JP2023082465A - Metal film deposition apparatus - Google Patents

Abstract

To provide a metal film deposition apparatus that suppresses the occurrence of appearance defects in a metal film and improves the film deposition quality.SOLUTION: A film deposition apparatus 1A includes an anode 11, a solid electrolyte membrane 13 placed between the anode and a base material B, a power supply 14 which uses the base material as a cathode and applies voltage between the anode and the base material, a housing 15 which houses the anode and an electrolyte L containing metal ions and covers an opening 15a on the side of the base material with a solid electrolyte membrane, a liquid tank T which houses the electrolyte, a liquid supply pipe 50 through which the electrolyte flows from the liquid tank to the housing, a liquid discharge pipe 52 through which the electrolyte flows from the housing to the liquid tank, a supply device P which supplies the electrolyte from the liquid tank to the housing, and a gas-liquid separator 30 which is placed between the supply device and the housing in the liquid supply pipe and separates the gas contained in the electrolyte from the electrolyte.SELECTED DRAWING: Figure 1

Description

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

BACKGROUND ART Conventionally, deposition of metal on the surface of a substrate to form a metal film has been performed (for example, Patent Document 1). Patent Document 1 discloses an anode, a solid electrolyte membrane disposed between the anode and a base material serving as a cathode, a power supply section that applies a voltage between the anode and the base material, and an anode and the solid electrolyte membrane. and a liquid container for containing an electrolytic solution containing metal ions.

In this film forming apparatus, the liquid containing portion is formed with a liquid supply port for supplying the electrolytic solution into the liquid containing portion and a liquid discharge port for discharging the electrolytic solution from the inside of the liquid containing portion. Further, the film forming apparatus includes a circulation mechanism for circulating the electrolytic solution in the liquid container. With such a circulation mechanism, the electrolytic solution is supplied from the liquid supply port to the liquid container, and the electrolytic solution used in the film formation in the liquid container is discharged from the liquid discharge port.

JP 2016-169399 A

However, when a metal film is formed using the film forming apparatus described above, the circulation mechanism is used to circulate the electrolytic solution, so there is a risk that gases such as air may enter the electrolytic solution supplied to the liquid container. rice field. If the metal film is formed while gas is mixed in the electrolytic solution, the gas may locally block the current flow from the anode to the substrate. As a result, pits, pinholes, and the like may occur in the formed metal film, resulting in poor appearance of the metal film.

SUMMARY OF THE INVENTION The present invention has been made in view of these points, and its object is to provide a metal film deposition apparatus that suppresses the occurrence of poor appearance of the metal film and improves the quality of the film. be.

In view of the above problems, a metal film deposition apparatus according to the present invention includes an anode, a solid electrolyte film disposed between the anode and a substrate, and the anode and the substrate using the substrate as a cathode. a power supply unit that applies a voltage between, a container that contains the anode and an electrolytic solution containing metal ions, and an opening that opens toward the base material is covered with the solid electrolyte membrane; connecting a liquid tank containing a liquid to the liquid tank and the container, connecting a liquid supply pipe through which the electrolytic solution flows from the liquid tank to the container, and connecting the liquid tank and the container; a liquid discharge pipe through which the electrolytic solution flows from the container to the liquid tank; and a supply device provided in the liquid supply pipe for supplying the electrolytic solution from the liquid tank to the container, A voltage is applied between the anode and the substrate while the solid electrolyte membrane is in contact with the substrate to reduce the metal ions contained in the solid electrolyte membrane, thereby forming the metal coating. A film forming apparatus for forming a metal film on a surface of a base material, wherein the film forming apparatus is provided between the supply device and the container in the liquid supply pipe, and the gas contained in the electrolytic solution from the electrolytic solution.

According to the present invention, in the film forming apparatus, the electrolytic solution containing metal ions flows from the liquid tank to the container through the liquid supply pipe, and from the container to the liquid tank through the liquid discharge pipe. In the film forming apparatus, a voltage is applied between the anode and the substrate by the power supply while the solid electrolyte membrane is in contact with the substrate. As a result, the metal ions contained inside the solid electrolyte membrane are reduced, so that a metal film is formed on the surface of the substrate. The film-forming apparatus has a gas-liquid separator provided between the supply device and the container in the liquid supply pipe for separating the gas contained in the electrolytic solution from the electrolytic solution. Therefore, even if gas such as air existing in the liquid supply pipe and the liquid discharge pipe is mixed with the electrolytic solution when the electrolytic solution flows between the liquid tank and the container, the electrolytic solution can be stored. Gases (bubbles) contained in the electrolyte can be separated from the electrolyte before it is delivered to the body. Therefore, it is possible to avoid forming the metal film in a state where gas is mixed in the electrolytic solution, thereby avoiding formation of pits, pinholes, and the like in the formed metal film. Therefore, appearance defects of the metal film are suppressed, and the film formation quality can be improved.

As a preferred embodiment, the metal of the metal film is a metal that forms metal ions having a valence of 2 or higher, and the anode is a soluble anode made of the same metal as the metal film. Further, the gas-liquid separator has a gas discharge port for discharging the gas separated from the electrolyte, and the gas is supplied to the electrolyte contained in the liquid tank through the gas discharge port. , is connected to the liquid tank.

According to this aspect, due to the dissolution of the anode during the formation of the metal film, monovalent metal ions are introduced into the electrolytic solution inside the container, and the monovalent metal ions are discharged to the liquid tank together with the electrolytic solution. may occur. Even in this case, since the gas containing oxygen gas is supplied to the electrolyte in the liquid tank through the gas outlet, unstable monovalent metal ions are oxidized to stable divalent or higher metal ions. be able to. As a result, monovalent metal ions are chemically unstable and tend to settle in the liquid tank as sludge such as metal powder or oxides. It is possible to avoid the formation of sludge such as metal oxides or metal powders due to the metal ions. According to this aspect, even if the metal ions contained in the electrolytic solution are consumed by the formation of the metal film, the metal ions can be replenished by the dissolution of the anode. Therefore, a uniform metal film can be formed while replenishing the electrolytic solution with metal ions by dissolving the anode.

In a preferred embodiment, the film forming apparatus includes a base supporting the base material below the container so that the base material faces the solid electrolyte membrane, and a base supporting the solid electrolyte membrane and the base material. an elevating device for lifting and lowering at least one of the container and the base so that the container and the base can be freely contacted and separated; and a control device for controlling the operation of the lifting device and the gas-liquid replacement device, wherein the control device controls the operation of the gas-liquid replacement device to control the container The inside of is changed from the electrolytic solution to the air, and then the operation of the lifting device is controlled to separate the solid electrolyte membrane from the substrate.

According to this aspect, the solid electrolyte membrane is separated from the substrate after the electrolytic solution inside the container is replaced with the atmosphere. Therefore, when the container is separated from the base, the solid electrolyte membrane is not deformed by the weight of the electrolyte. By the way, when replacing the electrolytic solution in the container with the air, the electrolytic solution and the air may be mixed inside the container, and the electrolytic solution returned to the liquid tank may contain the air. In this way, even if the electrolyte in the liquid tank contains air, the electrolyte is supplied to the container after separating the gas contained in the electrolyte (for example, air). Poor appearance can be suppressed.

ADVANTAGE OF THE INVENTION According to this invention, generation|occurrence|production of the appearance defect of a metal film can be suppressed and the film-forming quality can be improved.

1 is a schematic cross-sectional view of a metal film deposition apparatus according to a first embodiment of the present invention; FIG. FIG. 2 is a schematic cross-sectional view of the film forming apparatus shown in FIG. 1, showing a state in which an electrolytic solution is injected; 2 is a flowchart for explaining control of the film forming apparatus shown in FIG. 1; FIG. 5 is a schematic cross-sectional view of a metal film deposition apparatus according to a second embodiment of the present invention. 5 is a schematic cross-sectional view of the film forming apparatus shown in FIG. 4, showing a state in which an electrolytic solution is injected; FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal film forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic cross-sectional view of a metal film deposition apparatus 1A according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the film forming apparatus 1A shown in FIG. 1, showing a state in which the electrolytic solution L is injected.

As shown in FIGS. 1 and 2, the film forming apparatus 1A includes an anode 11, a solid electrolyte membrane 13 disposed between the anode 11 and the substrate B, and a voltage between the anode 11 and the substrate B. and a container 15 containing the electrolyte solution L containing the anode 11 and metal ions and having the opening 15 a covered with the solid electrolyte membrane 13 . In addition, as shown in FIG. 1, the film forming apparatus 1A further includes a base 20 on which the substrate B is placed, and a linear motion actuator (lifting device) 70, if necessary. good too.

The film forming apparatus 1A applies a voltage between the anode 11 and the substrate B while the solid electrolyte membrane 13 is in contact with the substrate B, thereby reducing the metal ions contained inside the solid electrolyte membrane 13. It is an apparatus for forming a metal film (not shown) on the surface B1 of the substrate B by doing so. In the present embodiment, for convenience of explanation, it is assumed that the solid electrolyte membrane 13 is arranged below the anode 11 and the substrate B is further arranged below it, and the positional relationship of the constituent members of the film forming apparatus 1A is changed. Identify. However, as long as a metal film can be formed on the surface B1 of the substrate B, the positional relationship is not limited to this. For example, even if the film forming apparatus 1A in FIG. good.

The base material B functions as a cathode. The material of the base material B is not particularly limited as long as it functions as a cathode (that is, a surface having conductivity), and may be made of metal materials such as aluminum and iron, and may be made of resin, ceramics, or the like. The surface may be coated with a metal layer such as copper, nickel, silver, or iron.

The base 20 holds the substrate B below the container 15 so that the substrate B faces the solid electrolyte membrane 13 . Base 20 may be formed from an insulating material. In this case, the base material B is directly connected to the negative electrode side conductor 14a extending inside the base 20, and is electrically connected to the negative electrode of the power supply section 14 via this negative electrode side conductor 14a. Also, the base 20 may be made of a conductive material (for example, made of metal). In this case, the negative electrode of the power supply section 14 is connected to the base 20 via the negative electrode conductor 14a. Thereby, the base material B is electrically connected to the negative electrode of the power supply unit 14 via the base 20 and the negative electrode-side conducting wire 14a.

The anode 11 has a shape corresponding to the film-forming region of the substrate B. As shown in FIG. The film-forming region of the substrate B means the portion of the surface B1 of the substrate B facing the anode 11 . Anode 11 is a non-porous (for example, non-porous) anode made of the same metal as the metal of the metal film, and is a block-shaped or plate-shaped anode. Examples of materials for the anode 11 include copper, nickel, gold, silver, and iron. In the present embodiment, the anode 11 is dissolved by applying a voltage using the power supply unit 14. However, for example, if the film is formed using only the electrolytic solution L containing metal ions, the anode 11 does not need to be dissolved. good. Anode 11 may be porous, but is more preferably non-porous. By using the non-porous anode 11 , the metal film formed on the substrate B is less affected by the state of the surface of the anode 11 .

The anode 11 is mounted in a container 15 made of, for example, an insulating material. In this case, the anode 11 is electrically connected to the positive electrode of the power supply section 14 via the positive electrode side conducting wire 14b. At least part of the container 15 may be made of a conductive material (for example, metal) as long as a metal film can be formed by applying a voltage between the anode 11 and the base material B. In this case, the power supply unit 14 and the anode 11 may be electrically connected via the container 15 and the positive electrode side conductor 14b.

The electrolytic solution L is a solution containing the metal of the metal film to be formed as described above in the form of ions, and examples of the metal include copper, nickel, gold, silver, and iron. can. The electrolytic solution L is an aqueous solution obtained by dissolving (ionizing) these metals with an acid such as nitric acid, phosphoric acid, succinic acid, nickel sulfate, or pyrophosphoric acid. For example, when the metal is nickel, the electrolytic solution L can be, for example, an aqueous solution of nickel nitrate, nickel phosphate, nickel succinate, nickel sulfate, nickel pyrophosphate, or the like. Further, for example, when the metal is copper, the electrolytic solution L can be an aqueous solution containing copper sulfate, copper pyrophosphate, or the like.

The solid electrolyte membrane 13 is a flexible membrane that can be impregnated (contained) with metal ions when brought into contact with the electrolytic solution L described above. The solid electrolyte membrane 13 is not particularly limited as long as the metal ions are reduced in the base material B when a voltage is applied by the power supply unit 14 and the metal derived from the metal ions can be deposited. Materials for the solid electrolyte membrane 13 include, for example, fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, ions such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd. A resin having an exchange function can be mentioned. As shown in FIGS. 1 and 2, the solid electrolyte membrane 13 has a facing surface 13a that faces the surface B1 of the substrate B when attached to the container 15. As shown in FIGS.

As shown in FIG. 1, an anode 11 and a solid electrolyte membrane 13 are attached to the housing 15, and the housing 15, the anode 11, and the solid electrolyte membrane 13 form a housing space 15d for housing the electrolytic solution L. It is The anode 11 is attached to the inner surface of the container 15 arranged so as to surround the periphery of the anode 11 . Further, the container 15 has an opening 15a that opens toward the base material B side. The opening 15a opens downward, and the solid electrolyte membrane 13 is attached to the container 15 via, for example, a sealing material (not shown) so as to cover the opening 15a. The anode 11 and the solid electrolyte membrane 13 are arranged apart from each other and are in a non-contact state, and the accommodation space 15d between them is filled with the electrolytic solution L. As shown in FIG. Thus, the container 15 has a structure in which the electrolytic solution L contained in the container space 15 d directly contacts the anode 11 and the solid electrolyte membrane 13 . The container 15 is made of a material that is insoluble in the electrolytic solution L. As shown in FIG.

Further, the container 15 is formed with a supply channel 15b for supplying the electrolytic solution L to the accommodation space 15d and a discharge channel 15c for discharging the electrolytic solution L from the accommodation space 15d. The supply channel 15b and the discharge channel 15c are holes that communicate with the accommodation space 15d, and are formed with the accommodation space 15d interposed therebetween. The supply channel 15b is fluidly connected to a liquid supply pipe 50, which will be described later, and the discharge channel 15c is fluidly connected to a liquid discharge pipe 52, which will be described later. Note that the film forming apparatus 1A may have a heating device (not shown) on the upstream side of the supply channel 15b (for example, in the liquid tank T containing the electrolytic solution L). The electrolytic solution L may be supplied to the accommodation space 15d through the liquid supply pipe 50 and the supply channel 15b.

The direct-acting actuator 70 of the film forming apparatus 1A raises and lowers at least one of the container 15 and the base 20 so that the solid electrolyte membrane 13 and the base material B can be brought into contact with each other. In this embodiment, the case where the base 20 is fixed and the container 15 is moved up and down by the direct-acting actuator 70 will be described. As shown in FIGS. 1 and 2 , the direct acting actuator 70 is provided on the upper portion of the container 15 . Linear actuator 70 is an electric actuator, and includes, for example, guide 71 to which a motor (not shown) is attached, and rod 72 that moves linearly with respect to guide 71 . The rod 72 converts rotary motion of the motor into linear motion by, for example, a ball screw or the like (not shown). This linear motion actuator 70 makes it possible to move the container 15 up and down with respect to the base 20 to bring the solid electrolyte membrane 13 into contact with and separate from the substrate B. As shown in FIG. Note that the linear actuator 70 may be provided below the base 20 . In this case, the solid electrolyte membrane 13 can be brought into contact with and separated from the substrate B by raising and lowering the base 20 . Moreover, a hydraulic or pneumatic cylinder may be used as a device for raising and lowering the container 15 .

The film forming apparatus 1A also includes a liquid tank T, a liquid supply pipe 50, a liquid discharge pipe 52, a pump (supply device) P, a gas-liquid separator 30, a gas-liquid replacement device 80, and a control device 90. And prepare.

Next, a mechanism for circulating the electrolytic solution L in the film forming apparatus 1A will be described. As shown in FIG. 1, the liquid tank T contains an electrolytic solution L. As shown in FIG. A liquid supply pipe 50 connects the liquid tank T and the container 15 . Specifically, one end of the liquid supply pipe 50 is fluidly connected to a liquid tank T in which the electrolytic solution L is stored, and the other end of the liquid supply pipe 50 is fluidly connected to the supply channel 15b of the container 15. It is

A three-way valve 60 is provided in the liquid supply pipe 50 . The three-way valve 60 switches the flow direction of the electrolytic solution L. As shown in FIG. Specifically, the three-way valve 60 controls the flow direction of the electrolytic solution L from the liquid tank T to the container 15 through the liquid supply pipe 50 and the flow direction of the electrolytic solution L from the container 15 to the container T through the liquid return pipe 56 described later. and the direction of flow of the electrolytic solution L toward . Also, by closing the three-way valve 60, the electrolyte L flows from the liquid tank T to the container 15 through the liquid supply pipe 50, and the electrolyte L flows from the container 15 to the liquid tank T through the liquid return pipe 56. can stop That is, when the three-way valve 60 is switched so that the electrolytic solution L flows from the liquid tank T to the container 15 , the electrolytic solution L flows from the liquid tank T to the container 15 through the inside of the liquid supply pipe 50 . The liquid supply pipe 50 is provided with a pump P that supplies the electrolytic solution L from the liquid tank T to the container 15 . Therefore, when the pump P rotates forward, the electrolytic solution L is sucked from the liquid tank T into the liquid supply pipe 50, and the electrolytic solution L is transferred through the gas-liquid separator 30 and the three-way valve 60, which will be described later. It is pressure-fed into the accommodation space 15 d of the accommodation body 15 . The pump P is configured to rotate forward/reversely. When the pump P rotates forward, the electrolyte L is supplied from the liquid tank T to the container 15 as described above. On the other hand, as will be described in detail later, when the pump P rotates in the reverse direction, the electrolytic solution L is supplied from the container 15 to the liquid tank T through the liquid return pipe 56 .

As shown in FIG. 1, the gas-liquid separator 30 of the film forming apparatus 1A is provided between the pump P and the container 15 in the liquid supply pipe 50, and separates the gas (bubbles) contained in the electrolytic solution L into electrolysis. It separates from the liquid L. The gas-liquid separator 30 includes a liquid outlet 32 that releases the liquid phase component and a gas outlet 34 that releases the gas phase component. The electrolyte L from which the gas is separated by the gas-liquid separator 30 is introduced into the container 15 via the liquid outlet 32 and the liquid supply pipe 50 . The gas separated from the electrolyte L by the gas-liquid separator 30 may be released into the atmosphere, for example, through the gas release port 34 . The gas-liquid separator 30 may operate, for example, by a surface tension method, or may operate by a centrifugal force separation method using swirling flow. Since the configuration of the gas-liquid separator 30 itself is known, its detailed description is omitted.

As shown in FIG. 1, the liquid discharge pipe 52 connects the liquid tank T and the container 15 . Specifically, one end of the liquid discharge pipe 52 is fluidly connected to the discharge channel 15c of the container 15, and the other end of the liquid discharge pipe 52 is fluidly connected to the liquid tank T. As shown in FIG. The electrolytic solution L flows from the containing body 15 to the liquid tank T through the inside of the liquid discharge pipe 52 .

A pressure regulating valve 58 is interposed in the liquid discharge pipe 52 to prevent the pressure (liquid pressure) of the electrolytic solution L contained in the containing space 15d from exceeding a predetermined pressure. Further, the pressure regulating valve 58 can seal the interior of the housing space 15d by closing the three-way valve 60, and as a result, the liquid pressure of the electrolytic solution L is maintained at a predetermined pressure or less. With such a circulation mechanism, the electrolytic solution L in which the concentration of metal ions has been adjusted to a predetermined concentration is supplied from the supply channel 15b to the accommodation space 15d, and the electrolytic solution L used in the accommodation space 15d at the time of film formation is supplied. can be returned to the liquid tank T through the discharge channel 15c.

A relief valve 62 is interposed between the containing body 15 and the pressure regulating valve 58 in the liquid discharge pipe 52 . The relief valve 62 is opened, for example, when the inside of the liquid discharge pipe 52 becomes negative pressure (pressure lower than the atmospheric pressure), and introduces the outside air into the housing space 15 d of the container 15 . This relief valve 62 will be described later.

The gas-liquid replacement device 80 returns the electrolytic solution L stored in the container 15 to the liquid tank T and introduces the air into the container 15 . The gas-liquid replacement device 80 returns the electrolytic solution L from the container 15 to the liquid tank T through the liquid return pipe 56 . One end of the liquid return pipe 56 is fluidly connected to the supply channel 15b of the container 15, and the other end of the liquid return pipe 56 is fluidly connected to the liquid tank T. As shown in FIG. In this embodiment, the liquid return pipe 56 shares a portion thereof with a portion of the liquid supply pipe 50 . Note that the liquid return pipe 56 may be a pipe separate from the liquid supply pipe 50 .

The gas-liquid replacement device 80 includes a pump P, a three-way valve 60, and a relief valve 62. In this embodiment, a case where the pump P is a component of the gas-liquid replacement device 80 will be described. When the three-way valve 60 is switched so that the electrolytic solution L flows from the container 15 to the liquid tank T, the pump P is rotated in the reverse direction so that the electrolytic solution L flows through the liquid return pipe 56 from the container 15. Communicate with the liquid tank T. That is, when the pump P rotates in the reverse direction, the electrolytic solution L is sucked into the liquid return pipe 56 from the accommodation space 15d of the container 15, and the electrolytic solution L is pressure-fed to the liquid tank T. As shown in FIG. At this time, the pump P continues to rotate in the reverse direction, so that the relief valve 62 is opened and air is introduced into the housing space 15 d of the housing body 15 . In this manner, the gas-liquid exchange device 80 exchanges the electrolytic solution L contained in the containing space 15d with air by reverse rotation of the pump P, switching of the three-way valve 60, and opening of the relief valve 62. It should be noted that an example of the gas-liquid replacement device 80 has been described in the present embodiment. For example, the gas-liquid exchange device 80 may return the electrolyte L stored in the storage space 15d to the liquid tank T through the liquid discharge pipe 52 by pumping compressed air from the supply channel 15b of the storage body 15. good. In this case, the exchange of the electrolytic solution L and the atmosphere is completed by the compressed air remaining in the housing space 15d.

The control device 90 controls the operations of the direct-acting actuator 70 and the gas-liquid replacement device 80 (that is, the pump P and the three-way valve 60). The film forming apparatus 1A includes a first pressure sensor 92 provided on the liquid discharge pipe 52, a second pressure sensor 93 provided on the liquid return pipe 56, and a stroke sensor (not shown) provided on the linear actuator 70. may contain. The first pressure sensor 92 detects the internal pressure of the liquid discharge pipe 52 and transmits the detected pressure signal to the control device 90 via the first pressure signal line 95 . The second pressure sensor 93 also detects the internal pressure of the liquid return pipe 56 and transmits the detected pressure signal to the control device 90 via the second pressure signal line 96 . A stroke sensor (not shown) detects the stroke amount of the rod 72 with respect to the guide 71 and transmits the detected stroke signal to the control device 90 via the stroke signal line 94 . The signal input to the control device 90 is an example, and in addition to the above-described signals, for example, signals related to the rotation speed and rotation direction of the pump P may be input.

The control device 90 receives the above-described signals and controls the operation of the constituent elements of the film forming apparatus 1A (for example, the pump P, the power supply section 14, the three-way valve 60, the direct-acting actuator 70). Control of the film forming apparatus 1A using the control device 90 will be described with reference to FIG.

The control device 90 controls a conveying device (not shown) and the like, thereby setting the substrate B on the base 20 (S100). At this time, the alignment of the substrate B with respect to the anode 11 attached to the container 15 may be adjusted, and the temperature of the substrate B may be adjusted. Next, a step of bringing the facing surface 13a of the solid electrolyte membrane 13 into contact with the surface B1 of the substrate B is performed (see FIG. 2). In this process, the control device 90 transmits a drive signal for extending the rod 72 to the linear motion actuator 70 via the stroke signal line 94 (S110). As a result, the rod 72 moves downward with respect to the guide 71, and the container 15 descends. Then, the solid electrolyte membrane 13 contacts the substrate B from above. The control device 90 receives a stroke signal regarding the stroke amount of the rod 72 from the linear motion actuator 70 via the stroke signal line 94 . When the stroke signal reaches a predetermined value, the control device 90 determines that the solid electrolyte membrane 13 has come into contact with the base material B, and stops the descent of the container 15 .

Next, a step of accommodating the electrolytic solution L between the anode 11 and the solid electrolyte membrane 13 is performed (see FIG. 2). In this process, the control device 90 switches the three-way valve 60 so that the electrolytic solution L flows from the liquid tank T to the container 15 through the liquid supply pipe 50 . , a predetermined valve switching signal is transmitted (S120). Next, the control device 90 transmits a predetermined drive signal to the pump P via the pump signal line 99 so that the pump P rotates forward (S130). As a result, the electrolyte L sucked from the liquid tank T by the pump P is supplied to the container 15 via the gas-liquid separator 30 and the three-way valve 60 .

Next, the control device 90 determines whether or not the pressure (fluid pressure) of the electrolytic solution L in the housing space 15d of the housing 15 is equal to or higher than a predetermined pressure (S140). Specifically, the control device 90 receives the hydraulic pressure inside the liquid discharge pipe 52 via the first pressure signal line 95 and determines whether or not the hydraulic pressure is equal to or higher than a predetermined pressure. When the controller 90 determines that the hydraulic pressure is not equal to or higher than the predetermined pressure (NO in S140), the controller 90 controls the pump P to continue rotating in the forward direction. On the other hand, when the control device 90 determines that the hydraulic pressure is equal to or higher than the predetermined pressure (YES in S140), the control device 90 causes the pump P to stop driving via the pump signal line 99. A stop signal is transmitted (S150). As a result, the forward rotation of the pump P is stopped, and the supply of the electrolytic solution L from the liquid tank T to the container 15 is stopped. Next, the control device 90 transmits a signal for closing the three-way valve 60 to the three-way valve 60 via the valve signal line 98 (S160). As a result, the inside of the housing space 15d is sealed by the pressure regulating valve 58 and the three-way valve 60, and the liquid pressure of the electrolytic solution L is maintained at a predetermined pressure or less.

In this way, in a state in which the base material B is pressed by the solid electrolyte membrane 13 due to the liquid pressure of the electrolyte solution L, the control device 90 controls the power supply unit 14 via the voltage signal line 97 to connect the anode 11 and A command to apply a voltage between the substrate B is executed (S170). As a result, the metal ions contained in the solid electrolyte membrane 13 migrate to the surface of the substrate B in contact with the solid electrolyte membrane 13 and are reduced on the surface B1 of the substrate B. As shown in FIG. As a result, the metal is deposited on the surface B1 of the substrate B, and a metal film is formed on the surface B1 of the substrate B. At this time, since the electrolyte solution L is accommodated in the accommodation space 15d, metal ions can be supplied to the solid electrolyte membrane 13 at all times.

Next, the control device 90 uses its built-in timer function to determine whether the elapsed time of voltage application by the power supply unit 14 has passed a predetermined time (S180). When the control device 90 determines that the voltage application has not passed the predetermined time (NO in S180), the control device 90 controls the power supply unit 14 to continue voltage application. This is because it is determined that the thickness of the metal film on the surface B1 of the substrate B is not sufficient. On the other hand, if the control device 90 determines that the voltage application elapsed time has passed the predetermined time (YES in S180), the control device 90 sends the power supply unit 14 via the voltage signal line 97 to A command to end the voltage application by the power supply unit 14 is executed (S190). This is because it is determined that the thickness of the metal coating on the surface B1 of the substrate B is sufficient.

Next, the control device 90 controls the operation of the gas-liquid exchange device 80 to change the inside of the container 15 from the electrolyte L to the atmosphere (S200, S210, S220), and then controls the operation of the linear actuator 70. By doing so, the solid electrolyte membrane 13 is separated from the substrate B (S230). Specifically, in order to switch the three-way valve 60 so that the electrolytic solution L flows from the container 15 to the liquid tank T through the liquid return pipe 56, the controller 90 controls the three-way valve 60 via the valve signal line 98. In response, a predetermined valve switching signal is transmitted (S200). Next, the controller 90 transmits a predetermined drive signal to the pump P via the pump signal line 99 so that the pump P rotates in the reverse direction (S210). As a result, the electrolyte L sucked from the container 15 by the pump P is supplied to the liquid tank T via the three-way valve 60 . At this time, as the pump P continues to rotate in the reverse direction, the pressure in the accommodation space 15d of the accommodation body 15 decreases (for example, becomes a negative pressure), so the relief valve 62 is opened, and the atmosphere is introduced into the accommodation space 15d of the accommodation body 15. be introduced.

Next, the control device 90 determines whether or not the replacement of the storage space 15d of the storage body 15 (that is, the replacement of the electrolytic solution L with the atmosphere) has been completed (S220). Specifically, the controller 90 receives the internal pressure of the liquid return pipe 56 via the second pressure signal line 96 and determines whether the internal pressure has reached atmospheric pressure. When the control device 90 determines that the internal pressure has not reached the atmospheric pressure (that is, is negative pressure) (NO in S220), the control device 90 performs control to continue the reverse rotation of the pump P. . On the other hand, when the controller 90 determines that the internal pressure has reached atmospheric pressure (YES in S220), the controller 90 returns the rod 72 to the linear actuator 70 via the stroke signal line 94. A drive signal is transmitted (S230). As a result, the rod 72 moves upward with respect to the guide 71, and the container 15 rises. Then, the solid electrolyte membrane 13 is separated from the base material B. When the stroke amount of the rod 72 received via the stroke signal line 94 reaches a predetermined value, the control device 90 determines that the solid electrolyte membrane 13 has separated from the substrate B, and causes the container 15 to rise. Stop.

Finally, the control device 90 controls a conveying device (not shown) and the like to remove the substrate B from the base 20 (S240). As described above, a series of control of the film forming apparatus 1A using the control device 90 is completed, and the control returns to the start.

Actions and effects of the film forming apparatus 1A according to this embodiment will be described below.

As described above, in the film forming apparatus 1A according to the present embodiment, the electrolytic solution L containing metal ions flows from the liquid tank T to the container 15 through the liquid supply pipe 50, and flows from the container 15 to the liquid tank T. The discharge pipe 52 flows. The film forming apparatus 1A has a gas-liquid separator 30 provided between the pump P and the container 15 in the liquid supply pipe 50 to separate the gas contained in the electrolytic solution L from the electrolytic solution L. As shown in FIG. Therefore, even if gas such as air present in the liquid supply pipe 50 and the liquid discharge pipe 52 is mixed with the electrolytic solution L when the electrolytic solution L flows between the liquid tank T and the container 15 , the gas (bubbles) can be separated from the electrolyte L before the electrolyte L is supplied to the container 15 . Therefore, it is possible to avoid forming the metal film in a state in which gas is mixed in the electrolytic solution L, thereby avoiding the formation of pits, pinholes, and the like in the formed metal film. Therefore, appearance defects of the metal film are suppressed, and the film formation quality can be improved.

Further, the control device 90 separates the solid electrolyte membrane 13 from the base material B after the inside of the container 15 is changed from the electrolytic solution L to the atmosphere. Therefore, when container 15 is separated from base 20 (for example, lifted), deformation of solid electrolyte membrane 13 due to the weight of electrolytic solution L does not occur. By the way, when the electrolytic solution L inside the container 15 is replaced with air, the electrolytic solution L and the air may be mixed inside the container 15, and the electrolytic solution L returned to the liquid tank T contains the air. Sometimes. As described above, according to the film forming apparatus 1A according to the present embodiment, even if the electrolytic solution L in the liquid tank T contains air, the electrolytic solution obtained by separating the gas (for example, air) contained in the electrolytic solution L is separated from the electrolytic solution L. Since L is supplied to the container 15, it is possible to suppress appearance defects of the metal film caused by air bubbles.

<Second embodiment>
FIG. 4 is a schematic cross-sectional view of a metal film deposition apparatus 1B according to a second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the film forming apparatus 1B shown in FIG. 4, showing a state in which an electrolytic solution has been injected. A film forming apparatus 1B according to the second embodiment differs from the film forming apparatus 1A according to the first embodiment in the connection destination of the gas discharge port 34 of the gas-liquid separator 30 . In addition, the film forming apparatus 1B according to the present embodiment is different from the film forming apparatus 1A according to the first embodiment in that the type of the anode 11 and the type of metal ions contained in the electrolytic solution L are limited. are different. Hereinafter, configurations having the same or similar functions as those of the film forming apparatus 1A according to the first embodiment are denoted by the same reference numerals as those of the film forming apparatus 1A according to the first embodiment, and descriptions thereof are omitted. will be explained.

As shown in FIGS. 4 and 5, the gas-liquid separator 30 has a gas discharge port 34 for discharging the gas separated from the electrolytic solution L. As shown in FIGS. The gas discharge port 34 is connected to the liquid tank T so that gas is supplied to the electrolytic solution L contained in the liquid tank T. As shown in FIG. Specifically, the gas discharge port 34 is connected to the liquid tank T via the gas supply pipe 54 . One end of the gas supply pipe 54 is fluidly connected to the gas discharge port 34 of the gas-liquid separator 30 , and the other end of the gas supply pipe 54 is fluidly connected to the liquid tank T. The gas separated from the electrolytic solution L flows through the gas supply pipe 54 and the gas discharge port 34 to the liquid tank T. As shown in FIG.

The anode 11 of the film forming apparatus 1B according to this embodiment is a soluble anode made of the same metal as the metal film formed on the surface B1 of the substrate B. As shown in FIG. That is, the anode 11 is made of a material that is soluble in the electrolytic solution L. Examples of materials for the anode 11 include copper, nickel, zinc, and tin. For example, when the anode 11 is a soluble anode made of oxygen-free copper, dissolution of the anode 11 may introduce monovalent copper ions into the electrolytic solution L inside the container 15 . In addition, in the film forming apparatus 1B, the metal of the metal film formed on the surface B1 of the substrate B is a metal that becomes a metal ion having a valence of 2 or more. The metals may include copper, nickel, tin and zinc.

As described above, in the film forming apparatus 1B according to the present embodiment, the metal of the metal film formed on the surface B1 of the substrate B is a metal that becomes a metal ion having a valence of 2 or more, and the anode 11 is a metal film. is a soluble anode made of the same metal as Also, the gas discharge port 34 of the gas-liquid separator 30 is fluidly connected to the liquid tank T via the gas supply pipe 54 .

In the film forming apparatus 1B according to the present embodiment, for example, when the anode 11 is a soluble anode made of copper, monovalent copper ions are generated inside the container 15 by dissolving the anode 11 when forming a metal film. Introduced into the electrolytic solution L, the monovalent copper ions may be discharged to the liquid tank T together with the electrolytic solution L. Monovalent copper ions may become copper hydroxide in the liquid tank T (Cu ⁺ +H ₂ O→CuOH+H ⁺ ). Since copper hydroxide is chemically unstable, it dehydrates to form copper (I) oxide (2CuOH→2CuO+H ₂ O), which may precipitate in the liquid tank T. In addition, due to transfer of electrons between monovalent copper ions, they become metal ions with a valence of 2 or more (2Cu ⁺ →Cu+Cu ²⁺ ), and the metal aggregates into metal powder, which may precipitate in the liquid tank T. . However, according to the film forming apparatus 1B, the gas containing oxygen gas is supplied to the liquid tank T through the gas discharge port 34 of the gas-liquid separator 30, so that unstable monovalent copper ions are converted into stable copper ions. It can be oxidized to divalent or higher copper ions (2Cu ⁺ +1/2O ₂ +2H ⁺ →2Cu ²⁺ +H ₂ O). As a result, it is possible to avoid the generation of sludge such as metal oxides or metal powder due to monovalent copper ions. As a result, the sludge is prevented from being mixed into the container 15, and a uniform metal film can be formed. Further, even if the copper ions contained in the electrolytic solution L are consumed by the formation of the metal film, the copper ions can be replenished to the electrolytic solution L by the dissolution of the anode 11 . Therefore, a homogeneous metal film can be formed while replenishing the electrolyte L with copper ions.

The invention is illustrated by the following examples.

[Example 1]
As a substrate for forming a film on the surface, a glass epoxy substrate (FR-4) was prepared by impregnating a layer of glass fiber cloth with an epoxy resin. A copper foil is formed on the surface of this glass epoxy substrate.

Next, a copper film was formed using the film forming apparatus 1B according to the second embodiment shown in FIGS. A copper sulfate aqueous solution of "1 M CuSO ₄ +0.2 MH ₂ SO ₄ " was used as the electrolytic solution, and a Cu plate was used as the anode. The film formation conditions were as follows: the temperature of the electrolytic solution was set at 70° C., the solid electrolytic film (Nafion (manufactured by DuPont)) with a thickness of 8 μm was brought into close contact with the substrate, the liquid pressure of the electrolytic solution was 0.6 MPa, and the current density was 18 A/. A copper film was formed with dm ² , a film formation area of 100 cm ² , and a cumulative film formation time of 151 seconds. Moreover, as the gas-liquid separator, a general one that operates by a centrifugal force separation method using swirling flow was used.

[Example 2]
A copper film was formed in the same manner as in Example 1. The difference ^from Example 1 is that phosphorous copper is used for the anode, and the conditions shown in FIGS. The difference is that the film is formed using the film forming apparatus 1A according to the first embodiment.

[Comparative Example 1]
A copper film was formed in the same manner as in Example 1. A different point from Example 1 is that the copper film was formed using a film forming apparatus having no gas-liquid separator.

<Confirmation of film formation state>
The ratio of the appearance defect area of the metal film to the film formation area (100 cm ² ) was measured for the substrate on which the film was formed as described above. The area of defective appearance was calculated by measuring the areas of pits and pinholes formed in the metal film. The results are shown in Table 1 (Example 1, Example 2, Comparative Example).

(Results and Discussion)
Here, when the ratio of the appearance-defective area of the metal film to the film-forming area was 10% or more, the appearance was determined to be poor, and when it was less than 10%, the appearance was determined to be good. The 10% is what is used as the threshold for acceptable appearance. As is clear from Table 1, in Examples 1 and 2, the proportion of the area with defective appearance was 0%, and pits and pinholes were not confirmed in the metal film. In Example 1, it is considered that the gas contained in the electrolytic solution is separated by the gas-liquid separator, and the electrolytic solution containing no such gas can be supplied to the container. In addition, it is thought that the monovalent copper ions generated during the formation of the metal film are discharged from the container into the liquid tank. It is considered that the ions can be returned to divalent copper ions. It is believed that this avoids the generation of sludge such as metal powder, thereby preventing the sludge from being supplied to the container together with the electrolytic solution. Thus, in Example 1, it is considered that the generation of pits and pinholes in the metal film can be suppressed. Moreover, in Example 2, it is considered that the gas contained in the electrolytic solution is separated by the gas-liquid separator, and the electrolytic solution containing no such gas can be supplied to the container. Thus, in Example 2, it is considered that the generation of pits and pinholes in the metal film can be suppressed.

On the other hand, in the comparative example, the proportion of the appearance defect area was 25%, and pits and pinholes exceeding the above threshold were confirmed in the metal film. In the comparative example, it is considered that the electrolytic solution containing gas was supplied to the container. In addition, it is thought that the monovalent copper ions generated during the formation of the metal film are discharged from the container into the liquid tank, but it is possible to convert the monovalent copper ions back to divalent copper ions. Instead, it is thought that sludge such as metal powder was supplied to the container together with the electrolyte. For this reason, it is considered that the area of defective appearance is increased in the comparative example.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the film forming apparatuses 1A and 1B according to the above embodiments, and is included in the concept of the present invention and the scope of the claims. including any aspect that can be Moreover, each configuration may be selectively combined as appropriate so as to achieve the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be changed as appropriate according to specific aspects of the present invention.

For example, in the above-described embodiment, the three-way valve 60 is closed to stop the circulation of the electrolytic solution L, and the voltage is applied between the anode 11 and the substrate B by the power supply unit 14 (see FIG. 3). (See S150 to S190). However, the three-way valve 60 does not have to be closed when the voltage is applied by the power supply unit 14 . In this case, by continuing forward rotation of the pump P, the hydraulic pressure of the electrolytic solution L can be maintained at a predetermined pressure. As a result, the gas contained in the electrolytic solution L can be separated both before and during the formation of the metal film.

1A, 1B: film forming apparatus, 11: anode, 13: solid electrolyte membrane, 14: power supply unit, 15: container, 15a: opening, 20: base, 30: gas-liquid separator, 34: gas discharge port , 50: liquid supply pipe, 52: liquid discharge pipe, 70: linear actuator (lifting device), 80: gas-liquid replacement device, 90: control device, B: base material, B1: surface, L: electrolyte solution, P : pump (supply device), T: liquid tank

Claims (3)

an anode;
a solid electrolyte membrane disposed between the anode and the substrate;
a power supply section that applies a voltage between the anode and the base material using the base material as a cathode;
a container containing the anode and an electrolytic solution containing metal ions, and having an opening facing the base material covered with the solid electrolyte membrane;
a liquid tank containing the electrolyte;
a liquid supply pipe connecting the liquid tank and the containing body, through which the electrolytic solution flows from the liquid tank to the containing body;
a liquid discharge pipe connecting the liquid tank and the container, through which the electrolytic solution flows from the container to the liquid tank;
a supply device provided in the liquid supply pipe for supplying the electrolytic solution from the liquid tank to the container,
A voltage is applied between the anode and the substrate while the solid electrolyte membrane is in contact with the substrate to reduce metal ions contained in the solid electrolyte membrane, thereby forming a metal film. A film forming apparatus for forming a metal film on the surface of the base material,
The film forming apparatus has a gas-liquid separator that is provided between the supply device and the container in the liquid supply pipe and separates a gas contained in the electrolytic solution from the electrolytic solution. A film forming apparatus for forming a metal film. The metal of the metal film is a metal that becomes a metal ion having a valence of 2 or more,
The anode is a soluble anode made of the same metal as the metal film,
The gas-liquid separator has a gas release port for releasing the gas separated from the electrolyte,
2. The metal film forming apparatus according to claim 1, wherein the gas discharge port is connected to the liquid tank so as to supply the gas to the electrolytic solution contained in the liquid tank. membrane device. The film forming apparatus is
a base that holds the base material below the container so that the base material faces the solid electrolyte membrane;
an elevating device for elevating 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 each other;
a gas-liquid exchange device that returns the electrolyte contained in the container to the liquid tank and introduces air into the container;
a control device that controls the operation of the lifting device and the gas-liquid replacement device;
The control device controls the operation of the gas-liquid exchange device to switch the inside of the container from the electrolytic solution to the air, and then controls the operation of the elevating device to move the solid electrolyte membrane to the substrate. 3. The apparatus for depositing a metal film according to claim 1 or 2, characterized in that it separates from the .

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