KR102504286B1 - Surface treated copper foil and Method for producing the same - Google Patents

Abstract

A surface-treated copper foil according to an aspect of the present invention is a copper or copper alloy substrate; And a surface-treated copper foil comprising at least one or more of a rough plating treatment layer and a barrier layer formed on one or both surfaces of the substrate, wherein the surface-treated copper foil is a portion curved in an intaglio on the surface-treated surface It is characterized in that the number of micro grooves is 5 or less in the range of 50 μm × 50 μm in unit area.

Description

Surface treated copper foil and method for producing the same {Surface treated copper foil and Method for producing the same}

The present invention relates to a surface-treated copper foil, and more particularly, to a surface-treated copper foil with excellent peel strength and chemical resistance and a method for manufacturing the same.

Copper foil, which is a basic material used in the manufacture of printed circuit boards, is processed through a manufacturing process of manufacturing copper foil by electroplating and a post-treatment process of performing nodule treatment, chemical resistance treatment, heat resistance treatment, and rust prevention treatment on copper foil. are manufactured

The copper foil produced by the usual manufacturing process is peeled off from the cathode drum of the manufacturing equipment and is located on the other side of the shiny side (S side: Shiny Side) with relatively low roughness and relatively high roughness Includes a matte side (M side: Matte Side).

The copper foil is subjected to surface treatment to form copper nodules and barriers in a post-treatment process, thereby imparting physical and chemical properties suitable for printed circuit boards.

Through the post-treatment process, a copper nodule layer is formed on the mat surface (M surface) of the copper foil, and a barrier layer, which is a plating layer of nickel (Ni) or chromium (Cr), is formed on the copper nodule layer to provide heat resistance, hydrochloric acid resistance, and resistance to hydrochloric acid. Oxidation properties, etc. are imparted. A silane coupling agent is additionally coated on the barrier layer to improve adhesion with the resin film adhered to the copper foil.

The main physical and chemical properties of electrolytic copper foil are determined by the structure of the surface treatment layer. If the post-treatment process is not performed properly, the adhesion reliability between the copper foil and the resin film is not good, and the etching property, peel strength, bending resistance Deterioration may occur. In addition, there is also a problem that an etching solution or a developer penetrates between the copper foil and the resin during pattern formation in the PCB manufacturing process to decrease adhesive strength and cause product defects.

The present invention was devised to solve the problems of the prior art as described above, and by optimizing the micro groove, which is a curved part in the intaglio on the surface of the copper foil, a surface with excellent peel strength and chemical resistance. Its purpose is to provide a treated copper foil and its manufacturing method.

The surface-treated copper foil according to an aspect of the present invention for achieving the above technical problem is a copper or copper alloy substrate; And a surface-treated copper foil comprising at least one or more of a rough plating treatment layer and a barrier layer formed on one or both surfaces of the substrate, wherein the surface-treated copper foil is a portion curved in an intaglio on the surface-treated surface It is characterized in that the number of micro grooves is 5 or less in the range of 50 μm × 50 μm in unit area.

The surface-treated copper foil according to another aspect of the present invention for achieving the above technical problem is a copper or copper alloy substrate; and at least one or more of a rough plating treatment layer and a barrier layer formed on one or both surfaces of the substrate, wherein the surface-treated copper foil is formed on the substrate to be treated using an acid copper electrolysis bath. It is used as a cathode, and during the rough plating treatment, one side or both sides of the substrate is electrolyzed at a current density near the limit current density of the electrolysis bath to form a burning plating layer on the surface of the substrate, and after the surface treatment is completed, on the surface treated surface It is characterized in that there are 5 or less micro grooves in the range of a unit area of 50 μm × 50 μm, which is a curved part with an intaglio.

Preferably, in the surface-treated copper foil, the area ratio occupied by the micro grooves in a unit area of 50 μm × 50 μm on the surface-treated surface is 50% or less.

Preferably, the micro groove has a long diameter of 10 μm or more at a curved portion of the intaglio.

Preferably, the thickness of the surface-treated copper foil is 1 ~ 70㎛.

The above technical problem can be achieved by a copper-clad laminate to which the surface-treated copper foil according to the present invention is applied. In addition, it may be installed by a printed circuit board having a copper-clad laminate to which the surface-treated copper foil according to the present invention is applied.

A method for manufacturing a surface-treated copper foil according to an aspect of the present invention for achieving the above technical problem includes providing a copper or copper alloy substrate; And forming at least one or more of a rough plating treatment layer and a barrier layer formed on one surface or both surfaces of the substrate; It is characterized in that there are 5 or less micro grooves in the range of 50 μm × 50 μm in unit area, which is a curved part in the intaglio on the surface.

A method for manufacturing a surface-treated copper foil according to another aspect of the present invention for achieving the above technical problem includes providing a copper or copper alloy substrate; and forming at least one or more of a rough plating treatment layer and a barrier layer formed on one surface or both surfaces of the substrate, wherein the surface-treated copper foil is acid copper electrolyzed. Using a bath, the substrate to be treated is used as a cathode, and during the rough plating treatment, electrolysis is performed at a current density near the limit current density of the electrolysis bath on one side or both sides of the substrate to form a burning plating layer on the surface of the substrate, and surface treatment After completion, it is characterized in that there are no more than 5 micro grooves in the range of 50 μm × 50 μm in the unit area of the surface-treated surface.

According to the present invention, it is possible to implement a surface-treated copper foil having excellent peel strength and chemical resistance by optimizing a micro groove, which is a curved portion in an intaglio on the surface-treated surface of the copper foil.

The drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention serve to further understand the technical idea of the present invention, the present invention is limited only to those described in the drawings. and should not be interpreted.
1 is an explanatory diagram shown to explain the structure of a general electrodeposited copper foil manufacturing apparatus.
Figure 2 is an electron microscope (SEM) photograph of observing the micro groove (Micro Groove) of the surface-treated copper foil according to a preferred embodiment of the present invention.
FIG. 3 is a view showing the shape of a micro groove as the contour of the curved portion in the intaglio of FIG. 2 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to the usual or dictionary meaning, and the inventor appropriately uses the concept of the term in order to explain his/her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, since the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, various alternatives may be used at the time of this application. It should be understood that there may be equivalents and variations.

The surface-treated copper foil according to the present invention uses the following terms according to the process step. First, the copper foil manufactured through the conventional electrolytic filming apparatus shown in FIG. 1 is referred to as 'untreated copper foil', and the surface of the untreated copper foil subjected to electrochemical or chemical surface treatment is referred to as 'surface treated copper foil'. .

First, the untreated copper foil as a copper or copper alloy substrate is manufactured through the electrolytic forming apparatus of FIG. 1 . Referring to the drawings, a cylindrical drum 20 functioning as a cathode and a pair of arc-shaped anodes 30a and 30b are installed in an electrolytic cell C to which an electrolyte 10 is continuously supplied. The drum 20 rotates in the direction of the arrow, and the drum 20 and the pair of anodes 30a and 30b are spaced apart so that the electrolyte solution 10 can be interposed therebetween.

When manufacturing the electrodeposited copper foil, current is applied between the drum 20 and the pair of anodes 30a and 30b. At this time, the drum 20 is rotating in the direction of the arrow. Accordingly, after the electrodeposited copper foil 40 is electrodeposited on the surface of the drum 20, it is taken up through the guide roll 50.

The electrolyte 10 has copper sulfate as a main component, and various additives such as gelatin, HEC (Hydroxyethyl Cellulose), SPS (bis (sodiumsulfopropyl) disulfide) and nitride are added thereto, and the current density is preferably 10ASD to 80ASD. do.

The untreated copper foil, which is the copper or copper alloy base material, is completed as a 'surface treated copper foil' by performing the following surface treatment steps in order.

In order to obtain a surface-treated copper foil, a device called a surface treatment machine is generally used. 'Surface treatment' by passing the untreated copper foil wound in a roll shape from one direction and passing through a pickling treatment tank, a roughening treatment tank, an anti-rust treatment tank, an electrolytic chromate treatment tank, and a drying treatment unit, respectively, which are continuously arranged. Complete the 'Dongbak'.

The pickling treatment is a surface treatment process including a degreasing treatment for completely removing resin components adhering to untreated copper foil and a surface oxide film removal treatment. Through this pickling treatment, the untreated copper foil can be cleaned, and uniform electrodeposition can be secured in the remaining surface treatment steps. It is possible to use various solutions such as a hydrochloric acid-based solution, a sulfuric acid-based solution, and a sulfuric acid-hydrogen peroxide-based solution for this pickling treatment. It is sufficient to adjust the concentration, temperature, etc. of the solution according to the characteristics of the production line.

After the pickling treatment is finished, the untreated copper foil that has passed through the water washing tank enters a step of depositing and adhering fine copper particles. Here, since the copper electrolytic solution used must precipitate copper fine particles, a burning plating condition is employed. Therefore, the concentration of the solution used in the process of depositing and adhering the fine copper particles is lower than that of the solution used to form the untreated copper foil so as to easily create the burning plating conditions. These burning plating conditions are not particularly limited, and are determined in consideration of the characteristics of the production line. Thereafter, in order to prevent the deposited and adhered fine copper particles from falling off, a coating plating process is performed to uniformly deposit copper to cover the fine copper particles under smooth plating conditions. As a copper electrolyte solution for forming fine copper particles, 8 to 25 g/L of copper, 80 to 120 g/L of sulfuric acid, 50 to 300 mg/L of 9-phenylacridine, 30 to 40 ° C. liquid temperature, and 20 to 50 A/d current density ㎡ becomes the range that enables extremely stable electrolytic operation.

Next, a barrier layer is formed by performing alloy plating to prevent the surface of the electrolytic copper foil layer from being oxidized and corroded. That is, the plating for forming the barrier layer according to the present invention is copper (Cu), cobalt (Co), iron (Fe), nickel (Ni), zinc (Zn), chromium (Cr), vanadium (V), molybdenum It is made of two or more types of alloys selected from among (Mo).

After washing with water, an electrolytic chromate layer for rust prevention is formed on the surface of the copper foil on which the plating for forming the barrier layer is completed. The electrolysis conditions at this time are not particularly limited, but it is preferable to adopt the following conditions: 1 to 5 g/L of chromic acid, 20 to 40 °C liquid temperature, 10 to 12 pH, 0.5 to 4 A/dm2 current density, and 1 to 5 seconds of electrolysis time. desirable. These electrolysis conditions are range conditions for uniformly coating the surface of the electrodeposited copper foil.

After drying once the surface of the untreated copper foil on which the electrolytic chromate layer was formed in this way, adsorption treatment of a silane coupling agent is performed. The adsorption method of the silane coupling agent at this time is not particularly limited, such as an immersion method, a showering method, or a spray method. According to the design of the process, a method capable of contacting and adsorbing the copper foil and the solution containing the silane coupling agent most uniformly may be arbitrarily adopted. As the silane coupling agent, olefin-group-functional silanes, epoxy-group-functional silanes, acrylic-group-functional silanes, amino-group functional silanes (amino -group-introduced silanes) and mercapto-group functional silanes (mercapto-group functional silane) may be selectively used. Even if the silane coupling agents listed here are used for the adhesive surface of the copper foil substrate, it is important not to adversely affect the following etching process and the characteristics after becoming a printed wiring board.

On the other hand, in the manufacturing process of the present invention, in order to reduce the micro grooves on the surface of the copper foil that has been completed to the anti-rust treatment, it is necessary to manufacture a raw foil with a flat matte surface in the manufacturing process. To this end, it is important to maintain the rotation speed of the brush at 100 to 300 rpm and the left/right oscillating speed at 50 to 150 cycles/min when buffing the drum before stripping. In particular, the deviation of the buffing pressure should be less than 20% so that the drum surface is polished, and a flat original foil can be manufactured on a uniform drum surface. The R _max of the brush surface thus buffed should be kept below 2 μm.

In addition, in the surface treatment process of the present invention, the ratio of the total current applied for rough plating to the total applied current for powdering should be in the range of 0.5 to 2.0 times. In order to form a uniform nodule layer on the surface, the deviation of rough plating and powdering plating currents should be managed to less than 10%.

As such, the surface-treated copper foil of the present invention, which is produced through pickling treatment, roughening treatment, rust prevention treatment, chromate treatment, and silane coupling agent adsorption treatment on untreated copper foil, is characterized by having the following physical properties.

The surface-treated copper foil according to the present invention includes at least one layer of a rough plating treatment layer and a barrier layer formed on one surface or both surfaces of the substrate as described above in an untreated copper foil that is a copper or copper alloy substrate, the thickness is 1 to 70 μm, and micro grooves, which are intaglio curved portions on the surface-treated surface, are 5 or less in the range of 50 μm × 50 μm in unit area.

Figure 2 is an electron microscope (SEM) photograph of observing the micro groove (Micro Groove) of the surface-treated copper foil according to a preferred embodiment of the present invention, Figure 3 is a micro groove (Micro Groove) is a drawing showing the shape.

Referring to FIGS. 2 and 3, the intaglio curved portion (see the dashed-dot line in FIG. 2) visible when observed at approximately 1000 times with an electron microscope (SEM) on the surface-treated surface of the copper foil according to the present invention. Those having a diameter of 10 μm or more (see FIG. 3) are referred to as micro grooves.

In addition, the surface-treated copper foil according to the present invention uses an acid copper electrolysis bath to treat a substrate as a cathode, and during the rough plating process, one or both sides of the substrate is electrolyzed at a current density near the limiting current density of the electrolysis bath. to form a burning plating layer on the surface of the substrate, and after the surface treatment is completed, the thickness is 1 to 70 μm, and the micro groove, which is a curved part in the intaglio on the surface treated surface, has a unit area of 50 μm × 50 μm It is characterized in that it is 5 or less in the range of.

In addition, in the surface-treated copper foil according to the present invention, it is preferable that the area ratio occupied by the micro grooves is 50% or less in a unit area of 50 μm × 50 μm on the surface-treated surface.

As described above, the surface-treated copper foil according to the present invention has 5 or less micro grooves in the area of 50 μm × 50 μm on the surface-treated surface, and the area ratio occupied by the micro grooves is 50%. By forming to satisfy the following, it is possible to manufacture a surface-treated copper foil excellent in peel strength and chemical resistance.

This is when the number of micro grooves on the surface-treated surface of the copper foil exceeds 5 in a unit area of 50 μm × 50 μm, or when the area ratio occupied by the micro grooves exceeds 50%, This is because surface unevenness occurs, which hinders the bonding between the copper foil and the resin, thereby reducing peel strength, or excessive penetration of the etching solution into the edge portion of the pattern in the etching process for forming the circuit pattern, resulting in a decrease in chemical resistance.

Such peel strength and chemical resistance are important factors in the following aspects. In other words, if the peel strength is less than 1.0, after FPC is manufactured and mounted on an electronic device, if it is used under external shock and high temperature / high humidity conditions, the circuit pattern is separated and causes the failure of the electronic device, and liquid penetration of 30㎛ or more after chemical resistance evaluation When occurs, the lower part of the pattern is eroded by various chemicals in the FPC manufacturing process, causing a defect in which the pattern is detached from the resin.

The surface-treated copper foil having the characteristics described above can be made into a copper-clad laminate (single-sided copper-clad laminate or double-sided copper-clad laminate) by laminating an insulating layer such as a polyimide resin layer. The polyimide resin layer can be produced by polymerizing a known diamine and an acid anhydride in the presence of a solvent. It is also possible to manufacture a printed circuit board having this copper-clad laminate and having a predetermined circuit pattern formed on the copper-clad laminate by an etching process.

On the other hand, in the present invention, the rough plating treatment layer, the barrier layer, the rust prevention layer, and the silane treatment layer formed through the surface treatment of the untreated copper foil do not necessarily have to be performed in a specific order, and only some of these layers are formed. or it may be formed entirely.

Hereinafter, Examples and Comparative Examples will be described in detail to explain the present invention in detail. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Examples and Comparative Examples

Table 1 below shows the preferred implementation of the number (ea) of micro grooves and the area ratio (%) of micro grooves in the range of unit area 50 μm × 50 μm for the surface-treated copper foil according to the present invention. Peel strength and chemical resistance tests were conducted on Examples (1 to 5) and Comparative Examples (1 to 4), and the results are shown.

In Examples (1 to 5) and Comparative Examples (1 to 4) of the present invention, electrodeposited copper foil samples having the number and ratio of micro grooves in Table 1 after surface treatment were prepared. Here, the number and ratio of the micro grooves are observed in the range of 50 μm × 50 μm in unit area of the surface treated by 1000 times using an electron microscope (SEM), and the long diameter of the curved part in the intaglio is determined. The number of micro grooves of 10 μm or more was counted, and the area ratio was calculated by summing the areas of each micro groove.

Peel strength measurement of Examples and Comparative Examples

Samples in which the polyimide film was laminated on the surface-treated copper foil according to Examples (1 to 5) and Comparative Examples (1 to 4) were prepared, and for these samples, peeling between the copper foil and the polyimide film was performed according to the JIS C 6481 standard. Strength was measured. The results are shown in Table 1 above.

Chemical resistance evaluation of Examples and Comparative Examples

Samples in which a polyimide film was laminated on the surface-treated copper foil according to Examples (1 to 5) and Comparative Examples (1 to 4) were prepared, and a 1 mm circuit pattern was formed on the samples. Then, after immersing in sulfuric acid (5%) and fruit water (3%) soft etching solution (Etching Rate: 1.3㎛, etching rate controlled by liquid temperature) for 1 minute, the circuit pattern is peeled off to determine the penetration depth of the etching solution to the edge portion was measured. At this time, the liquid penetration depth was based on the deepest penetration depth, and after first checking the liquid penetration area at 500 times with an electron microscope (SEM), when confirming the penetration area, magnify it 1000 to 3000 times to measure the accurate liquid penetration depth did The results are shown in Table 1 above.

As can be seen from Table 1, the surface-treated copper foils according to Examples 1 to 5 of the present invention have a peel strength of 1.07 kgf/cm or more and a liquid penetration depth of 28 μm or less showing chemical resistance characteristics. It can be seen that both strength and chemical resistance exhibit excellent results.

On the other hand, in Comparative Example 1, although the number of micro grooves was 1, the area ratio was 53%, which did not meet the standard of the surface-treated copper foil according to the present invention, so the depth of liquid penetration was 37 μm, resulting in chemical resistance. I can confirm that this is not good.

In Comparative Example 2, although the number of micro grooves was 5, the area ratio was 51%, which did not meet the criteria for the surface-treated copper foil according to the present invention, so the peel strength was 0.98 kgf / cm and the liquid penetration depth. It can be seen that both peel strength and chemical resistance properties are not good at 58 μm.

In Comparative Example 3, although the area ratio of the micro grooves was 11%, the number of them was 6, which did not meet the standards of the surface-treated copper foil according to the present invention, so the liquid penetration depth was 35 μm, resulting in poor chemical resistance. can confirm.

In Comparative Example 4, although the area ratio of the micro grooves was 48%, the number of the micro grooves was 6, which did not meet the standards of the surface-treated copper foil according to the present invention, so the peel strength was 0.92 kgf / cm, and the liquid penetration depth was It can be seen that both peel strength and chemical resistance properties are not good at 78 μm.

Therefore, it can be confirmed that the surface-treated copper foil according to the embodiment of the present invention has excellent peel strength and chemical resistance characteristics compared to the surface-treated copper foil of Comparative Examples.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited thereto, and the technical spirit of the present invention and the following by those skilled in the art to which the present invention belongs Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

10: electrolyte 20: drum
30a, 30b: anode 40: untreated electrodeposited copper foil
50: guide roll

Claims (7)

copper or copper alloy substrates; And in the surface-treated copper foil comprising at least one or more layers of a rough plating treatment layer and a barrier layer formed on one surface or both surfaces of the substrate,
The surface-treated copper foil has 5 or less micro grooves in a unit area of 50 μm × 50 μm, which are intaglio curved portions on the surface-treated surface,
The surface-treated copper foil has an area ratio occupied by the micro grooves of 50% or less in a unit area of 50 μm × 50 μm on the surface-treated surface,
The micro groove (Micro Groove) is surface-treated copper foil, characterized in that the major diameter of the intaglio curved portion is 10㎛ or more. delete delete According to claim 1,
Surface-treated copper foil, characterized in that the thickness of the surface-treated copper foil is 1 ~ 70㎛. A copper-clad laminate characterized in that the surface-treated copper foil according to claim 1 is applied. A printed circuit board comprising the copper-clad laminate according to claim 5. Buffing the drum of the electrolytic filmmaking machine; providing a copper or copper alloy substrate through the electrolytic forming apparatus; And forming at least one layer of a rough plating treatment layer and a barrier layer formed on one surface or both surfaces of the substrate; In the method of manufacturing a surface-treated copper foil comprising,
The step of buffing the drum,
When buffing the drum, keep the rotational speed of the brush at 100 ~ 300rpm and the left/right oscillating speed at 50 ~ 150cycle/min.
The variation of the buffing pressure is less than 20%, and the Rmax of the buffed brush surface is maintained at 2 μm or less,
The surface-treated copper foil is a surface-treated copper foil manufacturing method, characterized in that the number of micro grooves (Micro Groove), which is a curved part in the intaglio on the surface-treated surface, is 5 or less in the range of 50 μm × 50 μm in unit area.

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