JP2006179888A - Interlayer film for printed-wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interlayer film for a printed-wiring board that ensures adhesiveness between insulating resin and a conductor while maintaining dimensional stability of the printed-wiring board. <P>SOLUTION: An interlayer film for a printed-wiring board has on a supporting base film, the interlayer film that has a high-viscosity layer (A) composed of curable resin compositions (JA), and a low-viscosity layer (B) composed of curable resin compositions (JB). The curable resin compositions (JA) and curable resin compositions (JB) meet specific conditions regarding the complex viscosity and inorganic filler content. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an interlayer film for a printed wiring board.

As an insulating material used for manufacturing a multilayer printed wiring board by build-up, a material (insulating resin) excellent in dimensional stability is required from the viewpoint of reliability. A technique for reducing the thermal expansion coefficient and improving the dimensional stability by containing a filler is known, and it is known that the dimensional stability improves as the filler content increases (for example, Patent Documents 1 to 3). 3).
JP-A-6-120626 JP-A-6-196856 JP 2000-88671 A

However, the conventional insulating resin improves the dimensional stability when the filler content is increased, but the surface roughness after roughening decreases and the rough surface resin strength also decreases, so the adhesion between the insulating resin and the conductor is reduced. There is a problem that sex cannot be secured. In the additive method (method of applying a conductor by plating), it is very important from the viewpoint of reliability that the surface of the insulating resin to which the conductor is applied can be roughened and the adhesion between the insulating resin and the conductor can be secured.
An object of the present invention is to provide an interlayer film for a printed wiring board that maintains the dimensional stability of the printed wiring board and ensures adhesion between an insulating resin and a conductor.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention has a high viscosity layer (A) composed of a curable resin composition (JA) and a low viscosity layer (B) composed of a curable resin composition (JB) on a support base film,
The gist is that the curable resin composition (JA) and the curable resin composition (JB) are made of an interlayer film for a printed wiring board that satisfies the conditions (1) and (2).
(1) The complex viscosity of the curable resin composition (JA) is 60 to 5,000 Pa · s, the complex viscosity of the curable resin composition (JB) is 50 to 1,000 Pa · s, and the curable resin composition. The optimum flow temperature (T) at which the complex viscosity of the product (JA) is 1.2 to 100 times the complex viscosity of the curable resin composition (JB) is 70 to 130 ° C.
(2) The curable resin composition (JA) and the curable resin composition (JB) contain an inorganic filler, and the content of the inorganic filler in the curable resin composition (JA) is the curable resin composition (JA). The content of the inorganic filler of the curable resin composition (JB) is 35 to 75% by weight based on the weight of the curable resin composition (JB). In addition, after laminating the film on the patterned inner layer circuit board at the optimum flow temperature (T), the support base film is peeled off as necessary (1), the curable resin composition (JA), and curing. After heat-curing the curable resin composition (JB), a step (2) of roughening the cured surface of the curable resin composition (JA) with an oxidizing agent, and a conductor on the roughened cured surface by plating It is a manufacturing method of a printed wiring board including the process (3) of forming.

The interlayer film for printed wiring boards of the present invention has the following effects.
(1) When laminated on a substrate having a through hole or a surface via hole, the curable resin composition (JB) is filled in the through hole or the surface via hole, and the entire surface is covered with the curable resin composition (JA). In addition, since these can be performed at the same time, the productivity of the printed wiring board is excellent.
(2) The adhesiveness between the insulating resin and the conductor can be secured while maintaining the dimensional stability of the printed wiring board.

The interlayer film for a printed wiring board of the present invention comprises a high viscosity layer (A) made of a curable resin composition (JA) and a low viscosity layer (B) made of a curable resin composition (JB) on a support base film. ).
Furthermore, you may have another layer other than these layers (A, B). And as a structure of a layer, it is preferable to provide so that a high-viscosity layer (A) may be pinched | interposed between a support base film and a low-viscosity layer (B). That is, the support base film, the high viscosity layer (A), and the low viscosity layer (B) are preferably arranged in this order. Here, the curable resin composition refers to a composition containing a curable resin and substantially not containing an organic solvent.
The maximum flow temperature (T; ° C.) is preferably 70 to 130, more preferably 80 to 120, and particularly preferably 90 to 110. Within this range, the film is not sticky at around room temperature (about 25 to 30 ° C.), so that it is easy to handle and the smoothness after curing of the curable resin composition is excellent.
Here, the optimal flow temperature (T) is that the complex viscosity of the curable resin composition (JA) is 60 to 5,000 Pa · s, and the complex viscosity of the curable resin composition (JB) is 50 to 1,000 Pa. S, and the temperature at which the complex viscosity of the curable resin composition (JA) is 1.2 to 100 times the complex viscosity of the curable resin composition (JB), which is a value obtained by the method described later. .

  The complex viscosity at the optimum flow temperature (T) of the curable resin composition (JA) is 60 to 5, from the viewpoint of covering the entire surface of the substrate having through holes or surface via holes with the curable resin composition (JA). 000 Pa · s is preferable, more preferably 80 to 4,500 Pa · s, particularly preferably 100 to 4,000 Pa · s, and most preferably 150 to 3,500.

In the present invention, the complex viscosity [Pa · s] is a complex shear viscosity measured according to JIS K-7244-10: 2005, for example, a viscoelasticity measuring device (for example, manufactured by Rheometric Scientific). ARES). The measurement method of the viscoelasticity measuring device mentioned here is a method for measuring viscoelasticity when rotating shear stress is applied to a measurement sample. The measurement sample has a thickness of 0.500 mm (for example, 20 layers of a film made of a curable resin composition (JA) or a curable resin composition (JB) having a thickness of 40 μm on a sample fixing jig). The thickness is set to 0.800 mm, and the sample is pressed with the temperature adjusted to 50 ° C. and compressed to a thickness of 0.500 mm), and cut into a circle with a diameter of 25 mm.
The complex viscosity is obtained by sandwiching a measurement sample between two disk-shaped sample fixing jigs held in parallel with a specific gap (distance between the disks). By rotating at a specific frequency with the center as the axis, a rotational shear stress is applied in the circumferential direction of the disk. The applied rotational shear stress is sine-vibrated with an amplitude of 2 × 10 ⁻³ [rad] and applied.

The measurement conditions are shown below.
Sample fixing jig: 25 mm diameter aluminum disk (for example, ARES-DP25A manufactured by Rheometric Scientific)
Sample: Distance between disk-shaped gaps with a diameter of 25 mm and a thickness of 0.500 mm: 0.500 mm
Rotational shear stress amplitude: 2 × 10 ⁻³ [rad]
Sine rotation shear stress frequency: 1.5915Hz
Temperature increase rate: After holding at 50 ° C. for 20 minutes, the temperature is increased from 50 ° C. to 150 ° C. at a rate of 10 ° C./min.
The temperature and complex viscosity are read from the time (temperature) -complex viscosity curve obtained by the measurement. The complex viscosity of the curable resin composition (JA) is 60 to 5,000 Pa · s, the complex viscosity of the curable resin composition (JB) is 50 to 1,000 Pa · s, and the curable resin composition. The temperature at which the complex viscosity of (JA) is 1.2 to 100 times the complex viscosity of the curable resin composition (JB) is defined as the optimum flow temperature (T). Note that the optimum flow temperature (T) may have a certain numerical range as well as a single value.

  The complex viscosity at the optimum flow temperature (T) of the curable resin composition (JB) is 50 to 1,000 Pa · s from the viewpoint of the ability of the curable resin composition (JB) to enter the through hole or the surface via hole. It is preferably 60 to 900 Pa · s, more preferably 70 to 800 Pa · s, and most preferably 90 to 400 Pa · s.

  Moreover, although the interlayer film for printed wiring boards of this invention consists of a support base film, a high-viscosity layer (A), and a low-viscosity layer (B), at least one of a high-viscosity layer (A) and a low-viscosity layer (B) May have a multilayer structure. For example, as the high viscosity layer (A), a high viscosity layer (A1) composed of a curable resin composition (JA1) and a high viscosity layer (JA2) composed of a curable resin composition (JA2) having a complex viscosity different from the complex viscosity ( A2) or a curable resin composition having a complex viscosity different from the low viscosity layer (B1) composed of the curable resin composition (JB1) and the low viscosity layer (B). The thing comprised from the low-viscosity layer (B2) which consists of a thing (JB2) can be used. In such a case, curable resin composition (JA) {curable resin composition (JA1) or curable resin composition (JA2)} and curable resin composition (JB) {curable resin composition (JB1) Or, any combination with the curable resin composition (JB2)} preferably satisfies the above conditions (1) and (2). As an example of such a multilayer structure, the structure etc. which are laminated | stacked in order of a support base film-high viscosity layer (A1) -high viscosity layer (A2) -low viscosity layer (B1) -low viscosity layer (B2), etc. are mentioned. . In this case, the complex viscosity is preferably decreased in the order of the high viscosity layer (A1), the high viscosity layer (A2), the low viscosity layer (B1), and the low viscosity layer (B2). The same applies when the high-viscosity layer (A) or the low-viscosity layer (B) has a multilayer structure composed of three or more layers. In this case, the through hole or the surface via hole is excellent in filling property, and it is suitable for covering the entire inner layer circuit board surface.

From the viewpoint of allowing the curable resin composition (JB) to enter the through hole or the surface via hole and covering the entire surface of the inner circuit board with the curable resin composition (JA), the optimum flow temperature (T) The complex viscosity of the curable resin composition (JA) in is preferably 1.2 to 100 times, more preferably 1.4 to 95 times the complex viscosity of the curable resin composition (JB) at the same temperature. Especially preferably, it is 1.6 to 90 times.
Here, when at least one of the curable resin composition (JA) and the curable resin composition (JB) is composed of multiple layers, the complex viscosity of the curable resin composition (JA) is that of the curable resin composition (JA). Among them, the value of the curable resin composition (JA) that forms the highest viscosity layer, the complex viscosity of the curable resin composition (JB) is the lowest viscosity layer of the curable resin composition (JB). Each value of the curable resin composition (JB) to be formed is used.

As a method of increasing the complex viscosity of the curable resin composition (JA) and the curable resin composition (JB), a method of increasing the molecular weight of the curable resin (for example, epoxy resin), and increasing the inorganic filler content Methods and the like. On the other hand, examples of the method for reducing the complex viscosity include a method for lowering the molecular weight of the curable resin and a method for reducing the inorganic filler content.
Examples of the method for increasing the optimum flow temperature (T) include a method for increasing the molecular weight of the curable resin and a method for increasing the inorganic filler content. On the other hand, examples of a method for lowering the optimum flow temperature (T) include a method for lowering the molecular weight of the curable resin and a method for reducing the inorganic filler content.
The ratio of the complex viscosity of the curable resin composition (JA) and the curable resin composition (JB) at the optimum flow temperature (T) {viscosity ratio of the condition (1): 1.2 to 100} It is possible to easily adjust by combining.

  The curable resin composition (JA) and the curable resin composition (JB) each preferably contain an inorganic filler. In the case of the curable resin composition (JA), the content of the inorganic filler is 5 to 5 based on the weight of the curable resin composition (JA) from the viewpoint of adhesion between the resin after the roughening and the conductor. It is preferably 45% by weight, more preferably 7 to 42% by weight, particularly preferably 10 to 40% by weight, and most preferably 13 to 36% by weight. Further, in the case of the curable resin composition (JB), the content of the inorganic filler is from 35 to the weight of the curable resin composition (JB) from the viewpoint of smoothness around the through hole or surface via hole opening. It is preferably 75% by weight, more preferably 38 to 70% by weight, particularly preferably 40 to 65% by weight, and most preferably 43 to 60% by weight.

The curable resin composition (JA) and the curable resin composition (JB) are preferably thermosetting resin compositions. A thermosetting resin composition is comprised from a thermosetting resin, an inorganic filler, and other components (roughening component etc.) as needed.
Examples of the thermosetting resin contained in the thermosetting resin composition include epoxy resins, polyimide resins, and resins having other reactive groups.
Examples of such a thermosetting resin include an epoxy resin described in JP-A-2001-279116, a polyimide resin described in JP-A-2002-88242, and other resins described in JP-A-2001-279110. A resin having a reactive group can be used. Here, the other reactive group includes functional groups described in paragraph 0014 of JP-A-2001-279110. Among these, an epoxy resin is preferable, and an epoxy resin having two or more epoxy groups in the molecule is more preferable.

  As the epoxy resin having two or more epoxy groups in the molecule, the above-mentioned known ones can be used, for example, glycidyl ether type epoxide, glycidyl ester type epoxide, glycidyl amine type epoxide and alicyclic epoxide are used. it can.

Examples of the glycidyl ether type epoxide include glycidyl ether of dihydric phenol, glycidyl ether of polyhydric phenol, glycidyl ether of dihydric alcohol, and glycidyl ether of polyhydric alcohol.
Examples of the glycidyl ether of dihydric phenol include bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, and bisphenol S diglycidyl ether.
Examples of the glycidyl ether of polyhydric phenol include dihydroxynaphthyl cresol triglycidyl ether, tris (hydroxyphenyl) methane triglycidyl ether, dinaphthyltriol triglycidyl ether, phenol novolac polyglycidyl ether and cresol novolac polyglycidyl ether.
Examples of the glycidyl ether of dihydric alcohol include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol [weight average molecular weight (hereinafter, Mw): 150-4,000] diglycidyl ether and polypropylene glycol (Mw: 180-5,000) diglycidyl ether.
Examples of the glycidyl ether of polyhydric alcohol include trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol hexaglycidyl ether and poly (degree of polymerization 2 to 5) glycerin polyglycidyl ether.

As the glycidyl ester type epoxide, glycidyl ester of carboxylic acid, glycidyl ester type polyepoxide and the like are used.
Examples of glycidyl esters of carboxylic acid include glycidyl (meth) acrylate, diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, and triglycidyl ester of trimellitic acid.

Examples of the glycidylamine type epoxide include glycidyl aromatic amine, glycidyl alicyclic amine, and glycidyl heterocyclic amine.
Examples of glycidyl aromatic amines include N, N-diglycidylaniline, N, N-diglycidyltoluidine, N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane, N, N, N ′, N′-tetraglycidyl. Examples include diaminodiphenyl sulfone and N, N, N ′, N′-tetraglycidyl diethyldiphenylmethane.
Examples of glycidyl alicyclic amines include bis (N, N-diglycidylaminocyclohexyl) methane (hydrogenated compound of N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane) and N, N, N ′, N ′. -Tetraglycidyl dimethylcyclohexylenediamine (hydrogenated compound of N, N, N ', N'-tetraglycidylxylylenediamine) and the like.
Examples of the glycidyl heterocyclic amine include trisglycidylmelamine and N-glycidyl-4-glycidyloxypyrrolidone.

  Alicyclic epoxides include vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide, bis (2,3-epoxycyclopentyl) ether, ethylene glycol bisepoxy dicyclopentyl ether and 3,4-epoxy-6-methyl. Examples include cyclohexylmethyl 3 ′, 4′-epoxy-6′-methylcyclohexanecarboxylate.

  Among these epoxy resins, glycidyl ether type epoxides, glycidyl ester type epoxides and glycidyl amine type epoxides are preferable, and glycidyl ether type epoxides and glycidyl ester type epoxides are more preferable, from the viewpoints of price and heat resistance. These epoxy resins may be used alone or in combination of two or more selected from these.

The number of epoxy groups in the epoxy resin is preferably 2 or more in number average in the molecule, more preferably 2 to 500, next preferably 3 to 300, and particularly preferably 4 to 100. When the number of epoxy groups is within this range, the thermal shock resistance and dielectric properties of the curable resin composition are further improved.
The Mw of the epoxy resin is preferably 300 to 10,000, more preferably 400 to 9,000, particularly preferably 500 to 5,000, from the viewpoint of thermal shock resistance and the like.
In the present invention, the weight average molecular weight (Mw) is measured by a gel permeation chromatography method (for example, measured as follows).
Apparatus: HLC-802A (Tosoh Corporation)
Column: Column with TSK gel GMH6 × 2 (Tosoh Corporation) connected in series Column temperature: 40 ° C.
Developing solvent: THF (special grade reagent)
Sample concentration: 0.25% by weight
Injection volume: 10 μl
Flow rate: 1.0 (ml / min)
Detector: Differential refractive index detector Standard material: Standard polystyrene (molecular weight: 842,000, 488,000, 28,990, 1.09 million, 35,000, 190,000, 964,000, 37,000, 196,000, 9.1,000, 2.988,000, 870, 500)

The epoxy resin can contain a ring-opening polymerization catalyst, a curing agent, a curing accelerator, and the like.
As the ring-opening polymerization catalyst, known catalysts can be used, and imidazole, tertiary amines and salts thereof can be used.
Examples of imidazole include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole and 1-cyanoethyl-2- And methyl imidazole.
Tertiary amines include benzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, 2,4,6-tris (dimethylamino) phenol, triethylamine, and 1,4. And 8-diazabicyclo [5,4,0] -7-undecene.
Examples of these salts include organic acid (such as fatty acids having 1 to 30 carbon atoms) salts and inorganic acid (such as hydrochloric acid and sulfuric acid) salts. An organic acid salt is preferable, a fatty acid salt having 1 to 30 carbon atoms is more preferable, and 2-ethylhexanoic acid salt is particularly preferable.
When this ring-opening polymerization catalyst is contained, this addition amount (% by weight) is based on the weight of the curable resin composition {curable resin composition (JA) or curable resin composition (JB)} made of an epoxy resin. Based on this, it is preferably 0.1 to 10, more preferably 0.3 or more, particularly preferably 0.5 or more, more preferably 7 or less, and particularly preferably 5 or less.

As the curing agent, known ones (for example, “Practical Plastic Dictionary”, Industrial Research Council, Inc., published on May 1, 1993, described on pages 218 to 219) and the like can be used. Acid anhydrides, amine compounds, phenol compounds and the like can be used.
As the carboxylic acid, aromatic carboxylic acid and alicyclic carboxylic acid are used.
Examples of the aromatic carboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and trimellitic acid.
Examples of the alicyclic carboxylic acid include cyclohexane-1,2-dicarboxylic acid (phthalic acid aromatic nucleus hydrogenated compound) and cyclohexane-1,3-dicarboxylic acid (isophthalic acid aromatic nucleus hydrogenated compound).
Examples of the acid anhydride include phthalic anhydride, maleic anhydride, 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, and the like.

As the amine compound, an aromatic amine compound, an aliphatic amine compound, an alicyclic amine compound, or the like is used.
Examples of the aromatic amine compound include 1,3-phenylenediamine, 1,4-phenylenediamine, and 4,4′-diphenylmethanediamine.
Examples of the aliphatic amine compound include ethylenediamine, propylenediamine, trimethylenediamine, diethylenetriamine, and iminobispropylamine.
Examples of the alicyclic amine compound include cyclohexylene-1,3-diamine (an aromatic nucleus hydrogenated compound of 1,3-phenylenediamine), cyclohexylene-1,4-diamine (an aromatic nucleus water of 1,4-phenylenediamine). Additive compound), bis (aminocyclohexyl) methane (hydrogenated compound of an aromatic nucleus of 4,4′-diphenylmethanediamine), and the like.

Examples of the phenol compound include cresol novolak resin (Mw: 320 to 32,000), phenol novolak resin (Mw: 360 to 36,000), naphthylcresol, tris (hydroxyphenyl) methane, dinaphthyltriol, tetrakis (4- Hydroxyphenyl) ethane and 4,4′-oxybis (1,4-phenylethyl) tetracresol.
Of these curing agents, phenol compounds are preferred from the viewpoint of reliability (heat resistance, storage stability, etc.).
These curing agents may be used alone or in combination of two or more.

When the curing agent is contained, this content is 0.7 to 1.3 as an equivalent ratio of the epoxy resin and the curing agent (epoxy group / molar ratio of a functional group capable of reacting with an epoxy group in the curing agent). Is preferable, more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1. Within this range, the glass transition temperature (Tg) of the cured product is further increased, and the strength of the cured product is further unlikely to decrease.
Here, examples of the functional group capable of reacting with an epoxy group include an amino group, a phenolic hydroxyl group, a 1,3-dioxo-2-oxapropylene group, and a carboxy group.

As a hardening accelerator, the same thing as said ring-opening polymerization catalyst can be used.
The addition amount (% by weight) of the curing accelerator is 0.01 to based on the weight of the curable resin composition {curable resin composition (JA) or curable resin composition (JB)} made of an epoxy resin. 10 is preferable, more preferably 0.05 to 7, and particularly preferably 0.1 to 5.

It is desirable to add a polymer epoxy resin to these epoxy resins from the viewpoint of thermal shock resistance and the strength of the cured film. As the polymer epoxy resin, one having at least two epoxy groups in the molecule is preferable. The glass transition temperature (° C) before curing of the polymer epoxy resin is preferably 50 to 150, more preferably 55 to 140, and particularly preferably 60 to 130. The Mw of the polymer epoxy resin is preferably 10,000 to 1,000,000, more preferably 15,000 to 800,000, and particularly preferably 20,000 to 600,000. Within these ranges, the thermal shock resistance and the strength of the cured film are further improved.
When the polymer epoxy resin is contained, this content (% by weight) is determined by the curable resin composition comprising the epoxy resin containing the polymer epoxy resin {the curable resin composition (JA) or the curable resin composition ( JB)} is preferably 2 to 70, more preferably 5 to 50, and particularly preferably 10 to 30. Within this range, the strength of the interlayer film is further improved, and the lamination of the interlayer film is further facilitated. When the content of the polymer epoxy resin is increased, the viscosity of the curable resin composition tends to increase.

As the polymer epoxy resin, known ones described in JP-A-2001-279116 can be used, and a styrene / glycidyl (meth) acrylate copolymer (Mw: 2,000 to 500,000, styrene: 5). -95 wt%), styrene / glycidyl (meth) acrylate / alkyl (C1-12) (meth) acrylate (Mw: 2,000-500,000, styrene: 5-95 wt%, alkyl (meth) acrylate : 1 to 40% by weight) copolymers and glycidyl ester type polyepoxides such as polyglycidyl (meth) acrylate.
Of these polymer epoxy resins, a styrene / glycidyl methacrylate copolymer and a styrene / glycidyl methacrylate / alkyl (meth) acrylate copolymer are preferable from the viewpoint of cost, reliability, and dielectric properties.

Inorganic fillers that can be contained in the curable resin composition are classified into inorganic oxides and inorganic salts. Known inorganic oxides can be used as the inorganic oxide, and examples include titanium oxide, silicon oxide, and aluminum oxide.
As an inorganic salt, a well-known thing etc. can be utilized and a calcium carbonate, barium sulfate, etc. are mentioned.
Among these, inorganic oxides are preferable from the viewpoint of electrical characteristics (wet heat reliability, dielectric characteristics, etc.), heat resistance and chemical resistance, and silicon oxide and titanium oxide are more preferable, and silicon oxide is particularly preferable. .

  The volume average particle diameter (μm) of these inorganic fillers is preferably 0.01 to 50, more preferably 0.02 to 30, particularly preferably 0.03 to 20, and most preferably 0.05 to 10. . When the volume average particle diameter (μm) of the inorganic filler is within this range, the complex viscosity and the linear expansion coefficient of the curable resin composition are appropriate, which is preferable.

  In the present invention, the volume average particle diameter can be measured by a laser diffraction method based on JIS Z8825-1: 2001. LA-700 (manufactured by Horiba, Ltd.) is used as the measuring device, batch cell is used as the cell, and methyl ethyl ketone is used as the solvent, and the transmittance is measured in the range of 70 to 90%. The refractive index setting is appropriately determined according to the type of filler according to the manual attached to the device. For example, in the case of silicon oxide (silica), the refractive index is measured using 1.1.

In addition, from the viewpoint of efficiently performing wet roughening (chemical treatment) on the surface of the film after heat curing the interlayer film, the curable resin composition (JA) is roughened soluble in an oxidizing agent. It is preferable to contain a component.
Examples of the roughening component soluble in the oxidizing agent include rubber, amino resin, inorganic filler, and organic filler.
In the present invention, the term “soluble in an oxidizing agent” means a property capable of being dissolved in water or an organic solvent by being oxidatively decomposed by an oxidizing agent.
Examples of the oxidant-soluble organic filler include epoxy resins and cross-linked acrylic polymers.
Examples of the oxidant-soluble rubber include polybutadiene rubber, epoxy-modified, urethane-modified, various modified polybutadiene rubbers such as (meth) acrylonitrile modification, and (meth) acrylonitrile-butadiene rubber and acrylic rubber-dispersed epoxy containing a carboxyl group. Examples thereof include resins.

Examples of oxidant-soluble amino resins include melamine resins, guanamine resins, urea resins, and alkyl etherified resins thereof.
Examples of the oxidant-soluble inorganic filler include calcium carbonate, magnesium carbonate, and magnesium oxide.
Examples of the oxidant-soluble organic filler include a powder epoxy resin and a crosslinked acrylic polymer, and those obtained by thermally curing the amino resin and then finely pulverizing it.
When these oxidizing agent-soluble roughening components are contained, the content is preferably 3 to 40% by weight, more preferably 5 to 35% by weight, based on the weight of the curable resin composition (JA). It is. Within this range, the roughening property is sufficient, and the interlayer insulating material has good electrical characteristics, chemical resistance and heat resistance.

The curable resin composition {curable resin composition (JA) and curable resin composition (JB)} in the present invention may further contain an additive as necessary. Examples of the additive include a flame retardant, a thickener, and a leveling agent.
As the flame retardant, known flame retardants (such as those described in the above-mentioned patent publications) such as phosphorus-containing flame retardants and halogen-containing flame retardants can be used.
Examples of phosphorus-containing flame retardants include trialkyl (alkyl group having 1 to 12 carbon atoms) phosphate (trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxy phosphate, etc.) and triaryl phosphate (triphenyl phosphate, etc.) Is mentioned.
Examples of halogen-containing flame retardants include hexachloropentadiene, hexabromodiphenyl, octabromodiphenyl oxide, tribromophenoxymethane, decabromodiphenyl, decabromodiphenyl oxide, tetromophthalimide, hexabromobutene and hexabromocyclododecane. .
In the case of using a flame retardant, the content (% by weight) of the flame retardant is determined from the viewpoint of exhibiting flame retardancy, curable resin composition {curable resin composition (JA) or curable resin composition (JB). } Is preferably 0.5 to 30, more preferably 1 to 15, and particularly preferably 2 to 10.
As the thickener, known thickeners such as asbestos and benton (such as those described in the above-mentioned patent publications) can be used. When a thickener is used, the content (% by weight) of the thickener is based on the weight of the curable resin composition {curable resin composition (JA) or curable resin composition (JB)}. 0.01-5 are preferable, More preferably, it is 0.1-4, Most preferably, it is 0.5-3.

  As the leveling agent, known leveling agents such as silicone leveling agents, polyether leveling agents, and alcohol leveling agents can be used. When a leveling agent is used, the content of the leveling agent is 0.01 to 10 based on the weight of the curable resin composition {curable resin composition (JA) or curable resin composition (JB)}. More preferably, it is 0.1-7, Most preferably, it is 0.5-5.

The curable resin composition (JA) and the curable resin composition (JB) are obtained by uniformly mixing the curable resin and, if necessary, the filler and other additives described above with a known mixing apparatus. As temperature (degreeC) at the time of uniformly mixing, Preferably it is 0-150, More preferably, it is 10-130, Most preferably, it is 20-110, Most preferably, it is 30-100. Any mixing device can be used without limitation as long as it can mix a filler with a liquid material. For example, a planetary mixer, a bead mill, three rolls, and two rolls can be used.
The stirring and mixing time is, for example, the time until most of the aggregates contained in the filler disappear (for example, determined while measuring the particle size distribution), etc., and is appropriately determined. If necessary, coarse particles and the like may be removed from the mixture obtained by mixing in this way by filtration. The complex viscosity of the curable resin composition (JA) and the curable resin composition (JB) obtained in this way satisfies the above-mentioned viscosity characteristics.

The interlayer film for a printed wiring board of the present invention is a known curable resin composition (JA) resin varnish dissolved or dispersed in an organic solvent using a base film as a support, such as curtain coating, roll coating, spray coating, or screen printing. After coating using the above method, the solvent is dried by heating and / or hot air blowing to obtain a solid at room temperature. The drying conditions vary depending on the solvent to be used, but it is preferably carried out at 50 to 150 ° C. for 2 to 30 minutes, and is appropriately determined based on the complex viscosity of the curable resin composition obtained after drying, the residual solvent amount (% by weight), and the like. To do. Furthermore, after apply | coating the resin varnish of the curable resin composition (JB) melt | dissolved or disperse | distributed to the organic solvent on it, it can create by drying a solvent on the conditions similar to the above by heating and / or hot air spraying.
Examples of the base film include polyolefin such as polyethylene and polyvinyl chloride, polyester such as polyethylene terephthalate, and polycarbonate. The thickness of the base film is preferably 10 to 150 μm. The width of the base film is not particularly specified as long as it can enter the apparatus, but is preferably 30 to 300 cm.
The base film may be subjected to a mold release treatment in addition to a mat treatment and a corona treatment. Since the resin composition oozes out when laminating, it is easy to prevent the resin from adhering to the laminated part and to peel off the supporting base film if a supporting base part having no resin is provided at both ends or one side of the roll. There are advantages such as. Therefore, it is preferable not to apply the curable resin composition to the end portion 5 mm of the base film. In the present invention, when the base film is a resin support layer, the base film is referred to as a support base film.

  As the organic solvent, the curable resin composition (JA) or the curable resin composition (JB) can be dissolved or dispersed, and the resin solution can be adjusted to physical properties (viscosity, etc.) applicable to the film manufacturing apparatus. Any known solvent can be used without limitation, for example, N-methylpyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone and xylene. Among these solvents, those having a boiling point of 200 ° C. or lower (toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone, xylene, etc.) are preferable from the viewpoint of the drying temperature of the film. These can also be used individually or in combination of 2 or more types.

  The residual solvent amount (% by weight) after drying of the interlayer film for printed wiring board of the present invention is the resin penetration into the through hole or surface via hole and the handling of the interlayer film for printed wiring board (film cracking). From the viewpoint of the above, based on the weight of the interlayer film for printed wiring boards, 0.1 to 5.0 is preferable, more preferably 0.2 to 4.0, and particularly preferably 0.3 to 3.0. . When the residual solvent amount is 5.0% by weight or less, voids or the like hardly occur in the through hole or the surface via hole when the resin is cured, and when it is 0.1% by weight or more, the interlayer for the printed wiring board Excellent handling characteristics of the film (the film is difficult to break).

The residual solvent amount is measured by the following method.
An interlayer film for printed wiring board (before curing) is cut out to 10 cm × 10 cm together with the supporting base film as a measurement sample, and this weight (W1) is measured. The weight (W2) of a separately prepared 10 cm × 10 cm support base film is measured. The measurement sample is dried for 10 minutes in a circulating dryer at 130 ° C. The weight (W3) of the measurement sample after drying is measured, and the value calculated from the following equation (i) is obtained. The average value of five measurements is defined as the residual solvent amount.
[1- (W3-W2) / (W1-W2)] × 100 [%] (i)

The thickness of the low-viscosity layer (B) after being applied to the support base film and dried (that is, the thickness of the low-viscosity layer (B) as an interlayer film for a printed wiring board) is greater than the conductor thickness of the laminated inner circuit board Preferably, the range of conductor thickness + (10 to 120) μm is more preferable, although it varies depending on the inner layer circuit pattern, plate thickness, through hole diameter, surface via hole diameter, number of holes and insulating layer thickness setting. When the plate thickness is large and the resin filling volume of the through hole is large, a thick low viscosity layer (B) is required.
Although conductor thickness (micrometer) is not specifically limited, 2-80 are preferable, More preferably, it is 3-70, Most preferably, it is 5-50. Within this range, the printed wiring board can be made thin and the reliability of the circuit is excellent.
Therefore, the thickness (μm) of the low viscosity layer (B) is preferably 12 to 200, more preferably 13 to 190, and particularly preferably 15 to 170. Within this range, the printed wiring board can be thinned and the resin filling property between the conductors is further improved.
The thickness of the high-viscosity layer (A) after coating and drying varies depending on the thickness setting of the low-viscosity layer (B), but is preferably in the range of 5 to 50 μm. More preferably, it is 7-45, Most preferably, it is 9-40. Within this range, the adhesion between the conductor (plated copper) and the resin is further improved.
The interlayer film for a printed wiring board of the present invention comprising the layer comprising the at least two kinds of curable resin composition and the support base film thus obtained is further provided with a protective film as it is or on the low viscosity layer (B). It is preferable to laminate and store on a roll. Examples of the protective film include polyolefins such as polyethylene, polyvinyl chloride, and polypropylene, polyesters such as polyethylene terephthalate, and release paper as well as the support base film. The thickness of the protective film is preferably 5 to 100 μm. The protective film may be subjected to a release treatment in addition to the mat treatment and embossing.

The method for producing a printed wiring board of the present invention comprises a step (1) of laminating a support base film as necessary after laminating (laminating) the interlayer film for a printed wiring board of the present invention to a patterned inner layer circuit board. ), (2) the step of roughening the cured surface of the curable resin composition (JA) with an oxidizing agent after the curable resin composition (JA) and the curable resin composition (JB) are heat-cured. It is preferable to include a step (3) of forming a conductor on the roughened cured surface by a plating method.
In the step (1), as a laminating method, it is preferable to apply pressure from the support base film side and laminate at an optimum flow temperature (T). The laminated support base film is peeled off as necessary, but is preferably peeled from the viewpoint of insulation.
That is, the pressure bonding temperature is 70 to 130 ° C., the complex viscosity of the curable resin composition (JA) is 60 to 5,000 Pa · s, the complex viscosity of the curable resin composition (JB) is 50 to 1,000 Pa · s, And it is preferable to laminate on the conditions that the complex viscosity of curable resin composition (JA) is 1.2-100 times the complex viscosity of curable resin composition (JB).
If the thickness of the resin flow of the high-viscosity layer (A) during lamination is greater than the conductor thickness of the inner layer circuit and half the depth of the through hole of the inner layer circuit or greater than the depth of the surface via hole, the inner layer circuit pattern is covered and penetrated. It is preferable because the resin in the holes or the surface via holes can be filled at the same time and the surface portion of the inner circuit board can be easily covered with the high viscosity layer (A).
In addition, as a board | substrate used for an inner layer circuit board, a glass epoxy board | substrate, a metal board | substrate, a polyester board | substrate, a polyimide board | substrate, a thermosetting polyphenylene ether board | substrate etc. can be used, Even if the circuit surface is roughened beforehand. Good. Lamination is preferably performed under reduced pressure. The laminate may be a batch type or a roll type continuous type. Further, it is preferable to laminate both sides of the substrate at the same time.
When the through-hole diameter is large or the through-hole is deep (thick board thickness), it is preferable that the low viscosity layer (B) made of the curable resin composition (JB) of the interlayer film for printed wiring board is thick. Further, the surface smoothness of the resin composition layer after lamination is more excellent as the support base film is thicker, but it is disadvantageous for embedding the resin without voids between the circuit patterns. Therefore, the support base film has a conductor thickness + (0 ~ 40) More preferably, it is μm.

After the step (1) of laminating the interlayer film for printed wiring board on the inner layer circuit board, the curable resin composition (JA) and the curable resin composition (JB) are heated and cured, and then the curable resin composition ( The step (2) of roughening the cured surface of JA) with an oxidizing agent is preferably performed. After the curable resin composition (JA) and the curable resin composition (JB) are heat-cured, a predetermined through hole or surface via hole is drilled with a laser or a drill, and if necessary, the curable resin composition By roughening the hardened surface with an oxidizing agent, uneven anchors can be formed on the hardened surface.
The heat curing temperature is preferably 130 to 200 ° C. The heat curing time is preferably 10 to 120 minutes.
Roughening is performed by at least one of a dry method and a wet method. Examples of the dry roughening method for the cured resin composition layer surface include mechanical polishing such as buffing and sandblasting, plasma etching, and the like. On the other hand, wet roughening methods include chemical treatments such as permanganate, dichromate, ozone, hydrogen peroxide / sulfuric acid mixture, and oxidizing agents such as nitric acid.

After the step (2), a printed wiring board can be produced by performing the step (3) of forming a conductor on the roughened cured surface by a plating method. Examples of the plating method include a dry method and a wet plating method. These may be used together,
Examples of dry plating include vapor deposition, sputtering, and ion plating.
Examples of wet plating include electroless plating and electrolytic plating.
After roughening, if necessary, a plating resist having a pattern opposite to that of the formed conductor may be formed, and the conductor may be formed by wet plating (for example, electroless plating). After the conductor layer is formed in this way, heat treatment (annealing) (preferred conditions are 130 to 200 ° C. for 10 to 90 minutes), the curing of the thermosetting resin proceeds, and the peel strength of the conductor is further improved. Can be made.

Curable resin composition after curing measured by thermomechanical analysis (TMA) of curable resin composition (JB) contained in low-viscosity layer (B) of the interlayer film for printed wiring board in the present invention. It is preferable that the linear expansion coefficient (X) of a thing (JB) is 0-70 ppm / degrees C at 30-170 degreeC.
The coefficient of linear expansion (X) is determined by the test method IPC of The Institute for Packaging and Circuit Circuits using thermomechanical analysis (TMA) after curing a film made of a curable resin. -In accordance with the method defined in 2.4-4.41.3 of TM-650, using the measured values of the sample length at 30 ° C and 170 ° C, the linear expansion coefficient ( X) is calculated.
Linear expansion coefficient (X) = [(D) − (C)] × 10 ⁶ / [(170-30) × (C)] (ii)
However, in Formula (ii), (C) is the length of the sample at 30 ° C., and (D) is the length of the sample at 170 ° C.
This test method is published on the website of the American Printed Circuit Industry Association.

The linear expansion coefficient (X) [ppm / ° C.] is preferably 0 to 70 from the viewpoint of flatness around the opening of the through hole or surface via hole. More preferably, it is 15-65, Most preferably, it is 20-60. Within this range, the difference from the coefficient of linear expansion of the constituent material of other printed wiring boards does not become too large, and the thermal shock resistance is good, and the smoothness around the opening of the through hole or surface via hole is further impaired. It becomes difficult to be.
If the smoothness around the opening of the through hole or surface via hole is not impaired, the yield is improved when an interlayer insulating layer and a conductor circuit are further formed in the region including the periphery of the opening of the through hole or surface via hole. It tends to be easy.

  Examples of the method for reducing the linear expansion coefficient include a method for increasing the inorganic filler content, a method for increasing the glass transition temperature of the curable resin, and the like.

<Measuring method of linear expansion coefficient (X)>
As the measurement sample, a film of a curable resin composition (JB) (a film is separately prepared for measurement) heated and cured at 170 ° C. for 90 minutes is used. The size of the sample was (length) 15 mm x (width) 2 mm x (thickness) 0.040 mm at 25 ° C, and the length and width of the cured film were measured with calipers. The thickness was measured with a film thickness meter. The measurement device uses TMA (for example, TMA / SS6100 manufactured by Seiko Instruments Inc.), and the measurement sample is pulled with a load of 30 mN, and the measurement cell containing the sample is held at 30 ° C. for 30 minutes, and then the measurement cell temperature The temperature is raised from 30 ° C. to 230 ° C. at a rate of 10 ° C./min. The values of (C) and (D) are put into the above equation (ii) to calculate the linear expansion coefficient (X).

When the interlayer film for a printed wiring board of the present invention is used, the surface smoothness is excellent. Therefore, the above-described production method is repeated a plurality of times, and a multilayer printed wiring board can be produced by laminating build-up layers in multiple stages.
In addition, since the smoothness around the through hole opening is extremely high, even if the interlayer insulating layer is formed at the same time as filling the through hole, the yield of the conductor circuit formation in the next process is extremely low, and the through hole filling agent is used in the build-up board manufacturing process. It is suitable as a combined interlayer insulating material.
As described above, using the interlayer film for printed wiring board of the present invention, through hole filling and interlayer insulating layer are simultaneously formed and laminated in multiple stages by a build-up method, and the multilayer printed wiring board is a personal computer, a camera-integrated VTR, Used in electrical products such as digital video cameras, mobile phones, car navigation systems, and digital cameras.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise noted, “part” means “part by weight” and “%” means “% by weight”.

The evaluation method was performed by the following method.
<Complex viscosity>
According to the method described above. Measuring apparatus: ARES, manufactured by Rheometric Scientific <Linear expansion coefficient after curing>
According to the method described above. Measuring device: TMA / SS6100, manufactured by Seiko Instruments Inc. <embeddability of through hole>
The resin shape of the cross section passing through the center of the through hole was visually observed and evaluated according to the following criteria.
○: The inside of the through hole is filled with resin ×: A part of the through hole is not filled with resin

<Smoothness around the through-hole opening>
Using a shape measuring microscope (Keyence Co., Ltd., ultra-deep shape measuring microscope VK-8550), the center position of the cured resin composition surface of the through-hole opening and 150 μm outside from the outer diameter of the through-hole opening. The height difference of the surface of the cured resin composition to be measured was measured for 10 through holes, and the average value of these height differences (dent amount) was used as an index of smoothness. The smaller the value, the better the smoothness and dimensional stability.

<Peel strength>
After roughening, a palladium catalyst (manufactured by ATOTEC, trade name: Neo gasth 834) was dipped on the substrate, activated, and then immersed in an electroless plating solution (copper sulfate 12 g / L, formaldehyde 7.5 g / L). The electroless plating layer having a thickness of 2 μm was formed by immersing at 20 ° C. for 20 minutes. Thereafter, electrolytic plating with a thickness of 32 μm was further performed in a copper sulfate electrolytic plating bath. About the board | substrate produced in this way, the adhesiveness of a board | substrate and a copper plating layer was measured with the measuring method of the peeling strength described in JISC6481.

<Production Example 1>
After charging 5 parts of MEK (methyl ethyl ketone) in a reaction vessel substituted with nitrogen and raising the temperature to 80 ° C., 20 parts of GMA (glycidyl methacrylate) and St (styrene) uniformly dissolved in another nitrogen-substituted vessel ) A mixture of 20 parts, 2-EHA (2-ethylhexyl acrylate) 5 parts, MEK 20 parts and azobisisobutyronitrile 1.5 parts was dropped into the reaction vessel over 4 hours.
After completion of the dropping, the mixture was aged at 100 ° C. for 5 hours to obtain a GMA / St / 2-EHA copolymer as a polymer epoxy resin. The copolymer (polymer epoxy resin) had an Mw (polystyrene equivalent weight average molecular weight measured by GPC) of 30,000 and a glass transition temperature of 58 ° C. The epoxy equivalent (measured according to JIS K7236) of this copolymer (polymer epoxy resin) was 320.

<Production Example 2>
38 parts of “Epomic R-140S” (bisphenol A type epoxy resin: manufactured by Mitsui Chemicals, Inc.) and “SA-102” (1,8-diazabicyclo [5,4,0] are placed in a reaction vessel substituted with nitrogen. -7-Undecene octylate (manufactured by San Apro Co., Ltd.) was charged with 1 part, heated to 110 ° C., and then “HCA” (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide : Sanko Co., Ltd.) 22 parts were charged into the reaction vessel in 10 portions over 3 hours.
After completion of the divided charging, the mixture was aged at 120 ° C. for 3 hours to obtain a phosphorus-containing flame retardant. The epoxy equivalent of the phosphorus-containing flame retardant was 660.

<Example 1>
<Solution of curable resin composition (α1)>
7.5 parts of the polymer epoxy resin obtained in Production Example 1 in a planetary mixer, “JSR TR-2250” (styrene-butadiene copolymer: manufactured by JSR Corporation), 5.4 parts, “Epicoat 154” (Phenol novolac epoxy resin: Japan Epoxy Resin Co., Ltd., epoxy equivalent 172) 18 parts, “EOCN-104” (Cresol novolac epoxy resin: Nippon Kayaku Co., Ltd., epoxy equivalent 210) 12 parts, “PSM-4326” (Phenol-based curing agent: phenol novolak resin: manufactured by Gunei Chemical Industry Co., Ltd.) 18 parts, phosphorus-containing flame retardant 9 parts obtained in Production Example 2, “SA-102” 0.1 part and “Admafine SO-” C3 "(silica: manufactured by Admatechs Co., Ltd.) 30 parts are added to 35 parts of MEK and 25 to 35 ° C. And mixed for 1 hour to obtain a solution of a curable resin composition for forming a high viscosity layer ([alpha] 1).
This solution was applied to a 50 μm thick PET film with a roll coater so that the resin thickness after drying was 40 μm, and then dried at 90 ° C. for 4 minutes to form a high-viscosity layer. The complex viscosity was measured.
The complex viscosity of the curable resin composition (α1) was 70 ° C .: 2,000 Pa · s, 90 ° C .: 250 Pa · s, 110 ° C .: 60 Pa · s, and 130 ° C .: 50 Pa · s.
The relationship between the temperature and viscosity of the curable resin composition is summarized in Table 1.
Table 2 summarizes the contents of the inorganic filler (silica) and the roughening component (the polymer epoxy resin obtained in Production Example 1) in the curable resin composition.

<Solution of curable resin composition (β1)>
3 parts of resin obtained in Production Example 1 in a planetary mixer, 2 parts of “JSR TR-2250”, 25 parts of “Epicoat-154”, 15 parts of “PSM-4326”, difficulty in containing phosphorus obtained in Production Example 2 4.7 parts of flame retardant, 0.3 part of “SA-102” and 50 parts of “Admafine SO-C3” are added to 25 parts of MEK, and the viscosity is low as in the case of the curable resin composition (α1). A solution of a curable resin composition (β1) for forming a layer was obtained.
The complex viscosity of this solution was measured in the same manner as in the case of the curable resin composition (α1).
The complex viscosity of the curable resin composition (β1) was 70 ° C .: 900 Pa · s, 90 ° C .: 90 Pa · s, 110 ° C .: 55 Pa · s, and 130 ° C .: 40 Pa · s.

<Film formation of lower layer curable resin composition (α1) and upper layer curable resin composition (β1)>
A curable resin composition (α1) solution is applied to a PET film having a thickness of 50 μm by a roll coater so that the resin thickness after drying is 20 μm, and then dried at 90 ° C. for 4 minutes to be curable. A high viscosity layer of the resin composition (α1) was formed. Next, a solution of the curable resin composition (β1) is coated on the high viscosity layer by a roll coater so that the resin thickness after drying is 40 μm, and then cured by drying at 90 ° C. for 7 minutes. The low-viscosity layer made of the curable resin composition (β1) was formed to obtain an interlayer film for a printed wiring board of lower layer curable resin composition (α1) / upper layer curable resin composition (β1) (residual solvent amount 2 .1%).

<Example 2>
<Solution of curable resin composition (α2)>
8 parts of the resin obtained in Production Example 1 in a planetary mixer, 6 parts of “JSR TR-2250”, 7.8 parts of “Epicoat-154”, 20 parts of “EOCN-104”, 17 parts of “PSM-4326”, 6 parts of phosphorus-containing flame retardant obtained in Production Example 2, 0.2 part of “SA-102” and 35 parts of “Admafine SO-C3” were added to 30 parts of MEK in the same manner as in Example 1. A solution of a curable resin composition (α2) that forms a high viscosity layer was obtained.
When measured in the same manner as in Example 1, the complex viscosity of the curable resin composition (α2) was 70 ° C .: 9,000 Pa · s, 90 ° C .: 1,500 Pa · s, 110 ° C .: 800 Pa · s, 130 ° C .: 500 Pa · s.

<Solution of curable resin composition (β2)>
5 parts of resin obtained in Production Example 1 in a planetary mixer, 3 parts of “JSR TR-2250”, 11 parts of “Epicoat-154”, 5.8 parts of “EOCN-104”, 12 parts of “PSM-4326”, 3 parts of phosphorus-containing flame retardant obtained in Production Example 2, 0.2 part of “SA-102” and 60 parts of “Admafine SO-C3” are added to 30 parts of MEK and mixed in the same manner as in Example 1. A solution of a curable resin composition (β2) that forms a low viscosity layer was obtained.
When measured in the same manner as in Example 1, the complex viscosity of the curable resin composition (β2) was 70 ° C .: 1,300 Pa · s, 90 ° C .: 400 Pa · s, 110 ° C .: 150 Pa · s, 130 ° C .: 100 Pa.・ It was s.

<Film formation of lower layer curable resin composition (α2) and upper layer curable resin composition (β2)>
Using the solution of the curable resin composition (α2) and the solution of the curable resin composition (β2) in the same manner as in Example 1, the lower curable resin composition (α2) / upper curable resin composition (β2 ) Was obtained (residual solvent amount 2.3%).

<Example 3>
<Film formation of lower layer curable resin composition (α2) and upper layer curable resin composition (β1)>
Using the solution of the curable resin composition (α2) and the solution of the curable resin composition (β1) in the same manner as in Example 1, the lower curable resin composition (α2) / upper curable resin composition (β1 ) Was obtained (residual solvent amount 2.2%).

<Example 4>
<Solution of curable resin composition (α3)>
In the production of the solution of the curable resin composition (α1) of Example 1, the solution of the curable resin composition (α3) was similarly obtained except that 9 parts of the phosphorus-containing flame retardant obtained in Production Example 2 was not used. Got.
When measured in the same manner as in Example 1, the complex viscosity of the curable resin composition (α3) was 70 ° C .: 3,500 Pa · s, 90 ° C .: 510 Pa · s, 110 ° C .: 150 Pa · s, 130 ° C .: 100 Pa.・ It was s.

<Film formation of lower layer curable resin composition (α3) and upper layer curable resin composition (β2)>
Using the solution of the curable resin composition (α3) and the solution of the curable resin composition (β2) in the same manner as in Example 1, the lower curable resin composition (α3) / upper curable resin composition (β2 ) Was obtained (residual solvent amount 2.2%).

<Example 5>
<Solution of curable resin composition (β3)>
"Epicoat E1256" (bisphenol A type phenoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., Mw 50,000) 7 parts, "Epicoat-154" 27 parts, "PSM-4326" 17 parts, "SA-102" 0.3 parts and 50 parts of “Admafine SO-C3” were added to 25 parts of MEK and mixed in the same manner as in Example 1 to obtain a solution of a curable resin composition (β3) that forms a low viscosity layer. .
When measured in the same manner as in Example 1, the complex viscosity of the curable resin composition (β3) was 70 ° C .: 800 Pa · s, 90 ° C .: 50 Pa · s, 110 ° C .: 30 Pa · s, 130 ° C .: 20 Pa · s. Met.

<Film formation of lower layer curable resin composition (α3) and upper layer curable resin composition (β3)>
Using the solution of the curable resin composition (α3) and the solution of the curable resin composition (β3) in the same manner as in Example 1, the lower curable resin composition (α3) / upper curable resin composition (β3 ) Was obtained (residual solvent amount 2.3%).

<Example 6>
<Film formation of lower layer curable resin composition (α2), intermediate layer curable resin composition (α1), upper layer curable resin composition (β3)>
A curable resin composition (α2) solution is applied to a PET film having a thickness of 50 μm with a roll coater so that the resin thickness after drying is 10 μm, and then dried at 90 ° C. for 3 minutes to be curable. A curable resin composition of the resin composition (α1) was formed. Next, a solution of the curable resin composition (α1) is applied onto the dried resin on a 50 μm thick PET film by a roll coater so that the resin thickness after drying is 10 μm. A curable resin composition of the curable resin composition (α1) was formed by drying for a minute. Next, a curable resin composition (β3) solution is applied on the entire surface of the dried resin with a roll coater so that the resin thickness after drying is 40 μm, and then dried at 90 ° C. for 7 minutes. A curable resin composition of a resin composition (β3) is formed, and a printed wiring board of lower layer curable resin composition (α2) / intermediate layer curable resin composition (α1) / upper layer curable resin composition (β1) An interlayer film was obtained (residual solvent amount 2.3%).

<Example 7>
<Film formation of lower layer curable resin composition (α3) and upper layer curable resin composition (β1)>
Using the solution of the curable resin composition (α3) and the solution of the curable resin composition (β1) in the same manner as in Example 1, the lower curable resin composition (α3) / upper curable resin composition (β1 ) Was obtained (residual solvent amount 2.2%).

<Comparative Example 1>
<Film formation of lower layer curable resin composition (α1) and upper layer curable resin composition (β2)>
Using the solution of the curable resin composition (α1) and the solution of the curable resin composition (β2) in the same manner as in Example 1, the lower curable resin composition (α1) / upper curable resin composition (β2 ) Was obtained (residual solvent amount 2.1%).

<Comparative example 2>
<Film formation of lower layer curable resin composition (α2) and upper layer curable resin composition (α1)>
Using the solution of the curable resin composition (α2) and the solution of the curable resin composition (α1) in the same manner as in Example 1, the lower curable resin composition (α2) / upper curable resin composition (α1 ) Was obtained (residual solvent amount 2.3%).

<Comparative Example 3>
<Film formation of lower layer curable resin composition (β2) and upper layer curable resin composition (β1)>
Using the solution of the curable resin composition (β2) and the solution of the curable resin composition (α1) in the same manner as in Example 1, the lower curable resin composition (β2) / upper curable resin composition (β1 ) Was obtained (residual solvent amount 2.1%).

<Comparative example 4>
The whole solution of the curable resin composition (α1) of Example 1 was applied to a PET film having a thickness of 50 μm with a roll coater so that the resin thickness after drying was 60 μm, and then dried at 90 ° C. for 7 minutes. Thus, a curable resin composition of the curable resin composition (α1) was formed. (Residual solvent amount 2.3%)
<Comparative Example 5>
The whole solution of the curable resin composition (β1) of Example 1 was applied to a 50 μm thick PET film with a roll coater so that the resin thickness after drying was 60 μm, and then dried at 90 ° C. for 7 minutes. Thus, a curable resin composition of the curable resin composition (β1) was formed. (Residual solvent amount 2.2%)

<Test Example 1>
On the glass epoxy inner layer circuit board having the inner layer circuit and the through hole, the interlayer film for a printed wiring board obtained in Example 1 is double-sided at a temperature of 90 ° C., a pressure of 0.1 MPa, and a pressure of 0.2 kPa with a pressure of 60 seconds using a vacuum laminator. Laminated at the same time. After cooling to 25 ° C., the PET film was peeled off and cured at 170 ° C. for 20 minutes, and a predetermined φ0.07 surface via hole was drilled with a carbon dioxide laser. Next, the surface of the resin composition was roughened with an alkaline oxidant of permanganate, and a conductor layer was formed on the entire surface by electroless plating and electrolytic plating. Then, a four-layer printed wiring board was obtained according to the subtractive method. Thereafter, in order to stabilize the adhesion strength of the conductor, annealing was performed at 170 ° C. for 60 minutes to obtain a substrate (Z1).
With respect to this substrate (Z1), the through hole embedding property, the smoothness around the through hole opening, the penetration of the resin into the through hole, and the peel strength were evaluated, and the results are shown in Table 3. Similarly, the result about Test Examples 2-8 and Comparative Test Examples 1-7 is shown in Tables 3-6.

<Test Examples 2 to 6>
Test Example 1 except that the interlayer film for printed wiring board obtained in Examples 2 to 6 was used in place of the “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above. In the same manner, substrates (Z2) to (Z6) were obtained.

<Test Example 7>
Instead of “interlayer film for printed wiring board obtained in Example 1” in Test Example 1, the interlayer film for printed wiring board obtained in Example 7 was used, and “temperature 90 ° C., pressure 0. A substrate (Z7) was obtained in the same manner as in Test Example 1 except that the test was performed at “temperature 110 ° C., pressure 0.08 MPa” instead of “1 MPa”.

<Test Example 8>
Instead of “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above, the interlayer film for printed wiring board obtained in Example 5 was used, and “temperature 90 ° C., pressure 0. A substrate (Z8) was obtained in the same manner as in Test Example 1, except that the test was performed at “temperature 70 ° C., pressure 0.4 MPa” instead of “1 MPa”.

<Comparative Test Example 1>
In the same manner as in Test Example 1 except that the interlayer film for printed wiring board obtained in Comparative Example 1 was used in place of the “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above. A substrate (H1) was obtained.

<Comparative Test Example 2>
A substrate (H2) was obtained in the same manner as in Test Example 1, except that the test was performed at “Temperature 110 ° C., Pressure 0.08 MPa” instead of “Temperature 90 ° C., Pressure 0.1 MPa” in Test Example 1. .

<Comparative Test Example 3>
A substrate (H3) was obtained in the same manner as in Test Example 1, except that the test was performed at “Temperature 70 ° C., Pressure 0.4 MPa” instead of “Temperature 90 ° C., Pressure 0.1 MPa” in Comparative Test Example 1 above. It was.

<Comparative Test Example 4>
Instead of “interlayer film for printed wiring board obtained in Example 1” in Test Example 1, the interlayer film for printed wiring board obtained in Comparative Example 2 was used, and “temperature 90 ° C., pressure 0.1 MPa” was used. The substrate (H4) was obtained in the same manner as in Test Example 1 except that the test was performed at “temperature 110 ° C., pressure 0.05 MPa”.

<Comparative Test Example 5>
In the same manner as in Test Example 1 except that the interlayer film for printed wiring board obtained in Comparative Example 3 was used in place of the “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above. A substrate (H5) was obtained.

<Comparative Test Example 6>
In the same manner as in Test Example 1 except that the interlayer film for printed wiring board obtained in Comparative Example 4 was used in place of the “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above. A substrate (H6) was obtained.

<Comparative Test Example 7>
In the same manner as in Test Example 1 except that the interlayer film for printed wiring board obtained in Comparative Example 5 was used in place of the “interlayer film for printed wiring board obtained in Example 1” in Test Example 1 above. A substrate (H7) was obtained.

（注）ふくれ・・・スルーホール開口部周辺の樹脂組成物表面が上方向に１０μm以上膨らんだ

(Note) Swelling ... The surface of the resin composition around the opening of the through hole swelled upward by 10 μm or more.

From the results of Examples and Test Examples, it can be seen that when the interlayer film for a printed wiring board of the present invention is used, coating of the inner layer circuit pattern and filling of the resin in the through hole or surface via hole can be performed simultaneously.
Furthermore, when the method for producing a printed wiring board of the present invention is used, the surface smoothness around the through-hole opening is excellent, so that the dimensional stability is good, and the adhesion between the resin and the conductor can be ensured. Using this, a printed wiring board can be manufactured with high productivity.
From the results of Comparative Test Examples 1 and 2, when the complex viscosity of the curable resin composition (JA) during lamination is less than 1.2 times that of the curable resin composition (JB), the curable resin is contained in the through hole. The composition (JA) entered and the smoothness of the through-hole opening was not good.
From the results of Comparative Test Example 3, when the complex viscosity at the time of laminating the curable resin composition (JB) is greater than 10,000 Pa · s, the through hole embedding property is poor, and the resin is embedded in the through hole without voids. Have difficulty.
From the result of Comparative Test Example 4, when the inorganic filler content of the curable resin composition (JB) was less than 35% by weight, the smoothness of the through-hole opening was not good. Moreover, when the inorganic filler content of the curable resin composition (JA) was greater than 45% by weight from the results of Comparative Test Example 5, the peel strength was small, and the adhesion between copper and the resin was insufficient.
From the result of Comparative Test Example 6, when the interlayer film for a printed wiring board was composed of a single high-viscosity layer, the resin filling into the through hole was insufficient.
From the result of Comparative Test Example 7, when the interlayer film for a printed wiring board was composed of a single low-viscosity layer, the peel strength was small and the adhesion between copper and resin was insufficient.

  The method for producing an interlayer film for a printed wiring board and a printed wiring board according to the present invention is suitable as an interlayer insulating material that also serves as a hole filling agent, and uses the interlayer film for a printed wiring board according to the present invention, and is a multi-layer laminated by a build-up method. Printed wiring boards are used in electrical products such as personal computers, camera-integrated VTRs, digital video cameras, mobile phones, car navigation systems, and digital cameras.

Claims (8)

On the support base film, it has a high viscosity layer (A) made of a curable resin composition (JA), and a low viscosity layer (B) made of a curable resin composition (JB),
The interlayer film for printed wiring boards in which the curable resin composition (JA) and the curable resin composition (JB) satisfy the conditions (1) and (2).
(1) The complex viscosity of the curable resin composition (JA) is 60 to 5,000 Pa · s, the complex viscosity of the curable resin composition (JB) is 50 to 1,000 Pa · s, and the curable resin composition. The optimum flow temperature (T) at which the complex viscosity of the product (JA) is 1.2 to 100 times the complex viscosity of the curable resin composition (JB) is 70 to 130 ° C.
(2) The curable resin composition (JA) and the curable resin composition (JB) contain an inorganic filler, and the content of the inorganic filler in the curable resin composition (JA) is the curable resin composition (JA). The content of the inorganic filler of the curable resin composition (JB) is 35 to 75% by weight based on the weight of the curable resin composition (JB). The interlayer film for printed wiring boards according to claim 1, wherein the high viscosity layer (A) is sandwiched between the support base film and the low viscosity layer (B). The interlayer film for printed wiring boards according to claim 1 or 2, wherein the curable resin composition (JA) and the curable resin composition (JB) contain an epoxy resin having two or more epoxy groups in the molecule. The interlayer film for printed wiring boards according to any one of claims 1 to 3, wherein the curable resin composition (JB) has a linear expansion coefficient after curing of 0 to 70 ppm / ° C. The interlayer film for printed wiring boards according to any one of 1 to 4, wherein the high viscosity layer (A) has a thickness of 5 to 50 µm, and the low viscosity layer (B) has a thickness of 12 to 200 µm. The curable resin composition (JA) contains at least one oxidizing agent-soluble roughening component selected from the group consisting of rubber, amino resin, inorganic filler, and organic filler. Interlayer film for printed wiring boards. A process (1) of laminating the support base film as necessary after laminating the interlayer film for printed wiring boards according to any one of claims 1 to 6 on the patterned inner layer circuit board at an optimum flow temperature (T). ), (2) the step of roughening the cured surface of the curable resin composition (JA) with an oxidizing agent after the curable resin composition (JA) and the curable resin composition (JB) are heat-cured. A method for producing a printed wiring board, comprising a step (3) of forming a conductor on the roughened cured surface by a plating method. A printed wiring board comprising a cured body of the interlayer film for a printed wiring board according to claim 1.