JP6880585B2 - Composite films for electronic devices, printed wiring boards and their manufacturing methods that use signals in the high frequency band - Google Patents

Description

The present invention relates to a composite film for electronic devices, a printed wiring board, and a method for manufacturing the same, which uses a signal in a high frequency band.

In recent years, electronic devices have become smaller, lighter, more multifunctional, etc., and along with this, LSIs (Large Scale Integration), chip parts, etc. have become more integrated, and their forms have also become multi-pin and miniaturized. Is changing rapidly. Therefore, in order to improve the mounting density of electronic components, the development of fine wiring of multilayer printed wiring boards is underway. As a multilayer printed wiring board that meets these requirements, a multilayer printed wiring board with a build-up structure that uses an insulating resin film that does not contain glass cloth as an insulating layer (hereinafter, also referred to as "build-up layer") instead of a prepreg. However, it is becoming mainstream as a printed wiring board suitable for weight reduction, miniaturization, and miniaturization.

The build-up layer is required to have low thermal expansion in order to improve the processing dimensional stability and reduce the amount of warpage after mounting the semiconductor. One of the methods for low thermal expansion of the build-up layer is a method of highly filling an inorganic filler. For example, by using 40% by mass or more of the build-up layer as a silica filler, the build-up layer can be reduced in thermal expansion (see Patent Documents 1 to 3).

JP-A-2007-87982 Japanese Unexamined Patent Publication No. 2009-280758 Japanese Unexamined Patent Publication No. 2014-136779

Computers, information and telecommunications equipment, etc. have become more sophisticated and sophisticated in recent years, and in order to process a large amount of data at high speed, the signals to be handled tend to have higher frequencies. In particular, the frequency range of radio waves used for mobile phones and satellite broadcasting is in the high frequency range of the GHz band, and in order to suppress transmission loss due to high frequency, relative dielectric is used as an organic material used in the high frequency range. A material having a low rate and dielectric loss tangent is desired.
Further, the build-up layer is required to have embedding property in unevenness of a circuit or the like (hereinafter, may be simply referred to as "embedding property"), surface smoothness, and high adhesiveness to plated copper. However, it is difficult to obtain surface flatness and high adhesiveness to plated copper with a material highly filled with an inorganic filler as described in Patent Documents 1 to 3.

Therefore, the present invention has been made in view of such a situation, and has a low dielectric loss tangent, excellent embedding property in irregularities of circuits and the like, excellent surface smoothness, and high adhesiveness to plated copper. It is an object of the present invention to provide a composite film for electronic devices using a signal in a high frequency band, and to provide a printed wiring board containing a cured product of the composite film for electronic devices, and a method for manufacturing the printed wiring board. ..

As a result of intensive research to solve the above problems, the present inventors have obtained a layer A having a minimum melt viscosity in a specific range at a predetermined temperature and a layer B having a minimum melt viscosity of a specific value or more at a predetermined temperature. It has been found that the composite film having can solve the above-mentioned problems, and the present invention has been completed.

That is, the present invention relates to the following [1] to [9].
[1] A high-frequency band having a layer A having a minimum melt viscosity at 80 to 150 ° C. of 100 to 4,000 Pa · s and a layer B having a minimum melt viscosity at 80 to 150 ° C. of 50,000 Pa · s or more. Composite film for electronic devices that uses signals.
[2] A composite film for an electronic device using a signal in the high frequency band according to the above [1], wherein the thickness of the B layer is 1 to 5 μm.
[3] A composite film for an electronic device using a signal in the high frequency band according to the above [1] or [2], wherein the total thickness of the A layer and the B layer is 15 to 50 μm.
[4] The above-mentioned [1] to [3], wherein the layer A contains a polyimide compound having a structural unit derived from a maleimide compound and a structural unit derived from a diamine compound, and an inorganic filler. Composite film for electronic devices that uses signals in the high frequency band.
[5] For electronic devices using the high-frequency band signal according to any one of [1] to [4] above, wherein the B layer contains a polyfunctional epoxy resin and a phenolic hydroxyl group-containing polybutadiene-modified polyamide resin. Composite film.
[6] A composite film for electronic devices using a signal in the high frequency band according to any one of [1] to [5] above, wherein the cured product has a dielectric loss tangent of 0.005 or less at 5 GHz.
[7] A printed wiring board containing a cured product of the composite film for electronic devices according to any one of the above [1] to [6].
[8] A method for manufacturing a printed wiring board, comprising the step (1) of laminating the composite film for electronic devices according to any one of the above [1] to [6] on one side or both sides of a base material.
[9] Using the composite film for electronic devices according to any one of [1] to [6] above, the A layer side of the composite film for electronic devices is attached to a substrate having a step due to a circuit or a component on the surface. , The process of filling the step,
A step of curing the A layer and the B layer of the composite film for electronic devices,
A step of forming a circuit on the surface of the composite film for electronic devices on the B layer side by a semi-additive method.
A method for manufacturing a printed wiring board.

According to the present invention, a composite film for electronic devices using a signal in a high frequency band, which has a low dielectric loss tangent, excellent embedding property in irregularities such as circuits, excellent surface smoothness, and high adhesion to plated copper. , And a printed wiring board containing a cured product of the composite film for electronic devices, and a method for manufacturing the printed wiring board.

It is a figure which showed typically one aspect of the composite film of this invention.

Hereinafter, embodiments of the present invention will be described in detail. In this specification, a numerical range (X and Y are real numbers) that are greater than or equal to X and less than or equal to Y may be expressed as "X to Y". For example, the description "0.1 to 2" indicates a numerical range of 0.1 or more and 2 or less, and the numerical range includes 0.1, 0.34, 1.03, 2, and the like.

In the present specification, the "composite film" includes both a composite film in which the contained resin composition is uncured and a composite film in which the contained resin composition is semi-cured (so-called B-stage shape).
Further, in the present specification, the "composite" of the composite film means that the film is formed of a plurality of resin layers, and if the embodiment is included, the composite film is further composed of a support, a protective film, and the like. It may have other layers.

Further, in the present specification, the "interlayer insulating layer" is a layer located between two conductor layers and for insulating the conductor layer. Examples of the "interlayer insulating layer" in the present specification include a cured product of a composite film. In addition, in this specification, a "layer" includes a layer which is partially missing, and a layer in which a via or a pattern is formed.

[Composite film for electronic devices that uses signals in the high frequency band]
The present invention
Uses high frequency band signals with layer A having a minimum melt viscosity of 100-4,000 Pa · s at 80-150 ° C and layer B having a minimum melt viscosity of 50,000 Pa · s or more at 80-150 ° C. This is a composite film for electronic devices (hereinafter, may be simply referred to as "composite film").

The composite film of the present invention may have the A layer and the B layer, and a support may be provided on the surface of the B layer opposite to the A layer. In this case, the configuration is A layer / B layer / support. Examples of the support include a polyolefin film such as polyethylene, polypropylene, and polyvinyl chloride; a polyester film such as polyethylene terephthalate (hereinafter, also referred to as “PET”) and polyethylene naphthalate; various plastics such as a polycarbonate film and a polyimide film. Examples include film. Further, a metal foil such as a copper foil or an aluminum foil, a paper pattern, or the like may be used. The support and the protective film described later may be subjected to surface treatment such as matte treatment and corona treatment. Further, the support may be subjected to a mold release treatment with a silicone resin-based mold release agent, an alkyd resin-based mold release agent, a fluororesin-based mold release agent, or the like.
The thickness of the support is not particularly limited, but is preferably 10 to 150 μm, more preferably 25 to 50 μm.

The composite film of the present invention may be provided with a protective film. For example, an embodiment in which a protective film is provided on the surface of the A layer opposite to the B layer can be mentioned. In this case, for example, the configuration is a protective film / A layer / B layer, a protective film / A layer / B layer / support, and the like.
Examples of the protective film include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Further, the protective film may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, etching treatment, and mold release treatment, if necessary.
The support may be used as a protective film.

The composite film of the present invention is produced, for example, by a method of forming a B layer on the support, forming an A layer on the B layer, and forming a protective layer on the A layer as needed. can do. To form the B layer, a varnish for layer B, which will be described later, is applied to the support and then heat-dried, and then a varnish for layer A, which will be described later, is applied and then heat-dried. Can be done. As a method of applying the varnish, for example, a coating device such as a comma coater, a bar coater, a kiss coater, a roll coater, a gravure coater, or a die coater can be used. It is preferable that these coating devices are appropriately selected depending on the film thickness.
The drying conditions after coating are not particularly limited, and may be appropriately determined according to the type of solvent. For example, the drying temperature is preferably 50 to 130 ° C., more preferably 70 to 110 ° C. when forming the A layer. When forming the A layer, the drying time can be, for example, 1 to 10 minutes. For example, the drying temperature is preferably 50 to 150 ° C., more preferably 100 to 145 ° C. when forming the B layer. When forming the B layer, the drying time can be, for example, 1 to 10 minutes.
In the above drying, the content of the volatile component (mainly an organic solvent) in the layer A or B after drying is preferably 10% by mass or less, and preferably 6% by mass or less. It is more preferable to dry.

Further, the composite film of the present invention can also be produced by preparing a film of layer A and a film of layer B, respectively, and laminating them by thermocompression bonding and a laminator or the like at a softening temperature or higher.

In the composite film of the present invention, the thickness of the layer A is preferably a to 2a, more preferably 1.1a to 1.5a, in order to embed the uneven height a of the circuit. When the thickness of the A layer is a or more, sufficient embedding property can be ensured when the unevenness of the circuit is embedded, and the surface layer of the composite film after embedding tends to be easily kept flat. On the other hand, if it is 2a or less, the thickness of the substrate tends to be easy and the warpage tends to be low, which is preferable.

On the other hand, the B layer is a layer that can be applied to the semi-additive method. In order to ensure surface flatness and high adhesiveness to plated copper, the thickness of the B layer is preferably 1 to 5 μm, more preferably 1 to 3 μm, and 1.5 to 3 μm. Is even more preferable. If the thickness of the B layer is 1 μm or more, it is easy to prevent the B layer from breaking and exposing the A layer to the surface when embedding in the unevenness of the circuit, and the B layer elutes and disappears in the desmear process. There is little risk of doing it. On the other hand, if the thickness is 5 μm or less, it is easy to suppress a decrease in surface flatness and the substrate can be made thinner, which is preferable.

Layer A has a minimum melt viscosity of 100 to 4,000 Pa · s at 80 to 150 ° C. Within this range, the layer A can be flowed at 80 to 150 ° C., which is preferable from the viewpoint of embedding property. The minimum melt viscosity of the A layer at 80 to 150 ° C. is more preferably 500 to 2,000 Pa · s, and even more preferably 700 to 2,000 Pa · s. Here, the minimum melt viscosity is the viscosity when the resin composition is melted before the start of curing.
When the minimum melt viscosity at 80 to 150 ° C. is 100 Pa · s or more, the fluidity of the film does not become too large, it becomes easy to maintain the surface flatness of the composite film after embedding, and the thickness of the substrate varies. Can be suppressed. Further, when it is 4,000 Pa · s or less, the fluidity becomes good and it becomes easy to embed the unevenness of the wiring.

On the other hand, the B layer has a minimum melt viscosity of 50,000 Pa · s or more at 80 to 150 ° C. As for the B layer, the B layer maintains a constant thickness when the composite film is embedded in the circuit, and the surface flatness of the composite film after embedding is easily maintained. From the same viewpoint, the minimum melt viscosity of the B layer at 80 to 150 ° C. is preferably 50,000 to 100,000 Pa · s, more preferably 50,000 to 75,000 Pa · s, 60. It is more preferably 000 to 75,000 Pa · s, and particularly preferably 63,000 to 70,000 Pa · s.

The composite film of the present invention can be cured by heat or active energy rays. Examples of the active energy ray include electromagnetic waves such as ultraviolet rays, visible rays, infrared rays, and X-rays; and particle beams such as α-rays, γ-rays, and electron beams. Among these, ultraviolet rays are preferable.

An example of the composite film of the present invention is shown in FIG. 1 as a schematic cross-sectional view. The composite film according to the present invention includes a layer A and a layer B 2, and if necessary, a support 3 and / or a protective film 4.
There is no clear interface between the A layer 1 and the B layer 2. For example, a part of the constituent components of the A layer 1 and a part of the constituent components of the B layer 2 are compatible with each other. And / or may be in a mixed state.

In the composite film of the present invention, the components of each layer are not particularly limited as long as the above conditions are satisfied, but the components of the A layer and the B layer will be described below as an example of the embodiment.

[Components of layer A]
Examples of the component of the A layer include a resin composition. As the resin composition, for example, a resin composition containing a polyimide compound (a1) having a structural unit derived from a maleimide compound and a structural unit derived from a diamine compound and an inorganic filler (a2) is preferable, and the inorganic composition is particularly preferable. It is more preferable that the content of the filler (a2) is 55% by volume or more with respect to the solid content of the resin composition. Hereinafter, each component will be described in detail.

<Polyimide compound (a1)>
The polyimide compound (a1) has a structural unit derived from a maleimide compound and a structural unit derived from a diamine compound. The maleimide compound preferably contains an aliphatic maleimide compound.
The aliphatic maleimide compound preferably has 6 to 40 carbon atoms between the imide groups, and preferably has at least 2 N-substituted maleimide groups. By using the polyimide compound (a1) having a structural unit derived from the aliphatic maleimide compound, the dielectric loss tangent is low and the film tends to be easy to handle.
Examples of the aliphatic maleimide compound include 1,6-bismaleimide- (2,2,4-trimethyl) hexane, a binder-type long-chain alkylbismaleimide of pyrrolylonic acid, and the like. These may be used alone or in combination of two or more. As the aliphatic maleimide, 1,6-bismaleimide- (2,2,4-trimethyl) hexane is more preferable from the viewpoint of having a low coefficient of thermal expansion and a high glass transition temperature.

Further, the maleimide compound may contain a maleimide compound other than the aliphatic maleimide compound, and the maleimide compound is not particularly limited as long as it is a maleimide compound having two or more N-substituted maleimide groups. For example, bis (4-maleimidephenyl) methane, polyphenylmethanemaleimide, bis (4-maleimidephenyl) ether, bis (4-maleimidephenyl) sulfone, 3,3'-dimethyl-5,5'-diethyl-4, Examples thereof include 4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide, and 2,2-bis [4- (4-maleimidephenoxy) phenyl] propane. These may be used alone or in combination of two or more. Among these, 2,2-bis [4- (4-maleimidephenoxy) phenyl] propane is preferable from the viewpoint of adhesiveness to the conductor and mechanical properties.

The content of the structural unit derived from the aliphatic maleimide compound in the polyimide compound (a1) is preferably 5% by mass or more, more preferably 10% by mass or more in terms of the amount charged. The upper limit is not particularly limited and may be 100% by mass, but is preferably 80% by mass or less, more preferably 60% by mass or less, still more preferably 40% by mass or less, and particularly preferably 30% by mass or less. When the content of the structural unit derived from the aliphatic maleimide compound is within the above range, better high frequency characteristics and film handleability tend to be obtained in the resin composition.
The content of the structural unit derived from the aliphatic maleimide compound is preferably 5 to 50% by mass, more preferably 10 to 40% by mass in terms of the amount charged, with respect to the total content of the structural unit derived from the maleimide compound.

Examples of the structural unit derived from the maleimide compound include a group represented by the following general formula (1-1), a group represented by the following general formula (1-2), and the like.

In the general formulas (1-1) and (1-2), A ¹ indicates a residue of a maleimide compound, and * indicates a binding portion.
The residue refers to the structure of a portion of the raw material component excluding the functional group (maleimide group in the case of a maleimide compound) provided for bonding.

The ^{residue represented by A 1} is preferably a divalent group represented by the following general formulas (2), (3), (4) or (5).

（式中、Ｒ^１は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基、又はハロゲン原子を示す。）

(In the formula, R ¹ independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom.)

（式中、Ｒ^２及びＲ^３は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基又はハロゲン原子を示し、Ａ^２は炭素数１〜５のアルキレン基若しくはアルキリデン基、エーテル基、スルフィド基、スルフォニル基、カルボオキシ基、ケトン基、単結合又は下記一般式（３−１）で表される基である。）

(In the formula, R ² and R ³ independently represent a hydrogen atom, an aliphatic hydrocarbon group ^{having 1 to 5 carbon atoms or a halogen atom, and A 2} is an alkylene group or an alkylidene group having 1 to 5 carbon atoms and an ether. A group, a sulfide group, a sulfonyl group, a carbooxy group, a ketone group, a single bond or a group represented by the following general formula (3-1).)

（式中、Ｒ^４及びＲ^５は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基又はハロゲン原子を示し、Ａ^３は炭素数１〜５のアルキレン基、イソプロピリデン基、エーテル基、スルフィド基、スルフォニル基、カルボオキシ基、ケトン基又は単結合である。）

(In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom, an aliphatic hydrocarbon group ^{having 1 to 5 carbon atoms or a halogen atom, and A 3} is an alkylene group having 1 to 5 carbon atoms and an isopropylidene group. It is an ether group, a sulfide group, a sulfonyl group, a carbooxy group, a ketone group or a single bond.)

（式中、ｉは１〜１０の整数である。）

(In the formula, i is an integer from 1 to 10.)

（式中、Ｒ^６及びＲ^７は各々独立に、水素原子又は炭素数１〜５の脂肪族炭化水素基を示し、ｊは１〜８の整数である。）

(In the formula, R ⁶ and R ⁷ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and j is an integer of 1 to 8.)

R ^{1 in} the general formula ( ² ), R 2 and R ^{3 in the general formula (3), R 4} and R ⁵ in the general formula (3-1) ^{, R 6} and R ^{7 in the} general formula (5). Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms shown in the above include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group and the like. Can be mentioned. The aliphatic hydrocarbon group may be an aliphatic hydrocarbon group having 1 to 3 carbon atoms or a methyl group.
The general formula (3) A ² and general formula (3-1) alkylene group of 1 to 5 carbon atoms represented by A ³ in in, methylene group, ethylene group, propylene group, butylene group, pentylene group and the like Can be mentioned.
^{Examples of the alkylidene group having 1 to 5 carbon atoms represented by A 2} in the general formula (3) include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, and a pentylidene group.

The diamine compound is not particularly limited as long as it is a compound having two amino groups.
Examples of the diamine compound include 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 4,4'-. Diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylketone, 4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′- Diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis (3-amino-4-hydroxyphenyl) propane, 3,3'-dimethyl- 5,5'-diethyl-4,4'-diphenylmethanediamine, 2,2-bis (4-aminophenyl) propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3- Bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 1 , 3-bis {1- [4- (4-aminophenoxy) phenyl] -1-methylethyl} benzene, 1,4-bis {1- [4- (4-aminophenoxy) phenyl] -1-methylethyl } Benzene, 4,4'-[1,3-Phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,4-Phenylenebis (1-methylethylidene)] bisaniline, 3,3'- [1,3-phenylenebis (1-methylethylidene)] bisaniline, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 9,9-bis ( 4-Aminophenyl) Fluolene and the like can be mentioned. These may be used alone or in combination of two or more.
Among these, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4', from the viewpoint of solubility in organic solvents, reactivity during synthesis and heat resistance. -Diamino-3,3'-diethyldiphenylmethane, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisaniline and 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline is preferred. The diamine compound is preferably 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane from the viewpoint of dielectric properties and low water absorption. Further, from the viewpoint of high adhesiveness to the conductor and mechanical properties, 2,2-bis [4- (4-aminophenoxy) phenyl] propane is preferable. Furthermore, from the viewpoints of solubility in organic solvents, reactivity during synthesis, heat resistance, high adhesion to conductors, and excellent high frequency characteristics and low hygroscopicity, 4,4'-[1 , 3-Phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline is preferred, and 4,4'-[1,3-phenylenebis (1,3-phenylenebis) 1-Methylethylidene)] Bisaniline is more preferred.

The content of the structural unit derived from the diamine compound in the polyimide compound (a1) is preferably 2 to 30% by mass, more preferably 5 to 20% by mass, still more preferably 5 to 15% by mass in terms of the amount charged. By setting the content of the structural unit of the diamine compound within the above range, better high frequency characteristics, heat resistance, flame retardancy, and glass transition temperature tend to be obtained.

Examples of the structural unit derived from the diamine compound include a group represented by the following general formula (6-1), a group represented by the following general formula (6-2), and the like.

In the general formula (6-1) and (6-2), ^{A 4} represents a residue of a diamine compound, * represents a bonding unit.

The residue A ⁴ is shown, is preferably a divalent group represented by the following general formula (7).

（式中、Ｒ^８及びＲ^９は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基、炭素数１〜５のアルコキシ基、水酸基又はハロゲン原子を示し、Ａ^５は炭素数１〜５のアルキレン基若しくはアルキリデン基、エーテル基、スルフィド基、スルフォニル基、カルボオキシ基、ケトン基、フルオレニレン基、単結合、下記一般式（７−１）又は下記一般式（７−２）で表される基である。）

(In the formula, R ⁸ and R ⁹ independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group or a halogen atom, and A ⁵ has a carbon number of carbon atoms. 1 to 5 alkylene group or alkylidene group, ether group, sulfide group, sulfonyl group, carbooxy group, ketone group, fluorenylene group, single bond, represented by the following general formula (7-1) or the following general formula (7-2) It is the group to be done.)

（式中、Ｒ^１０及びＲ^１１は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基又はハロゲン原子を示し、Ａ^６は炭素数１〜５のアルキレン基、イソプロピリデン基、ｍ−又はｐ−フェニレンジイソプロピリデン基、エーテル基、スルフィド基、スルフォニル基、カルボオキシ基、ケトン基又は単結合である。）

(In the formula, R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an aliphatic hydrocarbon group ^{having 1 to 5 carbon atoms or a halogen atom, and A 6} is an alkylene group having 1 to 5 carbon atoms and an isopropylidene group. m- or p-phenylenediisopropylidene group, ether group, sulfide group, sulfonyl group, carbooxy group, ketone group or single bond)

（式中、Ｒ^１２は各々独立に、水素原子、炭素数１〜５の脂肪族炭化水素基又はハロゲン原子を示し、Ａ^７及びＡ^８は炭素数１〜５のアルキレン基、イソプロピリデン基、エーテル基、スルフィド基、スルフォニル基、カルボオキシ基、ケトン基又は単結合である。）

(In the formula, R ¹² independently represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom, and A ⁷ and A ⁸ are an alkylene group having 1 to 5 carbon atoms and an isopropylidene group. It is an ether group, a sulfide group, a sulfonyl group, a carbooxy group, a ketone group or a single bond.)

Aliphatic hydrocarbons having 1 to 5 carbon atoms represented by R ⁸ and R ^{9 in} the general formula (7), R ¹⁰ and R ^{11 in} the general formula (7-1), and R ^{12 in the general formula (7-2).} The hydrogen group is described in the same manner as the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by ^{R 1} in the general formula (2).
The alkylene groups having 1 to 5 carbon atoms represented by A ^{5 in} the general formula (7), A ^{6 in} the general formula (7-1), and A ⁷ and A ^{8 in the general formula (7-2) are described above.} It will be described in the same manner as the alkylene group having 1 to 5 carbon atoms represented by ^{A 2} in the general formula (3).
The alkylidene group having 1 to 5 carbon atoms represented by A ⁵ in formula (7), is described as with an alkylidene group having 1 to 5 carbon atoms A ² represents in the general formula (3).

The polyimide compound (a1) contains a polyaminobismaleimide compound represented by the following general formula (8) from the viewpoints of solubility in an organic solvent, high frequency characteristics, high adhesiveness to a conductor, moldability of a film, and the like. Is preferable.

（式中、Ａ^９は前記一般式（１−１）のＡ^１と同様に説明され、Ａ^１０は前記一般式（６−１）のＡ^４と同様に説明される。）

(In the formula, A ⁹ is described in the same manner as ^{A 1 in the} general formula (1-1) ^{, and A 10} is described in the same manner as ^{A 4 in the} general formula (6-1).)

(Method for producing polyimide compound (a1))
The polyimide compound (a1) can be produced, for example, by reacting a maleimide compound and a diamine compound in an organic solvent.
The organic solvent used for producing the polyimide compound (a1) is not particularly limited, and a known solvent can be used. The organic solvent is not particularly limited, but for example, alcohols such as methanol, ethanol, butanol, butyl cellosolve, ethylene glycol monomethyl ether and propylene glycol monomethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; toluene, xylene, etc. Aromatic hydrocarbons such as mesitylene; esters such as methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate; amides such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone. Examples include system solvents. These may be used alone or in combination of two or more. Among these, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, N, N-dimethylformamide, and N, N-dimethylacetamide are preferable from the viewpoint of solubility.

The amount of the maleimide compound and the diamine compound used in producing the polyimide compound (a1 _{) is the equivalent ratio (Ta2 / Ta1) of the -NH 2} group equivalent (Ta2) of the diamine compound and the maleimide group equivalent (Ta1) of the maleimide compound. ) Is preferably 0.05 to 10.0, more preferably 0.05 to 1.0, and even more preferably 0.1 to 0.8. By reacting the maleimide compound with the diamine compound within the above range, better high frequency characteristics, heat resistance, flame retardancy, and glass transition temperature tend to be obtained.

When the polyimide compound (a1) is produced by reacting the maleimide compound with the diamine compound, a reaction catalyst can be used as needed. The reaction catalyst is not limited, for example, an acidic catalyst such as p-toluenesulfonic acid; amines such as triethylamine, pyridine and tributylamine; imidazoles such as methylimidazole and phenylimidazole; and a phosphorus catalyst such as triphenylphosphine. And so on. These may be used alone or in combination of two or more. The amount of the reaction catalyst to be blended is not particularly limited, but for example, it can be used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the total amount of the maleimide compound and the diamine compound.

A polyimide compound (a1) is obtained by charging a predetermined amount of a maleimide compound, a diamine compound, an organic solvent and, if necessary, a reaction catalyst and the like into a synthesis pot and causing a Michael addition reaction. The reaction conditions in this step are not particularly limited, but from the viewpoint of workability such as reaction rate and suppression of gelation, for example, the reaction temperature is preferably 50 to 160 ° C. and the reaction time is preferably 1 to 10 hours. ..
Further, in this step, the above-mentioned organic solvent may be added or concentrated to adjust the solid content concentration and solution viscosity of the reaction raw material. The solid content concentration of the reaction raw material is not particularly limited, but is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, for example. When the solid content concentration of the reaction raw material is 10% by mass or more, the reaction rate does not become too slow, which is advantageous in terms of production cost. Further, when the solid content concentration of the reaction raw material is 90% by mass or less, good solubility is obtained, stirring efficiency is good, and gelation is less likely to occur.
After the production of the polyimide compound (a1), a part or all of the organic solvent may be removed and concentrated according to the purpose, or the organic solvent may be added and diluted. As the organic solvent additionally used, the organic solvent exemplified in the description of the method for producing the polyimide compound (a1) can be applied.

The weight average molecular weight (Mw) of the polyimide compound (a1) is not particularly limited, but is, for example, preferably 800 to 10,000, more preferably 800 to 8,000, still more preferably 800 to 5,000, and 1,000. ~ 5,000 is particularly preferable, and 1,500 to 4,000 is most preferable. The weight average molecular weight of the polyimide compound (a1) can be determined by the method described in Examples.

(Content of polyimide compound (a1))
The content of the polyimide compound (a1) in the resin composition is not particularly limited, but is preferably 40 to 95% by mass, more preferably 60 to 95% by mass, based on the total resin components contained in the resin composition. 65 to 85% by mass is more preferable. By setting the content of the polyimide compound (a1) within the above range, insulation reliability is excellent, a low coefficient of thermal expansion, a high glass transition temperature, and a good dielectric loss tangent tend to be obtained.

<Inorganic filler (a2)>
The inorganic filler (a2) is not particularly limited, but for example, silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, etc. Examples thereof include aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate and the like. These may be used alone or in combination of two or more. Among these, silica is preferable from the viewpoint of lower thermal expansion.

The shape of the inorganic filler (a2) is not particularly limited and may be, for example, spherical, crushed, needle-shaped or plate-shaped, but the dispersibility in the resin composition is improved, and the resin composition is used as an organic solvent. It should be spherical from the viewpoints of improving dispersibility in the resin varnish in which the resin varnish is dissolved or dispersed, improving the fluidity by reducing the viscosity of the resin varnish, and suppressing the increase in the surface roughness of the insulating layer formed from the resin composition. preferable.

The volume average particle diameter of the inorganic filler (a2) is not particularly limited, but is preferably, for example, 0.05 to 5 μm, more preferably 0.1 to 3 μm, and even more preferably 0.2 to 1 μm. When the volume average particle diameter of the component (a2) is 5 μm or less, the fine pattern tends to be formed more stably when the circuit pattern is formed on the interlayer insulating layer. Further, when the volume average particle diameter of the inorganic filler (a2) is 0.1 μm or more, the heat resistance tends to be better.
The volume average particle size is the particle size of a point corresponding to 50% of the volume when the cumulative frequency distribution curve based on the particle size is obtained with the total volume of the particles as 100%. It can be measured with the particle size distribution measuring device or the like used.

Further, for the purpose of improving the dispersibility of the inorganic filler (a2) and the adhesiveness between the inorganic filler (a2) and the organic component in the resin composition, a coupling agent may be used in combination, if necessary. The coupling agent is not particularly limited, and for example, various silane coupling agents, titanate coupling agents, and the like can be used. These may be used alone or in combination of two or more. Among these, a silane coupling agent is preferable. Examples of the silane coupling agent include aminosilane-based coupling agents, epoxysilane-based coupling agents, phenylsilane-based coupling agents, alkylsilane-based coupling agents, alkenylsilane-based coupling agents, and mercaptosilane-based coupling agents. Be done. Among these, an aminosilane-based coupling agent is preferable from the viewpoint of improving the dispersibility of the inorganic filler (a2) and improving the adhesiveness between the inorganic filler (a2) and the organic component.
When a coupling agent is used, the amount used is not particularly limited, but is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the inorganic filler (a2). preferable. Within this range, the features of using the inorganic filler (a2) can be exhibited more effectively.
When a coupling agent is used, the addition method may be a so-called integral blend treatment method in which the inorganic filler (a2) is added to the resin composition and then the coupling agent is added, which is more effective. From the viewpoint of demonstrating the characteristics of the inorganic filler (a2), a method may be used in which the coupling agent is surface-treated in advance with respect to the inorganic filler before compounding by a dry method or a wet method.

The inorganic filler (a2) is preferably used in the state of a slurry previously dispersed in an organic solvent from the viewpoint of enhancing dispersibility in the resin composition. The organic solvent used in the slurry of the inorganic filler (a2) is not particularly limited, and for example, the organic solvent exemplified in the above-mentioned production step of the polyimide compound (a1) can be applied. These may be used alone or in combination of two or more. Among these organic solvents, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are preferable from the viewpoint of further enhancing dispersibility.
The solid content concentration of the slurry of the inorganic filler (a2) is not particularly limited, but for example, from the viewpoint of sedimentation and dispersibility of the inorganic filler (a2), 50 to 80% by mass is preferable, and 60 to 80% by mass is preferable. Is more preferable.
The content of the inorganic filler (a2) can be appropriately selected depending on the desired properties and functions, but is preferably 55% by volume or more, more preferably 55 to 85% by volume, and 55 to 80% by volume, based on the solid content of the resin composition. By volume% is more preferred, and 55-75% by volume is particularly preferred. By setting the content of the inorganic filler in such a range, it is possible to have a low coefficient of thermal expansion.
In the present specification, the solid content contained in the resin composition means a residue obtained by excluding volatile components from the components constituting the resin composition.

<Elastomer (a3)>
The resin composition for the A layer may contain an elastomer (a3). The elastomer (a3) is not particularly limited, and for example, a polybutadiene-based elastomer, a styrene-based elastomer, an olefin-based elastomer, a urethane-based elastomer, a polyester-based elastomer, a polyamide-based elastomer, an acrylic-based elastomer, a silicone-based elastomer, and these elastomers. Derivatives and the like can be mentioned. These may be used alone or in combination of two or more.

As the elastomer (a3), one having a reactive functional group at the molecular terminal or in the molecular chain can be used. The reactive functional group is, for example, one or more selected from the group consisting of a maleic anhydride group, an epoxy group, a hydroxyl group, a carboxy group, an amino group, an amide group, an isocyanato group, an acrylic group, a methacryl group and a vinyl group. It is more preferable that there is at least one selected from the group consisting of a maleic anhydride group, an epoxy group, a hydroxyl group, a carboxy group, an amino group and an amide group from the viewpoint of adhesion to a metal foil. From the viewpoint of dielectric properties, a maleic anhydride group is more preferable. By having these reactive functional groups, the compatibility with the resin is improved, and the separation between the inorganic filler (a2) and the resin component when the interlayer insulating layer is formed tends to be suppressed. From the same viewpoint, the elastomer (a3) is preferably an elastomer modified with maleic anhydride.

The polybutadiene-based elastomer preferably includes a structure consisting of a 1,4-trans form and a 1,4-cis form containing a 1,2-vinyl group.
As the polybutadiene-based elastomer, those having a reactive functional group are used from the viewpoint of improving the compatibility with the resin and suppressing the separation between the inorganic filler (a2) and the resin component when the interlayer insulating layer is formed. Preferably, a polybutadiene-based elastomer modified with an acid anhydride is particularly preferable. The acid anhydride is not particularly limited, and for example, phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, nadicic anhydride, Phthalic anhydride, dimethylglutaric anhydride, diethylglutaric anhydride, succinic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride and the like can be mentioned. Of these, maleic anhydride is preferred.
When the elastoma (a3) is modified with an acid anhydride, the number of acid anhydride-derived groups (hereinafter, also referred to as "acid anhydride groups") contained in one molecule of the elastoma (a3) is 1 to 10. Is preferable, 1 to 6 are more preferable, and 2 to 5 are even more preferable. When the number of acid anhydride groups is 1 or more in one molecule, the separation between the inorganic filler (a2) and the resin component when the interlayer insulating layer is formed tends to be further suppressed. Further, when the number of acid anhydride groups is 10 or less in one molecule, the dielectric loss tangent of the resin composition tends to be lower. When the elastomer (a3) is modified with maleic anhydride, a group derived from maleic anhydride contained in one molecule of the elastomer (a3) (hereinafter, also referred to as "maleic anhydride group") from the same viewpoint as above. The number of is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 to 5.
Polybutadiene-based elastomers are available as commercial products, and specific examples thereof include, for example, "POLYVEST (registered trademark) MA75", "POLYVEST (registered trademark) EP MA120" (all manufactured by Ebonic, trade name), and the like. Examples thereof include "Ricon (registered trademark) 130MA8", "Ricon (registered trademark) 131MA5", and "Ricon (registered trademark) 184MA6" (all manufactured by Clay Valley Co., Ltd., trade name).

Preferable examples of the styrene-based elastoma include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, and styrene-ethylene-propylene-styrene block copolymer. Examples of the components constituting the styrene-based elastomer include styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene, in addition to styrene. Styrene-based elastoma is available as a commercial product, and specific examples thereof include "Toughprene (registered trademark)", "Asaprene (registered trademark) T", "Toughtech (registered trademark) H", and "Toughtech (registered trademark)". ) MP10 ”,“ Tough Tech (registered trademark) M1911 ”,“ Tough Tech (registered trademark) M1913 ”(above, manufactured by Asahi Kasei Chemicals Co., Ltd.),“ Epofriend (registered trademark) AT501 ”,“ Epofriend (registered trademark) CT310 ” (The above is manufactured by Daicel Co., Ltd.) and the like.

Examples of the olefin-based elastoma include copolymers of α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-hexene and 4-methyl-pentene, and examples thereof include ethylene-propylene. Preferable examples thereof include a polymer (EPR) and an ethylene-propylene-diene copolymer (EPDM). Examples thereof include a copolymer of the α-olefin with a non-conjugated diene having 2 to 20 carbon atoms such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene, etylidenenorbornene, butadiene, and isoprene. .. Further, carboxy-modified NBR obtained by copolymerizing methacrylic acid with a butadiene-acnillonitrile copolymer can be mentioned. Olefin-based elastomers are available as commercial products, and specific examples thereof include "PB3600", "PB4700" (all manufactured by Daicel Corporation), "G-1000", "G-2000", and "G-". 3000 ”,“ JP-100 ”,“ JP-100 ”,“ BN-1015 ”,“ TP-1001 ”,“ TEA-1000 ”,“ EA-3000 ”,“ TE-2000 ”,“ EMA-3000 ” (The above is manufactured by Nippon Soda Co., Ltd.), "Denalex (registered trademark) R45" (manufactured by Nagase ChemteX Corporation), and the like.

The urethane-based elastomer preferably contains, for example, a hard segment composed of a short-chain diol and a diisocyanate, and a soft segment composed of a polymer (long-chain) diol and a diisocyanate.
Examples of the polymer (long chain) diol include polypropylene glycol, polytetramethylene oxide, poly (1,4-butylene adipate), poly (ethylene-1,4-butylene adipate), polycaprolactone, and poly (1,6-he). Xylene carbonate), poly (1,6-hexylene / neopentylene adipate) and the like. The number average molecular weight of the polymer (long chain) diol is preferably 500 to 10,000.
Examples of the short chain diol include ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A. The number average molecular weight of the short chain diol is preferably 48 to 500.
Urethane-based elastomers are available as commercial products, and specific examples thereof include "PANDEX (registered trademark) T-2185" and "PANDEX (registered trademark) T-2983N" (all manufactured by DIC Corporation). Can be mentioned.

Examples of the polyester-based elastomer include those obtained by polycondensing a dicarboxylic acid or a derivative thereof and a diol compound or a derivative thereof.
Specific examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and aromatic dicarboxylic acids in which the hydrogen atom of these aromatic nuclei is substituted with a methyl group, an ethyl group, a phenyl group, or the like; Examples thereof include aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid and dodecanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. One of these compounds may be used alone, or two or more of these compounds may be used in combination.
Specific examples of the diol compound include aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol; 1,4-cyclohexanediol. Aliphatic diols such as bisphenol A, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) propane, aromatic diols such as resorcin and the like. One of these compounds may be used alone, or two or more of these compounds may be used in combination.

Further, as the polyester-based elastomer, a multi-block copolymer having an aromatic polyester (for example, polybutylene terephthalate) portion as a hard segment component and an aliphatic polyester (for example, polytetramethylene glycol) portion as a soft segment component is preferable. Can be mentioned. There are various grades of multi-block copolymers depending on the types, ratios, and molecular weights of hard segments and soft segments. Specific examples thereof include "Hitrel (registered trademark)" (Dupont Toray Industries, Inc.), "Perprene (registered trademark)" (Toyo Spinning Co., Ltd.), and "Esper (registered trademark)" (Hitachi Kasei Co., Ltd.). ) Etc. can be mentioned.

As the polyamide-based elastoma, for example, polyamide is a hard segment component, polybutadiene, butadiene-acrylonitrile copolymer, styrene-butadiene copolymer, polyisoprene, ethylene propylene copolymer, polyether, polyester, polybutadiene, polycarbonate, polyacrylate. , Polymethacrylate, polyurethane, silicone rubber and the like as soft segment components.
Polyamide-based elastoma is available as a commercial product, and specific examples thereof include "UBE Polyamide Elastoma" (manufactured by Ube Industries, Ltd.), "Diamid (registered trademark)" (manufactured by Dicelle Evonik Corporation), and "PEBAX". (Registered Trademark) ”(Toray Industries, Inc.),“ Grillon (Registered Trademark) ELY ”(M.Schemy Japan Co., Ltd.),“ Novamid (Registered Trademark) ”(Mitsubishi Chemical Co., Ltd.) ) ”(Manufactured by DIC Corporation),“ BPAM-01 ”,“ BPAM-155 ”(all manufactured by Nippon Kayaku Co., Ltd.) and the like.

Examples of the acrylic elastomer include a polymer of a raw material monomer containing an acrylic ester as a main component. Preferable examples of the acrylic acid ester include ethyl acrylate, butyl acrylate, methoxyethyl acrylate, and ethoxyethyl acrylate. Further, as the cross-linking point monomer, glycidyl methacrylate, allyl glycidyl ether and the like may be copolymerized, and further, acrylonitrile, ethylene and the like may be copolymerized. Specific examples thereof include an acrylonitrile-butyl acrylate copolymer, an acrylonitrile-butyl acrylate-ethyl acrylate copolymer, and an acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer.

Silicone-based elastomers are elastomers containing organopolysiloxane as a main component, and are classified into, for example, polydimethylsiloxane-based, polymethylphenylsiloxane-based, polydiphenylsiloxane-based, and the like. Silicone-based elastomers are available as commercial products, and specific examples thereof include "X-22-163B", "X-22-163C", "X-22-1821", and "X-22-162C". (Above, manufactured by Shin-Etsu Chemical Co., Ltd.), Core-shell type silicone rubber "SY series" (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.), "SE series", "CY series", "SH series" (above, Toray Dow Corning Co., Ltd.) (Made by company), etc.

Among these elastomers, styrene-based elastomers, polybutadiene-based elastomers, olefin-based elastomers, polyamide-based elastomers, and silicone-based elastomers are preferable from the viewpoint of heat resistance and insulation reliability, and polybutadiene-based elastomers and styrene-based elastomers are preferable from the viewpoint of dielectric properties. Elastomers are more preferred, and polybutadiene-based elastomers are even more preferred.

The weight average molecular weight of the elastomer (a3) is preferably 500 to 50,000, more preferably 1,000 to 30,000. When the weight average molecular weight of the elastomer (a3) is 500 or more, the curability of the resin composition and the dielectric properties of the cured product tend to be better. Further, when the weight average molecular weight of the elastomer (a3) is 50,000 or less, the separation of the inorganic filler (a2) and the resin component when the interlayer insulating layer is formed tends to be suppressed. As the weight average molecular weight of the elastomer (a3), the method for measuring the weight average molecular weight of the polyimide compound (a1) described in Examples can be applied.

When the resin composition contains an elastomer (a3), the content thereof is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, and 10 to 30% by mass, based on the total resin components contained in the resin composition. Mass% is more preferred. By setting the content of the elastomer (a3) within the above range, the dielectric loss tangent is low, the handleability when formed into a film is excellent, and the inorganic filler (a2) and the resin component when the interlayer insulating layer is formed Separation tends to be suppressed.

<Other ingredients>
The resin composition for the A layer may contain a flame retardant, a curing accelerator, or the like, if necessary.
By including a flame retardant in the resin composition, better flame retardancy can be imparted. The flame retardant is not particularly limited, and examples thereof include a chlorine-based flame retardant, a bromine-based flame retardant, a phosphorus-based flame retardant, and a metal hydrate-based flame retardant. Phosphorus-based flame retardants and metal hydrate-based flame retardants are preferable from the viewpoint of compatibility with the environment.
Further, by incorporating an appropriate curing accelerator into the resin composition, the curability of the resin composition can be improved, and the dielectric properties, heat resistance, high elastic modulus, glass transition temperature and the like can be further improved. The curing accelerator is not particularly limited, and examples thereof include various imidazole compounds and derivatives thereof; various tertiary amine compounds; various quaternary ammonium compounds; and various phosphorus compounds such as triphenylphosphine.
The resin composition may also contain additives such as an antioxidant and a flow conditioner.

(Resin varnish)
In the production of the A layer, it is preferable that the resin composition for the A layer further contains an organic solvent to prepare a resin varnish (hereinafter, also referred to as a varnish for the A layer).
Examples of the organic solvent used for producing the varnish for layer A include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; and acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate and carbitol acetate; cellosolve, (Di) ethylene glycol monoalkyl ether or propylene glycol monoalkyl ether such as butyl carbitol and propylene glycol monomethyl ether; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone and the like. Examples thereof include amide-based solvents. These may be used alone or in combination of two or more.
The content of the organic solvent is preferably 10 to 60 parts by mass, more preferably 10 to 35 parts by mass with respect to 100 parts by mass of the entire varnish for layer A.
By using the varnish for layer A produced in this manner, the composite film of the present invention can be produced as described above.

[Component of layer B]
Examples of the component of the B layer include a resin composition. The resin composition is not particularly limited as long as it improves the adhesiveness with the conductor layer, but for example, a polyfunctional epoxy resin from the viewpoint of excellent adhesiveness with plated copper even if the surface roughness is small. A resin composition containing (b1) and a phenolic hydroxyl group-containing polybutadiene-modified polyamide resin (b2) is preferable, and a resin composition containing an active ester curing agent (b3) is more preferable. Hereinafter, each component will be described in detail.

<Multifunctional epoxy resin (b1)>
The polyfunctional epoxy resin (b1) is not particularly limited as long as it is a resin having two or more epoxy groups, and for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, and a cresol novolac type epoxy. Resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, aralkylnovolac type epoxy resin, fluorene type epoxy resin, xantene type epoxy resin And so on. From the viewpoint of adhesiveness to plated copper, it is preferable to have a biphenyl structure, and a polyfunctional epoxy resin having a biphenyl structure or an aralkyl novolac type epoxy resin having a biphenyl structure is more preferable.
As the polyfunctional epoxy resin (b1), one type may be used alone, or two or more types may be used in combination.

As the polyfunctional epoxy resin (b1), a commercially available product may be used. Commercially available polyfunctional epoxy resins (b1) include "NC-3000-H", "NC-3000-L", and "NC" manufactured by Nippon Kayaku Co., Ltd., which are aralkyl novolac type epoxy resins having a biphenyl structure. -3100 ”,“ NC-3000 ”and the like.

The epoxy equivalent of the polyfunctional epoxy resin (b1) is not particularly limited, but is preferably 150 to 450 g / mol, more preferably 200 to 400 g / mol, and even more preferably 250 to 350 g / mol from the viewpoint of adhesiveness.

The content of the polyfunctional epoxy resin (b1) in the resin composition for the B layer is not particularly limited, but is preferably 10 to 90% by mass, preferably 20 to 80% by mass, based on the total resin components contained in the resin composition. The mass% is more preferable, and 30 to 70% by mass is further preferable. When the content of the polyfunctional epoxy resin (b1) is 10% by mass or more, better adhesive strength with plated copper tends to be obtained, and when it is 90% by mass or less, lower dielectric loss tangent is obtained. Tends to be.

<Phenolic hydroxyl group-containing polybutadiene-modified polyamide resin (b2)>
The component (b2) is not particularly limited as long as it is a polybutadiene-modified polyamide resin having a phenolic hydroxyl group, but is a diamine-derived structural unit, a dicarboxylic acid-derived structural unit containing a phenolic hydroxyl group, and a phenolic property. Those having a structural unit derived from a dicarboxylic acid that does not contain a hydroxyl group and a structural unit derived from polybutadiene having a carboxy group at both ends are preferable. Specifically, those having a structural unit represented by the following general formula (i), a structural unit represented by the following general formula (ii), and a structural unit represented by the following general formula (iii) are preferably mentioned. ..

In the general formulas (i) to (iii), a, b, c, x, y and z are integers indicating the average degree of polymerization, respectively, and a = 2 to 10, b = 0 to 3, c = 3. ~ 30, y + z = 2 to 300 ((y + z) / x) for x = 1, and z ≧ 20 (z / y) for y = 1.
In the general formulas (i) to (iii), R'independently represents a divalent group derived from an aromatic diamine or an aliphatic diamine, and in the general formula (iii), R'' is an aromatic dicarboxylic acid. , An aliphatic dicarboxylic acid or a divalent group derived from an oligomer having a carboxy group at both ends.
The plurality of R'included in the general formulas (i) to (iii) may be the same or different. Further, when z is an integer of 2 or more, a plurality of R''s may be the same or different.
In the general formulas (i) to (iii), R'is specifically a divalent group derived from an aromatic diamine or an aliphatic diamine described later, and R'' is an aromatic group described later. It is preferably a divalent group derived from a dicarboxylic acid, an aliphatic dicarboxylic acid or an oligomer having a carboxy group at both ends.

Examples of the diamine used for forming the structural unit derived from diamine in the component (b2) include aromatic diamines and aliphatic diamines.
Examples of the aromatic diamine include diaminobenzene, diaminotoluene, diaminophenol, diaminodimethylbenzene, diaminomethicylene, diaminonitrobenzene, diaminodiazobenzene, diaminonaphthalene, diaminobiphenyl, diaminodimethoxybiphenyl, diaminodiphenyl ether, diaminodimethyldiphenyl ether, and methylene. Diamine, methylenebis (dimethylaniline), methylenebis (methoxyaniline), methylenebis (dimethoxyaniline), methylenebis (ethylaniline), methylenebis (diethylaniline), methylenebis (ethoxyaniline), methylenebis (diethoxyaniline), isopropyridene dianiline, Examples thereof include diaminobenzophenone, diaminodimethylbenzophenone, diaminoanthraquinone, diaminodiphenylthioether, diaminodimethyldiphenylthioether, diaminodiphenylsulfone, diaminodiphenylsulfoxide and diaminofluorene.

Examples of the aliphatic diamine include ethylenediamine, propanediamine, hydroxypropanediamine, butanediamine, heptanediamine, hexanediamine, cyclopentanediamine, cyclohexanediamine, azapentanediamine, triazaundecadiamine and the like.

Examples of the phenolic hydroxyl group-containing dicarboxylic acid used to form the “structural unit derived from the phenolic hydroxyl group-containing dicarboxylic acid” of the component (b2) include hydroxyisophthalic acid, hydroxyphthalic acid, and hydroxyterephthalic acid. Acids, dihydroxyisophthalic acid, dihydroxyterephthalic acid and the like can be mentioned.
Examples of the phenolic hydroxyl acid-free dicarboxylic acid used to form the "structural unit derived from a phenolic hydroxyl acid-free dicarboxylic acid" contained in the component (b2) include aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Examples thereof include oligomers having a carboxy group at both ends.
Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, biphenyldicarboxylic acid, methylenedibenzoic acid, thiodibenzoic acid, carbonyldibenzoic acid, sulfonylbenzoic acid, naphthalenedicarboxylic acid and the like.
Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, methylmalonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, malic acid, tartaric acid, (meth) acryloyloxysuccinic acid, and di (meth). ) Acryloyloxysuccinic acid, (meth) acryloyloxymalic acid, (meth) acrylamide succinic acid, (meth) acrylamide malic acid and the like can be mentioned.

The weight average molecular weight of the component (b2) is not particularly limited, but is preferably, for example, 60,000 to 250,000, and more preferably 80,000 to 200,000. The weight average molecular weight of the component (b2) can be determined by the same method as the weight average molecular weight of the polyimide compound (a1).

The active hydroxyl group equivalent of the component (b2) is not particularly limited, but is preferably 1,500 to 7,000 g / mol, more preferably 2,000 to 6,000 g / mol, and 3,000 to 5,000 g / mol. Is even more preferable.

The component (b2) contains, for example, a diamine, a dicarboxylic acid containing a phenolic hydroxyl group, a dicarboxylic acid not containing a phenolic hydroxyl group, and polybutadiene having a carboxy group at both ends in an organic solvent such as dimethylacetamide. , It is synthesized by reacting a carboxylic acid ester as a catalyst in the presence of a pyridine derivative and polycondensing a carboxy group and an amino group. Examples of each compound that can be used in the production include those described above.

The polybutadiene having a carboxy group at both ends used for producing the component (b2) is preferably an oligomer having a number average molecular weight of 200 to 10,000, and a number average molecular weight of 500 to 5,000, for example. Is more preferable.

As the component (b2), a commercially available product can be used, and examples of the component (b2) of the commercially available product include "BPAM-155" manufactured by Nippon Kayaku Co., Ltd.

The content of the component (b2) in the resin composition for the B layer is not particularly limited, but is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, based on the total resin components contained in the resin composition. It is preferable, and 3 to 10% by mass is more preferable. When the content of the component (b2) is 1% by mass or more, the toughness of the resin composition can be increased, a fine roughened shape can be obtained, and the adhesiveness with the plated copper can be enhanced. .. Further, when it is 20% by mass or less, the heat resistance does not decrease, and the decrease in resistance to the chemical solution during the roughening step can be prevented. In addition, sufficient adhesiveness with plated copper can be ensured.

<Active ester curing agent (b3)>
The active ester curing agent (b3) has one or more ester groups in one molecule and has a curing action of an epoxy resin.
The active ester curing agent (b3) is not particularly limited, and examples thereof include an ester compound obtained from an aliphatic or aromatic carboxylic acid and an aliphatic or aromatic hydroxy compound.
Among these, ester compounds obtained from aliphatic carboxylic acids, aliphatic hydroxy compounds and the like tend to be soluble in organic solvents and highly compatible with epoxy resins by containing aliphatic chains.
Further, an ester compound obtained from an aromatic carboxylic acid, an aromatic hydroxy compound or the like tends to have an aromatic ring to enhance heat resistance.

Examples of the active ester curing agent (b3) include phenol ester compounds, thiophenol ester compounds, N-hydroxyamine ester compounds, and esterified compounds of heterocyclic hydroxy compounds.
More specifically, for example, an aromatic ester obtained by a condensation reaction of an aromatic carboxylic acid and a phenolic hydroxyl group can be mentioned, and aromatics such as benzene, naphthalene, biphenyl, diphenylpropane, diphenylmethane, diphenyl ether, and diphenyl sulfonic acid can be mentioned. An aromatic carboxylic acid component selected from those in which 2 to 4 hydrogen atoms in the ring are substituted with a carboxy group, a monovalent phenol in which one of the hydrogen atoms in the aromatic ring is substituted with a hydroxyl group, and a hydrogen atom in the aromatic ring. Aromatic esters obtained by a condensation reaction between an aromatic carboxylic acid and a phenolic hydroxyl group are preferable, using a mixture of 2 to 4 of the above with a polyvalent phenol substituted with a hydroxyl group as a raw material. That is, an aromatic ester having a structural unit derived from the aromatic carboxylic acid component, a structural unit derived from the monovalent phenol, and a structural unit derived from the polyhydric phenol is preferable.

As the active ester curing agent (b3), a commercially available product may be used. Commercially available products of the active ester curing agent (b3) include, for example, "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" (DIC) as active ester compounds containing a dicyclopentadiene type diphenol structure. (Manufactured by Co., Ltd.), "EXB9416-70BK" (manufactured by DIC Co., Ltd.) as an active ester compound containing a naphthalene structure, "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester compound containing an acetylated product of phenol novolac, Examples of the active ester compound containing a benzoyl compound include "YLH1026" (manufactured by Mitsubishi Chemical Corporation).
As the active ester curing agent (b3), one type may be used alone, or two or more types may be used in combination.

The ester equivalent of the active ester curing agent (b3) is not particularly limited, but is preferably 150 to 400 g / mol, more preferably 170 to 300 g / mol, and even more preferably 200 to 250 g / mol.

The equivalent ratio (ester group / epoxy group) of the ester group of the active ester curing agent (b3) to the epoxy group of the polyfunctional epoxy resin (b1) in the resin composition is preferably 0.05 to 1.5, and is 0. .1 to 1.3 is more preferable, and 0.2 to 1.0 is even more preferable. When the equivalent ratio (ester group / epoxy group) is within the above range, the adhesive strength with the plated copper is further increased, and a lower dielectric loss tangent and a smooth surface can be obtained, which is preferable from the viewpoint of forming fine wiring. is there.

<Phosphorus-based curing accelerator (b4)>
The resin composition for the B layer preferably further contains a phosphorus-based curing accelerator (b4).
The phosphorus-based curing accelerator (b4) is not particularly limited as long as it contains a phosphorus atom and promotes the reaction between the polyfunctional epoxy resin (b1) and the active ester curing agent (b3). Can be done.
By containing the phosphorus-based curing accelerator (b4) in the resin composition, the curing reaction can be further sufficiently promoted. The reason for this is that by using a phosphorus-based curing accelerator (b4), the electron-attracting property of the carbonyl group in the active ester curing agent (b3) can be enhanced, which is more than that of the active ester curing agent (b3). It is presumed that this is because the reaction with the functional epoxy resin (b1) is promoted.
As described above, by containing the phosphorus-based curing accelerator (b4), the resin composition contains the polyfunctional epoxy resin (b1) and the active ester curing agent (b3) as compared with the case where other curing accelerators are used. Since the curing reaction proceeds even more sufficiently, it is considered that a low dielectric loss tangent can be obtained when combined with the first resin layer.

Examples of the phosphorus-based curing accelerator (b4) include triphenylphosphine, diphenyl (alkylphenyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkylalkoxyphenyl) phosphine, and tris (dialkylphenyl). ) Hosphine, tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxyphenyl) phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, trialkylphosphine, dialkylarylphosphine , Organic phosphine such as alkyldiarylphosphine; complex of organic phosphine and organic borons; adducts of tertiary phosphine and quinones. An adduct of tertiary phosphine and quinones is preferable from the viewpoint that the curing reaction proceeds more sufficiently and high adhesiveness to plated copper can be exhibited.
The tertiary phosphine is not particularly limited, and is, for example, tri-n-butylphosphine, dibutylphenylphosphine, butyldiphenylphosphine, ethyldiphenylphosphine, triphenylphosphine, tris (4-methylphenyl) phosphine, tris (4-methylphenyl) phosphine. Methoxyphenyl) phosphine and the like can be mentioned. Examples of quinones include o-benzoquinone, p-benzoquinone, diphenoquinone, 1,4-naphthoquinone, anthraquinone and the like. An adduct of tri-n-butylphosphine and p-benzoquinone is more preferable from the viewpoint of adhesiveness to plated copper, heat resistance and a smooth surface.

As a method for producing an adduct of a tertiary phosphine and a quinone, for example, both are stirred and mixed in a solvent in which the raw material tertiary phosphine and a quinone are dissolved, and the adduct is reacted and then isolated. The method of doing this can be mentioned. In this case, for example, tertiary phosphine and quinones are stirred in a solvent such as methyl isobutyl ketone, methyl ethyl ketone, and ketones such as acetone in a range of 20 to 80 ° C. for 1 to 12 hours. It is preferable to carry out an addition reaction.

As the phosphorus-based curing accelerator (b4), one type may be used alone, or two or more types may be used in combination. In addition, one or more curing accelerators other than the phosphorus-based curing accelerator (b4) may be used in combination.

The content of the phosphorus-based curing accelerator (b4) in the resin composition for the B layer is not particularly limited, but is preferably 0.1 to 20% by mass with respect to the total resin components contained in the resin composition, and is 0. .2 to 15% by mass is more preferable, and 0.4 to 10% by mass is further preferable. When the content of the phosphorus-based curing accelerator (b4) is 0.1% by mass or more, the curing reaction can be sufficiently advanced, and when it is 20% by mass or less, the homogeneity of the cured product can be maintained. ..

<Filler (b5)>
The resin composition for the B layer may contain a filler (b5). Examples of the filler (H) include an inorganic filler and an organic filler. Among these, an inorganic filler is preferable.
By containing the filler (b5), the scattering of the resin can be further reduced when the B layer is laser-processed.

The inorganic filler is not particularly limited, but for example, the same one as that exemplified as the inorganic filler (A) can be used.
The particle size of the inorganic filler is preferably small from the viewpoint of forming fine wiring on the B layer. From the same viewpoint, the specific surface area of the inorganic filler ^{is preferably 20 m 2} / g or more, and more preferably 50 m ² / g or more. There is no particular limitation on the upper limit of the specific surface area, from the viewpoint of easy availability, preferably 500 meters ² / g or less, 200 meters ² / g or less is more preferable.
The specific surface area can be determined by the BET method by low-temperature, low-humidity physical adsorption of an inert gas. Specifically, a molecule having a known adsorption area such as nitrogen is adsorbed on the surface of the powder particles at the temperature of liquid nitrogen, and the specific surface area of the powder particles can be obtained from the adsorption amount.
As the inorganic filler having a specific surface area of 20 m ² / g or more, a commercially available product may be used. Commercially available products include, for example, fumed silica "AEROSIL (registered trademark) R972" (manufactured by Nippon Aerosil Co., Ltd., trade name, specific surface area 110 ± 20 m ² / g), "AEROSIL (registered trademark) R202" (Japan). Aerosil Co., Ltd., trade name, specific surface area 100 ± 20 m ² / g), colloidal silica "PL-1" (Fuso Chemical Industry Co., Ltd., trade name, specific surface area 181 m ² / g), "PL-7" (Manufactured by Fuso Chemical Industry Co., Ltd., trade name, specific surface area 36 m ² / g) and the like. Further, from the viewpoint of improving the moisture resistance, it is preferable that the inorganic filler is surface-treated with a surface treatment agent such as a silane coupling agent.

The content of the inorganic filler in the resin composition for the B layer is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and 3 to 20% by mass with respect to the solid content of the resin composition. More preferably, 5 to 20% by mass is particularly preferable. When the content of the inorganic filler is 1% by mass or more, better laser workability tends to be obtained, and when it is 30% by mass or less, the adhesiveness between the B layer and the conductor layer is further improved. There is a tendency.

The organic filler is not particularly limited, and is, for example, a crosslinked NBR particle obtained by copolymerizing acrylonitrile and butadiene, a copolymer of acrylonitrile butadiene such as a copolymer of acrylonitrile and butadiene and a carboxylic acid such as acrylic acid; and polybutadiene; , NBR, silicone rubber and the like as a core, and an acrylic acid derivative as a shell, so-called core-shell rubber particles and the like can be mentioned. By containing the organic filler, the extensibility of the resin layer tends to be further improved.

<Other ingredients>
In addition to the above-mentioned components, the resin composition for the B layer includes other thermosetting resins, thermoplastic resins, flame retardants, antioxidants, and flows as necessary, as long as the effects of the present invention are not impaired. Additives such as a modifier and a curing accelerator can be contained.

In the composite film of the present invention, the dielectric loss tangent of the cured product at 5 GHz is preferably 0.005 or less, and more preferably 0.0040 or less. The lower limit is not particularly limited, but may be 0.002 or more, or 0.0030 or more. The dielectric loss tangent can be obtained by the method described in the examples.

[Printed wiring board and its manufacturing method]
The printed wiring board of the present invention contains a cured product of the composite film of the present invention. In other words, the printed wiring board of the present invention has an interlayer insulating layer, and at least one of the interlayer insulating layers contains the resin composition.
Hereinafter, a method for manufacturing a multilayer printed wiring board by laminating the composite film of the present invention on a circuit board will be described.

The method for manufacturing a multilayer printed wiring board of the present invention has the following step (1). More specifically, the method for manufacturing a multilayer printed wiring board of the present invention includes the following steps (1) to (5), and after the step (1), the step (2) or the step (3), The support may be peeled off or removed.
Step (1): Laminating the composite film of the present invention on one or both sides of the circuit board Step (2): Curing the composite film to form an interlayer insulating layer Step (3): Forming an interlayer insulating layer Step (4): Roughening the surface of the interlayer insulating layer Step (5): Plate the surface of the roughened interlayer insulating layer

<Process (1)>
The step (1) is a step of laminating the composite film of the present invention on one side or both sides of the circuit board. Examples of the device for laminating the composite film include a vacuum laminator. A commercially available product can be used as the vacuum laminator. Examples of the commercially available vacuum laminator include a vacuum applicator manufactured by Nichigo Morton Co., Ltd., a vacuum pressurized laminator manufactured by Meiki Seisakusho Co., Ltd., and a vacuum pressurizing laminator manufactured by Hitachi Industries, Ltd. Roll type dry coater, vacuum laminator manufactured by Hitachi AIC Co., Ltd., etc. can be mentioned.

In the lamination, when the composite film has a protective film, after removing the protective film, the composite film is pressure-bonded to the circuit board while being pressurized and / or heated.
When a composite film is used, the layer A is arranged so as to face the surface of the circuit board on which the circuit is formed.
As for the laminating conditions, the composite film and the circuit board are preheated as necessary, the crimping temperature (lamination temperature) is 60 to 140 ° C., and the crimping pressure is 0.1 to 1.1 MPa (9.8 × 10 ^{4 to} 107). It may be laminated under a reduced pressure of .9 × 10 ⁴ N / m ² ) and an air pressure of 20 mmHg (26.7 hPa) or less. Further, the laminating method may be a batch method or a continuous method using a roll.
The substrate usually has a step due to a circuit or a component, but after laminating the composite film of the present invention on the substrate, the step can be sufficiently filled by the A layer of the composite film. From the viewpoint of ensuring a sufficient degree of filling, the lamination temperature is particularly preferably 70 to 130 ° C.

<Process (2)>
The step (2) is a step of curing the composite film to form an interlayer insulating layer. The curing may be thermosetting or curing by active energy rays. The conditions for thermosetting are not particularly limited, but can be selected, for example, at 170 to 220 ° C. for 20 to 80 minutes. The active energy rays are as described above.
After curing, the support may be peeled off.

<Process (3)>
The step (3) is a step of drilling a hole in the circuit board on which the interlayer insulating layer is formed. In this step, holes are drilled in the interlayer insulating layer and the circuit board by a method such as drilling, laser, plasma, or a combination thereof to form via holes, through holes, and the like. As the laser, a carbon dioxide gas laser, a YAG laser, a UV laser, an excimer laser and the like are generally used.

<Process (4)>
The step (4) is a step of roughening the surface of the interlayer insulating layer. In this step, the surface of the interlayer insulating layer formed in step (2) is roughened with an oxidizing agent, and at the same time, if via holes, through holes, etc. are formed, they are generated when they are formed. It is also possible to remove "smear".
The oxidizing agent is not particularly limited, and examples thereof include permanganate (potassium permanganate, sodium permanganate), dichromate, ozone, hydrogen peroxide, sulfuric acid, nitric acid and the like. Among these, alkaline permanganate solution (for example, potassium permanganate, sodium permanganate solution), which is an oxidizing agent commonly used for roughening the interlayer insulating layer in the production of a multilayer printed wiring board by the build-up method, is used. It may be used to roughen and remove smear.

<Process (5)>
The step (5) is a step of plating the surface of the roughened interlayer insulating layer. The B layer of the composite film is a layer that can be applied to the semi-additive method. Therefore, in this step, a feeding layer is formed on the surface of the interlayer insulating layer by electroless plating, then a plating resist having a pattern opposite to that of the conductor layer is formed, and a conductor layer (circuit) is formed by electrolytic plating. The additive method can be used.
After forming the conductor layer, for example, by performing an annealing treatment at 150 to 200 ° C. for 20 to 120 minutes, the adhesive strength between the interlayer insulating layer and the conductor layer can be improved and stabilized.

Further, it may have a step of roughening the surface of the conductor layer thus produced. Roughening the surface of the conductor layer has the effect of enhancing the adhesiveness with the resin in contact with the conductor layer. The treatment agent for roughening the conductor layer is not particularly limited, but for example, MEC Etch Bond CZ-8100, MEC Etch Bond CZ-8101, and MEC Etch Bond CZ-5480 (above, MEC Co., Ltd., trade name) and the like.

Among the above manufacturing methods, the following method for manufacturing a printed wiring board is mentioned as an example of a preferred embodiment from the features of the present invention.
A step of using the composite film to attach the A layer side of the composite film to a substrate having a step due to a circuit or a component on the surface and filling the step.
A step of curing the A layer and the B layer of the composite film,
A step of forming a circuit on the surface of the composite film on the B layer side by a semi-additive method,
A method for manufacturing a printed wiring board.

The composite film and printed wiring board of the present invention can be particularly suitably used for electronic devices that handle high-frequency signals of 1 GHz or higher, and in particular, electrons that handle high-frequency signals of 5 GHz or higher, high-frequency signals of 10 GHz or higher, or high-frequency signals of 30 GHz or higher. It can be suitably used for equipment. That is, the composite film of the present invention is useful as a composite film for electronic devices that uses signals in a high frequency band.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is of the present invention. Included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

Production Example 1 (Production of Polyimide Compound (a1))
1,6-Bismaleimide- (2,2,4-trimethyl) hexane (manufactured by Daiwa Kasei Kogyo Co., Ltd.) in a glass flask container with a mass of 1 L that can be heated and cooled equipped with a thermometer, a reflux condenser, and a stirrer. , Product name: BMI-TMH) 100 parts by mass, 2,2-bis [4- (4-maleimide phenoxy) phenyl] propane (manufactured by Daiwa Kasei Kogyo Co., Ltd., product name: BMI-4000) 418 parts by mass, 4, 4'-[1,3-Phenylenebis (1-methylethylidene)] Bisaniline (manufactured by Mitsui Kagaku Fine Co., Ltd., trade name: Bisaniline M) 72 parts by mass and 909 parts by mass of propylene glycol monomethyl ether are added and refluxed. , The reaction was carried out at a liquid temperature of 120 ° C. for 3 hours with stirring.
Then, it was confirmed that the weight average molecular weight of the reaction product was 3,000 by the measurement method described later, and the polyimide compound (a1) (solid content concentration: 65% by mass) was produced by cooling and filtering by 200 mesh.

<Measurement method of weight average molecular weight>
The weight average molecular weight of the obtained polyimide compound (a1) was converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve is standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, Product name]) was used for approximation by a cubic equation. The conditions for GPC are shown below.
Equipment: Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation]
Detector: L-3300 type RI [manufactured by Hitachi High-Technologies Corporation]
Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation]
Column: Guard column; TSK Guardcolum HHR-L + Column; TSK gel-G4000HHR + TSK gel-G2000HHR (all manufactured by Tosoh Corporation, product name)
Column size: 6.0 x 40 mm (guard column), 7.8 x 300 mm (column)
Eluent: tetrahydrofuran Sample concentration: 30 mg / 5 mL
Injection volume: 20 μL
Flow rate: 1.00 mL / min Measurement temperature: 40 ° C

<Manufacturing method of varnish for layer A>
Production Example 2 (Production of varnish A1)
As the inorganic filler (a2), silica (manufactured by Admatex Co., Ltd., trade name: SC-2050-KNK, methyl isobutyl ketone dispersion having a solid content concentration of 70% by mass) treated with an aminosilane coupling agent 65% by volume ( 20% by mass (total resin component, that is, inorganic filler and organic solvent) and polybutadiene-based elastoma (manufactured by Ebonic, trade name: POLYVEST 75MA) as the elastoma (a3) with respect to the total volume containing no organic solvent. For all the components not contained, the mixture was mixed in a blending ratio of.).
The polyimide compound (a1) obtained in Production Example 1 is mixed therewith at a ratio in which the content of the polyimide compound (a1) is 80% by mass with respect to the total resin components contained in the resin composition, and a high-speed rotation mixer is used. Was dissolved at room temperature.
After visually confirming that the polyimide compound (a1) was dissolved, 1,3-phenylenebis (di2,6-xyleneyl phosphate) (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: PX-) was used as a flame retardant. 200) in 1.0% by mass, as an antioxidant 4,4'-butylidenebis- (6-t-butyl-3-methylphenol) (manufactured by Mitsubishi Chemical Industry Co., Ltd., trade name: Yoshinox (registered trademark) BB) ( Hereinafter, "Yoshinox BB" is also referred to as 0.1% by mass, and "BYK310" (manufactured by BIC Chemie Japan Co., Ltd., trade name, xylene solution having a solid content concentration of 25% by mass) 0.1% by mass (hereinafter, also referred to as "Yoshinox BB") (Solid content) was mixed (however, each content is a value with respect to the solid content contained in the resin composition). After that, as a curing accelerator, an organic peroxide (manufactured by Nichiyu Co., Ltd., trade name: Perbutyl P) is used as a raw material (maleimide compound) converted from the amount of the polyimide compound (a1) charged and a polybutadiene-based elastoma (a3). 1.0 phr, isocyanate mask imidazole (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: G8009L) was mixed with 0.5 phr with the maleimide compound as a raw material converted from the amount of the polyimide compound (a1) charged. .. Then, it was dispersed by nanomizer treatment to obtain varnish A1.

Production Example 3 (Production of varnish A2)
In Production Example 2, the same operation was carried out except that the amount of the inorganic filler (a2) used was changed to 60% by volume to obtain varnish A2.

Production Example 4 (Production of varnish A3)
In Production Example 2, the same operation was carried out except that the amount of the inorganic filler (a2) used was changed to 57% by volume to obtain a varnish A3.

Production Example 5 (Production of varnish A4: for comparison)
In Production Example 2, the same operation was carried out except that the amount of the inorganic filler (a2) used was changed to 70% by volume to obtain a varnish A4.

<Manufacturing method of varnish for layer B>
Production Example 6 (Production of varnish B1)
A phenolic hydroxyl group-containing polybutadiene-modified polyamide resin (manufactured by Nippon Kayaku Co., Ltd., trade name: BPAM-155) having a solid content concentration of 6.4% by mass with respect to 100% by mass of the solid content contained in the resin composition. It was dissolved in a mixed solvent of dimethylacetamide and cyclohexanone [dimethylacetamide / cyclohexanone (mass ratio) = 7/3] so as to be 1.6% by mass. After dissolution, Aralquilnovolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: NC-3000H, epoxy equivalent 289 g / mol) was added to 57.2% by mass based on 100% by mass of the solid content contained in the resin composition. Inorganic filler (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil (registered trademark) R972, specific surface area 110 ± 20 m ² / g) is 8.8% by mass based on the solid content contained in the resin composition, and is an antioxidant. (Manufactured by API Corporation, trade name: Yoshinox (registered trademark) BB) is 0.4% by mass based on the solid content contained in the resin composition, phenoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., trade name: YX7200, Methyl ethyl ketone diluted product (35% by mass)) is 9.1% by mass in terms of solid content with respect to the solid content contained in the resin composition, and the active ester curing agent (manufactured by DIC Co., Ltd., trade name: HPC-8000-65T) (Toluene diluted product (65% by mass)) is 14.6% by mass in terms of solid content with respect to the solid content contained in the resin composition, and a flow conditioner (manufactured by Big Chemie Japan, trade name: BYK-310) (Same as that used in the production of varnish A1)) was 0.1% by mass in terms of solid content with respect to the solid content contained in the resin composition, and a phosphorus-based curing accelerator (tri-n-butylphosphine and p-) was added. (Addition with benzoquinone) was blended in an amount of 3.4% by mass based on the solid content contained in the resin composition and dissolved, and the varnish was diluted with methyl ethyl ketone so that the solid content concentration became 18% by mass. Dispersion by treatment gave varnish B1.

Production Example 7 (Production of varnish B2)
In Production Example 6, instead of the aralkyl novolac type epoxy resin, a phenoxy resin [manufactured by Mitsubishi Chemical Corporation, trade name: YX7200, diluted methyl ethyl ketone (solid content concentration: 35% by mass)] is used as a solid contained in the resin composition. The same operation was carried out except that the solid content was reduced to 15% by mass with respect to the amount of the varnish B2.

(1. Method for measuring melt viscosity)
Using the varnishes A1 to A4 for the A layer obtained in the above production example, the support was released from the mold (PET film, manufactured by Toray Film Processing Co., Ltd., trade name: Therapy SY (RX), thickness 38 μm). The films A1 to A4 were formed on the support by coating with a comma coater so that the thickness after drying was 25 μm and drying at 90 ° C. for 2 minutes.
Similarly, a support (PET film, manufactured by Toray Film Processing Co., Ltd., trade name: Therapy SY (RX)) which has been mold-released using the varnishes B1 to B2 for the B layer obtained in the above production example. The film (thickness 38 μm) was coated with a comma coater so that the thickness after drying was 2.5 μm, and dried at 140 ° C. for 3 minutes to form films B1 to B2 on the support.
The melt viscosities of these films A1 to A4 and B1 to B2 were measured according to the following method. Table 1 shows the minimum melt viscosities at 80 to 150 ° C.

An arbitrary number of sheets of each of the above films A1 were bonded together at a temperature at which curing did not proceed to form a single sheet having a thickness of 100 μm, and the sheet cut into 10 mm × 10 mm was used as a test piece A1. For films A2 to A4 and films B1 to B2, test pieces A2 to A4 and B1 to B2 were prepared in the same manner. In the preparation of the test piece, each film was bonded to the extent that peeling did not occur on the bonded surface during the following shear viscosity measurement.
For the melt viscosity, a rotary rheometer (ARES manufactured by TA Instruments) was used, and the film was sandwiched between parallel disks (diameter 8 mm) with a gap width 2 to 5 μm smaller than the film thickness, and the frequency was 1 Hz and the strain was 1%. Then, the value of the complex viscosity when measured from 30 ° C. to 300 ° C. at a heating rate of 5 ° C./min was used, and the minimum melt viscosity at 80 to 150 ° C. was focused on.

<Manufacturing of composite film>
Example 1
The varnish B1 for the B layer is applied to a release-treated support (PET film, manufactured by Toray Film Processing Co., Ltd., trade name: Therapy SY (RX), thickness 38 μm), and the thickness of the B layer after drying. The film was coated with a comma coater so as to have a thickness of 2.5 μm, and dried at 140 ° C. for 3 minutes to form a B layer on the support.
Next, the varnish A1 for the A layer is applied onto the resin layer of the B layer using a comma coater so that the thickness of the A layer after drying is 27.5 μm, and the temperature is 90 ° C. Drying for minutes gave a composite film.
Further, a polypropylene film having a thickness of 15 μm was bonded to the surface of the A layer and wound into a roll to obtain a composite film 1 having a support and a protective film.

Examples 2-5, Comparative Examples 1-3
In Example 1, the varnishes shown in Table 2 were used, and the same operations were carried out except that the films having the thicknesses shown in Table 2 were obtained to obtain composite films 2 to 8. Using the composite film, dielectric loss tangent, surface flatness, surface roughness, adhesiveness to plated copper, and embedding property were evaluated according to the following methods. The results are shown in Table 2.

<Manufacturing of resin plate>
The resin plate used for the measurement of the dielectric loss tangent was prepared by the following procedure.
(I) The protective film was peeled off from the composite film having the support and the protective film obtained in each example, and then dried at 120 ° C. for 3 minutes.
Next, a composite film having a support after drying is subjected to a copper foil (electric field copper foil, thickness) using a vacuum pressurizing laminator (manufactured by Meiki Seisakusho Co., Ltd., trade name: MVLP-500 / 600-II). The resin layer of the composite film and the copper foil were laminated on the glossy surface of 35 μm) so as to be in contact with each other to obtain a laminated body (P) in which the copper foil, the composite film, and the support were laminated in this order. The laminating was carried out by a method in which the pressure was reduced to 0.5 MPa for 30 seconds and then pressed at 120 ° C. for 30 seconds at a crimping pressure of 0.5 MPa. Then, the support was peeled off from the laminated body (P).
(II) Next, another composite film having a PET film as a support and a polypropylene film as a protective film was prepared, the protective film was peeled off, and then the film was dried at 110 ° C. for 3 minutes.
(III) Next, the resin layers of the laminated body (P) obtained by peeling off the support obtained in the above (I) and the composite film having the dried support obtained in the above (II) are formed by the resin layers. By laminating under the same conditions as in (I) above so as to abut, a laminated body (Q) in which a copper foil, a layer composed of two layers of composite films, and a support were laminated in this order was obtained. Then, the support was peeled off from the laminated body (Q).
(IV) Next, the laminated body (Q) obtained by peeling off the support obtained in (III) above and the composite film having the support after drying obtained by the same method as in (II) above are obtained. The resin layers were laminated under the same conditions as in (I) so that the resin layers were in contact with each other to obtain a laminated body (R) in which a copper foil, a layer composed of three composite film layers, and a support were laminated in this order.
(V) A laminated body (Q) was prepared by the same method as in (I) to (III) above.
(VI) The support of the laminated body (Q) obtained in the above (V) and the support of the laminated body (R) obtained in the above (I) to (IV) are peeled off from each other and laminated with the laminated body (Q). The resin layers of the body (R) were bonded to each other, and press molding was performed at 190 ° C. for 60 minutes at a crimping pressure of 3.0 MPa using a vacuum press. The obtained resin plate with a double-sided copper foil was cured at 190 ° C. for 2 hours, and then the copper foil was etched with ammonium persulfate to obtain a resin plate, which was used for measuring the dielectric loss tangent.

[2. Dissipation factor measurement method]
The resin plate produced above is cut into test pieces with a width of 2 mm and a length of 70 mm, and a network analyzer (manufactured by Agilent Technologies, Inc., trade name: E8364B) and a 5 GHz compatible cavity resonator (manufactured by Kanto Electronics Applied Development Co., Ltd.) Was used to measure the dielectric loss tangent. The measurement temperature was 25 ° C. The lower the dielectric loss tangent, the better the dielectric properties.

<Method of manufacturing substrate for surface roughness measurement>
A substrate for measuring surface roughness was prepared by the following procedure.
The composite film having the support and the protective film obtained in each example was cut into a size of 240 mm × 240 mm, and then the protective film was peeled off.
The composite film having the obtained support is laminated on a CZ-treated printed wiring board (manufactured by Hitachi Kasei Co., Ltd., trade name: E-700GR) so that the A layer and the printed wiring board are in contact with each other. did. Lamination was carried out by a method of pressing at 120 ° C. for 30 seconds at a crimping pressure of 0.5 MPa.
Then, it cooled to room temperature, and the printed wiring board which arranged the composite film was obtained. Next, the printed wiring board on which the composite film is arranged is cured in an explosion-proof dryer at 130 ° C. for 20 minutes as the first-stage curing with the support attached, and then as the second-stage curing. Curing was performed in an explosion-proof dryer at 190 ° C. for 40 minutes. Then, the support was peeled off to obtain a printed wiring board on which an interlayer insulating layer was formed.

(Roughening treatment method)
The printed wiring board obtained by the above method for manufacturing a substrate for surface roughness measurement is mixed with a swelling liquid (manufactured by Atotech Japan Co., Ltd., trade name: Swelling Dep Securigant (registered trademark) P) heated to 60 ° C. Immersion treatment for minutes. Next, it was immersed in a roughened solution heated to 80 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Consate Rate Compact CP) for 15 minutes. Subsequently, it was neutralized by being immersed in a neutralizing solution heated to 40 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Reduction Solution Security Gant (registered trademark) P500) for 5 minutes. The surface of the interlayer insulating layer roughened in this way was used as a substrate for surface roughness measurement.

[3. Surface Roughness Measurement Method: Surface Flatness]
Using a specific contact type surface roughness meter (manufactured by Bruker AXS Co., Ltd., trade name: wykoNT9100), the surface roughness of the surface roughness measurement substrate obtained above was measured with an internal lens of 1x and an external lens of 50x. The arithmetic average roughness (Ra) was obtained and used as an index of surface flatness.
From the viewpoint of surface flatness, it is preferable that the arithmetic mean roughness (Ra) is small, and particularly when it is less than 200 nm, it is suitable for forming fine wiring. Further, when it is 95 nm or more, sufficient peel strength can be exhibited. From this viewpoint, the surface flatness was evaluated as b when the surface roughness was less than 95 nm, a when the surface roughness was 95 nm or more and less than 200 nm, and c when the surface roughness was 200 nm or more.

[4. Evaluation method of adhesiveness with plated copper]
(1) Method for manufacturing a substrate for measuring adhesive strength (plating peel strength) with plated copper First, a printed wiring board with a composite film manufactured by the same method as the substrate for measuring surface roughness was cut out to a size of 40 mm × 60 mm and tested. It was a piece.
The test piece is roughened under the same conditions as the surface roughness measuring substrate, and then treated with an alkaline cleaner at 60 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Cleaner Security Gant (registered trademark) 902) for 5 minutes. And degreased and washed. After washing, it was treated with a predip solution at 23 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Predip Neogant (registered trademark) B) for 2 minutes. Then, it was treated with an activator solution at 40 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Activator Neogant (registered trademark) 834) for 5 minutes to attach a palladium catalyst. Next, it was treated with a reducing solution at 30 ° C. (manufactured by Atotech Japan Co., Ltd., trade name: Reducer Neogant (registered trademark) WA) for 5 minutes.
The test piece subjected to the above treatment is placed in a chemical copper solution (manufactured by Atotech Japan Co., Ltd., trade name: Basic Print Gantt (registered trademark) MSK-DK) until the plating thickness on the interlayer insulating layer reaches 1 μm. , Electroless plating was performed. After electroless plating, bake treatment was performed at 120 ° C. for 15 minutes in order to relieve the stress remaining in the plating film and remove the remaining hydrogen gas.
Next, the test piece subjected to the electroless plating treatment was further electroplated until the plating thickness on the interlayer insulating layer became 35 μm to form a copper layer as a conductor layer. After electrolytic plating, annealing treatment was performed at 190 ° C. for 120 minutes to obtain a measurement substrate before manufacturing the adhesive strength measuring section.
By forming a resist having a width of 10 mm on the copper layer of the obtained measurement substrate and etching the copper layer with ammonium persulfate, a substrate for measuring the adhesive strength with plated copper having a copper layer having a width of 10 mm as an adhesive strength measuring part. Got

(2) Measurement conditions of adhesive strength with plated copper One end of the copper layer of the adhesive strength measuring part formed on the substrate for measuring adhesive strength is peeled off at the interface between the copper layer and the interlayer insulating layer and grasped with a gripper, and a small desktop is used. Using a testing machine (manufactured by Shimadzu Corporation, trade name: EZT Test), the tensile speed was 50 mm / min in the vertical direction, and the load when peeled off at room temperature was measured, and the obtained adhesive strength (kN / m) was measured. ) Was used as an index of adhesiveness with plated copper. The larger the value, the higher the adhesiveness with the plated copper.

[Evaluation method of embedding]
The composite film obtained in each example was cut into a size of 240 mm × 240 mm, and then the protective film was peeled off.
A printed wiring board (manufactured by Hitachi Kasei Co., Ltd., trade name: E-700GR) in which the obtained composite film (with a support) is 18 μm thick and both 5 mm wide copper wiring and 100 μm wide copper wiring are formed. On top of this, the first resin layer and the printed wiring board were laminated so as to be in contact with each other. Lamination was carried out by a method of vacuuming at 100 ° C. for 15 seconds as the first stage, then pressurizing at 0.5 MPa for 45 seconds, and further pressing at 120 ° C. for 60 seconds at a crimping pressure of 0.5 MPa as the second stage. Then, it cooled to room temperature, and the printed wiring board which arranged the composite film was obtained.
Next, the printed wiring board on which the composite film is arranged is cured in an explosion-proof dryer at 130 ° C. for 20 minutes as the first-stage curing with the support attached, and then as the second-stage curing. Curing was carried out in an explosion-proof dryer at 190 ° C. for 40 minutes to obtain a printed wiring board on which an interlayer insulating layer was formed. Then, the support was peeled off to obtain a printed wiring board.
By visually observing the copper wiring part of this printed wiring board, the one having good embedding property and flatness of the copper wiring having a width of 5 mm and the copper wiring having a width of 100 μm is “A”, and the embedding property and flatness are both poor. The thing was evaluated as "C".

From Table 2, the printed wiring boards of Examples 2 and 3 have a small dielectric loss tangent, are excellent in embedding in irregularities of circuits and the like, and have a small surface roughness (that is, excellent surface flatness), but are made of plated copper. It can be seen that it has an interlayer insulating layer having excellent adhesiveness and is suitable for forming fine wiring.

The composite film of the present invention has a low dielectric loss tangent, excellent embedding property in irregularities such as circuits, excellent surface smoothness, and high adhesiveness to plated copper. Therefore, the composite film and printed wiring board of the present invention are useful for electric appliances such as computers, mobile phones, digital cameras and televisions, and vehicles such as motorcycles, automobiles, trains, ships and aircraft.

1 A layer 2 B layer 3 Support 4 Protective film

Claims (9)

Uses high frequency band signals with layer A having a minimum melt viscosity of 100-4,000 Pa · s at 80-150 ° C and layer B having a minimum melt viscosity of 50,000 Pa · s or more at 80-150 ° C. a composite film for electronic devices to be,
The layer A contains a polyimide compound having a structural unit derived from an aliphatic maleimide compound and a structural unit derived from a diamine compound, and an inorganic filler, and the number of carbon atoms between the imide groups of the aliphatic maleimide compound is high. A composite film for electronic devices that uses 6 to 40 signals in the high frequency band . The composite film for an electronic device using a signal in the high frequency band according to claim 1, wherein the thickness of the B layer is 1 to 5 μm. The composite film for an electronic device using a signal in the high frequency band according to claim 1 or 2, wherein the total thickness of the A layer and the B layer is 15 to 50 μm. The composite film for electronic devices using the signal in the high frequency band according to any one of claims 1 to 3, wherein the content of the structural unit derived from the aliphatic maleimide compound is 5 to 50% by mass in the polyimide compound. .. The composite film for electronic devices using the signal in the high frequency band according to any one of claims 1 to 4, wherein the B layer contains a polyfunctional epoxy resin and a phenolic hydroxyl group-containing polybutadiene-modified polyamide resin. The composite film for an electronic device using a signal in the high frequency band according to any one of claims 1 to 5, wherein the cured product has a dielectric loss tangent of 0.005 or less at 5 GHz. A printed wiring board containing a cured product of the composite film for electronic devices according to any one of claims 1 to 6. A method for manufacturing a printed wiring board, comprising the step (1) of laminating the composite film for electronic devices according to any one of claims 1 to 6 on one side or both sides of a base material. Using the composite film for electronic devices according to any one of claims 1 to 6, the A layer side of the composite film for electronic devices is attached to a substrate having a step due to a circuit or a component on the surface, and the step is formed. Filling process,
A step of curing the A layer and the B layer of the composite film for electronic devices,
A step of forming a circuit on the surface of the composite film for electronic devices on the B layer side by a semi-additive method.
A method for manufacturing a printed wiring board.

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