TWI728012B - High-chroma processed copper foil, copper clad laminate using the processed copper foil, and manufacturing method of the processed copper foil - Google Patents

Abstract

The present invention provides a processed copper foil that has low transmission loss and can maintain high peel strength regardless of whether it is under normal conditions or after heating or after chemical immersion. In addition, the HAZE value of the etched part is low, and it can be applied to the etched part and wiring. The clear boundary of the pattern part corresponds to the high-speed/high-frequency transmission printed circuit board. A treated copper foil for a copper clad laminate, which is provided with an anti-oxidation treatment layer on at least one surface of the untreated copper foil surface, and the ten-point average roughness RzJIS94 of the treated surface is 1.2 μm or less (not including 0 μm). The treated layer contains cobalt and molybdenum. In the color system XYZ (Yxy) defined in JIS Z 8701 on the treated surface subjected to the anti-oxidation treatment, Y is 10 to 30, x is 0.24 to 0.31, and y is 0.29 to 0.33.

Description

High-chroma processed copper foil, copper clad laminate using the processed copper foil, and manufacturing method of the processed copper foil

FIELD OF THE INVENTION The present invention relates to a processed copper foil capable of producing a copper-clad laminate. The processed copper foil can be applied to a printed circuit board corresponding to high-speed/high-frequency transmission. The color of the processed surface of the processed copper foil is high chroma. In a printed circuit board prepared by etching a copper-clad laminate of processed copper foil, the adhesiveness and high-frequency transmission characteristics of the processed copper foil and the resin substrate are excellent, and the HAZE value of the resin substrate exposed by etching is low. The boundary line between the etching part and the wiring pattern part can be accurately seen by the CCD camera, and therefore, the alignment during installation and the inspection of the optical appearance automatic inspection device can be accurately performed.

BACKGROUND OF THE INVENTION A printed circuit board used in information communication equipment and the like is formed by forming a conductive wiring pattern on a resin substrate, and it can be manufactured by the following method: the resin substrate and copper foil are heated and pressurized to produce a coating The copper laminate is then formed by removing unnecessary parts of the copper foil by etching in order to form a wiring pattern.

Examples of resin substrates used for printed circuit boards include: insulating phenol resin, epoxy resin, polyphenylene ether resin, bismaleimide triazine resin, etc. impregnated with reinforcing materials such as glass cloth or paper Resin substrates for rigid printed circuit boards; and resin substrates for flexible printed circuit boards composed of polyimide resins or cycloolefin polymer resins.

As the material of the conductive wiring pattern, copper foil is generally used.

Copper foil is divided into two categories: electrolytic copper foil and rolled copper foil according to its manufacturing method, and they are used according to their respective characteristics. No matter what kind of copper foil, it will hardly be used directly. Instead, it uses a copper foil that includes a roughening treatment layer and is provided with various treatment layers such as a heat-resistant treatment layer and a rust-proof treatment layer (hereinafter, various treatment layers will be provided) The copper foil is called "processed copper foil").

As one of the important characteristics of using a printed circuit board without any problems in practical use, the adhesion between the resin base material and the copper foil, that is, the peel strength, can be cited.

Needless to say, the peel strength needs to be in a normal state, and it does not deteriorate even after heating or after chemical immersion, and maintains high peel strength.

As one of the effective means to improve the peel strength in normal conditions, after heating, and after chemical impregnation, it is usually done to provide a roughening treatment layer on the copper foil.

Recently, the demand for printed circuit boards corresponding to high-speed/high-frequency transmission has been increasing. In addition to adhesion, transmission characteristics represented by transmission loss have become one of the important characteristics of printed circuit boards that support high-speed/high-frequency transmission.

Transmission loss refers to the degree to which the current flowing through the printed circuit board attenuates in accordance with the distance, etc. Generally, the transmission loss tends to increase as the frequency increases. If the transmission loss is large, only a part of the predetermined current is transmitted to the load side. Therefore, in order to be used without any problems in practical use, it is necessary to suppress the transmission loss even lower.

The transmission loss of a printed circuit board is a loss that combines dielectric loss and conductor loss. The dielectric loss comes from the resin base material and is caused by the dielectric constant and the dielectric loss tangent.

On the other hand, conductor loss originates from the conductor, that is, copper foil, and is caused by conductor resistance.

Therefore, in order to reduce the transmission loss, it is necessary to reduce the dielectric constant and the dielectric loss tangent of the resin base material and to reduce the conductor resistance of the copper foil.

The tendency of the transmission loss to increase as the frequency of the current increases is because the conductor loss, that is, the conductor resistance increases, is related to the "skin effect" and "treatment of the surface shape of the copper foil".

The skin effect refers to the effect that the current flowing through the conductor flows closer to the surface of the conductor as the frequency becomes higher. Furthermore, the skin depth δ defined as the distance to the point where the current on the surface of the conductor becomes 1/e times the current is expressed by equation (1). δ=(2/(ωσμ)) ^1/2 (1) where ω is the angular frequency, σ is the electrical conductivity, and μ is the magnetic permeability. In the case of copper, according to its electrical conductivity and relative permeability, the formula (1) is as follows. δ=0.066/f ^1/2 (2) where f is the frequency. It can be seen from equation (2) that the current flows closer to the surface of the conductor as the frequency becomes higher. For example, when the frequency is 10MHz, the skin depth is about 20μm. In contrast, when the frequency is 40GHz, it becomes About 1μm, almost only flows on the surface.

In order to improve the peeling strength from the resin substrate as in the prior art, when a high-frequency current is applied to the processed copper foil provided with a roughened layer, the current will flow along the surface shape of the roughened layer, and Compared with the case where the main pen passes through the center, the propagation distance increases, so the conductor resistance increases, resulting in increased transmission loss.

If you focus on the transmission loss, it is considered that the smaller the particle diameter of the roughened particles constituting the roughened layer, the shorter the propagation distance, and the transmission loss can be suppressed. Therefore, it is ideally not suitable for printing that supports high-speed/high-frequency transmission. The processing copper foil of the circuit board is roughened.

However, if attention is paid to adhesiveness, since the anchoring effect of the processed copper foil which does not have a roughening process layer is small, the adhesiveness with a resin base material is weak, and it is difficult to ensure a peeling strength.

In this way, it can be said that the improvement of the adhesion and the suppression of the transmission loss are contradictory characteristics.

In addition, it is not limited to printed circuit boards that support high-speed/high-frequency transmission. The resin base material after the wiring pattern of the printed circuit board is formed has high transparency and can clearly identify the etching part and the wiring pattern part (copper foil residual part). The visibility of boundaries can also be cited as one of the important characteristics.

This is a characteristic obtained by using an anisotropic conductive film (hereinafter, sometimes referred to as "ACF") as a mounting technique that does not use soldering.

When connecting a printed circuit board (hereinafter, sometimes referred to as "PCB") and a flexible printed circuit board (hereinafter, sometimes referred to as "FPC") up and down, the ACF is inserted between them and heated and pressurized. Continuity in the up and down direction. If the FPC and PCB are not reliably aligned, the upper and lower continuity cannot be obtained. Therefore, the positioning marks are marked on them, and these marks are aligned with the CCD camera.

Since the alignment is performed by the CCD camera from directly above the resin substrate exposed through the copper foil of the etched FPC, if the resin substrate is blurred, the transparency will be low, and it will be difficult to identify the mark and the alignment will not be correct.

Therefore, in order to carry out correct alignment, the haze of the exposed resin substrate is preferably as low as possible, and the transparency is preferably high.

In addition, in recent years, the completion inspection of printed circuit boards by an optical automatic appearance inspection device (hereinafter, sometimes referred to as "AOI") is also one of the reasons for achieving visibility. AOI is a device that optically grasps the wiring pattern of a printed circuit board and judges whether it is good or not through image processing. It can detect defects such as pattern defects, over-thickness, over-thinness, pinholes, and damage.

If the copper foil of the printed circuit board is etched and the exposed resin substrate is blurred, the transparency is low. Therefore, the wiring pattern cannot be grasped and accurate inspection cannot be performed.

Therefore, in order to perform a correct inspection, it is best that the haze of the exposed resin substrate is as low as possible and the transparency is high.

The haze of the resin substrate can be quantified by measuring the HAZE value. Generally, if the HAZE value is below 80%, the transparency is high and it is easy to see.

The HAZE value is strongly affected by the surface shape of the treated copper foil. If the diameter of the roughening particles constituting the roughening treatment layer or the surface roughness of the treated copper foil is small, or the roughening treatment is not applied, the HAZE value is low , High transparency.

However, if the particle diameter of the roughened particles is small, or the roughening treatment is not performed, the anchoring effect is small and the adhesion to the resin substrate is weak, so it is difficult to ensure the peel strength.

In this way, it can be said that closeness and transparency are contradictory characteristics.

As described above, the adhesion between the resin base material and the copper foil, transmission characteristics, and transparency are contradictory characteristics, and a printed circuit board compatible with high-speed/high-frequency transmission must satisfy the above-mentioned characteristics practically.

In addition, in order to perform accurate alignment and inspection, the boundary between the resin base material and the wiring pattern (copper foil residue) exposed by etching should be clear.

Therefore, it is expected to develop a treated copper foil for printed circuit boards that has sufficient peel strength from the resin substrate, and the transmission loss is as excellent as that of untreated copper foil, and the HAZE value of the resin substrate exposed by etching the copper foil It is relatively low and has high transparency, and the boundary between the exposed resin base material and the wiring pattern is clear, and the visibility is excellent. Prior Art Documents Patent Documents

Patent Document 1: Japanese Patent Application Publication No. 2013-155415 Patent Document 2: Japanese Patent Application Publication No. 2014-111814

SUMMARY OF THE INVENTION Problems to be Solved by the Invention Patent Document 1 discloses a treated copper foil provided with a roughening treatment layer and a heat-resistant treatment layer in order to improve the adhesion to an insulating resin corresponding to high-frequency transmission.

Since the insulating resin corresponding to high-frequency transmission has fewer highly polar functional groups that contribute to adhesion and lower adhesion properties, the treated copper foil disclosed in Patent Document 1 increases the particles that constitute the roughened layer. To ensure peel strength. However, if the coarsening particles are larger, the current propagation distance becomes longer, and the problem of increased transmission loss occurs.

In addition, there is the following problem: the heat-resistant treatment layer, the rust-preventing treatment layer, and the silane coupling agent layer will further increase the transmission loss. Especially when the heat-resistant treatment layer contains nickel, the skin depth becomes shallow, so the current will be reduced. Concentrated on the surface of the copper foil, the flow is further affected by the unevenness of the processing layer, and the transmission loss will further increase.

In Patent Document 2, a method is proposed: as a surface-treated copper foil that adheres well to resin and achieves excellent visibility when viewed through the resin, a copper-cobalt-nickel copper foil is applied to a low-thickness copper foil. After the roughening treatment of the structure, a cobalt-nickel layer is applied as a rust preventive treatment, and a zinc or zinc-nickel layer is further applied.

However, it has been found that this method has the following problems: the transparency after etching is low, and the use of nickel in the rust-preventive layer results in high transmission loss and low chemical resistance, which may cause problems when immersed in an active treatment solution. Penetration occurred.

The inventors of the present invention took the solution of each of the above-mentioned problems as a technical problem, and repeated trial and error trial production and experiments. As a result, they obtained the following findings that should be paid attention to, and completed the above-mentioned technical problems. An anti-oxidation treatment layer is provided on at least one surface of an untreated copper foil, the ten-point average roughness RzJIS94 of the treated surface is less than 1.2 μm, the anti-oxidation treatment layer contains cobalt and molybdenum, and the anti-oxidation treatment is performed In the color system XYZ (Yxy) defined by JIS Z 8701 on the treated surface, Y is 10-30, x is 0.24-0.31, and y is 0.29-0.33. If it is such a processed copper foil, even if no roughening treatment is provided The layer can also ensure the peel strength with the resin substrate, and because there is no roughening treatment layer, it has excellent transmission characteristics. In addition, because the treated copper foil and the resin substrate are bonded together in the copper clad laminate The resin substrate exposed by etching has a low HAZE value and a clear boundary between the etched part and the remaining part of the processed copper foil (wiring pattern part). The visibility is excellent. Therefore, it is possible to accurately perform AOI inspections using CCD cameras and use ACF Optical positioning during connection. Means to solve the problem

The technical problem can be solved by the present invention.

The treated copper foil for a copper clad laminate of the present invention is provided with an anti-oxidation treatment layer on at least one surface of the untreated copper foil, and the ten-point average roughness RzJIS94 of the treated surface is 1.2 μm or less (not including 0 μm), wherein, The anti-oxidation treatment layer contains cobalt and molybdenum, and in the color system XYZ (Yxy) defined in JIS Z 8701 on the treated surface subjected to the anti-oxidation treatment, Y is 10-30, x is 0.24-0.31, and y is 0.29 to 0.33 (the first aspect of the present invention).

In addition, the treated copper foil for a copper-clad laminate according to the first aspect of the present invention, wherein the content of molybdenum contained in the anti-oxidation treatment layer is 25 to 50% by weight (the second aspect of the present invention ).

In addition, the treated copper foil for a copper clad laminate according to the first or second aspect of the present invention, wherein a chromate layer and/or a silane coupling agent layer (this The third aspect of the invention).

In addition, the treated copper foil for a copper-clad laminate according to any one of the first to third aspects of the present invention, wherein the treated copper foil is bonded to both sides of an insulating resin substrate A copper-clad laminate in which the entire surface of either side of the copper-clad laminate is etched and the other side is partially etched, or only one side of the insulating resin substrate is laminated with the processed copper foil and the processed copper foil In the partially etched copper clad laminate, the HAZE value of the T part below is 60% or less, and the L* of the color system L*·a*·b* defined by JIS Z 8781 from the following D direction is 88 ～100, a* is -0.14～1.10, b* is the range of -0.13-15, the color of the T part of the color system L*・a*・b* and the remaining part of the treated copper foil measured on a single color The difference E*ab is 60 or more (the fourth aspect of the present invention), T part: the copper clad laminate with the treated copper foil on both sides is the part where both sides are etched, and the copper clad with the treated copper foil on only one side Laminate is the etched part; D direction: the copper clad laminate with the treated copper foil on both sides is the direction of the surface where the entire surface is etched, and the copper clad laminate with the treated copper foil on only one side is equipped Process the opposite direction of the copper foil surface.

In addition, a copper-clad laminate of the present invention, wherein the treated copper foil for a copper-clad laminate according to any one of the first to fourth aspects of the present invention is bonded to at least one surface of an insulating resin substrate (The fifth aspect of the present invention).

In addition, according to the copper-clad laminate according to the fifth aspect of the present invention, the entire surface of either side of the copper-clad laminate on which the treated copper foil is attached to both sides of the insulating resin substrate is etched and A copper-clad laminate in which etching is partially performed on the other side, or a copper-clad laminate in which the processed copper foil is attached to only one side of an insulating resin substrate and the processed copper foil is partially etched, wherein the following T The HAZE value of the part is 60% or less, and the color system L*・a*・b* defined by JIS Z 8781 from the following D direction is 88-100, a* is -0.14-1.10, and b* is The color difference E*ab between the T portion of the color system L*·a*·b* and the remaining portion of the treated copper foil measured on a single color in the range of -0.13-15 is 60 or more (the sixth aspect of the present invention) ), T part: the copper clad laminate with the treated copper foil on both sides is the part where both sides are etched, and the copper clad laminate with the treated copper foil on only one side is the etched part; D direction: both sides are provided The copper-clad laminate of the treated copper foil is in the direction of the surface where the entire surface is etched, and the copper-clad laminate provided with the treated copper foil on only one side is in the opposite direction to the surface of the treated copper foil.

In addition, the copper-clad laminate according to the fifth or sixth aspect of the present invention, wherein the insulating resin substrate is a resin substrate containing a polyimide compound (a seventh aspect of the present invention).

In addition, a method for producing a treated copper foil for a copper-clad laminate according to any one of the first to fourth aspects of the present invention, wherein the anti-oxidation treatment is formed by an alkaline electrolytic bath containing cobalt and molybdenum Layer (the eighth aspect of the present invention).

In addition, the method for producing a treated copper foil for a copper-clad laminate according to the eighth aspect of the present invention, wherein the alkaline electrolytic bath is an electrolytic bath containing pyrophosphoric acid (the ninth aspect of the present invention).

In addition, the method for manufacturing a copper-clad laminate according to any one of the fifth to seventh aspects of the present invention is characterized in that the treated copper foil for the copper-clad laminate and the insulating resin substrate are heated while being heated. Pressure is applied for bonding (the tenth aspect of the present invention).

In addition, a printed circuit board of the present invention is formed using the copper clad laminate according to any one of the fifth to seventh aspects of the present invention (the eleventh aspect of the present invention).

The so-called T portion in the present invention is a copper clad laminate with treated copper foil on both sides (hereinafter, sometimes referred to as "double-sided copper clad laminate") or a copper clad laminate with treated copper foil on only one side (Hereinafter, it may be referred to as a "single-sided copper-clad laminate"), both of which refer to parts other than the processed copper foil residual part (1). Invention effect

Since the processed copper foil of the present invention does not have a roughened layer and the propagation distance of current is short, the transmission loss caused by the skin effect is small, and it can also be applied to printed circuit boards corresponding to high-speed/high-frequency transmission.

In addition, since the low-thickness untreated copper foil is provided with an anti-oxidation treatment layer showing a high chroma color, the copper clad laminate with a treated copper foil in the present invention has a lower HAZE value in the etched part because The remaining portion of the processed copper foil (wiring pattern portion) has a high chroma color. Therefore, even if it is photographed by a CCD camera, the boundary between the etching portion and the wiring pattern portion is obvious, and the visibility is excellent. Therefore, positioning and AOI inspection when installing ACF can be performed with high accuracy.

In addition, the color of the treated surface in the present invention is "high chroma" means that in the color system XYZ (Yxy) defined in JIS Z 8701, Y is in the range of 10-30, x is 0.24-0.31, and y is 0.29-0.33 The color is blue as seen by the naked eye.

Since the treated copper foil in the present invention is provided with an anti-oxidation treatment layer containing cobalt and molybdenum, the peel strength can be maintained even after heating or chemical impregnation, and it is also possible to suppress the penetration of the chemical impregnation.

If a chromate layer and/or a silane coupling agent layer are provided on the oxidation treatment layer, the peel strength can be further maintained even after heating or chemical immersion, and the penetration of chemical immersion can be further suppressed.

In addition, when the processed copper foil of the present invention and the insulating resin base material containing polyimide are bonded together, particularly strong peel strength can be achieved.

In addition, in the case of the treated copper foil of the present invention, even if the entire surface of the copper clad laminate having the treated copper foil provided on both sides of the insulating resin substrate is etched, the other surface is etched. When the wiring pattern part is formed by processing, the HAZE value of the T part can be made below 60%, and the L* of the color system L*·a*·b* defined by JIS Z 8781 is 88-100, a* For a single color in the range of -0.14 to 1.10 and b* of -0.13 to 15, the color difference E*ab between the T portion measured from the direction of the entire etched surface and the remaining portion of the processed copper foil can be 60 As described above, therefore, the boundary between the etching part and the wiring pattern part is clear, and positioning and AOI inspection at the time of ACF mounting using a CCD camera can be performed with high accuracy.

Mode for implementing the invention <Untreated copper foil> The copper foil before each treatment used in the present invention (hereinafter referred to as "untreated copper foil") is not particularly limited, and there is no difference between the rolled copper foil and the surface All electrolytic copper foils with differences in it can be used. Of course, the rolled copper foil can be on either side, and the electrolytic copper foil can be either the precipitation side or the glossy side. In addition, when a rolled copper foil is used, it is preferable to perform various treatments after immersing in a hydrocarbon-based organic solvent to remove the rolling oil.

Since the ten-point average roughness RzJIS94 of the treated surface of the treated copper foil in the present invention is 1.2 μm or less, the ten-point average roughness RzJIS94 of the surface of the untreated copper foil is also 1.2 μm or less.

The thickness of the untreated copper foil is not particularly limited as long as it can be used for a printed circuit board after surface treatment, but it is preferably 6 to 300 μm, and more preferably 9 to 300 μm. ＜Anti-oxidation treatment layer＞

The treated copper foil in the present invention is provided with an anti-oxidation treatment layer containing cobalt and molybdenum on the untreated copper foil.

The anti-oxidation treatment layer can be formed by coating an insoluble electrode such as titanium with a white metal oxide in an electrolytic bath containing a cobalt-containing compound and a molybdenum-containing compound and each having a concentration of 100g/L or less and adjusted to be alkaline. The anode is formed by immersing an untreated copper foil as a cathode, ^{and electrolyzing it under the conditions of a current density of 0.1 to 20 A/dm 2} , an electric quantity of 5 ^{to 50 C/dm 2} , and a liquid temperature of 20 to 50°C.

The cobalt-containing compound dissolved in the electrolytic bath is not particularly limited. For example, cobalt sulfate heptahydrate, cobalt ammonium sulfate, cobalt citrate, and cobalt acetate can be used.

The molybdenum-containing compound dissolved in the electrolytic bath is not limited, and examples include disodium molybdate dihydrate, sodium molybdate, potassium molybdate, and ammonium molybdate.

The electrolytic bath is adjusted to be alkaline. This is because if it is an acidic electrolytic bath, the color of the treated surface is in accordance with the color system XYZ (Yxy) defined by JIS Z 8701, which does not fall into the range of 10-30 for Y, 0.24-0.31 for x, and 0.29-0.33 for y. In addition, because the naked eye sees a light brown color that is difficult to obtain contrast with the polyimide resin substrate, it is difficult to distinguish the etching part from the processed copper foil residue (wiring pattern) when viewed through a CCD camera. Department).

There are no particular limitations on the substance added to adjust the alkalinity, but pyrophosphate is preferred. As the pyrophosphate, potassium pyrophosphate, sodium pyrophosphate, and calcium pyrophosphate can be exemplified.

The adhesion amount of the anti-oxidation treatment layer is preferably 150 to 300 mg/m ² , and more preferably 170 to 270 mg/m ² . Since the adhesion amount is less than 150 mg/m ² , the color with high chroma in the present invention will not appear. On the other hand ^{, when the adhesion amount exceeds 300 mg/m 2} , even if the adhesion amount is 300 mg/m ² or more The chroma does not change, the economy is poor, and the transmission characteristics tend to decrease, so it is not preferable.

The content of molybdenum contained in the anti-oxidation treatment layer is preferably 25 to 50% by weight, and more preferably 30 to 48% by weight. If the content of molybdenum is less than 25% by weight, the deterioration rate of the peel strength after the heat treatment and the chemical immersion treatment will increase, and the amount of penetration during the chemical immersion will also increase, which is not preferable. In addition, even if the molybdenum contained exceeds 50% by weight, further improvement in the degradation rate of the peel strength and the suppression effect of the penetration amount cannot be expected. ＜Chromate layer/Silicane coupling agent layer＞

In the treated copper foil of the present invention, a chromate layer and/or a silane coupling agent layer can be provided on the anti-oxidation treatment layer as required.

The chromate layer can be immersed in an electrolytic bath with an insoluble electrode such as titanium coated with white metal oxide as the anode and copper foil with an anti-oxidation treatment layer as the cathode. The liquid temperature is 20-50°C and the current density is 10A/ It can be formed by electrolysis under the conditions of dm ² or less and an electric quantity of 20 C/dm ² or less, or it can also be formed by only immersing in the solution.

Preferably, the electrolytic bath or immersion solution prepares a 3-50g/L aqueous solution containing a chromic acid compound to a pH of 2-12.

Examples of the chromic acid-containing compound include sodium dichromate dihydrate and chromic anhydride.

In addition, zinc may be contained in the chromate electrolytic bath.

A silane coupling agent layer can be provided on the chromate layer or on the anti-oxidation treatment layer.

The silane coupling agent used in the silane coupling agent layer is not particularly limited, and silane coupling agents containing vinyl, epoxy, styryl, methacryl, acrylic, amino, urea and mercapto groups can be used. , Silane coupling agents containing amino groups, epoxy groups or vinyl groups have very high hygroscopicity and rust prevention effects, and can be used more preferably.

The silane coupling agent may be used singly or in combination of two or more kinds.

It can be immersed in an aqueous solution of silane coupling agent prepared at a liquid temperature of 20-50°C, or dispersed by spraying methods.

The ten-point average roughness RzJIS94 of the treated surface of the treated copper foil in the present invention is preferably 1.2 μm or less, and more preferably 1.1 μm or less. This is because if it is larger than 1.2 μm, the HAZE value of the etched portion when the copper-clad laminate is formed will increase.

The color system XYZ (Yxy) of the treated surface can be measured with a spectral colorimeter. ＜Resin base material＞

Examples of the insulating resin substrate for laminating the treated copper foil of the present invention include polyimide resins, epoxy resins, polyphenylene ether resins, bismaleimide triazine resins, and cycloolefin polymer resins. The substrate. Since polyimide resin is excellent in heat resistance, chemical resistance, and flexibility, it is often used for flexible substrates.

In order to further suppress the transmission loss of the printed circuit board, a low-dielectric constant resin substrate can also be used. As the low dielectric constant resin substrate, resins containing liquid crystal polymers, polyvinyl fluoride, isocyanate compounds, and modified polyphenylene ethers can be exemplified. <HAZE value>

The HAZE value of the T portion of the double-sided copper-clad laminate and the single-sided copper-clad laminate can be measured with a haze meter in accordance with the provisions of JIS K 7136. ＜Color difference ΔE*ab＞

The color system L*a*b* defined in accordance with JIS Z 8781 (hereinafter referred to as "color system L*a") of the T part of a double-sided copper-clad laminate and a single-sided copper-clad laminate measured from the D direction through a colorimeter The value of *b*”) and the value of the residual part of the processed copper foil measured by the colorimeter from the D direction are substituted into the following formula to calculate. ΔE*ab=([ΔL*] ² +[Δa*] ² +[Δb*] ² ) ^1/2

Since the etched part is viewed through the color of the measuring table, it will affect the value of the color difference ΔE*ab. Therefore, in the present invention, the color of the measuring table is defined as the color system L*a*b*. L* is 88～ 100, a* is a single color in the range of -0.14 to 1.10, and b* is in the range of -0.13 to 15.

In addition, the color of the measuring table in the above range refers to a single color that belongs to the color range from white to milky white to the naked eye. As an example, the measured values of the color system L*a*b* of white copy paper, milky white test bench, and color difference meter standard plate are shown in Table 1.

實施例Table 1

Example

Examples of the present invention are shown below, but the present invention is not limited to these examples. (Untreated copper foil)

As the untreated copper foil of the Examples and Comparative Examples, an electrolytic copper foil having a thickness of 12 μm was used. The ten-point average roughness of the treated surface of the copper foil uses Surfcorder SE1700α (manufactured by Kosaka Laboratory Co., Ltd.) suitable for the stylus-type surface roughness measuring instrument specified in JIS B0651-2001. The stylus uses a stylus tip radius of 2μm. For the stylus, the ten-point average roughness RzJIS94 defined in JISB0601-1994 was measured with a cutoff value of 0.8mm for the roughness curve and a measuring distance of 4.0mm. (Examples 1～10)

In Examples 1 to 10, as shown below, an anti-oxidation treatment layer, a chromate layer, and a silane coupling agent layer were provided. <Anti-oxidation treatment layer> As shown in Table 2, the anode is used in an electrolytic bath containing cobalt (II) sulfate heptahydrate, molybdenum (VI) sodium dihydrate, potassium pyrophosphate, and adjusted pH and liquid temperature. Untreated copper foil was used for the surface of titanium covered with white metal oxide and the cathode. Similarly, under the electrolysis conditions described in Table 2, an anti-oxidation treatment layer containing cobalt and molybdenum was provided on the untreated copper foil. ＜Chromate layer＞

In the 40g/L aqueous solution of sodium dichromate dihydrate prepared into a chromate aqueous solution with a liquid temperature of 35°C and a pH of 4.0, platinum is used for the anode and each treated copper foil with an anti-oxidation treatment layer is used for the cathode. A chromate layer is provided on the anti-oxidation treatment layer under the electrolysis conditions of 0.5A/dm ² and electric quantity 1C/dm ^2. ＜Silane Coupling Agent Layer＞

Each treated copper foil provided with a chromate layer was immersed in an aqueous solution containing 5 ml/L of γ-aminopropyltriethoxysilane at a liquid temperature of 30°C for 10 seconds to provide a silane coupling agent layer. After providing the silane coupling agent layer, it was allowed to naturally dry at room temperature (about 25°C), and various measurements were performed on the treated copper foils of Examples 1-10. (Comparative example 1)

In Comparative Example 1, no anti-oxidation treatment layer was provided. The chromate layer and the silane coupling agent layer were provided by the same method as in the embodiment. (Comparative Examples 2～4)

As shown in Table 2, in the adjusted electrolytic bath, a treatment layer was also provided on the untreated copper foil under the conditions described in Table 2.

In addition, Comparative Example 2 uses sodium citrate instead of potassium pyrophosphate.

The chromate layer and the silane coupling agent layer are arranged in the same way as in the embodiment.

(Comparative Example 5)

In a solution adjusted to 15g/L copper sulfate pentahydrate, 8.5g/L cobalt sulfate heptahydrate, nickel sulfate hexahydrate 8.6, pH 2.5, and liquid temperature 38℃, the anode is coated with a white metal oxide. For titanium, a 12 μm untreated electrolytic copper foil with RzJIS94 of 0.75 μm was used for the cathode, and the cathode was electrolyzed at 45 A/dm ² for 1 second to form a roughened layer of copper-cobalt-nickel.

Next, use a solution adjusted to 10 g/L cobalt sulfate heptahydrate, 10 g/L nickel sulfate hexahydrate, pH 3.0, and a liquid temperature of 30°C. The anode uses titanium coated with a white metal oxide, and the cathode Using an electrolytic copper foil formed with a roughened layer of copper-cobalt-nickel ^{, cathode electrolysis was performed at 2 A/dm 2} for 5 seconds to form a cobalt-nickel alloy layer on the roughened layer.

After that, in a solution adjusted to zinc sulfate heptahydrate 150 g/L, pH 3.0, and liquid temperature 50 degrees, the anode uses titanium coated with white metal oxide, and the cathode uses cobalt on the roughened layer. The copper foil of the nickel alloy layer was ^{subjected to cathodic electrolysis at 0.5 A/dm 2} for 5 seconds to form a zinc layer.

The chromate layer and the silane coupling agent layer are provided by the same method as in the embodiment. After all the surface treatments were performed, when the roughness RzJIS94 was measured, it was 1.32 μm.

※1：比較例2使用檸檬酸鈉Table 2

※1: Comparative example 2 uses sodium citrate

The following measurements were performed on each processed copper foil. ＜Color system XYZ(Yxy)＞

With respect to the surface provided with each treatment layer, the color system XYZ (Yxy) defined in JIS Z8701 was measured using a spectral colorimeter CM-600d (manufactured by KONICA MINOLTA Co., Ltd.). ＜Amount of adhesion of anti-oxidation treatment layer＞

Using RIX2000 manufactured by Rigaku Electric Co., Ltd., the precipitation and adhesion amount of each element of cobalt and molybdenum in the oxidation prevention treatment layer was measured, and the sum of the two elements was defined as the adhesion amount. ＜Molybdenum content rate＞

The precipitation and adhesion amounts of cobalt and molybdenum elements obtained from the precipitation and adhesion amounts of the oxidation-preventing treatment layer were used, and the content rate (wt%) of each element was substituted into the following formula to calculate. Mo content rate (wt%) = {(Mo precipitation and adhesion amount)/(Co precipitation and adhesion amount + Mo precipitation and adhesion amount)}×100

table 3

Each processed copper foil was bonded to an insulating resin substrate to produce a copper-clad laminate, and each measurement was performed. ＜Copper clad laminate A＞

The surface provided with the treated layer of each treated copper foil was used as the bonded surface, and the polyimide resin substrate (product name: FRS-142, thickness 25μm) was applied using a vacuum hot press KVHC-II (manufactured by Kitagawa Seiki Co., Ltd.) , Kaneka Co., Ltd.) After preheating under vacuum (7torr) at a temperature of 260°C for 15 minutes, heating and pressurizing molding was performed under vacuum (7torr) at a temperature of 300°C and a pressure of 4MPa for 10 minutes. Thereafter, similarly, the copper foils of the respective treatments of the examples and the comparative examples were attached to the other side of the polyimide resin base material to produce the copper-clad copper foils of the embodiment and the comparative example in which the respective treated copper foils were bonded on both sides Laminate. The copper-clad laminate whose resin substrate is a polyimide resin substrate is called copper-clad laminate A.

Various measurements were performed in a state where the entire surface of the copper-clad laminate A was etched, and the other surface was etched only partially, and various processed copper foils remained in the remaining portion. <HAZE value>

The HAZE value of the T part of the copper clad laminate A was measured using a haze meter NDH7000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7136. ＜Color difference ΔE*ab＞

According to JIS Z 8730 as the standard. For each color system of the T part of the copper clad laminate A and the remaining part of the treated copper foil (1), after measuring the color system L*a*b* from the D direction using a spectral colorimeter CM-600d, substitute it The following formula is used as the value of ΔE*ab. ΔE*ab= ([ΔL*] ² +[Δa*] ² +[Δb*] ² ) ^1/2

The measurement of color difference is shown in the column of "Measuring Table" in Table 4. On white copy paper (L*=92.25, a*=0.38, b*=2.31) and milky white experimental table (L*=88.64, a*= 1.06, b*=13.49), color difference meter standard plate (L*=99.47, a*=-0.14, b*=-0.13).

In addition, each copper-clad laminate A prepared using the processed copper foils of Examples 3, 7, and 10 was measured on a copy paper, a milky white test stand, and a color difference meter standard plate, respectively, and the color difference ΔE*ab was compared. ＜Normal peel strength＞

Using an etching machine SPE-40 (manufactured by Ninomiya Systems Co., Ltd.), a copper circuit sample with a width of 1 mm was produced by etching. According to JIS C6481, the peel strength was measured using a universal testing machine. The normal peel strength is shown in the "Peeling" column of Table 4. <Deterioration rate of peel strength after heat treatment>

The sample on which the normal peel strength was measured was heat-treated under the conditions of a temperature of 150° C. for 240 hours using an air furnace, and then returned to normal temperature. Thereafter, the peel strength was measured. The degradation rate is calculated by the following formula. In addition, in the formula, α represents the value of the peel strength before the heat treatment (normal state), and β represents the value of the peel strength after the heat treatment. Deterioration rate (%)=(α-β)/α×100 The degradation rate of the peel strength after the heat treatment is shown in the "deterioration rate" column of Table 4. ＜Penetration amount＞

The copper circuit sample with a width of 1 mm was immersed in a 5 wt% sulfuric acid aqueous solution under the condition of a liquid temperature of 65±3° C. for 30 minutes. Next, after washing with water and drying, the copper circuit is peeled off from the copper clad laminate. Since the chromatic aberration occurs in the part that has penetrated the sulfuric acid aqueous solution, the peeled copper foil surface was observed with an optical microscope, and the penetration amount (μm) of the sulfuric acid aqueous solution was read by the chromatic aberration. ＜Visibility＞

The processed copper foil on either side of the copper-clad laminate A was completely etched, and a 50 μm×50 μm square (1) composed of each processed copper foil was formed on the other surface by etching. Place each copper-clad laminate A on any one of the white copy paper, the milky white laboratory bench or the color difference meter standard board with the quadrangle (1) facing downwards, and set the CCD line sensor camera PIE-550 (monochrome line The sensor, 5150 pixels (40MHz)/made by Ikegami Telecommunications Co., Ltd.) is installed 70mm away from the side where the entire surface of the copper-clad laminate A has been etched, and senses through the CCD line at 5m/min. 10 times below the camera (6), mark the case where the CCD line sensor camera can detect a 50μm×50μm square (1) 9 times or more as ◎, and mark the case where it can detect 7-8 times as ○ , Mark the case that can be detected 6 times as △, and mark the case that can only be detected 5 times or less as × for evaluation. In addition, the lighting uses metal halide lamps. ＜Transmission loss: Copper clad laminate A＞

Using an etching machine, a single-ended microstrip line is formed by etching. In addition, the circuit width of the present substrate is set to be 50 μm in width so that the characteristic impedance becomes 50 Ω. The produced circuit board was measured with a network analyzer (N5247A, manufactured by Agilent Technologies, Inc.) for its S parameter (S21) at a frequency of 160 MHz to 20 GHz. ＜Copper clad laminate B＞

On one side of a liquid crystal polymer resin substrate (product name: CT-Z, thickness 50μm, manufactured by Kuraray Co., Ltd.), the surface provided with the treated copper foils of the examples and comparative examples was used as the surface to be bonded Bonding, and bonding the copper foil (70μm) for the base on the other side, using a vacuum hot press KVHC-II to preheat it under vacuum (7torr) at a temperature of 260°C for 15 minutes, and then under vacuum (7torr), A temperature of 300° C. and a pressure of 4 MPa were heated and pressed for 10 minutes to obtain a copper-clad laminate. The copper-clad laminate in which the resin substrate is a liquid crystal polymer resin substrate is referred to as a copper-clad laminate B. ＜Transmission loss: Copper clad laminate B＞

Using an etching machine, a single-ended microstrip line is formed by etching. In addition, the circuit width of this substrate is set to 110 μm in the case of a liquid crystal polymer resin base material (manufactured by Kuraray Co., Ltd., product name: CT-Z, thickness 50 μm) so that the characteristic impedance becomes 50 Ω. In the case of an amine resin substrate (manufactured by Kaneka Co., Ltd., product name: FRS-142, thickness 25 μm), the width is set to 50 μm. The S parameter (S21) of the produced circuit board with a frequency of 160MHz to 40GHz was measured using a network analyzer.

The types of copper-clad laminates on which the respective measurements were performed are shown in the column of "Measured laminates" in Table 4.

※測定台 a 複印紙 b 實驗台 c 色差計標準板Table 4

※Measuring table a Copy paper b Experiment table c Color difference meter standard board

table 5

As shown in Table 4, it is shown that the copper clad laminate with the treated copper foil of the present invention is a laminate that maintains high peel strength under normal conditions and after heating. In addition, there is no penetration of chemicals, and the HAZE value of the etching part In addition, as shown in Table 3, since the processed surface of the processed copper foil of the present invention exhibits a high chroma color, the color difference ΔE*ab between the etched part and the remaining part of the processed copper foil is 60 or more, and the visibility is very excellent Therefore, the detection of the camera using the CCD line sensor becomes easy, and the transmission loss is small.

In addition, it can be confirmed that, as shown in Table 5, the ΔE*ab calculated by measuring the same sample on a copy paper, a milky white laboratory bench, or a color difference meter standard plate is 60 or more. Industrial availability

The copper-clad laminate provided with the treated copper foil of the present invention becomes a laminate: Needless to say, high peel strength is ensured even after heating or chemical impregnation, and transmission loss is small. Therefore, it is suitable for high-speed applications. /High-frequency transmission printed circuit board. In addition, since the HAZE value of the etching part is low, the boundary between the etching part and the wiring pattern part is clear, and the visibility is excellent. Therefore, it is possible to accurately perform alignment using a CCD camera and AOI inspection. Therefore, the present invention is an invention with high industrial applicability.

1‧‧‧Processing copper foil residue (wiring pattern part)2‧‧‧Insulating resin base material 3a‧‧‧Full-surface etching part 3b‧‧‧Etching part4‧‧‧Copper clad laminate 5‧‧‧sets 6‧‧‧CCD camera

Fig. 1 is a schematic diagram of a copper clad laminate after etching. Figure 2 is a schematic diagram when using a CCD camera.

1‧‧‧Handle the remaining copper foil (wiring pattern)

2‧‧‧Insulating resin substrate

3a‧‧‧Entire etching part

3b‧‧‧Etching

Claims (11)

A treated copper foil for a copper-clad laminate, which is provided with an anti-oxidation treatment layer on at least one surface of an untreated copper foil surface, the anti-oxidation treatment layer contains cobalt and molybdenum, and the anti-oxidation treatment is performed on ten The point average roughness RzJIS94 is 1.2μm or less (not including 0μm), wherein, in the color system XYZ (Yxy) defined in JIS Z 8701 of the treated surface, Y is 10-30, x is 0.24~0.31, and y is 0.29~0.33, and the electrolytic bath forming the anti-oxidation treatment layer is an alkaline electrolytic bath containing cobalt and molybdenum. The treated copper foil for a copper-clad laminate according to claim 1, wherein the content of molybdenum contained in the anti-oxidation treatment layer is 25 to 50% by weight. The treated copper foil for a copper-clad laminate according to claim 1 or 2, wherein the anti-oxidation treatment layer is provided with a chromate layer and/or a silane coupling agent layer. The processed copper foil for a copper-clad laminate according to claim 1, wherein the entire surface of either side of the copper-clad laminate on which the processed copper foil is attached to both surfaces of an insulating resin substrate is etched and In the copper clad laminate in which the other side is partially etched, or in the copper clad laminate in which the processed copper foil is attached to only one side of the insulating resin substrate and the processed copper foil is partially etched, the following T The HAZE value of the part is 60% or less, and from the following D direction according to the color system L*‧a*‧b* defined by JIS Z 8781, L* is 88~100, a* is -0.14~1.10, b* is -The T part of the color system L*‧a*‧b* measured on a single color in the range of 0.13~15 and the treated copper The color difference E*ab of the remaining part of the foil is 60 or more, T part: the copper clad laminate with the treated copper foil on both sides is the part where both sides are etched, and the copper clad laminate with the treated copper foil on only one side is Part to be etched; D direction: The copper clad laminate with the treated copper foil on both sides is the direction of the surface where the entire surface is etched, and the copper clad laminate with the treated copper foil on only one side is equipped with the treated copper foil The opposite direction of the face. A copper-clad laminate, wherein the treated copper foil for a copper-clad laminate according to any one of claims 1 to 4 is attached to at least one surface of an insulating resin substrate. The copper-clad laminate according to claim 5, wherein the entire surface of either side of the copper-clad laminate on which the treated copper foil is attached to both sides of the insulating resin substrate is etched and the other side is partially etched A copper clad laminate that has been etched ground or a copper clad laminate in which the processed copper foil is attached to only one side of an insulating resin substrate and a part of the processed copper foil is etched, the HAZE value of the T part below It is 60% or less, and from the following D direction in accordance with the color system L*‧a*‧b* defined by JIS Z 8781, L* is 88~100, a* is -0.14~1.10, b* is -0.13~15 The color difference E*ab between the T part of the color system L*‧a*‧b* and the remaining part of the treated copper foil measured on a single color in the range of the color system is 60 or more. T part: The treated copper foil is provided on both sides The copper-clad laminate is the part where both sides are etched, and the copper-clad laminate with the treated copper foil on only one side is the etched part; D direction: the copper-clad laminate with the treated copper foil on both sides is aligned The direction of the etched surface, and the copper-clad laminate provided with the processed copper foil on only one surface is the opposite direction of the surface provided with the processed copper foil. The copper clad laminate according to claim 5 or 6, wherein the insulating resin substrate is a resin substrate containing a polyimide compound. A method for manufacturing a treated copper foil for a copper-clad laminate according to any one of claims 1 to 4, wherein the anti-oxidation treatment layer is formed by an alkaline electrolytic bath containing cobalt and molybdenum. The method for producing a treated copper foil for a copper-clad laminate according to claim 8, wherein the alkaline electrolytic bath is an electrolytic bath containing pyrophosphoric acid. A method for manufacturing a copper-clad laminate according to any one of claims 5 to 7, characterized in that the processed copper foil for a copper-clad laminate and an insulating resin base material are heated and pressurized for bonding. A printed circuit board formed by using the copper clad laminate according to any one of claims 5 to 7.

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