WO2024034463A1

WO2024034463A1 - Resin composition, copper foil with resin, and printed wiring board

Info

Publication number: WO2024034463A1
Application number: PCT/JP2023/028105
Authority: WO
Inventors: 和弘大澤; 国春小川; 遥牧野; 昭典田村; 歩立岡
Original assignee: 三井金属鉱業株式会社
Priority date: 2022-08-08
Filing date: 2023-08-01
Publication date: 2024-02-15
Also published as: TW202411348A

Abstract

Provided is a resin composition that not only exhibits high adhesiveness against less rough surfaces and has excellent dielectric properties, but also can stably sustain the high adhesiveness even after a heat load is applied thereto. The resin composition contains: an arylene ether compound having a weight average molecular weight of 30000 or more, and/or a styrene-based copolymer that has, within the molecule, a reactive unsaturated bond that expresses reactivity due to heat or ultraviolet rays; and an organic filler formed of a liquid crystal polymer.

Description

Resin compositions, resin-coated copper foils, and printed wiring boards

The present invention relates to a resin composition, a resin-coated copper foil, and a printed wiring board.

Printed wiring boards are widely used in electronic devices. In particular, as electronic devices and the like have become more sophisticated in recent years, the frequency of signals has been increasing, making high-speed, large-capacity communication possible. Examples of such applications include communication servers, self-driving cars, and 5G-enabled mobile phones. There is a growing demand for printed wiring boards suitable for such high frequency applications. This high frequency printed wiring board is desired to have low transmission loss in order to be able to transmit high frequency signals without deteriorating their quality. A printed wiring board is equipped with a copper foil processed into a wiring pattern and an insulating resin base material, but transmission loss is mainly a conductor loss due to the copper foil and a dielectric loss due to the insulating resin base material. It consists of. Therefore, in a copper foil with a resin layer applied to high frequency applications, it is desirable to suppress dielectric loss caused by the resin layer. For this purpose, the resin layer is required to have excellent dielectric properties, particularly a low dielectric loss tangent.

On the other hand, various resin compositions with excellent dielectric properties, adhesion, etc. have been proposed for uses such as printed wiring boards. For example, Patent Document 1 (International Publication No. 2013/105650) discloses a copper foil with an adhesive layer that has an adhesive layer on one side of the copper foil, and this adhesive layer is made of a polyphenylene ether compound with a mass of 100% It is made of a resin composition containing 5 parts by mass or more and 65 parts by mass or less of a styrene-butadiene block copolymer. Further, Patent Document 2 (International Publication No. 2016/175326) describes a group containing an N-substituted maleimide structure in one molecule and a polyphenylene ether derivative (A) selected from the group consisting of an epoxy resin, a cyanate resin, and a maleimide compound. A resin composition containing at least one type of thermosetting resin (B) and a styrenic thermoplastic elastomer (C) is disclosed. Patent Document 3 (Japanese Unexamined Patent Publication No. 2011-225639) discloses a thermosetting resin composition containing an uncured semi-IPN composite and (D) a radical reaction initiator. This uncured semi-IPN type composite consists of (A) polyphenylene ether, (B) a butadiene polymer containing 40% or more of 1,2-butadiene units having a 1,2-vinyl group in the side chain; (C) A prepolymer formed from a crosslinking agent is said to be compatible and uncured.

International Publication No. 2013/105650 International Publication No. 2016/175326 Japanese Patent Application Publication No. 2011-225639

The present inventors have studied resin compositions that can be attached to base materials such as prepregs as primer layers (adhesive layers) as resin compositions with excellent dielectric properties and the like. The layer of this resin composition is provided in the form of a resin-coated copper foil, and this copper foil can be used as a circuit-forming copper foil. Resin compositions for the above-mentioned applications are desired to have not only excellent dielectric properties but also excellent adhesion to low-roughness surfaces (for example, the surface of low-roughness copper foil). In particular, when forming high-frequency circuits, low-roughness copper foil is desired from the perspective of reducing transmission loss, but because such copper foil has low roughness, it tends to have poor adhesion with resin compositions. It is in. In particular, when heat treatment is performed in the substrate manufacturing process, the adhesion between the copper foil and the resin composition tends to further deteriorate. Therefore, resin compositions for the above applications must not only exhibit excellent dielectric properties and high adhesion to low-roughness surfaces (for example, the surface of low-roughness copper foil), but also exhibit high adhesion even after heat load. It is desirable to be able to maintain stable sex.

The present inventors have recently discovered that by blending a predetermined arylene ether compound and/or a predetermined styrenic copolymer with an organic filler composed of a liquid crystal polymer, excellent dielectric properties (for example, a low dielectric loss tangent at 10 GHz) can be achieved. ) and low-roughness surfaces (for example, the surface of low-roughness copper foil), it is possible to provide a resin composition that not only exhibits high adhesion to low-roughness surfaces (for example, the surface of low-roughness copper foil) but also can stably maintain that high adhesion even after heat load. I gained knowledge.

Therefore, an object of the present invention is to provide a resin composition that not only exhibits excellent dielectric properties and high adhesion to low-roughness surfaces, but also can stably maintain this high adhesion even after heat load. It is in.

According to the present invention, the following aspects are provided.
[Aspect 1]
At least one of an arylene ether compound having a weight average molecular weight of 30,000 or more and a styrenic copolymer having a reactive unsaturated bond in the molecule that exhibits reactivity with heat or ultraviolet light;
An organic filler composed of liquid crystal polymer,
A resin composition containing.
[Aspect 2]
The resin composition according to aspect 1, wherein the reactive unsaturated bond is at least one selected from the group consisting of a cyanate group, a maleimide group, a terminal vinyl group, a (meth)acryloyl group, an ethynyl group, and a styryl group. thing.
[Aspect 3]
The resin composition according to aspect 1 or 2, wherein the styrenic copolymer has a styryl group as the reactive unsaturated bond.
[Aspect 4]
The resin composition according to any one of aspects 1 to 3, wherein the resin composition contains both the arylene ether compound and the styrenic copolymer.
[Aspect 5]
The resin composition according to any one of aspects 1 to 4, wherein the organic filler has a dielectric loss tangent of 0.001 or less at a frequency of 10 GHz.
[Aspect 6]
A resin-coated copper foil comprising a copper foil and a resin layer containing the resin composition according to any one of aspects 1 to 5 provided on at least one surface of the copper foil.
[Aspect 7]
The resin-coated copper foil according to aspect 6, wherein the surface of the copper foil on the resin layer side has a ten-point average roughness Rzjis of 2.0 μm or less as measured in accordance with JIS B0601-2001.
[Aspect 8]
A printed wiring board produced using the resin-coated copper foil according to aspect 6 or 7.

Resin Composition The resin composition of the present invention contains at least one of an arylene ether compound and a styrene copolymer, and an organic filler. The arylene ether compound has a weight average molecular weight of 30,000 or more, while the styrenic copolymer has a reactive unsaturated bond in its molecule that becomes reactive with heat or ultraviolet light. The organic filler is composed of liquid crystal polymer. In this way, by blending a predetermined arylene ether compound and/or a predetermined styrenic copolymer with an organic filler composed of a liquid crystal polymer, excellent dielectric properties (for example, low dielectric loss tangent at 10 GHz) and low roughness can be achieved. It is possible to provide a resin composition that not only exhibits high adhesion to rough surfaces (for example, the surface of low-roughness copper foil) but also can stably maintain its adhesion even after heat load.

As mentioned above, the present inventors have studied resin compositions that can be attached to base materials such as prepregs as primer layers (adhesive layers) as resin compositions with excellent dielectric properties and the like. The layer of this resin composition is provided in the form of a resin-coated copper foil, and this copper foil can be used as a circuit-forming copper foil. Resin compositions for the above-mentioned applications are desired to have not only excellent dielectric properties but also excellent adhesion to low-roughness surfaces (for example, the surface of low-roughness copper foil). In particular, when forming high-frequency circuits, low-roughness copper foil is desired from the perspective of reducing transmission loss, but because such copper foil has low roughness, it tends to have poor adhesion with resin compositions. It is in. In particular, when heat treatment is performed in the substrate manufacturing process, the adhesion between the copper foil and the resin composition tends to further deteriorate. In this regard, according to the resin composition of the present invention, the above-mentioned problems can be conveniently solved.

The resin composition of the present invention contains at least one of an arylene ether compound having a weight average molecular weight of 30,000 or more and a styrenic copolymer having a reactive unsaturated bond in the molecule that exhibits reactivity with heat or ultraviolet rays. Preferably, it contains both an arylene ether compound and the styrenic copolymer described above. By doing so, the above-described effects of the present invention can be more effectively achieved.

The resin composition of the present invention preferably has a dielectric loss tangent at a frequency of 10 GHz after curing of less than 0.0035, more preferably less than 0.0020, and still more preferably less than 0.0015. The lower the dielectric loss tangent is, the more preferable it is, and the lower limit is not particularly limited, but is typically 0.0001 or more.

The resin composition of the present invention preferably contains an arylene ether compound. The weight average molecular weight of this arylene ether compound is 30,000 or more, preferably 30,000 or more and 300,000 or less, more preferably 40,000 or more and 200,000 or less, particularly preferably 45,000 or more and 120,000 or less. The arylene ether compound having a weight average molecular weight of 30,000 or more is preferably a phenylene ether compound, such as polyphenylene ether. The arylene ether compound or phenylene ether compound has the following formula:

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms)
It is preferable that the compound contains a skeleton represented by the following in its molecule. Examples of phenylene ether compounds include styrene derivatives of phenylene ether compounds, phenylene ether compounds containing a maleic anhydride structure in the molecule, terminal hydroxyl group-modified phenylene ether compounds, terminal methacrylic-modified phenylene ether compounds, and terminal glycidyl ether-modified phenylene ether compounds. Can be mentioned. Examples of products of arylene ether compounds having a maleic anhydride structure in the molecule and having a weight average molecular weight of 30,000 or more include PME-80 and PME-82 manufactured by Mitsubishi Engineering Plastics Corporation.

The arylene ether compound of the present invention preferably has a reactive unsaturated bond. Alternatively, the resin composition may further include an additional arylene ether compound having a reactive unsaturated bond. In this case, the additional arylene ether compound does not need to have a weight average molecular weight of 30,000 or more. That is, the additional arylene ether compound can have a weight average molecular weight of less than 30,000 (although it may have a weight average molecular weight of 30,000 or more), for example, it can have a number average molecular weight of 500 or more and 10,000 or less. A reactive unsaturated bond is defined as an unsaturated bond that exhibits reactivity with heat or ultraviolet light. Preferred examples of reactive unsaturated bonds include cyanate groups, maleimide groups, vinyl groups, (meth)acryloyl groups, ethynyl groups, styryl groups, and combinations thereof. A styryl group is particularly preferred because it has high reactivity and allows control of the reaction (reactions are difficult to occur over time, the resin can be stored, and a long product life can be ensured).

The reactive unsaturated bond in the arylene ether compound is preferably located at or adjacent to the end of the molecular structure, since it exhibits high reactivity. For example, a 1,2-vinyl group is an example of a functional group having an unsaturated bond at the end of its molecular structure, and since the 1,2-vinyl group exhibits high reactivity, it can be used as a functional group for radical polymerization. It is common as On the other hand, in the case of ethylenically unsaturated bonds (vinyl groups not located at the ends of the molecular structure) present in the molecular chain, the reactivity decreases. Furthermore, exceptionally, when a benzene ring is adjacent to an unsaturated bond (for example, in the case of a styryl group), the reactivity is high. Therefore, the position of the reactive unsaturated bond may be a) the end of the molecular structure (regardless of whether it is the main chain or the side chain), or b) the end of the molecular structure (regardless of whether it is the main chain or the side chain). If a benzene ring is located at the position (not present), it may be located adjacent to the terminal benzene ring. For example, the arylene ether compound may have styryl groups as reactive unsaturated bonds at both ends of its molecular structure. Examples of products of arylene ether compounds having styryl groups at both ends of the molecule include OPE-2St-1200 and OPE-2St-2200 manufactured by Mitsubishi Gas Chemical Co., Ltd. (However, the arylene ether compounds of these products have a weight average molecular weight is less than 30,000).

When the resin composition of the present invention contains an arylene ether compound having a weight average molecular weight of 30,000 or more, the content is not particularly limited, but from the viewpoint of achieving both compatibility (related to peel strength) and dielectric properties. , preferably 10 parts by weight or more and 90 parts by weight or less, more preferably 15 parts by weight or more and 80 parts by weight or less, even more preferably 20 parts by weight or more and 60 parts by weight, based on 100 parts by weight of the total amount of resin components (solid content). It is as follows. In this specification, the total amount of resin components (solid content) of 100 parts by weight includes not only the polymer and resin but also the weight of additives such as reaction initiators that constitute a part of the resin. However, organic fillers are not included in the calculation.

The resin composition of the present invention preferably contains a styrenic copolymer having a reactive unsaturated bond in the molecule that exhibits reactivity with heat or ultraviolet light. The styrenic copolymer may be either hydrogenated or non-hydrogenated. That is, the styrenic copolymer is a compound containing a moiety derived from styrene, and may also contain a moiety derived from a compound having a polymerizable unsaturated group such as an olefin in addition to styrene. If a double bond is further present in a site derived from a compound having a polymerizable unsaturated group in the styrenic copolymer, the double bond may be hydrogenated or not hydrogenated. It may be. Examples of styrenic copolymers include acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate-butadiene-styrene copolymer (MBS), acrylonitrile-acrylate-styrene copolymer (AAS), and acrylonitrile-butadiene-styrene copolymer (AAS). Ethylene-styrene copolymer (AES), styrene-butadiene copolymer (SBR), styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), styrene-4- Examples include methylstyrene/isoprene/butadiene block copolymers, and combinations thereof, preferably styrene/butadiene block copolymers (SBR), styrene/4-methylstyrene/isoprene/butadiene block copolymers, and combinations thereof. Especially preferred is a styrene/4-methylstyrene/isoprene/butadiene block copolymer. The weight average molecular weight of the styrenic copolymer is not particularly limited, but is preferably 40,000 or more and 400,000 or less, more preferably 60,000 or more and 370,000 or less, particularly preferably 80,000 or more and 340,000 or less.

The styrenic copolymer used in the present invention has a reactive unsaturated bond in its molecule that becomes reactive with heat or ultraviolet light. Preferred examples of reactive unsaturated bonds include cyanate groups, maleimide groups, terminal vinyl groups, (meth)acryloyl groups, ethynyl groups, styryl groups, and combinations thereof. A styryl group is particularly preferred because it has high reactivity and allows control of the reaction (reactions are difficult to occur over time, the resin can be stored, and a long product life can be ensured).

The reactive unsaturated bonds in the styrenic copolymer are preferably located at or adjacent to the ends of the molecular structure in view of exhibiting high reactivity. For example, a 1,2-vinyl group is an example of a functional group that has an unsaturated bond at the end of its molecular structure, but the 1,2-vinyl group (terminal vinyl group) is highly reactive and therefore difficult to radically polymerize. It is a common functional group that can be used. Therefore, a styrenic copolymer having such a functional group can be said to be a styrenic copolymer having a reactive unsaturated bond in its molecule that exhibits reactivity with heat or ultraviolet rays. On the other hand, in the case of ethylenically unsaturated bonds (vinyl groups not located at the ends of the molecular structure) present in the molecular chain, the reactivity decreases. Therefore, a styrenic copolymer having such an unsaturated bond cannot be said to be a styrenic copolymer having a reactive unsaturated bond in its molecule that exhibits reactivity with heat or ultraviolet rays. An example of a product of a styrene copolymer having no unsaturated bond at the end of its molecular structure is TR2003 manufactured by JSR Corporation. In addition, as an exception, when a benzene ring is adjacent to an unsaturated bond (for example, in the case of a styryl group), it has high reactivity. It can be said that it is a styrenic copolymer with Therefore, the position of the reactive unsaturated bond may be a) the end of the molecular structure (regardless of whether it is the main chain or the side chain), or b) the end of the molecular structure (regardless of whether it is the main chain or the side chain). If a benzene ring is located at the position (not present), it may be located adjacent to the terminal benzene ring. Examples of products of styrenic copolymers having reactive unsaturated bonds include Septon ^(R) V9461 (contains a styryl group) manufactured by Kuraray Co., Ltd., and Ricon ^(R) 100, 181 and 184 (1,2- Styrene-butadiene copolymers having vinyl groups), Epofriend AT501 and CT310 (styrene-butadiene copolymers having 1,2-vinyl groups) manufactured by Daicel Corporation. Note that "exhibiting reactivity with heat or ultraviolet light" means exhibiting reactivity under heating conditions or ultraviolet irradiation conditions that are sufficient to cure the base material (for example, prepreg) that is suitably used in combination with the resin composition of the present invention. This means that the heating temperature under such conditions is typically about 160 to 230°C.

Preferably, the styrenic copolymer has modified styrene butadiene. Alternatively, the resin composition may further include an additional styrenic copolymer with modified styrene butadiene. In this case, as the additional styrenic copolymer, the same styrenic copolymer described above can be used, except that it does not need to have a reactive unsaturated bond. That is, the additional styrenic copolymer can be one that does not have reactive unsaturated bonds (although it may have reactive unsaturated bonds). The modified styrene-butadiene may be any styrene-butadiene that has been chemically modified by introducing various functional groups, such as amine-modified, pyridine-modified, carboxy-modified, etc., but amine-modified is preferred. An example of a styrenic copolymer having modified styrene-butadiene includes Tuftec ^(R) MP10 manufactured by Asahi Kasei Corporation, which is a hydrogenated styrene-butadiene block copolymer and is an amine-modified product. An example of an unmodified styrene copolymer is TR2003 manufactured by JSR Corporation, which is a styrene-butadiene block copolymer. (not a styrenic copolymer with bonds in the molecule).

The content of the styrenic copolymer having a reactive unsaturated bond that exhibits reactivity with heat or ultraviolet rays in the resin composition of the present invention is not particularly limited, but from the viewpoint of achieving both compatibility and dielectric properties, the resin component (solid) 20 parts by weight or more and 99.5 parts by weight or less, more preferably 30 parts by weight or more and 90 parts by weight or less, even more preferably 40 parts by weight or more and 70 parts by weight or less, based on 100 parts by weight of the total amount of .

In the resin composition of the present invention, the total content of the arylene ether compound having a weight average molecular weight of 30,000 or more and the styrenic copolymer having a reactive unsaturated bond in the molecule that exhibits reactivity with heat or ultraviolet rays is not particularly limited. , preferably 30 parts by weight or more and 99.5 parts by weight or less, more preferably 40 parts by weight or more and 90 parts by weight or less, even more preferably 50 parts by weight or more and 85 parts by weight, based on 100 parts by weight of the total amount of resin components (solid content). Parts by weight or less.

The resin composition of the present invention includes an organic filler made of liquid crystal polymer (LCP). By adding a liquid crystal polymer as a filler, not only can excellent dielectric properties be imparted to the resin composition, but also high adhesion to low roughness surfaces can be prevented from deteriorating even after heat load. This ability to suppress thermal deterioration is an advantage that cannot be obtained with inorganic fillers. Furthermore, fillers made of liquid crystal polymers have excellent dispersibility in other resin components. For example, an organic filler made of polytetrafluoroethylene (PTFE) is very difficult to disperse in a resin component, but an organic filler made of a liquid crystal polymer is advantageous in that it does not have such drawbacks. Preferably, the organic filler is in the form of liquid crystal polymer particles. Commercially available liquid crystal polymer particles can be used, and for example, XYDAR ^(R) LF-31P (manufactured by ENEOS Corporation) can be preferably used as a powder grade liquid crystal polymer. The particle size of the liquid crystal polymer particles is not particularly limited as long as it can be dispersed in the resin composition as an organic filler and exhibit the desired performance, but it is preferable that the average particle size D50 of the liquid crystal polymer particles is 0.1 to 10 μm. , more preferably 0.5 to 9 μm, still more preferably 1 to 8 μm. The average particle diameter D50 of the liquid crystal polymer particles can be measured using a laser diffraction scattering particle size distribution analyzer.

The content of the organic filler is not particularly limited, but from the viewpoint of ease of filler dispersion, fluidity of the resin composition, etc., the content of the organic filler is 5 parts by weight based on 100 parts by weight of the total amount of the resin components (solid content) mentioned above. 300 parts by weight or less, more preferably 10 parts by weight or more and 200 parts by weight or less, still more preferably 15 parts by weight or more and 200 parts by weight, particularly preferably 15 parts by weight or more and 150 parts by weight or less, most preferably 25 parts by weight. The amount is 75 parts by weight or less.

The organic filler preferably has a dielectric loss tangent of 0.001 or less at a frequency of 10 GHz, more preferably 0.0009 or less, and still more preferably 0.0008 or less. The lower the dielectric loss tangent is, the more preferable it is, and the lower limit is not particularly limited, but is typically 0.0001 or more.

The resin composition of the present invention may contain additives commonly added to resins and polymers. Examples of additives include reaction initiators, reaction promoters, flame retardants, silane coupling agents, dispersants, antioxidants, and the like.

Resin-coated copper foil The resin composition of the present invention is preferably used as a resin for resin-coated copper foil. That is, according to a preferred embodiment of the present invention, a resin-coated copper foil is provided that includes a copper foil and a resin layer containing a resin composition provided on at least one surface of the copper foil. Typically, the resin composition is in the form of a resin layer, and the resin composition is applied to the copper foil using a gravure coating method so that the thickness of the resin layer after drying becomes a predetermined value. Dry to obtain resin-coated copper foil. The method of this coating is arbitrary, but in addition to the gravure coating method, a die coating method, a knife coating method, etc. can be adopted. In addition, it is also possible to apply using a doctor blade, bar coater, or the like.

As mentioned above, the resin composition of the present invention not only has excellent dielectric properties (e.g., low dielectric loss tangent at 10 GHz) and high adhesion to low-roughness surfaces (e.g., the surface of low-roughness copper foil). , it is possible to maintain stable high adhesion to low-roughness surfaces even after heat load. Therefore, the resin-coated copper foil has various advantages brought about by such a resin composition. For example, in a resin-coated copper foil, the lower limit of the peel strength between the resin layer and the copper foil (that is, the normal peel strength) measured in accordance with JIS C 6481-1996 when the resin layer is cured is as follows: Preferably it is 0.5 kgf/cm or more, more preferably 0.8 kgf/cm or more, still more preferably 1.0 kgf/cm or more, particularly preferably 1.2 kgf/cm or more. The higher the peel strength, the better, and its upper limit is not particularly limited, but is typically 2.0 kgf/cm or less.

The thickness of the resin layer is not particularly limited, but a thicker one is preferable in order to ensure peel strength, and a thinner thickness of the laminated substrate is preferable, so an appropriate thickness exists. The thickness of the resin layer is preferably 1 μm or more and 50 μm or less, more preferably 1.5 μm or more and 30 μm or less, particularly preferably 2 μm or more and 20 μm or less, and most preferably 2.5 μm or more and 10 μm or less. By falling within these ranges, the various properties of the present invention described above can be more effectively realized, and the resin layer can be easily formed by applying the resin composition.

The copper foil may be an electrolytic foil or a rolled metal foil (so-called raw foil), or it may be in the form of a surface-treated foil that has been surface-treated on at least one side. Good too. Surface treatment is a variety of surface treatments performed to improve or impart certain properties to the surface of metal foil (for example, rust prevention, moisture resistance, chemical resistance, acid resistance, heat resistance, and adhesion to a substrate). It can be. The surface treatment may be performed on one side of the metal foil or on both sides of the metal foil. Examples of surface treatments performed on copper foil include rust prevention treatment, silane treatment, roughening treatment, barrier formation treatment, and the like.

The ten-point average roughness Rzjis of the surface of the copper foil on the resin layer side measured in accordance with JIS B0601-2001 is preferably 2.0 μm or less, more preferably 1.5 μm or less, and even more preferably 1 .0 μm or less, particularly preferably 0.7 μm or less, and most preferably 0.5 μm or less. Within this range, transmission loss in high frequency applications can be desirably reduced. That is, it is possible to reduce the conductor loss caused by the copper foil, which can increase due to the skin effect of the copper foil, which becomes more pronounced as the frequency increases, and further reduce the transmission loss. The lower limit of the ten-point average roughness Rzjis on the surface of the copper foil on the resin layer side is not particularly limited, but from the viewpoint of improving adhesion with the resin layer and heat resistance, Rzjis is preferably 0.01 μm or more, more preferably 0. It is .03 μm or more, more preferably 0.05 μm or more.

The thickness of the copper foil is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less, more preferably 0.5 μm or more and 70 μm or less, even more preferably 1 μm or more and 50 μm or less, and particularly preferably 1.5 μm or more and 30 μm or less. , most preferably 2 μm or more and 20 μm or less. A thickness within these ranges has the advantage that fine circuitry can be formed. However, in cases where the thickness of the copper foil is, for example, 10 μm or less, the resin-coated copper foil of the present invention may be coated with a resin layer on the copper foil surface of the carrier-coated copper foil, which is provided with a release layer and a carrier to improve handling properties. It may also be formed by

From the viewpoint of ensuring adhesion with the resin layer, the base material such as prepreg preferably contains a resin having a reactive unsaturated bond in the molecule, and from the viewpoint of compatibility with the resin layer, polyphenylene ether is preferably used. Preferably, it contains a resin. Commercially available examples of base materials that satisfy both the requirements of containing a resin having a reactive unsaturated bond in the molecule and containing a polyphenylene ether resin include the MEGTRON 6 series, MEGTRON 7 series, and MEGTRON 8 series manufactured by Panasonic Corporation. It will be done. Conventionally, it was difficult to ensure adhesion with a resin layer and even a low-roughness copper foil with a base material having a low dielectric constant and a low dielectric loss tangent as exemplified here, but by using the resin composition of the present invention, it is possible to achieve sufficient adhesion. It is possible to ensure good adhesion. In particular, stable high adhesion to low-roughness copper foil can be maintained even after heat load. Therefore, according to a preferred embodiment of the present invention, a base material (for example, prepreg) and a resin layer containing the resin composition of the present invention (or resin-coated copper foil of the present invention) provided on one or both sides of the base material. A laminate is provided.

Printed Wiring Board The resin composition or resin-coated copper foil of the present invention is preferably used for producing a printed wiring board. That is, according to a preferred embodiment of the present invention, a printed wiring board including the resin-coated copper foil or a printed wiring board manufactured using the resin-coated copper foil is provided. In this case, the resin layer of the resin-coated copper foil is hardened. The printed wiring board according to this embodiment includes a layered structure in which an insulating resin layer and a copper layer are laminated in this order. A known layer structure can be used for the printed wiring board. Specific examples of printed wiring boards include single-sided or double-sided printed wiring boards in which the resin-coated copper foil of the present invention is adhered to one or both sides of a prepreg to form a cured laminate, and circuits are formed on the same, and multilayers made of these. Examples include printed wiring boards. Other specific examples include flexible printed wiring boards in which a circuit is formed by forming the resin-coated copper foil of the present invention on a resin film, COF, TAB tape, build-up multilayer wiring boards, and resin-coated copper foils on semiconductor integrated circuits. Examples include direct build-up on wafer, in which lamination of coated copper foil and circuit formation are alternately repeated. In particular, the resin-coated copper foil of the present invention can be preferably applied as an insulating layer and a conductive layer for printed wiring boards for high-frequency digital communications in network equipment. Examples of such network devices include (i) in-base station servers, routers, etc., (ii) in-company networks, and (iii) backbone systems for high-speed mobile communications.

The present invention will be explained in more detail with reference to the following examples.

Examples 1 to 12
(1) Preparation of resin varnish First, the following arylene ether compound, styrene copolymer, additive, organic filler, and inorganic filler were prepared as raw materials for resin varnish.
<Arylene ether compound>
-OPE-2St-1200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., phenylene ether compound having styryl groups at both ends of the molecule, number average molecular weight approximately 1200)
-OPE-2St-2200 (manufactured by Mitsubishi Gas Chemical Co., Ltd., phenylene ether compound having styryl groups at both ends of the molecule, number average molecular weight approximately 2200)
-PME-82 (manufactured by Mitsubishi Engineering Plastics Co., Ltd., a phenylene ether compound containing a maleic anhydride structure in the molecule, weight average molecular weight approximately 56,000)
<Styrenic copolymer>
- Septon ^(R) V9461 (manufactured by Kuraray Co., Ltd., hydrogenated styrene/4-methylstyrene/isoprene/butadiene block copolymer with styryl group, weight average molecular weight approximately 296,000)
-TR2003 (manufactured by JSR Corporation, styrene-butadiene block copolymer, weight average molecular weight approximately 95,700)
- Tuftec ^(R) MP10 (manufactured by Asahi Kasei Corporation, hydrogenated styrene-butadiene block copolymer, amine-modified product, weight average molecular weight approximately 60,000)
<Additive (reaction initiator)>
- Perbutyl P (manufactured by NOF Corporation, peroxide)
<Inorganic filler>
-SC4050-MOT (manufactured by Admatex Co., Ltd., silica slurry, average particle size D50: 1.0 μm, surface vinyl silane treatment)
<Organic filler>
-XYDAR ^(R) LF-31P (manufactured by ENEOS Corporation, liquid crystal polymer (LCP) powder, average particle size D50: 5 to 7 μm, dielectric loss tangent at 10 GHz: 0.0007)

The number average molecular weight and weight average molecular weight of the above-mentioned arylene ether compound and styrene copolymer are values obtained by measurement using GPC (gel permeation chromatography) method under the following conditions. The above molecular weights are relative values based on polystyrene.
・Detector: Differential refractive index detector RI (manufactured by Tosoh Corporation, RI-8020, sensitivity 32)
・Column: TSKgel GMH _HR -M, 2 (7.8mm x 30cm, manufactured by Tosoh Corporation)
・Solvent: Chloroform ・Flow rate: 1.0mL/min
・Column temperature: 40℃
・Injection volume: 0.2mL
・Standard sample: Manufactured by Tosoh Corporation, monodisperse polystyrene ・Data processing: Manufactured by Toray Research Center Corporation, GPC data processing system

Weigh out the above raw material components into a round flask at the blending ratio (weight ratio) shown in Tables 1 and 2, and add the mixed solvent so that the concentration of solids derived from the raw material components becomes the value shown in Tables 1 and 2. Ta. This mixed solvent is a mixture of methyl ethyl ketone (MEK) and toluene so that the MEK ratio (wt%) is shown in Tables 1 and 2. A mantle heater, a stirring blade, and a flask lid with a reflux condenser tube were installed in a round flask containing the raw material components and mixed solvent, and the temperature was raised to 60 °C while stirring, and stirring was continued at 60 °C for 2 hours. The raw material components were dissolved or dispersed. The resin varnish obtained after stirring was allowed to cool. In this way, resin varnishes having solid content concentrations shown in Tables 1 and 2 were obtained.

(2) Production of electrolytic copper foil Electrolytic copper foil was produced by the following method. Electrolysis was carried out in a copper sulfate solution using a titanium rotating electrode (surface roughness Ra: 0.20 μm) as the cathode and a dimensionally stable anode (DSA) as the anode at a solution temperature of 45°C and a current density of 55A/ ^dm2 . , an electrolytic copper foil was produced as a raw foil. The composition of this copper sulfate solution is: copper concentration 80 g/L, free sulfuric acid concentration 140 g/L, bis(3-sulfopropyl) disulfide concentration 30 mg/L, diallyldimethylammonium chloride polymer concentration 50 mg/L, and chlorine concentration 40 mg/L. And so. Particulate protrusions were formed on the surface of the raw foil on the electrolyte side. The formation of particulate protrusions was performed in a copper sulfate solution (copper concentration: 13 g/L, free sulfuric acid concentration 55 g/L, 9-phenylacridine concentration 140 mg/L, chlorine concentration: 35 mg/L) at a solution temperature of 30°C and an electric current. This was carried out by electrolyzing at a density of 50 A/dm ² .

A zinc-nickel coating, a chromate layer, and a silane layer were sequentially formed on the electrolyte side of the raw foil obtained in this manner under the conditions shown below.
<Zinc-nickel film formation>
・Potassium pyrophosphate concentration: 80g/L
・Zinc concentration: 0.2g/L
・Nickel concentration: 2g/L
・Liquid temperature: 40℃
・Current density: 0.5A/ ^dm2
<Chromate layer formation>
・Chromic acid concentration: 1g/L, pH 11
・Solution temperature: 25℃
・Current density: 1A/dm ²
<Silane layer formation>
・Silane coupling agent: 3-aminopropyltrimethoxysilane (3 g/L aqueous solution)
・Liquid processing method: Shower processing

The surface treated surface of this electrolytic copper foil has a ten-point average roughness Rzjis of 0.5 μm (according to JIS B0601-2001), and the particle-like protrusions have an average particle diameter of 100 nm as determined by a scanning electron microscope image. The density was 205 pieces/ ^μm2 . The total thickness of the electrolytic copper foil including the surface treated surface was 18 μm.

(3) Preparation of resin film The resin varnish obtained in the above (1) is applied to the surface of a release film (AFLEX ^(R) manufactured by AGC Corporation) using a comma coater to coat the resin after drying. It was coated to a thickness of 20 μm and dried in an oven at 150° C. for 3 minutes to obtain a B-stage resin. The release film was peeled off from the obtained B-stage resin, two sheets of B-stage resin were laminated, and vacuum press molding was performed at 200° C. for 90 minutes at 20 kgf/cm ² to a thickness of 40 μm. A resin film was obtained.

(4) Preparation of single-sided layered board The resin varnish obtained in the above (1) is applied to the surface of the electrolytic copper foil using a gravure coater so that the thickness of the resin after drying is 4 μm, It was dried in an oven at 150°C for 2 minutes to obtain a resin-coated copper foil. A plurality of sheets of prepreg (manufactured by Panasonic Corporation, MEGTRON 7 series "R-5680") are stacked to a thickness of 0.2 mm, and the resin-coated copper foil is laminated thereon so that the resin is in contact with the prepreg, Vacuum press molding was performed at 190° C. for 90 minutes at 30 kgf/cm ² to obtain a single-layered substrate.

(5) Various evaluations The following evaluations were performed on the produced resin films and single-layered substrates.

<Normal peel strength>
Copper wiring with a wiring width of 10 mm and a wiring thickness of 18 μm was formed on a single-layered board by a subtractive method, and the peel strength (kgf/cm) was measured at room temperature (for example, 25° C.) in accordance with JIS C 6481-1996. The measurement was performed five times, and the average value was taken as the peel strength value. The peel strength measured here reflects four peeling modes: prepreg/resin interface peeling, resin cohesive failure, phase interface peeling within the resin layer, and resin/copper foil interface peeling. The higher the value, the better the adhesion to a base material such as a prepreg, the strength of the resin layer, and the adhesion of the resin to a low-roughness foil. As a result, as shown in Tables 1 and 2, in all of Examples 1 to 12, the normal peel strength was 0.5 kgf/cm or more, confirming high adhesion to low roughness surfaces.

<Heat-resistant peel strength maintenance rate>
The method was the same as the normal peel strength measurement described above, except that copper wiring with a wiring width of 10 mm and a wiring thickness of 18 μm was formed on a single-layered board by the subtractive method, and then heat-treated by floating it in a 288°C solder bath for 5 minutes. The post-heat peel strength (kgf/cm) was measured according to the procedure. The heat-resistant peel strength retention rate (%) was calculated by multiplying the value obtained by dividing the post-heat peel strength value by the normal peel strength value by 100. The results are shown in Tables 1 and 2. The resin compositions of Examples 1 to 7 had heat-resistant peel strength retention rates of 95% or more, higher than Examples 8 to 12 (comparative examples), and remained low even after heat load. It was found that high adhesion to rough surfaces could be stably maintained.

<Dielectric loss tangent>
The dielectric loss tangent of the resin film at 10 GHz was measured by the perturbation cavity resonator method. This measurement was performed in accordance with JIS R 1641 using a measuring device (a resonator manufactured by KEYCOM and a network analyzer manufactured by KEYSIGHT) after cutting the resin film according to the sample size of the resonator. The results were as shown in Tables 1 and 2.

Claims

At least one of an arylene ether compound having a weight average molecular weight of 30,000 or more and a styrenic copolymer having a reactive unsaturated bond in the molecule that exhibits reactivity with heat or ultraviolet light;
An organic filler composed of liquid crystal polymer,
A resin composition containing.
The resin according to claim 1, wherein the reactive unsaturated bond is at least one selected from the group consisting of a cyanate group, a maleimide group, a terminal vinyl group, a (meth)acryloyl group, an ethynyl group, and a styryl group. Composition.
The resin composition according to claim 1 or 2, wherein the styrenic copolymer has a styryl group as the reactive unsaturated bond.
The resin composition according to claim 1 or 2, wherein the resin composition contains both the arylene ether compound and the styrenic copolymer.
The resin composition according to claim 1 or 2, wherein the organic filler has a dielectric loss tangent of 0.001 or less at a frequency of 10 GHz.
A resin-coated copper foil comprising a copper foil and a resin layer containing the resin composition according to claim 1 and provided on at least one surface of the copper foil.
The resin-coated copper foil according to claim 6, wherein the surface of the copper foil on the resin layer side has a ten-point average roughness Rzjis of 2.0 μm or less as measured in accordance with JIS B0601-2001.
A printed wiring board manufactured using the resin-coated copper foil according to claim 6.