JP2019179792A - Prepreg, core material, and interposer - Google Patents

Abstract

To provide a prepreg for a core material used for forming a substrate for mounting a semiconductor element with excellent heat dissipation.SOLUTION: The prepreg is used for a core material used for forming a substrate for mounting a semiconductor element, A fiber base material is impregnated with a thermosetting resin composition containing a heat conductive filler. A thermally conductive filler contains an anisotropic first inorganic filler and a second inorganic filler having a spherical or irregular shape.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a prepreg, a core material, and an interposer.

  Various studies have been made on semiconductor devices so far. As this type of technology, for example, the one described in Patent Document 1 is known. Patent Document 1 describes a semiconductor device including a circuit board on which a semiconductor chip is mounted on an interposer and connected to a surface of the interposer opposite to the semiconductor chip via a connection terminal.

JP 2014-222703 A

  However, as a result of studies by the present inventors, it has been found that the semiconductor device described in Patent Document 1 has room for improvement in terms of heat dissipation.

In recent years, miniaturization of semiconductor chips and advancement of packaging density have been promoted, and high output semiconductor chips such as power semiconductors have been developed. In such a development environment, the required level of heat dissipation for semiconductor chips is increasing.
Based on the development environment described above, the present inventor conducted a heat conduction simulation of a substrate for mounting a semiconductor element using the following heat conduction calculation model. Specifically, it is as follows.

Heat conduction calculation model:
・ The chip is used as a heat source, and the amount of heat is set to 1W.
・ Calculate PKG temperature distribution and chip temperature in steady state.
・ 2.5 dimensions, adopting the symmetrical model shown in Fig. 1.
・ Set the depth length to 13mm so that the chip temperature of level 1 is 150 ℃.
・ It is assumed that the surface of each member exchanges heat with still air having an ambient temperature of 50 ° C.
Table 1 shows physical property values of each member (chip, solder, via, main board, interposer) of the PKG (package) of the heat conduction calculation model.

  Moreover, the chip | tip temperature (average temperature) of each level was computed using each of the levels 1-5 shown in following Table 2 about the thermal conductivity (W / m * K) of an interposer. The calculation results are shown in FIG.

  As a result of the simulation shown in FIG. 2, as the thermal conductivity of the interposer, the chip average temperature is lower in the planar direction (X direction) than in the thickness direction (Y direction). Thus, it was found that it contributes to the heat dissipation of the semiconductor chip. In particular, among the three levels 3 to 5 having the same total thermal conductivity, it was found that level 4 with X / Y of 5 is suitable as an interposer.

As the interposer, a general silicon interposer is known, but studies on a resin-made core material containing a fiber base material have been underway.
However, when a resin core material is used as an element mounting substrate for mounting a semiconductor chip such as an interposer or main board, a material having low thermal conductivity (such as a glass fiber substrate) is used for the fiber substrate. Therefore, the thermal conductivity in the thickness direction of the core material is lowered.

  As a result of studying the heat conduction characteristics of such a resin core material, if the thermal conductivity in the plane direction of the core material can be increased from the above knowledge, an element using this core material The present inventor has considered that the heat dissipation of the semiconductor chip can also be improved in the mounting substrate.

  The present inventor conducted further research based on such knowledge, and found that a resin-made core material using a prepreg obtained by impregnating a fiber base material with a thermosetting resin composition containing an anisotropically-shaped thermally conductive filler. It is possible to make the thermal conductivity in the plane direction of the core material relatively higher than that in the thickness direction by forming the core material, and heat dissipation of the semiconductor chip by using the core material as a mounting substrate As a result, the present invention has been completed.

According to the present invention,
A core material prepreg used for forming a substrate for mounting a semiconductor element,
The fiber base material is impregnated with a thermosetting resin composition containing a heat conductive filler,
There is provided a prepreg in which the thermally conductive filler includes a first inorganic filler having an anisotropic shape and a second inorganic filler having a spherical or irregular shape.

  Moreover, according to this invention, a core material provided with the hardened | cured material of the said prepreg is provided.

  Moreover, according to this invention, an interposer provided with the said core material and the penetration electrode which penetrates the said core material is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the core material prepreg used in order to form the board | substrate for mounting the semiconductor element excellent in heat dissipation, a core material using the same, and an interposer are provided.

It is a figure which shows the package structure used for the heat conduction calculation model. It is a figure which shows the chip | tip temperature of each level calculated by heat conduction simulation. It is sectional drawing which shows typically an example of a structure of the prepreg of this embodiment. It is sectional drawing which shows typically an example of a structure of the semiconductor device using the interposer of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate. Moreover, the figure is a schematic diagram and does not match the actual dimensional ratio.

An outline of the prepreg of the present embodiment will be described.
The prepreg of this embodiment is a core material prepreg used for forming a substrate for mounting a semiconductor element. This prepreg is obtained by impregnating a fiber base material with a thermosetting resin composition containing a thermally conductive filler. The thermally conductive filler in the prepreg can include a first inorganic filler having an anisotropic shape and a second inorganic filler having a spherical or irregular shape.

  According to this embodiment, by forming a resin core material using a prepreg formed by impregnating a fiber base material with a thermosetting resin composition containing an anisotropically-shaped thermally conductive filler, It is possible to make the thermal conductivity in the plane direction relatively higher than the thermal conductivity in the thickness direction.

  The core material of this embodiment can be suitably used as a mounting substrate (for example, an interposer) on which a semiconductor element is mounted. And the heat dissipation of a semiconductor chip can be improved by using the mounting substrate.

  Each component of the thermosetting resin composition of this embodiment is demonstrated.

(Thermosetting resin)
The thermosetting resin composition of this embodiment contains a thermosetting resin.
Examples of the thermosetting resin include an epoxy resin, a maleimide compound, and a benzoxazine compound. These may be used alone or in combination of two or more.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, and bisphenol M type epoxy resin (4,4 ′-(1,3-phenylenedioxide). Isopropylene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4 ′-(1,4-phenylenediisopridiene) bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4′-cyclohexene) Bisphenol type epoxy resins such as sidiene bisphenol type epoxy resins; phenol novolac type epoxy resins, cresol novolac type epoxy resins, tetraphenol group ethane type novolak type epoxy resins, and condensed ring aromatic hydrocarbon structures Novolak-type epoxy resins such as borac-type epoxy resins; biphenyl-type epoxy resins; aralkyl-type epoxy resins such as xylylene-type epoxy resins and biphenyl-aralkyl-type epoxy resins; phenol-aralkyl-type epoxy resins having a phenylene skeleton; Epoxy resins, phenol aralkyl type epoxy resins having a biphenylene skeleton, phenol aralkyl type epoxy resins such as a naphthol aralkyl type epoxy resin having a biphenylene skeleton; naphthylene ether type epoxy resins, naphthol type epoxy resins, naphthalene diol type epoxy resins, bifunctional Or naphthalene type epoxy such as tetrafunctional naphthalene type epoxy resin, binaphthyl type epoxy resin, naphthalene aralkyl type epoxy resin, etc. Fats; anthracene type epoxy resins; phenoxy type epoxy resin; dicyclopentadiene type epoxy resin; norbornene-type epoxy resin; adamantane type epoxy resin; fluorene type epoxy resins.

  As the epoxy resin, one of these may be used alone, two or more of them may be used in combination, and one or more of them may be used in combination with their prepolymer.

  Among the epoxy resins, bisphenol type epoxy resin, novolac type epoxy resin, biphenyl type epoxy resin, aralkyl type epoxy resin, naphthalene type epoxy resin, anthracene type from the viewpoint of further improving the heat resistance and insulation reliability of the obtained substrate One or more selected from the group consisting of epoxy resins and dicyclopentadiene type epoxy resins are preferable, and the group consisting of aralkyl type epoxy resins, novolak type epoxy resins having a condensed ring aromatic hydrocarbon structure and naphthalene type epoxy resins One or more selected from the above are more preferable.

  As the bisphenol A type epoxy resin, "Epicoat 828EL" and "YL980" manufactured by Mitsubishi Chemical Corporation can be used. As the bisphenol F type epoxy resin, “jER806H” and “YL983U” manufactured by Mitsubishi Chemical Corporation, “EPICLON 830S” manufactured by DIC Corporation, and the like can be used. As the bifunctional naphthalene type epoxy resin, “HP4032”, “HP4032D”, “HP4032SS” manufactured by DIC, and the like can be used. As the tetrafunctional naphthalene type epoxy resin, “HP4700” and “HP4710” manufactured by DIC, etc. can be used. As the naphthol type epoxy resin, “ESN-475V” manufactured by Nippon Steel Chemical Co., Ltd., “NC7000L” manufactured by Nippon Kayaku Co., Ltd. and the like can be used. As the aralkyl type epoxy resin, “NC3000”, “NC3000H”, “NC3000L”, “NC3000S”, “NC3000S-H”, “NC3100” manufactured by Nippon Kayaku Co., Ltd., “ESN-170” manufactured by Nippon Steel Chemical Co., Ltd. And “ESN-480” can be used. As the biphenyl type epoxy resin, “YX4000”, “YX4000H”, “YX4000HK”, “YL6121”, etc. manufactured by Mitsubishi Chemical Corporation can be used. As the anthracene type epoxy resin, “YX8800” manufactured by Mitsubishi Chemical Corporation can be used. As the naphthylene ether type epoxy resin, “HP6000”, “EXA-7310”, “EXA-7311”, “EXA-7311L”, “EXA7311-G3” and the like manufactured by DIC can be used.

  Among these epoxy resins, aralkyl type epoxy resins are particularly preferable. Thereby, the moisture absorption solder heat resistance and flame retardance of the board | substrate obtained can be improved further.

  The aralkyl type epoxy resin is represented by the following general formula (1), for example.

（上記一般式（１）中、ＡおよびＢは、ベンゼン環、ビフェニル構造等の芳香族環を表す。またＡおよびＢの芳香族環の水素が置換されていてもよい。置換基としては、例えば、メチル基、エチル基、プロピル基、フェニル基等が挙げられる。ｎは繰返し単位を表し、例えば、１〜１０の整数である。）

(In the above general formula (1), A and B represent an aromatic ring such as a benzene ring or a biphenyl structure. Hydrogen in the aromatic ring of A and B may be substituted. For example, a methyl group, an ethyl group, a propyl group, a phenyl group, etc. are mentioned, n represents a repeating unit, for example, is an integer of 1-10.)

  Specific examples of the aralkyl type epoxy resin include the following formulas (1a) and (1b).

（式（１ａ）中、ｎは、１〜５の整数を示す。）

(In formula (1a), n represents an integer of 1 to 5)

（式（１ｂ）中、ｎは、１〜５の整数を示す。）

(In formula (1b), n represents an integer of 1 to 5)

  As the epoxy resin other than the above, a novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure is preferable. Thereby, heat resistance and low thermal expansibility can further be improved.

  The novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure is a novolak type epoxy resin having a naphthalene, anthracene, phenanthrene, tetracene, chrysene, pyrene, triphenylene, tetraphen, or other condensed ring aromatic hydrocarbon structure. . The novolac type epoxy resin having a condensed ring aromatic hydrocarbon structure is excellent in low thermal expansion because a plurality of aromatic rings can be regularly arranged. Moreover, since the glass transition temperature is also high, it is excellent in heat resistance. Furthermore, since the molecular weight of the repeating structure is large, the flame retardancy is excellent as compared with the conventional novolac type epoxy resin.

  The novolak type epoxy resin having a condensed ring aromatic hydrocarbon structure is obtained by epoxidizing a novolac type phenol resin synthesized from a phenol compound, an aldehyde compound, and a condensed ring aromatic hydrocarbon compound.

  The phenol compound is not particularly limited, and examples thereof include phenol; cresols such as o-cresol, m-cresol, and p-cresol; 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2, Xylenols such as 6-xylenol, 3,4-xylenol and 3,5-xylenol; Trimethylphenols such as 2,3,5 trimethylphenol; Ethyl such as o-ethylphenol, m-ethylphenol and p-ethylphenol Phenols; alkylphenols such as isopropylphenol, butylphenol and t-butylphenol; phenylphenols such as o-phenylphenol, m-phenylphenol and p-phenylphenol; 1,5-dihydroxynaphthalene and 1,6-dihydroxynaphthalene , 2,7-naphthalene diols dihydroxy naphthalene; resorcinol, catechol, hydroquinone, pyrogallol, polyhydric phenols such as fluoro Guru Singh; alkylresorcin, alkylcatechol, alkyl polyhydric phenols and alkyl hydroquinone. Of these, phenol is preferable from the viewpoint of cost and the effect on the decomposition reaction.

  The aldehyde compound is not particularly limited, for example, formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, Examples include benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, dihydroxybenzaldehyde, trihydroxybenzaldehyde, 4-hydroxy-3-methoxyaldehyde paraformaldehyde and the like.

  The condensed ring aromatic hydrocarbon compound is not particularly limited, but for example, naphthalene derivatives such as methoxynaphthalene and butoxynaphthalene; anthracene derivatives such as methoxyanthracene; phenanthrene derivatives such as methoxyphenanthrene; other tetracene derivatives; chrysene derivatives; pyrene derivatives; A triphenylene derivative; a tetraphen derivative and the like.

  The novolak-type epoxy resin having a condensed ring aromatic hydrocarbon structure is not particularly limited. For example, methoxynaphthalene-modified orthocresol novolak epoxy resin, butoxynaphthalene-modified meta (para) cresol novolak epoxy resin, and methoxynaphthalene-modified novolak epoxy resin Etc. Among these, a novolac type epoxy resin having a condensed ring aromatic hydrocarbon structure represented by the following general formula (V) is preferable.

(In the above general formula (V), Ar is a condensed ring aromatic hydrocarbon group, Rs may be the same or different from each other, hydrogen atom; hydrocarbon group having 1 to 10 carbon atoms; halogen An element; an aryl group such as a phenyl group or a benzyl group; and a group selected from organic groups including glycidyl ether, wherein n, p, and q are integers of 1 or more, and the values of p and q are determined for each repeating unit. May be the same or different.)
Further, Ar in the formula (V) may have a structure represented by (Ar1) to (Ar4) in the following formula (VI).

(Rs in the above formula (VI) may be the same as or different from each other; a hydrogen atom; a hydrocarbon group having 1 to 10 carbon atoms; a halogen element; an aryl group such as a phenyl group or a benzyl group; And a group selected from organic groups including glycidyl ether.)

Further, as the epoxy resin other than the above, naphthalene type epoxy resins such as naphthol type epoxy resin, naphthalene diol type epoxy resin, bifunctional to tetrafunctional naphthalene type epoxy resin, naphthylene ether type epoxy resin and the like are preferable. Thereby, the heat resistance and low thermal expansibility of the printed wiring board to be obtained can be further improved. Here, the naphthalene type epoxy resin refers to one having a naphthalene ring skeleton and having two or more glycidyl groups.
Further, since the π-π stacking effect of the naphthalene ring is higher than that of the benzene ring, the naphthalene type epoxy resin is particularly excellent in low thermal expansion and low thermal shrinkage. Further, since the polycyclic structure has a high rigidity effect and the glass transition temperature is particularly high, the change in heat shrinkage before and after reflow is small. As a naphthol type epoxy resin, for example, the following general formula (VII-1), as a naphthalene diol type epoxy resin, the following formula (VII-2), as a bifunctional or tetrafunctional naphthalene type epoxy resin, the following formula (VII-3) As (VII-4) (VII-5) and a naphthylene ether type epoxy resin, it can show by the following general formula (VII-6), for example.

（ｎは平均１以上６以下の数を示し、Ｒはグリシジル基または炭素数１以上１０以下の炭化水素基を示す。）

(N represents an average number of 1 to 6, and R represents a glycidyl group or a hydrocarbon group having 1 to 10 carbon atoms.)

（式中、Ｒ^１は水素原子またはメチル基を表し、Ｒ^２はそれぞれ独立的に水素原子、炭素原子数１〜４のアルキル基、アラルキル基、ナフタレン基、またはグリシジルエーテル基含有ナフタレン基を表し、ｏおよびｍはそれぞれ０〜２の整数であって、かつｏまたはｍの何れか一方は１以上である。）

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aralkyl group, a naphthalene group, or a glycidyl ether group-containing naphthalene group. , O and m are each an integer of 0 to 2, and either o or m is 1 or more.)

  Although the lower limit of the weight average molecular weight (Mw) of an epoxy resin is not specifically limited, Mw300 or more may be sufficient, Preferably it is good also as Mw800 or more. It can suppress that tackiness arises in the hardened | cured material of a resin film as Mw is more than the said lower limit. The upper limit value of Mw is not particularly limited, but may be Mw 20,000 or less, and preferably Mw 15,000 or less. When Mw is not more than the above upper limit value, the handling property is improved and it becomes easy to form a resin film. The Mw of the epoxy resin can be measured by GPC, for example.

  The lower limit of the content of the epoxy resin (thermosetting resin) is preferably 3% by weight or more, preferably 4% by weight or more with respect to 100% by weight of the entire thermosetting resin composition (total solid content excluding the solvent). More preferred is 5% by weight or more. Thereby, handling property improves and it becomes easy to form the resin film which becomes a thermosetting resin composition. On the other hand, the upper limit of the content of the epoxy resin (thermosetting resin) is not particularly limited with respect to the entire thermosetting resin composition (total solid content excluding the solvent), but is preferably, for example, 50% by weight or less. 40% by weight or less is more preferable, and 30% by weight or less is more preferable. When the content of the epoxy resin is not more than the above upper limit value, the strength and flame retardancy of the obtained substrate may be improved, the linear expansion coefficient of the substrate may be reduced, and the warp reduction effect may be improved.

  In the present embodiment, the solid content of the resin composition refers to the non-volatile content in the resin composition, and refers to the remainder excluding volatile components such as water and solvent. Content with respect to the whole solid content of a resin composition refers to content with respect to the whole solid content (100 weight%) except the solvent of a resin composition, when a solvent is included.

The thermosetting resin composition of this embodiment contains a heat conductive filler.
The thermally conductive filler includes a first inorganic filler having an anisotropic shape and a second inorganic filler having a spherical or irregular shape.

  As the anisotropic first inorganic filler, a plate-like or scale-like inorganic filler can be used. These may be used alone or in combination of two or more.

  According to the knowledge of the present inventor, by using the anisotropic first inorganic filler as the thermal conductive filler, the thermal conductivity in the in-plane direction of the core material is relative to the thermal conductivity in the thickness direction. Can be enhanced. That is, by increasing the content ratio of the first inorganic filler having an anisotropic shape with respect to the entire heat conductive filler, the heat conduction in the plane direction of the core material compared with the case where only the second inorganic filler having a spherical or irregular shape is used. That is, it is possible to improve the planar anisotropy of thermal conductivity.

  Moreover, as a heat conductive filler, it is compared with the case where only the anisotropically-shaped first inorganic filler is used by using the anisotropically-shaped first inorganic filler and the spherical or irregular-shaped second inorganic filler in combination. Thus, it is possible to increase the filling of the heat conductive filler in the thermosetting resin composition. Thereby, thermal conductivity can be improved. Moreover, since the impregnation property of the thermosetting resin composition with respect to a fiber base material can be improved, the prepreg excellent in manufacturing stability is realizable. Moreover, generation | occurrence | production of a void can be suppressed and the prepreg excellent in the moldability is realizable.

  The lower limit of the aspect ratio of the first inorganic filler is, for example, 2 or more, preferably 3 or more, and more preferably 5 or more. Thereby, the heat conductivity in the plane direction of a core material can be improved. On the other hand, the upper limit of the aspect ratio of the aspect ratio of the first inorganic filler is not particularly limited, but may be, for example, 100 or less, 80 or less, or 50 or less. Thereby, since compatibility can be improved, the resin film excellent in film forming property can be obtained. Moreover, the laser via processability with respect to the hardened | cured material of a resin film can be improved.

  In addition, the aspect ratio in the case of plate shape or scale shape is represented by the maximum diameter / thickness.

  As the second inorganic filler, a spherical or indeterminate (polyhedral) inorganic filler can be used. These may be used alone or in combination of two or more.

The lower limit value of the average particle diameter of the second inorganic filler having a spherical or irregular shape (polyhedral shape) is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.05 μm or more. Thereby, it can suppress that the viscosity of a varnish becomes high, and can improve workability | operativity at the time of preparation of a resin film. Moreover, the upper limit of the average particle diameter of the spherical or amorphous second inorganic filler is not particularly limited, but is preferably 10.0 μm or less, more preferably 8.0 μm or less, and even more preferably 5.0 μm or less. Thereby, phenomena, such as sedimentation of a heat conductive filler, can be suppressed in a varnish, and a more uniform resin layer can be obtained.
The average particle diameter of the second inorganic filler having a spherical or irregular shape is measured by, for example, measuring the particle size distribution of the particles on a volume basis with a laser diffraction particle size distribution analyzer (LA-500, manufactured by HORIBA), and the median diameter (D ₅₀ ) can be the average particle size.

  The thermal conductive filler can include, for example, a high thermal conductive filler having a thermal conductivity of 20 W / m · K or more. Such a high thermal conductive filler of 20 W / m · K or more can contain at least one selected from alumina, aluminum nitride, boron nitride, silicon nitride, and magnesium oxide. These may be used alone or in combination of two or more. Thereby, the thermal conductivity of a core material can be improved.

  As an example of the combination of the heat conductive fillers, for example, a material in which the first inorganic filler contains plate-like boron nitride and the second inorganic filler contains spherical or amorphous alumina can be used. Thereby, the improvement of the heat conductivity of the planar direction of a core material and the high filling of a heat conductive filler are realizable.

  The lower limit of the content of the heat conductive filler (in the case of a plurality of heat conductive fillers, the total value of the respective contents) is, for example, 100% by weight of the total solid content of the thermosetting resin composition. 50% by weight or more, preferably 55% by weight or more, and more preferably 60% by weight or more. Thereby, the thermal conductivity of a core material can be improved. On the other hand, the upper limit of the content of the heat conductive filler is not particularly limited with respect to 100% by weight of the total solid content of the thermosetting resin composition, but may be 90% by weight or less, for example, 85% by weight. % Or less, or 80% by weight or less. Thereby, the manufacturing stability of a prepreg and the workability of a core material can be improved.

  The lower limit of the content of the first inorganic filler having the anisotropic shape is, for example, 3% by weight or more, preferably 5% by weight or more, and more preferably 7% by weight with respect to the entire thermally conductive filler. % Or more. Thereby, the thermal conductivity of a core material can be improved. On the other hand, the upper limit of the content of the first inorganic filler having an anisotropic shape is, for example, 30% by weight or less, preferably 25% by weight or less, more preferably 20%, based on the entire thermally conductive filler. % By weight or less. Thereby, the high filling of a heat conductive filler is realizable. Moreover, the moldability of a prepreg can be improved.

  The lower limit of the total content of the first inorganic filler and the second inorganic filler is, for example, 50% by weight or more, preferably 80% by weight or more, based on the total content of the heat conductive filler, Preferably it is 95 weight% or more. Thereby, the thermal conductivity of a core material can be improved. On the other hand, the upper limit of the total content of the first inorganic filler and the second inorganic filler may be, for example, 100% by weight or less, and preferably 99% by weight or less, with respect to the entire thermally conductive filler.

  The heat conductive filler may have a filler content of less than 20 W / m · K, for example, 15% by weight or less, or 10% by weight or less. Examples of the filler of less than 20 W / m · K include silica.

  The content of silica in the thermally conductive filler may be 0% by weight or more with respect to 100% by weight of the thermally conductive filler, whereas it is 10% by weight or less, preferably 5% by weight or less, and more. Preferably it is 1 weight% or less. Thereby, it is possible to further improve the thermal conductivity of the core material.

  The said thermosetting resin composition may contain fillers (for example, organic resin particle, inorganic particle, etc.) other than the said heat conductive filler in the range which does not impair the effect of invention. At this time, the content of the thermally conductive filler is, for example, 90% by weight or more, preferably 95% by weight or more, and more preferably 99% by weight with respect to the whole filler in the thermosetting resin composition. Above, it may be 100% by weight or less.

The thermosetting resin composition of the present embodiment can contain a curing agent.
Examples of the curing agent include tertiary amine compounds such as benzyldimethylamine (BDMA) and 2,4,6-trisdimethylaminomethylphenol (DMP-30); 2-methylimidazole, 2-ethyl-4-methylimidazole (EMI24), 2-phenyl-4-methylimidazole (2P4MZ), 2-phenylimidazole (2PZ), 2-phenyl-4-methyl-5-hydroxyimidazole (2P4MHZ), 1-benzyl-2-phenylimidazole (1B2PZ) ) And the like; and catalyst-type curing agents such as Lewis acids such as BF ₃ complexes.
In addition, for example, aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA), m-phenylenediamine, p-phenylenediamine, o-xylenediamine, 4,4′- Diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, 4,4′- (P-phenylenediisopropylidene) dianiline, 2,2- [4- (4-aminophenoxy) phenyl] propane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3 , 3′-diethyl-5,5′-dimethyldiphenylmethane, 3 In addition to aromatic polyamines such as 3′-diethyl-4,4′-diaminodiphenylmethane, polyamine compounds including dicyandiamide (DICY), organic acid dihydrazide, etc .; hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA) Acid anhydrides including aromatic acid anhydrides such as alicyclic acid anhydrides such as, trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA); polysulfide, thioester, Polymercaptan compounds such as thioethers; Isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; polyaddition type curing agents such as organic acids such as carboxylic acid-containing polyester resins; 2,2′-methylenebis (4-ethyl-6- t ert-butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3- Methyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-butylhydroquinone, 1,3,5-tris (3,5-di-tert) Phenolic compounds such as -butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) trione can also be used.
Furthermore, for example, phenolic resin-based curing agents such as novolak-type phenolic resins and resol-type phenolic resins; urea resins such as methylol group-containing urea resins; and condensation-type curing agents such as melamine resins such as methylol group-containing melamine resins It may be used. These may be used alone or in combination of two or more.

The phenol resin-based curing agent is a monomer, oligomer, or polymer in general having two or more phenolic hydroxyl groups in one molecule, and its molecular weight and molecular structure are not particularly limited. For example, phenol novolak resin, cresol novolak Resins, naphthol novolak resins and other novolak type phenol resins; trifunctional methane type phenol resins and other multifunctional phenol resins; terpene modified phenol resins and dicyclopentadiene modified phenol resins and the like; phenylene skeleton and / or biphenylene skeleton Aralkyl-type resins such as phenol aralkyl resins having phenylene and / or naphthol aralkyl resins having a biphenylene skeleton; bisphenols such as bisphenol A and bisphenol F Compounds, and the like. These may be used alone or in combination of two or more. Of these, those having a hydroxyl equivalent weight of 90 g / eq or more and 250 g / eq or less may be used from the viewpoint of curability.
The weight average molecular weight of the phenol resin is not particularly limited, but may be a weight average molecular weight of 4 × 10 ^{2 to} 1.8 × 10 ³ , and preferably 5 × 10 ^{2 to} 1.5 × 10 ³ . By making the weight average molecular weight equal to or higher than the above lower limit value, problems such as tackiness occur in the prepreg, and by making the above upper limit value or less, the impregnation property to the fiber base material is improved at the time of prepreg production, A more uniform product can be obtained.
In the present specification, “to” represents that an upper limit value and a lower limit value are included unless otherwise specified.

  The lower limit of the content of the curing agent is not particularly limited with respect to 100% by weight of the total solid content of the thermosetting resin composition, but is preferably 0.01% by weight or more, for example, 0.05% by weight or more. More preferred is 0.2% by weight or more. By setting the content of the curing agent to the above lower limit value or more, the effect of promoting curing can be sufficiently exhibited. On the other hand, the upper limit of the content of the curing agent is not particularly limited with respect to 100% by weight of the total solid content of the thermosetting resin composition, but is preferably 15% by weight or less, and more preferably 10% by weight or less. 8% by weight or less is more preferable. The preservability of a prepreg can be improved more as content of a hardening | curing agent is below the said upper limit.

The thermosetting resin composition of the present embodiment can further contain a cyanate resin.
The cyanate resin is a resin having a cyanate group (—O—CN) in the molecule, and a resin having two or more cyanate groups in the molecule can be used. Such a cyanate resin is not particularly limited. For example, it can be obtained by reacting a halogenated cyanide compound with phenols or naphthols, and prepolymerizing by a method such as heating as necessary. Moreover, the commercial item prepared in this way can also be used.
By using cyanate resin, the linear expansion coefficient of the cured resin film can be reduced. Furthermore, the electrical properties (low dielectric constant, low dielectric loss tangent), mechanical strength, etc. of the cured resin film can be enhanced.

  Examples of the cyanate resin include novolak type cyanate resin; bisphenol type cyanate resin, bisphenol E type cyanate resin, bisphenol type cyanate resin such as tetramethylbisphenol F type cyanate resin; reaction of naphthol aralkyl type phenol resin and cyanogen halide. Naphthol aralkyl type cyanate resin obtained by the following: dicyclopentadiene type cyanate resin; biphenylalkyl type cyanate resin. Among these, novolak type cyanate resins and naphthol aralkyl type cyanate resins are preferable, and novolak type cyanate resins are more preferable. By using the novolac-type cyanate resin, the crosslink density of the cured product of the resin film is increased, and the heat resistance is improved.

  The reason for this is that the novolak cyanate resin forms a triazine ring after the curing reaction. Furthermore, it is considered that novolak-type cyanate resin has a high benzene ring ratio due to its structure and is easily carbonized. Moreover, the cured product of the resin film containing the novolak type cyanate resin has excellent rigidity. Therefore, the heat resistance of the cured resin film can be further improved.

  As a novolak-type cyanate resin, what is shown by the following general formula (I) can be used, for example.

  The average repeating unit n of the novolak type cyanate resin represented by the general formula (I) is an arbitrary integer. The average repeating unit n is not particularly limited, but is preferably 1 or more, and more preferably 2 or more. When the average repeating unit n is not less than the above lower limit, the heat resistance of the novolak cyanate resin is improved, and it is possible to suppress the demerization and volatilization of the low mer during heating. The average repeating unit n is not particularly limited, but is preferably 10 or less, more preferably 7 or less. It can suppress that melt viscosity becomes it high that n is below the said upper limit, and can improve the moldability of a resin film.

  As the cyanate resin, a naphthol aralkyl type cyanate resin represented by the following general formula (II) is also preferably used. The naphthol aralkyl type cyanate resin represented by the following general formula (II) includes, for example, naphthols such as α-naphthol or β-naphthol, p-xylylene glycol, α, α′-dimethoxy-p-xylene, 1,4 -It is obtained by condensing a naphthol aralkyl type phenol resin obtained by reaction with di (2-hydroxy-2-propyl) benzene or the like and cyanogen halide. The repeating unit n in the general formula (II) is preferably an integer of 10 or less. When the repeating unit n is 10 or less, a more uniform resin film can be obtained. In addition, intramolecular polymerization hardly occurs at the time of synthesis, the liquid separation property at the time of washing with water tends to be improved, and the yield can be prevented from decreasing.

（式中、Ｒはそれぞれ独立に水素原子またはメチル基を示し、ｎは１以上１０以下の整数を示す。）

(In the formula, each R independently represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more and 10 or less.)

  Moreover, cyanate resin may be used individually by 1 type, may use 2 or more types together, and may use 1 type, or 2 or more types, and those prepolymers together.

  The lower limit of the content of the cyanate resin is, for example, preferably 1% by weight or more, more preferably 2% by weight or more, and further more preferably 3% by weight or more with respect to 100% by weight of the total solid content of the thermosetting resin composition. preferable. Thereby, low linear expansion and high elastic modulus of the cured product of the resin film can be achieved. On the other hand, the upper limit of the content of the cyanate resin is not particularly limited with respect to 100% by weight of the total solid content of the thermosetting resin composition, but is preferably 30% by weight or less, and more preferably 25% by weight or less. 20% by weight or less is more preferable. Thereby, heat resistance and moisture resistance can be improved. Further, when the content of the cyanate resin is within the above range, the storage elastic modulus E ′ of the cured product of the resin film can be further improved.

  The thermosetting resin composition of this embodiment may contain a hardening accelerator, for example. Thereby, the sclerosis | hardenability of a thermosetting resin composition can be improved. As a hardening accelerator, what accelerates | stimulates hardening reaction of a thermosetting resin can be used, The kind is not specifically limited. In this embodiment, as a hardening accelerator, for example, zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, zinc octylate, bisacetylacetonate cobalt (II), trisacetylacetonate cobalt (III) Organic metal salts such as triethylamine, tributylamine, tertiary amines such as diazabicyclo [2,2,2] octane, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, Imidazoles such as 2-phenyl-4-ethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxyimidazole , Phenol, bisphe Lumpur A, phenolic compounds nonylphenol, acetic, benzoic acid, salicylic, organic acids such as p-toluenesulfonic acid, and one or more selected from an onium salt compound. Among these, it is more preferable to include an onium salt compound from the viewpoint of more effectively improving curability.

  Although the onium salt compound used as a hardening accelerator is not specifically limited, For example, the compound represented by following General formula (2) can be used.

（上記一般式（２）中、Ｐはリン原子、Ｒ^３、Ｒ^４、Ｒ^５およびＲ^６は、それぞれ、置換もしくは無置換の芳香環または複素環を有する有機基、あるいは置換もしくは無置換の脂肪族基を示し、互いに同一であっても異なっていてもよい。Ａ⁻は分子外に放出しうるプロトンを少なくとも１個以上分子内に有するｎ（ｎ≧１）価のプロトン供与体のアニオン、またはその錯アニオンを示す。）

(In the general formula (2), P is a phosphorus atom, R ³ , R ⁴ , R ⁵ and R ⁶ are each an organic group having a substituted or unsubstituted aromatic ring or heterocyclic ring, or a substituted or unsubstituted group. An aliphatic group, which may be the same or different from each other, A ⁻ represents an n (n ≧ 1) -valent proton donor anion having at least one proton that can be released to the outside of the molecule. Or a complex anion thereof.)

  The lower limit of the content of the curing accelerator may be, for example, 0.01% by weight or more, preferably 0.05% by weight or more with respect to 100% by weight of the total solid content of the thermosetting resin composition. It is good. By making content of a hardening accelerator more than the said lower limit, sclerosis | hardenability of a thermosetting resin composition can be improved more effectively. On the other hand, the upper limit of the content of the curing accelerator may be, for example, 5% by weight or less, preferably 1% by weight or less, with respect to 100% by weight of the total solid content of the thermosetting resin composition. By making content of a hardening accelerator into the said upper limit or less, the preservability of a thermosetting resin composition can be improved.

  The thermosetting resin composition of this embodiment may contain a coupling agent. The coupling agent may be added directly when preparing the thermosetting resin composition, or may be added in advance to the inorganic filler. By using a coupling agent, the wettability of the interface between the inorganic filler and each resin can be improved. Therefore, it is preferable to use a coupling agent, and the heat resistance of the cured resin film can be improved.

Examples of the coupling agent include silane coupling agents such as epoxy silane coupling agents, cationic silane coupling agents, and amino silane coupling agents, titanate coupling agents, and silicone oil type coupling agents. A coupling agent may be used individually by 1 type, and may use 2 or more types together.
Thereby, the wettability of the interface of an inorganic filler and each resin can be made high, and the heat resistance of the hardened | cured material of a resin film can be improved more.

  Various types of silane coupling agents can be used, and examples thereof include epoxy silane, amino silane, alkyl silane, ureido silane, mercapto silane, and vinyl silane.

  Specific examples of the compound include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, and N-β (aminoethyl) γ-amino. Propylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-6- (aminohexyl) 3-aminopropyltrimethoxysilane, N- (3- (trimethoxysilylpropyl) -1,3-benzenedimethanane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropylmethyldimethoxysilane, β- (3,4- (Epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinyltriethoxysilane, etc., and a combination of one or more of these. Of these, epoxy silane, mercapto silane, and amino silane are preferable, and as amino silane, primary amino silane or anilide silane is more preferable.

  The addition amount of the coupling agent can be appropriately adjusted with respect to the specific surface area of the inorganic filler. The lower limit of the addition amount of such a coupling agent may be, for example, 0.01% by weight or more with respect to 100% by weight of the total solid content of the thermosetting resin composition, preferably 0.05% by weight. It is good also as above. When the content of the coupling agent is not less than the above lower limit value, the inorganic filler can be sufficiently covered, and the heat resistance of the cured product of the resin film can be improved. On the other hand, the upper limit of the addition amount of the coupling agent may be, for example, 5% by weight or less, preferably 3% by weight or less, with respect to 100% by weight of the total solid content of the thermosetting resin composition. When the content of the coupling agent is not more than the above upper limit value, it is possible to suppress the influence on the reaction, and it is possible to suppress a decrease in the bending strength or the like of the cured product of the resin film.

  The thermosetting resin composition of the present embodiment may contain components other than the above components as long as the object of the present invention is not impaired. Examples of other components include dyes such as green, red, blue, yellow, and black, pigments such as black pigments, colorants including one or more selected from the group consisting of pigments, low stress agents, antifoaming agents, Examples include leveling agents, ultraviolet absorbers, foaming agents, antioxidants, flame retardants, and ion scavengers. These may be used alone or in combination of two or more.

(Prepreg)
The prepreg of this embodiment is obtained by impregnating a fiber base material with the thermosetting resin composition.

  In this embodiment, as a known impregnation means, for example, a resin varnish is prepared by dissolving a thermosetting resin composition in a solvent, and a fiber substrate is immersed in the resin varnish. A method of applying to a fiber base material, a method of spraying the resin varnish onto the fiber base material by spraying, a resin film made of a thermosetting resin composition (a resin film formed by drying a thermosetting resin composition) as a fiber base material And a method of laminating on one side or both sides. At this time, the thermosetting resin composition in the prepreg can be in a B-stage state (semi-cured state).

In this embodiment, the varnish-like thermosetting resin composition can contain a solvent.
Examples of the solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve, carbitol, anisole, And organic solvents such as N-methylpyrrolidone. These may be used alone or in combination of two or more.

  When the thermosetting resin composition is varnished, the solid content of the thermosetting resin composition may be, for example, 50% by weight or more and 90% by weight or less, and more preferably 60% by weight or more and 80% by weight or less. It is good also as follows. Thereby, the thermosetting resin composition excellent in workability | operativity and film formability is obtained.

  The varnish-like thermosetting resin composition comprises the above-described components, for example, an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, and a rotation and revolution dispersion method. It can prepare by melt | dissolving in a solvent, mixing, and stirring using various mixers of these.

  FIG. 3 is a cross-sectional view schematically showing an example of the configuration of the prepreg. The prepreg 100 in FIG. 3 is formed by forming resin layers (first resin layer 102, second resin layer 103) made of a thermosetting resin composition on both sides of a fiber base material (fiber base material layer 101). is there. That is, this prepreg 100 has a structure in which a first resin layer 102, a fiber base layer 101 in which a fiber base material is impregnated with a thermosetting resin composition, and a second resin layer 103 are laminated in this order. Can have.

  As the fiber substrate, glass cloth can be used. Although it does not specifically limit as glass cloth, Glass fibers, such as a glass woven fabric and a glass nonwoven fabric, can be used. Thereby, a printed wiring board with low water absorption, high strength, and low thermal expansion can be obtained.

  Further, as the fiber substrate, other fiber substrates may be used instead of the glass cloth. Examples of other fiber base materials include polyamide resin fibers such as polyamide resin fibers, aromatic polyamide resin fibers and wholly aromatic polyamide resin fibers; polyester resin fibers, aromatic polyester resin fibers, wholly aromatic polyester resin fibers and the like. Polyester resin fibers; synthetic fiber base materials composed of woven or non-woven fabrics mainly composed of either polyimide resin fibers or fluororesin fibers; kraft paper, cotton linter paper, mixed paper of linter and kraft pulp, etc. And the like, and the like.

  Although the thickness of the said fiber base material is not specifically limited, Preferably it is 5 micrometers or more and 150 micrometers or less, More preferably, they are 10 micrometers or more and 100 micrometers or less, More preferably, they are 12 micrometers or more and 90 micrometers or less. By using the fiber base material having such a thickness, the handling property at the time of producing the prepreg can be further improved. When the thickness of the fiber base material is not more than the above upper limit, the impregnation property of the thermosetting resin composition in the fiber base material can be improved, and the occurrence of strand voids and a decrease in insulation reliability can be suppressed. Further, it is possible to facilitate formation of a through hole by a laser such as carbon dioxide, UV, or excimer. Moreover, the intensity | strength of a fiber base material or a prepreg can be improved as the thickness of a fiber base material is more than the said lower limit. As a result, handling properties can be improved, production of a prepreg can be facilitated, and warping of the resin substrate can be suppressed.

  Examples of the glass cloth include glass fibers formed of one or more kinds of glass selected from E glass, S glass, D glass, T glass, NE glass, UT glass, L glass, HP glass, and quartz glass. Are preferably used.

The lower limit of the bulk density of the fiber base material is, for example, 1.00 g / cm ³ or more, preferably 1.05 g / cm ³ or more. Thereby, the laser processability of an insulating layer can be improved. On the other hand, the upper limit of the bulk density of the fiber base material is, for example, 1.30 g / cm ³ or less, and preferably 1.25 g / cm ³ or less. Thereby, the impregnation property of a thermosetting resin composition can be improved. The bulk density of the fiber substrate can be adjusted, for example, by adjusting the number of warps and wefts to be driven and the thickness of the fiber that has been spread and flattened.

The lower limit of the air permeability of the fiber base material is, for example, 1 cc / cm ² / sec or more, and preferably 3 cc / cm ² / sec or more. Thereby, the impregnation property of a thermosetting resin composition can be improved. On the other hand, the upper limit value of the air permeability of the fiber base material is, for example, 80 cc / cm ² / sec or less, and preferably 50 cc / cm ² / sec. Thereby, the laser processability of an insulating layer can be improved.

The lower limit value of the basis weight of the fiber substrate is, for example, 10 g / m ² or more, and preferably 15 g / m ² or more. Thereby, the low thermal expansibility of a prepreg can be improved. On the other hand, the upper limit of the basic weight of the said fiber base material is 160 g / m < ² > or less, for example, Preferably it is 130 g / m < ² > or less. Thereby, the impregnation property of the thermosetting resin composition and the laser processability of the insulating layer can be improved.

The core material of the present embodiment includes the cured product of the prepreg.
This core material can be used as a substrate for mounting a semiconductor element. Examples of the substrate include a mounting substrate on which a semiconductor package such as an interposer or a main board is mounted. Among these, the core material of the present embodiment is suitable for an interposer that is electrically connected between a printed circuit board such as a main board (motherboard) and a semiconductor package.

  The lower limit value of the thermal conductivity X in the plane direction of the core material can be, for example, 3 W / mk or more, preferably 3.5 W / mk or more, more preferably 4 W / mk or more. Thereby, the heat dissipation of a semiconductor element can be improved. On the other hand, the upper limit value of the thermal conductivity X is not particularly limited, but may be, for example, 20 W / mk or less.

  In addition, the thermal conductivity ratio (X / Y) of the thermal conductivity X to the thermal conductivity Y in the thickness direction of the core material is, for example, 5 to 30, preferably 6 to 25, and more preferably 7 to 20. . Such a core material having thermal conductivity anisotropy can be suitably used for a substrate (especially an interposer) for mounting a semiconductor element, and can realize a substrate having excellent heat dissipation of the semiconductor element. is there.

  The interposer of the present embodiment is a resin interposer, and can include the core material and a through electrode penetrating the core material.

  In addition, a semiconductor device can be manufactured by using the interposer of this embodiment as a package substrate, mounting a semiconductor element on the package substrate, connecting, and sealing.

FIG. 4 is a diagram schematically showing an example of a mounting hierarchical structure of the semiconductor device 10 according to the present embodiment. The semiconductor device 10 is an electronic device in which a semiconductor package using the interposer 13 as a package substrate is mounted on the motherboard 11. Device.
Both surfaces of the mother board 11 are covered with solder resist layers 16a and 16b, but the connection terminals 15 of the outermost circuit on the semiconductor package connection side are exposed from the solder resist layer 16a.
The semiconductor package 12 is an area array type package in which the connection terminals 20b are arranged on the lower surface of the package. The connection terminals 20b on the lower surface of the package and the connection terminals 15 on the package mounting side of the mother board 11 are solder-connected by solder balls 22. Yes.

The semiconductor package 12 includes a semiconductor element 14 mounted on an interposer 13 that is a package substrate.
The interposer 13 is a multilayer printed wiring board. Three conductor circuit layers 18a, 18b, and 18c are sequentially stacked on the semiconductor element mounting side of the core substrate 17, and three conductor circuit layers 19a and 19b are also stacked on the motherboard connection side. , 19c are sequentially stacked. On the semiconductor element mounting side of the interposer 13, the wiring dimensions are reduced stepwise by passing through the three conductor circuit layers 18a, 18b, and 18c. The outermost layer circuits on both surfaces of the interposer 13 are covered with solder resist layers 21a and 21b, but the connection terminals 20a and 20b are exposed from the solder resist layers 21a and 21b.

The semiconductor element 14 has an electrode pad 23 on the lower surface, and the electrode pad 23 and the connection terminal 20 a of the outermost layer circuit on the semiconductor element mounting side of the interposer 13 are solder-connected by a solder ball 24.
A gap between the interposer 13 and the semiconductor element mounted thereon is sealed with a sealing material 25 such as an epoxy resin.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to description of these Examples at all.

[Preparation of thermosetting resin composition]
About the Example and the comparative example, the varnish-like thermosetting resin composition was prepared.
First, each component is dissolved or dispersed at a solid content ratio shown in Table 3, and adjusted so as to have a non-volatile content of 70% by weight with a mixed solvent of cyclohexanone and methyl isobutyl ketone, and stirred with a high-speed stirrer to be thermosetting. A resin composition (resin varnish) was prepared.
In addition, the numerical value which shows the mixture ratio of each component in Table 3 has shown the mixture ratio (weight%) of each component with respect to the whole solid content of a thermosetting resin composition.

In the examples and comparative examples, the following raw materials were used.
(Thermosetting resin)
Thermosetting resin 1: phenol aralkyl type epoxy resin having biphenylene skeleton (Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent: 275, weight average molecular weight: 2000)
(Curing agent)
Curing agent 1: phenolic resin-based curing agent (manufactured by Nippon Kayaku Co., Ltd., KAYAHARD GPH-103, hydroxyl group equivalent: 231)
(Cyanate resin)
Cyanate resin 1: Cyanate resin (Lonza Japan KK, PT-30, weight average molecular weight: 700)
(Thermal conductive filler)
First inorganic filler: Boron nitride (plate, Denka Co., GP, average particle size: 8 μm, aspect ratio: 8)
Second inorganic filler: Mixed product obtained by mixing the following polyhedral alumina 1 and the following polyhedral alumina 2 at 7: 3 (weight ratio) Polyhedral alumina 1 (α-alumina single crystal particles, average particle diameter: 3 μm, Circularity: 0.79, manufactured by Sumitomo Chemical Co., Sumiko Random AA-3)
Polyhedral alumina 2 (α-alumina single crystal particles, average particle size 0.4: μm, circularity: 0.79, manufactured by Sumitomo Chemical Co., Sumiko Random AA-04)
(Coupling agent)
Coupling agent 1: Epoxysilane coupling agent (GE Toshiba Silicone Co., Ltd., A-187)
(Additive)
Leveling agent 1: Acrylic resin (BYK-361N, manufactured by BYK-Chem Japan), polyacrylate surfactant

  About the obtained thermosetting resin composition, evaluation was implemented based on the following evaluation items.

(Thermal conductivity)
After applying the obtained thermosetting resin composition (resin varnish) onto a PET film as a carrier substrate using a comma coater, the solvent was removed at 150 ° C. for 3 minutes, and the thickness was 30 μm. A resin film was formed. Thereby, a resin film with a carrier was obtained.
Three of the obtained resin films with a carrier from which the PET film as a carrier substrate was peeled were laminated to prepare a resin sheet having a thickness of 90 μm. Next, the resin sheet was heat treated at 230 ° C. for 2 hours to obtain a sheet-like cured product.
The thermal conductivity of the sheet-like cured product obtained above was measured. The thermal conductivity X in the plane direction and the thermal conductivity Y in the thickness direction of the cured sheet were measured by the laser flash method. The evaluation results are shown in Table 3. The unit of thermal conductivity is W / m · K.

(Formability)
After applying the obtained thermosetting resin composition (resin varnish) to a copper foil as a carrier substrate using a comma coater, the solvent was removed at 150 ° C. for 3 minutes to obtain a resin film having a thickness of 30 μm. Formed. Thereby, a resin film with a carrier was obtained. Subsequently, the obtained resin film with carrier, glass woven fabric (cross type # 2116, T-glass, basis weight 104 g / m ² ), and resin film with carrier were laminated in this order, and resin of the resin film with carrier was obtained. A prepreg in a B-stage state was obtained by performing a vacuum press on the laminate in which the membrane was disposed toward the fiber base material.
Moreover, the core material (core layer) was obtained by hardening with respect to the obtained prepreg on condition of 230 degreeC and 2 hours.
The moldability was evaluated by assuming that no void was generated in the obtained core material, and x when the void was generated.

The thermosetting resin compositions of Examples 1 and 2 have higher heat conductivity in the planar direction than Comparative Examples 1 and 2, and the heat conductivity ratio in the planar direction with respect to the thickness direction is high, and thus excellent in heat dissipation. It was found that the core material can be realized.
In addition, since the prepregs of Examples 1 and 2 have a thermal conductivity ratio (X / Y) in the plane direction with respect to the thickness direction of 5 or more, it is applicable to the interposer in consideration of the result of the above-described thermal conduction simulation. It is expected that the heat dissipation of the semiconductor chip can be improved.

DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Mother board 12 Semiconductor package 13 Interposer 14 Semiconductor element 15 Connection terminal 16a, 16b Solder resist layer 17 Core board | substrate 18a, 18b, 18c Conductor circuit layer 19a, 19b, 19c Conductor circuit layer 20a Connection terminal 20b Connection terminal 21a, 21b Solder resist layer 22 Solder ball 23 Electrode pad 24 EMI
24 Solder balls 25 Sealing material 100 Prepreg 101 Fiber base layer 102 First resin layer 103 Second resin layer

Claims (16)

A core material prepreg used for forming a substrate for mounting a semiconductor element,
The fiber base material is impregnated with a thermosetting resin composition containing a heat conductive filler,
The prepreg in which the said heat conductive filler contains the 1st inorganic filler of anisotropic shape, and the 2nd inorganic filler of spherical shape or indefinite shape. The prepreg according to claim 1,
A prepreg in which the first inorganic filler includes a plate-like or scale-like one. The prepreg according to claim 1 or 2,
A prepreg in which the aspect ratio of the first inorganic filler is 2 or more and 20 or less. The prepreg according to any one of claims 1 to 3,
A prepreg comprising the thermally conductive filler having a thermal conductivity of 20 W / m · K or more. The prepreg according to claim 4,
The thermally conductive filler is a prepreg containing at least one selected from alumina, aluminum nitride, boron nitride, silicon nitride, and magnesium oxide. The prepreg according to any one of claims 1 to 5,
A prepreg in which the first inorganic filler includes plate-like boron nitride, and the second inorganic filler includes spherical or amorphous alumina. The prepreg according to any one of claims 1 to 6,
The prepreg whose content of the said heat conductive filler with respect to the whole solid of the said thermosetting resin composition is 50 to 90 weight%. The prepreg according to any one of claims 1 to 7,
The prepreg whose content of the said 1st inorganic filler with respect to the said whole heat conductive filler is 3 to 30 weight%. The prepreg according to any one of claims 1 to 8,
A prepreg in which the fiber base material includes a glass cloth. The prepreg according to any one of claims 1 to 9,
The prepreg whose content of the silica in the said heat conductive filler is 0 to 10 weight%. The prepreg according to any one of claims 1 to 10,
A prepreg in which the thermosetting resin composition is in a B-stage state. The prepreg according to any one of claims 1 to 11,
A prepreg in which a resin layer made of the thermosetting resin composition is formed on both sides of the fiber base material.   A core material provided with the hardened | cured material of the prepreg of any one of Claim 1-12. A core material used to form a substrate for mounting a semiconductor element,
The core material whose thermal conductivity X in a plane direction is 3 W / mk or more and 20 W / mk or less. The core material according to claim 14,
The core material whose thermal conductivity ratio of the said thermal conductivity X with respect to the thermal conductivity Y in the thickness direction is 5-30.   An interposer comprising the core material according to any one of claims 13 to 15 and a through electrode penetrating the core material.

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