WO2023053620A1 - Metal-clad laminate, and laminate used for said metal-clad laminate - Google Patents

Abstract

Provided is a metal-clad laminate which adheres even to a low-dielectric substrate film having poor adhesion, and which has good adhesion to a metal layer formed by a dry process such as vapor deposition or sputtering, or a wet process such as plating.　The present invention also provides a laminate which is used to form said metal-clad laminate, and in which a resin layer is formed on a substrate film.　The laminate has: a substrate film; and a layer composed of a resin composition containing a silane coupling agent, wherein the layer composed of the resin composition has a surface roughness (Rz) of at most 1 µm, and the laminate has a relative permittivity of at most 3.5 and a dielectric loss tangent of at most 0.005 under the frequency condition of 28 GHz.

Description

Metal-clad laminate and laminate used for the metal-clad laminate

The present invention relates to a metal-clad laminate and a laminate used for the metal-clad laminate.

In recent years, with the increase in communication speed and capacity in communication devices such as smartphones, the circuit boards used in these communication devices are required to have lower electrical signal loss, finer pitch circuit patterns, and higher precision. Therefore, fine circuit formation is demanded.
Metal-clad laminates (e.g., copper-clad laminates (CCL)) in which a metal film is placed and laminated on the surface of a base film made of a so-called insulating resin, which is the main material of a circuit board, also have the above-mentioned properties. Performance similar to that of circuit boards is required.
Various improved metal-clad laminates (for example, copper-clad laminates (CCL)) have been proposed (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2011-14801

Printed wiring boards including metal-clad laminates are required to transmit a large amount of data at high speed as described above, and are becoming increasingly compatible with high frequencies. It is necessary to reduce the transmission loss of high frequencies for printed wiring boards to support high frequencies. Realization of a conductor is required.
As a method of realizing a conductor with a low surface roughness, there is a method of forming a conductor on the surface of a low dielectric base material by a dry process such as vapor deposition or sputtering, or a wet process such as plating. Compared to the method of thermocompression bonding a metal foil (e.g., copper foil) with a certain surface roughness, these methods are less smooth because the surface roughness of the conductor depends on the surface roughness of the base film. Using a high base film can reduce the surface roughness of the conductor.
However, the low dielectric base film requires high processing temperature and adjustment of resin orientation in order to develop heat resistance, and the poor workability makes it impossible to produce a smooth low dielectric base film. Furthermore, since the resin constituting the low-dielectric base film is composed of a molecular skeleton with low polarity, it is difficult to develop adhesion with a metal layer formed by a dry process such as vapor deposition or sputtering, or a wet process such as plating. In addition, when the smoothness of the low-dielectric substrate film is increased, there is a possibility that this adhesion will be further reduced.
Therefore, it is desired to provide a metal-clad laminate that can reduce the transmission loss of electrical signals and has excellent adhesion between the metal film and the substrate film.

The present invention provides a metal-clad laminate that adheres even to a low-dielectric substrate film with poor adhesion, and has good adhesion to metal layers formed by dry processes such as vapor deposition and sputtering, or wet processes such as plating. The purpose is to provide a board.
Another object of the present invention is to provide a laminate in which a resin layer is formed on a substrate film, which is used for forming the metal-clad laminate.

The present inventors have made intensive studies to solve the above problems, and found that a resin composition containing a silane coupling agent having a specific surface roughness (Rz) between a metal film and a base film The inventors have found that the above problem can be solved by arranging different layers, and have completed the present invention.

The present invention includes the following aspects.
[1] A laminate having a base film and a layer made of a resin composition containing a silane coupling agent,
The surface roughness (Rz) of the layer made of the resin composition is 1 μm or less,
A laminate having a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.005 or less under the condition of a frequency of 28 GHz.
[2] The laminate according to [1], wherein the surface roughness (Rz) is 0.5 μm or less.
[3] The laminate according to [1] or [2], wherein the silane coupling agent is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin composition.
[4] The silane coupling agent is a silane coupling agent containing any one of functional groups selected from imidazole skeleton, triazole skeleton, triazine skeleton, olefin skeleton, mercapto group, maleic anhydride skeleton, imide skeleton, and amino group. , the laminate according to any one of [1] to [3].
[5] The laminate according to any one of [1] to [4], wherein the silane coupling agent has a melting point of 100° C. or less.
[6] The laminate according to any one of [1] to [5], wherein the silane coupling agent is a silane coupling agent having a butadiene skeleton.
[7] The laminate according to any one of [1] to [6], wherein the resin composition further contains a maleimide resin.
[8] The laminate according to [7], wherein the maleimide resin has a weight average molecular weight of 5,000 to 100,000.
[9] The laminate according to [8], wherein the maleimide resin has a weight average molecular weight of 5,000 to 40,000.
[10] The laminate according to any one of [1] to [9], wherein the resin composition further contains oxazine.
[11] The laminate according to any one of [1] to [10], wherein the layer comprising the resin composition is a cured film obtained by curing a coating film comprising the resin composition.
[12] The laminate according to any one of [1] to [11], wherein the layer made of the resin composition has a thickness of 20 μm or less.
[13] The laminate according to any one of [1] to [12], wherein the base film has a surface roughness (Rz) of 1 to 4 μm.
[14] The laminate according to any one of [1] to [13], wherein the base film contains a filler.
[15] The laminate according to [14], wherein the filler has an average particle size of 20 µm or less.
[16] The laminate according to [14] or [15], wherein the filler contains at least one of mica, talc, boron nitride (BN) and silica.
[17] The laminate according to any one of [14] to [16], wherein the filler has a plate-like shape.
[18] Any one of [1] to [17], wherein the mass ratio (Si/C) of Si element to carbon atoms on the surface of the substrate film is 3% or more as measured by an electron probe microanalyzer (EPMA). The laminate according to any one of the above.
[19] The laminate according to any one of [1] to [18], wherein the base film contains a polyarylene ether ketone (PAEK) resin.
[20] A metal-clad laminate obtained by laminating a metal film on a layer made of the resin composition of the laminate according to any one of [1] to [19],
A metal-clad laminate, wherein the metal film is a metal film formed by at least one of plating, sputtering, and vapor deposition.
[21] The metal-clad laminate according to [20], wherein the metal film is a copper metal film.
[22] A printed wiring board comprising the laminate according to any one of [1] to [19].
[23] A shielding film comprising the laminate according to any one of [1] to [19].
[24] A printed wiring board with a shield film comprising the laminate according to any one of [1] to [19].

According to the present invention, even a low-dielectric base film with poor adhesion adheres well to a metal layer formed by a dry process such as vapor deposition or sputtering, or a wet process such as plating. A tension laminate can be provided.
Moreover, according to the present invention, it is possible to provide a laminate in which a resin layer is formed on a substrate film, which is used for forming the metal-clad laminate.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of a structure of the metal-clad laminated board of this invention. FIG. 3 is a cross-sectional view showing another example of the configuration of the metal-clad laminate of the present invention;

Hereinafter, the laminate of the present invention and the metal-clad laminate of the present invention formed using the laminate will be described in detail. It is an example and is not specified by these contents.
The following term definitions apply throughout the specification and claims.
The film thickness of the substrate film, the layer made of the resin composition, the metal film, etc. is the average value obtained by observing the cross section of the object to be measured using a microscope, measuring the thickness at five locations, and averaging the values.

(Laminate)
The laminate of the present invention has a base film and a layer made of a resin composition containing a silane coupling agent.
The surface roughness (Rz) of the layer made of the resin composition is 1 μm or less.
The laminate has a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.005 or less under the condition of a frequency of 28 GHz.

<Base film>
In the present invention, the base film is not particularly limited and can be appropriately selected depending on the intended purpose. Resins with excellent dielectric properties include polyarylene ethers such as polyetheretherketone (PEEK) resin, polyetherketone (PEK) resin, polyetherketoneketone (PEKK) resin, and polyetherketoneetherketoneketone (PEKEKK) resin. Ketone (PAEK) resin, polyimide, modified polyimide, polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene - Ethylene copolymer (ETFE), polyphenylene sulfide (PPS), polyphenylene ether (PPE), syndiotactic polystyrene (SPS), aramid, polyethylene naphthalate, and liquid crystal polymer (LCP).
Among these, from the viewpoint of heat resistance and electrical properties, polyarylene ether ketone (PAEK) resin such as polyether ether ketone (PEEK) resin, modified polyimide, polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether Copolymers (PFA), polyphenylene sulfide (PPS), and liquid crystal polymers (LCP) are preferred. Polyarylene ether ketone (PAEK) resin and liquid crystal polymer (LCP) are more preferable from the viewpoint of excellent dimensional stability. A polyether ether ketone (PEEK) resin is more preferable because it has good filler dispersibility and can be compatible with other properties even when the storage elastic modulus of the base film is adjusted by changing the amount of filler added.
An alloy in which a plurality of resins are mixed can be used for the base film.
The base film can contain a filler. The filler will be described in detail below.

<<Filler>>
The base film can contain a filler in order to impart various functions such as strength, insulation, heat resistance, coefficient of thermal expansion (CTE), and adjustment of storage elastic modulus to the base. Examples of fillers include inorganic fillers and organic fillers, which can be used alone or in combination.

Examples of inorganic fillers include mica, talc, boron nitride, magnesium oxide, silica, diatomaceous earth, titanium oxide, and zinc oxide. Inorganic fillers such as mica, talc, boron nitride, magnesium oxide, and silica are preferred from the viewpoint of imparting the above functions without deteriorating the dielectric loss tangent.

Examples of organic fillers include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, olefin polymer, polyamide, polycarbonate, polyimide, polyether ketone, polyether ether ketone, polymethyl methacrylate, liquid crystal polymer, poly Examples include organic particles such as tetrafluoroethylene. Polystyrene, olefin polymer, liquid crystal polymer, and polytetrafluoroethylene are preferred from the viewpoint of improving the dielectric properties of the base film.

One of the inorganic fillers and organic fillers may be selected from the above and used alone, or two or more may be used in combination. When two or more types are combined, a combination of an inorganic filler and an organic filler may be used.

The shape of the filler is not particularly limited and can be appropriately selected depending on the purpose. For example, the filler may be a spherical filler or a non-spherical filler, but from the viewpoint of coefficient of thermal expansion (CTE), a non-spherical filler is preferred. The shape of the non-spherical filler may be any three-dimensional shape other than a spherical shape (substantially spherical shape), and examples thereof include plate-like, scale-like, columnar, chain-like, and fibrous shapes. Among them, plate-like and scale-like fillers are preferable, and plate-like fillers are more preferable, from the viewpoint that the coefficient of thermal expansion (CTE) can be adjusted even in a small amount and compatibility with flexibility is possible.
The average particle size of the filler is preferably 0.05 μm to 20 μm, preferably 0.1 μm to 15 μm, more preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 7 μm. When the average particle size of the filler is 0.05 μm or more, the filler has good dispersibility and can effectively impart the above functions. If the average particle size of the filler is 0.1 μm or more, the effect of the aspect ratio of the non-spherical filler becomes effective. If the average particle diameter of the filler is 20 μm or less, the inclusion of coarse particles is reduced, and the thickness of the base film can be reduced. If the average particle diameter of the filler is 10 µm or less, the surface roughness of the substrate film can be reduced, and a smooth layer made of the resin composition can be easily formed.
In addition, the aspect ratio (average major axis length/average minor axis length), which means the planar direction and thickness of the non-spherical filler, is 5 or more and 500 or less, preferably 10 or more and 500 or less, from the viewpoint of the coefficient of thermal expansion (CTE). is preferably
If the aspect ratio is 5 or more, it is easy to make the CTE sufficiently small.
The larger the aspect ratio, the easier it is to adjust the CTE.

[Measurement of average particle size and aspect ratio]
The average particle size and aspect ratio of the inorganic filler can be obtained by observing, for example, using a scanning electron microscope (SEM) or a transmission electron microscope (TEM) and averaging measured values at three or more locations. Regarding the average particle size and aspect ratio of the inorganic filler present in the film (layer), for example, after embedding the film in epoxy resin, ion milling of the cross section of the film is performed using an ion milling device for cross-sectional observation. A sample is prepared, a cross section of the obtained sample is observed using a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and the average of measured values at three or more points can be obtained.
In addition, the average particle size of the organic filler is obtained by observing the cut surface of the base film with an electron microscope and measuring the maximum diameter of at least 10 particles. It can be obtained as the average dispersed particle diameter when dispersed in the inside.

The content of the filler in the base film is preferably 1% by volume or more and 30% by volume or less, more preferably 3% by volume or more and 25% by volume or less.

The mass ratio of Si element to carbon atoms (Si/C) on the surface of the substrate film is preferably 3% or more as measured by an electron probe microanalyzer (EPMA). For example, if the base film contains an inorganic filler, and if the inorganic filler protrudes from the surface of the base film, the silane coupling agent acts on the inorganic filler protruding from the surface, so a strong Adhesion is developed. Therefore, it is preferable to obtain a result that the mass ratio of Si element to carbon atoms is 3% or more on the surface of the substrate film by measurement with an electron probe microanalyzer (EPMA).

<<Other Ingredients>>
In the present invention, the base film may optionally contain known additives as required. Examples of additives include antioxidants, light stabilizers, ultraviolet absorbers, crystal nucleating agents, plasticizers, filler dispersants, and the like.

<<Characteristics of base film>>
The film thickness of the substrate film is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 250 μm.

The surface roughness (Rz) of the base film is not particularly limited and can be appropriately selected according to the purpose. Considering various conditions such as the method, the surface roughness (Rz) of the base film is 1 μm or more. On the other hand, in order to keep the surface roughness (Rz) of the resin composition layer formed on the base film within a desired range, the surface roughness (Rz) of the base film is preferably 10 μm or less. preferable. That is, the surface roughness (Rz) of the substrate film is preferably 1 μm or more and 10 μm or less, more preferably 1 μm or more and 4 μm or less. If it is 4 μm or less, the surface roughness of the layer made of the resin composition can be easily reduced, and if it is 1 μm or more, the area where the inorganic filler is exposed on the substrate film surface increases, and it strongly acts with the silane coupling agent. Thus, the interlayer adhesion between the base film and the layer made of the resin composition can be ensured.
In this specification, the surface roughness (Rz) (surface roughness (Rz) of the base film, the surface roughness (Rz) of the layer composed of a resin composition containing a silane coupling agent described later, and the surface roughness of the metal film roughness (including Rz)) refers to the ten-point average roughness of the film surface. Ten-point average roughness Rz indicates Rz JIS described in JIS B 0601: 2013 (ISO 4287: 1997 Amd.1: 2009) Annex JA, and JIS B 0601: 2013 Annex JA JA. It can be obtained based on the method described in 2 a).

[Measurement of ten-point average roughness Rz]
The ten-point average roughness Rz (μm) of the surface of the sheet is obtained by measuring the roughness curve of the test piece using a laser microscope, and from this roughness curve, JIS B 0601: 2013 (ISO 4287: 1997 Amd.1: 2009) Annex JA JA. Based on the method described in 2 a), each 10 samples are measured and their average value is obtained.

The relative dielectric constant and dielectric loss tangent of the base film are not particularly limited and can be appropriately selected according to the purpose. , the dielectric loss tangent is preferably 0.005 or less.

[Relative permittivity and dielectric loss tangent]
The relative dielectric constant and dielectric loss tangent of the base film were determined by the open resonator method using a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry-Perot DPS-03 (manufactured by KEYCOM) at a temperature of 23°C. , humidity of 50% RH, and frequency of 28 GHz.

The coefficient of thermal expansion (CTE) of the base film is not particularly limited, and can be appropriately selected according to the purpose. is preferably 50 ppm or less, for example.
The coefficient of thermal expansion was measured in a tensile mode using a thermomechanical analyzer (product name: SII//SS7100 manufactured by Hitachi High-Tech Science) under a load of 50 mN and a temperature increase rate of 5°C/min. The temperature is increased from 25°C to 250°C at a rate of 5°C/min, the temperature change in dimensions is measured, and the coefficient of linear expansion is obtained from the slope in the range from 25°C to 125°C. ,It can be carried out.

The surface of the base film may be surface-treated by corona treatment, plasma treatment, or ultraviolet treatment for the reason of improving adhesion with the layer made of the resin composition.

<Layer made of resin composition>
The layer made of the resin composition is formed, for example, by forming a film of the resin composition and curing the coating film made of the resin composition.
The surface roughness (Rz) of the layer made of the resin composition is 1 μm or less.
The surface roughness (Rz) of the layer made of the resin composition is preferably 0.01 μm or more and 1 μm or less, more preferably 0.01 μm or more and 0.5 μm or less, and more preferably 0.01 μm or more and 0.01 μm or more. 0.25 μm or less is preferred. The method for measuring the surface roughness (Rz) is as described in the section <<characteristics of base film>> above.
When the surface roughness (Rz) of the layer made of the resin composition is 0.01 μm or more, it is possible to obtain a metal-clad laminate excellent in adhesion of the metal film. When the layer made of the resin composition has a surface roughness (Rz) of 1 μm or less, the metal-clad laminate can be used as a printed wiring board used for 6 GHz band communications in fifth-generation mobile communication systems. When the layer made of the resin composition has a surface roughness (Rz) of 0.5 μm or less, the metal-clad laminate can be used as a printed wiring board used for 28 GHz band communications in fifth-generation mobile communication systems. When the surface roughness (Rz) of the layer made of the resin composition is 0.25 μm or less, the metal-clad laminate can be used for printed wiring boards used for communications in the millimeter wave band of 30 GHz or higher.
The resin composition is preferably made of a thermosetting resin.
Examples of thermosetting resins include phenol resins, epoxy resins, urea resins, melamine resins, unsaturated polyester resins, polyurethane resins, polyimide resins, silicone resins, and maleimide resins. From the viewpoint of dielectric properties, it is preferably at least one of epoxy resin, polyimide resin, and maleimide resin.
In the present invention, the resin composition contains a silane coupling agent.

<<epoxy resin>>
Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, or hydrogenated versions thereof; diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, p-hydroxybenzoic acid Glycidyl ester epoxy resins such as glycidyl ester, diglycidyl tetrahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, and triglycidyl trimellitate; ethylene glycol diglycidyl ether, propylene glycol Diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, sorbitol glycidyl ether-based epoxy resins such as polyglycidyl ether of polyglycerol and polyglycidyl ether of polyglycerol; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyldiaminodiphenylmethane; linear aliphatics such as epoxidized polybutadiene and epoxidized soybean oil Examples include, but are not limited to, epoxy resins and the like. Novolac epoxy resins such as xylene structure-containing novolac epoxy resins, naphthol novolac epoxy resins, phenol novolak epoxy resins, o-cresol novolak epoxy resins, and bisphenol A novolak epoxy resins can also be used.

Furthermore, examples of epoxy resins include brominated bisphenol A type epoxy resins, phosphorus-containing epoxy resins, fluorine-containing epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, naphthalene skeleton-containing epoxy resins, anthracene-type epoxy resins, and tertiary-butylcatechol-type epoxy resins. Resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, biphenyl type epoxy resin, bisphenol S type epoxy resin, etc. can be used. These epoxy resins may be used alone or in combination of two or more.

<<Maleimide Resin>>
Examples of maleimide resins include 1-methyl-2,4-bismaleimidobenzene, N,N'-m-phenylenebismaleimide, N,N'-p-phenylenebismaleimide, and N,N'-m-toluylene. bismaleimide, N,N'-4,4-biphenylenebismaleimide, N,N'-4,4-(3,3'-dimethyl-biphenylene)bismaleimide, N,N'-4,4-(3, 3′-dimethyldiphenylmethane)bismaleimide, N,N′-4,4-(3,3′-diethyldiphenylmethane)bismaleimide, N,N′-4,4-diphenylmethanebismaleimide, N,N′-4, 4-diphenylpropanebismaleimide, N,N'-4,4-diphenyletherbismaleimide, N,N'-3,3-diphenylsulfonebismaleimide and the like.
Further examples include modified maleimide obtained by modifying the above maleimide resin with a compound having a primary amine, and polymers obtained by chain extension with amine-modified products such as dimer acid and trimer acid and maleic anhydride and pyromellitic acid.
A commercially available compound can also be used as the maleimide resin. can be preferably used.

In the present invention, the maleimide resin contained in the resin composition preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 5,000 to 40,000. When the weight-average molecular weight is 5,000 or more, the leveling property of the resin composition layer during film formation is improved, and the surface roughness of the resin composition layer can be reduced. When the weight-average molecular weight is 100,000 or less, it is possible to impart appropriate flexibility to the cured product of the resin composition and exhibit excellent adhesiveness. Also, the heat resistance is enhanced. If the weight-average molecular weight is 40,000 or less, the solubility of the maleimide resin and other additives and the dispersibility of fillers are improved, and both performance improvement and surface roughness reduction can be achieved. .

<<Silane coupling agent>>
By including a silane coupling agent in the resin composition, as shown in the following examples, the adhesion between the layer made of the resin composition and the substrate film, and the layer made of the resin composition and the metal film described later ( adhesion) can be improved, and a metal-clad laminate having good adhesion can be produced.

The silane coupling agent used in the present invention is not particularly limited as long as it can produce a metal-clad laminate with good adhesion, and can be appropriately selected according to the purpose. Examples include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycid xypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3- aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, hexamethyldisilazane, 3-(2-aminoethylaminopropyl)dimethoxymethylsilane, 3-(2-aminoethylaminopropyl ) trimethoxysilane, 2-(2-aminoethylthioethyl)diethoxymethylsilane, 2-(2-aminoethylthioethyl)triethoxysilane, 3-[2-(2-aminoethylaminoethylamino)propyl] Trimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3- Aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis( triethoxysilylpropyl)tetrasulfide, imidazolylalkyl-trialkoxysilane, diphenyldimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, trifluoropropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyl triethoxysilane, dimethyltriethoxysilane, phenyltriethoxysilane, and the like.

In the present invention, the silane coupling agent is an imidazole skeleton, a triazole skeleton, a triazine skeleton, an olefin skeleton, a mercapto group, a maleic anhydride skeleton, an imide skeleton, or a silane coupling agent containing an amino functional group. is preferred. When a silane coupling agent having any of these groups is contained, adhesion is improved even with a small amount of addition. When a maleimide resin is contained in the resin composition, the silane coupling agent having these groups reacts with the maleimide resin or acts as a reaction accelerator to improve heat resistance. can be done.
Moreover, in the present invention, the silane coupling agent is preferably in a liquid state at 100°C. When the silane coupling agent is in a liquid state at 100° C., when a metal film is formed on the layer made of the resin composition by sputtering, the temperature of the surface of the layer made of the resin composition rises due to the collision of the metal particles. At a surface temperature of about 100° C., which is often observed in the sputtering method, the alkoxysilane groups and the above-described functional groups are more likely to be oriented at the interface with the metal film, improving adhesion.
Furthermore, in the present invention, the silane coupling agent is preferably a silane coupling agent having a butadiene skeleton. When the silane coupling agent has a butadiene skeleton and the maleimide resin is contained in the resin composition, the maleimide resin and the silane coupling agent having the butadiene skeleton can be crosslinked. By improving the crosslinking density, it is possible to form a layer made of a resin composition with improved heat resistance, adhesion strength, and flexibility.
As the silane coupling agent having a butadiene skeleton, Shin-Etsu Chemical Co., Ltd. "X-12-1281A", "X-12-1281A-ES", "X-12-1287A", "X-12-1267B" ”, “X-12-1267B-ES”.

The content of the silane coupling agent in the resin composition is preferably 0.1 to 20 parts by mass of the silane coupling agent per 100 parts by mass of the resin composition. If the content of the silane coupling agent is at least the above lower limit, the adhesion is improved. If the content of the silane coupling agent exceeds the above upper limit, the silane coupling agent that has not reacted with the maleimide resin will bleed out, or the compatibility will deteriorate and the surface roughness will increase.

In addition, the layer made of the resin composition can also contain other components such as fillers and various additives.

<<Filler>>
The layer made of the resin composition may contain a filler for improving heat resistance, controlling fluidity, and the like. The type of filler is not particularly limited and can be appropriately selected depending on the purpose. can be used.
The average particle diameter of the filler contained in the layer made of the resin composition is preferably 0.01 μm to 20 μm, preferably 0.01 μm to 10 μm, more preferably 0.01 to 5 μm.

The content of the filler in the layer made of the resin composition is preferably 0.1% by volume or more and 50% by volume or less, more preferably 1% by volume or more and 25% by volume or less.
Since the layer made of the resin composition is required to have a higher surface smoothness than the base film, it is preferable that the average particle diameter of the filler used is smaller than that of the base film and the content thereof is small.

<<Other Ingredients>>
In addition to the above-described thermosetting resin, silane coupling agent, and filler, the resin composition may contain a tackifier, a flame retardant, a curing agent, a curing accelerator, a heat antioxidant, a leveling agent, an antifoaming agent, and a pigment. , a solvent, etc. can be contained to such an extent that the functions of the resin composition are not affected. Among them, it is preferable to contain oxazine as a curing agent.

<<<Oxazine>>
The resin composition preferably contains an oxazine, more specifically a benzoxazine resin. By reacting with the resin in the resin composition, particularly with the maleimide resin when the resin composition contains a maleimide resin, and increasing the crosslink density of the resin composition, high adhesion to the adherend, This is because the heat resistance of the cured product of the resin composition can be exhibited.
Benzoxazine resins include, for example, 6,6-(1-methylethylidene)bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine), 6,6-(1-methylethylidene) Examples thereof include bis(3,4-dihydro-3-methyl-2H-1,3-benzoxazine) and the like, and two or more of them may be combined. A phenyl group, a methyl group, a cyclohexyl group, or the like may be bonded to the nitrogen of the oxazine ring. Further, specific examples of benzoxazine resins include "Benzoxazine Fa", "Benzoxazine Pd" and "Benzoxazine ALP-d" manufactured by Shikoku Kasei Co., Ltd., Tohoku Kako Co., Ltd. ``CR-276'' and ``BZ-LB-MDA'' manufactured by K.K.

The thickness of the layer made of the resin composition is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, and particularly preferably 3 μm or more. If the film thickness of the layer made of the resin composition is at least the above lower limit, sufficient uniformity for smoothing the surface of the substrate film can be maintained. The thickness of the layer made of the resin composition is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 20 μm or less, and particularly preferably 10 μm or less. If the thickness of the layer made of the resin composition is 100 μm or less, the coating of the layer made of the resin composition is easy. It is possible, and if the film thickness of the layer made of the resin composition is 20 μm or less, the concentration of stress on the layer made of the resin composition can be reduced, and the adhesion can be improved. Furthermore, when the film thickness of the layer made of the resin composition is 10 μm or less, a laminate obtained by laminating a resin film containing polyetheretherketone as a base film exhibits the properties of polyetheretherketone having a low CTE in the thickness direction. Do not harm.
In addition, the film thickness of the layer made of the resin composition is such that the layer made of the resin composition smoothes the surface of the substrate film and, in turn, smoothes the surface of the metal film, thereby obtaining a desired reduction in electrical signal loss. It is preferably 0.7 times or more the surface roughness (Rz) μm of the substrate film, more preferably 1 time or more the surface roughness (Rz) μm of the substrate film. More preferably, the surface roughness (Rz) of the material film is at least 1.2 times the μm value.

The dielectric constant and dielectric loss tangent of the layer made of the resin composition are not particularly limited and can be appropriately selected according to the purpose. 0.5 or less and the dielectric loss tangent is preferably 0.004 or less.
The method for measuring the dielectric constant and the dielectric loss tangent is as described in the section <<characteristics of the base film>> of the base film.

The surface of the layer made of the resin composition may be surface-treated by corona treatment, plasma treatment, or ultraviolet treatment for the reason of improving adhesion with the metal film.

<<Method for producing layer made of resin composition>>
The layer made of the resin composition can be formed by forming a film of the resin composition and curing the coating film made of the resin composition.
The resin composition can be produced by mixing an epoxy resin, polyimide resin, maleimide resin, or the like, a silane coupling agent, and other components. The mixing method is not particularly limited as long as the resin composition is uniform. Since the resin composition is preferably used in the form of a solution or dispersion, a solvent is also usually used.
Examples of solvents include alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol. ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, esters such as 3-methoxybutyl acetate; aliphatic hydrocarbons such as hexane, heptane, cyclohexane and methylcyclohexane; These solvents may be used alone or in combination of two or more.
When the resin composition is a solvent-containing solution or dispersion (resin varnish), coating on the substrate film and formation of the coating film can be performed smoothly, and the desired thickness and surface roughness of the resin composition A coating film consisting of a substance can be easily obtained.
When the resin composition contains a solvent, the solid content concentration is preferably in the range of 3 to 80% by mass, more preferably 10 to 50% by mass, from the viewpoint of workability including formation of a coating film. When the solid content concentration is 80% by mass or less, the viscosity of the solution is moderate, and it is easy to apply uniformly.
As a more specific embodiment of the method for producing a coating film, a resin varnish containing the above resin composition, a silane coupling agent, and a solvent is applied to the surface of a base film to form a resin varnish layer. A B-stage coating film can be formed by removing the solvent from the resin varnish layer. Here, the coating film is in a B-stage state means that the resin composition is in an uncured state or a semi-cured state in which a part of the resin composition has begun to be cured, and a state in which the resin composition is further cured by heating or the like. say.
Here, the method for applying the resin varnish on the substrate film is not particularly limited and can be appropriately selected according to the purpose. A blade coating method, a doctor roll method, a doctor blade method, a curtain coating method, a slit coating method, a screen printing method, an inkjet method, a dispensing method, and the like can be mentioned.
The B-stage coating film can be further subjected to heating or the like to form a cured coating film, that is, a layer made of the resin composition.

<Laminate characteristics>
The laminate has a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.005 or less under the condition of a frequency of 28 GHz.
The method for measuring the dielectric constant and the dielectric loss tangent is as described in the section <<characteristics of the base film>> of the base film.

(Metal clad laminate)
The metal-clad laminate of the present invention is obtained by laminating a metal film on the layer made of the resin composition of the laminate of the present invention.
In a metal-clad laminate, a layer made of a resin composition and a metal film are laminated in this order on a substrate film.
The metal film is preferably a metal film formed by at least one of plating, sputtering, and vapor deposition.
Further, in the metal-clad laminate of the present invention, a layer comprising a resin composition and a metal film may be laminated on both sides of the substrate film.
In this case, the metal-clad laminate is laminated in the order of the metal film, the layer made of the resin composition, the substrate film, the layer made of the resin composition, and the metal film.

FIG. 1 is a cross-sectional view showing an example of the configuration of the metal-clad laminate of the present invention.
The metal-clad laminate 1 has a base film 2, a layer 3 made of a resin composition, and a metal film 4, which are laminated in this order.
FIG. 2 shows another example of the structure of the metal-clad laminate of the present invention.
The metal-clad laminate 1 of the present invention shown in FIG. 2 comprises a metal film 4a, a resin composition layer 3a, a substrate film 2, a resin composition layer 3b, and a metal film 4b, which are laminated in this order.

<Metal film>
The metal film is formed by at least one of plating, sputtering, and vapor deposition.
When a metal film is formed by at least one of plating, sputtering, and vapor deposition on a layer made of a resin composition having a surface roughness (Rz) of 1 μm or less, a metal film with a smooth surface is formed. can do.
In addition, the metal films formed by these forming methods enable formation of fine pitch circuit patterns and high-precision fine circuit formation.
The plating method and the sputtering method may be used separately or in combination. For example, when used together, a copper film can be formed by electrolytic copper plating after spreading a thin copper film by sputtering.

The metal constituting the metal film is not particularly limited and can be appropriately selected depending on the intended purpose. An alloy or the like containing one or more selected types may be mentioned. Among them, copper and alloys containing copper are preferable from the viewpoint of shielding properties and economy.

As mentioned above, the method of forming the metal film includes at least one of plating, sputtering, and vapor deposition. More specifically, for example, vapor deposition films formed by physical vapor deposition (vacuum vapor deposition, sputtering, ion beam vapor deposition, electron beam vapor deposition, etc.) or chemical vapor deposition, plated films formed by plating, and the like can be mentioned. Among them, a vacuum deposition film or a sputtering film formed by a vacuum deposition method (vacuum deposition method, sputtering method, etc.) or a plated film formed by an electrolytic plating method is preferable from the viewpoint of excellent electrical conductivity in the plane direction. A sputtered film is more preferable from the viewpoint that adhesion can be improved by an anchor effect and an increase in surface temperature.

The film thickness of the metal film is preferably 0.05 μm to 10 μm, more preferably 0.1 to 10 μm, from the viewpoint of ensuring sufficient electrical signal transmission characteristics and enabling a fine pitch of the circuit pattern. and preferably 0.5 to 10 μm.
The surface roughness (Rz) of the metal film on the surface not in contact with the layer made of the resin composition is not particularly limited and can be appropriately selected according to the purpose. to 0.5 μm or less.

<Effect of metal-clad laminate>
It is difficult to smooth the surface of the base film because the base film contains a filler or for manufacturing reasons of the base film. By forming the film, a smooth metal film can be laminated, and transmission loss can be reduced. Further, since the layer made of the resin composition is provided, the metal-clad laminate has excellent adhesion between the base film and the metal film even when a smooth metal film is used. Furthermore, in the present invention, since the layer made of the resin composition contains a silane coupling agent, the adhesion between the base film and the metal film can be further enhanced.
In addition, by forming the metal film formed on the laminate of the present invention by at least one of plating, sputtering, and vapor deposition, it is possible to form a fine-pitched circuit pattern and to form a highly accurate and fine circuit. It can be a metal-clad laminate that can be used.

<Film thickness of metal-clad laminate>
The film thickness of the metal-clad laminate is not particularly limited and can be appropriately selected according to the purpose. is more preferred. When the film thickness of the metal-clad laminate is at least the lower limit value of the above range, the handleability is excellent and the strength can be ensured. Moreover, when the thickness is equal to or less than the upper limit of the above range, lightness, thinness, shortness and flexibility can be imparted.

<Method for producing metal-clad laminate>
A layer made of a resin composition is formed on the base film.
A metal film is formed on the surface of the layer made of the resin composition opposite to the base film.
A more specific method for forming a layer made of a resin composition is as described in the section <<Method for producing a layer made of a resin composition>>, and includes a resin composition, a silane coupling agent, A coating film can be formed by applying a resin varnish containing a solvent to the surface of a substrate film to form a resin varnish layer, and then removing the solvent from the resin varnish layer. The coating film can be further cured by heating or the like to form a layer composed of the resin composition.
The method for applying the resin varnish is not particularly limited and can be appropriately selected depending on the intended purpose. A doctor blade method, a curtain coating method, a slit coating method, a screen printing method, an inkjet method, a dispensing method, and the like can be mentioned.
Examples of the method for forming the metal film include a method using a vacuum film forming method (vacuum deposition, sputtering), a method using an electroplating method, and the like.
From the point that a metal film having a desired film thickness and surface shape can be formed, a method of forming a deposited film by vacuum deposition, a method of forming a plated film by electrolytic plating, a method of forming a sputtered film by sputtering, or sputtering Electroplating can be performed later to form a metal film using both sputtering and plating.

When the metal-clad laminate of the present invention is a metal-clad laminate in which a layer made of a resin composition and a metal film are provided on both sides of a base film as shown in FIG. A layer made of a resin composition and a metal film are formed on one surface by the method described above, and then a layer made of a resin composition and a metal film are formed on the other surface of the base film by the same method. A film can be formed. Alternatively, a method may be used in which layers made of the resin composition are formed together on both sides of the base film, and then metal films disposed on the layer made of the resin composition are also formed together on both sides. .

When the base film and/or the layer consisting of the resin composition uses a base film or a layer consisting of the resin composition that has been surface-treated by corona treatment, plasma treatment, ultraviolet treatment, or the like, for example, the base film is prepared, the surface of the prepared base film is surface-treated, and a layer composed of the resin composition is formed on the surface-treated base film by the method described above. Moreover, after forming the layer made of the resin composition, the surface of the layer made of the resin composition may be surface-treated, and then the metal film may be formed by the method described above.

In addition to producing the metal-clad laminate using the laminate of the present invention, the laminate of the present invention can be used to produce the following printed wiring boards, shield films, and printed wiring boards with shield films. can be made.

(Printed wiring board)
A preferred embodiment of the laminate according to the present invention is a printed wiring board in which copper wiring is formed in the layer of the resin composition in the laminate according to the present invention.
A printed wiring board is obtained by forming an electronic circuit on the copper-clad laminate.
A printed wiring board is formed by laminating a substrate film and copper wiring using the laminate, and is composed of a substrate film, a layer made of a resin composition, and copper wiring in this order. The layer made of the resin composition and the copper wiring may be formed on both sides of the substrate film.
For example, a printed wiring board is manufactured by using a hot press or the like to attach a coverlay film to a surface having a wiring portion via an adhesive layer.
Since the printed wiring board according to the present invention uses the low-dielectric resin composition of the present invention, it enables high-speed transmission of electronic devices and has excellent adhesion stability.
As a method for producing a printed wiring board according to the present invention, for example, the adhesive layer of the laminate is brought into contact with the copper wiring, heat lamination is performed at 80 ° C. to 200 ° C., and the resin composition is removed by after-curing. There is a method to harden the different layers. The after-cure conditions can be, for example, 100° C. to 200° C. and 30 minutes to 4 hours. The shape of the copper wiring is not particularly limited, and any suitable shape may be selected as desired.

(shield film)
A preferred embodiment of the laminate according to the present invention is a shield film.
A shield film is a film for shielding various electronic devices in order to cut electromagnetic noise that affects various electronic devices such as computers, mobile phones, and analytical instruments and causes malfunctions. Also called electromagnetic wave shielding film.
The electromagnetic wave shielding film is formed by laminating an adhesive layer, a metal layer, and the laminate of the present invention, for example. The layer made of the resin composition of the laminate of the present invention is in contact with the metal layer.
Since the shielding film according to the present invention uses the low-dielectric resin composition of the present invention, high-speed transmission of electronic devices is possible, and the adhesive stability with electronic devices is also excellent.

(Printed wiring board with shield film)
A preferred embodiment of the laminate according to the present invention is a printed wiring board with a shield film.
A printed wiring board with a shielding film is a printed wiring board having a printed circuit on at least one side of a substrate, and the electromagnetic wave shielding film is attached on the printed wiring board.
A printed wiring board with a shield film includes, for example, a printed wiring board, an insulating film adjacent to the surface of the printed wiring board on which the printed circuit is provided, and the electromagnetic wave shielding film.
Since the printed wiring board with a shielding film according to the present invention uses the low dielectric resin composition of the present invention, it enables high-speed transmission of electronic devices and has excellent adhesion stability.

Although the present invention will be described in more detail with examples below, the scope of the present invention is not limited to these examples. In the following, parts and % are based on mass unless otherwise specified.

(Production example 1 of base material)
100 parts by mass of polyether ether ketone (PEEK) resin (381G: manufactured by Victrex) and 45 parts by mass of synthetic mica (MK-100PGDS: manufactured by Katakura Agricorp) are mixed, and the mixture is kneaded with a twin-screw kneader. It was extruded and made into pellets. The synthetic mica used had an average particle size of 4.4 μm and an aspect ratio of 41.9.
The obtained pellets were put into a single-screw extruder with a T-die having a width of 900 mm, melt-kneaded, and continuously extruded from the T-die to obtain a PEEK substrate film having a thickness of 100 μm (Substrate A-1 ).
When the surface roughness (Rz) of this PEEK base film was measured using a laser microscope, it was Rz: 3.63 μm.
When the CTE in the thickness direction of this PEEK base film was measured, it was 48 ppm/°C.
The mass ratio of Si element to carbon atoms (Si/C) on the surface of this PEEK base film was measured by an electron probe microanalyzer (EPMA) and found to be 12.91%.
The measurement results of the substrate A-1 obtained in Production Example 1 are shown in Table 1 below.

(Base material production examples 2-3)
Substrates A-2 and A-3 were produced by changing the conditions of the substrate A-1 of Production Example 1 as shown in Table 1 below and adjusting the production conditions. The measurement results of the substrates A-2 and A-3 obtained in Production Examples 2 and 3 are shown in Table 1 below.

 

 

(Each component used in the resin composition)
<Bismaleimide resin>
A trade name “SLK-3000-T50” manufactured by Shin-Etsu Chemical Co., Ltd. was used. Solid content 50%, solvent: toluene, number average molecular weight 7,725, weight average molecular weight 12,545, softening point 40°C.
<Bismaleimide resin>
A trade name “SLK-1500-T80” manufactured by Shin-Etsu Chemical Co., Ltd. was used. Solid content 80%, solvent: toluene, number average molecular weight 3,257, weight average molecular weight 5,040, softening point 45°C.
<Silane coupling agent>
The trade name "X-12-1281A" manufactured by Shin-Etsu Chemical Co., Ltd. was used. It is a silane coupling agent having a styrene-butadiene polymer structure. It is in a liquid state at room temperature.
<Silane coupling agent>
The trade name "VD-5" manufactured by Shikoku Kasei Kogyo Co., Ltd. was used. It is a silane coupling agent having a triazine skeleton. It has a melting point of 85°C.
<Silane coupling agent>
The trade name "2MUSIZ" manufactured by Shikoku Kasei Kogyo Co., Ltd. was used. It is a silane coupling agent having an imidazole skeleton. It is in a liquid state at room temperature.
<Silane coupling agent>
The trade name "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd. was used. It is a silane coupling agent having an epoxy skeleton. It is in a liquid state at room temperature.
<Curing agent>
The trade name "PERHEXA 25O" manufactured by NOF Corporation was used. 50% solids.
<Curing agent: benzoxazine resin>
A product name “ALP-d” (liquid) manufactured by Shikoku Kasei Co., Ltd. was used.

(Formulation example 1 of resin composition)
Bismaleimide resin (SLK-3000-T50: Shin-Etsu Chemical Co., Ltd.), bismaleimide resin (SLK-1500-T80: Shin-Etsu Chemical Co., Ltd.) silane coupling agent (X-12-1281A: Shin-Etsu Chemical Co., Ltd.), curing agent (Perhexa 25O (manufactured by NOF Corporation), toluene, and methyl isobutyl ketone (MIBK) were mixed according to the composition shown in Table 2 below to obtain a coating solution (coating solution) B-1.
Table 3 below shows the solid content ratio in the coated layer after drying the solvent from the coating film of the resin composition.

(Resin Composition Formulation Examples 2 to 7)
The conditions of the resin composition B-1 of Formulation Example 1 were changed as shown in Table 2 below to prepare resin compositions B-2 to B-7. The measurement results of the resin compositions B-2 to B-7 obtained in Formulation Examples 2 to 7 are shown in Table 2 below.
For Formulation Examples 2 to 7, Table 3 below shows the solid content ratio in the coated layer after drying the solvent from the coating film of the resin composition.

 

 

 

 

(Example 1)
The surface of the PEEK base film of Production Example 1 was subjected to corona treatment, and the coating solution of Formulation Example 1 was applied to a film thickness of 5 μm on the surface-treated PEEK base film. was dried.
Curing was performed at a temperature of 80° C. for 72 hours to cure the coating film.
At this stage, the surface roughness (Rz) of the surface of the layer (coating film) made of the resin composition is measured, and the laminate having the PEEK base film and the layer made of the resin composition has a frequency of 28 GHz. We measured the relative permittivity and dielectric loss tangent of

[Relative permittivity and dielectric loss tangent]
The relative dielectric constant and dielectric loss tangent of the adhesive layer were determined by the open resonator method using a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry-Perot DPS-03 (manufactured by KEYCOM) at a temperature of 23°C. , and a frequency of 28 GHz.

(Adhesion test)
A copper film (thickness: 0.1 μm) was formed by magnetron sputtering on the resin composition layer of the laminate having the PEEK base film and the resin composition layer.
The adhesion force is measured for the metal-clad laminate (copper-clad laminate) of Example 1 thus obtained. However, since the thickness of the copper film is as thin as 0.1 μm, if the copper film breaks when measuring the adhesion, the adhesion between the copper film and the PEEK substrate cannot be measured. An adhesive layer and a copper foil were laminated on the film to prevent tearing of the copper film, and then the adhesion between the copper film and the PEEK substrate was evaluated.
Therefore, a laminate (I) for adhesion measurement is produced by laminating an adhesive layer for reinforcing a copper film and a copper foil on the metal-clad laminate (copper-clad laminate) of Example 1 in the following manner. bottom.
-Laminate for adhesion measurement (I)-
A coating solution of an adhesive composition having the following composition was further coated on the copper film so that the film thickness after drying was 25 μm, and then dried to form an adhesive layer (i).
・ Composition of adhesive composition: 75 parts by mass of amine-modified styrene-ethylenebutylene-styrene copolymer (manufactured by Asahi Kasei Co., Ltd. “Tuftec MP10”), bismaleimide resin (manufactured by Shin-Etsu Chemical Co., Ltd. “SKL-3000-T50”) 25 Part by mass, 3 parts by mass of organic peroxide ("Perbutyl E" manufactured by NOF Corporation).
Next, the electrolytic copper foil was laminated so that the glossy surface of the electrolytic copper foil was in contact with the adhesive layer (i). Thereafter, heat lamination was performed at 120° C., and after-curing was performed at 150° C. for 60 minutes to cure the adhesive layer (i) and obtain a laminate (I) for adhesion measurement.
Electrolytic copper foil: "TQ-M7-VSP" manufactured by Mitsui Kinzoku Mining (thickness: 12 µm, glossy surface: Rz: 1.27 µm, glossy surface: Ra: 0.197 µm, glossy surface: Rsm: 12.95 µm) was used.
For the laminate for adhesion measurement (I) obtained by laminating an adhesive layer for reinforcing a copper film and a copper foil on the metal-clad laminate (copper-clad laminate) of Example 1 obtained as described above Then, the adhesion force was measured as follows.
In addition, after storing the laminate (I) for adhesion measurement of Example 1 at a temperature of 150° C. for one week, the adhesion was measured to evaluate the degree of reduction in adhesion due to heat resistance.

[Adhesion (N/cm)]
Adhesion was measured by cutting the laminate (I) for adhesion measurement into a test specimen with a width of 25 mm, and measuring the peel speed of 0.3 m / min in accordance with JIS Z0237: 2009 (adhesive tape/adhesive sheet test method). Measure the peel strength when peeling off a copper film (an adhesive layer and a copper foil are laminated on the copper film) from a base film with a layer made of a resin composition fixed to a support at a peel angle of 180 °. By doing so, the adhesion strength was measured.

Table 4 shows the measurement results of the laminate used in Example 1 and the evaluation results of the adhesion test of the adhesion measurement laminate (I) including the copper-clad laminate.

(Examples 2 to 8, Comparative Example 1)
In Example 1, Examples 2 to 8, and Comparative A copper-clad laminate of Example 1 and a laminate (I) for adhesion measurement containing the copper-clad laminate were produced.

The same evaluation as in Example 1 was performed on the laminates (I) for adhesion measurement produced in Examples 2 to 8 and Comparative Example 1.
Table 4 shows the measurement results of the laminates used in Examples 2 to 8 and Comparative Example 1, and the adhesion test evaluation results of the adhesion measurement laminate (I).

 

 

The metal-clad laminates of the present invention produced in Examples have a smooth metal film surface, so that they are metal-clad laminates capable of reducing transmission loss. Since the layer made of the resin composition is provided, the adhesiveness between the base film and the metal film is excellent even if a smooth metal film is used.
In particular, in the present invention, since the layer made of the resin composition contains a silane coupling agent, the adhesion between the base film and the metal film can be further enhanced.

The metal-clad laminate of the present invention can be suitably used for manufacturing FPC-related products for electronic devices such as smart phones, mobile phones, optical modules, digital cameras, game machines, notebook computers, and medical instruments.

1 Metal-clad laminate 2 Base film 3, 3a, 3b Layer made of resin composition 4, 4a, 4b Metal film

Claims (21)

A laminate having a base film and a layer made of a resin composition containing a silane coupling agent,
The surface roughness (Rz) of the layer made of the resin composition is 1 μm or less,
A laminate having a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.005 or less under the condition of a frequency of 28 GHz. The laminate according to claim 1, wherein the surface roughness (Rz) is 0.5 µm or less. The laminate according to claim 1, wherein the silane coupling agent is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the resin composition. The silane coupling agent is a silane coupling agent containing any one of functional groups selected from an imidazole skeleton, a triazole skeleton, a triazine skeleton, an olefin skeleton, a mercapto group, a maleic anhydride skeleton, an imide skeleton, and an amino group. 2. The laminate according to 1. The laminate according to claim 1, wherein the silane coupling agent has a melting point of 100°C or less. The laminate according to claim 1, wherein the silane coupling agent is a silane coupling agent having a butadiene skeleton. The laminate according to claim 1, wherein the resin composition further contains a maleimide resin. The laminate according to claim 7, wherein the maleimide resin has a weight average molecular weight of 5,000 to 100,000. The laminate according to claim 8, wherein the maleimide resin has a weight average molecular weight of 5,000 to 40,000. The laminate according to claim 1, wherein the resin composition further contains oxazine. The laminate according to claim 1, wherein the layer made of the resin composition is a cured film obtained by curing a coating film made of the resin composition. The laminate according to claim 1, wherein the layer made of the resin composition has a thickness of 20 µm or less. The laminate according to claim 1, wherein the base film has a surface roughness (Rz) of 1 to 4 μm. The laminate according to claim 1, wherein the base film contains a filler. The laminate according to claim 14, wherein the filler has an average particle size of 20 µm or less. The laminate according to claim 14, wherein the filler contains at least one of mica, talc, boron nitride (BN) and silica. The laminate according to claim 14, wherein the filler has a plate-like shape. The laminate according to claim 1, wherein the mass ratio (Si/C) of Si element to carbon atoms on the surface of the base film is 3% or more as measured by an electron probe microanalyzer (EPMA). A metal-clad laminate obtained by laminating a metal film on a layer made of the resin composition of the laminate according to any one of claims 1 to 18,
A metal-clad laminate, wherein the metal film is a metal film formed by at least one of plating, sputtering, and vapor deposition. The metal-clad laminate according to claim 19, wherein the metal film is a copper metal film. A printed wiring board comprising the laminate according to any one of claims 1 to 18.

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