Wiring board manufacturing apparatus and manufacturing method

Abstract

To provide an apparatus and a method for manufacturing a wiring board capable of suppressing oxidation of a formed metal film.SOLUTION: An apparatus 20 for manufacturing a wiring board includes: an anode 21; a solid electrolyte membrane 22 disposed between the anode 21 and a substrate 10 with a seed layer; a placing table 26 facing the solid electrolyte 22, and having a substrate-placing area 27 for placing the substrate 10 with the seed layer; and a housing body 23 for housing the anode 21 and a plating solution S where an opening part 23c opened to a placing table 26 side is closed by the solid electrolyte membrane 22. The apparatus 20 for manufacturing a wiring board further incudes: a humidifier 30 for humidifying a space between the solid electrolyte 22 and the substrate 10 with the seed layer placed on the substrate-placing area 27; and a cooler 36 for cooling the substrate 10 with the seed layer placed on the substrate-placing area 27.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for manufacturing a wiring board, and more particularly to an apparatus and method for manufacturing a wiring board using solid-phase electrodeposition. [Background technology]

[0002] The solid-phase electrodeposition method is a method in which a workpiece is pressurized with a solid electrolyte film in contact with a plating solution containing metal ions, and a voltage is applied between the workpiece (anode) and the cathode, forming a metal film derived from the metal ions contained in the solid electrolyte film on the surface of the workpiece. A known method for manufacturing a wiring board using this solid-phase electrodeposition method is to form a wiring layer by depositing a metal film in a metal film formation area corresponding to a wiring pattern, as described in Patent Document 1 below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-048210 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described method for manufacturing a wiring board, after a metal film is formed, the wiring board is transported to a cleaning process to clean off any remaining plating solution on the wiring board. However, while the wiring board is being transported to the cleaning process, the remaining plating solution remains on the surface of the formed metal film, and oxygen in the air diffuses into or dissolves in the plating solution. This can cause oxidation and discoloration of the formed metal film. Furthermore, since moisture contained in the plating solution evaporates more easily at higher temperatures and lower relative humidity, in a high-temperature, low-relative-humidity environment, the formed metal film is even more likely to oxidize before being cleaned.

[0005] The present invention has been made to solve such technical problems, and aims to provide a wiring board manufacturing apparatus and manufacturing method that can suppress oxidation of the formed metal film. [Means for solving the problem]

[0006] The wiring board manufacturing apparatus according to the present invention is an apparatus for manufacturing a wiring board by forming a metal film on a surface of a substrate by a solid-phase electrodeposition method, and is characterized in that it comprises: an anode; a solid electrolyte membrane arranged between the anode and the substrate which is a cathode; a mounting table arranged opposite the solid electrolyte membrane and having a substrate mounting area on which the substrate is mounted; a container having an opening facing the mounting table which is blocked by the solid electrolyte membrane and which accommodates the anode and a plating solution; and a power supply unit which applies a voltage between the anode and the substrate; and the wiring board manufacturing apparatus further comprises at least one of a humidifier which humidifies a space between the solid electrolyte membrane and the substrate mounted in the substrate mounting area, and a cooler which cools the substrate mounted in the substrate mounting area.

[0007] The wiring substrate manufacturing apparatus according to the present invention includes at least one of a humidifier that humidifies the space between the solid electrolyte film and the substrate placed in the substrate placement area and a cooler that cools the substrate placed in the substrate placement area. Therefore, by humidifying the space between the solid electrolyte film and the substrate using the humidifier, the relative humidity of the space between the solid electrolyte film and the substrate can be increased. This suppresses evaporation of water from the plating solution remaining on the formed metal film until the substrate is cleaned after film formation, thereby suppressing oxidation of the formed metal film. Furthermore, by cooling the substrate using the cooler, the temperature of the formed metal film can be lowered. This suppresses evaporation of water from the plating solution remaining on the formed metal film until the substrate is cleaned after film formation, thereby suppressing oxidation of the formed metal film. Furthermore, using either the humidifier or the cooler effectively suppresses oxidation of the metal film. Furthermore, using both the humidifier and the cooler can be expected to enhance the effect of suppressing oxidation of the metal film.

[0008] a step of forming a metal film on the surface of a substrate by a solid-phase electrodeposition method, the step comprising: a step of bringing a solid electrolyte film into contact with the substrate placed on a mounting table facing the solid electrolyte film while sealing an opening of a housing; a step of supplying a plating solution to the housing and pressurizing the substrate with the solid electrolyte film in contact with the plating solution; a step of forming a metal film derived from metal ions contained in the solid electrolyte film on the surface of the substrate by applying a voltage while pressing the substrate; and a step of performing at least one of the following after the voltage application is completed: discharging the plating solution from the housing while cooling the substrate on which the metal film has been formed and separating the solid electrolyte film from the substrate; and a step of humidifying a space between the substrate on which the metal film has been formed and the solid electrolyte film after separating the solid electrolyte film from the substrate; and a step of removing the substrate on which the metal film has been formed from the mounting table and cleaning the substrate.

[0009] The method for manufacturing a wiring board according to the present invention includes at least one of the steps of: discharging the plating solution from the container and separating the solid electrolyte film from the substrate while cooling the substrate on which the metal film has been formed after the voltage application is terminated, and humidifying the space between the substrate on which the metal film has been formed and the solid electrolyte film after separating the solid electrolyte film from the substrate. By humidifying the space between the solid electrolyte film and the substrate and / or lowering the temperature of the metal film formed on the substrate, evaporation of the water in the plating solution remaining on the formed metal film can be suppressed until the substrate is washed after film formation, thereby suppressing oxidation of the formed metal film. [Effects of the Invention]

[0010] According to the present invention, oxidation of the formed metal film can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a cross-sectional view showing the structure of a wiring substrate manufacturing apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view showing a mounting table and a substrate with a seed layer mounted thereon. [Figure 3] 5 is a flow chart for explaining a method for manufacturing a wiring substrate according to an embodiment. FIG. [Figure 4] FIG. 2 is a cross-sectional view showing the structure of a wiring board. [Figure 5] FIG. 1 is a cross-sectional view showing a sample for evaluation. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a wiring board manufacturing apparatus and manufacturing method according to the present invention will be described with reference to the drawings. Before describing these, the structure of wiring board 1 will be briefly described.

[0013] 4, wiring board 1 includes, for example, an insulating substrate 11 and a wiring layer 2 having a predetermined wiring pattern provided on the surface of insulating substrate 11. Wiring layer 2 includes a conductive base layer 12 formed on the surface of insulating substrate 11, a metal seed layer 13 formed on the surface of base layer 12, and a metal layer 14 formed on the surface of metal seed layer 13. However, wiring layer 2 is not limited to this, and may further include, for example, a diffusion layer formed between base layer 12 and metal seed layer 13.

[0014] [Wiring board manufacturing equipment] 1, wiring substrate manufacturing apparatus 20, also referred to as a film formation apparatus, is a plating apparatus that uses solid-phase electrodeposition to form a metal layer 14 by forming a metal film in a metal film formation area corresponding to a wiring pattern. Wiring substrate manufacturing apparatus 20 includes a metal anode 21, a solid electrolyte membrane 22 disposed between the anode 21 and a seed layer-attached substrate 10 (described later) that serves as a cathode, a container 23 that accommodates the anode 21 and a plating solution S, and a power supply unit 24 that applies a voltage between the anode 21 and the base layer 12 of the seed layer-attached substrate 10. Because the base layer 12 and the metal seed layer 13 are electrically conductive, applying a voltage between the anode 21 and the base layer 12 causes a current to flow between the anode 21 and the metal seed layer 13 during film formation.

[0015] The anode 21 has a plate shape and is embedded in the top plate of the container 23 in a state facing the solid electrolyte membrane 22. The anode 21 may be a soluble anode made of the same material as the metal layer 14 (e.g., Cu), or an anode made of a material insoluble in the plating solution S (e.g., Ti).

[0016] The container 23 is made of a material insoluble in the plating solution S and is formed to have a space therein for containing the plating solution S. The container 23 has an opening 23c formed in the bottom. The opening 23c opens downward of the container 23 (i.e., toward the mounting table 26 described below) and is closed by the solid electrolyte membrane 22. In the container 23, the above-mentioned space for containing the plating solution S is formed between the anode 21 and the solid electrolyte membrane 22.

[0017] The container 23 is also provided with a supply port 23a through which the plating solution S is supplied and a discharge port 23b through which the plating solution S is discharged. The supply port 23a and the discharge port 23b are connected to a tank 31 via piping. The plating solution S is pumped from the tank 31 by a pump 32, flows into the container 23 from the supply port 23a, and is discharged from the discharge port 23b before returning to the tank 31. A pressure regulating valve 33 is provided downstream of the discharge port 23b, and the plating solution S in the container 23 can be pressurized to a predetermined pressure by the pressure regulating valve 33 and the pump 32.

[0018] The solid electrolyte membrane 22 is also called a porous membrane or a porous resin membrane, and is formed of a resin membrane having a certain degree of flexibility. When the solid electrolyte membrane 22 is brought into contact with the plating solution S, it is impregnated (contains) metal ions contained in the plating solution S. When a voltage is applied, metal derived from the metal ions is deposited on the surface of the metal seed layer 13, which serves as the cathode. The thickness of the solid electrolyte membrane 22 is, for example, about 5 μm to about 200 μm.

[0019] The solid electrolyte membrane 22 is not particularly limited as long as it can be impregnated with metal ions by contacting with the plating solution S and can precipitate metal derived from the metal ions on the surface of the cathode (metal seed layer 13) when a voltage is applied. Examples of materials for the solid electrolyte membrane 22 include fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins with cation exchange properties such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd.

[0020] The plating solution S is a solution containing the metal of the metal layer 14 in an ionic state, and examples of such metals include Cu, Ni, Ag, and Au. The plating solution S is prepared by dissolving (ionizing) these metals in an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, or pyrophosphoric acid.

[0021] Furthermore, wiring board manufacturing apparatus 20 of this embodiment includes lifting device 25 that is disposed above housing body 23 and lifts and lowers housing body 23. Lifting device 25 may be any device that can lift and lower housing body 23, and may be configured, for example, by a hydraulic or pneumatic cylinder, an electric actuator, a linear guide, a motor, or the like.

[0022] Furthermore, the wiring substrate manufacturing apparatus 20 includes a mounting table 26 on which the seed layer-equipped substrate 10 is placed. The mounting table 26 is made of a conductive material and is disposed below the container 23 so that the seed layer-equipped substrate 10 faces the solid electrolyte membrane 22. The mounting table 26 is electrically connected (conductive) to the negative electrode of the power supply unit 24. The positive electrode of the power supply unit 24 is electrically connected (conductive) to the anode 21 built into the container 23.

[0023] 1 and 2, a substrate mounting area 27 for mounting the seed layer-equipped substrate 10 is provided in the center of the mounting table 26. The substrate mounting area 27 is a rectangular parallelepiped recess into which the seed layer-equipped substrate 10 can be fitted, and has a depth such that, for example, the surface of the underlayer 12 of the seed layer-equipped substrate 10 in an arranged state and a surface 26a of the mounting table 26 are flush with each other.

[0024] Although not shown, the mounting table 26 is further provided with a conductive member that electrically connects the mounting table 26 and the seed layer-equipped substrate 10. The conductive member is formed, for example, by bending a metal plate into a Z-shaped cross section. One end of the conductive member contacts the mounting table 26, and the other end contacts the upper surface of the seed layer-equipped substrate 10 (i.e., the upper surface of the underlayer 12). This allows the mounting table 26 to be electrically connected to the underlayer 12 via the conductive member. The conductive member is detachable from the seed layer-equipped substrate 10.

[0025] The wiring board manufacturing apparatus 20 of this embodiment further includes a humidifier 30 that humidifies the space between the solid electrolyte membrane 22 and the substrate 10 with a seed layer placed in the substrate placing area 27, and a cooler 36 that cools the substrate 10 with a seed layer placed in the substrate placing area 27.

[0026] The humidifier 30 has a water vapor generation unit 35 and a plurality of (here, 32) water vapor outlets 34 connected to the water vapor generation unit 35 via piping. The water vapor generation unit 35 is disposed, for example, at a location away from the mounting table 26. The water vapor outlets 34 are provided on the mounting table 26 outside the substrate mounting area 27. As shown in FIG. 2 , the 32 water vapor outlets 34 are arranged in groups of eight along the four peripheries of the substrate mounting area 27 so as to surround the substrate mounting area 27.

[0027] 1, each water vapor outlet 34 is embedded in the mounting table 26 so as not to protrude from the surface 26a of the mounting table 26, so as not to affect the contact between the solid electrolyte membrane 22 and the seed layer-equipped substrate 10, and is arranged straight so that water vapor from the water vapor outlet 34 flows upward (i.e., toward the solid electrolyte membrane 22). Note that each water vapor outlet 34 may be arranged at an angle toward the center of the substrate mounting area 27, so that water vapor from the water vapor outlet 34 gathers at the center of the seed layer-equipped substrate 10.

[0028] The cooler 36 is built into the mounting table 26 below the substrate mounting area 27. In order to cool the seed layer-equipped substrate 10 more efficiently, the cooler 36 is disposed directly below the substrate mounting area 27 so that its surface forms the bottom surface of the substrate mounting area 27 (see FIG. 1), and is formed larger than the area of ​​the seed layer-equipped substrate 10 mounted on the substrate mounting area 27 (see FIG. 2). The cooler 36 may be one equipped with a heat sink or a cooling fan.

[0029] The wiring substrate manufacturing apparatus 20 configured as described above includes a humidifier 30 that humidifies the space between the solid electrolyte film 22 and the seed layer-equipped substrate 10 placed in the substrate-mounting area 27, and a cooler 36 that cools the seed layer-equipped substrate 10 placed in the substrate-mounting area 27. Therefore, by humidifying the space between the solid electrolyte film 22 and the seed layer-equipped substrate 10 placed in the substrate-mounting area 27 using the humidifier 30, the relative humidity of the space between the solid electrolyte film 22 and the seed layer-equipped substrate 10 can be increased. This suppresses evaporation of water from the plating solution remaining on the formed metal coating until the seed layer-equipped substrate 10 is cleaned after film formation, thereby suppressing oxidation of the formed metal coating. In addition, cooling the seed layer-equipped substrate 10 with the cooler 36 reduces the temperature of the formed metal coating. This suppresses evaporation of water from the plating solution remaining on the metal coating until the seed layer-equipped substrate 10 is cleaned after film formation, thereby suppressing oxidation of the formed metal coating.

[0030] In this embodiment, an example has been described in which both the humidifier 30 and the cooler 36 are provided, but even when using only one of the humidifier 30 and the cooler 36, the effect of inhibiting oxidation of the formed metal coating can be obtained, so it is also possible to provide only one of the humidifier 30 and the cooler 36.

[0031] [Method of manufacturing wiring board] The method for manufacturing a wiring substrate according to this embodiment will be described below. As shown in Figure 3, the method for manufacturing a wiring substrate according to this embodiment includes a preparation step S1, a pressure step S2, a film formation step S3, a humidification and cooling step S4, a cleaning step S5, and a wiring layer formation step S6.

[0032] First, in the preparation step S1, a conductive underlayer 12 and a metal seed layer 13 corresponding to a predetermined wiring pattern are sequentially formed on the surface of an insulating substrate 11 to prepare a base material 10 with a seed layer. A well-known technique (for example, the technique disclosed in Patent Document 1) can be used as a method for sequentially forming the underlayer 12 and the metal seed layer 13 on the surface of the insulating substrate 11. A detailed description thereof will be omitted here.

[0033] The insulating substrate 11 is not particularly limited as long as it has insulating properties, but it is preferable to use, for example, a substrate made of glass epoxy resin, a substrate made of baked glass epoxy resin, a flexible film-like substrate such as polyimide resin, or a substrate made of glass.

[0034] The underlayer 12 is a layer for passing a current through the metal seed layer 13 when the metal layer 14 is formed. As shown in FIG. 1 , in the seed layer-attached substrate 10, the underlayer 12 is formed over the entire surface of the insulating substrate 11. The underlayer 12 is a layer containing an oxide. The oxide may be an oxide derived from the metal constituting the underlayer 12, or may be an oxide attached to the main body of the underlayer 12. This oxide prevents the metal derived from the metal layer 14 from depositing on the surface of the exposed portion 12a of the underlayer 12 (in other words, the portion of the surface of the underlayer 12 on which the metal seed layer 13 is not formed) even when the solid electrolyte membrane 22 comes into contact with the surface, in other words, the portion of the surface of the underlayer 12 on which the metal seed layer 13 is not formed) in the subsequent film-forming step S3. This allows the metal to be selectively deposited on the metal seed layer 13.

[0035] The metal seed layer 13 is formed to correspond to the wiring pattern of the wiring board 1, and is formed, for example, to have a plurality of independent wiring patterns. In the seed layer-attached substrate 10, the independent wiring patterns are electrically connected to each other via the underlayer 12. Therefore, in the film-forming step S3 described below, it is not necessary to form a lead wire for applying a voltage to each wiring pattern, and the metal layer 14 can be formed simultaneously on each wiring pattern. The metal seed layer 13 is, for example, at least one selected from the group consisting of silver, copper, gold, palladium, and platinum.

[0036] In the seed layer-equipped substrate 10 having such a structure, the surface of the metal seed layer 13 having multiple wiring patterns is the area where a metal film is formed in the subsequent film-forming step S3, i.e., the metal film formation area of ​​the seed layer-equipped substrate 10. The remaining portions of the seed layer-equipped substrate 10 other than the surface of the metal seed layer 13 (for example, the surface of the exposed portion 12a of the underlayer 12) are the non-metal film formation area of ​​the seed layer-equipped substrate 10.

[0037] In the pressurizing step S2 following the preparation step S1, the solid electrolyte membrane 22 in contact with the plating solution S is pressed against the seed layer-equipped substrate 10. Specifically, first, the seed layer-equipped substrate 10 is placed on the substrate placing area 27 of the placing table 26, and the placing table 26 and the upper surface of the underlayer 12 of the seed layer-equipped substrate 10 are electrically connected by the conductive member described above. Next, the solid electrolyte membrane 22 is attached to the lower end of the accommodation body 23 so that the solid electrolyte membrane 22 closes the opening 23c formed in the bottom of the accommodation body 23. Next, with the opening 23c of the accommodation body 23 closed by the solid electrolyte membrane 22, the accommodation body 23 is lowered by the lifting device 25, and the solid electrolyte membrane 22 comes into contact with the surface of the metal seed layer 13 of the seed layer-equipped substrate 10 and the surface of the exposed portion 12a of the underlayer 12.

[0038] Next, the pump 32 is driven to supply the plating solution S stored in the tank 31 to the container 23. As a result, the plating solution S stored in the tank 31 flows into the container 23 from the supply port 23a. Then, the liquid pressure of the plating solution S can uniformly pressurize the surface of the metal seed layer 13 of the solid electrolyte membrane 22 and the surface of the exposed portion 12a of the base layer 12. The applied pressure can be adjusted using, for example, a pressure regulating valve 33.

[0039] In the film-forming step S3 following the pressurizing step S2, a voltage is applied to form a metal film on the metal film formation area of ​​the seed layer-formed substrate 10 while the seed layer-formed substrate 10 is being pressurized by the solid electrolyte membrane 22. Specifically, a voltage is applied between the anode 21 and the underlayer 12 using the power supply unit 24, and metal ions contained in the solid electrolyte membrane 22 are reduced, resulting in the deposition of metal derived from the metal ions on the surface of the metal seed layer 13 (i.e., the metal film formation area). Furthermore, as a result of the application of voltage, the metal ions of the plating solution S in the container 23 continue to be reduced at the cathode, forming a metal film on the surface of the metal seed layer 13. The formed metal film becomes the metal layer 14 described above (see FIG. 1 ). At this time, it is preferable to heat the seed layer-formed substrate 10 with a heater (not shown) to increase the deposition rate of the metal film.

[0040] Here, if the surface of the exposed portion 12a of the base layer 12 (i.e., the non-metallic film-formed area) contains an oxide such as a natural oxide film or an oxide film formed by surface treatment, as described above, the insulating properties of the surface of the exposed portion 12a are enhanced. Therefore, when the solid electrolyte film 22 is in close contact with the surface of the metal seed layer 13 and the surface of the exposed portion 12a of the base layer 12, current flows only on the surface of the metal seed layer 13.

[0041] As a result, metal ions (e.g., Cu ions) contained in the solid electrolyte film 22 are reduced on the surface of the metal seed layer 13, and metal (e.g., Cu) is precipitated. As a result, metal precipitation on the surface of the exposed portion 12a of the base layer 12 is prevented, and a metal layer 14 is selectively formed on the surface of the metal seed layer 13. Note that the solid electrolyte film 22 may be in contact with only the metal seed layer 13. In this case, metal is not precipitated on the surface of the exposed portion 12a of the base layer 12, and the metal layer 14 is formed only on the surface of the metal seed layer 13.

[0042] In the humidifying and cooling step S4 following the film-forming step S3, the substrate 10 with the seed layer formed thereon is cooled while humidifying the space between the substrate 10 with the seed layer and the solid electrolyte membrane 22. Specifically, when the metal layer 14 is formed to a predetermined thickness, the application of voltage between the anode 21 and the underlayer 12 is terminated, the heater for heating the substrate 10 with the seed layer is turned off, and the cooler 36 is immediately operated to cool the substrate 10 with the seed layer formed thereon.

[0043] Next, for example, compressed air is supplied into the container 23, and the plating solution S inside the container 23 is discharged from the discharge port 23b using the compressed air. The discharged plating solution S is returned to the tank 31. Next, the container 23 is raised to a predetermined height by the lifting device 25, and the solid electrolyte membrane 22 is separated from the seed layer-equipped substrate 10 on which the metal coating (i.e., the metal layer 14) has been formed. This creates a space between the solid electrolyte membrane 22 and the seed layer-equipped substrate 10.

[0044] Next, the humidifier 30 is activated, causing water vapor from the water vapor generating unit 35 to pass through the piping and the water vapor outlet 34 and fill the space between the solid electrolyte membrane 22 and the seed layer-formed substrate 10.

[0045] In the cleaning step S5 following the humidifying and cooling step S4, the seed layer-equipped substrate 10 on which the metal coating film is formed is removed from the mounting table 26, transported to a water washing tank, and washed in the water washing tank. After washing, the seed layer-equipped substrate 10 on which the metal layer 14 is formed is dried.

[0046] In the wiring layer forming step S6 following the cleaning step S5, the exposed portion 12a of the base layer 12 exposed from the metal seed layer 13 is removed to form the wiring layer 2 on the surface of the insulating substrate 11. The method for removing the base layer 12 is not particularly limited, but may be, for example, plasma etching, sputtering, chemical etching, or the like.

[0047] By removing exposed portion 12a of base layer 12, as shown in Fig. 4, wiring layer 2 including, in this order, the portion of base layer 12 other than exposed portion 12a, metal seed layer 13, and metal layer 14 is formed on the surface of insulating substrate 11. In this way, wiring board 1 is manufactured.

[0048] According to the wiring board manufacturing method of this embodiment, in the humidifying and cooling step S4, after the voltage application is completed, the seed layer-equipped substrate 10 on which the metal film is formed is cooled by the cooler 36, while the space between the seed layer-equipped substrate 10 on which the metal film is formed and the solid electrolyte film 22 is humidified by the humidifier 30. This makes it possible to lower the temperature of the formed metal film while increasing the relative humidity of the space between the seed layer-equipped substrate 10 and the solid electrolyte film 22. As a result, evaporation of water in the plating solution remaining on the metal film can be suppressed until the seed layer-equipped substrate 10 is washed after film formation, thereby suppressing oxidation of the formed metal film.

[0049] In this embodiment, the substrate 10 with the seed layer on which the metal coating is formed is cooled while the space between the substrate 10 with the seed layer and the solid electrolyte membrane 22 is humidified. However, the effect of inhibiting oxidation of the formed metal coating can be obtained by either cooling the substrate 10 with the seed layer or humidifying the space between the substrate 10 with the seed layer and the solid electrolyte membrane 22.

[0050] [Evaluation Test 1] In evaluation test 1, first, multiple Cu substrates with a thickness of 3 mm were prepared and pre-treated under the same conditions. The metal film area on each Cu substrate was 2 cm × 1 cm. 2 Next, the Cu substrate was subjected to cathodic electrolytic degreasing using an alkaline electrolytic cleaning solution (manufactured by JCU Corporation, product name IC-200RM) at 55°C for 1 minute, and then washed with pure water for 1 minute. Subsequently, the Cu substrate was further immersed in dilute sulfuric acid (concentration 10%) at room temperature for 1 minute, and then washed with pure water for 1 minute.

[0051] Next, a 10 μm thick metal film was formed on the Cu substrate by solid-phase electrodeposition. An oxygen-free copper plate was used as the anode, and a solution containing 1 mol / L copper sulfate and 0.2 mol / L sulfuric acid was used as the plating solution. The distance between the anode and cathode (i.e., the Cu substrate) was 2 mm, the current was 100 mA, and the pressure was 1 kN. The film formation temperatures (i.e., the temperature of the plating solution) were 25°C, 42°C, and 70°C.

[0052] Next, after separating the solid electrolyte film from the Cu substrate, a sample in which water vapor was sprayed onto the surface of the Cu substrate after film formation (with vapor spraying) and a sample in which water vapor was not sprayed (without vapor spraying) were prepared. The prepared samples were then removed at any time, washed with pure water, and dried with an air blower. The presence or absence of discoloration (in other words, the presence or absence of oxidation) was then visually confirmed for each of the two types of samples, and the time until discoloration occurred was measured. The shortest time until discoloration occurred for each sample was determined as the time until discoloration occurred.

[0053] [Table 1]

[0054] Table 1 shows the measurement results of the time until discoloration occurred for each sample. The "substrate temperature" listed in Table 1 was set to the same as the film formation temperature. As shown in Table 1, the lower the temperature of the plating solution, the more difficult it is for the water in the plating solution to evaporate, so it was found that the time until discoloration occurred was longer. It was also found that spraying water vapor extended the time until discoloration occurred.

[0055] [Evaluation Test 2] Furthermore, based on the method described in "Drying Technology in Surface Treatment" (Masaaki Nakamura, Surface Technology, Vol. 66, No. 7, 2015), the inventors of the present application prepared a sample by forming a 2 μm water film on the surface of a substrate (3 mm thick) made of pure copper plate as shown in FIG. 5, and left the prepared sample in the air. They calculated the time until the water film evaporated (dried) under the conditions shown in Table 2, and evaluated the effects of temperature and relative humidity.

[0056] In Table 2, the film formation temperature indicates the temperature at which a water film is formed on the surface of the substrate. The film formation temperatures were 25°C, 42°C, and 70°C. The substrate cooling temperature was 25°C. Note that "none" for the substrate cooling temperature means that the substrate was not cooled.

[0057] In addition, since the atmospheric temperature and the initial temperature of the water film are slightly lower than the film formation temperature, calculations were made using 25°C when the film formation temperature was 25°C, 32°C when the film formation temperature was 42°C, and 50°C when the film formation temperature was 70°C. Adjustments were made to correspond to the times listed in Table 2. In addition, calculations were made with the atmospheric humidity varied between 30% and 80% relative humidity.

[0058] [Table 2]

[0059] As shown in Table 2, it was found that, for all film formation temperatures, increasing the relative humidity lengthened the time until water vapor evaporated. It was also found that, at the same relative humidity, cooling the substrate lengthened the time until water vapor evaporated. Furthermore, it was found that, at high relative humidity, cooling the substrate can further lengthen the time until water vapor evaporated. This demonstrates that, as described above, either cooling the substrate with the seed layer or humidifying the space between the substrate with the seed layer and the solid electrolyte membrane can suppress the evaporation of water in the plating solution, thereby achieving an effect of inhibiting oxidation of the metal film. It was also shown that performing both cooling and humidification can improve the effect of inhibiting oxidation of the metal film.

[0060] 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 set forth in the claims. [Explanation of symbols]

[0061] 1: wiring substrate, 10: base material with seed layer, 11: insulating substrate, 12: underlayer, 12a: exposed portion, 13: metal seed layer, 14: metal layer, 20: wiring substrate manufacturing apparatus, 21: anode, 22: solid electrolyte membrane, 23: container, 23a: supply port, 23b: discharge port, 23c: opening, 24: power supply unit, 25: lifting device, 26: mounting table, 26a: surface, 27: base material mounting area, 30: humidifier, 31: tank, 32: pump, 33: pressure regulating valve, 34: water vapor outlet, 35: water vapor generating unit, 36: cooler

Claims

1. A wiring board manufacturing apparatus for manufacturing a wiring board by forming a metal film on a surface of a substrate by a solid phase electrodeposition method, an anode; a solid electrolyte membrane disposed between the anode and the substrate serving as a cathode; a mounting table disposed opposite the solid electrolyte membrane and having a substrate mounting area on which the substrate is mounted; a container having an opening on the mounting table side and closed by the solid electrolyte membrane, the container containing the anode and the plating solution; a power supply unit that applies a voltage between the anode and the substrate; Equipped with The wiring substrate manufacturing apparatus further comprises at least one of a humidifier that humidifies a space between the solid electrolyte membrane and the substrate placed in the substrate placing area, and a cooler that cools the substrate placed in the substrate placing area.

2. A method for manufacturing a wiring board by forming a metal film on a surface of a substrate by a solid phase electrodeposition method, a step of bringing the solid electrolyte membrane into contact with the substrate placed on a mounting table facing the solid electrolyte membrane while the opening of the container is closed with the solid electrolyte membrane, supplying a plating solution to the container, and applying pressure to the substrate with the solid electrolyte membrane in contact with the plating solution; forming a metal coating on the surface of the substrate by applying a voltage while the substrate is pressurized, the metal coating being derived from metal ions contained in the solid electrolyte membrane; After the voltage application is completed, the plating solution is discharged from the container while cooling the substrate on which the metal film is formed, and the solid electrolyte film is separated from the substrate, and after the solid electrolyte film is separated from the substrate, the space between the substrate on which the metal film is formed and the solid electrolyte film is humidified; removing the substrate on which the metal coating film has been formed from the mounting table and cleaning it; A method for manufacturing a wiring substrate, comprising:

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