JP6778889B2 - Prepreg, metal-clad laminate and printed wiring board - Google Patents

Description

The present invention relates to a prepreg, a metal-clad laminate and a printed wiring board.

Printed wiring boards are widely used in various fields such as electronic devices, communication devices, and computers. In recent years, in particular, small portable devices such as mobile communication terminals and notebook PCs are rapidly becoming multifunctional, high-performance, thin and compact. Along with this, the printed wiring boards used in these products are also required to have finer conductor wiring, multiple layers of conductor wiring layers, thinner thickness, and higher performance such as mechanical characteristics. In particular, as the thickness of the printed wiring board progresses, there is a problem that the semiconductor package in which the semiconductor chip is mounted on the printed wiring board is warped and mounting defects are likely to occur.

In order to suppress warpage of a semiconductor package in which a semiconductor chip is mounted on a printed wiring board, Patent Document 1 describes a metal-clad laminate having metal foils on both sides of an insulating layer containing an epoxy resin composition and a fiber base material. Therefore, the epoxy resin composition contains an epoxy resin, a bismaleimide compound, and an inorganic filler, and the degree of hysteresis of the dimensional change of the metal-clad laminate in the range of 30 ° C. to 260 ° C. is within a predetermined range. Zhang laminates are disclosed. Since this epoxy resin composition contains a bismaleimide compound and the degree of hysteresis is within a predetermined range, even if a large temperature change exceeding the glass transition temperature of the insulating layer occurs, the plane direction (XY direction) of the insulating layer It is disclosed that the average linear expansion coefficient calculated in the range of 30 to 260 ° C. is small, and the amount of warpage of a semiconductor device in which a semiconductor element is mounted on a printed wiring board at room temperature (23 ° C.) and 260 ° C. can be reduced.

JP-A-2015-63040

However, the metal-clad laminate described in Patent Document 1 has a problem that the warp of the semiconductor package cannot be sufficiently suppressed.

Therefore, it is an object of the present invention to provide a prepreg, a metal-clad laminate, and a printed wiring board that can reduce the amount of warpage of a semiconductor package due to a temperature change even if the thickness of the printed wiring board is thin.

The prepreg of the present invention is a prepreg comprising a base material of reinforcing fibers and a semi-cured product of a resin composition impregnated in the base material of the reinforcing fibers.
After curing, the glass transition temperature (Tg) is 220 ° C. or lower, and the dynamic storage elastic modulus at 260 ° C. is 10 GPa or less.
The resin composition contains (A) an epoxy resin, (B) a phenol resin, (C) a low elasticity component, and (D) an inorganic filler.
Wherein component (A), epoxy equivalent comprises der Ru epoxy resin or 180 g / eq,
The component (B), hydroxyl group equivalent comprises 180 g / eq or more 290 g / eq or less der Ru phenolic resin,
The content of the component (D) is 130 parts by mass or less with respect to a total of 100 parts by mass of the components (A) and (B).

The metal-clad laminate of the present invention is characterized by comprising a cured product of one cured product or a plurality of laminated products of the prepreg and a metal foil adhered to one side or both sides of the cured product.

The printed wiring board of the present invention is characterized by comprising a cured product of one cured product or a plurality of laminated products of the prepreg and conductor wiring provided on one side or both sides of the cured product.

According to the present invention, even if the thickness of the printed wiring board is thin, the amount of warpage of the semiconductor package due to a temperature change can be reduced.

Hereinafter, embodiments of the present invention will be described.

[Prepreg]
The prepreg according to the present embodiment (hereinafter, may be simply referred to as prepreg) includes a base material of reinforcing fibers and a semi-cured product of a resin composition impregnated in the base material of reinforcing fibers, and after curing, glass. The transition temperature (Tg) is 220 ° C. or lower, and the elastic modulus at 260 ° C. is 10 GPa or less. The resin composition contains (A) an epoxy resin, (B) a phenol resin, (C) a low elasticity component, and (D) an inorganic filler. The epoxy equivalent of the component (A) is 180 g / eq or more. The hydroxyl group equivalent of the component (B) is 180 g / eq or more. The content of the component (D) is 130 parts by mass or less with respect to a total of 100 parts by mass of the components (A) and (B). If the prepreg according to the present embodiment is used as a material for a semiconductor package in which a semiconductor chip is mounted on a printed wiring board, the thermal expansion coefficient of the cured product of the prepreg is within a predetermined range, and the elastic modulus of the cured product of the prepreg at 260 ° C. It is possible to effectively relieve the stress generated in the semiconductor chip and the printed wiring board and reduce the amount of warpage of the semiconductor package due to the temperature change without adjusting the resin composition so as to increase the value.

Here, the epoxy equivalent is the average mass number of the compound per epoxy group, and the epoxy equivalent described in the examples is a catalog value. The hydroxyl group equivalent is the average mass number of the compound per hydroxyl group, and the hydroxyl group equivalent described in Examples is a catalog value.

The glass transition temperature (Tg) of the cured product of the prepreg is 220 ° C. or lower, preferably 200 to 160 ° C., and more preferably 200 ° C. to 180 ° C.

The elastic modulus of the cured product of the prepreg at 260 ° C. is 10 GPa or less, preferably 5 GPa or less. If the elastic modulus of the cured product of the prepreg at 260 ° C. exceeds 10 GPa, there is a possibility that the semiconductor package will have a large amount of warpage due to a temperature change. Further, the coefficient of thermal expansion of the cured product of the prepreg at 260 ° C. is low, and the coefficient of thermal expansion (CTE (X, Y)) in the direction orthogonal to the thickness direction (in-plane direction) of the cured product of the prepreg is referred to. ) Is low, warpage of the semiconductor package due to temperature change can be further suppressed.

The elastic modulus of the cured product of the prepreg at 200 ° C. is preferably 10 GPa or less. If the elastic modulus of the cured product of the prepreg at 200 ° C. is within the above range, a semiconductor package having a smaller amount of warpage due to a temperature change can be obtained.

The CTE (X, Y) of the cured product of the prepreg is preferably 5 ppm / ° C. or less. When the CTE (X, Y) of the cured product of the prepreg is within the above range, a semiconductor package having a smaller amount of warpage due to a temperature change can be obtained.

The thickness of the prepreg may be appropriately selected according to the characteristics required by the intended use of the double-sided copper-clad laminate, and is preferably 0.010 to 0.200 mm. The resin content (content of the resin composition) of the prepreg is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the prepreg.

The glass transition temperature (Tg) of the cured product of the prepreg is 220 ° C. or lower, the elastic modulus at 260 ° C. is 10 GPa or less (elastic modulus at 200 ° C. is 10 GPa or less), and the CTE (X, Y) is 5 ppm / ° C. or less. For example, Examples 1 to 7 may be used.

[Semi-cured resin composition]
The semi-cured product of the resin composition is a semi-cured product of the resin composition.

(Epoxy resin (A))
The resin composition contains an epoxy resin (A). The epoxy resin (A) is not particularly limited as long as it is an epoxy resin having an epoxy equivalent of 180 g / eq or more, and is, for example, a bisphenol type such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol S type epoxy resin. Novolak type epoxy resin such as epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, xylylene type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, biphenyl novolac type epoxy resin, biphenyl Arylalkylene type epoxy resin such as dimethylene type epoxy resin, trisphenol methanenovolac type epoxy resin, tetramethylbiphenyl type epoxy resin, naphthalene type epoxy resin, naphthalene skeleton modified cresol novolac type epoxy resin, naphthalenediol aralkyl type epoxy resin, naphthol Naphthalene skeleton-modified epoxy resin such as aralkyl type epoxy resin, methoxynaphthalene-modified cresol novolac type epoxy resin, methoxynaphthalenedimethylene type epoxy resin, triphenylmethane type epoxy resin, anthracene type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type An epoxy resin, a fluorene type epoxy resin, a flame-retardant epoxy resin obtained by halogenating the above epoxy resin, or the like can be used. Only one of these may be used, or two or more of these may be used in combination. When the epoxy resin (A) is a combination of two or more kinds having different epoxy equivalents, the epoxy equivalent of the epoxy resin (A) is the epoxy equivalent for each epoxy resin and the epoxy with respect to the total mass of the epoxy resin (A). The product with the compounding ratio of the resin may be calculated and used as the sum of the calculated products.

The epoxy equivalent of the epoxy resin (A) is 180 g / eq or more, preferably 200 to 290 g / eq. If the epoxy equivalent is less than 180 g / eq, the crosslink density of the cured product of the resin composition becomes high, and the glass transition temperature of the cured product of the prepreg may exceed 220 ° C.

The resin composition may contain a thermosetting component in addition to the epoxy resin (A). Hereinafter, when the resin composition contains a thermosetting component, the epoxy resin (A) and the thermosetting component are referred to as a thermosetting resin. The thermosetting component is not particularly limited as long as it is a heat-curable resin, and for example, an imide resin, a cyanate ester resin, an isocyanate resin, a modified polyphenylene ether resin, a benzoxazine resin, an oxetane resin, or the like can be used. Only one of these may be used, or two or more thereof may be used in combination.

(Phenolic resin (B))
The resin composition contains a phenolic resin (B). The phenolic resin (B) functions as a curing agent for the epoxy resin (A), has good electrical properties, and has excellent toughness, flexibility, adhesive strength, and stress relaxation during heating. can do.

The phenolic resin (B) is not particularly limited as long as it is a phenolic resin having a hydroxyl group equivalent of 180 g / eq or more. Resins, bisphenol A novolak type phenol resins, naphthalene type phenol resins and the like can be used. Only one of these may be used, or two or more of these may be used in combination. When the phenolic resin is a combination of two or more kinds having different hydroxyl group equivalents, the hydroxyl group equivalent of the phenol resin (B) is the compounding of the hydroxyl group equivalent and the total mass of the phenol resin (B) for each phenol resin. The product with the ratio may be calculated and used as the sum of the calculated products.

The content ratio of the phenol resin (B) in the resin composition is preferably 40 to 120 parts by mass with respect to 100 parts by mass of the epoxy resin (A).

The hydroxyl group equivalent of the phenol resin (B) is 180 g / eq or more, preferably 200 to 290 g / eq. If the hydroxyl group equivalent is less than 180 g / eq, the crosslink density of the cured product of the resin composition may increase, and the glass transition temperature of the cured product of the prepreg may increase.

The resin composition may contain a curing agent in addition to the phenol resin (B). As the curing agent, for example, dicyandiamide or the like can be used.

(Low elastic component (C))
The resin composition contains a low elastic component (C). The material of the low elastic component (C) is not particularly limited as long as it is a component that can reduce the elastic modulus of the cured product of the prepreg in the temperature range of 30 to 260 ° C. For example, acrylic rubber, silicone rubber, and core shell. An elastomer such as rubber can be used. Only one of these may be used, or two or more thereof may be used in combination. Among them, the material of the low elasticity component (C) is preferably acrylic rubber.

As the acrylic rubber, it is preferable to use acrylic rubber (a) having a structure represented by the following formulas (1), (2) and (3).

x is 0 or an integer greater than 0. y is 0 or an integer greater than 0. z is 0 or an integer greater than 0 (unless x, y, z are all 0). In (2), R1 is a hydrogen atom or a methyl group, and R2 is a hydrogen atom or an alkyl group. In formula (3), R3 is a hydrogen atom or a methyl group, and R4 is at least one selected from -Ph (phenyl group), -COOCH ₂ Ph and -COO (CH ₂ ) ₂ Ph.

That is, the main chain of the acrylic rubber (a) has a structure represented by at least the formulas (2) and (3) of the formulas (1), (2) and (3). Preferably, an epoxy group is attached to the main chain.

When the main chain of the acrylic rubber (a) has a structure represented by the formulas (1), (2) and (3), it is represented by the formulas (1), (2) and (3). The arrangement order of the structures to be formed is not particularly limited. In this case, in the main chain of the acrylic rubber (a), the structures represented by the formula (1) may or may not be continuous, and the structures represented by the formula (2) may be continuous. May be continuous or non-continuous, and the structures represented by the above equation (3) may be continuous or non-continuous.

Even when the main chain of the acrylic rubber (a) has a structure represented by the formulas (2) and (3), the arrangement order of the structures represented by the formulas (2) and (3) is particularly limited. Not done. In this case, in the main chain of the acrylic rubber (a), the structures represented by the formula (2) may or may not be continuous, and the structures represented by the formula (3) may be continuous. May be continuous or non-continuous.

The structure represented by the formula (3) may have Ph (phenyl group), -COOCH ₂ Ph and -COO (CH ₂ ) ₂ Ph. The acrylic rubber (a) preferably does not have an unsaturated bond such as a double bond or a triple bond between carbon atoms. That is, it is preferable that the carbon atoms of the acrylic rubber (a) are bonded by a saturated bond (single bond). The weight average molecular weight (Mw) of the acrylic rubber (a) is preferably 200,000 to 850,000.

The content ratio of the low elastic component (C) is preferably 30 to 100 parts by mass with respect to 100 parts by mass in total of the epoxy resin (A) and the phenol resin (B). When the content ratio of the low elastic component (C) is within the above range, good warpage characteristics of the semiconductor package can be obtained.

(Inorganic filler (D))
The resin composition contains an inorganic filler (D). Examples of the inorganic filler (D) include silica such as fused silica (SiO ₂ ) and crystalline silica (SiO ₂ ), boehmite, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, talc, clay, and the like. Mica or the like can be used. Only one of these may be used, or two or more thereof may be used in combination.

The average particle size of the inorganic filler (D) is not particularly limited, and is preferably 0.5 to 2.0 μm, more preferably 0.5 to 1.0 μm. When the average particle size of the inorganic filler (D) is within the above range, the inorganic filler (D) having good moldability can be obtained. The average particle size of the inorganic filler (D) means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method.

The content of the inorganic filler (D) is 130 parts by mass or less, preferably 100 parts by mass or less, based on 100 parts by mass of the total of the epoxy resin (A) and the phenol resin (B). In the present embodiment, the content of the inorganic filler (D) is 130 parts by mass or less, and the glass transition temperature (Tg) of the cured product of the prepreg is 220 ° C. or less, so that the CTE (X, Y) is low. Moreover, it can be a cured product of a prepreg having a low elastic modulus at 260 ° C. Further, if the content of the inorganic filler (D) is more than 130 parts by mass, the semiconductor package may have a large amount of warpage due to a temperature change.

The resin composition may further contain a curing accelerator. As the curing accelerator, for example, an imidazole compound, an amine compound, a thiol compound, an organic acid metal salt such as a metal soap, or the like can be used. In addition to the above components, the resin composition may further contain a thermoplastic resin, a flame retardant, a colorant, a coupling agent, and the like.

[Method for preparing resin composition]
As a method for preparing the resin composition, for example, an epoxy resin (A), a phenol resin (B), a low elasticity component (C), an inorganic filler (D), and other components to be blended as necessary are predetermined. Examples thereof include a method of preparing a blending amount, blending these in an organic solvent, and further stirring and mixing. At this time, a component other than the inorganic filler (D) may be blended in an organic solvent to obtain a varnish-like base resin, and the obtained base resin may be blended with the inorganic filler (D). As the organic solvent, for example, ethers such as ethylene glycol monomethyl ether, acetone, methyl ethyl ketone (MEK), dimethylformamide, benzene, toluene and the like can be used.

[Reinforcing fiber base material]
The prepreg comprises a reinforcing fiber substrate. As the reinforcing fiber, for example, glass fiber, aromatic polyamide, liquid crystal polyester, poly (paraphenylene benzobisoxazole) (PBO), polyphenylene sulfide resin (PPS) and the like can be used, and among them, glass fiber can be used. preferable.

As the glass fiber, for example, E glass fiber, D glass fiber, S glass fiber, T glass fiber, NE glass fiber, quartz fiber (Q glass) and the like can be used. Among them, it is preferable to use at least one glass fiber selected from E glass fiber, T glass fiber, S glass fiber, NE glass fiber and quartz fiber (Q glass). As a result, a cured product of prepreg having excellent electrical insulation and dielectric properties can be obtained.

The surface of the reinforcing fiber may be modified with a coupling agent. As the coupling agent, for example, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like can be used.

Examples of the form of the base material of the reinforcing fiber include a woven fabric in which warp threads and weft threads are woven so as to be substantially orthogonal to each other, such as a plain weave; a non-woven fabric and the like. The thickness of the base material of the reinforcing fiber is preferably 15 to 100 μm.

[Prepreg manufacturing method]
As a method for producing a prepreg, for example, the above resin composition is impregnated into a base material of a reinforcing fiber to obtain a resin impregnated base material, and the obtained resin impregnated base material is heated and dried to obtain a solvent in the resin composition. Examples thereof include a method of semi-curing the resin composition by removing the resin composition. The temperature for heating and drying is preferably 110 to 140 ° C.

[Metal-clad laminate]
The metal-clad laminate of the present embodiment (hereinafter, may be referred to as a metal-clad laminate) is a cured product of one prepreg or a cured product of a plurality of laminates (hereinafter, may be referred to as a first insulating layer). And a metal foil adhered to one side or both sides of the cured product. That is, the structure of the metal-clad laminate is a two-layer structure consisting of a first insulating layer and a metal foil adhered to one side of the first insulating layer, or both sides of the first insulating layer and the first insulating layer. It has a three-layer structure with the bonded metal foil.

Since the first insulating layer is made of the cured product of the above prepreg, the material properties of the first insulating layer are equivalent to the material properties of the cured product of the above prepreg. That is, the first insulating layer has a glass transition temperature (Tg) of 220 ° C. or lower and an elastic modulus of 10 GPa or less at 260 ° C. Therefore, if the metal-clad laminate according to the present embodiment is used as the material of the semiconductor package, the amount of warpage of the semiconductor package due to the temperature change can be reduced.

The CTE (X, Y) of the first insulating layer is preferably 5 ppm / ° C. or less. When the CTE (X, Y) of the first insulating layer is within the above range, the metal-clad laminate includes the first insulating layer having a low CTE (X, Y) and a low elastic modulus at 260 ° C. Warpage is less likely to occur due to temperature changes.

The thickness of the metal-clad laminate is not particularly limited, and is preferably 20 to 400 μm.

As the metal foil, for example, copper foil, silver foil, aluminum foil, stainless steel foil and the like can be used, and among them, copper foil is preferably used. The thickness of the metal foil is preferably 2 to 12 μm.

As a method for manufacturing a metal-clad laminate, for example, a plurality of prepregs are laminated to obtain a laminate, and metal foils are arranged on one side or both sides of the obtained laminate to obtain a laminate with a metal foil. A method of heat-press molding a laminate with a metal foil to laminate and integrate the laminate; a prepreg with a metal foil is obtained by arranging the metal foil on one side or both sides of one prepreg, and the prepreg with the metal foil is used. Examples thereof include a method of heat-pressing molding and laminating and integrating. The conditions for heat and pressure molding are, for example, 140 to 220 ° C., 0.5 to 5.0 MPa, and 40 to 240 minutes.

[Printed circuit board]
The printed wiring board of the present embodiment (hereinafter referred to as a printed wiring board) includes a cured product of one prepreg or a cured product of a plurality of laminates (hereinafter, may be referred to as a second insulating layer) and a cured product. It is provided with conductor wiring provided on one side or both sides. The printed wiring board is a single-layer printed wiring board (hereinafter, may be referred to as a core board) composed of a second insulating layer and conductor wiring on one side or both sides of the second insulating layer; the conductor wiring of the core board is A second insulating layer (hereinafter, may be referred to as an interlayer insulating layer) and an inner layer conductor wiring (hereinafter, may be referred to as an inner layer conductor wiring) are alternately formed on the formed surface to form an outermost layer. Includes a multi-layer printed wiring board on which conductor wiring is formed. The number of layers of the printed wiring board having a multi-layer structure is not particularly limited.

Since the second insulating layer is made of the cured product of the above prepreg, the material properties of the second insulating layer are equivalent to the material properties of the cured product of the above prepreg. That is, the second insulating layer has a glass transition temperature (Tg) of 220 ° C. or lower and an elastic modulus of 10 GPa or less at 260 ° C. Therefore, if the printed wiring board according to the present embodiment is used as the material of the semiconductor package, the amount of warpage of the semiconductor package due to the temperature change can be reduced.

The CTE (X, Y) of the second insulating layer is preferably 5 ppm / ° C. or less. When the CTE (X, Y) of the second insulating layer is within the above range, the printed wiring board includes the first insulating layer having a low CTE (X, Y) and a low elastic modulus at 260 ° C., and thus the temperature. Warpage is less likely to occur due to changes.

The method for manufacturing a printed wiring board having a single-layer structure is not particularly limited, and for example, a subtractive method in which a part of the metal foil of the metal-clad laminate is removed by etching to form a conductor wiring; All of the metal foil of the stretched laminate is removed by etching to obtain a cured product of the laminate, and a thin electrolytic plating layer by electrolytic plating is formed on one or both sides of the cured product of the obtained laminate to form a plating resist. After protecting the non-circuit forming part by etching, the electrolytic plating layer is thickened on the circuit forming part by electrolytic plating, then the plating resist is removed, and the electroless plating layer other than the circuit forming part is removed by etching to form the conductor wiring. Examples include the semi-additive method of forming. The method for manufacturing the printed wiring board having a multi-layer structure is not particularly limited, and examples thereof include a build-up process.

Hereinafter, the present invention will be specifically described with reference to Examples.

[Examples 1 to 7 and Comparative Examples 1 to 3]
(Resin composition)
The following materials were prepared as raw materials for the resin composition.
<Epoxy resin (A)>
-Product name "NC3000" (biphenyl aralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 275 g / eq)
-Product name "N690" (cresol novolac type epoxy resin, manufactured by DIC Corporation, epoxy equivalent: 215 g / eq))
-Product name "HP9500" (naphthalene type epoxy resin, manufactured by DIC Corporation, epoxy equivalent: 230 g / eq))
-Product name "EPPN502H" (triphenylmethane type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 170 g / eq)
Epoxy equivalents are catalog values.
<Phenolic resin (B)>
-Product name "GPH-103" (biphenyl aralkyl type phenol resin, Nippon Kayaku Co., Ltd., hydroxyl group equivalent: 230 g / eq)
-Product name "MEH-7800" (cresol novolac type phenol resin, Meiwa Kasei Co., Ltd., hydroxyl group equivalent: 180 g / eq)
-Product name "TD2090" (Novolac type phenolic resin, manufactured by DIC Corporation, hydroxyl group equivalent: 105 g / eq)
The hydroxyl group equivalent is a catalog value.
<Low elastic component (C)>
-Product name "SG-P3 Mw1" (acrylic rubber, manufactured by Nagase ChemteX Corporation)
This acrylic rubber (product name "SG-P3Mw1") is a repeating unit represented by the above formulas (1) and (2) in the molecule (R1 in the formula (1) is a hydrogen atom, and R2 in the formula (2) is butyl. It is a resin having a group (which is an ethyl group), an epoxy group, and no unsaturated bond between carbon atoms. This acrylic rubber (product name "SG-P3Mw1") has an epoxy value of 0.21 eq / kg and a weight average molecular weight of 260,000.
-Product name "SG-P3 Kai 197" (acrylic rubber, manufactured by Nagase ChemteX Corporation)
This acrylic rubber (product name "SG-P3 Kai 197") has an epoxy value of 0.17 eq / kg and a weight average molecular weight of 700,000.
<Inorganic filler (D)>
-Product name "SC-2500GNO" (spherical silica, manufactured by Admatex Co., Ltd., average particle size 0.5 μm)
<Curing accelerator>
-Product name "2E4MZ" (imidazole, manufactured by Shikoku Chemicals Corporation).

Epoxy resin (A), phenol resin (B), low elastic component (C), inorganic filler (D) and curing accelerator are blended in the ratios shown in Table 1, diluted with a solvent (methyl ethyl ketone), and this is mixed. A resin composition was prepared by stirring, mixing and homogenizing.

(Prepreg)
A glass cloth (# 2118 type manufactured by Nitto Boseki Co., Ltd., WTX2118T-107-S199, T glass) was impregnated into the resin composition so that the thickness of the cured product of the prepreg was 100 μm. The resin composition impregnated in the glass cloth was heated and dried by a non-contact type heating unit until it became semi-cured. The heating temperature was 150-160 ° C. As a result, the solvent in the resin composition was removed, and a prepreg containing a glass cloth and a semi-cured product of the resin composition impregnated in the glass cloth was produced. The resin content (resin amount) of the prepreg was 41 parts by mass with respect to 100 parts by mass of the prepreg.

(Metal-clad laminate)
Two prepregs were laminated to obtain a laminate, and a copper foil (thickness: 12 μm) was laminated as a metal foil on both sides of the obtained laminate to obtain a laminate with a copper foil. This laminate with copper foil was heat-press molded to produce a double-sided metal-clad laminate having a thickness of 0.2 mm. The conditions for heat and pressure molding were 210 ° C., 4 MPa, and 120 minutes.

[Measurement of material properties and evaluation of warpage properties]
The coefficient of thermal expansion (CTE (X, Y)), the glass transition temperature (Tg), and the elastic modulus in the direction orthogonal to the thickness direction were measured by the following methods. Further, the moldability, the amount of warpage and the amount of swing were evaluated. Table 1 shows the results of the measurement of material properties and the evaluation of warpage properties.

(Coefficient of thermal expansion)
The copper foil adhered to both sides of the double-sided metal-clad laminate was removed by etching to obtain a cured product of the laminate. By the TMA method (Thermal Mechanical Analysis method), the coefficient of thermal expansion of the cured product of the laminate in the direction orthogonal to the thickness direction under the condition of heating at 10 ° C. of 50 to 260 ° C. is measured, and the measured values are averaged to obtain the coefficient of thermal expansion. (CTE (X, Y)).

(Glass transition temperature (Tg))
The copper foil adhered to both sides of the double-sided metal-clad laminate was removed by etching to obtain a cured product of the laminate (plate thickness 0.2 mmt). The glass cloth is made of a woven fabric in which warp threads and weft threads are woven so as to be substantially orthogonal to each other. A cured product of this laminate was cut at an angle of 45 ° with respect to the warp or weft to prepare a sample having a size of 50 mm × 5 mm. For this sample, tan δ was measured using a dynamic viscoelasticity measuring device (“DMS6100” manufactured by SII Nanotechnology Co., Ltd.) under the tension mode 5 ° C./min temperature rise condition (DMA method), and its peak temperature was measured. Was defined as the glass transition temperature (Tg).

(Elastic modulus)
The copper foil adhered to both sides of the double-sided metal-clad laminate was removed by etching to obtain a cured product of the laminate. A cured product of this laminate was cut at an angle of 45 ° with respect to the warp or weft of the glass cloth to prepare a sample having a size of 50 mm × 5 mm. The elastic modulus (dynamic storage elastic modulus) of the sample was measured in an atmosphere of 30 ° C., 200 ° C. or 260 ° C. by DMA measurement.

(Moldability)
The double-sided metal-clad laminate was cut in the thickness direction. This cut surface was visually observed and observed with a scanning electron microscope (SEM). The moldability was evaluated according to the following criteria based on the presence or absence of voids and blurring on the cut surface.
"A": No voids on the cut surface "B": Very small amount of voids on the cut surface "C": Many voids on the cut surface, or manufacturing a metal-clad laminate What I couldn't do.

(Amount of warpage)
A printed wiring board was manufactured by etching and removing a part of the copper foil adhered to both sides of the double-sided metal-clad laminate by a subtractive method to form a conductor wiring. A semiconductor chip (size: 10 mm × 10 mm × thickness 0.10 mmt) is flip-chip mounted, reflowed (260 ° C.), and then adhesively fixed using an underfill (“CV5300” manufactured by Panasonic Corporation) to form a semiconductor package. (12.5 mm × 12.5 mm × thickness 0.27 mmt) was manufactured.

Then, the semiconductor package is placed in the warp measuring device (“THERMOIRE PS200” manufactured by AKROMETRIX) so that the surface on which the semiconductor chip is mounted faces the lower side, and 30 to 30 by three-dimensional shape measurement based on the shadow moire measurement theory. The amount of warpage of the semiconductor package at 260 ° C. was measured. In Table 1, "+" indicates a state in which the semiconductor package is warped upward (cry shape). “-” Indicates a state in which the semiconductor package is warped downward (smile shape).

(Swing amount)
The swing amount of the semiconductor package was set to the displacement amount of (+) and (−) based on the measured value of the warp amount. Specifically, the swing amount of the semiconductor package was determined by taking the difference between the maximum value and the minimum value of the warp amount when the semiconductor package was heated from 30 ° C. to 260 ° C. and then cooled to 30 ° C. It is considered that the smaller the swing amount, the lower the warp characteristic.

The prepregs of Examples 1 to 7 include a base material of reinforcing fibers and a semi-cured product of a resin composition impregnated in the base material of reinforcing fibers, and have a glass transition temperature (Tg) of 220 ° C. or lower after curing. The resin composition is composed of (A) epoxy resin, (B) phenol resin, (C) low elastic component, and (D) inorganic filler. The epoxy equivalent of the component (A) is 180 g / eq or more, the hydroxyl equivalent of the component (B) is 180 g / eq or more, and the content of the component (D) is the components (A) and (B). It was 130 parts by mass or less with respect to 100 parts by mass in total. Therefore, according to Table 1, the formability was excellent, the CTE (X, Y) was low, and the semiconductor package using the cured product of the prepreg of Examples 1 to 7 had a low swing amount. That is, it was found that if the prepregs of Examples 1 to 7 are used as the material of the semiconductor package, the amount of warpage of the semiconductor package due to the temperature change can be reduced.

On the other hand, the prepregs of Comparative Examples 1 and 2 used a phenol resin (B) having a hydroxyl group equivalent of less than 180 g / eq, and the glass transition temperature (Tg) was over 220 ° C. after curing. Therefore, although the elastic modulus at 260 ° C. was 10 GPa or less, the elastic modulus at 200 ° C. was more than 10 GPa due to the higher glass transition temperature as compared with Examples 1 to 7. That is, the packages of Comparative Examples 1 and 2 had a higher swing amount than the packages of Examples 1 to 7, and a large warp occurred.

The prepreg of Comparative Example 3 uses a phenol resin (B) having a hydroxyl group equivalent of less than 180 g / eq, and the content of the component (D) is 130 parts by mass with respect to a total of 100 parts by mass of the components (A) and (B). It was over the club. Therefore, the elastic modulus at 260 ° C. was 10 GPa or less, but the package of Comparative Example 3 had a higher swing amount than the packages of Examples 1 to 7, and a large warp occurred.

Comparing Examples 1, 4 and 5, it was found that the smaller the content of the inorganic filler (D), the more the warp amount of the semiconductor package due to the temperature change tends to decrease.

Claims (7)

Reinforcing fiber base material and
A prepreg comprising a semi-cured product of a resin composition impregnated in a base material of the reinforcing fiber.
After curing, the glass transition temperature (Tg) is 220 ° C. or lower, and the dynamic storage elastic modulus at 260 ° C. is 10 GPa or less.
The resin composition is
(A) Epoxy resin and
(B) Phenolic resin and
(C) Low elasticity component and
(D) Containing with an inorganic filler,
Wherein component (A), epoxy equivalent comprises der Ru epoxy resin or 180 g / eq,
The component (B), hydroxyl group equivalent comprises 180 g / eq or more 290 g / eq or less der Ru phenolic resin,
The prepreg is characterized in that the content of the component (D) is 130 parts by mass or less with respect to a total of 100 parts by mass of the components (A) and (B). The prepreg of claim 1 wherein the component (C) is characterized by comprising an acrylic rubber. The prepreg according to claim 1 or 2, further characterized in that the dynamic storage elastic modulus at 200 ° C. is 10 GPa or less after curing. The prepreg according to any one of claims 1 to 3, wherein the reinforcing fiber contains glass fiber. The prepreg according to claim 4, wherein the glass fiber contains at least one selected from E glass fiber, T glass fiber, S glass fiber, NE glass fiber, and quartz fiber (Q glass). A cured product of one prepreg or a cured product of a plurality of laminates according to any one of claims 1 to 5.
A metal-clad laminate comprising a metal foil adhered to one side or both sides of the cured product. A cured product of one prepreg or a cured product of a plurality of laminates according to any one of claims 1 to 5.
A printed wiring board including conductor wiring provided on one side or both sides of the cured product.