Film Forming Apparatus and Film Forming Method

Abstract

To deposit an antibacterial film having an abrasion resistance and less coloration.SOLUTION: A film deposition apparatus includes: a vacuum chamber X that accommodates a substrate Z and to which a fluorine-containing gas is supplied; a high-frequency antenna 1 for generating a plasma in the vacuum chamber X; a transportation mechanism 2 that transports the substrate Z to the vacuum chamber X and transports a plasma-treated substrate Z from the vacuum chamber X; a conductive member 4 that is arranged around the substrate Z and has an ion passing hole h through which an ion can pass; and a power supply 5 for applying a negative voltage to the conductive member 4. The film deposition apparatus is configured such that an antibacterial film is deposited on the substrate Z by applying the negative voltage from the power supply 5 to the conductive member 4 so that the fluorine ion in a plasma passes through the ion passing hole h and is injected into the substrate Z.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a film-forming apparatus and a film-forming method for forming an anti-infection medium film such as an antibacterial film or an antiviral film on a substrate (hereinafter, in the present application, these films are simply described as "antibacterial films" as a concept including all of these films).

Background Art

[0002] Recently, various measures have been taken to prevent virus infection. For example, an antibacterial film is applied to a mask, a face guard, a mobile phone that a person touches with their hand, a cover case of the mobile phone, or a handrail.

[0003] As an antibacterial film, as shown in Patent Document 1, a fluorine coating is known. This repels moisture due to the water-repellent property of fluorine and prevents bacteria from adhering.

[0004] However, the fluorine coating is formed on the surface and peels off due to abrasion, reducing the antibacterial effect. In addition, for example, when a fluorine coating is applied to a transparent resin, there is also a problem that the resin is colored and the original properties of the fabric are impaired.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the present invention has been made to solve the above-described problems, and its main object is to form an antibacterial film that has abrasion resistance and can maintain its effect even after long-term use, and is less likely to be colored and hardly impairs the original properties of the fabric.

Means for Solving the Problems

[0007] That is, the film forming apparatus according to the present invention includes a vacuum chamber that houses a substrate and to which a fluorine-containing gas is supplied, a high-frequency antenna for generating plasma in the vacuum chamber, a transfer mechanism for carrying the substrate into the vacuum chamber and taking out the plasma-treated substrate from the vacuum chamber, a conductive member provided around the substrate and having ion passage holes through which ions can pass, and a power source for applying a negative voltage to the conductive member. By applying a negative voltage from the power source to the conductive member to allow fluorine ions in the plasma to pass through the ion passage holes and be implanted into the substrate, an antibacterial film is formed on the substrate.

[0008] According to the film forming apparatus configured as described above, since fluorine ions are implanted into the substrate to form an antibacterial film, the fluorine ions can be made to exist from the surface of the substrate to a deep portion. As a result, even if the substrate wears, fluorine ions continue to remain on its surface, so that an antibacterial film having wear resistance and maintaining its effect even after long-term use can be formed. Specific details will be described later. Furthermore, the antibacterial film formed in this way can suppress coloring compared to a fluorine coat and is less likely to impair the original properties of the fabric.

[0009] As a specific embodiment of the conductive member, a mesh-shaped mesh electrode is preferable.

[0010] It is preferable that the antennas are provided on both sides of the substrate, and the conductive members are provided between each antenna and the substrate. With such a configuration, an antibacterial film can be formed on both the front and back surfaces of the substrate at once.

[0011] The film-forming method according to the present invention is a film-forming method for forming an antibacterial film on a substrate. In this method, a fluorine-containing gas is supplied into a vacuum chamber that houses the substrate, and plasma is generated in the vacuum chamber. A pulse voltage is applied to the substrate or a high-voltage pulse application electrode provided around the substrate, thereby injecting fluorine ions into the substrate to form an antibacterial film.

[0012] According to such a film-forming method, since an antibacterial film is formed by injecting fluorine ions into the substrate, as described in the action and effect of the above-described film-forming apparatus, by allowing fluorine ions to exist from the surface of the substrate to a deep portion, an antibacterial film with wear resistance can be formed, and moreover, coloring of the substrate can be suppressed.

[0013] In order to sufficiently exhibit wear resistance, it is preferable that fluorine ions contained in the antibacterial film exist from the surface to at least a depth of 100 nm.

[0014] As a specific embodiment for injecting fluorine ions into the substrate, it is preferable that the pulse voltage is -5 kV or more and -1 kV or less.

[0015] In order to inject fluorine ions to a deeper portion of the substrate, it is preferable that the injection energy of the fluorine ions is 3 keV or more.

[0016] It is preferable that the substrate is in a sheet form, the substrate is sent from a feed roller into the vacuum chamber, and the substrate on which the antibacterial film is formed is wound by a take-up roller. According to such a method, an antibacterial film can be continuously formed on a sheet-shaped substrate, and the manufacturing efficiency and manufacturing speed can be improved.

Effects of the Invention

[0017] According to the present invention configured as described above, it is possible to form an antibacterial film that has wear resistance and can maintain its effect even after long-term use, and moreover, has little coloring and hardly impairs the original characteristics of the fabric.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0019] An embodiment of the film-forming method according to the present invention will be described below with reference to the drawings.

[0020] The film-forming method of this embodiment is for forming an antibacterial film against various viruses such as, for example, the coronavirus, and is used for, for example, face guards, mobile phones, mobile phone covers, protective films for displays, or handrails such as stairs, elevators, and escalators, antibacterial operating rooms, the walls of hospital rooms, handles, knobs, etc., antibacterial films to be pasted, or non-woven fabrics used for masks, futons, sofas, wear, hats, shoes, etc., and rubbers used for ornaments such as wristwatches, etc. It is a method for forming an antibacterial film to exhibit an antibacterial function.

[0021] <Device Configuration> First, the configuration of the plasma processing apparatus used for forming this antibacterial film on a substrate will be described. Note that, as the substrate, a sheet-like substrate made of an organic material such as PET, PP, PC, acrylic, etc. will be taken as an example for explanation.

[0022] As shown in FIG. 1, the plasma processing apparatus 100 of the present embodiment uses inductively coupled plasma (ICP) to perform plasma processing on a substrate.

[0023] Specifically, this plasma processing apparatus 100 includes a vacuum chamber X that houses a substrate Z, a high-frequency antenna 1 for generating plasma in the vacuum chamber X, a transfer mechanism 2 that transfers the substrate Z into the vacuum chamber X and discharges the plasma-processed substrate Z from the vacuum chamber X, and a high-frequency power supply 3 that applies high-frequency power to the high-frequency antenna 1.

[0024] The plasma processing apparatus 100 of the present embodiment is of a so-called roll-to-roll type, and the transfer mechanism 2 includes a delivery roller 21 that feeds out the sheet-shaped substrate Z into the vacuum chamber X and a take-up roller 22 that takes up the plasma-processed substrate Z.

[0025] Also, although the plasma processing apparatus 100 here is configured to transfer the substrate Z along the vertical direction, it may be configured to transfer the substrate Z along the horizontal direction.

[0026] Furthermore, as shown in FIG. 1, the plasma processing apparatus 100 of the present embodiment further includes a conductive member 4 provided around the substrate Z and having ion passage holes h through which ions can pass, and a power supply 5 that applies a negative voltage to the conductive member 4.

[0027] More specifically, the conductive member 4 is, for example, a mesh-shaped mesh electrode made of a metal such as SUS, and is, for example, in a flat plate shape in which a large number of meshes are formed as ion passage holes h.

[0028] In the present embodiment, as shown in FIG. 1, high-frequency antennas 1 are provided on each of the front surface side and the back surface side of the substrate Z, and a conductive member 4 is provided between each high-frequency antenna 1 and the substrate Z. These pair of conductive members 4 are electrically connected to each other, and a negative voltage is applied from a common power supply 5.

[0029] The power supply 5 applies a negative voltage for accelerating positive ions in the plasma to the conductive member 4. By this negative voltage acting as an acceleration voltage, the positive ions in the plasma are attracted to the conductive member 4 while being accelerated. Specifically, this power supply 4 is a high-voltage pulse power supply that generates a negative pulse voltage of -5 kV or more and -1 kV or less.

[0030] In addition, in this embodiment, a control unit (not shown) for controlling the above-described high-frequency power supply 3 and the power supply 5 is provided. Specifically, this control unit controls the high-frequency power supply 3 and the power supply 5 so as to apply a negative voltage from the power supply 5 to the conductive member 4 after stopping the high-frequency current applied from the high-frequency power supply 3 to the high-frequency antenna 1 and after a predetermined time has elapsed.

[0031] With such a configuration, when a fluorine-containing gas such as CF4 or ArF2 gas is supplied as a source gas to the vacuum chamber 2 and a high-frequency current is applied from the high-frequency power supply 3 to the high-frequency antenna 1, plasma is generated around the conductive member 4. The plasma referred to here means a state in which positive fluorine ions and electrons coexist.

[0032] When the above-described negative high-voltage pulse is applied from the power supply 5 to the conductive member 4, the electrons in the plasma are expelled from the conductive member 4, and positive fluorine ions are left around the conductive member 4. In this way, as the electrons are expelled from the conductive member 4, the plasma changes so as to gradually move away from the conductive member 4, and the boundary between this plasma and the region where the positive ions are left is called a sheath.

[0033] The fluorine ions left between this sheath and the conductive member 4 are attracted while being accelerated toward the conductive member 4 by the negative pulse voltage, that is, the acceleration voltage, applied to the conductive member 4, and some of the ions pass through the ion passage holes h (in this embodiment, the meshes formed in the mesh electrode) formed in the conductive member 4 and are implanted into the substrate Z in a high-energy state. As a result, the positive fluorine ions penetrate deeply from the surface into the interior of the substrate Z and bond with the substrate Z. Therefore, the antibacterial film formed by injecting these fluorine ions can be made less likely to peel off compared to, for example, a film formed by the CVD (Chemical Vapor Deposition) method.

[0034] <Manufacturing method> Next, a film-forming method for forming an antibacterial film on the surface of the substrate Z using the above-described plasma processing apparatus 100 will be described with reference to the flowchart of FIG. 2.

[0035] First, a fluorine-containing gas such as CF4 or ArF2 gas is supplied as a source gas to the vacuum chamber X, and the inside of the vacuum chamber X is maintained at, for example, 0.3 Pa or more and 10 Pa or less (S1).

[0036] Next, the substrate Z is fed into the vacuum chamber X by the feed roller 21, and high-frequency power from the high-frequency power supply 3 is applied to the high-frequency antenna 2 through a matcher (not shown), thereby generating discharge plasma containing fluorine ions in the vacuum chamber X (S2).

[0037] Subsequently, a negative pulse voltage of, for example, -5 kV or more and -1 kV or less is applied from the power supply 5 to the conductive member 4. As described above, electrons in the plasma are repelled from the conductive member 4, and positive fluorine ions remain around the conductive member 4.

[0038] Then, the fluorine ions remaining around the conductive member 4 are attracted while accelerating toward the conductive member 4 by the negative pulse voltage applied to the conductive member 4, and some of the ions pass through the ion passage holes h formed in the conductive member 4 and are injected into the substrate Z with an injection ion energy of 3 keV or more (S3).

[0039] By injecting these fluorine ions, water repellency due to fluorine can be exhibited on the surface of the substrate Z, and an antibacterial film is formed thereby.

[0040] Here, FIG. 3 shows the results of secondary ion mass spectrometry (SIMS) of the substrate on which the antibacterial film was formed by the above-described implantation of fluorine ions. From these analysis results, it can be seen that the antibacterial film formed by this film-forming method exists from the surface of the substrate Z to at least a depth of 400 nm. More specifically, this antibacterial film uses an acrylic plate as the substrate Z and has a secondary ion intensity (CPS: Counts Per Second) of 1E+03 (1000) or more at a depth of 400 nm from the surface.

[0041] Here, the results of evaluating the abrasion resistance of this antibacterial film will be described. In this abrasion resistance evaluation test, a sample was prepared by implanting fluorine ions into an acrylic plate at an implantation ion energy of 5 keV to form an antibacterial film as described above, and a brushing abrasion test using a toothbrush was performed on this sample. Specifically, the sample was rubbed over a distance of about 4 km at a speed of 40 mm / second with a load of 500 g applied to the toothbrush.

[0042] As a result of this abrasion positive evaluation test, as shown in FIG. 4, it was confirmed that fluorine ions remained in the surface layer of the substrate Z even after abrasion of 4 km.

[0043] According to such a film-forming method, since fluorine ions are implanted into the substrate Z to form an antibacterial film, the fluorine ions can be made to exist from the surface of the substrate Z to a deep portion. As a result, even if the substrate Z is abraded, fluorine ions continue to remain on its surface, so that an antibacterial film with abrasion resistance can be formed. Moreover, the antibacterial film formed in this way can suppress coloring compared to a fluorine coat and can also solve the problem of impairing the designability.

[0044] Note that the present invention is not limited to the above-described embodiment.

[0045] For example, in the above-described embodiment, the antibacterial film formed on an acrylic plate was described, but an antibacterial film may be formed on other substrates such as rubber.

[0046] In addition, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit thereof.

Explanation of Reference Numerals

[0047] 100 ··· Plasma processing apparatus X ··· Vacuum chamber Z ··· Substrate 1 ··· High-frequency antenna 2 ··· Conveying mechanism 3 ··· High-frequency power supply 4 ··· Conductive member 5 ··· Power supply

Claims

1. A vacuum chamber that houses a substrate and to which a fluorine-containing gas is supplied, a high-frequency antenna for generating plasma in the vacuum chamber, a transport mechanism for transporting the substrate into the vacuum chamber and transporting the plasma-treated substrate out of the vacuum chamber, a conductive member provided between the substrate and the high-frequency antenna and having an ion passage hole through which ions can pass, and a power source for applying a negative pulse voltage to the conductive member, wherein, in a state where no negative pulse voltage is applied to the substrate, a negative pulse voltage is applied from the power source to the conductive member to allow fluorine ions in the plasma to pass through the ion passage hole and be implanted into the substrate, thereby forming an antibacterial film on the substrate. A film-forming apparatus characterized by this.

2. The film-forming apparatus according to claim 1, wherein the conductive member is a mesh-shaped mesh electrode.

3. The high-frequency antenna is provided on each of both sides of the substrate, The film-forming apparatus according to claim 1 or 2, wherein the conductive member is provided between each antenna and the substrate.

4. A film-forming method for forming an antibacterial film on a substrate, wherein a fluorine-containing gas is supplied into a vacuum chamber that houses the substrate, and plasma is generated in the vacuum chamber by a high-frequency antenna, in a state where no negative pulse voltage is applied to the substrate, a negative pulse voltage is applied to a conductive member provided between the substrate and the high-frequency antenna and having an ion passage hole through which ions can pass, allowing fluorine ions in the plasma to pass through the ion passage hole, injecting fluorine ions into the substrate to form an antibacterial film. A film-forming method characterized by this.

5. The film-forming method according to claim 4, wherein fluorine ions contained in the antibacterial film are present from the surface to at least a depth of 100 nm.

6. The film-forming method according to claim 4 or 5, wherein the pulse voltage is -5 kV or more and -1 kV or less.

7. The film-forming method according to any one of claims 4 to 6, wherein the implantation energy of the fluorine ions is 3 keV or more.

8. The substrate is in the form of a sheet, The film-forming method according to any one of claims 4 to 7, wherein the substrate is fed from a feed roller into the vacuum chamber, and the substrate on which the antibacterial film is formed is wound up by a take-up roller.

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