JP7616038B2 - Metal film forming apparatus and method - Google Patents

Description

The present invention relates to a film forming apparatus for forming a metal film on the surface of a substrate, and a film forming method thereof.

Conventionally, a metal coating has been formed by depositing a metal on the surface of a substrate (for example, see Patent Document 1). Patent Document 1 describes a metal coating forming device that includes an anode, a solid electrolyte membrane (hereinafter also referred to as electrolyte membrane) disposed between the anode and the substrate serving as the cathode, a power supply unit that applies a voltage between the anode and the substrate, and a container that contains an electrolyte solution containing metal ions between the anode and the electrolyte membrane.

In this film forming device, with the electrolyte membrane in contact with the substrate, a voltage is applied between the anode and the substrate using a power supply. This causes the metal ions contained in the electrolyte membrane to migrate to the surface of the substrate in contact with the electrolyte membrane and are reduced on the surface of the substrate. As a result, the metal is deposited on the surface of the substrate, forming a metal film.

JP 2016-169399 A

In the above-mentioned film forming device, the metal film may be formed using a heated electrolyte to increase the film formation speed. In this case, the heated electrolyte is contained in a container, and the heat of the electrolyte is transferred to the container and the electrolyte membrane, causing the container and the electrolyte membrane to become heated.

After the formation of the metal film is completed, the electrolyte in the container may be replaced with the atmosphere. However, at this time, the electrolyte attached to the electrolyte membrane evaporates into the atmosphere in the container due to the heat of the electrolyte membrane. In particular, the heat stored in the container continues to be transferred to the electrolyte membrane, which promotes the continued evaporation of the electrolyte solution and causes the electrolyte membrane to become dry. This drying may cause plating components (such as copper sulfate) to precipitate inside or on the surface of the electrolyte membrane. When a voltage is applied between the anode and the substrate using a power supply unit while the plating components are precipitated on the electrolyte membrane, pits and pinholes may occur in the formed metal film.

The present invention has been made in consideration of these points, and its purpose is to provide a metal film forming device and a film forming method that improves the quality of the film by suppressing the evaporation of the electrolyte solution adhering to the electrolyte membrane.

In view of the above problem, the metal film forming apparatus according to the present invention includes 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, a container that contains the anode and an electrolyte solution containing metal ions and has an opening on the substrate side covered with the solid electrolyte membrane, and a voltage is applied between the anode and the substrate while the solid electrolyte membrane is in contact with the substrate, thereby reducing the metal ions contained inside the solid electrolyte membrane to form a metal film derived from the metal ions on the surface of the substrate. The metal film forming apparatus further includes a heating device that heats the electrolyte solution contained in the container so that the temperature of the electrolyte solution is a predetermined temperature, and a gas-liquid exchanger that exchanges the electrolyte solution contained in the container with air, and the container is characterized in that a heat insulating space that insulates the heat from the container to the solid electrolyte membrane is formed along the periphery of the opening at the position where the solid electrolyte membrane is attached.

In the film forming apparatus according to the present invention, the electrolyte heated to a predetermined temperature by the heating device is contained in the container, so that the heat of the electrolyte is transferred to the electrolyte membrane and the container, and these are heated. For example, after the film formation is completed, the electrolyte contained in the container is replaced with air by the gas-liquid exchange device in the film forming apparatus. When the electrolyte in the container is replaced with air, even if the heat transferred from the electrolyte is stored in the container, the heat from the container to the electrolyte membrane can be insulated by the above-mentioned insulating space, so that the electrolyte membrane is not easily heated by the heat from the container. In particular, the heat of the electrolyte is transferred to the entire wall surface of the container space, but since the insulating space is formed along the periphery of the opening, it is possible to suppress the heat from being transferred locally from a part of the periphery to the electrolyte membrane. Therefore, the electrolyte membrane in contact with the periphery can be uniformly insulated. Therefore, the electrolyte attached to the electrolyte membrane is suppressed from evaporating into the atmosphere, etc., and the electrolyte membrane is less likely to dry out. Therefore, the precipitation of metal components inside and on the surface of the electrolyte membrane is suppressed. This prevents pits and pinholes from appearing in the deposited metal film, improving the quality of the film.

In a preferred embodiment, the heat insulating space is the internal space of a groove provided in the end face of the container that forms the opening, and the solid electrolyte membrane is attached to the end face of the container to seal the heat insulating space.

According to this aspect, the electrolyte membrane is attached to the end face of the housing, sealing the insulating space. This allows the electrolyte membrane to be stably attached to the housing. In this way, the stability of the electrolyte membrane attachment to the housing can be improved, and the insulation from the housing to the electrolyte membrane can be improved.

In a preferred embodiment, the heat insulating space is depressurized to a pressure lower than atmospheric pressure. A depressurized space has higher insulation properties than a non-depressurized space, and the heat insulating space can further suppress the transfer of heat from the container to the electrolyte membrane.

In a preferred embodiment, the film forming apparatus includes a base that holds the substrate below the container so that the substrate faces the solid electrolyte membrane, a lifting device that raises and lowers at least one of the container and the base so that the solid electrolyte membrane and the substrate can be brought into contact with and separated from each other, and a control device that controls the operation of the lifting device and the gas-liquid exchange device, and the control device controls the operation of the gas-liquid exchange device to replace the electrolyte solution inside the container with the atmosphere, and then controls the operation of the lifting device to separate the solid electrolyte membrane from the substrate.

According to this embodiment, the electrolyte membrane is separated from the substrate after the electrolyte solution inside the container is replaced with the atmosphere. Therefore, when the container is separated from the base, the electrolyte membrane is unlikely to be deformed due to the weight of the electrolyte solution. This makes it possible to avoid deformation of the electrolyte membrane and to prevent the electrolyte membrane from drying out when the atmosphere is introduced into the container. This allows for more uniform membrane formation, further improving the quality of the membrane formation.

The present application further discloses a deposition method that can effectively deposit a metal coating. The method for forming a metal film according to the present invention is a method for forming a metal film derived from the metal ions on the surface of a substrate by applying a voltage between an anode and the substrate, which is a cathode, in a state where a solid electrolyte film that has been in contact with an electrolytic solution containing metal ions is in contact with the substrate, and reducing the metal ions contained inside the solid electrolyte film. The method includes the steps of: bringing the solid electrolyte film covering an opening formed in a container into contact with the substrate; applying a voltage between the anode and the substrate in a state where the solid electrolyte film is in contact with the substrate and the electrolytic solution heated to a predetermined temperature is contained in the container, thereby forming the metal film; and replacing the electrolytic solution contained in the container with air after the metal film is formed. The container is characterized in that a heat insulating space that insulates the heat from the container to the solid electrolyte film is formed along the periphery of the opening at the position where the solid electrolyte film is attached.

In the film forming method according to the present invention, since the electrolyte heated to a predetermined temperature is contained in the container before the metal film is formed, the heat of the electrolyte is transferred to the electrolyte membrane and the container, which are heated. After the metal film is formed, the electrolyte contained in the container is replaced with the atmosphere. Even if the electrolyte is further supplied to the container after the electrolyte is replaced with the atmosphere and a plurality of metal films are formed by the above-mentioned series of steps, the heat directed from the container to the electrolyte membrane in a state in which the atmosphere is introduced into the container can be insulated by the above-mentioned insulating space. Therefore, the electrolyte membrane is not easily heated by the heat from the container. In particular, while the above-mentioned series of steps are repeated, the heat of the electrolyte is stored on the entire wall surface of the container space, but since the insulating space is formed along the peripheral portion of the opening, it is possible to suppress the heat being transferred locally from, for example, a part of the peripheral portion to the electrolyte membrane. Therefore, the electrolyte membrane in contact with the peripheral portion can be uniformly insulated. Therefore, the electrolyte attached to the electrolyte membrane is suppressed from evaporating into the atmosphere, etc., and the electrolyte membrane is less likely to dry out. This suppresses the precipitation of metal components inside and on the surface of the electrolyte membrane. This prevents pits and pinholes from appearing in the formed metal film, improving the quality of the film.

In a preferred embodiment, the heat insulating space is the internal space of a groove provided in the end face of the container that forms the opening, and the solid electrolyte membrane is attached to the end face of the container to seal the heat insulating space.

According to this aspect, the electrolyte membrane is attached to the end face of the housing, sealing the insulating space. This allows the electrolyte membrane to be stably attached to the housing. In this way, the stability of the electrolyte membrane attachment to the housing can be improved, and the insulation from the housing to the electrolyte membrane can be improved.

In a preferred embodiment, the heat insulating space is depressurized to a pressure lower than atmospheric pressure. A depressurized space has higher insulation properties than a non-depressurized space, and the heat insulating space can further suppress the transfer of heat from the container to the electrolyte membrane.

In a preferred embodiment, in the step of contacting the substrate, the substrate is disposed below the container so that the substrate faces the solid electrolyte membrane, and in the step of replacing the electrolyte with the atmosphere, the electrolyte is replaced with the atmosphere while the substrate is in contact with the solid electrolyte membrane, and after the electrolyte is replaced with the atmosphere, the solid electrolyte membrane is separated from the surface of the substrate.

According to this embodiment, the electrolyte membrane is separated from the substrate after the electrolyte solution inside the container is replaced with the atmosphere. Therefore, when the container is separated from the base, the solid electrolyte membrane is unlikely to be deformed due to the weight of the electrolyte solution. This makes it possible to avoid deformation of the electrolyte membrane and to prevent the electrolyte membrane from drying out when the atmosphere is introduced into the container. This allows for more uniform membrane formation, further improving the quality of the membrane formation.

According to the present invention, the evaporation of the electrolyte attached to the solid electrolyte film can be suppressed, thereby improving the quality of the film formation.

1 is a schematic cross-sectional view of a metal film forming apparatus according to an embodiment of the present invention. 2 shows a state in which an electrolyte solution has been injected into the film forming apparatus of FIG. 1. 2 is a view showing a container as viewed from the base side in the film forming apparatus of FIG. 1; FIG. 2 is a flowchart illustrating a film forming method using the film forming apparatus of FIG. 1 . FIG. 1 is a schematic cross-sectional view showing a first modified example of a film forming apparatus according to an embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a second modified example of a film forming apparatus according to an embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing a third modified example of the film forming apparatus according to the embodiment of the present invention.

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 forming apparatus 1A according to an embodiment of the present invention. Figure 2 shows the state in which an electrolyte L has been poured into the film forming apparatus 1A of Figure 1. Figure 3 shows the container 15 of the film forming apparatus 1A of Figure 1 as viewed from the side of the base 20.

As shown in Figures 1 to 3, the film forming apparatus 1A 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, and a power supply unit 14 that applies a voltage between the anode 11 and the substrate B with the substrate B serving as a cathode. The film forming apparatus 1A further includes a container 15. The container 15 contains the anode 11 and an electrolyte solution L containing metal ions, and an opening 15h of the container 15 is covered with the solid electrolyte membrane 13.

As shown in FIG. 2, the film forming apparatus 1A 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 F derived from the metal ions on the surface B1 of the substrate B. Note that in this embodiment, for convenience of explanation, the positional relationship of the components of the film forming apparatus 1A 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 the metal film F can be formed on the surface B1 of the substrate B, this positional relationship is not limited, and for example, the film forming apparatus 1A 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 may be made of a metal material such as copper, silver, gold, nickel, aluminum, or iron, or may be made of a resin, ceramic, or the like, with a metal layer such as copper coated on the surface. The film forming apparatus 1A further includes a base 20 that holds the substrate B below the container 15 so that the substrate B faces the electrolyte membrane 13. The substrate B is electrically connected to the negative electrode of the power supply unit 14.

The anode 11 has a shape corresponding to the film formation region of the substrate B. The film formation 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 coating F. The anode 11 may be non-porous (for example, non-porous) or porous. The anode 11 may be block-shaped or flat, or may be a metal ball. Examples of the material of the anode 11 include copper, nickel, gold, and silver. The anode 11 may be soluble in the electrolyte L. In other words, the anode 11 may be dissolved by applying a voltage using the power supply unit 14. However, if the film is formed only using the electrolyte L containing metal ions, the anode 11 does not need to be dissolved. The anode 11 is electrically connected to the positive electrode of the power supply unit 14.

The electrolyte L is a liquid that contains the metal of the metal film F to be formed in an ionic state, and examples of such metals include copper, nickel, gold, 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 are reduced in the substrate B when a voltage is applied by the power supply unit 14, and the 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. As shown in Figures 1 and 2, the electrolyte membrane 13 includes a membrane center portion 13a facing the membrane formation region of the substrate B and a membrane outer portion 13b located outside the membrane center portion 13a when attached to the container 15.

As shown in FIG. 1 and FIG. 3, the container 15 is a housing with an opening 15h formed on the side of the base 20. The container 15 has a central wall 15e corresponding to the bottom of the housing, and a side wall 15f extending from the periphery of the central wall 15e to the side of the base 20. The space surrounded by the central wall 15e and the side wall 15f is a storage space 15d that stores the anode 11 and the electrolyte L. The anode 11 is attached to the central wall 15e, and the tip of the rod 72 of the linear actuator 70 described later is fixed to the central wall 15e. The end surface 15g of the side wall 15f is a frame-shaped end surface that forms the opening 15h that opens to the side of the substrate B, and is the end surface of the container 15 facing the electrolyte membrane 13. The anode 11 and the electrolyte membrane 13 are attached to the container 15 at a distance from each other, and the storage space 15d between them is filled with the electrolyte L. In this way, the container 15 is structured so that the electrolyte L contained in the container space 15d is in direct contact with 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 FIG. 3, in the housing 15, a peripheral portion 15a is formed around the periphery of the opening 15h. The peripheral portion 15a includes a part of the side of the opening 15h on the inside of the side wall portion 15f and a part of the side of the opening 15h on the end face 15g. A groove portion 40 is formed on the end face 15g of the side wall portion 15f along the peripheral portion 15a of the opening 15h. The groove portion 40 is formed so as to go around the opening 15h. The groove portion 40 may be formed continuously (FIG. 3) or intermittently. The groove portion 40 is formed recessed from the end face 15g in the opposite direction to the electrolyte membrane 13. Specifically, the groove portion 40 includes a bottom wall surface 44 facing the electrolyte membrane 13 and a pair of side wall surfaces 46 extending from the bottom wall surface 44 toward the electrolyte membrane 13. The internal space 48 of the groove 40 is formed by a bottom wall surface 44 and a pair of side wall surfaces 46. The groove 40 has a groove opening 42 on the side of the electrolyte membrane 13, i.e., the side facing the bottom wall surface 44. The groove 40 can be formed on the end surface 15g of the housing 15, for example, by machining. In this embodiment, the groove 40 is formed on the housing 15, which has mechanical rigidity. For this reason, for example, when the housing 15 abuts against the base 20, the groove 40 does not deform.

The electrolyte membrane 13 is attached to the end face 15g at the membrane outer part 13b, and seals the internal space 48 of the groove 40. That is, the electrolyte membrane 13 covers the opening 15h of the container 15 with the membrane center part 13a, and covers the groove opening 42 of the groove 40 with the membrane outer part 13b. The internal space 48 of the groove 40 is an insulating space that insulates the heat from the container 15 toward the electrolyte membrane 13, and since the electrolyte membrane 13 covers the groove opening 42 of the groove 40, this insulating space is formed at the position where the electrolyte membrane 13 is attached (specifically, the position of the end face 15g). Note that FIGS. 1 and 2 show the groove 40 having a rectangular cross section. However, the cross-sectional shape of the groove 40 is not limited to a rectangle, and for example, the groove 40 may be formed so that a pair of side wall surfaces 46 are separated from each other from the bottom wall surface 44 toward the electrolyte membrane 13, or may be formed so as to approach each other. In this way, the groove 40 forms an internal space 48, which insulates the heat from the housing 15 to the electrolyte membrane 13. In addition, the electrolyte membrane 13 can be stably attached to the end surface 15g of the housing 15.

Preferably, the internal space 48 is depressurized to a pressure lower than atmospheric pressure. This depressurized internal space 48 can further reduce the transfer of heat from the housing 15 to the electrolyte membrane 13.

Note that, if necessary, a sealant may be further provided on the end face 15g along the peripheral portion 15a. The sealant is, for example, a sealing material made of an elastic material such as rubber or resin that deforms when the housing 15 abuts against the base 20. The sealant may be provided, for example, on the side of the end face 15g adjacent to the opening 15h.

The side wall portion 15f of the container 15 is formed with a supply flow path 15b for supplying the electrolyte L to the storage space 15d and a discharge flow path 15c for discharging the electrolyte L from the storage space 15d. Both the supply flow path 15b and the discharge flow path 15c are connected to the storage space 15d, and are formed on either side of the storage space 15d. The supply flow path 15b and the discharge flow path 15c are inclined with respect to the direction in which the side wall portion 15f extends (i.e., the thickness direction of the side wall portion 15f) so as to approach the electrolyte membrane 13 as they proceed from the outer surface of the side wall portion 15f to the inner wall surface that forms the storage space 15d. The supply flow path 15b and the discharge flow path 15c are fluidly connected to a liquid supply pipe 50 and a liquid discharge pipe 52, respectively, which will be described later.

1 and 2, the film forming apparatus 1A includes a linear actuator 70 (lifting device) that lifts and lowers at least one of the container 15 and the base 20 so that the electrolyte membrane 13 and the substrate B can be brought into contact with and separated from each other. In this embodiment, the base 20 is fixed, and the container 15 is lifted and lowered by the linear actuator 70. The linear actuator 70 is an electric actuator, and includes, for example, a guide 71 to which a motor (not shown) is attached, and a rod 72 that moves linearly relative to the guide 71. The rod 72 converts the rotational motion of the motor into linear motion, for example, by a ball screw or the like (not shown). The linear actuator 70 lifts and lowers the container 15 relative to the base 20, making it possible to bring the electrolyte membrane 13 into contact with and separate from the substrate B. The linear actuator 70 may be provided at the bottom of the base 20. In this case, the base 20 is lifted and lowered to bring the substrate B into contact with and separate from the electrolyte membrane 13.

Next, a mechanism for circulating the electrolyte L in the film forming apparatus 1A will be described. As shown in FIG. 1, the film forming apparatus 1A is connected to a container 15 and includes a liquid tank T for storing the electrolyte L to be supplied to the container 15. The electrolyte L in the liquid tank T is sucked by a pump P, which will be described later, and is supplied to the container 15 through a liquid supply pipe 50. The electrolyte L used during film formation is discharged from the container 15 to the liquid tank T through a liquid discharge pipe 52. A liquid level sensor 92 is attached to the inner surface of the liquid tank T. The liquid level sensor 92 measures the height of the electrolyte L inside the liquid tank T as a continuous value (for example, 0% to 100%) and transmits the measured value to a control device 90, which will be described later. Examples of the liquid level sensor 92 include an ultrasonic type and a pressure type, but are not limited to these as long as it can measure the height of the electrolyte L in the liquid tank T.

The film forming apparatus 1A also includes a heating device 30 that heats the electrolyte L contained in the container 15 so that the electrolyte L is heated to a predetermined temperature. The heating device 30 heats the electrolyte L to about 30°C to 90°C. The heating device 30 may have a heat generating portion that generates heat by resistance heating, for example. The heating device 30 may have a heat generating portion immersed in the electrolyte L and directly heat the electrolyte L, or may have a heat generating portion attached to the outside of the liquid tank T and heat the electrolyte L via the liquid tank T. The heating device 30 may also be attached to the liquid supply pipe 50 or may be built into the container 15. For example, the heating device 30 may be built into the side wall portion 15f of the container 15.

The liquid supply pipe 50 is provided with a pump P that supplies the electrolyte L from the liquid tank T to the container 15. In this embodiment, the pump P is configured to be capable of rotating in both forward and reverse directions. When the pump P rotates forward, the electrolyte L is sucked from the liquid tank T into the liquid supply pipe 50, and the electrolyte L is pumped into the container space 15d of the container 15. On the other hand, when the pump P rotates reversely, the electrolyte L is returned from the container 15 to the liquid tank T through the liquid supply pipe 50. The replacement of the electrolyte L in the container 15 with the atmosphere using the pump P will be described later.

The liquid discharge pipe 52 is provided with a three-way valve 60 that switches the flow direction of the electrolyte L. Specifically, the three-way valve 60 switches between the flow direction D1 of the electrolyte L from the container 15 to the liquid tank T through the liquid discharge pipe 52 and the flow direction D2 of the atmosphere from the outside to the container 15 through the air inlet pipe 62 and the liquid discharge pipe 52 (see FIG. 1). In addition, a pressure adjustment valve 58 is interposed in the liquid discharge pipe 52 downstream of the three-way valve 60 in the flow direction D1, which prevents the pressure (liquid pressure) of the electrolyte L contained in the container space 15d from exceeding a predetermined pressure. By continuously rotating the pump P in the forward direction, the electrolyte L in the liquid tank T is continuously supplied to the container space 15d of the container 15, and the electrolyte L in the container space 15d is maintained at a constant pressure by the pressure adjustment valve 58.

Next, a mechanism for exchanging the electrolyte L contained in the container 15 with the atmosphere will be described. The film forming apparatus 1A is equipped with a gas-liquid exchanger 80 that exchanges the electrolyte L contained in the container 15 with the atmosphere. The gas-liquid exchanger 80 returns the electrolyte L contained in the container 15 to the liquid tank T by exchanging the electrolyte L in the storage space 15d of the container 15 with the atmosphere. The gas-liquid exchanger 80 may include a pump P and a three-way valve 60. In this embodiment, the case where the pump P is a component of the gas-liquid exchanger 80 will be described. By rotating the pump P in the reverse direction, the electrolyte L is sucked from the container 15 to the liquid supply pipe 50, and the electrolyte L is pumped to the liquid tank T. At this time, the three-way valve 60 is switched to form an air flow direction D2 from the outside toward the container 15, so that as the pump P continues to rotate in reverse, air is introduced into the container space 15d of the container 15 through the air inlet pipe 62, the liquid outlet pipe 52, and the outlet flow path 15c. In this way, the gas-liquid exchanger 80 replaces the electrolyte L contained in the container space 15d with the atmosphere by rotating the pump P in reverse and switching the three-way valve 60.

1 and 2, the film forming apparatus 1A includes a control device 90 that controls the operation of the linear actuator 70 and the gas-liquid exchanger 80. The control device 90 comprehensively controls the operation of the film forming apparatus 1A, and can transmit and receive information between each component of the film forming apparatus 1A by wire or wirelessly. For example, the control device 90 may transmit and receive a signal related to the height of the electrolyte L transmitted from the liquid level sensor 92, a signal related to the stroke amount of the rod 72 relative to the guide 71, and information related to the rotation speed and rotation direction of the pump P. One of the functions of the control device 90 is to control the operation of the gas-liquid exchanger 80. The control device 90 replaces the electrolyte L in the container 15 with the atmosphere by controlling the operation of the gas-liquid exchanger 80. Specifically, the control device 90 controls the rotation direction of the pump P so as to rotate it in the reverse direction, and controls the switching of the three-way valve 60 so as to introduce the atmosphere into the container space 15d.

In addition, the control device 90 has a function of controlling the operation of the linear actuator 70 as one of its functions. After replacing the electrolyte solution L with atmospheric air inside the container 15, the control device 90 separates the electrolyte membrane 13 from the substrate B by controlling the operation of the linear actuator 70. Specifically, the control device 90 controls the movement direction of the rod 72 of the linear actuator 70 so as to separate the container 15 from the base 20. In this way, after the electrolyte solution L inside the container 15 is replaced with atmospheric air, the control device 90 separates the electrolyte membrane 13 from the substrate B. Therefore, when the container 15 is separated from the base 20, the electrolyte membrane 13 is unlikely to be deformed due to the weight of the electrolyte solution L. Therefore, it is possible to avoid deformation of the electrolyte membrane 13 and to avoid drying of the electrolyte membrane 13 when atmospheric air is introduced into the container 15. Therefore, a more uniform film can be formed, and the film formation quality can be further improved. Here, one function of the control device 90 has been described, but the operation control of the entire film forming apparatus 1A using the control device 90 will be described later. Each step (S100 to S180) included in the film forming method described below is realized by the control device 90 controlling the operation of each component of the film forming apparatus 1A.

In the film forming apparatus 1A according to the present embodiment, the electrolyte L heated to a predetermined temperature by the heating device 30 is contained in the container 15, so that the heat of the electrolyte L is transferred to the electrolyte membrane 13 and the container 15, and these are heated. For example, after the film formation is completed, the electrolyte L contained in the container 15 is replaced with air by the gas-liquid exchange device 80 in the film forming apparatus 1A. When the electrolyte L in the container 15 is replaced with air, even if the heat transferred from the electrolyte L is stored in the container 15, the internal space 48 of the groove portion 40 can insulate the heat from the container 15 to the electrolyte membrane 13, so that the electrolyte membrane 13 is not easily heated by the heat from the container 15. Therefore, the electrolyte L attached to the electrolyte membrane 13 is suppressed from evaporating into the atmosphere, etc., and the electrolyte membrane 13 is less likely to dry out. As a result, the precipitation of metal components inside and on the surface of the electrolyte membrane 13 is suppressed. This prevents pits and pinholes from appearing in the formed metal film F, improving the quality of the film.

In particular, the heat of the electrolyte L is transferred to the entire wall surface of the storage space 15d, but when the groove portion 40 is continuously formed along the peripheral portion 15a of the opening 15h, it is possible to suppress the heat from being transferred locally from a part of the peripheral portion 15a to the electrolyte membrane 13. Therefore, the electrolyte membrane 13 in contact with the peripheral portion 15a can be uniformly insulated.

Next, a film formation method using the film formation apparatus 1A according to this embodiment will be described. FIG. 4 is a flow chart explaining the film formation method using the film formation apparatus 1A of FIG. 1. In the film formation method according to this embodiment, an electrolyte membrane 13, which has been in contact with an electrolytic solution L containing metal ions, is brought into contact with a substrate B, and a voltage is applied between the anode 11 and the substrate B, which acts as a cathode, to reduce the metal ions contained inside the electrolyte membrane 13, thereby forming a metal coating F derived from the metal ions on the surface B1 of the substrate B.

In the film forming method according to the present embodiment, first, the above-mentioned housing 15 is used as a premise before film formation. In the housing 15, a groove 40 is formed along the peripheral portion 15a of the opening 15h at the position where the electrolyte membrane 13 is attached. The internal space 48 of the groove 40 is provided in the end surface 15g of the housing 15 that forms the opening 15h. The electrolyte membrane 13 is attached to this end surface 15g, sealing the internal space 48. The internal space 48 is an insulating space that insulates against heat from the housing 15 to the electrolyte membrane 13. This internal space 48 insulates against heat from the housing 15 to the electrolyte membrane 13. In addition, the electrolyte membrane 13 can be stably attached to the end surface 15g of the housing 15. Preferably, the internal space 48 is depressurized to a pressure lower than atmospheric pressure. This depressurized internal space 48 can further suppress the transfer of heat from the housing 15 to the electrolyte membrane 13.

In this membrane forming method, the steps (S100, S110) of bringing the electrolyte membrane 13 into contact with the substrate B are carried out. In S100, the control device 90 controls a conveying device (not shown) and the like to hold the substrate B on the base 20 arranged below the container 15 so that the substrate B faces the electrolyte membrane 13.

In S110, the control device 90 sends a signal to the linear actuator 70 to extend the rod 72, moving the rod 72 downward relative to the guide 71. This causes the container 15 to descend, bringing the electrolyte membrane 13 into contact with the surface B1 of the substrate B.

Next, in this film formation method, the steps of forming a metal film (S120 to S140) are performed. In this step, a voltage is applied between the anode 11 and the substrate B with the electrolyte membrane 13 in contact with the substrate B and with the electrolyte solution L heated to a predetermined temperature contained in the container 15. As will be described later, in this embodiment, after the step S110 is performed, the electrolyte solution L is contained in the container 15 in the step S130. This is preferable because it is possible to avoid deformation of the electrolyte membrane 13 due to the weight of the electrolyte solution L. However, if deformation of the electrolyte membrane 13 can be suppressed, for example, the steps S120 and S130 may be performed, and then the step S110 may be performed.

In S120, the control device 90 transmits a predetermined valve switching signal to the three-way valve 60, and switches the three-way valve 60 so as to form a flow direction D1 of the electrolyte L. As a result, the electrolyte L can flow from the liquid tank T to the container 15.

In S130, the control device 90 transmits a predetermined drive signal to the pump P, and rotates the pump P in the forward direction so as to accommodate the electrolyte L heated to a predetermined temperature from the liquid tank T that stores the electrolyte L into the accommodation space 15d of the accommodation body 15. As a result, the electrolyte L is accommodated in the accommodation body 15 through the liquid supply pipe 50. At this time, by continuously rotating the pump P in the forward direction, the electrolyte L is continuously supplied to the accommodation body 15, and the electrolyte L inside the accommodation body 15 is maintained at a constant pressure by the pressure adjustment valve 58.

In S140, the control device 90 applies a voltage between the anode 11 and the substrate B for a certain period of time by controlling the power supply unit 14 while the electrolyte membrane 13 is in contact with the surface B1 of the substrate B, thereby forming a metal film F. As a result, the metal ions contained in the solid electrolyte membrane 13 move to the substrate B and are reduced on the surface B1. As a result, metal is precipitated on the surface B1 of the substrate B, and a metal film F with a certain thickness is formed on the surface B1 of the substrate B.

Next, in this film forming method, after the metal film F is formed, the process (S150, S160) of replacing the electrolyte L contained in the container 15 with air is performed. In S150, the electrolyte L is replaced with air while the substrate B is in contact with the electrolyte membrane 13. The control device 90 transmits a predetermined drive signal to the pump P so that the pump P rotates in the reverse direction, and receives a signal from the liquid level sensor 92 regarding the height of the electrolyte L in the liquid tank T. The control device 90 continues to rotate the pump P in the reverse direction until all of the electrolyte L is collected in the liquid tank T (until it is determined that the height of the electrolyte L in the liquid tank T has reached a predetermined height). Next, in S160, the control device 90 transmits a predetermined valve switching signal to the three-way valve 60 for a certain period of time, and switches the three-way valve 60 to form the air flow direction D2. The control device 90 continues switching the three-way valve 60 until the amount of air being introduced (amount of intake air per unit time x time) becomes the capacity of the storage space 15d of the storage body 15.

In this film forming method, after replacing the electrolyte solution L with the atmosphere (S150, S160), the electrolyte membrane 13 is separated from the surface B1 of the substrate B (S170). The control device 90 sends a signal to the linear actuator 70 to return the rod 72. As a result, the rod 72 moves upward relative to the guide 71, and the container 15 rises. In this way, after the electrolyte solution L inside the container 15 is replaced with the atmosphere, the electrolyte membrane 13 is separated from the substrate B, so that when the container 15 is separated from the base 20, the electrolyte membrane 13 is unlikely to be deformed due to the weight of the electrolyte solution L. Therefore, it is possible to avoid deformation of the electrolyte membrane 13 and to avoid drying of the electrolyte membrane 13 when the atmosphere is introduced into the container 15. Therefore, a more uniform film can be formed, and the film formation quality can be further improved.

Finally, in this film formation method, a process (S180) is carried out to remove the substrate B from the base 20. The control device 90 controls a transport device (not shown) and the like to remove the substrate B from the base 20. In this manner, this film formation method ends, and the series of controls of the film formation apparatus 1A using the control device 90 returns to the start. Note that the above film formation method does not require all steps to be performed by the control device 90, and at least some of the steps may be performed manually.

In the film forming method according to the present embodiment, since the electrolyte L heated to a predetermined temperature is contained in the container 15 before the metal film F is formed, the heat of the electrolyte L is transferred to the electrolyte membrane 13 and the container 15, which are heated. After the metal film F is formed, the electrolyte L contained in the container 15 is replaced with the atmosphere. Even if the electrolyte L is replaced with the atmosphere and the electrolyte L is further supplied to the container 15 and multiple metal films F are formed by the above-mentioned series of steps, the heat from the container 15 to the electrolyte membrane 13 when the atmosphere is introduced into the container 15 can be insulated by the internal space 48 of the groove 40. Therefore, the electrolyte membrane 13 is not easily heated by the heat from the container 15.

In particular, while the above-mentioned series of steps are repeated, heat from the electrolyte L is likely to accumulate on the entire wall surface of the storage space 15d. However, since the internal space 48 of the groove portion 40 is formed along the peripheral portion 15a of the opening 15h, it is possible to suppress the heat from being transferred locally from a part of the peripheral portion 15a to the electrolyte membrane 13. Therefore, the electrolyte membrane 13 in contact with the peripheral portion 15a can be uniformly insulated. Therefore, the electrolyte solution L attached to the electrolyte membrane 13 is suppressed from evaporating into the atmosphere, etc., and the electrolyte membrane 13 is less likely to dry out. Therefore, the precipitation of metal components inside and on the surface of the electrolyte membrane 13 is suppressed. Therefore, it is possible to avoid the occurrence of pits and pinholes in the formed metal film F, and improve the quality of the film formation.

<Modification 1>
5 is a schematic cross-sectional view showing a first modified example of the film forming apparatus 1A according to the embodiment of the present invention. The film forming apparatus 1B according to the first modified example is different from the film forming apparatus 1A according to the above embodiment in the number of grooves 40, i.e., the number of internal spaces 48. Hereinafter, the same reference numerals as those in the film forming apparatus 1A according to the above embodiment are used to designate configurations having the same or similar functions as those in the film forming apparatus 1A according to the above embodiment, and the description thereof is omitted, and the different parts are described. Note that, like the film forming apparatus 1A, the film forming apparatus 1B is provided with other components such as a mechanism for circulating the electrolytic solution L (liquid tank T, pump P, etc.), a mechanism for raising and lowering the container 15 (linear actuator 70), and a control device 90.

As shown in FIG. 5, a plurality of grooves 40 are formed on the end surface 15g of the housing 15. The grooves 40 form a plurality of internal spaces 48 on the end surface 15g of the side wall portion 15f. The grooves 40 extend at intervals from each other so as to surround the opening 15h. Therefore, the electrolyte membrane 13 can be attached to the end surface 15g in a larger number of portions than when a single groove 40 is formed. In this way, the plurality of grooves 40 are formed at intervals from each other so as to surround the opening 15h, so that the number of attachment positions of the electrolyte membrane 13 in the housing 15 can be increased. Therefore, the electrolyte membrane 13 can be stably attached to the housing 15.

<Modification 2>
6 is a schematic cross-sectional view showing a modified example 2 of the film forming apparatus 1A according to the embodiment of the present invention. The film forming apparatus 1C according to the modified example 2 is different from the film forming apparatus 1A according to the embodiment in that a heat insulating material 100 is accommodated in the groove portion 40. Hereinafter, the same reference numerals as those in the film forming apparatus 1A according to the embodiment are used to designate components having the same or similar functions as those in the film forming apparatus 1A according to the embodiment, and the description thereof is omitted, and the different parts are described. Note that, like the film forming apparatus 1A, the film forming apparatus 1C includes other components such as a mechanism for circulating the electrolytic solution L (liquid tank T, pump P, etc.), a mechanism for raising and lowering the container 15 (linear actuator 70), and a control device 90.

As shown in FIG. 6, the film forming apparatus 1C according to the second modification includes a heat insulating material 100 accommodated in the internal space 48 of the groove 40. Examples of the heat insulating material 100 include a foam-based heat insulating material, a fiber-based heat insulating material, and an aerogel. The heat insulating material 100 may have a shape corresponding to the groove 40 and may be accommodated so as to fill the entire internal space 48. The heat insulating material 100 may have a shape different from the groove 40 and may be accommodated with a gap between it and the groove 40. The heat insulating material 100 may be compressed inside the groove 40, or may not be compressed (i.e., non-compressed). Although not shown in FIG. 6, a seal member may be disposed between the membrane outer side portion 13b of the electrolyte membrane 13 and the end surface 15g of the container 15. The heat insulating material 100 has higher heat insulating properties than the seal member. Specifically, the heat insulating material 100 has higher heat insulating properties against heat directed from the container 15 to the electrolyte membrane 13 than the seal member.

As described above, the film forming apparatus 1C according to the second modified example includes the insulating material 100 housed in the internal space 48 of the groove portion 40, and therefore the transfer of heat from the container 15 to the electrolyte membrane 13 can be further suppressed.

<Modification 3>
7 is a schematic cross-sectional view of a metal film forming apparatus 1D according to a modified example 3 of the present invention. The film forming apparatus 1D according to the modified example 3 is different from the film forming apparatus 1A according to the embodiment in the configuration of the gas-liquid exchanger 80a. Hereinafter, components having the same or similar functions as the film forming apparatus 1A according to the embodiment will be denoted by the same reference numerals as the film forming apparatus 1A, and the description thereof will be omitted, and the different parts will be described.

In the film forming apparatus 1D according to the third modification, the gas-liquid exchanger 80a includes a three-way valve 60 and a compressor 110. The three-way valve 60 is disposed in the liquid supply pipe 50 between the pump P and the supply flow path 15b of the container 15. The three-way valve 60 switches between the flow direction D3 of the electrolyte L from the liquid tank T to the container 15 through the liquid supply pipe 50 and the flow direction D4 of the compressed air from the compressor 110 to the container 15 through the compressed air introduction pipe 64 and the liquid supply pipe 50 (see FIG. 7). When the three-way valve 60 is switched to form the above-mentioned flow direction D3, the electrolyte L in the liquid tank T is supplied to the container 15 through the liquid supply pipe 50 by rotating the pump P in the forward direction. On the other hand, when the three-way valve 60 is switched to form the flow direction D4, compressed air sent from the compressor 110 is supplied to the container 15 through the compressed air inlet pipe 64 and the liquid supply pipe 50. The compressed air pushes out the electrolyte L contained in the storage space 15d, and the electrolyte L is collected in the liquid tank T through the liquid discharge pipe 52. At this time, the compressed air remains in the storage space 15d, completing the exchange of the electrolyte L with the atmosphere. In this way, the gas-liquid exchange device 80a exchanges the electrolyte L contained in the storage space 15d with the atmosphere by switching the three-way valve 60 and sending compressed air by the compressor 110.

The present invention is illustrated by the following examples.

Using the thermal network method, the temperature of the part corresponding to the membrane outer part 13b of the electrolyte membrane 13 (hereinafter also referred to as part A) and the temperature of the part corresponding to the membrane center part 13a (hereinafter also referred to as part B) were calculated. The calculation conditions were that the parts corresponding to the central wall part 15e and the side wall part 15f of the housing body 15 were set to 70°C, and the air temperature in the housing space 15d of the housing body 15 and the part corresponding to the outside of the housing body 15 was set to 40°C. The temperatures of parts A and B were calculated when this state was maintained for 60 seconds.

In the example, a heat insulating space corresponding to the internal space 48 of the groove 40 was modeled between the portion corresponding to the end face 15g of the side wall 15f and the portion corresponding to the membrane outer portion 13b. In contrast, in the comparative example, a state in which the portion corresponding to the side wall 15f and the portion corresponding to the membrane outer portion 13b are in direct contact was modeled.

<Confirmation of analysis results>

(Results and Discussion)
As shown in Table 1 above, in the embodiment, the temperature of part B is approximately equal to the temperature of the air in the storage space and outside the storage body (40°C), and it is understood that part B is in equilibrium with the temperature of the air around it. Also, the temperature of part A is significantly lower than the temperature of the side wall of the storage body (70°C). Therefore, it is understood that the transfer of heat from the side wall of the storage body to part A is suppressed by the insulating space.

In the comparative example, the temperature of part B was approximately equal to the temperature of the air in the storage space and outside the storage body (40°C), and in this respect, similar results were obtained as in the example. However, the temperature of part A was equal to the temperature of the side wall of the storage body (70°C), and it can be seen that the heat moving from the side wall of the storage body to part A was not insulated and was transferred to part A.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the film forming apparatuses 1A, 1B, 1C, and 1D according to the above-mentioned embodiments, but 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.

For example, in the above embodiment, the case where the insulating space is the groove portion 40, i.e., the opening on the electrolyte membrane 13 side, has been described. However, the insulating space may be a hollow space (a space without an opening) in the side wall portion 15f.

1A, 1B, 1C, 1D: Film forming device, 11: Anode, 13: Solid electrolyte film, 14: Power supply, 15: Container, 15a: Periphery, 15f: Side wall, 15g: End face, 15h: Opening, 40: Groove, 48: Internal space (thermal insulation space), 20: Base, 30: Heating device, 70: Linear actuator (lifting device), 80, 80a: Gas-liquid exchange device, 90: Control device, B: Substrate, B1: Surface, F: Metal film, L: Electrolyte

Claims (8)

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;
a container that contains the anode and an electrolytic solution containing metal ions, and an opening that opens to the side of the base material is covered with the solid electrolyte membrane;
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,
a heating device that heats the electrolyte so that the electrolyte contained in the container has a predetermined temperature;
a gas-liquid exchanger that exchanges the electrolyte contained in the container with air;
a heat insulating space is formed in the container along the periphery of the opening at the position where the solid electrolyte membrane is attached, for insulating heat from the container to the solid electrolyte membrane. The metal coating deposition device according to claim 1, characterized in that the heat insulating space is an internal space of a groove provided in the end face of the container that forms the opening, and the solid electrolyte film is attached to the end face of the container to seal the heat insulating space. The metal coating deposition device according to claim 2, characterized in that the heat insulating space is depressurized to a pressure lower than atmospheric pressure. The film forming apparatus includes:
a base that holds the substrate below the container such that the substrate faces the solid electrolyte membrane;
a lifting device that lifts and lowers at least one of the container and the base so that the solid electrolyte membrane and the base material can be brought into contact with and separated from each other;
A control device that controls the operation of the lifting device and the gas-liquid exchange device,
4. The metal coating deposition apparatus according to claim 1, wherein the control device controls an operation of the gas-liquid exchanger to exchange the electrolyte solution in the container with the atmosphere, and then controls an operation of the lifting device to separate the solid electrolyte film from the substrate. A film formation method for forming a metal coating on a surface of a substrate by applying a voltage between an anode and the substrate, the anode being a cathode, in a state in which a solid electrolyte membrane, which has been in contact with an electrolytic solution containing metal ions, is brought into contact with the substrate, and the metal ions contained inside the solid electrolyte membrane are reduced, the metal coating being derived from the metal ions, comprising:
contacting the solid electrolyte membrane covering the opening formed in the container with the substrate;
a step of applying a voltage between the anode and the substrate while the solid electrolyte membrane is in contact with the substrate and the electrolyte solution heated to a predetermined temperature is contained in the container, thereby forming the metal coating;
and replacing the electrolyte contained in the container with air after the metal coating is formed.
the container has an insulating space formed along the periphery of the opening at the position where the solid electrolyte membrane is attached, for insulating against heat flowing from the container to the solid electrolyte membrane. The method for forming a metal film according to claim 5, characterized in that the heat insulating space is an internal space of a groove provided in the end face of the container that forms the opening, and the solid electrolyte film is attached to the end face of the container to seal the heat insulating space. The method for forming a metal coating according to claim 6, characterized in that the heat insulating space is depressurized to a pressure lower than atmospheric pressure. In the step of contacting the substrate, the substrate is disposed below the container so that the substrate faces the solid electrolyte membrane;
In the step of replacing the electrolytic solution with air, the electrolytic solution is replaced with air while the substrate is in contact with the solid electrolyte membrane;
8. The method for forming a metal coating according to claim 5, further comprising the step of separating the solid electrolyte membrane from the surface of the substrate after the electrolyte solution has been replaced with air.

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