TWI890685B - Metal laminate and method for manufacturing the metal laminate - Google Patents

Abstract

The present invention provides a polyarylene sulfide resin film capable of forming a metal layer while maintaining both smoothness and adhesion, a metal laminate, a method for producing the polyarylene sulfide resin film, and a method for producing the metal laminate. A polyarylene sulfide resin film comprises a surface having an oxygen content of 10 atomic% to 17 atomic% as determined by X-ray photoelectron spectroscopy (XPS), and an oxygen to carbon atomic ratio (O/C) of 0.10 to 0.25.

Description

Metal laminate and method for manufacturing the same

The present invention relates to a polyarylene sulfide-based resin film, a metal laminate, a method for producing the polyarylene sulfide-based resin film, and a method for producing the metal laminate, which can be suitably used for wiring board applications, circuit material applications, etc.

With the advancement of communications and information processing technologies, the speed and capacity of electrical signals processed in the communications field have increased in recent years. To achieve these higher communication speeds and capacities, the frequency of electrical signals is being increased. However, since high-frequency signals tend to incur greater transmission loss, circuit boards capable of handling these signals are becoming increasingly necessary. Transmission loss can be categorized as conductor loss and dielectric loss, and each must be reduced.

It's known that dielectric loss originates from the insulator layer of a circuit board. The smaller the dielectric constant and dielectric tangent of the insulator layer, the lower the dielectric loss. Furthermore, dielectric loss is proportional to frequency, so higher frequencies are more susceptible to dielectric loss. Consequently, resins with low dielectric constants and dielectric tangents have attracted attention as materials suitable for circuit boards operating at high frequencies. For example, circuit boards using fluorinated films or films called LCPs with low dielectric constants and dielectric tangents are being developed (Patent Document 1).

On the other hand, conductor loss depends on the conductor's resistance, so silver or copper, with their low resistance, are preferably used for the conductor layer that forms the wiring. In addition to laminating metal foil to an insulator, a known method is to form a thin metal layer on a smooth resin by sputter plating to create the conductor layer of the circuit board. Since the conductor layer formed by sputter plating is extremely thin, measuring less than a few hundred nanometers, electrolytic copper or other materials are deposited on top of the sputtered layer to thicken the conductor, and wiring is then processed to create the circuit board (Patent Document 2).

Representative methods for wiring processing include subtractive and semi-additive methods. The subtractive method involves thickening a thin metal layer across the entire surface by electrolytic copper plating. Resist is then applied to only the pattern where wiring is to be formed, leaving the metal layer residual. Unnecessary areas are then etched away using a chemical solution. The semi-additive method involves exposing the metal portion of the wiring pattern to be processed on the thin metal layer, covering the remaining area with a resist layer, and then electroplating the wiring pattern to form a thicker conductive layer. Soft etching is then used to remove the thin metal layer from the areas outside the wiring pattern covered by the resist layer. In either method, etching is essential for wiring formation. If these methods are to be used to accurately form fine patterns, uneven etching of the wiring area will become a problem, so the surface of the conductive layer is required to be smooth.

[Prior Art Documents] [Patent Documents] Patent Document 1: Japanese Patent Application Publication No. 2004-6668 Patent Document 2: Japanese Patent Application No. 4646580

[The problem that the invention aims to solve]

Traditionally, polyimide films have been used in circuit boards due to their high heat resistance. However, polyimide has poor dielectric properties when used in high-frequency bands, and there are concerns about changes in dielectric properties due to moisture absorption. Recently, fluorine films, which have excellent dielectric properties, have attracted attention for circuit boards suitable for high frequencies. However, due to their composition, fluorine films have high releasability and poor adhesion to conductors. Therefore, in order to directly bond a fluorine-based resin insulating layer to a conductive metal foil with sufficient adhesion, Patent Document 1 describes a laminate formed by forming fine protrusions on the surface of the fluorine-based resin insulating layer and roughening one side of the conductive metal foil. However, as mentioned above, since surface smoothness is required to accurately form fine patterns, it is difficult to achieve sufficient performance. In addition, if a semi-additive method is used to form circuits, etching is often performed for a short time in order to etch only a thin metal layer. If the smoothness is poor, there is a problem of copper residue due to uneven roughness. Furthermore, it is known that the current flowing through the conductor is only transmitted at the very surface layer due to the skin effect. Moreover, it is known that when the surface roughness of the conductor is large, the transmission length increases, becoming a resistance and increasing the transmission loss. Therefore, if the interface between the thin film and copper is made rough to improve the adhesion, there is a problem of increased transmission loss and reduced performance.

Therefore, attention was focused on polyarylene sulfide resin films, typified by polyphenylene sulfide (hereinafter sometimes referred to as PPS), as materials with excellent dielectric properties. However, polyarylene sulfide resins also have few surface functional groups, leaving room for improvement in adhesion to the metal layer. A method was needed to maintain smoothness while enhancing adhesion. [Methods used to solve the problem]

A preferred embodiment of the polyarylene sulfide-based resin film of the present invention is a polyarylene sulfide-based resin film having at least one surface thereof having an oxygen atom content of 10 atomic % to 17 atomic % as determined by X-ray photoelectron spectroscopy (XPS), and an oxygen to carbon atomic ratio (O/C) of 0.10 to 0.25.

A preferred embodiment of the metal laminate of the present invention is a metal laminate comprising a metal layer on a polyarylene sulfide-based resin film in contact with the polyarylene sulfide-based resin film, wherein when the metal layer is peeled from the polyarylene sulfide-based resin film under the following conditions, the surface (α-plane) of the metal layer in contact with the polyarylene sulfide-based resin film has a metal atom content of 10 atomic % or less as determined by XPS analysis.

Conditions: A 9μm thick, 10mm wide strip of metal laminated material with its polyarylene sulfide resin film side fixed to a flat plate. At room temperature, 23°C, and 50% humidity, the metal layer was held and peeled at a speed of 100mm/min and an angle of 180°.

A preferred embodiment of the method for producing a polyarylene sulfide-based resin film of the present invention is a method for producing a polyarylene sulfide-based resin film, comprising the steps of: performing plasma treatment at a treatment power density of 0.1 kW·min/m ² to 50 kW·min/m ² in a gas environment with a pressure of 0.1 Pa to 100 Pa.

A preferred embodiment of the present invention's method for manufacturing a metal laminate comprises the following steps: plasma-treating a polyarylene sulfide resin film at a treatment power density of 0.1 kW·min/m² ^to 50 kW·min/ ^m² in a gas atmosphere having a pressure of 0.1 Pa to 100 Pa, followed by depositing a metal layer on the film by vapor phase deposition or laminating a metal foil. [Effects of the Invention]

According to the present invention, a metal laminate that achieves both smoothness and adhesion can be obtained, resulting in a circuit substrate with excellent performance.

[Form used to implement the invention]

The polyarylene sulfide resin film and metal laminate of the present invention are described in further detail below with reference to the drawings.

The polyarylene sulfide resin film of the present invention is a film having a polyarylene sulfide resin as a main component. The so-called main component refers to a component that accounts for 80% by mass or more of the raw materials constituting the film. The polyarylene sulfide resin film can be a single layer or can be laminated with two or more layers. The so-called polyarylene sulfide resin refers to a homopolymer or copolymer having repeating units of -(Ar-S)-. As for Ar, the units shown in the following formulas (1) to (11) can be cited.

( _R1 and _R2 are substituents selected from hydrogen, alkyl, alkoxy, and halogen groups; _R1 and _R2 may be the same or different.) The repeating units of the polyarylene sulfide resin used in the present invention are preferably p-arylene sulfide units represented by formula (1). Representative examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfide, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof, and mixtures thereof. Particularly preferred p-arylene sulfide units are preferably p-phenylene sulfide units from the perspectives of film properties and economic efficiency. In the present invention, from the viewpoints of durability and dimensional stability, it is preferred that the p-phenylene sulfide unit represented by the structural formula (12) below accounts for 75 mol% or more of all repeating units, more preferably 80 mol% or more, and even more preferably 85 mol% or more.

In the polyarylene sulfide-based resin film of the present invention, at least one surface layer preferably has a melting point of 275°C or lower, more preferably 220°C or higher and 275°C or lower, and even more preferably 245°C or higher and 265°C or lower. The "surface layer" herein refers to the outermost layer when the polyarylene sulfide-based resin film comprises two or more layers. Furthermore, when the polyarylene sulfide-based resin film comprises a single layer, the single layer serves as the surface layer.

When the melting point of the surface layer is set below 275°C, two or more layers can be laminated to maintain the overall heat resistance of the polyarylene sulfide resin film. Setting the melting point below 275°C improves adhesion to the metal layer and reduces metal peeling during subsequent circuit processing. From the same perspective, a melting point of 265°C or below is more preferred. Furthermore, lamination of the metal layer allows for processing at lower temperatures, suppresses defects caused by oxidation of the resin or metal, and prevents residual stress and film warping caused by the difference in thermal expansion between the resin and metal. Furthermore, a melting point of 220°C or higher allows for sufficient crystallinity of the polyarylene sulfide resin, resulting in sufficient heat resistance and reduced hygroscopicity. From the same perspective, the melting point is more preferably 245°C or higher. The melting point can be determined by scraping and sampling the surface layer using a differential scanning calorimeter based on the peak temperature of the melting endothermic peak in a DSC chart obtained in accordance with JIS K7121-1987. If multiple peak temperatures are observed, the peak temperature on the lower side is designated as the melting point.

The polyarylene sulfide resin used to achieve a surface layer melting point of 275°C or less preferably comprises 2 to 25 mol%, and more preferably 2 to 15 mol%, of the repeating units in the polyarylene sulfide resin. A copolymerization unit content of 2 mol% or greater allows the polyarylene sulfide resin to have a melting point within the aforementioned range while also providing sufficient processability. Furthermore, a copolymerization unit content of 25 mol% or less allows the polyarylene sulfide resin to have a sufficiently high degree of polymerization, resulting in improved mechanical properties.

Preferred copolymer units are represented by the following formulas (13) to (17).

(Here, X represents an alkylene group, CO, or _SO2 unit.)

(Here, R represents an alkyl group, a nitro group, a phenylene group, or an alkoxy group.) A particularly preferred copolymerized unit is a meta-phenylene sulfide unit. The copolymerization method with the copolymerization component is not particularly limited, but a random copolymer is preferred. The polyarylene sulfide resin composition may contain various additives such as antioxidants, thermal stabilizers, antistatic agents, or anti-caking agents, as long as they do not impair the effects of the present invention.

The polyarylene sulfide resin film of the present invention may also include layers composed of other resins. Examples of resins constituting the laminate include, but are not limited to, polyimide resins, polyamide resins, polyetheretherketone, polyetherimide, polyamideimide resins, polyolefin resins such as polyethylene and polypropylene, polystyrene, polycarbonate, acrylic resins, urethane resins, fluororesins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyketones, and epoxy resins. Furthermore, a mixture of two or more selected from the above and polyarylene sulfide resins may be used.

The thickness of the polyarylene sulfide resin film of the present invention is not particularly limited, but from the perspective of film forming and processability, it is preferably 2 μm to 300 μm, more preferably 5 μm to 180 μm, and even more preferably 25 μm to 150 μm.

The surface roughness Ra of at least one surface of the polyarylene sulfide resin film of the present invention is preferably not less than 0.01 μm and not more than 0.20 μm, and more preferably not less than 0.01 μm and not more than 0.12 μm. Surface roughness Ra is the arithmetic mean roughness defined in JIS B 0601-1994. A surface roughness of not less than 0.01 μm allows the film to slide properly when rolled into a roll, suppressing scratches and wrinkles. A surface roughness of not more than 0.20 μm can reduce the blurring of the pattern of the metal layer forming the circuit due to surface roughness, suppress the generation of copper residues during the etching step, and suppress the increase in transmission loss due to the skinning effect.

Polyarylene sulfide resins have few surface functional groups, leaving room for improvement in adhesion. Therefore, it is necessary to enhance the interaction with the laminated metal layer. The inventors conducted extensive research and discovered that modifying the surface of polyarylene sulfide resin films can improve the adhesion of the surface functional groups. This is explained in detail below.

A preferred embodiment of the polyarylene sulfide resin film of the present invention is that at least one surface has an oxygen atomic content of 10 atomic% to 17 atomic%, and the atomic ratio of oxygen atoms to carbon atoms (O/C) is 0.10 to 0.25, as determined by X-ray photoelectron spectroscopy (XPS). XPS irradiates a sample surface with soft X-rays in an ultra-high vacuum and uses an analyzer to detect photoelectrons released from the surface. It can obtain surface elemental information from the bonding energy of bound electrons within the substance, information on bonding states from the energy shift of each peak, and further quantitative analysis using the peak area ratio. Since XPS analyzes the depth region corresponding to the length (mean free path) that photoelectrons can travel in a substance, surface information of the measured surface can be obtained. The oxygen atoms detected on the thin film surface in the XPS-based analysis are preferably 10 atomic% or more and 17 atomic% or less, and more preferably 11 atomic% or more and 15 atomic% or less. By setting the oxygen atoms to 10 atomic% or more, functional groups that contribute to close adhesion can be secured, and the effect of improving close adhesion with the metal layer can be achieved. From the same point of view, the oxygen atoms are more preferably 11 atomic% or more. Furthermore, by setting the oxygen atoms to 17 atomic% or less, the reduction in close adhesion caused by excessive oxidation of the resin and the oxidation of the directly adjacent metal layer can be suppressed. From the same point of view, the oxygen atoms are more preferably 15 atomic% or less. The atomic ratio of oxygen atoms to carbon atoms (O/C) on the film surface is preferably 0.10 to 0.25, and more preferably 0.15 to 0.23. Setting the O/C ratio to 0.10 or higher allows for the introduction of desired functional groups. From a similar perspective, the O/C ratio is more preferably 0.15 or higher. Furthermore, setting the O/C ratio to 0.25 or lower suppresses surface brittleness due to excessive oxidation and improves adhesion. From a similar perspective, the O/C ratio is more preferably 0.23 or lower.

The polyarylene sulfide resin film of the present invention preferably has a sulfur-to-carbon atomic ratio (S/C) of 0.10 to 0.16, more preferably 0.12 to 0.16, on at least one surface, as measured by X-ray photoelectron spectroscopy (XPS). It is believed that the introduction of oxygen atoms into the polyarylene sulfide resin film is accompanied by the removal of sulfur atoms. Therefore, by setting the S/C ratio of 0.10 or higher, the significant reduction in sulfur due to molecular chain scission, which would weaken the surface layer, can be suppressed, thereby preventing a decrease in adhesion to the metal layer. Setting the S/C ratio to 0.16 or lower provides a sufficient number of functional groups, thereby improving adhesion.

In the polyarylene sulfide resin film of the present invention, when the area of the S2p peak attributable to sulfur atoms detected by X-ray photoelectron spectroscopy (XPS) on at least one surface is set to 100%, the area of the peak attributable to sulfur oxides is preferably 5% to 20%, and more preferably 5% to 15%. During the modification step of the polyarylene sulfide resin film, surface oxidation often proceeds simultaneously with the modification, and oxygen is not only introduced into the ends of the polyarylene sulfide resin backbone but also oxidizes sulfur in relatively reactive sites. However, sulfur oxides do not always contribute to metal adhesion. Therefore, if surface oxidation progresses beyond the required level, it can degrade the resin and adversely affect adhesion. By limiting the peak area attributable to sulfur oxides to 5% or more, functional groups that contribute to close adhesion can be secured. By limiting it to 20% or less, resin degradation due to oxidation can be suppressed, ensuring close adhesion to metals.

XPS analysis of polyarylene sulfide resin films was performed using monochromatic Al Kα _1.2 radiation, with an X-ray diameter of 1 mm and a photoelectron detection angle of 90°. The acquired spectra were smoothed using 11-point smoothing and horizontally calibrated using C1s (CH _x , CC) at 284.6 eV. The composition ratio was calculated from the peak area. Regarding sulfur oxides, the peak area attributable to S2p in the 174-160 eV range was set to 100%, and the peaks were divided into Group 1 (CS, SS), Group 2 (SO), Group 3 (satellite peak, SO _x (2≦x≦4)), and Group 4 (S ^2- ). The ratio was calculated by taking the sum of Groups 2 and 3 as the sulfur oxides.

The method of modifying the surface of the polyarylene sulfide resin film to achieve the above-mentioned preferred surface condition is preferably a method based on plasma treatment, because it is easy to treat the surface uniformly and adjust the surface condition according to the conditions.

Plasma treatment is a method of modifying the surface of a polyarylene sulfide resin film by exposing it to discharge generated by applying a high voltage (DC or AC) between a high voltage application electrode and a counter electrode. Polyarylene sulfide resin films have low polarity and suffer from coating rejection, which prevents them from being fully coated or results in poor adhesion. Various surface treatments have been used to date. Previous surface treatments aimed to increase the polarity of the film surface and improve wettability, with the goal of adding a large number of oxygen atoms using methods such as corona treatment and ozone treatment in the atmosphere. However, when layering metal to improve adhesion, if the film surface is excessively oxidized, there is a risk that the metal will be oxidized at the interface, leading to performance degradation. Furthermore, to increase the number of functional groups introduced into the film surface, it is effective to introduce oxygen by partially severing the bonds in the polyarylene sulfide resin film. However, the inventors' research revealed that if the molecular chain severance is excessive in the film surface, forces are applied to the interface between the metal and the film, which have different physical properties, during the metal laminate formation process. This embrittled film can cause cohesion and failure, making it difficult to achieve sufficient adhesion. In other words, the inventors discovered that existing treatment methods, due to insufficiently controlled surface conditions or embrittled conditions, pose problems in achieving adhesion with the metal layer. The inventors conducted in-depth research and discovered a method for suppressing the brittleness of polyarylene sulfide resin films while simultaneously appropriately severing bonds to effectively obtain functional groups that readily bond to metals. Specifically, the method for producing a polyarylene sulfide resin film of the present invention efficiently achieves the desired surface condition of the polyarylene sulfide resin film. Furthermore, a strong bonding state due to M-O-S bonding in the metal laminate described later can be achieved while simultaneously reducing the number of molecular chains in the polyarylene sulfide resin film, which are fragile due to molecular chain severance and are unable to strongly bond to metals. The following is a detailed description of the method for producing the polyarylene sulfide resin film of the present invention.

A preferred aspect of the method for producing a polyarylene sulfide-based resin film of the present invention, from the perspective of enabling stable and efficient treatment, is to subject the polyarylene sulfide-based resin film to plasma treatment under reduced pressure. The method preferably includes the step of performing the plasma treatment at a treatment power density of 0.1 kW·min/m ² to 50 kW·min/m ² in a gas atmosphere having a pressure of 0.1 Pa to 100 Pa. The pressure of the gas atmosphere during the plasma treatment under reduced pressure is preferably 0.1 Pa to 100 Pa, more preferably 0.1 Pa to 20 Pa, and even more preferably 0.1 Pa to 15 Pa. Setting the pressure above 0.1 Pa allows stable plasma discharge, and since active species with energy suitable for functional group formation are present at an appropriate density, efficient modification is achieved. Setting the pressure below 100 Pa suppresses the reactive species from reacting with each other and deactivating them, providing a sufficient treatment effect on the treated object. From the same perspective, a pressure below 20 Pa is more preferred, and a pressure below 15 Pa is even more preferred.

During plasma treatment, gases can be introduced into the discharge space to adjust the gas environment during plasma treatment to improve treatment efficiency or introduce specific functional groups. Gases used can include argon, _N₂ , He, Ne, _O₂ , _CO₂ , CO, air, water vapor, _H₂ , _NH₃ , and hydrocarbons represented _{by C₄H₂n + ₂} (where n is an integer from 1 to 4), either alone or in combination. The gas used can be selected based on the ease of plasma discharge, the energy of the active species obtained, and the type of functional group to be introduced. For the modification of polyarylene sulfide resin films, it is preferred to include argon or _N₂ , which facilitate plasma discharge and have relatively high active species energy. To facilitate oxygen incorporation, it is preferred to include _O₂ , _CO₂ , or CO. Among these, a mixed gas of argon and _O₂ or argon and _CO₂ is more preferred, and a mixed gas of argon and _O₂ is even more preferred. Furthermore, to prevent excessive surface treatment, the gaseous environment preferably includes at least one member selected from the group consisting of argon, He, Ne, _O₂ , _CO₂ , CO, water vapor, _{H₂ ,} and _{CnH₂n + ₂} (where n is an integer from 1 to 4). When a mixed gas is prepared, it is preferred that the gas contain oxygen atoms at a volume ratio of 50% or more so that a sufficient amount of oxygen can be introduced.

The high-voltage electrode can be of any shape, for example, a rod-shaped electrode that can continuously process while transporting the film, a wide plate-shaped electrode, etc. In addition, in order to enhance the processing strength or reduce damage to the substrate, it can be made into a magnetron electrode or a dielectric-coated electrode. The counter electrode is not particularly limited as long as it can make the film closely contact and process it, but it is preferably a drum-shaped electrode that can support the transport of the film. The high-voltage electrode and the counter electrode do not need to be the same number. For example, if there are two or more high-voltage electrodes for each counter electrode, space can be saved and processing efficiency can be improved. The distance between the electrodes can be appropriately set according to the gas pressure conditions and the treatment intensity. However, from the perspective of improving the adhesion of the polyarylene sulfide film while preventing damage to the film, it is preferably set in the range of 0.05 cm to 30 cm.

The treatment intensity, measured as treatment power density, is preferably between 0.1kW·min/ ^m² and 50kW·min/ ^m² , and more preferably between 0.3kW·min/ ^m² and 15kW·min/ ^m² . The treatment power density here is the product of the discharge power and time, divided by the discharge area. For long film treatment, this is the power input divided by the width of the discharge section and the film treatment speed. A treatment power density of 0.1kW·min/m² or ^higher ensures sufficient energy for modification. From the same perspective, a treatment power density of 0.3kW·min/m² or ^higher is more preferred. By setting the treatment power density to 50kW·min/m² or ^less , damage to the film can be suppressed. From the same perspective, the treatment power density is more preferably 15kW·min/m² or ^less . Regarding plasma treatment conditions, when the pressure is 0.1Pa or more and less than 10Pa, the treatment power density is preferably 0.1kW·min/ ^m² or more and 50kW·min/m² or ^less . When the pressure is 10Pa or more and less than 100Pa, the treatment power density is more preferably 0.3kW·min/m² or ^more and 15kW·min/m² or ^less .

Furthermore, to prevent embrittlement of the polyarylene sulfide resin film due to excessive surface treatment, the oxygen content of at least one surface of the polyarylene sulfide resin film before plasma treatment, as measured by X-ray photoelectron spectroscopy (XPS), is preferably 17 atomic % or less, and the atomic ratio of oxygen to carbon atoms (O/C) is preferably 0.25 or less. From the same perspective and to minimize the number of surface treatments, the oxygen content is more preferably 10 atomic % or less, and the O/C ratio is more preferably 0.1 or less.

The metal laminate of the present invention has a metal layer on a polyarylene sulfide resin film in contact with the polyarylene sulfide resin film. The thickness of the metal layer is preferably not less than 0.05 μm and not more than 30 μm, and more preferably not less than 0.1 μm and not more than 20 μm. A thickness of not less than 0.05 μm can suppress metal oxidation. From the same point of view, the thickness is more preferably not less than 0.1 μm. A thickness of not more than 30 μm makes the metal layer soft and can suppress the generation of cracks or warping of the laminate. From the same point of view, the thickness is more preferably not more than 20 μm. The metal layer can be a single layer or can be laminated with two or more layers.

The main component of the metal layer in the present invention is preferably copper. The term "main component" refers to atoms comprising 60 atomic percent or more of the metal layer. The metal layer deposition method can be appropriately selected based on productivity. Examples include: extruding or coating a polyarylene sulfide resin onto a copper foil; depositing a metal foil onto a polyarylene sulfide resin film; and forming the metal layer using vapor deposition methods such as vacuum evaporation or sputtering. Among these, a preferred embodiment of the metal laminate manufacturing method of the present invention, from the perspective of maintaining productivity and an ideal surface condition suitable for the subsequent polyarylene sulfide resin film, preferably includes the following steps: plasma treating the polyarylene sulfide resin film at a treatment power density of 0.1 kW·min/ ^m² to 50 kW·min/ ^m² in a gas atmosphere with a pressure of 0.1 Pa to 100 Pa, followed by metal deposition by vapor phase deposition or lamination of metal foil. From this perspective, when laminating (bonding) the metal foil to the polyarylene sulfide resin film, a thermal lamination method is more preferably used to directly laminate the film and metal foil. The temperature for thermal lamination, assuming the melting point of the surface layer of the polyarylene sulfide resin film is Tm, is preferably set to Tm-20°C or higher and Tm+50°C or lower, and more preferably Tm-30°C or higher. Setting the thermal lamination temperature to Tm-20°C or higher softens the resin on the film surface and achieves sufficient adhesion. From the same perspective, the temperature is preferably Tm°C or higher. Furthermore, by setting the temperature below Tm + 50°C, the ideal surface condition of the polyarylene sulfide resin film can be maintained, preventing the film from becoming brittle and losing flexibility due to resin decomposition or crosslinking, or becoming susceptible to coagulation and destruction. It also suppresses warping caused by the difference in thermal expansion coefficient between the resin and the metal foil. From the same perspective, the temperature is more preferably below Tm + 30°C.

The lamination pressure is preferably 0.1 MPa to 10 MPa, more preferably 0.5 MPa to 8 MPa, and even more preferably 1.0 MPa to 5 MPa. Setting the pressure to 0.1 MPa or higher allows for sufficient contact and adhesion between the metal and film. From a similar perspective, the pressure is more preferably 0.5 MPa or higher, and even more preferably 1.0 MPa or higher. Furthermore, setting the pressure to 10 MPa or lower can suppress film deformation and prevent problems during lamination, such as resin flow. From a similar perspective, the pressure is even more preferably 8 MPa or lower, and even more preferably 5 MPa or lower.

Vacuum evaporation and sputtering are preferred methods for depositing metal using vapor deposition, both in terms of productivity and maintaining an ideal surface condition for the subsequent polyarylene sulfide resin film. Vacuum deposition follows the surface roughness of the substrate being deposited, making it preferable to use a smooth film, which allows for a smooth metal layer. Vacuum deposition methods include induction heating, resistance heating, laser beam, and electron beam deposition. Electron beam deposition is particularly suitable due to its high film deposition speed. From a productivity perspective, roll-to-roll processing is suitable for film evaporation. However, since the film is exposed to heat during evaporation, it is preferable to cool the film while it is being evaporated using a cooling roll in contact with the backside of the film being evaporated. Cooling suppresses film deformation caused by the heat of evaporation, minimizing stress on the metal layer. This is beneficial for preventing metal layer peeling and maintaining an ideal surface condition for the polyarylene sulfide resin film. For the same reason, the maximum temperature of the polyarylene sulfide resin film during evaporation is preferably below the glass transition temperature of the film's surface layer. When multiple glass transition temperatures are observed on the surface layer of the film, it is preferable to evaporate the metal below the highest temperature. Furthermore, the glass transition temperature can be obtained by using a DSC chart obtained using a differential scanning calorimeter. In the case of sputtering, from the perspective of productivity, roll-to-roll processing can also be appropriately used. Sputtering can use any power source such as DC, AC, or pulse, and can utilize a magnetic field by configuring a magnet in the device, or it can also utilize an ion beam. Examples include magnetron sputtering, dual magnetron sputtering, and ion beam sputtering. From the perspective of productivity and maintaining an ideal surface condition for the subsequent polyarylene sulfide resin film, sputtering is preferably performed at a power output of 5kW or less.

In the present invention, two or more metal layers can be deposited. In particular, in the case of vapor phase deposition, a base metal layer can be deposited to improve adhesion between the film and the metal layer or to prevent migration. When depositing a base metal layer, it is preferred to deposit the base metal on the polyarylene sulfide resin film and deposit a layer containing copper as a main component in contact with the base metal layer. The base metal layer preferably comprises at least one selected from the group consisting of copper, nickel, titanium, and alloys containing at least one of these. From the perspective of preventing oxidation and improving corrosion resistance of the metal layer, it is preferred that the metal layer contain at least one selected from the group consisting of nickel, titanium, and alloys containing at least one of nickel or titanium. When the metal laminate of the present invention is used in a circuit board for high-speed signal transmission, the magnetic nickel can attenuate the signal. Therefore, the base metal layer is preferably made of titanium or an alloy containing titanium. The thickness of the base metal layer is preferably 1 nm to 100 nm, and more preferably 1 nm to 50 nm. By setting the thickness of the base metal layer to 1nm or more, it becomes easier to achieve a uniform effect within the surface, while by setting it to 100nm or less, it is possible to suppress the reduction in the processability of the wiring pattern caused by the different etching rates of the copper layer and the base layer. In addition, when the base metal is a magnetic material and its thickness is thick, there are also problems such as increased loss and signal attenuation in high-speed signal transmission. From the perspective of film thickness accuracy and productivity, the preferred method for forming the base metal layer is vapor phase film deposition represented by sputtering and vacuum evaporation. From the perspective of improving close contact, sputtering, which reaches the film surface with stronger energy, is more preferred. The method for forming the base metal layer and the layer laminated thereon can be the same or different. For example, both the base metal layer and the layer above it can be deposited by sputtering, or the base metal layer can be deposited by sputtering and then a layer deposited thereon by vacuum evaporation. When vapor phase deposition is used to form both layers, each layer can be deposited in two separate passes or continuously. However, since very thin base metal layers are easily oxidized, continuous deposition is preferred to minimize the effects of oxidation. Furthermore, when forming a metal layer using vapor phase deposition, thin films are often used from the perspective of productivity. Therefore, in order to obtain a sufficient metal thickness as a conductor suitable for circuit resistance, the layer obtained by vapor phase deposition can be used as a power supply layer, and a copper layer can be further deposited by plating electrolytic copper.

In the metal layer of the metal laminate of the present invention, the surface roughness Ra of the surface not in contact with the polyarylene sulfide-based resin film is preferably 0.01 μm to 0.20 μm, more preferably 0.01 μm to 0.15 μm, and even more preferably 0.01 μm to 0.10 μm. Surface roughness Ra is the arithmetic mean roughness as defined in JIS B 0601-1994. By directly contacting the polyarylene sulfide-based resin film, which has excellent dielectric properties, with the metal layer, when used as wiring on a circuit board, transmission loss of transmitted signals caused by the skin effect in high-frequency bands can be suppressed. In addition to laminating copper foil, methods for directly bonding a polyarylene sulfide resin film to a metal layer can also include vapor deposition methods such as sputtering or evaporation. In vapor deposition methods, especially evaporation, the metal layer tends to grow along the surface irregularities of the polyarylene sulfide resin film. Therefore, the surface roughness of the surface not in contact with the polyarylene sulfide resin film is strongly affected by the surface roughness of the polyarylene sulfide resin film. Generally, during layer formation, the surface is roughened to enhance adhesion. However, a unique feature of this method is that, despite depositing the metal layer on a smooth substrate, a strong bond is also achieved. By maintaining a surface roughness Ra of 0.01 μm or greater and 0.20 μm or less on the surface of the metal layer not in contact with the polyarylene sulfide-based resin film, transmission loss caused by the skin effect on the surface of the metal layer not in contact with the polyarylene sulfide-based resin film can be suppressed. Furthermore, this configuration allows for practical use as circuit board wiring without requiring a new smoothing step on the metal layer surface, contributing to improved efficiency and reduced environmental impact during the circuit board wiring process.

Metal laminates using conventional polyarylene sulfide resin films have room for improvement in terms of adhesion to the metal layer, and a method for maintaining smoothness while enhancing adhesion is needed. The inventors of the present invention have investigated various surface treatments for polyarylene sulfide resin films and have discovered the ideal cross-sectional state of the polyarylene sulfide resin film within the metal laminate. It has been discovered that chemical bonding is beneficial for maintaining smoothness while maintaining adhesion between the polyarylene sulfide resin film and the metal layer. Therefore, the state of the interface, namely the aforementioned α-plane, greatly contributes to adhesion, and the following describes this state.

Generally speaking, polyarylene sulfide resin films, due to their low polarity, do not readily form chemical bonds, leaving room for improvement in their adhesion to metal layers. To achieve this adhesion, the chemical bonding between the polyarylene sulfide resin film and the metal layer must be enhanced. The inventors discovered that the state of sulfur oxides (SO) and sulfides ( ^S2- ) present on the α-plane significantly influences this adhesion. The mechanism by which these components enhance adhesion to the metal layer is believed to be MOS bonding between sulfur from the polyarylene sulfide resin film and metal atoms M in the metal laminate via oxygen atoms O. For example, in the case of an unmodified polyarylene sulfide resin film, SO is below the detection limit on the surface. Even after metal deposition, SO is not detected even when analyzing the α-plane, indicating that no bond has been formed and the adhesion is considered to be weakened.

A preferred embodiment of the metal laminate of the present invention is a metal laminate having a metal layer on a polyarylene sulfide-based resin film in contact with the polyarylene sulfide-based resin film, wherein when the metal layer is peeled from the polyarylene sulfide-based resin film under the following conditions, the surface (α-plane) of the metal layer in contact with the polyarylene sulfide-based resin film has a metal atom content of 10 atomic % or less as determined by XPS analysis.

Conditions: A 9μm thick, 10mm wide strip of metal laminated polyarylene sulfide resin film was fixed to a flat plate. At room temperature and 50% humidity, the metal layer was held and peeled at a speed of 100mm/min and an angle of 180°.

When XPS-based analysis is performed on the surface of the metal layer peeled from the metal laminate that contacts the polyarylene sulfide-based resin film (α-plane), the metal atoms detected are 10 atomic% or less. This means that a large amount of polyarylene sulfide-based resin film is attached to the peeled metal layer. By keeping the metal atoms on the α-plane at 10 atomic% or less, the metal layer can be sufficiently adhered and peeling during circuit formation can be suppressed. From the same point of view, the metal atoms on the α-plane are more preferably 5 atomic% or less. Furthermore, when two or more types of metal atoms are detected, the total of these is used as the amount of metal atoms. The number of metal atoms detected depends on the composition of the laminate. For example, when the metal layer is a single copper layer, the metal atoms detected are copper. However, when a layer containing titanium is used as the base metal layer and a copper layer is stacked thereon, both titanium and copper are detected.

When the peak area of S2p attributable to sulfur atoms detected in XPS analysis on the α-plane is set to 100%, the peak area attributable to sulfur oxides (SO) is preferably from 1% to 7%, and more preferably from 2% to 5%. By setting the peak area attributable to sulfur oxides (SO) to 1% or more, the surface is sufficiently modified and adhesion is improved. From the same perspective, 2% or more is more preferred. Furthermore, by setting it to 7% or less, the reduction in adhesion caused by deterioration of the polyarylene sulfide resin film can be reduced, and peeling during circuit formation can be suppressed. From the same perspective, 5% or less is more preferred.

When the peak area of the S2p peak attributed to sulfur atoms detected in the α-plane by XPS analysis is set to 100%, the peak area attributed to sulfide ( ^S2- ) is preferably 5% or less, more preferably 3% or less. It is believed that sulfide ( ^S2- ) remains on the surface of the polyarylene sulfide resin film because its molecular chain is broken and it cannot form a functional group that strongly bonds to metal. If the molecular chain is broken under conditions such as the presence of sufficient oxygen, it may become a functional group that promotes close bonding. However, if the required amount of oxygen is not supplied or if it is reduced in molecular weight and remains on the surface, it will not contribute to close bonding and will remain on the surface. The presence of these components, which do not contribute to adhesion, is thought to act as adhesion inhibitors, weakening adhesion due to degradation of the film and metal layer. Therefore, by limiting the peak area attributable to ^S2- to 5% or less, excessive degradation of the polyarylene sulfide resin film, as described above, can be suppressed, thereby reducing peeling during circuit formation. From a similar perspective, the peak area attributable to sulfide ( ^S2- ) is more preferably 3% or less. Furthermore, the lower limit of the peak area attributable to ^S2- is approximately 1%, based on the detection limit of the analysis.

During the fabrication of metal laminates, the film surface can become damaged or thermally oxidized, causing the surface to deteriorate and become brittle. When a metal layer is peeled from a polyarylene sulfide resin film, as viewed from the interface with the metal layer in the depth direction, the peeling interface appears where the polyarylene sulfide resin film is weak, leaving a thin portion of the polyarylene sulfide resin surface attached to the α-plane of the metal layer. When the polyarylene sulfide resin film is brittle, the peeling interface is very close to the metal layer, resulting in a thinner polyarylene sulfide resin layer attached to the metal layer. Therefore, elements that have become part of the metal layer will be detected in XPS analysis. On the other hand, when the metal layer of a polyarylene sulfide resin film remains intact, the film attached to the peeled metal layer becomes thicker, and the amount of elements detected in the metal layer decreases. Furthermore, sulfur atoms may be released due to deterioration of the polyarylene sulfide resin. If these released sulfur atoms exist as sulfide ions, they may form sulfides with the metal, which may inhibit adhesion.

The metal layer can be peeled off according to the method described in the examples. The surface of the metal layer obtained in this manner that contacts the polyarylene sulfide-based resin film is designated as the α-plane, and this surface is analyzed using XPS. Analysis of the α-plane of the metal layer peeled off from the polyarylene sulfide-based resin film uses monochromatic Al Kα _1,2 -ray excitation, with an X-ray diameter of 200 μm and a photoelectron detection angle of 45°. The obtained spectrum is smoothed using 9-point smoothing, horizontally calibrated using C1s (CH _x , CC) at 284.6 eV, and the composition ratio is calculated from the peak area. Regarding S2p, the peak area of the spectrum between 174 and 160 eV was set to 100%, and the spectrum was divided into Group 1 (CS, SS), Group 2 (SO), Group 3 (satellite peak SO _x (2≦x≦4)), and Group 4 (S ^2- ). The area ratio of Group 2 to Group 4 was calculated and set as the composition ratio.

Furthermore, the α-plane was randomly measured at 10 locations, each with a calculation of the composition ratio. Calculated composition ratios at the detection limit were set to 0%. The arithmetic average of the composition ratios at the 10 locations was used as the XPS analysis result for the α-plane.

The metal laminate of the present invention is suitable for use in circuit materials, touch panels, and the like due to its excellent adhesion between the metal layer and the polyarylene sulfide-based resin film and its very smooth surface. For example, in the case of a circuit substrate, the metal layer is patterned to form a wiring circuit. The wiring circuit can be formed using known methods such as subtractive or semi-additive processes. However, when the circuit wiring width is narrow, the semi-additive process is more desirable, as it reduces the wiring width reduction caused by etching. [Example]

The present invention is described below based on embodiments. Furthermore, the present invention is not limited to these embodiments, and these embodiments may be modified and altered based on the spirit of the present invention, and such modifications should not be excluded from the scope of the invention.

[Evaluation Method] (1) Determination of Melting Point of Polyarylene Sulfide-Based Resin Film Any layer to be measured was scraped off using a microplane to obtain a sample. Using a Seiko Instruments DSC (RDC220) as a differential scanning calorimeter and a Seiko Instruments Disc Station (SSC/5200) as a data analyzer in accordance with JIS K7121-1987, 5 mg of the sample was heated from room temperature to 350°C at a rate of 20°C/min on an aluminum container (first run). The sample was removed and rapidly cooled, and then heated from room temperature to 350°C at a rate of 20°C/min (second run). The peak temperature of the endothermic peak of melting confirmed in the second-run DSC chart was set as the melting point (Tm).

(2) Analysis of the polyarylene sulfide resin film surface by X-ray photoelectron spectroscopy (XPS) Analysis by XPS was performed under the following conditions, which are also described in this article. Apparatus: ESCALAB220iXL Excitation X-ray: Monochromatic Al Kα _1,2 ray (1486.6 eV) X-ray diameter: 1 mm Photoelectron escape angle: 90° (detector inclination relative to the sample surface) Smoothing: 11-point smoothing Horizontal axis correction: C1s (CH _x , CC) is 284.6 eV. Measurement location and number of times: Measurements were performed once at each of 10 random locations on the polyarylene sulfide resin film surface, and the composition ratio was calculated for each measurement. The calculated component ratio is set to 0% when it reaches the detection limit. The arithmetic average of the component ratios of the 10 samples is set as the measurement result.

(3) Measurement of the surface roughness of polyarylene sulfide resin films The surface roughness of the films was measured using the arithmetic mean roughness defined in JIS B0601-1994 under the following conditions. Apparatus: Surfcorder ET4000A manufactured by Kosaka Laboratory Co., Ltd. Stylus tip R: 2 μm Measurement area: 500 μm × 500 μm Sample holder: Semi-cylindrical glass included with the apparatus.

(4) Evaluation of Metal Laminates (4-1) Measurement of Surface Roughness of Metal Layers The surface roughness Ra of the metal layer was measured in the same manner as for the thin film in (3) above.

(4-2) XPS analysis of the metal layer (α-plane) peeled from the metal laminate In this evaluation, the metal layer thickness was uniformly set at 9μm. Laminated metal layers with thicknesses less than 9μm were electrolytically plated to a thickness of 9μm. Layers with thicknesses greater than 9μm were polished for adjustment.

The metal layer was peeled off at the interface between the polyarylene sulfide-based resin film and the metal layer within the metal laminate, and the peeled surface on the metal layer side was analyzed. The metal layer was peeled off by fixing a 10mm wide strip of the laminate to a flat plate. The metal layer was held in a 23°C, 50% humidity environment and peeled at a speed of 100mm/min and a 180° angle.

XPS analysis was performed under the following conditions, also described in this document. Apparatus: QuanteraSXM Excitation X-ray: Monochromatic Al Kα _1,2- ray (1486.6 eV) X-ray Diameter: 200 μm Photoelectron Emission Angle: 45° (detector inclination relative to the sample surface) Smoothing: 9-point smoothing Horizontal Axis Calibration: C1s (CH _x , CC) at 284.6 eV Measurement Locations and Number of Measurements: Measurements were taken at 10 random locations on the α-plane, and the composition ratios were calculated for each measurement. Calculated composition ratios at the detection limit were set to 0%. The arithmetic average of the composition ratios at the 10 locations was used as the XPS analysis result for the α-plane.

(5) Determination of the Adhesion Strength of the Metal Layer In the determination of the adhesion strength of the metal layer, the thickness of the metal layer is uniformly set to 12μm. If the thickness of the metal layer of the metal laminate is less than 12μm, it is plated with electrolytic copper. If it is greater than 12μm, the thickness is adjusted by etching or polishing.

The metal laminate was masked with 5mm-wide masking tape and etched with ferric chloride to obtain a 5mm-wide and 100mm-long sample for measurement. The sample was secured to a SUS plate with adhesive tape, and the metal layer was held in place for adhesion measurement under the following conditions. Apparatus: Adhesion and Film Peel Analysis Apparatus VPA-2 Sample Width: 5mm Sample Length: 100mm Peeling Conditions: 90°, 100mm/min Measurement Distance: 75mm

In the resulting profile, the average adhesion force value for peeling distances between 4mm and 50mm is designated as the adhesion force of the metal layer. Adhesion forces of 5N/cm or greater are designated as A, 3N/cm or greater but less than 5N/cm as B, 1.0N/cm or greater but less than 3N/cm as C, 0.1N/cm or greater but less than 1.0N/cm as D, and less than 0.1N/cm as E.

(6) Wiring Pattern Formation Wiring patterns were processed using metal laminates and their processability was evaluated. A was assigned to patterns that could be processed without copper residue, B to patterns that could be processed but had copper residue at the ends of the wiring pattern or between the wiring, C to patterns that could be processed but had copper residue or rough lines at the ends of the wiring pattern, and D to patterns that could not be processed. The pattern processing methods are as follows.

On the metal layer of the metal laminate, a 20μm thick resist layer with a wiring pattern of L/S = 10/10μm was formed using Tokyo Ohka Co., Ltd.'s "PMER (registered trademark)" P-LA900PM. Electrolytic copper was then applied to bring the metal layer thickness to 10μm. Electrolytic copper plating uses a solution containing 50g/L copper sulfate pentahydrate, 200g/L sulfuric acid, 50ppm chlorine, and 2ml/L of Meltex Co., Ltd.'s additives "Copper Gleam (Registered Trademark)" ST-901A and 20ml/L of "Copper Gleam (Registered Trademark)" ST-901B. Plating conditions are set at a current density of 1.0A/ ^dm² using a spray method. After electrolytic copper plating, the anti-plating layer is removed using an alkaline stripping solution, and a hydrogen peroxide-sulfuric acid-based etchant is used to remove the metal layer between the wiring for power supply, thus forming the wiring pattern. Furthermore, when the metal layer includes nickel or titanium as the base metal layer, it is difficult to remove it using a hydrogen peroxide-sulfuric acid etching solution. Therefore, after the copper layer is etched using the above method, the base metal is removed using "Mec Remover" manufactured by MEC Co., Ltd.

[Example 1] A polyarylene sulfide resin film was obtained by plasma treatment on one side of a 100 μm thick biaxially oriented PPS film (Torelina (registered trademark) film #100-3030, manufactured by Toray Industries, Ltd., surface layer melting point 280°C) in an argon atmosphere. Treatment conditions were: an argon atmosphere, a pressure of 0.3 Pa, and a treatment power density of 0.8 kW·min/ ^m² .

On the plasma-treated surface, a 25nm thick base metal layer of Ni/Cr (80/20 molar ratio) was deposited using magnetron sputtering. Next, a 90nm thick layer of copper was deposited using magnetron sputtering to create the metal stack. The sputtering conditions for both Ni/Cr and Cu were: argon gas was introduced to achieve a vacuum of less than 0.2 Pa, and an RF power supply was used at an output of 500W.

[Example 2] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 1, except that a 100 μm thick biaxially stretched PPS film ("Torelina" (registered trademark) manufactured by Toray Industries, Ltd., having a three-layer structure with the side layers having a melting point of 255°C and the center layer having a melting point of 280°C) was used and the plasma treatment atmosphere was set to an Argon/ _O₂ = 50/50 (volume ratio).

[Example 3] Except that the base metal layer was made of Ti, the same procedures as in Example 2 were followed to obtain a polyarylene sulfide-based resin film and metal laminate.

[Example 4] Except that copper was directly sputter-plated on the plasma-treated polyarylene sulfide resin film, the same procedures as in Example 2 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Example 5] A polyarylene sulfide resin film and metal laminate were obtained in the same manner as in Example 2, except that a Ni/Cr base metal layer was formed on the plasma-treated polyarylene sulfide resin film and then copper was deposited by evaporation. Copper was deposited by vacuum evaporation using an electron beam, resulting in a 0.5μm thick copper layer.

[Example 6] A copper foil was thermally laminated to a polyarylene sulfide resin film obtained in the same manner as in Example 2 to produce a metal laminate. The copper foil used was electrolytic copper foil CF-T4X-SV, 12 μm thick, manufactured by Fukuda Metal Co., Ltd. Thermal lamination was performed using a vacuum press manufactured by Kitagawa Seiki Co., Ltd. at 260°C and 4 MPa for 10 minutes.

[Example 7] Except for using an argon atmosphere as the plasma treatment conditions, the same procedures as in Example 2 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Example 8] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 2, except that the plasma treatment conditions were set to an O ₂ gas environment.

[Example 9] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 8, except that the plasma treatment conditions were set to a treatment power density of 0.4 kW·min/m ² .

[Example 10] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 1, except that the plasma treatment conditions were set to a treatment gas atmosphere of Ar/O ₂ = 50/50 (volume ratio) and a treatment power density of 6.0 kW·min/m ² .

[Example 11] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 2 except that the plasma treatment conditions were set to a treatment power density of 3.5 kW·min/m ² .

[Example 12] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 8, except that the plasma treatment conditions were set to a treatment power density of 15 kW·min/m ² .

[Example 13] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 8 except that the plasma treatment conditions were set to a treatment power density of 50 kW·min/m ² .

[Example 14] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 8 except that the plasma treatment conditions were set to a pressure of 0.1 Pa and a treatment power density of 7.0 kW·min/m ² .

[Example 15] Except for changing the plasma treatment pressure to 10 Pa, the same procedures as in Example 8 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Example 16] Except for changing the plasma treatment pressure to 15 Pa, the same procedures as in Example 8 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Example 17] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 2, except that the plasma treatment conditions were set to a CO ₂ gas environment and the treatment power density was set to 1.2 kW·min/m ² .

[Example 18] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 17 except that the plasma treatment was performed under a gas atmosphere of N ₂ /CO ₂ = 90/10 (volume ratio).

[Comparative Example 1] Except that the metal was deposited without plasma treatment, the same procedures as in Example 1 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Comparative Example 2] Except that the metal was deposited without plasma treatment, the same procedures as in Example 6 were followed to obtain a polyarylene sulfide resin film and a metal laminate.

[Comparative Example 3] Example 2 was followed, except that corona treatment was performed instead of plasma treatment, to produce a polyarylene sulfide resin film and a metal laminate. Corona treatment conditions were: using a corona surface modification device manufactured by Kasuga Electric Co., Ltd., with an electrode width of 25 mm, 100 W, and 0.3 m/min for five cycles.

[Comparative Example 4] A polyarylene sulfide resin film and metal laminate were obtained in the same manner as in Example 2, except that sandblasting was performed instead of plasma treatment. The sandblasting was performed using a bead blasting method, using silica sand with an average particle size of 200 μm as an abrasive. The film was then irradiated at a distance of 1 meter, followed by water washing.

[Comparative Example 5] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Example 2 except that the plasma treatment conditions were set to a treatment gas atmosphere of N ₂ /O ₂ = 50/50 (volume ratio) and a pressure of 0.02 Pa.

[Comparative Example 6] A polyarylene sulfide resin film and a metal laminate were obtained in the same manner as in Comparative Example 5, except that the plasma treatment conditions were set to a treatment power density of 15 kW·min/m ² .

The evaluation results of each embodiment and comparative example are shown in Tables 1 and 2.

Furthermore, after obtaining the polyarylene sulfide resin film of Example 1, plasma treatment was performed using an AC power supply with a frequency of 13.56 MHz, an output of 100 W, and a transport speed of 0.5 m/min.

Furthermore, when the biaxially stretched PPS films of 100 μm thickness used in Examples 1 and 2 were sliced into sections approximately half the thickness using a single-edged blade and the cross-sections were analyzed using method (2), the peak area ratio attributable to sulfur oxides (SO) was less than 1% for all films, and the peak area ratio attributable to sulfides (S ^2- ) was also less than 1%.

The peak area attributable to sulfur oxides (SO) in Comparative Example 2 is believed to be relatively large due to oxidation during bonding at high temperatures. In Comparative Example 4, the slag generated by sandblasting was detected in an oxidized state, resulting in a relatively high peak area ratio attributable to sulfur oxides (SO). Furthermore, the relatively high peak area ratio attributable to sulfides ( ^S2- ) in Comparative Examples 1 and 2 is believed to be due to molecular chains being severed in an oxygen-deficient state during the formation of the base metal layer, resulting in slag in a state that is less conducive to bonding. In Comparative Example 4, it is believed that the slag generated by the sandblasting treatment remained on the surface.

[Table 1] film Melting point of surface layer [℃] handle Pressure [Pa] Processing power density [kW・min/m ² ] Surface XPS Surface roughness Ra [μm] Oxygen atoms [atomic%] O/C S/C Peak area ratio attributable to sulfur oxides [%] Example 1 280 Argon plasma 0.3 0.8 12.0 0.14 0.11 8 0.16 Example 2 255 Argon/ _O2 plasma 0.3 0.8 14.2 0.19 0.14 11 0.10 Example 3 255 Argon/ _O2 plasma 0.3 0.8 14.2 0.19 0.14 11 0.10 Example 4 255 Argon/ _O2 plasma 0.3 0.8 14.2 0.19 0.14 11 0.10 Example 5 255 Argon/ _O2 plasma 0.3 0.8 14.2 0.19 0.14 11 0.10 Example 6 255 Argon/ _O2 plasma 0.3 0.8 14.2 0.19 0.14 11 0.10 Example 7 255 Argon plasma 0.3 0.8 12.0 0.16 0.11 12 0.13 Example 8 255 _O2 plasma 0.3 0.8 16.8 0.24 0.15 14 0.21 Example 9 255 _O2 plasma 0.3 0.4 15.4 0.22 0.16 twenty one 0.18 Example 10 280 Argon/ _O2 plasma 0.3 6.0 13.3 0.16 0.13 15 0.14 Example 11 255 Argon/ _O2 plasma 0.3 3.5 14.9 0.21 0.13 13 0.12 Example 12 255 _O2 plasma 0.3 15 16.9 0.24 0.14 14 0.22 Example 13 255 _O2 plasma 0.3 50 17.0 0.25 0.12 twenty two 0.26 Example 14 255 _O2 plasma 0.1 7.0 15.2 0.21 0.14 13 0.22 Example 15 255 _O2 plasma 10 0.8 16.9 0.25 0.15 16 0.20 Example 16 255 _O2 plasma 15 0.8 17.0 0.25 0.16 18 0.12 Example 17 255 _CO2 plasma 0.3 1.2 14.6 0.20 0.15 13 0.10 Example 18 255 N ₂ /CO ₂ plasma 0.3 1.2 10.2 0.12 0.15 6.0 0.11 Comparative example 1 280 No processing - 0 2.3 0.03 0.14 2.3 0.09 Comparative example 2 255 No processing - 0 1.1 0.01 0.16 2.3 0.14 Comparative example 3 255 electric shock - 66.7 17.7 0.26 0.17 25 0.12 Comparative example 4 255 Sandblasting - 0 1.1 0.01 0.16 2.3 0.57 Comparative example 5 255 N ₂ /O ₂ plasma 0.02 0.8 9.6 0.09 0.17 4.9 0.10 Comparative example 6 255 N ₂ /O ₂ plasma 0.02 15 17.5 0.28 0.09 20 0.27

[Table 2] Metal laminate Metal layer bonding strength [N/cm] Pattern processability Metal layer Peeled surface (α surface) XPS Metal layer surface roughness Ra [μm] Metal atomic weight [atomic%] Peak area ratio attributable to SO [%] Peak area ratio attributable to sulfide (S ^2- ) [%] Example 1 NiCr/Cu 7.0 1 5 0.18 C C Example 2 NiCr/Cu 0.8 4 1 0.10 A A Example 3 Ti/Cu 5.0 2 1 0.10 B A Example 4 Cu 6.0 3 4 0.09 B A Example 5 NiCr/Cu(evaporation) 0.8 4 1 0.08 A A Example 6 copper foil 2.0 3 2 0.25 A C Example 7 NiCr/Cu 4.0 3 3 0.15 B B Example 8 NiCr/Cu 2.0 4 5 0.19 B C Example 9 NiCr/Cu 8.0 1 6 0.18 C C Example 10 NiCr/Cu 5.0 5 4 0.13 B B Example 11 NiCr/Cu 1.0 5 2 0.11 A A Example 12 NiCr/Cu 4.0 6 6 0.20 C C Example 13 NiCr/Cu 9.0 9 7 0.24 D C Example 14 NiCr/Cu 5.0 5 4 0.20 B C Example 15 NiCr/Cu 6.0 6 6 0.19 C C Example 16 NiCr/Cu 10.0 7 8 0.11 C B Example 17 NiCr/Cu 3.0 3 2 0.09 A B Example 18 NiCr/Cu 9.0 <1 4 0.10 D B Comparative example 1 NiCr/Cu >10 <1 6 0.12 E D Comparative example 2 copper foil >10 11 5 0.25 E D Comparative example 3 NiCr/Cu >10 14 7 0.18 E D Comparative example 4 NiCr/Cu >10 8 8 0.64 C D Comparative example 5 NiCr/Cu >10 8 7 0.11 E D Comparative example 6 NiCr/Cu >10 10 8 0.25 E D

1: Polyarylene sulfide resin film 2: Metal layer 3: Base metal layer 4: α-surface

Figure 1 is a schematic cross-sectional view showing the structure of a metal laminate. Figure 2 is a schematic view showing the α plane after the metal layer has been peeled off from the metal laminate.

Claims (5)

A metal laminate comprising a metal layer on a polyarylene sulfide resin film in contact with the polyarylene sulfide resin film, wherein the metal layer, when peeled from the polyarylene sulfide resin film under the following conditions, has a metal atom content of 10 atomic % or less on the surface (α surface) in contact with the polyarylene sulfide resin film as determined by XPS analysis. When the peak area of S2p attributable to sulfur atoms detected in the above-mentioned α-plane in the analysis based on XPS is set as 100%, the peak area attributable to sulfur oxide components (SO) is 2% or more and 7% or less, and when the peak area of S2p attributable to sulfur atoms detected in the above-mentioned α-plane in the analysis based on XPS is set as 100%, the peak area attributable to sulfide (S ^2- ) with a peak area of less than 5%. Conditions: A 9μm thick, 10mm wide strip of metal laminated polyarylene sulfide resin film was fixed to a flat plate. The metal layer was held and peeled at a speed of 100mm/min and an angle of 180° in an environment with a temperature of 23°C and a humidity of 50%. The metal laminate of claim 1, wherein the polyarylene sulfide-based resin film comprises two or more layers, and the melting point of the surface layer of the polyarylene sulfide-based resin film in contact with the metal layer is 275°C or less. The metal laminate of claim 1, wherein the main component of the metal layer is copper. The metal laminate of claim 1, wherein the surface roughness Ra of the surface of the metal layer not in contact with the polyarylene sulfide resin film is not less than 0.01 μm and not more than 0.20 μm. A method for manufacturing a metal laminate, as claimed in claim 1, comprising the steps of: subjecting a polyarylene sulfide resin film to plasma treatment at a treatment power density of 0.1 kW·min/ ^m2 to 50 kW·min/ ^m2 in a gas environment having a pressure of 0.1 Pa to 100 Pa, and then laminating the film with metal by vapor phase deposition or laminating metal foil.