JP2024103838A - METHOD FOR FORMING METAL FILM AND APPARATUS THEREOF - Google Patents

Abstract

[Problem] To provide a method for forming a metal film, which can stably form a metal film having a predetermined pattern in a shorter time by using a screen mask. [Solution] After a second plating solution L2 containing metal ions is supplied to the surface of a screen mask 62 on the electrolyte membrane 13 side, the second plating solution L2 is filled into a through portion 68 of the screen mask 62 while pressing the substrate B with the screen mask 62 through the electrolyte membrane 13. By maintaining the pressed state and applying a voltage between the anode 11 in the container 15 and the substrate B, the metal ions contained in the first plating solution L1 are passed through the electrolyte membrane 13, and a metal film F is formed on the substrate B in a predetermined pattern P. [Selected Figure] Figure 3

Description

The present invention relates to a deposition method and deposition device for depositing a metal film of a predetermined pattern on the surface of a substrate.

Conventionally, metal is deposited on the surface of a substrate by electrolytic plating to form a metal film (see, for example, Patent Document 1). The film forming apparatus includes a container that contains a plating solution. The container has an opening that is sealed with an electrolyte membrane. The film forming apparatus further includes a pressing mechanism that presses the electrolyte membrane against the substrate by the hydraulic pressure of the plating solution.

Here, if a metallic underlayer of a predetermined pattern is formed on the surface of the substrate, a voltage is applied between the anode and the substrate while the substrate is pressed by the liquid pressure of the electrolyte membrane. This allows a metal coating of a predetermined pattern to be formed on the underlayer. However, if no underlayer of a predetermined pattern is formed on the substrate, it is also conceivable to use a masking material such as that shown in Patent Document 2.

JP 2022-001658 A JP 2016-108586 A

Here, when a metal film is formed using a screen mask as a masking material, the screen mask is sandwiched between the substrate and the electrolyte membrane. In this state, in order to ensure close contact between the substrate and the screen mask, the screen mask is pressed by the electrolyte membrane acting on the hydraulic pressure of the plating solution while the metal film is formed on the surface of the substrate. However, if a conductive fluid or the like is not filled in the through-holes of the specified pattern formed in the screen mask during film formation, there is a risk of poor film formation.

Here, if the hydraulic pressure of the plating solution is used to press the screen mask through the electrolyte membrane, it is possible to make the plating solution seep out from the electrolyte membrane and fill the through-holes with this seeped plating solution. However, this type of filling takes a long time, and as a result, it takes a long time to form the metal film.

The present invention has been made in consideration of these points, and aims to provide a metal film deposition method and deposition apparatus that can stably deposit a metal film having a predetermined pattern in a shorter time using a screen mask.

In view of the above problem, the method for forming a metal film according to the present invention is a method for forming a metal film having a predetermined pattern on a substrate by electrolytic plating in a state where a screen mask is sandwiched between an electrolyte membrane and a substrate. The method includes a pressing step in which the substrate is covered with the screen mask having a perforation portion of a predetermined pattern, and the substrate is pressed by the screen mask through the electrolyte membrane by the hydraulic pressure of a first plating solution sealed in a container by the electrolyte membrane, and a film forming step in which a voltage is applied between an anode in the container and the substrate, thereby passing metal ions contained in the first plating solution through the electrolyte membrane, and forming a metal film derived from the metal ions on the substrate in the predetermined pattern. In the pressing step, a second plating solution containing the metal ions is supplied to the surface of the screen mask on the electrolyte membrane side, and the second plating solution is filled in the perforation portion while pressing the substrate with the screen mask through the electrolyte membrane.

In a preferred embodiment, the screen mask is attached to the container at a position facing the electrolyte membrane such that a gap is formed between the screen mask and the electrolyte membrane, and in the pressing step, the second plating solution is supplied to the gap while the substrate is covered with the screen mask.

In a further preferred embodiment, the screen mask comprises a resin mesh portion having openings formed in a lattice pattern, and a mask portion fixed to the mesh portion on the substrate side and having the through-holes formed therein, and after the film-forming step, the container is separated from the substrate while retaining the second plating solution supplied to the gap.

The metal film forming apparatus according to the present invention is a film forming apparatus that forms a metal film having a predetermined pattern on a substrate by electrolytic plating with a screen mask sandwiched between an electrolyte membrane and a substrate. The film forming apparatus includes a container that contains a first plating solution containing metal ions for film formation and seals the first plating solution with the electrolyte membrane, a screen mask that has a perforation portion of the predetermined pattern and covers the substrate, a pressing mechanism that applies the liquid pressure of the first plating solution in the container to the electrolyte membrane and presses the substrate with the screen mask through the electrolyte membrane, an anode that is contained in the container and arranged at a distance from the electrolyte membrane, a power source for film formation that applies a voltage between the anode and the container, and a supply mechanism that supplies a second plating solution containing the metal ions to the surface of the screen mask on the electrolyte membrane side before pressing by the pressing mechanism.

In a preferred embodiment, the screen mask is attached to the container at a position facing the electrolyte membrane such that a gap is formed between the screen mask and the electrolyte membrane, and the supply mechanism supplies the second plating solution to the gap.

The film formation method and film formation apparatus of the present invention allow a metal film having a predetermined pattern to be formed stably in a shorter time using a screen mask.

FIG. 1A is a schematic cross-sectional view showing an example of a metal film forming apparatus according to an embodiment of the present invention, FIG. 1B is a schematic perspective view of a screen mask, and FIG. 1C is a partially enlarged cross-sectional view taken along line A-A in FIG. FIG. 2 is a flow diagram illustrating an example of a method for forming a metal coating according to an embodiment of the present invention. 3A is a schematic cross-sectional view for explaining the pressing step shown in FIG. 2, and FIG. 3B is a schematic cross-sectional view for explaining the film forming step shown in FIG. 2. FIG. 1A is a schematic cross-sectional view illustrating a film forming apparatus according to a modified example, and FIG. 1B is a schematic cross-sectional view illustrating a film forming process.

First, a description will be given of a film forming apparatus 1 used in a method for forming a metal film according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of a film forming apparatus for forming a metal film according to an embodiment of the present invention.

As shown in FIG. 1, the film forming apparatus 1 is a film forming apparatus that forms a metal film F of a predetermined pattern P on the substrate B by electrolytic plating with a mask structure 60 sandwiched between the electrolyte membrane 13 and the substrate B. Specifically, the film forming apparatus 1 includes an anode 11, an electrolyte membrane 13, and a power source 14 that applies a voltage between the anode 11 and the substrate B.

The film forming apparatus 1 includes a container 15 that contains an anode 11 and a plating solution L (first plating solution L1), a mounting table 40 on which a substrate B is placed, and a mask structure 60 that is integrally attached to the container 15. Of the mask structure 60, a screen mask 62 (described later) is attached to the container 15 at a position facing the electrolyte membrane 13.

The film forming apparatus 1 is equipped with a linear actuator 70 that raises and lowers the container 15. The linear actuator 70 is a moving device that moves the container 15 so that the screen mask 62 moves toward and away from the substrate B. The linear actuator 70 has a rod 72 that moves linearly with respect to the main body 71, and the container 15 is fixed to the tip of the rod 72. In this embodiment, for convenience of explanation, the electrolyte membrane 13 is disposed below the anode 11, and the mask structure 60 and substrate B are disposed further below that. However, as long as a metal film F can be formed on the surface of the substrate B, the positional relationship between the electrolyte membrane 13 and the substrate B is not particularly limited.

The substrate B functions as a cathode. The substrate B is a plate-shaped substrate. In this embodiment, the substrate B is a rectangular substrate. Of the surfaces of the substrate B, the opposing surface Ba facing the electrolyte membrane 13 (screen mask 62) is a film formation surface that functions as a cathode. The material of the substrate B is not particularly limited as long as it functions as a cathode (i.e., a surface having electrical conductivity). The substrate B may be made of a metal material such as aluminum or copper. When forming a wiring pattern from the metal coating F, the substrate B is a substrate in which a base layer such as copper is formed on the surface of an insulating substrate such as resin. In this case, after the metal coating F is formed, the base layer other than the portion on which the metal coating F is formed is removed by etching or the like. This allows a wiring pattern to be formed from the metal coating F on the surface of the insulating substrate.

The anode 11 is, for example, a non-porous anode made of the same metal as the metal of the metal coating. The anode 11 has a block or plate shape. The anode 11 is contained in a container 15 and is arranged so as to be spaced apart from the electrolyte membrane 13. The anode 11 may be porous, mesh, or a cage containing multiple balls. Examples of materials for the anode 11 include copper. The anode 11 dissolves when a voltage is applied from the power source 14. However, when the film is formed using only the metal ions of the plating solution L, the anode 11 is an anode that is insoluble in the plating solution L.

The anode 11 is electrically connected to the positive electrode of the power source 14. The negative electrode of the power source 14 is electrically connected to the substrate B via the mounting table 40, and is further connected to the mesh portion 64 of the screen mask 62 described later.

The plating solution L is a solution containing the metal of the metal film to be formed in an ion state. Examples of the metal include copper, nickel, gold, and silver. The plating solution L is a solution in which these metals are dissolved (ionized) with an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, sulfamic acid, or pyrophosphoric acid. Examples of the solvent of the solution include water and alcohol. For example, when the metal is copper, the plating solution L may be an aqueous solution containing copper sulfate or copper pyrophosphate. In the following specification, the plating solution L contained in the container 15 may be referred to as the first plating solution L1, and the plating solution L supplied to the surface of the screen mask 62 may be referred to as the second plating solution L2.

The electrolyte membrane 13 is a membrane that can be impregnated (contained) with metal ions together with the plating solution L by contacting the electrolyte membrane 13 with the plating solution L. The electrolyte membrane 13 is a flexible membrane. The material of the electrolyte membrane 13 is not particularly limited as long as the metal ions of the plating solution L can migrate to the substrate B side when a voltage is applied from the power source 14. Examples of the material of the electrolyte membrane 13 include resins with ion exchange function such as fluororesins such as Nafion (registered trademark) manufactured by DuPont. The thickness of the electrolyte membrane 13 is preferably in the range of 5 μm to 200 μm. More preferably, the thickness is in the range of 20 μm to 60 μm.

The container 15 is made of a material that is insoluble in the plating solution L. The container 15 has a container space 15a that contains the plating solution L (first plating solution L1). The anode 11 is disposed in the container space 15a of the container 15. An opening 15d is formed on the side of the container space 15a facing the substrate B. The opening 15d of the container 15 is covered with the electrolyte membrane 13.

As shown in FIG. 1(a) and FIG. 3(a), the linear actuator (moving device) 70 moves the housing 15 up and down (moves it) by linearly moving the rod 72 so that the electrolyte membrane 13 and the mask structure 60 can be brought into contact with and separated from each other. In this embodiment, the mounting table 40 is fixed, and the housing 15 is raised and lowered by the linear actuator 70. The linear actuator 70 is an electric actuator that converts the rotational motion of a motor into linear motion by a ball screw or the like (not shown). However, instead of the electric actuator, a hydraulic or pneumatic actuator may be used.

The container 15 has a supply port 15b that supplies the plating solution L (first plating solution L1) to the container space 15a. The container 15 has a discharge port 15c that discharges the plating solution L (first plating solution L1) from the container space 15a. The supply port 15b and the discharge port 15c are holes that communicate with the container space 15a. The supply port 15b and the discharge port 15c are formed on either side of the container space 15a. The supply port 15b is connected to a supply pipe 51. The discharge port 15c is fluidly connected to a discharge pipe 52.

The film forming apparatus 1 further includes a tank 90, a supply pipe 51, a discharge pipe 52, and a pump 83. As shown in FIG. 1, the tank 90 contains plating solution L. The supply pipe 51 connects the tank 90 to the container 15. The supply pipe 51 is provided with a pump 83. The pump 83 supplies plating solution L from the tank 90 to the container 15. The discharge pipe 52 connects the tank 90 to the container 15. The discharge pipe 52 is provided with a pressure adjustment valve 55. The pressure adjustment valve 55 adjusts the pressure (liquid pressure) of the plating solution L (first plating solution L1) in the container space 15a to a predetermined pressure.

In this embodiment, by driving the pump 83, the plating solution L is sucked from the tank 90 into the supply pipe 51. The sucked plating solution L is pumped from the supply port 15b to the storage space 15a. The plating solution L (first plating solution L1) in the storage space 15a is returned to the tank 90 via the discharge port 15c. A circulation path 50 for circulating the plating solution L can be formed between the tank 90 and the storage body 15.

Furthermore, by continuing to drive the pump 83, the liquid pressure of the plating solution L (first plating solution L1) in the storage space 15a can be maintained at a predetermined pressure by the pressure adjustment valve 55. The pump 83 applies the liquid pressure of the plating solution L to the electrolyte membrane 13, and presses the substrate B with the screen mask 62 of the mask structure 60 through the electrolyte membrane 13. In this embodiment, the pump 83 and the pressure adjustment valve 55 correspond to the "pressing mechanism" of the present invention.

The mask structure 60 is attached to the housing 15 at a position facing the electrolyte membrane 13 on the side facing the mounting table 40. Specifically, the mask structure 60 includes a frame 61 and a screen mask 62. The screen mask 62 has a through portion 68 formed according to a predetermined pattern P of the metal coating F. The screen mask 62 includes a mesh portion 64 and a mask portion 65. The screen mask 62 is a mask having a flexibility of about 50 μm to 400 μm. The screen mask 62 is attached to the housing 15 at a position facing the electrolyte membrane 13 so that a gap S is formed between the screen mask 62 and the electrolyte membrane 13. The screen mask 62 is supported by the frame 61 at a surface of the frame 61 that faces the substrate B (facing surface).

The mesh portion 64 is fixed to the frame body 61. The mesh portion 64 is stretched with a predetermined tension so as to cover the opening of the frame body 61. The mesh portion 64 has a plurality of openings 64c formed in a lattice shape. The mesh portion 64 is woven in a mesh shape so that the oriented wires 64a, 64b cross each other. The wires 64a are arranged at intervals, and the wires 64b, 64b that cross these are arranged at intervals. As a result, the mesh portion 64 has a plurality of openings 64c formed in a lattice shape. The material of the wires 64a, 64b is not particularly limited as long as it is a material that is corrosion-resistant to the plating solution L and conductive. For example, a resin material such as polyester resin can be used as the material of the wires 64a, 64b.

The mask portion 65 is fixed to the mesh portion 64 on the surface (substrate B side) facing the substrate B of both sides of the mesh portion 64. The mask portion 65 has a through portion 68 formed therein according to a predetermined pattern P. The mask portion 65 is a portion that adheres to the substrate B during film formation due to pressure from the electrolyte membrane 13. The material of the mask portion 65 is not particularly limited as long as it can adhere to the substrate B. It is preferable that the mask portion 65 undergoes compressive elastic deformation due to pressure from the electrolyte membrane 13. For example, the material of the mask portion 65 may be a resin material such as acrylic resin, vinyl acetate resin, polyvinyl resin, polyimide resin, or polyester resin, or a rubber material such as silicone rubber. The screen mask 62 having the predetermined pattern P can be manufactured by a general silk screen manufacturing technique using an emulsion. Therefore, a detailed description of the manufacturing method of the screen mask 62 is omitted.

In this embodiment, the mask structure 60 and the container 15 are separate bodies, but for example, the frame 61 may fit into the opening 15d of the container 15, and the mask structure 60 and the container 15 may be integrated. This not only allows the screen mask 62 to be attached to the container 15, but also allows the screen mask 62 to support the deflection of the electrolyte membrane 13 caused by the weight of the plating solution L contained in the container 15.

The screen mask 62 is fixed to the frame 61. In this embodiment, the screen mask 62 has a rectangular outer shape. Therefore, the frame 61 has a rectangular frame-like shape. The material of the frame 61 is not particularly limited as long as it can maintain the shape of the mask structure 60. For example, the material of the frame 61 can be a metal material such as stainless steel, or a resin material such as polyester. As shown in FIG. 1B, the frame 61 has a supply flow path 15e for supplying the second plating liquid L2 and a discharge flow path 15f for discharging the second plating liquid L2 in the space inside the frame 61. The supply flow path 15e and the discharge flow path 15f are also formed in the container 15 at the corresponding positions when the mask structure 60 is attached to the container 15. Although the supply flow path 15e and the discharge flow path 15f are holes, they may be grooves as long as they can flow the second plating liquid L2, and these flow paths may be formed by separate piping.

In this embodiment, a supply mechanism 16 is provided that supplies the second plating liquid L2 to the surface of the screen mask 62 that forms the gap S from the electrolyte membrane 13 side before pressing by the pump 83 (pressing mechanism). Specifically, the supply mechanism 16 supplies the second plating liquid L2 to the gap S formed between the electrolyte membrane 13 and the screen mask 62.

In this embodiment, the supply mechanism 16 is provided with a three-way valve 57 for selectively supplying the plating solution L (second plating solution L2) in the tank 90 to the supply flow path 15e. The three-way valve 57 is disposed in the supply pipe 51. By switching the three-way valve 57, it is possible to select the supply of the first plating solution L1 to the container 15 or the supply of the second plating solution L2 to the surface of the screen mask 62. Furthermore, the supply mechanism 16 is connected to a suction pump 82 that sucks the second plating solution L2 supplied to the surface of the screen mask 62 on the electrolyte membrane 13 side together with air through the discharge flow path 15f. An opening/closing valve 58 is provided between the suction pump 82 and the discharge flow path 15f, and a drain tank 59 is connected downstream of the opening/closing valve 58, which branches off from the suction pump 82.

Here, in this embodiment, the supply mechanism 16 supplies the second plating liquid L2 to the gap S formed between the electrolyte membrane 13 and the screen mask 62 with the linear actuator 70 while the screen mask 62 is in contact with the surface of the substrate B. Here, the screen mask 62 has a mesh portion 64 made of a water-repellent resin such as polyester resin. If the size of the opening of the mesh portion 64 is selected according to the size of the through portion, the second plating liquid L2 can be held in the gap S even if the screen mask 62 is pulled away from the substrate B after the film is formed. Therefore, the linear actuator 70 can move (raise) the container 15 in a direction to pull the screen mask 62 away from the substrate B while holding the second plating liquid L2 supplied to this gap S. As a result, the metal film F can be formed on the substrate B, and then the metal film F can be formed on a new substrate B without supplying the second plating liquid L2.

Each step of the film formation method shown in FIG. 2 will be described below with reference to the above-mentioned FIG. 1(a) and FIG. 3(a) and (b). In this film formation method, a screen mask 62 having perforations 68 of a predetermined pattern P formed thereon is sandwiched between the electrolyte membrane 13 and the substrate B, and a metal film F of the predetermined pattern P is formed on the surface of the substrate B by electrolytic plating.

First, the placement step S1 is performed. In this step, the substrate B is placed on the placement table 40. Specifically, the substrate B is accommodated in the recess 41 of the placement table 40.

Next, the pressing step S2 is performed. First, in this step, the linear actuator 70 is driven to move the container 15 toward the mounting table 40, and the mask structure 60 is brought into contact with the surface of the substrate B. As a result, the screen mask 62, in which the through-portions 68 of the predetermined pattern P are formed, can be placed on the substrate B. Next, as shown in FIG. 3B, the three-way valve 57 is operated so that the plating solution L (second plating solution) is supplied to the supply flow path 15e, and the on-off valve 58 is opened. In this state, the pump 83 and the suction pump 82 are driven. As a result, the second plating solution L2, which is the plating solution in the tank 90, is supplied to the surface of the screen mask 62 on the electrolyte membrane 13 side. With the substrate B covered with the screen mask 62, the second plating solution L2 is supplied to the gap S between the screen mask 62 and the electrolyte membrane 13. After the second plating solution L2 is supplied, the pump 83 and the suction pump 82 are stopped.

Next, after supplying the second plating solution L2, in this process, as shown in FIG. 3(b), the substrate B is covered with the screen mask 62, and the liquid pressure of the first plating solution L1 sealed in the container 15 by the electrolyte membrane 13 presses the substrate B with the screen mask 62 through the electrolyte membrane 13. Specifically, the three-way valve 57 is operated so that the plating solution L (first plating solution) is supplied to the supply port 15b, and the on-off valve 58 is closed. In this state, the pump 83 is driven. This allows the first plating solution L1 to be supplied to the storage space 15a, and the pressure of the plating solution L in the storage space 15a to be set to the pressure set by the pressure adjustment valve 55. As a result, the liquid pressure of the first plating solution L1 presses the substrate B with the screen mask 62 through the electrolyte membrane 13. This forces the second plating solution L2 contained in the gap S between the electrolyte membrane 13 and the screen mask 62 into the through-holes 68 of the screen mask 62, filling the through-holes 68 with the second plating solution L2. If the second plating solution L2 can be supplied, the suction pump 82 may be omitted.

In this way, the second plating liquid L2 can be supplied to the surface of the screen mask 62 by the liquid pressure of the first plating liquid L1 described later before the first plating liquid L1 passes through the electrolyte membrane 13. The second plating liquid L2 can be quickly filled into the through-hole portion 68 of the screen mask 62. In this embodiment, the first plating liquid L1 and the second plating liquid L2 are the same plating liquid L contained in the tank 90, so that the metal film F can be stably formed in the film formation process S3 described later.

When the screen mask 62 is placed on the surface of the substrate B, the plating solution can be easily filled into the through-holes 68 by creating a reduced pressure atmosphere around the screen mask 62. In addition, if an air vent groove or hole that connects the through-holes 68 to the outside is provided on the surface of the screen mask 62, the air in the through-holes 68 can be easily replaced by the plating solution.

Here, for example, the film forming apparatus 1 may be provided with a voltmeter (not shown) that measures the voltage between the anode 11 and the substrate B. In this case, the voltage acting between the anode 11 and the substrate B is measured by the voltmeter (not shown) while a constant current (current of a constant magnitude) is passed between the anode 11 and the substrate B. When the measured voltage becomes equal to or less than a preset value, it may be determined that the through portion 68 has been filled with the plating solution L, and the film forming process S3 may be started.

When the through-hole 68 of the screen mask 62 is not filled with plating solution, even if the power source 14 is controlled to pass a constant current between the anode 11 and the substrate B, the current does not flow easily, and the voltage value between the anode 11 and the substrate B becomes higher than the voltage during normal film formation. Therefore, in such a case, the current between the anode 11 and the substrate B is cut off, and the liquid pressure of the plating solution L in the container 15 is continuously maintained. After a predetermined time has elapsed, the voltage acting between the anode 11 and the substrate B is measured again in the same manner to determine whether the plating solution L has been filled in the through-hole 68. The current flow and voltage measurement are intermittently repeated until it is determined that the plating solution L has been filled in the through-hole 68.

Next, the film formation process S3 is performed. Here, as shown in FIG. 3(b), while the substrate B is pressed with a screen mask 62, a voltage from a power source 14 is applied between the substrate B and the anode 11 in contact with the plating solution L. As a result, the metal ions contained in the plating solution L pass through the electrolyte membrane 13, and a metal film F derived from the metal ions is formed on the substrate B in a predetermined pattern P.

In this way, by driving the pump 83 in the circulation path between the tank 90 storing the plating solution L and the container 15, the plating solution L is circulated while the metal film F is formed. The liquid pressure of the first plating solution L1 in the container space 15a also acts on the plating solution filled in the through-hole portion 68, so that a homogeneous metal film F can be formed under a constant liquid pressure. During film formation, the application of voltage causes water molecules contained in the plating solution L to pass through the electrolyte membrane 13 together with the metal ions passing through the electrolyte membrane 13, so that moisture is stably secured in the through-hole portion 68 of the screen mask 62. This allows the metal ions to be stably precipitated on the surface of the substrate B.

In the film formation step S3, a metal film F of a predetermined thickness is formed by energizing for a predetermined time, and then a separation step S4 is performed. In this step, the pump 83 is stopped and the liquid pressure of the first plating solution L1 in the container 15 is released (the liquid pressure is lowered to atmospheric pressure). The linear actuator 70 is driven to move the container 15 in a direction away from the mounting table 40, and the electrolyte membrane 13 is separated from the mask structure 60. In this embodiment, since the mask structure 60 is attached to the container 15, even if the weight of the first plating solution L1 acts on the electrolyte membrane 13, the excessive deformation of the electrolyte membrane 13 can be held by the screen mask 62. Furthermore, the container 15 can be separated from the substrate B while the second plating solution L2 is held in the gap between the screen mask 62 and the electrolyte membrane 13. The substrate B is removed from the mounting table 40, and the metal film F can be formed on a new substrate B without newly supplying the second plating solution L2.

In this embodiment, the mask structure 60 is attached to the container 15 to form an integrated unit, but for example, as shown in the modified example of FIG. 4(a), the container 15 and the mask structure 60 may be separate. In this case, the mask structure 60 is disposed so as to cover the surface of the substrate B, and the second plating liquid L2 is supplied from the supply mechanism 16 to the surface of the screen mask 62.

After that, as shown in FIG. 4(b), the container 15 is lowered to hold the second plating liquid L2 between the electrolyte membrane 13 and the screen mask 62. In this holding state, the pump 83 is driven to supply the first plating liquid L1 into the container space 15a. The first plating liquid L1 is adjusted to a predetermined liquid pressure in the container space 15a by the pressure adjustment valve 55. As a result, the liquid pressure of the first plating liquid L1 presses the surface of the substrate B with the screen mask 62 through the electrolyte membrane 13, and the second plating liquid L2 can be filled into the screen mask 62. In this state, a voltage of the power source 14 is applied between the anode 11 and the substrate B, so that a metal film F can be formed on the surface of the substrate B.

Examples of the present invention will be described below.
[Example]
A glass epoxy substrate was prepared as a substrate for film formation, in which a layer of glass fiber cloth was impregnated with epoxy resin. Copper foil was formed on the surface of this glass epoxy substrate. Next, a copper film was formed using the film formation apparatus shown in FIG. 1. A copper sulfate aqueous solution containing 1M _CuSO4 and _{0.2M H2SO4} was used as the plating solution. A Cu plate was used as the anode. Nafion (registered trademark) from DuPont was used as the electrolyte membrane. After supplying the second plating solution, the plating solution was filled into the through-portions formed in the screen mask with a total area of ¹⁸⁰⁰ mm2 while pressing the screen mask with the electrolyte membrane.

[Comparative Example]
The time until the plating solution filled the screen mask was measured in the same manner as in the example. The difference from the example is that the second plating solution was not supplied. When the time until the plating solution filled the penetration portion while the screen mask was pressed by the electrolyte membrane was measured, the filling time was 70 seconds.

From the above results, when the liquid pressure of the first plating solution contained in the container was applied to the electrolyte membrane while the second plating solution was being supplied, as in the Example, the second plating solution quickly filled the penetration portion of the screen mask. On the other hand, in the Comparative Example, the first plating solution contained in the container passed through the electrolyte membrane and moved to the screen mask, which is thought to have resulted in a longer filling time than in the Example.

1: Film forming device, 13: Electrolyte membrane, 14: Power source, 15: Container, 16: Supply mechanism, 40: Placement table, 61: Frame, 62: Screen mask, 64: Mesh portion, 65: Mask portion, 68: Penetration portion, B: Base material, L: Plating solution, L1: First plating solution, L2: Second plating solution, F: Metal film, P: Predetermined pattern

Claims (5)

A method for forming a metal film having a predetermined pattern on a substrate by electrolytic plating in a state in which a screen mask is sandwiched between an electrolyte membrane and the substrate, comprising the steps of:
The film forming method includes:
a pressing step of covering the base material with the screen mask having through-portions formed in a predetermined pattern, and pressing the base material with the screen mask via the electrolyte membrane by a liquid pressure of a first plating solution sealed in a container by the electrolyte membrane;
a film-forming step of applying a voltage between the anode in the container and the base material to pass metal ions contained in the first plating solution through the electrolyte membrane and form a metal coating derived from the metal ions on the base material in the predetermined pattern;
Including,
a second plating solution containing the metal ions is supplied to a surface of the screen mask on the electrolyte membrane side in the pressing step, and then the second plating solution is filled into the through-portion while pressing the substrate with the screen mask through the electrolyte membrane. the screen mask is attached to the housing at a position facing the electrolyte membrane such that a gap is formed between the screen mask and the electrolyte membrane,
2. The method for forming a metal coating according to claim 1, wherein in the pressing step, the second plating solution is supplied to the gap in a state in which the base material is covered with the screen mask. the screen mask includes a mesh portion made of resin and having openings formed in a lattice pattern, and a mask portion fixed to the mesh portion on a base material side and having the through-portions formed therein;
3. The method for forming a metal film according to claim 2, wherein after the film forming step, the container is separated from the base material while holding the second plating solution supplied to the gap. A film formation apparatus for forming a metal film having a predetermined pattern on a substrate by electrolytic plating in a state in which a screen mask is sandwiched between an electrolyte membrane and the substrate, comprising:
The film forming apparatus includes:
a container in which a first plating solution containing metal ions for film formation is contained and sealed with the electrolyte membrane;
a screen mask having the predetermined pattern of through-holes formed therein and covering the substrate;
a pressing mechanism that applies a liquid pressure of the first plating solution in the container to the electrolyte membrane to press the base material with the screen mask via the electrolyte membrane;
an anode contained in the container and spaced apart from the electrolyte membrane;
a power source for film formation that applies a voltage between the anode and the container;
a supply mechanism for supplying a second plating solution containing the metal ions to the surface of the screen mask on the electrolyte membrane side before the pressing mechanism presses the screen mask. the screen mask is attached to the housing at a position facing the electrolyte membrane such that a gap is formed between the screen mask and the electrolyte membrane,
The metal film forming apparatus according to claim 4 , wherein the supply mechanism supplies the second plating solution to the gap.

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