JP2002363786A - Apparatus for electrolytically manufacturing metal foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal foil manufacturing technology capable of eliminating etching irregularities caused when soft-etching a metal foil in a metal foil electrolytic manufacturing apparatus to peel off the metal foil by electro-depositing the metal on a circumferential surface of a drum-like cathode. SOLUTION: In the metal foil electrolytic manufacturing device 1 comprising the drum-like cathode 2 rotated in the predetermined direction, an anode 4 disposed facing the circumferential surface of the drum-like cathode 2, and an electrolyte feeding means to feed the electrolyte from a lower side of the drum-like cathode 2 in which the electrolyte 5 to be fed is allowed to overflow from an electrolyte outlet 7 formed of the drum-like cathode 2 and the anode 4, the metal is electro-deposited to the circumferential surface 3 of the drum-like cathode 2 by the electrolytic reaction, and the metal foil 8 is peeled off from the circumferential surface 3, a wave breaking body 13 for unifying the wave head of the electrolyte surface 9 in the width direction of the drum-like cathode 2 is disposed close to the circumferential surface 3 of the drum-like cathode 2 with respect to the surface 9 of the electrolyte overflowing from the electrolyte outlet 7 on the side where the circumferential surface 3 of the drum- shaped cathode 2 is advanced into the electrolyte 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for electrolytically producing a metal foil, and more particularly to an apparatus for electrolytically depositing a metal on a peripheral surface of a drum-shaped cathode by an electrolytic reaction to form a metal foil on the peripheral surface. The present invention relates to a technique for uniforming initial electrodeposition.

[0002]

2. Description of the Related Art In recent years, metal foils are used in various applications and are manufactured in large quantities, such as electrolytic copper foils, which are printed wiring board materials. As a method of manufacturing this metal foil,
A device utilizing an electrolytic reaction is known.

[0003] As a metal foil electrolytic manufacturing apparatus utilizing this electrolytic reaction, there is, for example, an apparatus for continuously manufacturing a metal foil using a drum-shaped cathode shown in FIG. This metal foil electrolytic manufacturing apparatus 1 includes a drum-shaped cathode 2 rotating in a certain direction,
An anode 4 arranged so as to face substantially half below the peripheral surface 3 of the drum-shaped cathode 2, and a liquid supply means for supplying an electrolyte 5 between the drum-shaped cathode 2 and the anode 4 from below the drum-shaped cathode 2. 6 is provided.

[0004] In this metal foil electrolytic production apparatus 1, an electrolytic solution 5 supplied from a liquid supply means 6 is supplied to a drum-shaped cathode 2 and an anode 4.
, That is, two liquid outlets 7 formed at approximately half positions above the peripheral surface 3 of the drum-shaped cathode 2, the electrolytic reaction proceeds to the peripheral surface 3 of the drum-shaped cathode 2 while overflowing. Metal is electrodeposited with the metal foil 8
Is continuously peeled off from the peripheral surface 3.

The metal foil obtained by the metal foil electrolytic manufacturing apparatus is used as follows, for example, in an electrolytic copper foil used as a material for a printed wiring board. The electrolytic copper foil obtained by using the copper sulfate electrolytic solution in the above-mentioned metal foil electrolytic manufacturing apparatus is subjected to a surface treatment such as rust prevention later, and is made into a surface-treated copper foil. Then, the surface-treated copper foil and the resin base material are laminated and bonded at a high temperature under pressure to form a copper-clad laminate for a printed wiring board.

[0006] This electrolytic copper foil is a basic material of a copper-clad laminate or a printed wiring board. To determine various characteristics of the copper-clad laminate or the printed wiring board, the foil thickness, surface roughness and elongation are determined. It is very important to control and manufacture copper foil characteristics such as strength and tensile strength.

[0007]

By the way, depending on the type of the printed wiring board, after forming a copper-clad laminate, the Ni-A
In order to apply u plating or the like, the copper foil surface of the copper-clad laminate may be subjected to soft etching. When a copper-clad laminate is formed using the electrolytic copper foil obtained from the above-described metal foil electrolytic manufacturing apparatus and the copper foil surface of the copper-clad laminate is subjected to soft etching, etching unevenness E as shown in FIG. It has recently been found to occur.

Although the etching unevenness is very thin in appearance, if Ni-Au plating with a small plating thickness is performed on the etching unevenness, the plating appearance will be deteriorated. Further, there has been a concern that such non-uniform Ni-Au plating treatment may adversely affect Au wire bonding in a later step.

The present invention has been made under the circumstances described above, and a metal is electrodeposited on the peripheral surface of a drum-shaped cathode by an electrolytic reaction, and the metal foil is peeled off from the peripheral surface. The present invention provides a metal foil manufacturing technique capable of eliminating etching unevenness that occurs when the metal foil is soft-etched in a metal foil electrolytic manufacturing apparatus for manufacturing a metal foil.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors examined the etching unevenness when the copper-clad laminate was subjected to a soft etching treatment. Not due to the copper foil surface treatment process,
The inventors found out that the cause was in the electrolytic copper foil itself obtained by the metal foil electrolytic manufacturing apparatus.

The etching unevenness E shown in FIG. 2 has a so-called wavy state, which is generated continuously and continuously, and is present over the entire width of the copper foil. Therefore, when the electrolytic copper foil itself was subjected to soft etching before the surface treatment was performed without using the copper-clad laminate, the same etching as that of the copper-clad laminate was performed on the glossy side of the electrolytic copper foil. It was confirmed that unevenness occurred.

The glossy surface of the electrolytic copper foil refers to the surface of the drum-shaped cathode which is electrodeposited on the peripheral surface, and corresponds to the surface corresponding to the back surface of the roughened surface which is the electrodeposition end surface. I say this. In the formation of the copper-clad laminate, the copper foil surface to be bonded to the resin substrate is the roughened side of the electrolytic copper foil, and the copper foil surface exposed when the copper-clad laminate is It is on the glossy side. Therefore, it has been clarified that etching unevenness that occurs when the copper foil surface is soft-etched when the copper-clad laminate is formed is caused by the glossy surface of the electrolytic copper foil.

The inventors of the present invention have studied in detail the electrodeposition behavior of the electrolytic copper foil produced by the above-mentioned electrolytic metal foil producing apparatus. Was found to be caused by the initial electrodeposition on the peripheral surface of.

Here, a metal foil electrolytic manufacturing apparatus 1 shown in FIG.
The electrodeposition behavior on the peripheral surface of the drum-shaped cathode will be described based on FIG. 3 in which a portion surrounded by an arrow A is enlarged. As shown in FIG. 3, on the peripheral surface 3 of the drum-shaped cathode 2 rotating in a certain direction, an arrow is drawn from a liquid outlet 7 formed by the drum-shaped cathode 2 and the anode 4 at a position approximately half above the peripheral surface 3. As shown by, the initial electrodeposition starts from the portion that comes into contact with the overflowing electrolytic solution 5.

In the direction of arrow B in FIG.
3, the overflowing electrolyte surface 9 was wavy in the width direction of the peripheral surface 3 of the drum-shaped cathode 2, as shown in FIG. 3. As a result of observing the wavefront shape of the electrolytic solution surface 9, the shape was almost the same as the etching unevenness E shown in FIG. From the above, the present inventors presumed the following about the initial electrodeposition on the peripheral surface of the drum-shaped cathode.

On the peripheral surface 3 of the drum-shaped cathode 2, a liquid outlet 7
The initial electrodeposition starts from the portion where it comes into contact with the electrolyte surface 9 overflowing from the surface. When viewed in the width direction of the peripheral surface 3, the initial electrodeposition is as shown in FIG. It will occur along the shape. In this case, the anode 4
Is fixed, so that the distance from the anode 4 is different between the peak and the valley in the wavefront shape of the electrolyte surface 5. As a result, the current density at the time of the initial electrodeposition is different between the peak and the valley in the wavefront shape of the electrolyte surface 9. That is, the initial electrodeposition as viewed in the width direction of the peripheral surface 3 is unevenly performed along the wavefront shape of the electrolyte surface 9 overflowing from the liquid outlet 7.

After such initial electrodeposition, the peripheral surface 3 is completely immersed in the electrolytic solution 5 by the rotation of the drum-shaped cathode 2, and the electrodeposition of the metal proceeds to form a metal foil having a predetermined thickness. Perimeter 3
It is peeled off from. That is, the electrolytic copper foil obtained from the metal foil electrolytic manufacturing apparatus shown in FIG. 1 has a glossy surface having the above-mentioned initial electrodeposition history. As a result of such initial electrodeposition, when the glossy surface of the electrolytic copper foil is soft-etched, uneven etching due to the initial electrodeposition state occurs.

As a result of the above intensive studies, the present inventors have developed the present invention of controlling the initial electrodeposition on the peripheral surface of the drum-shaped cathode in order to eliminate uneven etching on the glossy surface side in the soft etching process. I came to imagination.

According to the present invention, there is provided a drum-shaped cathode rotating in a certain direction, an anode arranged so as to face substantially half below the peripheral surface of the drum-shaped cathode, and a lower portion of the drum-shaped cathode disposed between the drum-shaped cathode. Liquid supply means for supplying an electrolytic solution from the side, and the electrolytic solution supplied from the liquid supply means overflows from a liquid outlet formed by the drum-shaped cathode and the anode while the drum-shaped cathode is formed by the electrolytic reaction. In the metal foil electrolytic manufacturing apparatus, in which a metal is electrodeposited on the peripheral surface of the metal foil, and the electrodeposited metal foil is continuously peeled off from the peripheral surface, the peripheral surface of the rotating drum-shaped cathode enters the electrolytic solution. With respect to the electrolyte surface overflowing from the liquid outlet, a wave absorber for equalizing the wave front of the electrolyte surface in the width direction of the drum cathode was disposed close to the peripheral surface of the drum cathode. .

According to the present invention, since the wave absorber is arranged at a position close to the peripheral surface of the drum-shaped cathode, the wave front of the electrolyte surface overflowing from the liquid outlet on the side where the initial electrodeposition is started. This equalizes the width of the peripheral surface, that is, cancels the wavefront shape of the electrolyte surface. Therefore, the wavefront shape of the electrolyte surface is equalized by the wavebreaker, and the initial electrodeposition occurs evenly in the circumferential width direction. The electrodeposited copper foil obtained by the metal foil electrolytic manufacturing apparatus in which the wave absorber was disposed did not cause etching unevenness on its glossy surface due to the soft etching treatment, as estimated by the present inventors.

In the wave absorber according to the present invention, the wave front shape of the electrolyte surface at which the initial electrodeposition is started needs to be linearly equalized in the circumferential width direction. Therefore, it is necessary to arrange the drum-shaped cathode as close as possible to the peripheral surface. If the distance from the peripheral surface is too large, the surface of the electrolytic solution that dissolves the initial electrodeposition becomes wavy, and the initial electrodeposition that causes uneven etching during soft etching is likely to occur. A similar effect can be expected by bringing the wave absorber into contact with the peripheral surface. However, in the metal foil electrolytic manufacturing apparatus of the present invention, the drum-shaped cathode is continuously rotated. In this case, it is assumed that the peripheral surface of the drum-shaped cathode may be damaged, or that foreign matter may adhere to the peripheral surface, making it impossible to stably produce the metal foil. However, if the wave absorber is made of a material that does not damage the peripheral surface of the rotating drum-shaped cathode and does not have any foreign matter attached thereto,
It is also possible to arrange in a state of contacting the peripheral surface.

It is preferable that the wave absorber according to the present invention is freely movable close to and away from the peripheral surface of the drum-shaped cathode. The metal foil electrolytic manufacturing apparatus according to the present invention, depending on the type of the metal foil to be manufactured, the device conditions and manufacturing conditions such as the distance between the anode and the drum-shaped cathode, the amount of supply of the electrolyte, and the manufacturing conditions are greatly different. The wavefront shape of the electrolyte surface overflowing from the mouth also varies. Therefore, according to the wave front shape of the electrolyte surface, the wave absorber is moved close to and away from the peripheral surface of the drum-shaped cathode so that the wave front shape of the electrolyte surface can be equalized over the peripheral surface width direction. Irrespective of conditions and the like, it is easy to equalize the initial electrodeposition.

[0023]

Preferred embodiments of the present invention will be described below.

The apparatus for manufacturing electrolytic metal foil in this embodiment has the structure shown in FIG. The metal foil electrolytic manufacturing apparatus 1 includes a drum-shaped cathode 2 rotating in a certain direction, and an anode 4 disposed to face the peripheral surface 3 of the drum-shaped cathode 2.
And The drum-shaped cathode 2 and the anode 4 are connected to a power supply device (not shown). The drum-shaped cathode 2 is disposed in the electrolytic cell 10 such that approximately half of the upper part of the peripheral surface 3 is immersed in the electrolytic solution 5. The anode 4 is divided into two parts, and an electrolytic solution supply means 6 for supplying an electrolytic solution 5 from below the drum-shaped cathode 2 is provided between the divided anodes 4. When the electrolytic solution 5 is supplied from the electrolytic solution supply means 6 toward the drum-shaped cathode 2, the electrolytic solution 5 flows so as to rise along the peripheral surface shape of the drum-shaped cathode 2 as shown by the broken line in FIG. And a drum-shaped cathode 2 and an anode 4
And overflows into the electrolytic cell 10 from the liquid outlet 7 formed therebetween. Peripheral surface 3 of drum cathode 2
The metal foil 8 formed by the electrolytic reaction is peeled off from the peripheral surface 3, and is taken up by a take-up roll 12 through a guide roll 11.
It is wound up.

FIG. 5 is an enlarged view of a portion surrounded by a dashed line A in FIG. 1 in the metal foil electrolytic manufacturing apparatus of the present embodiment. As shown in FIG. 5, in the metal foil electrolytic manufacturing apparatus according to the present embodiment, the drum-shaped cathode 2 is rotated near a liquid outlet 7 on the side where the peripheral surface 3 of the drum-shaped cathode 2 enters the electrolyte 5. A plate-like wave-eliminating block 13 having a length substantially equal to the width of No. 2 is arranged. This plate-like wave eliminating block 13
Are connected to a moving mechanism (not shown) at both ends in the width direction of the drum-shaped cathode, so that the plate-shaped wave eliminating block 13 can be approached and separated from the peripheral surface 3 of the drum-shaped cathode 2. Since the plate-like wave-eliminating block 13 is formed of an insulating material, it is possible to reduce the current flowing through the electrolyte surface 9 in contact with the peripheral surface at the time of initial electrodeposition. And the initial electrodeposition state in the circumferential width direction of the drum-shaped cathode can be further equalized.

Next, the result of manufacturing an electrolytic copper foil as a metal foil by the metal foil electrolytic manufacturing apparatus of the present embodiment described with reference to FIGS. 1 and 5 and soft etching the electrolytic copper foil will be described.

In the case of producing an electrolytic copper foil as a metal foil, a drum-shaped cathode whose peripheral surface is made of Ti (diameter 3 m, width 1.35)
m) and an insoluble anode called DSA, and a copper foil electrolytic production apparatus arranged so that a gap between the drum-shaped cathode and the insoluble anode was about 20 mm. The plate-like wave-eliminating block is made of vinyl chloride (height 55 mm, thickness 4).
(0 to 45 mm, length 1.35 m) was used. The plate-shaped wave-eliminating block facing the peripheral surface of the drum-shaped cathode was fixed so as to be 10 mm away from the peripheral surface.

As an electrolytic solution, a copper sulfate solution is used.
When the electrolytic solution was supplied from the electrolytic solution supply means at a flow rate of 0 to 900 L / min, the surface of the electrolytic solution overflowing from the liquid outlet, that is, the initial electrodeposition was started in a state where the plate-like wave eliminating block was not arranged. Electrolyte level is about 1-3 c
It had a wave shape with a height of about m. On the other hand, when the plate-like wave-eliminating block is arranged at the above-described position, the electrolytic solution surface is pressed by the plate-like wave-eliminating block, the wave shape of the electrolytic solution surface is completely eliminated, and initial electrodeposition starts. The electrolyte surface was linearly equalized in the circumferential surface width direction.

As described above, the plate-like wave eliminating block is arranged to
An electrolytic copper foil having a thickness of 8 μm is manufactured, and the electrolytic copper foil is immersed in a soft etching solution (concentrated sulfuric acid 100 mL / L + 35% hydrogen peroxide solution 20 mL / L, liquid temperature 30 ° C.) and subjected to a soft etching treatment for about 1 minute. Was done. After washing and drying, the surface of the electrolytic copper foil was observed. As a result, no etching unevenness was observed on the glossy surface side when the conventional plate-like wave-eliminating block was not disposed.

[0030]

According to the present invention, the initial electrodeposition of metal on the peripheral surface of the drum-shaped cathode when the metal is electrodeposited on the peripheral surface of the drum-shaped cathode by electrolytic reaction to form a metal foil is defined by the width of the peripheral surface in the circumferential direction. And can be made uniform. Therefore, it is possible to completely eliminate the uneven etching on the glossy surface that occurs when the electrolytic copper foil obtained from the electrolytic metal foil manufacturing apparatus is soft-etched.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a metal foil electrolytic manufacturing apparatus.

FIG. 2 is an external view of a glossy side of an electrolytic copper foil after soft etching.

FIG. 3 is a partially enlarged cross-sectional view of a metal foil electrolytic manufacturing apparatus.

FIG. 4 is an enlarged front view of the metal foil electrolytic manufacturing apparatus.

FIG. 5 is a partially enlarged cross-sectional view of the metal foil electrolytic manufacturing apparatus of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal foil electrolytic manufacturing apparatus 2 Drum-shaped cathode 3 Peripheral surface 4 Anode 5 Electrolyte solution 6 Liquid supply means 7 Liquid outlet 8 Metal foil 9 Electrolyte surface 10 Electrolyzer 11 Guide roll 12 Winding roll 13 Plate wave-eliminating block E Etching unevenness

Continued on the front page (72) Inventor Yoshikazu Tao 655-2 Kamakurabashi, Ageo City, Saitama Prefecture Copper Foil Division, Copper Foil Division, Mitsui Kinzoku Mining Co., Ltd.

Claims (2)

[Claims] 1. A drum-shaped cathode rotating in a certain direction, an anode arranged to face substantially half below the peripheral surface of the drum-shaped cathode, and a drum-shaped cathode disposed between the drum-shaped cathode and the lower side. A liquid supply means for supplying an electrolytic solution, wherein the electrolytic solution supplied from the liquid supply means overflows from a liquid outlet formed by the drum-shaped cathode and the anode, and the electrolytic solution reacts around the drum-shaped cathode. In a metal foil electrolytic manufacturing apparatus, in which a metal is electrodeposited on a surface and the electrodeposited metal foil is continuously peeled off from the peripheral surface, the liquid on the side where the peripheral surface of the rotating drum-shaped cathode enters the electrolytic solution. A wave absorber for equalizing the wave front of the electrolyte surface in the width direction of the drum-shaped cathode with respect to the electrolyte surface overflowing from the outlet is disposed close to the peripheral surface of the drum-shaped cathode. Metal foil electrolytic manufacturing equipment. 2. The metal foil electrolytic manufacturing apparatus according to claim 1, wherein the wave absorber is allowed to approach and separate from the peripheral surface of the drum-shaped cathode.