JP5112827B2 - Method for producing fiber-reinforced uncured film and fiber-reinforced uncured film - Google Patents

Description

  The present invention relates to a method for producing an uncured film reinforced with a fibrous base material (hereinafter referred to as “fiber reinforced uncured film”), a fiber reinforced uncured film, and an adhesive sheet obtained using the fiber reinforced uncured film. The present invention also relates to a laminated board for printed wiring, and an electronic component obtained using the laminated board for printed wiring.

  In recent years, in the field of electronic devices, particularly portable electronic devices such as notebook computers and mobile phones, miniaturization and thinning have been increasingly advanced. In printed wiring boards used in such electronic devices, in order to cope with high-density mounting, further fine wiring, high accuracy, and miniaturization have been problems.

In order to reduce the size and increase the performance of electronic devices, it is desired that multilayer printed wiring boards have a narrower conductor width and are arranged without gaps.
In order to meet such demands, it is desirable to make the copper foil as thin as possible (for example, about 12 μm or less). However, if the copper foil is made thin, it will be greatly affected by the surface irregularities of the laminated board to which the copper foil is attached. It becomes. Therefore, it is required to further improve the surface smoothness of the laminate.

As a system for mounting electronic components on a printed wiring board, a system using a chip mounter is often used.
Electronic components are mounted on a printed wiring board with respect to the printed wiring board in which dimensional changes such as warping and twisting have occurred due to thermal history during manufacturing.
Conventionally, as a base material constituting a prepreg that is an uncured sheet reinforced with a fibrous base material, a woven fabric (hereinafter also referred to as “glass cloth”) configured using glass fibers of the MIL standard 1080 type or the like. Since it was used, the influence of the dimensional change could be reduced. However, when a thinner glass cloth is used for the purpose of obtaining a thinner prepreg, in the step of impregnating the glass cloth with the varnish, the joint of the glass cloth is distorted, or the glass cloth cannot be uniformly impregnated with the varnish and bubbles ( There is a problem that voids remain.

  In the printed wiring board manufacturing technology, in recent years, a build-up method for producing a multilayer printed wiring board by alternately stacking organic insulating layers on a conductor layer of an inner circuit board has attracted attention. A method of manufacturing a multilayer printed wiring board using a foil and a vacuum lamination press is widely used for portable electronic devices.

In this buildup method, a copper foil with resin (RCC) or a resin film is used. However, a film-like adhesive alone having no reinforcing fiber has problems in dimensional stability, mechanical strength, heat resistance, and the like, and through-hole connection reliability is also regarded as a problem. Moreover, although it is used abundantly for portable devices, problems such as poor continuity also occur with a slight impact.
Therefore, from the viewpoint of mechanical strength and low deformation due to heat, a fibrous base material made of glass cloth, inorganic fiber web, organic fiber web or the like is impregnated with a thermosetting resin composition such as epoxy resin, so-called A In addition, an uncured prepreg in a B stage has been favorably used.
As the fibrous base material constituting such a prepreg, MIL standard 1080 type glass cloth, aramid fiber nonwoven fabric and the like are particularly preferably used from the viewpoint of good dimensional stability.

In a method for producing a fiber-reinforced uncured film, a vertical coating apparatus is generally used (see, for example, Patent Documents 1 to 3).
FIG. 3 shows an example of a method for producing a fiber-reinforced uncured film using a conventional vertical coating apparatus. In this vertical coating apparatus, the base material 31 is impregnated with the varnish 32, and then pulled up in the vertical direction, and the excess varnish 32 is scraped off at the roll nip 33.

  As another method for producing a fiber-reinforced uncured film, in Patent Document 4, a varnish is applied on a polyethylene terephthalate film with a die coater, and the solvent is evaporated and dried at 80 to 120 ° C., and then dried and solidified. Describes a method in which a glass cloth is heat-laminated and press-fitted under conditions of 50 ° C. and a linear pressure of 2 kg / cm.

JP 2001-269931 A JP 2003-285327 A JP 2004-196920 A JP 2004-241394 A

  In recent years, a thinner glass cloth is required in order to cope with high-density mounting, and a very thin glass cloth using a thinner filament has been used. However, the glass cloth using such thin filaments has small gaps between the fibers, so that the penetration of the varnish at the time of impregnation is incomplete, air replacement between the filaments is insufficient, and air bubbles (voids) in the dried prepreg Remains, and even after the heating and pressure molding, there is a problem that bubbles in the portion cannot be removed. If bubbles remain in the substrate even after heat-pressure molding of the fiber reinforced uncured film, there will be problems with migration due to chemical penetration, thermal expansion / contraction characteristics, insulation characteristics, moisture resistance characteristics, dielectric characteristics, etc. It can be a cause. That is, the bubbles remaining in the prepreg may cause a fatal defect in the fine circuit component.

In a vertical coating apparatus, in order to remove an excessive amount of varnish, it is necessary to apply a strong shearing force with a squeeze roll or the like, and thus a large load is applied when passing through the roll or the like. In addition, since an excessive amount of varnish is attached and then pulled up in the vertical direction, there is a problem that the resin droops and does not easily become a uniform thickness, and the base material is destroyed by the weight of the varnish. For example, when a varnish having a resin concentration of 20% by mass is used, in order to apply an equivalent amount of varnish to the substrate, the substrate mass is 5 times after the squeeze roll, and about 7 to 10 times before the squeeze roll. The mass will be added and lifted vertically. Such a problem becomes more serious as the glass cloth becomes thinner, leading to distortion in the width direction and distortion or breakage of the weave structure of the vertical and horizontal eyes, making production extremely difficult.
As described above, the method using the vertical coating apparatus has many problems when applied to a thin base material, and the uneven structure of the base material distribution due to joint misalignment and adhesion spots, resulting in uneven thickness due to bubbles, bubbles, etc. This leads to a uniform substrate structure.
The printed wiring board laminate produced using such a fiber-reinforced uncured film is subjected to uniformity in physical properties such as warp twist, linear expansion coefficient, hole workability, and various electrical properties. .
As these measures, it is conceivable to drastically reduce the coating speed in order to reduce the load when passing through a roll or the like, but the essential defects cannot be improved.
Such a problem is that, when the base material is extremely thin with a thickness of 20 μm or less, the structural strength of the base material is weakened. There is a problem that air bubbles are embraced and adhesion spots occur.

  In the method described in Patent Document 4 (hereinafter referred to as “dry laminating method”, the method of the present invention is sometimes referred to as “wet laminating method”), the film is laminated with a dried and solidified film. Because it is a joint with a high viscosity that does not contain a solvent, the wetting and penetration of the crossing of the fibers is particularly insufficient, and the air layer of the fibrous base material remains and bubbles are likely to form even after molding. There is a problem that bubbles tend to remain afterwards.

Therefore, the present invention is less likely to remain air bubbles in the fiber-reinforced uncured film, can prevent the destruction of the substrate even when using a relatively weak substrate, and can thin the fiber-reinforced uncured film, It aims at providing the manufacturing method of a fiber reinforced uncured film.
Moreover, an object of this invention is to provide the fiber reinforced uncured film with few bubbles.
Moreover, an object of this invention is to provide the adhesive sheet with few bubbles.
Another object of the present invention is to provide a laminated board for printed wiring that is thin, excellent in smoothness, low in relative dielectric constant and dielectric loss tangent.
Another object of the present invention is to provide an electronic component that can be miniaturized and has a low relative dielectric constant and low dielectric loss tangent.

As a result of intensive studies to solve the above problems, the present inventor applied a thermosetting resin composition containing a thermosetting resin and a volatile solvent and having a viscosity of 1000 mPa · s or less onto a support carrier. In the first step of forming the liquid coating film and the liquid coating film formed in the first step, the thickness is 8 to 100 μm and the air permeability is 5 to 200 cm ³ / cm ² / sec. And a second step of embedding a fibrous base material having an apparent density of 0.5 to 1.5 g / cm ³ , and embedding the fibrous base material in the liquid coating film in the second step And a third step of solidifying and integrating by volatilizing the volatile solvent in the liquid coating film to obtain a fiber-reinforced uncured film. Air bubbles are unlikely to remain in the uncured film and are relatively weak. It was found that even when a material is used, the substrate can be prevented from being broken, and the fiber-reinforced uncured film can be thinned, and the present invention has been completed.

That is, the present invention provides the following (1) to ( 17 ).
(1) a first step of applying a thermosetting resin composition containing a thermosetting resin and a volatile solvent and having a viscosity of 1000 mPa · s or less onto a support carrier to form a liquid coating film; ,
In the liquid coating film formed in the first step, the thickness is 8 to 100 μm, the air permeability is 5 to 200 cm ³ / cm ² / sec, and the apparent density is 0.5 to 1.5 g / second. a second step of burying a fibrous base material of cm ³ ;
After embedding the fibrous base material in the liquid coating film in the second step, the volatile solvent in the liquid coating film is volatilized and solidified to obtain a fiber-reinforced uncured film. The manufacturing method of the fiber reinforced uncured film which has a 3rd process.

  (2) The method for producing a fiber-reinforced uncured film according to (1), wherein the fibrous base material is a woven fabric or a non-woven fabric configured using glass fibers or aramid fibers.

(3) The fiber reinforced uncured film according to the above (2), wherein the woven fabric composed of the glass fibers is composed of filaments having an average diameter of 3 to 9 μm, and the unit mass is 5 to 50 g / m ² . Production method.

  (4) The woven fabric configured using the glass fiber is a glass fiber in which filament binding is relaxed by at least one type of opening treatment selected from the group consisting of water jet treatment and widening flattening treatment. The manufacturing method of the fiber reinforced uncured film as described in said (2) or (3) which is a woven fabric comprised by this.

  (5) The woven fabric constituted by using the glass fiber according to any one of (2) to (4), wherein a warp yarn density is 40 to 100 yarns / inch and a weft yarn density is 25 to 100 yarns / inch. Manufacturing method of fiber reinforced uncured film.

(6) The nonwoven fabric configured using the aramid fiber includes a fiber and a heat resistant resin,
The fiber contains 50% by mass or more of paraphenylene terephthalamide fiber having a fiber thickness of 2 denier or less,
The content of the heat resistant resin in the nonwoven fabric is 5 to 30% by mass,
The method for producing a fiber-reinforced uncured film according to the above (2), wherein the unit mass of the nonwoven fabric is 20 to 80 g / m ² .

  (7) The method for producing a fiber-reinforced uncured film according to any one of (1) to (6), wherein the content of the resin component in the thermosetting resin composition is 5 to 45% by mass.

  (8) Said (1)-(100) whose content of the said resin component is 40-75 mass% in the total 100 mass% of the said fiber base material and the resin component contained in the said thermosetting resin composition. The manufacturing method of the fiber reinforced uncured film in any one of 7).

  (9) The fiber-reinforced uncured film according to any one of (1) to (8), wherein the thermosetting resin is a thermosetting oligophenylene ether resin and / or an epoxy resin having functional groups at both ends. Manufacturing method.

  (10) The thermosetting resin composition comprises 100 parts by mass of a thermosetting oligophenylene ether (A) having a styrene functional group at both ends having a number average molecular weight of 500 to 5,000, and a vinyl aromatic hydrocarbon monomer. The fiber-reinforced non-woven fabric according to (9) above, which is a thermosetting resin composition containing a block copolymer (B) containing 50 to 250 parts by mass of a repeating unit derived from a repeating unit derived from a conjugated diene monomer. A method for producing a cured film.

(11) The linear epoxy resin (C) having a weight average molecular weight of 1,500 to 70,000, wherein the thermosetting resin composition has one or more hydroxy groups and two or more epoxy groups;
An epoxy resin composition containing a modified phenol novolak (D) obtained by esterifying at least a part of a phenolic hydroxy group with a fatty acid,
The manufacturing method of the fiber reinforced uncured film as described in said (9) whose content of the said modified phenol novolak (D) is 30-200 mass parts with respect to 100 mass parts of said linear epoxy resins (C).

  (12) The method for producing a fiber-reinforced uncured film according to (11), wherein the epoxy resin composition further contains an isocyanate compound.

  (13) The method for producing a fiber-reinforced uncured film according to the above (11) or (12), wherein the epoxy resin composition further contains divinylbenzene.

  (14) The method for producing a fiber-reinforced uncured film according to any one of (1) to (13), wherein the content of the resin component in the thermosetting resin composition is 10 to 40% by mass.

  (15) The method for producing a fiber-reinforced uncured film according to any one of (1) to (14), wherein the thickness of the fiber-reinforced uncured film is 10 to 120 μm.

  (16) Further, between the second step and the third step, the liquid coating film in which the fibrous base material is embedded in the second step is pressurized to defoam and smooth the surface. The manufacturing method of the fiber reinforced uncured film in any one of said (1)-(15) which has a 4th process to convert.

  (17) Furthermore, a thermosetting resin composition containing a thermosetting resin and a volatile solvent on the surface of the fiber-reinforced uncured film obtained in the third step and having a viscosity of 1000 mPa · s or less. The manufacturing method of the fiber reinforced uncured film in any one of said (1)-(16) which has the 5th process of volatilizing the said volatile solvent after apply | coating.

The method for producing a fiber-reinforced uncured film according to the present invention prevents bubbles from remaining in the fiber-reinforced uncured film and can prevent the substrate from being broken even when a relatively weak substrate is used. Thinning can be achieved.
The fiber-reinforced uncured film and adhesive sheet of the present invention have few bubbles.
The laminate for printed wiring of the present invention is thin, excellent in smoothness, and has a low relative dielectric constant and dielectric loss tangent.
The electronic component of the present invention can be miniaturized and has a low dielectric constant and dielectric loss tangent.

Hereinafter, the present invention will be described in more detail.
The method for producing a fiber-reinforced uncured film of the present invention (hereinafter referred to as “the production method of the present invention”) contains a thermosetting resin and a volatile solvent, and has a viscosity of 1000 mPa · s or less. In the first step of coating the composition on a support carrier to form a liquid coating film, and in the liquid coating film formed in the first step, the thickness is 8 to 100 μm and the air permeability is A second step of embedding a fibrous base material having an apparent density of 0.5 to 1.5 g / cm ³ in an amount of 5 to 200 cm ³ / cm ² / sec, and the liquid coating film in the second step. After the fiber base material is embedded therein, the volatile solvent in the liquid coating film is volatilized and solidified and integrated to obtain a fiber reinforced uncured film. It is a manufacturing method of a cured film.
The conventional prepreg is, for example, a sheet having a thickness of about 250 μm after molding and a thickness exceeding 100 μm, whereas the present invention is preferably a thin film having a thickness of 100 μm or less. It is called an uncured film.

An example of the manufacturing method of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a preferred example of the production method of the present invention.
First, a support carrier 3 such as an organic film or a metal foil is sent to a coating apparatus 5 such as a gravure coater, and a varnish (thermosetting resin composition) is applied to the surface to form a liquid coating film 7. (First step).
Next, the fibrous base material 9 is embedded in the liquid coating film 7 (second step).
Next, if necessary, the pressure roll 11 pressurizes the liquid coating film 7 in which the fibrous base material 9 is embedded to defoam and smooth the surface (fourth step).
Next, the volatile solvent in the liquid coating film 7 is volatilized by the drying furnace 13 to solidify the liquid coating film and integrate it with the fibrous base material to obtain the fiber reinforced uncured film 1 (third) Process).

Next, FIG. 2 shows another preferred example of the production method of the present invention.
FIG. 2 is a schematic view showing another preferred example of the production method of the present invention.
The process up to solidification and integration by volatilizing the volatile solvent in the liquid coating film 7 by the drying furnace 13 is the same as the method shown in FIG. 1, but after that, the obtained fiber-reinforced uncured film On the surface, the thermosetting resin composition is applied by the coating device 15 and the volatile solvent is volatilized by the drying furnace 17 to obtain the fiber reinforced uncured film 1 (fifth step).
Hereafter, each process of the manufacturing method of this invention is demonstrated in detail.

<First step>
In the first step, a thermosetting resin composition containing a thermosetting resin and a volatile solvent and having a viscosity of 1000 mPa · s or less is applied onto a support carrier to form a liquid coating film.
The present invention uses a thermosetting resin composition having a viscosity lower than that of a thermosetting resin composition usually used in the dry laminating method described in Patent Document 4 and the like. And in the 2nd process mentioned below, a fibrous base material is embed | buried in the liquid coating film which consists of a thermosetting resin composition, without drying a thermosetting resin composition. Therefore, it becomes easy for the fibrous base material to be impregnated with resin, and even when a fibrous base material composed of thin filaments is used, a fiber-reinforced uncured film with few remaining bubbles can be obtained.

The support carrier used in the production method of the present invention is not particularly limited, and examples thereof include organic films such as polyester resin and polyethylene resin: metal foils such as copper foil, aluminum foil, and stainless steel foil. When copper foil is used for the support carrier, a single-sided copper foil-clad laminate for printed wiring can be obtained by a simple method by heating and curing the fiber-reinforced uncured film with the support carrier obtained by the production method of the present invention. It can be.
Further, the support may be subjected to a release treatment with a silicone compound or the like.

The said thermosetting resin composition will not be specifically limited if it contains a thermosetting resin and a volatile solvent, and the viscosity in 25 degreeC is 1000 mPa * s or less.
When the viscosity of the thermosetting resin composition is within this range, the impregnation property to the fibrous base material is good, and in the woven fabric structure, the penetration of the varnish into the yarn bundle and filament bundle is good. Has good wettability with the surface of each fiber, so that it is possible to obtain a fiber-reinforced uncured film that is less likely to generate bubbles and has no bubble defects.
In addition, it is easy to apply a desired amount of resin, and since a homogeneous resin can permeate, it is difficult to leave bubbles, and even when using a fibrous base material with a smaller gap between fibers, a fiber reinforced uncured film with less bubbles From the point which can be obtained, it is preferable that the viscosity at 25 degreeC of the said thermosetting resin composition is 20-1000 mPa * s, and it is more preferable that it is 50-500 mPa * s.

  In addition, in this specification, a viscosity is shown by the value measured at 25 degreeC using the E-type viscosity meter (TVE-22LT, the Toki Sangyo company make).

  Examples of the thermosetting resin used in the thermosetting resin composition include a thermosetting oligo having functional groups such as a styrene functional group, a vinyl group, a glycidyl group, an amino group, a hydroxy group, and a carboxy group at both ends. Examples include phenylene ether resins and epoxy resins. Among these, thermosetting oligophenylene ether resins and epoxy resins having styrene functional groups at both ends are excellent in dielectric properties (for example, low dielectric constant, low dielectric loss tangent), low water absorption, and film formability. To preferred.

  As the thermosetting resin composition, an oligophenylene ether-based resin composition described in Japanese Patent Application No. 2006-215464 previously filed by the applicant of the present application is particularly preferable. Specifically, for example, 100 parts by mass of thermosetting oligophenylene ether (A) having a styrene functional group at both ends with a number average molecular weight of 500 to 5000, a repeating unit derived from a vinyl aromatic hydrocarbon monomer, and a conjugated diene A thermosetting resin composition containing 50 to 250 parts by mass of a block copolymer (B) containing a repeating unit derived from a monomer has dielectric properties (eg, low dielectric constant, low dielectric loss tangent), low elasticity, Preferable examples are from the viewpoint of excellent coating film formability.

  Examples of the thermosetting oligophenylene ether (A) include 2,2 ′, 3,3 ′, 5,5′-hexamethylbiphenyl-4,4 ′ described in JP-A-2006-28111. -Reaction product of diol-2,6-dimethylphenol polycondensate and chloromethylstyrene.

  Such a thermosetting oligophenylene ether (A) can be produced by a known method. Commercial products can also be used. For example, OPE-2st 2200 (manufactured by Mitsubishi Gas Chemical Company) can be suitably used.

  When the number average molecular weight of the thermosetting oligophenylene ether (A) exceeds 5,000, it is difficult to dissolve in a volatile solvent. On the other hand, if the number average molecular weight is less than 500, the crosslink density becomes too high, which adversely affects the elastic modulus and flexibility of the cured product. Therefore, the number average molecular weight of the thermosetting oligophenylene ether (A) is 500 to 5,000, and preferably 1,000 to 3,000.

The block copolymer (B) is a block copolymer composed of a hard segment block part mainly composed of vinyl aromatic hydrocarbon and a soft segment block part mainly composed of conjugated diene.
Examples of the block copolymer (B) include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, and a styrene-ethylene-butadiene-styrene block copolymer.

  The block copolymer (B) can be produced by a known method. Commercial products can also be used. For example, TR2003 (manufactured by JSR) can be suitably used.

  Content of the block copolymer (B) in the said thermosetting resin composition is 50-250 mass parts with respect to 100 mass parts of thermosetting oligophenylene ether (A), and is 65-200 mass parts. It is preferable that it is, and it is more preferable that it is 80-150. When the content of the block copolymer (B) is within this range, the film forming ability and the compatibility with the thermosetting oligophenylene ether (A) are excellent.

  Examples of the volatile solvent used in the oligophenylene ether resin composition include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, and these are used alone. Or two or more of them may be used in combination.

  The content of the volatile solvent is not particularly limited as long as the viscosity of the composition is appropriately adjusted so as to be in the above range, but is preferably used so that the resin component is 5 to 45% by mass. It is more preferable to use it so that it may become 40 mass%, and it is still more preferable to use it so that it may become 10-35 mass%. The present invention can be applied without any hindrance to uniform coating even in the low concentration region even if the total weight including the solvent increases. Moreover, it becomes easy to impregnate a fibrous base material as the ratio of the resin component in a composition is this range, and it can reduce a bubble. At such a low concentration, in a conventional vertical impregnation apparatus, in order to obtain a desired resin adhesion amount, a large amount of varnish adhesion amount must be obtained, and the impregnated resin droops when proceeding in the vertical direction. In addition to non-uniform vertical stripes and terrible resin spots, there is a phenomenon that the solvent remains in the coating film and only the surface is dried, and a uniform uncured state is not obtained.

  The above-mentioned oligophenylene ether resin composition is a range that does not impair the effects of the present invention, such as an inorganic filler, a tackifier, a flame retardant, a defoaming agent, a flow regulator, a film forming aid, a dispersion aid, etc. An additive may be contained.

  The oligophenylene ether resin composition may contain a curing catalyst, but can be cured only by heating.

  The manufacturing method of the said oligophenylene ether resin composition is not specifically limited, A well-known manufacturing method is employable. For example, the components described above can be produced by sufficiently mixing with a stirrer.

  Moreover, as said thermosetting resin composition, the epoxy resin composition described in the international publication 2005/100435 pamphlet can also be used conveniently. Specifically, a linear epoxy resin (C) having a weight average molecular weight of 1,500 to 70,000 having one or more hydroxy groups and two or more epoxy groups, and at least a part of the phenolic hydroxy groups An epoxy resin composition containing a modified phenol novolak (D) esterified with a fatty acid, wherein the content of the modified phenol novolak (D) is 100 parts by mass of the linear epoxy resin (C). An epoxy resin composition that is 30 to 200 parts by mass is preferable because it has excellent dielectric properties (for example, low dielectric constant and low dielectric loss tangent).

The weight average molecular weight of the linear epoxy resin (C) is 1,500 to 70,000.
The number average molecular weight of the linear epoxy resin (C) is preferably 3,700 to 74,000, more preferably 5,500 to 26,000.
The epoxy equivalent of the linear epoxy resin (C) is preferably 5000 g / eq or more.
In this specification, the weight average molecular weight and the number average molecular weight are values using a standard polystyrene calibration curve by gel permeation chromatography (GPC).
As the linear epoxy resin (C), those having a weight average molecular weight / number average molecular weight in the range of 2 to 3 are particularly preferable.
As the linear epoxy resin (C), specifically, for example, a compound represented by the following formula (1) is preferable, and a compound represented by the following formula (2) is more preferable.

In the above formulas, X and Y are each a single bond, a hydrocarbon group having 1 to 7 carbon atoms, —O—, —S—, —SO ₂ —, —CO—, or a group represented by the following formula. When there are a plurality of X and Y, they may be the same or different.

Here, R ² in the above formula is a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, and when there are a plurality of R ^{2 s} , they may be the same or different. R ³ is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogen atom. q is an integer of 0-5.

In the above formula (1) ~ (2), R 1 and R ⁴ are each a hydrocarbon group or a halogen atom having 1 to 10 carbon atoms. When there are a plurality of R ¹ and R ^{4 s} , they may be the same or different.
p and s are each an integer of 0 to 4, and may be the same or different.
In said formula (1), n represents an average value and is 25-500.
In said formula (2), t represents an average value and is 10-250.

  The linear epoxy resin (C) is more preferably a compound represented by the formula (1 ′) in which p is 0 in the above formula (1).

In said formula, X and n are synonymous with X and n in said formula (1), respectively.
The linear epoxy resin (C) mentioned above may be used independently and may use 2 or more types together.

  Preferred examples of the modified phenol novolak (D) obtained by fatty acid esterification of at least a part of the phenolic hydroxy group include a modified phenol novolak represented by the following formula (3).

In the above formula (3), R ⁵ represents an alkyl group having 1 to 5 carbon atoms, preferably a methyl group, the plurality of R ^5, may be the same or different.
R ⁶ represents an alkyl group having 1 to 5 carbon atoms, a phenyl group which may have a substituent, an aralkyl group which may have a substituent, an alkoxy group or a halogen atom, and a plurality of R ⁶ are the same Or different.
R ⁷ represents an alkyl group having 1 to 5 carbon atoms, a phenyl group which may have a substituent, an aralkyl group which may have a substituent, an alkoxy group or a halogen atom, and a plurality of R ^{7 s} , May be the same or different.
g represents an integer of 0 to 3, and a plurality of g may be the same or different.
h represents an integer of 0 to 3, and a plurality of h may be the same or different.
n: m is 1: 1 to 1.2: 1, preferably about 1: 1.
The total of n and m can be 2 to 4, for example.

  In the above formula (3), n and m are average values of repeating units, and the order of repeating units is not limited, and may be block or random.

  The modified phenol novolak (D) is preferably a modified phenol novolak represented by the following formula (3 ′).

In the formula (3 '), R ^5, n and m are each the same as R ^5, n and m in the formula (3).
Particularly preferably, in the above formula (3 ′), R ⁵ is an acetylated phenol novolak having a methyl group.

  These modified phenol novolacs may be used alone or in combination of two or more.

  It is preferable that content of the said (D) component is 30-200 mass parts with respect to 100 mass parts of said (C) component. When the content of the component (D) is within this range, the dielectric properties, film formability, and curing reactivity are excellent. As for content of the said (D) component, it is more preferable that it is 50-180 mass parts with respect to 100 mass parts of said (C) component.

  About the kind and usage-amount of the volatile solvent used for the said epoxy resin composition, it is the same as that in the oligo phenylene ether resin composition mentioned above.

  In one preferred embodiment, the epoxy resin composition further contains an isocyanate compound. When there is a hydroxy group in the epoxy resin, the hydroxy group or the hydroxy group generated when the epoxy resin is ring-opened reacts with the isocyanate group in the isocyanate compound to form a urethane bond. The crosslink density of the polymer is increased, the molecular mobility is further lowered, and the number of highly polar hydroxy groups is reduced. Therefore, it is possible to further lower the relative dielectric constant and the dielectric loss tangent. Furthermore, the epoxy resin has a large intermolecular force, it is difficult to form a uniform film when it is made into a film, and even if it is made into a film, the film strength is weak and tends to crack during film formation. These disadvantages can be eliminated by blending.

Examples of the isocyanate compound include compounds having two or more isocyanate groups. For example, hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, trimethylhexamethylene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, cyclohexene Examples include xylene diisocyanate, dimer acid diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, and tri (isocyanatephenyl) triphosphate. These may be used alone or in combination of two or more.
Among these, hexamethylene diisocyanate and diphenylmethane diisocyanate are preferable.

  The isocyanate compound includes a prepolymer in which a part of the isocyanate compound forms an isocyanurate ring by a cyclization reaction. For example, the prepolymer containing the trimer of an isocyanate compound is mentioned.

  The isocyanate compound is particularly preferably used in combination with the above-described linear epoxy resin (C). In addition to the reaction between the generated hydroxy group and the isocyanate group accompanying the ring-opening reaction of the epoxy resin, since the hydroxy group exists in the linear epoxy resin (C), the hydroxy group and the isocyanate group can react. Therefore, a greater effect can be obtained.

  The content of the isocyanate compound is preferably 100 to 400 parts by mass and more preferably 300 to 350 parts by mass with respect to 100 parts by mass of the component (C). When the content of the isocyanate compound is within this range, foaming is suppressed when cured and a uniform film is easily formed, and cracks are less likely to occur after curing, resulting in dielectric properties (eg, low dielectric constant, low dielectric loss tangent). Also excellent.

In one preferred embodiment, the epoxy resin composition further contains divinylbenzene. When divinylbenzene is contained, the melting temperature of the crosslinking component is lowered, the fluidity during molding is improved, the curing temperature is lowered, and the compatibility is improved.
The content of divinylbenzene is preferably 50 to 150 parts by mass with respect to 100 parts by mass of the component (C).

The epoxy resin composition may contain a curing accelerator as an optional component.
As a hardening accelerator, what is known as a hardening accelerator of an epoxy resin composition can be used, for example, heterocyclic compound imidazoles, such as 2-methylimidazole and 2-ethyl-4-methylimidazole, Phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, tertiary amines such as 2,4,6-tris (dimethylaminomethyl) phenol and benzyldimethylamine, 1,8-diazabicyclo (5,4 , 0) DBUs such as undecene and its salts, amines and imidazoles are adducted with epoxy, urea, acid, etc., and adduct type accelerators.
It is preferable that content of a hardening accelerator is 1-10 mass parts with respect to 100 mass parts of said (C) component.

The epoxy resin composition may contain a polymerization initiator as an optional component.
As the polymerization initiator, a known polymerization initiator can be used. For example, benzoyl peroxide, azobisisobutyronitrile, t-butylperoxybenzoate, 1,1,3,3-tetramethylbutylperoxy -2-ethylhexanoate and the like.
It is preferable that content of a polymerization initiator is 1-10 mass parts with respect to 100 mass parts of said (C) component.

  The said epoxy resin composition may contain additives, such as a tackifier, a flame retardant, an antifoamer, a flow regulator, a dispersion | distribution adjuvant, as needed.

In addition, the epoxy resin composition is used within the range not impairing the object of the present invention, for the purpose of improving the elastic modulus, lowering the expansion coefficient, changing the glass transition temperature (Tg value), etc. ) An epoxy resin other than the component may be contained.
Examples of the epoxy resin other than the component (C) include a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, an alicyclic epoxy resin, and a biphenyl epoxy resin. These may be used alone or in combination of two or more.

Moreover, the said epoxy resin composition may contain well-known epoxy resin hardening | curing agents, such as a phenol novolak, a cresol novolak resin, a phenol polynuclear body, etc. which are not fatty acid esterified, in the range which does not impair the objective of this invention.
As a phenol polynuclear body, phenols, such as a 3-5 nuclei grade, are mentioned, for example.

The said epoxy resin composition can be manufactured by a well-known method. For example, each of the components (C), (D) and optionally (E) can be mixed with a propeller stirrer, Banbury mixer, planetary mixer, heating vacuum mixing kneader or the like in the presence or absence of a solvent.
Further, for example, the resin components can be dissolved in a predetermined solvent concentration, and a predetermined amount thereof can be put into a reaction kettle heated to 25 to 60 ° C., and normal pressure mixing can be performed for 30 minutes to 6 hours. Thereafter, the mixture can be further stirred for 5 to 60 minutes under vacuum (maximum 1 Torr).

  The content of the resin component in the thermosetting resin composition described above is preferably 5 to 45% by mass, more preferably 10 to 40% by mass, and even more preferably 10 to 35% by mass. preferable. When the ratio of the resin component in the composition is within this range, the fibrous base material can be easily impregnated, and bubbles can be reduced.

  The method for applying the thermosetting resin composition described above onto the support carrier is not particularly limited, and can be applied using, for example, a curtain coater, a gravure coater, a die coater or the like.

  The coating amount of the thermosetting resin composition is not particularly limited as long as the liquid coating film can be formed so that the fibrous base material can be embedded in the second step described later. For example, the thickness of the coating film after drying Is preferably 5 to 120 μm, more preferably 10 to 100 μm.

Next, the second step will be described.
In the second step, the thickness of the liquid coating film formed in the first step is 8 to 100 μm, the air permeability is 5 to 200 cm ³ / cm ² / sec, and the apparent density is 0.00. This is a step of embedding a fibrous base material of 5 to 1.5 g / cm ³ .
The manufacturing method of this invention embeds a fibrous base material in the liquid coating film which consists of a thermosetting resin composition in this 2nd process, without drying a thermosetting resin composition. Therefore, it becomes easy for the fibrous base material to be impregnated with resin, and even when a fibrous base material composed of thin filaments is used, a fiber-reinforced uncured film with few remaining bubbles can be obtained.

The fibrous base material used in the production method of the present invention is composed of fibers made of an inorganic material or an organic material, has a thickness of 8 to 100 μm, and an air permeability of 5 to 200 cm ³ / cm ² / sec, and The apparent density is 0.5 to 1.5 g / cm ³ .

The thickness of the fibrous base material is 8 to 100 μm, preferably 8 to 80 μm, and more preferably 8 to 60 μm. When the thickness of the fibrous base material is within this range, it can be a fiber reinforced uncured film made of an extremely thin fiber base material, and the centrally arranged core substrate can be made thin even in a high-layer build-up printed wiring board. Or a coreless build-up printed wiring board, which greatly improves electrical characteristics.
In the conventional method for producing a fiber base reinforced prepreg, when such an ultrathin base material is used, there is a problem such as destruction of the base material structure. However, according to the manufacturing method of the present invention, such a problem is caused. Can be solved.
In addition, in this specification, the thickness of the fibrous base material was measured using a contact-type film thickness measuring device (Millitron No. 1240, manufactured by Marl Japan, contact terminal diameter φ10 mm, contact pressure 0.025 kg). Indicated by value.

Air permeability of the fibrous base material is a 5~200cm ³ / cm ² / sec, is preferably from 20~180cm ³ / cm ² / sec, and even a 40~160cm ³ / cm ² / sec More preferred. When the air permeability of the fibrous base material is within this range, the penetration rate of the thermosetting resin composition, so-called varnish is fast, and the wetness to the fiber filament surface is good. Can do.
In addition, in this specification, air permeability is shown by the value measured according to JISL1096-1999 (general textiles test method breathability A method Frazy).

The apparent density of the fibrous base material is 0.5 to 1.5 g / cm ^3, is preferably from 0.6~1.3g / cm ^3, in 0.8~1.2g / cm ³ More preferably. When the apparent density of the fibrous base material is within this range, the ratio of the thermosetting resin and the fibrous base material can increase the effect of thermal expansion performance expected by fiber reinforcement. That is, as a constituent ratio of the fiber-reinforced uncured film, the ratio of the thermosetting resin can be easily set to 40 to 70% by mass.
In the present specification, the apparent density is indicated by a numerical value (g / cm ³ ) obtained by dividing a unit mass (g / m ² ) by a thickness (μm).

  Examples of the fibrous base material include, for example, woven fabric (glass cloth) made of glass fiber, glass nonwoven fabric (heat-resistant binder strengthened); Examples include woven fabrics and nonwoven fabrics composed of heat-resistant fibers. Among these, glass cloth and polyphenylene terephthalamide (aramid) non-woven fabric are preferable from the viewpoint of performance effect of preventing thermal expansion.

As glass fibers used for the glass cloth, E glass (relative dielectric constant ε ′ = 7, dielectric loss tangent tan δ = 0.003, 1 GHz), D glass (ε = 4, tan δ = 0.003, 1 GHz), H Glass (ε = 11, tan δ = 0.003, 1 GHz), C glass, S glass, NE glass, and other glass component compositions can be mentioned, but from the viewpoint of balance between cost and dielectric properties. E glass is preferably used.
However, the relative dielectric constant after curing of the thermosetting resin of the present invention is, for example, 3 or less, whereas the relative dielectric constant of this E glass is as high as 7, and the relative dielectric constant of the above fiber substrate reinforcement Becomes 3 or more. As a countermeasure, for example, a glass cloth composed of E glass fiber as disclosed in Japanese Patent Application Laid-Open No. 2003-41486 is leached with an acidic solvent, for example, 10% nitric acid aqueous solution at a temperature of 80 ° C., and the mass is reduced by 30% Then, a glass cloth or the like whose dielectric properties have been improved by heat cleaning and silane coupling agent treatment can be suitably used.
The glass fiber used for the said glass cloth can be used conveniently from the point that it consists of a filament with an average diameter of 3-9 micrometers, and unit mass is 5-50 g / m < ² > as an ultra-thin fiber base material.

The average diameter of the glass fiber (that is, the filament) is 3 to 9 μm, preferably 3.5 to 7.5 μm, and more preferably 5 μm or less. Those having an average diameter of less than 3 μm are restricted in terms of industrial production and environment. When the average diameter of the glass fiber is within this range, the fiber-reinforced uncured film can be made thinner and thinner, and high-density mounting becomes possible.
In addition, in this specification, the average diameter of a glass cloth is shown by the value measured with the electron microscope.

Unit mass of the glass cloth is a 5 to 50 g / m ^2, is preferably from 7~38g / m ^2, and more preferably 8~25g / m ^2. When the unit mass of the glass cloth is within this range, the thickness becomes an appropriate value, and the ratio between the thermosetting resin and the fiber base material is suitable for controlling the thermal expansion.
In this specification, the unit mass is a unit of g / m ^{2 obtained} by weighing a 10 cm × 10 cm mass and multiplying it by 100.

  The glass cloth is a glass cloth in which filament binding is relaxed by at least one type of fiber opening treatment selected from the group consisting of water jet treatment and widening flattening treatment. It is preferable from the viewpoint that it becomes easy to impregnate and a fiber-reinforced uncured film with few bubbles is obtained. In particular, it is preferable to widen and flatten the warp yarns of glass cloth from the viewpoint of obtaining a fiber-reinforced uncured film with fewer bubbles.

The water jet treatment is a treatment that relaxes filament binding by bringing a high-pressure water spray into contact with a glass cloth, and, for example, a method described in Japanese Patent Application Laid-Open No. 2004-277888 is preferably exemplified. Specifically, for example, a physical processing and drying in a range where the tension applied to one warp constituting the glass cloth is 2 × 10 ⁻⁵ to 2 × 10 ⁻² N, machining process is a physical process using water having a pressure in the range of 10N / cm ² ~1000N / cm ² are preferably exemplified.

  The above-mentioned widening and flattening treatment is a treatment for widening and flattening the filaments to relax the filament binding, and for example, a method described in JP-A-2005-213656 is preferable. Specifically, the twist number of the glass yarn is preferably 0 to 0.7 times / inch, more preferably 0 to 0.5 times / inch, and 0 to 0.3 times / inch. More preferably. By making the yarn low, the yarn width can be easily expanded and the thickness of the glass cloth can be easily reduced. Further, by using a low twist yarn, the yarn is flattened, the cross-sectional shape of the yarn itself approaches the shape of a flat plate from an elliptical shape, and the distribution of the glass fibers in the glass cloth becomes more uniform.

  The glass cloth preferably has a warp weave density of 40 to 100 yarns / inch and a weft yarn density of 25 to 100 yarns / inch. The warp yarn density is 50 to 80 yarns / inch and the weft yarn density is 30 to 80 yarns / inch. Inch is more preferable. Within this range, the fiber base material can be easily impregnated with the resin, and a fiber-reinforced uncured film with few remaining bubbles can be obtained even when a fibrous base material composed of thin filaments is used.

The glass fiber used for the glass cloth is preferably treated with a silane coupling agent.
Examples of the silane coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-anilinopropyltri. Methoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-aminoethyl-γ-aminopropyltrimethoxysilane (hydrochloride), γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like. These may be used alone or in combination of two or more.
0.01-2 mass% is preferable and the adhesion amount to glass fiber has more preferable 0.05-0.5 mass%.

The manufacturing method of the said glass cloth is not specifically limited, It can manufacture by a well-known method. For example, the method described in JP-A-2004-050755 is preferably exemplified. Below, the specific example of the manufacturing method of a glass cloth is shown.
E glass composition glass yarn with an average diameter of monofilament of 4.5μm, 100 monofilaments and 1.0Z twist is used for the warp and weft yarns. In the air jet loom, the warp yarns are 70 yarns / inch and the weft yarns are 73 yarns / inch. Glass is woven at a weaving density, and the resulting green machine is subjected to relaxation treatment (working pressure 20 kgf / cm ² ) with a water jet. Then, high temperature de-glue is performed at 400 ° C. for 24 hours. Subsequently, SZ6032 (manufactured by Dow Corning Toray Co., Ltd.), which is a silane coupling agent, is used as a surface treatment, and the glass cloth is immersed in the solution. An ultrathin glass cloth having 028 mm, a mass of 23 g / m ² , an air permeability of 61 cm ³ / cm ² / sec, a longitudinal direction thread-thread interval of 0.212 mm, and a transverse direction thread-thread interval of 0.005 mm can be obtained. The water pressure in the water jet treatment is preferably 0.2 to 10 MPa or more, and more preferably 1 to 5 MPa.

As a nonwoven fabric comprised using the said aramid fiber, the nonwoven fabric described in Unexamined-Japanese-Patent No. 2002-302893 is mentioned suitably, for example. Moreover, the fiber contains 50 mass% or more of paraphenylene terephthalamide fibers having a fiber thickness of 2 denier or less, and the content of the heat resistant resin in the nonwoven fabric is 5 to 30. The aramid nonwoven fabric, which is mass% and the unit mass of the nonwoven fabric is 20 to 80 g / m ² , is preferably mentioned from the viewpoints of varnish impregnation property, thickness uniformity, and through-hole processability.

The fiber thickness (fineness) of the paraphenylene terephthalamide fiber is 2 denier or less, preferably 0.1 to 1.7 denier, and more preferably 0.1 to 1.5 denier. .
A fiber thickness of 1 denier or less is obtained by beating a polyparaphenylene ether fiber filament of a larger thickness physically, for example, with a refiner, etc. It is effective for improving the web strength and homogenizing the texture. Those having a fiber thickness (fineness) of more than 2 denier are composed of fine fibers of 1.5 denier or less because the density of the number of fibers is low and smoothness does not occur when compared with the mass per area. It is preferable.

Unit weight of the nonwoven fabric is 20 to 100 g / m ^2, is preferably from 23~80g / m ^2, and more preferably 25~60g / m ^2. When the unit mass of the nonwoven fabric is within this range, the fiber-reinforced uncured film of the present invention can be easily made extremely thin.
In addition, it is preferable that the fiber-reinforced uncured film of the present invention is densely finished by a high-temperature calendar treatment at 180 to 360 ° C. in a post-finishing process from the viewpoint of being easily made extremely thin. In particular, the so-called “soft calender” coated with a thermosetting resin or, in a high temperature range, a high temperature press with a calender composed of a steel roll / steel roll is preferably used for densification treatment. The thickness of the nonwoven fabric is preferably 60 μm or less.

  Although it does not specifically limit as heat resistant resin (binder) which comprises the said nonwoven fabric, It is preferable to make it equivalent to FR4 class by the PCT test etc. as solder heat resistance and a moisture resistance characteristic. For example, as described in JP-A No. 2002-30289, an epoxy resin emulsion and a blocked isocyanate resin are blended, or an amine adduct acidic neutralization solution of an epoxy resin described in JP-A No. 2002-317392 And the like obtained by impregnation.

The manufacturing method of the said nonwoven fabric is not specifically limited, A well-known method is employable. For example, the method described in Unexamined-Japanese-Patent No. 2002-317392 is mentioned.
Specifically, 20% by mass of a fine pulp-like product obtained by beating aramid fibers with a polyacrylamide / polyacrylic acid soda copolymer and a refiner as a sticking agent in ion-exchanged water, 1.5 denier 3 mm cut aramid fibers 80% by mass of fibers are dispersed in water, and paper is dehydrated to obtain a web. Next, it is sandwiched between nets and spray impregnated with a 10% concentration solution of epoxy binder, and then squeezed with mangles to homogenize, and dried with a cylinder dryer having a surface temperature of 135 ° C. of PTFE sheet adhesion. Next, it is densified and smoothed twice by passing through a steel / steel calendar having a surface temperature of 300 ° C. to obtain a nonwoven fabric.

  The method for embedding the above-described fibrous base material in the liquid coating film is not particularly limited. In the production method of the present invention, since the liquid coating film has a relatively low viscosity, it can be naturally embedded with the weight of the fibrous base material by placing the fibrous base material on the liquid coating film. However, when it is difficult to embed or to improve the efficiency of the work process, after placing the fibrous base material on the liquid coating film, pressure may be applied by a pressure roll or the like.

  In the manufacturing method of this invention, content of the said resin component is 40-75 mass% in the total 100 mass% of the said fiber base material and the resin component contained in the said thermosetting resin composition. Is preferable, it is more preferable that it is 45-70 mass%, and it is still more preferable that it is 47-60 mass%. When the ratio of the resin component is within this range, a homogeneous cured substrate free from bubbles can be obtained by thermo-pressure molding.

Next, the third step will be described.
In the third step, the fiber base material is embedded in the liquid coating film in the second step, and then solidified and integrated by volatilizing the volatile solvent in the liquid coating film, so that the fiber reinforced uncured film It is the process of obtaining. In the third step, the liquid coating is solidified by the evaporation of the solvent and integrated with the fibrous base material. In this way, a fiber reinforced uncured film is obtained. The obtained fiber reinforced uncured film has a strength enough to withstand handling by being cooled.
The obtained fiber-reinforced uncured film is in a so-called A stage or B stage and is in a state of flowing with heat before the cured C stage. That is, although the volatile solvent in the liquid coating film is evaporated and solidified, it is still in an uncured state, and is remelted by heating and exhibits adhesiveness. The obtained fiber-reinforced uncured film is considered to be in an A-stage state, most of which is uncured and has not been gelled.
The obtained fiber-reinforced uncured film may be used with the support carrier peeled off or may be used with the support carrier attached.

Examples of the method for volatilizing the volatile solvent include a method of heating with a hot air dryer, oven, infrared heater or the like.
The temperature at the time of heating needs to be appropriately changed depending on the difference in boiling point of the volatile solvent to be blended, the processing speed, and the like. That is, the temperature may be set so that the volatile solvent can be completely evaporated under the conditions that do not cause a curing reaction. The temperature at the time of heating varies depending on the type of solvent used and the like, and is preferably 60 to 120 ° C., for example. Moreover, after heating at 50-80 degreeC, it is more preferable to heat at 100-180 degreeC further.

  The thickness of the fiber reinforced uncured film is preferably 10 to 100 μm, more preferably 10 to 75 μm, and still more preferably 10 to 50 μm. If the thickness of the fiber reinforced uncured film is within this range, it can be made into an ultra-thin fiber reinforced uncured film. Since it becomes possible to make a coreless build-up printed wiring board, the electrical characteristics are drastically improved.

  The production method of the present invention further defoams the liquid coating film in which the fibrous base material is embedded in the second step between the second step and the third step. And a fourth step of smoothing the surface is one preferred embodiment. When this step is included, the obtained fiber-reinforced uncured film has fewer bubbles and is excellent in surface smoothness.

Examples of the method for defoaming and smoothing the surface by pressurizing the liquid coating film include a method using a pressure roll such as a roll nip.
The pressure roll is preferably an elastic roll coated with silicone rubber or a fluorine-based resin, and more preferably non-sticking to a solvent or a resin.
Although the pressure at the time of pressurizing is not specifically limited, 0.01-1.5 MPa is preferable and 0.2-1.2 MPa is more preferable from the point of defoaming and surface smoothing.

In the production method of the present invention, at least the surface in contact with the support carrier such as copper foil is in contact with a low-viscosity state containing a solvent. There is a big difference from the contact.
Since it is a fiber-reinforced uncured film that has been degassed in advance, it has the advantage that the transition from the A or B stage in the pressure press to the C stage of curing can be performed uniformly over the entire area. Further, the peel strength with the support carrier is higher, and the smoothness of the support carrier surface is excellent.

  In the production method of the present invention, the surface of the fiber-reinforced uncured film obtained in the third step further contains a thermosetting resin and a volatile solvent, and has a viscosity of 1000 mPa · s or less. It is one of the preferred embodiments that it has a fifth step of volatilizing the volatile solvent after applying the conductive resin composition. When this step is included, the fiber reinforced uncured film is more excellent in adhesion to the mating surface because the fiber surface can be embedded more completely, and there is no bare fiber portion on the film surface embedded with the fiber substrate. Can be obtained.

As the thermosetting resin composition used in the fifth step, the same thermosetting resin composition as described in the first step can be used.
Moreover, the application method of a thermosetting resin composition and the method of volatilizing a volatile solvent are the same as the method mentioned above.

  In the production method of the present invention described above, since the fibrous base material is embedded in a low-viscosity thermosetting resin composition containing a solvent, the thermosetting resin composition is easily impregnated in the fibrous base material. Therefore, it is difficult for bubbles to remain in the fiber-reinforced uncured film. In particular, when using a glass cloth that has been subjected to widening and flattening treatment, or when the content of the resin component in the thermosetting resin composition is in the specific range described above, it is more thermosetting in the fibrous base material. Since the resin composition is easily impregnated, bubbles can be reduced.

On the other hand, the dry laminating method described in Patent Document 4 embeds a glass cloth in an almost solid resin composition layer having a viscosity of about 1000 to 10000 Pa · s at 25 ° C. that does not contain a solvent. The viscosity of the resin composition layer is about 200 to 2000 times that of the liquid coating film of the production method of the present invention.
Therefore, it is necessary to heat-press, and in particular, the fiber reinforced uncured film with insufficient bubbles and insufficient penetration and penetration into the crossing portion of the fibers cannot be used.

Moreover, since the load with respect to a fibrous base material is small, the base material is not destroyed even if it uses the base material with comparatively weak intensity | strength. Therefore, the fiber reinforced uncured film can be thinned.
In particular, when the amount of the thermosetting resin composition to be attached to the fibrous base material is decreased by decreasing the resin concentration of the thermosetting resin composition, or an organic fiber nonwoven fabric whose strength is lowered by contact with a solvent is used. Even in this case, since the production method of the present invention has almost no load on the fibrous base material, the base material is not destroyed even when a base material having relatively low strength is used. On the other hand, in the manufacturing method using the conventional vertical coating apparatus, when the amount of the thermosetting resin composition to be adhered to the fibrous base material is increased, the weight of the resin composition or an excessive amount of the resin composition is rolled. Due to the increased load when scraping off, the fibrous base material tends to be broken, and it is difficult to use a base material with low strength.
In addition, the production method of the present invention accurately controls the resin impregnation amount, facilitates impregnation between filaments constituting the yarn bundle (voidless), does not destroy the fiber structure, and does not break the base material during impregnation. Excellent point.

Therefore, the fiber-reinforced uncured film of the present invention has no thickness unevenness and is sufficiently impregnated with resin between the filaments, and there are no bubbles in the film.
The fiber-reinforced uncured film of the present invention can have a thickness of, for example, 10 to 100 μm, preferably 10 to 75 μm, more preferably 10 to 50 μm. This is extremely useful in terms of enabling higher-density mounting.
Moreover, the fiber reinforced uncured film of the present invention is also excellent in surface smoothness.
Moreover, the fiber-reinforced uncured film of the present invention is excellent in adhesion between the support carrier and the resin.
Moreover, the fiber reinforced uncured film of the present invention is excellent in thickness accuracy.

  The fiber-reinforced uncured film of the present invention can be suitably used particularly for printed wiring laminates and adhesive sheets.

  The adhesive sheet of this invention is comprised with the fiber reinforced uncured film of this invention mentioned above. Therefore, there are few air bubbles, it can make thin, and it is excellent in surface smoothness and the adhesiveness of a support body carrier (in the case of metal foil) and resin. Moreover, the adhesive sheet of the present invention is excellent in heat resistance, moist heat resistance, chemical resistance, and reflow resistance, and has no defects such as powder falling and cracking.

  The adhesive sheet of the present invention can be used for industrial and electrical use, particularly for an adhesive sheet around a printed circuit board and on a copper foil surface.

  The laminate for printed wiring of the present invention has an insulating layer obtained by curing the fiber-reinforced uncured film of the present invention, and a conductor layer formed on at least one surface of the insulating layer.

The laminated board for printed wiring according to the present invention is, for example, a fiber reinforced uncured film having a conductor layer made of copper foil on the surface when copper foil is used as a support carrier in the method for producing a fiber reinforced uncured film of the present invention. Can be obtained by curing it by hot pressing or the like.
Further, when an organic film is used as a support carrier in the method for producing a fiber-reinforced uncured film of the present invention, after peeling the organic film from the obtained fiber-reinforced uncured film, one side or both sides of the fiber-reinforced uncured film A laminated sheet for printed wiring according to the present invention can be obtained by laminating a metal foil on the substrate and curing the fiber-reinforced uncured film by vacuum heating press or the like.

  As metal foil used for the said conductor layer, copper foil, aluminum foil, stainless steel foil etc. are mentioned, for example, Copper foil is preferable.

  The above-mentioned laminated board for printed wiring of the present invention is thin, excellent in smoothness, and has a low relative dielectric constant and dielectric loss tangent. Furthermore, it exhibits excellent performances such as high dimensional stability, high insulation reliability, high moisture resistance reliability, low dielectric constant, low dielectric loss tangent, solder heat resistance, flex resistance, chemical resistance, and migration resistance. Moreover, the laminate for printed wiring of the present invention can be processed without drilling smear by a laser processing machine such as a carbon dioxide laser, YAG laser, or excimer laser, and can also be processed in punching and drilling (φ20 to 1000 μm). .

Next, the electronic component of the present invention will be described.
The electronic component of the present invention is an electronic component obtained using the above-described laminated board for printed wiring of the present invention.
Preferred examples of the electronic component of the present invention include a printed wiring board. Among these, a printed wiring board obtained by a build-up method is more preferable. The build-up method is a method that meets the demands of the era of high-density mounting, and because of the thin film shape combined with the dielectric characteristics of the present invention, the entire package substrate is made thin instead of the thick core substrate, and further the core Since a build-up printed wiring board without a substrate is possible, the electrical characteristics are drastically improved.

The manufacturing method of the electronic component is not particularly limited, and can be obtained by a known manufacturing method. For example, a printed wiring board can be produced as follows.
First, the printed wiring laminate of the present invention is used, and the surface of the conductor layer of the printed wiring laminate is coated with a photosensitive resist. Then, this printed wiring laminate is introduced into an exposure machine, and exposure is performed by irradiating the photosensitive resist with light such as ultraviolet rays through a photomask. After the exposure as described above, development processing is performed to partially remove the photosensitive resist in a pattern opposite to the circuit pattern. Next, by performing an etching process, the conductive layer partially exposed by removing the photosensitive resist is dissolved in the etching solution and removed. After that, by peeling off the photosensitive resist, a printed wiring board having a circuit pattern formed on the surface with a conductor layer can be obtained.

  The electronic component of the present invention described above can be miniaturized and has a low relative dielectric constant and dielectric loss tangent. Furthermore, it exhibits excellent performances such as high dimensional stability, high insulation reliability, high moisture resistance reliability, low dielectric constant, low dielectric loss tangent, solder heat resistance, flex resistance, chemical resistance, and migration resistance.

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

<Preparation of thermosetting resin composition (varnish)>
(Formulation Examples 1 to 3)
The components shown in Table 1 below were mixed using a stirrer in the proportions (parts by mass) shown in Table 1 to obtain the compositions shown in Table 1.
About each obtained composition, the viscosity in 25 degreeC was measured using the E-type viscosity meter (TVE-22LT, the Toki Sangyo company make). The results are shown in Table 1 below.

The components in Table 1 are as follows.
・ Oligophenylene ether resin (reaction product of 2,2 ', 3,3', 5,5'-hexamethylbiphenyl-4,4'-diol-2,6-dimethylphenol polycondensate and chloromethylstyrene ): OPE-2st 2200, manufactured by Mitsubishi Gas Chemical Co., Ltd. SBS (styrene-butadiene-styrene block copolymer): TR2003 (trade name), manufactured by JSR, weight average molecular weight 100,000, styrene content 43%
Epoxy resin: YX6954BH30, manufactured by Japan Epoxy Resin Co., Ltd. Acetylated modified phenol novolak: Epicure DC808, manufactured by Japan Epoxy Resin Co., Ltd. Isocyanate compound (TDI block type polyisocyanate): Coronate 2507, manufactured by Nippon Polyurethane Co., Ltd. 2-ethyl-4 -Methylimidazole: 2E4MZ, manufactured by Shikoku Kasei Co., Ltd. 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate: Perocta-O, manufactured by NOF Corporation

<Fiber base material>
The base materials 1-4 shown below were prepared.
Base material 1: Glass cloth, 1000TF (trade name), manufactured by Asahi Schwer, in particular, warp yarns subjected to widening and flattening treatment

  Base material 2: Glass cloth, 101 (trade name), manufactured by Asahi Schwer

  Base material 3: Glass cloth, 1037 (trade name), manufactured by Asahi Schwer

Substrate 4: An aramid nonwoven fabric was produced according to the method described in Example 1 (Manufacture of nonwoven fabric for electrical insulation) of JP-A No. 2002-302893.
Specifically, poly-p-phenylene terephthalamide fiber (Kevlar, manufactured by DuPont) chop, poly-p-phenylene terephthalamide fiber pulp, and poly-m-phenylene isophthalamide fiber (second binder) Cornex, manufactured by Teijin Limited) was dispersed in water and mixed. All of these fibers have a fiber thickness of 1.5 denier and a fiber length of 3 mm. The poly-p-phenylene terephthalamide fiber pulp is obtained by beating the poly-p-phenylene terephthalamide fiber chop having a fiber length of 3 mm to have a freeness of 50 csf. The thermosetting resin binder to be applied is mainly composed of an epoxy resin emulsion (V coat A, manufactured by Dainippon Ink and Chemicals) and a blocked isocyanate resin (CR-60B, manufactured by Dainippon Ink and Chemicals), and the mass of the epoxy resin. The blended mass (curing agent mass) of the blocked isocyanate resin with respect to 10 was set to 1. This thermosetting resin binder was sprayed after making the fiber and dried by heating to produce a nonwoven fabric. Furthermore, this nonwoven fabric was heated and compressed by passing between a pair of heat rolls set to a linear pressure of 200 kN / m and a temperature of 333 ° C. This nonwoven fabric has a unit mass of 33 g / m ² , a thickness of 50 μm, and a blended mass ratio of poly-p-phenylene terephthalamide fiber chop and poly-p-phenylene terephthalamide fiber pulp (poly-p-phenylene terephthalamide fiber). Chop / poly-p-phenylene terephthalamide fiber pulp) 80/20, a thermosetting resin binder content in the nonwoven fabric of 17% by mass, and a second binder content in the nonwoven fabric of 8% by mass.

  The types of base materials 1 to 5, presence / absence of widening flattening treatment, thickness, unit mass, filament average diameter, apparent density, air permeability, fiber thickness, warp density and weft density are shown in Table 2 below.

<Manufacture of fiber reinforced uncured film>
(Examples 1 to 8: wet lamination method)
Thickness after curing using a gravure coater on a thermosetting resin composition (varnish) shown in Table 3 below on a PET film with a silicone release agent (Lumirror, manufactured by Toray Industries, Inc., thickness 38 μm, the same applies hereinafter) Was applied to give a liquid coating film of 2 to 90 μm. Next, the base material shown in Table 3 was placed on the liquid coating film, and the base material was embedded in the liquid coating film. Then, it heated at 60-120 degreeC for 1 to 5 minutes, the solvent in a liquid coating film was volatilized, resin and a base material were integrated, and the fiber reinforced uncured film was obtained.
Table 3 shows the amount of resin and the thickness of each fiber-reinforced uncured film obtained.

(Comparative Examples 1 to 5: a method using a conventional vertical coating apparatus)
Using a vertical coating apparatus, a PET film with a silicone release agent is impregnated with the thermosetting resin composition (varnish) shown in Table 3 below, and then pulled up in the vertical direction, and excess heat is generated at the roll nip. The curable resin composition was scraped off. Then, it heated at 150 degreeC for 3 to 10 minutes, the solvent in a thermosetting resin composition was volatilized, resin and a base material were integrated, and the fiber reinforced uncured film was obtained.
Table 3 shows the amount of resin and the thickness of each fiber-reinforced uncured film obtained.

(Comparative Examples 6 to 8: dry lamination method)
The thermosetting resin composition (varnish) shown in the following Table 3 is coated on a PET film with a silicone release agent (Lumirror, manufactured by Toray Industries, Inc., thickness 38 μm, the same applies hereinafter) using a die coater. After coating so that the thickness is as described in Table 3 below, the film of the thermosetting resin composition shown in Table 3 below is dried at 80 to 120 ° C. (average 100 ° C.) for 2 to 10 minutes. Film) was formed.
Next, the base material shown in Table 3 is placed on the surface of the dried film, heat-laminated for 1 to 20 seconds under the conditions of 50 ° C. and linear pressure of 2 kg / cm, and the resin and the base material are integrated. A fiber reinforced uncured film was obtained.
Table 3 shows the thickness of the uncured film and the amount and thickness of the resin in each of the obtained fiber-reinforced uncured films.

(Presence or absence of structural destruction of the base material)
The presence or absence of structural destruction of the base material in each fiber-reinforced uncured film obtained above was visually observed. Those with no structural destruction were marked with “◯”, and those with structural destruction were marked with “x”. The results are shown in Table 3.

(Measurement of thickness, relative permittivity, dielectric loss tangent after thermoforming)
Each of the fiber reinforced uncured films obtained above was cured under the following conditions and methods depending on the type of the thermosetting resin composition used. The thickness of the cured film was measured. The results are shown in Table 3.
Curing condition 1 (when the thermosetting resin compositions of Formulation Examples 1 and 2 are used): 200 ° C., 60 minutes, pressure of 1 MPa, vacuum pressure less than 10 kPa Curing condition 2 (thermosetting of Formulation Example 3) When resin composition is used): After pre-baking at 140 ° C. for 10 minutes, vacuum press at 180 ° C., 120 minutes, pressure 4 MPa, vacuum less than 10 kPa

  The cured film is cut into 10 cm × 4 cm, and a 10 cm long side is rolled into a 1 mm diameter cylinder so as to be in the length direction of the cylinder to obtain a sample. At 25 ° C., a cavity resonator (perturbation method) The dielectric constant and dielectric loss tangent were measured using a dielectric measuring device (manufactured by Kanto Electronics Application Development Co., Ltd.). The results are shown in Table 3.

(Surface roughness)
With a surface roughness measuring instrument (Surfcom 590A-12, manufactured by Tokyo Seimitsu Co., Ltd.), a 10-point average height Rz was determined at a measurement length of 30 mm and a measurement speed of 1.5 mm / s. The results are shown in Table 3.

(Coefficient of thermal expansion (CTE))
The cured film was cut into a width of 15 mm and a length of 40 mm, and this was used as a test piece. By using a thermal analyzer (TMA4000SA, manufactured by Bruker AXS), the heating rate was 5 ° C./min, and the tensile mode TMA method was used. The measurement was performed from 25 ° C to 250 ° C. The average expansion coefficient was determined from the slope of the linear expansion coefficient from 20 ° C to 150 ° C. The results are shown in Table 3.

(Elastic modulus and glass transition temperature (Tg))
The cured film was cut into a width of 10 mm and a length of 40 mm to obtain a test piece. Using this sample, a viscoelasticity spectrometer (model number EXSTAR6000 DMS, manufactured by Seiko Instruments Inc.) is used, and a storage elastic modulus at 25 ° C. is obtained by a DMA method with a grip width of 15 mm, a heating rate of 3 ° C./min, a frequency of 10 Hz, and a tensile mode. It was. Moreover, the glass transition temperature (Tg) was calculated | required from the storage elastic modulus of 25 degreeC, and the peak of dielectric loss tangent. The results are shown in Table 3.

<Manufacture of laminates>
A copper foil (electrolytic copper foil, thickness 18 μm, Rz 1.9 μm) was laminated on both surfaces of each of the fiber-reinforced uncured films obtained above, and vacuum heated and pressed under the following conditions to obtain a laminate.
Curing condition 1 (when the thermosetting resin compositions of Formulation Examples 1 and 2 are used): 200 ° C., 60 minutes, pressure of 1 MPa, vacuum pressure less than 10 kPa Curing condition 2 (thermosetting of Formulation Example 3) (When using a resin resin composition): After pre-baking at 140 ° C. for 10 minutes, vacuum press at 180 ° C., 120 minutes, pressure 4 MPa, degree of vacuum less than 10 kPa

(With or without voids)
The cross section of each obtained laminate was observed with a scanning electron microscope (SEM). The case where there was no void was designated as “◯”, and the case where there was a void as “x”. The results are shown in Table 3.

(Copper foil peel strength)
The copper foil of the laminated board obtained above was diced with a width of 10 mm according to JIS C6481-1996, and the copper foil was peeled off in the direction of 180 ° at a speed of 50 mm / min to obtain a peel strength. The results are shown in Table 3.

As is clear from the results shown in Table 3 above, in Comparative Examples 1 to 5 produced using a conventional vertical coating apparatus, the substrate was broken and air bubbles were also confirmed. Similarly, in Examples 6 to 8 produced by the dry laminating method, the base material was broken and air bubbles were also confirmed.
On the other hand, in Examples 1 to 8 produced by the wet laminating method of the present invention, the base material was not destroyed and bubbles were not confirmed. Moreover, it was a low dielectric constant and a low dielectric loss tangent, and the copper foil peel strength was high.

FIG. 1 is a schematic view showing a preferred example of the production method of the present invention. FIG. 2 is a schematic view showing another preferred example of the production method of the present invention. FIG. 3 is a schematic view showing an example of a method for producing a fiber-reinforced uncured film using a conventional vertical coating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber reinforced uncured film of this invention 3 Support carrier 5, 15 Coating apparatus 7 Liquid coating film 9 Fibrous base material 11 Pressure roll 13, 17 Drying furnace 31 Base material 32 Varnish 33 Roll nip

Claims (17)

A first step of applying a thermosetting resin composition containing a thermosetting resin and a volatile solvent and having a viscosity of 1000 mPa · s or less onto a support carrier to form a liquid coating film;
In the liquid coating film formed in the first step, the thickness is 8 to 100 μm, the air permeability is 5 to 200 cm ³ / cm ² / sec, and the apparent density is 0.5 to 1.5 g / second. a second step of burying a fibrous base material of cm ³ ;
After embedding the fibrous base material in the liquid coating film in the second step, the volatile solvent in the liquid coating film is volatilized and solidified to obtain a fiber-reinforced uncured film. The manufacturing method of the fiber reinforced uncured film which has a 3rd process.   The method for producing a fiber-reinforced uncured film according to claim 1, wherein the fibrous base material is a woven fabric or a nonwoven fabric configured using glass fibers or aramid fibers. The method for producing a fiber-reinforced uncured film according to claim ² , wherein the woven fabric formed using the glass fibers is composed of filaments having an average diameter of 3 to 9 μm and has a unit mass of 5 to 50 g / m ² .   The woven fabric composed of the glass fibers is composed of glass fibers whose filaments are relaxed by at least one type of fiber opening treatment selected from the group consisting of water jet treatment and widening flattening treatment. The method for producing a fiber-reinforced uncured film according to claim 2 or 3, which is a woven fabric.   The fiber-reinforced uncured film according to any one of claims 2 to 4, wherein the woven fabric formed using the glass fibers has a warp density of 40 to 100 yarns / inch and a weft yarn density of 25 to 100 yarns / inch. Manufacturing method. The non-woven fabric configured using the aramid fiber includes a fiber and a heat-resistant resin,
The fiber contains 50% by mass or more of paraphenylene terephthalamide fiber having a fiber thickness of 2 denier or less,
The content of the heat resistant resin in the nonwoven fabric is 5 to 30% by mass,
The method for producing a fiber-reinforced uncured film according to claim ² , wherein the nonwoven fabric has a unit mass of 20 to 80 g / m ² .   Content of the resin component in the said thermosetting resin composition is 5-45 mass%, The manufacturing method of the fiber reinforced uncured film in any one of Claims 1-6.   The content of the resin component is 40 to 75 mass% in a total of 100 mass% of the fibrous base material and the resin component contained in the thermosetting resin composition. The manufacturing method of the fiber reinforced uncured film of description.   The method for producing a fiber-reinforced uncured film according to any one of claims 1 to 8, wherein the thermosetting resin is a thermosetting oligophenylene ether resin and / or an epoxy resin having functional groups at both ends.   The thermosetting resin composition is derived from 100 parts by mass of thermosetting oligophenylene ether (A) having a styrene functional group at both ends having a number average molecular weight of 500 to 5,000 and a vinyl aromatic hydrocarbon monomer. The production of a fiber-reinforced uncured film according to claim 9, which is a thermosetting resin composition containing 50 to 250 parts by mass of a block copolymer (B) containing a unit and a repeating unit derived from a conjugated diene monomer. Method. A linear epoxy resin (C) having a weight average molecular weight of 1,500 to 70,000, wherein the thermosetting resin composition has one or more hydroxy groups and two or more epoxy groups;
An epoxy resin composition containing a modified phenol novolak (D) obtained by esterifying at least a part of a phenolic hydroxy group with a fatty acid,
The method for producing a fiber-reinforced uncured film according to claim 9, wherein the content of the modified phenol novolac (D) is 30 to 200 parts by mass with respect to 100 parts by mass of the linear epoxy resin (C).   The method for producing a fiber-reinforced uncured film according to claim 11, wherein the epoxy resin composition further contains an isocyanate compound.   The method for producing a fiber-reinforced uncured film according to claim 11 or 12, wherein the epoxy resin composition further contains divinylbenzene.   Content of the resin component in the said thermosetting resin composition is 10-40 mass%, The manufacturing method of the fiber reinforced uncured film in any one of Claims 1-13.   The method for producing a fiber-reinforced uncured film according to claim 1, wherein the fiber-reinforced uncured film has a thickness of 10 to 120 μm.   Furthermore, between the second step and the third step, the liquid coating film in which the fibrous base material is embedded in the second step is pressurized to defoam and smooth the surface. The manufacturing method of the fiber reinforced uncured film in any one of Claims 1-15 which has four processes.   Furthermore, a thermosetting resin composition containing a thermosetting resin and a volatile solvent and having a viscosity of 1000 mPa · s or less was applied to the surface of the fiber-reinforced uncured film obtained in the third step. The method for producing a fiber-reinforced uncured film according to claim 1, further comprising a fifth step of volatilizing the volatile solvent.

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