JP2024061016A - Metal film deposition equipment - Google Patents

Abstract

[Problem] To provide a metal coating forming device that can suppress damage to an electrolyte membrane when pressed, even when a mask structure is used. [Solution] A film forming device 1 is provided with a pressing mechanism that presses a mask structure 60 with an electrolyte membrane 13 by the liquid pressure of a plating solution L. The mask structure 60 includes a screen mask 62 having through-holes 68 formed according to a predetermined pattern, and a frame 61 that supports a peripheral edge 62a of the screen mask 62 on the substrate B side. An inner covering portion 66A made of an elastic material softer than the material of the frame 61 is formed on the frame 61 along an opening edge 61a that contacts the electrolyte membrane 13. [Selected Figure] Figure 3A

Description

The present invention relates to a film forming device that forms a metal film in a predetermined pattern on the surface of a substrate.

Conventionally, there have been proposed film-forming devices that deposit metal on the surface of a substrate to form a metal film (for example, Patent Document 1). In Patent Document 1, the film-forming device includes a container that contains a plating solution. An opening is formed in the container, and the opening is sealed with an electrolyte membrane. The film-forming device 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 2016-125087 A JP 2016-108586 A

Here, when a film is formed using a mask structure having a screen mask as a masking material, the mask structure 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 mask structure is pressed by the electrolyte membrane acting on by the hydraulic pressure of the plating solution. However, since the frame supporting the periphery of the screen mask is supported on the substrate side, the electrolyte membrane is pressed against the opening edge of the frame, which may damage the electrolyte membrane.

The present invention was made in consideration of these points, and aims to provide a metal film forming device that can suppress damage to the electrolyte membrane when pressed, even when a mask structure is used.

In view of the above problems, the metal film forming apparatus according to the present invention is a film forming apparatus that forms a metal film of a predetermined pattern on a substrate by electrolytic plating with a mask structure sandwiched between an electrolyte membrane and the substrate. The film forming apparatus includes a pressing mechanism that presses the mask structure with the electrolyte membrane by the hydraulic pressure of a plating solution. The mask structure includes a screen mask having a through portion formed according to the predetermined pattern, and a frame that supports the periphery of the screen mask on the substrate side. The frame has an inner covering portion made of an elastic material softer than the material of the frame formed along an opening edge that contacts the electrolyte membrane.

According to the present invention, first, the mask structure is sandwiched between the electrolyte membrane and the substrate, and the electrolyte membrane acting on the hydraulic pressure of the plating solution is pressed against the mask structure by the pressing mechanism. The periphery of the screen mask is supported by a frame on the substrate side, so that the screen mask can be closely attached to the surface of the substrate. Pressing the electrolyte membrane fills the penetrations in the screen mask with the seepage liquid (plating solution) that seeps out from the electrolyte membrane swollen by the plating solution. The penetrations are shaped according to a predetermined pattern, so that a metal film of a predetermined pattern can be formed on the surface of the substrate by electrolytic plating.

Here, the frame that supports the periphery of the screen mask is supported on the substrate side, so the electrolyte membrane is pressed against the opening edge of the frame by the hydraulic pressure of the plating solution. Even in such a case, an inner covering made of an elastic material softer than the material of the frame is formed along the opening edge of the frame, so that the inner covering can be prevented from elastically deforming and damaging the electrolyte membrane. Furthermore, since the frame is harder than the inner covering, even if the frame is pressed against the electrolyte membrane, the shape of the frame is less likely to deform, and the screen mask can maintain its adhesion to the substrate.

For example, an outer covering portion made of the soft elastic material may be further formed along the outer peripheral edge of the frame body facing the electrolyte membrane.

During film formation, the electrolyte membrane may be pressed toward the outer edge of the frame by the hydraulic pressure of the plating solution. Even in such a case, an outer coating made of an elastic material softer than the material of the frame is formed along the outer edge of the frame facing the electrolyte membrane, so that the outer coating can be prevented from elastically deforming and damaging the electrolyte membrane.

For example, the surface formed between the opening edge and the outer periphery and facing the electrolyte membrane may be coated with the soft elastic material so that the inner coating portion and the outer coating portion are continuous.

In this example, the force with which the electrolyte membrane presses against the frame can be dispersed across the entire soft elastic material. This makes it possible to prevent stress from acting locally on the electrolyte membrane.

For example, the film forming apparatus includes a mounting table on which the substrate is placed. The mounting table is formed with a first recess for accommodating the substrate and a second recess for accommodating the mask structure with the substrate accommodated in the first recess. The mounting table may be formed with an edge covering portion made of the soft elastic material along the opening edge of the second recess.

During film formation, the electrolyte membrane may be pressed against the edge of the opening of the second recess in the mounting table due to the liquid pressure of the plating solution. Even in such a case, the mounting table has an edge covering portion formed along the edge of the opening of the second recess, so that damage to the electrolyte membrane can be prevented.

For example, the screen mask may have a mesh portion with openings formed in a lattice pattern, and a mask portion that is fixed to the mesh portion on the substrate side of the mesh portion and forms the through-holes, and the mask portion may be elastically deformed by pressure from the electrolyte membrane.

In this example, during film formation, the electrolyte membrane presses against the masked portion due to the liquid pressure of the plating solution. This pressure from the electrolyte membrane causes the masked portion to elastically deform, so that the masked portion can maintain its adhesion to the substrate.

According to the present invention, even when a mask structure is used, damage to the electrolyte membrane when pressed can be suppressed.

1 is a schematic cross-sectional view showing an example of a metal film forming apparatus according to an embodiment of the present invention. 2 is a schematic perspective view of a mask structure of the film forming apparatus shown in FIG. 1 and a schematic perspective view of a substrate on which a metal film is formed. FIG. 3 is a partially enlarged cross-sectional view taken along line AA shown in FIG. 2. FIG. 3B is an enlarged cross-sectional view of part C in FIG. 3A. 2 is a schematic cross-sectional view for explaining film formation by the film forming apparatus shown in FIG. 1 . FIG. 5 is a cross-sectional view of a main part of FIG. 4 . FIG. 3C is a cross-sectional view of the portion shown in FIG. 3B during film formation. 4 is a flowchart illustrating an example of a method for forming a metal film using the film forming apparatus according to an embodiment of the present invention. 11 is a partial cross-sectional view of a mask structure of a film forming apparatus according to a first modified example. 11 is a partial cross-sectional view of a mask structure of a film forming apparatus according to a second modified example. FIG. 11 is a partial cross-sectional view of a mask structure of a film forming apparatus according to a third modified example. 13 is a partially enlarged cross-sectional view of a mounting table of a film forming apparatus according to a fourth modified example. FIG.

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

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

The substrate B functions as a cathode. There are no particular limitations on the material of the substrate B, so 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 a 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 made of the metal coating F to be formed on the surface of the insulating substrate.

The anode 11 is, for example, a non-porous (e.g., non-porous) anode made of the same metal as the metal coating. The anode 11 has a block or plate shape. Examples of the material of 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.

The plating solution L is a solution that contains the metal of the metal film 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.

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 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.

The container 15 is made of a material that is insoluble in the plating solution L. The container 15 has a container space 15a for containing the plating solution. 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 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 container space 15a to be sealed by the electrolyte membrane 13.

As shown in Figures 1 and 4, the linear actuator 70 raises and lowers the container 15 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 container 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 is formed with a supply flow path 15b for supplying the plating solution L to the container space 15a. Furthermore, the container 15 is formed with a discharge flow path 15c for discharging 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.

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 plating liquid L. The liquid supply pipe 50 connects the liquid tank 90 to the container 15. The liquid supply pipe 50 is provided with a pump 80. The pump 80 supplies plating liquid L from the liquid tank 90 to the container 15. The liquid discharge pipe 52 connects the liquid tank 90 to the container 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 liquid L in the container space 15a to a predetermined pressure.

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

Furthermore, by continuing to drive the pump 80, the liquid pressure of the plating solution L in the storage space 15a can be maintained at a predetermined pressure by the pressure adjustment 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. Therefore, the pump 80 corresponds to the "pressing mechanism" of the present invention. However, as long as the electrolyte membrane 13 can press the mask structure 60, the pressing mechanism is not particularly limited. Instead of the pump 80, an injection mechanism consisting of a piston and a cylinder that injects the plating solution may be used.

The mounting table 40 is formed of a conductive material (e.g., metal), for example. 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 is a recess that accommodates the mask structure 60 with the substrate B accommodated in the first recess 41.

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

The mask structure 60 includes a frame body 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 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 wires 64b, 64b that intersect with them are arranged at intervals. As a result, a plurality of openings 64c, 64c, ... are formed in a lattice pattern in the mesh portion 64. 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 the material of the wires 64a, 64b include metal materials such as stainless steel, and resin materials such as polyester.

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 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 an acrylic resin, a vinyl acetate resin, a polyvinyl resin, a polyimide resin, or a polyester resin. 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.

The frame body 61 supports the periphery 62a of the screen mask 62 on the substrate B side (mounting table 40 side) relative to the frame body 61. Specifically, the periphery 62a of the screen mask 62 is fixed to the frame body 61. In this embodiment, the screen mask 62 has a rectangular outer shape. Therefore, the frame body 61 has a rectangular frame-like shape. The material of the frame body 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 body 61 can be a metal material such as stainless steel, or a resin material such as thermoplastic resin. The frame body 61 is formed, for example, by punching a metal plate, and has a thickness of about 1 mm to 3 mm. Note that in FIG. 3A and other figures, the thickness of the frame body 61 is drawn thicker than the actual thickness for the sake of convenience of explanation.

A covering portion 66 is formed on the surface of the frame body 61. The covering portion 66 is made of a softer elastic material than the material of the frame body 61. The covering portion 66 includes an inner covering portion 66A, an outer covering portion 66B, and a flat covering portion 66C.

As shown in Figures 3A and 5A, the inner covering portion 66A is formed along the opening edge 61a of the frame body 61 that contacts the electrolyte membrane 13. The inner covering portion 66A covers the opening edge 61a of the frame body 61. Here, the opening edge 61a of the frame body 61 is a ridge (edge portion) formed by the facing surface 61c that faces the electrolyte membrane 13 and the inner peripheral surface 61d that forms the internal space 69 of the frame body 61. The inner covering portion 66A has an extension portion 66D that extends from the opening edge 61a along the inner peripheral surface 61d.

The outer covering portion 66B is formed along the outer peripheral edge 61b of the frame body 61 that faces the electrolyte membrane 13. The outer covering portion 66B covers the outer peripheral edge 61b of the frame body 61. Here, the outer peripheral edge 61b of the frame body 61 is a ridge (edge portion) formed by the facing surface 61c that faces the electrolyte membrane 13 and the outer peripheral surface 61e of the frame body 61. The outer covering portion 66B has an extension portion 66E that extends from the outer peripheral edge 61b along the outer peripheral surface 61e.

The flat covering portion 66C is formed on the surface (opposing surface) 61c between the opening edge 61a and the outer peripheral edge 61b. The flat covering portion 66C covers the opposing surface 61c. The flat covering portion 66C makes the inner covering portion 66A and the outer covering portion 66B into a single continuous portion. In this embodiment, as shown in FIG. 3A, the covering portion 66 is formed in a portion other than the surface to which the peripheral edge 62a of the screen mask 62 is fixed.

The material of the covering portion 66 is made of a softer elastic material than the material of the frame body 61. As long as the material of the covering portion 66 can avoid damage to the electrolyte membrane 13, there is no particular limitation on the material of the covering portion 66. It is preferable that the covering portion 66 undergoes compressive elastic deformation due to pressure from the electrolyte membrane 13. For example, the material of the covering portion 66 can be a rubber material such as silicone rubber (PMDS) or ethylene propylene diene rubber (EPDM). The hardness of the rubber material is preferably HS100 or less, and more preferably HS50 or less, in Shore A hardness. Note that the "soft elastic material" is, for example, a material that has a relatively low hardness measured with a hardness meter of a predetermined standard and a low Young's modulus in a tensile test. The thickness of the covering portion 66 is thinner than the thickness of the frame body 61. Specifically, the thickness of the covering portion 66 is preferably in the range of about 1/5 to 1/10 of the thickness of the frame body 61.

With reference to Figures 4 to 6, a film formation method using the film formation apparatus 1 will be described. First, as shown in Figure 6, the placement step S1 is performed. In this step, the substrate B and the mask structure 60 are placed on the mounting table 40. Specifically, the substrate B is accommodated in the first recess 41 of the mounting table 40, and then the mask structure 60 is accommodated in the second recess 42. At this time, the alignment of the substrate B with respect to the anode 11 attached to the container 15 is adjusted, and the temperature of the substrate B may be adjusted.

Next, the pressing step S2 is performed. In this step, first, the linear actuator 70 is driven to lower the container 15 from the state shown in FIG. 1 to the state shown in FIG. 4 toward the mask structure 60. Next, the pump 80 is driven. This supplies the plating solution L to the container space 15a of the container 15. Since the pressure control valve 54 is provided in the liquid discharge pipe 52, the liquid pressure of the plating solution L in the container space 15a is maintained at a predetermined pressure. As a result, as shown in FIG. 4, the electrolyte membrane 13 is deformed toward the internal space 69 of the frame 61 by the liquid pressure, and the mask structure 60 can be sandwiched between the electrolyte membrane 13 and the substrate B. Furthermore, the electrolyte membrane 13 acting on the liquid pressure of the plating solution L can press the mask structure 60.

As shown in Figures 4 and 5A, the peripheral edge 62a of the screen mask 62 is supported by the frame 61 on the substrate B side, so that the screen mask 62 can 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 undergoes compressive elastic deformation due to the liquid pressure of the plating solution L, improving the adhesion between the mask portion 65 and the substrate B.

Furthermore, when the pressure on the electrolyte membrane 13 is continued, as shown in Figures 5A and 5B, the seepage liquid (plating liquid) La seeping out from the electrolyte membrane 13 swollen by the plating liquid L fills the penetration portion 68 formed in the screen mask 62.

As shown in FIG. 5A, the peripheral edge 62a of the screen mask 62 is supported on the substrate B side relative to the frame 61. This support causes the electrolyte membrane 13 to be pressed against the opening edge 61a of the frame 61 and the outer peripheral edge 61b of the frame 61 when the liquid pressure of the plating solution L acts on the electrolyte membrane 13.

An inner covering portion 66A made of an elastic material softer than the material of the frame body 61 is formed along the opening edge 61a of the frame body 61. Furthermore, an outer covering portion 66B made of an elastic material softer than the material of the frame body 61 is formed along the outer peripheral edge 61b of the frame body 61 facing the electrolyte membrane 13. This allows the inner covering portion 66A to elastically deform and the outer covering portion 66B to elastically deform, preventing damage to the electrolyte membrane 13.

In particular, unlike FIG. 5A, if the opposing surface 61c of the frame body 61 protrudes toward the electrolyte membrane 13 side beyond the opposing surface 40a of the mounting table 40, the electrolyte membrane 13 is likely to be damaged by the outer peripheral edge 61b of the frame body 61. Even if a gap is formed between the side surface 42a of the second recess 42 and the outer peripheral surface 61e of the frame body 61, the electrolyte membrane 13 is likely to be damaged by the outer peripheral edge 61b of the frame body 61.

However, in this embodiment, by providing the outer coating portion 66B on the frame body 61, it is possible to prevent the outer coating portion 66B from elastically deforming and damaging the electrolyte membrane 13. Furthermore, if a gap is formed between the side surface 42a of the second recess 42 and the outer peripheral surface 61e of the frame body 61, the outer coating portion 66B functions as a sealant and can prevent the plating solution L from entering this gap.

The flat covering portion 66C forms a facing surface 61c against the electrolyte membrane so that the inner covering portion 66A and the outer covering portion 66B are continuous, and the facing surface 61c is covered with a soft elastic material. This allows the force of the electrolyte membrane 13 pressing against the frame 61 to be dispersed across the entire soft elastic material. As a result, it is possible to prevent localized stress from acting on the electrolyte membrane 13.

The frame 61 is harder than the inner covering portion 66A. Therefore, even if the frame 61 is pressed against the electrolyte membrane 13, the shape of the frame 61 is not easily deformed, and the screen mask 62 can maintain its adhesion to the substrate B.

Next, the film formation step S3 is performed. In this step, the pressing state by the electrolyte membrane 13 in the pressing step S2 is maintained, and the metal film F is formed. Specifically, a voltage is applied between the anode 11 and the substrate B. As a result, the metal ions contained inside the electrolyte membrane 13 move to the surface of the substrate B via the seepage liquid La, and the metal ions are reduced on the surface of the substrate B. Since the seepage liquid La filled in the through portion 68 is sealed inside the through portion 68 by the electrolyte membrane 13, a metal film F of a predetermined pattern can be formed on the surface of the substrate B (see FIG. 2). Furthermore, since the seepage liquid La is uniformly pressurized by the pressing of the electrolyte membrane 13, a homogeneous metal film F can be formed. When manufacturing wiring using the metal film F, the conductive underlayer formed on the surface of the insulating substrate B may be etched.

<Modification>
7A to 7C are partial cross-sectional views of mask structures of film forming apparatuses according to Modifications 1 to 3. These modifications differ from the embodiment shown in Fig. 3A in the form of a covering portion covering a frame 61 of a mask structure 60. Therefore, only the differences from the above-described embodiment will be described, and detailed descriptions of similar configurations will be omitted.

For example, when the electrolyte membrane 13 does not directly contact the outer peripheral edge 61b of the frame body 61, only the inner covering portion 66A may be formed on the frame body 61 as shown in FIG. 7A. Alternatively, the inner covering portion 66A and the outer covering portion 66B may be formed separately on the frame body 61 as shown in FIG. 7B. According to the modified example 2 of FIG. 7B, in the above-mentioned pressing step S2 and the membrane forming step S3, the inner covering portion 66A and the outer covering portion 66B are elastically deformed independently by pressing the electrolyte membrane 13, and damage to the electrolyte membrane 13 can be avoided.

In FIG. 7C, a covering portion 66 is formed on the entire surface of the frame body 61. That is, in the third modification, a bottom covering portion 66F made of a softer elastic material than the material of the frame body 61 is also formed between the frame body 61 and the peripheral edge 62a of the screen mask 62. Therefore, the bottom covering portion 66F is elastically deformed by the pressure of the electrolyte membrane 13, thereby improving the adhesion between the mask structure 60 and the substrate B.

Figure 8 is a partially enlarged cross-sectional view of the mounting table 40 of the film forming apparatus 1 according to the fourth modification. In the fourth modification, the mounting table 40 has an edge covering portion 48 formed along the opening edge 42b of the second recess 42, the edge covering portion 48 being made of a softer elastic material than the material of the frame 61. As a result, even if the electrolyte membrane 13 is pressed against the opening edge 42b of the second recess 42 by the liquid pressure of the plating solution L during film formation, the edge covering portion 48 is elastically deformed, and damage to the electrolyte membrane 13 can be prevented.

In particular, when the opposing surface 40a of the mounting base 40 protrudes toward the electrolyte membrane 13 more than the opposing surface 61c of the frame body 61, the electrolyte membrane 13 is easily damaged by the opening edge 42b of the second recess 42. Therefore, by providing the edge covering portion 48, damage to the electrolyte membrane 13 can be avoided. Furthermore, in this embodiment, the edge covering portion 48 and the covering portion 66 are made of the same elastic material, so that wear due to contact between the edge covering portion 48 and the outer covering portion 66B can be suppressed.

The present invention is illustrated by the following examples.

[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 embodiment shown in FIG. 1. The mask structure was a stainless steel frame with a silicone rubber coating having a Shore A hardness of HS50. 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 as follows: the temperature of the plating solution was 42° C., the liquid pressure of the plating solution was 1 MPa, the current density was 7 A/dm ² , and the cumulative pressing time was 500 seconds.

[Comparative Example]
A copper film was formed in the same manner as in Example 1. The difference from Example 1 was that the mask structure had no covering portion provided on the stainless steel frame.

The state of the electrolyte membrane in the membrane forming apparatus of the embodiment and the comparative example after membrane formation was confirmed. There was no damage to the electrolyte membrane in the membrane forming apparatus of the embodiment. On the other hand, the electrolyte membrane in the membrane forming apparatus of the comparative example was damaged.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the film forming apparatus according to the above embodiment, but includes all aspects included in the concept of the present invention and the scope of the claims. In addition, each configuration may be appropriately and selectively combined to achieve the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment may be appropriately changed depending on the specific aspect of the present invention.

Reference Signs List 1: film forming apparatus, 13: electrolyte membrane, 40: mounting table, 41: first recess, 42: second recess, 42b: opening edge, 60: mask structure, 61: frame, 62: screen mask, 64: mesh portion, 65: mask portion, 61a: opening edge, 61b: outer periphery, 66A: inner covering portion, 66B: outer covering portion, 68: through portion, B: substrate, F: metal coating, L: plating solution

Claims (5)

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 mask structure is sandwiched between an electrolyte membrane and a substrate, the film formation apparatus comprising:
the film forming apparatus includes a pressing mechanism that presses the mask structure with the electrolyte membrane by a hydraulic pressure of a plating solution,
The mask structure includes:
a screen mask having through-holes formed therein according to the predetermined pattern;
a frame supporting a periphery of the screen mask on the base material side,
In the membrane forming apparatus, an inner covering portion made of an elastic material softer than the material of the frame is formed on the frame along an opening edge that contacts the electrolyte membrane. The film forming device according to claim 1, further comprising an outer coating portion made of the soft elastic material formed along the outer periphery of the frame body facing the electrolyte membrane. The film forming device according to claim 2, wherein the surface formed between the opening edge and the outer periphery and facing the electrolyte membrane is coated with the soft elastic material so that the inner coating portion and the outer coating portion are continuous. A mounting table for mounting the base material is provided,
the mounting table is formed with a first recess for accommodating the base material, and a second recess for accommodating the mask structure with the base material accommodated in the first recess,
The film forming apparatus according to claim 1 , wherein the mounting table has an edge covering portion formed of the soft elastic material along an opening edge of the second recess. The screen mask comprises:
A mesh portion having openings formed in a lattice pattern;
a mask portion fixed to the mesh portion on the base material side of the mesh portion and having the through-portion formed therein;
The film forming apparatus according to claim 1 , wherein the mask portion is elastically deformed by pressure from the electrolyte membrane.

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