Metal-coated film forming apparatus and metal-coated film forming method

Abstract

Provided is a metal-coated film forming apparatus and a metal-coated film forming method. By inhibiting electrolyte from remaining between a solid electrolyte film and a substrate, homogeneous metal-coated film formation is possible. The metal-coated film forming apparatus has at least: an anode; a solid electrolyte film disposed between the anode and a substrate; a power supply section that connects current between the anode and the substrate; a placement table that has a housing recess corresponding to the shape of the substrate, and that places the substrate by housing the substrate in the housing recess; and a housing that forms a housing chamber that houses electrolyte together with the anode, and that has the solid electrolyte film installed in a manner that seals the housing chamber, and that has a drain section that drains electrolyte that has passed through the solid electrolyte film from a position that opposes the end surface of the side wall of the housing.

Description

TECHNICAL FIELD

[0001] The present application relates to a film forming apparatus and a film forming method for forming a metal film on a surface of a substrate by causing a metal derived from a metal ion to deposit on the surface of the substrate. BACKGROUND

[0002] For example, in Patent Literature 1, a film forming apparatus provided with an anode, a solid electrolyte film disposed between the anode and a substrate that is a cathode, a power supply portion that connects electric current between the anode and the substrate, and a placement table on which the substrate is placed is proposed. A housing recess that houses the substrate is formed in the placement table of the film forming apparatus, and a suction portion that suctions in such a manner that the solid electrolyte film is in close contact with the surface of the substrate is provided on the bottom surface of the housing recess.

[0003] The suction portion has a suction port formed on the bottom surface of the housing recess, and by suctioning the solid electrolyte film from the suction port, the surface of the substrate is pressed with the solid electrolyte film, and in this state, electric current is connected between the anode and the substrate, thereby causing a metal film to be formed on the surface of the substrate.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2016-169399 SUMMARY

[0007] However, when film formation is performed with the solid electrolyte film, along with the permeation of the metal ion through the solid electrolyte film, the electrolyte solution sometimes permeates to the substrate side through the solid electrolyte film. When film formation is performed, the substrate is pressed with the solid electrolyte film, so it is assumed that the electrolyte solution that permeates to the substrate side is retained between the solid electrolyte film and the substrate. Due to such retention of the electrolyte solution, it is difficult for the metal of the metal ion to deposit on the surface of the substrate, and sometimes it is not possible to perform film formation of a homogeneous metal film.

[0008] Therefore, for example, in the case of using the film forming apparatus shown in Patent Literature 1, it is considered that the retained electrolyte solution is discharged from the gap between the side surface of the housing recess that houses the substrate and the side surface of the substrate. However, the gap from which the electrolyte solution is discharged is opposed to the solid electrolyte film with the electrolyte solution in between, so the solid electrolyte film that is opposed to this gap is easily deformed, and when the electrolyte solution is discharged at the time of film formation, there is a possibility that the solid electrolyte film also deforms and enters into this gap along with the flow of the electrolyte solution. As a result, at the time of film formation, it is difficult to sufficiently discharge the electrolyte solution that is retained between the solid electrolyte film and the substrate, and there is a possibility that the solid electrolyte film is also damaged.

[0009] The present application was completed in view of such a problem point, and as the present application, a film forming apparatus and a film forming method that enable film formation of a homogeneous metal film by suppressing retention of an electrolyte solution between a solid electrolyte film and a substrate are provided.

[0010] In view of the problem, the metal film forming apparatus according to the present application is characterized by at least including: an anode; a solid electrolyte film disposed between the anode and a substrate that is a cathode; a power supply section that applies a current between the anode and the substrate; a placement table that places the substrate; and a housing that forms, together with the anode, a housing chamber that houses an electrolyte solution, and the solid electrolyte film is installed in a manner to seal the housing chamber, and in a state where the solid electrolyte film presses the substrate with the hydraulic pressure of the electrolyte solution passing through the housing chamber, the current is applied, and metal ions included in the electrolyte solution cause a metal film to be formed on the surface of the substrate, wherein a drain section that drains the electrolyte solution that has passed through the solid electrolyte film from a position opposite to an end surface of a side wall of the housing is provided in the placement table.

[0011] According to the present application, a voltage can be applied between the anode and the substrate in a state where the solid electrolyte film presses the surface of the substrate with the hydraulic pressure of the electrolyte solution passing through the housing chamber, and metal ions included in the electrolyte solution housed in the housing chamber pass through the solid electrolyte film, and metal is deposited on the surface of the substrate. Thus, a metal film can be formed on the surface of the substrate.

[0012] Here, according to the present application, the drain section that drains the electrolyte solution that has passed through the solid electrolyte film from a position opposite to an end surface of a side wall of the housing is provided in the placement table. Thus, the electrolyte solution housed in the housing chamber is not present at a position opposite to the drain section with the solid electrolyte film interposed therebetween, and the electrolyte solution is not drained from a position opposite to a portion of the solid electrolyte film that is likely to deform. As a result, the solid electrolyte film does not deform in a manner to block the drain section due to the hydraulic pressure of the electrolyte solution, the flow of the electrolyte solution, or the like, and damage to the solid electrolyte film is prevented and the electrolyte solution that has passed through the solid electrolyte film is easily drained through the drain section. In this way, according to the present application, the electrolyte solution that remains between the solid electrolyte film and the substrate can be drained, and a metal film can be formed uniformly.

[0013] Here, the drain section can have a plurality of drain openings. However, as a more preferable mode, a housing recess that corresponds to the shape of the substrate is formed in the placement table, and the drain section has a drain groove that is formed in a manner to surround the housing recess at intervals from the periphery of the housing recess as a recess for placement.

[0014] According to this mode, the drain groove is provided around the substrate housed in the housing recess when the metal film is formed, and thus the electrolyte solution that flows out between the solid electrolyte film and the substrate can be drained more uniformly from around the substrate.

[0015] Further, if the electrolyte is discharged from between the solid electrolyte membrane and the base material to the discharge portion by the solid electrolyte membrane for hydraulic pressure of the electrolyte, the electrolyte can be discharged without being sucked. However, as a more preferable mode, the discharge portion is connected to a suction pump that sucks the electrolyte from the discharge portion.

[0016] According to this mode, by generating negative pressure in the discharge portion by the suction pump, the electrolyte can be efficiently sucked from between the solid electrolyte membrane and the base material and discharged to the outside of the film forming device via the discharge portion.

[0017] Here, in the case where the suction pump is provided, the suction pump can be continuously operated from the timing at which the film formation is started to the timing at which the film formation is ended. However, as a more preferable mode, the power supply portion supplies electric current to be connected between the anode and the base material in such a manner that the electric current to be connected between the anode and the base material is kept constant at the time of film formation of the metal coating film, and the film forming device further includes a voltage meter that measures the voltage between the anode and the base material, and a control device that controls the start and stop of the suction pump, the control device causing the suction pump to start when the voltage measured by the voltage meter becomes equal to or higher than a predetermined voltage value at the time of film formation, and causing the suction pump to stop after a predetermined set time elapses from the start of the suction pump.

[0018] At the time of film formation, in the case where the electrolyte that has passed through the solid electrolyte membrane is retained between the solid electrolyte membrane and the base material, the metal ions of the electrolyte are consumed in the film formation, so the voltage between the anode and the base material increases. Therefore, at the time of film formation of the metal coating film, when the voltage between the anode and the base material becomes equal to or higher than a predetermined voltage value, it can be determined that a sufficient amount of electrolyte is retained between the solid electrolyte membrane and the base material. Therefore, according to this mode, the control device can cause the suction pump to start at such a timing, and forcibly discharge the sucked electrolyte while sucking the retained electrolyte from the start to after a predetermined set time elapses. In this way, by effectively starting and stopping the suction pump, the electrolyte retained between the solid electrolyte membrane and the base material can be efficiently sucked by the suction pump, and the film formation of the metal coating film can be performed uniformly.

[0019] The metal film forming method according to the present application is characterized in that, in a state where a substrate is pressed by a solid electrolyte membrane for hydraulic pressure of an electrolyte solution accommodated in an accommodation chamber, electric current is applied between an anode and the substrate serving as a cathode, and a metal film is formed on a surface of the substrate from metal ions contained in the electrolyte solution, the method includes: a step of placing the substrate on a placement table; a step of bringing the solid electrolyte membrane into contact with the substrate placed on the placement table and pressing the substrate by the solid electrolyte membrane for hydraulic pressure; and a step of applying electric current between the anode and the substrate in a state where the substrate is pressed by the solid electrolyte membrane, thereby forming the metal film on the substrate, in which the electrolyte solution that has passed through the solid electrolyte membrane is drained from a position on a surface of the placement table that is opposite to an end surface of a side wall of a housing that forms the accommodation chamber.

[0020] According to the present application, in the step of forming the metal film, a voltage is applied between the anode and the substrate in a state where the surface of the substrate is pressed by the solid electrolyte membrane for hydraulic pressure of the electrolyte solution accommodated in the accommodation chamber. Thus, the metal ions contained in the electrolyte solution accommodated in the accommodation chamber can be made to pass through the solid electrolyte membrane and cause the metal to deposit on the surface of the substrate. As a result, the metal film can be formed on the surface of the substrate.

[0021] Further, according to the present application, in the step of forming the metal film, the electrolyte solution that has passed through the solid electrolyte membrane is drained from a position on a surface of the placement table that is opposite to an end surface of a side wall of a housing. Thus, the electrolyte solution accommodated in the accommodation chamber is not present at a portion between the solid electrolyte membrane and the position from which the electrolyte solution is drained. As a result, the solid electrolyte membrane does not deform in a manner that blocks the portion from which the electrolyte solution is drained, so damage to the solid electrolyte membrane is avoided, and the electrolyte solution that has passed through the solid electrolyte membrane can be easily drained. Thus, according to the present application, the electrolyte solution that remains between the solid electrolyte membrane and the substrate can be drained, and the formation of a uniform metal film can be performed.

[0022] Here, a plurality of drain ports can be provided around the accommodation recess, and the electrolyte solution can be drained from the drain ports. However, as a more preferable mode, the placement table is formed with an accommodation recess corresponding to the shape of the substrate, and a drain groove that is spaced apart from the periphery of the accommodation recess and surrounds the accommodation recess, the substrate is placed on the placement table in such a manner that the substrate is accommodated in the accommodation recess in the step of placing, and the electrolyte solution is drained through the drain groove in the step of forming the metal film.

[0023] According to this mode, when the metal film is formed, the drain groove is provided around the substrate accommodated in the accommodation recess, so the electrolyte solution that flows out between the solid electrolyte membrane and the substrate can be more uniformly drained from around the substrate.

[0024] Further, if the electrolyte can be discharged by ejecting the electrolyte from between the solid electrolyte membrane and the base material using the solid electrolyte membrane for hydraulic pressure, the electrolyte can be discharged without attracting the electrolyte. However, as a more preferable method, in the process of forming the membrane, the discharge is performed while the electrolyte is attracted by the suction pump.

[0025] According to this method, the electrolyte can be efficiently sucked from between the solid electrolyte membrane and the base material by the negative pressure generated by the suction pump, and discharged to the outside of the membrane forming apparatus from a position opposite to the end surface of the side wall of the housing.

[0026] Here, in the case where the suction pump is provided, the suction pump can be continuously operated from the timing at which the membrane formation is started to the timing at which the membrane formation is ended. However, as a more preferable method, in the process of forming the membrane, the voltage between the anode and the base material is measured while the current is kept constant, and when the measured voltage becomes equal to or higher than a predetermined voltage value, the electrolyte is attracted using the suction pump, and after a predetermined set time elapses from the start of the attraction, the attraction using the suction pump is stopped.

[0027] According to this method, when the voltage between the anode and the base material becomes equal to or higher than a predetermined voltage value, it can be determined that a sufficient amount of electrolyte is retained between the solid electrolyte membrane and the base material. Therefore, the suction pump can be activated at such a timing, and from the activation to the elapse of a predetermined set time, the retained electrolyte is forcibly discharged while being attracted. In this way, by effectively activating and stopping the suction pump, the electrolyte retained between the solid electrolyte membrane and the base material can be efficiently sucked by the suction pump, and the formation of a homogeneous metal coating film can be performed.

[0028] According to the membrane forming apparatus and the membrane forming method of the present application, by inhibiting the retention of the electrolyte between the solid electrolyte membrane and the base material, the formation of a homogeneous metal coating film can be performed. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic cross-sectional view illustrating a state in which a base material is placed on a membrane forming apparatus relating to a metal coating film according to an embodiment of the present application.

[0030] Figure 2 is a view of a placement table of the membrane forming apparatus shown in Figure 1 from the housing side.

[0031] Figure 3 is a flowchart illustrating a process of a membrane forming method of a metal coating film using the membrane forming apparatus shown in Figure 1

[0032] Figure 4 is a flowchart illustrating a process of a membrane forming method of a metal coating film using the membrane forming apparatus shown in Figure 3 ​A schematic conceptual diagram of a film formation process of a metal coating film.

[0033] Figure 5 is a photograph showing Figure 1 A schematic cross-sectional view of a modification of the film formation apparatus.

[0034] Figure 6 is a photograph showing Figure 5 A control flowchart of the control apparatus.

[0035] Figure 7A is a photograph showing the appearance after film formation observed for a test body relating to the embodiment.

[0036] Figure 7B is a photograph showing the appearance after film formation observed for a test body relating to the comparative example.

[0037] Figure 8 is a graph showing the change in voltage accompanying the passage of time in relation to the film formation relating to the embodiment.

[0038] Figure 9 is a schematic cross-sectional view showing a state in which a curved portion is generated in the solid electrolyte film in the film formation apparatus that is the subject of comparison and the solid electrolyte film is deformed in a manner that it departs from the substrate.

[0039] (Symbol explanation)

[0040] 1: Film formation apparatus; 11: Anode; 12: Solid electrolyte film; 13: Power supply portion; 14: Housing; 14a: Accommodation chamber; 14b: Side wall; 14c: End face; 15: Placement table; 15a: Accommodation recess; 15b: Periphery; 30: Drain portion; 31: Drain groove; 41: Suction pump; 50: Voltmeter; 60: Control apparatus; F: Metal coating film; S: Electrolytic solution; W: Substrate. DETAILED DESCRIPTION

[0041] Hereinafter, referring to Figures 1-9 , an embodiment relating to the present application and a modification thereof will be described.

[0042] 1. Configuration of the film formation apparatus 1

[0043] Referring to Figure 1 and Figure 2, describing the film forming device 1 for forming a metal coating according to the present embodiment. The film forming device 1 of the present embodiment is a film forming device (plating device) for forming a metal coating by a solid phase electrolysis method using a solid electrolyte membrane. The film forming device 1 is used when a metal coating F is formed (formed) on the surface of the substrate W using the substrate W as a cathode. The film forming device 1 can also be used when a metal coating F is continuously formed on the surfaces of multiple substrates W. The substrate W serving as the cathode can be a substrate made of a metal material such as copper, nickel, silver, or gold, or a substrate having a metal base layer of copper, nickel, silver, or gold formed on the surface of a resin, ceramic, or the like. When the metal coating is formed, the metal base layer is connected to the negative electrode of the power supply unit 13 described later and serves as a cathode.

[0044] like Figure 1 As shown, the film forming apparatus 1 includes an anode 11, a solid electrolyte membrane 12 disposed between the anode 11 and the substrate W, and a power supply unit 13 for supplying current between the anode 11 and the substrate W. The film forming apparatus 1 further includes a housing 14 having a storage chamber 14a for storing an electrolyte S, and a mounting table 15 for mounting the substrate W.

[0045] In this embodiment, the anode 11 is electrically connected to the positive electrode of the power supply unit 13, and the mounting table 15 is electrically connected to the negative electrode of the power supply unit 13. As described later, the mounting table 15 is made of a conductive material, so that the substrate W is electrically connected to the negative electrode of the power supply unit 13. As a result, the power supply unit 13 can pass current between the anode 11 and the substrate W while the solid electrolyte membrane 12 is in contact with the surface of the substrate W.

[0046] In this embodiment, the anode 11 is, for example, a plate-shaped metal plate, and can be any of a soluble anode made of the same material as the metal coating F (such as Cu) or an anode made of a material insoluble in the electrolyte S (such as Ti).

[0047] The solid electrolyte membrane 12 can be impregnated with (contain) metal ions by contacting the electrolyte S. There are no particular limitations as long as a metal derived from the metal ions can be deposited on the surface of the cathode (substrate W) when power is applied between the anode 11 and the cathode.

[0048] The solid electrolyte membrane 12 is set to a thickness that allows flexibility due to the hydraulic pressure of the electrolyte S described later. The thickness of the solid electrolyte membrane 12 is preferably 1 μm to 200 μm, for example. Examples of materials for the solid electrolyte membrane 12 include fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins having a cation exchange function such as Selemion (CMV, CMD, and CMF series) manufactured by Asahi Glass Co., Ltd.

[0049] The electrolyte S is a liquid containing the metal of the metal coating film F in an ionic state, and as the metal, Cu, Ni, Zn, Ag, Sn, or Au, or the like can be given. The electrolyte S is obtained by dissolving these metals (ionization) with an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, or pyrophosphoric acid.

[0050] In the present embodiment, the case 14 is composed of a material that is insoluble with respect to the electrolyte S. The case 14 is formed together with the anode 11 with a housing chamber 14a that houses the electrolyte S. The solid electrolyte membrane 12 is installed in a manner that seals the housing chamber 14a that is open downward. Specifically, the anode 11 is disposed apart from the solid electrolyte membrane 12 in the housing chamber 14a, and the electrolyte S is housed in a manner that contacts the anode 11 and the solid electrolyte membrane 12.

[0051] In the present embodiment, an insertion groove 14d into which the sealing material 17 is inserted in a state that the periphery of the solid electrolyte membrane 12 is bent is formed in the end surface 14c of the side wall 14b of the case 14. The insertion groove 14d is formed in a manner that surrounds the opening of the housing chamber 14a. The sealing material 17 is inserted into the insertion groove 14d in a state that the periphery of the solid electrolyte membrane 12 is bent, and the periphery of the solid electrolyte membrane 12 is pressed by the sealing material 17 that elastically deforms, whereby the housing chamber 14a that is open downward can be sealed with the solid electrolyte membrane 12.

[0052] The case 14 is formed with a supply port 14e that supplies the electrolyte S, and a discharge port 14f that discharges the electrolyte S. The supply port 14e and the discharge port 14f are connected to the tank 21 via a pipe. A pressure feeding pump 22 that pressure-feeds the electrolyte S of the tank 21 is provided between the tank 21 and the supply port 14e. Thereby, the electrolyte S that is fed from the tank 21 through the pressure feeding pump 22 can flow into the housing chamber 14a from the supply port 14e, the electrolyte S that flows in can be discharged from the discharge port 14f, and the electrolyte S that is discharged can be returned to the tank 21.

[0053] Further, in the present embodiment, a pressure adjusting valve 23 is provided on the downstream side of the discharge port 14f, and the electrolyte S in the housing chamber 14a can be pressurized at a predetermined pressure by the pressure adjusting valve 23 and the pressure feeding pump 22. In this way, at the time of film formation, the substrate W that contacts the solid electrolyte membrane 12 can be pressed by the solid electrolyte membrane 12 by the hydraulic pressure of the electrolyte S (refer to Figure 4 ). Thereby, the metal coating film F can be formed on the substrate W while the substrate W is uniformly pressurized by the solid electrolyte membrane 12. In addition, in the present specification, the pressure adjusting valve 23 and the pressure feeding pump 22 are referred to as a pressurizing mechanism.

[0054] The stage 15 is formed with a housing recess 15a corresponding to the shape of the substrate W. The housing recess 15a is a recess for placing the substrate W, and the substrate W is placed by being housed in the housing recess 15a. In the present embodiment, as one example thereof, it is preferable that no gap be present between the side wall surface of the housing recess 15a and the side surface of the substrate W in a state in which the substrate W is housed in the housing recess 15a, and it is more preferable that the surface of the stage 15 and the surface of the substrate W be formed on the same plane.

[0055] As a result, the electrolyte solution S that has permeated the solid electrolyte membrane 12 easily flows from between the solid electrolyte membrane 12 and the substrate W to the liquid discharge portion 30 described later. However, even if a gap is present between the side wall surface of the housing recess 15a and the side surface of the substrate W, when the gap is filled with the electrolyte solution S that has permeated the solid electrolyte membrane 12, the electrolyte solution S that further permeates the solid electrolyte membrane 12 easily flows to the liquid discharge portion 30. Therefore, as described later, the electrolyte solution S is difficult to remain between the solid electrolyte membrane 12 and the substrate W. Furthermore, if the electrolyte solution S that remains between the solid electrolyte membrane 12 and the metal film F can be discharged, the housing recess 15a can not be provided in the stage 15.

[0056] In the present embodiment, the film formation apparatus 1 further includes a lifting device 16 connected to the upper portion of the housing 14. The lifting device 16 is a device that can lift the housing 14 in a range from a position at which the substrate W and the solid electrolyte membrane 12 are separated to a position at which the solid electrolyte membrane 12 contacts the substrate W. The lifting device 16 is not limited in detail if it can lift the housing 14, and can be constituted by, for example, a hydraulic or pneumatic cylinder, an electric actuator, a linear slide, a motor, or the like.

[0057] However, at the time of film formation of the metal film F, metal ions move within the solid electrolyte membrane 12 in a state in which they are coordinated with water molecules, and the metal ions that have moved to the substrate W side are reduced (are given electrons) on the surface of the substrate W and are deposited as metal. Due to the movement of the metal ions at the time of film formation, the electrolyte solution S permeates the solid electrolyte membrane 12, and the electrolyte solution S that has permeated is consumed by film formation of the metal ions, and thus the solvent included in the electrolyte solution S sometimes remains between the substrate W and the solid electrolyte membrane 12. Here, the "electrolyte solution that has permeated the solid electrolyte membrane" referred to in the present application is strictly speaking a liquid that is different in composition from the liquid included in the housing chamber 14a, which is due to the electrolyte solution that has permeated as a result of the movement of the metal ions.

[0058] As a result, as Figure 9As shown, in the film formation device 90 that is a comparative example, the electrolyte S housed in the housing chamber 94a of the housing 94 passes through the solid electrolyte film 92 at the time of energization between the anode 11 and the substrate W. The electrolyte S that has passed through the solid electrolyte film 92 is retained between the solid electrolyte film 92 and the substrate W. The retained electrolyte S is consumed by metal ions, and the component of the solvent of the electrolyte S becomes excessive, so the electrolyte S sometimes functions as a resistance at the time of film formation. When the amount of the retained electrolyte S increases in this way, the solid electrolyte film 92 is deformed away from the substrate W due to the retained electrolyte, and a large gap is formed between the solid electrolyte film 92 and the surface of the substrate W at the time of film formation. As a result, the metal of the metal ions is difficult to deposit on the surface of the substrate W, and sometimes the film formation of a homogeneous metal film cannot be performed.

[0059] Here, in Figure 9 As shown, in the film formation device 90, the housing recess 95a that houses the substrate W is provided on the placement stage 95 on which the substrate W is placed, and the drain 96 that drains the electrolyte S through the gap 97 including the side surface of the substrate W and the side wall surface of the housing recess 95a is provided. However, when the drain 96 including the gap 97 generates a flow of the electrolyte S to be drained, the solid electrolyte film 92 sometimes enters the gap 97, and a curved portion 98 is formed. Thus, the drainability of the electrolyte S that is retained between the solid electrolyte film 92 and the substrate W is hindered, and there is a possibility that the curved portion 98 of the solid electrolyte film 92 is damaged.

[0060] In view of such a problem point, in the present embodiment, the drain 30 that drains the electrolyte S that has passed through the solid electrolyte film 12 is provided on the placement stage 15. The drain 30 drains the electrolyte S that has passed through the solid electrolyte film 12 from a position opposite to the end surface 14c of the side wall 14b of the housing 14 that forms the housing chamber 14a. That is, the drain 30 drains the electrolyte S that has passed through the solid electrolyte film 12 from a position deviated from the housing chamber 14a.

[0061] In the present embodiment, as Figure 1 and Figure 2 As shown, the drain 30 has a drain groove 31 and a drain passage 32 that communicates with the drain groove 31. The drain groove 31 is formed on the surface of the placement stage 15 at a position deviated from the housing recess 15a (specifically, a position opposite to the end surface 14c of the side wall 14b of the housing 14).

[0062] In the present embodiment, as Figure 2As shown, the drain groove 31 is formed so as to surround the receiving recess 15a at a distance from the peripheral edge 15b of the receiving recess 15a. The drain groove 31 is connected to the drain passage 32 via the connecting portion 32a. The drain groove 31 may also be inclined so as to allow the electrolyte S to flow toward the connecting portion 32a of the drain passage 32. In the present embodiment, the drain passage 32 is formed inside the mounting table 15. In the present embodiment, there is one connecting portion 32a, but a plurality of connecting portions connecting the drain groove 31 and the drain passage 32 may be provided so that the electrolyte S flowing into the drain groove 31 is drained from the plurality of connecting portions.

[0063] In addition, in this embodiment, if Figure 1 As shown, the drain groove 31 is formed at a position opposite the sealing material 17. However, the position is not particularly limited as long as it can drain the electrolyte S from a position away from the receiving chamber 14a and the receiving recess 15a. Specifically, the drain groove 31 can be provided outside the sealing material 17, opposite the exposed end surface 14c of the side wall 14b of the housing 14, or inside the sealing material 17, opposite the solid electrolyte membrane 12 covering the end surface 14c of the side wall 14b. Furthermore, if the electrolyte S can be drained, the drain portion 30 may have multiple drain ports instead of the drain groove 31. The drain groove 31 may also be formed along at least a portion of the peripheral edge 15b of the receiving recess 15a, if it can drain the permeated electrolyte S.

[0064] If the electrolyte S can be drained from the end 32b of the drain portion 30 (drain passage 32) without suction or the like, a tank or the like for recovering the drained liquid may be provided at the end 32b. However, in this embodiment, a suction pump 41 is connected to the drain portion 30 to suck the electrolyte S that has permeated the solid electrolyte membrane 12 from the drain portion 30. A recovery tank 42 for recovering the electrolyte S is provided downstream of the suction pump 41.

[0065] 2. Regarding the method of forming the metal film F,

[0066] Reference Figure 3 as well as Figure 4 The following describes the method for forming the metal film F according to the present embodiment and the function and effect of the film forming apparatus 1. Figure 3 The process flow shown here explains the film forming method.

[0067] 2-1. Regarding the substrate W placement step S1

[0068] In the method for forming the metal coating F according to the present embodiment, first, a substrate W placement step S1 is performed. In this step, the substrate W is placed on the placement table 15 (see Figure 1). Specifically, in a state where the housing 14 is arranged above the placement table 15, the substrate W is placed on the placement table 15 in a manner that the substrate W is housed in the housing recess 15a of the placement table 15. Thereby, the substrate W is arranged at a position where the solid electrolyte membrane 12 is sandwiched with the housing chamber 14a.

[0069] 2-2. Pressing process S2 of solid electrolyte membrane 12

[0070] Next, a pressing process S2 of the solid electrolyte membrane 12 is performed. In this process, as shown in FIG. 2, the solid electrolyte membrane 12 installed to the housing 14 is brought into contact with the substrate W in a state of being placed on the placement table 15, and the substrate W is pressed by the solid electrolyte membrane 12. Figure 4

[0071] Specifically, the housing 14 is moved toward the substrate W by the lifting device 16, and the solid electrolyte membrane 12 installed to the housing 14 in a manner of being opposed to the substrate W is brought into contact with the surface of the substrate W (see FIG. 2 and FIG. 3). In this contact state, the substrate W is pressed by the solid electrolyte membrane 12 under a pressure condition at which the metal coating film F is formed, by the pressing mechanism (the pressure pump 22 and the pressure adjusting valve 23). As a result, the electrolyte solution S is pressurized by the pressure pump 22, the solid electrolyte membrane 12 is conformed to the substrate W, and the electrolyte solution S in the housing 14 becomes a constant pressure set by the pressure adjusting valve 23. Thereby, the solid electrolyte membrane 12 can uniformly press the surface of the substrate W by the hydraulic pressure of the electrolyte solution S in the housing 14 after the pressure adjustment. Figure 1 Figure 4

[0072] 2-3. Film formation process S3 of metal coating film

[0073] Next, a film formation process S3 of the metal coating film is performed. In this process, as shown in FIG. 4, the metal coating film F is formed on the substrate W by applying a current between the anode 11 and the substrate W by the power supply section 13 in a state where the solid electrolyte membrane 12 is pressed. At this time, the electrolyte solution S that has passed through the solid electrolyte membrane 12 is drained from a position in the surface of the placement table 15 that is opposed to the end surface 14c of the side wall 14b of the housing 14 that forms the housing chamber 14a. More specifically, the electrolyte solution S is drained by the drain section 30. Figure 4 According to the present embodiment, by being thus configured, at a position where the solid electrolyte membrane 12 and the drain section 30 are sandwiched, there is no electrolyte solution S housed in the housing chamber 14a at the time of the film formation of the metal coating film F. That is, the electrolyte solution S is not drained from a position that is opposed to a position where the solid electrolyte membrane 12 is likely to be deformed (a position that faces the housing chamber 14a).

[0074]

[0075] ​​​​As a result, the deformation of the solid electrolyte membrane 12 due to the hydraulic pressure of the electrolyte solution S and the flow of the electrolyte solution S in a manner to block the liquid discharge portion 30 is reduced, so damage to the solid electrolyte membrane 12 is prevented, and the electrolyte solution S that has permeated the solid electrolyte membrane 12 is easily discharged through the liquid discharge portion 30.

[0076] In particular, during the formation of the metal coating film F, a liquid discharge groove 31 is provided as a part of the liquid discharge portion 30 around the substrate W housed in the housing recess 15a, so the electrolyte solution S that flows out from between the solid electrolyte membrane 12 and the substrate W is more uniformly discharged from around the substrate W. Thus, the deformation of the solid electrolyte membrane 12 away from the substrate W, as shown in FIG. 6, is suppressed. Figure 9

[0077] Further, by generating a negative pressure in the liquid discharge portion 30 using the suction pump 41, the electrolyte solution S is efficiently sucked from between the solid electrolyte membrane 12 and the substrate W and discharged to the outside of the placement stage 15 through the liquid discharge portion 30.

[0078] Thus, the electrolyte solution S that remains between the solid electrolyte membrane 12 and the substrate W is discharged, and the formation of the metal coating film F is performed uniformly on the surface of the substrate W.

[0079] [Modified Example]

[0080] Referring to Figure 5 and Figure 6 , a metal coating film F forming apparatus 1 and a metal coating film F forming method according to a modified example of the present embodiment will be described. In the present modified example, the liquid discharge through the liquid discharge portion 30 is forcibly performed by the suction pump 41 according to the voltage value between the anode 11 and the substrate W during the formation, which is different from the above-described embodiment. Hereinafter, the aspects different from the above-described embodiment will be mainly described.

[0081] As shown in Figure 5 , in the metal coating film F forming apparatus 1 of the present modified example, the suction pump 41 is connected to the liquid discharge portion 30 of the above-described embodiment. In addition, in the present modified example, the power supply portion 13 applies a current between the anode 11 and the substrate W in a manner to keep the current constant between the solid electrolyte membrane 12 and the substrate W. In order to achieve such current control, a control circuit that controls the applied voltage in a manner to keep the current measured by the ammeter 19 constant can be provided in the power supply portion 13.

[0082] By controlling the current applied between the anode 11 and the substrate W to be constant using the power supply portion 13, the formation speed of the metal coating film F can be made constant. Thus, by previously setting the time from the start of the application of the current to the end of the application, the formation of the metal coating film F of a desired thickness can be performed.

[0083] ​In this modification, the film forming apparatus 1 further includes a voltmeter 50 and a control device 60. The voltmeter 50 measures the voltage between the anode 11 and the substrate W. The voltmeter 50 is electrically connected to the control device 60 so that the measured value (voltage value) measured by the voltmeter 50 is input to the control device 60 as a signal.

[0084] The control device 60 is basically composed of a CPU and other computing devices, as well as RAM and ROM, as hardware. The computing device determines whether the voltage is above a predetermined value based on the signal from the voltmeter 50, calculates control signals for the power supply 13 and the suction pump 41, and outputs these signals. The storage device also stores, for example, a preset film formation time, the hydrogen overpotential (described later), and a preset suction time.

[0085] More specifically, the control device 60 sends a control signal to the suction pump 41 to start and stop the suction pump 41. After the suction pump 41 starts, the suction pump 41 continues to operate, and the suction by the suction pump 41 is stopped by a stop signal from the control device 60. Furthermore, the control device 60 can also control the power supply unit 13 to be energized and de-energized.

[0086] In this modification, the control device 60 starts the suction pump 41 when the voltage measured by the voltmeter 50 becomes equal to or higher than a predetermined voltage value during the formation of the metal film F, and stops the suction pump 41 after a predetermined set time has passed since the start of the suction pump 41.

[0087] Here, as the amount of electrolyte S accumulated between the solid electrolyte membrane 12 and the substrate W increases, the voltage between the anode 11 and the substrate W also increases. Furthermore, after the amount of electrolyte S accumulated reaches a predetermined level, the formed metal film begins to change color. Therefore, the "predetermined voltage" used as a reference for activating the suction pump 41 is preferably the voltage at that time or a voltage lower than that. Furthermore, the "set time," corresponding to the suction time of the suction pump 41, is preferably set to a time sufficient to draw out the electrolyte S accumulated between the solid electrolyte membrane 12 and the substrate W. This set time can be determined, for example, through experiments.

[0088] Reference Figure 6 The control flow shown explains the detailed control performed by the control device 60 together with the operation and effects.

[0089] Figure 6 1 is a control flow chart of the control device 60 . Figure 6 The control flow shown is in Figure 3 The metal film forming process S3 shown in FIG. Figure 3The metal film forming step S3 of the metal film forming method shown in the steps S1 to S3. Further, the method controlled by the control device 60 will be described below, but it can also be performed manually.

[0090] First, in step S601, the control device 60 outputs a control signal to the power supply section 13 to turn on a current between the anode 11 and the base material W in a manner to keep the current constant between the solid electrolyte film 12 and the base material W. Thereby, in a state where the base material W is pressed by the solid electrolyte film 12 for hydraulic pressure, the film forming of the metal film F is started.

[0091] Next, in step S602, the control device 60 determines whether the film forming cumulative time is less than a predetermined time set in advance. In a case where the control device 60 determines that the predetermined time or more has passed (step S602: "No"), as will be described later, it proceeds to step S603 to stop the turning on of the current and ends the film forming. On the other hand, in a case where it is determined that the film forming cumulative time is less than the predetermined time set in advance (step S602: "Yes"), since it is in the middle of the film forming, it proceeds to step S604 to determine the voltage value.

[0092] In step S604, the control device 60 determines whether the measured voltage value between the anode 11 and the base material W is the predetermined voltage value or more. The control device 60 receives the measured voltage value from the voltmeter 50 and makes the determination. For example, the control device 60 can also determine whether the increase (change) of the measured voltage value from the voltage value at the start of the film forming (initial voltage) is the predetermined value or more.

[0093] Here, in the present modification example, as an example of the predetermined value (voltage value), the hydrogen overvoltage of the metal used as the material of the metal film F is used. The control device 60 can store the hydrogen overvoltage of the metal in advance (for example, Cu: 0.58 V, Ni: 0.75 V, Zn: 0.75 V, Ag: 0.76 V, Sn: 1.08 V, and Au: 0.37 V) and read it out as appropriate at the time of determination.

[0094] In a case where the control device 60 determines that it is less than the predetermined voltage value (step S604: "No"), it returns to step S601. In this case, the electrolyte solution S that permeates through the solid electrolyte film 12 does not stay much between the solid electrolyte film 12 and the base material W, so the film forming is continued.

[0095] On the other hand, in a case where the control device 60 determines that it is the predetermined voltage value or more (step S604: "Yes"), it proceeds to step S605. In step S605, the electrolyte solution S that permeates through the solid electrolyte film 12 stays between the solid electrolyte film 12 and the base material W, so the turning on of the current is stopped by the control device 60. Thereby, the film forming of the metal film F is stopped.

[0096] Here, the time at which the initial voltage becomes the hydrogen overpotential or more is based on the hydrogen overpotential of the metal, and at this time, the current connection between the anode 11 and the base material W is stopped, so that abnormal deposition of the metal can be prevented.

[0097] Next, in step S606, the suction pump 41 is started by the control device 60, and the process proceeds to step S607. Here, in step S605, the current connection has been stopped, so even if the solid electrolyte film 12 vibrates during the suction of the suction pump 41, since the deposition of the metal film F is interrupted, deposition failure due to the vibration does not occur.

[0098] However, in a case where the solid electrolyte film 12 does not vibrate or even if it vibrates, it does not affect the deposition of the metal film F by suction, the current connection in step S605 can not be stopped, and the deposition of the metal film F can be continued. In this case, in step S606, the discharge of the electrolyte S that has permeated the solid electrolyte film 12 is started.

[0099] Next, in step S607, the control device 60 determines whether the suction time is less than a predetermined set time. The set time is not particularly limited if it is a time in which the electrolyte S that has permeated the solid electrolyte film 12 can be substantially discharged.

[0100] In a case where it is determined that the suction time is less than the predetermined set time (step S607: Yes), the process returns to step S606. In this case, the discharge is not sufficient, so the suction is continued. On the other hand, in a case where it is determined that the set time is greater than or equal to the predetermined set time (step S607: No), it can be determined that the electrolyte S has been sufficiently discharged, so the process proceeds to step S608.

[0101] In step S608, the suction pump 41 is stopped by the control device 60, and the discharge of the electrolyte S by the suction pump 41 through the discharge portion 30 is completed. After the suction pump 41 is stopped, the process returns to step S601, and the deposition is started again. In step S602, in a case where it is determined that the deposition accumulation time obtained by accumulating the current application time is not less than the predetermined time, the metal film has been deposited at the desired film thickness under the current-constant current application, so in step S603, the power supply portion 13 is stopped from connecting the current by the control device 60, and the deposition is ended. Thus, the base material W in which the metal film F is deposited at the desired film thickness can be produced. Furthermore, in a case where the start and stop of the suction pump are repeated a predetermined number of times or more, it can be determined that an abnormality has occurred in the deposition device 1, and the deposition is suspended.

[0102]

EXAMPLE

[0103] Hereinafter, the present application will be described by way of examples.

[0104] <Embodiment>

[0105] As a substrate on which a film is to be formed on a surface, a substrate (10 cm x 10 cm x Cu film thickness 500 nm) on which a Cu film was formed on a surface of a glass epoxy substrate was prepared. Next, using a film forming apparatus shown in FIG. 1, a Cu film was formed in accordance with a film forming method shown in FIG. 2, and in the film forming process of the Cu film, control by the control apparatus was performed in accordance with a control flow shown in FIG. 3. Figure 5 Figure 3 Figure 6

[0106] As an electrolyte solution, a copper sulfate aqueous solution (1 M CuSO4+ 0.2 M H2SO4) was used, as an anode, a Cu plate was used, and as a solid electrolyte film, Nafion N212 (manufactured by DuPont (GmbH)) having a film thickness of 8 μm was used. As test conditions, a temperature of 70°C, a current density of 18 A / dm2, a hydraulic pressure of 0.6 MPa, and a film forming time of 1506 seconds were used to form a Cu film having a film thickness of 1000 μm. 2

[0107] In addition, during the film forming, the voltage between the anode and the substrate was measured, and when a predetermined voltage value was determined (step S604), it was determined whether or not the increase in the measured voltage value relative to the voltage value at the start of the film forming became 0.6 V or more, which is the hydrogen overvoltage of Cu. At the time when the voltage value became 0.6 V or more, suction by a suction pump was performed for 1 minute. The appearance of the substrate after the film forming was completed was observed.

[0108] <Comparative Example>

[0109] A Cu film was formed in the same manner as in the embodiment, and the appearance after the film forming was observed. The difference from the embodiment was that no liquid discharge portion was provided, and no discharge of the electrolyte solution S remaining between the solid electrolyte film and the substrate was performed.

[0110] (Results and Investigation)

[0111] Figure 7A and Figure 7B are photographs of the appearance after the film forming of the test bodies with respect to the embodiment and the comparative example, respectively. As is apparent from Figure 7A , in the embodiment, the film forming of a homogeneous Cu film was performed. Therefore, if the electrolyte solution that has permeated the solid electrolyte film is discharged by suction by a suction pump via the liquid discharge portion as in the embodiment, it is possible to prevent the permeated electrolyte solution from remaining between the solid electrolyte film and the substrate, and to perform the film forming of a homogeneous metal film.

[0112] On the other hand, as is apparent from Figure 7B ​​​​It is understood that discoloration (so-called spots) due to abnormal deposition of metal is confirmed in the comparative example. In the comparative example, the electrolyte solution that has passed through is retained between the solid electrolyte film and the substrate, and the solid electrolyte film is deformed away from the substrate, which is considered to be the cause of the spots.

[0113] Figure 8 is a graph showing the change in voltage in the example in association with the passage of time of film formation. As shown in Figure 8 from the start of film formation, the voltage gradually increases with the passage of time, and the amount of increase in voltage becomes 0.6 V or more, which is the hydrogen overpotential of Cu, with respect to the initial voltage in the vicinity of 680 seconds of film formation time, so the attraction starts. In such a condition, in the example, the film formation of the homogeneous copper coating film is performed. According to the above, if the timing at which the attraction starts is the timing at which the amount of increase in voltage from the start of film formation reaches the hydrogen overpotential (becomes 0.6 V or more), it is considered that the film formation of the homogeneous metal coating film can be performed.

[0114] The above describes one embodiment of the present application, but the present application is not limited to the described embodiment, and various design changes can be made within the scope of the spirit of the present application recited in the claims.

Claims

1. A metal-coated film forming apparatus characterized by comprising: At least comprising: an anode; a solid electrolyte film disposed between the anode and a substrate that is a cathode; a power supply section that applies a current between the anode and the substrate; a stage on which the substrate is placed; a housing that, together with the anode, forms a housing chamber that houses an electrolyte solution, and in which the solid electrolyte film is installed in a manner that seals the housing chamber; and a voltage meter that measures the voltage between the anode and the substrate, in a state in which the substrate is pressed by the solid electrolyte film using the hydraulic pressure of the electrolyte solution that passes through the housing chamber, the current is applied, and a metal coating film is formed on the surface of the substrate from metal ions contained in the electrolyte solution, wherein a drain section is provided on the stage, the drain section drains the electrolyte solution that has passed through the solid electrolyte film from a position that opposes the end surface of the side wall of the housing, a suction pump that is connected to the drain section and that suctions the electrolyte solution from the drain section is connected to the drain section, in the formation of the metal coating film, the power supply section applies the current between the anode and the substrate in a manner that maintains the current that is applied between the anode and the substrate as constant, the film formation device comprises a control device that controls the start and stop of the suction pump, and in the formation of the metal coating film, when the voltage between the anode and the substrate, as measured by the voltage meter, becomes equal to or greater than a predetermined voltage value, the control device starts the suction pump, and after a predetermined set time has elapsed from the start of the suction pump, the control device stops the suction pump.

2. The film formation device for a metal coating film according to claim 1, wherein a housing recess that corresponds to the shape of the substrate is formed on the stage as a recess for placement, the drain section has a drain groove, and the drain groove is formed in a manner that surrounds the housing recess at intervals from the periphery of the housing recess. in a state in which the substrate is pressed by a solid electrolyte film using the hydraulic pressure of an electrolyte solution that is housed in a housing chamber, a current is applied between an anode and a substrate that is a cathode, and a metal coating film is formed on the surface of the substrate from metal ions contained in the electrolyte solution, wherein 3. A film forming method of a metal-clad film, performed by the metal-clad film forming apparatus according to claim 1 or 2, characterized by, the film formation method comprises: a step of placing the substrate on a stage; a step of bringing the solid electrolyte film into contact with the substrate that is placed on the stage and pressing the substrate by the solid electrolyte film for hydraulic pressure; and a step of applying a current between the anode and the substrate in a state in which the substrate is pressed by the solid electrolyte film, thereby forming the metal coating film on the substrate, in the step of forming the metal coating film, the electrolyte solution that has passed through the solid electrolyte film is drained from a position on the surface of the stage that opposes the end surface of the side wall of the housing that forms the housing chamber, in the step of forming the metal coating film, the electrolyte solution is drained while being suctioned by a suction pump, ​ In the film forming process, the voltage between the anode and the substrate is measured while the current is kept constant, and when the measured voltage becomes equal to or greater than a predetermined voltage value, the electrolyte is sucked using the suction pump, and after a predetermined set time elapses from the start of the sucking, the sucking using the suction pump is stopped.

4. The metal film formation method according to claim 3, wherein The placement table is formed with a housing recess corresponding to the shape of the substrate and a drain groove surrounding the housing recess at a distance from the periphery of the housing recess, In the placing process, the substrate is placed on the placement table in a manner that the substrate is housed in the housing recess, In the film forming process, the electrolyte is drained through the drain groove.

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