Pre-treatment unit for electrolyte membrane and pre-treatment method therefor

Abstract

A pre-treatment unit includes a cutting device in which a cut position is set, in which a strip-shaped electrolyte membrane is cut to have a predetermined length; a boiling device including a fixing jig for detachably fixing a plurality of pieces of an electrolyte membrane with a gap therebetween; and a pair of clips attached to the strip-shaped electrolyte membrane across a width direction of the strip-shaped electrolyte membrane. The fixing jig is provided with locking portions that lock the pair of clips attached to each piece of the electrolyte membrane to the fixing jig such that the plurality of pieces of the electrolyte membrane is stretched with a gap therebetween.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese patent application JP 2024-111280 filed on Jul. 10, 2024, the entire content of which is hereby incorporated by reference into this application.BACKGROUNDTechnical Field

[0002] The present disclosure relates to a pre-treatment unit for an electrolyte membrane and a pre-treatment method therefor.Background Art

[0003] As a technique of this type, for example, JP 2014-122377 A proposes a film forming apparatus that forms a metal film on a substrate. The film forming apparatus includes an electrolyte membrane. The film forming apparatus is an apparatus that forms a metal film on a substrate by electroplating, with the electrolyte membrane brought into contact with the substrate. For the electrolyte membrane used in the film forming apparatus, as pre-treatment, a strip-shaped electrolyte membrane is cut into an appropriate length. Thereafter, as shown in for example, JP 2020-109215 A, the electrolyte membrane is boiled in a treatment liquid to remove impurities adhering to the electrolyte membrane.SUMMARY

[0004] However, wrinkling may occur in the electrolyte membrane when the electrolyte membrane is cut. Furthermore, like the technique described in JP 2020-109215 A, also when electrolyte membranes are boiled, the adjacent electrolyte membranes tend to be stuck to each other and wrinkling may occur. When the wrinkled electrolyte membrane is boiled, it may be difficult to uniformly remove the impurities from the electrolyte membrane.

[0005] The present disclosure has been made in view of such a point, and provides a pre-treatment unit for an electrolyte membrane and a pre-treatment method therefor, which can uniformly remove impurities from the electrolyte membrane while suppressing the occurrence of wrinkling in the electrolyte membrane during cutting and boiling.

[0006] In view of the foregoing issue, the pre-treatment unit for the electrolyte membrane according to the present disclosure is a pre-treatment unit for an electrolyte membrane used in a film forming apparatus that forms a metal film on a surface of a substrate via the electrolyte membrane by electroplating, with the electrolyte membrane brought into contact with the substrate. The pre-treatment unit includes: a cutting device including a path forming member that forms a transfer path on which a strip-shaped electrolyte membrane is horizontally paid off from a rolled-up electrolyte membrane and a leading end portion of the strip-shaped electrolyte membrane is vertically hung down, wherein a cut position is set, in which the strip-shaped electrolyte membrane is cut into a plurality of pieces of the electrolyte membrane in a horizontally extending portion of the strip-shaped electrolyte membrane, each piece having a predetermined length; a boiling device including a fixing jig for detachably fixing the plurality of pieces of the electrolyte membrane with a gap therebetween, and a boiling tank for immersing the plurality of pieces of the electrolyte membrane together with the fixing jig and boiling the plurality of pieces of the electrolyte membrane; and a pair of clips attached to the leading end portion of the strip-shaped electrolyte membrane before cut and a portion adjacent to the cut position, across a width direction of the strip-shaped electrolyte membrane, so as to be arranged at opposite ends in a length direction of each piece of the electrolyte membrane cut by the cutting device. The fixing jig is provided with locking portions that lock the pair of clips attached to each piece of the electrolyte membrane to the fixing jig such that the plurality of pieces of the electrolyte membrane is stretched with a gap therebetween.

[0007] In some embodiments, the film forming apparatus includes an apparatus body having a housing recess in which a plating solution is contained, and a frame attached to the apparatus body together with the electrolyte membrane to cover the housing recess with the electrolyte membrane. The frame includes an inner frame on which the electrolyte membrane is stretched, and an outer frame that sandwiches a peripheral edge of the electrolyte membrane with the inner frame. The pre-treatment unit further includes a film tensioning device for stretching the electrolyte membrane on an opening to cover the opening of the inner frame with the boiled electrolyte membrane from above. The film tensioning device has a mount base on which the inner frame is placed. A length of the mount base along a horizontal direction is shorter than a length of the electrolyte membrane such that tension acts on the electrolyte membrane due to a weight of the pair of clips attached to the opposite ends, with the opening of the inner frame covered with the electrolyte membrane from above.

[0008] In some embodiments, the mount base includes an engagement projection that engages the inner frame to fill an internal space of the inner frame from below. In some embodiments, the film tensioning device further includes a guide mechanism that guides the outer frame to the inner frame to fit the outer frame to the inner frame from above, with the opening of the inner frame covered with the electrolyte membrane from above.

[0009] In a pre-treatment method for the electrolyte membrane using the above-described pre-treatment unit, the clips are attached to the leading end portion of the strip-shaped electrolyte membrane and the portion adjacent to the cut position, and the strip-shaped electrolyte membrane is cut in the cut position with tension applied to the strip-shaped electrolyte membrane with a weight of the clip attached to the leading end portion. Next, the plurality of pieces of the electrolyte membrane with a gap therebetween is stretched by locking the pair of clips attached to each piece of the electrolyte membrane to the locking portions of the fixing jig, and the plurality of pieces of the electrolyte membrane is immersed together with the fixing jig in the boiling tank, and the plurality of pieces of the electrolyte membrane is boiled. Further, tension is applied to the electrolyte membrane with the weight of the pair of clips attached to the opposite ends by covering the opening of the inner frame with the electrolyte membrane from above while an engagement projection is engaged with the inner frame to fill the internal space of the inner frame from below, the electrolyte membrane is sandwiched between the outer frame and the inner frame by guiding the outer frame to the inner frame by the guide mechanism, and the electrolyte membrane is stretched on the opening of the frame.

[0010] According to the present disclosure, it is possible to uniformly remove impurities from the electrolyte membrane while suppressing the occurrence of wrinkling in the electrolyte membrane during cutting and boiling.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A is a schematic diagram of a cutting device of a pre-treatment unit for an electrolyte membrane according to an embodiment of the present disclosure;

[0012] FIG. 1B is a schematic diagram of a clip attached to the electrolyte membrane shown in FIG. 1A;

[0013] FIG. 2A is a schematic perspective view of a fixing jig of a boiling device of the pre-treatment unit for the electrolyte membrane according to the embodiment of the present disclosure;

[0014] FIG. 2B is a schematic diagram of the boiling device;

[0015] FIG. 3A is a schematic diagram of a film tensioning device of the pre-treatment unit for the electrolyte membrane according to the embodiment of the present disclosure;

[0016] FIG. 3B is a schematic diagram showing a film tensioned state by a film tensioning device;

[0017] FIG. 4A is a schematic diagram of a state where the electrolyte membrane after film tensioning is attached to an apparatus body of the film forming apparatus;

[0018] FIG. 4B is a schematic diagram for explaining a film forming state by the film forming apparatus; and

[0019] FIG. 5 is a flowchart of a pre-treatment method using the pre-treatment unit for the electrolyte membrane according to the embodiment of the present disclosure.DETAILED DESCRIPTION

[0020] Hereinafter, a pre-treatment unit 10 for an electrolyte membrane 13 according to the present embodiment will be described referring to the drawings. The pre-treatment unit 10 according to the present embodiment includes a cutting device 30 shown in FIG. 1A, a boiling device 40 shown in FIG. 2B, a film tensioning device 60 shown in FIG. 3A, and a clip 20 shown in FIG. 1B. It is noted that a pre-treatment method for the electrolyte membrane 13 is a treatment method including a cutting step S1, a boiling step S2, and a film tensioning step S3 shown in FIG. 5, performed using the pre-treatment unit 10. It is noted that the electrolyte membrane 13 is used in the film forming apparatus 1 as shown in FIG. 4A and FIG. 4B (described later). As shown in FIG. 4A, the electrolyte membrane 13 is attached to an apparatus body 1A of the film forming apparatus 1 while being stretched on a frame 17. As shown in FIG. 4B, the film forming apparatus 1 forms a metal film F on a surface Ba of a substrate B via the electrolyte membrane 13 by electroplating, with the electrolyte membrane 13 brought into contact with the substrate B.

[0021] The electrolyte membrane 13 is an electrolyte membrane (ion exchange film) through which metal ions pass, and examples thereof may include, but are not limited to, a polymeric resin having an ion-exchange function such as a fluorine-based resin of Nafion (registered trademark) available from DuPont, a hydrocarbon-based resin, a polyamic acid resin, SELEMION (CMV, CMD, CMF series) available from AGC Inc. The film thickness of the electrolyte membrane 13 may be in the range of 5 μm to 200 μm. Specifically, the film thickness may be in the range of 20 μm to 160 μm. As shown in FIG. 1A, the cutting device 30 peels off a back sheet BS from a strip-shaped electrolyte membrane 13B paid off from a rolled-up electrolyte membrane 13A and cuts the strip-shaped electrolyte membrane 13B into a piece of the electrolyte membrane 13 in a sheet form (see, for example, FIG. 2A).

[0022] The cutting device 30 includes a mount 31. The mount 31 is provided with a mandrel 32 for paying off the rolled-up electrolyte membrane 13A, and a mandrel 33 for winding up the back sheet BS. The cutting device 30 includes a path forming member 34 that forms a transfer path on which the strip-shaped electrolyte membrane 13B is transferred. The transfer path is a passing route from the rolled-up electrolyte membrane 13A to the strip-shaped electrolyte membrane 13B. The path forming member 34 forms the transfer path of the strip-shaped electrolyte membrane 13B such that the strip-shaped electrolyte membrane 13B is horizontally paid off from the rolled-up electrolyte membrane 13A and a leading end portion of the strip-shaped electrolyte membrane 13B is vertically hung down. Specifically, the path forming member 34 includes a peel-off roller 34A provided on the upstream side and a change roller 34B provided on the downstream side for changing a transfer direction. The peel-off roller 34A and the change roller 34B are arranged horizontally with a distance therebetween.

[0023] With the above configuration, a transfer path is formed between the peel-off roller 34A and the change roller 34B in which the strip-shaped electrolyte membrane 13B is horizontally paid off from the rolled-up electrolyte membrane 13A. Further, a transfer path is formed below the change roller 34B to cause the leading end portion 13a of the strip-shaped electrolyte membrane 13B to be vertically hung down. Meanwhile, a roller 35 is provided below the peel-off roller 34A. With a transfer path of the back sheet BS formed downward, the back sheet BS can be peeled off from the strip-shaped electrolyte membrane 13B, and the back sheet BS can be wound up by the mandrel 33.

[0024] In the mount 31 of the cutting device 30, a positioning portion 31a for determining the leading end position of the strip-shaped electrolyte membrane 13B paid off is set. Further, in the mount 31, a cut position 31b is set, in which the strip-shaped electrolyte membrane 13B is cut into a plurality of pieces in a horizontally extending portion of the strip-shaped electrolyte membrane 13B, each piece having a predetermined length L1 (see FIG. 2A). In the cut position 31b, the strip-shaped electrolyte membrane 13B is cut with a cutting edge 38. Between the positioning portion 31a and the cut position 31b, the electrolyte membrane 13B is cut to have the predetermined length L1. The positioning portion 31a and the cut position 31b of the mount 31 may be set by a mark or the like, or may be set by a scale for measuring the predetermined length L1 of the strip-shaped electrolyte membrane 13B.

[0025] In the present embodiment, as shown in FIG. 2A, a pair of clips 20, 20 is disposed on the opposite ends in the length L1 direction of the cut electrolyte membrane 13. As shown in FIG. 1A, before the strip-shaped electrolyte membrane 13B is cut by the cutting device 30, the clips 20 are attached to the leading end portion 13a of the strip-shaped electrolyte membrane 13B and a downstream portion 13b adjacent to the cut position 31b. As used herein, the term “downstream” means the downstream along the transfer direction of the strip-shaped electrolyte membrane 13B. Also, upstream of the cut position 31b, the clip 20 is attached to an upstream portion 13c adjacent to the cut position 31b. After the strip-shaped electrolyte membrane 13 is cut, the clip 20 attached to the upstream portion 13c becomes the clip 20 attached to the leading end portion of the strip-shaped electrolyte membrane 13B.

[0026] As shown in FIG. 1B, each clip 20 is attached to the strip-shaped electrolyte membrane 13B across the width direction of the strip-shaped electrolyte membrane 13B. The clip 20 has a pair of arms 21, 22 coupled via a hinge 25. The arm 22 of the pair is provided with a fitting hook 23 with which a tip portion 24 of the arm 21 of the pair is detachably fitted. This allows the strip-shaped electrolyte membrane 13B to be sandwiched between the pair of arms 21, 22. The clip 20 is made of a resin material such as a polyamide-resin, and is made of a resin material capable of withstanding the boiling temperature in the boiling step S2 (described later).

[0027] In the cutting step S1 shown in FIG. 5, the pair of clips 20, 20 is attached to the leading end portion 13a of the strip-shaped electrolyte membrane 13B and the downstream portion 13b adjacent to the cut position 31b. Accordingly, tension acts on the strip-shaped electrolyte membrane 13B due to the weight of the clip 20 attached to the leading end portion 13a. The strip-shaped electrolyte membrane 13B is cut in the cut position 31b with tension applied to the strip-shaped electrolyte membrane 13B. At this time, since the tension uniformly acts on the strip-shaped electrolyte membrane 13B in the width direction, the strip-shaped electrolyte membrane 13B is easily cut, and wrinkling hardly occurs in the strip-shaped electrolyte membrane 13B after cutting.

[0028] It is noted that before cutting, the clip 20 may be attached also to the upstream portion 13c adjacent to the cut position 31b so as to sandwich the cut position 31b. After the strip-shaped electrolyte membrane 13 is cut, the clip 20 attached to the upstream portion 13c becomes the clip 20 attached to the leading end portion of the strip-shaped electrolyte membrane 13B. Repeating such a work can prepare a plurality of pieces of the electrolyte membrane 13 with the clips 20 attached to the opposite ends thereof as shown in FIG. 2A.

[0029] As shown in FIG. 2A and FIG. 2B, the boiling device 40 includes a fixing jig 40A for detachably fixing the plurality of pieces of the electrolyte membrane 13 with a gap therebetween, and a boiling tank 40B for immersing the pieces of the electrolyte membrane 13 together with the fixing jig 40A and boiling the pieces of the electrolyte membrane 13. The fixing jig 40A includes a pair of side walls 41, 41 that face each other. The side walls 41, 41 are coupled together by a pair of upper coupling beams 42, 42 and a pair of lower coupling beams 43, 43. Further, as shown in FIG. 2A, the pair of side walls 41, 41 of the fixing jig 40A is provided with locking portions 44 that lock the pair of clips 20, 20 attached to the piece of the electrolyte membrane 13 to the fixing jig 40A to stretch the plurality of pieces of the electrolyte membrane 13 with a gap. In the present embodiment, the locking portion 44 is a guide groove for guiding the clip 20 to lock the clip 20. The guide groove is a groove formed in accordance with the shape of the clip 20. The form of the guide groove is not particularly limited as long as the clip 20 does not float during boiling and can be fixed to the fixing jig 40A. The guide grooves are formed with a gap on the wall surface of the side walls 41. The piece of the electrolyte membrane 13 in the stretched state can be attached to the fixing jig 40A by guiding the pair of clips 20, 20 attached to the piece of the electrolyte membrane 13 from above to engagement grooves. The boiling tank 40B is provided with a heater 48.

[0030] In the boiling step S2 shown in FIG. 5, the pair of clips 20, 20 attached to the piece of the electrolyte membrane 13 is locked to the opposing locking portions 44 of the fixing jig 40A. This allows the pieces of the electrolyte membrane 13 to be stretched with a gap therebetween. After that, the pieces of the electrolyte membrane 13 are immersed together with the fixing jig 40A in the boiling tank 40B, and boiled. Specifically, water (e.g., pure water) contained in the boiling tank 40B is heated by the heater 48 to boil the pieces of the electrolyte membrane 13 immersed together with the fixing jig 40A. In this way, by using the pair of clips 20, 20 attached when cutting the strip-shaped electrolyte membrane 13B, it is possible to reduce the occurrence of wrinkling in each piece of the electrolyte membrane 13 without the plurality of pieces of the electrolyte membrane 13 adhering to each other. By boiling the pieces of the electrolyte membrane 13 in this condition, the impurities can be uniformly removed from the pieces of the electrolyte membrane 13, and the pieces of the electrolyte membrane 13 can undergo uniform swelling.

[0031] The film tensioning device 60 is a device that stretches the electrolyte membrane 13 on the frame 17 of the film forming apparatus 1 (described later). Here, as shown in FIG. 4A, the film forming apparatus 1 includes the apparatus body 1A having a housing recess 15a in which a plating solution L is contained, and the frame 17 attached to the apparatus body 1A together with the electrolyte membrane 13 to cover the housing recess 15a with the electrolyte membrane 13. The frame 17 includes an inner frame 17A that allows the electrolyte membrane 13 to be stretched on an opening of the frame 17, and an outer frame 17B that sandwiches a peripheral edge of the electrolyte membrane 13 with the inner frame 17A. The inner frame 17A and the outer frame 17B are both rectangular frames. As shown in FIG. 3A and FIG. 3B, in the film tensioned state, the inner frame 17A and the outer frame 17B fit each other, and an outer peripheral surface 17a of the inner frame 17A and an inner peripheral surface 17b of the outer frame 17B face each other via the peripheral edge of the electrolyte membrane 13.

[0032] Specifically, the film tensioning device 60 stretches the electrolyte membrane 13 on the opening of the inner frame 17A to cover the opening of the inner frame 17A with the boiled electrolyte membrane 13 from above. The film tensioning device 60 has a mount base 61 on which the inner frame 17A is placed. The mount base 61 includes an engagement projection 62 that engages the inner frame 17A to fill an internal space S of the inner frame 17A from below. By providing the engagement projection 62 inside of the inner frame 17A, it is possible to prevent the electrolyte membrane 13 from entering the inside of the inner frame 17A during film tensioning. The engagement projection 62 may be made of a porous material that is softer than the body of the mount base 61 and the inner frame 17A, for example. Examples of the material of the engagement projection 62 may include foamed resin material. Further, since the inner frame 17A is positioned with respect to the mount base 61, the outer frame 17B can be accurately fitted to the inner frame 17A by a guide mechanism 68 (described later).

[0033] The film tensioning device 60 further includes the guide mechanism 68 that guides the outer frame 17B to the inner frame 17A to fit the outer frame 17B to the inner frame 17A from above, with the opening of the inner frame 17A covered with the electrolyte membrane 13 from above. In the present embodiment, the guide mechanism 68 is a linear guide, and to the linear guide, a support member 67 that slidably supports a holding member 66 that holds the outer frame 17B is attached. The support member 67 is movable in an up-down direction by the linear guide. The pair of holding members 66, 66 is slidable with respect to the support member 67 in a horizontal direction which the pair of holding members 66, 66 faces.

[0034] The length L2 of the mount base 61 along the horizontal direction is shorter than the length L1 of the electrolyte membrane 13. Accordingly, tension can act uniformly on the electrolyte membrane 13 due to the weight of the pair of clips 20, 20 attached to the opposite ends, with the opening of the inner frame 17A covered with the electrolyte membrane 13 from above. Consequently, it is possible to reduce the occurrence of wrinkling in the electrolyte membrane 13 stretched on the inner frame 17A. In addition, a corner 64 of the mount base 61, which contacts the electrolyte membrane 13, is rounded off by chamfering or the like, so that any damage to the electrolyte membrane 13 can be suppressed.

[0035] In the present embodiment, in the film tensioning step S3 shown in FIG. 5, the engagement projection 62 of the mount base 61 is engaged with the inner frame 17A to fill the internal space S of the inner frame 17A from below. In this condition, when the opening of the inner frame 17A is covered with the electrolyte membrane 13 from above, tension is applied to the electrolyte membrane 13 with the weight of the pair of clips 20, 20 attached to the opposite ends of the electrolyte membrane 13. Next, the outer frame 17B is moved down by the guide mechanism 68, and the outer frame 17B is guided to the inner frame 17A. The peripheral edge of the electrolyte membrane 13 is sandwiched between the outer frame 17B and the inner frame 17A, and the electrolyte membrane 13 is stretched on the opening of the frame 17. After that, the support member 67 is allowed to slide and the frame 17 including the outer frame 17B is detached from the support member 67. Furthermore, the electrolyte membrane 13 is cut to separate the clips 20 from the frame 17.

[0036] Next, in an attaching step S4 shown in FIG. 5, the electrolyte membrane 13 is attached to the apparatus body 1A of the film forming apparatus 1. As shown in FIG. 4A, the film forming apparatus 1 includes the apparatus body 1A and the above-described frame 17. The apparatus body 1A includes an anode 11 and a housing 15 that houses the anode 11 and the plating solution L. The film forming apparatus 1 further includes a power supply 14 for applying a voltage between the anode 11 and the substrate B, a mount base 19 on which the substrate B is placed, and a linear motion actuator 18 for raising and lowering the housing 15.

[0037] The housing 15 includes the housing recess 15a in which the plating solution L is contained. The anode 11 is disposed in the housing recess 15a of the housing 15. An opening 15d is formed on a side of the housing recess 15a nearer to the substrate B. By fitting the frame 17 covered with the electrolyte membrane 13 to the housing 15, the electrolyte membrane 13 can be attached to the apparatus body 1A. Accordingly, the plating solution L in the housing recess 15a is sealed by the electrolyte membrane 13 with the plating solution L contained therein.

[0038] The housing 15 includes a supply port 15b for supplying the plating solution L to the housing recess 15a, and a discharge port 15c for discharging the plating solution L from the housing recess 15a. The supply port 15b and the discharge port 15c are formed to have the housing recess 15a placed therebetween. The film forming apparatus 1 further includes a tank 58, a supply pipe 51, a discharge pipe 52, and a circulation pump 59. The tank 58 contains the plating solution L. The supply pipe 51 connects the tank 58 and the housing 15, the supply pipe 51 is provided with the circulation pump 59. The discharge pipe 52 connects the tank 58 and the housing 15, and the discharge pipe 52 is provided with a pressure regulating valve 54. The pressure regulating valve 54 adjusts the pressure (fluid pressure) of the plating solution L in the housing recess 15a to a predetermined pressure.

[0039] In the present embodiment, driving the circulation pump 59 allows the plating solution L to be sucked from the tank 58 into the supply pipe 51, and then pressure-fed to the housing recess 15a through the supply port 15b. The plating solution L in the housing recess 15a returns to the tank 58 through the discharge port 15c. This forms a circulation path 50.

[0040] Next, in a film forming step S5 shown in FIG. 5, a metal film F is formed on the substrate B. Here, the substrate B functions as a cathode. The material of the substrate B is not particularly limited as long as it functions as a cathode (i.e., a conductive surface). The substrate B may be made of a metal material such as for example, aluminum or copper. The plating solution L is a liquid containing the metal of the metal film to be formed in the state of ions. Examples of the metal include copper, nickel, gold, silver, iron, or the like. The plating solution L is a solution obtained by dissolving (ionizing) these metals with an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, or pyrophosphoric acid. Examples of the solvent of the solution may include water and alcohol.

[0041] As shown in FIG. 4B, the substrate B is placed in a recess 19a of the mount base 19, and the electrolyte membrane 13 attached to the housing 15 is brought into contact with the substrate B by the linear motion actuator 18, and the circulation pump 59 is driven to press the substrate B by the electrolyte membrane 13 with a fluid pressure of the plating solution L in the housing recess 15a. Accordingly, the electrolyte membrane 13 conforms to the substrate B, and the plating solution L in the housing 15 has a constant pressure set by the pressure regulating valve 54. This allows the electrolyte membrane 13 to uniformly press the surface of the substrate B with the regulated fluid pressure of the plating solution L in the housing 15.

[0042] In this pressing state, a voltage is applied between the anode 11 and the substrate B by the power supply 14. By electroplating, metal ions in the plating solution are allowed to pass through the electrolyte membrane 13, and a metal film F can be formed on the surface of the substrate B by electroplating. In the present embodiment, during film forming, the metal ions in the plating solution L are allowed to uniformly pass through the electrolyte membrane 13 by electroplating, in a state where the electrolyte membrane 13 having undergone uniform swelling is in contact with the substrate B, and thus it is possible to form a homogeneous metal film F having a uniform thickness.

Claims

1. A pre-treatment unit for an electrolyte membrane used in a film forming apparatus that forms a metal film on a surface of a substrate via the electrolyte membrane by electroplating, with the electrolyte membrane brought into contact with the substrate,the pre-treatment unit comprising:a cutting device including a path forming member that forms a transfer path on which a strip-shaped electrolyte membrane is horizontally paid off from a rolled-up electrolyte membrane and a leading end portion of the strip-shaped electrolyte membrane is vertically hung down, wherein a cut position is set, in which the strip-shaped electrolyte membrane is cut into a plurality of pieces of the electrolyte membrane in a horizontally extending portion of the strip-shaped electrolyte membrane, each piece having a predetermined length;a boiling device including a fixing jig for detachably fixing the plurality of pieces of the electrolyte membrane with a gap therebetween, and a boiling tank for immersing the plurality of pieces of the electrolyte membrane together with the fixing jig and boiling the plurality of pieces of the electrolyte membrane; anda pair of clips attached to the leading end portion of the strip-shaped electrolyte membrane before cut and a portion adjacent to the cut position, across a width direction of the strip-shaped electrolyte membrane, so as to be arranged at opposite ends in a length direction of each piece of the electrolyte membrane cut by the cutting device,wherein the fixing jig is provided with locking portions that lock the pair of clips attached to each piece of the electrolyte membrane to the fixing jig such that the plurality of pieces of the electrolyte membrane is stretched with a gap therebetween.

2. The pre-treatment unit for the electrolyte membrane according to claim 1,wherein the film forming apparatus includes an apparatus body having a housing recess in which a plating solution is contained, and a frame attached to the apparatus body together with the electrolyte membrane to cover the housing recess with the electrolyte membrane,wherein the frame includes an inner frame on which the electrolyte membrane is stretched, and an outer frame that sandwiches a peripheral edge of the electrolyte membrane with the inner frame,the pre-treatment unit further comprising a film tensioning device for stretching the electrolyte membrane on an opening to cover the opening of the inner frame with the boiled electrolyte membrane from above,wherein the film tensioning device has a mount base on which the inner frame is placed, andwherein a length of the mount base along a horizontal direction is shorter than a length of the electrolyte membrane such that tension acts on the electrolyte membrane due to a weight of the pair of clips attached to the opposite ends, with the opening of the inner frame covered with the electrolyte membrane from above.

3. The pre-treatment unit for the electrolyte membrane according to claim 2, wherein the mount base includes an engagement projection that engages the inner frame to fill an internal space of the inner frame from below.

4. The pre-treatment unit for the electrolyte membrane according to claim 3, wherein the film tensioning device further includes a guide mechanism that guides the outer frame to the inner frame to fit the outer frame to the inner frame from above, with the opening of the inner frame covered with the electrolyte membrane from above.

5. A pre-treatment method for the electrolyte membrane using the pre-treatment unit according to claim 4, the pre-treatment method comprising:attaching the clips to the leading end portion of the strip-shaped electrolyte membrane and the portion adjacent to the cut position and cutting the strip-shaped electrolyte membrane in the cut position with tension applied to the strip-shaped electrolyte membrane with a weight of the clip attached to the leading end portion;stretching the plurality of pieces of the electrolyte membrane with a gap therebetween by locking the pair of clips attached to each piece of the electrolyte membrane to the locking portions of the fixing jig, and immersing the plurality of pieces of the electrolyte membrane together with the fixing jig in the boiling tank and boiling the plurality of pieces of the electrolyte membrane; andapplying tension to the electrolyte membrane with the weight of the pair of clips attached to the opposite ends by covering the opening of the inner frame with the electrolyte membrane from above while an engagement projection is engaged with the inner frame to fill the internal space of the inner frame from below, sandwiching the electrolyte membrane between the outer frame and the inner frame by guiding the outer frame to the inner frame by the guide mechanism, and stretching the electrolyte membrane on the opening of the frame.

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