JP7632375B2 - Metal film deposition equipment - Google Patents

Description

The present invention relates to a film forming device that forms a metal film on the surface of a substrate.

Conventionally, a metal coating has been formed by precipitating a metal on the surface of a substrate (for example, Patent Document 1). Patent Document 1 describes a film-forming device that includes a metal anode, a solid electrolyte membrane (hereinafter also referred to as electrolyte membrane) arranged on the surface of the anode, and a power supply unit that applies a voltage between the anode and the substrate, with the substrate serving as the cathode. In this film-forming device, a voltage is applied between the anode and the substrate using the power supply unit while the electrolyte membrane, which is impregnated with a solution containing metal ions, is in contact with the substrate. As a result, the metal ions impregnated in the electrolyte membrane move to the substrate in contact with the electrolyte membrane and are reduced on the surface of the substrate. As a result, the metal is precipitated on the surface of the substrate, and a metal coating is formed.

JP 2014-122377 A

The positive and negative electrodes of the power supply unit are electrically connected to the substrate as the anode and cathode via conductors. As such, the deposition device requires wiring to deposit the metal film, which may complicate the configuration of the deposition device.

The present invention was made in consideration of these points, and its purpose is to provide a metal film deposition device with a simpler configuration.

In consideration of the above-mentioned problems, the metal coating deposition device according to the present invention comprises an anode, a solid electrolyte membrane disposed between the anode and a substrate, a power supply unit that applies a voltage between the anode and the substrate using the substrate as a cathode, and an insulating container that covers an opening on the substrate side with the solid electrolyte membrane, accommodates the anode at a position spaced apart from the solid electrolyte membrane so as to be freely slidable in a direction toward the solid electrolyte membrane, and accommodates an electrolytic solution containing metal ions between the solid electrolyte membrane and the anode, and applies a voltage between the anode and the substrate with the solid electrolyte membrane in contact with the substrate, thereby reducing the metal ions contained inside the solid electrolyte membrane. A metal film forming device that forms a metal film derived from the metal ions on the surface of the substrate, the film forming device is equipped with a conductive cap that covers the container from the anode side, and an elastic body arranged between the cap and the anode, the positive electrode of the power supply unit is connected to the anode, the negative electrode of the power supply unit is connected to the cap, the end of the cap is formed to be separated from the substrate when the solid electrolyte membrane is in contact with the substrate, and the elastic body is freely compressively deformed by pressing the cap toward the anode side until the end face of the cap comes into contact with the substrate.

In the film forming device according to the present invention, the end of the cap is spaced from the substrate while the solid electrolyte membrane is in contact with the substrate. In this state, when the cap is pressed toward the anode, the elastic body is compressed and deformed, and the anode is urged by the elastic body in a direction toward the solid electrolyte membrane. This causes the anode to slide within the container in a direction toward the solid electrolyte membrane. As a result, the liquid pressure of the electrolyte solution contained between the anode and the solid electrolyte membrane increases, allowing the solid electrolyte membrane to conform to the surface of the substrate.

When the cap is pushed further toward the anode, the end face of the cap comes into contact with the substrate. As a result, the substrate is electrically connected to the negative pole of the power supply through the cap, and a voltage is applied between the anode and substrate. In this way, with the above-mentioned film-forming device, simply by pushing the cap toward the anode, the solid electrolyte film conforms to the surface of the substrate and the formation of the metal film can begin.

According to the present invention, the configuration of a metal film deposition device can be simplified.

1 is a schematic cross-sectional view of a metal film forming apparatus according to an embodiment of the present invention, showing a state in which a cap is separated from a substrate. 2 shows a state in which the cap is in contact with the substrate in the film forming apparatus of FIG. 1. 2 is a flowchart illustrating a method for forming a metal film using the film forming apparatus of FIG. 1 . FIG. 11 is a schematic cross-sectional view of a metal film forming apparatus according to another embodiment of the present invention, showing a state in which the cap is separated from the substrate.

The following describes a metal film deposition device according to an embodiment of the present invention with reference to the drawings.

Figure 1 is a schematic cross-sectional view of a metal film deposition apparatus 1 according to an embodiment of the present invention, showing a state in which a cap 17 is separated from a substrate B. Figure 2 shows a state in which the cap 17 is in contact with a substrate B in the deposition apparatus 1 of Figure 1.

1 and 2, the film forming apparatus 1 includes an anode 11, a solid electrolyte membrane (hereinafter also referred to as electrolyte membrane) 13 disposed between the anode 11 and the substrate B, a battery (power supply unit) 14 that applies a voltage between the anode 11 and the substrate B with the substrate B as the cathode, and an insulating container 15 that contains an electrolytic solution L containing metal ions. The positive electrode 14a of the battery 14 is connected to the anode 11 via an anode current conductor 19 described later, and the negative electrode 14b of the battery 14 is connected to a cap 17 described later.

As shown in FIG. 2, the film forming apparatus 1 is an apparatus that applies a voltage between the anode 11 and the substrate B while the electrolyte membrane 13 is in contact with the substrate B, and reduces the metal ions contained inside the electrolyte membrane 13 to form a metal film derived from the metal ions on the surface B1 of the substrate B. In this embodiment, for convenience of explanation, the positional relationship of the components of the film forming apparatus 1 is specified on the assumption that the electrolyte membrane 13 is placed below the anode 11, and the substrate B is placed further below that. However, as long as a metal film (not shown) can be formed on the surface B1 of the substrate B, this is not limited to this positional relationship, and for example, the film forming apparatus 1 in FIG. 1 may be upside down.

The substrate B may be any material that functions as a cathode (i.e., a surface having electrical conductivity). The substrate B has a surface B1 that faces the electrolyte membrane 13. The material of the substrate B is not particularly limited as long as it functions as a cathode (i.e., a surface having electrical conductivity), and may be made of a metal material such as aluminum or iron, or may have a surface of a resin, ceramic, or the like coated with a metal layer such as copper, nickel, silver, or iron.

The anode 11 has a shape corresponding to the film-forming region of the substrate B. The film-forming region of the substrate B means the portion of the surface B1 of the substrate B facing the anode 11. The anode 11 is made of the same metal as the metal film. The anode 11 may be non-porous (for example, non-porous) or porous. When a non-porous anode 11 is used, the metal film formed on the substrate B is less susceptible to the surface condition of the anode 11. The anode 11 may be block-shaped or flat. The anode 11 is soluble in the electrolyte L, and the anode 11 dissolves when a voltage is applied using the battery 14. Examples of materials for the anode 11 include copper, nickel, and silver.

The film forming apparatus 1 includes an anode conductor 19 disposed between the anode 11 and the battery 14. The anode conductor 19 is disposed so as to be in direct contact with the anode 11, and electrically connects the anode 11 to the positive electrode 14a of the battery 14. The anode conductor 19 may be in the shape of a block or a plate, and examples of the material include titanium and stainless steel. The passive film formed on the surface of the anode conductor 19 can suppress rust from occurring on the anode 11.

The electrolyte L is a liquid that contains the metal of the metal film to be formed in an ionic state, and examples of such metals include copper, nickel, and silver. The electrolyte L is an aqueous solution in which such metals are dissolved (ionized) with an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, or pyrophosphoric acid. For example, when the metal is copper, examples of the electrolyte L include an aqueous solution containing copper sulfate, copper pyrophosphate, and the like.

The electrolyte membrane 13 is a flexible membrane that can be impregnated (contained) with metal ions by contacting it with the electrolytic solution L. The electrolyte membrane 13 is not particularly limited as long as the metal ions can be reduced in the substrate B when a voltage is applied from the battery 14, and a metal derived from the metal ions can be precipitated. Examples of the material of the electrolyte membrane 13 include fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins with ion exchange functions such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd.

The container 15 has a cylindrical shape and is made of an insulating material. The container 15 includes a lower opening (opening) 15a that opens toward the substrate B (i.e., downward) and an upper opening 15b that opens toward the opposite side of the substrate B (i.e., upward). The container 15 covers the lower opening 15a that opens toward the substrate B with the electrolyte membrane 13, and accommodates the anode 11 and the anode current conductor 19 at a position spaced apart from the electrolyte membrane 13. The anode 11 and the anode current conductor 19 are accommodated in the container 15 so as to be slidable in the direction toward the electrolyte membrane 13. The inner wall surface of the container 15, the anode 11, and the electrolyte membrane 13 form a storage space 15c, and the electrolyte solution L is accommodated in the storage space 15c. As shown in FIG. 1, the container 15 is structured so that the electrolyte solution L accommodated in the storage space 15c directly contacts the anode 11 and the electrolyte membrane 13. The container 15 is made of a material that is insoluble in the electrolyte L.

As shown in Figures 1 and 2, the film forming apparatus 1 further includes a cap 17, a spring (elastic body) 18, an attachment member 24, and an insulating cover 20.

The cap 17 has a bottomed cylindrical shape and is made of a conductive material. The cap 17 includes a substrate side opening 17c that opens toward the substrate B, a blocking portion 17d that covers the container 15 from the anode 11 side on the opposite side of the substrate side opening 17c, and a side wall portion 17e that extends from the blocking portion 17d toward the substrate B. The cap 17 has an internal space 17f partitioned by the inner wall surfaces of the blocking portion 17d and the side wall portion 17e. The cap 17 has an end surface 17b facing the substrate B at the end portion 17a on the substrate B side of the side wall portion 17e. As shown in FIG. 1, the end portion 17a of the cap 17 is formed so as to be separated from the substrate B with the electrolyte membrane 13 in contact with the substrate B. The cap 17 accommodates the container 15, an elastic body 18 described later, and a battery 14 in the internal space 17f. The battery 14 is housed in the internal space 17f of the cap 17 so that the negative electrode 14b of the battery 14 is in contact with the closing portion 17d of the cap 17. The housing 15 is housed in the internal space 17f of the cap 17 so that the substrate side opening 17c of the housing 15 is located on the substrate B side.

The elastic body 18 is disposed between the cap 17 and the anode 11. Specifically, the elastic body 18 is disposed between the positive electrode 14a of the battery 14 and the anode current conductor 19. The elastic body 18 is, for example, a compression spring, and elastically supports the cap 17 from below via the battery 14. The elastic body 18 is freely compressively deformed by pressing the cap 17 toward the anode 11 until the end surface 17b of the cap 17 comes into contact with the substrate B. The material of the elastic body 18 is a conductive material, and the anode 11 and the anode current conductor 19 are electrically connected to the positive electrode 14a of the battery 14 via the elastic body 18.

The mounting member 24 is made of a hollow insulating material, and the electrolyte membrane 13 is attached to its inner wall surface. The mounting member 24 is detachable from the housing 15, and is screwed into the housing 15, for example, with a screw. When the mounting member 24 is attached to the housing 15, the electrolyte membrane 13 covers the lower opening 15a of the housing 15 from below.

The insulating cover 20 covers the outside of the cap 17 and is made of an insulating material. As shown in FIG. 2, the insulating cover 20 is formed so that when the end face 17b of the cap 17 is in contact with the surface B1 of the substrate B, the insulating cover 20 is spaced apart from the surface B1 of the substrate B.

As described above, according to the film forming apparatus 1 of this embodiment, when the cap 17 is pressed downward with the electrolyte membrane 13 in contact with the substrate B, the elastic body 18 is compressed and deformed, and the anode 11 and the anode current conductor 19 are urged downward by the elastic body 18. As a result, the anode 11 and the anode current conductor 19 slide downward toward the electrolyte membrane 13 within the container 15. As a result, the liquid pressure of the electrolyte solution L contained between the anode 11 and the electrolyte membrane 13 increases, and the electrolyte membrane 13 can be made to conform to the surface B1 of the substrate B. When the cap 17 is further pressed downward, the end surface 17b of the cap 17 comes into contact with the surface B1 of the substrate B. As a result, the substrate B is conducted to the negative electrode 14b of the battery 14 via the cap 17, and a voltage is applied between the anode 11 and the substrate B. In this way, simply by pushing the cap 17 downward, the electrolyte membrane 13 conforms to the surface B1 of the substrate B, and deposition of the metal film can begin.

In the above embodiment, the electrolyte L is directly stored in the storage space 15c of the storage body 15. However, a porous body (not shown) impregnated with the electrolyte L may be stored in the storage space 15c of the storage body 15. The material of the porous body may be, for example, a polymer with water absorption function or a resin with ion exchange function. The porous body may also be a so-called sponge (plastic foam). The porous body may be made of a material that has compressive deformation and flexibility, but may also be made of a metal material that is corrosion-resistant to the electrolyte L.

When the cap 17 is pressed downward while the porous body made of a material having compressive deformation and flexibility is housed in the housing 15, the elastic body 18 is compressed and deformed, and the anode 11 applies a force to the porous body toward the electrolyte membrane 13. As a result, the porous body is compressed and deformed to conform to the electrolyte membrane 13, so that the electrolyte membrane 13 can be uniformly pressurized by the porous body. As a result, the electrolyte membrane 13 can be made to conform uniformly to the surface B1 of the substrate B. In addition, leakage of the electrolyte solution L can be reduced by impregnating the porous body housed in the housing space 15c of the housing 15 with the electrolyte solution L.

The porous body may or may not be constrained by the container 15 while contained in the container 15. If the porous body is constrained by the container 15, the weight of the electrolyte solution L is prevented from being applied to the electrolyte membrane 13 when the film forming device 1 is separated from the substrate B, thereby suppressing deformation of the electrolyte membrane 13.

Next, a film forming method using the film forming apparatus 1 according to this embodiment will be described. FIG. 3 is a flow chart explaining a method for forming a metal film using the film forming apparatus 1 of FIG. 1. All steps of this film forming method are performed manually. This flow chart explains the case where the electrolyte L is directly (i.e., without using a porous body) contained in the storage space 15c of the storage body 15.

First, in S100, the various components constituting the film forming apparatus 1 are attached. As an example, an insulating cover 20 is attached to the cap 17, and the anode 11 and anode current conductor 19 are housed in the housing 15. Then, the battery 14, the elastic body 18, and the housing 15 are placed in the internal space 17f of the cap 17. Specifically, the negative electrode 14b of the battery 14 is attached to the closing portion 17d of the cap 17, the positive electrode 14a of the battery 14 is attached to one end of the elastic body 18, and the anode current conductor 19 is attached to the other end of the elastic body 18.

Next, in S200, with the lower opening 15a of the container 15 facing upward, the electrolyte L is replenished into the storage space 15c of the container 15 from the side of the lower opening 15a of the container 15.

Then, in S300, the mounting member 24 to which the electrolyte membrane 13 is attached is screwed into the housing 15. As a result, the lower opening 15a of the housing 15 is covered by the electrolyte membrane 13.

Next, in S400, surface B1 of substrate B is pretreated. In this process, foreign matter and passive film adhering to surface B1 of substrate B are removed in order to ensure the electrical conductivity of surface B1 of substrate B.

In S500, the substrate B is placed in the film forming apparatus 1. Specifically, as shown in FIG. 1, the surface B1 of the substrate B is brought into contact with the electrolyte membrane 13.

In S600, as shown in FIG. 2, a predetermined force F is applied to the film forming device 1 to press the film forming device 1 against the substrate B. Specifically, with the electrolyte membrane 13 in contact with the substrate B, the cap 17 is pressed downward with a predetermined force F. This compresses and deforms the elastic body 18, and the anode 11 is urged downward by the elastic body 18, and the anode 11 slides downward toward the electrolyte membrane 13 within the container 15. As a result, the liquid pressure of the electrolyte solution L contained between the anode 11 and the electrolyte membrane 13 increases, and the electrolyte membrane 13 can be made to conform to the surface B1 of the substrate B. When the cap 17 is further pressed downward, the end surface 17b of the cap 17 comes into contact with the surface B1 of the substrate B, and the substrate B is conductive to the negative electrode 14b of the battery 14 through the cap 17. As a result, a voltage is applied between the anode 11 and the substrate B, and the formation of the metal film is started.

In S700, a force F is continuously applied to the film forming device 1 to keep the end surface 17b of the cap 17 in contact with the surface B1 of the substrate B, and a metal film is formed.

In S800, the force F applied to the film forming apparatus 1 is removed, and the end surface 17b of the cap 17 is separated from the surface B1 of the substrate B by the restoring force of the elastic body 18.

In S900, the residue on the surface B1 of the substrate B is removed, for example by wiping, and the deposition of the metal coating is completed.

Next, a film forming apparatus 1A according to another embodiment will be described. FIG. 4 is a schematic cross-sectional view of a metal film forming apparatus 1A according to another embodiment of the present invention, showing a state in which the cap 17 is separated from the substrate B. The film forming apparatus 1A according to the other embodiment differs from the film forming apparatus 1 according to the above embodiment in the configuration of the power supply unit, the configuration of the anode current conductor 19, the configuration of the cap 17, and the configuration of the insulating cover 20. Below, configurations having the same or similar functions as the film forming apparatus 1 according to the above embodiment will be given the same reference numerals and their description will be omitted, and the different parts will be described.

The film forming apparatus 1A according to this embodiment applies a voltage between the anode 11 and the substrate B using an external power supply (power supply unit) not shown. As an example, the positive electrode of the external power supply is connected to the handle 19b of the anode current conductor 19 via the positive electrode side conductor 14c. The handle 19b of the anode current conductor 19 is a rod-shaped portion that extends upward from the anode contact portion 19a that is in direct contact with the anode 11. As an example, the negative electrode of the external power supply is connected to the sheath portion 17g of the cap 17 described below via the negative electrode side conductor 14d.

The cap 17 has a hollow cylindrical sheath 17g that extends upward from the closing portion 17d. The inside of the sheath 17g and the internal space 17f of the cap 17 are in communication with each other via a through space that passes vertically through the closing portion 17d of the cap 17. A hollow cylindrical insulating sleeve 22 is attached to the inner wall surface that separates the inside of the sheath 17g from the through space of the closing portion 17d, and the handle 19b of the anode current conductor 19 can slide freely within the insulating sleeve 22.

An insulating sheet 23 is attached to the blocking portion 17d on the side of the internal space 17f of the cap 17, and the elastic body 18 surrounds the handle portion 19b of the anode current conductor 19 and is positioned between the insulating sheet 23 and the anode contact portion 19a.

As an example, the insulating cover 20 is attached to the outside of the cap 17 so as to be in direct contact with the side wall portion 17e, the closing portion 17d, and the sheath portion 17g of the cap 17. The insulating cover 20 covers the sheath portion 17g and the closing portion 17d of the cap 17 so that the sheath portion 17g and the closing portion 17d of the cap 17 are not exposed to the outside. The insulating cover 20 is freely movable in the vertical direction together with the cap 17.

In the film forming apparatus 1A according to this embodiment, a voltage is applied to the anode 11 and the substrate B using an external power source, so film formation can be performed at a higher output and for a longer period of time compared to the film forming apparatus 1 according to the above embodiment.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the film forming apparatus 1, 1A according to the above-mentioned embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims. In addition, each configuration may be appropriately and selectively combined to achieve the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above-mentioned embodiments may be appropriately changed depending on the specific embodiment of the present invention.

1, 1A: Film forming device, 11: Anode, 13: Solid electrolyte membrane, 14: Battery (power supply), 15: Container, 15a: Lower opening (opening), 17: Cap, 17a: End, 17b: End face, 18: Elastic body, B: Substrate, B1: Surface, L: Electrolyte

Claims (1)

An anode;
a solid electrolyte membrane disposed between the anode and a substrate;
a power supply unit that applies a voltage between the anode and the substrate, the substrate being a cathode;
an insulating container that covers an opening on the side of the base material with the solid electrolyte membrane, accommodates the anode at a position spaced from the solid electrolyte membrane so as to be slidable in a direction toward the solid electrolyte membrane, and accommodates an electrolytic solution containing metal ions between the solid electrolyte membrane and the anode,
a voltage is applied between the anode and the substrate in a state in which the solid electrolyte membrane is in contact with the substrate, and the metal ions contained inside the solid electrolyte membrane are reduced to form a metal coating derived from the metal ions on a surface of the substrate,
the film forming apparatus includes a conductive cap that covers the container from the anode side, and an elastic body that is disposed between the cap and the anode;
The positive electrode of the power supply unit is connected to the anode,
The negative electrode of the power supply unit is connected to the cap,
an end of the cap is formed to be spaced from the substrate when the solid electrolyte membrane is in contact with the substrate, and the elastic body is freely compressively deformed by pressing the cap toward the anode until the end face of the cap comes into contact with the substrate.

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