Film forming apparatus and film forming method for forming metal film

Abstract

A film forming apparatus includes a masking member. The masking member has a mask portion. The mask portion has formed therein a plurality of penetrating portions that penetrates through the mask portion in accordance with a predetermined pattern to expose the mesh portion and a plurality of recessed grooves provided on a surface opposing an electrolyte membrane of the mask portion so as to be continuous with each of the penetrating portions. The film forming apparatus further includes a suction device that sucks air in the penetrating portions via the plurality of recessed grooves, with the masking member being in contact with a substrate.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese patent application JP 2024-113934 filed on Jul. 17, 2024, the entire content of which is hereby incorporated by reference into this application.BACKGROUNDTechnical Field

[0002] The present disclosure relates to a film forming apparatus and a film forming method for forming a metal film.Background Art

[0003] Conventionally, a film forming apparatus for forming a metal film on a substrate has been known. In a metal film forming apparatus described in JP 2023-139630 A, voltage is applied between an anode and a substrate with an electrolyte membrane pressed against the substrate so as to reduce metal ions contained in the electrolyte membrane so that a metal film is partially formed on a surface of the substrate. Prior to film forming, the electrolyte membrane and the substrate are brought into contact with each other while sucking air between the substrate and the electrolyte membrane using a suction device.SUMMARY

[0004] Here, when a metal film having a predetermined pattern is formed using a masking member in which a penetrating portion having the predetermined pattern is formed in a mask portion, the mask portion as well as an electrolyte membrane deforms due to suction by a sucking device. When the metal film is repeatedly formed, the mark portion repeatedly deforms, which could cause the mask portion to plastically deform. As a result, it is presumed that a metal film having a desired pattern is failed to be formed.

[0005] The present disclosure has been made in view of such an issue, and provides a film forming apparatus and a film forming method for forming a metal film capable of forming a metal film having a desired pattern while suppressing plastic deformation of a mask portion even when film forming is repeated using a masking member.

[0006] In view of the above issue, a film forming apparatus for forming a metal film according to the present disclosure is a film forming apparatus for forming a metal film having a predetermined pattern on a surface of a substrate by electroplating. The film forming apparatus includes: a container having an opening opposing the substrate, the opening covered by an electrolyte membrane with a plating solution contained in the container; a pressure increase mechanism that increases a pressure of the plating solution contained in the container; and a masking member disposed between the electrolyte membrane and the substrate, the masking member being attached to the container. The masking member includes a mesh portion in a sheet form through which the plating solution for the electroplating passes and a mask portion provided on front and back sides of the mesh portion, the mask portion being sandwiched between the electrolyte membrane and the substrate. In the mask portion, a plurality of penetrating portions that penetrates through the mask portion in accordance with the predetermined pattern to expose the mesh portion and a plurality of recessed grooves provided on a surface opposing the electrolyte membrane of the mask portion so as to be continuous with each of the penetrating portions are formed. The film forming apparatus further includes a suction device that sucks air in the penetrating portions via the plurality of recessed grooves, with the masking member being in contact with the substrate.

[0007] According to the present disclosure, air present between the electrolyte membrane and the masking member can be sucked by the suction device, with the masking member being in contact with the substrate. Specifically, at the time of film forming, air in the penetrating portions of the mask portion is removed through the recessed grooves, so that defects in forming the metal film due to the air can be avoided. Next, with the air removed, the pressure increase mechanism increases the pressure of a plating solution contained in the container, so that the substrate can be uniformly pressed with the electrolyte membrane via the mask portion. With the electrolyte membrane pressed, the penetrating portions are filled with the plating solution exuded from the electrolyte membrane, and the metal film can be formed on the surface of the substrate by electroplating. As a result, even when film forming is repeated using the masking member, the metal film having a desired pattern can be formed while suppressing the plastic deformation of the mask portion.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1A is a schematic cross-sectional view showing an example of a film forming apparatus including a masking member according to an embodiment of the present disclosure prior to forming a metal film;

[0009] FIG. 1B is a cross-sectional view explaining a state of the film forming apparatus of FIG. 1A at the time of film forming;

[0010] FIG. 2 is a schematic perspective view of the masking member and a formed substrate;

[0011] FIG. 3A is a partially enlarged cross-sectional view taken along line A-A of FIG. 2;

[0012] FIG. 3B is a partially enlarged cross-sectional view taken along line C-C of FIG. 3A;

[0013] FIG. 3C is a partially enlarged cross-sectional view taken along line B-B of FIG. 2;

[0014] FIG. 4A is a view for explaining a state in which deaeration process is performed in the cross section shown in FIG. 3A; and

[0015] FIG. 4B is a view for explaining a state in which a pressing process and a film forming process are performed in the cross section shown in FIG. 4A.DETAILED DESCRIPTION

[0016] First, with reference to FIG. 1A to FIG. 4B, a film forming apparatus 1 including a masking member 60 according to an embodiment of the present disclosure will be described.

[0017] As shown in FIG. 1A, the film forming apparatus 1 is a film forming apparatus for forming a metal film F having a predetermined pattern P on a substrate B by electroplating. The film forming apparatus 1 forms the metal film with the masking member 60 sandwiched between an electrolyte membrane 13 and the substrate B. The film forming apparatus 1 includes an anode 11, the electrolyte membrane 13, and a power supply 14 for applying voltage between the anode 11 and the substrate B.

[0018] The film forming apparatus 1 includes a container 15 that contains the anode 11 and a plating solution L, a mount base 40 on which the substrate B is disposed, and the masking member 60. At the time of film forming, the masking member 60 attached to the container 15 is disposed on the mount base 40, together with the substrate B. The electrolyte membrane 13 is disposed between the masking member 60 and the anode 11.

[0019] The film forming apparatus 1 includes a linear actuator 70 for raising and lowering the container 15. The linear actuator 70 may be any moving mechanism that moves at least one of the container 15 and the substrate B in such a manner as to allow the masking member 60 and the substrate B to be separated from and connected with each other.

[0020] The substrate B functions as a cathode. The substrate B is a plate-like substrate. In the present embodiment, the substrate B is a rectangular substrate. Of the surfaces of the substrate B, a surface opposing the electrolyte membrane 13 is a film forming surface that functions as the cathode. The present embodiment uses the substrate B having a metal layer formed on a surface of an insulating substrate. The insulating substrate is made of, for example, glass, ceramics, resin, or a composite material thereof, which is electrically insulative. The metal layer may be made of metal, such as aluminum or copper. The present embodiment forms a wiring pattern from the metal film F, and thus uses the substrate B having the metal layer of copper or the like formed on the surface of the insulating substrate of resin or the like. In this case, after forming the metal film F, a metal layer Ba other than a portion where the metal film F is formed is removed by etching or the like. Thus, the pattern (wiring pattern) P from the metal film F can be formed on the surface of the insulating substrate.

[0021] The anode 11 is, as an example, a non-porous anode (for example, having no pores) made of the same metal as that of the metal film. The anode 11 is in a block-like or a flat plate-like shape. Examples of the material of the anode 11 may include copper. The anode 11 dissolves upon application of voltage of the power supply 14. However, when the film is formed only with the metal ions in the plating solution L, the anode 11 is insoluble in the plating solution L. The anode 11 is electrically connected to the positive electrode of the power supply 14.

[0022] The plating solution L is a liquid containing metal in an ion form of the metal film to be formed. Examples of the metal may include copper or nickel. The plating solution L is a solution in which these metals are dissolved (ionized) with acid, such as a nitric acid, a phosphoric acid, or a sulfuric acid.

[0023] The electrolyte membrane 13 is a membrane that can be impregnated with (contain) the metal ions as well as the plating solution L by being brought into contact 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 in the plating solution L to move toward the substrate B when voltage is applied by the power supply 14. Examples of the material of the electrolyte membrane 13 may include resin having an ion-exchange function, such as a fluorine-based resin, for example, Nafion® manufactured by Du Pont Corporation. The film thickness of the electrolyte membrane 13 may be in a range of 20 μm to 200 μm.

[0024] The container 15 is made of material insoluble in the plating solution L. A storing space 15a that stores the plating solution L is formed in the container 15. The anode 11 is disposed in the storing space 15a of the container 15. An opening 15d is formed at a position opposing the substrate B in the storing space 15a. The opening 15d of the container 15 is covered with the electrolyte membrane 13. Specifically, a peripheral edge of the electrolyte membrane 13 is sandwiched between the container 15 and a frame 17. In this manner, the plating solution L within the storing space 15a can be sealed with the electrolyte membrane 13. A deaeration port 17a is formed in the frame 17.

[0025] As shown in FIG. 1A and FIG. 1B, the linear motion actuator 70 raises and lowers the container 15, allowing the substrate B and the masking member 60 to be flexibly separated from and contacted with each other. In the present embodiment, with the mount base 40 securely fixed, the linear motion actuator 70 raises and lowers the container 15. The linear motion actuator 70 is an electric actuator and converts a rotational motion of a motor into a linear motion by means of a ball screw or the like (not shown). However, in place of such an electric actuator, a hydraulic or a pneumatic actuator may be used.

[0026] In the container 15, a supply port 15b for supplying the plating solution L to the storing space 15a is formed. In the container 15, a discharge port 15c for discharging the plating solution L from the storing space 15a is formed. The supply port 15b and the discharge port 15c are holes communicating with the storing space 15a. The supply port 15b and the discharge port 15c are formed across the storing space 15a. The supply port 15b is fluidly connected to a liquid supply pipe 51. The discharge port 15c is fluidly connected to a liquid discharge pipe 52.

[0027] The film forming apparatus 1 further includes a tank 90, the liquid supply pipe 50, the liquid discharge pipe 52, and a pump 80. As shown in FIG. 1A, the tank 90 contains the plating solution L. The liquid supply pipe 50 connects the tank 90 and the container 15. The liquid supply pipe 50 is provided with the pump 80. The pump 80 supplies the plating solution L from the tank 90 to the container 15. The liquid discharge pipe 52 connects the tank 90 and the container 15. The liquid discharge pipe 52 is provided with a pressure regulating valve 54. The pressure regulating valve 54 adjusts the pressure (hydraulic pressure) of the plating solution L in the storing space 15a to a predetermined pressure.

[0028] In the present embodiment, the plating solution L is sucked from the tank 90 into the liquid supply pipe 50 by driving the pump 80. The sucked plating solution L is pumped through the supply port 15b to the storing space 15a. The plating solution L in the storing space 15a is returned to the tank 90 via the discharge port 15c. In this manner, the plating solution L circulates inside the film forming apparatus 1.

[0029] Further, by continuing driving the pump 80, the hydraulic pressure of the plating solution L in the storing space 15a can be maintained at a predetermined pressure by means of the pressure regulating valve 54. The pump 80 is for pressing the masking member 60 by means of the electrolyte membrane 13 on which the hydraulic pressure of the plating solution L is exerted. The pump 80 is a pressure increase mechanism that increases the hydraulic pressure of the plating solution L contained in the container 15.

[0030] The mount base 40 includes a main body 41 made of an insulating material, as an example. The main body 41 has formed therein a projection 43 projecting toward the masking member 60 and the projection 43 has formed therein a recess 44 for accommodating the substrate B.

[0031] As shown in FIG. 1A, the masking member 60 includes a frame 61 and a screen mask 62. The masking member 60 is disposed between the electrolyte membrane 13 and the substrate B and is attached to the container 15. A peripheral edge 62a of the screen mask 62 is securely fixed to the frame 61. Examples of the material of the frame 61 may include a metal material such as stainless steel or a resin material such as a thermoplastic resin.

[0032] As shown in FIG. 2, the screen mask 62 includes a sheet-like mesh portion 64 and a mask portion 65. The screen mask 62 has a flexibility of about 50 μm to 400 μm. The screen mask 62 is supported on the frame 61 on a side facing the electrolyte membrane 13.

[0033] A peripheral edge of the mesh portion 64 is securely fixed to the frame 61 via a part of the mask portion 65. The mesh portion 64 is a portion through which the plating solution for electroplating passes, and has formed therein a plurality of openings 64c, 64c . . . in a grid pattern. Specifically, as shown in FIG. 2 and FIG. 3A, the mesh portion 64 is a mesh-like portion in which a plurality of oriented wires 64a, 64b is woven so as to intersect with each other. The plurality of wires 64a, 64a is arranged at intervals from each other, and the plurality of wires 64b, 64b intersecting with the plurality of wires 64a, 64a is arranged at intervals from each other. As a result, the plurality of openings 64c, 64c . . . is formed in a grid pattern in the mesh portion 64. The material of the wires 64a, 64b is not particularly limited as long as the wires have corrosion resistance against the plating solution L. Examples of the material of the wires 64a, 64b may include a resin material, such as polyester.

[0034] The mask portion 65 is securely fixed to the mesh portion 64. Penetrating portions 68 corresponding to a predetermined pattern P are formed in the mask portion 65. The penetrating portions 68 penetrate the mask portion 65 in accordance with the predetermined pattern P to expose the mesh portion 64. The mask portion 65 is a portion that tightly adheres to the substrate B at the time of film forming by being pressed with the electrolyte membrane 13. The material of the mask portion 65 is not particularly limited as long as it can tightly adhere to the substrate B. Examples of the material of the mask portion 65 may include a rubber material, such as silicone rubber (PMDS) or ethylene propylene diene rubber (EPDM). The hardness of the rubber material may be equal to or smaller than HS100, or equal to or smaller than HS50 in Shore A hardness.

[0035] The mask portion 65 is made of an elastic material that is compressively elastically deformed by being pressed with the electrolyte membrane 13. In order to secure the adhesion to the substrate B, the deformation amount in the thickness direction (pressing direction) of the mask portion 65 due to the pressing by means of the electrolyte membrane 13 may be in a range of 5 to 20% of the thickness of the mask portion before deformation. The screen mask 62 having the predetermined pattern P can be manufactured by a typical silk screen manufacturing technique using an emulsion. As shown in FIGS. 3A, 3B, and 4A, the mask portion 65 is provided on the front and back sides of the mesh portion 64 and is sandwiched between the electrolyte membrane 13 and the substrate B. In the mask portion 65, a first elastic layer 65a is formed on a side closer to the electrolyte membrane 13 relative to the mesh portion 64 and a second elastic layer 65b is formed on a side closer to the substrate B relative to the mesh portion 64. The first elastic layer 65a and the second elastic layer 65b are jointed together by impregnating the mesh portion 64 with the material of the mask portion 65.

[0036] Further, as shown in FIG. 2, in the mask portion 65, a plurality of recessed grooves 67 provided on a surface opposing the electrolyte membrane 13 of the mask portion 65 is formed so as to be continuous with each of the penetrating portions 68. As shown in FIG. 1B, the film forming apparatus 1 further includes a suction device 81 that sucks air in the penetrating portions 68 via the plurality of recessed grooves 67 shown in FIG. 2, with the masking member 60 (screen mask 62 thereof) being in contact with the substrate B. In the present embodiment, the suction device 81 is connected to the deaeration port 17a of the frame 17. Thus, air in the recessed grooves 67 can be removed prior to film forming. Examples of the suction device 81 may include a suction pump.

[0037] As shown in FIG. 2, the plurality of recessed grooves 67 is formed in the first elastic layer 65a. In the present embodiment, each recessed groove 67 is a linear groove having a rectangular groove cross-section, but is not limited thereto. In the present embodiment, a groove bottom surface 67t of the recessed groove 67 is a surface derived from the shape of the wires 64a, 64b constituting the mesh portion 64. On the groove bottom surface 67t, the wires 64a, 64b may be partially exposed or the groove bottom surface 67t may be covered with the material of the mask portion 65 as long as the shape with projections and recesses derived from the shape of the wires 64a, 64b is formed on the groove bottom surface 67t. Thus, even when the electrolyte membrane 13 is deformed so as to close the recessed grooves 67 during air removing by means of the suction device 81, small gaps due to the aforementioned projections and recesses are formed between the groove bottom surface 67t and the electrolyte membrane 13. Therefore, the air can be made to pass through the recessed grooves 67. The groove width of the recessed groove 67 may be from 50 μm to 300 μm. The groove width of the recessed groove 67 may be smaller than the film thickness of the electrolyte membrane 13. In this manner, even when the electrolyte membrane 13 is deformed, the recessed grooves 67 can be prevented from being closed by the electrolyte membrane 13.

[0038] The plurality of recessed grooves 67 includes a first recessed groove 67a and a second recessed groove 67b. As shown in FIG. 2 and FIG. 3A, the present embodiment includes a plurality of first recessed grooves 67a provided on the surface opposing the electrolyte membrane 13 of the mask portion 65 so as to connect the penetrating portions 68, 68 that are adjacent to each other. The present embodiment also includes a plurality of second recessed grooves 67b provided on the surface opposing the electrolyte membrane 13 of the mask portion 65 so as to connect the penetrating portions 68 and the frame 61. With the masking member 60 being in contact with the substrate B, the air present between the electrolyte membrane 13 and the masking member 60 can be removed via the first recessed grooves 67a and the second recessed grooves 67b by means of the suction device 81.

[0039] Further, in the present embodiment, a plurality of intersecting grooves 67d intersecting the second recessed grooves 67b is formed in the mask portion 65. This can improve the permeability of air to the second recessed grooves 67b during the air removing. The intersecting grooves 67d are connected to a third recessed groove 67c described later, with the opposite ends of each intersecting groove 67d connected to the third recessed groove 67c.

[0040] As shown in FIG. 2 and FIG. 3C, the frame 61 has formed therein the third recessed groove 67c connected to all the second recessed grooves 67b and intersecting grooves 67d. The third recessed groove 67c encircles the frame 61. The frame 61 has formed therein a connecting groove 67e connected to the third recessed groove 67c and communicating with the aforementioned deaeration port 17a. The suction device 81 sucks air in the penetrating portions 68 through the third recessed groove 67c via the air deaeration port 17a and the connecting groove 67e. In sucking by the suction device 81, the air is uniformly sucked from around the pattern P formed by the plurality of penetrating portions 68, so that the air removing performance of the penetrating portions 68 can be improved.

[0041] With reference to FIGS. 1A, 1B, 4A, and 4B, a film forming method using the film forming apparatus 1 will be described. First, as shown in FIG. 1A, the substrate B is disposed on the mount base 40. In the present embodiment, the metal layer Ba of the substrate B projects from the mount base 40 in a state in which the substrate B is accommodated in the recess 44. Thus, the mask portion 65 of the masking member 60 can be uniformly brought into contact with the surface of the substrate B.

[0042] Next, as shown in FIG. 1B, the linear actuator 70 is driven to lower the container 15 toward the substrate B. Since the masking member 60 is integrally attached to the container 15 at a position opposing the electrolyte membrane 13, the surface of the substrate B can be covered with the mask portion 65 of the masking member 60 by lowering the container 15.

[0043] Next, as shown in FIG. 4A, with the masking member 60 being in contact with the substrate B, air A in the plurality of penetrating portions 68 is removed via the plurality of recessed grooves 67 by means of the suction device 81. The air present in the penetrating portions 68 passes through the first recessed grooves 67a, the second recessed grooves 67b, and the like through sucking by the suction device 81 and is discharged through the third recessed groove 67c of the frame 61. The inside of the penetrating portions 68 is a sealed space, the pressure of which turns into negative, and thus, the second elastic layer 65b of the mask portion 65 is elastically deformed, allowing the mask portion 65 to tightly adhere to the substrate B.

[0044] Next, with the air removed, the pump 80 is driven to increase the pressure of the plating solution L contained in the container 15, thereby pressing the substrate B with the electrolyte membrane 13 via the mask portion 65. Specifically, the plating solution L is supplied to the storing space 15a of the container 15. Since the pressure regulating valve 54 is provided in the liquid discharge pipe 52, the hydraulic pressure of the plating solution L in the storing space 15a is maintained at a predetermined pressure. Such pressing can improve the adhesion of the screen mask 62 to the substrate B. Since the mask portion 65 is made of an elastic material, the mask portion 65 is compressively deformed with the hydraulic pressure of the plating solution L so as to improve the adhesion between the mask portion 65 and the substrate B. Since the mask portion 65 is securely fixed to the mesh portion 64, the mask portion 65 can be uniformly pressed via the mesh portion 64 as shown in FIG. 4B. When the pressing with the electrolyte membrane 13 is continued, the penetrating portions 68 formed in the screen mask 62 are filled with an exuded solution La (plating solution L) exuded from the electrolyte membrane 13 swollen with the plating solution L. Note that since the air is removed, almost no air is present in the penetrating portions 68.

[0045] Next, while the state of being pressed with the electrolyte membrane 13 is maintained, the metal film F is formed by electroplating. Specifically, voltage is applied between the anode 11 and the substrate B. In this manner, the metal ions contained in the plating solution L pass through the electrolyte membrane 13. The metal ions that have passed through the electrolyte membrane 13 move via the exuded solution La to the surface of the substrate B to be reduced on the surface of the substrate B. As a result, as shown in FIG. 2, the metal film F corresponding to the penetrating portions 68 formed on the mask portion 65 can be stably formed on the surface of the substrate B.

[0046] Furthermore, since the exuded solution La is uniformly pressurized due to the pressing with the electrolyte membrane 13, the homogeneous metal film F can be formed. Thereafter, the linear actuator 70 raises the container 15 to disengage the substrate B from the electrolyte membrane 13, and removes the substrate B from the mount base 40. Note that when wiring is manufactured from the metal film F, the metal layer Ba formed on the surface of an insulating substrate Bb of the substrate B may be etched while maintaining a portion where the metal film F is formed.

[0047] According to the present embodiment, with the mask portion 65 of the masking member 60 being in contact with the substrate B, the air in the penetrating portions 68 can be sucked via the plurality of recessed grooves 67 by means of the suction device 81. Therefore, the air between the substrate B and the masking member does not need to be sucked before bringing the masking member into contact with the substrate B. Thus, even when gas generated during the electroplating accumulates within the plating solution L in the storing space 15a, the mask portion 65 of the masking member 60 is in contact with the substrate B at the time of film forming, and therefore, deformation of the mask portion 65 of the masking member 60 due to the pressure difference from the gas inside the storing space 15a can be suppressed. As a result, even when the film forming is repeatedly performed using the masking member 60, plastic deformation of the screen mask 62 of the masking member 60 can be suppressed.

[0048] Further, when the linear actuator 70 raises the container 15 to disengage the substrate B from the electrolyte membrane 13, the own weight of the plating solution L can be supported by the masking member 60 via the electrolyte membrane 13. Thus, the plastic deformation of the electrolyte membrane 13 can be suppressed due to the own weight of the plating solution L.EXAMPLE

[0049] A mask portion was formed on front and back sides of an LCP resin mesh portion having a wire diameter of 20 μm and 420 mesh, using silicone rubber, and as shown in FIG. 2, a masking member was produced by forming penetrating portions and recessed grooves each having a groove width of 100 μm in the mask portion. Note that the thickness of the mask portion was 20 μm for a portion disposed between an electrolyte membrane and the mesh portion and 30 μm for a portion disposed between the mesh portion and a substrate.

[0050] Next, a copper (Cu) substrate in a square having a thickness of 0.9 mm and one side length of 7.8 cm was prepared. The substrate was subjected to cathode electrolytic degreasing at 55° C. for 1 minute using an IC-200RM manufactured by JCU Corporation, and was then washed with pure water for 1 minute. Further, the substrate was immersed in a 10% dilute sulfuric acid at room temperature for 1 minute to be subjected to acid cleaning, and was then washed with pure water for 1 minute.

[0051] Thereafter, a metal film having a thickness of 5 μm was formed on the surface of the substrate by solid electro deposition (SED) using an apparatus having the same configuration as that of the film forming apparatus for forming a metal film described in the aforementioned embodiment. The film forming conditions were: film forming temperature: 42° C., plating solution: 1 mol / L copper sulfate+0.2 mol / L sulfuric acid, anode: phosphorus-containing copper plate, inter-electrode distance of anode-cathode: 2 mm, pressurization: 0.6 MPa, film forming arca: 38 cm2 / substrate size 61.4 cm2, and current: 7 ASD.

[0052] As Comparative Example 1, only the first recessed grooves were provided in the mask portion of the masking member, and after sucking the air between the substrate B and the masking member before bringing the masking member into contact with the substrate, a metal film that is the same as Example was formed. As Comparative Example 2, after sucking the air between the substrate B and the masking member without providing the recessed grooves in the masking member, a metal film that is the same as Example was formed. As Comparative Example 3, neither providing the recessed grooves in the mask portion of the masking member nor sucking the air between the substrate B and the masking member, a metal film that is the same as Example was formed.

[0053] Film forming of the metal film according to Example and Comparative Examples 1 to 3 was conducted 20 times and the number of defects of the metal film and the degree of deformation of the masking sheet of the masking member were observed. The results regarding the number of defects show that Example and Comparative Example 1 had one, Comparative Example 2 had two, and Comparative Example 3 had 32. Further, plastic deformation of the masking sheet of Example was insignificant as compared to Comparative Examples 1 to 3.

[0054] The embodiment of the present disclosure has been described in detail above, but the present disclosure is not limited to the aforementioned embodiment, and various design changes can be made within the scope without departing from the spirit of the present disclosure described in the scope of the claims.

Examples

example

[0049]A mask portion was formed on front and back sides of an LCP resin mesh portion having a wire diameter of 20 μm and 420 mesh, using silicone rubber, and as shown in FIG. 2, a masking member was produced by forming penetrating portions and recessed grooves each having a groove width of 100 μm in the mask portion. Note that the thickness of the mask portion was 20 μm for a portion disposed between an electrolyte membrane and the mesh portion and 30 μm for a portion disposed between the mesh portion and a substrate.

[0050]Next, a copper (Cu) substrate in a square having a thickness of 0.9 mm and one side length of 7.8 cm was prepared. The substrate was subjected to cathode electrolytic degreasing at 55° C. for 1 minute using an IC-200RM manufactured by JCU Corporation, and was then washed with pure water for 1 minute. Further, the substrate was immersed in a 10% dilute sulfuric acid at room temperature for 1 minute to be subjected to acid cleaning, and was then washed with pure wat...

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese patent application JP 2024-113934 filed on Jul. 17, 2024, the entire content of which is hereby incorporated by reference into this application.BACKGROUNDTechnical Field

[0002] The present disclosure relates to a film forming apparatus and a film forming method for forming a metal film.Background Art

[0003] Conventionally, a film forming apparatus for forming a metal film on a substrate has been known. In a metal film forming apparatus described in JP 2023-139630 A, voltage is applied between an anode and a substrate with an electrolyte membrane pressed against the substrate so as to reduce metal ions contained in the electrolyte membrane so that a metal film is partially formed on a surface of the substrate. Prior to film forming, the electrolyte membrane and the substrate are brought into contact with each other while sucking air between the substrate and the electrolyte membrane using a suction device.SUMMARY

[0004] Here, when a metal film having a predetermined pattern is formed using a masking member in which a penetrating portion having the predetermined pattern is formed in a mask portion, the mask portion as well as an electrolyte membrane deforms due to suction by a sucking device. When the metal film is repeatedly formed, the mark portion repeatedly deforms, which could cause the mask portion to plastically deform. As a result, it is presumed that a metal film having a desired pattern is failed to be formed.

[0005] The present disclosure has been made in view of such an issue, and provides a film forming apparatus and a film forming method for forming a metal film capable of forming a metal film having a desired pattern while suppressing plastic deformation of a mask portion even when film forming is repeated using a masking member.

[0006] In view of the above issue, a film forming apparatus for forming a metal film according to the present disclosure is a film forming apparatus for forming a metal film having a predetermined pattern on a surface of a substrate by electroplating. The film forming apparatus includes: a container having an opening opposing the substrate, the opening covered by an electrolyte membrane with a plating solution contained in the container; a pressure increase mechanism that increases a pressure of the plating solution contained in the container; and a masking member disposed between the electrolyte membrane and the substrate, the masking member being attached to the container. The masking member includes a mesh portion in a sheet form through which the plating solution for the electroplating passes and a mask portion provided on front and back sides of the mesh portion, the mask portion being sandwiched between the electrolyte membrane and the substrate. In the mask portion, a plurality of penetrating portions that penetrates through the mask portion in accordance with the predetermined pattern to expose the mesh portion and a plurality of recessed grooves provided on a surface opposing the electrolyte membrane of the mask portion so as to be continuous with each of the penetrating portions are formed. The film forming apparatus further includes a suction device that sucks air in the penetrating portions via the plurality of recessed grooves, with the masking member being in contact with the substrate.

[0007] According to the present disclosure, air present between the electrolyte membrane and the masking member can be sucked by the suction device, with the masking member being in contact with the substrate. Specifically, at the time of film forming, air in the penetrating portions of the mask portion is removed through the recessed grooves, so that defects in forming the metal film due to the air can be avoided. Next, with the air removed, the pressure increase mechanism increases the pressure of a plating solution contained in the container, so that the substrate can be uniformly pressed with the electrolyte membrane via the mask portion. With the electrolyte membrane pressed, the penetrating portions are filled with the plating solution exuded from the electrolyte membrane, and the metal film can be formed on the surface of the substrate by electroplating. As a result, even when film forming is repeated using the masking member, the metal film having a desired pattern can be formed while suppressing the plastic deformation of the mask portion.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1A is a schematic cross-sectional view showing an example of a film forming apparatus including a masking member according to an embodiment of the present disclosure prior to forming a metal film;

[0009] FIG. 1B is a cross-sectional view explaining a state of the film forming apparatus of FIG. 1A at the time of film forming;

[0010] FIG. 2 is a schematic perspective view of the masking member and a formed substrate;

[0011] FIG. 3A is a partially enlarged cross-sectional view taken along line A-A of FIG. 2;

[0012] FIG. 3B is a partially enlarged cross-sectional view taken along line C-C of FIG. 3A;

[0013] FIG. 3C is a partially enlarged cross-sectional view taken along line B-B of FIG. 2;

[0014] FIG. 4A is a view for explaining a state in which deaeration process is performed in the cross section shown in FIG. 3A; and

[0015] FIG. 4B is a view for explaining a state in which a pressing process and a film forming process are performed in the cross section shown in FIG. 4A.DETAILED DESCRIPTION

[0016] First, with reference to FIG. 1A to FIG. 4B, a film forming apparatus 1 including a masking member 60 according to an embodiment of the present disclosure will be described.

[0017] As shown in FIG. 1A, the film forming apparatus 1 is a film forming apparatus for forming a metal film F having a predetermined pattern P on a substrate B by electroplating. The film forming apparatus 1 forms the metal film with the masking member 60 sandwiched between an electrolyte membrane 13 and the substrate B. The film forming apparatus 1 includes an anode 11, the electrolyte membrane 13, and a power supply 14 for applying voltage between the anode 11 and the substrate B.

[0018] The film forming apparatus 1 includes a container 15 that contains the anode 11 and a plating solution L, a mount base 40 on which the substrate B is disposed, and the masking member 60. At the time of film forming, the masking member 60 attached to the container 15 is disposed on the mount base 40, together with the substrate B. The electrolyte membrane 13 is disposed between the masking member 60 and the anode 11.

[0019] The film forming apparatus 1 includes a linear actuator 70 for raising and lowering the container 15. The linear actuator 70 may be any moving mechanism that moves at least one of the container 15 and the substrate B in such a manner as to allow the masking member 60 and the substrate B to be separated from and connected with each other.

[0020] The substrate B functions as a cathode. The substrate B is a plate-like substrate. In the present embodiment, the substrate B is a rectangular substrate. Of the surfaces of the substrate B, a surface opposing the electrolyte membrane 13 is a film forming surface that functions as the cathode. The present embodiment uses the substrate B having a metal layer formed on a surface of an insulating substrate. The insulating substrate is made of, for example, glass, ceramics, resin, or a composite material thereof, which is electrically insulative. The metal layer may be made of metal, such as aluminum or copper. The present embodiment forms a wiring pattern from the metal film F, and thus uses the substrate B having the metal layer of copper or the like formed on the surface of the insulating substrate of resin or the like. In this case, after forming the metal film F, a metal layer Ba other than a portion where the metal film F is formed is removed by etching or the like. Thus, the pattern (wiring pattern) P from the metal film F can be formed on the surface of the insulating substrate.

[0021] The anode 11 is, as an example, a non-porous anode (for example, having no pores) made of the same metal as that of the metal film. The anode 11 is in a block-like or a flat plate-like shape. Examples of the material of the anode 11 may include copper. The anode 11 dissolves upon application of voltage of the power supply 14. However, when the film is formed only with the metal ions in the plating solution L, the anode 11 is insoluble in the plating solution L. The anode 11 is electrically connected to the positive electrode of the power supply 14.

[0022] The plating solution L is a liquid containing metal in an ion form of the metal film to be formed. Examples of the metal may include copper or nickel. The plating solution L is a solution in which these metals are dissolved (ionized) with acid, such as a nitric acid, a phosphoric acid, or a sulfuric acid.

[0023] The electrolyte membrane 13 is a membrane that can be impregnated with (contain) the metal ions as well as the plating solution L by being brought into contact 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 in the plating solution L to move toward the substrate B when voltage is applied by the power supply 14. Examples of the material of the electrolyte membrane 13 may include resin having an ion-exchange function, such as a fluorine-based resin, for example, Nafion® manufactured by Du Pont Corporation. The film thickness of the electrolyte membrane 13 may be in a range of 20 μm to 200 μm.

[0024] The container 15 is made of material insoluble in the plating solution L. A storing space 15a that stores the plating solution L is formed in the container 15. The anode 11 is disposed in the storing space 15a of the container 15. An opening 15d is formed at a position opposing the substrate B in the storing space 15a. The opening 15d of the container 15 is covered with the electrolyte membrane 13. Specifically, a peripheral edge of the electrolyte membrane 13 is sandwiched between the container 15 and a frame 17. In this manner, the plating solution L within the storing space 15a can be sealed with the electrolyte membrane 13. A deaeration port 17a is formed in the frame 17.

[0025] As shown in FIG. 1A and FIG. 1B, the linear motion actuator 70 raises and lowers the container 15, allowing the substrate B and the masking member 60 to be flexibly separated from and contacted with each other. In the present embodiment, with the mount base 40 securely fixed, the linear motion actuator 70 raises and lowers the container 15. The linear motion actuator 70 is an electric actuator and converts a rotational motion of a motor into a linear motion by means of a ball screw or the like (not shown). However, in place of such an electric actuator, a hydraulic or a pneumatic actuator may be used.

[0026] In the container 15, a supply port 15b for supplying the plating solution L to the storing space 15a is formed. In the container 15, a discharge port 15c for discharging the plating solution L from the storing space 15a is formed. The supply port 15b and the discharge port 15c are holes communicating with the storing space 15a. The supply port 15b and the discharge port 15c are formed across the storing space 15a. The supply port 15b is fluidly connected to a liquid supply pipe 51. The discharge port 15c is fluidly connected to a liquid discharge pipe 52.

[0027] The film forming apparatus 1 further includes a tank 90, the liquid supply pipe 50, the liquid discharge pipe 52, and a pump 80. As shown in FIG. 1A, the tank 90 contains the plating solution L. The liquid supply pipe 50 connects the tank 90 and the container 15. The liquid supply pipe 50 is provided with the pump 80. The pump 80 supplies the plating solution L from the tank 90 to the container 15. The liquid discharge pipe 52 connects the tank 90 and the container 15. The liquid discharge pipe 52 is provided with a pressure regulating valve 54. The pressure regulating valve 54 adjusts the pressure (hydraulic pressure) of the plating solution L in the storing space 15a to a predetermined pressure.

[0028] In the present embodiment, the plating solution L is sucked from the tank 90 into the liquid supply pipe 50 by driving the pump 80. The sucked plating solution L is pumped through the supply port 15b to the storing space 15a. The plating solution L in the storing space 15a is returned to the tank 90 via the discharge port 15c. In this manner, the plating solution L circulates inside the film forming apparatus 1.

[0029] Further, by continuing driving the pump 80, the hydraulic pressure of the plating solution L in the storing space 15a can be maintained at a predetermined pressure by means of the pressure regulating valve 54. The pump 80 is for pressing the masking member 60 by means of the electrolyte membrane 13 on which the hydraulic pressure of the plating solution L is exerted. The pump 80 is a pressure increase mechanism that increases the hydraulic pressure of the plating solution L contained in the container 15.

[0030] The mount base 40 includes a main body 41 made of an insulating material, as an example. The main body 41 has formed therein a projection 43 projecting toward the masking member 60 and the projection 43 has formed therein a recess 44 for accommodating the substrate B.

[0031] As shown in FIG. 1A, the masking member 60 includes a frame 61 and a screen mask 62. The masking member 60 is disposed between the electrolyte membrane 13 and the substrate B and is attached to the container 15. A peripheral edge 62a of the screen mask 62 is securely fixed to the frame 61. Examples of the material of the frame 61 may include a metal material such as stainless steel or a resin material such as a thermoplastic resin.

[0032] As shown in FIG. 2, the screen mask 62 includes a sheet-like mesh portion 64 and a mask portion 65. The screen mask 62 has a flexibility of about 50 μm to 400 μm. The screen mask 62 is supported on the frame 61 on a side facing the electrolyte membrane 13.

[0033] A peripheral edge of the mesh portion 64 is securely fixed to the frame 61 via a part of the mask portion 65. The mesh portion 64 is a portion through which the plating solution for electroplating passes, and has formed therein a plurality of openings 64c, 64c . . . in a grid pattern. Specifically, as shown in FIG. 2 and FIG. 3A, the mesh portion 64 is a mesh-like portion in which a plurality of oriented wires 64a, 64b is woven so as to intersect with each other. The plurality of wires 64a, 64a is arranged at intervals from each other, and the plurality of wires 64b, 64b intersecting with the plurality of wires 64a, 64a is arranged at intervals from each other. As a result, the plurality of openings 64c, 64c . . . is formed in a grid pattern in the mesh portion 64. The material of the wires 64a, 64b is not particularly limited as long as the wires have corrosion resistance against the plating solution L. Examples of the material of the wires 64a, 64b may include a resin material, such as polyester.

[0034] The mask portion 65 is securely fixed to the mesh portion 64. Penetrating portions 68 corresponding to a predetermined pattern P are formed in the mask portion 65. The penetrating portions 68 penetrate the mask portion 65 in accordance with the predetermined pattern P to expose the mesh portion 64. The mask portion 65 is a portion that tightly adheres to the substrate B at the time of film forming by being pressed with the electrolyte membrane 13. The material of the mask portion 65 is not particularly limited as long as it can tightly adhere to the substrate B. Examples of the material of the mask portion 65 may include a rubber material, such as silicone rubber (PMDS) or ethylene propylene diene rubber (EPDM). The hardness of the rubber material may be equal to or smaller than HS100, or equal to or smaller than HS50 in Shore A hardness.

[0035] The mask portion 65 is made of an elastic material that is compressively elastically deformed by being pressed with the electrolyte membrane 13. In order to secure the adhesion to the substrate B, the deformation amount in the thickness direction (pressing direction) of the mask portion 65 due to the pressing by means of the electrolyte membrane 13 may be in a range of 5 to 20% of the thickness of the mask portion before deformation. The screen mask 62 having the predetermined pattern P can be manufactured by a typical silk screen manufacturing technique using an emulsion. As shown in FIGS. 3A, 3B, and 4A, the mask portion 65 is provided on the front and back sides of the mesh portion 64 and is sandwiched between the electrolyte membrane 13 and the substrate B. In the mask portion 65, a first elastic layer 65a is formed on a side closer to the electrolyte membrane 13 relative to the mesh portion 64 and a second elastic layer 65b is formed on a side closer to the substrate B relative to the mesh portion 64. The first elastic layer 65a and the second elastic layer 65b are jointed together by impregnating the mesh portion 64 with the material of the mask portion 65.

[0036] Further, as shown in FIG. 2, in the mask portion 65, a plurality of recessed grooves 67 provided on a surface opposing the electrolyte membrane 13 of the mask portion 65 is formed so as to be continuous with each of the penetrating portions 68. As shown in FIG. 1B, the film forming apparatus 1 further includes a suction device 81 that sucks air in the penetrating portions 68 via the plurality of recessed grooves 67 shown in FIG. 2, with the masking member 60 (screen mask 62 thereof) being in contact with the substrate B. In the present embodiment, the suction device 81 is connected to the deaeration port 17a of the frame 17. Thus, air in the recessed grooves 67 can be removed prior to film forming. Examples of the suction device 81 may include a suction pump.

[0037] As shown in FIG. 2, the plurality of recessed grooves 67 is formed in the first elastic layer 65a. In the present embodiment, each recessed groove 67 is a linear groove having a rectangular groove cross-section, but is not limited thereto. In the present embodiment, a groove bottom surface 67t of the recessed groove 67 is a surface derived from the shape of the wires 64a, 64b constituting the mesh portion 64. On the groove bottom surface 67t, the wires 64a, 64b may be partially exposed or the groove bottom surface 67t may be covered with the material of the mask portion 65 as long as the shape with projections and recesses derived from the shape of the wires 64a, 64b is formed on the groove bottom surface 67t. Thus, even when the electrolyte membrane 13 is deformed so as to close the recessed grooves 67 during air removing by means of the suction device 81, small gaps due to the aforementioned projections and recesses are formed between the groove bottom surface 67t and the electrolyte membrane 13. Therefore, the air can be made to pass through the recessed grooves 67. The groove width of the recessed groove 67 may be from 50 μm to 300 μm. The groove width of the recessed groove 67 may be smaller than the film thickness of the electrolyte membrane 13. In this manner, even when the electrolyte membrane 13 is deformed, the recessed grooves 67 can be prevented from being closed by the electrolyte membrane 13.

[0038] The plurality of recessed grooves 67 includes a first recessed groove 67a and a second recessed groove 67b. As shown in FIG. 2 and FIG. 3A, the present embodiment includes a plurality of first recessed grooves 67a provided on the surface opposing the electrolyte membrane 13 of the mask portion 65 so as to connect the penetrating portions 68, 68 that are adjacent to each other. The present embodiment also includes a plurality of second recessed grooves 67b provided on the surface opposing the electrolyte membrane 13 of the mask portion 65 so as to connect the penetrating portions 68 and the frame 61. With the masking member 60 being in contact with the substrate B, the air present between the electrolyte membrane 13 and the masking member 60 can be removed via the first recessed grooves 67a and the second recessed grooves 67b by means of the suction device 81.

[0039] Further, in the present embodiment, a plurality of intersecting grooves 67d intersecting the second recessed grooves 67b is formed in the mask portion 65. This can improve the permeability of air to the second recessed grooves 67b during the air removing. The intersecting grooves 67d are connected to a third recessed groove 67c described later, with the opposite ends of each intersecting groove 67d connected to the third recessed groove 67c.

[0040] As shown in FIG. 2 and FIG. 3C, the frame 61 has formed therein the third recessed groove 67c connected to all the second recessed grooves 67b and intersecting grooves 67d. The third recessed groove 67c encircles the frame 61. The frame 61 has formed therein a connecting groove 67e connected to the third recessed groove 67c and communicating with the aforementioned deaeration port 17a. The suction device 81 sucks air in the penetrating portions 68 through the third recessed groove 67c via the air deaeration port 17a and the connecting groove 67e. In sucking by the suction device 81, the air is uniformly sucked from around the pattern P formed by the plurality of penetrating portions 68, so that the air removing performance of the penetrating portions 68 can be improved.

[0041] With reference to FIGS. 1A, 1B, 4A, and 4B, a film forming method using the film forming apparatus 1 will be described. First, as shown in FIG. 1A, the substrate B is disposed on the mount base 40. In the present embodiment, the metal layer Ba of the substrate B projects from the mount base 40 in a state in which the substrate B is accommodated in the recess 44. Thus, the mask portion 65 of the masking member 60 can be uniformly brought into contact with the surface of the substrate B.

[0042] Next, as shown in FIG. 1B, the linear actuator 70 is driven to lower the container 15 toward the substrate B. Since the masking member 60 is integrally attached to the container 15 at a position opposing the electrolyte membrane 13, the surface of the substrate B can be covered with the mask portion 65 of the masking member 60 by lowering the container 15.

[0043] Next, as shown in FIG. 4A, with the masking member 60 being in contact with the substrate B, air A in the plurality of penetrating portions 68 is removed via the plurality of recessed grooves 67 by means of the suction device 81. The air present in the penetrating portions 68 passes through the first recessed grooves 67a, the second recessed grooves 67b, and the like through sucking by the suction device 81 and is discharged through the third recessed groove 67c of the frame 61. The inside of the penetrating portions 68 is a sealed space, the pressure of which turns into negative, and thus, the second elastic layer 65b of the mask portion 65 is elastically deformed, allowing the mask portion 65 to tightly adhere to the substrate B.

[0044] Next, with the air removed, the pump 80 is driven to increase the pressure of the plating solution L contained in the container 15, thereby pressing the substrate B with the electrolyte membrane 13 via the mask portion 65. Specifically, the plating solution L is supplied to the storing space 15a of the container 15. Since the pressure regulating valve 54 is provided in the liquid discharge pipe 52, the hydraulic pressure of the plating solution L in the storing space 15a is maintained at a predetermined pressure. Such pressing can improve the adhesion of the screen mask 62 to the substrate B. Since the mask portion 65 is made of an elastic material, the mask portion 65 is compressively deformed with the hydraulic pressure of the plating solution L so as to improve the adhesion between the mask portion 65 and the substrate B. Since the mask portion 65 is securely fixed to the mesh portion 64, the mask portion 65 can be uniformly pressed via the mesh portion 64 as shown in FIG. 4B. When the pressing with the electrolyte membrane 13 is continued, the penetrating portions 68 formed in the screen mask 62 are filled with an exuded solution La (plating solution L) exuded from the electrolyte membrane 13 swollen with the plating solution L. Note that since the air is removed, almost no air is present in the penetrating portions 68.

[0045] Next, while the state of being pressed with the electrolyte membrane 13 is maintained, the metal film F is formed by electroplating. Specifically, voltage is applied between the anode 11 and the substrate B. In this manner, the metal ions contained in the plating solution L pass through the electrolyte membrane 13. The metal ions that have passed through the electrolyte membrane 13 move via the exuded solution La to the surface of the substrate B to be reduced on the surface of the substrate B. As a result, as shown in FIG. 2, the metal film F corresponding to the penetrating portions 68 formed on the mask portion 65 can be stably formed on the surface of the substrate B.

[0046] Furthermore, since the exuded solution La is uniformly pressurized due to the pressing with the electrolyte membrane 13, the homogeneous metal film F can be formed. Thereafter, the linear actuator 70 raises the container 15 to disengage the substrate B from the electrolyte membrane 13, and removes the substrate B from the mount base 40. Note that when wiring is manufactured from the metal film F, the metal layer Ba formed on the surface of an insulating substrate Bb of the substrate B may be etched while maintaining a portion where the metal film F is formed.

[0047] According to the present embodiment, with the mask portion 65 of the masking member 60 being in contact with the substrate B, the air in the penetrating portions 68 can be sucked via the plurality of recessed grooves 67 by means of the suction device 81. Therefore, the air between the substrate B and the masking member does not need to be sucked before bringing the masking member into contact with the substrate B. Thus, even when gas generated during the electroplating accumulates within the plating solution L in the storing space 15a, the mask portion 65 of the masking member 60 is in contact with the substrate B at the time of film forming, and therefore, deformation of the mask portion 65 of the masking member 60 due to the pressure difference from the gas inside the storing space 15a can be suppressed. As a result, even when the film forming is repeatedly performed using the masking member 60, plastic deformation of the screen mask 62 of the masking member 60 can be suppressed.

[0048] Further, when the linear actuator 70 raises the container 15 to disengage the substrate B from the electrolyte membrane 13, the own weight of the plating solution L can be supported by the masking member 60 via the electrolyte membrane 13. Thus, the plastic deformation of the electrolyte membrane 13 can be suppressed due to the own weight of the plating solution L.EXAMPLE

[0049] A mask portion was formed on front and back sides of an LCP resin mesh portion having a wire diameter of 20 μm and 420 mesh, using silicone rubber, and as shown in FIG. 2, a masking member was produced by forming penetrating portions and recessed grooves each having a groove width of 100 μm in the mask portion. Note that the thickness of the mask portion was 20 μm for a portion disposed between an electrolyte membrane and the mesh portion and 30 μm for a portion disposed between the mesh portion and a substrate.

[0050] Next, a copper (Cu) substrate in a square having a thickness of 0.9 mm and one side length of 7.8 cm was prepared. The substrate was subjected to cathode electrolytic degreasing at 55° C. for 1 minute using an IC-200RM manufactured by JCU Corporation, and was then washed with pure water for 1 minute. Further, the substrate was immersed in a 10% dilute sulfuric acid at room temperature for 1 minute to be subjected to acid cleaning, and was then washed with pure water for 1 minute.

[0051] Thereafter, a metal film having a thickness of 5 μm was formed on the surface of the substrate by solid electro deposition (SED) using an apparatus having the same configuration as that of the film forming apparatus for forming a metal film described in the aforementioned embodiment. The film forming conditions were: film forming temperature: 42° C., plating solution: 1 mol / L copper sulfate+0.2 mol / L sulfuric acid, anode: phosphorus-containing copper plate, inter-electrode distance of anode-cathode: 2 mm, pressurization: 0.6 MPa, film forming arca: 38 cm2 / substrate size 61.4 cm2, and current: 7 ASD.

[0052] As Comparative Example 1, only the first recessed grooves were provided in the mask portion of the masking member, and after sucking the air between the substrate B and the masking member before bringing the masking member into contact with the substrate, a metal film that is the same as Example was formed. As Comparative Example 2, after sucking the air between the substrate B and the masking member without providing the recessed grooves in the masking member, a metal film that is the same as Example was formed. As Comparative Example 3, neither providing the recessed grooves in the mask portion of the masking member nor sucking the air between the substrate B and the masking member, a metal film that is the same as Example was formed.

[0053] Film forming of the metal film according to Example and Comparative Examples 1 to 3 was conducted 20 times and the number of defects of the metal film and the degree of deformation of the masking sheet of the masking member were observed. The results regarding the number of defects show that Example and Comparative Example 1 had one, Comparative Example 2 had two, and Comparative Example 3 had 32. Further, plastic deformation of the masking sheet of Example was insignificant as compared to Comparative Examples 1 to 3.

[0054] The embodiment of the present disclosure has been described in detail above, but the present disclosure is not limited to the aforementioned embodiment, and various design changes can be made within the scope without departing from the spirit of the present disclosure described in the scope of the claims.

Examples

example

[0049]A mask portion was formed on front and back sides of an LCP resin mesh portion having a wire diameter of 20 μm and 420 mesh, using silicone rubber, and as shown in FIG. 2, a masking member was produced by forming penetrating portions and recessed grooves each having a groove width of 100 μm in the mask portion. Note that the thickness of the mask portion was 20 μm for a portion disposed between an electrolyte membrane and the mesh portion and 30 μm for a portion disposed between the mesh portion and a substrate.

[0050]Next, a copper (Cu) substrate in a square having a thickness of 0.9 mm and one side length of 7.8 cm was prepared. The substrate was subjected to cathode electrolytic degreasing at 55° C. for 1 minute using an IC-200RM manufactured by JCU Corporation, and was then washed with pure water for 1 minute. Further, the substrate was immersed in a 10% dilute sulfuric acid at room temperature for 1 minute to be subjected to acid cleaning, and was then washed with pure wat...

Claims

1. A film forming apparatus for forming a metal film having a predetermined pattern on a surface of a substrate by electroplating, the film forming apparatus comprising:a container having an opening opposing the substrate, the opening covered by an electrolyte membrane with a plating solution contained in the container;a pressure increase mechanism that increases a pressure of the plating solution contained in the container; anda masking member disposed between the electrolyte membrane and the substrate, the masking member being attached to the container,whereinthe masking member includes a mesh portion in a sheet form through which the plating solution for the electroplating passes and a mask portion provided on front and back sides of the mesh portion, the mask portion being sandwiched between the electrolyte membrane and the substrate,in the mask portion, a plurality of penetrating portions that penetrates through the mask portion in accordance with the predetermined pattern to expose the mesh portion and a plurality of recessed grooves provided on a surface opposing the electrolyte membrane of the mask portion so as to be continuous with each of the penetrating portions are formed, andthe film forming apparatus further includes a suction device that sucks air in the penetrating portions via the plurality of recessed grooves, with the masking member being in contact with the substrate.

2. The film forming apparatus for forming a metal film according to claim 1, whereina frame that supports the mesh portion is provided at a peripheral edge of the masking member,the plurality of recessed grooves comprises:a plurality of first recessed grooves provided on the surface opposing the electrolyte membrane of the mask portion so as to connect the penetrating portions that are adjacent to each other; anda plurality of second recessed grooves provided on the surface opposing the electrolyte membrane of the mask portion so as to connect the penetrating portions and the frame,a third recessed groove continuous with the plurality of second recessed grooves is formed in the frame, andthe suction device sucks the air in the penetrating portions through the third recessed groove.

3. The film forming apparatus for forming a metal film according to claim 2, wherein intersecting grooves that intersect with the second recessed grooves and that are continuous with the third recessed groove are formed in the mask portion.

4. The film forming apparatus for forming a metal film according to claim 3, wherein the third recessed groove encircles the frame and is continuous with the second recessed grooves and the intersecting grooves.

5. A film forming method for forming a metal film using the film forming apparatus according to claim 1, the film forming method comprising the steps of:removing air in the penetrating portions via the plurality of recessed grooves by means of the suction device, with the masking member being in contact with the substrate;pressing the substrate with the electrolyte membrane via the mask portion by increasing a pressure of the plating solution contained in the container by means of the pressure increase mechanism, with the air removed; andforming the meal film on the surface of the substrate by electroplating, with the electrolyte membrane pressed.

Images