally decomposed at 60 ~ 100 ℃ to generate fluorine radicals, which can be used for fluorination reactions. In addition, nitrogen fluoride is decomposed by plasma energy to generate fluorine radicals, which can be used for fluorination reactions. As the dilution gas, an inert gas such as nitrogen or helium can be used, and nitrogen is preferable. When the fluorinated gas is diluted and used, its concentration can be appropriately set depending on the reaction conditions. For example, in the case of fluorine, it is preferable to use it at a concentration of about 10% in consideration of cost and the like.

During the fluorination treatment, the temperature is 200 to 500°C, preferably 200 to 390°C, and more preferably 250 to 380°C. In addition, the time of fluorination treatment is 1 to 12 hours. After the fluorination treatment, heat treatment may be performed at a temperature of 100 to 300°C, preferably 150 to 200°C. This heat treatment is performed for 1 to 12 hours in an inert gas such as N ₂ , Ar, He, etc., so that a strong and dense fluorinated passivation film can be formed on the substrate.

In order to form _a fluorinated film through fluorination treatment of the nickel plated film, the fluoride treatment may be performed immediately after the plating film is formed without any pretreatment. may be enforced. By doing this, it is possible to improve the long-term durability of the fluoride passivation film by bringing the density and thickness of the fluoride passivation film produced by the fluoride treatment.

In the present invention, the surface roughness value R _a of the metal substrate may be in the range of 0.5 μm or less, preferably 0.2 μm or less. The lower limit of R _a is not necessarily limited, but may be 0.1 μm. This is because if the thickness is less than 0.1 μm, the effectiveness of the effect of improving corrosion resistance may decrease compared to the effort required for the process for reducing surface roughness.

The surface roughness of the metal substrate may be achieved by mechanical polishing or electrical polishing. Physical polishing is commonly referred to as buffing, which means making a smooth surface by rubbing with an abrasive, and chemical polishing means a process called electrolytic polishing, which is generally 55 to 75 ° C. of phosphoric acid and sulfuric acid. A current of 12 to 15 V is applied to the polishing method.

In the present invention, both physical and chemical polishing methods can be used to control the surface roughness of the metal substrate, but in order to form R _a of the metal substrate to 0.5 μm or less, it is physically or chemically polished, but the polishing time is 5 to 24 hours . If the polishing time is less than 5 hours, the polishing is not sufficiently performed so that the Ra of the metal substrate cannot be formed below 0.5 ㎛, and if the polishing time exceeds 24 hours, the degree of change in Ra according to the polishing time is reduced, reducing process efficiency or Alternatively, damage such as cracks or pinholes may occur on the surface of the metal substrate due to excessive polishing, which may reduce corrosion resistance.

In addition, when a metal substrate is polished by a physical polishing method, an abrasive having a particle size of 4 a.u or less is used. This is because the smoothness of the metal substrate is reduced and the surface roughness is increased when the abrasive particle size exceeds 4 a.u.

In the present invention, the nickel plating film is formed on a metal substrate having _a surface center line average roughness, Ra, of 0.5 μm or less as described above.

At this time, the nickel plated film is formed with a high Ni content of 85% or more and has a thickness of 5 to 60 μm, preferably 30 to 40 μm, on the surface of the metal substrate. When the thickness of the nickel plating film is less than 5 μm, corrosion resistance is reduced because a sufficient nickel plating film cannot be formed on the surface of the metal substrate, and when the thickness exceeds 60 μm, the nickel plating film is excessively thick. Although the adhesion with the nickel coating film is improved by adjusting R _a to 0.5 μm or less, the bonding stability between the nickel plating film and the substrate may rather deteriorate.

In the present invention, the passivated fluoride film is formed to a thickness of 0.1 to 1 μm by fluorination treatment on the nickel plated film, preferably the oxidized nickel plated film. The fluoride passivation film may be formed by fluorination treatment of the nickel plating film, but may be formed as a fluoride passivation film having enhanced acid resistance than when formed by fluorination treatment of the oxidized nickel plating film.

As described above, the container material of the present invention can improve the corrosion resistance of the metal substrate itself by adjusting the surface roughness of the metal substrate, as well as solve the problem that particles generated in the plating process remain inside the container, and can provide a uniform By forming a nickel plating film with a thickness, it is possible to maintain the roughness quality of the surface after plating.

The present invention, (1) polishing the metal substrate so that the center line average roughness (R _a ) of the surface of the metal substrate constituting the inner surface of the storage container is 0.5 ㎛ or less; and (2) plating nickel on the polished metal substrate to form a nickel plating film.

The present invention also provides a container material manufacturing method for storing high-purity hydrogen fluoride, further comprising: (3) forming a fluoride passivation film by fluorination treatment of the nickel plating film after the step (2). A step of adjusting R _a to 0.5 μm or less by re-polishing the surface of the nickel plated film plated on the metal substrate polished in step (2) before the step (3) may be further included.

First, in the present invention, (1) polishing the metal substrate is a step of polishing the metal substrate so that the center line average roughness (R _a ) of the surface of the metal substrate is 0.5 μm or less according to KS B 0161, physical polishing ( Mechanical polishing) or chemical polishing (Electrical polishing), and the polishing time is 5 to 10 hours. If the polishing time is less than 5 hours, the polishing is not sufficiently performed, so that the R _a of the metal substrate cannot be formed to less than 0.5 ㎛, and if the polishing time exceeds 10 hours, the degree of change in R _a according to the polishing time is reduced, resulting in an increase in process efficiency. This is because damage such as cracks or pinholes may occur on the surface of the metal substrate due to reduced or excessive polishing, thereby reducing corrosion resistance.

In addition, when a metal substrate is polished by a physical polishing method, an abrasive having a particle size of 4 a.u or less is used. This is because the smoothness of the metal substrate is reduced and the surface roughness is increased when the abrasive particle size exceeds 4 a.u.

Preferably, the surface roughness value R _a of the upper metal substrate may be in the range of 0.5 μm or less, preferably 0.2 μm or less. The lower limit of R _a is not necessarily limited, but may be 0.1 μm.

The metal substrate in step (1) is not particularly limited as long as it has stability and compactness usable as a container, but is preferably selected from among carbon steel, aluminum, aluminum alloy, nickel, nickel alloy, copper, copper alloy, chromium and stainless steel. It may be any one selected, and more preferably, by using carbon steel, when considering economical efficiency and strength in addition to corrosion resistance, carbon steel can be used as a metal substrate.

In the present invention, step (2) is a step of plating nickel on the polished metal substrate to form a nickel plating film, wherein the Ni content of the metal substrate polished to a R _a of 0.5 μm or less is 85% or more. This is the step of plating the amount of Ni.

Formation of the nickel plating film may be performed by a general method such as electrolytic plating or electroless plating, and since the method is not limited, a description thereof is omitted.

In addition, before the step (2), if necessary, the polished metal substrate may be pretreated to remove impurities present on the surface and prevent the formation of an unnecessary oxidizing atmosphere. The pretreatment method may be performed by generally known chemical cleaning, commercial degreasing, dry etching, and the like.

In the present invention, step (3) is a step of forming a fluoride passivation film, and the nickel plating film is fluorinated to form a fluoride passivation film.

As the nickel plating film formed in step (2) is dense and has excellent surface roughness, during the fluorination treatment in step (3), a fluoride passivation film containing nickel fluoride is more stably formed, and the formed fluoride passivation film also has a high density. As it has, corrosion resistance and scratch resistance can be improved.

However, in order to form a fluorinated passivation film with enhanced fluorination treatment efficiency and acid resistance, preferably, before the fluorination treatment, the nickel plating film is treated with liquid or gaseous oxidizing substances such as H ₂ O ₂ , O ₃ , O ₂ , Air, and the like. After oxidation treatment with fluorination treatment, the fluorination treatment is carried out in a general way using chemicals containing a fluorine group, that is, substances such as HF, F ₂ , NF ₃ , CIF ₃ , CH ₃ F can be carried out by The temperature of the oxidation treatment is carried out for 2 to 24 hours at a temperature of 200 to 500 ℃. In addition, the fluorination treatment is 200 to 400 ℃, preferably 200 to 390 ℃, more preferably 250 to 380 ℃. In addition, the time of fluorination treatment is 1 to 12 hours. When the high-temperature oxidation fluoride treatment is performed in this way, a more dense fluoride passivation film can be formed on the nickel plating layer, and the fluoride passivation film contains nickel fluoride.

After the fluorination treatment, heat treatment may be performed at a temperature of 100 to 300°C, preferably 150 to 250°C. This heat treatment may be performed for 1 to 12 hours in an inert gas such as N ₂ , Ar, or He.

In addition, in the present invention, a fluorine passivation film is formed not only on the inner surface of the container but also on the valve that is inevitably touched when fluorine gas is discharged, so that pollutants are not generated from the valve when hydrogen fluoride gas is discharged from the storage container. The formation of a fluorinated passivation film on the valve is performed by aging for a certain period of time after charging a chemical with a fluoride group into a storage container, so that the valve mounted on the storage container is also at the same aging temperature In this state, by slowly removing chemicals with a fluorine group through the valve, not only the inner surface of the container but also the connected valve is treated with fluoride passivation to improve corrosion resistance and maintain high purity of the high-purity hydrogen fluoride stored inside the container. there is.

Hereinafter, examples will be described for more specific explanation of the present invention. However, the following examples are only preferred examples of the present invention and the present invention is not limited to the following examples.

<Example>

Example 1

The inner surface of a container made of carbon steel (Mn steel, standard 37Mn alloy) is polished so that the center line average roughness (R _a ) of the surface of the carbon steel inside the container is 0.5 μm, and then the Ni content on the surface of the carbon steel is 85% A nickel plated film having a thickness of 30 to 40 μm was formed on the surface of the carbon steel substrate by electroless plating with a high content of nickel.

Thereafter, in order to measure the corrosion resistance of the prepared storage container, it was filled with hydrogen fluoride having a purity of 99.99% and left at room temperature for 60 days. Thereafter, a portion of the stored hydrogen fluoride was collected and the concentration of the hydrogen fluoride was measured using a gas analyzer, and the results are shown in Table 1 below.

Example 2

In Example 1, the results are shown in Table 1 in the same manner as in Example 1, except that the center line average roughness (R _a ) of the surface of the carbon steel inside the container was 0.2 μm.

Example 3

After nickel plating in Example 1, while supplying 20% O ₂ to the nickel plating film at 1 L/min, the nickel plating film was oxidized at 350° C. for 12 hours, and then a container filled with 20% F ₂ diluted with N ₂ , and aged at 200° C. for 12 hours to oxidize and fluoride. Accordingly, a fluoride passivation film was formed to a thickness of 300 nm on the nickel plating film.

Thereafter, in order to measure the corrosion resistance of the prepared storage container, it was filled with hydrogen fluoride having a purity of 99.99% and left at room temperature for 60 days. Thereafter, a portion of the stored hydrogen fluoride was collected and the concentration of the hydrogen fluoride was measured using a gas analyzer, and the results are shown in Table 1 below.

Example 4

In Example 3, the fluorination temperature was set to 270 ° C., except that the oxidative fluorination treatment was performed at a high temperature, and the results are shown in Table 1.

Comparative Example 1

Except that the center line average roughness (Ra) of the carbon steel surface was 2 μm, the same procedure as in Example 1 was performed, and the results are shown in Table 1.

Comparative Example 2

Except that the center line average roughness (Ra) of the surface of the carbon steel was 1 μm, the same procedure as in Example 1 was performed, and the results are shown in Table 1.

Comparative Example 3

In Example 1, except that stainless steel (SUS316L) was used instead of carbon steel and nickel plating was not performed, the same procedure as in Example 1 was performed, and the results are shown in Table 1.

metal substrate metal substrate
Surface Ra (μm) Ni plating Fluorination temperature (℃) Hydrogen Fluoride Purity (%) Comparative Example 1 carbon steel 2 ○ - 98.89 Comparative Example 2 carbon steel One ○ - 99.25 Comparative Example 3 SUS316L 0.5 × - 99.93 Example 1 carbon steel 0.5 ○ - 99.97 Example 2 carbon steel 0.2 ○ - 99.98 Example 3 carbon steel 0.5 ○ 200 99.985 Example 4 carbon steel 0.5 ○ 270 99.99

According to Table 1, when the R _a of the carbon steel substrate was 0.5 μm or less, the purity of stored hydrogen fluoride was higher, and moreover, the purity of hydrogen fluoride was higher than that of SUS316L, which is known as a material with relatively strong corrosion resistance.

On the other hand, when the surface Ra of the metal substrate was 1 μm or more, despite the nickel plating, the purity of stored hydrogen fluoride was lower than that of SUS316L of Comparative Example 3, and Comparative Example 1, which had a higher Ra value, appeared lower.

It is presumed that this is because the surface roughness of the metal substrate affects the quality of plating, resulting in defects such as cracks or pinholes in the nickel plating film.

The present invention has been described above with reference to the accompanying drawings and embodiments, but these are merely exemplary, and those skilled in the art can make various modifications and equivalent other embodiments therefrom. will understand Therefore, the technical protection scope of the present invention should be determined by the claims below.

Claims (8)

As a container for storing high purity fluorine gas,
The container includes a material in which a nickel plating film is plated on the surface of a metal substrate to a thickness of 30 to 40 μm, and the nickel plating film is used as the inner surface of the container,
The metal substrate is a storage container for storing high-purity hydrogen fluoride, characterized in that the center line average roughness (R _a ) is 0.2 μm or less in surface roughness.
According to claim 1,
The metal substrate is a storage container for storing high-purity hydrogen fluoride, characterized in that carbon steel.
According to claim 1,
A storage container for storing high purity hydrogen fluoride, characterized in that a fluoride passivation film is formed on the surface of the nickel plating film.
According to claim 3,
A storage container for storing high-purity hydrogen fluoride, characterized in that the thickness of the fluoride passivation film is 0.1 ~ 1 ㎛.
As a method for manufacturing a container for storing high purity fluorinated gas,
(1) polishing the metal substrate constituting the inner surface of the storage container so that the center line average roughness (R _a ) of the surface of the metal substrate is 0.2 μm or less;
(2) plating nickel on the polished metal substrate to form a nickel plating film with a thickness of 30 to 40 μm; characterized in that it comprises a method for manufacturing a container for storing high-purity hydrogen fluoride.
According to claim 5,
After the step (2), (3) further comprising the step of forming a fluoride passivation film by treating the nickel plating film with fluoride.
According to claim 5,
The method of manufacturing a container for storing high-purity hydrogen fluoride, characterized in that the metal substrate in step (1) is carbon steel.
According to claim 6,
In the step of forming a passivated fluoride film of (3), before the fluoride treatment of the nickel plating film, the step of oxidizing the nickel plating film is further included.