JP2003234439A - Insulative resin composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To give good laser processing characteristics to an insulative resin composite for sealing available to a wiring board incorporating an electronic component. <P>SOLUTION: In an insulative resin composite composed of a nonconductive filler dispersed in a thermosetting material, an average particle size of the nonconductive filter sued is 0.3-20 μm and the ratio of the insulative filler of 64 μm or over in size included in the total nonconductive filler is 5.0 weight percent or below. The insulative resin composite preferably does not include silicone oil so as to improve its platability. The wiring board incorporating an electric component which uses the insulative resin composite comprises a first wring substrate 3 which includes a first wiring 2 formed on at least one side of a first substrate 1, an electric part 4 connected to the first wiring 2 of the first wiring substrate 3, an insulation layer 5 for sealing the electric component 4, a second wring substrate 8 which includes a second wiring 7 formed on at least one side of a second substrate 6 provided on the insulation layer 5, and via hole 9 for connecting the first wiring 2 and second wiring 7. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an insulating resin composition suitable for sealing electronic parts. In particular, the present invention relates to an insulating resin composition used for incorporating an electronic component such as a semiconductor chip inside an insulating layer of a wiring board for mounting various electronic components on the surface.

[0002]

2. Description of the Related Art Conventionally, in order to improve the mounting density of a wiring board for mounting various electronic components such as semiconductor chips, regarding wiring, the wiring rule in the surface direction of the wiring board is made finer, Wiring is stacked in the thickness direction. Regarding semiconductor chips, a bare chip is directly connected to a wiring board in a leadless manner by a flip chip method.

However, the mounting space on the surface of the wiring board is limited, and it is difficult to mount a large number of electronic components such as semiconductor chips on the surface of the wiring board at high density.

Therefore, recently, it has been attempted to incorporate an electronic component such as a semiconductor chip mounted on the surface of the wiring board in the insulating layer of the wiring board (Japanese Patent Laid-Open No. 2001-77).
No. 536). A schematic sectional view of an example of such a wiring board with built-in electronic components is shown in FIG. This wiring board with a built-in electronic component includes an electronic component 34 connected to a lower copper wiring 32 of a glass epoxy substrate 31 with an adhesive 33, and an insulating layer 3 covering a solder resist layer 35 so as to seal the electronic component 34.
6, an upper layer copper wiring 38 formed thereon via an epoxy resin layer 37, a lower layer copper wiring 32, and an upper layer copper wiring 38.
Via hole 39 for connecting to (hole 40 for via hole
Inner wall of which the copper plating layer 41 is formed).

By the way, in the conventional insulating resin composition for encapsulation used for producing a wiring board with a built-in electronic component, the epoxy resin which is the insulating resin used has a relatively large curing shrinkage and thermal expansion. A non-conductive filler such as silica fine particles is added in an amount of 60 to 90% by weight in order to reduce the rate.

[0006]

However, the conventional insulating resin composition for sealing used in the wiring board with a built-in electronic component shown in FIG. 3 is for simply sealing the semiconductor chip on the wiring board. Therefore, the laser processability when forming the via hole hole (the property that a hole having the intended shape and size can be formed by laser processing) is not taken into consideration, and the plating property of the inner surface of the via hole hole ( The property that electroless plating metal can be deposited is not considered. For this reason, as shown in FIG. 4, a recess 42 is formed on the inner surface of the via hole hole 40 during laser processing, and as a result, there is a concern that the plating adhesion of the inner surface of the via hole hole may deteriorate.

The present invention is intended to solve the above-mentioned problems of the prior art, and provides a good laser processability to an insulating resin composition for sealing which can be used for a wiring board with a built-in electronic component. The purpose is to give.

[0008]

SUMMARY OF THE INVENTION The present inventors have found that the problem of the laser processability of conventional encapsulating insulating resin compositions is that the average particle size of the non-conductive filler added is relatively large. The present invention was completed based on the finding that it largely depends on the content ratio of the diameter of the filler.

That is, the present invention provides an insulating resin composition comprising a non-conductive filler dispersed in a thermosetting component,
The non-conductive filler has an average particle size of 0.3 to 20 μm, and the ratio of the non-conductive filler having a particle size of 64 μm or more in all the non-conductive filler is 5.0% by weight or less. A resin composition is provided.

Further, according to the present invention, there is provided a first wiring board having a first wiring formed on at least one surface of a first base material, and an electronic component connected to the first wiring on the first wiring board. An insulating layer for encapsulating the electronic component, a second wiring substrate provided on the insulating layer and having second wiring formed on at least one surface of a second base material, first wiring, and second wiring In a wiring board with a built-in electronic component, which comprises a via hole connecting to and, the insulating layer is formed from an insulating resin composition in which a non-conductive filler is dispersed in a thermosetting component. And the average particle size of the non-conductive filler is 0.3 to 20 μm.
The present invention provides a wiring board with a built-in electronic component, characterized in that the proportion of non-conductive fillers having a particle size of 64 μm or more in all non-conductive fillers is 5.0% by weight or less.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The insulating resin composition of the present invention has a non-conductive filler dispersed in a thermosetting component. Here, the non-conductive filler has an average particle size of 0.3.
˜20 μm, preferably 3 to 15 μm,
A non-conductive filler having a particle size of 64 μm or more in the total non-conductive filler is 5.0% by weight or less, preferably 3.5% by weight or less. Those having an average particle size of less than 0.3 μm are difficult to obtain, and those having an average particle size of more than 20 μm are not preferable because they cause the laser-machined surface to be engraved and the laser-machinability is deteriorated too much. Further, it is preferable that the ratio of the non-conductive filler having a particle size of 64 μm or more in all the non-conductive fillers exceeds 5.0% by weight because the laser processability is excessively lowered even if the average particle size is 20 μm or less. Absent.

The ratio of the non-conductive filler having a particle size of 64 μm or more is determined by a laser scattering particle size measuring device (for example, CIL).
AS MODEL 715, CILAS MODEL
920 (both are manufactured by CILAS).

As such a non-conductive filler, a known non-conductive filler in which the average particle size and the proportion of the non-conductive filler having a particle size of 64 μm or more in all the non-conductive fillers satisfy the above-mentioned ranges. Can be used. Among them, silica fine particles can be preferably used in terms of hygroscopicity, thermal expansion coefficient, and insulating property.

If the content of the non-conductive filler in the insulating resin composition is too small, the curing shrinkage and the thermal expansion coefficient cannot be effectively controlled, and if it is too large, the viscosity of the composition becomes too high. %, Preferably 60 to 90% by weight, more preferably 70 to 85% by weight.

The thermosetting component used in the present invention includes
The thermosetting component used in the conventional insulating resin composition for sealing can be used. Above all, a thermosetting component containing a polymerizable epoxy compound, a curing agent and, if necessary, a curing aid can be preferably used from the viewpoint of a balance between economic efficiency and performance.

As such a polymerizable epoxy compound, an epoxy monomer or oligomer having a molecular weight (weight average molecular weight) of 10,000 or less can be preferably mentioned. For example, glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenol novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, polypropylene glycol; phthalic acid, isophthalic acid, tetrahydrophthalic acid, etc. Examples thereof include epoxy monomers such as glycidyl ester of carboxylic acid, oligomers thereof, and alicyclic epoxides. Among them, bisphenol A glycidyl ether monomer or oligomer can be preferably used. Specifically, Epicoat 828 (molecular weight 380), Epicoat 834 (molecular weight 470), Epicoat 1001 (molecular weight 900), Epicoat 1002 (molecular weight 1060), Epicoat 10 manufactured by Yuka Shell Co., Ltd.
55 (molecular weight 1350), Epicoat 1007 (molecular weight 2900) and the like can be used. These may be used alone or in combination of two or more.

As the curing agent, known ones can be used, for example, acid anhydride type curing agents (eg phthalic anhydride, maleic anhydride etc.), amine type curing agents (eg ethylenediamine, menthene). Diamine, diaminodiphenylmethane, etc.), polyamide-based curing agents, phenol-based curing agents (eg, phenol novolac, etc.), polymercaptan-based curing agents, etc. can be used.

The amount of the curing agent used is 50 to 50 relative to the stoichiometric amount calculated from the epoxy equivalent of the polymerizable epoxy compound.
It is 150%.

As the curing aid (accelerator), an amine-based curing aid (eg, triethylenediamine, benzyldimethylamine, etc.), an imidazole-based curing aid (eg, 2-methylimidazole, 2-phenylimidazole, etc.) ), Phosphine-based curing aids (eg, triphenylphosphine, tributylphosphine, etc.), phosphonium salt-based curing aids, metal chelate-based curing aids, and the like.

The amount of the curing aid used is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the polymerizable epoxy compound.

In the insulating resin composition of the present invention, in addition to the above-mentioned components, a cross-linking agent, various rubber components, a coupling agent, a leveling agent, a viscosity modifier, an antioxidant, etc. are appropriately blended. can do. However, it is preferable not to use silicone oil widely used as a plasticizer in the insulating resin composition of the present invention. When silicone oil is blended, the problem that the plating metal does not deposit on the inner surface of the via hole hole, the problem that the adhesion is insufficient even if it deposits, and the insulation formed from the insulating resin composition This is not preferable because it causes a problem of insufficient adhesion between the layer and the layer adjacent thereto.

The insulative resin composition of the present invention can be prepared by uniformly mixing the thermosetting component, the non-conductive filler, and various additives which are added as necessary, by a conventional method. . This insulating resin composition is used in the form of a liquid or a paste, although it varies depending on the type and amount ratio of the raw materials used.

The insulating resin composition of the present invention can be used in the same manner as the conventional resin composition for sealing a semiconductor chip, but since it exhibits good laser processability, it can be used as an electronic component of a wiring board with a built-in electronic component. It can be used as a sealing layer and an insulating layer for components.

The basic structure of a wiring board with a built-in electronic component obtained by using the insulating resin composition of the present invention is, as shown in FIG. 1, at least the first substrate 1 (glass epoxy substrate or the like). A first wiring board 3 (a single-sided copper-clad glass epoxy board or the like) having a first wiring 2 (copper wiring or the like) formed on one surface thereof, and an electronic component connected to the first wiring 2 on the first wiring board 3. 4 (semiconductor chip, capacitor, resistor, etc.), insulating layer 5 for sealing electronic component 4, and second substrate 6 (epoxy resin layer, etc.) provided on insulating layer 5 on at least one surface A second wiring board 8 (a single-sided copper-clad flexible board or the like) on which a second wiring 7 (copper wiring or the like) is formed, and a first wiring 2
And a via hole 9 connecting the second wiring 7 to the second wiring 7. Here, the insulating layer 5 is preferably formed from the insulating resin composition of the present invention containing no silicone oil. A solder resist layer 10 may be formed between the first wiring board 3 and the insulating layer 5. The first wiring 2 and the electronic component 4 are
It may be connected via the anisotropic conductive adhesive film 11.

The electronic component built-in wiring board of FIG. 1 can be manufactured as shown in FIG.

First, the area of the first wiring 2 to which the electronic component 4 is to be connected is exposed by screen printing on the first wiring board 3 having the first wiring 2 formed on one surface of the first base material 1. As described above, the solder resist layer 10 is provided (FIG. 2A).

Next, the electronic component 4 is flip-chip connected to the first wiring 2 via, for example, the anisotropic conductive adhesive film 11 (FIG. 2B).

Next, the sealing insulating resin composition is applied to the entire surface of the solder resist layer 10 so as to seal the electronic component 4, and a coating film of the sealing insulating resin composition is applied to Two
A wiring metal layer 7 ′ such as a copper foil formed on one surface of the wiring board 8 is laminated from the side of the second base material 6 and the whole is heated and pressed to cure the coating film to form the insulating layer 5. Together with the whole (FIG. 2 (c)).

Further, a via hole window is formed in the wiring metal layer 7 ′ by etching, and a laser beam is irradiated therethrough until the first wiring 2 is exposed to make a hole, thereby forming a via hole hole 12. (FIG. 2 (d)). Then, it is preferable to perform desmear processing as needed.

Next, electroless plating is performed, and then electrolytic plating is performed to form a connection metal layer 13 such as copper plating on the inner surface of the via hole 12 to form the first wiring 2 and the wiring metal layer. 7'and the via hole 9 electrically connected to it is formed, and the second wiring 7 is formed by patterning the wiring metal layer 7'according to a conventional method to obtain the electronic component built-in wiring board (FIG. 2 (e )).

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples.

Examples 1 to 6 and Comparative Examples 1 to 6 Each component of the compounding table shown in Table 1 and Table 2 was stirred by a planetary mixer (Inoue Seisakusho), and further, a three-roll type kneader ( By kneading with Noritake Co., Ltd., an insulating resin composition having the viscosities shown in Tables 1 and 2 (viscosity in the region of shear rate γ = 100 S ⁻¹ by a rheometer) was prepared.

A wiring board with a built-in semiconductor chip was prepared as shown in FIG. 2 using the obtained insulating resin composition.

First, a solder resist layer (CCR-510, Asahi Kaken Co., Ltd.) having a thickness of 20 μm is provided on a lower copper wiring having a thickness of 400 μm formed on one surface of a glass epoxy substrate, and then a semiconductor chip is connected. The semiconductor chip (size: 6.3 mm square, 0.4 mm) with an anisotropic conductive adhesive film (FP4011K, Sony Chemical Co.) removed from the solder resist layer in the copper wiring region
Thickness) was flip-chip bonded.

Next, the insulating resin compositions of Examples and Comparative Examples were applied to the entire surface of the solder resist layer with a squeegee so as to have a thickness of 180 μm so as to seal the semiconductor chip, and the whole was heated and pressed. (1 hour at 100 ° C, then 150
The coating film was cured by heating at 0 ° C. for 1 hour to form an insulating layer. A 12 μm thick copper foil (RCC) with an 80 μm thick epoxy resin layer formed on one surface on the insulating layer.
(Resin coated copper); APL-4001 2X,
Sumitomo Bakelite Co., Ltd.) was laminated from the epoxy resin layer side, and heated and pressed (180 ° C., 392 N / cm ² ) to cure.

Next, a via hole window is formed by etching on the copper foil on the RCC surface, and a carbon dioxide gas laser beam (LC-1C21 / 1C, Hitachi Via Mechanics Co., Ltd.) is used to form a lower layer on the glass epoxy substrate. Irradiation was performed until the copper wiring was exposed to form a via hole having a diameter of 300 μm.

Next, after forming a plating resist layer on the copper foil on the RCC surface, electroless copper plating (plating bath: PB-555, Ebara-Eugelite Co., Ltd.) and electrolytic copper plating (plating bath: plating bath: EX2, Ebara Eugelite Co., Ltd.) was performed to form a 15 μm thick copper layer on the inner wall of the via hole hole, and the lower copper wiring and the copper foil on the surface were connected.

Finally, a copper foil was patterned according to a conventional method to form an upper layer copper wiring, whereby a wiring board with a built-in semiconductor chip was produced.

The obtained wiring board with a built-in semiconductor chip was measured and evaluated for laser processability, adhesion between the insulating layer and the cured epoxy resin layer, warpage, and plating property, as described below. The obtained results are shown in Tables 1 and 2.

Laser Machinability Holes for via holes formed by laser machining were vertically cut, and the cut surface was observed with an optical microscope. The case where no scooping occurred was judged to be good, and was marked as “◯” in the table. If a cut-out occurs, it is judged as a defect and "X" in the table
It was described.

Adhesion RCC was peeled off from the insulating layer in the direction of 90 degrees at a speed of 50 mm / min. The force (N / cm) required for peeling at that time was measured by a tensile tester.

A wiring board having an insulating layer formed in an area of 75 mm square in a glass epoxy base material of 120 mm square warp is placed on a flat surface plate,
The distance between the edge and the surface plate was measured. That distance (warpage)
Was less than 1 mm, it was determined to be good, and was described as “◯” in the table. When the warp was 2 mm or more, it was determined to be defective, and was described as “x” in the table. The case where the warp is between them, that is, 1 mm or more and less than 2 is described as “Δ” in the table.

The via holes after the plating of electroless plating was cut longitudinally, to observe the cut surface with an optical microscope. The case where the plating layer was formed was judged to be good, and was marked as “◯” in the table. The case where the plating layer was not formed was determined to be defective, and was marked as “x” in the table.

The components used in Tables 1 and 2 below are as follows. * 1: Bisphenol A type epoxy resin (EP828,
Yuka Shell Japan Co., Ltd. * 2: Methylhexahydrophthalic anhydride (B-650,
Dainippon Ink and Chemicals, Inc. * 3: Imidazole-based curing agent (2MZ-A, Shikoku Kasei Co., Ltd.) * 4: Synergist-based dispersant (Solspers 5000, Abyssia Chemical) * 5: Polymeric dispersant (Solspers 24000) , Abisia Chemical Co., Ltd. * 6: Epoxy silane (A-186, Nippon Unicar Co., Ltd.) * 7: Dimethyl silicone oil (KF-96, Shin-Etsu Chemical Co., Ltd.) * 8: Spherical silica (SO-C2, Tatsumori Co., Ltd.), Average particle size =
Filler content of 0.5 μm and particle size of 64 μm or more = 0% * 9: Spherical silica (EB-6D, manufactured by Denki Kagaku Kogyo Co., Ltd.), average particle size = 4.2 μm, filler content of particle size of 64 μm or more = 0% * 10: Spherical silica (MSR-25, Tatsumori Co., Ltd.), average particle diameter = 27 μm, filler content with particle diameter of 64 μm or more = 11.1.
5% (SO-EI, Tatsumorisha) * 11: Spherical silica (SO-EI, Tatsumorisha), average particle size =
Filler content of 0.3 μm, particle size of 64 μm or more = 0% * 12: Spherical silica (FB-24R, Denki Kagaku Kogyo Co., Ltd.),
Average particle size = 17.2 μm, filler content of particle size 64 μm or more = 5.5%

[0045]

[Table 1] (Formulation list) Example components 1 2 3 4 5 6 (parts by weight) Epoxy resin * 1 10 10 10 15 10 10 Curing agent * 2 10 10 10 15 10 10 Curing aid * 3 0.2 0.2 0.2 0.3 0.2 0.2 Dispersant A * 4 0.1 − − 0.08 0.1 0.1 Dispersant B * 5 − 0.4 − − − − Silane coupling agent * 6 − − 5 − − − Silicone oil * 7 − − − − − − Silica filler A * 8 20 20 20 15 − − Silica filler B * 9 60 60 60 55 −50 Silica filler C * 10 − − − − − 30 Silica filler D * 11 − − − − 80 − Silica filler E * 12 − − − − − − Total 100.3 100.6 105.2 100.38 100.3 100.3 Filler average particle size (μm) 3.3 3.3 3.3 3.4 0.3 12.8 Filler with particle size of 64 μm or more (%) 0 0 0 0 0 3.48 Viscosity (mPa / S; γ = 100s ^-1 ) 70,69,000 30,000 100,000 Laser processability ○ ○ ○ ○ ○ ○ Adhesion (N / cm) 15 15 15 15 15 15 Warpage ○ ○ ○ △ ○ ○ Plating property ○ ○ ○ ○ ○ ○

[0046]

[Table 2] (Combination table) Comparative example components 1 2 3 4 5 6 (parts by weight) Epoxy resin * 1 10 10 10 23 10 10 Curing agent * 2 10 10 10 22 10 10 Curing aid * 3 0.2 0.2 0.2 0.35 0.2 0.2 Dispersant A * 4 0.1 0.1 0.1 0.08 − − Dispersing agent B * 5 − − − − − − Silane coupling agent * 6 − − − − − − Silicone oil * 7 − − − − 0.1 − Silica filler A * 8 − − − 10 20 20 Silica filler B * 9 20 − − 45 60 60 Silica filler C * 10 60 50 7 − − − Silica filler D * 11 − 30 − − − − Silica filler E * 12 − − 73 − − − Total 100.3 100.3 100.3 100.43 100.3 100.2 Filler average particle size (μm) 21.3 17.0 18.2 3.5 3.3 3.3 Filler with particle size of 64 μm or more (%) 6.9 5.8 5.1 0 0 0 Viscosity (mPa / S; γ = 100s ^-1 ) 30 40,000 180,160,000 Laser processability × × × ○ ○ ○ Warp ○ ○ ○ × ○ ○ Plating property ○ ○ ○ ○ × ○

As shown in Tables 1 and 2, the insulating resin compositions of Examples 1 to 6 gave good results for all evaluation items including laser processability.

The results of Example 3 show that the use of the silane coupling agent has a small effect of reducing the viscosity of the insulating resin composition. Further, from the results of Example 4 and Comparative Example 4, it can be seen that when the content of filler is reduced, warpage tends to occur. From the results of Example 5, it can be seen that the viscosity of the insulating resin composition tends to increase as the average particle size of the filler decreases. Further, from the results of Comparative Examples 1 to 3, it can be seen that when the content of the filler having a particle diameter of 64 μm or more exceeds 5%, engraving occurs due to the laser processing and the laser processability deteriorates. Further, it is found that when silicone oil is used, plating does not deposit on the inner surface of the through hole. From the results of Comparative Example 6, it can be seen that the viscosity of the insulating resin composition increases too much unless a dispersant is used.

[0049]

According to the present invention, excellent laser processability can be imparted to an insulating resin composition for sealing which can be used for a wiring board with a built-in electronic component. In addition, it is possible to suppress the occurrence of warpage of the electronic component built-in wiring board. Further, by making the silicone oil free, the plating property can be improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a wiring board with a built-in electronic component of the present invention.

FIG. 2 is a manufacturing process diagram of a wiring board with a built-in electronic component of the present invention.

FIG. 3 is a schematic sectional view of a conventional wiring board with built-in electronic components.

FIG. 4 is an explanatory diagram of an engraving that occurs during laser processing of a conventional wiring board with built-in electronic components.

[Explanation of symbols]

1 1st base material, 2 1st wiring, 3 1st wiring board, 4
Electronic parts, 5 insulating layers, 6 second base material, 7 second wiring,
8 second wiring board, 9 via holes, 10 solder resist layer, 11 anisotropic conductive adhesive film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/31 H05K 3/46 Q H05K 3/46 T H01L 23/30 R (72) Inventor Yoshii Fujii 18 Satsuki-cho, Kanuma-shi, Tochigi Sony Chemical Co., Ltd. (72) Inventor Kaori Seki 18 Satsuki-cho, Kanuma-shi, Tochigi Sony Chemical Co., Ltd. F-term (reference) 4J002 AA021 CD011 CD051 CD061 CD101 DJ016 FD140 FD150 GQ01 4M109 AA01 BA03 EB11 5E346 AA05 AA12 AA15 AA17 AA26 AA32 AA38 AA43 BB01 CC02 CC08 CC09 CC32 DD02 DD03 DD32 EE02 EE06 EE07 FF04 FF45 GG19 GG22 GG28 GG40 HH11 5G303 AA07 AA08 AB20 BA12 CA09 CA11 5G305 BA13 A13 A40

Claims (7)

[Claims] 1. An insulating resin composition comprising a non-conductive filler dispersed in a thermosetting component, wherein the non-conductive filler has an average particle size of 0.3 to 20 μm, and all non-conductive fillers are contained. The insulating resin composition is characterized in that the proportion of the non-conductive filler having a particle diameter of 64 μm or more in the above is 5.0% by weight or less. 2. The non-conductive filler has an average particle size of 3 to 15.
The insulating resin composition according to claim 1, which has a thickness of μm. 3. The content of the non-conductive filler is 60 to 90.
The insulating resin composition according to claim 1, wherein the insulating resin composition has a weight percentage. 4. The insulating resin composition according to claim 1, which contains no silicone oil. 5. A first wiring substrate having a first wiring formed on at least one surface of a first base material, an electronic component connected to the first wiring on the first wiring substrate, and the electronic component. The insulating layer to be sealed, the second wiring substrate provided on the insulating layer, and having the second wiring formed on at least one surface of the second base material, are connected to the first wiring and the second wiring. With a via hole
A wiring board having a built-in electronic component, wherein the insulating layer is formed of an insulating resin composition in which a non-conductive filler is dispersed in a thermosetting component,
An electron characterized in that the non-conductive filler has an average particle size of 0.3 to 20 μm, and the proportion of the non-conductive filler having a particle size of 64 μm or more in all non-conductive fillers is 5.0% by weight or less. Wiring board with built-in components. 6. The electronic component built-in wiring board according to claim 5, wherein the second wiring of the second substrate is an outer surface of the electronic component built-in wiring board. 7. The wiring board with a built-in electronic component according to claim 5, wherein the electronic component is a semiconductor chip.