JP5652587B2 - Method for producing copper-coated polyimide substrate and electroplating apparatus - Google Patents

Description

  The present invention relates to a method for producing a copper-coated polyimide substrate for producing a flexible wiring substrate and an electroplating apparatus used for producing a copper-coated polyimide substrate. More specifically, the present invention relates to a method for producing a copper-coated polyimide substrate having a uniform copper thickness distribution.

  As an example of a flexible wiring board, COF (Chip on Film) has attracted attention as a technique for mounting a driver IC chip for displaying a liquid crystal screen. This COF is capable of fine pitch mounting as compared with TCP (Tape Carrier Package), which is a conventional mounting method, and is an easy mounting method for reducing the size and cost of the driver IC chip.

  Generally, a copper-coated polyimide substrate obtained by bonding a polyimide film that is a high heat resistance and high insulating resin and a metal layer that is a conductor is used for COF. This COF substrate is used for mounting by forming a fine wiring pattern on a metal layer of a copper-coated polyimide substrate by a subtractive method using a photolithography method, and further covering a desired portion with tin plating and a solder resist. Is.

  Here, in the case of producing a flexible wiring board by the subtractive method, first, a resist layer is provided on the surface of the metal layer of the base material, and a mask having a predetermined wiring pattern is provided on the resist layer. Exposure is performed by irradiating ultraviolet rays from above, and development is performed to obtain an etching mask for etching the metal layer. Then, the exposed metal portion is removed by etching, and then the remaining resist layer is removed and washed with water. If necessary, it is produced by applying predetermined plating to the lead terminal portion of the wiring.

As a method for forming a metal layer on the surface of the polyimide film, there are a manufacturing method of a three-layer substrate in which a polyimide film and an electrolytic copper foil or the like are bonded with an adhesive, and a metalizing method. The metallizing method is described below.
First, a metal layer such as a nickel-chromium alloy is formed by a dry plating method, and subsequently a metal layer such as copper is formed by a dry plating method in order to impart good conductivity. A stack of a metal layer such as a nickel-chromium alloy and a metal layer such as copper is referred to as a seed layer. Furthermore, the thickness of the metal layer is increased by using an electroplating method on the surface of the seed layer or by using an electroless plating method and an electroplating method together to form a metal layer having a desired thickness. The copper-coated polyimide substrate produced by this metallizing method is less affected by the adhesive than the three-layer substrate, and it is possible to obtain a copper-coated polyimide substrate utilizing the original characteristics of polyimide including high-temperature stability. It has the advantage of being able to.

  When copper is selected for the metal layer formed on the surface of the seed layer, an electroplating method is usually used, and a soluble phosphorus-containing copper ball is used for the anode (see Patent Document 1). By dissolving the phosphorus-containing copper balls of the anode, copper ions are supplied into the plating solution. At that time, impurities in the phosphorus-containing copper balls diffuse into the plating solution as a residue called anode slime, and contaminate the plating solution. It is believed that these contaminants adhere to the plating substrate, thereby causing unevenness on the surface of the plating film, that is, generation of plating nodules due to anode slime. If unevenness exists on the surface of the plating film, disconnection occurs at the time of wiring processing or mounting, which is a factor of greatly reducing reliability.

On the other hand, as a plating method that does not generate anode slime in principle, a method using an insoluble anode has been proposed.
This insoluble anode has been used for a long time in the process of electrolytically collecting excess metals and impurities in metal smelting and the like (see Patent Document 2).

  In recent years, this method using insoluble anodes has been used to solve problems caused by anode slime in the electroplating process. As an alternative to soluble metal anodes, it is insoluble in the anode chamber separated from the plating solution by an ion exchange membrane. When a copper anode is installed and a copper plating process is performed, a dedicated tank filled with copper oxide is installed as a copper ion source, and the plating tank and the plating solution in this tank are circulated in the plating solution. A plating method for controlling the copper ion concentration is disclosed (see Patent Document 3).

Japanese Patent Laid-Open No. 2000-256891 Japanese Patent Laid-Open No. 10-60678 JP 2004-269955 A

  As described above, the copper electroplating method using the insoluble anode is greatly effective in suppressing disconnection during wiring processing and mounting due to generation of anode slime in the conventional copper electroplating method using the soluble anode. Although contributing, in addition to improving quality during manufacturing, it is required to make the film thickness distribution of the copper plating layer more uniform by making finer pitch wiring and expanding the use of copper-coated polyimide substrates. At present, the effect is not sufficient, and a method for uniformly plating the film thickness distribution of the copper plating film layer is desired.

  Under such circumstances, the present invention provides a method for producing a copper-coated polyimide substrate having a good copper thickness distribution in view of the above-mentioned problems of the prior art, and improves the uniformity of the copper thickness distribution of the copper-coated polyimide substrate. It is to improve.

  In order to solve such problems, as a result of intensive studies on a method for producing a copper-coated polyimide substrate having a good copper thickness distribution, an insoluble anode was used in the electroplating process, and the current in a specific region of the anode It has been found that when a copper layer is plated while shielding, a target copper thickness distribution can be achieved.

In the first aspect of the present invention, a long polyimide film with a seed layer in which a conductive seed layer is formed on at least one side of a long polyimide film by a dry plating method is conveyed so that the width direction is substantially horizontal. , using multiple electroplating method or an electroless plating method and the multiple insoluble anode by control for increasing stepwise the current density with respect to the transport direction using the insoluble anode to the surface of the seed layer A method for producing a copper-coated polyimide substrate, in which a copper plating film layer is formed using a wet plating method selected from a combination of electroplating methods by controlling the current density to be increased stepwise in the conveying direction. The insoluble anode in which the current density of the current applied among the plurality of insoluble anodes is 35 mA / cm ² or more is at least 40 cm from the upper end to the lower end of the insoluble anode. Then, it has an anode width of 80% to 90% of the copper plating film layer width of the copper-coated polyimide substrate, and the current density of the current applied among the plurality of insoluble anodes is less than 35 mA / cm ^2. The insoluble anode has an anode width exceeding 90% of the copper-plated coating layer width of the copper-coated polyimide substrate from the upper end to the lower end of the insoluble anode , and more than The insoluble anode is electrically divided into two or more groups in the transport direction, and each divided insoluble anode has a current density controlled independently for each group. Is.

According to a second aspect of the present invention, a long polyimide film with a seed layer in which a conductive seed layer is formed on at least one side of a long polyimide film by a dry plating method is conveyed so that the width direction is substantially horizontal. an electric plating method or an electroless plating method by control for increasing stepwise the current density with respect to the transport direction insoluble anode of several on the surface of the seed layer, the insoluble anodes of multiple use An electroplating apparatus for a copper-coated polyimide substrate for forming a copper plating film layer selected from a combination of electroplating methods by controlling the current density to increase in a stepwise manner with respect to the transport direction, the plurality of insoluble The insoluble anode having a current density of 35 mA / cm ² or more due to the current applied in the conductive anode, is at least 40 cm from the upper end to the lower end of the copper-coated polyimide substrate. An insoluble anode having an anode width of 80% to 90% of the copper plating film layer width, and a current density of a current applied among the plurality of insoluble anodes is less than 35 mA / cm ² , From the upper end to the lower end of the insoluble anode, the anode width is more than 90% of the copper plating film layer width of the copper-coated polyimide substrate .

In addition, an insoluble anode having a current density of 35 mA / cm ² or more due to an electric current applied among a plurality of insoluble anodes is formed by a shielding plate arranged so as to cover the surface of the insoluble anode. The width is 80% to 90% of the width of the copper plating film layer.

  Furthermore, the plurality of insoluble anodes are electrically divided into two or more groups in the transport direction, and the insoluble anodes divided into two or more groups are independently controlled in current density for each group. The plurality of insoluble anodes are metal anodes using platinum or lead, or at least one conductive material selected from iridium oxide, rhodium oxide, and ruthenium oxide on a titanium frame. It is characterized by being a ceramic anode coated with a ceramic film having sinter.

  According to the present invention, it is possible to obtain a copper-coated polyimide substrate having high processing accuracy and useful for fine pitch. More specifically, the copper-coated polyimide substrate of the present invention can improve processing accuracy due to a uniform copper thickness distribution. Specifically, the difference between the maximum value and the minimum value of the copper layer thickness within the range of 470 mm can be suppressed within 0.5 μm, which is suitable for fine pitch COF with a pitch of 30 μm or less, and industrial value. Is extremely large.

It is a flowchart which shows the general manufacturing process of a copper covering polyimide substrate. It is sectional drawing of the copper covering polyimide substrate manufactured using the manufacturing method of this invention, (a) is a board | substrate provided with the copper layer which consists only of the copper plating film layer by an electroplating method, (b) is by an electroless plating method It is a board | substrate provided with the copper layer which consists of a copper thin film layer and the copper plating film layer by an electroplating method. It is the schematic seen from the side of the electroplating apparatus used for the manufacturing method of the copper covering polyimide substrate of this invention. It is the schematic which showed in detail the arrangement | positioning of the anode 14g and the anode 14h among the electroplating cells of the electroplating apparatus 1. FIG. It is the schematic of the anode 14g which shows an example of the anode divided | segmented into the conveyance direction of the long polyimide film 20a with a seed layer.

FIG. 1 shows a general manufacturing process of a copper-coated polyimide substrate.
The copper-coated polyimide substrate is produced by subjecting a raw material polyimide film to sputtering treatment and electroplating treatment to form a desired metal film. The copper-coated polyimide substrate manufactured by this method does not require an adhesive, so it can utilize the inherent characteristics of polyimide such as high heat resistance and high insulation, and can be folded and used during mounting. Therefore, it can greatly contribute to miniaturization of devices. Details of each step will be described below.

(1) Copper-coated polyimide substrate FIG. 2 is a cross-sectional view of a copper-coated polyimide substrate produced using the production method of the present invention. A base metal layer 3 such as a nickel-chromium alloy, a copper thin film layer 4 and a copper plating film layer 5 are laminated on the surface of the polyimide film 2. A laminate of the base metal layer 3 and the copper thin film layer 4 is referred to as a seed layer 6. Further, the copper plating film layer 5 may be formed by using only the copper electroplating method (see FIG. 2A), or by the copper electroless plating method and then the copper electroplating method. Good (see FIG. 2B).

  The copper-coated polyimide substrate 10 of the present invention forms a copper layer on the surface of the polyimide film 2, and first, a base metal layer 3 such as a nickel-chromium alloy is formed by a sputtering method. The thickness of the base metal layer 3 is not particularly limited, but is generally 5 to 50 nm. Subsequently, in order to give good conductivity to the surface of the base metal layer 3, the copper thin film layer 4 is subsequently formed by a sputtering method of a dry plating method. The thickness of the copper thin film layer 4 formed by this process is generally 50 to 500 nm.

  Further, a film is formed on the surface of the seed layer 6, that is, the surface of the copper thin film layer 4 by a wet plating method. Referring to FIG. 2 a, a copper plating film layer 5 using an electroplating method which is a kind of wet plating method is formed on the surface of the copper thin film layer 4, and the copper comprising the copper thin film layer 4 and the copper plating film layer 5. A layer is provided. Further, in FIG. 2b, the surface of the copper thin film layer 4 is combined with a kind of electroless plating method and electroplating method of the wet plating method, and the copper electroless plating layer 5a by the electroless plating method and copper by the electroplating method. The plated coating layer 5 is formed, and a copper layer comprising the copper thin film layer 4, the copper electroless plated layer 5a, and the copper plated coating layer 5 is provided to have a desired film thickness. When the electroless plating method and the electroplating method are used in combination, copper is formed on the surface of the seed layer by electroless plating, and then electroplating is performed on the surface of the film formed by electroless plating.

  The thickness of the copper layer is generally 5 to 18 μm, for example, when a circuit pattern is formed by a subtractive method. In addition, when using an electroplating method for formation of a copper layer, the formation is performed using the acidic plating solution which has a sulfuric acid and copper sulfate as a main component.

(2) Electroplating apparatus FIG. 3: is the schematic seen from the side of the electroplating apparatus used for the manufacturing method of the copper covering polyimide substrate of this invention. In FIG. 3, 1 is an electroplating apparatus, 11 is a plating bath, 12 is an unwinding shaft, 13 is a driven roll, 14a to 14h are insoluble anodes (hereinafter referred to as anodes), 15 is a winding shaft, and 16a. -16e is a feed roll, and 20a and 20b are long polyimide films with a seed layer.

  In the electroplating apparatus shown in FIG. 3, the plating bath 11 is filled with an acidic plating solution mainly composed of sulfuric acid and copper sulfate. The long polyimide film 20a with the seed layer is transported with the width direction being substantially horizontal, unwound from the unwinding shaft 12, and transported so as to be immersed in the plating solution in the plating solution tank 11 by the power supply roll 16a. The conveying direction can be changed to the plating solution surface direction of the plating solution tank 11 by the driven roll 13 in the plating solution tank 11. Further, the feeding roll 16b, the driven roll 13, the feeding roll 16c, the driven roll 13, the feeding roll 16d, the driven roll 13, and the feeding roll 16e are conveyed in this order, so that the immersion in the plating solution is repeated. Eventually, the long polyimide film 20b with a seed layer (in this state, electroplating is completed and thus becomes a copper-coated polyimide substrate) is taken up by the take-up shaft 15.

  Here, the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g and 14h constitute an electrically independent electroplating cell. Therefore, when the surface of the metal film (for example, a copper thin film layer) of the long polyimide film 20a with the seed layer is in contact with the power supply rolls 16a, 16b, 16c, 16d, 16e, the anodes 14a, 14b, 14c, 14d, A potential difference is generated between 14e, 14f, 14g, and 14h, and electroplating is performed.

  The anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are connected to positive electrodes of control power sources (also referred to as rectifiers, not shown) that are electrically independent of each other. The negative electrode of this control power source is connected to the power supply rolls 16a, 16b, 16c, 16d, and 16e. That is, the anode 14a constitutes an electroplating circuit by the control power source connected to the anode 14a, the feeding roll 16a, and the long polyimide film 20a with a seed layer. Similarly, the anodes 14b, 14c, 14d, 14e, 14f, 14g, and 14h constitute an electroplating circuit.

Furthermore, the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are controlled in current density by a control power source connected to each anode so that the current density increases stepwise from the unwinding shaft 12 side. Has been made. The control for increasing the current density in stages is appropriately determined in consideration of the film thickness of the copper plating film layer.
Further, the electroplating apparatus 1 includes various known apparatuses used for transporting a long polyimide (resin) film such as a control roll for controlling the tension of the long polyimide film 20a with a seed layer, and stirring and supply of a plating solution. It is also possible to add various known devices such as.

(3) Anode FIG. 4 is a schematic diagram showing the arrangement of the anode 14g and the anode 14h in the electroplating cell of the electroplating apparatus 1 in more detail. The anode 14g and the anode 14h are divided into two groups in the transport direction of the long polyimide film 20a with a seed layer. In FIG. 4, the anode 14g is divided into an upper anode 14g-1 and a lower anode 14g-2, and is installed on the frame 21g. The upper end of the upper anode 14g-1 is below the plating solution surface 11b, and the entire anode 14g is immersed in the plating solution.

Furthermore, an anode to which a current density of 35 mA / cm ² or more is applied has an anode width of 80 to 90% of the copper plating film layer width. More preferably, by using the divided anode as shown in FIG. 4, the current density distribution becomes more uniform, and a more uniform copper thickness distribution can be obtained.

That is, when the current density is increased, the deposition rate of the copper plating film is increased, while the current is concentrated in a portion where the current easily flows, and the current density becomes non-uniform. If the current density becomes uneven, as a result, the film thickness distribution of the copper plating film layer becomes wide. In particular, the current concentrates on the end portion of the copper plating film layer, which increases the film thickness and widens the film thickness distribution. As a result, the film thickness distribution of the copper layer composed of the copper thin film layer 4 and the copper plating film layer 5 is widened.
Therefore, this state can be avoided by setting the width of the anode to which a current density of 35 mA / cm ² or more is applied to 80 to 90% of the copper plating film layer width.
In addition, if the width of the anode applied with a current density of less than 35 mA / cm ² is 80 to 90% of the width of the copper plating film layer, the film thickness distribution of the copper plating film layer having a desired film thickness will not increase. However, there is a problem that the film thickness at both ends in the width direction of the copper plating film layer becomes thin, and the width of the copper plating film layer having a desired film thickness becomes narrow.

As shown in FIG. 4, the anode width is adjusted by providing shielding plates 17g and 17h between the anodes 14g and 14h, which are insoluble anodes, and the long polyimide film 20a with a seed layer. May be adjusted so as to be 80 to 90% of the width of the copper plating film layer, or an anode whose width is itself 80 to 90% of the width of the copper plating film layer may be used.
In particular, when a shielding plate is used, the anode width can be easily adjusted. Further, the shielding plate may be placed in parallel with the anode as shown in FIG. 4 or may be installed in an eight-letter shape when viewed from the side where the lower side spreads.
As the shielding plate used for adjusting the anode width, a known electrically insulating plastic or ceramic is used.

  Further, the width of the anode is adjusted so as to be 80 to 90% of the width of the copper plating film layer from the upper end to the lower end of the anode. Here, when the anode is not completely immersed in the plating solution, the width of the anode is at least 80 to 90% of the copper plating film layer width from the position of the plating solution surface to the position of 40 cm in the lower end direction.

  The anode width is adjusted from the upper end to the lower end of the anode to at least 40 cm because the current density is higher near the plating solution surface and the film thickness distribution of the copper plating film layer is larger. It is adjusted to suppress the condition. In addition, you may be an anode of 80 to 90% of width | variety of a copper plating film layer width from an upper end to a lower end.

Furthermore, it is desirable that the anode is electrically divided in the transport direction.
FIG. 5 is a schematic view of an anode 14g showing an example of the anode divided in the conveyance direction of the long polyimide film 20a with a seed layer.
The anode 14g is composed of an upper anode 14g-1 and a lower anode 14g-2 provided in a frame 21g having electrical insulation. The upper anode 14g-1 is electrically connected to the bus bar 24g-1, and the lower anode 14g-2 is electrically connected to the bus bar 24g-2. Since the bus bar 24g-2 passes through the back surface of the frame 21g, it does not come into contact with the upper anode 14g-1. The bus bars 24g-1 and 24g-2 are placed on the edge of the plating bath, and the anode 14g is disposed through the frame 21g. Therefore, the anode 14g can be attached to and detached from the electroplating apparatus 1 freely. ing. The bus bars 24g-1 and 24g-2 are connected to independent control power sources.

  Note that electrically dividing means that there is no electrical connection between the divided anodes. The anode 14g in FIG. 5 will be described as an example. The upper anode 14g-1 and the lower anode 14g-2 are arranged on the frame 21g having electrical insulation so that there is no electrical contact. That is, in the electroplating cell of the electroplating apparatus 1 of FIG. 3, the anode is electrically divided vertically in the depth direction of the plating solution.

In this way, it is desirable to electrically divide the anodes in the conveying direction, by connecting individual control circuits to each divided anode and controlling the current for each divided anode. This is because the thickness can be made uniform, and the film thickness distribution of the copper plating film layer can be made more uniform.
The material of the frame 21g may be selected from materials that can maintain electrical insulation even in the plating solution and is not eroded by the plating solution, and a known plastic or ceramic having electrical insulation may be used.

  In the present invention, an insoluble anode is used as the anode. When this insoluble anode is used, it is possible to obtain a copper-coated polyimide substrate having a good thickness distribution of the copper-plated coating layer as compared with a copper-coated polyimide substrate produced using a soluble phosphorous copper-containing anode. .

  In general, a soluble anode is a titanium basket filled with phosphorus-containing copper balls, and copper ions are supplied into the plating solution by dissolving the phosphorus-containing copper balls. When the shape of a soluble anode changes with time due to dissolution, the current density distribution of the cathode also changes with time. In addition, since the electrical contact area between the balls is reduced by adsorbing organic components such as additives on the surface of the phosphorus-containing copper balls, the electrical resistance of the whole anode is increased.

  On the other hand, the insoluble anode can have a structure in which the change with time of the shape is uniform in the depth direction and the width direction in principle. In addition, it has a lower electrical resistance than a soluble anode, it is easy to obtain a uniform current density distribution in the depth direction and width direction, and a copper-coated polyimide substrate having a uniform film thickness and a narrow film thickness distribution is obtained. Is possible.

  Preferable examples of insoluble anodes include metal anodes such as platinum and lead, and ceramic anodes that are coated by firing a conductive ceramic such as iridium oxide, rhodium oxide, or ruthenium oxide on a titanium frame. Can be used for Preferably, a ceramic insoluble anode in which a titanium frame is coated with iridium oxide and rhodium oxide is employed. Since this insoluble anode uses ceramics, it is relatively stable even in a copper sulfate plating solution, and has an advantage that even when deteriorated, it can be regenerated by firing again.

  When such an insoluble anode is used, an electrolysis reaction of water occurs on the anode during the electroplating process, and oxygen gas is generated accordingly. When oxygen gas is generated, the additives in the plating solution are abnormally consumed, and when the gas is generated vigorously, the anode itself deteriorates. At the same time, the generation of oxygen gas is suppressed. In addition, the generation of oxygen gas is reduced by adding iron ions to the plating solution.

  Therefore, the concentration of iron added to the plating solution is preferably 0.1 to 10 g / L. If the iron concentration is less than 0.1 g / L, the effect of reducing the generation of oxygen gas is not sufficient, and if it exceeds 10 g / L, the current efficiency in the electroplating process is significantly reduced, which is not preferable. Electrochemically, the oxidation reaction of iron ions takes place on the anode in preference to the electrolysis reaction of water, so that the generation of oxygen gas can be suppressed.

  In the present invention, copper oxide, copper carbonate, oxygen-free copper, and the like are suitably used as the copper ion supply source when using the insoluble anode. In particular, oxygen-free copper that is easily dissolved by trivalent iron ions added to the plating solution is preferable.

  The present invention will be described in more detail using examples.

  Kapton 150EN (thickness 38 μm) manufactured by Toray DuPont is used for the long polyimide film, and this polyimide film is subjected to heat treatment at 150 ° C. for 1 minute in a chamber maintained at a vacuum degree of 0.01 to 0.1 Pa. gave. Subsequently, a 7 nm thick nickel-chromium alloy layer containing 7% by weight of chromium was formed on this polyimide film by sputtering, and a copper layer was further formed to a thickness of 100 nm to obtain a long polyimide film F with a seed layer. For sputtering, a roll-to-roll type sputtering apparatus was used.

After sputtering, a copper layer was formed to a thickness of 8 μm by electroplating using the electroplating apparatus 1 of FIG. The basic composition of this plating solution is a sulfuric acid concentration of 180 g / L, a copper sulfate concentration of 80 g / L, and a chlorine concentration of 50 mg / L, and an organic additive for the purpose of ensuring the smoothness of the copper plating film. Was added in a predetermined amount.
The anode used in the electroplating process was not divided, and the material used was an electrode of Permerek Electrode Co., Ltd., which is an iridium oxide-based insoluble anode. Further, an oxygen-free copper ball was adopted as a copper ion supply source, and the iron ion concentration in the plating solution was 7.0 g / L.

Table 1 shows the current density applied to each anode.
Further, both ends of the anodes 14f, 14g, and 14h are shielded by an insulating shielding plate, and adjusted so that the anode has a width of 90% of the width of the copper plating film layer, thereby producing a copper-coated polyimide substrate. The thickness distribution was evaluated.

  The measurement of the film thickness distribution is shown in Table 2 by measuring the copper thickness distribution of a 470 mm copper-coated polyimide substrate in the width direction using a fluorescent X-ray film thickness meter and calculating the difference between the maximum value and the minimum value.

  A copper-coated polyimide substrate was prepared under the same conditions as in Example 1 except that the widths of the anodes 14f, 14g, and 14h were adjusted to be 80% of the width of the copper plating film layer, and the film thickness distribution was evaluated. did. The results are shown in Table 2.

The anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are electrically divided anodes as shown in FIG. 4, and only the upper anodes of the anodes 14f, 14g, and 14h are copper-plated. It was adjusted to be 90% of the coating layer width, and each of the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h was provided with an independent control power source for each of the upper and lower anodes, and the current density was adjusted. Except for the controlled point, a copper-coated polyimide substrate was produced under the same conditions as in Example 1, and the film thickness distribution was evaluated. The results are shown in Table 2.
The lengths of the upper and lower anodes of the anodes 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h, that is, the length in the transport direction of the long polyimide film 20a with a seed layer were set to 70 cm.

(Comparative Example 1)
A copper-coated polyimide substrate was prepared under the same conditions as in Example 1 except that the anode was not shielded, and the film thickness distribution was evaluated. The results are shown in Table 2.

(Comparative Example 2)
A copper-coated polyimide substrate was prepared under the same conditions as in Example 3 except that the anode was not shielded, and the film thickness distribution was evaluated. The results are shown in Table 2.

(Comparative Example 3)
A copper-coated polyimide substrate was prepared under the same conditions as in Example 1 except that the shielding with respect to the anode was set to 70%, and the film thickness distribution was evaluated. The results are shown in Table 2.

(Comparative Example 4)
Copper-coated polyimide under the same conditions as in Example 1, except that a soluble anode (Mitsubishi Materials, phosphorus-deoxygenated copper) was used as the anode in the electroplating process, and that iron ions were not added to the plating solution. A substrate was prototyped and the film thickness distribution was evaluated.
The results are shown in Table 2.

(Comparative Example 5)
A copper-coated polyimide substrate was prepared under the same conditions as in Example 3 except that the shielding against the anode was shielded by 35 cm from the plating solution surface, and the film thickness distribution was evaluated. The results are shown in Table 2.

(Comparative Example 6)
A copper-coated polyimide substrate was prepared under the same conditions as in Example 2 except that 80% of shielding against the anode 14e having a current density of less than 35 mA / cm ² was added, and the film thickness distribution was evaluated. The results are shown in Table 2.
In Examples 1 to 3 and Comparative Examples 1 to 5, the film thickness of the copper layer is 8 μm in the width direction of 470 mm. In Comparative Example 6 , when the film thickness is measured in the width direction of 470 mm, 10 mm at both ends of the width. In this case, the film thickness of the copper layer could not be secured 8 μm. Therefore, Table 2 shows the measurement results of the film thickness distribution in the width direction of 450 mm.

As is clear from Tables 1 and 2, in Examples 1, 2, and 3 in which the manufacturing method of the present invention was implemented, the difference between the maximum value and the minimum value of the copper layer thickness can be suppressed to within 0.4 μm. On the other hand, it can be seen that Comparative Examples 1 to 5 cannot be suppressed to within 0.5 μm.
Further, as shown in Comparative Example 6 , when the shielding is excessively performed even to the anode having a low current density, a uniform copper layer cannot be obtained over the entire width.

DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 2 Polyimide film 3 Underlying metal layer 4 Copper thin film layer 5 Copper plating film layer 5a Copper electroless plating film layer 6 Seed layer 10 Copper coating polyimide substrate 11 Plating solution tank 11b Plating solution surface 12 Unwinding shaft 13 Driven roll 14a-14h Anode (insoluble anode)
14g-1, 14h-1 Upper anode 14g-2, 14h-2 Lower anode 15 Winding shafts 16a-16e Feed rolls 17a, 17b Shield plates 20a, 20b Long polyimide film with seed layer 21g, 21h Frame 24g-1, 24g-2 Busbar

Claims (7)

At least one surface width direction of the seed layer with long polyimide film a seed layer is formed of a conductive dry plating is conveyed approximately so horizontally, multiple on the surface of the seed layer of the long polyimide film insoluble anode stepwise with respect to the transport direction using the electroplating method or an electroless plating method and the multiple insoluble anode by control for increasing stepwise the current density with respect to the transport direction with the A method for producing a copper-coated polyimide substrate, in which a copper plating film layer is formed using a wet plating method selected from a combination of electroplating methods under control to increase current density,
The insoluble anode having a current density of 35 mA / cm ² or more applied between the plurality of insoluble anodes is at least 40 cm from the upper end to the lower end of the insoluble anode. , Having an anode width of 80% to 90% of the copper plating film layer width of the copper-coated polyimide substrate ,
The insoluble anode in which the current density of the current applied among the plurality of insoluble anodes is less than 35 mA / cm ² is at least 40 cm from the upper end to the lower end of the insoluble anode. A method for producing a copper-coated polyimide substrate, characterized by having an anode width exceeding 90% of the copper-plated coating layer width of the copper-coated polyimide substrate.   The plurality of insoluble anodes are electrically divided into two or more groups in the transport direction, and the divided insoluble anodes are controlled in current density independently for each group. The method for producing a copper-coated polyimide substrate according to claim 1. On at least one surface width direction of the seed layer with long polyimide film a seed layer is formed of a conductive dry plating is conveyed approximately so that the horizontal direction, the surface of the seed layer of the long polyimide film, double an electric plating or electroless plating by control for increasing stepwise current density insoluble anode having the conveying direction, stepwise with respect to the transport direction using the insoluble anode of the multiple An electroplating apparatus for a copper-coated polyimide substrate for forming a copper plating film layer selected from a combination of electroplating methods by controlling to increase current density,
Among the plurality of insoluble anodes, the insoluble anode having an applied current density of 35 mA / cm ² or more is at least up to a position of 40 cm from the upper end to the lower end of the insoluble anode. Has an anode width of 80% to 90% of the copper plating film layer width of the copper-coated polyimide substrate ,
The insoluble anode in which the current density of the current applied among the plurality of insoluble anodes is less than 35 mA / cm ² is at least 40 cm from the upper end to the lower end of the insoluble anode. An electroplating apparatus having an anode width exceeding 90% of a copper plating film layer width of the copper-coated polyimide substrate . Among the plurality of insoluble anodes, the insoluble anode having a current density of an applied current of 35 mA / cm ² or more is provided by the shielding plate disposed so as to cover the surface of the insoluble anode. 4. The electroplating apparatus according to claim 3, wherein the width of the insoluble anode is 80% to 90% of the width of the copper plating film layer.   The plurality of insoluble anodes are electrically divided into two or more groups in the transport direction, and the insoluble anodes divided into the two or more groups are independently controlled in current density for each group. The electroplating apparatus according to claim 3 or 4, wherein   The electroplating apparatus according to claim 3, wherein the plurality of insoluble anodes are metal anodes using platinum or lead.   The plurality of insoluble anodes are ceramic anodes obtained by coating a titanium frame with a ceramic film having at least one conductivity selected from iridium oxide, rhodium oxide, and ruthenium oxide by firing. Item 6. The electroplating apparatus according to any one of Items 3 to 5.

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