TWI756038B - Roughened copper foil, copper foil with carrier, copper clad laminate and printed wiring board - Google Patents

Abstract

In the processing of copper clad laminates and the manufacture of printed wiring boards, it provides roughened copper foils that can take into account both excellent high-frequency characteristics and high shear strength. This roughened copper foil has a roughened surface on at least one side. The roughened surface is based on ISO25178, and the developed area ratio Sdr of the interface measured under the conditions of the cut-off wavelength of S filter of 0.55 μm and the cut-off wavelength of L filter of 10 μm is 0.50% or more and 7.00% or less. This roughening treatment The copper foil is based on ISO25178, and the peak vertex density Spd measured under the conditions of the cut-off wavelength of S filter of 3.0 μm and the cut-off wavelength of L filter of 10 μm is 2.00×10 ⁴ mm ^-2 or more 3.30×10 ⁴ mm ^-2 the following.

Description

Roughened copper foil, copper foil with carrier, copper clad laminate and printed wiring board

The present invention relates to a roughened copper foil, a copper foil with a carrier, a copper-clad laminate and a printed wiring board.

In recent years, the MSAP (modified semi-additive method) method has been widely used as a manufacturing method of printed wiring boards suitable for miniaturization of circuits. The MSAP method is a method suitable for forming extremely fine circuits, and in order to activate this feature, it is performed using copper foil with a carrier. For example, as shown in FIGS. 1 and 2, an ultra-thin copper foil 10 is pressure-adhered ( Process (a)), after peeling off the carrier (not shown), through laser perforation as required to form through holes 14 (process (b)). Next, after applying electroless copper plating 15 (process (c)), through exposure and development using dry film 16 , masking with a specific pattern (process (d)), and applying electroless copper plating 17 (process (e) ). After removing the dry film 16 and forming the wiring portion 17a (process (f)), the unnecessary ultra-thin copper foil and the like between the adjacent wiring portions 17a and 17b are removed by etching over the entire thickness of these (process (process (process)). g)), the wiring 18 can be formed in a specific pattern. Here, in order to improve the physical adhesion between the circuit and the substrate, the surface of the ultra-thin copper foil 10 is generally roughened.

In fact, several copper foils with a carrier that are excellent in fine circuit formability by the MSAP method or the like have been proposed. For example, in Patent Document 1 (International Publication No. 2016/117587), it is disclosed that the average distance between the surface peaks of the surface having the peeling layer side is 20 μm or less, and that the maximum height difference of the fluctuation between the peeling layer and the surface on the opposite side is 1.0 The copper foil with a carrier of the ultra-thin copper foil of μm or less can achieve both the fine circuit formability and the laser processability according to the relevant form. In addition, in Patent Document 2 (Japanese Patent Laid-Open No. 2018-26590), it is disclosed that the ratio Sp/ Copper foil with carrier with Spk of 3.271 or more and 10.739 or less.

However, with the high-performance of portable electronic devices in recent years, high-speed processing of a large amount of information, and high frequency of signals, there is a demand for printed wiring boards suitable for high-frequency applications. In such a high-frequency printed wiring board, in order to transmit a high-frequency signal without degrading the quality, it is desired to reduce the transmission loss. Although the printed wiring board has copper foil and insulating resin base material processed on the wiring pattern, the transmission loss is mainly caused by the conductor loss caused by the copper foil and the dielectric loss caused by the insulating resin base material.

This part is known to be roughened copper foil for the purpose of reducing transmission loss. For example, Patent Document 3 (Japanese Patent No. 6462961) discloses that on at least one side of the copper foil, a surface-treated copper foil in which a roughening treatment layer, an anti-rust treatment layer and a silane coupling layer are laminated in this order, The developed area ratio Sdr of the interface measured from the surface of the silane coupling layer is 8% or more and 140% or less, the quadratic mean square root surface slope Sdq is 25° or more and 70° or less, and the aspect ratio Str of the surface features is 0.25 or more and 0.79 or less. . When the copper foil is treated according to the relevant surface, it is possible to manufacture a printed wiring board with low transmission loss of high-frequency electrical signals and excellent adhesion during reflow soldering. [Prior Art Literature] [Patent Literature]

[Patent Document 1] International Patent Publication No. 2016/117587 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-26590 [Patent Document 3] Japanese Patent No. 6462961

As described above, from the viewpoint of high-frequency transmission, there is a demand for copper foil with low transmission loss (ie, copper foil with excellent high-frequency characteristics) as a material for forming circuit wiring for transmitting signals. The smoothing of the copper foil and the miniaturization of the roughened particles can suppress the transmission loss, but the physical adhesion between the copper foil and the substrate resin and the like is lowered.

One of the physical adhesion indexes between the circuit and the substrate is the shear strength (Share strength). Shear strength is maintained above a certain level. However, in order to ensure the shear strength above a certain level, the roughening particles of the copper foil have to be increased, and there is a problem that it is difficult to achieve both high-frequency characteristics and circuit adhesion. In this part, as described above, Patent Document 3 discloses a surface-treated copper foil that achieves both high-frequency characteristics and circuit adhesion. However, in order to obtain more excellent high-frequency characteristics, when a smoother copper foil is used , it is also required to ensure circuit tightness.

The inventors of the present invention have found that, for the current roughened copper foil, the developed area ratio Sdr of the interface and the peak vertex density Spd specified in ISO25178 can give a surface profile controlled in a specific range, and the copper clad laminate can be used. The processing and even the manufacture of printed wiring boards can achieve both excellent high frequency characteristics and high shear strength.

Therefore, the object of the present invention is to provide a roughened copper foil that can achieve both excellent high-frequency characteristics and high shear strength in the processing of copper-clad laminates and even in the manufacture of printed wiring boards.

According to one aspect of the present invention, it is provided on at least one side of a roughened copper foil having a roughened surface, wherein the roughened surface is based on ISO25178, with a cutoff wavelength of 0.55 μm in an S filter and an L filter. The developed area ratio Sdr of the interface measured under the condition of the cut-off wavelength of 10μm formed by the filter is 0.50% or more and less than 7.00%. According to ISO25178, under the conditions of the cut-off wavelength of S filter of 3.0μm and the cut-off wavelength of L filter of 10μm The peak density Spd of the measured peak is a roughened copper foil of 2.00×10 ⁴ mm ⁻² or more and 3.30×10 ⁴ mm ⁻² or less.

According to another aspect of the present invention, there is provided a copper with a carrier including a carrier, a peeling layer provided on the carrier, and the roughened copper foil provided on the peeling layer with the roughened surface facing outward. foil.

According to another aspect of this invention, the copper clad laminate provided with the said roughening process copper foil is provided.

According to another aspect of this invention, the printed wiring board provided with the said roughening process copper foil is provided.

definition

Definitions of terms and parameters used to specify the present invention are shown below.

In this specification, the "expanded area ratio Sdr of the interface" is a parameter indicating how much the expanded area (surface area) of the defined area measured in accordance with ISO25178 increases with respect to the area of the defined area. However, in this specification, the developed area ratio Sdr of the interface is expressed as an increase (%) of the surface area. The smaller the value, the closer to the flat surface shape is displayed, and the Sdr of the completely flat surface becomes 0%. On the other hand, the larger this value is, the more uneven surface shape is displayed. For example, when the Sdr of a surface is 40%, the surface shows a 40% increase in surface area from a completely flat surface.

In this specification, "peak apex density Spd" refers to a parameter indicating the number of peak apexes per unit area measured in accordance with ISO25178, and is calculated only as a peak apex larger than 5% of the maximum amplitude of the contour surface. When this value is large, the number of contact points with other objects is displayed.

In this specification, "surface load curve" (hereinafter, simply referred to as "load curve") refers to a curve with a load area ratio of 0% to 100% measured in accordance with ISO25178. The load area ratio is a parameter representing the area of the area above a certain height c, as shown in FIG. 3 . The load area ratio at the height c corresponds to Smr(c) in FIG. 3 . As shown in Fig. 4, the load area ratio is 0% along the load curve, and the difference between the load area ratios is 40%. The broken line of the load curve is drawn. Move from the load area ratio to 0%, and the inclination of the broken line is the most gentle. The position is called the central part of the load curve. For this central portion, a straight line that minimizes the sum of the squares of the deviations in the vertical axis direction is called an equivalent straight line. The part included in the range of the height of the load area ratio of the equivalent straight line from 0% to 100% is called the core part. The part higher than the core part is called the protruding peak part, and the part lower than the core part is called the protruding valley part.

In this specification, the "level difference Sk of the core part" is the value obtained by subtracting the minimum height from the maximum height of the core part measured according to ISO25178. The parameter calculated from the height difference.

In this specification, "maximum height Sz" is a parameter representing the distance from the highest point to the lowest point of the surface measured in accordance with ISO25178.

In the present specification, "aspect ratio Str of surface properties" means a parameter of isotropy or anisotropy of surface properties measured in accordance with ISO25178. Str is in the range of 0 to 1, usually Str>0.5 shows strong isotropy, on the contrary Str<0.3 shows strong anisotropy.

The developed area ratio Sdr of the interface, the peak vertex density Spd, the level difference Sk of the core, the maximum height Sz and the aspect ratio Str of the surface properties are the specific measurement areas of the surface that can be roughened (for example, 16384 μm ² The second dimension area) The surface profiles were measured by a commercially available laser microscope and calculated separately. In this specification, the values of the developed area ratio Sdr of the interface, the step difference Sk of the core, the maximum height Sz, and the aspect ratio Str of the surface features are set at the cutoff wavelength of 0.55 μm for the S filter and the cutoff wavelength for the L filter. The value measured under the condition of 10μm. In addition, in this specification, the numerical value of the peak vertex density Spd coefficient is a value measured under the conditions of a cutoff wavelength of 3 μm formed by an S filter and a cutoff wavelength of 10 μm formed by an L filter.

In this specification, the "electrode surface" of the carrier refers to the surface that is in contact with the cathode when the carrier is fabricated.

In this specification, the "precipitation surface" of the carrier refers to the surface on the side where the electrolytic copper is deposited during the manufacture of the carrier, that is, the surface on the side not in contact with the cathode.

Roughened copper foil The copper foil obtained by the present invention is a roughened copper foil. This roughened copper foil has a roughened surface on at least one side. The surface area ratio Sdr of the roughened interface is 0.50% or more and 7.00% or less, and the peak vertex density Spd is 2.00×10 ⁴ mm ^-2 or more and 3.30×10 ⁴ mm ^-2 or less. In this way, in the roughened copper foil, the developed area ratio Sdr of the interface and the peak density Spd of the peak are given to the surface profile controlled in each specific range, in the processing of the copper clad laminate and the production of the printed wiring board. , can achieve both excellent high frequency characteristics and high shear strength.

Excellent high-frequency characteristics and high shear strength are originally difficult to achieve. As mentioned above, in order to obtain excellent high-frequency characteristics, generally, it is required to make the roughening particles smaller. On the other hand, in order to improve the circuit The shear strength, in general, is required to make the roughened particles larger. Therefore, the shear strength is not simply proportional to the specific surface area and roughening height, etc., which have been conventionally used for evaluation, and it is difficult to control the shear strength. In this regard, the present inventors found that it is effective to evaluate the expansion area ratio Sdr of the combined interface and the peak vertex density Spd in order to obtain the correlation of the physical properties such as high-frequency characteristics and shear strength. Specifically, it is found that the edge controls the interface expansion area ratio Sdr to a very small range, which makes the surface of the roughened copper foil remarkably smooth. By controlling the peak vertex density Spd to a small value, although the high frequency The fine surface with excellent characteristics can also obtain a roughened copper foil with suitable protrusion height and protrusion density and specific surface area to ensure high shear strength. That is, first, when the expansion area ratio Sdr of the interface is controlled within a specific range, when the variation in the size of the roughened particles on the surface of the roughened copper foil is large, the number of extremely small particles that cannot provide shear strength increases. , the peak apex density Spd tends to increase. On the other hand, according to the roughened copper foil of the present invention, the roughened particles with an appropriate size for imparting shear strength are attached to the roughened surface without unevenness, even if the developed area ratio Sdr of the interface is controlled to a very small range When , the vertex density Spd of this peak can also be controlled to a smaller value. In this way, when the copper foil is roughened according to the present invention, excellent high-frequency characteristics and high shear strength (more importantly, high circuit adhesion in terms of shear strength) can be realized.

From the viewpoint that excellent high-frequency characteristics and high shear strength can be achieved in a good balance, the developed area ratio Sdr of the interface of the roughened surface of the roughened copper foil is 0.50% or more and 7.00% or less, preferably 0.50% or more. 4.00% or less, more preferably 0.50% or more and 2.00% or less. Within this range, even if it is a fine surface (roughening height) with excellent high-frequency characteristics, a sufficient adhesion area between the copper clad laminate and the laminated resin can be ensured during the manufacture of printed wiring boards, and the shear strength can be improved. The point of view of circuit tightness.

From the viewpoint that excellent high-frequency characteristics and high shear strength can be achieved in a good balance, the peak density Spd of the roughened surface of the roughened copper foil is 2.00×10 ⁴ mm ^-2 or more and 3.30×10 ⁴ mm ^-2 Below, it is preferably 2.00×10 ⁴ mm ^-2 or more and 2.80×10 ⁴ mm ^-2 or less, more preferably 2.00×10 ⁴ mm ^-2 or more and 2.45×10 ⁴ mm ^-2 or less. Within such a range, sufficient adhesion points between the copper clad laminate and the laminated resin can be ensured during the manufacture of printed wiring boards, and at the same time, the lengthening of the transmission path of high-frequency signals can be suppressed, and the transmission loss can be reduced.

The roughened copper ^foil is preferably 7000 or more, preferably 8000 or more and 15000 or less. More preferably, it is 9000 or more and 12000 or less. For this reason, by controlling the ratio of the developed area ratio Sdr of the interface to the peak vertex density Spd within the above-mentioned ranges, the roughened surface can be made into roughened particles of an appropriate size that impart shear strength to the roughened surface. The structure of the roughened surface makes it easier for the roughened particles constituting the roughened surface to sink into the resin evenly. As a result, excellent high-frequency characteristics can be obtained, and high shear strength can be ensured.

For the roughened copper foil, the maximum height Sz (μm) of the roughened surface and the product of the peak vertex density Spd (mm ^-2 ) are preferably Sz×Spd of 20,000 or more, preferably 24,000 or more and 65,000 or less, more Preferably, it is more than 25,000 and less than 35,000. For the roughened copper foil, while keeping the developed area ratio Sdr within the above-mentioned range, by controlling Sz×Spd in such a range, the smoothness of the roughened copper foil can be ensured in a high balance, and the high density of the roughened surface can be ensured. The state of larger protrusions (roughened particles) improves the adhesion with resin while maintaining excellent high-frequency characteristics. As a result, excellent high-frequency characteristics can be obtained, and high shear strength can be ensured. In addition, from the viewpoint of realizing a fine surface with better high-frequency characteristics, the maximum height Sz of the roughened surface of the roughened copper foil is preferably 1.3 μm or less, preferably 0.1 μm or more and 0.9 μm or less, and more It is preferably 0.4 μm or more and 0.9 μm or less.

The aspect ratio Str of the surface properties of the roughened copper foil is preferably 0.90 or less, preferably 0.30 or more and 0.90 or less, more preferably 0.50 or more and 0.90 or less. Within such a range, even if there are fluctuations in the close contact with the resin on the roughened surface, it is beneficial to the isotropy of the high-frequency characteristics. As a result, high shear strength can be ensured, and excellent high frequency characteristics can be realized.

From the viewpoint that excellent high-frequency characteristics and high shear strength can be achieved in a good balance, the level difference Sk of the core portion of the roughened surface of the roughened copper foil is preferably 0.05 μm or more and 0.30 μm or less, more preferably 0.05 μm or more and 0.20 μm or less, more preferably 0.05 μm or more and 0.15 μm or less. Within such a range, even if it is a fine surface (roughened height) excellent in high-frequency characteristics, the roughened particles constituting the roughened surface are evenly entrapped in the resin, and the adhesiveness with the resin is further improved. That is, when there is unevenness in the roughening treatment, the unevenness becomes a protruding peak portion of the roughening treatment surface. However, such unevenness (protruding peak portion) is an improvement in circuit adhesion from the viewpoint of difficulty in imparting shear strength. In this section, parameters such as the maximum height Sz used in the previous evaluations include the prominent peaks. Therefore, according to such a parameter, when the improvement of the circuit adhesion is achieved, the roughening height tends to be increased, and as a result, the high-frequency characteristic tends to deteriorate. In contrast, the level difference Sk of the core portion is a parameter that does not include the protruding peak portion as described above. Therefore, using the level difference Sk of the core portion as an evaluation index, the adhesiveness with the resin can be improved, and as a result, the increase in the roughening height can be suppressed.

The thickness of the roughened copper foil is not particularly limited, but is preferably 0.1 μm or more and 35 μm or less, preferably 0.5 μm or more and 5.0 μm or less, and more preferably 1.0 μm or more and 3.0 μm or less. However, the roughened copper foil is not limited to the surface of the usual copper foil, and the roughened copper foil may be roughened on the surface of the copper foil with the carrier copper foil. Here, the thickness of the roughened copper foil does not include the height of the roughened particles formed on the surface of the roughened surface (the thickness of the copper foil itself constituting the roughened copper foil). There are cases where the copper foil having the thickness in the above range is called an ultra-thin copper foil.

The roughened copper foil has a roughened surface on at least one side. That is, the roughened copper foil may have a roughened surface on both sides, and may have a roughened surface only on one side. The roughened surface is typically provided with a plurality of roughened particles (protrusions), and each of these pluralities of roughened particles is preferably composed of copper particles. The copper particles may be made of metallic copper or may be made of a copper alloy.

The roughening treatment to form the roughened surface is preferably performed on the copper foil to form roughened particles with copper or a copper alloy. For example, it is carried out according to the plating method of at least two types of plating processes including a sintering plating process in which fine copper particles are deposited and adhered on the copper foil, and a coating plating process in order to prevent the peeling of the fine copper particles. Roughening treatment is better. At this time, the sintering plating process is carried out in a copper sulfate solution containing a copper concentration of 5 g/L or more and 20 g/L or less and a sulfuric acid concentration of 180 g/L or more and 240 g/L or less, and carboxybenzotriazole (CBTA) of 20 ppm or more and 29 ppm or less. , it is better to carry out electrodeposition. In addition, the coating plating process is carried out in a copper sulfate solution containing a copper concentration of 50 g/L or more and 100 g/L or less and a sulfuric acid concentration of 200 g/L or more and 250 g/L or less. dm ² or more and 4A/dm ² or less, preferably electrodeposition. In this regard, in the sintering plating process, the carboxybenzotriazole in the above-mentioned concentration range is added to the electroplating solution to maintain the etchability close to pure copper, and the developed area ratio Sdr can be controlled for the roughened copper foil. In a very small range, the roughened particles of moderate size imparting shear strength can be adhered to the roughened surface without unevenness, and the peak vertex density Spd can also be controlled to a small value. That is, suitable protrusions satisfying the above-mentioned surface parameters can be easily formed on the treated surface. And more. In the sintering plating process and the coating plating process, compared with the conventional method, electrodeposition is performed at a lower current density, and suitable protrusions satisfying the above-mentioned surface parameters can be easily formed on the treated surface.

As desired, the roughening-treated copper foil system can be rust-proof, and a rust-proof layer may be formed. The anti-rust treatment preferably includes a plating treatment using zinc. The plating treatment using zinc may be either a zinc plating treatment or a zinc alloy plating treatment, and the zinc alloy plating treatment is preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be a plating treatment including at least Ni and Zn, and may further include other elements such as Sn, Cr, and Co. The Ni/Zn adhesion ratio of zinc-nickel alloy plating is preferably 1.2 or more and 10 or less, preferably 2 or more and 7 or less, more preferably 2.7 or more and 4 or less. In addition, the antirust treatment may further include chromate treatment, and this chromate treatment is more preferably carried out on the surface of the plating containing zinc after the zinc plating treatment is used. By doing so, the rust resistance can be further improved. A particularly preferred anti-rust treatment is a combination of zinc-nickel alloy plating treatment followed by chromate treatment.

As desired, the surface of the roughened copper foil may be treated with a silane coupling agent, and a silane coupling agent layer may be formed. Thereby, moisture resistance, chemical resistance, adhesiveness of adhesives, etc. can be improved. The silane coupling agent layer is applied by appropriately diluting the silane coupling agent, and is formed by drying. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-epoxypropylbutyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, etc., or 3-amine. propyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-3-(4-(3-aminopropoxy)butoxy) Amino-functional silane coupling agents such as propyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, or 3-hydrothiopropyltrimethoxysilane Hydrogen thio-functional silane coupling agent such as silane or olefin-functional silane coupling agent such as vinyltrimethoxysilane, vinylphenyltrimethoxysilane, etc., or 3-methylpropionyloxypropyltrimethoxysilane Acrylic-functional silane coupling agent such as silane, imidazole-functional silane coupling agent such as imidazole silane, or triazine-functional silane coupling agent such as triazine silane, etc.

For the above reasons, the roughened copper foil is preferably further provided with an antirust treatment layer and/or a silane coupling agent layer on the roughened surface, preferably both of the antirust treatment layer and the silane coupling agent layer. The antirust treatment layer and the silane coupling agent layer may be formed not only on the roughened surface side of the roughened copper foil, but also on the side where the roughened surface is not formed.

With carrier copper foil As described above, the roughened copper foil of the present invention may be provided in a form with a carrier copper foil. That is, according to a preferred aspect of the present invention, there is provided a copper with carrier including a carrier, a peeling layer provided on the carrier, and the above-mentioned roughened copper foil provided on the peeling layer with the roughened surface facing outward. foil. Of course, the copper foil with a carrier can be constituted by a known layer in addition to the use of the roughened copper foil of the present invention.

The carrier system supports the roughened copper foil to improve the handleability. A typical carrier system includes a metal layer. Examples of such a carrier include aluminum foil, copper foil, stainless steel (SUS) foil, a resin film or glass whose surface is coated with a metal such as copper. Preferably it is copper foil. Although the copper foil may be either a rolled copper foil or an electrolytic copper foil, an electrolytic copper foil is preferable. The thickness of the carrier is typically 250 μm or less, preferably 9 μm or more and 200 μm or less.

Preferably, the surface of the carrier on the release layer side is smooth. That is, in the manufacturing process of the copper foil with a carrier, on the surface of the peeling layer side of a carrier, the ultra-thin copper foil (before roughening process is performed) is formed. When the roughened copper foil of the present invention is used in a form with a carrier copper foil, the roughened copper foil is obtained by subjecting such an ultra-thin copper foil to roughening. Therefore, by smoothing the surface of the release layer side of the carrier, the outer surface of the ultra-thin copper foil can also be smoothed, and the smooth surface of the ultra-thin copper foil is roughened, and it is easy to achieve the above-mentioned specific range. The developed area of the interface is worse than the level of Sdr and the core part by the roughened surface of Sk. In order to smooth the surface of the peeling layer of the carrier, for example, the carrier is used on the cathode surface of the electrolytic foil, and it is ground with a specific type of grinding wheel to adjust the surface roughness. That is, the surface profile of the cathode adjusted in this way is transferred to the electrode surface of the carrier. On the electrode surface of the carrier, an ultra-thin copper foil is formed through the peeling layer. On the outer side of the ultra-thin copper foil, it can be easily The smooth surface state of the above-mentioned roughened surface. The preferred type of grinding wheel is #2000 or more and #3000 or less, preferably #2000 or more and #2500 or less. In addition, from the viewpoint of making the ultra-thin copper foil smoother and the developed area of the resulting roughened copper foil more easily controlled than Sdr within the above-mentioned range, the conditions for electrolytically forming a foil carrier are those when the following additives are used. Conditions are better. That is, the concentration of copper is 60 g/L or more and 100 g/L or less, and the sulfuric acid concentration is 50 g/L or more and 150 g/L or less. As additives, the concentration of the sulfonate of the active sulfur compound is 5 mg/L or more and 1 g. /L or less, make the concentration of the 4-stage ammonium salt polymer with a ring structure to be 5 mg/L or more and 500 mg/L or less, and adjust the chlorine concentration to 10 mg/L or more and 100 mg/L or less. Using DSA (dimensionally stable anode), electrolysis is performed at a liquid temperature of 40°C above 60°C, and a current density of 30A/dm ² or more and 100A/dm ² or less, which can preferably obtain an electrolytic copper foil with a smoother surface. Here, examples of sulfonates of active sulfur compounds used as additives include 3-hydrothio-1-propane sulfonate, bis(3-sulfopropyl)diphenyl sulfide, and the like. As an example of the quaternary ammonium salt polymer which has a cyclic structure, a diallyl dimethyl ammonium chloride polymer etc. are mentioned.

The peeling layer weakens the peeling strength of the carrier, guarantees the stability of the strength, and has a functional layer that inhibits the mutual diffusion between the carrier and the copper foil during high-temperature compression molding. The release layer is generally formed on one side of the carrier, but may be formed on both sides. The peeling layer may be any of an organic peeling layer and an inorganic peeling layer. As an example of the organic component used for the organic peeling layer, a nitrogen-containing organic compound, a sulfur-containing organic compound, a carboxylic acid, etc. are mentioned. Examples of the nitrogen-containing organic compound include triazole compounds, imidazole compounds, and the like, and among them, the triazole compound is preferably a part that is easy to stabilize and peel off. Examples of triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N',N'-bis(benzotriazolylmethyl)urea, 1H-1,2 , 4-triazole and 3-amino-1H-1,2,4-triazole, etc. Examples of the sulfur-containing organic compound include thiothiobenzothiazole, thiocyanate, 2-benzimidazole thiol acid, and the like. As an example of a carboxylic acid, a monocarboxylic acid, a dicarboxylic acid, etc. are mentioned. As an example of the inorganic component used for the inorganic peeling layer, Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, a chromate treatment film, etc. are mentioned. However, the formation of the peeling layer may be performed on at least one surface of the carrier by contacting a solution containing the peeling layer component to fix the peeling layer component on the surface of the carrier. When the carrier is brought into contact with the release layer component-containing solution, the contact may be performed by dipping the release layer component-containing solution, spraying the release layer component-containing solution, or flowing the release layer component-containing solution. Otherwise, a method of forming a film of the peeling layer component by vapor deposition, sputtering, or the like can be employed. In addition, fixation of the carrier surface of the peeling layer component may be performed by adsorption or drying of the solution containing the peeling layer component, electrodeposition of the peeling layer component in the solution containing the peeling layer component, or the like. The thickness of the peeling layer is typically 1 nm or more and 1 μm or less, preferably 5 nm or more and 500 nm or less.

As desired, other functional layers may be provided between the release layer and the carrier and/or the roughened copper foil. Examples of such other functional layers include auxiliary metal layers. The auxiliary metal layer is preferably made of nickel and/or cobalt. By forming such an auxiliary metal layer on the surface side of the carrier and/or the surface side of the roughened copper foil, the mutual diffusion between the carrier and the copper foil can be suppressed during hot pressing at high temperature or for a long time, and the carrier can be guaranteed. The stability of peeling strength. The thickness of the auxiliary metal layer is preferably 0.001 μm or more and 3 μm or less.

CCL The roughened copper foil of the present invention is preferably used in the production of copper-clad laminates for printed wiring boards. That is, according to the preferable aspect of this invention, the copper clad laminate provided with the said roughening process copper foil is provided. By using the roughened copper foil of the present invention, both excellent high-frequency characteristics and high shear strength can be achieved in the processing of copper-clad laminates. This copper-clad laminate includes the roughened copper foil of the present invention, and a resin layer provided in close contact with the roughened surface of the roughened copper foil. The roughened copper foil may be provided on one side of the resin layer, or may be provided on both sides. The resin layer contains a resin, preferably an insulating resin. The resin layer is preferably a prepreg and/or a resin sheet. The prepreg system is a general term for composite materials impregnated with synthetic resins on substrates such as synthetic resin sheets, glass sheets, glass woven fabrics, glass non-woven fabrics, and paper. As a preferable example of an insulating resin, an epoxy resin, a cyanate resin, a bismaleic anhydride imide triazine resin (BT resin), a polyphenylene ether resin, a phenol resin, etc. are mentioned. Moreover, as an example of the insulating resin which comprises a resin sheet, insulating resin, such as an epoxy resin, a polyimide resin, a polyester resin, is mentioned. In addition, the resin layer may contain filler particles and the like made of various inorganic particles such as silica and alumina from the viewpoint of improving insulating properties and the like. The thickness of the resin layer is not particularly limited, but is preferably 1 μm or more and 1000 μm or less, preferably 2 μm or more and 400 μm or less, and more preferably 3 μm or more and 200 μm or less. The resin layer may be constituted by plural layers. The resin layer, such as a prepreg and/or a resin sheet, may be coated on the surface of the copper foil via a pre-coated resin layer, and may be provided on the roughened copper foil.

printed wiring board The roughened copper foil of the present invention is preferably used in the production of printed wiring boards. That is, according to the preferable aspect of this invention, the printed wiring board provided with the said roughening process copper foil is provided. By using the roughened copper foil of the present invention, in the manufacture of printed wiring boards, both excellent high-frequency characteristics and high shear strength can be achieved. The printed wiring board obtained in this embodiment is composed of layers including a laminated resin layer and a copper layer. The copper layer is a layer derived from the roughened copper foil of the present invention. In addition, as for the resin layer, the part related to the copper clad laminate is as described above. In any case, the printed wiring board can be constituted by a known layer in addition to the use of the roughened copper foil of the present invention. As a specific example of the printed wiring board, one or both sides of the prepreg can be printed on one side or both sides of the prepreg to form the circuit on one side or both sides of the laminate to which the roughened copper foil of the present invention is adhered and cured. Wiring boards, or multilayer printed wiring boards, etc. Moreover, as another specific example, the roughened copper foil of this invention is formed on a resin film, and the flexible printed wiring board, COF, TAB tape etc. which form a circuit are formed. As a more specific example, the roughened copper foil of the present invention can be cited, forming the resin-coated copper foil (RCC) coated with the above-mentioned resin layer, using the resin layer as an insulating adhesive material, and laminating the above-mentioned resin layer. After printing the substrate, the roughened copper foil is used as all or a part of the wiring layer to form a circuit multilayer wiring board by the modified semi-additive method (MSAP) method or the elimination method, or to remove the roughened copper foil. Multilayer wiring boards where circuits are formed by a partial additive method, laminates with resin copper foils on semiconductor integrated circuits, and direct laminate wafers for circuit formation are alternately repeated. As a specific example of further development, there are antenna elements formed by laminating the above-mentioned resin-coated copper foil on a substrate circuit, and an adhesive layer is laminated on a glass or resin film to form a pattern for panels and displays. Electronic materials or electronic materials for window glass, electromagnetic wave shielding films, etc., which are coated with a conductive adhesive on the roughened copper foil of the present invention. In particular, the printed wiring board provided with the roughened copper foil of the present invention can be used as an automotive antenna, a mobile phone base station antenna, a high-performance server, and a collision prevention used in a high frequency band with a signal frequency of 10 GHz or more. High-frequency substrates used for applications such as radar are appropriately used. In particular, the roughened copper foil of the present invention is suitable for the MSAP method. For example, when the circuit is formed by the MSAP method, the configuration shown in FIG. 1 and FIG. 2 can be adopted. [Example]

The present invention will be described more specifically through the following examples.

Examples 1, 2, 4 and 7 The copper foil with the carrier with the roughened copper foil was produced and evaluated as follows.

(1) Preparation of the carrier Using the copper electrolyte with the composition shown below, the cathode, and the DSA (dimensionally stable anode) as the anode, electrolysis was carried out at a solution temperature of 50°C and a current density of 70A/dm ² , and the thickness of 18 μm was electrolyzed. Electrolytic copper foil is produced as a carrier. At this time, as a cathode, an electrode whose surface was polished with a #2000 grinding wheel to adjust the surface roughness was used. <Composition of copper electrolyte> - Copper concentration: 80g/L - Sulfuric acid concentration: 300g/L - Chlorine concentration: 30mg/L - Glue concentration: 5mg/L

(2) Formation of peeling layer Immerse the electrode surface of the pickled carrier in a CBTA aqueous solution containing carboxybenzotriazole (CBTA) concentration of 1g/L, sulfuric acid concentration of 150g/L and copper concentration of 10g/L at a liquid temperature of 30°C for 30 seconds. The CBTA component is adsorbed on the electrode surface of the carrier. In this way, on the electrode surface of the carrier, the CBTA layer is formed as an organic peeling layer.

(3) Formation of the auxiliary metal layer The carrier that will form the organic peeling layer is immersed in a solution with a nickel concentration of 20 g/L made of nickel ^sulfate . Nickel with a thickness equivalent to 0.001 μm adhered to the organic peeling layer. Thus, on the organic peeling layer, the nickel layer was formed as an auxiliary metal layer.

(4) Formation of ultra-thin copper foil ^The carrier that forms the auxiliary metal layer is immersed in a copper solution with the composition shown below, and electrolyzed at a solution temperature of 50°C and a current density of 5A/ ^dm2 or more and 30A/dm2 or less, and the thickness of 1.5 The ultra-thin copper foil of μm is formed on the auxiliary metal layer. <The composition of the solution> ‐ Copper concentration: 60g/L ‐ Sulfuric acid concentration: 200g/L

(5) Roughening treatment The surface of the ultra-thin copper foil thus formed is roughened to form a roughened copper foil, thereby obtaining a carrier-attached copper foil. This roughening treatment consists of a sintering plating process for depositing and adhering fine copper particles on the ultra-thin copper foil, and a coating plating process for preventing the falling off of the fine copper particles. In the sintering and plating process, the carboxybenzotriazole (CBTA) of the concentration shown in Table 1 was added to an acidic copper sulfate solution containing a copper concentration of 10 g/L and a sulfuric acid concentration of 200 g/L at a liquid temperature of 25 °C. The current density is shown, and roughening treatment is carried out. In the subsequent coating plating process, electrodeposition was performed using an acidic copper sulfate solution containing a copper concentration of 70 g/L and a sulfuric acid concentration of 240 g/L under the smooth plating conditions of the solution temperature of 52° C. and the current density shown in Table 1. At this time, the CBTA concentration and current density of the sintering plating process and the current density of the coating plating process were appropriately changed from those shown in Table 1, and various samples with different characteristics of the roughened surface were cut.

(6) Antirust Treatment The roughened surface of the obtained copper foil with a carrier was subjected to zinc-nickel alloy plating treatment and chromate treatment to obtain an antirust treatment. First, use a solution containing zinc concentration of 1 g/L, nickel concentration of 2 g/L and potassium pyrophosphate concentration of 80 g/L, under the conditions of liquid temperature of 40 °C and current density of 0.5 A/dm ² , between the roughened layer and the carrier. The surface is plated with zinc-nickel alloy. Next, using an aqueous solution containing 1 g/L of chromic acid, under the conditions of pH 12 and current density of 1 A/dm ² , the surface subjected to the zinc-nickel alloy plating treatment was subjected to chromate treatment.

(7) Silane coupling agent treatment An aqueous solution containing a commercially available silane coupling agent was adsorbed on the surface of the roughened copper foil side with the carrier copper foil, and the water was evaporated through an electric heater to perform the silane coupling agent treatment. At this time, the silane coupling agent treatment is not performed on the carrier side.

(8) Evaluation About the copper foil with a carrier obtained in this way, the evaluation of various characteristics was performed as follows.

(8a) Surface property parameters of the roughened surface The roughened surface of the roughened copper foil was measured in accordance with ISO25178 through surface roughness analysis using a laser microscope (manufactured by Olympus Co., Ltd., OLS5000). Specifically, the surface profile of the area of the roughened surface of the roughened copper foil with an area of 16384 μm ² was measured with a 100-fold lens with a numerical aperture (NA) of 0.95 in the above-mentioned laser microscope. The surface profile of the obtained roughened surface was subjected to noise removal and primary linear surface inclination correction, and then, through the analysis of the surface properties, the maximum height Sz, the developed area ratio Sdr of the interface, the aspect ratio Str of the surface properties, and the ratio of the core portion were carried out. Determination of level difference Sk and peak vertex density Spd. At this time, the measurement of Sz, Sdr, Str, and Sk was performed with the cutoff wavelength of the S filter set to 0.55 μm and the cutoff wavelength of the L filter to be 10 μm. On the other hand, for the measurement of Spd, the cutoff wavelength of the S filter was 3 μm, and the cutoff wavelength of the L filter was 10 μm. The results are shown in Table 1.

(8b) Plated circuit adhesion (shear strength) Using the obtained copper foil with a carrier, a laminate for evaluation was produced. That is, on the surface of the insulating resin substrate, through a prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL-830NSF, thickness 0.1mm), a roughened copper foil with a carrier copper foil was laminated, and the pressure was 4.0MPa. , The temperature is 220℃, after 90 minutes of thermocompression bonding, the carrier is peeled off, and the copper clad laminate can be used as a laminate for evaluation. For the laminated body for evaluation, a dry film is attached, and exposure and development are performed. After the layered body masked with the developed dry film was plated with a pattern to deposit a copper layer with a thickness of 14 μm, the dry film was peeled off. The copper portion exposed by the sulfuric acid-hydrogen peroxide-based etchant was etched to prepare a circuit sample for shear strength measurement with a height of 15 μm, a width of 10 μm, and a length of 200 μm (forming the laminate 134 of the circuit 136 shown in FIG. 5 ). The shear strength when the circuit 136 was biased from the side of the circuit sample for shear strength measurement was measured using a bond strength tester (Nordson DAGE, 4000Plus Bondtester). That is, as shown in FIG. 5, the laminated body 134 forming the circuit 136 is placed on the movable platform 132, each platform 132 moves in the direction of the arrow in the figure, and the pre-fixed detector 138 is pressed against the circuit 136. A lateral force is applied to the side surface of the circuit 136 to deflect the circuit 136 in the lateral direction, and the force (gf) at this time is measured by the detector 138 and used as the shear strength. At this time, the test type was a failure test, and the measurement was carried out under the conditions of a test height of 5 μm, a descending speed of 0.050 mm/s, a test speed of 200 μm/s, a tool movement amount of 0.05 mm, and a failure identification point of 10%. The obtained shear strength was evaluated as the following standard evaluation, and when A or B was evaluated, it was judged as pass. The results are shown in Table 1. <Shear Strength Evaluation Criteria> ‐Evaluation A: Shear strength is 12.50gf or more ‐Evaluation B: Shear strength is 11.50gf or more and less than 12.50gf ‐Evaluation C: Shear strength is less than 11.50gf

(8c) High frequency characteristics Using the obtained copper foil with a carrier, a copper clad laminate was produced. That is, a roughened copper foil with a carrier copper foil is laminated on the surface of the base material (30GHz dielectric positive connection Df=0.005), and after thermocompression bonding, the carrier is peeled off to form a copper clad laminate. For this copper-clad laminate, a microstrip line with a circuit length of 300 mm was formed by the same method as the above (8b) (dry film lamination, exposure and development, pattern plating, and etching after dry film peeling), which became the transmission line. Substrate for property measurement. The transmission characteristic S21 was measured using a network analyzer (N5225B, manufactured by Keysight Corporation) for the transmission characteristic measurement substrate at a characteristic impedance of 50Ω±5Ω at a frequency from 10MHz to 50GHz. The obtained loss amount above 26GHz and below 30GHz is averaged and evaluated according to the following criteria. Then, when the high-frequency characteristic evaluation was A or B, it was judged as pass. The results are shown in Table 1. <High-frequency characteristic evaluation criteria> ‐Evaluation A: The amount of loss is 0.320dB/cm or less ‐Evaluation B: The amount of loss is more than 0.320dB/cm and less than 0.350dB/cm ‐ Evaluation C: The amount of loss exceeds 0.350dB/cm

Examples 3 and 5 The production and evaluation of the copper foil with a carrier were carried out in the same manner as in Example 1 except for the following a) to c). The results are shown in Table 1. a) The preparation of the carrier is carried out according to the procedure shown below. b) Instead of the electrode surface of the carrier, on the precipitation surface of the carrier, the peeling layer, the auxiliary metal layer and the ultra-thin copper foil are formed in this order. c) At this time, the CBTA concentration and current density in the sintering plating process and the current density in the covering plating process were changed to the values shown in Table 1, respectively.

(Preparation of carrier) As the copper electrolyte, a sulfuric acid copper sulfate solution with the composition shown below was used, a titanium electrode with a surface roughness Ra of 0.20 μm was used for the cathode, and DSA (dimensionally stable anode) was used for the anode. The solution temperature was 45°C and the current density was 55A/dm ² for electrolysis, and an electrolytic copper foil with a thickness of 12 μm was obtained as a carrier. <The composition of sulfuric acid copper sulfate solution> - Copper concentration: 80g/L - Free sulfuric acid concentration: 140g/L - Bis(3-sulfopropyl)diphenyl sulfide concentration: 30mg/L - Diallyldimethyl methacrylate Ammonium chloride polymer concentration: 50mg/L ‐ Chlorine concentration: 40mg/L

Example 6 (comparison) In place of the sintering plating process and the covering plating process, the preparation and evaluation of the copper foil with a carrier were performed in the same manner as in Example 3, except that the roughening treatment of the ultra-thin copper foil was performed through the black plating process shown below. The results are shown in Table 1.

(Black Plating Process) For the surface of the ultra-thin copper foil, use the copper electrolytic solution for black roughening with the composition shown below, and conduct electrolysis under the conditions of solution temperature 30°C, current density 50A/dm ² , and time 4sec to carry out black roughening change. <Composition of copper electrolytic solution for black roughening> - Copper concentration: 13g/L - Sulfuric acid concentration: 70g/L - Chlorine concentration: 35mg/L - Sodium polyacrylate concentration: 400ppm

10: Very thin copper foil 11: Insulating resin substrate 11a: Base Substrate 11b: Lower circuit 12: Prepreg 13: Coating layer 14: Through hole 15: Electroless copper plating 16: Dry film 17: Electrical copper plating 17a: Wiring part 18: Wiring 132: Movable Platform 134: Laminate 136: Circuit 138: Detector

[Fig. 1] is a flow chart illustrating the process of the MSAP method, showing the first half of the process (process (a) to (d)). [Fig. 2] is a flow chart for explaining the process of the MSAP method, showing the process of the latter half (process (e) to (g)). [Fig. 3] A load curve determined in accordance with ISO25178 and a graph illustrating the load area ratio. Fig. 4 is a diagram illustrating the load area ratio Smr1 of the protruding peak portion and the core portion determined in accordance with ISO25178, the load area ratio Smr2 of the separated protruding valley portion and the core portion, and the level difference Sk of the core portion. [ Fig. 5] Fig. 5 is a schematic diagram illustrating a method of measuring shear strength.

Claims (11)

A roughened copper foil, the roughened copper foil is attached to at least one side and has a roughened surface, and the roughened surface has a cutoff wavelength of 0.55 μm formed by an S filter and a cutoff formed by an L filter according to ISO25178 The developed area ratio Sdr of the interface measured at a wavelength of 10μm is 0.50% or more and 7.00% or less. According to ISO25178, the peak density of the peak measured under the conditions of the cut-off wavelength of S filter of 3.0 μm and the cut-off wavelength of L filter of 10 μm Spd is 2.00×10 ⁴ mm ^-2 or more and 3.30×10 ⁴ mm ^-2 or less. The roughened copper foil according to claim 1, wherein the developed area ratio Sdr of the interface is 0.50% or more and 4.00% or less. The roughened copper foil according to claim 1 or 2, wherein the ratio of the peak density Spd (mm ^-2 ) to the developed area ratio Sdr (%) of the interface, that is, Spd/Sdr is 7000 or more. The roughened copper foil according to claim 1 or 2, wherein the roughened surface has a maximum height Sz measured according to ISO25178 under the conditions of a cutoff wavelength of 0.55 μm formed by an S filter and a cutoff wavelength of 10 μm formed by an L filter (μm) and the product of the peak density Spd (mm ⁻² ), that is, Sz×Spd, is 20,000 or more. The roughened copper foil as set forth in claim 1 or 2, wherein the roughened surface has surface properties measured according to ISO25178 under the conditions of a cutoff wavelength of 0.55 μm formed by an S filter and a cutoff wavelength of 10 μm formed by an L filter. The aspect ratio Str is 0.90 or less. For the roughened copper foil described in claim 1 or 2, Among them, the step difference Sk of the core part measured according to ISO25178 under the conditions of the cutoff wavelength of S filter of 0.55 μm and the cutoff wavelength of L filter of 10 μm is 0.05 μm or more and 0.30 μm or less. The roughened copper foil according to claim 1 or 2, wherein the roughened surface has a maximum height Sz measured according to ISO25178 under the conditions of a cutoff wavelength of 0.55 μm formed by an S filter and a cutoff wavelength of 10 μm formed by an L filter is 1.3 μm or less. The roughened copper foil according to claim 1 or 2, further comprising a rust-preventive treatment layer and/or a silane coupling agent layer on the roughened surface. A copper foil with a carrier, comprising a carrier, a peeling layer provided on the carrier, and the roughening treatment according to any one of Claims 1 to 8 provided on the peeling layer so that the aforementioned roughening treatment faces outward copper foil. A copper-clad laminate characterized by having the roughened copper foil according to any one of claims 1 to 8. A printed wiring board comprising the roughened copper foil according to any one of Claims 1 to 8.

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