JPH11165375A - Material having fluoroplastic formed on surface fluorinated passivated film and various devices and parts using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material capable of being inexpensively and easily produced within a short time, capable of forming a thick fluorocarbon film only on an objective surface, having sufficient corrosion resistance against corrosive gas or semiconductor process gas such as special gas or the like, especially, against plasma and a chemical soln. and having fluoroplastic formed on the surface of a fluorinated passivated film transmitting ultrasonic waves. SOLUTION: A fluorinated passivated film is provided on the surface of a base metal material and fluoroplastic is formed on the surface of the fluorinated passivated film by electrostatic powder coating. Or, the fluorinated passivated film is provided on the surface of the base metal material and fluoroplastic is formed on the surface of the fluorinated passivated film by electrostatic powder coating to be irradiated with plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material in which a fluororesin is formed on the surface of a fluorinated passivation film, and various devices and parts using the material.

[0002]

2. Related Art Conventionally, in a semiconductor dry process, an apparatus such as a process chamber made of stainless steel or aluminum has been used without surface treatment. However, the use of various corrosive gases causes corrosion of the inner surface of the chamber, which causes a problem in process uniformity every time. Also, Ni
When a chamber having F ₂ as a surface is used, there is a problem that a gas having hydrogen radicals, for example, a gas such as SiH ₄ has catalytic properties, and the NiF ₂ film is reduced.

On the other hand, in a semiconductor wet process, an apparatus for supplying ultrapure water or a chemical solution or performing cleaning or the like using such a substance is made of a resin material having corrosion resistance such as Teflon (tetrafluoroethylene polymer). Commonly used. However, there is a problem that the resin material is softer than metal and is easily broken. In addition, since a resin material such as Teflon is permeable to chemical vapor, there is a problem in that the transmitted chemical vapor corrodes instruments and external metal parts. Furthermore, since an apparatus using a resin material such as Teflon absorbs ultrasonic waves, there is a problem that cleaning using ultrasonic waves is impossible.

In order to solve the above problems, a metal substrate is subjected to a fluoridation passivation surface treatment, and a fluorocarbon gas such as CF ₄ , C ₂ F ₆ , C ₃ F ₈ is applied to the fluoridation passivation surface. There is known a technique of supplying a fluorocarbon film formed by thermal CVD or plasma CVD (JP-A-5-104672).

However, with these techniques, it is impossible to form a fluorocarbon film uniformly on a device having a large size or a complicated shape in the future.

Further, it takes a lot of time to form a fluororesin film on the order of several microns on a fluorinated passivation film by the conventional technique. Further, this is an effect of the CVD apparatus itself, and accordingly, the formation of the fluororesin film increases costs.

[0007]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a fluorocarbon film which can be manufactured in a short time, at a low cost and easily, and which can form a thick fluorocarbon film only on a target surface. An object is to provide a material in which a fluororesin is formed on the surface of a passivation film, and various devices and parts using the material.

The present invention forms a fluororesin on the surface of a fluorinated passivation film which has sufficient corrosion resistance to corrosive gases such as special gases and process gases for semiconductors, especially plasma and chemicals, and which transmits ultrasonic waves. It is an object of the present invention to provide a material obtained and various devices and parts using the material.

[0009]

The fluororesin-forming material of the present invention has a fluorinated fluorinated passivation film on the surface of a base metal material, and the surface of the fluorinated passivation film has an electrostatic powder. It is characterized in that a fluororesin formed by body painting is formed.

The material on which the fluororesin of the present invention is formed is
It has a fluorinated fluorinated passivation film on the surface of the base metal material, and the surface of the fluorinated passivation film is formed by electrostatic powder coating, and is formed of a fluororesin that has been subjected to plasma irradiation. Features.

The chemical liquid device of the present invention is characterized in that the above-mentioned or the above-mentioned fluororesin-formed material is used for a liquid contact portion of a chemical liquid device which is a device for storing, distributing, or reacting or cleaning a chemical solution. Features.

In the gas device of the present invention, a fluororesin is applied to the gas-contacting portion of a gas device, which is a gas storage, gas delivery, vacuum pump, or gas reaction device, on the above-mentioned fluoridation passive film. It is characterized by using a material that has been used.

A fluid contact part according to the present invention is characterized in that at least a fluid contact part is formed from the material described in claim 1.

[0014]

According to the present invention, by forming a fluorocarbon film on the surface of a metal material in contact with a chemical solution in a wet process, it is possible not only to prevent corrosion of devices and components by the chemical solution but also to prevent contamination of the chemical solution. . Further, since a metal material is used for the base, cleaning using ultrasonic waves becomes possible. In a dry process, a process chamber, piping, and the like can have resistance to corrosive gas and plasma.

The base metal of the present invention includes various metals, particularly, stainless steel, nickel, aluminum or an alloy of these with other metals, and a semimetal containing nickel on the surface thereof, such as nickel-metal. Phosphorus-plated ones are also used.

The formation of fluorinated passivation may be carried out, for example, by the following method.

That is, the metal material from which the natural oxide film existing on the surface has been removed is baked in an inert gas of high purity (preferably, the impurity concentration is several ppb or less) to remove moisture adsorbed on the metal surface. After elimination, it is fluorinated to form a fluorinated passivation film made of metal fluoride on at least a part or the entire surface thereof, and again under an inert gas atmosphere of high purity (preferably, impurity concentration is several ppb or less). Heat treatment.

The baking temperature is not particularly limited as long as it can remove adhering moisture. For example, stainless steel,
35 for nickel, nickel alloy, copper, copper alloy, chromium, cobalt, cobalt alloy, titanium, titanium alloy
0-600 degreeC is preferable and 400-500 degreeC is more preferable. The baking time is preferably 1 to 5 hours. When the baking temperature is lower than 350 ° C., the moisture adhering to the surface of the base material of the metal material is not completely removed, and the fluorinated passivation film formed by performing fluorination in such a state is, for example, nickel. NiF ₂ .4H ₂ O, and a perfect fluorinated passivation film satisfying the stoichiometric ratio may not be obtained.
Baking temperature of aluminum and aluminum alloy is 1
50-400 ° C is preferred, and 200-300 ° C is more preferred.

The fluorination temperature is preferably from 200 to 500 ° C, more preferably from 250 to 450 ° C, for nickel, monel, copper, copper alloy and chromium. The fluorination time is preferably 1 to 5 hours. Fluorination temperature is 20
If the temperature is lower than 0 ° C., a fluorinated passivation film having a sufficient thickness and excellent corrosion resistance may not be obtained. Further, when fluorination is performed at a temperature higher than 450 ° C., for example, in the case of nickel, nickel fluoride crystal grains are generated in the formed fluorinated passivation film, and the passivation film may be cracked or peeled off. Hastelloy C
The fluorination temperature is preferably from 150 to 300 ° C,
~ 250 ° C is more preferred. When fluorinated at a temperature higher than 300 ° C., peeling occurs and a fluorinated passivation film having excellent corrosion resistance may not be obtained.

The fluorination temperature of stainless steel is 100 to 30
0 ° C is preferable, and 150 to 265 ° C is more preferable. The fluorination time is 1 to 5 hours. Fluorination temperature is 2
If the temperature is lower than 65 ° C., FeF ₂ is generated, and if the temperature exceeds 265 ° C., FeF ₃ is generated. When a large amount of FeF ₃ is formed, F
Since the bulk density of eF ₂ is 1.16 times as large as that of FeF ₃ , the formed film expands in volume, and cracks and peeling may occur. If the temperature is lower than 100 ° C., a sufficient film thickness cannot be obtained. The fluorination temperature of aluminum or aluminum alloy is preferably from 200 to 400 ° C, and from 250 to 350 ° C.
C is more preferred. When fluorinated at a temperature higher than 400 ° C., crystal grain boundaries of aluminum fluoride are generated in the formed fluorinated passivation film, and cracks and peeling occur.

The fluorination is basically carried out at normal pressure,
If necessary, it can be carried out under pressure, and the pressure at this time may be about 2 atm or less in gauge pressure. The fluorination atmosphere is preferably performed in the absence of oxygen,
Therefore, it is preferable to use fluorine alone or diluted with an appropriate inert gas, for example, N ₂ , Ar, He or the like.

The passive film of as-fluorinated nickel fluorinated at the fluorination temperature is formed by Surface Science In
ESCA of SSX-100 manufactured by instruments' Products
As a result, the ratio of Ni to F was about 1.1 times the stoichiometric ratio of NiF ₂ . That is, the amount of fluorine with respect to nickel is about 1.1 times in excess,
This excess fluorine is present in the passivation film in a free state without binding to nickel. Since this excess amount impairs corrosion resistance, it cannot be a corrosion-resistant material.

The heat treatment after the fluorination treatment is 300 to 6 for nickel, nickel alloy, copper, copper alloy and chromium.
00 ° C, preferably 400 to 500 ° C. In the case of stainless steel, 200 to 600 ° C. is preferable, and 300 to
500 ° C. is more preferred. In the case of aluminum and aluminum alloy, the temperature is preferably 200 to 400 ° C, and 250 to 400 ° C.
400 ° C. is more preferred. By performing heat treatment in an inert gas such as N ₂ , Ar, or He for 1 to 5 hours, it satisfies a substantially stoichiometric ratio that is robust, dense, has good adhesion to metal, and has sufficient corrosion resistance. To form a fluorinated passivation film.

On the other hand, as a fluororesin used for electrostatic powder coating, FEP (tetrafluoroethylene-hexafluoropropylene copolymer) fluororesin or PFA (tetrafluoroethylene-perfluorovinyl ether copolymer)
Fluororesin or the like is used.

In the surface treatment film of the present invention, first, a metal material is subjected to a fluoridation passivation treatment to form a fluoridation passivation film, and then a fluorocarbon film is formed by an electrostatic powder coating method. It is preferably formed by performing plasma irradiation treatment of gas.

Electrostatic powder coating is a process in which a fluororesin powder charged by applying an applied voltage is sprayed onto a substrate to cause the fluororesin to adhere to the surface of the fluorinated passivation film. _2, Ar, 380 ° C. in He, etc., 20
A heat treatment is performed for a minute to form a fluorocarbon film. The film thickness can be controlled by the amount of static electricity.

Conventionally, when performing fluororesin coating, it was impossible to apply resin powder unless blasting or primer treatment was performed on the substrate surface. However, when a fluorinated passivation film is formed, it is possible to form a fluororesin with good adhesion without performing a conventional surface treatment such as a blast treatment or a primer treatment. Was found. When a fluorinated passivation film is formed on the substrate surface, the outermost surface of the fluorinated passivation film is terminated with fluorine, which increases the adhesion with the fluororesin and enables the fluororesin to be formed with good adhesion It is thought that it became. In particular, the adhesion is better when the fluorinated passivation is a fluorinated passivation that satisfies a substantially stoichiometric ratio.

Further, a fluororesin-coated one is 60 eV
By irradiating the plasma using the CF-based gas for 30 minutes, the adhesion between the fluororesin and the fluorinated passivation film formed on the metal substrate is further improved. However, as the CF-based gas, a gas such as CF ₄ or C ₄ F ₈ is preferable.

As for the irradiation energy, if the energy is too large, the surface of the fluorocarbon film is destroyed.
７０70 eV.

Next, the device of the present invention will be described.

The apparatus of the present invention is basically made of a metal material having the above-mentioned fluorocarbon film formed on a portion which comes into contact with a chemical solution and a corrosive gas, and a material on which the above-mentioned fluorocarbon film is formed also on a portion which does not make contact. May be used.

The chemical solution device is used as a broad concept including all devices for handling a chemical solution, and examples thereof include a device for storing or transporting a chemical solution, and a reaction device that uses a chemical solution or mixes a chemical solution. it can.
More specifically, tanks, piping, valves, pumps, vessels,
It is a cleaning device.

The gas device is used as a broad concept including all devices that handle gas. For example, a gas storage or gas distribution device, or a reaction device that uses gas or generates gas, is used. Can be illustrated. More specifically, a cylinder, a gas holder, a pipe, a valve, a vacuum pump, an RIE reactor, and a CVD reactor.

FIG. 1 is a schematic view of a cleaning device as an example of a chemical solution device. The apparatus includes a cleaning container 103 and a chemical supply pipe 10.
1. Ultrapure water pipe 102, chemical liquid circulation pump 105, chemical liquid circulation pipe 106, and ultrasonic device 107. A fluorocarbon film 10 is provided on the inner wall of the cleaning vessel 103.
4 are formed. The fluorocarbon film on the inner wall of the cleaning vessel 103 was formed by first electrolessly plating nickel-phosphorus on the inner wall of an aluminum alloy cleaning vessel by 10 μm and subjecting it to fluoridation passivation to form a 2000 μm NiF ₂ film. Next, a fluororesin is applied by electrostatic powder application,
The fluorocarbon film is formed by performing a heat treatment at 380 ° C. for 20 minutes in a nitrogen atmosphere.

FIG. 2 is a schematic view showing an example of the gas apparatus. The apparatus includes a gas storage cylinder 201, and a gas supply system 202 incorporating a valve, a mass flow controller, and the like.
And a reaction device 20 such as an RIE device or a CVD device
3 and a vacuum exhaust device 205. A fluorocarbon film 204 is formed on the inner wall of the reactor. The formation of the fluorocarbon film on the inner wall of the reactor 203
First, put nickel-phosphorus on the inner wall of the aluminum alloy washing container.
Electroless plating of 0 μm was performed, and fluoridation passivation treatment was performed to form a NiF ₂ film at 2000 °. Next, a fluororesin is applied by electrostatic powder coating,
The fluorocarbon film is formed by performing a heat treatment at 20 ° C. for 20 minutes.

[0036]

EXAMPLES In order to clarify the technical contents of the present invention,
A representative example will be described below as an example.

(Example 1) First, nickel was placed on an aluminum base.
-Phosphor plating was applied to a thickness of 10 μm, and fluoridation passivation treatment was performed to form a NiF ₂ film at 2000 °. Then PFA
Resin is applied by electrostatic powder coating, and then
By performing a heat treatment at 0 ° C. for 20 minutes, a fluorocarbon film having a thickness of 30 μm was formed. A cross-sectional view is shown in FIG.

(Example 2) After Reference Example 1, 30
Surface treatment was performed by irradiating 60 eV of CF ₄ plasma for one minute.

The sample manufactured in Example 1 (Sample 1) and the sample manufactured in Example 2 (Sample 2)
The following survey was conducted.

(Conventional Example 1) Chemical resistance: HF sample 1 was immersed in a 0.5% HF solution containing a highly corrosive and permeable nonionic surfactant at room temperature for 20 hours, and then subjected to corrosion resistance. Sex was investigated. FIG. 4 shows surface observation using an electron microscope (hereinafter, referred to as SEM). It was confirmed that no change was observed before and after the immersion.

Ozone-Resistant Water Resistance Sample 1 was immersed in ozone water having an ozone concentration of 5 ppm for 12 hours in order to investigate the resistance to the most oxidizing ozone. FIG. 5 shows a surface observation using an optical microscope. From this result, it was confirmed that there was no change before and after immersion.

Dewatering Properties Resins generally have poor dewatering properties. For use in a gas device or a vacuum device, the dehydration characteristics of the inner wall of the pipe and the inner wall of the chamber are most important. The sample 1 was inserted into a stainless steel pipe, and the dehydration content when the temperature was raised to 250 ° C. was measured by an atmospheric pressure type mass spectrometer (API-MS).

At that time, Ar gas was used as a carrier gas, and the flow rate was 1.2 L / m. The same test was performed using a sample (sample 3) having a NiF ₂ film on which an aluminum substrate was plated with nickel-phosphorus and whose surface was subjected to fluoridation passivation as a comparative material.

FIG. 6 shows the results of the dehydration measurement. Although the initial moisture content of Sample 1 having the fluorocarbon film was larger than that of the sample not having the fluorocarbon, the water withering time was the same. It was confirmed that the fluorocarbon film could be used as a vacuum device.

Corrosion resistant gas: Cl ₂ , CO, HF Samples 1 to 3 were inserted into stainless steel pipes, filled with Cl ₂ gas, and sealed at room temperature for 100 hours.

The surface of the subsequent sample 1 was evaluated by SEM. Evaluation was performed by SEM using various gases, CO, and HF in the same manner.

Table 1 shows the results. It was confirmed that all gases had excellent corrosion resistance.

[0048]

[Table 1] ◎: No corrosion Plasma resistant property 1: CF ₄ , C ₄ F ₈ , NF ₃

Various CFs of 60 eV were applied to Samples 1, 2 and 3.
₄ plasma, C ₄ F ₈ plasma, and NF ₃ plasma were irradiated for 30 minutes, and the plasma resistance of each was investigated.

As a result of surface observation by SEM, it was confirmed that there was no change in the surface before and after irradiation. Table 2 shows the results.

Plasma resistant property 2: Since the H ₂ NiF ₂ film has catalytic properties for H ₂ ,
There was a problem that the _two films decreased. Then, the resistance to H radical was investigated by attaching a fluorocarbon film.

The samples 1, 2 and 3 were irradiated with plasma of the next gas species of 40 eV for 30 minutes. The result of surface observation by SEM confirmed that no change in the surface was observed before and after irradiation. Table 2 shows the results.

[0053]

[Table 2] ◎: No change before and after irradiation ○: Slight change before and after irradiation

Adhesion test The sample 1 was irradiated with megasonic at 950 kHz and 600 W for 8 hours in ultrapure water for 8 hours, and the adhesion between the substrate and the fluorocarbon film was examined. No bubbles or bubbles were generated.

According to the adhesion test of JIS,
The surface was scratched in a checkerboard shape with a cutter, and the adhesion was examined by a method of peeling off the surface with a gum tape. As a result, film peeling was not confirmed.

At the same time, the same test was conducted on Sample 2, and no film peeling was confirmed.

[0057]

[Table 3]

Ultrasonic Transmittance A 950 kHz vibrator was adhered to a 20 cm × 15 cm square, 3 mm thick aluminum plate treated in the same manner as in Sample 1, and the resonance frequency was measured.

The same experiment was conducted using a material not coated with a fluororesin (sample 4) as a comparative material.

Table 3 shows the results. It was confirmed that both the fluororesin-coated and non-fluororesin-coated ones can be used as a vessel for ultrasonic cleaning because the deviation of the resonance frequency from the vibrator is within an allowable range.

[0061]

[Table 4] However, tolerance range 950kHz ± 65Hz, aluminum plate thickness 3 ± 0.1mm

[0062]

According to the present invention, it is possible to easily apply a fluororesin by forming a fluoride passivation film on the substrate (electrostatic powder coating). Further, in the future, it is possible to perform uniform fluorine coating irrespective of an increase in the size and complexity of the device. It was confirmed that the formed fluorocarbon film had resistance to a chemical solution such as a hydrofluoric acid aqueous solution showing strong solubility in a semiconductor wet process.

In the conventional wet cleaning of a semiconductor, a resin material is used, and there is a problem that the resin is softer and more easily damaged than a metal. However, forming a fluorocarbon film on a metal substrate increases mechanical strength. Wet cleaning using ultrasonic waves has become possible. On the other hand, in the semiconductor dry process, it was confirmed that the carbon nanotube had corrosion resistance by performing fluorocarbon treatment on a pipe using a corrosive gas such as a special gas, a process chamber inner surface, or a vacuum pump material such as a turbo molecular pump. The present invention can be expected to have a great effect in wet processes and dry processes in the semiconductor field.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a chemical solution device.

FIG. 2 is a schematic diagram of an example of a gas device.

FIG. 3 is a cross-sectional view of Sample 1.

FIG. 4 is an SEM photograph of Sample 1.

FIG. 5 is an optical micrograph of the material of Sample 22.

FIG. 6 is a graph showing the dehydration characteristics of each sample.

[Explanation of symbols]

 101 ... Chemical liquid supply pipe 102 ... Ultra pure water supply pipe 103 ... Cleaning container 104 ... Fluorocarbon membrane 105 ... Pump 106 ... Chemical liquid circulation pipe 107 ... Ultrasonic apparatus 201 ... Bomb 202 ... Gas supply pipe 203 ... Reactor 204 ... Fluorocarbon membrane 205 ... Vacuum pump

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/3065 H01L 21/302 B (72) Inventor Yuhisa Nitta 4-1-1 Hongo, Bungo-ku, Tokyo Ultra Clean Technology Development Research Co., Ltd. In-house (72) Inventor Hiroshi Yazaki Aoba-ku, Aoba-ku, Aoba-ku, Sendai-shi, Miyagi (No address) Inside Tohoku University

Claims (5)

[Claims] 1. A fluorinated fluorinated passivation film is provided on a surface of a base metal material, and a fluorinated resin formed by electrostatic powder coating is formed on the surface of the fluorinated passivation film. A material formed of a fluororesin. 2. A fluorinated fluorinated passivation film is formed on the surface of a base metal material, and a fluororesin is formed on the surface of the fluorinated passivation film by plasma irradiation after being formed by electrostatic powder coating. A material formed with a fluororesin, which is characterized in that: 3. The liquid contacting part of a chemical solution device which is a device for storing a chemical solution, distributing a chemical solution, or reacting and cleaning a chemical solution.
Or a liquid chemical device using the material formed with the fluororesin according to 2 above. 4. A material in which the fluororesin according to claim 1 or 2 is applied to a gas contact portion of a gas device which is a gas storage, gas delivery, vacuum pump, or gas reaction device. And gas equipment. 5. The method according to claim 1, wherein at least the fluid contact portion is provided.
Tanks, piping, valves, pumps, containers, characterized by being formed from the material formed fluororesin described
Wetted parts such as cylinders and gas holders.