JPH04221091A - Production of electrolytic copper foil and apparatus therefor - Google Patents

Abstract

PURPOSE:To obtain a method and an apparatus for producing a new electrolytic copper foil capable of correcting thickness in the lengthwise direction during operation. CONSTITUTION:In order to reduce dispersion of thickness in the lengthwise direction of the green foil of an electrolytic copper foil, at least one part of an anode is constituted of a plurality of pieces of split anodes which are split in the width direction and used to uniform the thickness of the foil in the lengthwise direction. For example two sheets of circular arclike insoluble anodes 5 are provided by covering the immersed lower about half part of a cathode drum 1 and keeping the specified interval from the surface of the cathode drum. One part of the anode is constituted of the split anodes 9. The pattern of thickness in the lengthwise direction of the practically produced copper foil sample is measured. Slave rectifiers 7 regulate the amount of current between individual split anode and the cathode drum in accordance with this measured result.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing electrolytic copper foil.

0002

[Prior art] Electrolytic copper foil consists of an insoluble metal anode and a metal cathode with a mirror-polished surface.
By flowing an electrolytic solution between the drum and applying a potential between the anode and cathode drums, copper is electrodeposited on the surface of the cathode drum, and the electrodeposited material, which has reached a predetermined thickness, is peeled off from the cathode drum. Manufactured. The resulting copper foil is called raw foil.
It was later subjected to various surface treatments and made into products for printed circuits and other uses.

FIG. 5 is an explanatory diagram showing the arrangement relationship between a cathode body and an anode in conventional production of electrolytic copper foil. In an electrolytic cell (not shown) that stores an electrolytic solution, the cathode body 1 is installed so as to be able to rotate (here, clockwise) while being partially immersed in the electrolytic solution. For example, two anodes 5 are disposed to cover approximately the immersed lower half of the cathode barrel 1 and at a constant distance from the rotating barrel surface. 2 in the electrolytic cell
6 o'clock position between the two anodes 5 (position of the hour hand, same below)
An electrolyte is supplied from the cathode shell and the anode, and the electrolyte flows through the gap between the cathode body and the anode, overflows from the upper edge of the anode, and is circulated. A rectifier 6 maintains a predetermined voltage between the cathode shell and the anode.

As the cathode body 1 rotates, the thickness of the copper electrodeposited from the electrolyte increases, and at approximately the 12 o'clock position, the raw foil having a predetermined thickness is peeled off by an appropriate peeling means and wound up.

[0005] The raw foil produced in this way is used as an anode.
The thickness varies due to non-uniformity in the distance between the cathodes, the flow rate of the electrolyte supplied, the amount of electricity supplied, etc.

On the other hand, in electrolytic copper foil manufacturing equipment, after a certain period of operation, the spacing between the anode and cathode becomes uneven, especially due to wear and tear of the anode, and the equipment becomes unusable. In particular, the flow of the electrolyte differs between the ends and the center, resulting in variations in the thickness in the width direction.

The electrolytic copper foil produced in this way is shown in FIG.
As shown in the figure, there are variations in the thickness in the length direction and width direction.

In order to achieve a uniform thickness in the width direction of electrolytic copper foil, the following measures have conventionally been taken: (1
) Anode milling: In electrolytic copper foil manufacturing equipment, after the anode has been operated for a certain period of time, unevenness occurs between the anode and cathode due to wear and tear, and the anode becomes unusable. A state that cannot be used refers to a state in which the electrolytic voltage has increased abnormally or a state in which the thickness of the manufactured copper foil has large variations. To avoid this situation, the surface of anodes that have been used for a certain period of time is machined into a cylinder using a special cutting machine. (2) Partial scraping of the anode: After anode milling, the thickness variation in the width direction of the copper foil produced is measured, and according to the data, the surface of the anode is partially scraped off to correct the thickness of the copper foil.

In addition, at least a part of the anode is constituted as a plurality of divided anodes for making the thickness uniform in the width direction, and the amount of electricity to these divided anodes is individually controlled so that the thickness in the width direction of the electrolytic copper foil is uniform. This method is excellent in that the thickness in the width direction can be controlled during operation, and has achieved great results.

[0010] However, for some reason, there has been little awareness of the problem with the variation in the thickness of copper foil in the longitudinal direction.
It continues to this day.

[0011]

[Problems to be Solved by the Invention] Copper foil is mainly used for printed wiring boards, but as printed wiring boards become more dense, circuits become narrower and the thickness per layer decreases due to multilayering. At the same time as the copper foil becomes thinner, the demand for uniform thickness of the copper foil becomes more and more severe.

[0012] Along with this, it has become an important issue to solve the problem of uniformity of the thickness in the longitudinal direction, which has been overlooked in the past.

An object of the present invention is to develop a new method and apparatus for producing electrolytic copper foil that allows for longitudinal thickness correction during operation.

[0014]

[Means for Solving the Problems] The present inventors configured at least a part of the anode as a plurality of divided anodes for making the thickness uniform in the longitudinal direction, and the change in the longitudinal thickness of the produced electrolytic copper foil. We came up with the idea of controlling the amount of electricity to the divided anodes so that the thickness in the longitudinal direction is uniform according to the thickness.

Based on this knowledge, the present invention provides (1) flowing an electrolyte between a freely rotatable cathode shell and at least one anode facing the cathode shell, and depositing copper on the surface of the cathode shell. A method for manufacturing an electrolytic copper foil comprising depositing and peeling the electrodeposited copper foil from the cathode body, wherein at least a portion of the anode is configured as a segmented anode for making the thickness uniform in the longitudinal direction; A method for manufacturing an electrolytic copper foil, characterized in that the lengthwise thickness of the copper foil is made uniform by individually controlling the amount of electricity supplied to the divided anodes, and (2) a divided anode with uniform longitudinal thickness. The method for manufacturing an electrolytic copper foil according to (1) above, characterized in that the amount of electricity supplied to each cathode body is individually controlled based on the pattern of the longitudinal thickness of the copper foil per circumference of the cathode body, and (3) Electrolysis in which an electrolytic solution is flowed between a freely rotatable cathode shell and at least one anode facing the cathode shell, copper is electrodeposited on the surface of the cathode shell, and the electrodeposited copper foil is peeled off from the cathode shell. In the copper foil manufacturing apparatus, at least a part of the anode is configured as a segmented anode for making the thickness uniform in the longitudinal direction, and means for individually controlling the amount of electricity supplied to the segmented anode for making the thickness uniform in the longitudinal direction. (4) An electrolytic copper foil manufacturing apparatus characterized in that the thickness of the copper foil is made uniform in the longitudinal direction by providing an electrolytic copper foil manufacturing apparatus, and (4) the amount of electricity supplied to the divided anode for making the thickness uniform in the longitudinal direction is equal to There is provided an electrolytic copper foil manufacturing apparatus according to the above (3), characterized in that the apparatus is equipped with means for individually controlling the lengthwise thickness pattern of the copper foil.

[0016]

[Operation] According to the present invention, in order to reduce the variation in the longitudinal thickness of the raw electrolytic copper foil, at least a portion of the anode already explained in FIG. 5, preferably at least one sheet on the copper foil extraction side. Alternatively, a portion thereof may be configured as a plurality of divided anodes for making the foil thickness uniform in the length direction by being divided in the width direction. Of course, in addition to the existing anode, these divided anodes for making the foil thickness uniform in the longitudinal direction can be installed as auxiliary anodes.

[0017]

[Example] In FIGS. 1 and 2, a part of the anode on the copper foil drawer side of the two anodes is configured as a split anode (hereinafter simply referred to as split anode) 9 for making the foil thickness uniform in the longitudinal direction. Here is an example. Moreover, the divided anode may be a single sheet width divided anode without being divided in the width direction.

FIG. 3 shows an example in which a plurality of longitudinally divided anodes 9 are provided over the entire copper foil drawer side anode 5.
Each of these multiple rows may not be divided in the width direction, but may be made into a single width divided anode.

FIG. 4 shows an example in which not only the anode on the copper foil draw-out side but also a part of the anode on the electrodeposition start side is constructed as a longitudinally divided anode.

[0020] The number of divisions in the width direction and the number of rows of divided anodes can be controlled more precisely as they increase, but production and maintenance are accordingly more difficult, and the number of divisions in the width direction and the number of rows of divided anodes can be controlled accordingly. Each row is divided into 10 to 40 pieces, usually around 20 to 30 pieces.

[0021] The operational mode of electrolytic copper foil production will be explained using the examples shown in FIGS. 1 and 2.

In an electrolytic cell (not shown) containing an electrolytic solution, such as a sulfuric acid solution of copper sulfate, a rotating cylindrical cathode body 1, made of stainless steel or titanium, for example, is partially immersed in the electrolytic solution; Here it is mounted by means of a support device so that it can be rotated clockwise.

[0023] Covering approximately the immersed lower half of the cathode shell 1 and spaced apart from the surface of the cathode shell by, for example, two
A circular arc-shaped insoluble anode 5 is provided. The insoluble anode is made of lead, a lead alloy of lead and antimony, silver, indium, or the like. Alternatively, the insoluble anode is DSE
Or DSA (Dimension StableE
It may have a structure in which a valve metal represented by titanium is coated mainly with a platinum group metal or an oxide thereof. The anode preferably consists of two anode sheets disposed along approximately the lower quarter of the cathode barrel as shown, but in some cases more such as one, three or four sheets may be used. It can also be constructed from many anode sheets.

According to this specific example, a portion of one sheet of the anode on the copper foil extraction side is configured as the split anode 9 as described above. Appropriate number of divided anodes 9', 9''
,... are formed. As described above, the longitudinally divided anode 9 may be a single width divided anode without being divided in the width direction.

[0025] The distance between the cathode body and the anode is usually 2 to 100 m.
It is maintained at a constant position within a range of m. The narrower the spacing, the less electricity is required, but it becomes more difficult to control film thickness and quality.

The gap between the cathode body and the anode forms a flow path for the electrolyte. Electrolyte is supplied from the 6 o'clock position between the two anodes 5 through a suitable pump (not shown) in the tank, and the electrolyte flows to both sides through the gap between the cathode body and the anode to the upper edge of each anode. It overflows and is circulated.

A rectifier 6 maintains a predetermined voltage between the cathode shell and the anode.

As the cathode body 1 rotates, the electrodeposition of copper from the electrolyte starts at approximately the 3 o'clock position, gradually increases in thickness, and ends at approximately the 9 o'clock position to reach a predetermined thickness. The raw foil, which has reached a predetermined thickness at approximately the 12 o'clock position, is peeled off by an appropriate peeling means and wound up.

However, as described above, local variations in the thickness in the longitudinal direction occur in the green foil due to non-uniformity in the flow rate of the electrolytic solution supplied or the amount of electricity supplied.

According to this embodiment, the thickness pattern per circumference of the cathode body is measured at several positions in the length and width directions of an actually manufactured copper foil sample, and the child rectifier 7 is adjusted according to the measurement results. adjusts the amount of current between the individual segmented anodes and the cathode body.

In the present invention, the thickness pattern per circumference of the cathode shell means that when the copper foil produced when the cathode shell goes around is divided into, for example, 36 parts in the length direction and 20 parts in the width direction, The thickness of the copper foil was measured at 36×20=720 locations, and the state of variation in the thickness at the 720 locations was shown.

Although the variation in the thickness of the copper foil decreases as the number of divisions in the length and width directions increases, if maintenance of the control device for this purpose is taken into consideration, normally 1.
0-40 is preferred.

Measurement of the thickness at each position in the width direction of the copper foil is as follows:
This can be easily done by measuring the weight per unit area by appropriate sampling, or a thickness measuring device such as a capacitance sensing type can also be used.

An insulating seal is preferably provided between each segmented anode. As the insulating seal material, a PVC board, room temperature vulcanized rubber (RTV: trade name), etc. can be used. In addition to this, it can also be achieved, for example, by joining adjacent divided anodes with an insulating adhesive or by integrating the divided anodes with an insulating film in between.

According to the invention, individual control of the segmented anodes can also be carried out by controlling their respective set positions. Apart from the support device for supporting the anodes in the electrolyte, means are provided for individually supporting the segmented anodes and for moving the individual segmented anodes towards or away from the cathode barrel. These divided anodes are moved back and forth by an appropriate position adjustment mechanism such as a screw mechanism or a piston-cylinder mechanism. A support rod of a specific divided anode corresponding to a specific region is displaced by a position adjustment mechanism. The closer the segmented anode is to the cathode shell, the higher the current density and the greater the thickness of the electrodeposited copper. Conversely, as the divided anode is separated from the cathode body, the current density decreases and the thickness of the electrodeposited copper decreases.

Thus, according to the present invention, manufacturing can be carried out by individually controlling the amount of electricity supplied to the divided anodes for making the foil thickness uniform in the longitudinal direction, or by individually controlling the setting positions thereof. The longitudinal thickness of the electrolytic copper foil can be made uniform.

(Example 1) Diameter 2.0m and width 1.3m
A copper foil with a thickness of 35 μm was manufactured using a copper sulfate solution using a cathode body and two anodes with a width of 1.3 m arranged along the lower half of the cathode body as shown in the figure. I did it. As the anode configuration according to the present invention, the configuration shown in FIGS. 1 and 2 was used, and the longitudinally segmented anode was composed of 20 segmented anodes.

Then, based on the pre-measured pattern of the longitudinal thickness per circumference of the cathode shell (width direction: 20 x length direction: 36 = 720), each anode was sized to a thickness of 0.1 by using a computer. It was adjusted in the range of ~10 A/dm2. As a result, the variation in the thickness in the longitudinal direction was reduced by the method of the present invention, and was able to be reduced from the conventional variation of about 3% to 0.5% or less.

(Example 2) As an anode structure according to the present invention, two
A copper foil having a thickness of 35 μm was manufactured in the same manner as in Example 1, by arranging longitudinally divided anodes consisting of 0 divided anodes. The thickness variation in the length direction of the obtained copper foil is 0.
．． It was less than 5%.

[0040]

[Effect of the invention] This has not been considered much in the past.
We succeeded in reducing the variation in thickness in the length direction due to non-uniformity in the flow rate of the electrolyte supplied or the amount of electricity supplied. By using this method in combination with a means to control the variation in thickness in the width direction, high quality copper foil with uniform thickness can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the arrangement relationship between the cathode body and the anode in an embodiment in which a part of the anode on the copper foil drawer side of the two anodes is configured as a divided anode for equalizing the foil thickness; .

FIG. 2 is a perspective view of the anode of FIG. 1;

3 is a perspective view of a specific example of an anode in which the entire copper foil drawer-side anode of FIG. 2 is constructed as a plurality of longitudinally divided anodes; FIG.

FIG. 4 shows an example in which a part of the electrodeposited anode is also configured as a longitudinally divided anode.

FIG. 5 is an explanatory diagram showing the arrangement relationship between a cathode body and an anode in conventional electrolytic copper foil production.

[Explanation of sign]

1 Cathode body 2 Central axis 4. Outer peripheral wall 5 Anode 6 Rectifier 7 Child rectifier 9 Split anode

Claims (4)

[Claims] Claim 1: An electrolytic solution is flowed between a rotatable cathode shell and at least one anode facing the cathode shell, copper is electrodeposited on the surface of the cathode shell, and the electrodeposited copper foil is attached to the cathode. In a method for producing an electrolytic copper foil that is peeled off from a shell, at least a portion of the anode is configured as a segmented anode for making the thickness uniform in the longitudinal direction, and the amount of electricity supplied to the segmented anode for making the thickness uniform in the longitudinal direction is individually controlled. 1. A method for producing electrolytic copper foil, characterized by making the thickness of the copper foil uniform in the longitudinal direction by controlling the thickness. 2. Claim 1, wherein the amount of electricity supplied to the divided anodes for making the thickness uniform in the longitudinal direction is individually controlled based on the pattern of the longitudinal thickness of the copper foil per circumference of the cathode body. A method for producing electrolytic copper foil. 3. An electrolytic solution is flowed between a rotatable cathode shell and at least one anode facing the cathode shell, copper is electrodeposited on the surface of the cathode shell, and the electrodeposited copper foil is attached to the cathode. In an apparatus for manufacturing electrolytic copper foil that is peeled off from a shell, at least a portion of the anode is configured as a segmented anode for making the thickness uniform in the longitudinal direction, and the amount of electricity supplied to the segmented anode for making the thickness uniform in the longitudinal direction is individually controlled. 1. An electrolytic copper foil manufacturing apparatus characterized by comprising means for controlling the thickness of the copper foil in the longitudinal direction. 4. The method further comprises means for individually controlling the amount of electricity supplied to the divided anodes for making the thickness uniform in the longitudinal direction based on the pattern of the longitudinal thickness of the copper foil per circumference of the cathode body. 4. The electrolytic copper foil manufacturing apparatus according to claim 3.