TW202233898A - Surface-treated copper foil, copper-cladded laminate plate, and printed wiring board - Google Patents

Abstract

The purpose of the present invention is to provide a surface-treated copper foil with which it is possible to reduce peeling from a substrate and to form a fine-pitched circuit pattern. This surface-treated copper foil has a copper coil, a first surface treatment layer formed on one surface of the copper coil, and a second surface treatment layer formed on the other surface of the copper coil. The ratio of the amount of Ni adhering to the first surface treatment layer relative to the amount of Ni adhering to the second surface treatment layer is 0.01-2.0. The surface-treated copper foil has a tensile strength of 235-290 MPa. The copper coil is made of at least 99.0 mass% of Cu, the balance being unavoidable impurities.

Description

Surface treated copper foil, copper clad laminate and printed wiring board

The present invention relates to a surface-treated copper foil, a copper-clad laminate and a printed wiring board.

In recent years, with increasing demands for miniaturization and higher performance of electronic equipment, fine pitch (miniaturization) of circuit patterns (also referred to as "conductor patterns") is required for printed wiring boards mounted on electronic equipment.

In response to the requirement of the above-mentioned fine pitch, for example, Patent Document 1 discloses "a surface-treated copper foil comprising a copper foil, a first surface-treated layer formed on one side of the copper foil, and another surface formed on the copper foil. For the second surface treatment layer on one side, the ratio of the Ni adhesion amount of the first surface treatment layer to the Ni adhesion amount of the second surface treatment layer is 0.01 to 2", and it is described that by the surface treatment copper foil, it is possible to A circuit pattern with a high etch factor suitable for fine pitching is formed. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2019-81913

In addition, in the printed wiring board with the fine pitch of the circuit pattern as mentioned above, since the circuit pattern has a fine pitch, it turns out that the circuit formed is easier to peel from the base material than the circuit before the fine pitch. In particular, a flexible printed wiring board (hereinafter, also referred to as "FPC") having flexibility is more likely to be peeled off due to the deformation of the printed wiring board during its manufacture and use. Therefore, in the printed wiring board, it is necessary to improve the peeling resistance as well as the fine pitch of the circuit pattern.

Therefore, this invention was made in order to solve the above-mentioned problem, and an object is to provide the surface-treated copper foil and copper clad laminated board which can reduce peeling from a board|substrate and can form the circuit pattern of the fine pitch. Moreover, the objective of this invention is to reduce the peeling from a board|substrate and to provide the printed wiring board which has a circuit pattern with a fine pitch.

In order to solve the above problems, the inventors of the present invention have conducted intensive research and found that in a printed wiring board with a fine-pitch circuit pattern, by increasing the strength of the copper foil, the peeling of the formed circuit from the substrate can be reduced. Thus, the present invention has been completed. That is, the present invention is as follows.

In one embodiment, the surface-treated copper foil of the present invention includes a copper foil, a first surface-treated layer formed on one side of the copper foil, and a second surface-treated layer formed on the other side of the copper foil; the first The ratio of the Ni adhesion amount of the surface treatment layer to the Ni adhesion amount of the second surface treatment layer is 0.01 to 2.0, the tensile strength of the surface treatment copper foil is 235 to 290 MPa, The said copper foil consists of 99.0 mass % or more of Cu and other unavoidable impurities.

In one embodiment, the copper-clad laminate of the present invention includes the above-mentioned surface-treated copper foil and a base material of the above-mentioned first surface-treated layer followed by the above-mentioned surface-treated copper foil.

The printed wiring board of this invention is provided with the circuit pattern formed by etching the said surface-treated copper foil of the said copper clad laminated board in one form.

According to the present invention, it is possible to provide a surface-treated copper foil and a copper-clad laminate capable of reducing peeling from a substrate and forming a fine-pitch circuit pattern. Moreover, according to this invention, the peeling from a board|substrate is reduced, and the printed wiring board which has a fine-pitch circuit pattern can be provided.

Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail, but the present invention is not limited to this embodiment. ＜Surface treated copper foil＞ FIG. 1 is a cross-sectional view (a cross-sectional view of a copper-clad laminate 10 ) showing a state in which the surface-treated copper foil of the present embodiment has been bonded to a substrate. The surface-treated copper foil 1 of the present embodiment includes a copper foil 2 , a first surface-treated layer 3 formed on one surface of the copper foil 2 , and a second surface-treated layer 4 formed on the other surface of the copper foil 2 . Moreover, the copper clad laminated board 10 has the base material 11 of the surface-treated copper foil 1 and the 1st surface-treated layer 3 next to the surface-treated copper foil 1. The surface-treated copper foil 1 of the present embodiment can be used as a printed wiring board mounted on an electronic device or the like, especially a copper foil for a flexible printed wiring board, and is not particularly limited.

The first surface treatment layer 3 and the second surface treatment layer 4 contain at least Ni as an adhesion element. In the surface-treated copper foil 1, the ratio of the Ni adhesion amount of the 1st surface treatment layer 3 with respect to the Ni adhesion amount of the 2nd surface treatment layer 4 is 0.01-2.0, Preferably it is 0.8-1.5. Since Ni is a component that is difficult to dissolve in the etching solution, by setting the ratio of the Ni adhesion amount within the above-mentioned range, when the copper clad laminate 10 is etched, the formation of the first surface treatment layer 3 on the bottom side of the circuit pattern can be promoted. It dissolves and slows down the dissolution of the second surface treatment layer 4 that becomes the top side of the circuit pattern. Therefore, a circuit pattern with a small difference between the top width and the bottom width and a high etching factor can be obtained.

The Ni deposition amount of the first surface treatment layer 3 is not particularly limited as long as the Ni deposition amount ratio is within the above range, but is preferably 20 to 200 μg/dm ² , more preferably 20 to 100 μg/dm ² . The etching factor of a circuit pattern can be stably improved by making the Ni adhesion amount of the 1st surface treatment layer 3 into the said range.

The first surface-treated layer 3 may contain elements such as Zn, Co, and Cr as adhesion elements in addition to Ni. The Zn adhesion amount of the first surface treatment layer 3 is not particularly limited because it depends on the type of the first surface treatment layer 3, but when the first surface treatment layer 3 contains Zn, it is preferably 20 to 1000 μg /dm ² , more preferably 400 to 500 μg/dm ² . By making the Zn adhesion amount of the 1st surface treatment layer 3 into the said range, the etching factor of a circuit pattern can be raised stably.

The Co adhesion amount of the first surface treatment layer 3 is not particularly limited since it depends on the type of the first surface treatment layer 3, but is preferably 1500 μg/dm ² or less, more preferably 0.1 to 500 μg/dm ² , More preferably, it is 0.5 to 100 μg/dm ² . The etching factor of a circuit pattern can be improved stably by making the Co adhesion amount of the 1st surface treatment layer 3 into the said range. In addition, since Co is a magnetic metal, by controlling the adhesion amount of Co in the first surface treatment layer 3 to be 100 μg/dm ² or less, preferably 0.5 to 100 μg/dm ² , it is possible to obtain a high frequency Surface-treated copper foil 1 for printed wiring boards with excellent properties.

The Cr adhesion amount of the first surface treatment layer 3 is not particularly limited since it depends on the type of the first surface treatment layer 3, but is preferably 500 μg/dm ² or less, more preferably 0.5 to 300 μg/dm ² , More preferably, it is 1 to 100 μg/dm ² . By making the Cr adhesion amount of the 1st surface treatment layer 3 into the said range, the etching factor of a circuit pattern can be raised stably.

The Rzjis of the first surface treatment layer 3 is not particularly limited, but is preferably 0.3 to 1.5, more preferably 0.5 to 0.8. By making the Rzjis of the 1st surface treatment layer 3 into the said range, the adhesiveness with the base material 11 can be improved. Here, in this specification, "Rzjis" means the ten-point average roughness specified in JIS B 0601:2001.

The type of the first surface treatment layer 3 is not particularly limited as long as the ratio of the Ni adhesion amount is within the above range, and various surface treatment layers known in the technical field can be used. As an example of the surface treatment layer, a roughening treatment layer, a heat-resistant layer, a rust preventive layer, a chromate treatment layer, a silane coupling treatment layer, etc. are mentioned. These layers may be used alone or in combination of two or more. Among them, it is preferable that the first surface treatment layer 3 has a roughening treatment layer from the viewpoint of the adhesiveness with the base material 11 . Here, in this specification, the "roughening treatment layer" refers to a layer formed by a roughening treatment, and includes a roughened particle layer. In addition, in the roughening treatment, ordinary copper plating or the like may be performed as a pretreatment, or in order to prevent the peeling of the roughened particles, ordinary copper plating or the like may be performed as a finishing treatment, and the "roughening treatment layer" in this specification includes Layers formed from these pretreatments and finishing treatments.

The roughened particles are not particularly limited, and can be formed of any element selected from the group consisting of copper, nickel, cobalt, phosphorus, tungsten, arsenic, molybdenum, chromium, and zinc, or an alloy containing any one or more of them. In addition, after forming the roughened particles, a roughening treatment in which secondary particles or tertiary particles are provided with a simple substance or an alloy of nickel, cobalt, copper, and zinc may be further performed.

It does not specifically limit as a heat-resistant layer and a rust-proof layer, It can be formed from the material well-known in this technical field. Furthermore, since the heat-resistant layer may also function as a rust-proof layer, a single layer having both functions of the heat-resistant layer and the rust-proof layer may be formed as the heat-resistant layer and the rust-proof layer. The heat-resistant layer and/or the anti-rust layer may contain elements selected from the group consisting of nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron , A layer of one or more elements in the tantalum group (which can also be in any form such as metal, alloy, oxide, nitride, sulfide, etc.). As an example of a heat-resistant layer and/or a rust-proof layer, the layer containing a nickel-zinc alloy is mentioned.

It does not specifically limit as a chromate treatment layer, It can be formed from the material well-known in this technical field. Here, in this specification, the "chromate treatment layer" refers to a layer formed using a liquid containing chromic anhydride, chromic acid, dichromic acid, chromate or dichromate. The chromate treatment layer may contain elements such as cobalt, iron, nickel, molybdenum, zinc, tantalum, copper, aluminum, phosphorus, tungsten, tin, arsenic, titanium, etc. any form of things, etc.) layer. Examples of the chromate-treated layer include a chromate-treated layer treated with an aqueous solution of chromic anhydride or potassium dichromate, a chromate-treated layer treated with a treatment solution containing chromic anhydride or potassium dichromate and zinc, and the like. .

It does not specifically limit as a silane coupling process layer, It can be formed from the material well-known in this technical field. Here, in this specification, the "silane coupling treatment layer" refers to a layer formed of a silane coupling agent. It does not specifically limit as a silane coupling agent, A well-known thing in this technical field can be used. As an example of a silane coupling agent, an amino-type silane coupling agent, an epoxy-type silane coupling agent, a mercapto-type silane coupling agent, etc. are mentioned. These can be used alone or in combination of two or more.

The type of the second surface treatment layer 4 is not particularly limited as long as the ratio of the Ni adhesion amount is within the above range, and various surface treatment layers known in the technical field can be used similarly to the first surface treatment layer 3 . In addition, the type of the second surface treatment layer 4 and the first surface treatment layer 3 may be the same or different.

The Ni deposition amount of the second surface treatment layer 4 is not particularly limited as long as the ratio of the Ni deposition amount is within the above-mentioned range, but is preferably 0.1 to 500 μg/dm ² , more preferably 0.5 to 200 μg/dm ² , and more preferably 1.0 to 100 μg/dm ² . By making the Ni adhesion amount of the second surface treatment layer 4 within the above-mentioned range, the etching factor of the circuit pattern can be stably improved.

The second surface treatment layer 4 may contain elements such as Zn and Cr as adhesion elements in addition to Ni. The Zn adhesion amount of the second surface treatment layer 4 is not particularly limited since it depends on the type of the second surface treatment layer 4, but when the second surface treatment layer 4 contains Zn, it is preferably 10 to 1000 μg /dm ² , more preferably 50 to 500 μg/dm ² , still more preferably 100 to 300 μg/dm ² . By making the Zn adhesion amount of the 2nd surface treatment layer 4 into the said range, the etching factor of a circuit pattern can be improved stably.

The adhesion amount of Cr in the second surface treatment layer 4 is not particularly limited since it depends on the type of the second surface treatment layer 4, but when the second surface treatment layer 4 contains Cr, it is preferably more than 0 μg/dm ² However, it is 500 μg/dm ² or less, more preferably 0.1 to 100 μg/dm ² , still more preferably 1 to 50 μg/dm ² . By making the Cr adhesion amount of the second surface treatment layer 4 within the above-mentioned range, the etching factor of the circuit pattern can be stably improved.

The copper foil 2 is composed of 99.0 mass % or more of Cu and other unavoidable impurities, and the tensile strength of the surface-treated copper foil is 235 to 290 MPa. When the copper foil 2 has such a configuration, in the printed wiring board in which the circuit pattern has been finely pitched, peeling of the formed circuit from the base material can be reduced. More specifically, in the case of improving the durability of the circuit pattern (preventing peeling), generally, the improvement of the adhesion to the resin is investigated by adjusting the plating composition or the surface roughness. However, in this embodiment, by setting the copper foil 2 to have the above-mentioned composition, and making the tensile strength of the surface-treated copper foil within a specific range, even in a printed wiring board with finer pitch, it is possible to reduce the Stripping of circuit patterns.

More specifically, in the present embodiment, the method of increasing the tensile strength of the copper foil (furthermore, the surface-treated copper foil) is not limited, and the method of refining the crystal grains after recrystallization of the copper foil is exemplified. In the case of a pure copper-based composition such as copper foil 2, it is difficult to refine the crystal grains, but recrystallization annealing is performed at the initial stage of cold rolling, and recrystallization annealing is not performed after that, so that a large amount of processing strain is introduced by cold rolling. Dynamic recrystallization occurs, and grain refinement can be achieved.

Moreover, with respect to the above-mentioned composition, if the copper foil contains 0.002 to 0.825 mass % in total of one or more additional elements selected from the group consisting of P, Ti, Sn, Ni, Be, Zn, In, and Mg as a refinement of crystal grains The addition of elements makes it easier to realize the miniaturization of the crystal grains. Since these additive elements increase the dislocation density during cold rolling, the grain refinement can be more easily achieved.

Furthermore, as a method for refining the crystal grains after recrystallization of the copper foil, in addition to the method of adding an additive element, a method of lamination, a method of using a pulse current for electrodeposition with an electrolytic copper foil, or a method using The method of adding an appropriate amount of thiourea or glue to the electrolytic copper foil equal to the electrolyte.

The copper foil of the present embodiment may be composed of pure copper (TPC) conforming to JIS-H3100 (C1100) or oxygen-free copper (OFC) conforming to JIS-H3100 (C1011). Moreover, the composition which made the said TPC or OFC contain the said additive element may be sufficient.

In this embodiment, the average grain size of the copper foil is preferably 0.5 to 4.0 μm. If the average grain size is less than 0.5 μm, the tensile strength becomes larger than desired. Specifically, when the strength becomes too high, the flexural rigidity becomes large, so especially when the surface-treated copper foil is used for a flexible printed wiring board, the amount of spring back becomes large, which is not suitable for flexible printing. The tendency of wiring board use. When the average crystal grain size exceeds 4.0 μm, the crystal grains cannot be refined, and the tensile strength becomes smaller than a desired value. Specifically, it becomes difficult to sufficiently increase the strength, and the etching factor and the circuit linearity deteriorate, and the etching property decreases. In order to avoid errors, the measurement of the average grain size was performed by observing the foil surface with a viewing area of 15 μm×15 μm for 10 viewing areas or more. For the observation of the foil surface, SIM (Scanning Ion Microscope) or SEM (Scanning Electron Microscope) can be used, and the average grain size can be determined according to the cutting method described in JIS H 0501. Among them, the twin crystals were measured as separate crystal grains.

In this embodiment, the tensile strength of the surface-treated copper foil is 235-290 MPa. As described above, the tensile strength is improved by refining the crystal grains. During the manufacturing process of the printed wiring board and the assembly of the product, the circuit peeling caused by the external force is accompanied by the deformation of the circuit. In the case of peeling accompanied by such deformation, the range in which the external force is concentrated on the interface varies according to the ease of deformation of the peeled object. In the case of easy deformation, the external force is concentrated in a narrow range on the interface, on the other hand, in the case of difficult deformation, the external force is dispersed in a wide range on the interface. That is, by using the surface-treated copper foil with high strength and not easily deformed as the circuit, the external force can be dispersed in a wide range on the interface, and the circuit peeling can be suppressed. The inventors of the present invention found that, in particular, in a fine-pitch circuit, since the circuit width is narrow, the external force tends to be concentrated, and the dispersion of the external force depending on the difficulty of deformation of the peeling object becomes more important. When the tensile strength of the surface-treated copper foil is less than 235 MPa, the external force on the interface cannot be sufficiently dispersed to prevent circuit peeling. Moreover, when the tensile strength of the surface-treated copper foil exceeds 290 MPa, although circuit peeling can be suppressed sufficiently, the strength becomes too high, and the bending rigidity becomes large. In particular, when the surface-treated copper foil is used for a flexible printed wiring board, there is a tendency that the amount of spring back becomes large and it is not suitable for the use of a flexible printed wiring board. The tensile strength is measured by the tensile test with IPC-TM-650 as the standard, with a test piece width of 12.7 mm, room temperature (15-35°C), tensile speed of 50.8 mm/min, and gauge length of 50 mm. The tensile test is carried out in the direction parallel to the rolling direction (or MD direction) of the copper foil.

In this embodiment, the tensile strength of the surface-treated copper foil after heat treatment at 300° C. for 30 minutes may be 235 to 290 MPa (in other words, the surface-treated copper foil with a tensile strength of 235 to 290 MPa may be 300 ℃ after heat treatment for 30 minutes). The surface-treated copper foil of this embodiment can be used for printed wiring boards. The copper-clad laminate, which is formed by laminating the surface-treated copper foil and a resin as a base material, is heat-treated at 200 to 400° C. to cure the resin. Possibility of grain coarsening due to recrystallization. On the other hand, the surface-treated copper foil of the present embodiment may have a tensile strength of 235 to 290 MPa after heat-treating the surface-treated copper foil at 300° C. for 30 minutes, and its physical properties focus on the surface before being laminated with the resin. The treated copper foil is defined as the state when the above-mentioned heat treatment is performed. The heat treatment at 300° C. for 30 minutes simulates the temperature conditions of curing and heat treatment of the resin during lamination of the copper-clad laminate.

The thickness of the copper foil is not particularly limited. 18 μm.

The copper foil of this embodiment can be manufactured as follows, for example. First, the above-mentioned additives are added to a copper ingot, dissolved, and cast, followed by hot rolling, cold rolling, and annealing, and the above-mentioned final cold rolling, whereby a foil can be produced.

Moreover, the surface-treated copper foil 1 of this embodiment can be manufactured according to the method well-known in this technical field using the above-mentioned copper foil 2. Here, the ratio of the Ni adhesion amount and the Ni adhesion amount of the first surface treatment layer 3 and the second surface treatment layer 4 can be controlled, for example, by changing the type, thickness, etc. of the surface treatment layer to be formed. In addition, the Rzjis of the first surface treatment layer 3 can be controlled by adjusting the formation conditions of the first surface treatment layer 3 and the like.

＜Copper clad laminate＞ The copper-clad laminate 10 of the present embodiment includes the above-mentioned surface-treated copper foil 1 and a base material 11 of the first surface-treated layer 3 attached to the surface-treated copper foil 1 . It does not specifically limit as the base material 11, A well-known thing in this technical field can be used. Examples of the substrate 11 include paper-based phenolic resin, paper-based epoxy resin, synthetic fiber cloth-based epoxy resin, glass cloth-paper composite substrate epoxy resin, glass cloth-glass nonwoven composite substrate Epoxy resin, glass cloth substrate epoxy resin, polyester (polyethylene terephthalate, polyethylene naphthalate, etc.) film, polyimide film, liquid crystal polymer, fluororesin, etc., and , preferably insulating.

It does not specifically limit as a manufacturing method of the copper clad laminated board 10, According to the method well-known in this technical field, it can manufacture by adhering the surface-treated copper foil 1 and the base material 11. For example, the surface-treated copper foil 1 and the base material 11 may be laminated and bonded by thermocompression.

In addition, when the copper-clad laminate of this embodiment is used for a flexible printed wiring board, polyethylene terephthalate, polyimide, polyethylene naphthalate, liquid crystal polymer can be used The film is used as the base material 11, and as a lamination method of the base material 11 and the surface-treated copper foil 1, the material that becomes the base material 11 can also be coated on the surface of the surface-treated copper foil 1 and heated to form a film. Moreover, a resin film may be used as the base material 11, and the following adhesive may be used between the resin film and the surface-treated copper foil 1, or the resin film may be thermocompression-bonded to the surface-treated copper foil 1 without using an adhesive. However, from the viewpoint of not applying excessive heat to the resin film, it is preferable to use an adhesive. When a film is used as the base material 11, the film can be laminated on the surface-treated copper foil 1 through an adhesive. In this case, it is preferable to use an adhesive having the same composition as the film. For example, when a polyimide film is used as the base material 11, it is preferable that a polyimide-based adhesive is also used for the adhesive layer. In addition, the polyimide-based adhesive here refers to an adhesive containing an imide bond, and also includes polyetherimide and the like.

＜Printed wiring board＞ The printed wiring board of the present embodiment includes a circuit pattern formed by etching the surface-treated copper foil 1 of the copper-clad laminate 10 described above. It does not specifically limit as a manufacturing method of a printed wiring board, It can manufacture by a well-known method, and a circuit can be formed in the copper clad laminate 10 using a photolithography technique. Moreover, as needed, a circuit may be plated, and a coverlay film may be laminated to obtain a flexible printed wiring board (flexible wiring board).

As mentioned above, although embodiment of this invention was described, the surface-treated copper foil, copper clad laminated board, and printed wiring board of this invention are not limited to the above-mentioned example, A suitable change can be added. [Example]

Hereinafter, the present embodiment will be described in more detail by way of examples, but the present embodiment is not limited to these examples at all.

It was investigated whether it is possible to manufacture a surface-treated copper foil, attach the surface-treated copper foil to a substrate to obtain a copper-clad laminate, and form a circuit pattern with reduced peeling from the substrate and a finer pitch.

The surface-treated copper foil of each Example and each comparative example was obtained as follows. <Example: Surface-treated copper foil 1> An ingot was produced in a non-oxidizing environment using electrolytic copper. The ratio of copper contained in the ingot was 99.99 mass %. After the ingot is homogenized and annealed at 900° C. or higher, hot rolling is performed, and cold rolling and annealing are performed. After final annealing, final cold rolling was performed to finally obtain a foil with a thickness of 12 μm. Then, a roughening treatment layer, a heat-resistant layer and a chromate treatment layer were sequentially formed on one side of the copper foil sample as the first surface treatment layer, and a heat-resistant layer and a chromium layer were sequentially formed on the other side of the copper foil sample. The acid-acid-treated layer serves as the second surface-treated layer to obtain a surface-treated copper foil. The conditions for forming each layer are as follows. In addition, each physical property of the surface-treated copper foil 1 was evaluated by the method mentioned later, and Table 1 shows the result.・The roughening treatment layer of the first surface treatment layer is formed by electroplating to form a roughening treatment layer. Plating bath composition: 10～20 g/L of Cu, 50～100 g/L of sulfuric acid Plating bath temperature: 25～50℃ Plating conditions: divided into 2 stages applying current Stage 1: current density 45.0 A/dm ² , time 1.4 seconds, coulomb weight 60.8 As/dm ² 2nd stage: current density 4.1 A/dm ² , time 2.8 seconds, coulomb weight 11.8 As/dm ²・The heat-resistant layer of the first surface treatment layer is formed by electroplating Heat resistant layer. Composition of plating solution: Ni of 1～30 g/L, Zn of 1 to 30 g/L pH of plating solution: 2 to 5 Temperature of plating solution: 30 to 50℃ Electroplating conditions: current density 2.1 A/dm ² , The time was 0.7 seconds, the coulomb amount was 1.4 As/dm ² . The chromate-treated layer of the first surface-treated layer was electroplated to form a chromate-treated layer. Composition of plating solution: 1～10 g/L K ₂ Cr ₂ O ₂ , 0.01～10 g/L Zn plating solution pH: 2～5 Plating solution temperature: 30～50℃ Electroplating condition: current density 2.1 A/dm ² , time 1.4 seconds, coulomb weight 2.9 As/dm ² · Heat-resistant layer of the second surface treatment layer A heat-resistant layer was formed by electroplating. Composition of plating solution: Ni of 1～30 g/L, Zn of 1 to 30 g/L pH of plating solution: 2 to 5 Temperature of plating solution: 30 to 50℃ Electroplating conditions: current density 2.1 A/dm ² , Time 0.7 seconds, coulomb amount 1.4 As/dm ²・The chromate-treated layer of the second surface-treated layer is chromated by immersion chromate treatment to form a chromate-treated layer. Composition of chromate solution: K ₂ Cr ₂ O ₂ of 1～10 g/L, Zn of 0.01～10 g/L pH of chromate solution: 2～5 Temperature of chromate solution: 30～50℃

<Comparative example: Surface-treated copper foil 2> The surface-treated copper foil 2 is a copper foil in which the tensile strength of the surface-treated copper foil 1 is lowered. Each physical property of the surface-treated copper foil 2 was evaluated by the method mentioned later, and the result is shown in Table 1.

[Table 1] Thickness (μm) 1st surface treatment layer 2nd surface treatment layer Ni adhesion ratio* Tensile strength (MPa) Ni adhesion amount (μg/dm ² ) Zn adhesion amount (μg/dm ² ) Co adhesion amount (μg/dm ² ) Cr adhesion amount (μg/dm ² ) Ni adhesion amount (μg/dm ² ) Zn adhesion amount (μg/dm ² ) Cr adhesion amount (μg/dm ² ) Example Surface Treatment Copper Foil 1 12 64 470 - 67 63 361 17 1.02 251 Comparative Example Surface-treated copper foil 2 12 65 453 - 63 64 299 19 1.01 153 *: The ratio of the Ni adhesion amount of the first surface treatment layer to the Ni adhesion amount of the second surface treatment layer

The following base materials are next to the above-mentioned surface-treated copper foils 1 and 2. ＜Substrate＞ Use FR-4 substrate (one of glass cloth substrate epoxy resin) as the substrate.

Using the above-mentioned surface-treated copper foil and base material, a copper-clad laminate was obtained in the following manner. <Example 1> A base material was adhered to the surface of the 1st surface-treated layer of the surface-treated copper foil 1, and the copper-clad laminated board 1 was obtained. Specifically, the surface layer base material of the first surface treatment layer of the copper foil was bonded by applying heat treatment at 300° C. for 30 minutes by hot pressing (4 MPa) to obtain a copper clad laminate 1 .

<Comparative Example 1> Except having changed the surface-treated copper foil 1 to the surface-treated copper foil 2, the copper-clad laminated board 2 was obtained by the method similar to Example 1. The peeling strength evaluation mentioned later was performed about the said copper clad laminated board 1, 2, and the result is shown in Table 2.

Each physical property and each evaluation were performed by the following methods.

<Tensile strength of surface-treated copper foil> A heat treatment of 300° C.×30 minutes was applied to the above-mentioned surface-treated copper foil to obtain a surface-treated copper foil sample. With respect to each surface-treated copper foil sample, the tensile strength was measured under the above-mentioned conditions by a tensile test based on IPC-TM-650.

<Measurement of the adhesion amount of each element in the first surface treatment layer and the second surface treatment layer> The adhesion amounts of Ni, Zn, and Co were quantitatively analyzed by atomic absorption spectrophotometer by dissolving each surface treatment layer in nitric acid with a concentration of 20% by mass, and using an atomic absorption spectrophotometer (model: AA240FS) manufactured by VARIAN. to measure. In addition, the adhesion amount of Cr was measured by dissolving each surface treatment layer in hydrochloric acid having a concentration of 7 mass %, and performing quantitative analysis by atomic absorption method in the same manner as described above.

<Peel Strength> The peel strength (ease of peeling) of the copper-clad laminates 1 and 2 was measured in accordance with JIS C 6471 8.1. The test piece used for the measurement is a copper-clad laminate with a circuit of 10 mm width made by using copper chloride circuit etching solution. In addition, in the measurement, the copper foil was peeled off from the substrate, and the copper foil was continuously stretched in the 90° direction, and the lowest value within the range where the load was stable within the measurement length of 10 mm or more was defined as the peel strength. In addition, when the peeling strength is 0.80 kgf/cm or more, it can be estimated that the circuit pattern is difficult to peel off.

[Table 2] Surface treated copper foil substrate Peel strength (kgf/cm) Example 1 Surface treated copper foil 1 FR-4 0.90 Comparative Example 1 Surface treated copper foil 2 FR-4 0.68 [Industrial Availability]

According to the present invention, it is possible to provide a surface-treated copper foil and a copper-clad laminate capable of reducing peeling from a substrate and forming a fine-pitch circuit pattern. Moreover, according to this invention, the peeling from a board|substrate is reduced, and the printed wiring board which has a fine-pitch circuit pattern can be provided.

1: Surface treated copper foil 2: copper foil 3: The first surface treatment layer 4: The second surface treatment layer 10: Copper clad laminate 11: Substrate

1 is a cross-sectional view showing a state in which the surface-treated copper foil of the present embodiment has been bonded to a base material.

1: Surface treated copper foil

2: copper foil

3: The first surface treatment layer

4: The second surface treatment layer

10: Copper clad laminate

11: Substrate

Claims (11)

A surface-treated copper foil comprising copper foil, a first surface-treated layer formed on one side of the copper foil and a second surface-treated layer formed on the other side of the copper foil, the first surface-treated layer The ratio of the Ni adhesion amount to the Ni adhesion amount of the second surface treatment layer is 0.01 to 2.0, and the tensile strength of the surface treated copper foil is 235 to 290 MPa, This copper foil consists of 99.0 mass % or more of Cu and other unavoidable impurities. The surface-treated copper foil of claim 1, wherein the ratio of the Ni adhesion amount is 0.8 to 1.5. The surface-treated copper foil according to claim 1 or 2, wherein the Ni adhesion amount of the first surface-treated layer is 20 to 200 μg/dm ² . The surface-treated copper foil according to claim 1 or 2, wherein the Zn adhesion amount of the first surface-treated layer is 20 to 1000 μg/dm ² . The surface-treated copper foil according to claim 1 or 2, wherein the Rzjis of the first surface-treated layer is 0.3 to 1.5. The surface-treated copper foil as claimed in claim 1 or 2, wherein the copper foil is made of pure copper conforming to JIS-H3100 (C1100) or oxygen-free copper of JIS-H3100 (C1011). The surface-treated copper foil according to claim 1 or 2, wherein the copper foil further contains 0.002 to 0.825 mass % in total of at least one selected from the group consisting of P, Ti, Sn, Ni, Be, Zn, In, and Mg of added elements. The surface-treated copper foil of claim 1 or 2, wherein the surface-treated copper foil with a tensile strength of 235-290 MPa is the surface-treated copper foil when heat-treated at 300° C. for 30 minutes. The surface-treated copper foil according to claim 1 or 2, wherein the first surface-treated layer is attached to the base material. A copper-clad laminate comprising the surface-treated copper foil as claimed in claim 1 or 2 and a base material of the first surface-treated layer attached to the surface-treated copper foil. A printed wiring board provided with a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate as claimed in claim 10.

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