Copper foil with carrier, copper-clad laminate, and printed wiring board

Abstract

This copper foil is provided with a carrier, which even after high-temperature pressing at above 350°C, can be easily peeled off. This copper foil with a carrier comprises the carrier, an interlayer, and a copper foil in this order, wherein the interlayer comprises a Cr phase, an Ni-P phase, and an Mo-Fe-Ni phase. In the interlayer-side surface of the carrier, the proportion of a surface covered with the Mo-Fe-Ni phase is 61.00-96.00%. In the interlayer, the ratio of the deposited Ni amount to the deposited Mo amount, Ni / Mo, is 2.00 or greater. In the interlayer, the Fe content which is the proportion of the deposited Fe amount to the sum of the deposited Mo amount, the deposited Ni amount, and the deposited Fe amount is 8.90% or less.

Description

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

[0001] The present disclosure relates to a carrier-attached copper foil, a copper-clad laminate, and a printed wiring board.

[0002] Carrier-attached copper foil is widely used as a material for manufacturing printed wiring boards. Carrier-attached copper foil typically comprises a carrier, an intermediate layer (e.g., a release layer), and a copper foil, in this order, and is laminated with an insulating resin substrate by hot pressing to form a copper-clad laminate, which is used in the manufacture of printed wiring boards.

[0003] In recent years, there has been a demand for printed wiring boards suitable for high-frequency applications such as 5G and millimeter waves. For such high-frequency printed wiring boards, reduced transmission loss is desirable to enable transmission of high-frequency signals without degrading their quality. Therefore, to reduce dielectric loss due to insulating resin substrates, high-frequency printed wiring boards use low-dielectric-constant thermoplastic resin substrates, such as polytetrafluoroethylene (PTFE) and liquid crystal polymer (LCP). These thermoplastic resin substrates require temperatures exceeding 350°C for processing. Meanwhile, with conventional carrier-attached copper foils, the peel strength increases with increasing processing temperature. Therefore, at these processing temperatures, there are problems such as a significant increase in peel strength between the substrate and carrier, or the inability to peel the carrier.

[0004] To address this problem, several carrier-attached copper foils with improved high-temperature resistance have been proposed. For example, Patent Document 1 (WO 2009 / 084839) discloses a carrier-attached copper foil comprising a carrier, a release layer, and a copper foil, in which the release layer contains a first metal having releasability, such as Mo or W, and a second metal and a third metal, such as Fe, Co, or Ni, that facilitate coating of the first metal. With such a carrier-attached copper foil, swelling of the release layer does not occur even at high temperatures during the manufacturing process of a printed wiring board, making it possible to easily peel off the carrier. Furthermore, Patent Document 2 (WO 2002 / 024444) discloses a carrier-attached copper foil having a release layer, a diffusion barrier layer, and an electrolytic copper plating layer on the carrier surface in this order, in which a chromium layer or a chromium hydrate oxide layer is used as the release layer, and a CO diffusion barrier layer is used as the diffusion barrier layer. ２ It is disclosed that a predetermined metal layer or metal oxide layer that easily absorbs light of the wavelength oscillated by a gas laser is used. By using such a carrier-attached copper foil, it is possible to produce a copper-clad laminate even from a resin substrate that is produced by casting or pressing at high temperatures.

[0005] WO2009 / 084839WO2002 / 024444

[0006] However, conventional carrier-attached copper foils such as those disclosed in Patent Documents 1 and 2 are still insufficient in terms of high-temperature resistance, and further improvement is desired.

[0007] The present inventors have now discovered that in a carrier-attached copper foil, by interposing an intermediate layer having a Cr phase, a Ni-P phase, and a Mo-Fe-Ni phase between the carrier and the copper foil, and by controlling the Ni / Mo ratio and Fe content of the intermediate layer, as well as the coverage rate of the carrier by the Mo-Fe-Ni phase, within respective predetermined ranges, the carrier can be easily peeled off even after high-temperature pressing at above 350°C.

[0008] Therefore, an object of the present invention is to provide a copper foil with a carrier from which the carrier can be easily peeled off even after high-temperature pressing at over 350°C.

[0009] According to the present disclosure, the following aspects are provided: [Aspect 1] A carrier-attached copper foil comprising, in this order, a carrier, an intermediate layer, and a copper foil, wherein the intermediate layer has a Cr phase, a Ni-P phase, and a Mo-Fe-Ni phase, a proportion of the surface of the carrier facing the intermediate layer that is covered with the Mo-Fe-Ni phase is 61.00% or more and 96.00% or less, a Ni / Mo ratio in the intermediate layer that is a ratio of the Ni coating weight to the Mo coating weight is 2.00 or more, and an Fe content in the intermediate layer that is a proportion of the Fe coating weight to the total amount of the Mo coating weight, the Ni coating weight, and the Fe coating weight is 8.90% or less. [Aspect 2] The carrier-attached copper foil according to Aspect 1, wherein the intermediate layer further has an additional Ni-P phase on the Mo-Fe-Ni phase. [Aspect 3] The carrier-added copper foil according to Aspect 1 or Aspect 2, wherein the proportion of the surface of the carrier facing the intermediate layer that is covered with the Mo—Fe—Ni phase is 65.00% or more and 96.00% or less. [Aspect 4] The carrier-added copper foil according to Aspect 3, wherein the proportion of the surface of the carrier facing the intermediate layer that is covered with the Mo—Fe—Ni phase is 75.00% or more and 96.00% or less. [Aspect 5] The carrier-added copper foil according to any one of Aspects 1 to 4, wherein the Ni / Mo ratio is 3.00 or more and 5.00 or less. [Aspect 6] The carrier-added copper foil according to Aspect 5, wherein the Ni / Mo ratio is 3.50 or more and 5.00 or less. [Aspect 7] The carrier-added copper foil according to any one of Aspects 1 to 6, wherein the Fe content is 1.80% or more and 7.00% or less. [Aspect 8] The carrier-added copper foil according to Aspect 7, wherein the Fe content is 1.80% or more and 5.00% or less. [Aspect 9] The carrier-attached copper foil according to any one of Aspects 1 to 8, further comprising, on the copper foil, at least one layer selected from the group consisting of a roughening layer composed of a plurality of roughening particles, a rust prevention treatment layer, and a silane coupling agent layer. [Aspect 10] A copper-clad laminate comprising the carrier-attached copper foil according to any one of Aspects 1 to 9. [Aspect 11] A printed wiring board comprising the carrier-attached copper foil according to any one of Aspects 1 to 9.[Embodiment 12] A method for producing a printed wiring board, comprising producing a printed wiring board using the carrier-attached copper foil according to any one of embodiments 1 to 9.

[0010] 1 is a schematic cross-sectional view showing one embodiment of a carrier-added copper foil of the present invention. It is an enlarged view of the dashed line portion shown in FIG. 1, showing one embodiment of the Cr phase, Ni—P phase, Mo—Fe—Ni phase, and additional Ni—P phase contained in the intermediate layer. It is a graph plotting the atomic concentration ratio of Cr to Cu, the atomic concentration ratio of P to Cu, and the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu, obtained from the XPS depth profile obtained in Example 7, against the depth from the peeled surface. It is an SEM image of the intermediate layer side surface of the carrier after binarization obtained in Example 3.

[0011] DEFINITIONS The following are definitions of terms or parameters used to define the present invention.

[0012] In this specification, "Cr phase" refers to a region where the atomic concentration ratio of Cr to Cu is 0.006 or more based on the atomic concentration distributions of P, Cr, Fe, Ni, Cu, and Mo obtained from an XPS depth profile of a depth region including the intermediate layer of a carrier-attached copper foil. Furthermore, "Ni-P phase" refers to a region where the atomic concentration ratio of P to Cu is 0.01 or more based on the atomic concentration distributions of P, Cr, Fe, Ni, Cu, and Mo obtained from the XPS depth profile. Furthermore, "Mo-Fe-Ni phase" refers to a region where the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu is 0.2 or more based on the atomic concentration distributions of P, Cr, Fe, Ni, Cu, and Mo obtained from the XPS depth profile. In the analysis of the carrier-attached copper foil of the present invention by XPS, an XPS depth profile of the depth region including the intermediate layer is obtained using an X-ray source with a predetermined beam diameter (e.g., 200 μmφ). Therefore, not only the elements constituting the intermediate layer but also Cu originating from the copper foil or carrier are inevitably observed. Therefore, each of the above-mentioned phases is identified by its atomic concentration ratio relative to Cu. The XPS depth profile of the depth region including the intermediate layer can be obtained by performing elemental analysis by XPS while digging in the depth direction (toward the surface opposite the peeled surface) on the carrier-side peeled surface and the copper foil-side peeled surface after the carrier has been peeled off using ion beam sputtering with an ion gun. Preferred measurement conditions for XPS are shown in the examples below.

[0013] In this specification, the "Ni / Mo ratio" refers to the ratio of the Ni adhesion weight to the Mo adhesion weight in the intermediate layer (=Ni adhesion weight / Mo adhesion weight). Furthermore, the "Fe content" refers to the proportion of the Fe adhesion weight in the total of the Mo adhesion weight, Ni adhesion weight, and Fe adhesion weight in the intermediate layer (=100×Fe adhesion weight / (Mo adhesion weight+Ni adhesion weight+Fe adhesion weight)). The Mo adhesion weight, Ni adhesion weight, and Fe adhesion weight are the weights of Mo, Ni, and Fe present per unit area in the intermediate layer, respectively. The Mo adhesion weight, Ni adhesion weight, and Fe adhesion weight can be calculated by dissolving a predetermined area of ​​the intermediate layer in acid and analyzing the Mo concentration, Ni concentration, and Fe concentration in the resulting solution by ICP atomic emission spectrometry.

[0014] In this specification, the "coating ratio of the carrier with the Mo-Fe-Ni phase" means the ratio of the surface of the carrier on the intermediate layer side that is coated with the Mo-Fe-Ni phase. The coating ratio of the carrier with the Mo-Fe-Ni phase can be measured according to the procedure shown in the examples described later.

[0015] In this specification, the "electrode surface" of the electrolytic copper foil refers to the surface that was in contact with the cathode during the preparation of the electrolytic copper foil.

[0016] Carrier-Attached Copper Foil One embodiment of the carrier-attached copper foil of the present invention is shown in FIGS. 1 and 2. The carrier-attached copper foil 10 shown in FIG. 1 comprises a carrier 12, an intermediate layer 14, and a copper foil 16, in this order. As shown in FIG. 2, the intermediate layer 14 has a Cr phase 14a, a Ni—P phase 14b, and a Mo—Fe—Ni phase 14c. In the intermediate layer 14, the Ni / Mo ratio, which is the ratio of the Ni coating weight to the Mo coating weight, is 2.00 or more. Furthermore, in the intermediate layer 14, the Fe content, which is the ratio of the Fe coating weight to the total of the Mo coating weight, Ni coating weight, and Fe coating weight, is 8.90% or less. In the carrier-attached copper foil 10, the proportion of the surface of the carrier 12 facing the intermediate layer 14 that is covered with the Mo—Fe—Ni phase 14c is 61.00% or more and 96.00% or less. In this way, in the carrier-added copper foil 10, by interposing the intermediate layer 14 having the Cr phase 14a, Ni-P phase 14b, and Mo-Fe-Ni phase 14c between the carrier 12 and the copper foil 16, and by controlling the Ni / Mo ratio and Fe content of the intermediate layer 14, as well as the coverage rate of the carrier by the Mo-Fe-Ni phase 14c, within respective predetermined ranges, the carrier 12 can be easily peeled off even after high-temperature pressing exceeding 350° C. A specific index of the peel strength of the carrier 12, when measured under the conditions shown in the examples described later, is preferably 90.0 gf / cm or less, and more preferably 50.0 gf / cm or less.

[0017] The intermediate layer 14 weakens the peel strength of the carrier 12, ensures stability of that strength, and further functions to suppress interdiffusion that may occur between the carrier 12 and the copper foil 16 during high-temperature press forming. The Cr phase 14a in the intermediate layer 14 contains Cr and typically exists to form an interface with the carrier 12. That is, when the carrier 12 is peeled off after the carrier-attached copper foil 10 and an insulating resin substrate are bonded together, the carrier 12 and the copper foil 16 are typically separated from each other via the Cr phase 14a as the peel surface. The Ni-P phase 14b in the intermediate layer 14 contains Ni and P and contributes to improving the plating properties of the Mo-Fe-Ni phase 14c and the like. Typically, the Ni-P phase 14b is particulate and exists scattered on the carrier 12. The Mo-Fe-Ni phase 14c in the intermediate layer 14 contains Mo, Fe, and Ni and contributes to improving the high-temperature heat resistance of the carrier-added copper foil 10. Typically, the Mo-Fe-Ni phase 14c is particulate and exists so as to embed the particulate Ni-P phase 14b. That is, the Mo-Fe-Ni phase 14c typically exists such that grain growth occurs starting from the Ni-P phase 14b. From the viewpoint of preventing surface oxidation of the Mo-Fe-Ni phase 14c and the like, the intermediate layer 14 preferably further includes an additional Ni-P phase 14d on the Mo-Fe-Ni phase 14c. Typically, the additional Ni-P phase 14d exists so as to cover the outer surface of the particulate Mo-Fe-Ni phase 14c. The thickness of the intermediate layer 14 is typically 50 nm to 500 nm, preferably 100 nm to 350 nm.

[0018] The Ni / Mo ratio in the intermediate layer 14 is 2.00 or more, preferably 3.00 to 5.00, more preferably 3.50 to 5.00, and even more preferably 3.50 to 4.50, by mass. The Fe content in the intermediate layer 14 is 8.90% or less, preferably 1.80% to 7.00%, more preferably 1.80% to 5.00%, and even more preferably 1.80% to 4.50%. Within these ranges, high-temperature resistance can be effectively improved.

[0019] In the carrier-added copper foil 10, the carrier coverage ratio of the Mo-Fe-Ni phase 14c is 61.00% or more and 96.00% or less, preferably 65.00% or more and 96.00% or less, more preferably 75.00% or more and 96.00% or less, and even more preferably 75.00% or more and 90.00% or less. Within such ranges, the Mo-Fe-Ni phase 14c can effectively improve high-temperature resistance. Note that, when the intermediate layer 14 has an additional Ni-P phase 14d, the above-mentioned carrier coverage ratio value refers to a value obtained by measuring and analyzing the carrier 12 after the additional Ni-P phase 14d has been formed.

[0020] The carrier 12 is a support for supporting the copper foil 16 to improve its handleability, and a typical carrier includes a copper layer. Examples of such carriers include copper foil, resin films or glass whose surfaces are metal-coated with copper or the like, and copper foil is preferred. The copper foil may be either rolled copper foil or electrolytic copper foil. The thickness of the carrier is typically 250 μm or less, preferably 9 μm or more and 200 μm or less, and more preferably 9 μm or more and 150 μm or less.

[0021] The copper foil 16 may have any known structure used in carrier-attached copper foils, but is preferably an electrolytic copper foil. The thickness of the copper foil 16 is typically 18 μm or less, preferably 0.1 μm or more and 7.0 μm or less, and more preferably 1.0 μm or more and 3.0 μm or less.

[0022] If desired, the surface of the copper foil 16 may be roughened to form a roughened layer. Providing a roughened layer on the copper foil 16 can improve adhesion with a resin layer during the manufacture of a copper-clad laminate or printed wiring board. This roughened layer comprises a plurality of roughened particles 18, as shown in FIG. 1 , each of which is preferably made of metal particles, more preferably copper particles. The copper particles may be made of metallic copper or a copper alloy. The roughening treatment for forming a roughened surface can be preferably carried out by forming roughened particles of a metal or alloy on the copper foil 16. For example, the roughening treatment is preferably carried out according to a plating method involving at least two plating steps, including a burnt plating step in which fine metal particles are deposited and attached to the metal foil, and a cover plating step in which the fine metal particles are prevented from falling off.

[0023] If desired, the surface of the copper foil 16 may be subjected to a rust-proofing treatment to form a rust-proofing layer. The rust-proofing treatment preferably includes a zinc plating treatment. The zinc plating treatment may be either a zinc plating treatment or a zinc alloy plating treatment, with a zinc-nickel alloy plating treatment being particularly preferred. The zinc-nickel alloy plating 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 deposition ratio in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, and even more preferably 2.7 to 4, by mass. Furthermore, the rust-proofing treatment preferably further includes a chromate treatment, and this chromate treatment is more preferably performed on the surface of the zinc-containing plating after the zinc plating treatment. This can further improve rust prevention. A particularly preferred rust-proofing treatment is a combination of a zinc-nickel alloy plating treatment followed by a chromate treatment.

[0024] If desired, the surface of the copper foil 16 may be treated with a silane coupling agent 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 applying an appropriately diluted silane coupling agent and drying it. Examples of the silane coupling agent include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane, amino-functional silane coupling agents such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-3-(4-(3-aminopropoxy)butoxy)propyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane, mercapto-functional silane coupling agents such as 3-mercaptopropyltrimethoxysilane, olefin-functional silane coupling agents such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane, acrylic-functional silane coupling agents such as 3-methacryloxypropyltrimethoxysilane, imidazole-functional silane coupling agents such as imidazole silane, and triazine-functional silane coupling agents such as triazine silane.

[0025] Therefore, the carrier-added copper foil 10 preferably further comprises at least one layer selected from the group consisting of a roughened layer composed of a plurality of roughening particles 18, a rust-proofing layer, and a silane coupling agent layer on the copper foil 16. For example, when the carrier-added copper foil 10 further comprises a roughened layer, a rust-proofing layer, and a silane coupling agent layer, the order of these layers is not particularly limited, but it is preferable that the roughened layer, the rust-proofing layer, and the silane coupling agent layer are laminated on the copper foil 16 in this order.

[0026] Manufacturing Method of Carrier-Attached Copper Foil The carrier-attached copper foil 10 of the present invention can be manufactured by (1) preparing a carrier 12, (2) forming an intermediate layer 14 on the carrier 12, and (3) forming a copper foil 16 on the intermediate layer 14. An example of a preferred manufacturing method of the carrier-attached copper foil 10 of the present invention will be described below.

[0027] (1) Preparation of Carrier First, a carrier 12 is prepared as a support. A typical carrier 12 includes a copper layer. As described above, examples of such a carrier 12 include copper foil, a resin film or glass whose surface is coated with a metal such as copper, and the like, and copper foil is preferred.

[0028] When an electrolytic copper foil is used as the carrier 12, electrolytic foil formation may be performed using a sulfuric acid-based copper electrolyte under known conditions, and is not particularly limited. From the viewpoint of producing an electrolytic copper foil with a smooth surface, the electrolyte may contain additives such as sulfonates of active sulfur compounds and quaternary ammonium salt polymers having a cyclic structure. Examples of sulfonates of active sulfur compounds used as additives include 3-mercapto-1-propanesulfonate and bis(3-sulfopropyl)disulfide, and examples of quaternary ammonium salt polymers having a cyclic structure include diallyldimethylammonium chloride polymers.

[0029] (2) Formation of Intermediate Layer The intermediate layer 14 is formed on the carrier 12. The intermediate layer 14 is preferably formed by performing various plating treatments on the surface of the carrier 12 to form a Cr phase 14a, a Ni—P phase 14b, and a Mo—Fe—Ni phase 14c in this order, and more preferably by further forming an additional Ni—P phase 14d after the formation of the Mo—Fe—Ni phase 14c.

[0030] The Cr phase 14a is formed using a solution having a Cr concentration of 0.5 g / L or more and 5.0 g / L or less (more preferably 0.5 g / L or more and 2.0 g / L or less, and even more preferably 0.5 g / L or more and 1.0 g / L or less), a pH of 7 or more and 12 or less, at a solution temperature of 5° C. or more and 50° C. or less, and a current density of 0.5 A / dm ２ 20.0A / dm or more ２ less than (more preferably 0.5 A / dm ２ 10.0A / dm or more ２ or less, more preferably 0.5 A / dm ２ 5.0A / dm or more ２It is preferable to carry out the plating treatment under the conditions of a pressure of 2.0 As or more and 50.0 As or less (more preferably, 2.0 As or more and 30.0 As or less, and even more preferably, 2.0 As or more and 20.0 As or less).

[0031] The Ni-P phase 14b is formed using a solution having a Ni concentration of 10.0 g / L or more and 50.0 g / L or less (more preferably 10.0 g / L or more and 30.0 g / L or less, and even more preferably 10.0 g / L or more and 20.0 g / L or less), a P concentration of 5.0 g / L or more and 30.0 g / L or less (more preferably 5.0 g / L or more and 20.0 g / L or less, and even more preferably 5.0 g / L or more and 15.0 g / L or less), and a pH of 1 or more and 5 or less, at a solution temperature of 5° C. or more and 50° C. or less, and a current density of 1.0 A / dm ２ 20.0A / dm or more ２ less than (more preferably 1.0 A / dm ２ 10.0A / dm or more ２ or less, more preferably 1.0 A / dm ２ 5.0A / dm or more ２ It is preferable to carry out the plating treatment under the conditions of a pressure of 2.0 As or more and 50.0 As or less (more preferably, 2.0 As or more and 30.0 As or less, and even more preferably, 2.0 As or more and 20.0 As or less).

[0032] The formation of the Mo-Fe-Ni phase 14c is achieved when the Mo concentration is 1.0 g / L or more and 50.0 g / L or less (more preferably 1.0 g / L or more and 30.0 g / L or less, and even more preferably 1.0 g / L or more and 15.0 g / L or less), the Fe concentration is 0.5 g / L or more and 30.0 g / L or less (more preferably 0.5 g / L or more and 20.0 g / L or less, and even more preferably 0.5 g / L or more and 10.0 g / L or less), and the Ni concentration is 1.0 g / L or more and 50.0 g / L or less. L or less (more preferably 1.0 g / L or more and 30.0 g / L or less, and even more preferably 1.0 g / L or more and 10.0 g / L or less), a sodium citrate concentration of 100 g / L or more and 500 g / L or less (more preferably 100 g / L or more and 300 g / L or less, and even more preferably 100 g / L or more and 200 g / L or less), and a pH of 7 or more and 12 or less, a solution temperature of 5°C or more and 50°C or less, a current density of 30.0 A / dm ２ 70.0A / dm or more ２or less (more preferably 30.0 A / dm ２ 60.0A / dm or more ２ or less, more preferably 30.0 A / dm ２ 50.0A / dm or more ２ It is preferable to carry out the plating treatment under the conditions of a current flow rate of 200 As or more and 1000 As or less (more preferably, 200 As or more and 800 As or less, and even more preferably, 200 As or more and 650 As or less).

[0033] The additional Ni-P phase 14d is formed using the same solution as the Ni-P phase 14b, at a solution temperature of 5°C to 50°C and a current density of 0.2 A / dm ２ 10.0A / dm or more ２ less than (more preferably 0.2 A / dm ２ 5.0A / dm or more ２ or less, more preferably 0.2 A / dm ２ 2.0A / dm or more ２ It is preferable to carry out the plating treatment under the conditions of a pressure of more than 0 As and not more than 20.0 As (more preferably, 0.5 As or more and not more than 10.0 As, and even more preferably, 1.0 As or more and not more than 5.0 As).

[0034] (3) Formation of Copper Foil The copper foil 16 is formed on the intermediate layer 14. For example, the copper foil may be formed by a wet film formation method such as electroless copper plating or electrolytic copper plating, a dry film formation method such as sputtering or chemical vapor deposition, or a combination thereof. Preferably, the copper foil is formed by electrolytic copper plating. The electrolytic foil formation of the copper foil 16 may be performed using a sulfuric acid-based copper electrolytic solution under known conditions, and is not particularly limited.

[0035] If desired, the surface of the copper foil 16 may be subjected to a roughening treatment, a rust prevention treatment, and / or a silane coupling agent treatment to form a roughened layer, a rust prevention treatment layer, and / or a silane coupling agent layer made up of a plurality of roughening particles 18. These treatments are as described above.

[0036] Copper-Clad Laminate The carrier-attached copper foil 10 of the present invention is preferably used to produce a copper-clad laminate for printed wiring boards. That is, according to a preferred embodiment of the present invention, a copper-clad laminate including the carrier-attached copper foil 10 is provided. The copper-clad laminate includes a carrier-attached copper foil 10 having a carrier 12, an intermediate layer 14, and a copper foil 16 in this order, and a resin layer provided on the surface of the copper foil 16 of the carrier-attached copper foil 10 (the surface of the copper foil 16 opposite the intermediate layer 14). The preferred embodiments of the carrier-attached copper foil 10 described above also apply to the carrier-attached copper foil included in a copper-clad laminate. The carrier-attached copper foil 10 may be provided on one or both sides of the resin layer. The resin layer contains a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. Prepreg is a general term for a composite material in which a substrate such as a synthetic resin plate, glass plate, woven glass fabric, nonwoven glass fabric, or paper is impregnated with a synthetic resin. The resin layer may also contain filler particles made of various inorganic particles such as silica and alumina to improve 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 even more preferably 3 μm or more and 200 μm or less. The resin layer may be composed of multiple layers. The resin layer, such as a prepreg and / or a resin sheet, may be provided on the carrier-attached copper foil 10 via a primer resin layer that is applied in advance to the copper foil surface.

[0037] From the viewpoint of providing a copper-clad laminate suitable for high-frequency applications, the resin layer preferably contains a thermoplastic resin, and more preferably, the majority (e.g., 50% by weight or more) or almost all (e.g., 80% by weight or more or 90% by weight or more) of the resin components contained in the resin layer is a thermoplastic resin. Preferred examples of thermoplastic resins include polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyetheretherketone (PEEK), thermoplastic polyimide (PI), polyamideimide (PAI), fluororesin, polyamide (PA), nylon, polyacetal (POM), modified polyphenylene ether (m-PPE), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cycloolefin (COP), and any combination thereof. From the viewpoint of desirable dielectric tangent and excellent heat resistance, more preferred examples of thermoplastic resins include polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP), polyetheretherketone (PEEK), thermoplastic polyimide (PI), polyamideimide (PAI), fluororesin, and any combination thereof. From the viewpoint of low dielectric constant, particularly preferred thermoplastic resins are liquid crystal polymer (LCP) and / or fluororesin. Preferred examples of fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), and any combination thereof.

[0038] Printed Wiring Boards The carrier-attached copper foil 10 of the present invention is preferably used to produce printed wiring boards. That is, according to a preferred embodiment of the present invention, a printed wiring board including the carrier-attached copper foil 10, or a method for producing the same, is provided. The printed wiring board according to this embodiment comprises a layer structure in which a resin layer and a copper layer are laminated in this order. The resin layer is as described above for copper-clad laminates. In any case, known layer structures can be employed for printed wiring boards. Specific examples of printed wiring boards include single-sided or double-sided printed wiring boards in which the copper foil of the present invention is bonded to one or both sides of a prepreg to form a cured laminate and then a circuit is formed thereon, and multilayer printed wiring boards in which these are layered together. Other specific examples include flexible printed wiring boards, COFs, TAB tapes, etc. in which a circuit is formed by forming the copper foil of the present invention on a resin film. Further examples include build-up wiring boards in which a resin-coated copper foil is formed by applying the resin layer to a copper foil, and the resin layer is then laminated on a printed wiring board as an insulating adhesive layer. The copper foil is then used as all or part of the wiring layer to form a circuit using techniques such as the modified semi-additive process (MSAP) or the subtractive process. Also included are build-up wiring boards in which the copper foil is removed and a circuit is formed using the semi-additive process (SAP). Direct build-up on wafers is also used in which lamination of resin-coated copper foil and circuit formation are alternately repeated on a semiconductor integrated circuit. The carrier-attached copper foil 10 of the present invention can also be preferably used in manufacturing methods using a coreless build-up process in which insulating resin layers and conductor layers are alternately laminated without using a so-called core substrate. More advanced examples include antenna elements in which the resin-coated copper foil is laminated on a substrate to form a circuit; electronic materials for panel displays and window glass in which a pattern is formed by laminating the resin-coated copper foil on glass or a resin film via an adhesive layer; and electromagnetic wave shielding films in which a conductive adhesive is applied to copper foil. In particular, the printed wiring board of the present invention is suitable for use as a high-frequency substrate in applications such as automobile antennas, mobile phone base station antennas, high-performance servers, and collision prevention radars, which are used in high-frequency bands with signal frequencies of 10 GHz or higher.

[0039] The present invention will be explained in more detail by the following examples, but the present invention is not limited to the following examples.

[0040] Examples 1 to 14 Copper foils with a carrier, each having a carrier, an intermediate layer and a copper foil in this order, were prepared as follows.

[0041] (1) Preparation of Carrier A copper electrolyte solution having the following composition was used: a sulfuric acid acid copper sulfate solution; a titanium electrode having a surface roughness Ra of 0.20 μm was used as the cathode; a DSA (dimensionally stable anode) was used as the anode; and the solution temperature was 45° C., the current density was 55 A / dm ２ The copper foil was electrolyzed at 8000 kJ / L to obtain an electrolytic copper foil having a thickness of 18 μm as a carrier. <Composition of sulfuric acid acid copper sulfate solution> - Copper concentration: 80 g / L - Sulfuric acid concentration: 260 g / L - Bis(3-sulfopropyl)disulfide concentration: 30 mg / L - Diallyldimethylammonium chloride polymer concentration: 50 mg / L - Chlorine concentration: 40 mg / L

[0042] (2) Formation of Intermediate Layer The obtained carrier was immersed in a sulfuric acid aqueous solution with a sulfuric acid concentration of 100 g / L for 60 seconds to perform surface cleaning, and then an intermediate layer was formed on the electrode surface of the carrier. First, for Examples 1 to 13, chromic acid was dissolved in pure water to achieve the Cr concentration shown in Table 1, and a potassium hydroxide aqueous solution was added to adjust the pH to 10. Using this solution, plating was performed at a solution temperature of 20°C under the conditions of the current density and quantity of electricity shown in Table 1 to form a Cr phase. On the other hand, for Example 14, no Cr phase was formed.

[0043] Thereafter, sodium phosphite pentahydrate and nickel sulfate hexahydrate were dissolved in pure water to give the Ni and P concentrations shown in Table 1, and a sulfuric acid aqueous solution with a sulfuric acid concentration of 300 g / L was added to adjust the pH to 4.0, and plating was performed using this solution at a solution temperature of 30°C and under the conditions of the current density and quantity of electricity shown in Table 1 to form a Ni-P phase. Next, disodium molybdate, nickel sulfate hexahydrate, iron (II) sulfate heptahydrate, and trisodium citrate dihydrate were dissolved in pure water to give the Mo, Fe, Ni, and sodium citrate concentrations shown in Table 1, and 50 mL of ammonia water was further added to 1 L of this solution, and plating was performed using this solution at a solution temperature of 30°C and under the conditions of the current density and quantity of electricity shown in Table 1 to form a Mo-Fe-Ni phase.

[0044] For Examples 1 to 5 and 7 to 14, plating was carried out using the same solution as used for forming the Ni—P phase described above, at a solution temperature of 30° C., under the conditions of the current density and quantity of electricity shown in Table 1, to form an additional Ni—P phase. On the other hand, for Example 6, no additional Ni—P phase was formed.

[0045] (3) Formation of copper foil The carrier on which the intermediate layer was formed was immersed in a solution having the composition shown below, and the solution temperature was 45°C and the current density was 20 A / dm ２ Electroplating was carried out under the conditions of the above, and a copper foil having a thickness of 3 μm was formed on the intermediate layer, thereby obtaining a copper foil with a carrier. <Solution composition> - Copper concentration: 75 g / L - Free sulfuric acid concentration: 150 g / L

[0046] (4) Roughening Treatment The carrier-attached copper foil was immersed in a sulfuric acid aqueous solution with a sulfuric acid concentration of 100 g / L for 30 seconds to perform surface cleaning, and then the copper foil surface of the carrier-attached copper foil was subjected to a two-stage roughening treatment as follows: - The first stage roughening treatment was performed twice. Specifically, a solution with a copper concentration of 10.5 g / L, a free sulfuric acid concentration of 100 g / L, and a solution temperature of 25°C was used, and the current density was 28 A / dm ２ The first electroplating was carried out under the conditions of a current density of 18 A / dm and an electricity amount of 112 As, and then the same solution was used to carry out electroplating. ２The second electroplating was carried out under the conditions of a copper concentration of 65 g / L, a free sulfuric acid concentration of 100 g / L, and a solution temperature of 45°C, with a current density of 4.8 A / dm ２ Electroplating was carried out under the conditions of a charge of 56 As and a quantity of electricity of 56 As.

[0047] (5) Rust Prevention Treatment The carrier-attached copper foil after the roughening treatment was subjected to a rust prevention treatment consisting of a zinc-nickel alloy plating treatment and a chromate treatment. First, a solution containing 1 g / L of zinc, 2 g / L of nickel, and 80 g / L of potassium pyrophosphate was used, and the solution temperature was 40°C, the current density was 0.5 A / dm ２ Then, a zinc-nickel alloy plating treatment was carried out on the roughened layer and the surface of the carrier under the conditions of: pH 12, current density 1 A / dm ２ The zinc-nickel alloy plated surface was then subjected to a chromate treatment under the conditions described above.

[0048] (6) Silane Coupling Agent Treatment An aqueous solution of 6 g / L of 3-aminopropyltrimethoxysilane was adsorbed onto the surface of the copper foil side of the carrier-attached copper foil, and the water was evaporated using an electric heater, thereby carrying out a silane coupling agent treatment. At this time, the silane coupling agent treatment was not carried out on the carrier side.

[0049]

[0050] Evaluation The carrier-attached copper foils produced in Examples 1 to 14 were subjected to the following various evaluations.

[0051] (a) Peel Strength Measurement A PTFE substrate (RO3003 Bondply, manufactured by ROGERS Corporation, thickness 125 μm, 1 ply) was prepared as a fluororesin substrate. The obtained carrier-attached copper foil was laminated to this PTFE substrate so that the surface-treated copper foil side abutted against the substrate, and pressed using a vacuum press under conditions of 2.4 MPa, 370°C, and 30 minutes to produce a copper-clad laminate. A hard substrate (a 300 μm-thick glass epoxy resin substrate that had been heat-cured) was attached and fixed to the PTFE substrate side of the obtained copper-clad laminate with double-sided tape to obtain a measurement sample. The peel strength (gf / cm) when the carrier was peeled from this measurement sample was then measured. The peel strength was measured using a desktop precision universal testing machine (AGS-50NX, manufactured by Shimadzu Corporation) in accordance with JIS C 6481-1996 under the conditions of a peel width of 50 mm, a peel length of 17 mm, and a peel speed of 50 mm / min. This measurement was performed three times for each example, and the average value was used as the measured value. The results are shown in Table 2.

[0052] (b) Measurement of Ni / Mo ratio and Fe content After peeling off the carrier in (a) above, a predetermined area (75 cm) of the peeled surface on the carrier side and the peeled surface on the copper foil side was measured. ２ ) was dissolved in acid, and the concentrations of Ni, Mo, and Fe in the resulting solution were analyzed using an ICP atomic emission spectrometer (PS3520UVDD, manufactured by Hitachi High-Tech Science Corporation). The weights of Ni, Mo, and Fe per unit area were then calculated and used as the Ni adhesion mass, Mo adhesion mass, and Fe adhesion mass in the intermediate layer, respectively. From the resulting adhesion masses, the ratio of the Ni adhesion mass to the Mo adhesion mass (= Ni adhesion mass / Mo adhesion mass) was calculated as the Ni / Mo ratio, and the proportion of the Fe adhesion mass to the total of the Mo adhesion mass, Ni adhesion mass, and Fe adhesion mass (= 100 × Fe adhesion mass / (Mo adhesion mass + Ni adhesion mass + Fe adhesion mass)) was calculated as the Fe content. The results are shown in Table 2.

[0053] (c) Obtaining an XPS depth profile After the carrier was peeled off in (a) above, the release surface on the carrier side and the release surface on the copper foil side were each subjected to ion beam sputtering using an ion gun, while being dug down in the depth direction (the surface opposite the release surface), and an XPS depth profile of the depth region including the intermediate layer was obtained. This elemental analysis was performed using a scanning dual X-ray photoelectron spectrometer (XPS) (PHI Quantes, manufactured by ULVAC-PHI) under the following measurement conditions. (Measurement conditions) - X-ray beam diameter: 200 μmφ - X-ray output: 50 W - X-ray species: monochromatic Al Kα ray - Ion gun settings: ion species Ar gas, acceleration voltage 2 kV, irradiation area 3 mm × 3 mm - Sputtering rate: 3.7 nm / min - Measurement elements and orbitals: P 2p, Cr 3p, Fe 3p, Ni 2p3, Cu 2p3, Mo 3d

[0054] Based on the atomic concentration distributions of P, Cr, Fe, Ni, Cu, and Mo obtained from the XPS depth profiles, the atomic concentration ratio of Cr to Cu, the atomic concentration ratio of P to Cu, and the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu were calculated. As a result, it was confirmed that, for Examples 1 to 13, there were respectively present a region (Cr phase 14a) in which the atomic concentration ratio of Cr to Cu was 0.006 or more, a region (Ni-P phase 14b) in which the atomic concentration ratio of P to Cu was 0.01 or more, and a region (Mo-Fe-Ni phase 14c) in which the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu was 0.2 or more. For reference, Figure 3 shows a graph in which the atomic concentration ratio of Cr to Cu, the atomic concentration ratio of P to Cu, and the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu, obtained from the XPS depth profile in the depth region including the intermediate layer of Example 7, are plotted against depth from the peeled surface. Note that Figure 3 does not contain a P peak corresponding to the additional Ni-P phase 14d. This is thought to be because the additional Ni-P phase 14d thinly covers the particulate Mo-Fe-Ni phase 14c. Meanwhile, in Example 14, it was confirmed that a region in which the atomic concentration ratio of P to Cu was 0.01 or more (Ni-P phase) and a region in which the ratio of the total atomic concentration of Mo, Fe, and Ni to the atomic concentration of Cu was 0.2 or more (Mo-Fe-Ni phase) were present, while no region in which the atomic concentration ratio of Cr to Cu was 0.006 or more (Cr phase) was present.

[0055] (d) Carrier coverage ratio with Mo-Fe-Ni phase A carrier was prepared and an intermediate layer was formed according to (1) and (2) above, while a measurement sample was prepared in which the intermediate layer was exposed without forming a copper foil. Using a Schottky field emission scanning electron microscope (FE-SEM, manufactured by JEOL Ltd., JSM-7900F), the measurement sample was observed from a direction perpendicular to the surface where the intermediate layer was exposed, and SEM images were obtained under the following conditions. (SEM image acquisition conditions) - Observation application: PC-SEM Ver. 7.1.0.2 - Observation conditions: Acceleration voltage 5.0 kV, Tilt 0° - Observation magnification: 20,000x - Image size: 1280 pixels x 1024 pixels - Image adjustment: In the "Image adjustment" menu, "Brightness" was set to 0 and "Gamma correction" to 1.50. "Contrast" was set by aligning the "L" bar with the left end of the waveform obtained from the histogram and the "R" bar with the first peak when viewed from the right side of the waveform.

[0056] The acquired SEM images were analyzed using image analysis software (LUZEX (version 1.60.8.2) manufactured by Nireco Corporation) as follows. In this image analysis, an area of ​​1260 pixels x 940 pixels (= 25.39 μm ) was analyzed by excluding the photographic information area from the acquired SEM images. ２ / field of view) was analyzed. First, "SIN" in "grayscale image processing" was performed once on the SEM image, and then binarization processing was performed with a threshold of 0 as the lower limit and 165 as the upper limit. For reference, the binarized SEM image obtained in Example 3 is shown in Figure 4. In the binarized SEM image, the areas expressed in white were considered to be the Mo-Fe-Ni phase. Next, the binarized SEM image was subjected to the following filter processing steps (1) to (4) in this order. (1) Logical filter SMOOTH, strength 5 (2) Snowball filter ELIMINATE1 W, strength 3 (3) Logical filter CIRCLE, strength 4 (4) Logical filter FILL HOLES

[0057] The above operation was performed in five different fields of view, and the average of the values ​​calculated as the "area ratio" in the filtered SEM images was taken as the ratio of the surface of the carrier on the intermediate layer side that was covered with the Mo-Fe-Ni phase. The results are shown in Table 2.

[0058]

Claims

1. A copper foil with a carrier comprising, in this order, a carrier, an intermediate layer and a copper foil, wherein the intermediate layer has a Cr phase, a Ni-P phase and a Mo-Fe-Ni phase, a ratio of the surface of the carrier facing the intermediate layer that is covered with the Mo-Fe-Ni phase is 61.00% or more and 96.00% or less, a Ni / Mo ratio that is a ratio of the Ni adhesion amount to the Mo adhesion amount in the intermediate layer is 2.00 or more, and an Fe content that is a ratio of the Fe adhesion amount to the total amount of the Mo adhesion amount, the Ni adhesion amount and the Fe adhesion amount in the intermediate layer is 8.90% or less.

2. The copper foil with a carrier according to claim 1, wherein the intermediate layer further comprises an additional Ni-P phase on the Mo-Fe-Ni phase.

3. The copper foil with a carrier according to claim 1 or 2, wherein the ratio of the surface of the carrier on the intermediate layer side that is covered with the Mo-Fe-Ni phase is 65.00% or more and 96.00% or less.

4. The copper foil with a carrier according to claim 3, wherein the ratio of the surface of the carrier on the intermediate layer side that is covered with the Mo-Fe-Ni phase is 75.00% or more and 96.00% or less.

5. The copper foil with a carrier according to claim 1 or 2, wherein the Ni / Mo ratio is 3.00 or more and 5.00 or less.

6. The copper foil with a carrier according to claim 5, wherein the Ni / Mo ratio is 3.50 or more and 5.00 or less.

7. The carrier-attached copper foil according to claim 1 or 2, wherein the Fe content is 1.80% or more and 7.00% or less.

8. The carrier-attached copper foil according to claim 7, wherein the Fe content is 1.80% or more and 5.00% or less.

9. The copper foil with a carrier according to claim 1 or 2, further comprising at least one layer selected from the group consisting of a roughening layer composed of a plurality of roughening particles, a rust prevention layer, and a silane coupling agent layer on the copper foil.

10. A copper-clad laminate comprising the carrier-attached copper foil according to claim 1 or 2.

11. A printed wiring board comprising the carrier-attached copper foil according to claim 1 or 2.

12. A method for producing a printed wiring board, comprising the steps of: producing a printed wiring board using the carrier-attached copper foil according to claim 1 or 2.

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