Metal film forming apparatus and method

Abstract

To provide a film forming apparatus with which after a metal film is formed, an electrolyte film can be easily separated from a base material while suppressing the elongation of the electrolyte film.SOLUTION: A control device 60 of a film forming apparatus 1 controls a lifting operation by a lifting device 70 so that a base material W is in contact with an electrolyte film 13, and concurrently controls a suction operation by a suction pump 52. Then, the control device 60 controls an application operation by a power supply part 19 until a metal film F has a prescribed film thickness after the base material W is in contact with the electrolyte film 13, and after the completion of the application operation, controls the lifting operation by the lifting device 70 so that the base material W is separated from the electrolyte film 13, and concurrently controls a pressure-feeding operation by an air pump 51.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film forming apparatus and a film forming method for forming a metal film on a surface of a substrate. [Background technology]

[0002] As an example of this type of technology, Patent Document 1 proposes a film forming apparatus for forming a metal film on the surface of a substrate. This film forming apparatus includes an anode, an electrolyte membrane disposed between the anode and the substrate serving as the cathode, and a power supply unit for applying a voltage between the anode and the substrate. The film forming apparatus further includes a container for containing a plating solution between the anode and the electrolyte membrane so as to be in contact with the anode and the electrolyte membrane, and a suction device for suctioning air present between the electrolyte membrane and the substrate when the electrolyte membrane and the substrate are brought into contact with each other. With this film forming apparatus, the suction device is provided, so that the metal film can be formed while suppressing the inclusion of air between the electrolyte membrane and the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-051701 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, after forming a metal film using the film forming apparatus described in Patent Document 1, when attempting to separate the electrolyte membrane from the substrate, the electrolyte membrane may be stretched because it may be in close contact with the metal film.

[0005] The present invention has been made in consideration of these points, and its object is to provide a film forming apparatus that can easily separate an electrolyte membrane from a substrate after formation of a metal coating, while preventing the electrolyte membrane from being stretched. [Means for solving the problem]

[0006] In consideration of the above problems, a metal film forming apparatus according to the present invention is a film forming apparatus comprising an anode, an electrolyte membrane disposed between the anode and a substrate, a container that contains the anode and a plating solution and has an opening on the substrate side covered with the electrolyte membrane, and a power supply unit that applies a voltage between the anode and the substrate that serves as a cathode, and forms a metal film derived from metal ions in the plating solution on a surface of the substrate by applying the voltage with the electrolyte membrane in contact with the substrate, the film forming apparatus comprising a mounting table on which the substrate is placed, a lifting device that raises and lowers at least one of the container and the mounting table so that the electrolyte membrane can be brought into contact with and separated from the substrate, and a vacuum pump that sucks in air present between the substrate placed on the mounting table and the electrolyte membrane. the substrate is placed on the mounting table, and the control device controls the lifting operation by the lifting device, the suction operation by the suction device, the application operation by the power supply unit, and the pumping operation by the pumping device, wherein the control device controls the lifting operation by the lifting device while controlling the lifting operation by the lifting device so that the substrate contacts the electrolyte membrane, controls the application operation by the power supply unit after the substrate contacts the electrolyte membrane until the metal coating has a predetermined thickness, and after the application operation is completed, controls the lifting operation by the lifting device while controlling the pumping operation by the pumping device so that the substrate is separated from the electrolyte membrane.

[0007] According to the present invention, first, the control device controls the lifting operation by the lifting device so that the substrate contacts the electrolyte membrane, while controlling the suction operation by the suction device. This control allows the electrolyte membrane to contact the substrate while the suction device sucks in air between the electrolyte membrane covering the opening formed in the housing and the substrate arranged opposite the electrolyte membrane. As a result, air is prevented from being trapped between the electrolyte membrane and the substrate, and the electrolyte membrane can be tightly attached to the substrate.

[0008] Next, the control device controls the application operation by the power supply unit after the substrate contacts the electrolyte membrane until the metal coating reaches a predetermined thickness. With this control, when a voltage is applied between the anode and the substrate with the electrolyte membrane in contact with the substrate, metal ions move to the surface side of the substrate through the electrolyte membrane and are reduced on the substrate surface, causing the metal to precipitate. As a result, a metal coating derived from the precipitated metal can be formed on the substrate surface. By applying such a voltage until the metal coating reaches a predetermined thickness, a metal coating of a desired thickness can be formed.

[0009] Finally, after the application operation is completed (i.e., after the application of the voltage for film formation is completed), the control device controls the lifting operation by the lifting device so as to separate the electrolyte membrane from the substrate, while controlling the pumping operation by the pumping device. This allows the electrolyte membrane to be separated from the substrate while supplying air between the substrate on which the metal coating is formed and the electrolyte membrane, so that the electrolyte membrane can be easily separated from the substrate while preventing the electrolyte membrane from adhering to the substrate and being stretched. In particular, when the electrolyte membrane is in contact with the substrate within the sealed space, the sealed space becomes a space depressurized by the suction device, but the pressure within the space can be increased by pumping air by the pumping device, thereby preventing the electrolyte membrane from adhering to the substrate.

[0010] In a more preferred embodiment, the film forming apparatus further includes an exchange mechanism for exchanging the plating solution contained in the container with the atmosphere, and the control device controls the exchange mechanism so that the plating solution is exchanged with the atmosphere after the application operation by the power supply unit is completed and before the control device starts to control the lifting operation by the lifting device so as to separate the electrolyte membrane from the substrate.

[0011] According to this aspect, the control device controls the replacing mechanism so that the plating solution is replaced with the atmosphere before starting the control of the lifting and lowering operation. With this control, the plating solution contained in the container is replaced with the atmosphere while the electrolyte membrane is in contact with the substrate, and then the electrolyte membrane is separated from the substrate, so that the electrolyte membrane can be prevented from being deformed by the weight of the plating solution. Furthermore, since the weight of the plating solution does not act on the electrolyte membrane, it becomes easier to cause air to enter between the electrolyte membrane and the substrate, and the electrolyte membrane can be easily separated from the substrate. Here, among the "air" referred to in this specification, the air to be sucked in refers to the air present between the electrolyte membrane and the substrate, and the air to be pumped refers to the air in the atmosphere that has been pressurized. The "atmosphere" for replacing the plating solution contained in the container refers to air at atmospheric pressure in the atmosphere.

[0012] This specification also discloses a method for forming a metal film as the present invention. 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 contained in the electrolyte film on the surface of the substrate by applying a voltage between an anode and a substrate serving as a cathode in a state where an electrolyte membrane contacted with a plating solution containing metal ions is brought into contact with the substrate, and is characterized by including the steps of: bringing the electrolyte membrane into contact with the substrate while sucking air present between the electrolyte membrane covering the opening formed in the container and the substrate arranged opposite the electrolyte membrane; applying a voltage between the anode and the substrate while the electrolyte membrane is brought into contact with the substrate until the metal film has a predetermined thickness, thereby forming the metal film; and separating the electrolyte membrane from the substrate while pumping air between the substrate on which the metal film has been formed and the electrolyte membrane.

[0013] According to the present invention, first, in a state where a plating solution is contained in a container, the electrolyte membrane covering an opening formed in the container and the substrate arranged opposite the electrolyte membrane are brought into contact with the substrate while the air between the electrolyte membrane and the substrate is sucked in by a suction device. As a result, air is prevented from being trapped between the electrolyte membrane and the substrate, and the electrolyte membrane can be tightly attached to the substrate.

[0014] Next, when a voltage is applied between the anode and the substrate with the electrolyte membrane in contact with the substrate, metal ions migrate to the surface side of the substrate through the electrolyte membrane and are reduced on the surface of the substrate, causing the metal to precipitate. As a result, a metal coating derived from the precipitated metal can be formed on the surface of the substrate. By applying such a voltage until the metal coating reaches a predetermined thickness, a metal coating of a desired thickness can be formed.

[0015] Finally, since the electrolyte membrane can be separated from the substrate while supplying air between the substrate on which the metal coating is formed and the electrolyte membrane, the electrolyte membrane can be easily separated from the substrate while preventing the electrolyte membrane from being attached to the substrate and being stretched. In particular, when the electrolyte membrane is in contact with the substrate in the sealed space, the sealed space is reduced in pressure by the suction device, but the pressure in the space can be increased by pumping air by the pumping device, thereby preventing the electrolyte membrane from being attached to the substrate.

[0016] A more preferred film forming method further includes a step of replacing the plating solution contained in the container with air after the step of forming the metal film and before the step of separating.

[0017] According to this aspect, after the plating solution contained in the container is replaced with air while the electrolyte membrane is in contact with the substrate, the electrolyte membrane is separated from the substrate, so that the electrolyte membrane can be prevented from being deformed by the weight of the plating solution. Furthermore, since the weight of the plating solution does not act on the electrolyte membrane, air can easily get in between the electrolyte membrane and the substrate, making it easier to separate the electrolyte membrane from the substrate. Effect of the Invention

[0018] According to the present invention, after the metal film is formed, the electrolyte membrane can be easily separated from the substrate while preventing the electrolyte membrane from being stretched. [Brief description of the drawings]

[0019] [Figure 1]1 is a schematic cross-sectional view of a metal film forming apparatus according to an embodiment of the present invention. [Diagram 2] 2 is a flowchart illustrating control of the film forming apparatus shown in FIG. [Diagram 3] 3 is a cross-sectional view for explaining the suction and contact step shown in FIG. 2 using the film forming apparatus shown in FIG. [Figure 4] 3 is a cross-sectional view for explaining the film forming process shown in FIG. 2 using the film forming apparatus shown in FIG. [Diagram 5] 3 is a cross-sectional view for explaining the replacement step shown in FIG. 2 using the film forming apparatus shown in FIG. [Figure 6] 3 is a cross-sectional view for explaining a pressure-feeding and separating step shown in FIG. 2 using the film forming apparatus shown in FIG. [Figure 7] FIG. 13 is a diagram illustrating the relationship between the elongation rate of an electrolyte membrane and the number of membrane formation operations using the membrane formation apparatuses of the examples and the comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a metal film forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[0021] 1, the film forming apparatus 1 includes an anode 11, an electrolyte membrane 13 disposed between the anode 11 and a substrate W, and a container 15 that contains the anode 11 and a plating solution L and has an opening 15g that opens toward the substrate W and is covered with the electrolyte membrane 13. The film forming apparatus 1 further includes a power supply unit 19 that applies a voltage between the anode 11 and the substrate W that serves as a cathode, a mounting table 20 on which the substrate W is placed, and a lifting device 70 that lifts and lowers the container 15.

[0022] In the film forming apparatus 1, while the electrolyte membrane 13 is brought into contact with the substrate W placed on the mounting table 20 by the lifting device 70, a voltage is applied between the anode 11 and the substrate W by the power supply unit 19 to form a metal coating on the surface wa of the substrate W. During film formation, metal ions contained inside the electrolyte membrane 13 from the plating solution L are reduced on the surface wa of the substrate W, and metal derived from the metal ions is precipitated, and a metal coating F is formed by the precipitated metal (see, for example, FIG. 5).

[0023] The substrate W functions as a cathode. The material of the substrate W is not particularly limited as long as it functions as a cathode (i.e., a surface having electrical conductivity), and may be made of a metal material such as aluminum or iron, or may be a resin, ceramic, or the like having a surface coated with a metal layer such as copper, nickel, silver, or iron.

[0024] The mounting table 20 is made of a conductive material and is disposed below the container 15 so that the substrate W faces the electrolyte membrane 13. The substrate (specifically, the cathode) W is electrically connected to the negative electrode of the power supply unit 19 via the mounting table 20. When the mounting table 20 is made of an insulating material, the negative electrode of the power supply unit 19 may be directly connected to the substrate W via a wire.

[0025] As described below, an air pump (pressure-feeding device) 51 is connected to the mounting table 20 via a pressure-feeding path 81, and a suction pump (suction device) 52 is connected to the mounting table 20 via a suction path 82. The air pump 51 is a device that pressure-feeds pressurized atmospheric air between the substrate W placed on the mounting table 20 and the electrolyte membrane 13, and the suction pump 52 is a device that sucks in air that exists between the substrate W placed on the mounting table 20 and the electrolyte membrane 13. The suction mechanism and pressure-feeding mechanism including the mounting table 20 will be described in detail below.

[0026] The anode 11 is attached to a container 15 described later so as to face the mounting table 20 (specifically, the substrate W), and is electrically connected to the positive electrode of the power supply unit 19 via a conductor or the like. The anode 11 has a shape corresponding to the film formation area of ​​the substrate W. The film formation area of ​​the substrate W is the surface wa of the substrate W facing the anode 11, which acts as a cathode. The anode 11 is a non-porous (for example, non-porous) anode made of the same metal as the metal coating, and is a block-shaped or flat anode. The anode 11 is made of the same metal as the metal coating, and may be soluble or insoluble in the plating solution L. However, as long as the required surface area is satisfied, the anode may be a porous anode, a mesh, or a metal ball laid out in a container.

[0027] When the anode 11 is soluble in the plating solution L, examples of the material include copper, nickel, silver, and tin. In the present embodiment, the material is not particularly limited as long as the anode 11 is dissolved by applying a voltage using the power supply unit 19. When the anode 11 is insoluble in the plating solution L, examples of the material include stainless steel, titanium, and titanium alloy.

[0028] As described above, the plating solution (electrolyte) L is a solution containing the metal of the metal film to be formed in an ion state, and examples of the metal include copper, nickel, silver, and tin. The plating solution L is an aqueous solution in which these 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 nickel, examples of the plating solution L include aqueous solutions of nickel nitrate, nickel phosphate, nickel succinate, nickel sulfate, nickel pyrophosphate, and nickel sulfamate. For example, when the metal is copper, examples of the plating solution L include aqueous solutions containing copper sulfate, copper pyrophosphate, and the like.

[0029] The electrolyte membrane (solid electrolyte membrane) 13 is a flexible membrane that can be impregnated (contained) with metal ions by contacting it with the above-mentioned plating solution L. The electrolyte membrane 13 is not particularly limited as long as it can reduce metal ions in the substrate W and precipitate metal derived from the metal ions when a voltage is applied from a power supply unit 19. 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 having an ion exchange function such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd.

[0030] As shown in FIG. 1, the container 15 is made of a material insoluble in the plating solution L, and the anode 11 and the electrolyte membrane 13 are attached to the container 15. In this embodiment, a storage space S for storing the plating solution L is formed inside the container 15 by the side wall of the container 15, the anode 11, and the electrolyte membrane 13. The anode 11 is attached to the inner surface of the container 15, and an opening 15g that opens to the side of the substrate W is formed at a position opposite the anode 11. The opening 15g opens downward, and the electrolyte membrane 13 is attached so as to seal the opening 15g. In this embodiment, the periphery of the electrolyte membrane 13 is sandwiched between the main body 15a and the frame 15b of the container 15, so that the electrolyte membrane 13 is attached to the container 15. The anode 11 and the electrolyte membrane 13 are arranged apart from each other and are in a non-contact state, and the storage space S formed between them is filled with the plating solution L during film formation. In this manner, the container 15 is structured so that the plating solution L contained in the container space S comes into direct contact with the anode 11 and the electrolyte membrane 13.

[0031] The container 15 is formed with a supply flow path 15c for supplying the plating solution L to the storage space S and a discharge flow path 15d for discharging the plating solution L from the storage space S. The supply flow path 15c and the discharge flow path 15d are in communication with the storage space S. Both the supply flow path 15c and the discharge flow path 15d are in communication with the storage space S near the electrolyte membrane 13.

[0032] The lifting device 70 is a device that lifts and lowers at least one of the container 15 and the mounting table 20 so that the electrolyte membrane 13 and the substrate W can be moved toward and away from each other. In this embodiment, the mounting table 20 is fixed and does not move, and the lifting device 70 lifts and lowers only the container 15. Specifically, as shown in FIG. 1 and FIG. 3, the lifting device 70 includes a device body 71 and a rod 72 that moves linearly relative to the device body 71, and the rod 72 is fixed to the upper part of the container 15. The lifting device 70 may be a known electric actuator that converts the rotation of a motor such as a servo motor into linear motion. As long as the electrolyte membrane 13 can be moved toward and away from the substrate W by linear motion, the lifting device 70 may be provided on the mounting table 20 or may be a hydraulic or pneumatic cylinder.

[0033] The following describes a circulation mechanism for circulating the plating solution L in the film forming apparatus 1, a suction mechanism and a pressure-feed mechanism including the mounting table 20, and the control device 60. The film forming apparatus 1 includes, as the circulation mechanism, a tank 17 connected to the accommodation body 15 for storing the plating solution L discharged from the accommodation body 15, and a pump 18 connected to the tank 17 for pressure-feeding the plating solution L from the tank 17 to the accommodation body.

[0034] The tank 17 is provided with an electric heating device 90 for heating the plating solution L. The heating device 90 is not particularly limited in terms of the heating method as long as it can heat the plating solution L to a predetermined temperature, and may be, for example, a steam heater. In this embodiment, the plating solution L contained in the tank 17 is heated by the heating device 90, and the heated plating solution L can be supplied from the tank 17 to the storage space S of the storage body 15 by the pump 18, so that the film formation speed of the metal film F can be increased. Note that, in this embodiment, the heating device is provided in the tank 17, but, for example, the heating device may be provided in the storage body 15 or in the supply path 87 between the tank 17 and the storage body 15 as long as a film can be formed using the plating solution L heated to a predetermined temperature. Note that the "path" in this embodiment refers to a flow path formed by piping through which the plating solution L or air in the atmosphere (i.e., the atmosphere) flows.

[0035] In this embodiment, the tank 17 is connected to the housing 15 via a supply path 87. A pump 18 is provided in the supply path 87, and the pump 18 is capable of rotating in both forward and reverse directions. When the pump 18 rotates in the forward direction, the plating solution L can be sent from the tank 17 to the housing 15, and when the pump 18 rotates in the reverse direction, the plating solution L can be sent from the housing 15 to the tank 17.

[0036] Discharge paths 83, 84 for returning the plating solution L discharged from the container 15 to the tank 17 are connected to the container 15. In this embodiment, a three-way valve 56 is provided between the discharge path 83 and the discharge path 84. In addition to the discharge paths 83, 84, an open path 85 open to the atmosphere is connected to the three-way valve 56. The three-way valve 56 has a first switching position for connecting the discharge paths 83, 84 and a second switching position for connecting the discharge path 83 and the open path 85. Each switching position of the three-way valve 56 is controlled by the control device 60.

[0037] 4, by rotating the pump 18 in the forward direction and controlling the three-way valve 56 to the first switching position, the plating solution L can be circulated while filling the container 15 with the plating solution L in the film forming apparatus 1. Specifically, the plating solution contained in the tank 17 is supplied to the container 15 by the pump 18 via a supply path 87, and the plating solution discharged from the container 15 is returned to the tank 17 via a discharge path 83 and a discharge path 84.

[0038] In this embodiment, for example, a pressure regulating valve (not shown) for regulating the liquid pressure of the plating solution L discharged from the container 15 may be provided in the discharge path 84. This allows the liquid pressure of the plating solution L contained in the container space of the container 15 to be adjusted to the pressure set by the pressure regulating valve.

[0039] 5, by controlling the pump 18 to rotate in the reverse direction and the three-way valve 56 to the second switching position, the plating solution L contained in the accommodation body 15 can be replaced with the atmosphere. Specifically, when the pump 18 rotates in the reverse direction with the three-way valve 56 in the second switching position, the atmosphere is sucked in from the release path 85 and flows into the accommodation body 15 via the discharge path 83, and the plating solution L contained in the accommodation body 15 is returned to the tank 17. As a result, the accommodation space S of the accommodation body 15 is filled with air (atmospheric air) at atmospheric pressure.

[0040] In this embodiment, the exchanging mechanism 50 is composed of the three-way valve 56, the open path 85, and the pump 18. However, the exchanging mechanism is not limited to such an apparatus mechanism, and may be a mechanism in which a drain hole is provided near the bottom of the container 15 and the plating solution L is discharged by the weight of the plating solution L. Alternatively, the exchanging mechanism may be a mechanism in which the air is pumped into the storage space S of the container 15 using the air pump 51 described later or another air pump. As long as the plating solution L can be replaced with the air in the container 15, the configuration of the exchanging mechanism is not particularly limited.

[0041] The mounting table 20 is formed with a recess 21 for accommodating the substrate W. In this embodiment, a gap is formed between the side wall of the recess 21 and the side surface of the substrate W. The mounting table 20 has a portion including the recess 21 protruding toward the housing 15 so that the surface wa of the substrate W enters the inside of the frame 15b of the housing 15 and is loosely fitted into the frame 15b when the surface wa of the substrate W is in contact with the electrolyte membrane 13. As a result, when the housing 15 is raised and lowered, the space including the substrate W and the electrolyte membrane 13 becomes a sealed space when the frame 15b is loosely fitted into the mounting table 20.

[0042] A flow path 22 is formed in the mounting table 20, and the flow path 22 communicates with the gap between the side wall of the recess 21 and the side surface of the substrate W. An air pump 51 is connected to the flow path 22. Specifically, a pressure-feeding path 81 is connected to the flow path 22, and the air pump 51 and an on-off valve 53 are provided in the pressure-feeding path 81 from the upstream side to the downstream side. As shown in FIG. 6, when the air pump 51 is started, the control device 60 opens the on-off valve 53, and compressed air is supplied to the flow path 22 through the pressure-feeding path 81. The air supplied to the flow path 22 flows through the gap between the side wall of the recess 21 and the side surface of the substrate W, and is pressure-feed between the substrate W and the electrolyte membrane 13 mounted on the mounting table 20. When the air pump 51 is driven, the on-off valve 55 provided in the flow path 22 is closed by the control device 60, and the on-off valve 54 described later may be opened by the control device 60.

[0043] In this embodiment, the suction pump 52 is connected to the flow path 22. Specifically, a suction path 82 different from the pressure-feed path 81 is connected to the flow path 22, and the suction path 82 is provided with an on-off valve 54 and a suction pump 52 from the upstream side to the downstream side. As shown in FIG. 6, when the suction pump 52 is started, the control device 60 opens the on-off valves 54 and 55, and the air between the electrolyte membrane 13 and the substrate W flows through the gap between the side wall of the recess 21 and the side surface of the substrate W, and is released to the atmosphere through the flow path 22 and the suction path 82. In this way, the suction pump 52 can suck the air between the electrolyte membrane 13 and the substrate W. Note that when the air pump 51 is driven, the on-off valve 53 of the pressure-feed path 81 may be closed by the control device 60.

[0044] The control device 60 controls the lifting operation by the lifting device 70, the suction operation by the suction pump 52, the application operation by the power supply unit 19, the replacement operation by the replacement mechanism 50 (specifically, the drive and rotation direction of the pump 18), and the pumping operation by the air pump 51, as well as the corresponding operations of the on-off valves 53-55 and the three-way valve 56. The application operation by the power supply unit 19 refers to the operation of a switch that applies a voltage by the power supply unit 19.

[0045] Although not shown, the control device 60 includes a storage device (not shown) that stores a control program for executing the following series of steps, and a computing device (not shown) that executes the control program. The storage device further stores set values ​​such as the start timing and drive time of the pump 18, the air pump 51, and the suction pump 52, the application start time and application time of the power supply unit 19, and the amount of displacement by the lifting device 70. The control device 60 receives inputs such as a signal from a pressure sensor (not shown) that measures the pressure in the storage space S of the storage body 15 via an input device or the like.

[0046] The control flow of the control device 60 will be described with reference to FIG. 2 below. The control device 60 performs the following series of operations. First, an installation step S1 is performed. Specifically, in this step, a transport device (not shown) and the like are controlled to install the substrate W on the mounting table 20. At this time, the alignment of the substrate W with respect to the anode 11 attached to the housing 15 is adjusted, and the temperature of the substrate W may be adjusted.

[0047] Next, the suction / contact step S2 is performed. Specifically, as shown in FIG. 3, the control device 60 controls the lifting operation by the lifting device 70 so that the substrate W contacts the electrolyte membrane 13, while controlling the suction operation by the suction pump 52. This control causes the electrolyte membrane 13 to contact the substrate W while sucking air present between the electrolyte membrane 13 covering the opening 15g of the housing 15 and the substrate W arranged opposite the electrolyte membrane 13. As a result, air is prevented from being trapped between the electrolyte membrane 13 and the substrate W, and the electrolyte membrane 13 can be tightly attached to the substrate W. In this state, the control device 60 stops the suction pump 52. In this state, the flow path 22 becomes negative pressure (relative to atmospheric pressure). At this stage, the control device 60 closes the on-off valves 53 to 55 as necessary.

[0048] Next, a liquid sending step S3 is performed. In this step, the control device 60 controls the driving of the pump 18 and controls the three-way valve 56 to the first switching position. As a result, as shown in Fig. 4, by driving the pump 18 in the forward direction, the plating solution L heated to a predetermined temperature by the heating device 90 in the tank 17 can be supplied from the supply path 87 to the accommodation space S of the accommodation body 15 and returned to the tank 17 via the discharge paths 83 and 84.

[0049] Here, if the liquid pressure of the plating solution L contained in the containing space S can be maintained at a predetermined pressure by the above-mentioned pressure regulating valve, the control device 60 may continuously drive the pump 18 even during film formation. Also, an on-off valve (not shown) may be provided in the discharge path 83, and the control device 60 may close the on-off valve and stop the pump 18 at a stage where the predetermined pressure is maintained.

[0050] Next, a film-forming step S4 is performed. In this step, the control device 60 controls the application operation by the power supply unit 19 after the substrate W comes into contact with the electrolyte membrane 13 until the metal coating F reaches a predetermined thickness. Specifically, when a voltage is applied between the anode 11 and the substrate W in a state in which the electrolyte membrane 13 is in contact with the substrate W, metal ions move to the surface side of the substrate W through the electrolyte membrane 13 and are reduced on the surface wa of the substrate W, whereby the metal is precipitated and the metal coating F is formed. By applying such a voltage until the metal coating F reaches a predetermined thickness, the metal coating F can be formed to a desired thickness.

[0051] Next, a replacement step S5 is performed. In this step, the control device 60 controls the replacement mechanism 50 (specifically, the pump 18 and the three-way valve 56) so that the plating solution L is replaced with the atmosphere. Specifically, the control device 60 switches the three-way valve 56 to the second switching position and reversely rotates the pump 18, so that the plating solution L in the storage space S of the storage body 15 is returned to the tank 17 via the supply path 87, as shown in FIG. 5. At the same time, the atmosphere is introduced into the release path 85, and the introduced atmosphere is supplied to the storage space S of the storage body 15 via the discharge path 83. When almost all of the plating solution L is discharged from the storage space S, the control device stops the pump 18. Note that FIG. 5 shows a stage in the middle of replacing the plating solution L contained in the storage space with the atmosphere.

[0052] Next, a pressure-feeding / separation step S6 is performed. Specifically, as shown in Fig. 6, the control device 60 controls the lifting operation by the lifting device 70 so as to separate the substrate W from the electrolyte membrane 13, while controlling the pressure-feeding operation by the air pump 51. With this control, air is pressure-feeded between the substrate W on which the metal film F is formed and the electrolyte membrane 13, and the electrolyte membrane 13 is separated from the substrate W. Specifically, the air pressure-feeded by the air pump 51 flows through the flow path 22 via the pressure-feeding path 81, is forced into the gap between the electrolyte membrane 13 and the substrate W, then flows through the flow path 22, and is discharged from the suction pump 52 via the suction path 82.

[0053] In this embodiment, in order to form such a flow, the control device 60 closes the on-off valve 55 and drives the suction pump 52 so that the flow path 22 does not become negative pressure (preferably positive pressure). However, if air can be caused to flow between the electrolyte membrane 13 and the substrate W, the suction pump 52 may not be driven and the air exhausted from the suction path 82 upstream of the suction pump 52 may be released into the atmosphere.

[0054] Finally, a removal step S7 is performed. In this step, since the substrate W and the container 15 are in the positional relationship shown in Fig. 1, a conveying device (not shown) and the like are controlled to remove the substrate W from the mounting table 20. When forming a metal coating on a new substrate W, this series of steps is repeated.

[0055] According to this embodiment, as described above, in the pressure-feeding / separating step S6, the electrolyte membrane 13 is separated from the substrate W while pressure-feeding air between the electrolyte membrane 13 on which the metal film F is formed and the substrate W. This makes it possible to easily separate the electrolyte membrane 13 from the substrate W while preventing the electrolyte membrane 13 from being attached to the substrate W and being stretched. In particular, in this embodiment, since the electrolyte membrane 13 is in contact with the substrate W in the sealed space, the sealed space becomes a space depressurized by the suction pump 52 in the suction / contact step S2, but the pressure in the space is increased by pressure-feeding air by the air pump 51 in the pressure-feeding / separating step S6, and it is possible to prevent the electrolyte membrane 13 from being attached to the substrate W.

[0056] Furthermore, in the replacing step S5, the plating solution L contained in the container 15 is replaced with air while the electrolyte membrane 13 is in contact with the substrate W, and then the electrolyte membrane 13 is separated from the substrate W, so that it is possible to prevent the electrolyte membrane 13 from being deformed due to the weight of the plating solution L. Furthermore, since the weight of the plating solution L does not act on the electrolyte membrane 13, it becomes easier to cause air to enter between the electrolyte membrane 13 and the substrate W in the pressure-feeding and separation step S6, and the electrolyte membrane 13 becomes easier to separate from the substrate W. EXAMPLES

[0057] The invention is illustrated by the following examples.

[0058] [Example] As a substrate on whose surface a film was formed, a copper block substrate having a film formation area of ​​18 mm×35 mm and a thickness of 3 mm was prepared.

[0059] Next, a nickel film was formed using the film-forming apparatus shown in FIG. 1. A 1M nickel chloride + nickel acetate aqueous solution (pH 4.0) was prepared as the plating solution, and a nickel anode was used as the anode. The film-forming conditions were as follows: the temperature of the plating solution was 60°C, an electrolyte membrane (Nafion (registered trademark): manufactured by DuPont) was attached to the substrate, the liquid pressure of the plating solution was 1.0 MPa, and the current density was 15 A / dm 2 The current was passed for 3 minutes and 20 seconds to form a nickel film. This process was repeated several times according to the flow shown in Figure 2.

[0060] [Comparative Example] A nickel coating was formed in the same manner as in Example 1. The difference from Example 1 was that the pressure-feeding and separating step S6 shown in FIG.

[0061] <Confirmation of the elongation rate of the electrolyte membrane> The elongation of the electrolyte membrane after repeated membrane formation was measured using the membrane formation apparatuses of the Examples and Comparative Examples. The results are shown in Figure 7. Figure 7 is a diagram illustrating the relationship between the elongation of the electrolyte membrane and the number of membrane formations using the membrane formation apparatuses of the Examples and Comparative Examples.

[0062] 7, when a nickel coating was formed using the film-forming apparatus of the embodiment, for the reasons described above, the electrolyte membrane hardly stretched compared to the membrane before the film formation, even after the number of film formation cycles exceeded 90. However, in the comparative example in which the pumping and separating steps were not performed, the electrolyte membrane underwent plastic deformation and stretched by about 16% after only a few film formation cycles.

[0063] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims.

[0064] In this embodiment, the film forming method is performed under the control of a control device. However, for example, the series of operations shown in FIG. 2 may be performed manually without being controlled by a control device, or a part of the operations may be performed by a control device. [Explanation of symbols]

[0065] 1: film forming device, 11: anode, 13: electrolyte membrane, 15: container, 15g: opening, 17: tank, 19: power supply unit, 20: mounting table, 50: replacement mechanism, 51: air pump (pumping device), 52: suction pump (suction device), 60: control device, 70: lifting device, W: substrate, L: plating solution

Claims

1. An anode; an electrolyte membrane disposed between the anode and a substrate; a container that contains the anode and the plating solution and has an opening that opens to the substrate side and is covered with the electrolyte membrane; A power supply unit that applies a voltage between the anode and the base material that serves as a cathode, A film forming apparatus for forming a metal film derived from metal ions in the plating solution on a surface of the substrate by applying the voltage while an electrolyte membrane is in contact with the substrate, the film forming apparatus comprising: The film forming apparatus includes: A mounting table on which the base material is placed; a lifting device that lifts and lowers at least one of the container and the stage so that the electrolyte membrane can be brought into contact with and separated from the base material; a suction device that sucks air present between the substrate placed on the mounting table and the electrolyte membrane; a pressure-feeding device that pressurizes air between the substrate placed on the mounting table and the electrolyte membrane; A control device that controls the lifting operation by the lifting device, the suction operation by the suction device, the application operation by the power supply unit, and the pumping operation by the pumping device, The control device includes: controlling a lifting operation by the lifting device so that the base material comes into contact with the electrolyte membrane, while controlling a suction operation by the suction device; After the base material comes into contact with the electrolyte membrane, the application operation by the power supply unit is controlled until the metal coating reaches a predetermined thickness; a pressure-feeding operation by the pressure-feeding device is controlled while controlling a lifting operation by the lifting device so that the electrolyte membrane is separated from the substrate after the application operation is completed.

2. The film forming apparatus further includes a replacement mechanism that replaces the plating solution contained in the container with air, The metal film forming apparatus according to claim 1, characterized in that the control device controls the replacement mechanism so that the plating solution is replaced with air between the end of the application operation by the power supply unit and the start of control of the lifting operation by the lifting device so as to separate the electrolyte membrane from the substrate.

3. A film formation method for forming a metal coating derived from the metal ions contained in the electrolyte membrane on a surface of the substrate by applying a voltage between an anode and the substrate serving as a cathode in a state in which an electrolyte membrane, which has been in contact with a plating solution containing metal ions, is brought into contact with the substrate, the method comprising the steps of: a step of bringing the electrolyte membrane into contact with the base material while sucking air present between the electrolyte membrane covering the opening formed in the container and the base material disposed opposite the electrolyte membrane; applying a voltage between the anode and the substrate while the electrolyte membrane is in contact with the substrate, until the metal coating reaches a predetermined thickness, thereby forming the metal coating; and separating the electrolyte membrane from the substrate while pumping air between the substrate on which the metal film is formed and the electrolyte membrane.

4. 4. The method for forming a metal film according to claim 3, further comprising the step of replacing the plating solution contained in the container with air after the step of forming the metal film and before the step of separating.

Images