TWI719567B - Roughened copper foil, copper foil with carrier, copper clad laminate and printed wiring board - Google Patents

Abstract

The present invention provides a roughened copper foil with excellent etching properties and high shear strength from the processing of copper clad laminates to the manufacture of printed wiring boards. This roughened copper foil is a roughened copper foil with a roughened surface on at least one side. The roughened surface has a maximum height Sz measured according to ISO25178 of 0.65～1.00μm, which is measured according to ISO25178 The spread area ratio Sdr of the interface is 1.50-4.20, and the peak density Spd measured according to ISO25178 is 6.50×10 ⁶ to 8.50×10 ⁶ pieces/mm ² .

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 process) method has been widely adopted as a manufacturing method of printed wiring boards suitable for the miniaturization of circuits. The MSAP method is a method suitable for forming extremely fine circuits. In order to activate its characteristics, it is carried out using copper foil with a carrier. For example, as shown in FIGS. 1 and 2, an ultra-thin copper foil 10 is placed on an insulating resin substrate 11 with a lower circuit 11b on a base substrate 11a, and a prepreg 12 and a primer layer 13 are used to press to make them adhere to each other. (Step (a)), after peeling off the carrier (not shown), if necessary, through holes 14 are formed by laser perforation (step (b)). Next, after performing electroless copper plating 15 (step (c)), by using the exposure and development of the dry film 16 to mask with a specified pattern (step (d)), electrical copper plating 17 is performed (step (e)). After removing the dry film 16 to form the wiring portion 17a (step (f)), the unnecessary ultra-thin copper foil between the wiring portions 17a and 17a adjacent to each other is completely removed by etching through the thickness (step (g) ), the wiring 18 formed with the specified pattern is obtained. Here, the physical adhesion between the circuit and the substrate should be improved. Generally, the surface of the ultra-thin copper foil 10 is roughened.

In fact, there are several proposals for copper foil with a carrier that is excellent in the formation of fine circuits by the MSAP method. For example, Patent Document 1 (International Publication No. 2016/117587) discloses that the average distance between the peaks of the surface on the side with the release layer is 20 μm or less, and the maximum height difference of the expansion of the surface on the opposite side of the release layer is 1.0 μm or less According to this aspect, the copper foil with carrier of the ultra-thin copper foil can have both fine circuit formation properties and laser processability. In addition, Patent Document 2 (Japanese Patent Application Laid-Open No. 2018-26590) discloses the ratio of the maximum mountain height Sp to the projecting mountain height Spk based on the ISO25178 of the side surface of the ultra-thin copper layer for the purpose of improving the formation of fine circuits. Sp/Spk is 3.271～10.739 copper foil with carrier. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2016/117587 [Patent Document 2] JP 2018-26590 A

In recent years, in order to form finer circuits by the above-mentioned MSAP method or the like, there has been a demand for a layer of smoothing of copper foil and miniaturization of roughened particles. However, due to the smoothing of copper foil and the miniaturization of roughened particles, the etching properties of the copper foil related to the miniaturization of the circuit are improved, but the physical adhesion between the copper foil and the substrate resin is reduced. Especially with the progress of circuit thinning, in the mounting step of the printed wiring board, by adding the physical stress (ie shear stress) in the horizontal direction to the circuit, the circuit becomes easy to peel off, resulting in the problem of reduced yield. In the process. At this point, one of the physical adhesion indicators between the circuit and the substrate is the shear strength (Shear strength). In order to effectively avoid the above-mentioned circuit peeling, it is sought to keep the shear strength above a certain level. However, in order to ensure the shear strength above a certain level, it is necessary to enlarge the roughened particles of the copper foil, and it is difficult to achieve both the etching performance.

The inventors of the present inventors are now in the roughening process of copper foil, by giving the maximum height Sz specified by ISO25178, the expansion area ratio of the interface Sdr, and the peak density Spd of the wave crest are respectively controlled in the specified range of the surface profile, in the copper clad layer From the processing of plywood to the manufacture of printed wiring boards, we have obtained the insight of having excellent etching properties and high shear strength.

Accordingly, the object of the present invention is to provide a roughened copper foil that can have both excellent etching properties and high shear strength from the processing of the copper-clad laminate to the manufacture of the printed wiring board.

According to one aspect of the present invention, there is provided a roughened copper foil, which is a roughened copper foil having a roughened surface on at least one side, and is characterized in that the roughened surface is the largest measured in accordance with ISO25178 The height Sz is 0.65 to 1.00 μm, the spread area ratio Sdr of the interface measured according to ISO25178 is 1.50-4.20, and the peak density Spd measured according to ISO25178 is 6.50×10 ⁶ to 8.50×10 ⁶ pieces/mm ² .

According to another aspect of the present invention, there is provided a copper foil with a carrier, which is provided with a carrier, a peeling layer provided on the carrier, and a peeling layer on which the roughened surface is arranged on the outside. The aforementioned roughening process copper foil.

According to yet another aspect of the present invention, there is provided a copper-clad laminate having the aforementioned roughened copper foil.

According to yet another aspect of the present invention, there is provided a printed wiring board provided with the aforementioned roughened copper foil.

definition The definitions of terms to parameters used to specify the present invention are shown below.

In this manual, the so-called "maximum height Sz" is a parameter indicating the distance from the highest point to the lowest point on the surface measured in accordance with ISO25178. The maximum height Sz can be calculated by measuring the surface profile of a designated measurement area (for example ^{, a two-dimensional area of 6812 μm 2} ) on the roughened surface with a commercially available laser microscope.

In this specification, the "expansion area ratio Sdr of the interface" is a parameter indicating how much the expansion area (surface area) of the defined area measured in accordance with ISO25178 increases relative to the area of the defined area. The smaller the value, the closer to the flat surface shape, and the Sdr of the completely flat surface is 0. On the other hand, the larger the value, the more uneven surface shape. For example, when the Sdr of the surface is 0.4, it means that the surface area is increased by 40% from a completely flat surface. The spread area ratio Sdr of the interface can be ^{calculated by measuring the surface profile of a designated measurement area (for example, a two-dimensional area of 6812 μm 2} ) on the roughened surface with a commercially available laser microscope.

In this specification, the so-called "peak density Spd" is a parameter indicating the number of mountain vertices per unit area measured in accordance with ISO25178. When this value is large, the number of contact points with other objects is more disclosed. The peak density Spd can be calculated by measuring the surface profile of a designated measurement area (for example ^{, a two-dimensional area of 6812 μm 2} ) on the roughened surface with a commercially available laser microscope.

In this specification, the "electrode surface" of the carrier refers to the surface on the side in contact with the cathode during the production of the carrier.

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

The roughened copper foil is a roughened copper foil by the copper foil of the present invention. The roughened copper foil has a roughened surface on at least one side. The maximum height Sz of the roughened surface system is 0.65 to 1.00 μm, the expansion area ratio Sdr of the interface is 1.50 to 4.20, and the peak density Spd of the wave peak is 6.50×10 ⁶ to 8.50×10 ⁶ pieces/mm ² . In this way, in the roughened copper foil, the maximum height Sz, the spread area ratio of the interface Sdr, and the peak density Spd of the peak are respectively controlled to the specified range of the surface profile, which is used in the processing of the copper clad laminate to the printed wiring board. Manufacturing makes it possible to have both excellent etching properties and high shear strength.

It is inherently difficult to have both excellent etching properties and high shear strength. As mentioned above, in order to improve the etching properties of copper foil, generally speaking, when seeking to reduce the roughening particles, in order to improve the shear strength of the circuit, generally speaking, it is seeking to increase the roughening particles. On the other hand, according to the present invention, even if it is unexpected, it becomes possible to have both excellent etching properties and high shear strength. That is, the shear strength is simply out of proportion to the specific surface area or roughness height that has been used for evaluation since the past, and it is difficult to control it. In this regard, the inventors found that in order to obtain correlation with physical properties such as etching properties and shear strength, it is effective to evaluate the expansion area ratio of the combined interface Sdr and the peak density Spd in addition to the correlation maximum height Sz. Furthermore, it has been found that by controlling these surface parameters within the above specified ranges, a fine surface with excellent etching properties can be obtained, and it has the advantages of swelling height, swelling density and specific surface area for ensuring high shear strength. Roughened copper foil. In this way, according to the roughened copper foil of the present invention, excellent etching properties and high shear strength can be achieved. Therefore, it becomes possible to have high circuit adhesion from the so-called viewpoints of excellent fine circuit formation and shear strength.

From the viewpoint of achieving excellent etching properties and high shear strength in a well-balanced manner, the maximum height Sz of the roughened surface of the roughened copper foil system is 0.65 to 1.00 μm, preferably 0.65 to 0.90 μm, more preferably 0.65～0.80μm. Moreover, the spread area ratio Sdr of the interface of the roughened copper foil system roughened surface is 1.50-4.20, Preferably it is 1.80-3.50, More preferably, it is 2.00-3.00. Furthermore, the peak density Spd of the wave crest of the roughened copper foil system roughened surface is 6.50×10 ⁶ to 8.50×10 ⁶ pieces/mm ² , preferably 7.65×10 ⁶ to 8.50×10 ⁶ pieces/mm ² , More preferably, it is 7.80×10 ⁶ to 8.30×10 ⁶ pieces/mm ² .

The product of the maximum height Sz of the roughened copper foil on the roughened surface, the spread area ratio of the interface Sdr and the peak density Spd, namely Sz×Sdr×Spd is preferably 7.50×10 ⁶ ～2.70×10 ⁷ (μm･ Pieces/mm ² ), more preferably 9.00×10 ⁶ to 2.60×10 ⁷ (μm･pieces/mm ² ), still more preferably 1.00×10 ⁷ to 2.00×10 ⁷ (μm･pieces/mm ² ). When it is in this range, it becomes easier to achieve both excellent etching properties and high shear strength.

Although the thickness of the roughened copper foil is not particularly limited, it is preferably 0.1 to 35 μm, more preferably 0.5 to 5.0 μm, and still more preferably 1.0 to 3.0 μm. Furthermore, the roughened copper foil is not limited to those that roughen the surface of the usual copper foil, and may be one that roughens the surface of the copper foil of the copper foil with a carrier.

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

The roughening treatment used to form the roughened surface can be better performed by forming roughened particles with copper or copper alloy on the copper foil. For example, it is preferable to perform roughening treatment in accordance with a plating method that includes at least two types of firing steps for depositing and adhering fine copper particles on the copper foil, and a method for preventing such fine copper particles. A plating step that covers the plating step that comes off. In this case, the baking step is to add 30-50ppm (more preferably 35-50ppm) of carboxybenzotriazole (CBTA) to a copper sulfate solution containing a copper concentration of 5-20g/L and a sulfuric acid concentration of 180-240g/L. ), the electrodeposition is preferably carried out at a temperature of 15 to 35°C, at a temperature of 12 to 24 A/dm ² (more preferably, 12 to 18 A/dm ^{2 ).} In addition, the covering plating step is performed in a copper sulfate solution containing a copper concentration of 50-100 g/L and a sulfuric acid concentration of 200-250 g/L at a temperature of 40-60°C and a temperature of 2.3-4A/dm ² (more preferably 2.5 ~3.5A/dm ² ) Electrodeposition is better. Especially in the firing step, by adding carboxybenzotriazole within the above concentration range to the plating solution, while maintaining the etching properties close to pure copper, it becomes easy to form bumps on the processed surface that are beneficial to satisfy the above surface parameters. . Furthermore, in the burn plating step and the cover plating step, by lowering the current density than the conventional method to perform electrodeposition, it becomes easier to form bumps on the processed surface that are beneficial to satisfying the above-mentioned surface parameters.

According to needs, the roughened copper foil may be subjected to anti-rust treatment to form an anti-rust treatment layer. The anti-rust treatment preferably includes a plating treatment using zinc. The plating treatment using zinc may be either zinc plating treatment or zinc alloy plating treatment, and zinc alloy plating treatment is particularly preferably 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 in zinc-nickel alloy plating is preferably 1.2-10, more preferably 2-7, and still more preferably 2.7-4. In addition, the rust prevention treatment preferably further includes a chromate treatment, and this chromate treatment is more preferably performed on the surface of the plating containing zinc after the plating treatment using zinc. By doing so, the rust resistance can be further improved. The best anti-rust treatment is a combination of zinc-nickel alloy plating treatment and subsequent chromate treatment.

According to needs, the roughened copper foil can be treated with a silane coupling agent on the surface to form a silane coupling agent layer. This can improve moisture resistance, chemical resistance, and adhesion to adhesives, etc. The silane coupling agent layer can be formed by appropriately diluting the silane coupling agent, coating and drying it. Examples of silane coupling agents include epoxy functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane, or 3-amino group Propyl trimethoxysilane, N-2 (aminoethyl) 3-aminopropyl trimethoxysilane, N-3-(4-(3-aminopropoxy) butoxy) propyl- Amino functional silane coupling agents such as 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, or mercapto groups such as 3-mercaptopropyltrimethoxysilane Functional silane coupling agent or olefin functional silane coupling agent such as vinyl trimethoxy silane, vinyl phenyl trimethoxy silane, or propylene such as 3-methacryloxy propyl trimethoxy silane Amino-functional silane coupling agent or imidazole-functional silane coupling agent such as imidazole silane, or triazine-functional silane coupling agent such as triazine silane.

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

Copper foil with carrier As described above, the roughened copper foil of the present invention can be provided in the form of a copper foil with a carrier. That is, according to a preferred aspect of the present invention, there is provided a copper foil with a carrier, which is provided with a carrier, a release layer provided on the carrier, and a roughened surface on the release layer arranged on the outside. The above-mentioned roughening treatment copper foil. Furthermore, the copper foil with a carrier can adopt a well-known layer structure in addition to the roughening process copper foil of this invention.

The carrier system supports the roughened copper foil to improve the operability of the support. The carrier usually contains a metal layer. Examples of such a carrier include aluminum foil, copper foil, stainless steel (SUS) foil, resin film coated with a metal such as copper or glass on the surface, and copper foil is preferred. Although the copper foil may be either a rolled copper foil or an electrolytic copper foil, it is preferably an electrolytic copper foil. The thickness of the carrier is generally 250 μm or less, preferably 9 to 200 μm.

The surface of the carrier on the side of the release layer is preferably smooth. That is, in the manufacturing process of the copper foil with a carrier, an ultra-thin copper foil is formed on the surface of the peeling layer side of the carrier (before the roughening treatment). Accordingly, by smoothing the surface of the carrier on the side of the peeling layer, the surface on the outer side of the ultra-thin copper foil can also be smoothed. By roughening the smooth surface of the ultra-thin copper foil, it becomes easy to achieve the above-mentioned specifications. The roughened surface is the maximum height Sz in the range, the expansion area ratio of the interface Sdr, and the peak density Spd of the wave crest. In order to make the surface of the carrier on the side of the release layer smooth, for example, the surface of the cathode used in the electrolysis of the foil carrier can be polished with a polishing wheel with a designated number to adjust the surface roughness. That is, by transferring the adjusted surface profile of the cathode to the electrode surface of the carrier, the peeling layer is formed on the electrode surface of the carrier to form an ultra-thin copper foil, which can be applied to the outside surface of the ultra-thin copper foil. It is easy to realize the smooth surface state of the above-mentioned roughened surface. Preferably, the number of the polishing wheel is #2000～#3000, more preferably #2000～#2500.

The peeling layer has the function of weakening the peeling strength of the carrier, ensuring the stability of the strength, and suppressing the mutual diffusion that can be caused between the carrier and the copper foil during high-temperature stamping and forming. Although the release layer is formed on the side of the carrier, it is common, but it can also be formed on both sides. The peeling layer may be any one of an organic peeling layer and an inorganic peeling layer. Examples of organic components used in the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, carboxylic acids, and the like. Examples of nitrogen-containing organic compounds include triazole compounds, imidazole compounds, and the like. Among them, triazole compounds are preferred in terms of easy and stable releasability. 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 sulfur-containing organic compounds include mercaptobenzothiazole, Thiocyanuric acid, 2-benzimidazole thiol, and the like. As an example of a carboxylic acid, a monocarboxylic acid, a dicarboxylic acid, etc. are mentioned. On the other hand, as examples of the inorganic components used in the inorganic release layer, Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, chromate treated films, and the like can be cited. The formation of the release layer may be performed by bringing a solution containing the release layer component into contact with the surface of at least one side of the carrier to fix the release layer component on the surface of the carrier. When the carrier is brought into contact with the solution containing the peeling layer component, the contact may be performed by dipping the solution containing the peeling layer component, spraying the solution containing the peeling layer component, or flowing down the solution containing the peeling layer component. In addition, a method of forming a peeling layer component by a vapor deposition method such as vapor deposition or sputtering can also be adopted. In addition, the fixing of the release layer component to the surface of the carrier may be performed by adsorption or drying of the solution containing the release layer component, electrodeposition of the release layer component in the solution containing the release layer component, or the like. The thickness of the peeling layer is generally 1 nm to 1 μm, preferably 5 nm to 500 nm.

If necessary, other functional layers can be provided between the peeling layer and the carrier and/or the roughened copper foil. As an example of such other functional layers, an auxiliary metal layer can be cited. 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, it suppresses the mutual interaction between the carrier and the copper foil during high-temperature or long-term hot pressing. Diffusion can guarantee the stability of the peel strength of the carrier. The thickness of the auxiliary metal layer is preferably set to 0.001 to 3 μm.

Copper Clad Laminate 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 a preferred aspect of the present invention, a copper-clad laminate having the above-mentioned roughened copper foil is provided. By using the roughened copper foil of the present invention, it is possible to have both excellent etching properties and high shear strength in the processing of copper clad laminates. This copper clad laminate is provided with the roughened copper foil of the present invention and a resin layer which is closely attached and provided on the roughened surface of the roughened copper foil. The roughened copper foil can be arranged on one side of the resin layer or on both sides. The resin layer contains resin, and is preferably made of insulating resin. The resin layer is preferably a prepreg and/or a resin sheet. The so-called prepreg is a general term for composite materials in which synthetic resin plates, glass plates, glass woven fabrics, glass non-woven fabrics, paper and other substrates are impregnated with synthetic resins. Preferred examples of insulating resins include epoxy resins, cyanate ester resins, bismaleimide triazine resins (BT resins), polyphenylene ether resins, phenol resins, and the like. In addition, examples of insulating resins constituting the resin sheet include insulating resins such as epoxy resins, polyimide resins, and polyester resins. In addition, the resin layer may contain filler particles composed of various inorganic particles such as silica, alumina, etc., from the viewpoint of improving insulation properties and the like. Although the thickness of the resin layer is not particularly limited, it is preferably 1 to 1000 μm, more preferably 2 to 400 μm, and still more preferably 3 to 200 μm. The resin layer may be composed of a plurality of layers. The resin layer of prepreg and/or resin sheet can be set on the roughened copper foil through the primer resin layer pre-coated on the surface of the 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 a preferred aspect of the present invention, a printed wiring board provided with the above-mentioned roughened copper foil is provided. By using the roughened copper foil of the present invention, it is possible to have both excellent etching properties and high shear strength in the manufacture of printed wiring boards. The printed wiring board of this aspect is composed of a laminated resin layer and a copper layer. The copper layer is derived from the roughened copper foil layer of the present invention. In addition, regarding the resin layer, the copper clad laminate system is as described above. In any case, in addition to using the roughened copper foil of the present invention, the printed wiring board can adopt a well-known layer structure. As a specific example of a printed wiring board, one or both sides of the prepreg are subjected to the roughening treatment of the copper foil of the present invention and then hardened to form a single-sided or double-sided printed circuit on the laminated body. Wiring boards, or multilayer printed wiring boards with multiple layers. In addition, as other specific examples, the roughened copper foil of the present invention is formed on a resin film to form a flexible printed wiring board, COF, TAB tape, etc., which form a circuit. As another specific example, the roughened copper foil of the present invention can be used to form a resin-coated copper foil (RCC) coated with the above-mentioned resin layer, and the resin layer is laminated as an insulating adhesive layer on the above-mentioned printed circuit board. , The roughened copper foil is used as all or part of the wiring layer, and the build-up wiring board of the circuit is formed by methods such as modified ･semi･additive (MSAP) method, subtractive method, etc. , Or remove the roughened copper foil, form the build-up wiring board of the circuit by the semi-additive method, alternately laminate the copper foil with the resin on the semiconductor integrated circuit and the direct build-up method on the wafer formed by the circuit ( direct build-up on wafer) and so on. As a more developmental specific example, an antenna element in which a copper foil with the above resin is laminated on a substrate to form a circuit, and an electronic material for a panel display in which a pattern is formed by laminating on a glass or resin film through an adhesive layer Or electronic materials for window glass, electromagnetic wave barriers and films coated with conductive adhesive on the roughened copper foil of the present invention. In particular, the roughened copper foil of the present invention is suitable for the MSAP method. For example, in the case of forming a circuit by the MSAP method, a configuration as shown in FIG. 2 can be adopted. [Example]

The present invention will be further specifically illustrated by the following examples.

Examples 1-8 and 12-14 The copper foil with a carrier having a roughened copper foil was produced and evaluated as follows.

(1) Preparation of the carrier. Use the copper electrolyte with the following composition, the cathode, and the DSA (Dimensional Stability Anode) as the anode, and electrolyze at a solution temperature of 50°C and a current density of 70A/dm ^{2 to} produce a thickness of 18μm The electrolytic copper foil is used as the carrier. At this time, as the cathode, an electrode whose surface was polished with the number shown in Table 1 was used to adjust the surface roughness. <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 The electrode surface of the acid-washed carrier was immersed in a CBTA aqueous solution containing a carboxyl benzotriazole (CBTA) concentration of 1 g/L, a sulfuric acid concentration of 150 g/L, and a copper concentration of 10 g/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, the CBTA layer is formed as an organic release layer on the electrode surface of the carrier.

(3) Formation of the auxiliary metal layer Use nickel sulfate as the carrier to form the organic release layer, and immerse it in a solution containing the prepared nickel concentration of 20g/L under the conditions of a liquid temperature of 45°C, a pH of 3, and a current density of 5A/dm ² . The adhesion amount of nickel corresponding to a thickness of 0.001 μm was adhered to the organic release layer. In this way, a nickel layer is formed as an auxiliary metal layer on the organic peeling layer.

(4) Formation of ultra-thin copper foil The carrier forming the auxiliary metal layer is immersed in a copper solution of the composition shown below, and electrolyzed at a solution temperature of 50°C and a current density of 5-30A/dm ^{2 to} make the thickness of 1.5μm extremely thin The copper foil 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. This roughening treatment is composed of a firing step for depositing and adhering fine copper particles on the ultra-thin copper foil, and a covering plating step for preventing the fine copper particles from falling off. In the firing step, add carboxybenzotriazole (CBTA) with the concentration shown in Table 1 to an acid copper sulfate solution containing a copper concentration of 10g/L and a sulfuric acid concentration of 200g/L at a liquid temperature of 25°C, as shown in Table 1. The current density is roughened. In the subsequent cover plating step, an acid copper sulfate solution containing a copper concentration of 70 g/L and a sulfuric acid concentration of 240 g/L was used to perform electrodeposition under smooth plating conditions at a liquid temperature of 52° C. and a current density as shown in Table 1. At this time, by appropriately changing the CBTA concentration and current density in the burning plating step and the current density in the covering plating step as shown in Table 1, various samples with different characteristics of the roughened surface were produced. .

(6) Anti-rust treatment The roughened surface of the obtained copper foil with carrier is subjected to anti-rust treatment consisting of zinc-nickel alloy plating treatment and chromate treatment. First, use a solution containing zinc concentration of 1g/L, nickel concentration of 2g/L, and potassium pyrophosphate concentration of 80g/L, at a liquid temperature of 40°C and a current density of 0.5A/dm ² The surface is subjected to zinc-nickel alloy plating treatment. Then, using an aqueous solution containing 1 g/L of chromic acid, chromate treatment was performed on the surface of the zinc-nickel alloy plating treatment under the conditions of ^{pH 12 and current density of 1 A/dm 2.}

(7) Silane coupling agent treatment By adsorbing an aqueous solution containing 5 g/L of 3-glycidoxypropyltrimethoxysilane on the surface of the roughened copper foil side of the copper foil with a carrier, the water is evaporated by an electric heater to perform the silane coupling agent deal with. At this time, the silane coupling agent treatment was not performed on the carrier side.

(8) Evaluation For the copper foil with a carrier obtained in this way, various characteristics were evaluated as follows.

(8a) The surface quality parameters of the roughened surface are analyzed by the surface roughness analysis using a laser microscope (manufactured by Keyence Corporation, VK-X200), and the roughened surface of the roughened copper foil is measured as a basis ISO25178 is carried out. Specifically, the surface profile of the roughened copper foil in an area of 6812 μm ² of the roughened surface was measured with the above-mentioned laser microscope at a magnification of 3000 times. The surface profile of the obtained roughened surface is corrected for surface inclination, and then the maximum height Sz, the spread area ratio of the interface Sdr, and the peak density Spd of the crest are measured by analyzing the surface properties. At this time, for the measurement of Sz, the cut-off wavelength by the S filter is set to 5.0 μm, and the cut-off wavelength by the L filter is set to be 0.025 mm. On the other hand, the measurement of Sdr and Spd did not perform the cut-off value by the S filter and the L filter. The results are shown in Table 1.

(8b) Circuit formation (evaluation of etching) Using the obtained copper foil with a carrier, a laminate for evaluation was produced. That is, on the surface of the inner substrate, through a prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL-830NSF, thickness 0.1mm), the roughened copper foil of the carrier-attached copper foil is laminated with a pressure of 4.0 MPa After hot pressing at 220°C for 90 minutes, the carrier was peeled off to obtain a copper-clad laminate as a laminate for evaluation. A plurality of these evaluation laminates were prepared, and for individual evaluation laminates, etching with sulfuric acid-hydrogen peroxide-based etchant was performed at different times, and the etching amount (depth) required to completely disappear the copper on the surface was measured. The measurement is performed by confirming with an optical microscope (500 times). The etching time is controlled by changing the conveying speed of the etching device. In more detail, when the conveying speed of the etching device is 1.0m/min, the etching amount becomes 1.60μm, and the etching amount is increased every 0.1μm, and the conveying speed is gradually slowed down (that is, the etching is gradually increased). Time) to perform etching of the evaluation laminate. In addition, the etching amount calculated from the conveying speed when the remaining copper cannot be detected by the optical microscope is determined as the etching amount required to completely remove the copper. For example, when etching is performed under the condition of a transport speed of 0.5m/min, the remaining copper cannot be detected by an optical microscope, and the required etching amount becomes 3.20μm (that is, [(1.0m/min)/(0.5m/min )]×1.60μm=3.20μm). In other words, it means that the smaller the value, the less etching can be used to remove the copper on the surface. In other words, it means that the smaller the value, the better the etching performance. The etching amount required to completely remove the copper obtained by the above-mentioned measurement was graded using the following criteria, and the evaluations A and B were judged to be pass. The results are shown in Table 1. <Etching Evaluation Criteria> -Evaluation A: The required etching amount is less than 2.7μm -Evaluation B: The required etching amount exceeds 2.7μm and is below 3.0μm -Evaluation C: The amount of etching required exceeds 3.0μm

(8c) Plating circuit adhesion (shear strength) A dry film was attached to the above-mentioned evaluation laminate, followed by exposure and development. After the laminate is covered by the developed dry film, the copper with a thickness of 13.5μm is chromatographed by pattern plating, and then the dry film is peeled off. The exposed copper portion was etched with a sulfuric acid-hydrogen peroxide etching solution to prepare a circuit sample for measuring shear strength with a height of 15 μm, a width of 10 μm, and a length of 150 μm. Using a bonding strength tester (manufactured by Nordson DAGE, 4000Plus Bondtester), the shear strength when the circuit sample for shear strength measurement was pushed down from the lateral direction was measured. That is, as shown in FIG. 3, by placing the laminated body 134 forming the circuit 136 on the movable platform 132, each platform 132 moves in the direction of the arrow in the figure, and the circuit is pressed on the detector 138 fixed in advance. 136. A lateral force is applied to the side of the circuit 136 to push it down, the force (gf) at this time is measured at the detector 138, and the measured value is adopted as the shear strength. At this time, the test type is defined as the destruction test, and the measurement is performed under the conditions of a test height of 10 μm, a lowering speed of 0.050 mm/s, a test speed of 100.0 μm/s, a tool movement amount of 0.05 mm, and a destruction recognition point of 10%. The obtained shear strength was evaluated according to the following criteria, and evaluations A and B were judged to be qualified. The results are shown in Table 1. ＜Shear strength evaluation standard＞ -Evaluation A: The shear strength is above 6.00gf -Evaluation B: The shear strength is 5.00gf or more but less than 6.00gf -Evaluation C: Shear strength is less than 5.00gf

Example 9 (comparison) Except that the preparation of the carrier is carried out in the order shown below, and instead of the burning plating step and the cover plating step, the roughening treatment of the ultra-thin copper foil is carried out by the black plating step shown below, and other examples 1 Proceed in the same way to make and evaluate the copper foil with carrier. The results are shown in Table 1.

(Preparation of the carrier) As the copper electrolyte, a sulfuric acid copper sulfate solution with the composition shown below is used, a titanium electrode with a surface roughness Ra of 0.20 μm is used for the cathode, and DSA (Dimensional Stability Anode) is used for the anode. Electrolysis was performed at a solution temperature of 45°C and a current density of 55A/dm ^{2 to} obtain an electrolytic copper foil with a thickness of 12 μm as a carrier. <Composition of sulfuric acid copper sulfate solution>-Copper concentration: 80g/L-Free sulfuric acid concentration: 140g/L-Bis(3-sulfopropyl) disulfide concentration: 30mg/L-Diallyldimethyl Concentration of ammonium chloride polymer: 50mg/L ‐ Concentration of chlorine: 40mg/L

(Black plating step) For the precipitation surface of the ultra-thin copper foil, use the copper electrolytic solution for black roughening with the composition shown below, and electrolyze it under the conditions of a solution temperature of 30°C, a current density of 50A/dm ² and a time of 4sec. Perform black roughening. <Composition of copper electrolytic solution for black roughening>-Copper concentration: 13g/L-Free sulfuric acid concentration: 70g/L-Chlorine concentration: 35mg/L-Sodium polyacrylate concentration: 400ppm

Example 10 (comparison) Except that the surface of the ultra-thin copper foil was not roughened, it was carried out in the same manner as in Example 1, and the production and evaluation of the copper foil with a carrier were performed. The results are shown in Table 1.

Example 11 (comparison) Except that the firing step and the cover plating step were carried out as follows, the others were carried out in the same manner as in Example 1, and the production and evaluation of the copper foil with a carrier were performed. The results are shown in Table 1.

(Roughening treatment) In the firing step, add 2 ppm of carboxybenzotriazole (CBTA) to an acid copper sulfate solution containing copper concentration of 10g/L and sulfuric acid concentration of 120g/L at a liquid temperature of 25°C, with a current density of 15A/ dm ² is roughened. In the subsequent cover plating step, an acid copper sulfate solution containing a copper concentration of 70 g/L and a sulfuric acid concentration of 120 g/L is used for electrodeposition under smooth plating conditions ^{with a liquid temperature of 40° C. and a current density of 15 A/dm 2.}

10‧‧‧Very thin copper foil 11a‧‧‧Base material 11b‧‧‧Lower layer circuit 11‧‧‧Insulating resin substrate 12‧‧‧Prepreg 13‧‧‧Primer layer 14‧‧‧Through hole 15‧‧‧Chemical copper plating 16‧‧‧Dry film 17‧‧‧Electrical copper plating 17a‧‧‧Wiring part 18‧‧‧Wiring 132‧‧‧Mobile platform 134‧‧‧Laminated body 136‧‧‧Circuit 138‧‧‧Detector

[Figure 1] is a flowchart for explaining the steps of the MSAP method, showing the first half of the steps (steps (a) to (d)). [Figure 2] is a flowchart for explaining the steps of the MSAP method, showing the second half of the steps (steps (e) ~ (g)). [Figure 3] is a schematic diagram for explaining the method of measuring shear strength.

Claims (9)

A roughened copper foil, which is a roughened copper foil with a roughened surface on at least one side, characterized by the maximum height Sz of the roughened surface measured in accordance with ISO25178, the expansion area ratio of the interface Sdr and the wave peak The vertex densities Spd are 0.65~1.00μm, 1.50~4.20, and 6.50×10 ⁶ to 8.50×10 ⁶ /mm ^{2 respectively} . Such as the roughened copper foil of claim 1, wherein the aforementioned maximum height Sz is 0.65~0.90μm. Such as the roughened copper foil of claim 1, wherein the expansion area ratio Sdr of the aforementioned interface is 1.80~3.50. For example, the roughened copper foil of claim 1, wherein the apex density Spd of the aforementioned wave crest is 7.65×10 ⁶ to 8.50×10 ⁶ pieces/mm ² . Such as the roughened copper foil of claim 1, wherein the product of the maximum height Sz, the spread area ratio of the interface Sdr, and the peak density Spd, namely Sz×Sdr×Spd, is 7.50×10 ⁶ to 2.70×10 ⁷ (μm. Pieces/mm ² ). Such as the roughened copper foil of claim 1, which is further provided with an anti-rust treatment layer and/or a silane coupling agent layer on the roughened surface. A copper foil with a carrier, which is provided with a carrier, a peeling layer provided on the carrier, and any one of claims 1 to 6 provided on the peeling layer with the aforementioned roughening treatment surface set on the outside The described roughening treatment copper foil. A copper clad laminate, which is provided with a roughened copper foil as described in any one of claims 1 to 6. A printed wiring board provided with a roughened copper foil as described in any one of claims 1 to 6.

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