Metal film deposition method

Abstract

To provide a method of forming a metal film, capable of preventing a screen mask from being damaged upon being pressed by an electrolyte membrane, when the screen mask is used.SOLUTION: A substrate B is placed on a placement table 40. The substrate B is covered with a screen mask 62 having a penetrating part 68 of a prescribed pattern formed therein. The substrate B is pressed by an electrolyte membrane 13 via the screen mask 62 with a liquid pressure of a plating liquid L contacting with the electrolyte membrane 13. A voltage is applied between an anode 11 contacting with the plating liquid L and the substrate B to allow a metal ion included in the plating liquid L to pass through the electrolyte membrane 13 to form a metal film F derived from the metal ion in a prescribed pattern on the substrate B. The substrate B is formed with an outer edge Bc by an opposing face Ba opposing the screen mask 62, and a side face Bb. In the method of forming a metal film, a cushioning material 30 is arranged along the outer edge Bc prior to pressing the substrate B.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film forming method for forming a metal film in a predetermined pattern on the surface of a substrate. [Background technology]

[0002] Conventionally, metal coatings have been formed by depositing metal on the surface of a substrate by electrolytic plating (see, for example, Patent Document 1). In Patent Document 1, a film formation apparatus includes a container that contains a plating solution. The container has an opening that is sealed with an electrolyte membrane. The film formation apparatus further includes a pressing mechanism that presses the electrolyte membrane against the substrate using the hydraulic pressure of the plating solution.

[0003] Here, when a metallic underlayer with 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 hydraulic pressure of the electrolyte membrane. This allows a metal coating with the predetermined pattern to be formed on the underlayer. However, when a underlayer with the predetermined pattern is not formed on the substrate, it is also conceivable to use a masking material such as that shown in Patent Document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-125087 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-108586 Summary of the Invention [Problem to be solved by the invention]

[0005] When a screen mask is used as a masking material for film formation, the screen mask is sandwiched between the substrate and the electrolyte membrane. In this state, the electrolyte membrane, to which the hydraulic pressure of the plating solution acts, presses the screen mask to ensure close contact between the substrate and the screen mask. However, the substrate has an outer edge formed by the opposing surface and side surfaces facing the screen mask. Therefore, if the screen mask is pressed against the outer edge of the substrate, the screen mask may be damaged.

[0006] The present invention has been made in consideration of the above points, and aims to provide a method for forming a metal coating that can suppress damage to the screen mask when pressed by the electrolyte membrane, even when a screen mask is used. [Means for solving the problem]

[0007] In view of the above-described problems, the present invention provides a method for forming a metal film, which comprises placing a substrate on a mounting table, covering the substrate with a screen mask having perforations formed in a predetermined pattern, pressing the substrate with the electrolyte membrane via the screen mask using hydraulic pressure from a plating solution in contact with the electrolyte membrane, and applying a voltage between the substrate and an anode in contact with the plating solution, thereby causing metal ions contained in the plating solution to pass through the electrolyte membrane and forming a metal film derived from the metal ions on the substrate in the predetermined pattern. The substrate has an outer edge formed by a surface facing the screen mask and a side surface, and a cushioning material is placed along the outer edge before pressing the substrate.

[0008] According to the present invention, before pressing the substrate, a cushion material is placed along the outer edge of the substrate. As a result, when the electrolyte membrane presses the substrate via the screen mask due to the hydraulic pressure of the plating solution, the outer edge of the substrate is pressed against the screen mask via the cushion material. As a result, damage to the screen mask by the outer edge of the substrate can be suppressed.

[0009] As one example of the present invention, the mounting table may have a recess formed therein to accommodate the substrate, and when the substrate is placed, the substrate may be accommodated in the recess, and when the cushioning material is placed, the cushioning material may cover the gap formed between the side surface of the substrate and the side wall surface of the recess.

[0010] When the substrate is placed in the recess, a gap may form between the substrate and the mounting table. When this gap is formed and the substrate is pressed by the electrolyte membrane through the screen mask, the screen mask is likely to enter the gap. As a result, the screen mask comes into contact with the opening edge of the recess and is likely to be damaged. Therefore, in this example, by covering the gap with a cushioning material, it is possible to prevent the screen mask from entering the gap. As a result, damage to the screen mask can be reduced.

[0011] In one example of the present invention, the cushion material may be attached to the screen mask, and when the base material is covered with the screen mask, the cushion material may cover the gap.

[0012] According to this example, since the cushion material is attached to the screen mask in advance, it is possible to prevent the cushion material from shifting in position relative to the screen mask. Furthermore, when the base material is covered with the screen mask, the cushion material can simultaneously cover the gaps.

[0013] In one example of the present invention, the cushioning material may be attached to the base material along the outer edge before the base material is placed.

[0014] According to this example, the base material can be placed on the mounting table with the cushion material attached to the base material, so that the cushion material can be positioned at the same time as the base material is placed, and displacement of the cushion material relative to the base material can be prevented.

[0015] As one example of the present invention, the mounting table has a recess formed therein to accommodate the substrate, and by attaching the cushioning material to the substrate, the side surface of the substrate is covered with the cushioning material, and when the substrate is placed, the substrate can be accommodated in the recess while sandwiching the cushioning material between the side wall surface of the recess and the side surface of the substrate.

[0016] According to this example, the substrate is accommodated in a recess in the mounting table. At this time, a cushioning material is sandwiched between the side surface of the substrate and the side wall surface of the mounting table. This makes it possible to prevent a gap from being formed between them. As a result, damage to the screen mask due to a gap between the substrate and the mounting table can be prevented. Furthermore, it is possible to prevent the substrate from being misaligned with respect to the mounting table.

[0017] As one example of the present invention, the mounting table has a recess formed therein for accommodating the substrate, and the cushioning material is attached to the side wall surface of the recess. When the substrate is placed on the mounting table, the cushioning material may be sandwiched between the side wall surface of the recess and the side surface of the substrate, and the substrate may be accommodated in the recess.

[0018] According to this example, the substrate is accommodated in a recess in the mounting table. At this time, a cushioning material is sandwiched between the side surface of the substrate and the side wall surface of the mounting table. This makes it possible to prevent a gap from being formed between them. As a result, damage to the screen mask due to the gap between the substrate and the mounting table can be prevented, and displacement of the substrate relative to the mounting table can be prevented.

[0019] As one example of the present invention, the peripheral edge of the screen mask may be fixed to a frame on the electrolyte membrane side, and the base material may be covered with the screen mask within the frame.

[0020] In this example, the screen mask is supported by the frame on the electrolyte membrane side of the frame. Therefore, the electrolyte membrane can press the screen mask while suppressing deformation of the electrolyte membrane due to the pressure of the plating solution. Furthermore, because the screen mask covers the substrate within the frame, deformation of the screen mask due to pressure from the electrolyte membrane can be suppressed. [Effects of the Invention]

[0021] According to the present invention, even when a screen mask is used, damage to the screen mask when pressed by the electrolyte membrane can be suppressed. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view showing an example of a metal film forming apparatus according to an embodiment of the present invention. [Figure 2] 2 is a schematic perspective view showing the positional relationship between a mask structure, a cushion material, and a substrate on which a metal film is formed in the film forming apparatus shown in FIG. 1. FIG. [Figure 3A] FIG. 3 is a partially enlarged cross-sectional view taken along line AA shown in FIG. 2. [Figure 3B] FIG. 3B is an enlarged cross-sectional view of part C in FIG. 3A. [Figure 4] FIG. 2 is a schematic cross-sectional view for explaining film formation by the film formation apparatus shown in FIG. [Figure 5A] FIG. 5 is a cross-sectional view of a main part of FIG. 4. [Figure 5B] FIG. 5B is an enlarged cross-sectional view of part C in FIG. 5A. [Figure 6] 1 is a flowchart illustrating an example of a method for forming a metal film using a film forming apparatus according to an embodiment of the present invention. [Figure 7A] 1 is a schematic cross-sectional view of a film forming apparatus used in a film forming method according to a first modified example. [Figure 7B] FIG. 7B is a schematic cross-sectional view for explaining a film formation method using the film formation apparatus of FIG. 7A. [Figure 8A] 10 is a schematic cross-sectional view of a film forming apparatus used in a film forming method according to Modification 2. FIG. [Figure 8B] FIG. 11 is a schematic cross-sectional view of a film forming apparatus used in a film forming method according to a third modification. [Figure 9A] 10 is a schematic cross-sectional view illustrating a cushioning material used in a film forming method according to a fourth modification. FIG. [Figure 9B] 10 is a schematic cross-sectional view illustrating a cushioning material used in a film forming method according to Modification 5. FIG. [Figure 10A] 13 is a schematic cross-sectional view illustrating a cushioning material used in a film forming method according to Modification 6. FIG. [Figure 10B] 13 is a schematic cross-sectional view illustrating a cushioning material used in a film forming method according to Modification 7. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] 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.

[0024] 1, the film formation apparatus 1 is a film formation apparatus that forms a metal coating F of a predetermined pattern P on a substrate B by electrolytic plating with a mask structure 60 sandwiched between an electrolyte membrane 13 and the substrate B. Specifically, the film formation 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.

[0025] The film formation apparatus 1 includes a container 15 that contains an anode 11 and a plating solution L, a mounting table 40 on which a substrate B is placed, and a mask structure 60. During film formation, the mask structure 60 is placed on the mounting table 40 together with the substrate B. The electrolyte membrane 13 is disposed between the mask structure 60 and the anode 11.

[0026] The film forming apparatus 1 includes a linear actuator 70 that raises and lowers the container 15. In this embodiment, for convenience of explanation, it is assumed that the electrolyte membrane 13 is disposed below the anode 11, and the mask structure 60 and the substrate B are disposed further below that. However, as long as the metal coating F can be formed on the surface of the substrate B, the positional relationship is not limited to this.

[0027] 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 substrate B has a side surface Bb formed on its outer periphery. The material of the substrate B is not particularly limited as long as it functions as a cathode (i.e., a conductive surface). 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 forming the metal coating F, the base layer other than the portion where the metal coating F is formed is removed by etching or the like. This allows a wiring pattern made of the metal coating F to be formed on the surface of the insulating substrate.

[0028] The anode 11 is, for example, a non-porous (e.g., non-porous) anode made of the same metal as the metal of the metal coating. The anode 11 has a block or flat plate shape. 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 forming a film using only 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.

[0029] The plating solution L is a solution containing the metal of the metal coating to be formed in an ionic state. Examples of such metals include copper, nickel, gold, silver, and iron. 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, or pyrophosphoric acid. Examples of the solvent for the solution include water and alcohol. For example, when the metal is copper, the plating solution L can be an aqueous solution containing copper sulfate, copper pyrophosphate, or the like.

[0030] The electrolyte membrane 13 is a membrane that can be impregnated (contain) metal ions together with the plating solution L by contacting it 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 it allows the metal ions of the plating solution L to migrate to the substrate B side when a voltage is applied from the power source 14. Examples of materials for the electrolyte membrane 13 include resins with ion exchange properties, such as fluororesins such as Nafion (registered trademark) manufactured by DuPont. The thickness of the electrolyte membrane 13 is preferably in the range of 20 μm to 200 μm. More preferably, the thickness is in the range of 20 μm to 60 μm.

[0031] The container 15 is made of a material that is insoluble in the plating solution L. The container 15 has a storage space 15a that stores the plating solution L. The anode 11 is disposed in the storage space 15a of the container 15. An opening 15d is formed on the side of the storage space 15a that faces the substrate B. The opening 15d of the container 15 is covered with an electrolyte membrane 13. Specifically, the periphery of the electrolyte membrane 13 is sandwiched between the container 15 and the frame 17. This allows the plating solution L in the storage space 15a to be sealed by the electrolyte membrane 13.

[0032] 1 and 4, the linear actuator 70 raises and lowers the housing 15 so that the electrolyte membrane 13 and the mask structure 60 can be moved toward and away 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 using a ball screw or the like (not shown). However, instead of the electric actuator, a hydraulic or pneumatic actuator may be used.

[0033] The container 15 is formed with a supply flow path 15b that supplies the plating solution L to the container space 15a. Furthermore, the container 15 is formed with a discharge flow path 15c that discharges the plating solution L from the container space 15a. The supply flow path 15b and the discharge flow path 15c are holes that communicate with the container space 15a. The supply flow path 15b and the discharge flow path 15c are formed on either side of the container space 15a. The supply flow path 15b is connected to a liquid supply pipe 50. The discharge flow path 15c is fluidly connected to a liquid discharge pipe 52.

[0034] The film forming apparatus 1 further includes a liquid tank 90, a liquid supply pipe 50, a liquid discharge pipe 52, and a pump 80. As shown in FIG. 1 , the liquid tank 90 contains a plating solution L. The liquid supply pipe 50 connects the liquid tank 90 to the accommodation body 15. The liquid supply pipe 50 is provided with a pump 80. The pump 80 supplies the plating solution L from the liquid tank 90 to the accommodation body 15. The liquid discharge pipe 52 connects the liquid tank 90 to the accommodation body 15. The liquid discharge pipe 52 is provided with a pressure adjustment valve 54. The pressure adjustment valve 54 adjusts the pressure (liquid pressure) of the plating solution L in the accommodation space 15a to a predetermined pressure.

[0035] In this embodiment, the plating solution L is sucked from the liquid tank 90 into the liquid supply pipe 50 by driving the pump 80. The sucked plating solution L is pressure-fed from the supply flow path 15b to the accommodation space 15a. The plating solution L in the accommodation space 15a is returned to the liquid tank 90 via the discharge flow path 15c. In this manner, the plating solution L is circulated within the film forming apparatus 1.

[0036] Furthermore, by continuing to drive the pump 80, the liquid pressure of the plating solution L in the accommodation space 15a can be maintained at a predetermined pressure by the pressure regulating valve 54. The pump 80 presses the mask structure 60 with the electrolyte membrane 13 acting on the liquid pressure of the plating solution L. However, the pressing mechanism is not particularly limited as long as it can press the mask structure 60 with the electrolyte membrane 13. Instead of the pump 80, an injection mechanism consisting of a piston and a cylinder that injects the plating solution L may be used.

[0037] The mounting table 40 is formed of, for example, a conductive material (e.g., metal). The mounting table 40 has a first recess 41 and a second recess 42 formed therein. The first recess 41 is a recess that accommodates the substrate B. The second recess 42 is a recess that accommodates the mask structure 60 with the substrate B accommodated in the first recess 41. Note that the "recess" in the present invention corresponds to the first recess 41.

[0038] Fig. 2 is a schematic perspective view of the mask structure 60 of the film forming apparatus 1 shown in Fig. 1, and a schematic perspective view of the cushion material 30 and the substrate B on which the metal film F is formed. Fig. 3A is a partially enlarged cross-sectional view taken along the line AA shown in Fig. 2, and Fig. 3B is an enlarged cross-sectional view of part C in Fig. 3A.

[0039] The mask structure 60 includes a frame body 61 and a screen mask 62. The screen mask 62 has through-holes 68 formed therein 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 flexibility of approximately 50 μm to 400 μm. The screen mask 62 is supported by the frame body 61 on the substrate B side of the frame body 61.

[0040] The mesh portion 64 is fixed to the frame 61. The mesh portion 64 is stretched with a predetermined tension so as to cover the opening of the frame 61. The mesh portion 64 has a plurality of openings 64c, 64c, ... formed in a lattice pattern. Specifically, as shown in FIG. 3B , the mesh portion 64 is a mesh-like portion in which a plurality of oriented wires 64a, 64b are woven so as to intersect. The plurality of wires 64a, 64a are arranged at intervals, and the plurality of intersecting wires 64b, 64b are arranged at intervals. As a result, a plurality of openings 64c, 64c, ... are formed in the mesh portion 64 in a lattice pattern. The material of the wires 64a, 64b is not particularly limited as long as it is corrosion-resistant to the plating solution L. Examples of materials for the wires 64a, 64b include metal materials such as stainless steel and resin materials such as polyester.

[0041] The mask portion 65 is fixed to the mesh portion 64 on the substrate B side of the mesh portion 64. The mask portion 65 has through-holes 68 formed therein according to a predetermined pattern P. The mask portion 65 is a portion that adheres closely to the substrate B during membrane 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 closely to the substrate B. It is preferable that the mask portion 65 undergoes compressive elastic deformation due to pressure from the electrolyte membrane 13. Examples of materials for the mask portion 65 include resin materials such as acrylic resin, vinyl acetate resin, polyvinyl resin, polyimide resin, and polyester resin. The screen mask 62 having the predetermined pattern P can be manufactured using a general silkscreen manufacturing technique using an emulsion. Therefore, a detailed description of the manufacturing method of the screen mask 62 will be omitted.

[0042] The frame 61 supports a peripheral edge 64d of the screen mask 62 on the substrate B side (the mounting table 40 side) of the frame 61. Specifically, the peripheral edge 64d of 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 a thermoplastic resin. The frame 61 is formed, for example, by punching a metal plate and has a thickness of approximately 1 mm to 3 mm. Note that in FIG. 3A and other figures, the thickness of the frame 61 is depicted as being thicker than its actual thickness for ease of explanation.

[0043] The cushion material 30 is disposed along the outer edge portion Bc of the base material B when pressing the base material B. The outer edge portion Bc is the edge portion (edge ​​portion) of the base material B formed by the opposing surface Ba of the base material B facing the screen mask 62 and the side surface Bb of the base material B.

[0044] Here, "arranging a cushioning material along the outer edge" as used in the present invention can refer to the following cases (1) to (3). Specifically, (1) is a case where the cushioning material 30 is arranged from the opposing surface Ba of the base material B along the outer edge Bc of the base material B. This embodiment and Modified Examples 1 to 3 described below correspond to case (1). In addition, (2) is a case where the cushioning material 30 is arranged from the side surface Bb along the outer edge Bc of the base material B. Modified Examples 6 and 7 described below correspond to case (2). (3) is a case that includes cases (1) and (2). Modified Examples 4 and 5 described below correspond to case (3).

[0045] As shown in FIGS. 2 and 3A, the cushion material 30 is arranged along the outer edge portion Bc of the base material B. A rectangular opening 31 is formed in the cushion material 30. Inside the opening 31, a through portion 68 is arranged according to a predetermined pattern P. When the base material B is placed on the mounting table 40, a gap S is formed between the side surface Bb of the base material B and the side wall surface 41a of the first recess 41. The cushion material 30 is sized to cover the gap S. Specifically, the cushion material 30 is arranged so as to span between the opposing surface Ba of the base material B and the surface (opposing surface) 40c of the mounting table 40.

[0046] The cushion material 30 is made of an elastic material that is softer than the material of the substrate B. The material of the cushion material 30 is not particularly limited as long as it can avoid damaging the screen mask 62. It is preferable that the cushion material 30 undergoes compressive elastic deformation due to pressure from the electrolyte membrane 13 (specifically, pressure from the cushion material 30). Examples of materials for the cushion material 30 include rubber materials such as silicone rubber (PMDS) or ethylene propylene diene rubber (EPDM). The hardness of the rubber material is preferably HS100 or less, more preferably HS50 or less, in Shore A hardness. Note that a "soft elastic material" refers to a material that has a relatively low hardness, measured using a durometer of a specified standard, and a low Young's modulus in a tensile test. Considering the adhesion between the mask portion 65 and the substrate B, it is preferable that the thickness of the cushion material 30 is thinner than the thickness of the screen mask. It is preferable that the material of the cushion material 30 is made of a material that is softer than the material of the mask portion 65.

[0047] 1 to 6, a film formation method using the film formation apparatus 1 will be described. First, a placement step S1 is performed as shown in FIG. 6. In this step, the substrate B is placed on the mounting table 40. Specifically, the substrate B is accommodated in the first recess 41 of the mounting table 40. At this time, the alignment of the substrate B with respect to the anode 11 attached to the housing 15 is adjusted, and the temperature of the substrate B may also be adjusted.

[0048] At this time, as shown in Fig. 3A, a gap S is formed between the side surface Bb of the base material B and the side wall surface 41a of the first recess 41. Therefore, in the arrangement step S1, as shown in Fig. 1 and Fig. 3A, the cushion material 30 is arranged along the outer edge portion Bc of the base material B. Specifically, the cushion material 30 covers the gap S from the screen mask 62 side (electrolyte membrane 13 side).

[0049] Next, the mask structure 60 is placed in the second recess 42 of the mounting table 40, and the substrate B is covered with the screen mask 62. The cushion material 30 is sandwiched between the screen mask 62 and the opposing surface Ba of the substrate B. The cushion material 30 is also sandwiched between the screen mask 62 and the opposing surface 40a of the mounting table 40.

[0050] Next, a pressing step S2 is performed. In this step, the electrolyte membrane 13 presses the substrate B through the screen mask 62 by the hydraulic pressure of the plating solution L in contact with the electrolyte membrane 13. First, the linear actuator 70 is driven. This causes the container 15 to descend toward the mask structure 60 from the state shown in FIG. 1 to the state shown in FIG. 4.

[0051] Next, the pump 80 is driven. This supplies the plating solution L to the accommodation space 15a of the accommodation body 15. Because the pressure regulating valve 54 is provided in the liquid discharge pipe 52, the liquid pressure of the plating solution L in the accommodation space 15a is maintained at a predetermined pressure. As a result, as shown in FIG. 4, the liquid pressure of the plating solution L causes the electrolyte membrane 13 to deform toward the internal space 69 of the frame 61, and the screen mask 62 can be sandwiched between the electrolyte membrane 13 and the substrate B. Furthermore, the electrolyte membrane 13, to which the liquid pressure of the plating solution L acts, can press against the mask structure 60.

[0052] 4 and 5A, a peripheral edge 62a of the screen mask 62 is supported by the frame 61 on the substrate B side of the frame 61. Therefore, this pressure allows the screen mask 62 to be tightly attached to the surface of the substrate B. If the mask portion 65 is made of a rubber material, the mask portion 65 is compressed and elastically deformed by the liquid pressure of the plating solution L, improving the adhesion between the mask portion 65 and the substrate B.

[0053] Furthermore, as the pressure on the electrolyte membrane 13 continues, as shown in Figures 5A and 5B, the seepage liquid (plating liquid) La that seeps out from the electrolyte membrane 13 swollen by the plating liquid L fills the through-holes 68 formed in the screen mask 62.

[0054] In this embodiment, before pressing the substrate B, the cushion material 30 is placed along the outer edge portion Bc of the substrate B. Therefore, when the electrolyte membrane 13 presses the substrate B via the screen mask 62 due to the hydraulic pressure of the plating solution L, the outer edge portion Bc of the substrate B is pressed by the screen mask 62 via the cushion material 30. The cushion material 30 elastically deforms in the thickness direction and absorbs the pressing force of the screen mask 62. As a result, the outer edge portion Bc of the substrate B prevents stress from concentrating on the screen mask 62, and damage to the screen mask 62 can be suppressed.

[0055] In particular, when the substrate B is accommodated in the first recess 41, a gap S may be formed between the substrate B and the mounting table 40. When this gap S is formed, if the electrolyte membrane 13 presses the substrate B via the screen mask 62, the screen mask 62 is likely to enter the gap S. As a result, the screen mask 62 comes into contact with the opening edge of the first recess 41, and the screen mask 62 is likely to be damaged. However, by covering the gap S with the cushion material 30, the screen mask 62 can be prevented from entering the gap S. As a result, damage to the screen mask 62 can be reduced.

[0056] Next, the film-forming step S3 is performed. In this step, the pressing state by the electrolyte membrane 13 in the pressing step S2 is maintained, and a metal film F is formed. Specifically, a voltage is applied between the anode 11 and the substrate B. This causes metal ions contained in the plating solution L to pass through the electrolyte membrane 13. The metal ions that have passed through the electrolyte membrane 13 migrate to the surface of the substrate B via the oozing liquid La, and are reduced on the surface of the substrate B. The oozing liquid La filled in the through-portion 68 is sealed inside the through-portion 68 by the electrolyte membrane 13, so that a metal film F of a predetermined pattern can be formed on the surface of the substrate B (see FIG. 2). The metal film F is a film derived from metal ions.

[0057] Furthermore, the exudation liquid La is uniformly pressurized by the pressure of the electrolyte membrane 13, so that a uniform metal coating F can be formed. After the film is formed, the plating solution L is removed from the container 15, and the container 15 is raised to separate the electrolyte membrane 13 from the substrate B, and the substrate B is removed from the mounting table 40. When manufacturing wiring using the metal coating F, it is sufficient to etch the conductive base layer formed on the surface of the insulating substrate (insulating substrate) B.

[0058] <Modification> Fig. 7A is a schematic cross-sectional view of a film formation apparatus used in a film formation method according to Modification 1. Fig. 7B is a schematic cross-sectional view for explaining a film formation method using the film formation apparatus of Fig. 7A. Modification 1 differs from the embodiment shown in Figs. 1 and 4 in the structure of the mask structure 60 and the structure of the mounting table 40. Therefore, only the differences from the above-described embodiment will be described, and detailed descriptions of similar configurations will be omitted.

[0059] 7A, a peripheral edge 62a of the screen mask 62 is fixed to the frame body 61 on the electrolyte membrane 13 side of the frame body 61. Therefore, an internal space 69 of the frame body 61 is open to the mounting table 40 side. The screen mask 62 is larger than that in the above-described embodiment and also covers the opposing surface 40a of the mounting table 40. However, no through portion 68 is formed in the portion that contacts the opposing surface 40a of the mounting table 40. A recessed groove 43 that accommodates the frame body 61 is formed in the mounting table 40. However, in the first modification, the mounting table 40 does not have a second recessed portion 42 that accommodates the mask structure 60.

[0060] A film formation method using this film formation apparatus 1 will be described below. First, in the arrangement step S1, the substrate B is arranged on the mounting table 40. Specifically, the substrate B is accommodated in the first recess 41 of the mounting table 40. Next, the cushion material 30 is arranged along the outer edge portion Bc of the substrate B. Specifically, the cushion material 30 covers the gap S from the screen mask 62 side (electrolyte membrane 13 side). Next, the screen mask 62 covers the substrate B. At this time, the frame body 61 of the mask structure 60 is accommodated in the recessed groove 43 of the mounting table 40. Furthermore, as shown in FIG. 7B, the frame body 61 and the mounting table 40 are clamped by a clamper 93. Thereafter, the pressing step S2 and the film formation step S3 are similarly performed.

[0061] In this first modification, as described above, the cushion material 30 can also prevent damage to the screen mask 62. In this first modification, the peripheral edge of the screen mask 62 is supported by the frame 61 on the electrolyte membrane 13 side of the frame 61. Therefore, as shown in FIG. 7B , the electrolyte membrane 13 can press the screen mask 62 while preventing deformation of the electrolyte membrane 13 due to the liquid pressure of the plating solution L. Furthermore, because the screen mask 62 covers the substrate B within the frame 61, deformation of the screen mask 62 due to the pressure of the electrolyte membrane 13 can be prevented.

[0062] 8A and 8B are schematic cross-sectional views of a film formation apparatus used in the film formation methods according to Modifications 2 and 3. In these modifications, a cushion material 30 is attached to a screen mask 62 of a mask structure 60. Differences from the above-described embodiment will be described, and detailed descriptions of similar configurations will be omitted.

[0063] As shown in FIG. 8A , in Modification 2, the mask structure 60 is attached to the frame 17 of the housing 15. A peripheral edge 62a of the screen mask 62 is fixed to the frame 61 on the electrolyte membrane 13 side of the frame 61. Therefore, an internal space 69 of the frame 61 is open to the mounting table 40 (substrate B side). The cushion material 30 is attached to the screen mask 62. With the substrate B accommodated in the first recess 41, the opposing surface Ba of the substrate B protrudes from the opposing surface 40a of the mounting table 40. This allows the screen mask 62 to be in uniform contact with the opposing surface Ba of the substrate B.

[0064] As shown in FIG. 8B , in Modification 3, the mask structure 60 is attached to the frame 17 of the housing body 15. A peripheral edge 62 a of the screen mask 62 is fixed to the frame 61 on the side of the mounting table 40 (substrate B) relative to the frame 61. In this modification, the electrolyte membrane 13 is attached to the housing body 15 by the frame 61. Specifically, the peripheral edge of the electrolyte membrane 13 is sandwiched between the frame 61 and the housing body 15. This allows the electrolyte membrane 13 to be attached to the housing body 15 when the frame 61 is attached to the housing body 15. However, as in the above-described embodiment, the electrolyte membrane 13 may be attached to the housing body 15 using the frame 17. The cushion material 30 is attached to the screen mask 62 on the side of the mounting table 40 relative to the screen mask 62. In Modification 3, the electrolyte membrane 13 deforms toward the internal space 69 of the frame 61 due to the hydraulic pressure of the plating solution L.

[0065] A film formation method using the film formation apparatus 1 according to Modifications 2 and 3 will be described below. First, in the placement step S1, the substrate B is placed on the mounting table 40. Specifically, the substrate B is accommodated in the first recess 41 of the mounting table 40. In these modifications, the accommodation body 15 is then lowered. This causes the substrate B to be covered with the screen mask 62. At this time, the cushion material 30 is attached to the screen mask 62. Therefore, the opposing surface Ba of the substrate B is covered with the screen mask 62, and the cushion material 30 can cover the gap S. Furthermore, because the cushion material 30 is attached to the screen mask 62 in advance, it is possible to prevent the cushion material 30 from shifting position relative to the screen mask 62.

[0066] In the second modification, the electrolyte membrane 13 is hardly deformed by the liquid pressure of the plating solution L. This makes it possible to prevent the electrolyte membrane 13 from becoming loose due to repeated use.

[0067] 9A and 9B are schematic cross-sectional views illustrating cushion materials used in the film forming methods according to Modifications 4 and 5. In these modifications, a cushion material 30 is attached to a substrate B. Differences from the above-described embodiment will be described, and detailed descriptions of similar configurations will be omitted.

[0068] 9A, in Modification 4, a cushion material 30 is attached to the outer edge portion Bc of the base material B. Specifically, a part of the opposing surface Ba of the base material B and a part of the side surface Bb of the base material B are covered with the cushion material 30.

[0069] The mounting table 40 has a first recess 41 formed therein to accommodate the substrate B. As in the embodiment shown in FIG. 1, the mounting table 40 may have a second recess formed therein to accommodate the mask structure 60. When the substrate B is accommodated in the first recess 41, the cushion material 30 covers the gap S formed between the side surface Bb of the substrate B and the side wall surface 41a of the first recess 41. In the fourth modification, when the substrate B is accommodated in the first recess 41, the opposing surface Ba of the substrate B protrudes from the opposing surface 40a of the mounting table 40. This allows the screen mask 62 to be in uniform contact with the opposing surface Ba of the substrate B.

[0070] 9B, in the fifth modification, a cushion material 30 is attached to the outer edge portion Bc of the base material B. Specifically, a portion of the facing surface Ba of the base material B and a side surface Bb of the base material B are covered with the cushion material 30. When the base material B is accommodated in the first recess 41, the facing surface 40a of the mounting table 40 is covered with a portion of the cushion material 30. Furthermore, a portion of the cushion material 30 enters the gap formed between the side surface Bb of the base material B and the side wall surface 41a of the first recess 41.

[0071] A film formation method using the film formation apparatus 1 according to Modifications 4 and 5 will be described below. First, in the arrangement step S1, before the substrate B is placed on the mounting table 40, the cushion material 30 is attached to the substrate B along the outer edge portion Bc of the substrate B. As shown in FIG. 9A , in Modification 4, by attaching the cushion material 30 to the substrate B, the opposing surface Ba of the substrate B and the side surface Bb of the substrate B along the outer edge portion Bc of the substrate B are covered with the cushion material 30. With the substrate B accommodated in the first recess 41 of the mounting table 40, the cushion material 30 is arranged so as to cover the gap S.

[0072] 9B , in Modification 5, by attaching the cushion material 30 to the base material B, the cushion material 30 covers the opposing surface Ba of the base material B and the side surface Bb of the base material B along the outer edge portion Bc of the base material B. Next, when placing the base material B, the cushion material 30 is sandwiched between the side wall surface 41a of the first recess 41 and the side surface Bb of the base material B, and the base material B is accommodated in the first recess 41. The base material B can be fixed to the mounting table 40 by elastic deformation of the sandwiched cushion material 30.

[0073] In this way, in Modification 4, the gap S can be covered with the cushion material 30, thereby preventing damage to the screen mask 62. In Modification 5, there is no gap between the substrate B and the mounting table 40, thereby preventing damage to the screen mask 62.

[0074] In these modified examples, the base material B can be placed on the mounting table 40 with the cushion material 30 attached to the base material B. Therefore, when the base material B is placed, the cushion material 30 is simultaneously placed, and it is possible to prevent the cushion material 30 from shifting in position relative to the base material B. Furthermore, in modified example 5, the cushion material 30 is sandwiched between the side wall surface 41a of the first recess 41 and the side surface Bb of the base material B. As a result, it is possible to prevent the base material from shifting in position relative to the mounting table 40.

[0075] 10A and 10B are schematic cross-sectional views illustrating cushion materials used in the film forming methods according to Modifications 6 and 7. In these modifications, cushion materials 30 are attached to a mounting table 40. Differences from the above-described embodiment will be described, and detailed descriptions of similar configurations will be omitted.

[0076] 10A and 10B, in Modifications 6 and 7, a first recess 41 for accommodating the substrate B is formed in the mounting table 40. As in the embodiment shown in FIG. 1, a second recess for accommodating the mask structure 60 may be formed in the mounting table 40.

[0077] In Modifications 6 and 7, a cushion material 30 is attached to the side wall surface 41a of the first recess 41. Specifically, as shown in FIG. 10 , in Modification 6, the side wall surface 41a of the first recess 41 is covered with the cushion material 30. Note that, when the substrate B is housed, the cushion material 30 may protrude from the opposing surface Ba of the substrate B and the opposing surface 40a of the mounting table 40. As shown in FIG. 10B , in Modification 7, the cushion material 30 is attached along the opening edge 41b of the first recess 41. Specifically, the side wall surface 41a of the first recess 41 and the opposing surface 40a of the mounting table 40 are covered with the cushion material 30.

[0078] A film formation method using the film formation apparatus 1 according to the sixth and seventh modifications will be described below. First, in the placement step S1, before the substrate B is placed on the mounting table 40, the cushion material 30 is attached to the mounting table 40. In these modifications, when the substrate B is placed, the cushion material 30 is sandwiched between the side wall surface 41a of the first recess 41 and the side surface Bb of the substrate B, and the substrate B is accommodated in the first recess 41. The substrate B can be fixed to the mounting table 40 by elastic deformation of the sandwiched cushion material 30.

[0079] Furthermore, in these modified examples, by attaching the cushion material 30 to the side wall surface 41a of the mounting table 40, the cushion material 30 can cover the base material B from the side surface Bb of the base material B along the outer edge portion Bc of the base material B. Furthermore, since there is no gap S between the side surface Bb of the base material B and the side wall surface 41a of the mounting table 40, the screen mask 62 does not get into the gap. As a result, damage to the screen mask 62 can be prevented.

[0080] In these modified examples, when the base material B is placed, the cushion material 30 can be placed on the base material B at the same time. Furthermore, it is possible to prevent the cushion material 30 from shifting in position relative to the base material B, and it is also possible to prevent the base material B from shifting in position relative to the mounting table 40. [Example]

[0081] The invention is illustrated by the following examples.

[0082] [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 according to the modified example shown in FIG. 7A. Silicone rubber (Shore A hardness HS50) with a thickness of 0.1 mm was used as the cushioning material. A copper sulfate aqueous solution (Cu-BRITE-SED) manufactured by JCU Corporation was used as the plating solution, and a Cu plate was used as the anode. Nafion (registered trademark) manufactured by DuPont was used as the electrolyte membrane. The electrochemical film formation conditions were a plating solution temperature of 42°C, a current density of 7 A / dm 2 The copper film was formed with a cumulative pressing time of 500 seconds. The film was formed under two conditions: the liquid pressure of the plating solution was 0.6 MPa and 1 MPa.

[0083] [Comparative Example] A copper film was formed in the same manner as in Example 1. The difference from Example 1 was that no cushioning material was used.

[0084] The state of the electrolyte membrane after membrane formation was confirmed for the membrane formation apparatuses of the Example and Comparative Example. Under both hydraulic pressure conditions, the screen mask of the Example was not damaged. On the other hand, under both hydraulic pressure conditions, the screen mask of the Comparative Example was torn.

[0085] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the film forming apparatus according to the above embodiments, and includes all aspects encompassed by the concept and scope of the present invention. Furthermore, each configuration may be appropriately and selectively combined to achieve the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be appropriately modified depending on the specific aspects of the present invention. [Explanation of symbols]

[0086] 1: film forming device, 30: cushion material, 13: electrolyte membrane, 40: mounting table, 41: first recess, 60: mask structure, 61: frame, 62: screen mask, 64: mesh portion, 65: mask portion, 68: penetration portion, B: substrate, Ba: opposing surface, Bc: outer edge portion, F: metal film, L: plating solution

Claims

1. The substrate is placed on a mounting table, Covering the substrate with a screen mask having a predetermined pattern of through-holes; pressing the electrolyte membrane against the substrate through the screen mask by hydraulic pressure of the plating solution in contact with the electrolyte membrane; a method for forming a metal film, comprising applying a voltage between an anode in contact with the plating solution and the substrate, thereby causing metal ions contained in the plating solution to pass through the electrolyte membrane, and forming a metal film derived from the metal ions on the substrate in the predetermined pattern, the substrate has an outer edge portion formed by a surface facing the screen mask and a side surface, a recess for accommodating the substrate is formed in the mounting table; The screen mask comprises: a mesh portion in which a plurality of wires are woven together so as to cross each other, and a plurality of openings are formed in a lattice pattern; a mask portion fixed to the mesh portion on the substrate side of the mesh portion, the mask portion having the through-portion formed therein, and the mask portion being in close contact with the substrate when the metal coating film is formed, a periphery of the screen mask is fixed to the frame body so that the screen mask covers the opening of the frame body; In the film forming method, When placing the substrate, the substrate is accommodated in the recess; before pressing the substrate, a cushion material is placed between the screen mask, the substrate, and the mounting table along the outer edge portion, with the cushion material covering a gap formed between the side surface of the substrate and a side wall surface of the recess, and the cushion material has a thickness smaller than that of the screen mask; The method for forming a metal film, wherein the cushioning material is made of a material softer than the mask portion.

2. The cushioning material further has a portion that enters the gap when the metal coating is formed, before placing the base material, the cushion material is attached to the base material so that the recessed portion covers the side surface of the base material; 2. The method for forming a metal coating according to claim 1, wherein when placing the substrate, the substrate is accommodated in the recess while sandwiching the recessed portion of the cushion material between the side wall surface of the recess and the side surface of the substrate.

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