JP3340307B2 - Manufacturing method of copper foil for printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copper foil for a printed wiring board, and more particularly, to a method of depositing copper on a rotating cathode drum in an electrolytic cell supplied with an electrolytic solution containing copper ions. The present invention relates to a continuous electrolytic production method for continuously producing copper foil for a printed wiring board by detaching the copper foil from the cathode drum while rotating the cathode drum in an electrolytic cell.

[Prior art]

In recent years, multilayered printed wiring boards have been promoted, and accordingly, prevention of occurrence of foil cracks in copper foil for printed wiring boards has become a problem. From such a viewpoint, in particular, a copper foil having a high hot elongation at 180 ° C. (hereinafter, referred to as “hot elongation”) has been demanded. In order to increase the hot elongation, it has been conventionally proposed to add various additives to the electrolyte.

[0003] For example, JP-A-63-31089 and JP-A-63-310990 disclose that an additive obtained by combining triisoamylamine or hydroxyalkylamine with chloride and gelatin is added to an electrolytic solution. Has been described. Japanese Patent Publication No. 2-25995 discloses that a similar combination of triisopropanolamine and gelatin is used as an additive. JP-A-2-
182890 describes that a water-soluble cellulose ether is used as an additive liquid. Further, Japanese Unexamined Patent Publication No.
No. 278866 discloses a glue concentration of 0.55 ppm or less, a chloride ion of 20 to 100 ppm, and a sulfuric acid concentration of 20 to 100 ppm.
A method for obtaining a copper foil under the conditions of 200 g / l and an electrolyte temperature of 20 to 70 ° C., and Japanese Patent Application Laid-Open No. 7-278867 discloses that 0.1 μg / l to 250 mg / l tungsten or tungsten Each of the methods of adding compounds is described.

In such prior art, as described above, special additives are often used, which not only inevitably increases the cost, but also results in a plurality of additives such as amine and chloride and gelatin. , And the decomposition products of these additives accumulate, which complicates the management of the electrolyte. In addition, Japanese Patent Application Laid-Open No. 7-2
In the method described in Japanese Patent No. 78867, phosphorous acid, pyrophosphoric acid phosphate,
It is necessary to add any one of polyphosphoric acid, arsenous acid, and metavanadic acid, but all of these substances are poisons, and when added in large amounts, there are problems such as adversely affecting the physical properties of the copper foil. .

Further, as a copper foil for a printed wiring board,
Generally, as described above, a copper foil having a high hot elongation rate is desired, but a copper foil having an excessively high hot elongation rate tends to have a decreased tensile strength due to heat treatment in the processing step. Therefore, there is a demand for copper foils having different levels of hot elongation depending on applications. However, it is difficult to separately produce copper foils having different levels of hot elongation in the prior art, and the obtained copper foil has a large variation in hot elongation, which is a problem during processing.

[0006]

DISCLOSURE OF THE INVENTION In view of the above-mentioned various problems, the present invention makes it easy to separately form copper foils having different levels of hot elongation than the prior art, and furthermore, the variation in hot elongation is reduced. A main object is to propose a new manufacturing method capable of manufacturing a small electrolytic copper foil. In particular, the present invention does not require a special additive, and not only facilitates the concentration control of the additive, but also easily achieves an arbitrary hot elongation by adjusting the additive concentration. It is based on the idea of making it possible to reduce the variation of the hot elongation rate.

[0007]

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention provides an electrodeposition of copper on a rotating cathode drum in an electrolytic cell to which an electrolytic solution is supplied. In a continuous electrolysis method in which a foil is peeled from a cathode drum to produce a copper foil for a printed wiring board, an electrolytic solution supplied into an electrolytic cell is treated with activated carbon , and the amount of the additive added to the electrolytic replenisher after the activated carbon treatment is reduced. Control to the desired range of 180 ° C
The present invention proposes a method for producing a copper foil for a printed wiring board, wherein a copper foil having a hot elongation rate is obtained .

According to the present invention, the electrolytic solution supplied into the electrolytic cell is treated with activated carbon to completely remove the residual additive from the electrolytic solution, and then a predetermined amount of additive is newly added. It is possible to precisely control the additive concentration in the electrolytic replenisher to a desired value. Therefore, the physical properties of the copper foil can be easily controlled. In addition, it is possible to selectively produce copper foils having different levels of hot elongation by adjusting the amount of the additive.

In carrying out the method of the present invention, the activated carbon treatment is desirably performed at a superficial velocity of, for example, 30 cm / sec or less.

The additive to be added to the electrolytic replenishing solution after the activated carbon treatment is not particularly limited as long as it can be adsorbed and removed by activated carbon, and a plurality of additives can be combined. Therefore, general and special additives conventionally used for copper electrolysis may be used as long as they are easily adsorbed by activated carbon. For example, glucose, thiourea, glycine, polyvinyl chloride, polyethylene glycol, triglyceride, etc. Ethanolamine, hydrazine, vinyl acetate and the like can also be used as additives in the present invention. However, from a practical point of view, it is desirable to use glue or gelatin, which can be obtained relatively inexpensively, as an additive.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart showing an outline of an electrolytic facility for carrying out a conventional method, FIG. 2 is a similar flowchart showing an outline of an electrolytic facility for carrying out the method of the present invention, and FIG. 3 is gelatin as an additive. 4 is a graph showing the relationship between the concentration of copper and the hot elongation of the electrolytic copper foil. FIG. 4 is an explanatory view showing the state in which the residual additive and decomposition products are accumulated in each circulation cycle of the electrolytic solution by the conventional method, and FIG. FIG. 3 is an explanatory view showing a situation in which a residual additive and decomposition products are removed in each circulation cycle of an electrolytic solution by the method of the present invention.

1 and 2, reference numeral 1 denotes an electrolytic cell in which a cathode drum is rotatably arranged, 2 denotes a tail liquid tank,
3 is a dissolving tower, 4 and 4 'are replenisher tanks, 5 is an activated carbon tower, 6
Is an additive tank in which an aqueous additive solution adjusted to a predetermined concentration is stored. The symbol p represents a metering pump. In a continuous electrolysis facility for copper foil, electrolysis is performed while circulating an electrolytic solution containing copper ions and passing the solution between a cathode drum and an anode (not shown) facing the cathode drum. And the copper foil is peeled off from the cathode drum while the cathode drum is continuously rotated, and wound on the winding drum d.

In the prior art, as shown in FIG. 1, the additive in the additive tank 6 is continuously added to the replenishing liquid storage tank 4 by the metering pump p so that the concentration falls within a predetermined range. In this case, it goes without saying that the amount of the additive to be added should be equal to the amount of the additive consumed by spontaneous decomposition and electrolysis. However, since the amount of additive consumption due to spontaneous decomposition and the amount of additive consumption due to electrolysis cannot be accurately measured, it is managed based solely on the experience and intuition of the worker and the physical properties of the obtained copper foil. In reality, the concentration of the additive in the electrolytic replenishing solution is not constant, and as a result, problems such as an increase in the dispersion of the physical properties of the copper foil have become inevitable.

On the other hand, in the present invention, the activated carbon tower 5 is disposed downstream of the replenishing liquid storage tank 4 'so that the replenishing liquid storage tank 4'
After the old additive contained in the replenishing solution is adsorbed and removed by passing the replenishing solution inside the activated carbon tower 5, the required amount of additive is newly added and mixed by the metering pump p, and the replenished solution mixed is electrolyzed. Supply to tank 1. Therefore, the concentration of the additive in the replenishing solution can be easily controlled by the amount of the additive to be added and the flow rate of the electrolytic replenishing solution.

In the electrolytic facility shown in FIG. 2, the activated carbon treatment can be performed at a superficial velocity of, for example, 30 cm / sec or less. The additive solution may be directly injected into the outlet pipe of the activated carbon tower 5, and in this case, the replenisher tank 4 'can be omitted.

According to the present invention, the physical properties of the copper foil can be easily controlled by controlling the additive concentration in the electrolytic replenisher. As described above, as an additive, an organic substance which can be easily adsorbed and removed by activated carbon, preferably glue or gelatin is used. Needless to say, the additive concentration suitable for obtaining the target properties such as the hot elongation varies depending on the additive used. For example,
When gelatin is used as an additive, as shown in FIG. 3, by adjusting the additive concentration in the feed solution between 0 and 10 ppm, the hot elongation can be controlled within the range of 2% to 30%. A copper foil having a hot elongation rate corresponding to the additive concentration can be easily obtained.

The amount of liquid held in the process in the electrolytic copper foil manufacturing equipment is usually several hundred m ³ , though it depends on the scale. This electrolytic solution is circulated in the process and supplied to the electrolytic cell. At that time, the type and concentration of the additive in the electrolytic supply solution are important factors that determine the physical properties of the copper foil.

In the conventional method, old residual additives and their decomposition products and new additives are mixed in the electrolyte, and the residual additives and decomposition products are shown in FIG. Along with accumulating as shown,
Not only is it difficult to control the respective concentrations, but also the decomposition products of some additives may adversely affect the physical properties (tensile strength and elongation) of the copper foil depending on the additive.

On the other hand, in the method of the present invention, as shown in FIG. 5, the old additive and the decomposition product thereof in the electrolyte are removed by activated carbon treatment at every circulation cycle of the electrolyte. It is only necessary to control the concentration of, and there is an advantage that variations in foil properties due to old additives and the like can be reduced and the properties can be easily stabilized.

[0021]

EXAMPLES The present invention will be described below more specifically based on examples and comparative examples. Example 1 In a copper foil production facility shown in FIG. 2, a current density of 60 A / dm ² was obtained using an electrolytic solution adjusted to a copper ion concentration of 85 g / l, a sulfuric acid concentration of 150 g / l, and a chloride ion concentration of 30 mg / l. Continuous electrolysis was performed to prepare an electrolytic copper foil having a thickness of 35 μm. At this time, the replenishing solution is passed through the activated carbon tank 5 installed between the replenishing solution storage tank 4 'and the electrolytic cell 1 at an empty tower speed of 30 cm / sec, and thereafter, a food additive manufactured by Nitta Gelatin Co., Ltd. Water-soluble gelatin for products was continuously replenished with a metering pump so that the concentration in the replenishing solution was 5 ppm.

Example 2 In a copper foil production facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1, continuous electrolysis at a current density of 60 A / dm ² using an electrolytic solution adjusted to a chloride ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution is passed at a superficial velocity of 0 cm / sec, and thereafter, a water-soluble gelatin for food additives manufactured by Nitta Gelatin Co., Ltd. is continuously supplied with a metering pump so that the concentration in the replenishing solution becomes 2 ppm. Replenished.

Example 3 In a copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g /
1, continuous electrolysis at a current density of 60 A / dm ² using an electrolytic solution adjusted to a chloride ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution was passed at a superficial velocity of 0 cm / sec, and then a water-soluble gelatin for food additives manufactured by Nitta Gelatin Co., Ltd. was pumped by a metering pump so that the concentration in the replenishing solution was 0.2 ppm. Replenished continuously.

Example 4 In a copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l were used.
1, continuous electrolysis at a current density of 60 A / dm ² using an electrolytic solution adjusted to a chloride ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenisher is passed at a superficial velocity of 0 cm / sec, and then glycine used for a food additive manufactured by Showa Denko KK is continuously replenished by a metering pump so that the concentration in the replenisher becomes 15 ppm. did.

Example 5 In the copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution is passed at a superficial velocity of 0 cm / sec, and thereafter glycine used for a food additive manufactured by Showa Denko KK is continuously replenished with a metering pump so that the concentration in the replenishing solution becomes 10 ppm. did.

Example 6 In a copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenisher is passed at a superficial velocity of 0 cm / sec, and then glycine used for a food additive manufactured by Showa Denko KK is continuously replenished by a metering pump so that the concentration in the replenisher becomes 5 ppm. did.

Example 7 In a copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution was passed at a superficial velocity of 0 cm / sec, and then a polyvinyl alcohol (PVA) having a saponification degree of 98.5% used for cosmetics and the like manufactured by Kuraray Co., Ltd. was supplied at a concentration of 20 ppm in the replenishing solution. Was continuously replenished with a metering pump.

Example 8 In the copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution is passed at a superficial velocity of 0 cm / sec, and then a polyvinyl alcohol having a saponification degree of 98.5%, which is used for cosmetics and the like manufactured by Kuraray Co., Ltd., has a concentration of 10%.
It was continuously replenished with a metering pump so as to become ppm.

Example 9 In the copper foil manufacturing facility shown in FIG. 2, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g / l
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, 3 in activated carbon tank 5
The replenishing solution is passed at a superficial velocity of 0 cm / sec, and then a polyvinyl alcohol having a saponification degree of 98.5%, which is used for cosmetics and the like manufactured by Kuraray Co., Ltd., has a concentration of 5 p.
pm with a metering pump.

Comparative Example 1 In the copper foil manufacturing facility shown in FIG. 1, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g /
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, a water-soluble gelatin for food additives manufactured by Nitta Gelatin Co., Ltd., which was previously adjusted to a concentration of 5 ppm in the replenishing solution, was used. A copper foil was prepared using a metering pump p from the additive tank 6 of Example 1 while continuously adding at an additive concentration of 3.75 ppm, which is considered to be slightly higher than the consumption amount obtained from an empirical viewpoint.

Comparative Example 2 In the copper foil manufacturing facility shown in FIG. 1, a copper ion concentration of 85 g / l and a sulfuric acid concentration of 150 g /
1 and continuous electrolysis at a current density of 60 A / dm2 using an electrolytic solution adjusted to a chlorine ion concentration of 30 mg / l,
An m-thick electrolytic copper foil was prepared. At that time, a water-soluble gelatin for food additives manufactured by Nitta Gelatin Co., Ltd., which was previously adjusted to a concentration of 5 ppm in the replenishing solution, was used. A copper foil was prepared from the additive tank 6 by continuous addition at an addition concentration of 2.5 ppm, which is considered to be slightly less than the consumption equivalent obtained from an empirical viewpoint, using a metering pump p.

Table 1 shows the physical properties of the copper foils obtained from the electrolytes used in Examples 1 to 9 and Comparative Examples 1 and 2 for 10 days. When adding the additives in Examples 1 to 9, the amount of addition was calculated from the replenisher flow rate and the addition concentration. As is clear from Table 1, when the electrolysis is performed using the electrolytic solution which has been previously subjected to the activated carbon treatment as in the present invention, the additive has a hot elongation within the range of 2% to 30% depending on the amount of the additive. A copper foil having an elongation percentage according to the concentration can be stably manufactured over a long period of time.

[0034]

[Table 1]

The electrolyte solutions in Example 1 and Comparative Examples 1 and 2 were continuously used for 30 days, and the additive concentrations on the 10th, 20th and 30th days were analyzed, respectively. An evaluation was performed. Table 2 shows the results. As is clear from Table 2, according to the method of the present invention, it is possible to prevent degradation of the copper foil properties (for example, an increase in surface roughness, etc.) due to accumulation of decomposition products of the additive due to long-term continuous electrolysis and variation in concentration. .

[0036]

[Table 2]

As is clear from the above detailed description,
According to the present invention, the electrolytic solution supplied to the electrolytic cell is treated with activated carbon to completely remove the residual additive in the electrolytic solution once, and then the electrolytic replenishing solution is added to newly add a predetermined amount of the additive. It becomes possible to precisely control the concentration of the additive therein to a desired value. Therefore, the physical properties of the copper foil can be easily controlled. In addition, it is possible to selectively produce copper foils having different levels of hot elongation by adjusting the amount of the additive.

Further, according to the present invention, when added in a large amount, the physical properties of the copper foil may be adversely affected, and it is not necessary to use a highly toxic special additive. Since the substance can be used as an additive and no extra component is required in the electrolytic bath, an advantage that the concentration of the additive can be easily controlled can be achieved. Conventionally, making different copper foils with different physical property values in one production line is greatly affected by residual additives in the electrolyte, and it takes about 1 to 2 weeks for switching and startup,
Although practically manufactured on separate lines, the present invention is not affected by residual additives, so that copper foils having different physical properties can be easily manufactured on a single manufacturing line.

The above embodiment of the present invention is merely an example, and it goes without saying that various modifications are possible within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an outline of an electrolytic facility for implementing a conventional method.

FIG. 2 is a similar flowchart showing an outline of an electrolytic facility for carrying out the method of the present invention.

FIG. 3 is a graph showing the relationship between the concentration of gelatin as an additive and the hot elongation of electrolytic copper.

FIG. 4 is an explanatory view showing a state in which a residual additive and decomposition products accumulate in each circulation cycle of an electrolytic solution according to a conventional method.

FIG. 5 is an explanatory view showing a situation in which a residual additive and a decomposition product are removed in each circulation cycle of an electrolytic solution according to the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolysis tank 2 Tail liquid tank 3 Dissolution tower 4, 4 'Replenishment liquid storage tank 5 Activated carbon tower 6 Additive tank p Metering pump

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C25D 1/04

Claims (3)

(57) [Claims] 1. A copper foil for a printed wiring board is manufactured by electrodepositing copper on a rotating cathode drum in an electrolytic cell to which an electrolytic solution is supplied, and peeling the copper foil from the cathode drum while rotating the cathode drum. in a continuous electrolytic process for the supply of the dissolving tower
Replenisher tank for storing replenished replenisher and activated carbon treatment liquid.
An activated carbon tower is placed between the tank and the replenishing solution storage tank, and the electrolyte supplied into the electrolytic tank is emptied at a speed of 30 cm / sec or less.
In treated with activated carbon, the additive in the electrolyte replenishing solution after charcoal treatment
To control the elongation at 180 ° C.
A method for producing a copper foil for a printed wiring board, comprising obtaining a copper foil. 2. A method according to claim 1, wherein the additive is an organic material which is adsorbed by the activated carbon. 3. The method according to claim 2, wherein said additive is glue or gelatin.