JP2010236058A - Roughening-processed copper foil, method of manufacturing roughening-processed copper foil and copper clad laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low profile copper foil having improved adhesiveness of an electrolytic copper foil with a resin base material such as a liquid crystal polymer having excellent heat resistance and high frequency characteristics and capable of being used for a stabilized copper clad laminate manufacture. <P>SOLUTION: In the roughening processed copper foil provided with a roughened surface formed by depositing fine copper particle on the surface of the copper foil, the roughening processed copper foil includes projecting shaped fine copper particles 2 each having ≤85° top angle θ to form the roughened surface. In the roughening processed copper foil having the roughened surface formed by the deposition of the fine copper particles on the surface of the copper foil by an electrolysis using a copper sulfate base copper electrolyte to manufacture the copper foil, a copper electrolytic solution having a prescribed composition containing one of formamidine disulfide and thiourea is preferably used as the copper sulfate based copper electrolytic solution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a roughened copper foil and a method for producing a roughened copper foil. In particular, it is related with copper foil provided with the roughening process surface excellent in adhesiveness with the liquid crystal polymer base material used for printed wiring board manufacture.

  Conventionally, electrolytic copper foil and rolled copper foil have been widely used for the production of printed wiring boards. These copper foils for printed wiring boards are used by being bonded to an insulating resin base material typified by epoxy resin, polyimide resin or the like. Therefore, a roughened surface has been formed by depositing fine copper particles on the bonding surface of a copper foil, which is a metal material. When the copper foil and the insulating resin base material are bonded together, the fine copper particles on the surface of the copper foil are embedded in the resin and exhibit an anchoring effect for improving adhesion.

  In the case of conventional electrolytic copper foil, as shown in FIG. 4, fine copper particles are deposited and formed on the mountain-shaped protrusions that the electrolytic copper foil inevitably has, and this is required depending on the use such as rust prevention treatment. Has been subjected to surface treatment. These have been mainly used for rigid printed wiring boards as roughened copper foils for printed wiring boards. For example, Patent Document 1 provides a copper foil that maximizes the performance of a silane coupling agent used for the purpose of increasing the adhesive strength between the copper foil used for the production of a printed wiring board and the base material, and a method for producing the copper foil. Discloses a surface-treated copper foil. The surface-treated copper foil referred to here is the same as the image observed by the scanning electron microscope shown in FIG. 4 in this specification, as can be understood from FIGS. 2 and 4 shown as schematic diagrams in Patent Document 1. It can be classified into forms. However, if the roughened surface of the copper foil with the insulating resin is roughened as shown in FIG. 4 and there are significant irregularities, it is difficult to form the fine pitch circuit currently required. Therefore, a low profile copper foil with less unevenness on the bonding surface of the copper foil has been desired.

  On the other hand, the rolled copper foil is a low-profile copper foil with less unevenness on the bonding surface of the copper foil because a rough surface like the electrolytic copper foil is not formed in the manufacturing process. Therefore, it has been widely used in applications that require the formation of a fine pitch circuit compared to rigid printed wiring boards. In particular, in the field of flexible printed wiring boards, the use of electrolytic copper foil whose surface is unavoidably formed during the manufacturing process has been avoided, and rolled copper foil has been used historically. The shape of the roughened surface of the rolled copper foil is, for example, as shown in the schematic diagram shown in FIG.

  However, in the market, demands for downsizing, weight reduction, high functionality and the like of electric and electronic devices using printed wiring boards have become prominent. As a result, the formation of fine pitch circuits is also required for rigid printed wiring boards, and the low profile of the bonded surface of the electrolytic copper foil with the insulating resin base material, which is superior in cost performance to the rolled copper foil. Therefore, the low profile electrolytic copper foil as disclosed in Patent Literature 3 and Patent Literature 4 is provided, and the roughness of the bonding surface of the electrolytic copper foil approaches that of the rolled copper foil. ing.

  And in recent years, as disclosed in Patent Document 6 and Patent Document 7, it is required to use copper foil in combination with a new insulating resin base material, from the viewpoint of ensuring good high-frequency characteristics, Here, the tendency to use low profile electrolytic copper foil is increasing.

  Patent Document 6 discloses a high-frequency print capable of manufacturing a copper-clad laminate in which a liquid crystal polymer film having a low hygroscopic property and having a solder heat resistance at high temperatures and a copper foil are laminated, and a fine pattern can be formed thereon. As a copper foil for a wiring board, a roughening treatment layer made of spherical fine roughening particles having a diameter of 0.05 to 1.0 μm is applied to at least one surface of the copper foil, and further on the roughening treatment layer A heat-resistant / rust-proof layer composed of at least one of molybdenum, nickel, tungsten, phosphorus, cobalt, and germanium is applied, and a chromate film layer is further formed on the heat-resistant / rust-proof layer, and further on the chromate film layer. What is characterized by applying a silane coupling agent layer is disclosed.

  In Patent Document 7, it is possible to obtain a strong peeling strength against a high-frequency substrate typified by a PPE resin-impregnated base material, and after forming a circuit pattern by etching by making the roughness of the rough surface extremely low. A copper foil for a high-frequency printed wiring board capable of improving the linearity of the circuit bottom line and reducing transmission loss is disclosed, and “the surface roughness Rz: 2 is attached to at least one surface of the copper foil. A surface-treated copper foil having a roughened surface with a lightness value of 25 or less, and an insulating substrate composed of 50% or more of a thermoplastic liquid crystal polymer are laminated. The composite material for the substrate to be used. "

JP 2001-177204 A JP 2008-86999 A Japanese Patent Laid-Open No. 07-231152 JP 2004-263289 A Japanese Patent No. 4065004 JP 2006-210689 A JP 2005-219379 A

  However, the bonded surface of the low profile electrolytic copper foil used in the above-mentioned Patent Documents 3 to 7 with the insulating resin base material is the fine copper used for the roughening treatment of the conventional rolled copper foil. Similar to the particle shape of the particles, it has a shape that can be referred to as a substantially spherical shape.

  Even if the substantially spherical fine copper particles are deposited on the low profile surface of the electrolytic copper foil, the resin component of the resin base material to be bonded is a liquid crystal polymer, polyphenylene oxide resin (PPO), polyphenylene ether resin (PPE), In the case of a resin excellent in high heat resistance and high-frequency characteristics such as cycloolefin polymer (COP), the adhesion between the electrolytic copper foil and the resin base material varies, or there is a practically usable level of adhesion. Many cases were not obtained.

  And in order to improve the adhesiveness of electrolytic copper foil and the said resin base material, like patent document 6, the component of the antirust process layer provided in the surface of a roughening process is examined, or a silane coupling agent Although a technique such as processing is conceivable, there is a limit to the known technique.

  From the above, there has been a demand in the market for a new low-profile copper foil that can improve the adhesion between the electrolytic copper foil and the resin base material and can be used for the production of a stabilized copper-clad laminate.

  Therefore, as a result of diligent research, the inventors of the present invention, as shown below, have improved the adhesion between an electrolytic copper foil having a low profile bonding surface and an insulating resin base material that can be used in high frequency applications. The shape of the fine copper particles deposited on the roughened surface of the low profile electrolytic copper foil is as described below, so that the roughened particles can be easily removed by etching, and the high heat resistance and The inventors have conceived that sufficient adhesion can be secured with an insulating resin base material that can be used in high frequency applications.

Roughened copper foil according to the present invention: The roughened copper foil according to the present invention is a roughened copper foil provided with a roughened treated surface in which fine copper particles are deposited on the surface of the copper foil. The treatment surface includes protrusion-shaped fine copper particles having a vertex angle of 85 ° or less.

Manufacturing method of roughening copper foil which concerns on this invention: The manufacturing method of the roughening copper foil which concerns on this invention made the fine copper particle precipitate on the surface of copper foil using the copper sulfate type | system | group copper electrolyte solution. It is a manufacturing method of the roughening process copper foil provided with a roughening process surface, Comprising: As a copper sulfate type | system | group copper electrolyte solution used for formation of the said fine copper particle, copper concentration is 20g / l-50g / l, and sulfuric acid concentration is 25g / It is characterized by using one having a composition of 1 to 100 g / l, a formamidine disulfide concentration of 0.1 mmol / l to 0.3 mmol / l, and a chlorine concentration of 25 mg / l to 80 mg / l.

  Moreover, the manufacturing method of the roughening copper foil which concerns on this invention is using the copper sulfate type | system | group copper electrolyte solution, The roughening copper foil provided with the roughening processing surface which made the fine copper particle precipitate on the surface of copper foil As a copper sulfate-based copper electrolyte used for forming the fine copper particles, the copper sulfate pentahydrate (as copper) concentration is 20 g / l to 50 g / l, and the sulfuric acid concentration is 25 g / l. A composition having a composition of ˜100 g / l, a thiourea concentration of 0.2 mmol / l to 0.6 mmol / l, and a chlorine concentration of 20 mg / l to 130 mg / l is used.

Copper-clad laminate according to the present invention: The copper-clad laminate according to the present invention is obtained using the above-mentioned roughened copper foil.

  Since the roughened copper foil according to the present invention has a low profile surface roughened with fine copper particles having an unprecedented shape, the resin base material to be bonded is a liquid crystal polymer, polyphenylene oxide resin (PPO), polyphenylene ether. Even if the resin (PPE), cycloolefin polymer (COP), etc. are excellent in heat resistance and high frequency characteristics, the adhesion between the electrolytic copper foil and the resin substrate is stabilized at a level that does not impede practical use. The Therefore, by using the roughened copper foil according to the present invention, it is possible to manufacture a high-quality copper-clad laminate. Furthermore, by using this copper-clad laminate, it is possible to produce a printed wiring board having excellent high heat resistance and high frequency characteristics.

  Moreover, the method for producing a roughened copper foil according to the present invention uses a copper sulfate-based copper electrolyte containing a thiourea-based additive that has been said to be difficult to use in the production of an electrolytic copper foil. . By employ | adopting such a manufacturing method, the roughening process copper foil which concerns on this invention can be manufactured efficiently.

It is a schematic diagram of the shape of the fine copper particle which comprises the roughening process surface of a roughening process copper foil. It is a scanning electron microscope observation image of the roughening process layer which consists of the fine copper particle formed by precipitation on the copper foil surface (Example 1). It is a scanning electron microscope observation image of the roughening process layer which consists of the fine copper particle formed by precipitation on the copper foil surface (Example 2). It is a scanning electron microscope observation image showing the form of the roughening process formed by precipitation on the surface of a normal rolled copper foil.

  Embodiments relating to the roughened copper foil according to the present invention and the method for producing the same will be described.

Form of roughened copper foil according to the present invention: The roughened copper foil according to the present invention is a roughened copper foil provided with a roughened surface on which fine copper particles are deposited on the surface of the copper foil. The copper foil used here includes all of electrolytic copper foil and rolled copper foil, and there is no particular limitation regarding thickness and surface roughness. However, as for the fine copper particles constituting the roughened surface of the roughened copper foil according to the present invention, it is most preferable to use a low profile copper foil having a surface roughness (Rzjis) of 2.0 μm or less for forming the roughened surface. preferable.

  The fine copper particles constituting the roughened surface of the roughened copper foil according to the present invention are characterized in that those having a protrusion shape with a top angle of 85 ° or less are included. In FIG. 1, the shape of the fine copper particle 2 which comprises this roughening process surface is shown typically. FIG. 1 shows an ideal protrusion shape on the left side. However, only the top of the top of the fine copper particles 2 may be observed as the protrusion shape when observing with a scanning electron microscope. Accordingly, as shown in the enlarged view of the tip on the right side of FIG. 1, a contact point is defined at the ridge line at the substantially central portion of the height of the protrusion shape of the fine copper particles 2 that can be observed with the scanning electron microscope. The angle formed by the tangent line “a” and the “tangent line b” will be referred to as a “top angle”. The roughened copper foil according to the present invention includes a protrusion having a fine copper particle with a head-top angle of 85 ° or less, thereby sufficiently exhibiting an anchor effect for a resin excellent in high heat resistance and high frequency characteristics. It is. Here, when the vertex angle θ exceeds 85 °, it is not preferable since the anchor effect for the resin excellent in high heat resistance and high frequency characteristics is not obtained. The upper limit of the top angle θ is more preferably 80 °, and most preferably 75 ° or less. On the other hand, if the vertex angle θ is 85 ° or less, the above-described effects can be practically exhibited, and the lower limit is not particularly limited. However, if the top angle θ is too small, the tip of the fine copper particles will be excessively sharpened, and the tip will be easily deformed by rubbing, resulting in unstable anchoring effect on the resin having high heat resistance and high frequency characteristics. In addition, current concentration occurs when electrodepositing a rust-preventing component such as zinc or zinc alloy by an electrolytic method, and there is a tendency for the rust-preventing component to concentrate and precipitate at the tip of fine copper particles. Therefore, in order to obtain more stable quality, the lower limit of the top angle θ is preferably 5 ° or more, particularly 8 ° or more.

And it is preferable that the roughening process surface of the roughening copper foil which concerns on this invention is 0.05 piece / micrometer < ² > or more of protrusion-shaped fine copper particles whose top part angle is 85 degrees or less. When the number of fine copper particles is less than 0.05 particles / μm ² , the anchor effect when the roughened copper foil and the resin base material are bonded to each other is reduced, and the adhesiveness is lowered. More preferably, the number of protrusion-shaped fine copper particles having a vertex angle of 85 ° or less is 0.1 / μm ² or more. This is because the adhesion stability when the roughened copper foil and the resin base material are bonded to each other tends to be drastically improved. Here, although the upper limit is not particularly defined, it is preferably 0.6 / μm ² or less in consideration of the ability to form a fine pitch circuit by etching.

  Next, when the roughened surface of the roughened copper foil according to the present invention is measured using a color difference meter, a value in a certain range described below is shown. Therefore, the value of the color difference meter can be used as an alternative index for determining whether or not the fine copper particles having the above-described shape are deposited in a good state on the surface of the copper foil. In the present invention, a spectroscopic color difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd. was used for the color difference measurement.

The L ^* a ^* b ^* color system is used to display the color difference of the roughened surface of the roughened copper foil according to the present invention. This L ^* a ^* b ^* color system is the most widely used color system for representing the color of an object. It was standardized by the International Commission on Illumination (CIE) in 1976, and is a Japanese JIS standard. However, it is standardized as JIS Z 8729. In this ^L * ^a * ^{b *} color system, it represents lightness ^{L *,} which represent the chromaticity indicating the hue and saturation ^a * in ^{the L} * ^a * ^{b *} color system chromaticity diagram, in ^{b *} It is.

The roughened surface of the roughened copper foil according to the present invention is preferably in a predetermined color difference range such that the L ^* value measured by a color difference meter is 45 to 67. In the L ^* a ^* b ^* color system chromaticity diagram, becomes brighter shades the ^{L *} value increases, the dark tones higher ^{L *} value closer to 0. When the L ^* a ^* b ^* color system L ^* value when the roughened surface is measured is less than 45, the fine copper particles constituting the roughened surface of the roughened copper foil are excessive. If the resin base material to be bonded is a resin excellent in the above-described high heat resistance and high-frequency characteristics, a sufficient anchor effect cannot be obtained, which is not preferable. On the other hand, when the L ^* value of the L ^* a ^* b ^* color system when measuring the roughened surface is greater than 67, the fine copper particles constituting the roughened surface of the roughened copper foil Since the existence density of the fine copper particles that are coarsened or formed by precipitation decreases, a sufficient anchoring effect can be obtained when the resin base material to be bonded is a resin excellent in the above-mentioned high heat resistance and high frequency characteristics. It is not preferable because it disappears.

The roughened surface of the roughened copper foil according to the present invention preferably has an a ^* value of 19 to 35 in the L ^* a ^* b ^* color system as measured with a color difference meter. If this a ^* value is out of the range of 19 to 35, the adhesiveness in the case of bonding to the resin base material excellent in the above-mentioned high heat resistance and high frequency characteristics tends to vary, and the roughening treatment of the roughened copper foil It is considered that the fine copper particles constituting the surface are not in an appropriate shape.

Further, the roughened surface of the roughened copper foil according to the present invention has a b ^* value of 18 to 33 in the L ^* a ^* b ^* color system when the roughened surface is measured with a color difference meter. It is preferable. If this b ^* value is out of the range of 18 to 33, as in the case of the appropriate range of the a ^* value, there will be variations in the adhesion when pasted on the resin base material having the above-mentioned high heat resistance and high frequency characteristics. It becomes easy, and it is thought that the fine copper particle which comprises the roughening process surface of a roughening copper foil is not an appropriate shape.

And since the a ^* value and b ^* value of the above-mentioned L ^* a ^* b ^* color system exist on the same plane, originally, the a ^* value is 19 to 35, and b ^*. Most preferably, the value is 18 to 33. In fact, in the research up to the completion of the present invention, compared with the roughened copper foil that satisfies any one of the conditions of a ^* value of 19 to 35 and b ^* value of 18 to 33, It has been found that the roughened copper foil having the conditions exhibits stable adhesion to the insulating resin base material. Furthermore, the roughened copper foil satisfying all of the L ^* value, a ^* value, and b ^* value of the L ^* a ^* b ^* color system may exhibit the most stable adhesion to the insulating resin substrate. It turns out.

  Moreover, it is preferable that the value of 10-point average roughness (Rzjis) obtained when the said roughening process surface of the roughening process copper foil which concerns on this invention is measured is 0.6 micrometer-4.2 micrometers. In other words, it can be considered as an index proportional to the height of the fine copper particles constituting the roughened surface of the roughened copper foil. When the value of the 10-point average roughness (Rzjis) is less than 0.6 μm, the top of the fine copper particles constituting the roughened surface of the roughened copper foil has a protrusion shape with a top angle of 85 ° or less. Even in this case, it is not possible to obtain a good anchor effect for the resin base material having excellent high heat resistance and high frequency characteristics as described above, and good adhesion cannot be obtained. On the other hand, when the value of the 10-point average roughness (Rzjis) exceeds 4.2 μm, when the copper-clad laminate is used, the fine copper particles deeply penetrate into the base resin. Considering that the over-etching time set at the time of circuit formation by etching becomes longer, it is not preferable because it becomes a roughened copper foil that is not suitable for forming a fine pitch circuit and the productivity of etching processing is lowered. The 10-point average roughness (Rzjis) is more preferably 0.7 μm to 3.2 μm.

  In the roughened copper foil according to the present invention, the surface roughness is a value measured using a Zygo interferometer (Zygo New View 5032) using the interference action of white light in grasping the roughened state of the surface. Used. The measurement conditions when using this Zygo interferometer are a Mirau type with a 50 × objective lens, a numerical aperture (N / A) of 0.55, a range of 144 × 108 μm, and a measurement reproducibility of 0.1 nm in RMS.

  Moreover, it is preferable that the value of the specific surface area obtained when the said roughening process surface of the roughening process copper foil which concerns on this invention is measured is 1.05-3.40. This specific surface area is an index proportional to the deposition density of fine copper particles deposited on the copper foil surface. When the value of the specific surface area is less than 1.05, the precipitation density of the fine copper particles deposited on the copper foil surface is not appropriate, or the shape of the fine copper particles is excessive. There is a tendency, it is not possible to obtain a good anchor effect for a resin base material having high heat resistance and high frequency characteristics, and adhesion between the laminated roughened copper foil and the base material is in the same plane This is not preferable because of variations. When the value of the specific surface area exceeds 3.40, the shape of the fine copper particles tends to be excessively fine, or the fine copper particles are excessively deposited on the copper foil surface. This is not preferable because the fine copper particles deposited and formed on the surface of the copper foil easily fall off. More preferably, the value of the specific surface area is 1.10 to 3.00.

This specific surface area uses the value measured about the area | region whose two-dimensional surface area is 6550 micrometers ² using the ultra-deep color 3D shape measuring microscope (Keyence Co., Ltd. VK-9500, using the violet laser of visible light limit wavelength 408nm). Calculated.

  The roughened copper foil described above is at least one surface treatment of a rust-proofing layer and a silane coupling agent-treated layer on the surface of the roughened copper foil (including the roughened surface and its opposite surface). It is preferable to provide a layer from a practical viewpoint such as ensuring long-term storage stability, further improving adhesion with the base resin, improving chemical resistance, and improving moisture absorption resistance. There are no particular limitations on the types of the antirust treatment layer and the silane coupling agent treatment layer referred to here, and any insulating resin base material or printed wiring board to be used may be used. For example, an organic rust preventive film using an organic agent capable of forming a monomolecular film such as benzotriazole or imidazole may be used, or an inorganic rust preventive film such as zinc or zinc alloy having a sacrificial anticorrosive action may be used. Moreover, regarding the kind of silane coupling agent used for forming the silane coupling agent treatment layer, an epoxy silane coupling agent, an amino silane coupling agent, a mercapto silane coupling agent, and the like can be used.

Production form of roughened copper foil according to the present invention: The method for producing a roughened copper foil according to the present invention is a roughening process in which fine copper particles are formed on the surface of the copper foil using a copper sulfate-based copper electrolyte. In the manufacturing method of the roughening copper foil provided with a process surface, it is preferable to employ | adopt one of the solution compositions described below as a copper sulfate type | system | group copper electrolyte solution used for formation of the said fine copper particle. Hereinafter, the copper sulfate-based copper electrolyte solution 1 and the copper sulfate-based copper electrolyte solution 2 will be described separately.

[Copper sulfate-based copper electrolyte 1]
The copper sulfate-based copper electrolyte 1 basically has the following solution composition. The feature of this copper sulfate-based copper electrolyte 1 is that it contains formamidine disulfide, and it is particularly preferable to employ the following predetermined electrolytic conditions. The optimum conditions when using the copper sulfate-based copper electrolyte solution 1 are listed below.

Copper concentration: 20 g / l to 50 g / l
Sulfuric acid concentration: 25 g / l to 100 g / l
Formamidine disulfide concentration: 0.1 mmol / l to 0.3 mmol / l
Chlorine concentration: 25 mg / l to 80 mg / l
Solution temperature: 45 ° C-58 ° C
Current density: 35 A / dm ^{2 to} 60 A / dm ²

  First, the formamidine disulfide used as an additive will be described. The formamidine disulfide concentration is preferably in the range of 0.1 mmol / l to 0.3 mmol / l. This formamidine disulfide has a structural formula shown in the following chemical formula 1 and is a compound corresponding to a dimer of thiourea.

  By containing this formamidine disulfide in the copper sulfate-based copper electrolyte, the copper foil surface is efficiently precipitated and formed into fine copper particles with protrusions with a head angle of 85 ° or less. A surface can be formed. When the formamidine disulfide concentration is less than 0.1 mmol / l, the top angle of the fine copper particles deposited on the surface of the copper foil tends to be less than 85 °, which is not preferable. On the other hand, when the formamidine disulfide concentration exceeds 0.3 mmol / l, the top angle of the fine copper particles deposited on the surface of the copper foil tends to be less than 85 °, and at the same time, a roughened surface with excessive hardness. Therefore, the flexibility of the roughened copper foil is impaired, which is not preferable. Hereinafter, other components of the copper sulfate-based copper electrolyte 1 will be described.

  The copper concentration is in the range of 20 g / l to 50 g / l. When the copper concentration is less than 20 g / l, the deposition of fine copper particles on the surface of the copper foil is not uniform, and the local variation becomes large. On the other hand, when the copper concentration exceeds 50 g / l, the copper concentration in the solution approaches the smooth plating condition, and it is not preferable because burn plating that forms fine copper particles using a low current becomes difficult.

  The sulfuric acid concentration is in the range of 25 g / l to 100 g / l. This sulfuric acid concentration is determined in relation to the above-mentioned copper concentration in consideration of the intended use of the copper sulfate-based copper electrolyte. When the sulfuric acid concentration is less than 25 g / l in this copper sulfate-based copper electrolyte 1, it is not preferable because it lacks stability as a solution for forming fine copper particles under burn plating conditions and the solution life is shortened. On the other hand, when the sulfuric acid concentration exceeds 100 g / l, since the relative copper concentration is lowered, precipitation of fine copper particles on the surface of the copper foil is not preferable.

  Furthermore, the chlorine concentration is preferably in the range of 25 mg / l to 80 mg / l. When the chlorine concentration is less than 25 mg / l, the precipitation of fine copper particles on the copper foil surface becomes unstable, the precipitation state of the fine copper particles becomes uneven, and it becomes difficult to form good fine copper particles, which is not preferable. . On the other hand, when the chlorine concentration exceeds 80 mg / l, the formation of fine copper particles is easy, but the stability of the shape of the fine copper particles is impaired. Therefore, it is not preferable.

  The copper sulfate-based copper electrolyte 1 described above is preferably used at a solution temperature in the range of 45 ° C to 58 ° C. When the solution temperature is lower than 45 ° C., it is difficult to quickly form good fine copper particles, which is not preferable. On the other hand, when the solution temperature exceeds 58 ° C., moisture evaporation becomes significant, the solution composition changes rapidly, and the solution life is shortened, which is not preferable.

Furthermore, when using the copper sulfate-based copper electrolyte 1, it is preferable that the current density is in the range of 35 A / dm ^{2 to} 60 A / dm ² to deposit fine copper particles. When the current density is less than 35 A / dm ² , it is difficult to form good fine copper particles, and at the same time, industrially required productivity is not satisfied. On the other hand, when the current density exceeds 60 A / dm ² , the formation of the fine copper particles becomes easy, but it is difficult to make the size of the fine copper particles to be deposited and uniform, and a good roughened surface. This is not preferable because it cannot be formed.

[Copper sulfate-based copper electrolyte 2]
The copper sulfate-based copper electrolyte 2 is basically provided with the following solution composition. The feature of the copper sulfate-based copper electrolyte 2 is that it is a solution that suppresses the generation of sludge due to thiourea despite containing a predetermined amount of thiourea. And it is especially preferable to employ | adopt the predetermined electrolysis conditions shown below. The optimum conditions when using the copper sulfate-based copper electrolyte 2 are listed below.

Copper concentration: 20 g / l to 50 g / l
Sulfuric acid concentration: 25 g / l to 100 g / l
Thiourea concentration: 0.2 mmol / l to 0.6 mmol / l
Chlorine concentration: 20 mg / l to 130 mg / l
Solution temperature: 45 ° C-58 ° C
Current density: 35 A / dm ^{2 to} 75 A / dm ²

  In the copper sulfate-based copper electrolyte 2, the overall composition balance of the solution is important, but thiourea that has not been added to the solution used for the normal copper foil roughening treatment is used as an additive. Yes.

  When this thiourea is used as an additive for a copper sulfate-based copper electrolyte, it is considered that the reaction shown in Chemical Formula 2 occurs in the solution. Therefore, it is apparent that thiourea is added to the copper sulfate-based copper electrolyte, but it is considered that a certain amount of the formamidine disulfide is contained in the solution. Therefore, when thiourea is added alone and used, it must be added so as to have a higher concentration than the above-mentioned formamidine disulfide concentration with respect to the copper sulfate-based copper electrolyte. Furthermore, the copper sulfate-based copper electrolytic solution can promote the reaction shown in Chemical Formula 2 by pre-energizing the copper sulfate-based copper electrolytic solution before collecting the electrolytic copper foil as a product. Therefore, it is preferable to perform preliminary energization for the copper sulfate-based copper electrolyte.

  The thiourea concentration of the copper sulfate-based copper electrolyte 2 is preferably in the range of 0.2 mmol / l to 0.6 mmol / l. When the thiourea concentration is less than 0.2 mmol / l, the top angle of the fine copper particles deposited on the surface of the copper foil tends to be less than 85 °, which is not preferable. On the other hand, when the thiourea concentration exceeds 0.6 mmol / l, the top angle of the fine copper particles deposited on the surface of the copper foil tends to be less than 85 °.

  The other components of the copper sulfate-based copper electrolyte 2 are the same as the other components of the copper sulfate-based copper electrolyte 1, and the meanings of the upper and lower limits of the concentration are also the same. Moreover, the meaning which the upper limit and lower limit regarding the solution temperature to be used and a current density have is the same as the case of the above-described copper sulfate-based copper electrolyte 1.

Form of copper clad laminate according to the present invention: The copper clad laminate according to the present invention is obtained by using the above-mentioned roughened copper foil. The roughened copper foil according to the present invention can be bonded to any insulating resin substrate, and various copper-clad laminates can be produced. The roughened copper foil according to the present invention is a liquid crystal polymer, polyphenylene oxide resin (PPO), polyphenylene ether resin which has been said to be difficult to stably obtain good adhesion even when a conventional copper foil is used. (PPE), cycloolefin polymer (COP), and the like are excellent in adhesion to an insulating resin base material using a resin excellent in high heat resistance and high frequency characteristics. Therefore, the copper clad laminate using the roughened copper foil according to the present invention includes the copper clad laminate laminated with the insulating resin base material using the resin component having excellent high heat resistance and high frequency characteristics as described above. However, the present invention is not limited to this.

  In Example 1, a roughened layer was formed by the method described below on the surface of a 12 μm thick electrolytic copper foil having a 10-point average roughness (Rzjis) value of 1.2 μm, and a zinc-nickel alloy was formed. Rust prevention treatment, chromate treatment, and silane coupling agent treatment were performed to produce a roughened copper foil, and various properties were evaluated.

  In Example 1, using a copper sulfate-based copper electrolyte 1 containing formamidine disulfide, fine copper particles were deposited on the surface of a copper foil to form a roughened surface. The roughening conditions at this time are shown below. In addition, since formamidine disulfide used hydrochloride, the following hydrochloric acid concentrations are concentrations containing chlorine derived from formamidine disulfide. Copper ions were supplied using copper sulfate pentahydrate.

Copper concentration: 30 g / l
Sulfuric acid concentration: 50 g / l
Formamidine disulfide concentration: 0.25 mmol / l
Chlorine concentration: 48mg / l
Solution temperature: 50 ° C
Current density: 50 A / dm ²
Electrolysis time: 27 seconds

  A scanning electron microscope observation image of the roughened layer formed on the copper foil surface as described above is shown in FIG. The fine copper particles at this time have a protruding shape with a top angle of 85 ° or less. This protrusion shape maintains a shape that is almost unchanged even when the following rust prevention treatment and silane coupling agent treatment are performed.

Under the above roughening conditions, fine copper particles were deposited on the surface of the copper foil, and then a rust-proofing layer was provided. The rust-proofing layer contains 2 g / l nickel sulfate, 0.5 g / l zinc pyrophosphate, 80 g / l potassium pyrophosphate, and a nickel-zinc alloy plating solution with a liquid temperature of 40 ° C. and a pH of 10 Electrolysis was performed under conditions of a current density of 1.1 A / dm ² to form a nickel-zinc alloy layer so as to cover the fine copper particles of the roughened layer. Furthermore, a chromate layer was formed by electrolysis in order to strengthen various properties such as a rust prevention function. Hereinafter, when forming a nickel-zinc alloy layer and a chromate layer, the same conditions were adopted.

  Further, a silane coupling treatment layer was formed on the chromate treatment layer. The formation of the silane coupling treatment layer is performed by adsorbing the surface of the chromate layer by spraying with γ-aminopropyltrimethoxysilane added at a concentration of 5 g / l using ion-exchanged water as a solvent. This was carried out by maintaining the foil temperature in a drying furnace in an atmosphere of 180 ° C. for 10 seconds to remove moisture and promote the condensation reaction of the silane coupling agent. Hereinafter, the same conditions were employed when the silane coupling agent treatment was performed.

  As described above, fine copper particles were deposited on the surface of the copper foil to obtain a roughened copper foil having a rust preventive treatment and a silane coupling agent treatment layer. And various evaluation was performed using this roughening process copper foil. The evaluation results are summarized in Table 1.

  The sample for peel strength measurement was prepared by laminating the roughened copper foil and the liquid crystal polymer base material at a press temperature of 290 ° C. to produce a copper clad laminate, and using an etching method to measure the peel strength. What formed the 10 mm width linear circuit was used. And the adhesion strength at the time of peeling this linear circuit toward a 90 degree direction with respect to a liquid crystal polymer base material was measured as peeling strength. The color difference meter and the Zygo interferometer used for the measurement are those described above.

  In Example 2, using the same copper foil as in Example 1, a roughening treatment layer was formed by the method described below, and in the same manner as in Example 1, zinc-nickel alloy rust prevention treatment, chromate treatment, A silane coupling agent treatment was performed to produce a roughened copper foil, and various properties were evaluated. Therefore, since only the formation of the roughening treatment layer is different, only the formation of the roughening treatment layer will be described.

In Example 2, fine copper particles were deposited on the surface of the copper foil using a copper sulfate-based copper electrolyte solution 2 containing thiourea to form a roughened surface. The roughening conditions at this time are shown below. Copper ions were supplied using copper sulfate pentahydrate. Furthermore, preliminary energization of 40 A / dm ² × 8 minutes was performed on the copper sulfate-based copper electrolyte.

Copper concentration: 40 g / l
Sulfuric acid concentration: 50 g / l
Thiourea concentration: 0.5 mmol / l
Chlorine concentration: 60mg / l
Solution temperature: 50 ° C
Current density: 70 A / dm ²
Electrolysis time: 20 seconds

  A scanning electron microscope image of the roughened layer formed on the copper foil surface as described above is shown in FIG. The fine copper particles at this time have a protruding shape with a top angle of 85 ° or less. This protrusion shape maintains a shape that is almost unchanged even when the following rust prevention treatment and silane coupling agent treatment are performed.

  Under the above roughening conditions, fine copper particles are deposited on the surface of the copper foil, a rust prevention layer (nickel-zinc alloy layer, chromate layer) and a silane coupling treatment layer are formed, and the fine copper particles are formed on the copper foil surface. And a roughened copper foil provided with a rust preventive treatment and a silane coupling agent treatment layer was obtained. And various evaluation was performed using this roughening process copper foil. The evaluation results are summarized in Table 1. The evaluation method, measurement method, and the like are the same as in Example 1.

  In this Example 3, when the sample for peeling strength measurement in Example 1 was prepared, the liquid crystal polymer substrate used in Example 1 was replaced with a liquid crystal polymer substrate having a different thermal deformation temperature, and the press temperature was changed. Only the point which was 310 degreeC and the roughening process conditions differ. The roughening treatment conditions are shown below. Therefore, the overlapping description is omitted.

Copper concentration: 30 g / l
Sulfuric acid concentration: 50 g / l
Formamidine disulfide concentration: 0.25 mmol / l
Chlorine concentration: 48mg / l
Solution temperature: 50 ° C
Current density: 60 A / dm ²
Electrolysis time: 23 seconds

  This Example 4 differs only in the sulfuric acid concentration, the current density, and the electrolysis time among the electrolysis conditions used in Example 3 when preparing the peel strength measurement sample in Example 3. The roughening treatment conditions are shown below. Therefore, the overlapping description is omitted.

Copper concentration: 30 g / l
Sulfuric acid concentration: 75g / l
Formamidine disulfide concentration: 0.25 mmol / l
Chlorine concentration: 48mg / l
Solution temperature: 50 ° C
Current density: 45 A / dm ²
Electrolysis time: 12 seconds

  The roughened copper foil according to the present invention has a low profile surface roughened with fine copper particles having an unprecedented shape, and includes a liquid crystal polymer, a polyphenylene oxide resin (PPO), a polyphenylene ether resin (PPE), and a cycloolefin polymer. It has good adhesion to a resin base material that is excellent in high heat resistance and high frequency characteristics such as (COP). Therefore, by using this roughened copper foil, it is possible to produce a high-quality copper-clad laminate, and as a result, it is possible to stably produce a printed wiring board having excellent heat resistance and high frequency characteristics.

2 Fine copper particles a and b Tangent line θ Top angle

Claims (11)

In the roughened copper foil provided with a roughened surface formed by depositing fine copper particles on the surface of the copper foil,
The roughening-treated copper foil characterized in that the roughening-treated surface includes fine copper particles having a protrusion shape with a top angle of 85 ° or less. ^2. The roughened copper foil according to claim 1, wherein the roughened surface has 0.05 / μm ² or more of protrusion-shaped fine copper particles having a top angle of 85 ° or less. The roughened copper foil according to claim 1 or 2, wherein the L ^* a ^* b ^* color system has an L ^* value of 45 to 67 when the roughened surface is measured with a color difference meter. The roughened copper foil according to any one of claims 1 to 3, wherein the a ^* value of the L ^* a ^* b ^* color system is 19 to 35 when the roughened surface is measured with a color difference meter. . The roughened copper foil according to any one of claims 1 to 4, wherein the b ^* value of the L ^* a ^* b ^* color system is 18 to 33 when the roughened surface is measured with a color difference meter. . The value of 10-point average roughness (Rzjis) of a roughening process surface is 0.6 micrometer-4.2 micrometers, The roughening copper foil in any one of Claims 1-5. The value of the specific surface area of a roughening process surface is 1.05-3.40, The roughening process copper foil in any one of Claims 1-6. A roughened copper foil provided with at least one surface treatment layer of a rust prevention treatment layer and a silane coupling agent treatment layer on the surface of the roughening treatment copper foil according to any one of claims 1 to 7. Using a copper sulfate-based copper electrolyte, a method for producing a roughened copper foil comprising a roughened surface on which fine copper particles are deposited on the surface of the copper foil,
As the copper sulfate-based copper electrolyte used for forming the fine copper particles, the copper concentration is 20 g / l to 50 g / l, the sulfuric acid concentration is 25 g / l to 100 g / l, and the formamidine disulfide concentration is 0.1 mmol / l to 0. A method for producing a roughened copper foil, characterized by using a material having a composition of 3 mmol / l and a chlorine concentration of 25 mg / l to 80 mg / l. Using a copper sulfate-based copper electrolyte, a method for producing a roughened copper foil comprising a roughened surface on which fine copper particles are deposited on the surface of the copper foil,
As the copper sulfate-based copper electrolyte used for forming the fine copper particles, the copper concentration is 20 g / l to 50 g / l, the sulfuric acid concentration is 25 g / l to 100 g / l, and the thiourea concentration is 0.2 mmol / l to 0.00. The manufacturing method of the roughening process copper foil characterized by using what has a composition of 6 mmol / l and chlorine concentration 20 mg / l-130 mg / l. A copper-clad laminate obtained by using the roughened copper foil according to any one of claims 1 to 8.