JP3859451B2 - Electroplating apparatus and electroplating method for film carrier tape for electronic mounting parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electroplating apparatus and a plating method for performing electroplating on a long film-like conductor. Specifically, the present invention relates to a film carrier tape for mounting electronic components (TAB (Tape Automated Bonding) tape, T-BGA (Tape). The present invention relates to an electroplating apparatus and a plating method for forming a ball grid array (Tape), a tape CSP (Chip Size Package), an ASIC (Application Specific Integrated Circuit) tape, etc. (hereinafter simply referred to as “film carrier tape for mounting electronic components”).
[0002]
[Prior art]
With the development of the electronics industry, the demand for printed wiring boards for mounting electronic components such as ICs (integrated circuits) and LSIs (large scale integrated circuits) has increased rapidly. High functionality is demanded, and recently, a mounting method using a TAB tape, a T-BGA tape, an ASIC tape, or the like has been adopted as a method for mounting these electronic components. In particular, the importance is increasing in the electronic industry using a liquid crystal display element (LCD) such as a personal computer, for which high definition, thinning, and narrowing of the frame area of a liquid crystal screen are desired.
[0003]
For a substrate used for manufacturing such a TAB tape, for example, a very thin conductive layer is provided on a continuous insulating film, a metal foil is bonded, or a conductive layer is provided by sputtering, vacuum deposition or electroless plating, A substrate in which a wiring pattern is formed with a predetermined thickness by electroplating the conductive layer patterned in a predetermined shape.
[0004]
In this electroplating process, an insulating film having a conductive layer provided in a predetermined shape is conveyed by a reel-to-reel method, and is brought into contact with a power feeding roller as a cathode outside the plating tank while supplying power to the inside of the plating bath. A continuous electroplating apparatus is used in which a plating layer is formed on a conductive layer by an anode.
[0005]
According to this continuous plating apparatus, electroplating can be continuously applied to an insulating film provided with a conductive layer.
[0006]
In such a continuous electroplating apparatus, it is strongly desired to form a thick plating layer at a high speed.
[0007]
[Problems to be solved by the invention]
Thus, in order to form a TAB tape at high speed, it is necessary to lengthen the length of the plating tank in which the insulating film is immersed.
[0008]
However, if the length of the plating tank is increased, the current supplied by the pair of cathodes provided so as to be in contact with the plating leads on both ends outside the plating tank must be increased in proportion to the length of the plating tank. Therefore, there is a problem that the plating layer is burnt or the difference in electric resistance between the plating leads becomes large, and a current density of a certain level or more cannot be secured, so that a plating layer is not partially formed.
[0009]
In view of such circumstances, it is an object of the present invention to provide an electroplating apparatus and a plating method in which the difference in electric resistance between plating leads is reduced to reduce burn plating and yield.
[0010]
[Means for Solving the Invention]
The first aspect of the present invention that solves the above problems is the longitudinal direction of the plating tank in a state where a continuous insulating film having a wiring pattern made of a conductive layer on the surface is immersed in a plating solution held in the plating tank. In the electroplating apparatus, in which the conductive layer is plated while being transported along a film carrier tape for mounting an electronic component, the electroplating apparatus is provided in the plating tank so as to face the insulating film at a predetermined interval. An anode disposed; a pair of cathodes provided on both outer sides in the longitudinal direction of the plating tank and in contact with the conductive layer provided on the insulating film; and at least a central portion in the longitudinal direction of the plating tank And an intermediate cathode that is provided so as not to be immersed in the plating solution and is in contact with a part of the conductive layer exposed from the plating solution. In electroplating apparatus according to claim Rukoto.
[0011]
In the first aspect, by supplying power from the cathode and the intermediate cathode, the difference in the longitudinal direction of the electrical resistance of the conductive layer immersed in the plating solution can be reduced, and a current exceeding a certain level in all regions. The density can be secured. Thereby, it is possible to reliably supply power with a low current.
[0012]
According to a second aspect of the present invention, in the first aspect, a plating lead is formed by the conductive layer along the width direction end portion of the insulating film continuously to the wiring pattern, and the intermediate cathode is The electroplating apparatus is provided so as to be in contact with the plating lead.
[0013]
In the second aspect, by bringing the intermediate cathode and the plating lead into contact with each other, it is possible to reliably supply power to the central portion of the conductive layer immersed in the plating solution from the intermediate cathode.
[0014]
According to a third aspect of the present invention, in the second aspect, the insulating film is transported so that a part of the plating lead is exposed from the liquid surface of the plating solution at least at a central portion in the longitudinal direction of the plating tank. The electroplating apparatus is characterized by the above.
[0015]
In the third aspect, since it is possible to reliably supply power to the conductive layer at the center, a stable plating layer can be formed.
[0016]
According to a fourth aspect of the present invention, there is provided the electroplating apparatus according to the first or second aspect, wherein a plurality of the intermediate cathodes are provided at a predetermined interval.
[0017]
In the fourth aspect, the difference in the longitudinal direction of the electrical resistance of the conductive layer immersed in the plating solution can be reliably reduced by a plurality of intermediate cathodes, and power can be supplied with a small current.
[0018]
According to a fifth aspect of the present invention, in the electroplating apparatus according to any one of the first to fourth aspects, the intermediate cathode is a contact roll provided rotatably.
[0019]
In the fifth aspect, power can be reliably and easily supplied by the contact roll.
[0020]
According to a sixth aspect of the present invention, a continuous insulating film having a wiring pattern made of a conductive layer on the surface is immersed in a plating solution held in a plating tank, and the anode and the plating liquid provided in the plating tank are immersed in the plating solution. Plating as a film carrier tape for mounting electronic components by plating on the conductive layer while transporting along the longitudinal direction of the plating tank in a state where a voltage is applied between the cathode and the cathode in contact with the immersed conductive layer In the method, in addition to the cathodes provided outside the both ends in the longitudinal direction of the plating tank, an intermediate cathode that contacts the conductive layer is provided at least in the vicinity of the central part in the longitudinal direction of the plating tank to supply power. The electroplating method is characterized by the above.
[0021]
In the sixth aspect, by supplying power from the cathode and the intermediate cathode, the difference in the longitudinal direction of the electrical resistance of the conductive layer immersed in the plating solution can be reduced, and a current exceeding a certain level in all regions. The density can be secured. Accordingly, it is possible to reliably supply power at a low voltage, and it is possible to form a stable plating layer in a short time.
[0022]
According to a seventh aspect of the present invention, in the sixth aspect, a plating lead is formed by the conductive layer along the width direction end portion of the insulating film continuously with the wiring pattern, and the intermediate cathode is formed as the intermediate cathode. An electroplating method is characterized in that power is supplied so as to contact the plating lead.
[0023]
In the seventh aspect, by bringing the intermediate cathode and the plating lead into contact with each other, power can be reliably supplied from the intermediate cathode to the central portion of the conductive layer immersed in the plating solution.
[0024]
An eighth aspect of the present invention is the seventh aspect according to the seventh aspect, wherein the insulating film is exposed so that the plating lead provided at the end portion in the width direction of the insulating film is exposed at least in the longitudinal direction of the plating tank. It is in the electroplating method characterized by conveying.
[0025]
In the eighth aspect, since it is possible to reliably supply power to the conductive layer at the center, a stable plating layer can be formed.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electronic component mounting board according to an embodiment of the present invention will be described together with a manufacturing method and usage examples. Of course, it goes without saying that the present invention is not limited to this.
[0027]
First, an example of a semiconductor package plated by the electroplating apparatus of the present invention will be described.
[0028]
FIG. 1 is a front view illustrating an example of a film carrier tape for mounting electronic components according to Embodiment 1, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
[0029]
As shown in FIG.1 and FIG.2, the film carrier tape 10 of this embodiment is a TAB tape, and the several wiring pattern 12 is continuously formed in the one surface side of the tape-shaped insulating film 11. As shown in FIG. . The insulating film 11 has sprocket holes 13 for transfer on both sides in the width direction at regular intervals. In general, an electronic component 30 such as an IC is mounted while being transferred, and each wiring pattern is mounted after the electronic component 30 is mounted. Cut every 12th.
[0030]
In addition, sprocket holes 13 are provided at both ends in the width direction of the insulating film 11. In addition, the insulating film 11 can be formed with through holes for various purposes such as through holes for alignment, defective package display, and package outer shape, together with the sprocket holes 13.
[0031]
In this wiring pattern 12, a region excluding the device side connection terminal 14 connected to the electronic component 30 to be mounted, the input side external connection terminal 15 connected to the outside, and the output side external connection terminal 16 is covered with the solder resist layer 17. It has been broken.
[0032]
Here, as the insulating film 11, a material having flexibility and chemical resistance and heat resistance can be used. Examples of the material for the insulating film 11 include polyester, polyamide, polyimide, and the like. Particularly preferred is wholly aromatic polyimide having a biphenyl skeleton (for example, trade name: Upilex; Ube Industries, Ltd.). In addition, generally the thickness of the insulating film 11 is 25-125 micrometers, Preferably, it is 50-75 micrometers.
[0033]
In such an insulating film 11, a device hole 18 is formed in a predetermined region of the wiring pattern 12 by punching. The device side connection terminal 14 of the wiring pattern 12 is provided up to the edge of the device hole 18 and is connected to the electronic component 30 in a process described later.
[0034]
The wiring pattern 12 is generally formed by patterning a conductive layer 20 such as a conductor foil made of copper or aluminum on one surface where the device holes 18 and the sprocket holes 13 formed in the insulating film 11 are formed. Is formed. Such a conductive layer 20 may be directly laminated on the insulating film 11 or may be formed by thermocompression bonding or the like via an adhesive layer. The thickness of the conductive layer 20 is, for example, 6 to 70 μm, or preferably 8 to 35 μm. The conductive layer 20 made of a conductive foil is preferably a copper foil, particularly an electrolytic copper foil in consideration of etching characteristics, operability, and the like.
[0035]
Instead of providing the conductor foil on the insulating film 11, for example, a polyimide precursor may be applied to the conductor foil and baked to form an insulating film made of a polyimide film.
[0036]
In addition, the conductive layer 20 provided on the insulating film 11 is patterned as a wiring pattern 12 including the device side connection terminals 14, the input side external connection terminals 15, and the output side external connection terminals 16 by photolithography. That is, after applying a photoresist layer, the photoresist layer is removed by scientific dissolution (etching treatment) with an etching solution through a photomask, and further, the photoresist is dissolved and removed with an alkaline solution or the like. Pattern the body foil.
[0037]
Next, a solder resist material coating solution is applied on the wiring pattern 12 thus patterned by etching, and a solder resist layer 17 is formed by predetermined patterning.
[0038]
As the solder resist material coating solution, a curable resin is dissolved or dispersed in an organic solvent. As the curable resin, an epoxy resin, an epoxy-modified elastomer, a urethane resin, an elastomer-modified urethane resin , Polyimide resin, modified elastomer of polyimide resin, acrylic resin, and the like. In the coating solution, a curing accelerator, a filler, an additive, a thixotropic agent, and the like can be added. Further, in order to improve characteristics such as flexibility of the solder resist layer 17, fine particles having elasticity such as rubber fine particles can be blended. In addition, such a solder resist material coating solution is applied only to a necessary region by screen printing and thermally cured to become the solder resist layer 17.
[0039]
Further, a plating layer 21 is formed on the wiring pattern 12 that is not covered with the solder resist layer 17, that is, on the device-side connection terminal 14, the input-side external connection terminal 15, and the output-side external connection terminal 16. Examples of the plating layer 21 include tin, solder, gold, nickel-gold, and the like, and are selected according to the mounting method of the electronic component 30. For example, in this embodiment, the plating layer 21 is made of solder on the conductive layer 20. A plating layer 21 was formed.
[0040]
In the wiring pattern 12 provided on the insulating film 11, plating leads 12 a are formed on both sides of the insulating film 11 in the width direction over the input side external connection terminal 15 and the output side external connection terminal 16. It is patterned as follows.
[0041]
The plating leads 12 a provided on both sides in the width direction of the insulating film 11 are provided so as to conduct on the insulating film 11. In the present embodiment, for example, a conductive portion 12b is formed by patterning the conductive layer 20 between the respective wiring patterns 12, and the plated leads 12a on both sides are made conductive.
[0042]
Here, the electroplating apparatus of the present invention that applies the plating layer 21 on the wiring pattern 12, the device side connection terminal 14, the input side external connection terminal 15 and the output side external connection terminal 16 on the insulating film 11 will be described in detail. To do.
[0043]
3 is a schematic perspective view of the electroplating apparatus according to the first embodiment, FIG. 4 is a top view of the electroplating apparatus, and FIG. 5 is a sectional view taken along line BB ′ of FIG.
[0044]
As shown in FIGS. 3 to 5, the electroplating apparatus 40 of the present embodiment includes a plating tank 42 that holds a plating solution (solder plating solution) 41, and electrodes that are provided in the plating tank 42 and constitute an anode. 43.
[0045]
In addition, the plating tank 42 is continuously transported by a transport means (not shown) while the insulating film 11 on which the conductive layer 20 of the present embodiment is formed is immersed in the plating solution 41 in a standing state. Thus, it is comprised by the hook shape extended in a longitudinal direction with a substantially rectangular cross-sectional shape. That is, slit portions 44A and 44B are provided on the walls 41a and 41b on both sides in the longitudinal direction of the plating tank 42, respectively, and the insulating film 11 is provided with slit portions provided on one wall 41a in the longitudinal direction of the plating tank 42. It is conveyed from 44A across the longitudinal direction in the center in the width direction in the plating tank 42, and is conveyed to the outside of the plating tank 42 through a slit 44B provided on the other wall 41b.
[0046]
Further, the insulating film 11 conveyed while standing in the plating tank 42 is such that at least a part of the plating lead 12 a provided on one side in the width direction is exposed from the liquid surface of the plating solution 41. It has become. That is, in the present embodiment, the plating solution 41 is held in the plating tank 42 in an amount that is lower than the plating lead 12a of the insulating film 11, and the insulating film 11 inserted through one slit portion 44A has a predetermined amount. All the plating leads 12 a provided on one side in the width direction are exposed by immersing the other side in the width direction in the plating solution 41.
[0047]
The plating tank 42 is supplied with a new plating solution by a circulation device (not shown), and the height of the liquid level is always maintained at a fixed position.
[0048]
Further, in the plating tank 42, there is an electrode 43 constituting an anode (anode) at a predetermined distance so as to face one surface of the insulating film 11, that is, the surface provided with the wiring pattern 12 or the like. It is arranged. Note that the electrode 43 constituting the anode is connected to a power source (not shown).
[0049]
Further, the exposed plating lead 12a in the plating tank 42 is provided with a roll-shaped intermediate contact roll 45 as an intermediate cathode constituting a cathode (cathode) so as to contact the plating lead 12a.
[0050]
The intermediate contact roll 45 is provided in order to make the current density of the entire insulating film 11 substantially uniform. Depending on various conditions such as the length in the longitudinal direction of the plating tank 42 and the magnitude of the current, the intermediate contact roll 45 is provided. In this embodiment, two intermediate contact rolls 45 are provided.
[0051]
The intermediate contact roll 45 of the present embodiment is provided so that the pair of roll members 45a abuts the surface thereof and is not immersed in the plating solution 41, and the insulating film 11 is sandwiched between the surfaces of the pair of roll members 45a. This is in contact with the exposed plating lead 12a. That is, it is in contact with the plating lead 12 a in the vicinity of the lower end of the intermediate contact roll 45.
[0052]
Further, a pair of contact rolls 46 constituting a cathode (cathode) are provided outside the both ends in the longitudinal direction of the plating tank 42.
[0053]
Similarly to the intermediate contact roll 45, the contact roll 46 is also in contact with the plating lead 12a by bringing a pair of roll members 46a into contact with each other and sandwiching the insulating film 11 between the roll members 46a.
[0054]
The intermediate contact roll 45 and the pair of contact rolls 46 constituting such a cathode (cathode) are separately connected to a power source (not shown), and come into contact with the plating lead 12a of the insulating film 11 so that the plating lead 12a and the conductive portion are connected. The plated layer 21 is formed by supplying power to the wiring pattern 12 including the device side connection terminal 14, the input side external connection terminal 15, and the output side external connection terminal 16 through 12b.
[0055]
As described above, in this embodiment, at least a part of the plating lead 12a of the insulating film 11 is disposed so as to be exposed from the plating solution 41, and the intermediate contact roll 45 and the plating tank 42 that are in contact with the exposed plating lead 12a. Since electric power is supplied to the wiring pattern 12 by a cathode (cathode) composed of normal contact rolls 46 at both ends in the longitudinal direction, the difference in electrical resistance between the central portion of the wiring pattern 12 and both ends thereof is reduced and constant. The above current density can be ensured. Therefore, the distance between the power supply facilities can be set freely, and the electrical resistances of the wiring pattern 12, the plating lead 12a, and the conduction portion 12b can be reduced as much as necessary. Thus, even if the plating tank 42 is lengthened to widen the region where the plating layer 21 is formed, it is not necessary to increase the current, and high-speed electroplating can be continuously performed without forming a burned plating.
[0056]
In this embodiment, by adjusting the amount of the plating solution 41 and adjusting the liquid level, the entire plating lead 12a in the width direction is exposed, but the plating lead 12a of the insulating film 11 is one of them. If the part is exposed from the liquid surface of the plating solution 41, the present invention is not limited to this. Such an example is shown in FIG. FIG. 6 is a longitudinal sectional view of a plating tank showing a modification of the electroplating apparatus of the present embodiment.
[0057]
As shown in FIG. 6, the insulating film 11 conveyed into the electroplating apparatus 40 </ b> A is conveyed so that the substantially central portion immersed in the plating solution 41 is curved upward in the width direction. A predetermined amount is exposed from the surface of the plating solution 41 so that the central portion contacts the intermediate contact roll 45.
[0058]
In order to bend the insulating film 11 in order to expose a part of the plating lead 12a from the liquid surface, for example, a protrusion that fits into the sprocket hole 13 of the insulating film 11 is provided on the surface of the intermediate contact roll 45. Then, the insulating film 11 can be bent to expose a part of the plating lead 12a from the surface of the plating solution 41, and the contact between the plating lead 12a of the insulating film 11 and the intermediate contact roll 45 can be continued. It can be done reliably.
[0059]
Thus, it is not necessary to expose all the plating leads 12a, and the above-described effects can be obtained if a part of the plating leads 12a that are in contact with the intermediate contact roll 45 is exposed from the surface of the plating solution 41.
[0060]
Further, on the solder resist layer 17 of the insulating film 11 in which the wiring pattern 12, the device side connection terminal 14, the input side external connection terminal 15, the output side external connection terminal 16 and the solder resist layer 17 are thus formed, Specifically, an adhesive layer 31 for temporarily fixing an electronic component is provided. The adhesive layer 31 is preferably formed using a thermosetting and elastic adhesive, and may be formed by directly applying onto the solder resist layer 17, or using an adhesive tape. It may be formed. Further, the adhesive layer 31 does not need to be provided in the entire region where the electronic component is mounted, and may be provided in a partial region. However, the adhesive layer 31 is not always necessary.
[0061]
An electronic component 30 such as an IC is mounted as an electronic component on the solder resist layer 17 of the insulating film 11 through the adhesive layer 31. The electrodes 32 of the electronic component 30 and the device side connection terminals 14 of the wiring pattern 12 are connected via bumps 33 made of, for example, gold (Au).
[0062]
Such a film carrier tape 10 is cut for each wiring pattern 12 after the electronic component 30 is mounted, and when the electronic component 30 is mounted after being cut for each wiring pattern 12. There is.
[0063]
The film carrier tape 10 cut for each wiring pattern 12 is then connected to a driving element such as a piezo element as shown in FIG. 16 is connected to a circuit board or the like. In the present embodiment, the plating layer 21 made of solder is formed on the device-side connection terminal 14, the input-side external connection terminal 15, and the output-side external connection terminal 16 by the electroplating apparatus. The connection terminals 14 to 16 can be easily and reliably connected to the drive element or the circuit board.
[0064]
In this embodiment, all or part of the plating lead 12a is exposed from the plating solution 41 so as to come into contact with the intermediate contact roll 45. However, the present invention is not limited to this. The amount of the insulating film 11 up to substantially the middle in the width direction may be divided into two steps in which the insulating film 11 is inverted and plated on the other side in the width direction after plating is performed only on one side in the width direction. Thereby, the intermediate contact roll 45 can be reliably prevented from coming into contact with the plating solution 41.
[0065]
In the present embodiment, the TAB tape is exemplified as the film carrier tape for mounting electronic components. However, the present invention is not limited to this, and the electroplating apparatus and the plating method of the present invention are not limited to the T-BGA (Tape Ball Grid Array) tape. Needless to say, the present invention can be applied to various semiconductor packages such as a tape CSP (Chip Size Package) and an ASIC (Application Specific Integrated Circuit) tape.
[0066]
【The invention's effect】
As described above, in the present invention, an intermediate cathode that is provided so as not to be immersed in the plating solution and is in contact with a part of the conductive layer on the insulating layer is provided above at least the central portion in the longitudinal direction of the plating tank. Since the power is supplied by the intermediate cathode and the intermediate cathode, the difference in electrical resistance between the central portion of the conductive layer immersed in the plating solution and both ends thereof can be reduced, and a current density of a certain level or more can be ensured. For this reason, the distance between the power supply facilities can be set freely, and the electrical resistance of the conductive layer can be reduced as much as necessary. Thus, even if the plating tank is lengthened to widen the region for forming the plating layer, it is not necessary to increase the current, and high-speed electroplating can be continuously performed without forming the burned plating.
[Brief description of the drawings]
FIG. 1 is a plan view showing a schematic configuration of a film carrier tape for mounting electronic components according to Embodiment 1 of the present invention.
2 is a cross-sectional view of a film carrier tape for mounting electronic components according to Embodiment 1 of the present invention, and is a cross-sectional view taken along line AA ′ of FIG.
FIG. 3 is a schematic perspective view of an electroplating apparatus according to an embodiment of the present invention.
FIG. 4 is a top view of an electroplating apparatus according to an embodiment of the present invention.
5 is a cross-sectional view of an electroplating apparatus according to an embodiment of the present invention, and is a cross-sectional view taken along the line BB ′ of FIG.
FIG. 6 is a cross-sectional view showing a modification of the electroplating apparatus according to one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electronic component mounting board 11 Insulation film 12 Wiring pattern 12a Plating lead 12b Conductive part 13 Sprocket hole 14 Device side connection terminal 15 Input side external connection terminal 16 Output side external connection terminal 17 Solder resist layer 20 Conductive layer 21 Plating layer 30 Electron Component 31 Adhesive layer 40, 40A Electroplating device 41 Plating solution 42 Plating tank 43 Electrodes 44A, 44B Slit portion 45 Intermediate contact roll 45a Roll member 46 Contact roll 46a Roll member

Claims (8)

Plating is applied to the conductive layer while being transported along the longitudinal direction of the plating tank in a state where a continuous insulating film having a wiring pattern made of a conductive layer on the surface is immersed in a plating solution held in the plating tank. In the electroplating device to be a film carrier tape for mounting electronic components,
An anode provided in the plating tank and arranged to face the surface of the insulating film at a predetermined interval, and the conductive layer provided on the insulating film provided on both outer sides in the longitudinal direction of the plating tank A pair of cathodes for contacting and supplying power, and at least a central portion in the longitudinal direction of the plating tank so as not to be immersed in the plating solution and contacting a part of the conductive layer exposed from the plating solution And an intermediate cathode for supplying electric power. 2. The plating film according to claim 1, wherein a plating lead is formed by the conductive layer along a width direction end portion of the insulating film continuously to the wiring pattern, and the intermediate cathode is provided so as to contact the plating lead. An electroplating apparatus characterized by comprising: 3. The electroplating apparatus according to claim 2, wherein the insulating film is conveyed so that a part of the plating lead is exposed from the surface of the plating solution at least at a central portion in the longitudinal direction of the plating tank. . 3. The electroplating apparatus according to claim 1, wherein a plurality of the intermediate cathodes are provided at a predetermined interval. 5. The electroplating apparatus according to claim 1, wherein the intermediate cathode is a contact roll provided rotatably. A cathode in contact with an anode provided in the plating tank and a conductive layer immersed in the plating liquid by immersing a continuous insulating film having a wiring pattern made of a conductive layer on the surface in a plating liquid held in a plating tank In the plating method in which the conductive layer is plated while being conveyed along the longitudinal direction of the plating tank in a state where a voltage is applied between and the film carrier tape for mounting an electronic component,
In addition to the cathode provided outside the both ends in the longitudinal direction of the plating tank, an intermediate cathode that contacts the conductive layer is provided at least near the center in the longitudinal direction of the plating tank to supply power. And electroplating method. 7. The insulating film according to claim 6, wherein a plating lead is formed of the conductive layer along the width direction end portion continuously with the wiring pattern, and power is supplied so that the intermediate cathode is in contact with the plating lead. An electroplating method characterized by the above. 8. The electroplating method according to claim 7, wherein the insulating film is transported so that the plating lead provided at an end portion in the width direction of the insulating film is exposed at least at a center portion in a longitudinal direction of the plating tank. .

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