WO2019188712A1 - Roughened copper foil, copper foil with carrier, copper-clad multi-layer board, and printed wiring board - Google Patents

Abstract

Provided is a roughened copper foil having low-roughness suitable for forming a thin-wire circuit and capable, when used in an SAP method, of providing a layered body with a surface profile which allows for not only excellent etching properties for electroless copper plating and excellent dry film resolution, but excellent circuit adhesion in terms of shear strength. This roughened copper foil has a roughened surface at least on one side thereof. The roughened surface is provided with multiple roughening particles, the average value of the ratio L²/S of the square of the circumferential length L (µm) of a roughening particle to the area S (µm²) of the roughening particle in a 10 µm-long cross-section of the roughened copper foil is 16 to 30, and the roughened surface has a ten-point average roughness of 0.7 µm to 1.7 µm.

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 SAP (semi-additive process) method has been widely adopted as a method for manufacturing a printed wiring board suitable for circuit miniaturization. The SAP method is a method suitable for forming an extremely fine circuit, and as an example, it is performed using a roughened copper foil with a carrier. For example, as shown in FIGS. 1 and 2, the roughened copper foil 110 is pressed and adhered to an insulating resin substrate 111 having a base substrate 111a and a lower circuit 111b using a prepreg 112 and a primer layer 113. After the carrier (not shown) is peeled off from the roughened copper foil 110, a via hole 114 is formed by laser drilling as necessary (step (b)). Next, the roughened copper foil 110 is removed by etching to expose the primer layer 113 having the roughened surface profile (step (c)). After the electroless copper plating 115 is applied to the roughened surface (step (d)), it is masked with a predetermined pattern by exposure and development using the dry film 116 (step (e)), and the electrolytic copper plating 117 is applied. (Step (f)). After the dry film 116 was removed to form the wiring portion 117a (step (g)), unnecessary electroless copper plating 115 between the adjacent wiring portions 117a and 117a was removed by etching (step (h)). A wiring 118 formed in a predetermined pattern is obtained.

Thus, in the SAP method using the roughened copper foil, the roughened copper foil itself is removed by etching after laser drilling (step (c)). And since the uneven | corrugated shape of the roughening process surface of a roughening process copper foil is transcribe | transferred to the laminated body surface from which the roughening process copper foil was removed, an insulating layer (for example, primer layer 113 or it) is in a subsequent process. In the absence, adhesion between the prepreg 112) and the plating circuit (for example, the wiring 118) can be ensured. However, since the surface profile suitable for improving the adhesion to the plating circuit tends to be rough unevenness in general, the etching property for the electroless copper plating tends to be lowered in the step (h). That is, as the electroless copper plating bites into rough irregularities, more etching is required to eliminate residual copper.

Therefore, a method has been proposed that can achieve good etching properties while ensuring necessary plating circuit adhesion when used in the SAP method by reducing the roughening particles and having a constricted shape. . For example, Patent Document 1 (International Publication No. 2016/158775) discloses a roughened copper foil having a roughened surface on at least one side, the roughened surface being a plurality of substantially spherical shapes made of copper particles. It is disclosed that a projection is provided, and the average height of the substantially spherical projection is 2.60 μm or less.

International Publication No. 2016/158775

In recent years, with the further miniaturization of circuits required for the SAP method, the adhesion strength (absolute value) between the circuit and the substrate has decreased. By the way, as shown in FIGS. 3A and 3B, the circuit 124 formed on the substrate 122 may be covered with the solder resist 126 (FIG. 3A) or not (FIG. 3B). is there. When the circuit 124 is covered with the solder resist 126, since the circuit 124 is protected by the solder resist 126, the risk that the circuit 124 is peeled off from the substrate 122 during the work process is small, that is, the adhesion between the circuit 124 and the substrate 122 is impaired. The risk is small. On the other hand, when the circuit 124 is not covered with the solder resist 126, the circuit 124 is not protected with the solder resist 126. Therefore, when the adhesion strength with the substrate 122 is reduced due to the miniaturization of the circuit 124, the circuit 124 is peeled off during the work process. Risk increases. In this regard, shear strength is one of the physical adhesion indicators between the circuit and the board. To avoid circuit peeling during the work process, the circuit is fine enough only to a line width that can ensure a certain level of shear strength. It is the present situation that cannot be made. Therefore, in order to miniaturize the circuit 124 that is not covered with the solder resist 126, it is desired that sufficient shear strength can be ensured even with a narrow line width in addition to etching property and dry film resolution. However, even if it is possible to ensure good peel strength (peel strength) with the technique disclosed in Patent Document 1, it is difficult to ensure sufficient shear strength that can cope with thinning.

The inventors of the present invention now have a low-roughness roughened copper foil of a level suitable for forming a thin wire circuit having a ten-point average roughness Rz of 1.7 μm or less by controlling the shape of the roughened particles. We obtained the knowledge that excellent circuit adhesion in terms of shear strength can be realized. In other words, it is a low-roughness roughened copper foil suitable for forming thin wire circuits, but when used in the SAP method, it provides not only etching properties for electroless copper plating but also circuit adhesion in terms of shear strength. Also obtained the knowledge that an excellent surface profile can be imparted to the laminate. Moreover, the knowledge that extremely fine dry film resolution was realizable was also acquired in the dry film image development process in SAP method by using the said roughening process copper foil.

Therefore, the object of the present invention is to provide only a low-roughness roughened copper foil suitable for forming a thin wire circuit, but only etching property and dry film resolution for electroless copper plating when used in the SAP method. It is another object of the present invention to provide a roughened copper foil that can give a laminate a surface profile that is excellent in circuit adhesion in terms of shear strength. Moreover, the other object of this invention is to provide the copper foil with a carrier provided with such a roughening process copper foil.

According to one aspect of the present invention, a roughened copper foil having a roughened surface on at least one side, wherein the roughened surface comprises a plurality of roughened particles,
The average value of the ratio L ² / S of the square of the peripheral length L (μm) of the roughened particles to the area S (μm ² ) of the roughened particles in the cross section having a length of 10 μm of the roughened copper foil is 16 There is provided a roughened copper foil which is 30 or less and has a ten-point average roughness Rz of the roughened surface of 0.7 to 1.7 μm.

According to another aspect of the present invention, a carrier, a release layer provided on the carrier, and the roughened copper foil provided on the release layer with the roughened surface facing outside. The provided copper foil with a carrier is provided.

According to another aspect of the present invention, there is provided a copper clad laminate comprising the roughened copper foil or the carrier-attached copper foil.

According to another aspect of the present invention, there is provided a printed wiring board obtained using the roughened copper foil or the carrier-attached copper foil. Or according to another one aspect | mode of this invention, a printed wiring board is manufactured using the said roughening copper foil or the said copper foil with a carrier, The manufacturing method of a printed wiring board characterized by the above-mentioned is provided. .

It is a process flow chart for explaining the SAP method, and is a diagram showing the first half process (process (a) to (d)). It is a process flow chart for explaining the SAP method, and shows the latter half of the process (processes (e) to (h)). It is a schematic cross section which shows the case where the side surface of the longitudinal direction of a circuit is covered with a soldering resist. It is a schematic cross section which shows the case where a circuit is not covered with a soldering resist. It is a schematic cross section which shows the roughening process surface in the roughening copper foil of this invention. It is a schematic cross section for demonstrating the perimeter length L and area S of the roughening particle | grains in the roughening process copper foil of FIG. It is a schematic diagram for demonstrating the measuring method of a shear strength.

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

In this specification, the “roughened particles” are particles 12 having a size exceeding 150 nm in height, which are directly formed on the surface of the base surface 10a of the roughened copper foil 10, as schematically shown in FIG. It includes all shapes such as a substantially spherical shape, a needle shape, a columnar shape, and an elongated shape, but preferably has a form of a “substantially spherical protrusion”. In the present specification, the “substantially spherical protrusion” is a protrusion having a substantially spherical round shape, and is distinguished from an anisotropic shape protrusion or particle such as a needle shape, a columnar shape, and an elongated shape. is there. As shown as roughened particles 12 in FIG. 4, the substantially spherical protrusion is connected to the base surface 10a of the copper foil at the narrow base portion connected to the base surface 10a of the copper foil. However, the portion other than the root portion may be substantially spherical. Therefore, as long as the substantially spherical protrusion has a generally spherical rounded outline, the presence of minute irregularities or deformation is allowed. In addition, although the said protrusion may only be called a spherical protrusion, since it cannot become a perfect sphere as mentioned above, it should be understood as meaning the substantially spherical protrusion mentioned above. Further, the protrusions 12 a formed on the surface of the roughened particles 12 are not directly formed on the base bottom surface 10 a of the roughened copper foil 10, and constitute a part of the roughened particles 12.

In this specification, the “peripheral length L of roughened particles” means the length L _p of the contour line 12p (solid line portion in FIG. 5) of the cross section of the roughened particles 12, as schematically shown in FIG. The total length (L _p + L _s ) of the length L _S of the line segment 12 s (dotted line portion in FIG. 5) connecting the contact points c ₁ and c ₂ between the contour line 12 _p and the base surface 10 a of the roughened copper foil 10. ). Further, the “area R of the roughened particles” means the area (cross-sectional area) of the figure surrounded by the contour line 12p and the line segment 12s in the cross section of the roughened particle 12, as schematically shown in FIG. It is. The peripheral length L and the area S of the roughened particles 12 can be specified by analyzing a cross-sectional image of the roughened copper foil 10 obtained by SEM observation using commercially available software. For example, image analysis software Image-Pro Plus 5.1J (Media Cybernetics, Inc.) can be used, and image analysis can be performed according to various conditions described in the examples of the present specification.

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

In this specification, the “deposition surface” of the carrier refers to the surface on which the metal is electrolytically deposited during carrier production, that is, the surface not in contact with the cathode.

Roughened copper foil The copper foil according to the present invention is a roughened copper foil. This roughened copper foil has a roughened surface on at least one side. As schematically shown in FIG. 4, the roughened surface is provided with a plurality of roughened particles 12. The average value of the ratio L ² / S of the square of the peripheral length L (μm) of the roughened particles 12 to the area S (μm ² ) of the roughened particles 12 in the cross section having a length of 10 μm of the roughened copper foil 10 is 16 It is 30 or less. The ten-point average roughness Rz of the roughened surface is 0.7 μm or more and 1.7 μm or less. By controlling the shape of the roughened particles in this way, it is a roughened copper foil having a low roughness level suitable for forming a thin wire circuit having a ten-point average roughness Rz of 1.7 μm or less, but in terms of shear strength. Excellent circuit adhesion can be realized. In other words, it is a low-roughness roughened copper foil suitable for forming thin wire circuits, but when used in the SAP method, it provides not only etching properties for electroless copper plating but also circuit adhesion in terms of shear strength. In addition, an excellent surface profile can be imparted to the laminate. In addition, by using the roughened copper foil, extremely fine dry film resolution can be realized in the dry film development step in the SAP method.

Plating circuit adhesion and etching properties for electroless copper plating are inherently difficult to achieve at the same time. That is, as described above, since the surface profile suitable for improving the adhesion to the plating circuit tends to be rough unevenness, the etching property of the electroless copper plating is lowered in the step (h) of FIG. It's easy to do. That is, as the electroless copper plating bites into rough irregularities, more etching is required to eliminate residual copper. In this regard, according to the roughened copper foil of Patent Document 1, it is said that excellent plating circuit adhesion can be secured while reducing the etching amount. However, in recent years, with further miniaturization of the circuit required for the SAP method, the adhesion strength (absolute value) between the circuit and the substrate has been reduced. With the method disclosed in Patent Document 1, a good peel strength is obtained. Even if it is possible to ensure, it is difficult to ensure sufficient share strength that can cope with thinning. Therefore, if the circuit is not covered with the solder resist, it can be said that there is a high risk of circuit peeling during the work process. On the other hand, in the present invention, by controlling the shape of the roughened particles 12, the diameter of the roughened particles can be greatly reduced to a level suitable for forming a thin wire circuit having a ten-point average roughness Rz of 1.7 μm or less. However, it is possible to greatly improve circuit adhesion in terms of shear strength. That is, although the circuit adhesion can be originally reduced by reducing the diameter of the roughened particles 12 represented by Rz within the above range, the ratio L ² / indicating the parameter of the cross-sectional shape of the roughened particles 12 in the present invention. By setting the average value of S to 16 or more and 30 or less, excellent circuit adhesion in terms of shear strength can be realized. And it is thought that very fine dry film resolution can be realized in the dry film development process in the SAP method by satisfying both such excellent adhesion and excellent etching property for electroless copper plating. . Therefore, it is preferable that the roughened copper foil 10 of this invention is used for preparation of the printed wiring board by a semi-additive method (SAP). In other words, it can be said that the roughened copper foil 10 of the present invention is preferably used for transferring the concavo-convex shape to the insulating resin layer for the printed wiring board.

The roughened copper foil 10 of the present invention has a roughened surface on at least one side. That is, the roughened copper foil may have a roughened surface on both sides, or may have a roughened surface only on one side. When both sides have roughened surfaces, the surface on the laser irradiation side (the surface away from the surface that is in close contact with the insulating resin) is also roughened when used in the SAP method. As a result, the laser perforation property can be improved.

The roughened surface is provided with a plurality of roughened particles 12, and each of the plurality of roughened particles 12 is preferably made of copper particles. The copper particles may be made of metallic copper, or may be made of a copper alloy. However, when the copper particles are a copper alloy, the solubility in the copper etching solution may decrease, or the life of the etching solution may decrease due to the alloy components mixed in the copper etching solution. Preferably it consists of.

The average value of the ratio L ² / S of the square of the peripheral length L (μm) of the roughened particles 12 to the area S (μm ² ) of the roughened particles 12 in the cross section having a length of 10 μm of the roughened copper foil 10 is 16 30 or more, preferably 19 or more and 27 or less, more preferably 19 or more and 26 or less, further preferably 19 or more and 25 or less, and particularly preferably 20 or more and 24 or less. Within these ranges, the shear strength can be further improved while effectively preventing the roughened particles 12 from falling off.

The ten-point average roughness Rz of the roughened surface is 0.7 μm or more and 1.7 μm or less, preferably 0.7 μm or more and 1.6 μm or less, more preferably 0.8 μm or more and 1.5 μm or less. Within these ranges, the fine line formability can be further improved while ensuring the desired shear strength. Rz is determined in accordance with JIS B 0601-1994.

It is preferable that the number of the roughened particles 12 in the cross section having a length of 10 μm of the roughened copper foil 10 is 20 or more and 70 or less, more preferably 20 or more and 60 or less, and still more preferably 20 or more and 40. It is as follows. Within these ranges, the shear strength can be further improved while effectively preventing the roughened particles 12 from falling off.

The thickness of the roughened copper foil 10 of the present invention is not particularly limited, but is preferably 0.1 μm to 18 μm, more preferably 0.5 μm to 7 μm, still more preferably 0.5 μm to 5 μm, and particularly preferably It is 0.5 μm or more and 3 μm or less. This thickness includes the roughened particles 12. The roughened copper foil 10 of the present invention is not limited to the surface of the normal copper foil subjected to the roughening treatment, and the surface of the copper foil of the carrier-added copper foil is subjected to the roughening treatment. Also good.

Method for Producing Roughened Copper Foil An example of a preferred method for producing a roughened copper foil according to the present invention will be described. However, the roughened copper foil according to the present invention is not limited to the method described below, and the roughened copper foil according to the present invention is used. It may be manufactured by any method as long as the surface profile of the treated copper foil can be realized.

(1) Preparation of copper foil As copper foil used for manufacture of roughening processing copper foil, use of both electrolytic copper foil and rolled copper foil is possible. The thickness of the copper foil is not particularly limited, but is preferably 0.1 μm to 18 μm, more preferably 0.5 μm to 7 μm, still more preferably 0.5 μm to 5 μm, and particularly preferably 0.5 μm to 3 μm. is there. When the copper foil is prepared in the form of a copper foil with a carrier, the copper foil is prepared by a wet film formation method such as an electroless copper plating method and an electrolytic copper plating method, a dry film formation method such as sputtering and chemical vapor deposition, or It may be formed by a combination thereof.

(2) Roughening treatment At least one surface of the copper foil is roughened using copper particles. This roughening is performed by electrolysis using a copper electrolytic solution for roughening treatment. This electrolysis is preferably performed through a three-step plating process. In the first plating step, the copper concentration is 5 g / L to 20 g / L, the sulfuric acid concentration is 30 g / L to 200 g / L, the chlorine concentration is 20 ppm to 100 ppm, and the 9-phenylacridine (9PA) concentration is 20 ppm to 100 ppm. It is preferable to perform electrodeposition using a copper sulfate solution containing a solution at a temperature of 20 to 40 ° C., a current density of 5 A / dm ^{2 to} 25 A / dm ² and a time of 2 seconds to 10 seconds. In the second plating step, a copper sulfate solution containing a copper concentration of 65 g / L or more and 80 g / L or less and a sulfuric acid concentration of 200 g / L or more and 280 g / L or less is used. Electrodeposition is preferably performed under plating conditions of a density of 1 A / dm ^{2 to} 10 A / dm ² and a time of 2 seconds to 25 seconds. In the third plating step, a copper sulfate solution containing a copper concentration of 10 g / L to 20 g / L, a sulfuric acid concentration of 30 g / L to 130 g / L, a chlorine concentration of 20 ppm to 100 ppm, and a 9PA concentration of 100 ppm to 200 ppm. It is preferable to perform electrodeposition under plating conditions of a liquid temperature of 20 ° C. or more and 40 ° C. or less, a current density of 10 A / dm ² or more and 40 A / dm ² or less, and a time of 0.3 seconds or more and 1.0 seconds or less. By performing the third stage plating process using an additive such as 9PA, minute protrusions are formed on the surface of the roughened particles formed in the first and second stage plating processes, and the ratio L ² / S can be increased. In particular, it is preferable carried out using 1-stage plating process is an additive such as 9pa, total quantity of electricity Q ₂ in the quantity of electricity Q ₁ and second-stage plating process in the first stage of the plating process electrical It is preferable to set the amount (Q ₁ + Q ₂ ) to be 100 C / dm ² or less. In addition, the linear flow rate of the plating solution with respect to the copper foil in the first to third stages of plating is preferably 0.10 m / s or more and 0.50 m / s or less, more preferably 0.15 m / s or more and 0. .45 m / s or less. In this way, a surface profile with a relatively low roughness satisfying the ten-point average roughness Rz ≦ 1.7 μm is formed, and the third stage plating is spread over the entire surface of the roughened particles, and the ratio L ² / Roughened particles with large S are formed.

(3) Rust prevention treatment Since the rust prevention treatment does not affect the shape, peripheral length and area of the roughened particles, and the ten-point average roughness Rz of the roughened surface, the copper foil after the roughening treatment, if desired. May be subjected to a rust-proofing treatment. The rust prevention 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 particularly preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be a plating treatment containing at least Ni and Zn, and may further contain other elements such as Sn, Cr, and Co. The Ni / Zn adhesion ratio in the zinc-nickel alloy plating is preferably 1.2 or more and 10 or less, more preferably 2 or more and 7 or less, and still more preferably 2.7 or more and 4 or less in terms of mass ratio. 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 carrying out like this, rust prevention property can further be improved. A particularly preferable antirust treatment is a combination of a zinc-nickel alloy plating treatment and a subsequent chromate treatment.

(4) Silane coupling agent treatment If desired, the copper foil may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, moisture resistance, chemical resistance, adhesiveness with an adhesive agent, etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying a silane coupling agent and drying. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane, or 3-aminopropyltriethoxysilane, N-2 (amino Amino functions such as ethyl) 3-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane Silane coupling agents, or mercapto-functional silane coupling agents such as 3-mercaptopropyltrimethoxysilane, or olefin-functional silane coupling agents such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane, or 3-methacryloxypropyl Trime Acrylic-functional silane coupling agent such as Kishishiran, and imidazole functional silane coupling agent such as imidazole silane, or triazine functional silane coupling agents such as triazine silane.

Copper foil with carrier The roughened copper foil of the present invention can be provided in the form of a copper foil with carrier. In this case, the carrier-attached copper foil includes a carrier, a release layer provided on the carrier, and the roughened copper foil of the present invention provided on the release layer with the roughened surface facing outside. It becomes. However, a known layer structure can be adopted as the carrier-attached copper foil except that the roughened copper foil of the present invention is used.

The carrier is a layer (typically a foil) for supporting the roughened copper foil and improving its handleability. Examples of the carrier include an aluminum foil, a copper foil, a resin film whose surface is metal-coated with copper or the like, a glass plate, and the like, preferably a copper foil. The copper foil may be a rolled copper foil or an electrolytic copper foil. The thickness of the carrier is typically 200 μm or less, preferably 12 μm or more and 35 μm or less.

The surface on the peeling layer side of the carrier preferably has a 10-point surface roughness Rz of 0.5 μm or more and 1.5 μm or less, more preferably 0.6 μm or more and 1.0 μm or less. Rz can be determined according to JIS B 0601-1994. By giving such a ten-point surface roughness Rz to the surface of the carrier on the release layer side, a desired surface profile is given to the roughened copper foil of the present invention produced thereon via the release layer. Can be easier.

The release layer is a layer having a function of weakening the peeling strength of the carrier, ensuring the stability of the strength, and further suppressing the interdiffusion that may occur between the carrier and the copper foil during press molding at a high temperature. . The release layer is generally formed on one side of the carrier, but may be formed on both sides. The release layer may be either an organic release layer or an inorganic release 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 these, triazole compounds are preferred in terms of easy release stability. Examples of triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N ′, N′-bis (benzotriazolylmethyl) urea, 1H-1,2,4-triazole and 3-amino- And 1H-1,2,4-triazole. Examples of the sulfur-containing organic compound include mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazolethiol and the like. Examples of the carboxylic acid include monocarboxylic acid and dicarboxylic acid. On the other hand, examples of inorganic components used in the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and a chromate-treated film. The release layer may be formed by bringing a release layer component-containing solution into contact with at least one surface of the carrier and fixing the release layer component to the surface of the carrier. The carrier may be brought into contact with the release layer component-containing solution by immersion in the release layer component-containing solution, spraying of the release layer component-containing solution, flowing down of the release layer component-containing solution, or the like. The release layer component may be fixed to the carrier surface by adsorption or drying of the release layer component-containing solution, electrodeposition of the release layer component in the release layer component-containing solution, or the like. The thickness of the release layer is typically 1 nm or more and 1 μm or less, preferably 5 nm or more and 500 nm or less.

The roughened copper foil of the present invention described above is used as the roughened copper foil. The roughening treatment of the present invention is performed by roughening using copper particles. As a procedure, first, a copper layer is formed as a copper foil on the surface of the release layer, and then at least roughening is performed. . Details of the roughening are as described above. In addition, it is preferable that copper foil is comprised with the form of an ultra-thin copper foil in order to utilize the advantage as copper foil with a carrier. The preferable thickness of the ultrathin copper foil is 0.1 μm or more and 7 μm or less, more preferably 0.5 μm or more and 5 μm or less, and further preferably 0.5 μm or more and 3 μm or less.

Other functional layers may be provided between the release layer and the carrier and / or copper foil. An example of such another functional layer is an auxiliary metal layer. The auxiliary metal layer is preferably made of nickel and / or cobalt. By forming such an auxiliary metal layer on the release layer side of the carrier and / or the release layer side of the roughened copper foil, between the carrier and the roughened copper foil during high-temperature or long-time hot press molding. Possible interdiffusion can be suppressed and stability of the peeling strength of the carrier can be ensured. The thickness of the auxiliary metal layer is preferably 0.001 μm or more and 3 μm or less.

Copper- clad laminate The roughened copper foil or carrier-attached copper foil of the present invention is preferably used for the production of a copper-clad laminate for printed wiring boards. That is, according to the preferable aspect of this invention, the copper clad laminated board provided with the said roughening process copper foil or the said copper foil with a carrier is provided. By using the roughened copper foil or the copper foil with carrier of the present invention, a copper clad laminate particularly suitable for the SAP method can be provided. This copper-clad laminate comprises 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, or the copper with carrier of the present invention The foil and a resin layer provided in close contact with the roughened surface of the roughened copper foil in the copper foil with carrier are provided. The roughened copper foil or the copper foil with carrier may be provided on one side of the resin layer or may be provided on both sides. The resin layer comprises a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. The prepreg is a general term for composite materials in which a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass nonwoven fabric, and paper is impregnated with a synthetic resin. Preferable examples of the insulating resin include an epoxy resin, a cyanate resin, a bismaleimide triazine resin (BT resin), a polyphenylene ether resin, and a phenol resin. Examples of the insulating resin that constitutes the resin sheet include insulating resins such as epoxy resins, polyimide resins, and polyester resins. Moreover, the filler particle etc. which consist of various inorganic particles, such as a silica and an alumina, may contain in the resin layer from a viewpoint of improving insulation. The thickness of the resin layer is not particularly limited, but is preferably 1 μm or more and 1000 μm or less, more preferably 2 μm or more and 400 μm or less, and further preferably 3 μm or more and 200 μm or less. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided on a roughened copper foil or a copper foil with a carrier in advance through a primer resin layer applied to the roughened surface of the roughened copper foil.

Printed wiring board The roughened copper foil or carrier-attached copper foil of the present invention is preferably used for the production of a printed wiring board, particularly preferably for the production of a printed wiring board by a semi-additive method (SAP). That is, according to the preferable aspect of this invention, the printed wiring board obtained using the roughening process copper foil mentioned above or the said copper foil with a carrier is provided. By using the roughened copper foil or carrier-attached copper foil of the present invention, in the production of printed wiring boards, sufficient shear strength can be secured to effectively prevent circuit peeling during the work process, and electroless copper A surface profile excellent in etching property for plating can be imparted to the laminate. In addition, by using the roughened copper foil, extremely fine dry film resolution can be realized in the dry film development step in the SAP method. Therefore, it is possible to provide a printed wiring board on which an extremely fine circuit is formed. The printed wiring board according to this aspect includes a layer configuration in which a resin layer and a copper layer are laminated. In the case of the SAP method, the roughened copper foil of the present invention is removed in the step (c) of FIG. 1, and therefore the printed wiring board produced by the SAP method no longer contains the roughened copper foil of the present invention. Only the surface profile transferred from the roughened surface of the roughened copper foil remains. The resin layer is as described above for the copper-clad laminate. In any case, a known layer structure can be adopted for the printed wiring board. Specific examples of the printed wiring board include a single-sided or double-sided printed wiring board in which a circuit is formed on a single-sided or double-sided prepreg and a laminated body obtained by bonding and curing the roughened copper foil of the present invention or a copper foil with a carrier, A multilayer printed wiring board obtained by multilayering these may be used. Other specific examples include a flexible printed wiring board, a COF, a TAB tape and the like that form a circuit by forming the roughened copper foil or the carrier-attached copper foil of the present invention on a resin film. As yet another specific example, a copper foil with resin (RCC) obtained by applying the above resin layer to the roughened copper foil or copper foil with carrier of the present invention is formed, and the resin layer is used as an insulating adhesive layer as described above. After being laminated on the printed circuit board, a roughened copper foil is used as a whole or part of the wiring layer, and a build-up wiring board in which a circuit is formed by a modified semi-additive (MSAP) method, a subtractive method, etc., or a roughening treatment Build-up wiring board with a semi-additive (SAP) circuit formed by removing copper foil, direct build-up-on-wafer, etc. that alternately repeats the lamination of resin-coated copper foil and circuit formation on a semiconductor integrated circuit Can be mentioned. As a more specific example, antenna elements formed by laminating the above resin-coated copper foil on a substrate to form a circuit, panels and electronic materials for panels and displays formed on a glass or resin film via an adhesive layer, and windows Examples thereof include an electronic material for glass, and an electromagnetic wave shielding film obtained by applying a conductive adhesive to the roughened copper foil of the present invention. In particular, the roughened copper foil or the copper foil with carrier of the present invention is suitable for the SAP method. For example, when a circuit is formed by the SAP method, a configuration as shown in FIGS. 1 and 2 can be employed.

The present invention will be described more specifically with reference to the following examples.

Examples 1-3
Preparation and evaluation of the copper foil with a carrier were performed as follows.

(1) Production of Carrier A titanium electrode whose surface was polished with a # 2000 buff was prepared as a cathode. Moreover, DSA (dimensional stability anode) was prepared as an anode. Using these electrodes, the sample was immersed in a copper sulfate solution having a copper concentration of 80 g / L and a sulfuric acid concentration of 260 g / L, and electrolysis was performed at a solution temperature of 45 ° C. and a current density of 55 A / dm ^2. Got as.

(2) Formation of Release Layer The electrode surface side of the pickled carrier is placed in a CBTA aqueous solution having a CBTA (carboxybenzotriazole) 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. So as to adsorb the CBTA component on the electrode surface of the carrier. Thus, a CBTA layer was formed as an organic release layer on the surface of the carrier electrode surface.

(3) Formation of auxiliary metal layer The carrier on which the organic peeling layer is formed is immersed in a solution having a nickel concentration of 20 g / L prepared using nickel sulfate, and the liquid temperature is 45 ° C., the pH is 3, and the current density is 5 A / dm. ^Under the condition ² , nickel having a thickness equivalent to 0.001 μm was deposited on the organic release layer. Thus, a nickel layer was formed as an auxiliary metal layer on the organic release layer.

(4) Ultra-thin copper foil formation The carrier on which the auxiliary metal layer is formed is immersed in a copper sulfate solution having a copper concentration of 60 g / L and a sulfuric acid concentration of 200 g / L, and the solution temperature is 50 ° C. and the current density is 5 A / dm ² or more. Electrolysis was performed at 30 A / dm ² or less, and an ultrathin copper foil having a thickness of 1.2 μm was formed on the auxiliary metal layer.

(5) Roughening process The roughening process was performed with respect to the precipitation surface of the above-mentioned ultra-thin copper foil. This roughening treatment was performed by the following three-stage plating. In the plating process at each stage, a copper sulfate solution having the copper concentration, sulfuric acid concentration, chlorine concentration and 9-phenylacridine (9PA) concentration shown in Table 1 was used, and the current density shown in Table 2 was obtained at the liquid temperature shown in Table 1. I electrodeposited. The energization time in the first stage and second stage plating was 4.4 seconds per time, and the energization time in the third stage plating was 0.6 seconds. Further, the linear flow rate of the plating solution with respect to the ultrathin copper foil was set to 0.25 m / s or more and 0.35 m / s or less. Thus, three types of roughened copper foils of Examples 1 to 3 were produced.

(6) Rust prevention treatment The surface of the roughening treatment layer of the obtained copper foil with a carrier was subjected to a rust prevention treatment comprising zinc-nickel alloy plating treatment and chromate treatment. First, a roughening treatment layer using an electrolytic solution having a zinc concentration of 0.2 g / L, a nickel concentration of 2 g / L, and a potassium pyrophosphate concentration of 300 g / L under the conditions of a liquid temperature of 40 ° C. and a current density of 0.5 A / dm ^2. And the surface of the carrier was subjected to a zinc-nickel alloy plating treatment. Next, a chromate treatment was performed on the surface on which the zinc-nickel alloy plating treatment was performed using a 1 g / L aqueous solution of chromic acid under the conditions of pH 11, liquid temperature 25 ° C., and current density 1 A / dm ² .

(7) Silane coupling agent treatment A silane coupling agent is prepared by adsorbing an aqueous solution containing 3 g / L of 3-aminopropyltrimethoxysilane on the surface of the copper foil with a carrier and evaporating water with an electric heater. Processed. At this time, the silane coupling agent treatment was not performed on the carrier side.

(8) Evaluation of roughened copper foil surface About the obtained roughened copper foil, various characteristics of the surface profile were evaluated as follows.

(8-1) Observation of Roughened Particles A cross-sectional image of the obtained roughened copper foil was obtained, and the average value of the ratio L ² / S and the number of roughened particles per 10 μm of the roughened copper foil were determined as follows: I asked as follows.

(8-1-1) Acquisition of cross-sectional image Using an FIB-SEM apparatus (SII NanoTechnology Co., Ltd., SMI3200SE), the surface of the roughened copper foil was subjected to FIB (Focused Ion Beam) processing to obtain copper. A cross section parallel to the thickness direction of the foil was prepared, and this cross section was observed by SEM (magnification: 36000 times) from a direction of 60 ° with respect to the roughened surface, thereby obtaining a cross section image.

(8-1-2) Calculation of ratio L ² / S A cross-sectional image corresponding to a length of 10 μm of the roughened copper foil was taken into image analysis software Image-Pro Plus 5.1J (manufactured by Media Cybernetics, Inc.). The roughening particles in the cross section were extracted one by one by the function “free curve AO” of the analysis software. After extracting all the roughened particles contained in the cross-sectional image, the contrast was adjusted so that the inside of the roughened particles was white. Next, using the function “count / size” of the analysis software, the roughened particles changed to light colors are automatically recognized, and then the peripheral length L and the area S of each roughened particle are measured by the measurement function. The ratio L ² / S was calculated. The above operation was performed for three different visual fields for each example, and the average value of the ratio L ² / S of all observed coarse particles was adopted as the average value of the ratio L ² / S of the sample.

(8-1-3) Number of Roughened Particles The number of roughened particles in the field of view and the horizontal width of the field of view were measured from the cross-sectional image, and converted to the number per 10 μm length. Measurement was performed for three different fields of view for each example, and the average value was adopted as the number of coarse particles per 10 μm length in the sample.

(8-2) Measurement of 10-point average roughness Rz A roughened surface was observed using a laser microscope (manufactured by Keyence Corporation, VK-9510) equipped with a 150 × objective lens, and a visual field of 6550.11 μm ² The image was acquired. Ten 10 μm × 10 μm regions were arbitrarily selected from the obtained visual field images so as not to overlap each other, and 10-point average roughness Rz was measured according to JIS B 0601-1994. The average value of 10 Rz was adopted as the Rz of the sample.

(9) Production of copper-clad laminate A copper-clad laminate was produced using a copper foil with a carrier. First, a roughened copper foil with carrier is laminated on the surface of the inner layer substrate via a prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL-830NSF, thickness 0.1 mm), pressure 4.0 MPa, temperature After thermocompression bonding at 220 ° C. for 90 minutes, the carrier was peeled off to produce a copper clad laminate.

(10) Fabrication of SAP Evaluation Laminate Next, all the copper foil on the surface was removed with a sulfuric acid-hydrogen peroxide etching solution, followed by degreasing, Pd catalyst application, and activation treatment. The surface thus activated was subjected to electroless copper plating (thickness: 1 μm) to obtain a laminate (hereinafter referred to as “SAP evaluation laminate”) immediately before the dry film was laminated by the SAP method. These steps were performed according to known conditions of the SAP method.

(11) Evaluation of Laminated Body for SAP Evaluation Various characteristics of the obtained laminated body for SAP evaluation were evaluated as follows.

<Plating circuit adhesion (share strength)>
A dry film was laminated to the laminate for SAP evaluation, and exposure and development were performed. After depositing a copper layer having a thickness of 14 μm by pattern plating on the laminate masked with the developed dry film, the dry film was peeled off. The electroless copper plating exposed by the sulfuric acid-hydrogen peroxide etching solution was removed, and a shear strength measurement circuit sample having a height of 15 μm, a width of 10 μm and a length of 150 μm was produced. The shear strength when the shear strength measurement circuit sample was pushed down from the side was measured using a bond strength tester (4000 Plus Bondtester, manufactured by Nordson Dage). That is, as shown in FIG. 6, the stacked body 134 on which the circuit 136 is formed is placed on the movable stage 132 and moved together with the stage 132 in the direction of the arrow in the figure, to the detector 138 fixed in advance. By applying the circuit 136, a lateral force was applied to the side surface of the circuit 136 to push it down, and the force (gf) at that time was measured by the detector 138 and adopted as the shear strength. At this time, the test type was a destructive test, and measurement was performed under the conditions of a test height of 10 μm, a descent speed of 0.050 mm / s, a test speed of 100.0 μm / s, a tool movement amount of 0.05 mm, and a fracture recognition point of 10%. .

<Etching property>
The laminate for SAP evaluation was etched 0.2 μm at a time with a sulfuric acid-hydrogen peroxide etching solution, and the amount (depth) until copper on the surface was completely removed was measured. This measurement was performed by confirming with an optical microscope (500 times). More specifically, every time 0.2 μm etching was performed, the operation of confirming the presence or absence of copper with an optical microscope was repeated, and the value (μm) obtained by (number of times of etching) × 0.2 μm was used as an index of etching property. For example, an etching property of 1.2 μm means that residual copper is no longer detected by an optical microscope after performing 0.2 μm etching six times (ie, 0.2 μm × 6 times = 1.2 μm). ). That is, as this value is smaller, it means that copper on the surface can be removed by a smaller number of etchings. In other words, the smaller the value, the better the etching property.

<Dry film resolution (minimum L / S)>
A dry film having a thickness of 25 μm was laminated on the surface of the laminate for SAP evaluation, and exposure and development were performed using a mask in which a line / space (L / S) pattern of 2 μm / 2 μm to 15 μm / 15 μm was formed. . The exposure amount at this time was set to 125 mJ. The surface of the sample after development is observed with an optical microscope (magnification: 500 times), and the smallest (that is, the finest) L / S in the L / S that can be developed without any problem is adopted as an index for the resolution of the dry film. did. For example, the minimum L / S = 10 μm / 10 μm, which is an index for evaluating the dry film resolution, means that the resolution could be achieved without any problem from L / S = 15 μm / 15 μm to 10 μm / 10 μm. For example, a clear contrast is observed between the dry film patterns when the resolution can be achieved without any problem, whereas a dark portion is observed between the dry film patterns when the resolution is not performed well. Contrast is not observed.

Results The evaluation results obtained in Examples 1 to 3 are as shown in Table 3.

Claims (9)

1. A roughened copper foil having a roughened surface on at least one side, the roughened surface comprising a plurality of roughened particles,
   The average value of the ratio L ² / S of the square of the peripheral length L (μm) of the roughened particles to the area S (μm ² ) of the roughened particles in the cross section having a length of 10 μm of the roughened copper foil is 16 A roughened copper foil having a ten-point average roughness Rz of 0.7 μm or more and 1.7 μm or less, which is 30 or more and 30 or less.
2. The roughened copper foil according to claim 1, wherein the ratio L ² / S is 19 or more and 27 or less.
3. The roughened copper foil according to claim 1 or 2, wherein the number of the roughened particles in a cross section having a length of 10 µm of the roughened copper foil is 20 or more and 70 or less.
4. The roughened copper foil according to any one of claims 1 to 3, which is used for transferring the uneven shape to an insulating resin layer for a printed wiring board.
5. The roughened copper foil according to any one of claims 1 to 4, which is used for production of a printed wiring board by a semi-additive method (SAP).
6. A roughened copper foil according to any one of claims 1 to 5, provided with a carrier, a release layer provided on the carrier, and the roughened surface on the release layer. A copper foil with a carrier.
7. A copper-clad laminate comprising the roughened copper foil according to any one of claims 1 to 5 or the copper foil with a carrier according to claim 6.
8. A printed wiring board obtained by using the roughened copper foil according to any one of claims 1 to 5 or the copper foil with a carrier according to claim 6.
9. A method for producing a printed wiring board, comprising producing a printed wiring board using the roughened copper foil according to any one of claims 1 to 5 or the copper foil with a carrier according to claim 6. .
   
   

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